//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32191 SUBJECT: GRB 220611A: Swift detection of a burst DATE: 22/06/11 18:36:01 GMT FROM: David Palmer at LANL S. B. Cenko (GSFC), E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC), V. D'Elia (SSDC & INAF-OAR), J.D. Gropp (PSU), J. A. Kennea (PSU), S. Laha (GSFC/UMBC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team: At 18:01:51 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 220611A (trigger=1110090). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 66.526d, -37.289d which is RA(J2000) = 04h 26m 06s Dec(J2000) = -37d 17' 20 with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Due to a telemetry gap, the BAT onboard lightcurve is not immediately available. However, the triggering algorithm found the source in an 8 second image, indicating a long GRB. The XRT began observing the field at 18:04:20.4 UT, 149.2 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 66.51418, -37.25899 which is equivalent to: RA(J2000) = 04h 26m 03.40s Dec(J2000) = -37d 15' 32.4" with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 113 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. We cannot determine whether the source is fading at the present time. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 2.66 x 10^20 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 152 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 none of the XRT error circle. 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 0.033. We note that this source location is ~15 arcsec from the line of sight to the galaxy MCG-06-10-007, which is described in Simbad as an S0 galaxy, B=16.3, z~0.049, angular size 18"x16". Burst Advocate for this burst is S. B. Cenko (brad.cenko AT nasa.gov). 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: 32192 SUBJECT: GRB 220611A: Enhanced Swift-XRT position DATE: 22/06/11 20:54:10 GMT FROM: Phil Evans at U of Leicester M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 496 s of XRT Photon Counting mode data and 1 UVOT images for GRB 220611A, 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 = 66.51464, -37.26019 which is equivalent to: RA (J2000): 04h 26m 3.51s Dec (J2000): -37d 15' 36.7" with an uncertainty of 2.4 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: 32194 SUBJECT: GRB 220611A: Swift-XRT refined Analysis DATE: 22/06/12 08:07:14 GMT FROM: Phil Evans at U of Leicester J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), J. D. Gropp (PSU), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), A.P. Beardmore (U. Leicester) and S.B. Cenko report on behalf of the Swift-XRT team: We have analysed 6.8 ks of XRT data for GRB 220611A (Cenko et al. GCN Circ. 32191), from 133 s to 40.2 ks after the BAT trigger. The data comprise 270 s in Windowed Timing (WT) mode (the first 10 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 Goad et al. (GCN Circ. 32192). The late-time light curve (from T0+5.3 ks) can be modelled with a power-law decay with a decay index of alpha=0.28 (+0.19, -0.21). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.31 (+/-0.06). The best-fitting absorption column is 1.04 (+0.13, -0.12) x 10^21 cm^-2, in excess of the Galactic value of 2.7 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.96 (+0.18, -0.08) and a best-fitting absorption column consistent with the Galactic value. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.2 x 10^-11 (3.4 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.7 (+1.8, -0.0) x 10^20 cm^-2 Galactic foreground: 2.7 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.96 (+0.18, -0.08) If the light curve continues to decay with a power-law decay index of 0.28, the count rate at T+24 hours will be 0.045 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.5 x 10^-12 (1.6 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01110090. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32195 SUBJECT: Swift GRB 220611A: Global MASTER-Net observations report DATE: 22/06/12 13:10:39 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, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (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), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University) MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB 220611A ( S. B. Cenko et al., GCN 32191) errorbox 55433 sec after notice time and 55505 sec after trigger time at 2022-06-12 09:26:56 UT, with upper limit up to 18.6 mag. The observations began at zenith distance = 74 deg. The sun altitude is -25.6 deg. The galactic latitude b = -44 deg., longitude l = 240 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2003639 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 55596 | MASTER-OAFA | C | 180 | 18.0 | 56606 | MASTER-OAFA | C | 180 | 18.1 | 56950 | MASTER-OAFA | C | 180 | 18.6 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32197 SUBJECT: GRB 220611A: Swift-BAT refined analysis DATE: 22/06/13 22:36:11 GMT FROM: Amy Lien at GSFC C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), S. B. Cenko (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-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 220611A (trigger #1110090) (Cenko et al., GCN Circ. 32191). The BAT ground-calculated position is RA, Dec = 66.505, -37.265 deg which is RA(J2000) = 04h 26m 01.2s Dec(J2000) = -37d 15' 54.2" with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 70%. The mask-weighted light curve shows a weak pulse that starts at ~T0 and ends at ~T+60 s. There might be a possible precursor emission (~ 5 sigma in the 15-350 keV image) from ~T-90 s to ~T-85 s. T90 (15-350 keV) is 57.00 +- 12.37 sec (estimated error including systematics). The time-averaged spectrum from T+0.52 to T+61.52 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.87 +- 0.29. The fluence in the 15-150 keV band is 6.7 +- 1.3 x 10^-7 erg/cm2. 