//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32345 SUBJECT: GRB 220708B: Swift/BAT-GUANO arcminute localization DATE: 22/07/08 10:11:30 GMT FROM: Aaron Tohuvavohu at U Toronto Aaron Tohuvavohu (U Toronto), James DeLaunay (UAlabama), Gayathri Raman (PSU), Jamie A. Kennea (PSU), report: Swift/BAT did not localize GRB 220708B onboard (T0: 2022-07-08T02:06:67 UTC, CALET trig #1341281218). The CALET notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 90 seconds of BAT event-mode data from [-45,+45] seconds around the time of the burst. All the requested event mode data was delivered to the ground. The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu, arXiv:2111.01769), detects the burst in a 4.096 s analysis time bin with a sqrt(TS) of 41.4. The duration of the burst as seen by BAT is ~7 seconds. A confident arcminute localization is found with DeltaLLHOut of 150 and a DeltaLLHPeak of 68. See Section 9.1 and Figure 20 in the NITRATES paper for brief descriptions and interpretations of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut. The BAT position is RA, Dec = 248.652, 36.338 deg which is RA(J2000) = 16h 34m 36.48s Dec(J2000) = +36d 20′ 16.8″ with an estimated uncertainty of 5 arcmin. XRT and UVOT follow-up has been requested Results of follow-up observations will be reported in future circulars. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32346 SUBJECT: GRB 220708B: Swift ToO observations DATE: 22/07/08 11:50:47 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 Swift/BAT-GUANO GRB 220708B. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021508 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 Swift/BAT-GUANO 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: 32350 SUBJECT: GRB 220708B: Swift-XRT afterglow detection DATE: 22/07/08 14:27:31 GMT FROM: Phil Evans at U of Leicester J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), B. Sbarufatti (PSU), D.N. Burrows (PSU), J. D. Gropp (PSU) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Swift/BAT-GUANO-detected burst GRB 220708B, collecting 1.7 ks of Photon Counting (PC) mode data between T0+35.1 ks and T0+36.8 ks. An uncatalogued X-ray source is detected and is above the RASS 3-sigma upper limit at this position, and is therefore likely the GRB afterglow. The position of this source is RA, Dec=248.5790, +36.3478 which is equivalent to: RA (J2000): 16:34:18.97 Dec(J2000): +36:20:52.0 with an uncertainty of 4.0 arcsec (radius, 90% confidence). This position is 3.6 arcmin from the Swift/BAT-GUANO position. The light curve is consistent with a constant source of mean count rate 6.5e-02 ct/sec. A power-law fit gives an index of 0.0 (+0.0, -3.3). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.3 (+0.6, -0.5). The best-fitting absorption column is 3.2 (+2.2, -1.7) x 10^21 cm^-2, in excess of the Galactic value of 1.4 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 3.2 x 10^-11 (5.7 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3.2 (+2.2, -1.7) x 10^21 cm^-2 Galactic foreground: 1.4 x 10^20 cm^-2 Excess significance: 2.9 sigma Photon index: 2.3 (+0.6, -0.5) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00021508. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021508. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32355 SUBJECT: GRB 220708B: Nanshan/NEXT optical upper limits DATE: 22/07/09 03:18:20 GMT FROM: Dong Xu at NAOC/CAS S.Q. Jiang (NAOC), Z.P. Zhu (NAOC,HUST), S.Y. Fu , X. Liu, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report: We observed the field of GRB 220708B detected by Swift/BAT-GUANO (Tohuvavohu et al., GCN 32345) using the NEXT-0.6m telescope located at Nanshan, Xinjiang, China. We obtained 10x200 s frames in the Sloan r-band and 9x200 s frames in Sloan z-band, starting at 19:15:57.859 UT on 2022-07-08,i.e.,17.15 hr after the BAT trigger. No optical source is detected in our stacked images at the XRT afterglow position (Osborne et al., GCN 32350), with upper limits as follows: T_mid-T0 (hr) Filter Upper limit(3-sigma) 17.42 r >21.60 17.96 z >19.54 calibrated with the nearby PanSTARRS field and not corrected for Galactic extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32356 SUBJECT: GRB 220708B: CALET Gamma-Ray Burst Monitor detection DATE: 22/07/09 04:25:21 GMT FROM: Yuta Kawakubo at Louisiana State U./CALET K. Kobayashi (Waseda U), A. Yoshida, T. Sakamoto, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka (ICRR), S. Torii, Y. Akaike (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration: The long GRB 220708B (Swift/BAT-GUANO arcminute localization: Tohuvavohu et al., GCN Circ. 32345) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 02:06:55.120 UTC on 8 July 2022 (http://cgbm.calet.jp/cgbm_trigger/flight/1341281218/index.html). The burst signal was seen by all CGBM detectors. The burst light curve shows a single pulse which starts at T+2.6 sec, peaks at T+4.8 sec, and ends at T+6.5 sec. The T90 and T50 durations measured by the SGM data are 3.4 +/- 0.3 sec and 1.4 +/- 0.2 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1341281218/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32358 SUBJECT: Konus-Wind