August 2021 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 28622]GRB 210826A: Swift-XRT observations
by GCN Circulars 27 Aug '21

27 Aug '21

TITLE: GCN CIRCULAR NUMBER: 30725 SUBJECT: GRB 210826A: Swift-XRT observations DATE: 21/08/27 10:16:23 GMT FROM: Paolo D'Avanzo at INAF - OAB <paolo.davanzo(a)inaf.it> A. D'Ai (INAF-IASFPA), B. Sbarufatti (PSU), D.N. Burrows (PSU), J. D. Gropp (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAB), T. Sbarrato (INAF-OAB) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Fermi/LAT-detected burst GRB 210826A (Ohno et al. GCN Circ. 30721), for a total exposure time of 4.9 ks. The data were collected between T0+36.5 ks and T0+49.7 ks, and are entirely in Photon Counting (PC) mode. Eight uncatalogued X-ray sources have been detected, however none of them is above the RASS limit or shows definitive signs of fading. Therefore, at the present time we cannot identify which, if any, is the afterglow. We notice that one of the sources (Source 8) is consistent with a catalogued galaxy at redshift z = 0.05. Details of these sources are given below: Source 1: RA (J2000.0): 45.3361 = 03:01:20.66 Dec (J2000.0): -71.7072 = -71:42:25.8 Error: 8.7 arcsec (radius, 90% conf.) Count-rate: (1.46 [+0.80, -0.61])e-3 ct s^-1 Distance: 48 arcsec from Fermi/LAT position. Source 2: RA (J2000.0): 45.0955 = 03:00:22.93 Dec (J2000.0): -71.6531 = -71:39:11.1 Error: 5.0 arcsec (radius, 90% conf. [Enhanced position]) Count-rate: (3.06 [+1.16, -0.94])e-3 ct s^-1 Distance: 286 arcsec from Fermi/LAT position. Flux: (8.2 [+3.1, -2.5])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV) Source 4: RA (J2000.0): 45.1820 = 03:00:43.67 Dec (J2000.0): -71.5711 = -71:34:15.8 Error: 9.7 arcsec (radius, 90% conf.) Count-rate: (1.36 [+0.80, -0.59])e-3 ct s^-1 Distance: 483 arcsec from Fermi/LAT position. Flux: (8.2 [+4.8, -3.6])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV) This source is 10" away from the AGN candidate WISEA J030045.23-713422.8 (Assef et al., 2018, ApJS, 234, 23) Source 5: RA (J2000.0): 45.4777 = 03:01:54.65 Dec (J2000.0): -71.6539 = -71:39:13.9 Error: 8.4 arcsec (radius, 90% conf.) Count-rate: (3.7 [+1.3, -1.0])e-3 ct s^-1 Distance: 260 arcsec from Fermi/LAT position. Flux: (5.8 [+2.0, -1.6])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV) Source 6: RA (J2000.0): 45.1850 = 03:00:44.41 Dec (J2000.0): -71.7836 = -71:47:00.9 Error: 10.0 arcsec (radius, 90% conf.) Count-rate: (1.60 [+0.86, -0.65])e-3 ct s^-1 Distance: 327 arcsec from Fermi/LAT position. Flux: (4.2 [+2.2, -1.7])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV) Source 7: RA (J2000.0): 45.3683 = 03:01:28.39 Dec (J2000.0): -71.6617 = -71:39:42.1 Error: 10.3 arcsec (radius, 90% conf.) Count-rate: (1.54 [+0.84, -0.63])e-3 ct s^-1 Distance: 158 arcsec from Fermi/LAT position. This source is 6" away from the AGN candidate WISEA J030129.33-713938.6 (Assef et al., 2018, ApJS, 234, 23) Source 8: RA (J2000.0): 44.7903 = 02:59:9.68 Dec (J2000.0): -71.6112 = -71:36:40.2 Error: 9.3 arcsec (radius, 90% conf.) Count-rate: (1.11 [+0.78, -0.56])e-3 ct s^-1 Distance: 660 arcsec from Fermi/LAT position. This source is 9" away from the catalogued galaxy 2MASX J02591150-7136430 at redshift z = 0.05 Source 9: RA (J2000.0): 45.6834 = 03:02:44.02 Dec (J2000.0): -71.6574 = -71:39:26.7 Error: 8.8 arcsec (radius, 90% conf.) Count-rate: (2.16 [+1.02, -0.79])e-3 ct s^-1 Distance: 460 arcsec from Fermi/LAT position. Flux: (8.1 [+3.8, -3.0])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV) The results of the XRT-team automatic analysis of the tiled XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/xrt_products/TILED_GRB00101. This circular is an official product of the Swift-XRT team.