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/1110090/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32201 SUBJECT: GRB 220611A: Swift/UVOT Upper Limits DATE: 22/06/15 16:59:08 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) and S. B. Cenko (GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 220611A 153 s after the BAT trigger (Cenko et al., GCN Circ. 32191). No optical afterglow consistent with the XRT position (Cenko et al. GCN Circ. 32191) 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 153 302 147 >19.5 u_FC 311 561 246 >19.1 white 153 926 245 >19.5 v 641 835 39 >17.0 b 566 759 39 >18.2 u 311 734 265 >19.1 w1 690 710 19 >17.7 m2 665 685 19 >17.9 w2 616 636 19 >18.7 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.033 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32203 SUBJECT: GRB 220611A: Gemini South Infrared Detection DATE: 22/06/16 18:57:55 GMT FROM: Brendan O'Connor at UMD B. O'Connor (UMD/GWU), E. Troja (Tor Vergata), S. Dichiara (PSU), on behalf of a larger collaboration: We performed target of opportunity observations of GRB 220611A (Cenko et al. GCN 32191) with the FLAMINGOS-2 spectrograph mounted on the Gemini-South telescope. Observations were carried out in the Ks filter with a total exposure of 260 s beginning at 3.7 d post-trigger. We detect a faint source within the XRT position (Goad et al. 32192) with magnitude Ks = 20.0+/-0.3 AB mag. The object is located at: RA, DEC = 04:26:03.56, -37:15:34.97 with an uncertainty of 0.5". This source is offset by 6" and 13", respectively, from two bright galaxies. The latter is located at redshift z~0.049 (Cenko et al. GCN 32191). Further observations are planned to determine whether the source is fading or if it is dominated by the contribution from an underlying host galaxy. We thank the staff of the Gemini Observatory, in particular Steve Margheim and Joan Font-Serra, for rapid scheduling of these observations. We thank Rodrigo Carrasco for carrying out the observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32208 SUBJECT: GRB 220611A: Gemini Ks counterpart detection DATE: 22/06/17 17:37:14 GMT FROM: Jillian Rastinejad at Northwestern Univ. J. Rastinejad (Northwestern), A. J. Levan (Radboud), D. B. Malesani (Radboud and DAWN/NBI), B. P. Gompertz (Birmingham), W. Fong, C. D. Kilpatrick (Northwestern) report on behalf of a larger collaboration: We observed the location of GRB 220611A (Cenko et al., GCN 32191) with the FLAMINGOS-2 instrument mounted on the Gemini-South 8-meter telescope on Cerro Pachon, Chile. At a mid-time of 2022 Jun 17.43 UT (~5.7 days post-burst), we obtained 48 x 11 s of K-band imaging at a median airmass of 2.15 and seeing of 1.1 arcsec. A K-band source is detected at the location reported by O'Connor et al. (GCN 32203). Based on calibration to 2MASS, we estimate a preliminary magnitude for the source of K_AB ~ 21.1 +/- 0.2 mag. Compared to the measurement reported by O'Connor et al. (K_AB = 20.0 +/- 0.3 mag), our value is indicative of fading, though we note that the strong, non-uniform background due to the nearby galaxy MCG-06-10-007 and the lack of a common set of calibrators prevent a definitive statement. Furthermore, the source is not detected in archival imaging from the VISTA Hemisphere Survey (VHS; Cross et al. 2012), from which we measure a limiting magnitude K_AB > 20.5 mag. If confirmed, the fading and the non-detection in the VHS images would indicate that this object is transient, thus likely associated with GRB 220611A. We also note that a faint optical source is visible in r-band Legacy Source imaging (Dey et al. 2019) at the location reported by O'Connor et al. (GCN 32203). We measure a preliminary magnitude of r_AB ~ 24.5 +/- 0.3 mag for this source (again, uncertain due to the strong, non-uniform background). At present, it is not possible to discern if this source is associated with the z = 0.049 galaxy, or is a fainter, background galaxy. Further observations are planned. We thank Jen Andrews, German Gimeno and Ricardo Salinas at Gemini for the rapid planning and execution of these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32217 SUBJECT: GRB220611A: Gemini Optical Afterglow Confirmation DATE: 22/06/18 13:24:01 GMT FROM: Eleonora Troja at GSFC B. O’Connor (UMD/GWU), E. Troja (U Tor Vergata/ASU) , S. Dichiara (PSU), and S. B. Cenko (NASA/GSFC) report on behalf of a larger collaboration: We carried out additional target of opportunity observations of GRB220611A (Cenko et al. GCN 32191) with the Gemini Multi Object Spectrograph (GMOS) mounted on the Gemini-South telescope. The