//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31347 SUBJECT: GRB 220101A: Swift detection of a burst with a bright optical counterpart DATE: 22/01/01 05:32:40 GMT FROM: David Palmer at LANL A. Tohuvavohu (U Toronto), J.D. Gropp (PSU), J. A. Kennea (PSU), A. Y. Lien (U Tampa), D. M. Palmer (LANL), T. M. Parsotan (GSFC/UMBC/CRESSTII), B. Sbarufatti (PSU) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 05:09:55 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 220101A (trigger=1091101). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 1.380, +31.753 which is RA(J2000) = 00h 05m 31s Dec(J2000) = +31d 45' 09" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT lightcurve shows a complex lightcurve extending to at least T+170 with a peak of 7000 counts/s (15-350 keV), at ~89 sec after the trigger. The XRT began observing the field at 05:11:32.2 UT, 80.8 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 1.3561, 31.7702 which is equivalent to: RA(J2000) = 00h 05m 25.46s Dec(J2000) = +31d 46' 12.7" with an uncertainty of 4.7 arcseconds (radius, 90% containment). This location is 95 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 1.30e-08 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 89 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 00:05:24.82 = 1.35340 DEC(J2000) = +31:46:08.5 = 31.76903 with a 90%-confidence error radius of about 0.61 arc sec. This position is 9.3 arc sec. from the center of the XRT error circle. The estimated magnitude is 14.60 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.056. Burst Advocate for this burst is A. Tohuvavohu (aaron.tohu AT gmail.com). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31348 SUBJECT: GRB 220101A: Correction to GCN 31347 DATE: 22/01/01 05:53:46 GMT FROM: Aaron Tohuvavohu at U Toronto GCN circular 31347 incorrectly referred to the BAT trigger number of the burst. The correct trigger number for GRB 220101A is 1091527. I apologize for any confusion this may have caused. Happy new year! //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31349 SUBJECT: GRB 220101A: Enhanced Swift-XRT position DATE: 22/01/01 08:34:16 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 1177 s of XRT Photon Counting mode data and 3 UVOT images for GRB 220101A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 1.35374, +31.76890 which is equivalent to: RA (J2000): 00h 05m 24.90s Dec (J2000): +31d 46' 08.0" with an uncertainty of 2.1 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31350 SUBJECT: GRB 220101A: Fermi-LAT detection DATE: 22/01/01 14:08:57 GMT FROM: Lorenzo Scotton at CNRS/IN2P3/LUPM M. Arimoto (Kanazawa Univ.), L. Scotton (CNRS/IN2P3/LUPM) and F. Longo (University and INFN, Trieste) report on behalf of the Fermi-LAT Collaboration: On January 1st, 2022, Fermi-LAT detected high-energy emission from GRB 220101A, which was also detected by Swift (trigger 1091527, Tohuvavohu et al. GCN Circ. 31347) The best LAT on-ground location is found to be RA, Dec = 1.52, 31.75 (degrees, J2000) with an error radius of 0.46 deg (90% containment, statistical error only). This was 18 deg from the LAT boresight at the time of the Swift trigger: T0 =  05:10:11.5 UT. The data from the Fermi-LAT show a significant increase in the event rate after the Swift trigger that is spatially correlated with the Swift emission (0.14 degrees from the Swift-XRT location) with high significance. The photon flux above 100 MeV in the time interval 0-600s after the Swift trigger is 2.5E-5 +/- 5E-6 ph/cm2/s. The estimated photon index above 100 MeV is -2.46 +/- 0.25. The Fermi-LAT point of contact for this burst is Lorenzo Scotton (lorenzo.scotton AT lupm.in2p3.fr). The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31351 SUBJECT: GRB 220101: Swift/UVOT Detection DATE: 22/01/01 14:09:07 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (UCL-MSSL) and A. Tohuvavohu (U Toronto) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 220101 90 s after the BAT trigger ( Tohuvavohu et al., GCN Circ. 31347). A rapidly decayig source consistent with the XRT position (Osborne et al., GCN Circ. 31349) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 00:05:24.80 = 1.35334 (deg.) Dec (J2000) = +31:46:08.4 = 31.76899 (deg.) with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 90 240 147 14.68 +/- 0.02 v 4448 4647 197 18.70 +/- 0.18 b 3833 4032 197 >19.8 u 3628 5201 334 >20.1 w1 4858 5057 197 >20.1 m2 4652 4852 197 >20.2 w2 4243 4443 197 >20.4 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.056 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31352 SUBJECT: Swift GRB220101.22: Global MASTER-Net observations report DATE: 22/01/01 14:56:30 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, T.Pogrosheva, E.Minkina, A.Chasovnikov, V.Topolev, V.Grinshpun, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev (Irkutsk State University, API), B.L.Carrasco, J.R.Valdes,V.Chavushyan, C.J.Martinez, V.M.Patino Alvarez, M.L.H.Rodriguez (INAOE, OAGH) A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University) MASTER-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB220101.22 (trigger No 1091527,00h 05m 31.20s , +31d 45m 10.8s, R=0.05) errorbox 33798 sec after notice time and 33819 sec after trigger time at 2022-01-01 14:33:51 UT, with upper limit up to 17.0 mag. Observations started at twilight. The observations began at zenith distance = 11 deg. The sun altitude is -8.5 deg. The galactic latitude b = -30 deg., longitude l = 112 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1834316 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 33910 | MASTER-Kislovodsk | C | 180 | 14.5 | 34191 | MASTER-Kislovodsk | C | 180 | 16.1 | 34191 | MASTER-Kislovodsk | C | 180 | 16.8 | 34472 | MASTER-Kislovodsk | C | 180 | 16.3 | 34472 | MASTER-Kislovodsk | C | 180 | 17.0 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31353 SUBJECT: GRB 220101A: Xinglong-2.16m photometry and spectroscopy DATE: 22/01/01 15:51:07 GMT FROM: Dong Xu at NAOC/CAS S.Y. Fu (NAOC), Z.P. Zhu (NAOC, HUST), D. Xu, X. Liu, S.Q. Jiang (NAOC) report on behalf of a larger collaboration: We observed the field of GRB 220101A detected by Swift (Tohuvavohu et al., GCN 31347) and Fermi (Arimoto et al., GCN 31350) using the Xinglong-2.16m telescope equipped with the BFOSC camera. Observations were carried out starting at 09:50:07 UT on 2022-01-01. We firstly obtained 4x300 s frames in each of the B, V, R and I bands, and then 2x1800 s spectroscopy covering ~3800 - 8800 AA. The optical afterglow of the burst (Tohuvavohu et al., GCN 31347) is clearly detected in each of our stacked images in the V, R and I bands, but no in the B band. Preliminary photometry is as follows: Tmid-T0 (hr) Mag MagErr Filter 5.55 >21.43 N/A B 5.45 19.86 0.06 V 5.36 18.65 0.02 R 5.27 17.34 0.01 I The spectrum is in low resolution and rather low S/N. However, a broad absorption feature is evident centering at ~ 6820 AA, which can interpreted as Ly_alpha absorption. Besides Ly_alpha, other weak lines such as Si II, C II, Si IV are also detected at the common redshift of z = 4.61. We thus conclude that z = 4.61 is likely the redshift of the GRB. We thank the great support of the Xinglong-2.16m staff, in particular Junjun Jia, Yinan Zhu, Aiying Zhou, and Jie Zheng. