//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31624 SUBJECT: IPN triangulation of GRB 220219B (consistent with ZTF22aabjpxh/AT2022cva) DATE: 22/02/21 18:38:56 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko, and T. Cline on behalf of the Konus-Wind 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 220219B has been detected by Konus-Wind (KW) and Swift (BAT), so far, at about 34045 s UT (09:27:25). The burst was outside the coded field of view of the BAT. We have triangulated it to a Konus-BAT annulus centered at RA(2000)=314.433 deg (20h 57m 44s) Dec(2000)=-14.987 deg (-14d 59' 15"), whose radius is 83.789 +/- 1.439 deg (3 sigma). This localization may be improved. The position of the optical transient ZTF22aabjpxh/AT2022cva (Ho et al., GCN Circ. 31619) is inside the annulus at 0.46 deg from its center line. The OT position is consistent with the Swift-BAT detection, Fermi-GBM non-detection, and the KW ecliptic latitude response. The positional and temporal coincidence of this burst with the OT supports the conclusion that the OT is the GRB counterpart. A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB220219_T34045/IPN The time history and spectrum will be given in forthcoming GCN Circulars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31634 SUBJECT: GRB 220219B: Swift ToO observations DATE: 22/02/22 17:10:13 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 Konus-Wind GRB 220219B. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021481 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 Konus-Wind 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: 31643 SUBJECT: ZTF22aabjpxh/AT2022cva (GRB 220219B): Mondy optical observations DATE: 22/02/23 22:36:04 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI, HSE), A. Pozanenko (IKI), N. Pankov (HSE), E. Klunko (ISTP) report on behalf of GRB IKI FuN: We observed ZTF22aabjpxh/AT2022cva discovered by ZTF (Ho et al., GCN 31619) with AZT-33IK telescope of Mondy observatory on 2022-02-21 and 2022-02-22. ZTF22aabjpxh/AT2022cva was observed also in optic (Kim et al., GCN 31628; Hu et al., GCN 31639) and in X-ray by NICER (Pasham et al., GCN 31635). ZTF22aabjpxh/AT2022cva is considered the likely afterglow of GRB 220219B (Ho et al., GCN 31619; Svinkin et al., GCN 31624). We clearly detect the SDSS galaxy at z=0.293 (Fremling et al., GCN 31629). Due to non-optimal seeing we could not discriminate the afterglow from the galaxy. We use aperture photometry and preliminary photometry of a source (afterglow+host galaxy) is following Date UT start JD Exp. Filter OT Err. UL(3sigma) (mid, days) (s) 2022-02-21 19:30:32 2.43966 30*120 R 19.19 0.03 22.8 2022-02-22 19:31:06 3.43936 29*120 R 19.34 0.03 22.8 The photometry is based on nearby SDSS DR12 stars id r R(Lupton) V(Lupton) J160337.10+311328.5 16.987 16.79 17.19 J160343.10+311452.9 18.700 18.51 18.90 Assuming the host galaxy has R = 19.7 we subtract a host galaxy flux from a flux of the source (afterglow+host galaxy) and estimated power law index of a light curve of the afterglow as -1.2, which is typical for a GRB afterglow. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31644 SUBJECT: GRB 220219B: Swift-XRT observations DATE: 22/02/24 11:18:42 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore (U. Leicester), M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), D.N. Burrows (PSU), J. D. Gropp (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of GRB 220219B (Svinkin et al., GCN Circ. 31624), collecting 3.5 ks of Photon Counting (PC) mode data between T0+322.5 ks and T0+369.3 ks. One uncatalogued X-ray source has been detected at a position consistent with the GRB optical afterglow candidate ZTF22aabjpxh/AT2022cva (Ho et al., GCN Circ. 31619). The X-ray source is below the RASS limit and shows no definitive signs of fading. Details of this source are given below: Source 1: RA (J2000.0): 240.91414 = 16:03:39.39 Dec (J2000.0): +31.23404 = +31:14:02.5 Error: 2.8 arcsec (radius, 90% conf. [Enhanced position]) Count-rate: 0.0250 [+0.0032, -0.0031] ct s^-1 Flux: (1.06 [+0.14, -0.13])e-12 erg cm^-2 s^-1 (observed, 0.3-10 keV) The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/ToO_GRBs/00021481. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31646 SUBJECT: Konus-Wind observation of GRB 220219B DATE: 22/02/25 05:54:26 GMT FROM: Anastasia Tsvetkova at Ioffe Institute A. Tsvetkova, D. Frederiks, A. Lysenko, A. Ridnaia, D. Svinkin, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 220219B (IPN triangulation: Svinkin et al., GCN 31624), consistent with the optical transient ZTF22aabjpxh/AT2022cva reported by ZTF (Ho et al., GCN 31619), triggered Konus-Wind at T0=34045.350 s UT (09:27:25.350). The burst light curve consists of two broad pulses: the first one lasts from ~T0-34 s to ~T0+13 s peaking at ~T0, the second pulse lasts from ~T0+18 s to ~T0+45 s peaking at ~T0+20 s, The emission is seen up to ~1 MeV. As observed by Konus-Wind, the burst had a fluence of the first pulse 1.21(-0.15,+0.16)x10^-5 erg/cm^2, a fluence of the whole burst 1.76(-0.14,+0.12)x10^-5 erg/cm^2, and a 64-ms peak energy flux, measured from T0-0.064 s, of 1.76(-0.27,+0.52)x10^-6 erg/cm^2/s (all in the 20 keV - 10 MeV energy range). Since the main fraction of the first pulse was detected before the trigger, its spectral analysis was performed using the KW 3-channel light curve data. Modelling its spectrum (measured from T0-33.723 s to T0+13.380 s) by the exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), yields alpha = -1.86(-0.09,+4.36) and Ep = 39(-24,+27) keV. Fitting the most intense part of the first pulse (measured from T0-1.340 s to T0+1.604 s) with by the exponential cutoff model yields alpha = -1.75(-0.20,+4.25) and Ep = 61(-46,+24) keV. The spectrum of the second emission pulse (from T0+16.640 s to T0+49.408 s) is well described by a simple power law (PL) with the photon PL index of 2.60(-0.10,+0.10) and chi2/dof = 69.5/61. Assuming the redshift z = 0.293 (Fremling et al., GCN 31629) and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014), we estimate the following burst rest-frame parameters: the isotropic energy release in the first pulse is Eiso = 2.75(-0.34,+0.36)x10^51 erg, the isotropic peak luminosity is Liso = 5.17(-0.79,+1.53)x10^50 erg/s; the rest-frame peak energy of the first pulse is Epiz = 50(-31,+35) keV; and the rest-frame peak energy of the 'peak' spectrum is Eppz = 79(-59,+31) keV. With these values, GRB 220219B is within 68% prediction bands for for both 'Amati' and 'Yonetoku' relations for the sample of >300 long KW GRBs with known redshifts (Tsvetkova et al., 2021, ApJ, 908, 83), see http://www.ioffe.ru/LEA/GRBs/GRB220219_T34045/GRB220219B_rest_frame.pdf The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB220219_T34045/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31683 SUBJECT: ZTF22aabjpxh/AT2022cva (GRB 220219B): continued optical observations, SN signature search DATE: 22/03/05 10:45:37 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI, HSE), A. Pozanenko (IKI), N. Pankov (HSE), E. Klunko (ISTP), I. Reva (FAI), V. Kim (FAI) report on behalf of GRB IKI FuN: We are continuing observations of ZTF22aabjpxh/AT2022cva discovered by ZTF (Ho et al., GCN 31619) with AZT-33IK telescope of Mondy observatory and Zeiss-1000 on 2022-02-21 between 2022-02-23 and 2022-03-04, i.e. upt 13.4 days after GRB 220219B trigger. ZTF22aabjpxh/AT2022cva was observed in optic (Kim et al., GCN 31628; Hu et al., GCN 31639) and in X-ray by NICER (Pasham et al., GCN 31635) and XRT/Swift (Beardmore et al., GCN 31644). ZTF22aabjpxh/AT2022cva is considered the likely afterglow of GRB 220219B (Ho et al., GCN 31619; Svinkin et al., GCN 31624; Tsvetkova et al., GCN 31646). We clearly detect the SDSS galaxy at z=0.293 (Fremling et al., GCN 31629). Due to non-optimal seeing we could not discriminate the afterglow from the galaxy. We use aperture photometry of a source (afterglow + host galaxy). Based on our preliminary photometry we plot a light curve of the source, see upper panel of the Figure in http://grb.rssi.ru/GRB220219B/GRB220219B_AT2022cva_LC.png To estimate power law index of the afterglow we fit our photometric data by a single power law + constant host galaxy flux. The host galaxy fit is R = 19.68+/-0.05 and PL index alpha = -1.75+/-0.4. The light curve of the afterglow after subtraction of a flux of the host is presented at bottom panel of the Figure in http://grb.rssi.ru/GRB220219B/GRB220219B_AT2022cva_LC.png Power Law index is broadly compatible with the index of -1.6 obtained in XRT observations up to ~8 days, see XRT light curve at https://www.swift.ac.uk/xrt_live_cat/00021481/ We may conclude the source ZTF22aabjpxh/AT2022cva is the optical afterglow of GRB 220219B. Since the redshift of GRB 220219B (ZTF22aabjpxh/AT2022cva) is z=0.293 (Fremling et al., GCN 31629) we are searching for a supernova signature. Based on the Figure referenced above we still don't see any conclusive evidence for the existence of SN. We urge further multicolour observations to confirm/search for SN associated with GRB 220219B. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31736 SUBJECT: ZTF22aabjpxh/AT2022cva (GRB 220219B): continued optical observations, possible photometric evidence of SN DATE: 22/03/11 02:03:18 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI, HSE), A. Pozanenko (IKI), E. Klunko (ISTP), A. Moskvitin (SAO RAS), R. Ya. Inasaridze (AbAO), N. Pankov (HSE), V. Kim (HSE, FAI), I. Reva (FAI), on behalf of GRB IKI FuN, and A. Rossi (INAF-OAS) report: We are continuing observations of ZTF22aabjpxh/AT2022cva discovered by ZTF (Ho et al., GCN 31619) with AZT-33IK telescope of Mondy observatory, AS-32 telescope of Abastumani observatory, and Zeiss-1000 telescope of SAO RAS between 2022-02-24 and 2022-03-09. ZTF22aabjpxh/AT2022cva was observed in optic (Kim et al., GCN 31628; Hu et al., GCN 31639; Belkin et al., GCNs 31643, 31683) and in X-ray by NICER (Pasham et al., GCN 31635) and XRT/Swift (Beardmore et al., GCN 31644). ZTF22aabjpxh/AT2022cva is considered an afterglow of GRB 220219B (Ho et al., GCN 31619; Svinkin et al., GCN 31624; Tsvetkova et al., GCN 31646; Belkin et al., GCN 31683). We clearly detect the SDSS galaxy at z=0.293 (Fremling et al., GCN 31629). Due to non-optimal seeing we could not discriminate the afterglow from the galaxy. We use aperture photometry of a source (afterglow + host galaxy). Based on our preliminary photometry we plot a light curve of the source, see an upper panel of the Figure in http://grb.rssi.ru/GRB220219B/GRB220219B_AT2022cva_LC.png To estimate power law index of the afterglow we fit our photometric data by a single power law + constant host galaxy flux between start of our observations and up to 13.4 days after GRB 220219B trigger. The host galaxy fit is R = 19.68+/-0.05 and PL index alpha = -1.75+/-0.4 (Belkin et al., GCN 31683). The light curve of the afterglow after subtraction of a flux of the host is presented at the bottom panel of the Figure in http://grb.rssi.ru/GRB220219B/GRB220219B_AT2022cva_LC.png Starting on ~15.5 days the light curve is rising above afterglow approximation by the single power law and we consider it as a possible evidence of rising supernova. We urge further spectroscopic and multicolour observations to confirm for SN associated with GRB 220219B. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31739 SUBJECT: ZTF22aabjpxh/AT2022cva (GRB 220219B): evidence of supernova in LBT spectra DATE: 22/03/11 14:41:55 GMT FROM: Andrea Rossi at INAF A. Rossi, E. Pian, F. Cusano, E. Maiorano, E. Palazzi (INAF-OAS) on behalf of the CIBO collaboration, and S. Belkin (IKI, HSE) report : We report the results of the spectroscopic follow-up observations of ZTF22aabjpxh/AT2022cva, the afterglow of GRB 220219B (Ho et al., GCN 31619; Kim  et al., GCN 31628; Hu et al., GCN 31639; Belkin et al., GCNs 31643, 31683; Pasham et al., GCN 31635; Beardmore et al., GCN 31644; Tsvetkova et al., GCN 31646) at z=0.293 (Fremling et al., GCN 31629). The optical spectra were obtained with the Multi-Object Double Spectrographs (MODS) instrument mounted on the 2x8.4-m LBT telescope (Mt. Graham, AZ, USA) at ~11 UT on 2021-03-07, ~16 days (i.e. ~12 rest-frame days) after the burst trigger. The spectra covers the wavelength range 3200-10000 AA, and we obtained a total of 6 exposures of 900s. The resulting spectrum has been corrected for Galactic extinction (A_V = 0.025 mag). The slit was place in order to cover both the host galaxy and the GRB position. In addition to the host spectra, a second trace is well visible in the 2D image of the spectrum although superimposed to the one of the host galaxy. Its low S/N extracted spectrum shows features similar to those exhibited by XRF-associated SN2006aj at a similar phase (Mazzali et al. 2006, Nature, 442, 1018). This confirms the bump observed by Belkin et al. (GCN 31736) as due to the emerging contribution of the SN. We acknowledge the excellent support from the LBTO, in particular B. Rothberg and J. Williams, and from the LBT-INAF, particularly E. Marini in obtaining these observations.