GRB210112A

This page lists all entries on GRB210112A in GRBweb

Summary IPN Swift GCN 29289 GCN 29290 GCN 29292 GCN 29293 GCN 29295 GCN 29296 GCN 29297 GCN 29300 GCN 29301 GCN 29302 GCN 29303 GCN 29315 GCN 29319 GCN 29326 GCN 29333 GCN 29456

Summary table
Variable Value Source
T0 1:37:03 UTC GCN_circulars,Swift Det
ra 219.0062° Swift
decl 33.0543° Swift
pos_error 6.47e-05° Swift
T90 107.6 s Swift
T90_start 1:37:03 UTC Swift
fluence 2.33e-05 erg/cm² Swift
redshift 2.0000 GCN_circulars,Optical
T100 107.6 s
GBM_located False
mjd 59226.067395833335 GCN_circulars,Swift Det
IPN table
GRB_name GRB210112A
ra 219.0000°
decl 33.0667°
pos_error 5.00e-02°
Swift table
GRB_name GRB210112A
t_trigger 1:37:03 UTC
ra 219.0062°
decl 33.0543°
pos_error 6.47e-05°
T90 107.6 s
fluence 2.33e-05 erg/cm²
GCN 29289 table
GRB_name GRB210112A
GCN_number 29289
Detection_method Swift Det
t_trigger 1:37:03 UTC
ra 218.9990°
decl 33.0700°
Circular_text TITLE: GCN CIRCULAR NUMBER: 29289 SUBJECT: GRB 210112A: Swift detection of a burst with an optical counterpart DATE: 21/01/12 01:51:00 GMT FROM: David Palmer at LANL E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC), A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC), J. A. Kennea (PSU), N. J. Klingler (PSU), S. Laha (GSFC/UMBC/CRESST), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 01:37:03 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 210112A (trigger=1016881). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 218.999, +33.070 which is RA(J2000) = 14h 36m 00s Dec(J2000) = +33d 04' 13" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multiple peaks with the larger peak at T+70 sec and duration of ~150 sec. The peak count rate was ~20800 counts/sec (15-350 keV), at ~68 sec after the trigger. The XRT began observing the field at 01:38:18.0 UT, 74.2 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 219.0044, 33.0566 which is equivalent to: RA(J2000) = 14h 36m 1.06s Dec(J2000) = +33d 03' 23.8" with an uncertainty of 5.0 arcseconds (radius, 90% containment). This location is 50 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 0.1 s image was 7.10e-08 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 82 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 14:36:01.45 = 219.00606 DEC(J2000) = +33:03:15.4 = 33.05428 with a 90%-confidence error radius of about 0.66 arc sec. This position is 9.8 arc sec. from the center of the XRT error circle. The estimated magnitude is 19.52 with a 1-sigma error of about 0.16. No correction has been made for the expected extinction corresponding to E(B-V) of 0.014. 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/)
GCN 29290 table
GRB_name GRB210112A
GCN_number 29290
Detection_method Swift-XRT Det
ra 219.0060°
decl 33.0541°
Circular_text TITLE: GCN CIRCULAR NUMBER: 29290 SUBJECT: GRB 210112A: Enhanced Swift-XRT position DATE: 21/01/12 04:17:47 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 579 s of XRT Photon Counting mode data and 1 UVOT images for GRB 210112A, 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 = 219.00603, +33.05415 which is equivalent to: RA (J2000): 14h 36m 1.45s Dec (J2000): +33d 03' 15.0" 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.
