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

[vsnet-grb-info 28670] GRB 210905A: DECam Detection
by GCN Circulars 05 Sep '21

05 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30773 SUBJECT: GRB 210905A: DECam Detection DATE: 21/09/05 11:56:22 GMT FROM: Dougal Dobie at VAST <ddobie94(a)gmail.com> J. Cooke (Swinburne), S. Webb (Swinburne), D. Dobie (Swinburne), J. Zhang (Swinburne), S. Hegarty (Swinburne), A. Moller (Swinburne), S. Goode (Swinburne), R. Strausbaugh (U. of the Virgin Islands), Tim Abbott (NOIRLab), Vivek Gupta (Swinburne), Mark Suhr (Swinburne) We observed Swift GRB 210905A (Sonbas, et al., GCN 30765) with the Dark Energy Camera (DECam) at Cerro Tololo Inter-American Observatory. We performed 3x60s exposures with the i filter on September 5, from 04:46:10 to 04:50:09 UT. We make a marginal detection of a source at the position reported by Strausbaugh et al. (GCN 30769) with i=23.6. This measurement is not corrected for galactic extinction.

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[vsnet-grb-info 28669] GRB 210905A: REM NIR afterglow detection
by GCN Circulars 05 Sep '21

05 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30772 SUBJECT: GRB 210905A: REM NIR afterglow detection DATE: 21/09/05 07:42:23 GMT FROM: Paolo D'Avanzo at INAF-OAB <pda.davanzo(a)gmail.com> P. D'Avanzo, A. Melandri, S. Covino, D. Fugazza (INAF-OAB), on behalf of the REM team, report: We observed the field of GRB 210905A (Sonbas, et al., GCN 30765) with the REM 60cm robotic telescope located at the ESO premise of La Silla (Chile). The observations were carried in the g, r, i, z, J, H and K bands, starting on 2021 September 05 at 00:19:49 UT (i.e. 428 seconds after the burst) and lasting for about three hours. At the position of the optical afterglow (Strausbaugh & Cucchiara, GCN Circ. 30769) we detected an uncatalogued source in all NIR bands. From preliminary photometry we derive the following magnitude: H = 14.82 +/- 0.15 (Vega; calibrated against the 2MASS catalogue) at a mid time of t-t0 = 469 seconds.

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[vsnet-grb-info 28668] GRB 210905A: VLT/X-shooter spectroscopic redshift
by GCN Circulars 05 Sep '21

05 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30771 SUBJECT: GRB 210905A: VLT/X-shooter spectroscopic redshift DATE: 21/09/05 06:06:26 GMT FROM: Andrea Rossi at INAF <andrea.rossi(a)inaf.it> N. Tanvir (Univ. Leicester), A. Rossi (INAF-OAS), D. Xu (NAOC), Z.P. Zhu (NAOC,HUST), L. Izzo (DARK/NBI), D. A. Kann (HETH/IAA-CSIC), and A.J. Levan (Radboud) report on behalf of the Stargate collaboration: We observed the location of the afterglow (Strausbaugh & Cucchiara, GCN 30769, 30770) of GRB 210905A (Sonbas et al., GCN 30765) using the ESO VLT UT3 (Melipal) equipped with the X-shooter spectrograph. Our spectra cover the wavelength range 3000-21000 AA, and consist of 4 exposures by 1200 s each. Our observations started on 2021 September 05 at 02:44 UT, ~2.53 hours after the GRB detection. In the acquisition image obtained between 2.53 and 2.73 hours after the burst, the afterglow is well detected at I and z-bands, but not in the r-band, confirming the red color already noted by Strausbaugh & Cucchiara. We measure the following AB magnitudes: r>23.5 I=20.3+-0.1 z=19.4+-0.1 Spectroscopy of the source reveals a continuum well detected in the red part of visible arm. A clear break is detected around 9000AA which we interpret as the Lyman-alpha break at z = 6.318, and explains the strong r-z color as due to Lyman dropout. Other lines such as Fe II, Al II, C IV and Si II are visible and display a double absorption profile, which is possibly due to different intervening systems at z1 = 6.312 and z2 = 6.318. We thus conclude that z=6.318 is the redshift of GRB 210905A. Further analysis is undergoing. We acknowledge support from the ESO observing staff at Paranal, in particular Israel Blanchard, Michael Abdul-Masih, and Matias Jones.

