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

[vsnet-grb-info 28660] GRB 210904A: Fermi GBM Final Real-time Localization
by GCN Circulars 04 Sep '21

04 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30763 SUBJECT: GRB 210904A: Fermi GBM Final Real-time Localization DATE: 21/09/04 20:58:06 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 SHORT GRB At 20:47:39 UT on 4 Sep 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210904A (trigger 652481264.630844 / 210904866). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 121.1, Dec = -44.0 (J2000 degrees, equivalent to J2000 08h 04m, -44d 00'), with a statistical uncertainty of 9.2 degrees. The angle from the Fermi LAT boresight is 104.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210904866/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210904866/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210904866/…

1 0

[vsnet-grb-info 28659] Swift GRB210903.59: Global MASTER-Net observations report
by GCN Circulars 04 Sep '21

04 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30762 SUBJECT: Swift GRB210903.59: Global MASTER-Net observations report DATE: 21/09/04 14:06:08 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-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB210903.59 (trigger No 1071768,19h 58m 08.69s , +34d 58m 31.8s, R=0.0013) errorbox 10573 sec after notice time and 10763 sec after trigger time at 2021-09-03 17:06:18 UT, with upper limit up to 18.4 mag. Observations started at twilight. The observations began at zenith distance = 21 deg. The sun altitude is -9.6 deg. MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB210903.59 errorbox 17837 sec after notice time and 18026 sec after trigger time at 2021-09-03 19:07:21 UT, with upper limit up to 18.0 mag. The observations began at zenith distance = 13 deg. The sun altitude is -32.4 deg. MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB210903.59 errorbox 34110 sec after notice time and 34300 sec after trigger time at 2021-09-03 23:38:35 UT, with upper limit up to 16.6 mag. The observations began at zenith distance = 72 deg. The sun altitude is -17.6 deg. The galactic latitude b = 3 deg., longitude l = 71 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1708701 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 10854 | MASTER-Tavrida | C | 180 | 16.0 | 11468 | MASTER-Tavrida | C | 180 | 17.4 | 12664 | MASTER-Tavrida | C | 180 | 17.9 | 14017 | MASTER-Tavrida | C | 180 | 18.0 | 14475 | MASTER-Tavrida | C | 180 | 18.2 | 16334 | MASTER-Tavrida | C | 180 | 16.6 | 18117 | MASTER-Kislovodsk | C | 180 | 16.8 | 18117 | MASTER-Kislovodsk | C | 180 | 17.0 | 18263 | MASTER-Tavrida | C | 180 | 18.2 | 20001 | MASTER-Kislovodsk | C | 180 | 18.0 | 20001 | MASTER-Kislovodsk | C | 180 | 17.7 | 20140 | MASTER-Tavrida | C | 180 | 18.4 | 21805 | MASTER-Kislovodsk | C | 180 | 17.7 | 21805 | MASTER-Kislovodsk | C | 180 | 18.0 | 22143 | MASTER-Tavrida | C | 180 | 17.1 | 23689 | MASTER-Kislovodsk | C | 180 | 17.5 | 23689 | MASTER-Kislovodsk | C | 180 | 17.8 | 24010 | MASTER-Tavrida | C | 180 | 18.2 | 25493 | MASTER-Kislovodsk | C | 180 | 17.2 | 25494 | MASTER-Kislovodsk | C | 180 | 17.6 | 25959 | MASTER-Tavrida | C | 180 | 18.2 | 27299 | MASTER-Kislovodsk | C | 180 | 16.6 | 27299 | MASTER-Kislovodsk | C | 180 | 17.4 | 27952 | MASTER-Tavrida | C | 180 | 18.1 | 29103 | MASTER-Kislovodsk | C | 180 | 16.0 | 29103 | MASTER-Kislovodsk | C | 180 | 17.0 | 29947 | MASTER-Tavrida | C | 180 | 18.1 | 31940 | MASTER-Tavrida | C | 180 | 18.2 | 33748 | MASTER-Tavrida | C | 180 | 17.8 | 34390 | MASTER-OAFA | C | 180 | 16.0 | 35611 | MASTER-Tavrida | C | 180 | 17.6 | 36466 | MASTER-OAFA | C | 180 | 16.5 | 37511 | MASTER-Tavrida | C | 180 | 17.9 | 37844 | MASTER-Kislovodsk | C | 180 | 12.6 | 38341 | MASTER-OAFA | C | 180 | 16.6 | 39331 | MASTER-Tavrida | C | 180 | 17.2 | 40219 | MASTER-OAFA | C | 180 | 16.6 | 41730 | MASTER-Tavrida | C | 180 | 17.2 | 42215 | MASTER-OAFA | C | 180 | 16.4 | 51950 | MASTER-OAFA | C | 180 | 15.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.

