//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27427 SUBJECT: Swift GRB200324.69: Global MASTER-Net observations report DATE: 20/03/24 16:54:49 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical University) was pointed to the Swift GRB200324.69 (trigger No 963260,14h 50m 44.40s , +35d 58m 04.8s, R=0.05) errorbox 16 sec after notice time and 58 sec after trigger time at 2020-03-24 16:40:06 UT, with upper limit up to 16.3 mag. The observations began at zenith distance = 22 deg. The sun altitude is -36.6 deg. The galactic latitude b = 63 deg., longitude l = 59 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1320927 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 64 | MASTER-Amur | P/ | 10 | 15.8 | 91 | MASTER-Amur | P/ | 20 | 15.9 | 126 | MASTER-Amur | P/ | 20 | 15.9 | 163 | MASTER-Amur | P/ | 30 | 16.1 | 225 | MASTER-Amur | P/ | 40 | 16.3 | 282 | MASTER-Amur | P/ | 50 | 16.3 | 350 | MASTER-Amur | P/ | 60 | 16.3 | 429 | MASTER-Amur | P/ | 60 | 16.3 | 509 | MASTER-Amur | P/ | 60 | 16.2 | 657 | MASTER-Amur | P/ | 60 | 16.3 | The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27428 SUBJECT: GRB 200324A: Swift detection of a burst DATE: 20/03/24 16:57:02 GMT FROM: David Palmer at LANL S. Dichiara (NASA/GSFC/UMCP), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (SSDC), J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU), S. Laha (GSFC/UMBC/CRESST), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sbarrato (INAF-OAB), B. Sbarufatti (PSU) and T. N. Ukwatta (LANL) report on behalf of the Neil Gehrels Swift Observatory Team: At 16:39:07 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 200324A (trigger=963260). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 222.685, +35.968 which is RA(J2000) = 14h 50m 44s Dec(J2000) = +35d 58' 06" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 60 sec. The peak count rate was ~1200 counts/sec (15-350 keV), at ~2 sec after the trigger. The XRT began observing the field at 16:42:11.8 UT, 183.9 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 222.67198, 35.94100 which is equivalent to: RA(J2000) = 14h 50m 41.28s Dec(J2000) = +35d 56' 27.6" with an uncertainty of 3.5 arcseconds (radius, 90% containment). This location is 104 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (1.07 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.9 (+2.21/-1.93) x 10^21 cm^-2 (90% confidence). The initial flux in the 2.5 s image was 1.27e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 194 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01. This source lies within the current (Sector 23) field-of-view of TESS camera 2. Burst Advocate for this burst is S. Dichiara (dichiara AT umd.edu). 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: 27429 SUBJECT: GRB 200324A:MITSuME Akeno optical upper limits DATE: 20/03/24 17:45:42 GMT FROM: Ryohei Hosokawa at Tokyo Institute of Technology R. Hosokawa,R. Adachi, K. L. Murata, M. Oeda, K. Shiraishi, K. Iida, M. Niwano, F. Ogawa, S. Toma, N. Nakamura, Y. Yatsu, and N. Kawai(TokyoTech) report on behalf of the MITSuME collaboration: We searched for the optical counterpart of GRB 200324A (S. Dichiara et al., GCN Circular #27428) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The observation started on 16:42:46 UT. We did not find any new point sources within the Swift XRT circle (S. Dichiara et al., GCN Circular #27428) in all three bands. We obtained the 5-sigma limits as follows. T0+[sec] MID-UT T-EXP[sec] 5-sigma limits ------------------------------------------------------------------------------------------------ 219 16:46:39 420 g'>18.9,Rc>18.6,Ic>17.6 ------------------------------------------------------------------------------------------------ T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used UCAC4 catalog for flux calibration. The magnitudes are expressed in the AB system. The images were processed in real-time through the MITSuME GPU reduction pipeline (Niwano et al. ,in prep; https://github.com/MNiwano/Eclair) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27430 SUBJECT: GRB 200324A: Enhanced Swift-XRT position DATE: 20/03/24 19:14:23 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 1203 s of XRT Photon Counting mode data and 2 UVOT images for GRB 200324A, 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 = 222.67373, +35.94173 which is equivalent to: RA (J2000): 14h 50m 41.70s Dec (J2000): +35d 56' 30.2" with an uncertainty of 1.7 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: 27431 SUBJECT: GRB 200324A: Tautenburg observations DATE: 20/03/24 22:50:57 GMT FROM: Sylvio Klose at TLS Tautenburg B. Stecklum, S. Klose, A. Nicuesa Guelbenzu, S. Melnikov, and F. Ludwig (all Tautenburg) report: We observed the field of GRB 200324A (Dichiara et al., GCN 27428) with the Tautenburg 1.34m Schmidt telescope equipped with the TAUKAM 6k x 6k CCD camera and the wide V-band filter (VB). The transmission curve of this filter closely follows the Gaia GBP filter. Observations started at 20:08:15 UT and consisted of 5x5 min exposures. Inside the enhanced XRT error circle (Beardmore et al., GCN 27430) we do not find any optical transient. Based on Gaia DR2 stars in the field, we provide an upper limit of VB > 22.0 mag (Vega system; 3.5 hr after the burst). We note that only ~5 arcsec north of the center of the XRT error circle lies the faint SDSS-DR8 source J145041.56+355635.6, possibly the GRB host galaxy. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27432 SUBJECT: GRB 200324A: NOT optical upper limit DATE: 20/03/24 23:47:48 GMT FROM: Daniele B Malesani at DTU Space Johan P. U. Fynbo (DAWN/NBI), Daniele B. Malesani (DTU Space), Abel de Burgos Sierra (NOT), Thomas Augusteijn (NOT), report on behalf of a larger collaboration: On 2020 March 24.97 UT (6 hr 39 min after the trigger) we observed the field of GRB 200324A (Dichiara et al., GCN 27428; Beardmore et al., GCN 27430) with the Nordic Optical Telescope equipped with ALFOSC in the SDSS r filter, for a total integration time of 300 s. We find no evidence for afterglow emission above a 3-sigma limit of about 23 mag. Our result is consistent with the non-detection by Stecklum et al. (GCN 27431). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27433 SUBJECT: GRB 200324A: Konkoly Obs. optical upper limit DATE: 20/03/25 03:08:41 GMT FROM: Jozsef Vinko at Konkoly Observatory J. Vinko (Konkoly/ELTE/U Szeged), A. Ordasi (Konkoly), L. Kriskovics (Konkoly), R. Szakats (Konkoly) and A. Pal (Konkoly) report on behalf of the "Transient Astrophyical Objects" project: We observed the field of GRB 200324A (Dichiara et al. GCN 27428; Beardmore et al., GCN 27430; Stecklum et al. GCN 27431; Fynbo et al. GCN 27432) with the 0.8m RC80 robotic telescope at Piszkesteto Mountain Station of Konkoly Observatory through SDSS r' filter on 2020 March 24.88 UT (MJD 58932.885, 4h 36m after the trigger). The total exposure time was 1800 s. The frames were tied to PS1-photometry of local stellar sources. No optical counterpart for the GRB has been detected above the 3-sigma upper limit of 21.7 AB-mag, which is consistent with other reports of non-detection. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27435 SUBJECT: GRB 200324A: Swift-XRT refined Analysis DATE: 20/03/25 05:02:10 GMT FROM: Phil Evans at U of Leicester V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. Melandri (INAF-OAB) and S. Dichiara report on behalf of the Swift-XRT team: We have analysed 6.2 ks of XRT data for GRB 200324A (Dichiara et al. GCN Circ. 27428), from 190 s to 35.9 ks after the BAT trigger. The data comprise 163 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 27430). The light curve can be modelled with an initial power-law decay with an index of alpha=3.61 (+0.29, -0.25), followed by a break at T+434 s to an alpha of 1.03 (+/-0.07). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.48 (+0.13, -0.11). The best-fitting absorption column is 1.49 (+0.28, -0.26) x 10^21 cm^-2, in excess of the Galactic value of 1.1 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.92 (+0.18, -0.17) and a best-fitting absorption column of 2.7 (+/-0.7) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.8 x 10^-11 (5.3 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.7 (+/-0.7) x 10^21 cm^-2 Galactic foreground: 1.1 x 10^20 cm^-2 Excess significance: 6.3 sigma Photon index: 1.92 (+0.18, -0.17) If the light curve continues to decay with a power-law decay index of 1.03, the count rate at T+24 hours will be 8.1 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.1 x 10^-13 (4.4 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00963260. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27436 SUBJECT: GRB 200324A: LCO Optical Upper Limit DATE: 20/03/25 07:21:16 GMT FROM: Robert Strausbaugh at U. of the Virgin Islands R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration: We observed Swift GRB 200324A (Dichiara et al., GCN 27428) with the LCO 1-m Sinistro instrument at the McDonald Observatory, USA site, on March 25, from 6:06 to 6:46 UT (corresponding to 13.28 to 13.95 hours from the GRB trigger time) with the Bessel I and R filters. We performed a series of 5x240s exposures in I and R. We do not detect any sources in the individual frames (nor in stacked images) in the Swift enhanced error region (Beardmore et al., GCN 27430), consistent with other optical non-detections. Using the USNO-B.1 catalog as reference, we obtain the following 3-sigma upper limits: R > 24.21 I > 22.56 R.S. is funded by NSF AST grant #1831682 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27439 SUBJECT: GRB 200324A: Swift/UVOT Upper Limits DATE: 20/03/25 12:48:41 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (UCL-MSSL) and S. Dichiara (NASA/GSFC/UMCP) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 200324A 215 s after the BAT trigger (Dichiara et al., GCN Circ. 27428). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 27430) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 215 365 147 >21.0 u_FC 374 624 246 >20.6 white 215 1376 373 >21.7 v 704 1427 78 >18.9 b 630 1527 97 >19.8 u 374 1327 304 >20.2 w1 754 1477 78 >19.1 w2 1381 1401 19 >19.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27440 SUBJECT: GRB 200324A:: TSHAO optical upper limit DATE: 20/03/25 14:19:13 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI), I. Reva (FAPHI), A. Pozanenko (IKI), M. Krugov (FAPHI), E. Mazaeva (IKI), A. Volnova (IKI) report on behalf of IKI-GRB-FuN: We observed the field of GRB 200324A: (Dichiara et al. GCN 27428) with Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory starting on Mar. 24 (UT) 17:35:57. We found no one object within enhanced Swift-XRT position (Beardmore et al., GCN 27430). Preliminary photometry of the field is following. Date UT start t-T0 Filter Exp. OT Err. UL(3 sigma) (mid, days) (s) 2020-03-24 17:35:57 0.0638 R 4200 n/d n/d 21.3 The photometry is based on nearby SDSS-DR12 stars. RA DEC R(Lupton transformation) 222.719432 35.941281 17.353 222.755165 35.913578 16.314 222.698647 35.902796 16.214 222.827959 35.919356 15.822 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27443 SUBJECT: GRB 200324A, Swift-BAT refined analysis DATE: 20/03/25 21:13:14 GMT FROM: Amy Lien at GSFC T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), S. Dichiara (NASA/GSFC/UMCP), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), 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 200324A (trigger #963260) (Dichiara et al., GCN Circ. 27428). The BAT ground-calculated position is RA, Dec = 222.682, 35.931 deg which is RA(J2000) = 14h 50m 43.7s Dec(J2000) = +35d 55' 51.0" with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a weak pulse that starts at ~T-40 s, peaks at ~T0, and lasts until >~T+80 s. The burst was temporarily out of the BAT FOV from T+100.39 s to T+119.39 s. There might be additional burst emission during this period. Due to this data gap, the standard data analysis pipeline is unable to estimate an accurate T90. The time-averaged spectrum from T-38.1 to T+100.4 sec (before the burst went out of the BAT FOV) is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.72 +- 0.15. The fluence in the 15-150 keV band is 2.3 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.07 sec in the 15-150 keV band is 0.7 +- 0.2 ph/cm2/sec. 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/963260/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27445 SUBJECT: GRB 200324A: AROMA-N Optical Observation DATE: 20/03/26 06:44:11 GMT FROM: Takanori Sakamoto at AGU M. Nakamura, T. Sakamoto (AGU) We observed the field of GRB 200324A detected by Swift (Dichiara et al., GCN Circ. 27428) with the 14-inch AGU Robotic Optical Monitor for Astrophysical object - Narrow (AROMA-N) located at the Sagamihara campus of Aoyama Gakuin University. 22 images of 60 sec, 120 sec, 180 sec and 300 sec exposures were taken in the R filter starting from March 24 16:42:55 (UT) about 228 seconds after the trigger and stopped on March 24 19:06:11 (UT). We do not detect the optical afterglow both in the individual images and the stacked image. The estimated five sigma upper limit of the combined image (total exposure of 3240 sec) is ~17.6 mag using the USNO-B1 catalog.