detection of GRB 220708B DATE: 22/07/09 16:57:15 GMT FROM: Dmitry Frederiks at Ioffe Institute D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long GRB 220708B (Swift/BAT-GUANO arcminute localization: Tohuvavohu et al., GCN Circ 32345; CALET-CGBM detection: Kobayashi et al., GCN Circ 32356) triggered Konus-Wind (KW) at T0=7620.140 s UT (02:07:00.140). The burst light curve shows two separated emission episodes. The first episode (reported in GCNs 32345, 32356) starts at ~T0-1 s and has a duration of ~4 s. The second, much longer episode starts at ~T0-380 s and lasts to ~T0+450 s. The emission is seen up to ~2 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB220708_T07620/ As observed by Konus-Wind, the burst had a total fluence of (1.23 ± 0.44)x10^-5 erg/cm^2 and a 64-ms peak energy flux, measured from T0 + 0.832 s, of (2.03 ± 0.39)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the first episode (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 15 MeV range by a power law with exponential cutoff (CPL) model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.68(-0.22,+0.44) and Ep = 90(-9,+11) keV (chi2 = 77/97 dof). Fitting this spectrum by a Band function yields the same values of alpha and Ep, and an upper limit on the high energy photon index beta of -2.8 (chi2 = 76/96 dof). The fluence in this time interval is (2.8 ± 0.5)E-06 erg/cm^2. The time-averaged spectrum of the second episode (measured from T0+377.088 to T0+450.816 s) is best fit in the 20 keV - 15 MeV range by a CPL model with alpha = -1.48(-0.31,+0.42) and Ep = 146(-45,+66) keV (chi2 = 90/98 dof). A Band function fits the spectrum equally well with alpha = -1.20 (-0.56,+0.57), beta = -2.29(-7.71, + 0.34), and Ep = 107 (-32, +68) keV (chi2 = 90/97 dof). The fluence in this time interval is (9.5 ± 3.9)E-06 erg/cm^2. All the quoted errors are estimated at the 90% confidence level. All the presented results are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32359 SUBJECT: Konus-Wind detection of GRB 220708B (Correction to GCN 32358) DATE: 22/07/10 16:26:21 GMT FROM: Dmitry Frederiks at Ioffe Institute D. Frederiks, on behalf of the Konus-Wind team: The correct start time of the second episode of GRB 220708B reported in the KW GCN 32358 is T0+380 s. We apologize for the typo and thank Jean-Luc Atteia for pointing this out. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32360 SUBJECT: GRB 220708B: T193-OHP optical upper limit DATE: 22/07/10 20:54:34 GMT FROM: Damien Turpin at NAOC (CAS) D. Turpin (CEA), C. Adami (LAM), B. Schneider, E. Le Floch (CEA), S. Basa (LAM) report on behalf of a larger collaboration: We observed the field of GRB 220708B (Tohuvavohu et al. GCN 32345, Kobayashi et al. GCN 32356, Frederiks et al. GCN 32358) using the T193cm telescope at Observatoire de Haute-Provence (France) equipped with the MISTRAL spectro-imager. Six exposures (6x600s) were obtained in the r band using the bleu MISTRAL set-up from 2022 08 Jul 20:55:39 UT to 2022 08 Jul 22:14:27 UT (mid time ~19.5h after trigger). In the combined frame, we do not detect any source within the 4 arcsec error circle of the XRT position (Osborne et al. GCN 32350) down to the following 3-sigma limit: r > 22.3 mag (AB) The photometric calibration was performed using nearby stars from the PanSTARRS catalog. The magnitude is not corrected for Galactic extinction and it is consistent with the non-detections reported by Jiang et al. (GCN 32355). We express our deepest thanks to the Observatoire de Haute-Provence for its support, in particular to Stphane Favard and Jrme Schmitt. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32363 SUBJECT: GRB 220708B: GIT optical upper limits DATE: 22/07/11 11:45:05 GMT FROM: Varun Bhalerao at Indian Inst of Tech V. Swain (IITB), H. Kumar (IITB), K. Angail (IAO), V. Bhalerao (IITB), G. C. Anupama (IIA), S. Barway (IIA) report on behalf of the GIT team: We observed GRB 220708B detected by Swift (Tohuvavohu et al., GCN 32345; Evans et at., GCN 32350), CALET GBM (Kawakubo et al., GCN 32356) and Konus-Wind (Frederiks et al., GCN 32358), with the 0.7m GROWTH-India Telescope (GIT). The observations started at 21:04:33 UT on 2022-07-08, 18.96 hours after the Swift trigger. We obtained multiple 300-sec exposures in the g’, r' and i’ filters. We did not detect any new source in our stacked images within the 4 arcsec radius circle around R.A.= 16h 34m 18.97s, Dec.= +36d 20' 52.0” (Osborne et al. GCN #32350). The obtained upper limits follow as: ------------------------------------------------------------------- JD (mid) | T_mid-T0(hrs) | Exposure (sec) | Filter | Lim_mag (5-sigma) | ------------------------------------------------------------------- 2459769.38578312 | 19.14 | 4 x 300 (stacked) | g' | > 21.03 | 2459769.39333163 | 19.32 | 4 x 300 (stacked) | r' | > 20.99 | 2459769.41415129 | 19.82 | 4 x 300 (stacked) | i' | > 19.83 | ------------------------------------------------------------------- These upper limits are consistent with Jiang et al.(GCN #32355), Turpin et al.(GCN #32360). The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction. The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.