1 0

[vsnet-grb-info 28658] Swift GRB210903.58: Global MASTER-Net observations report
by GCN Circulars 04 Sep '21

04 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30761 SUBJECT: Swift GRB210903.58: Global MASTER-Net observations report DATE: 21/09/04 13:56:08 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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB210903.58 (trigger No 1071765,12h 24m 38.93s , -62d 40m 53.8s, R=0.0016) errorbox 34282 sec after notice time and 34506 sec after trigger time at 2021-09-03 23:31:41 UT, with upper limit up to 17.3 mag. Observations started at twilight. The observations began at zenith distance = 59 deg. The sun altitude is -16.1 deg. MASTER-SAAO robotic telescope located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB210903.58 errorbox 41864 sec after notice time and 42088 sec after trigger time at 2021-09-04 01:38:04 UT, with upper limit up to 15.9 mag. The observations began at zenith distance = 84 deg. The sun altitude is -41.4 deg. The galactic latitude b = -0 deg., longitude l = 300 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1708696 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 34596 | MASTER-OAFA | C | 180 | 16.8 | 34796 | MASTER-OAFA | C | 180 | 17.3 | 36393 | MASTER-OAFA | C | 180 | 17.3 | 36831 | MASTER-OAFA | C | 180 | 16.6 | 38319 | MASTER-OAFA | C | 180 | 16.5 | 38749 | MASTER-OAFA | C | 180 | 16.9 | 40189 | MASTER-OAFA | C | 180 | 16.6 | 40622 | MASTER-OAFA | C | 180 | 16.9 | 42179 | MASTER-SAAO | C | 180 | 15.9 | 42378 | MASTER-SAAO | C | 180 | 15.6 | 42623 | MASTER-OAFA | C | 180 | 17.0 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.

1 0

[vsnet-grb-info 28657] Swift GRB210903.58: Global MASTER-Net observations report
by GCN Circulars 04 Sep '21

04 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30760 SUBJECT: Swift GRB210903.58: Global MASTER-Net observations report DATE: 21/09/04 13:51:32 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) was pointed to the Swift GRB210903.58 (trigger No 1071762,09h 01m 45.05s , -40d 19m 14.5s, R=0.0016) errorbox 42372 sec after notice time and 42385 sec after trigger time at 2021-09-04 01:34:44 UT, with upper limit up to 17.5 mag. The observations began at zenith distance = 82 deg. The sun altitude is -42.1 deg. MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB210903.58 errorbox 64806 sec after notice time and 64820 sec after trigger time at 2021-09-04 07:48:39 UT, with upper limit up to 17.9 mag. The observations began at zenith distance = 79 deg. The sun altitude is -38.7 deg. The galactic latitude b = 4 deg., longitude l = 263 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1708691 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 42476 | MASTER-SAAO | C | 180 | 16.8 | 43295 | MASTER-SAAO | C | 180 | 17.5 | 44439 | MASTER-SAAO | C | 180 | 17.4 | 45952 | MASTER-SAAO | C | 180 | 16.4 | 47353 | MASTER-SAAO | C | 180 | 15.8 | 48056 | MASTER-SAAO | C | 180 | 16.2 | 50216 | MASTER-SAAO | C | 180 | 15.0 | 64910 | MASTER-OAFA | C | 180 | 17.1 | 65324 | MASTER-OAFA | C | 180 | 17.3 | 65747 | MASTER-OAFA | C | 180 | 17.4 | 66756 | MASTER-OAFA | C | 180 | 17.6 | 67365 | MASTER-OAFA | C | 180 | 17.8 | 67779 | MASTER-OAFA | C | 180 | 17.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.