GCN 29292 table
GRB_name GRB210112A
GCN_number 29292
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 29292 SUBJECT: GRB 210112A: Kitab a optical upper limit DATE: 21/01/12 11:19:27 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Novichonok (Petrozavodsk State University, KIAM), S. Belkin (IKI), A. Pozanenko (IKI), Sh. Ehgamberdiev (UBAI) report on behalf of GRB IKI FuN: We observed the field of GRB 210112A (Ambrosi et al., GCN 29289) with Kitab-ISON RC-36 telescope starting on 2021-01-12 (UT) 01:54:30, i.e. 447 seconds after trigger in Clear filter. We do not detect the afterglow candidate (Ambrosi et al., GCN 29289) within enhanced Swift-XRT position (Goad et al., GCN 29290). Preliminary photometry of the field is following Date, UT start, t-T0, Exp., Filter, OT, Err., UL (mid, days) 2021-01-12 01:54:30 0.01541 11*30 CR n/d n/d 18.5 The photometry is based on nearby USNO-B1.0 stars USNO-B1.0_id R2 1231-0260671 14:35:00.70080 +33:06:09.4428 14.32 1229-0281658 14:34:57.67344 +32:58:13.0800 14.75 At 01:37:03 UT
GCN 29293 table
GRB_name GRB210112A
GCN_number 29293
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 29293 SUBJECT: GRB 210112A: AGILE detection DATE: 21/01/12 12:30:09 GMT FROM: Alessandro Ursi at INAF/IAPS A. Ursi, M. Cardillo (INAF/IAPS), C. Pittori (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Argan, C. Casentini, Y. Evangelista, G. Piano (INAF/IAPS), F. Lucarelli, F. Verrecchia (SSDC, and INAF/OAR), A. Bulgarelli, 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), F. Longo (Univ. Trieste and INFN Trieste), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team: The AGILE satellite detected GRB 210112A, reported by Swift (GCNs #29289, #29290), at T0 = 2021-01-12 01:37:58 (UT). The event is clearly visible in the scientific ratemeters of the SuperAGILE (SA; 18-60 keV), MiniCALorimeter (MCAL; 0.4-100 MeV), and AntiCoincidence (AC; 50-200 keV) detectors. The burst lasted about 25 s and released 1120 counts in the SA detector (above a background rate of 60 Hz), 25140 counts in the MCAL detector (above a background rate of 1250 Hz), and 71500 counts in the AC detector (above a background rate of 3570 Hz). The AGILE ratemeters light curves can be found at: http://www.agilescienceapp.it/notices/GRB210112A_AGILE_RM.png . Additional analysis of AGILE data is in progress.
GCN 29295 table
GRB_name GRB210112A
GCN_number 29295
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 29295 SUBJECT: GRB 210112A: Swift-XRT refined Analysis DATE: 21/01/12 17:20:18 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), B. Sbarufatti (PSU), D.N. Burrows (PSU), J. D. Gropp (PSU), K.L. Page (U. Leicester) and E. Ambrosi report on behalf of the Swift-XRT team: We have analysed 8.5 ks of XRT data for GRB 210112A (Ambrosi et al. GCN Circ. 29289), from 77 s to 46.0 ks after the BAT trigger. The data comprise 859 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN Circ. 29290). The late-time light curve (from T0+6.4 ks) can be modelled with a power-law decay with a decay index of alpha=1.36 (+/-0.06). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.56 (+/-0.03). The best-fitting absorption column is 2.34 (+/-0.14) x 10^21 cm^-2, in excess of the Galactic value of 9.5 x 10^19 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.01 (+0.10, -0.09) and a best-fitting absorption column of 2.8 (+/-0.4) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (5.1 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.8 (+/-0.4) x 10^21 cm^-2 Galactic foreground: 9.5 x 10^19 cm^-2 Excess significance: 12.3 sigma Photon index: 2.01 (+0.10, -0.09) If the light curve continues to decay with a power-law decay index of 1.36, the count rate at T+24 hours will be 0.046 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.7 x 10^-12 (2.3 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/01016881. This circular is an official product of the Swift-XRT team.