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[vsnet-grb-info 28667] GRB 210905A: Continued LCO Optical Observations
by GCN Circulars 05 Sep '21

05 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30770 SUBJECT: GRB 210905A: Continued LCO Optical Observations DATE: 21/09/05 04:33:24 GMT FROM: Robert Strausbaugh at U. of the Virgin Islands <robert.strausbaugh(a)uvi.edu> R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration: We observed Swift GRB 210905A (Sonbas, et al., GCN 30765) with the LCO 1-m Sinistro instrument at the Cerro Tololo Interamerican Observatory, Chile site, on September 5, from 02:32 to 02:53 UT (corresponding to 2.37 to 2.72 hours from the GRB trigger time) with the Bessel I filter. We performed a series of 5x300s exposures in I band. We detect the same uncataloged source (Strausbaugh, et al., GCN 30769) at the following coordinates (309.0481637, -44.4402618). Using the USNO-B.1 catalog as reference, we calculate the following magnitude: I=20.4+/-0.1 These magnitudes are not corrected for galactic extinction. There is clear evidence of fading from the first epoch (I=19.52+/-0.09) providing strong evidence that this is the afterglow of this burst. R.S. is funded by NSF AST grant #1831682

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[vsnet-grb-info 28666] GRB 210905A: LCO Optical Detection
by GCN Circulars 05 Sep '21

05 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30769 SUBJECT: GRB 210905A: LCO Optical Detection DATE: 21/09/05 03:00:50 GMT FROM: Robert Strausbaugh at U. of the Virgin Islands <robert.strausbaugh(a)uvi.edu> R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration: We observed Swift GRB 210905A (Sonbas, et al., GCN 30765) with the LCO 1-m Sinistro instrument at the Cerro Tololo Interamerican Observatory, Chile site, on September 5, from 01:09 to 01:36 UT (corresponding to 0.95 to 1.40 hours from the GRB trigger time) with the Bessel R and I filters. We performed a series of 3x300s exposures in R and I. In the XRT detection region (Sonbas, et al., GCN 30765) we detect an uncatalogued source in I band at the following coordinates (309.0481637, -44.4402618). Using the USNO-B.1 catalog as reference, we calculate the following magnitudes and upper limits: R>22.44 I=19.52+/-0.09 These magnitudes are not corrected for galactic extinction. The detection in I and the lack of detection in R is suggestive of a high-z source. As such additional follow-up is encouraged. Additional LCO measurements are underway. R.S. is funded by NSF AST grant #1831682

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[vsnet-grb-info 28665] GRB 210905A: Enhanced Swift-XRT position
by GCN Circulars 05 Sep '21

05 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30768 SUBJECT: GRB 210905A: Enhanced Swift-XRT position DATE: 21/09/05 02:27:23 GMT FROM: Phil Evans at U of Leicester <pae9(a)leicester.ac.uk> A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 97 s of XRT Photon Counting mode data and 1 UVOT images for GRB 210905A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 309.04826, -44.43956 which is equivalent to: RA (J2000): 20h 36m 11.58s Dec (J2000): -44d 26' 22.4" with an uncertainty of 2.6 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team.

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[vsnet-grb-info 28664] GRB 210901A: Swift/UVOT Upper Limits
by GCN Circulars 05 Sep '21

05 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30767 SUBJECT: GRB 210901A: Swift/UVOT Upper Limits DATE: 21/09/05 00:48:10 GMT FROM: Mike Siegel at PSU/Swift MOC <mhs18(a)psu.edu> M. H. Siegel (PSU) and S. L. Laha (GSFC/UMBC/CRESST) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 210901A 158 s after the BAT trigger (Laha et al., GCN Circ. 30746). No optical afterglow consistent with the XRT position (Osborne et al. GCN Circ. 30749) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 158 308 147 >20.9 u_FC 316 566 246 >19.6 white 158 974 289 >20.9 v 646 839 39 >17.8 b 572 764 39 >18.8 u 316 740 265 >19.8 w1 695 715 19 >17.8 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.200 in the direction of the burst (Schlegel et al. 1998).