1 0

[vsnet-grb-info 28656] Fermi GRB 210903A: Global MASTER-Net observations report
by GCN Circulars 03 Sep '21

03 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30759 SUBJECT: Fermi GRB 210903A: Global MASTER-Net observations report DATE: 21/09/03 18:15:21 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-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB 210903A ( Fermi GBM team, GCN 30752) errorbox 56033 sec after notice time and 56098 sec after trigger time at 2021-09-03 17:25:15 UT, with upper limit up to 18.6 mag. Observations started at twilight. The observations began at zenith distance = 69 deg. The sun altitude is -12.8 deg. The galactic latitude b = 74 deg., longitude l = 164 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1708312 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 56128 | 2021-09-03 17:25:15 | MASTER-Tavrida | (12h 02m 08.49s , +38d 59m 08.2s) | C | 60 | 17.6 | 56207 | 2021-09-03 17:26:34 | MASTER-Tavrida | (12h 12m 24.55s , +39d 00m 39.2s) | C | 60 | 17.8 | 56438 | 2021-09-03 17:30:25 | MASTER-Tavrida | (12h 12m 59.54s , +40d 55m 06.6s) | C | 60 | 18.1 | 56517 | 2021-09-03 17:31:44 | MASTER-Tavrida | (12h 03m 33.73s , +42d 46m 35.9s) | C | 60 | 18.0 | 57008 | 2021-09-03 17:39:55 | MASTER-Tavrida | (12h 14m 34.76s , +42d 47m 02.0s) | C | 60 | 18.3 | 57404 | 2021-09-03 17:46:31 | MASTER-Tavrida | (12h 02m 01.58s , +38d 58m 43.9s) | C | 60 | 18.5 | 57483 | 2021-09-03 17:47:50 | MASTER-Tavrida | (12h 12m 26.04s , +38d 59m 03.2s) | C | 60 | 18.6 | 57562 | 2021-09-03 17:49:09 | MASTER-Tavrida | (12h 02m 26.10s , +40d 54m 08.7s) | C | 60 | 18.5 | 57641 | 2021-09-03 17:50:28 | MASTER-Tavrida | (12h 13m 03.20s , +40d 52m 36.4s) | C | 60 | 18.5 | 57720 | 2021-09-03 17:51:47 | MASTER-Tavrida | (12h 03m 41.09s , +42d 47m 32.7s) | C | 60 | 18.5 | 58369 | 2021-09-03 18:02:36 | MASTER-Tavrida | (11h 53m 47.03s , +42d 45m 34.2s) | C | 60 | 18.3 | 58448 | 2021-09-03 18:03:55 | MASTER-Tavrida | (12h 14m 40.54s , +42d 46m 09.0s) | C | 60 | 18.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.

1 0

[vsnet-grb-info 28655] GRB 210903C: Fermi GBM Final Real-time Localization
by GCN Circulars 03 Sep '21

03 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30758 SUBJECT: GRB 210903C: Fermi GBM Final Real-time Localization DATE: 21/09/03 17:37:06 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 17:26:58 UT on 3 Sep 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210903C (trigger 652382823.653196 / 210903727). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 155.0, Dec = 22.0 (J2000 degrees, equivalent to J2000 10h 20m, 22d 00'), with a statistical uncertainty of 4.2 degrees. The angle from the Fermi LAT boresight is 72.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210903727/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210903727/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210903727/…

1 0

[vsnet-grb-info 28654] GRB 210820A: TSHAO optical upper limit
by GCN Circulars 03 Sep '21

03 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30757 SUBJECT: GRB 210820A: TSHAO optical upper limit DATE: 21/09/03 17:11:38 GMT FROM: Alexei Pozanenko at IKI, Moscow <apozanen(a)iki.rssi.ru> S. Belkin (IKI), I. Reva (FAP), A. Kusakin (FAP), A. Pozanenko (IKI), N.Pankov (HSE), V. Kim (FAP) report on behalf of GRB-IKI-FuN: We observed GRB 210820A (Beardmore et al., GCN 30664) with Zeiss-1000 telescope of Tien Shan Astronomical Observatory starting on Aug. 21 (UT) 21:32:02. The optical afterglow (Beardmore et al., GCN 30664; Lipunov et al., GCN 30666; Fu et al., GCN 30669; Zhu et al., GCN 30670; Butler et al., GCN 30672; Strausbaugh et al., GCN 30673; Blazek et al., GCN 30674; Laha et al., GCN 30675; LaPorte and Beardmore, GCN 30686; Komesh et al., GCN 30688; Guelbenzu et al., GCN 30695; Kann et al., GCN 30731) was not detected in the stacked image down to a limiting magnitude of 21.8 in R filter. Preliminary photometry of the field in a stacked image is following. Date UT start t-T0 Filter Exp. OT Err. UL(3 sigma) (mid, days) (s) 2021-08-21 21:32:02 1.17659 R 27*90 n/d n/d 21.8 The photometry is based on nearby USNO-B1.0 stars. USNO-B1.0 RA Dec R2 01:22:01.52088 +04:35:30.2028 17.48 01:22:14.95944 +04:43:31.2204 17.89

