//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33271 SUBJECT: GRB 230205A: Swift detection of a burst DATE: 23/02/05 11:01:42 GMT FROM: Elena Ambrosi at INAF-IASF E. Ambrosi (INAF-IASFPA), A. D'Ai (INAF-IASFPA), A. Y. Lien (U Tampa), A. Melandri (INAF-OAB), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 10:29:51 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 230205A (trigger=1152764). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 202.072d, +46.684d which is RA(J2000) = 13h 28m 17s Dec(J2000) = +46d 41' 01" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Due to a telemetry gap, the BAT light curve before T+8s is not immediately available, and after that time shows no obvious variability. The BAT rate trigger was on a 3 s timescale, consistent with the lack of variation at later times. The XRT began observing the field at 10:31:40.0 UT, 108.8 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 202.07147, 46.72613 which is equivalent to: RA(J2000) = 13h 28m 17.15s Dec(J2000) = +46d 43' 34.1" with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 151 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 in excess of the Galactic value (2.09 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 1.2 (+0.71/-0.56) x 10^22 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 100 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 0.036. Burst Advocate for this burst is E. Ambrosi (elena.ambrosi AT inaf.it). 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: 33274 SUBJECT: GRB 230205A: BOOTES-5/JGT early optical upper limit DATE: 23/02/05 17:16:06 GMT FROM: Youdong HU at IAA-CSIC Y.-D. Hu, E. Fernandez-Garcia, A. J. Castro-Tirado, I. Perez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy (IAA-CSIC), D. Hiriart and W. H. Lee (UNAM), C. J. Perez del Pulgar (UMA) and I. Carrasco (SMA), I. H. Park (SKKU) on behalf of a larger collaboration, report: Following the detection of GRB 230205A by Swift (Ambrosi et al. GCNC 33271), the BOOTES-5/JGT 0.6m robotic telescope at Observatorio Astronomico Nacional in San Pedro Martir (Mexico) observed the GRB location starting on Feb. 5, 10:30:47 UT (~ 56 s after trigger). In the co-added image (20 x 60 s exposures in the clear filter), no optical afterglow is detected within the enhanced Swift/XRT error region (Ambrosi et al. GCNC 33271) down to 20.4 mag, which is consistent with the limit reported by UVOT (Ambrosi et al. GCNC 33271). We thank the staff at Observatorio Astronomico Nacional in San Pedro Martir for their excellent support. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33275 SUBJECT: GRB 230205A: Enhanced Swift-XRT position DATE: 23/02/05 17:46:40 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 2803 s of XRT Photon Counting mode data and 4 UVOT images for GRB 230205A, 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 = 202.07096, +46.72520 which is equivalent to: RA (J2000): 13h 28m 17.03s Dec (J2000): +46d 43' 30.7" with an uncertainty of 1.9 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: 33277 SUBJECT: GRB 230205A: Swift-XRT refined Analysis DATE: 23/02/05 21:29:13 GMT FROM: Phil Evans at U of Leicester K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), A. Tohuvavohu (U. Toronto), D.N. Burrows (PSU), J. D. Gropp (PSU), P.A. Evans (U. Leicester) and E. Ambrosi report on behalf of the Swift-XRT team: We have analysed 7.9 ks of XRT data for GRB 230205A (Ambrosi et al. GCN Circ. 33271), from 80 s to 30.1 ks after the BAT trigger. The data comprise 10 s in Windowed Timing (WT) mode (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. 33275). The late-time light curve (from T0+5.1 ks) can be modelled with a power-law decay with a decay index of alpha=0.85 (+0.29, -0.27). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.84 (+0.23, -0.22). The best-fitting absorption column is 6.0 (+1.6, -1.4) x 10^21 cm^-2, in excess of the Galactic value of 2.1 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.6 x 10^-11 (7.1 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 6.0 (+1.6, -1.4) x 10^21 cm^-2 Galactic foreground: 2.1 x 10^20 cm^-2 Excess significance: 6.8 sigma Photon index: 1.84 (+0.23, -0.22) If the light curve continues to decay with a power-law decay index of 0.85, the count rate at T+24 hours will be 5.6 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.6 x 10^-13 (4.0 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/01152764. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33280 SUBJECT: GRB 230205A: Swift-BAT refined analysis (T90 = 2.3 s) DATE: 23/02/06 04:14:03 GMT FROM: Amy Lien at GSFC T. Sakamoto (AGU), E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC), 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 230205A (trigger #1152764) (Ambrosi et al., GCN Circ. 33271). The BAT ground-calculated position is RA, Dec = 202.057, 46.686 deg which is RA(J2000) = 13h 28m 13.7s Dec(J2000) = +46d 41' 08.1" with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a short pulse that starts at ~T0, peaks at ~T+2 s, and ends at ~T+3 s. In addition, there may be some hint of extended emission that lasts till ~T+80 s. T90 (15-350 keV) is 2.30 +- 0.36 sec (estimated error including systematics). The time-averaged spectrum from T+0.32 to T+2.87 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.44 +- 0.29. The fluence in the 15-150 keV band is 1.6 +- 0.3 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+1.74 sec in the 15-150 keV band is 0.9 +- 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/1152764/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33282 SUBJECT: GRB 230205A: OHP/T193 optical observations DATE: 23/02/06 11:57:33 GMT FROM: Damien Turpin at NAOC (CAS) D. Turpin (CEA Paris-Saclay), C. Adami (LAM), E. Le Floc'h, D. Gotz, C. Plasse (CEA Paris-Saclay), B. Schneider (MIT),  S. D. Vergani, A. Saccardi (GEPI, Observatoire de Paris), S. Basa, M. Ferrari, A. Le Van Suu (LAM) report on behalf of a larger collaboration: We observed the field of the possible short GRB 230205A (Ambrosi et al., GCN 33271; Page et al., GCN 33277, Sakamoto et al., GCN 33280) using the T193cm telescope equipped with MISTRAL at Observatoire de Haute-Provence (France). Six exposures were obtained in the R-band (5x20s + 1x60s + 1x120s + 2x180s) under poor weather conditions from 2023 06 Feb. 03:37:06 UT to 2023 06 Feb 04:07:34 UT. In the combined last two frames (mid time ~17.57h after trigger), we do not detect the source and obtain the following upper limit: R > 20.95 mag (AB) The photometric calibration was performed using nearby stars from the PanSTARRS catalog. No further observations using the MISTRAL instrument mounted on the T193-OHP are planned. We acknowledge the excellent support from Observatoire de Haute Provence, in particular Stephane Favard, Jerome Schmitt. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33283 SUBJECT: GRB 230205A: SVOM/C-GFT optical upper limit DATE: 23/02/06 13:09:38 GMT FROM: Chao Wu at NAOC Chao Wu (NAOC), Zhe Kang (CHO), Liping Xin (NAOC), Xuhui Han (NAOC), Xiaomeng Lu (NAOC), Damien Turpin(CEA), Zhenwei Li (CHO)，Pinpin Zhang (NAOC)，Ruosong Zhang (NAOC)，Yulei Qiu (NAOC)，You Lv (CHO)，Jing Wang(GXU), Cordier Bertrand (CEA) and Jianyan Wei (NAOC) on behalf of SVOM GRB team We observed the burst GRB230205A (Ambrosi et al. GCN 33271) on 14:02:03 UT, Feb. 5th, 2023, about 3.5 hours after the Swift trigger with C-GFT (Chinese Ground Follow-up Telescope in SVOM mission) in System Test Mode (STM). C-GFT is located at Jilin (long.=126.33 deg, lat.= 43.8243778 deg), Changchun Observatory, National Astronomical Observatories, CAS. It has FOV of 1.5 deg X 1.5 deg with a 4k*4k CMOS detector mounted on the primary focus of 1.2-meter-aperure telescope. A series of g and r band images were obtained. The exposure time was 30 seconds for each frame. No optical afterglow was detected within the enhanced XRT error box (Goad et al., GCN 33275) down to a limit magnitude of 17.0 mag in each r-band single frame (in STM). The photometry was calibrated with nearby UCAC 4 catalogs. The upper limit is consistent with the limit reports (Ambrosi et al. GCN 33271; Hu et al., GCN 33274). More detailed analysis is continuing. We thank the observation assistant Bowen Li at Jilin observatory for their excellent support. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33286 SUBJECT: GRB 230205A: LCOGT Optical Upper Limits DATE: 23/02/06 16:21:38 GMT FROM: Robert Strausbaugh at University of Minnesota R. Strausbaugh (University of Minnesota), A. Cucchiara (NASA) report on behalf of a larger collaboration: We observed the GRB 230205A (Ambrosi et al., GCN 33271) field with the LCOGT 1-meter Sinistro instrument at the McDonald Observatory, TX, USA site, on February 6, from 11:51 to 12:23 UT (corresponding to 25.20 to 25.52 hours from the GRB trigger time) with the SDSS r and i filters. We performed a series of 3x300s exposures in each band. We do not detect a source in either band within the XRT enhanced error region (Goad et al., GCN 33275) consistent with other optical upper limits (Hu et al., GCN 33274; Turpin et al., GCN 33282; Wu et al., GCN 33283). The following magnitudes and upper limits are calculated using the PanSTARRS catalog as reference: r > 21.2 i > 20.8 These magnitudes are not corrected for galactic extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33289 SUBJECT: GRB 230205A: Swift/UVOT Upper Limits DATE: 23/02/06 20:44:18 GMT FROM: Mike Siegel at PSU/Swift MOC M.H. Siegel (PSU) and E/ Ambrosi (INAF-IASFPA) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 230205A 100 s after the BAT trigger (Ambrosi et al., GCN Circ. 33271). No optical afterglow consistent with the XRT position (Goad et al. GCN Circ. 33275) 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 100 250 147 >21.3 u_FC 258 508 246 >20.3 white 100 5198 526 >21.5 v 588 1581 117 >19.5 b 514 1680 117 >20.1 u 258 1481 343 >20.2 w1 638 657 19 >19.2 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.036 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33302 SUBJECT: GRB 230205A: possible host galaxy detection with the Schmidt - Asiago telescope DATE: 23/02/08 14:42:11 GMT FROM: Paolo D'Avanzo at INAF-OAB L. Tomasella (INAF-OAPd), P. D’Avanzo, (INAF-OAB), E. Cappellaro (INAF-OAPd) on behalf of a larger collaboration report: We observed the field of the possibly short GRB 230205A (Ambrosi et al, GCN Circ. 33271; Sakamoto et al., GCN Circ. 33280) with the Schmidt telescope of the INAF - Padova Astronomical Observatory located in Asiago (Italy). Observations were carried out in imaging mode with the r and i filters about 2.5 days after the burst T0. No clear afterglow candidate is detected within the enhanced XRT position (Goad et al., GCN Circ. 33275) down to the following magnitude limits: r > 21.2 mag, i > 21.0 mag (AB; 3sigma c.l.). In our i-band image we detect a source at the SW edge of the XRT error circle at the following position (J2000): RA = 13:28:16.87 Dec = +46:43:29.3 For this source we measure a magnitude of i = 21.1 +/- 0.3 (AB). We note that this source is detected also in archival SDSS and Pan-STARRS images. In the SDSS the source is named as SDSS J132816.81+464329.8 and is flagged as a galaxy with a photometric redshift of z = 0.484 +/- 0.090 and a magnitude i = 21.19 +/- 0.11 mag (AB; consistent with our measurement). This object is therefore a candidate host galaxy for GRB 230205A. As a further note, we report that the position of the X-ray afterglow of GRB 230205A lies at about 3.5 arminutes (in projection) to the galaxy NGC 5169 (whose luminosity distance is ~ 33 Mpc). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33307 SUBJECT: GRB 230205A: SUBARU HSC pre-imaging for host galaxy search DATE: 23/02/09 16:31:10 GMT FROM: Kuiyun Huang at CYCU Y. Urata, K.Y. Huang on behalf of a larger collaboration We processed pre-imaging data for the field of the possible short GRB 230205A (Ambrosi et al., GCN Circ. 33271; Sakamoto et al., GCN Circ. 33280) obtained by SUBRU Hyper-Suprime-Cam with i-band filter on June 6, 2019. No clear source is identified within the enhanced XRT position (Goad et al., GCN Circ. 33275). The host galaxy candidate suggested by Tomasella et al. (GCN Circ. 33302) is clearly detected. In addition to this source, there is a source with i = 22.1 +/- 0.1 at the NW edge of the XRT error circle at RA = 13:28:16.92 Dec = +46:43:32.73. The image is available at the following link. https://lh3.googleusercontent.com/VfQ2VhB3PtkCkwrfTVEKX0M0ARJ4bMKJk5g8vnVejx2Onx5CO5HamxaU6h34PDI1m0_MYmf3s-QSkacCSJYbEIMLV57-NkLBpnrVQCxVrMatuUvc4uf0euvRk9m65tiY7A=w1280 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33309 SUBJECT: GRB 230205A: 6 GHz VLA observations DATE: 23/02/09 22:07:28 GMT FROM: Genevieve Schroeder at Northwestern University G. Schroeder, J. C. Rastinejad, W. Fong, C. D. Kilpatrick, A. E. Nugent (Northwestern), E. Berger (Harvard), T. Laskar (Utah) report: "We observed the position of the possibly short GRB 230205A (Ambrosi et al, GCN 33271; Sakamoto et al., GCN 33280) with the Karl G. Jansky Very Large Array (VLA) under program 23A-296 (PI: Schroeder) beginning on 2023 February 8.25 UT (2.81 days post-burst) at a mean frequency of 6 GHz. We detect a radio source with a flux of ~40 microJy at the position: RA(J2000) = 13:28:16.838 Dec(J2000) = +46:43:32.87 with an uncertainty of ~0.5" in each coordinate. This position is on the outskirts of the XRT position (Goad et al. GCN 33275), on the NW edge. The radio source position is consistent with the position of the optical source reported by Urata et al. GCN 33307, although with a slight offset of ~0.85". If we assume this optical source is the host galaxy of GRB 230205A and the radio source is afterglow, we find a probability of chance coincidence of Pcc ~ 0.003 (Bloom et al. 2002). Alternatively, the detected radio emission could originate from the host. In contrast, the radio source is offset by ~3.6" from the center of the cataloged optical source (SDSS J132816.81+464329.8) mentioned by Tomasella et al. GCN 33302. If we instead assume that SDSS J132816.81+464329.8 is the host galaxy of GRB 230205A, we find Pcc ~ 0.02. Further observations are planned to determine the variability of the radio source. We thank the VLA staff for quickly approving and executing these observations." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33334 SUBJECT: GRB 230205A: Lowell Discovery Telescope Observations DATE: 23/02/17 00:43:14 GMT FROM: Brendan O'Connor at UMD B. O'Connor (UMD, GWU), E. Hammerstein (UMD), S.B. Cenko (UMD, NASA-GSFC), E. Troja (UTV, ASU), S.Dichiara (PSU), J. Durbak (UMD, NASA-GSFC), A. Kutyrev (UMD, NASA-GSFC), S. Veilleux (UMD), I. Andreoni (UMD, NASA-GSFC), and G. Srinivasaragavan (UMD): We observed the field of GRB 230205A (Ambrosi et al. GCN 33271; Sakamoto et al. GCN 33280) using the Large Monolithic Imager (LMI) on the 4.3m Lowell Discovery Telescope (LDT) at Happy Jack, AZ. We began observations on February 13, 2023 at 12:54:52 UT in r-band and i-band for 600 s each. The target was at airmass 1.1 with seeing ~2". We do not detect any source within the XRT enhanced position (Goad et al. GCN 33275) to depth r>23.8 AB mag. The host galaxy candidate (Tomasella et al. GCN 33302), hereafter S1, is clearly detected in both filters. We likewise detect the source (S2) reported by Urata et al. (GCN 33307). We measure the following magnitudes for S1 and S2: S1: r ~ 22.0 +/- 0.1 AB mag S1: i ~ 21.20 +/- 0.05 AB mag S2: r ~ 23.7 +/- 0.3 AB mag S2: i ~ 22.7 +/- 0.2 AB mag The magnitudes of S1 are consistent with the earlier report of Tomasella et al. (GCN 33302) and the SDSS catalog. For S2, we derive a slightly fainter i-band magnitude compared to Urata et al. (GCN 33307). However, as their images were obtained prior to the explosion, this is not an indication of fading. Thus, both these sources are candidate host galaxies to GRB 230205A (Schroeder et al. GCN 33309). Magnitudes are calibrated against the SDSS catalog and are not corrected for Galactic extinction. We thank the staff of the Lowell Discovery Telescope for assistance with these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33372 SUBJECT: GRB 230205A: VLA radio afterglow confirmation DATE: 23/02/23 21:04:20 GMT FROM: Genevieve Schroeder at Northwestern University G. Schroeder, (Northwestern), T. Laskar (Utah) report: "We re-observed the position of the possibly short GRB 230205A (Ambrosi et al., GCN 33271; Sakamoto et al., GCN 33280) with the Karl G. Jansky Very Large Array (VLA) under program 23A-296 (PI: Schroeder) beginning on 2023 February 22.52 UT (17.08 days post-burst) at a mean frequency of 6 GHz. The radio source detected in the previous VLA observation at 2.81 days (Schroeder et al. GCN 33309) has brightened significantly at 6 GHz, confirming this source as the radio afterglow of GRB 230205A. We report an updated radio position of: RA(J2000) = 13:28:16.837 Dec(J2000) = +46:43:33.13 With an uncertainty of ~0.1" in each coordinate. Further observations are planned. We thank the VLA staff for quickly approving and executing these observations."