observations began 5.7 d after the GRB trigger, and were performed in i-band for a total exposure of 540 s. We detect the source reported by O’Connor et al. (GCN 32203) with magnitude i~21 AB. This source is not detected in archival images from the Dark Energy Survey (Abbott et al. 2021), and is likely the GRB afterglow. We determine that the X-ray, optical, and infrared data (O’Connor et al. GCN 32203, Rastinejad et al. GCN 32208) can be modeled by a power-law with spectral index beta~1. Further observations are planned. We thank the Gemini staff for rapid scheduling of these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32228 SUBJECT: GRB 220611A: Continued Gemini Infrared Observations DATE: 22/06/19 21:39:00 GMT FROM: Brendan O'Connor at UMD B. O'Connor (UMD/GWU), E. Troja (U Tor Vergata/ASU), S. Dichiara (PSU), S. B. Cenko (UMD/GSFC), report on behalf of a larger collaboration: Additional target of opportunity observations of GRB 220611A (Cenko et al. GCN 32191) were carried out with the FLAMINGOS-2 spectrograph mounted on the Gemini-South telescope. Observations began at ~7.7 d in the Ks filter with a total exposure of 912 s. We detect the GRB afterglow (O’Connor et al. GCNs 32203 and 32217, Rastinejad et al. GCN 32208, Malesani et al. GCN 32222) with magnitude Ks~21.8 AB mag calibrated against stars in the 2MASS catalog. Compared to earlier Ks data (O’Connor et al. GCN 32203, Rastinejad et al. GCN 32208), the infrared counterpart’s temporal decay is consistent with the decay observed in X-rays by Swift/XRT. We thank the Gemini staff for rapid scheduling of these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32262 SUBJECT: GRB 220611A: X-ray afterglow Chandra sub-arcsecond localization DATE: 22/06/24 18:10:44 GMT FROM: Daniele B Malesani at Radboud U A. J. Levan (Radboud Univ.), D. B. Malesani (Radboud Univ. and DAWN/NBI), B. P. Gompertz (Birmingham) report on behalf of a larger collaboration: The Chandra X-ray observatory imaged the X-ray afterglow of GRB 220611A (Cenko et al., GCN 32191). Observations started on 2022 Jun 23.92 UT (12.15 days after the GRB), using the ACIS-S instrument, for a total exposure time of 15 ks. We detect a single object consistent with the Swift X-ray position (Goad et al., GCN 32192), with a total of ~30 source counts. Its coordinates are (J2000): RA = 04:26:03.57 Dec = -37:15:35.1 with an uncertainty of ~0.5". This position is consistent with the optical and near-infrared source reported by Gemini-S (O’Connor et al., GCN 32203, 32217; Rastinejad et al., GCN 32208) and VLT (Malesani et al., GCN 32222), as well as with the source seen in archival images from the Legacy Survey. This detection thus cements the nature of this object as the mutli-wavelength afterglow of GRB 220611A. We thank the Chandra director, Pat Slane, for awarding discretionary time to this project, and the observatory staff for rapidly planning and scheduling these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32595 SUBJECT: GRB 220611A: Host galaxy redshift from VLT/X-shooter DATE: 22/09/27 15:22:02 GMT FROM: Benjamin Schneider at CEA B. Schneider (CEA Paris-Saclay), D. B. Malesani (Radboud Univ. and DAWN/NBI), J. P. U. Fynbo (DAWN/NBI), K. Wiersema (Univ. Lancaster), L. Izzo (DARK/NBI), A. J. Levan (Radboud Univ.) report on behalf of the Stargate collaboration: We observed the location of GRB 220611A (Cenko et al., GCN 32191; Goad et al., GCN 32192; O’Connor et al., GCN 32203; Rastinejad et al., GCN 32208; Malesani et al., GCN 32222; Levan et al., GCN 32262) using the X-shooter spectrograph mounted on the ESO VLT UT3 (Melipal). Our target was the faint object visible in the archival optical images from the Legacy Survey, coincident with the optical and X-ray afterglow, first noticed by Rastinejad et al. (GCN 32208). The observation was performed on 2022 September 23 (104 days after the GRB) and consisted of 4x1200 s in the UVB and VIS arms and 8x600 s in the NIR arm. A filter was adopted to block part of the K band which in return increases the efficiency of the J and H bands, resulting in a wavelength coverage between 3000 to 21000 AA. In a preliminary reduction, we detect several strong emission lines that we identify as Lyman-alpha, [O II] 3729, [O III] 4959 and [O III] 5007 at a common redshift of z = 2.3608 +/- 0.0002. The [O II] 3726 and H-beta lines are affected by sky lines and are consequently not clearly detected. H-alpha falls outside the covered wavelength range. This result is supported by a VLT/MUSE spectrum obtained on 2022 August 24, covering the wavelength range 4800 to 9300 AA, which shows no emission nor absorption features, consistent with the measured redshift from X-shooter. The positional coincidence between our target and the optical and X-ray afterglow suggests a physical association. Furthermore, our spectra show that the archival counterpart is a star-forming galaxy, akin to a typical long GRB host. Our observations bring thus evidence that the GRB was not physically associated with the local, nearby galaxy MCG-06-10-007 at z = 0.049 (Cenko et al., GCN 32191), and their proximity is a chance coincidence. We acknowledge expert support from the ESO staff in Paranal, in particular Thomas Rivinius and Michael Abdul-Masih.