1 0

[vsnet-grb-info 28621]GRB 210827A: Fermi GBM Final Real-time Localization
by GCN Circulars 27 Aug '21

27 Aug '21

TITLE: GCN CIRCULAR NUMBER: 30724 SUBJECT: GRB 210827A: Fermi GBM Final Real-time Localization DATE: 21/08/27 10:09:47 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 09:59:24 UT on 27 Aug 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210827A (trigger 651751169.343218 / 210827416). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 138.3, Dec = 60.2 (J2000 degrees, equivalent to J2000 09h 13m, 60d 12'), with a statistical uncertainty of 20.2 degrees. The angle from the Fermi LAT boresight is 60.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210827416/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210827416/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210827416/…

1 0

[vsnet-grb-info 28620]GRB 210822A: CAHA 2.2m observations
by GCN Circulars 27 Aug '21

27 Aug '21

TITLE: GCN CIRCULAR NUMBER: 30723 SUBJECT: GRB 210822A: CAHA 2.2m observations DATE: 21/08/27 00:27:10 GMT FROM: Alexander Kann at IAA-CSIC <kann(a)iaa.es> D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), C. Thoene, M. Blazek, J. F. Agui Fernandez (all HETH/IAA-CSIC), A. Fernandez, I. Hermelo, and P. Martin (all CAHA) report: We observed the bright GRB 210822A (Swift detection: Page et al., GCN #30677; GECAM detection: Wang et al., GCN #30678; Fermi-LAT detection: Ohno et al., GCN #30687; AstroSat CZTI detection: Prasad et al., GCN #30693; Konus-Wind detection: Frederiks et al., GCN #30694; GRBAlpha detection: Ohno et al., GCN #30697) at a redshift of z = 1.736 (Zhu et al., GCN #30692) with CAFOS mounted on the 2.2m CAHA telescope at Calar Alto, Alemria, Spain. The first epoch was obtained under very inclement conditions (almost overcast), and one 60 s as well as four 90 s images were useful. The second epoch, two nights later, was obtained under significantly improved (but still not really good) conditions, and 31 x 30 s images were obtained. The optical afterglow (Page et al., GCN #30677; Zheng et al., GCN #30679; Butler et al., GCN #30680; Fu et al., GCN #30684; Zhu et al., GCN #30692; Romanov & Lane, GCN #30701; Nicuesa Guelbenzu et al., GCN #30703; Siegel et al., GCN #30710; Belkin et al., GCN #30712; Belkin et al., GCN #30714) is faintly detected in the first epoch, but not detected in the second epoch. Against three nearby Pan-STARRS comparison stars, we measure (AB magnitudes): i' = 18.56 +/- 0.14 mag at 0.43283 days after the GRB, and i' > 21.5 mag at 2.5206 mag after the GRB.