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31354 SUBJECT: GRB 220101A: AGILE detection DATE: 22/01/01 19:53:20 GMT FROM: Alessandro Ursi at INAF/IAPS A. Ursi, E. Menegoni (INAF/IAPS), F. Longo (Univ. Trieste and INFN Trieste), C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), P. Tempesta (TeleSpazio), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Argan, M. Cardillo, C. Casentini, Y. Evangelista, L. Foffano, G. Piano (INAF/IAPS), F. Lucarelli (SSDC, and INAF/OAR), A. Bulgarelli, A. Di Piano, V. Fioretti, F. Fuschino, N. Parmiggiani (INAF/OAS-Bologna), M. Marisaldi (INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team: The AGILE satellite detected the long GRB 220101A at T0 = 2022-01-01 05:11:22 (UTC), reported by Swift BAT (GCN #31347, #31348), Swift XRT (GCN #31349), Swift UVOT (GCN #31351), and Fermi LAT (GCN #31350). The burst is clearly visible in the AGILE scientific ratemeters of the SuperAGILE (SA; 20-60 keV), MiniCALorimeter (MCAL; 0.4-100 MeV), and AntiCoincidence (AC; 50-200 keV) detectors. The event lasted about 80 s and it released a total number of 14577 counts in the SA detector (above a background rate of 100 Hz), 95830 counts in the MCAL detector (above a background rate of 1140 Hz), and 256390 counts in the AC detector (above a background rate of 3215 Hz). The AGILE ratemeters light curves can be found at http://www.agilescienceapp.it/notices/GRB220101A_AGILE_RM.png . The event also triggered a partial high time resolution MCAL data acquisition, from T1 = 2022-01-01 05:11:21.50 +/- 0.01 s (UTC) to T2 = 2022-01-01 05:11:55.74 +/- 0.01 s (UTC), and released 10934 counts in the detector, above a background rate of 570 Hz. The time-integrated spectrum of the burst in this time interval can be fitted in the energy range 0.4-100 MeV with a power-law with ph. ind. = -1.28 (-0.11/+0.11), resulting in a reduced chi-squared of 0.96 (84 d.o.f.) and a fluence of 7.8e-05 ergs/cm^2 (90% confidence level), in the same energy range. We divided the data acquisition into four time intervals: interval a [T0-0.5 s, T0+10.0 s], interval b [T0+10.0 s, T0+17.0 s], interval c [T0+17.0 s, T0+24.0 s], and interval d [T0+24.0 s, T0+34.0 s]. The spectral analysis in the energy range 0.4-100 MeV shows an evolution of the power law photon index in the first stages of the burst, passing from -0.98 to -1.70. Details are reported below: | model | ph. ind. | red chi^2 (dof) | fluence (erg/cm^2) a | PL | 0.98 (-0.29/+0.19) | 1.00 (75) | (1.8+/-0.2)e-5 b | PL | 0.93 (-0.40/+0.22) | 0.98 (75) | (8.3+/-0.8)e-6 c | PL | 1.31 (-0.22/+0.23) | 0.99 (75) | (1.1+/-0.1)e-5 d | PL | 1.70 (-0.13/+0.29) | 1.05 (75) | (2.6+/-0.3)e-5 The MCAL light curve can be found at: http://www.agilescienceapp.it/notices/GRB220101A_AGILE_MCAL.png . Additional analysis of AGILE data is in progress. Automatic MCAL GRB alert Notices can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31355 SUBJECT: GRB 220101A: Swift-XRT refined Analysis DATE: 22/01/01 19:55:21 GMT FROM: Phil Evans at U of Leicester A. D'Ai (INAF-IASFPA), B. Sbarufatti (PSU), D.N. Burrows (PSU), J. D. Gropp (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAB), T. Sbarrato (INAF-OAB) and A. Tohuvavohu report on behalf of the Swift-XRT team: We have analysed 7.1 ks of XRT data for GRB 220101A (Tohuvavohu et al. GCN Circ. 31347), from 73 s to 34.6 ks after the BAT trigger. The data comprise 322 s in Windowed Timing (WT) mode (the first 6 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 31349). The late-time light curve (from T0+3.6 ks) can be modelled with an initial power-law decay with an index of alpha=1.6 (+0.8, -0.4), followed by a break at T+4385 s to an alpha of 5.8 (+0.6, -0.4). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.519 (+0.023, -0.016). The best-fitting absorption column is consistent with the Galactic value of 6.3 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.59 (+/-0.07) and a best-fitting absorption column of 7 (+12, -7) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.2 x 10^-11 (4.6 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Galactic foreground: 6.3 x 10^20 cm^-2 Intrinsic column: 7 (+12, -7) x 10^21 cm^-2 at z=4.61 Photon index: 1.59 (+/-0.07) If the light curve continues to decay with a power-law decay index of 5.8, the count rate at T+24 hours will be 2.8 x 10^-7 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x 10^-17 (1.3 x 10^-17) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01091527. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31356 SUBJECT: GRB 220101A: THO optical observations DATE: 22/01/01 21:29:30 GMT FROM: Veli-Pekka Hentunen at Taurus Hill Obs,A95 Veli-Pekka Hentunen, Markku Nissinen and Esa Heikkinen (Taurus Hill Observatory, Varkaus, Finland) report: We have detected GRB 220101A optical afterglow at Taurus Hill Observatory (A95) using Meade 16" ACF 0.40-m/f8.0 telescope and ASI2600MM Pro CMOS camera. We used Chroma Bessell photometric VRI filters. The observations were started at 2022-01-01 14:40 (UT). The optical afterglow was detected at the position RA 00:05:24.8 and DEC +31:46:09.7. The following magnitudes were obtained from the observations using USNO-B1.0 1217-1802 (V=15.29, R=14.70, I=14.74) as a comparison star: Tmid(h)+T0 Filter Exp. time Mag Mag. Err. 9.733 V 300s >18.7 9.994 I 300s 17.91 0.08 10.168 R 300s 19.26 0.13 10.661 I 3x300s 18.08 0.10 10.835 R 3x300s 19.16 0.13 URL-link to our image: https://www.kassiopeia.net/wp-content/uploads/2022/01/grb220101a_I2_nega_web.jpg //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31357 SUBJECT: GRB 220101A: Liverpool telescope imaging of a high-redshift afterglow DATE: 22/01/01 22:14:13 GMT FROM: Daniel Perley at Liverpool JMU D. A. Perley (LJMU) reports: We acquired multicolor imaging of the optical afterglow of GRB 220101A (Tohuvavohu et al., GCN 31347) using the IO:O camera of the 2m robotic Liverpool Telescope. The afterglow was observed twice in the griz filters on 2022-01-01 UT, with the first epoch taking place between 20:07 and 20:17 and the second between 21:21 and 21:31. Photometry with reference to SDSS secondary standard stars in the field gives the following magnitudes: dt(d) filter mag unc 0.6236 g 21.97 0.10 0.6254 r 19.84 0.03 0.6271 i 18.48 0.03 0.6288 z 18.20 0.03 0.6749 g 22.21 0.13 0.6767 r 19.92 0.03 0.6784 i 18.58 0.03 0.6802 z 18.27 0.03 Magnitudes are given in the SDSS system and uncorrected for extinction. Times are referenced to the BAT trigger time. The colors are consistent with a moderately high-redshift (z = 4-5) afterglow, in agreement with the result of Fu et al. (GCN 31353). DisclaimerNone //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31358 SUBJECT: GRB 220101A: CAHA 2.2m/CAFOS detection DATE: 22/01/01 22:29:15 GMT FROM: Alexander Kann at IAA-CSIC A. de Ugarte Postigo (Obs. Cote d'Azur), D A. Kann (HETH/IAA-CSIC), C. C. Thoene, M. Blazek (both HETH), J. F. Agui Fernandez (HETH/IAA-CSIC), P. Martin, and I. Hermelo (both CAHA) report: We observed the afterglow of GRB 220101A (Swift detection: Tohuvavohu et al., GCN #31347; Fermi/LAT Detection: Arimoto et al., GCN #31350; AGILE detection: Ursi et al., GCN #31354; afterglow detections: Kuin & Tohuvavohu, GCN #31351; Fu et al., GCN #31353; Hentunen et al., GCN #31356; Perley, GCN #31357; redshift z = 4.61: Fu et al., GCN #31353) with CAFOS, mounted on the 2.2 m telescope, at the Calar Alto Observatory (Almeria, Spain). The observation started at 19:35:31 UT on 01 January 2022 (13.47 hr after the GRB) and consisted of 6 x 90 s integrations in the i' band. The afterglow is well-detected in the individual images. Against comparison stars from SDSS, we measure i' = 18.45 +/- 0.03 mag (AB) in the stacked image at mid-time 0.60177 d after the trigger. We note this is a very bright GRB and afterglow, further follow-up is encouraged. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31359 SUBJECT: GRB 220101A: NOT redshift confirmation DATE: 22/01/01 23:43:26 GMT FROM: Daniele B Malesani at Radboud U J. P. U. Fynbo (DAWN/NBI), A. de Ugarte Postigo (Obs. Cote d'Azur), D. Xu (NAOC), D. B. Malesani (Univ. Radobud and DAWN/NBI), B. Milvang-Jensen (DAWN/NBI), J. Viuho (NOT and DAWN/NBI), report on behalf of a larger collaboration: We observed the optical counterpart of GRB 220101A (Tohuvavohu et al., GCN 31347; Arimoto et al., GCN 31350) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC spectrograph. A spectrum with exposure time 4x1200 s (grism #20) was secured starting on 2022 Jan 1.81 UT (14.3 hr after the GRB), under good conditions, and covering the wavelength range 5600-10200 AA. A very clear trace is detected from the afterglow continuum. A deep, broad trough is detected around 6800 AA, which we interpret as due to damped Lyman alpha. A number of narrow absorption features are also clearly visible and allow to determine accurately the GRB redshift. We identify, among others, N V, S II, Si II, Si II*, O I, Ni II, C II, Si IV, C IV, Fe II, Fe II*, and Al II, all at a common redshift z = 4.618. Our results thus fully confirm the finding of Fu et al. (GCN 31353). Nice year start for GRBs: happy 2022 to all GCN readers! //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31360 SUBJECT: GRB 220101A: Fermi GBM Detection DATE: 22/01/02 00:16:28 GMT FROM: Stephen Lesage at Fermi-GBM Team S. Lesage (UAH) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 05:17:12 UT on 01 January 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220101A (trigger 662706616/220101215) which was also detected by Swift-BAT (A. Tohuvavohu et al. 2022, GCN 31347), Swift-XRT (J.P. Osborne et al. 2022, GCN 31349), Fermi-LAT (M. Arimoto et al. 2022, GCN 31350), Swift/UVOT (N. P. M. Kuin et al. 2022, GCN 31351), and AGILE (A. Ursi et al. 2022, GCN 31354). The Fermi GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 38 degrees. The GBM light curve consists of multiple emission episodes with a duration (T90) of about 128 s (10-1000 keV). The time-averaged spectrum from T0-65 to T0+179 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.09 +/- 0.02 and the cutoff energy, parameterized as Epeak, is 330 +/- 15 keV. The event fluence (10-1000 keV) in this time interval is (7.7 +/- 0.1)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+90.4 s in the 10-1000 keV band is 11 +/- 0.3 ph/s/cm^2. A Band function fits the spectrum equally well with Epeak= 290 +/- 18 keV, alpha = -1.06 +/- 0.02 and beta = -2.3 +/- 0.2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog:https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page:https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31361 SUBJECT: GRB220101A: optical afterglow detection from Konkoly Observatory DATE: 22/01/02 00:53:01 GMT FROM: Jozsef Vinko at Konkoly Observator J. Vinko, A. Pal, L. Kriskovics, R. Szakats, K. Vida (Konkoly Observatory, Hungary) report: We observed the field of GRB220101A (Tohuvavohu et al., GCN #31347; Arimoto et al., GCN #31350; AGILE Ursi et al., GCN #31354) with the RC80 robotic telescope at Piszkesteto Station of Konkoly Observatory on 2022 Jan 01 starting at 21:32:18 UT. A series of 5x300 sec frames were collected through Sloan r'- and i' bands. The bright optical afterglow (Kuin & Tohuvavohu, GCN #31351; Fu et al., GCN #31353; Hentunen et al., GCN #31356; Perley, GCN #31357; Ugarte Postigo et al. GCN #31358; Fynbo et al. GCN #31359) is clearly detected on the stacked frames with the following magnitudes, calibrated via nearby PS1 stars: Date UT-middle t-T0(hr) Exp(s) r'(AB-mag) i'(AB-mag) 2022-01-01 21:52:52 16.73 5x300 19.81 +/- 0.12 18.67 +/- 0.14 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31363 SUBJECT: GRB 220101A: Asiago spectroscopic and photometric detection DATE: 22/01/02 01:19:25 GMT FROM: Lina Tomasella at INAF,Padova L. Tomasella (INAF-OAPadova), E. Brocato (INAF-OAAbruzzo), M. D’Onofrio (DFA UniPd), E. Cappellaro, S. Benetti (INAF-OAPadova) On behalf a larger collaboration report: We observed the optical counterpart of GRB 220101A (Tohuvavohu et al., GCN 31347; Arimoto et al., GCN 31350) using the Asiago Copernico and Schmidt Robotic telescopes (INAF-OAPadova). The Copernico Telescope is equipped with the AFOSC spectrograph. A low S/N spectrum was obtained starting on 2022-01-01 UT 22:21:03, covering the wavelength range 3400-8200 AA. As reported by Fu at al., GCN 31353 and by Fymbo et al., GCN 31359, a deep, broad feature is detected around 6800 AA, interpreted as the damped Lyman alpha. Other narrow absorption lines are also detected, which allow to confirm the GRB redshift z = 4.61 The afterglow was observed starting on 2022-01-01 between 22:01 and 22:05 UT using Copernico Telescope with BV filters and with gri Sloan filters (two series) using Schmidt 67/92 Robotic Telescope between 22:08 and 22:25 UT. The afterglow is detected in several individual images. We measure V-Bessel = 20.48 +/- 0.1 mag in the Copernico image taken at UT 22:01. The spectral and photometric analysis results presented above are preliminary; data analysis is ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31364 SUBJECT: GRB 220101A: GMG observation DATE: 22/01/02 03:43:02 GMT FROM: Jirong Mao at Yunnan Obs J. Mao, B.-L. Lun, and J.-M. Bai (YNAO) report: We observed the field of GRB 220101A (Tohuvavohu et al. GCN 31347) with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatories. The observation began at UT 12:31:35, 1, Jan. 2022, about 7.3 hours after the trigger. We clearly detected the afterglow. The preliminary magnitude was measured to be R~19.0. The weather turned to be cloudy, and it prevented us from further observations. We appreciate all the astronomers working during the holidays. Happy new year! //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31365 SUBJECT: GRB 220101A : Eiso equals the maximum isotropic GRB energy DATE: 22/01/02 09:38:15 GMT FROM: Jean-Luc Atteia at IRAP J.-L. Atteia reports: A quick calculation of the isotropic energy of GRB 220101A, whose prompt emission was detected from space by Swift/BAT (A. Tohuvavohu et al. 2022, GCN 31347), Fermi/LAT (M. Arimoto et al. 2022, GCN 31350), AGILE (A. Ursi et al. 2022, GCN 31354), and Fermi/GBM (Lesage et al. 2022, GCN 31360) was done using the redshift z = 4.618 measured at Xinlong (Fu et al. 2022, GCN 31353) and NOT (Fynbo te al. 2022, GCN 31359) and the spectral parameters measured by Fermi/GBM (Lesage et al. 2022, GCN 31360). The isotropic energy of GRB 220101A reaches 3.7 10^54 ergs, equaling the maximum isotropic energy measured for GRBs to date (Atteia et al. 2017, ApJ 837, 119). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31366 SUBJECT: GRB 220101A: OASDG optical observations DATE: 22/01/02 11:29:48 GMT FROM: Luca Izzo at DARK/NBI A. Noschese, L. D’Avino (OASDG), A. Di Dato (INAF/Naples & OASDG), L. Izzo (DARK/NBI) report: We observed the field of GRB 220101A (Tohuvavohu et al., GCN #31347; Arimoto et al., GCN #31350; Ursi et al., GCN #31354) with the 0.5m telescope of the Osservatorio Astronomico S. Di Giacomo located in Agerola, Italy ( https://osservatorio.astrocampania.it/ ). We obtained three sets of 7x180s images in the Rc filter and two sets of 7x180s images in the Ic filter under moderate weather conditions (average humidity ~87%). The afterglow is clearly detected in the stacked Ic images, being quite fainter in the Rc stacked images, at the position reported by Swift-UVOT (Kuin & Tohuvavohu, GCN #31351) and by optical telescopes (Fu et al., GCN #31353; Hentunen et al., GCN #31356; Perley et al., GCN #31357; de Ugarte Postigo et al., GCN #31358; Fynbo et al., GCN #31359; Vinko et al., GCN #31361; Tomasella et al., GCN #31363; Mao et al., GCN #31364). We report the following preliminary magnitudes (AB) Filter Tmid-T0(days) Mag. Delta Mag. Rc 0.568 19.10 0.09 Ic 0.586 18.13 0.07 Rc 0.604 19.40 0.20 Ic 0.620 18.16 0.09 Rc 0.638 19.09 0.17 The calibration was performed using nearby stars in the Pan-STARRS PS1 catalog, using transformation equations to Rc and Ic magnitudes. We want to mention that these observations were done exactly one year after the damage caused to the OASDG instrumentation by a lightning storm. The detection of a GRB at z=4.618 (Fu et al., GCN #31353; Fynbo et al., GCN #31359) during one of the first observing nights following last year's disaster represents a big result for our group. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31368 SUBJECT: GRB 220101A: GMG observation (2nd epoch) DATE: 22/01/02 13:50:03 GMT FROM: Jirong Mao at Yunnan Obs J. Mao, B.-L. Lun, and J.-M. Bai (YNAO) report: We observed the field of GRB 220101A (Tohuvavohu et al. GCN 31347) with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatories again. The observation began at UT 11:39:51, 2, Jan. 2022, about 30.5 hours after the trigger. We still clearly detected the afterglow. The preliminary magnitude was measured to be R~20.1. We encourage the continued follow-up observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31369 SUBJECT: GRB 220101A: Swift-BAT refined analysis DATE: 22/01/02 14:20:30 GMT FROM: Tyler Parsotan at UMBC/GSFC/CRESST II C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU), M. Stamatikos (OSU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 220101A (trigger #1091527) (Tohuvavohu et al. GCN 31347). The BAT ground-calculated position is RA, Dec = 1.360, 31.758 deg which is RA(J2000) = 00h 05m 26.4s Dec(J2000) = +31d 45' 28.3" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 64%. The BAT lightcurve shows a complex lightcurve extending to at least T+170 with a peak of 7000 counts/s (15-350 keV), at ~89 sec after the trigger. T90 (15-350 keV) is 173.36 +- 12.76 sec (estimated error including systematics). The time-averaged spectrum from T-58.08 to T+259.11 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.13 +- 0.13, and Epeak of 249.1 +- 161.8 keV (chi squared 42.49 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 2.5 +- 0.0 x 10^-05 erg/cm2 and the 1-sec peak flux measured from T+89.07 sec in the 15-150 keV band is 7.3 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.34 +- 0.03 (chi squared 50.91 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/1091527/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31370 SUBJECT: GRB 220101A: Tautenburg observations DATE: 22/01/02 14:42:12 GMT FROM: Ana Nicuesa at TLS Tautenburg A. Nicuesa Guelbenzu, S. Klose, S. Melnikov, B. Stecklum, U. Laux (all TLS Tautenburg) report: We observed the field of GRB 220101A (Tohuvavohu et al., GCN 31347) with the Tautenburg 1.34m Schmidt telescope equipped with the TAUKAM 6kx6k CCD camera. Observations were performed on January 1, 2022, at a midtime of 22.14 UT. For the optical transient (Tohuvavohu et al., GCN 31347; Kuin & Tohuvavohu, GCN 31351; Fu et al., GCN 31353; Hentunen et al., GCN 31356; Perley et al., GCN 31357; de Ugarte Postigo et al., GCN 31358; Fynbo et al., GCN 31359; Vinko et al., GCN 31361; Tomasella et al., GCN 31363; Mao et al., GCN 31364; Noschese et al., GCN 31366; Mao et al., GCN 31368) we measure r = 19.86 +/- 0.13 mag (AB), calibrated against the SDSS catalogue. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31371 SUBJECT: GRB 220101A: LCO Optical Observations DATE: 22/01/02 22:42:55 GMT FROM: Robert Strausbaugh at U. of the Virgin Islands R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (College of Marin) report on behalf of a larger collaboration: We observed Swift GRB 220101A (Tohuvavohu, et al., GCN 31347) with the LCO 1-m Sinistro instrument at the Teide, Tenerife site, on January 2, from 21:41 to 22:03 UT (corresponding to 40.53 to 40.90 hours from the GRB trigger time) with the Bessel R and I filters. We performed a series of 3x400s exposures in R and I bands. We clearly detect the source at the UVOT detection coordinates and other optical observations (Tohuvavohu et al., GCN 31347; Kuin & Tohuvavohu, GCN 31351; Fu et al., GCN 31353; Hentunen et al., GCN 31356; Perley et al., GCN 31357; de Ugarte Postigo et al., GCN 31358; Fynbo et al., GCN 31359; Vinko et al., GCN 31361; Tomasella et al., GCN 31363; Mao et al., GCN 31364; Noschese et al., GCN 31366; Mao et al., GCN 31368) in both bands. The following magnitudes are calculated using the USNO-B.1 catalog as reference: R=19.76+/-0.11 I=18.03+/-0.13 These magnitudes are not corrected for galactic extinction. R.S. is funded by NSF AST grant #1831682 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31372 SUBJECT: GRB 220101A: ALMA detection DATE: 22/01/02 23:28:47 GMT FROM: Tanmoy Laskar at U of Bath T. Laskar (Radboud U.) reports on behalf of a larger collaboration: "We observed GRB 220101A (Tohuvavohu et al., GCN 31347) with the Atacama Large Millimeter/Submillimeter Array (ALMA) at 97.5 GHz beginning on 2021 January 02 20:37:22 UT (39.5 h after the burst) Preliminary analysis reveals a mm source with flux density of ~ 0.1 mJy at position: RA (J2000) = 00:05:24.80 Dec (J2000) = +31:46:08.41 with uncertainty ~ 0.03" in each coordinate, consistent with the X-ray position (Osborne et al., GCN 31349) and optical position (Tohuvavohu et al., GCN 31347; Hentunen et al., GCN 31356). Further observations are planned. We thank the JAO staff, AoD, P2G, and the entire ALMA team for their help with these observations." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31373 SUBJECT: GRB 220101A: TNG NIR afterglow detection DATE: 22/01/03 12:20:15 GMT FROM: Paolo D'Avanzo at INAF-OAB P. D'Avanzo (INAF-OAB), A. Melandri, S. Covino (INAF-OAB), V. D'Elia (ASI-SSDC), M. De Pasquale (Univ. Messina), D. B. Malesani (Radboud), S. Piranomonte (INAF-OAR), V. Lorenzi, C. Padilla (INAF-TNG), Paolo Giacobbe (INAF-OATO) on behalf of the CIBO collaboration report: We observed the field of GRB 220101A (Tohuvavohu et al., GCN Circ. 31347; Arimoto et al., GCN Circ. 31350; Ursi et al., GCN Circ. 31354; Lesage & Meegan, GCN Circ. 31360) with the Italian 3.6m TNG telescope equipped with the near-infrared camera NICS. A series of images were obtained with the J, H, K filters on 2022-01-02 from 20:21:15 UT to 21:57:47 UT (i.e. at a mid time of about 1.67 days after the burst). A source is clearly detected in all bands at the optical and mm afterglow position (Kuin & Tohuvavohu, GCN Circ. 31351; Laskar, GCN Circ. 31372). From preliminary photometry we derive the following magnitude: J = 18.29 +/- 0.05 (Vega; calibrated against the 2MASS catalogue). We report the presence of a possibly extended source which lies about 1.8” North with respect to the NIR GRB afterglow. For this source we derive J ~ 20 mag (Vega). We note that this source is present in the CatWISE2020 catalogue (Marocco et al., 2021, ApJSS, 253, 22; arXiv:2012.13084). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31383 SUBJECT: GRB 220101A: LCO Continued Optical Observations DATE: 22/01/04 10:40:05 GMT FROM: Robert Strausbaugh at U. of the Virgin Islands R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (College of Marin) report on behalf of a larger collaboration: We observed Swift GRB 220101A (Tohuvavohu, et al., GCN 31347) for a second time with the LCO 1-m Sinistro instrument at the McDonald Observatory, Texas, USA site, on January 4, from 03:14 to 03:35 UT (corresponding to 69.70 to 70.05 hours from the GRB trigger time) with the Bessel R and I filters. We performed a series of 2x400s exposures in R and I bands. We detect the source at the UVOT detection coordinates and other optical observations (Tohuvavohu et al., GCN 31347; Kuin & Tohuvavohu, GCN 31351; Fu et al., GCN 31353; Hentunen et al., GCN 31356; Perley et al., GCN 31357; de Ugarte Postigo et al., GCN 31358; Fynbo et al., GCN 31359; Vinko et al., GCN 31361; Tomasella et al., GCN 31363; Mao et al., GCN 31364; Noschese et al., GCN 31366; Mao et al., GCN 31368; Guelbenzu, et al., GCN 31370; Strausbaugh et al., GCN 31371, D'Avanzo et al., 31373) in both bands. The following magnitudes are calculated using the USNO-B.1 catalog as reference: R=20.95+/-0.21 I=19.09+/-0.25 These magnitudes are not corrected for galactic extinction. R.S. is funded by NSF AST grant #1831682 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31384 SUBJECT: GRB 220101A: 1.3m DFOT observations DATE: 22/01/04 12:26:23 GMT FROM: Dimple Panchal at ARIES, India Dimple, Ankur Ghosh, Rahul Gupta, Amit Kumar, Amit Ror, Alaxender Panchal, Kuntal Misra and S. B. Pandey (ARIES) report: We carried out the follow-up observations of GRB 220101A (Tohuvavohu, et al., GCN 31347) using 1.3m Devasthal Fast Optical Telescope (DFOT) at Devasthal observatory of Aryabhatta Research Institute of observational sciencES (ARIES), India. The observation was started on 2022-01-01 at 12:45:02 UT. We observed a series of images with an exposure time of 300 seconds in R band covering Swift UVOT position and that provided by other optical observations (Tohuvavohu et al., GCN 31347; Kuin & Tohuvavohu, GCN 31351; Fu et al., GCN 31353; Hentunen et al., GCN 31356; Perley et al., GCN 31357; de Ugarte Postigo et al., GCN 31358; Fynbo et al., GCN 31359; Vinko et al., GCN 31361; Tomasella et al., GCN 31363; Mao et al., GCN 31364; Noschese et al., GCN 31366; Mao et al., GCN 31368; Guelbenzu et al., GCN 31370; Strausbaugh et al., GCN 31371). An uncataloged source is clearly visible at the location of the burst with a magnitude of 18.19+-0.15 in the R-band at around 7.73 hours after the burst. Photometry is done based on the USNO-B1.0 catalog. The magnitude is not corrected for Galactic extinction in the direction of the GRB. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31385 SUBJECT: GRB 220101A: VLA detection DATE: 22/01/04 13:43:49 GMT FROM: Tanmoy Laskar at U of Bath T. Laskar (Radboud U.) reports on behalf of a larger collaboration: "We observed GRB 220101A (Tohuvavohu et al., GCN 31347) with the Karl G. Jansky Very Large Array (VLA) beginning on 2022 January 04 04:00 UT (2.96 d after the burst). At a mean frequency of 6.0 GHz, we detect a radio source with a preliminary flux density of ~ 0.2 mJy at the position: RA (J2000) = 00:05:24.816 +/- 0.005 Dec (J2000) = 31:46:08.37 +/- 0.02 consistent with the X-ray position (Osborne et al., GCN 31349), optical position (Tohuvavohu et al., GCN 31347; Hentunen et al., GCN 31356), and mm-band position (Laskar, GCN 31372). Further observations are planned. We thank the VLA staff for rapidly executing these observations." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31387 SUBJECT: GRB 220101A: iTelescope optical observations DATE: 22/01/04 19:11:01 GMT FROM: Filipp Dmitrievich Romanov at Amateur astronomer I observed the field of GRB 220101A (Tohuvavohu et al., GCN Circ. 31347) using remote telescope T21 (0.43-m f/6.8 reflector + CCD + f/4.5 focal reducer) of iTelescope.Net in Observatory New Mexico Skies at Mayhill (New Mexico, USA). Four images (with exposures 300 seconds, BINx1) were obtained with Ic filter on 2022-01-04 from 01:29:50 to 01:51:05 UTC. I detected faint (SNR ≈ 3) optical afterglow with UVOT position in stacked image (mid time = 01:40:27 UTC, that is 2.854 days after the trigger) and measured its magnitude from comparison to magnitudes of nearby stars from the SDSS Photometric Catalogue, Release 12 (Alam et al., 2015), transformed to Ic by Lupton's (2005) formulas. Measured magnitude (was not corrected for Galactic extinction) = 19.4 +/- 0.4 Ic. Stacked image available here: https://www.flickr.com/photos/filipp-romanov/51800218870 I also observed the field of GRB 220101A remotely with telescope T18 (0.32-m f/8.0 reflector + CCD) in AstroCamp observatory (Nerpio, Spain). I did not detect the source (magnitude limit of about 19 R) in a 300-sec image taken with a red filter, started on 2022-01-02 at 18:40:52 UTC. F. D. Romanov. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31388 SUBJECT: GRB 220101A: 2.2m CAHA (+CAFOS) first day optical detection DATE: 22/01/04 23:06:26 GMT FROM: Youdong HU at IAA-CSIC M. D. Caballero-Garcia, R. Sanchez-Ramirez, Y.-D. Hu, A. J. Castro-Tirado, E. Fernandez-Garcia (IAA-CSIC), G. Bergond and I. Hermelo (CAHA) report: Following the detection of the bright GRB 220101A by Swift (Tohuvavohu et al., GCNC 31347), Fermi (Arimoto et al., GCNC 31350, Lesage et al., GCNC 31360) and AGILE (Ursi et al., GCNC 31354) we observed the optical afterglow (Kuin & Tohuvavohu, GCNC 31351; Fu et al., GCNC 31353; Hentunen et al., GCNC 31356; Perley, GCNC 31357; de Ugarte Postigo et al., GCNC 31358; Vinko et al., GCNC 31361; Tomasella et al., GCNC 31363; Mao et al., GCNC 31364; Noschese et al., GCNC 31366; Mao et al., GCNC 31368; Nicuesa Guelbenzu et al., GCNC 31370; Strausbaugh et al., GCNC 31371; D'Avanzo et al., GCNC 31373; Strausbaugh et al., GCNC 31383; Dimple et al., GCNC 31384; Romanov, GCNC31387) with the CAFOS instrument, mounted on the 2.2 m telescope, at the Calar Alto Observatory (Almeria, Spain). The observation started at 18:12:07 UT on 1st January 2022 (13.78 hr after the GRB) and consisted of 3 x 60 s, 4 x 60 s and 1 x 300 s exposures in the sdss_i, sdss_r and sdss_g bands. Against comparison stars from SDSS, we measure r=19.75+-0.05 for the GRB 220101A optical afterglow. We thank the staff at Calar Alto observatory for their excellent support. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31389 SUBJECT: GRB 220101A: 3rd LCO Optical Observation DATE: 22/01/05 00:16:11 GMT FROM: Robert Strausbaugh at U. of the Virgin Islands R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (College of Marin) report on behalf of a larger collaboration: We observed Swift GRB 220101A (Tohuvavohu, et al., GCN 31347) for a third time with the LCO 1-m Sinistro instrument at the Teide Observatory, Tenerife site, on January 4, from 21:35 to 22:02 UT (corresponding to 88.43 to 88.88 hours from the GRB trigger time) with the Bessel R and I filters. We performed a series of 2x500s exposures in R and I bands. We still detect the source at the UVOT detection coordinates and other optical observations (Tohuvavohu et al., GCN 31347; Kuin & Tohuvavohu, GCN 31351; Fu et al., GCN 31353; Hentunen et al., GCN 31356; Perley et al., GCN 31357; de Ugarte Postigo et al., GCN 31358; Fynbo et al., GCN 31359; Vinko et al., GCN 31361; Tomasella et al., GCN 31363; Mao et al., GCN 31364; Noschese et al., GCN 31366; Mao et al., GCN 31368; Guelbenzu, et al., GCN 31370; Strausbaugh et al., GCN 31371, D'Avanzo et al., GCN 31373; Strausbaugh et al., GCN 31383; Dimple et al., GCN 31384; Romanov, GCN 31387; Caballero-Garcia, GCN 31388) in both bands. The following magnitudes are calculated using the USNO-B.1 catalog as reference: R=21.31+/-0.18 I=20.43+/-0.12 These magnitudes are not corrected for galactic extinction. R.S. is funded by NSF AST grant #1831682 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31390 SUBJECT: GRB 220101A: Mondy optical observations DATE: 22/01/05 13:03:41 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI, HSE), A. Pozanenko (IKI), E. Klunko (ISTP), N. Pankov (HSE) report on behalf of GRB IKI FuN: We observed Swift GRB 220101A (Tohuvavohu, et al., GCN 31347) also detected by Fermi/LAT (M. Arimoto et al. 2022, GCN 31350), AGILE (A. Ursi et al. 2022, GCN 31354), and Fermi/GBM (Lesage et al. 2022, GCN 31360) with AZT-33IK telescope of Sayan observatory (Mondy) starting on 2022-01-04 (UT) 15:16:32. We detect the optical afterglow (Tohuvavohu et al., GCN 31347; Kuin & Tohuvavohu, GCN 31351; Fu et al., GCN 31353; Hentunen et al., GCN 31356; Perley et al., GCN 31357; de Ugarte Postigo et al., GCN 31358; Fynbo et al., GCN 31359; Vinko et al., GCN 31361; Tomasella et al., GCN 31363; Mao et al., GCN 31364; Noschese et al., GCN 31366; Mao et al., GCN 31368; Guelbenzu, et al., GCN 31370; Strausbaugh et al., GCN 31371, D'Avanzo et al., GCN 31373; Strausbaugh et al., GCNs 31383, 31389; Dimple et al., GCN 31384; Romanov, GCN 31387; Caballero-Garcia, GCN 31388). Preliminary photometry of the afterglow in a stacked image is following Date UT start t-T0 Filter Exp. OT Err. UL(3sigma) (mid, days) (s) 2022-01-04 12:36:19 3.33083 R 30*120 21.50 0.12 23.1 The photometry is based on the nearby SDSS-DR12 stars RA DEC R(Lupton) 00:05:20.64408 +31:45:46.0728 18.562 00:05:34.81464 +31:45:50.5224 15.734 00:05:32.53944 +31:44:51.9396 15.369 00:05:36.69864 +31:44:42.4176 14.677 We searched for the nearest galaxy in catalogs. The nearest galaxy was found in Legacy Survey 1.5 arcsec apart from afterglow UVOT position with r=23.98, z=21.33 and not detected in g-filter (Brick: 0013p317, Objid: 4276). The galaxy is not presented in SDSS and PS1 catalogs. This red galaxy might be a host galaxy of GRB 220101A, in this case the distance from the source to the center of the galaxy will be about 10 kpc at redshift z = 4.618 (Fu et al., GCN 31353; Fynbo et al., GCN 31359; Tomasella et al., GCN 31363). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31394 SUBJECT: GRB 220101A: continued 1.3m DFOT Optical Observations DATE: 22/01/06 07:39:50 GMT FROM: Rahul Gupta at ARIES, India Amit Ror, Rahul Gupta, Amit Kumar, Dimple, Ankur Ghosh, Amar Aryan, B. Kumar, S. B. Pandey, and K. Misra (ARIES) report: We further observed the bright GRB 220101A (Tohuvavohu, et al., GCN 31347) with 1.3m Devasthal Fast Optical Telescope (DFOT) located at Devasthal observatory of Aryabhatta Research Institute of Observational Sciences (ARIES), India. The observation was started on 2022-01-02 at 13:39:49 UT. We obtained a series of images with an exposure time of 300 seconds in R, and I filters, respectively. We clearly detected the optical afterglow of GRB 220101A (Tohuvavohu et al., GCN 31347; Kuin & Tohuvavohu, GCN 31351; Fu et al., GCN 31353; Hentunen et al., GCN 31356; Perley, GCN 31357; de Ugarte Postigo et al., GCN 31358; Fynbo et al., GCN 31359; Vinko et al., GCN 31361; Tomasella et al., GCN 31363; Mao et al., GCNs 31364, 31368; Noschese et al., GCN 31366; Guelbenzu et al., GCN 31370; Strausbaugh et al., GCNs 31371, 31383, 31389; Dimple et al., GCN 31384; Romanov, GCN 31387; Caballero-Garcia et al., GCN 31388; and Belkin et al., GCN 31390) in our individual images of both the filters. We report the preliminary brightness of the afterglow to be R = 19.46 +/- 0.06 mag ~ 32.50 hours post burst. The reported magnitude value is not corrected for the Galactic extinction in the direction of the burst. Photometric calibration is performed using the standard stars from the USNO-B1.0 catalog. This circular may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31395 SUBJECT: GRB 220101A: further TNG NIR observations DATE: 22/01/06 12:52:54 GMT FROM: Paolo D'Avanzo at INAF-OAB P. D'Avanzo (INAF-OAB), A. Melandri (INAF-OAB), D. Fugazza (INAF-OAB), S. Campana (INAF-OAB), D. B. Malesani (Radboud Univ. and DAWN/NBI), V. D'Elia (ASI-SSDC), M. De Pasquale (Univ. Messina), E. Palazzi (INAF-OAS), S. Piranomonte (INAF-OAR), A. Rossi (INAF-OAS), G. Tagliaferri (INAF-OAB); V. Lorenzi, D. Carosati (INAF-TNG), Paolo Giacobbe (INAF-OATO) on behalf of the CIBO collaboration report: We observed the field of GRB 220101A (Tohuvavohu et al., GCN Circ. 31347; Arimoto et al., GCN Circ. 31350; Ursi et al., GCN Circ. 31354; Lesage & Meegan, GCN Circ. 31360) with the Italian 3.6m TNG telescope equipped with the near-infrared camera NICS. A series of images were obtained with the J and K filters on 2022-01-05 from 19:31:36 UT to 20:55:35 UT (i.e. at a mid time of about 4.63 days after the burst). The NIR afterglow (D’Avanzo et al., GCN Circ. 31373) is clearly detected in all bands. From preliminary photometry we derive the following magnitude: J = 19.71 +/- 0.10 (Vega; calibrated against the 2MASS catalogue). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31398 SUBJECT: GRB 220101A: Continued Mondy optical observations DATE: 22/01/07 12:25:31 GMT FROM: Alexei Pozanenko at IKI, Moscow N. Pankov (HSE), A. Pozanenko (IKI), E. Klunko (ISTP), Belkin (IKI, HSE) report on behalf of GRB IKI FuN: We observed Swift GRB 220101A (Tohuvavohu, et al., GCN 31347) also detected by Fermi/LAT (Arimoto et al. 2022, GCN 31350), AGILE (Ursi et al. 2022, GCN 31354), and Fermi/GBM (Lesage et al. 2022, GCN 31360) with AZT-33IK telescope of Sayan observatory (Mondy) starting on 2022-01-06 (UT) 13:57:13. We detected the afterglow (Tohuvavohu et al., GCN 31347; Kuin & Tohuvavohu, GCN 31351; Fu et al., GCN 31353; Hentunen et al., GCN 31356; Perley et al., GCN 31357; de Ugarte Postigo et al., GCN 31358; Fynbo et al., GCN 31359; Vinko et al., GCN 31361; Tomasella et al., GCN 31363; Mao et al., GCN 31364; Noschese et al., GCN 31366; Mao et al., GCN 31368; Guelbenzu, et al., GCN 31370; Strausbaugh et al., GCN 31371, D'Avanzo et al., GCN 31373; Strausbaugh et al., GCNs 31383, 31389; Dimple et al., GCN 31384; Romanov, GCN 31387; Caballero-Garcia, GCN 31388; Belkin et al, GCN 31390; Gupta et al, GCN 31394; D'Avanzo et al, GCN 31395) in a stacked image. Preliminary photometry of the afterglow is following Date UT start t-T0 Filter Exp. OT Err. UL(3sigma) (mid, days) (s) 2022-01-06 13:57:13 5.38683 R 30*120 22.17 0.18 23.0 The photometry is based on the nearby SDSS-DR12 stars RA DEC R(Lupton) 00:05:20.64408 +31:45:46.0728 18.562 00:05:34.81464 +31:45:50.5224 15.734 00:05:32.53944 +31:44:51.9396 15.369 00:05:36.69864 +31:44:42.4176 14.677 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31401 SUBJECT: GRB 220101A: Tautenburg observations DATE: 22/01/07 18:12:34 GMT FROM: Sylvio Klose at TLS Tautenburg A. Nicuesa Guelbenzu, S. Melnikov, S. Klose, B. Stecklum, F. Ludwig (all TLS Tautenburg) report: We continued observing the field of GRB 220101A (Tohuvavohu et al., GCN 31347) with the Tautenburg 1.34m Schmidt telescope equipped with the TAUKAM 6kx6k CCD camera (Stecklum et al. 2021; arXiv:2101.12554). For the optical transient (discovered by Swift/UVOT: Tohuvavohu et al., GCN 31347; Kuin et al., GCN 31351) we measure the following AB magnitudes: g > 22.9 (3 sigma), January 6, 20:23 UT (midtime), r = 22.54 +/- 0.24, January 6, 19:32 UT (midtime), i = 21.27 +/- 0.10, January 6, 18:44 UT (midtime), z = 21.17 +/- 0.22, January 6, 18:26 UT (midtime), calibrated against the SDSS catalogue. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31420 SUBJECT: GRB 220101A: SAO RAS optical observations DATE: 22/01/09 14:22:05 GMT FROM: Alexei Pozanenko at IKI, Moscow A. S. Moskvitin (SAO), N. Pankov (HSE, IKI), A. S. Medvedev (SAO), S. Belkin (IKI), A. Pozanenko (IKI) report on behalf of GRB IKI FuN: We observed Swift GRB 220101A (Tohuvavohu, et al., GCN 31347) also detected by Fermi/LAT (Arimoto et al. 2022, GCN 31350), AGILE (Ursi et al. 2022, GCN 31354), and Fermi/GBM (Lesage et al. 2022, GCN 31360) with Zeiss-1000 telescope of SAO RAS in Rc-filter starting on 2022-01-08 (UT) 15:40:16. We detected the afterglow (Tohuvavohu et al., GCN 31347; Kuin & Tohuvavohu, GCN 31351; Fu et al., GCN 31353; Hentunen et al., GCN 31356; Perley et al., GCN 31357; de Ugarte Postigo et al., GCN 31358; Fynbo et al., GCN 31359; Vinko et al., GCN 31361; Tomasella et al., GCN 31363; Mao et al., GCN 31364; Noschese et al., GCN 31366; Mao et al., GCN 31368; Guelbenzu, et al., GCNs 31370, 31401; Strausbaugh et al., GCN 31371; D'Avanzo et al., GCN 31373; Strausbaugh et al., GCNs 31383, 31389; Dimple et al., GCN 31384; Romanov, GCN 31387; Caballero-Garcia, GCN 31388; Belkin et al., GCNs 31390, 31398; Gupta et al., GCN 31394; D'Avanzo et al., GCN 31395) in a stacked image. Preliminary photometry of the afterglow is following Date UT start t-T0 Filter Exp. OT Err. UL(3sigma) (mid, days) (s) 2022-01-08 15:40:16 7.46534 Rc 16*300 22.8 0.3 23.2 The photometry is based on the nearby SDSS-DR12 stars RA DEC R(Lupton transformations) 00:05:20.64408 +31:45:46.0728 18.562 00:05:34.81464 +31:45:50.5224 15.734 00:05:32.53944 +31:44:51.9396 15.369 00:05:36.69864 +31:44:42.4176 14.677 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31425 SUBJECT: GRB 220101A: Additional Liverpool telescope photometry DATE: 22/01/09 20:17:08 GMT FROM: Daniel Perley at Liverpool JMU D. A. Perley (LJMU) reports: We acquired additional multicolor imaging of the optical afterglow of GRB 220101A (Tohuvavohu et al., GCN 31347) using the IO:O camera of the 2m robotic Liverpool Telescope, on the nights (UT) of 2022-01-02, 2022-01-03, 2022-01-04, 2022-01-05, and 2022-01-07. Photometry with reference to SDSS secondary standard stars in the field gives the following magnitudes: dt(d) filter mag unc 1.5924 r 21.17 0.06 1.5958 i 19.70 0.04 1.5991 z 19.48 0.05 2.7070 z 19.97 0.12 2.7120 i 20.39 0.08 2.7154 r 21.58 0.17 3.6932 z 20.61 0.12 3.6983 r 22.31 0.17 3.7032 i 20.89 0.09 4.5961 z 20.63 0.11 4.6011 i 21.25 0.11 4.6045 r 23.13 0.34 6.7021 i 21.34 0.19 Magnitudes are given in the SDSS system and uncorrected for extinction. Times are referenced to the BAT trigger time. DisclaimerNone //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31433 SUBJECT: Konus-Wind detection of GRB 220101A DATE: 22/01/11 18:45:24 GMT FROM: Anastasia Tsvetkova at Ioffe Institute A. Tsvetkova, D. Frederiks, A. Lysenko, A. Ridnaia, D. Svinkin, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report: The long-duration, bright GRB 220101A (Swift-BAT trigger #1091101: Tohuvavohu  et al., GCN 31347; Markwardt et al., GCN 31369; Fermi-LAT detection: Arimoto et al., GCN 31350; AGILE detection: Ursi et al., GCN 31354; Fermi-GBM detection: Lesage & Meegan, GCN 31360) triggered Konus-Wind at T0=18695.828 s UT (05:11:35.828). The burst light curve shows a bright, multi-peaked pulse which starts at ~T0-147 s and has a total duration of~237 s. The emission is seen up to ~15 MeV. The total energy fluence of the burst is 9.05(-0.55,+0.60) erg/cm^2 and the 64-ms peak energy flux, measured from T0 + 18.624 s, is 4.0(-0.7, +0.7)x10^-6 erg/cm^2/s (both in the 10 keV - 10 MeV energy range). The time-averaged spectrum (measured from T0 to T0+90.112 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.58 (-0.13,+0.15), the high energy photon index beta = -2.62 (-0.53,+0.25), the peak energy Ep = 257 (-27,+28) keV, chi2 = 126/119 dof. The spectrum near the peak count rate (measured from T0+16.640 to T0+24.576 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.51 (-0.16,+0.18), the high energy photon index beta = -2.55 (-0.64,+0.31), the peak energy Ep = 314 (-39,+43) keV, chi2 = 105/96 dof. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB220101_T18695/ Assuming the redshift z = 4.618 (Fynbo et al., GCN 31359) and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014), we estimate the following burst rest-frame parameters: the isotropic energy release Eiso = 3.64(-0.22,+0.25)x10^54 erg, which is in agreement with Atteia, GCN 31365; the isotropic luminosity Liso = 9.05(-1.58,+1.58)x10^53 erg/s; the rest-frame peak energy of the time-integrated spectrum Epi,z = 1416(-157,+152) keV; and the rest-frame peak energy of the 'peak' spectrum Epp,z = 1764(-219,+242) keV. With these values, GRB 220101A is within 68% prediction bands for for both 'Amati' and 'Yonetoku' relations for the sample of >300 long KW GRBs with known redshifts (Tsvetkova et al., 2021, ApJ, 908, 83), see http://www.ioffe.ru/LEA/GRBs/GRB220101_T18695/GRB220101A_rest_frame.pdf. All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31436 SUBJECT: Konus-Wind detection of GRB 220101A (correction to GCN 31433) DATE: 22/01/11 20:01:39 GMT FROM: Anastasia Tsvetkova at Ioffe Institute A. Tsvetkova, on behalf of the Konus-Wind team: Reported in GCN 31433, the total energy fluence of GRB 220101A misses the exponent. The correct fluence value is 9.05(-0.55,+0.60)x10^-5 erg/cm^2. We thank Jean-Luc Atteia for pointing this out and apologize for possible inconvenience. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31442 SUBJECT: GRB 220101A: continued 1.3m DFOT optical observations of a high-redshift afterglow DATE: 22/01/12 11:11:42 GMT FROM: Amit Kumar at ARIES, India Amit Kumar, Rahul Gupta, Amit Ror, Ankur Ghosh, Dimple, Amar Aryan, Brajesh Kumar, S. B. Pandey, and K. Misra (ARIES) report: We further observed the optical afterglow of the Swift detected GRB 220101A (Tohuvavohu et al., GCN 31347) at z = 4.618 (Fu et al., GCN 31353; Fynbo et al., GCN 31359) with the 1.3m Devsthal Fast Optical Telescope (DFOT) at Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital (India), from 2022-01-03 UT 12:54:68 to 2022-01-03 UT 15:04:14 (from ~55.75 to 57.91 hours after the burst). We obtained 40 frames each of 120 seconds in Bessell R and I filters. We clearly detected the optical afterglow of GRB 220101A in stacked frames within the Swift XRT enhanced error circle (Tohuvavohu et al., GCN 31347) as also reported by Kuin & Tohuvavohu, GCN 31351; Fu et al., GCN 31353; Hentunen et al., GCN 31356; Perley, GCN 31357; de Ugarte Postigo et al., GCN 31358; Fynbo et al., GCN 31359; Vinko et al., GCN 31361; Tomasella et al., GCN 31363; Mao et al., GCNs 31364, 31368; Noschese et al., GCN 31366; Guelbenzu et al., GCN 31370; Strausbaugh et al., GCNs 31371, 31383, 31389; Dimple et al., GCN 31384; Romanov, GCN 31387; Caballero-Garcia et al., GCN 31388; Belkin et al., GCN 31390; Ror et al., GCN 31394; Avanzo et al., GCN 31395; Pankov et al., GCN 31398; Guelbenzu et al., GCN 31401; Moskvitin et al., GCN 31420; and Perley, GCN 31425. The estimated preliminary magnitudes for the R and I-band images are as follows: T_start-T0(hours) Filter Magnitude (mag) ----------------------------------------------------------------------- 55.75 I 19.52 +- 0.02 57.91 R 20.95 +- 0.04 Aperture photometry is performed, and calibration is done based on the standard stars in the USNO-B1.0 catalogue. The quoted magnitudes are not corrected for the Galactic extinction in the direction of GRB 220101A. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31465 SUBJECT: GRB 220101A: The most powerful GRB and BDHN I in 26 years DATE: 22/01/17 11:00:26 GMT FROM: Remo Rufinni at ICRA R. Ruffini, Y. Aimuratov, L. Becerra, C.L. Bianco, Y-C. Chen, C. Cherubini, Y.F. Cai, S. Eslamzadeh, S. Filippi, M. Karlica, Liang Li, G.J. Mathews, R. Moradi, M. Muccino, G.B, Pisani, F. Rastegar Nia, J.A. Rueda, N. Sahakyan, Y. Wang, S.S. Xue, Y.F. Yuan, Y.L. Zheng, on behalf of ICRA, ICRANet and USTC team, report: GRB 220101A, first detected by Swift (Tohuvavohu et al., GCN 31347) with redshift z=4.618 (Fu et al 2022., GCN 31353; Fynbo et al 2022., GCN 31359) and energy of 3.7E54 (J.-L. Atteia 2022, GCN 31365) is categorized as a BdHN I with the most powerful and the highest ever observed X-ray afterglow luminosity in 26 years, as well as the highest supernova rise (SN-rise) and the new neutron star rise (vNS-rise) (Ruffini et al. 2021 MNRAS, 504, 5301) see Fig. 1. There is evidence for the ultrarelativistic prompt emission (UPE) phase (Moradi et al. 2021 PRD 104, 063043). We encourage optical and radio observations to identify the corresponding UPE phase as well as the synchrotron emission originating from the spinning vNS. Fig. 1: http://www.icranet.org/figure1.pdf //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31471 SUBJECT: GRB 220101A: TSHAO optical observation, Terskol, AbAO upper limits DATE: 22/01/17 22:02:27 GMT FROM: Alexei Pozanenko at IKI, Moscow N. Pankov (HSE), A. Pozanenko (IKI), A. Kusakin (FAP), I. Reva (FAP), R. Ya. Inasaridze (AbAO), V. Agletdinov (KIAM), S. Belkin (IKI, HSE), I. Sokolov (KIAM), M. Krugov (FAP) report on behalf of GRB IKI FuN: We observed Swift GRB 220101A (Tohuvavohu, et al., GCN 31347) also detected by Fermi/LAT (Arimoto et al. 2022, GCN 31350), AGILE (Ursi et al. 2022, GCN 31354), Fermi/GBM (Lesage et al. 2022, GCN 31360), and Konus-Wind (Tsvetkova et al., GCN 31433) with Zeiss-1000 telescope of THSAO observatory (Kazakhstan) in R-filter starting on 2022-01-05 (UT) 14:39:20. We were also observing the afterglow position with with AS-32 telescope of Abastumani observatory (AbAO) and K-800 telescope of Mnt. Terskol observatory on 2022-01-06. The afterglow (Tohuvavohu et al., GCN 31347; Kuin & Tohuvavohu, GCN 31351; Fu et al., GCN 31353; Hentunen et al., GCN 31356; Perley et al., GCN 31357; de Ugarte Postigo et al., GCN 31358; Fynbo et al., GCN 31359; Vinko et al., GCN 31361; Tomasella et al., GCN 31363; Mao et al., GCN 31364; Noschese et al., GCN 31366; Mao et al., GCN 31368; Guelbenzu, et al., GCNs 31370, 31401; Strausbaugh et al., GCN 31371; D'Avanzo et al., GCN 31373; Strausbaugh et al., GCNs 31383, 31389; Dimple et al., GCN 31384; Romanov, GCN 31387; Caballero-Garcia, GCN 31388; Belkin et al., GCNs 31390, 31398; Gupta et al., GCN 31394; D'Avanzo et al., GCN 31395; Pankov et al., GCN 31398; Moskvitin et al., GCN 31420; Perley, GCN 31425; Kumar et al., GCN 31442) is detected in THSAO observation, and upper limits obtained in Terskol K-800 and AbAO AS-32 observations. Preliminary photometry of the afterglow and upper limits is following Date UT start t-T0 Filter Exp. OT Err UL(3sigma) Telescope 2022-01-05 14:39:20 4.42129 R 25*180 22.19 0.23 22.5 Zeiss-1000 2022-01-06 15:06:30 5.45091 R 106*60 n/d n/d 21.9 AS-32 2022-01-06 17:21:42 5.51841 Clear 30*60 n/d n/d 21.5 K-800 The photometry is based on the nearby SDSS-DR12 stars RA DEC R(Lupton transformations) 00:05:20.64408 +31:45:46.0728 18.562 00:05:34.81464 +31:45:50.5224 15.734 00:05:32.53944 +31:44:51.9396 15.369 00:05:36.69864 +31:44:42.4176 14.677 Based on multiple observations cited above and our own observations the light curve in R-filter can be approximated by a single power law (after one day after the trigger) with the power law index of -1.9. The light curve can be be found in http://grb.rssi.ru/GRB220101A/GRB220101A_LC.png //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31504 SUBJECT: GRB 220101A: KAO optical-R observation DATE: 22/01/20 14:03:51 GMT FROM: Ahmed Fouad at NRIAG Ahmed M. Fouad (NRIAG), Ali Takey (NRIAG), Dia Fouda (NRIAG) and Ola Ali (NRIAG) report: We observed the optical counterpart of GRB 220101A (Tohuvavohu et al., GCN 31347; Arimoto et al., GCN 31350) using 1.88-m telescope at the Kottamia Astronomical Observatory (KAO), NRIAG, Egypt. The source was visible at RA: 00:05:24.77, DEC: +31:46:08.7 , 9.72 arc seconds from the XRT position. We measured R-Bessel magnitude = 21.5 +/- 0.616 in a combined image of 3x90 seconds images taken at 17:10:00 UT on 3-Jan-2022, 60 hr after the BAT trigger. Photometry was done based on the brightest 10 stars around the GRB in a FoV = 8' x 8', selected from the USNO-A1.0 catalog. The magnitude is not corrected for Galactic extinction in the direction of the GRB. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31648 SUBJECT: GRB 220101A: The first example of a Petanova DATE: 22/02/25 11:38:50 GMT FROM: Remo Rufinni at ICRA R. Ruffini, Y. Aimuratov, L. Becerra, C.L. Bianco, Y-C. Chen, C. Cherubini, Y.F. Cai, S. Eslamzadeh, S. Filippi, M. Karlica, Liang Li, G.J. Mathews, R. Moradi, M. Muccino, G.B, Pisani, F. Rastegar Nia, J.A. Rueda, N. Sahakyan, Y. Wang, S.S. Xue, Y.F. Yuan, Y.L. Zheng, on behalf of ICRA, ICRANet and USTC team, report: We confirm the results of our previous GCN (Ruffini et al. 2022, GCN 31465). Following the release of the X-ray afterglow (Tohuvavohu et al. 2022, GCN 31347) and the GeV data (Arimoto et al. 2022, GCN 31350) of this source, we can estimate the total (keV+MeV+GeV) isotropic energy (see e.g. Ruffini et al. 2021, MNRAS 504, 5301) to be ~6E54 erg, making this GRB the most powerful GRB in 26 years (a "Petanova"). The period of the new neutron star (see e.g. Ruffini et al. 2021, MNRAS 504, 5301) generating the X-ray afterglow is ~1 ms, the initial mass of the BH (see e.g. Ruffini et al. 2019 ApJ 886, 82) is 6.15 solar mass, the spin parameter is 0.95, and the irreducible mass is 4.98 solar masses (see Fig. 1). The peak of the bolometric flux of supernova is of the order of 1E-17 erg/s/cm^2 and will appear in 73+/-15 days after the GRB trigger, with emissions lasting ~ one month peaking in different infrared bands. The observational follow up of this source is encouraged. Fig. 1: http://www.icranet.org/docs/GRB220101A.pdf