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[vsnet-grb-info 28663] Swift GRB 210905A: Global MASTER-Net observations report
by GCN Circulars 05 Sep '21

05 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30766 SUBJECT: Swift GRB 210905A: Global MASTER-Net observations report DATE: 21/09/05 00:32:44 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 GRB 210905A ( E. Sonbas et al., GCN 30765) errorbox 6 sec after notice time and 414 sec after trigger time at 2021-09-05 00:19:36 UT, with upper limit up to 19.1 mag. The observations began at zenith distance = 48 deg. The sun altitude is -55.5 deg. The galactic latitude b = -37 deg., longitude l = 356 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1709881 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 455 | MASTER-SAAO | P\ | 80 | 18.2 | 565 | MASTER-SAAO | P\ | 300 | 19.1 | Coadd 556 | MASTER-SAAO | P\ | 100 | 18.3 | 678 | MASTER-SAAO | P\ | 120 | 18.5 | 826 | MASTER-SAAO | P\ | 150 | 18.5 | The observation and reduction will continue. The message may be cited.

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[vsnet-grb-info 28662] GRB 210905A: Swift detection of a burst
by GCN Circulars 05 Sep '21

05 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30765 SUBJECT: GRB 210905A: Swift detection of a burst DATE: 21/09/05 00:28:29 GMT FROM: David Palmer at LANL <palmer(a)lanl.gov> E. Sonbas (Adiyaman Univ.), E. Ambrosi (INAF-IASFPA), A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC & INAF-OAR), C. Gronwall (PSU), S. Laha (GSFC/UMBC/CRESST), A. Y. Lien (U Tampa), F. E. Marshall (NASA/GSFC) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team: At 00:12:41 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 210905A (trigger=1071993). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 309.062, -44.431 which is RA(J2000) = 20h 36m 15s Dec(J2000) = -44d 25' 50" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of at least 30 sec. The peak count rate was ~1500 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 00:14:13.0 UT, 91.7 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 309.04815, -44.43959 which is equivalent to: RA(J2000) = 20h 36m 11.56s Dec(J2000) = -44d 26' 22.5" with an uncertainty of 7.0 arcseconds (radius, 90% containment). This location is 47 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper. No spectrum from the promptly downlinked event data is yet available to determine the column density. The initial flux in the 2.5 s image was 1.23e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 250 seconds with the U filter starting 156 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.2 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.034. Burst Advocate for this burst is E. Sonbas (edasonbas AT yahoo.com) Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)

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[vsnet-grb-info 28661] Fermi GRB 210904A: Global MASTER-Net observations report
by GCN Circulars 05 Sep '21