1 0

[vsnet-grb-info 28619]GRB 210824A: Swift-BAT refined analysis
by GCN Circulars 26 Aug '21

26 Aug '21

TITLE: GCN CIRCULAR NUMBER: 30722 SUBJECT: GRB 210824A: Swift-BAT refined analysis DATE: 21/08/26 19:38:20 GMT FROM: Hans Krimm at NSF/NASA-GSFC <hkrimm(a)nsf.gov> C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU) (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 210824A (trigger #1070157) (Page, et al., GCN Circ. 30700). The BAT ground-calculated position is RA, Dec = 232.115, 11.169 deg which is RA(J2000) = 15h 28m 27.5s Dec(J2000) = +11d 10' 09.9" with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 60%. The mask-weighted light curve shows a single broad pulse with some sub-structure. It begins around T-15 sec, peaks at the trigger time and decays to background by T+40 sec. We note that the light curve has a gap from T+110 sec to T+240 sec due to the burst going out of the field of view (for a pre-planned slew that started before the trigger had been fully processed) and then coming back into FOV when the pre-planned slew ended and the automated target slew had started. The burst appears to be over before this time. T90 (15-350 keV) is 37.55 +- 4.79 sec (estimated error including systematics). The time-averaged spectrum from T-13.70 to T+30.94 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.18 +- 0.11. The fluence in the 15-150 keV band is 1.7 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+1.02 sec in the 15-150 keV band is 1.3 +- 0.2 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/1070157/BA/

1 0

[vsnet-grb-info 28618]GRB 210826A: Fermi-LAT detection
by GCN Circulars 26 Aug '21

26 Aug '21

TITLE: GCN CIRCULAR NUMBER: 30721 SUBJECT: GRB 210826A: Fermi-LAT detection DATE: 21/08/26 19:15:46 GMT FROM: Masanori Ohno at Hiroshima U <ohno(a)astro.hiroshima-u.ac.jp> M. Ohno (Eotvos U./Hiroshima U.), M. Axelsson (KTH & Stockholm Univ.), F. Longo (University and INFN, Trieste), N. Omodei (Stanford Univ.) and F Dirirsa (LAPP, Annecy) report on behalf of the Fermi-LAT Collaboration: On August 26th, 2021, Fermi-LAT detected high-energy emission from GRB 210826A, which was also detected by Fermi GBM (trigger 651654110.161386 / 210826293; GCN 30716). The best LAT on-ground location is found to be RA, Dec 45.3, -71.7 (degrees, J2000) with an error radius of 0.2 deg (90% containment, statistical error only). This was 55 deg from the LAT boresight at the time of the GBM trigger: T0 = 07:01:45 UT. The data from the Fermi-LAT show a significant increase in the event rate after the trigger that is spatially correlated with the GBM emission with high significance. The photon flux above 100 MeV in the time interval 0-4000 s after the trigger is 9.3 (-/+ 3.8) e-07 ph/cm2/s. The estimated photon index above 100 MeV is -1.9 (-/+ 0.3). The highest-energy photon is a 7.7 GeV event which is observed ~2.6 ks after the trigger. A Swift ToO has been approved for this burst. The Fermi-LAT point of contact for this burst is Feraol Fana Dirirsa (dirirsa(a)lapp.in2p3.fr) The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.

1 0

[vsnet-grb-info 28617]Fermi GRB 210826A: Global MASTER-Net observations report
by GCN Circulars 26 Aug '21

26 Aug '21

TITLE: GCN CIRCULAR NUMBER: 30720 SUBJECT: Fermi GRB 210826A: Global MASTER-Net observations report DATE: 21/08/26 17:30:25 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 210826A ( Fermi GBM team, GCN 30716) errorbox 36801 sec after notice time and 36879 sec after trigger time at 2021-08-26 17:16:24 UT, with upper limit up to 17.8 mag. Observations started at twilight. The observations began at zenith distance = 71 deg. The sun altitude is -13.0 deg. The galactic latitude b = -35 deg., longitude l = 291 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1700544 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 36909 | 2021-08-26 17:16:24 | MASTER-SAAO | (05h 11m 37.00s , -76d 38m 26.5s) | C | 60 | 17.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.

