//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31609 SUBJECT: GRB 220219A: Fermi GBM Final Real-time Localization DATE: 22/02/19 11:32:48 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 11:21:34 UT on 19 Feb 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220219A (trigger 666962499.096148 / 220219473). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 41.6, Dec = 9.0 (J2000 degrees, equivalent to J2000 02h 46m, 9d 00'), with a statistical uncertainty of 1.0 degrees. The angle from the Fermi LAT boresight is 79.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220219473/quicklook/glg_skymap_all_bn220219473.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220219473/quicklook/glg_healpix_all_bn220219473.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220219473/quicklook/glg_lc_medres34_bn220219473.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31610 SUBJECT: GRB 220219A: BALROG localization (Fermi Trigger / GRB 220219473) DATE: 22/02/19 12:16:28 GMT FROM: Jochen Greiner at MPE,Garching F. Kunzweiler, B. Biltzinger, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report: The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger at 11:21:34 on 19 Feb. 2022 were automatically fitted for spectrum and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427; Berlato et al. 2019, ApJ 873, 60). The best-fit position (1 sigma statistical errors) is: RA(2000.0) = 37.8+/-0.7 deg Decl.(2000.0) = 17.0+/-1.1 deg We estimate an additional systematic error of 2 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB220219473/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB220219473/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB220219473/json //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31611 SUBJECT: GRB 220219A: AGILE/MCAL detection DATE: 22/02/19 14:20:46 GMT FROM: Alessandro Ursi at INAF/IAPS A. Ursi (INAF/IAPS), M. Pilia (INAF/OA-Cagliari), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Argan, M. Cardillo, C. Casentini, Y. Evangelista, L. Foffano, E. Menegoni, G. Piano (INAF/IAPS), F. Lucarelli, C. Pittori, 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), 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 Mini-CALorimeter (MCAL) detected the GRB 220219A T0 = 2022-02-19 11:21:35.02 +/- 0.01 s (UTC), reported by Fermi GBM (GCN #31609). The event lasted about 9.5 s and released a total number of 7450 counts in the MCAL detector (in the 0.4-100 MeV energy range), above an average background rate of 597 Hz. The MCAL light curve can be found at http://www.agilescienceapp.it/notices/077070_GRB_MCAL_572354495.021853.png . The time-integrated spectrum of the burst, from T0-3.0 s to T0+6.5 s, can be fitted in the energy range 0.4-10 MeV with a power-law with ph.ind. = -2.83 (-0.24,+0.28), resulting in a reduced chi-squared of 0.78 (48 d.o.f.) and a fluence of 1.26e-05 erg/cm^2 (90% confidence level), in the same energy range. The burst is also clearly visible in the AGILE scientific ratemeters of the MiniCALorimeter (MCAL; 0.4-100 MeV), and AntiCoincidence (AC; 50-200 keV) detectors. The event lasted about 9 s and it released a total number of 13810 counts in the MCAL detector (above a background rate of 1210 Hz), and 33110 counts in the AC detector (above a background rate of 3370 Hz). The AGILE ratemeter light curves can be found at http://www.agilescienceapp.it/notices/GRB220219A_AGILE_RM.png . At the T0, the event was 140 deg off-axis. The AGILE-MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the energy range 0.4-100 MeV. Additional analysis of AGILE data is in progress. Automatic MCAL GRB alert Notices can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31621 SUBJECT: IPN triangulation of GRB 220219A DATE: 22/02/21 16:12:59 GMT FROM: Dmitry Svinkin at Ioffe Institute A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars-Odyssey team, D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, A. Goldstein, M. S. Briggs, and C. Wilson-Hodge on behalf of the Fermi GBM team, and W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report: The long-duration GRB 220219A (Fermi-GBM detection: The Fermi GBM team, GCN Circ. 31609; BALROG localization: Kunzweiler et al., GCN Circ. 31610; AGILE-MCAL detection: Ursi et al., GCN Circ. 31611) has been detected by Fermi (GBM trigger 666962499), AGILE (MCAL), Konus-Wind, and Mars-Odyssey (HEND), so far, at about 40894 s UT (11:21:34). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 42.243 (02h 48m 58s) +10.588 (+10d 35' 17") Corners: 43.946 (02h 55m 47s) +6.216 ( +6d 12' 57") 39.857 (02h 39m 26s) +17.180 (+17d 10' 49") 39.457 (02h 37m 50s) +18.548 (+18d 32' 54") 43.844 (02h 55m 23s) +6.598 ( +6d 35' 54") --------------------------------------------- The error box area is 2243 sq. arcmin, and its maximum dimension is 13.1 deg (the minimum one is 3.1 arcmin). The Sun distance was 72 deg. This box may be improved. The IPN localization is consistent with, but reduces the area of, the Fermi GBM Final Real-time position (GCN Circ. 31609) and BALROG (GCN 31610) localizations. A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB220219_T40894/IPN/ The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31622 SUBJECT: Konus-Wind observation of GRB 220219A DATE: 22/02/21 17:12:32 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 220219A (Fermi-GBM detection: The Fermi GBM team, GCN 31609; AGILE/MCAL detection: Ursi at al., GCN31611; IPN triangulation: Kozyrev et al., GCN 31621) triggered Konus-Wind at T0=40894.695 s UT (11:21:34.695). The burst light curve shows a multi-peaked structure which starts at ~T0-0.4 s and has a total duration of~76.6 s. The emission is seen up to ~15 MeV. As observed by Konus-Wind, the burst had a fluence of 5.75(-2.01,+1.80)x10^-5 erg/cm2, and a 64-ms peak energy flux, measured from T0+3.792 s, of 1.08(-0.21,+0.21)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum of the burst (measured from T0 to T0+80.384 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -1.01(-0.39,+0.52), the high energy photon index beta = -1.86(-1.11,+0.20), the peak energy Ep = 379(-155,+830) keV, chi2 = 93/97 dof. The spectrum near the peak count rate (measured from T0 to T0+6.656 s) is best fit in the 20 keV - 15 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with  alpha = -1.03(-0.10,+0.11), and Ep = 480(-57,+73) keV (chi2 = 97/98 dof). Fitting by the GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.29 (chi2 = 96.1/97 dof). The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB220219_T40894/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// 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.