GCN 29296 table
GRB_name GRB210112A
GCN_number 29296
Detection_method Optical
redshift 2.0000
Circular_text TITLE: GCN CIRCULAR NUMBER: 29296 SUBJECT: GRB 210112A: OSN Reddened Afterglow Detection DATE: 21/01/12 19:28:59 GMT FROM: Alexander Kann at IAA-CSIC D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), C. C. Thoene (HETH), M. Blazek, J. F. Agui Fernandez (both HETH/IAA-CSIC), and A. Sota (IAA-CSIC) report: We observed the optical afterglow of GRB 210112A (Swfit detection: Ambrosi et al., GCN #29289; AGILE Detection: Ursi et al., GCN #29293) with the 1.5m telescope of the Observatorio de Sierra Nevada (OSN), Granada, Spain. We obtained 12 x 90 s exposures in B, Rc, Ic and 11 x 90 s in V, between 2021-01-12 04:03:22.52 and 2021-01-12 05:21:34.99 UT. The afterglow is detected In the combined image of each band. At 0.12587 days after the GRB, we measure Rc = 22.41 +/- 0.12 mag (AB mag, vs. a several nearby SDSS stars converted to Rc following the Lupton transformations, then transformed back to AB mag). A preliminary analysis of all data reveals peculiar colors, the Rc - Ic color is large, whereas the colors between B, V, and Rc are quite flat. There is no source detected in either SDSS or PanSTARRS at the afterglow position, so this is probably not due to influence of the host galaxy. However, we are able to fit this SED with a large (A_V > 1 mag) amount of Milky-Way like dust at a redshift of z ~ 2 and an intrinsic slope in agreement with the one derived from X-ray observations. Such high extinction would be in line with the significant excess column density seen in the XRT observations (Evans et al., GCN #29295).
GCN 29297 table
GRB_name GRB210112A
GCN_number 29297
Detection_method Swift-BAT Det
ra 219.0050°
decl 33.0580°
Circular_text TITLE: GCN CIRCULAR NUMBER: 29297 SUBJECT: GRB 210112A: Swift-BAT refined analysis DATE: 21/01/13 01:45:13 GMT FROM: Amy Lien at GSFC M. Stamatikos (OSU), E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), T. N. Ukwatta (LANL) (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 210112A (trigger #1016881) (Ambrosi et al., GCN Circ. 29289). The BAT ground-calculated position is RA, Dec = 219.005, 33.058 deg which is RA(J2000) = 14h 36m 01.3s Dec(J2000) = +33d 03' 30.4" with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 89%. The mask-weighted light curve shows a multi-peaked structure that starts at ~T-10 s and ends at ~T+220 s. The three main peaks occur at ~T+1 s, ~T+70 s, and ~T+105 s, respectively, and the one at ~T+70 s is the largest peak. T90 (15-350 keV) is 107.60 +- 13.02 sec (estimated error including systematics). The time-averaged spectrum from T-10.44 to T+218.47 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.45 +- 0.03. The fluence in the 15-150 keV band is 2.33 +- 0.03 x 10^-5 erg/cm2. The 1-sec peak photon flux measured from T+68.86 sec in the 15-150 keV band is 20.5 +- 0.6 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/1016881/BA/
GCN 29300 table
GRB_name GRB210112A
GCN_number 29300
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 29300 SUBJECT: GRB 210112A: OSN second epoch, decay DATE: 21/01/13 19:50:01 GMT FROM: Alexander Kann at IAA-CSIC D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), C. C. Thoene (HETH), M. Blazek, J. F. Agui Fernandez (both HETH/IAA-CSIC), and A. Sota (IAA-CSIC) report: We observed again the optical afterglow of GRB 210112A (Swfit detection: Ambrosi et al., GCN #29289; AGILE Detection: Ursi et al., GCN #29293) with the 1.5m telescope of the Observatorio de Sierra Nevada (OSN), Granada, Spain. We obtained 3 x 450 s exposures in B, V, Rc each, and 8 x 150 s in Ic, between 2021-01-13 04:29:28.99 and 2021-01-13 05:55:34.35 UT. The afterglow is now only detected in the combined Ic-band image. Together with the observations of the day before (Kann et al., GCN #29296), we measure (against the same SDSS comparison stars as before, in Vega mags): Ic = 20.65 +/- 0.075 mag at 0.12587 days. Ic = 22.57 +/- 0.217 mag at 1.12739 days. This implies a decay index of alpha ~ 0.8.