1 0

[vsnet-grb-info 28616]GRB 210826A: Tiled Swift observations
by GCN Circulars 26 Aug '21

26 Aug '21

TITLE: GCN CIRCULAR NUMBER: 30719 SUBJECT: GRB 210826A: Tiled Swift observations DATE: 21/08/26 17:11:02 GMT FROM: Phil Evans at U of Leicester <pae9(a)leicester.ac.uk> P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a series of observations, tiled on the sky, of the Fermi/LAT GRB 210826A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00101 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the Fermi/LAT event is high: 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.

1 0

[vsnet-grb-info 28615]GRB 210824A: MITSuME Akeno optical upper limits
by GCN Circulars 26 Aug '21

26 Aug '21

TITLE: GCN CIRCULAR NUMBER: 30718 SUBJECT: GRB 210824A: MITSuME Akeno optical upper limits DATE: 21/08/26 09:48:44 GMT FROM: Masafumi Niwano at Tokyo Institute of Tech <niwano(a)hp.phys.titech.ac.jp> M. Niwano, K. L. Murata, R. Hosokawa, N. Ito, Y. Imai, H. Takamatsu, R. Noto, S. Sato, M. Takaku, R. Yamaguchi, Y. Yatsu, and N. Kawai (TokyoTech) report on behalf of the MITSuME collaboration: We observed the field of GRB 210824A (Fermi GBM team, GCN Circular #30699, K. L. Page et al. GCN Circular #30700, M.R. Goad et al. GCN Circular #30702, V. D'Elia et al. GCN Circular #30704, X. Liu et al. GCN Circular #30705, V. Lipunov et al. GCN Circular #30706, S. Lesage et al. GCN Circular #30707, Y.-D. Hu et al. GCN Circular #30708, V. Lipunov et al. GCN Circular #30709) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope Akeno. The observation with a series of 60 sec exposures started at 2021-08-25 10:20:44 UT (30.1 hours after Fermi trigger). We stacked the images with good conditions. We did not detect any uncatalogued sources within the XRT error region (V. D'Elia et al. GCN Circular #30706). We obtained the 5-sigma limits of the stacked images as follows. T0+[hour] MID-UT T-EXP[sec] 5-sigma limits ------------------------------------------------------------------------------------------------ 31.3 2021-08-25 12:29:20.71 4740 g'>18.6, Rc>19.0, Ic>18.3 ------------------------------------------------------------------------------------------------ T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used PS1 catalog for flux calibration. The magnitudes are expressed in the AB system. The images were processed in real-time through the MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1, Pages 4-24; https://github.com/MNiwano/Eclaire)

1 0

[vsnet-grb-info 28614]GRB 210826A: BALROG localization (Fermi Trigger 651654110 / GRB 210826293)
by GCN Circulars 26 Aug '21

26 Aug '21

TITLE: GCN CIRCULAR NUMBER: 30717 SUBJECT: GRB 210826A: BALROG localization (Fermi Trigger 651654110 / GRB 210826293) DATE: 21/08/26 07:41:33 GMT FROM: Jochen Greiner at MPE,Garching <jcg(a)mpe.mpg.de> B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report: The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger 651654110 at 07:01:45 on 26 Aug. 2021 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) = 84.3+/-5.4 deg Decl.(2000.0) = -75.6+/-0.7 deg We estimate an additional systematic error of 2 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB210826293/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB210826293/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB210826293/json

1 0

[vsnet-grb-info 28613]GRB 210826A: Fermi GBM Final Real-time Localization
by GCN Circulars 26 Aug '21

26 Aug '21

TITLE: GCN CIRCULAR NUMBER: 30716 SUBJECT: GRB 210826A: Fermi GBM Final Real-time Localization DATE: 21/08/26 07:12:03 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 07:01:45 UT on 26 Aug 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210826A (trigger 651654110.161386 / 210826293). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 64.6, Dec = -77.1 (J2000 degrees, equivalent to J2000 04h 18m, -77d 05'), with a statistical uncertainty of 2.1 degrees. The angle from the Fermi LAT boresight is 48.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210826293/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210826293/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210826293/…

1 0