05 Sep '21

TITLE: GCN CIRCULAR NUMBER: 30764 SUBJECT: Fermi GRB 210904A: Global MASTER-Net observations report DATE: 21/09/05 00:15:17 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 210904A ( Fermi GBM team, GCN 30763) errorbox 8467 sec after notice time and 8548 sec after trigger time at 2021-09-04 23:10:08 UT, with upper limit up to 18.4 mag. The observations began at zenith distance = 81 deg. The sun altitude is -63.8 deg. The galactic latitude b = -6 deg., longitude l = 260 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1709787 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 8579 | 2021-09-04 23:10:08 | MASTER-SAAO | (07h 13m 56.09s , -50d 06m 24.2s) | C | 60 | 17.5 | 8818 | 2021-09-04 23:14:07 | MASTER-SAAO | (07h 19m 10.91s , -51d 59m 24.1s) | C | 60 | 17.7 | 9296 | 2021-09-04 23:22:05 | MASTER-SAAO | (07h 08m 22.61s , -48d 12m 57.4s) | C | 60 | 17.8 | 9376 | 2021-09-04 23:23:25 | MASTER-SAAO | (07h 38m 53.16s , -53d 54m 13.5s) | C | 60 | 17.9 | 9536 | 2021-09-04 23:26:05 | MASTER-SAAO | (07h 13m 58.12s , -50d 07m 33.3s) | C | 60 | 17.8 | 9775 | 2021-09-04 23:30:04 | MASTER-SAAO | (07h 19m 06.81s , -51d 59m 26.1s) | C | 60 | 17.8 | 9854 | 2021-09-04 23:31:23 | MASTER-SAAO | (07h 32m 12.17s , -51d 59m 49.4s) | C | 60 | 17.7 | 10014 | 2021-09-04 23:34:03 | MASTER-SAAO | (07h 04m 54.17s , -46d 20m 01.5s) | C | 60 | 18.0 | 10253 | 2021-09-04 23:38:02 | MASTER-SAAO | (07h 08m 27.37s , -48d 12m 23.6s) | C | 60 | 18.1 | 10333 | 2021-09-04 23:39:22 | MASTER-SAAO | (07h 20m 20.55s , -48d 12m 41.9s) | C | 60 | 17.8 | 10412 | 2021-09-04 23:40:41 | MASTER-SAAO | (07h 38m 52.71s , -53d 52m 36.0s) | C | 60 | 18.0 | 10492 | 2021-09-04 23:42:01 | MASTER-SAAO | (07h 52m 31.79s , -53d 52m 56.7s) | C | 60 | 18.0 | 10651 | 2021-09-04 23:44:40 | MASTER-SAAO | (07h 13m 59.74s , -50d 08m 01.5s) | C | 60 | 18.1 | 10890 | 2021-09-04 23:48:40 | MASTER-SAAO | (07h 19m 12.08s , -52d 00m 03.6s) | C | 60 | 18.2 | 10970 | 2021-09-04 23:49:59 | MASTER-SAAO | (07h 32m 06.04s , -52d 00m 12.5s) | C | 60 | 18.0 | 11130 | 2021-09-04 23:52:39 | MASTER-SAAO | (07h 04m 54.64s , -46d 19m 44.5s) | C | 60 | 18.3 | 11369 | 2021-09-04 23:56:38 | MASTER-SAAO | (07h 08m 23.65s , -48d 12m 55.9s) | C | 60 | 18.4 | 11449 | 2021-09-04 23:57:58 | MASTER-SAAO | (07h 20m 23.73s , -48d 13m 57.4s) | C | 60 | 18.1 | 11528 | 2021-09-04 23:59:17 | MASTER-SAAO | (07h 38m 57.95s , -53d 53m 04.8s) | C | 60 | 18.3 | 11608 | 2021-09-05 00:00:37 | MASTER-SAAO | (07h 52m 26.26s , -53d 53m 22.3s) | C | 60 | 18.0 | 11691 | 2021-09-05 00:02:00 | MASTER-SAAO | (07h 25m 12.86s , -50d 06m 49.5s) | C | 60 | 18.2 | 11771 | 2021-09-05 00:03:20 | MASTER-SAAO | (07h 37m 35.60s , -50d 07m 15.3s) | C | 60 | 18.0 | 11850 | 2021-09-05 00:04:39 | MASTER-SAAO | (07h 43m 49.99s , -51d 59m 23.6s) | C | 60 | 17.9 | 11930 | 2021-09-05 00:05:59 | MASTER-SAAO | (07h 56m 49.28s , -52d 00m 07.8s) | C | 60 | 17.9 | 12010 | 2021-09-05 00:07:19 | MASTER-SAAO | (07h 31m 08.10s , -48d 12m 41.2s) | C | 60 | 18.1 | 12089 | 2021-09-05 00:08:39 | MASTER-SAAO | (07h 43m 08.49s , -48d 11m 09.0s) | C | 60 | 17.8 | 12169 | 2021-09-05 00:09:58 | MASTER-SAAO | (07h 48m 48.15s , -50d 06m 50.2s) | C | 60 | 17.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.

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