GCN 29301 table
GRB_name GRB210112A
GCN_number 29301
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 29301 SUBJECT: GRB 210112A: 1.3m DFOT Optical upper limit DATE: 21/01/13 19:54:17 GMT FROM: Rahul Gupta at ARIES, India Rahul Gupta (ARIES), Amit Kumar (ARIES), Dimple (ARIES), Ankur Ghosh (ARIES), Krishan Chand (ARIES), Amar Aryan (ARIES), Shashi B. Pandey (ARIES), and Kuntal Misra (ARIES) report: We observed the filed of Swift and AGILE detected GRB 210112A (Ambrosi et al., GCN 29289; and Ursi et al., GCN 29293) with 1.3m Devasthal Fast Optical Telescope (DFOT) located at Devasthal observatory of Aryabhatta Research Institute of Observational Sciences (ARIES), India. The observations were started on 2021-01-13 at 00:06:18 UT i.e. ~ 22.49 hours after the BAT trigger. We have taken multiple frames having an exposure time of 120 s in the R filter. We do not detect the optical afterglow candidate (Ambrosi et al., GCN 29289; and Kann et al., GCN 29296) within enhanced Swift-XRT position (Goad et al., GCN 29290). We obtain the following 3-sigma upper limits in the stacked image. Date Start_UT T_start-T0 (hrs) Filter Exp time (s) Limiting Magnitude ============================================================ 2021-01-13 00:18:18 22.69 R 120*12 > 22.0 The magnitude 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 catalogue. This circular may be cited.
GCN 29302 table
GRB_name GRB210112A
GCN_number 29302
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 29302 SUBJECT: GRB 210112A: Mondy optical observations DATE: 21/01/13 20:28:18 GMT FROM: Alexei Pozanenko at IKI, Moscow N. Pankov (HSE), A. Pozanenko (IKI), E. Klunko (ISTP), S. Belkin (IKI) report on behalf of GRB IKI FuN: We observed the field of GRB 210112A (Ambrosi et al., GCN 29289; Ursi et al., GCN #9293) with AZT-33IK telescope of Sayan observatory (Mondy) starting on 2021-01-12 (UT) 20:41:40. The optical afterglow (Ambrosi et al., GCN 29289; Kann et al., GCNs 29296, 29300) is not detected in stacked image in R-filter. The non detection of the afterlow is consistent with other non-detections in R-filter (Novichonok et al., GCN 29292; Gupta et al., GCN 29301). Preliminary photometry of the optical transient in a combined image is following Date UT start t-T0 Filter Exp. OT Err. UL(3sigma) (mid, days) (s) 2021-01-12 20:41:40 0.80738 R 18*120 n/d n/d 22.4 The photometry is based on the nearby USNO-B1.0 stars.
GCN 29303 table
GRB_name GRB210112A
GCN_number 29303
Detection_method Swift-UVOT Det
ra 219.0062°
decl 33.0543°
Circular_text TITLE: GCN CIRCULAR NUMBER: 29303 SUBJECT: GRB 210112A: Swift/UVOT Detection DATE: 21/01/15 03:50:43 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) and Ambrosi (INAF-IASFPA) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 210112A 83 s after the BAT trigger (Ambrosi et al., GCN Circ. 29289). A source consistent with the XRT position (Goad et al. GCN Circ. 29290) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 14:36:01.49 = 219.00619 (deg.) Dec (J2000) = +33:03:15.3 = 33.05424 (deg.) with an estimated uncertainty of 0.50 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 83 233 147 19.54 +/- 0.10 v 626 1419 97 >18.5 b 551 1517 97 >19.1 u 296 1493 304 >20.2 w1 675 1468 78 >19.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.014 in the direction of the burst (Schlegel et al. 1998).
