//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29511 SUBJECT: IPN triangulation of GRB 210212B (consistent with ZTF21aakruew/AT2021cwd) DATE: 21/02/15 18:35:45 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, S. Golenetskii, D. Frederiks, A. Ridnaia, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, K. Hurley, on behalf of the IPN, A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, and S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu on behalf of the Swift-BAT team, report: The long-duration GRB 210212B has been detected by Konus-Wind, in the waiting mode, INTEGRAL (SPI-ACS), and Swift (BAT), so far, at about 9477 s UT (02:37:57). The burst was likely outside the coded field of view of the BAT. We have triangulated it to a preliminary, error box whose coordinates are: --------------------------------- RA(2000), deg Dec(2000), deg --------------------------------- Corners: 159.26 +24.95 100.54 +38.07 96.30 +19.08 163.83 +2.39 --------------------------------- This box may be improved. The optical transient ZTF21aakruew/AT2021cwd (Yao et al., GCN Circ. 29508) is inside the box, lending support to the association of the transient and the burst. A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB210212_T09477/IPN/ The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29512 SUBJECT: GRB 210212B (TF21aakruew/AT2021cwd): Assy optical observations DATE: 21/02/16 13:44:36 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Pozanenko (IKI), S. Belkin (IKI), V. Kim (FAI, Pulkovo Observatory), Y. Aimuratov (FAI), M. Krugov (FAI), N.Pankov (HSE) report on behalf of GRB IKI FuN We observed the optical transient of ZTF21aakruew/AT2021cwd (Yao et al., GCN 29508) which is probably an afterglow of GRB 210212B (Svinkin et al., GCN 29511) with AZT-20 telescope of Assy-Turgen observatory starting on 2021-02-15 (UT) 17:33:23. The optical transient is marginally detected in a stacked image in r'-filter. Preliminary photometry of the object is following Date UT start t-T0 Filter Exp. OT S/N Err. UL(3sigma) (mid, days) (s) 2021-02-15 17:33:23 3.64231 r' 59*60 23.8 2.5 0.5 23.6 The photometry is based on nearby SDSS-DR12 stars RA DEC r dr 10:24:36.66048 +11:35:29.6088 18.206 0.008 10:24:34.08528 +11:36:05.0220 17.486 0.006 10:24:47.98080 +11:38:11.0832 15.153 0.003 The midtime value (t-T0) given in the table above was counted from GRB trigger of 2021-02-12 (UT) 02:37:57 (Svinkin et al., GCN 29511). The power-law index of the light curve (alpha ~ 1.7) is consistent with an afterglow after jet break. The light curve can be found in http://grb.rssi.ru/GRB210212B/GRB210212B_LC.png //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29513 SUBJECT: GRB 210212B: Swift ToO observations DATE: 21/02/16 15:07:04 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a ToO observation of the IPN GRB 210212B. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021423 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the IPN event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29514 SUBJECT: Konus-Wind detection of GRB 210212B / ZTF21aakruew DATE: 21/02/16 16:15:34 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 210212B (ZTF OT detection: Yao et al., GCN Circ. 29508; IPN triangulation: Svinkin et al., GCN Circ. 29511) was detected by Konus-Wind (KW) in the waiting mode. The burst light curve shows a single emission episode which starts at about T0=9479 s UT (02:37:59) and has the total duration of ~48 s. The K-W light curve of this burst is available at http://www.ioffe.ru/LEA/GRBs/GRB210212_T09477/ As observed by Konus-Wind, the burst had a fluence of 8.7(-1.1,+1.7)x10^-6 erg/cm2 and a 2.944-s peak flux, measured from ~T0, of 6.7(-1.6,+4.8)x10^-7 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The K-W 3-channel time-integrated spectrum (from T0 to T0+48 s) is well described by a cutoff power-law model with alpha = -1.24(-0.23,+0.33) and Ep = 208(-46,+84) keV. All the quoted errors are estimated at the 1 sigma confidence level. All the presented results are preliminary.