1 0

[vsnet-grb-info 28653] Fermi GRB 210903B: Global MASTER-Net observations report
by GCN Circulars 03 Sep '21

03 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30756 SUBJECT: Fermi GRB 210903B: Global MASTER-Net observations report DATE: 21/09/03 17:00:29 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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 210903B ( Fermi GBM team, GCN 30754) errorbox 6219 sec after trigger time at 2021-09-03 02:14:25 UT, with upper limit up to 18.5 mag. The observations began at zenith distance = 67 deg. The sun altitude is -49.9 deg. The galactic latitude b = 17 deg., longitude l = 42 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1708736 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 6309 | 2021-09-03 02:14:25 | MASTER-OAFA | (18h 01m 44.08s , +25d 58m 19.7s) | C | 180 | 18.5 | 6910 | 2021-09-03 02:24:26 | MASTER-OAFA | (18h 01m 44.86s , +25d 57m 20.9s) | C | 180 | 18.5 | 7310 | 2021-09-03 02:31:06 | MASTER-OAFA | (18h 01m 47.01s , +25d 59m 20.6s) | C | 180 | 18.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.

1 0

[vsnet-grb-info 28652] GRB 210901A: GROND observations
by GCN Circulars 03 Sep '21

03 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30755 SUBJECT: GRB 210901A: GROND observations DATE: 21/09/03 16:41:33 GMT FROM: Ana Nicuesa at TLS Tautenburg <ana(a)tls-tautenburg.de> A. Nicuesa Guelbenzu, S. Klose (both TLS Tautenburg), and A. Rau (MPE Garching) report: We observed the field of GRB 210901A (Swift trigger #1071488; Laha et al., GCN 30746) simultaneously in g'r'i'z'JHK with GROND mounted at the 2.2m MPG telescope at La Silla Observatory (Chile). Observations started at 23:43 UT on September 1, about 8.5 hr after the GRB trigger. They were performed at an average seeing of 2.3 arcsec and at an average airmass of 1.5. Inside the 2.5 arcsec enhanced XRT error circle (Osborne et al., GCN 30749), we do not detect any source. Based on an observation with 23.4 minutes integration time in g'r'i'z' and 20 minutes in JHK, at a midtime of 23:43 UT on September 1, we measure the following preliminary 3-sigma upper limits (AB mags): g' > 23.5, r' > 23.6, i' > 22.6, J > 20.1, H > 19.7, and K > 16.3. We note the presence of an object at the north-western border of the XRT error circle at coordinates RA, DEC (J2000) = 19:41:05.98, -76:55:33.0 for which we measure r' = 21.33 +/- 0.05 mag (AB). Due to the relatively bad seeing at present we cannot decide with certainty if this is a galaxy or a star. Given magnitudes are calibrated against the SkyMapper catalog (Wolf et al., 2018, PASA 35, e010) in g'r'i'z' and 2MASS field stars in JHK (Skrutskie et al., 2006, AJ 131, 1163). We thank Maren Hempel for excellent support and for performing the observations.

1 0

[vsnet-grb-info 28651] GRB 210903B: Fermi GBM Final Localization
by GCN Circulars 03 Sep '21

03 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30754 SUBJECT: GRB 210903B: Fermi GBM Final Localization DATE: 21/09/03 16:37:03 GMT FROM: Joshua Wood at MSFC/Fermi-GBM <joshua.r.wood(a)nasa.gov> The Fermi GBM team reports the detection of a likely SHORT GRB At 00:30:46.05 UT on 3 Sep 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210903B (trigger 652321851 / 210903021). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 270.9, Dec = +15.6 (J2000 degrees, equivalent to J2000 18h 03m, +15d 36'), with a statistical uncertainty of 26.1 degrees. The angle from the Fermi LAT boresight is 66.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210903021/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210903021/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210903021/…

1 0