GCN 29315 table
GRB_name GRB210112A
GCN_number 29315
Detection_method Konus-Wind Det
t_trigger 1:38:06.553 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 29315 SUBJECT: Konus-Wind detection of GRB 210112A DATE: 21/01/17 23:28:52 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, S. Golenetskii, D. Frederiks, M. Ulanov, A. Tsvetkova, A. Lysenko, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 210112A (Swift-BAT detection: Ambrosi et al., GCN Circ. 29289; AGILE detection: Ursi et al., GCN Circ. 29293) triggered Konus-Wind at T0=5886.553 s UT (01:38:06.553). The burst light curve shows a multipeaked structure which starts at ~T0-73 s and has a total duration of ~143 s. The emission is seen up to ~5 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB210112_T05886 As observed by Konus-Wind, the burst had a fluence of 6.72(-0.65,+0.72)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+7.856 s, of 1.02(-0.18,+0.19)x10^-5 erg/cm2/s (both in the 20 keV - 16 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+68.608 s) is best fit in the 20 keV - 16 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.96(-0.08,+0.08), the high energy photon index beta = -2.71(-0.53,+0.25), the peak energy Ep = 214(-16,+18) keV (chi2 = 87/97 dof). The spectrum near the maximum count rate (measured from T0+7.168 s to T0+9.216 s) is best fit in the 20 keV - 16 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.85(-0.12,+0.13), the high energy photon index beta = -2.67(-0.57,+0.27), the peak energy Ep = 219(-25,+28) keV (chi2 = 38/65 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN 29319 table
GRB_name GRB210112A
GCN_number 29319
Detection_method Swift Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 29319 SUBJECT: GRB 210112A: Deep CAHA 2.2m detection DATE: 21/01/18 15:53:55 GMT FROM: Alexander Kann at IAA-CSIC D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), C. C. Thoene (HETH), M. Blazek, J. F. Agui Fernandez (both HETH/IAA-CSIC), and J. I. Vico Linares (CAHA) report: We observed the afterglow position (Ambrosi et al., GCN #29289) of the bright Swift GRB 210112A (Swift detection: Ambrosi et al., GCN #29289; AGILE detection: Ursi et al., GCN #29293; Konus-Wind detection: Svinkin et al., GCN #29315) with CAFOS at the 2.2m telescope at Calar Alto, Almeria, Spain, in the Ic band. We obtained 10 x 360 s exposures, centered at 5.1696 days after the GRB, under good conditions but mediocre seeing. The afterglow (Kann et al., GCNs #29296,29300; Siegel et al., GCN #29303) is faintly detected. We measure Ic = 23.69 +/- 0.24 mag. (AB mag, vs. a several nearby SDSS stars converted to Ic following the Lupton transformations, then transformed back to AB mag). This magnitude lies slightly above the extrapolation of the decay found during the first two epochs (Kann et al., GCN #29300) and may indicate an underlying host galaxy. Indeed we also see another faint, possibly extended source about 2" to the East, at RA (J2000) = 14:36:01.453, Dec. (J2000) = +33:03:13.40, which may be the host galaxy or a system interacting with it. However, the rough redshift estimate of z ~ 2 (Kann et al., GCN #29296) would imply this must be a very luminous system, or a foreground interloper.
GCN 29326 table
GRB_name GRB210112A
GCN_number 29326
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 29326 SUBJECT: GRB 210112A: Insight-HXMT/HE detection DATE: 21/01/19 11:22:13 GMT FROM: Y Q Zhang at IHEP C. Zheng, C. Cai, J. C. Liu, Q. Luo, S. Xiao, W. C. Xue, Q. B. Yi, Y. Q. Zhang, Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, X. Y. Song, S. L. Xiong, C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team: At 2021-01-12T01:38:13.400 (T0), Insight-HXMT/HE detected GRB 210112A (trigger ID: HEB210112068) in a routine search of the data, which also triggered Swift/BAT (E. Ambrosi (INAF-IASFPA) et al. ,GCN #29289). The Insight-HXMT/HE light curve mainly consists of multiple pulses with a duration (T90) of 12.27 s measured from T0+0.91 s. The 1-ms peak rate, measured from T0+7.63 s, is 2134 cnts/sec. The total counts from this burst is 213416252 counts. URL_LC: http://twiki.ihep.ac.cn/pub/HXMT/GRBList/HEB210112068_lc.jpg All measurements above are made with the CsI detectors operating in the regular mode with the energy range of about 80-800 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://www.hxmt.org.
GCN 29333 table
GRB_name GRB210112A
GCN_number 29333
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 29333 SUBJECT: GRB 210112A: 3.6m DOT optical detection DATE: 21/01/20 06:14:31 GMT FROM: Dimple Panchal at ARIES, India Dimple (ARIES), K. Misra (ARIES), A. Ghosh (ARIES), R. Gupta (ARIES), A. Kumar (ARIES), S.B. Pandey (ARIES) report: We carried out the follow-up observations of GRB 210112A (Ambrosi et al. GCN #29289) with Aries Devasthal Faint Object Spectrograph and Camera (ADFOSC) mounted on the 3.6m Devasthal Optical Telescope (DOT) at Devasthal observatory of Aryabhatta Research Institute of observational sciencES (ARIES), India. The observations started on 2021-01-13 at 23:59:18 UT in i-band (sdss). We observed a series of 6 images with an exposure time of 300 seconds each. We detect the afterglow at 1.933 days after the burst, reported by Ambrosi et al. GCN #29289; Ursi et al. GCN #29293; Kann et al. GCNs #29296,29300; Siegel et al. GCN #29303, in i-band with a magnitude of 23.19 +- 0.166 (AB mag), calibrated with the nearby PanSTARRS field. Our results are consistent with the power-law decay index of 0.8 reported by Kann et al. #29296. The magnitude is not corrected for Galactic extinction in the direction of the burst.
GCN 29456 table
GRB_name GRB210112A
GCN_number 29456
Detection_method correction
Circular_text TITLE: GCN CIRCULAR NUMBER: 29456 SUBJECT: GRB 210112A: LBT host detection and correction to GCN 29319 (CAHA observations) DATE: 21/02/10 15:12:35 GMT FROM: Alexander Kann at IAA-CSIC A. Rossi (INAF-OAS), on behalf of the CIBO collaboration, and D. A. Kann (HETH/IAA-CSIC) report: We observed the field of GRB210112A (Ambrosi et al., GCN #29289; Ursi et al., GCN #29293; Svinkin et al., GCN #29315) simultaneously in the r' and z' bands with the LBC imager mounted on the Large Binocular Telescope (LBT, Mt. Graham, AZ, USA). We obtained 20 min of imaging on 2021-02-05, 24.3 days after the burst trigger. Observations were performed under mediocre seeing conditions and reached a depth of r' ~ 26 mag. At the position of the afterglow (Ambrosi et al., GCN #29289), we clearly detect the host galaxy in both filters and we measure the following AB magnitudes: r' = 23.96 +/- 0.15 mag, z' = 23.38 +/- 0.15 mag. calibrated against SDSS field stars. Therefore, we confirm that the flattening observed by Kann et al. (GCN #29319) was due to the host component. However, we do not see the faint object detected by Kann et al. at RA, Dec. = 14:36:01.453, +33:03:13.40 (J2000). We have investigated the CAHA and OSN (Kann et al., GCN 29296) images and found that the source detected by Kann et al., GCN 29319, which should have been "South" of the afterglow position, not "East", is the actual afterglow (with the fainter, northern extension possibly stemming from image distortion or a slight mismatch when co-adding frames), the offset stemming from a small arcsecond-scale astrometry mismatch. For the afterglow position, we measure Ic = 23.52 ± 0.19 mag (AB), replacing the value given in GCN #29319. We estimate the underlying host to be Ic ~ 23.7 mag (AB) from the LBT photometry. Correlating the OSN image with the LBT image, we find an afterglow position of RA, Dec. = 14:36:01.492 +33:03:14.945 (J2000), with errors of 0".2 in each coordinate, calibrated against Gaia DR2, in good agreement with the UVOT position (Ambrosi et al., GCN #29289). In the LBT image, we furthermore detect a second, fainter, but probably also extended source just 2" north-north-east of the host (at RA, Dec. =14:36:01.54 +33:03:18.7; J2000) with r' = 24.5 ± 0.2 mag. It is unclear if this likely galaxy is related to the host galaxy. We acknowledge the excellent support from the LBTO and LBT-INAF staff, particularly B. Rothberg and D. Paris, in obtaining these observations.