GRB 201208A
GCN Circular 29018
Subject
GRB 201208A: Swift-XRT afterglow detection
Date
2020-12-09T19:48:17Z (5 years ago)
From
Aaron Tohuvavohu at U Toronto <aaron.tohu@gmail.com>
A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU), J.A.
Kennea (PSU), 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 201208A (Dirirsa et al. GCN Circ. 29003),
collecting 5.0 ks of Photon Counting (PC) mode data between T0+70.4 ks
and T0+111.4 ks.
Four uncatalogued X-ray sources are detected, of which one ("Source 2")
is above the 2SXPS 3-sigma upper limit at this position, and is
therefore likely the GRB afterglow. Using 2046 s of PC mode data and 2
UVOT images, we find an enhanced XRT position (using the XRT-UVOT
alignment and matching UVOT field sources to the USNO-B1 catalogue):
RA, Dec = 158.32352, -28.71989 which is equivalent to:
RA (J2000): 10h 33m 17.64s
Dec(J2000): -28d 43' 11.6"
with an uncertainty of 3.1 arcsec (radius, 90% confidence). This
position is 112 arcsec from the Fermi/LAT position. The results of the
XRT-team automatic analysis of the likely afterglow are at
https://www.swift.ac.uk/ToO_GRBs/00021405/Source2.php.
The results of the full analysis of the XRT observations are available
at https://www.swift.ac.uk/ToO_GRBs/00021405.
This circular is an official product of the Swift-XRT team.
GCN Circular 29017
Subject
GRB 201208A: Fermi GBM observation
Date
2020-12-09T18:43:38Z (5 years ago)
From
Rachel Dunwoody at UCD <rachel.dunwoody@ucdconnect.ie>
R,Dunwoody (UCD), J.Mangan (UCD) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
At 06:03:23.25 UT on 08 December 2020, the Fermi Gamma-Ray Burst Monitor
(GBM)
triggered and located GRB 201208A (trigger 629100208 / 201208252)
which was also detected by the Fermi/LAT (F. Dirirsa et al. 2020, GCN 29003)
The Fermi GBM Final Real-time Localization (GCN 28998) is consistent with
the Fermi/LAT position.
This source was also detected by AstroSat (D. Nadella et al. 2020,
GCN29001).
The angle from the Fermi LAT boresight at the GBM trigger time is 11
degrees.
The GBM light curve consists of one main pulse
with a duration (T90) of about 45 s (50-300 keV).
The time-averaged spectrum from T0-14 s to T0+34 s is
best fit by a power law with an exponential high-energy cutoff.
The power law index is -0.87 +/- 0.07 and the cutoff energy,
parameterized as Epeak, is 254 +/- 24.
The event fluence (10-1000 keV) in this time interval is
(1.07 +/- 0.22)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+12 s in the 10-1000 keV band
is 5.1 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support
Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
GCN Circular 29015
Subject
GRB 201208A: LCO observations
Date
2020-12-09T15:55:55Z (5 years ago)
From
Luca Izzo at DARK/NBI <luca.izzo@gmail.com>
L. Izzo (DARK/NBI) and D. B. Malesani (DTU Space) report:
We observed the field of GRB 201208A (Fermi-GBM team, GCN #28998, Nadella et al., GCN #29001, Dirirsa et al., GCN #29003) with the Sinistro instrument mounted on the 1-m telescope of the LCO network located at the McDonald Observatory (Texas). Observations started on December 9 at 12:09:55 UT (1.25 days after the GRB trigger). We obtained a series of 5x120s images in r filter.
Within the XRT best candidate afterglow position at RA (J2000) = 10:33:17.64, Dec. (J2000) = -28:43:11.6, and with an error of 3.1" (see Evans, GCN #29002) we do not detect any optical afterglow candidate. In our stacked image we measure an upper limit value of r > 23 (AB mag), calibrated against nearby Pan-STARRS catalog stars.
This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 730890.
GCN Circular 29003
Subject
GRB 201208A: Fermi-LAT detection
Date
2020-12-09T03:07:46Z (5 years ago)
From
Magnus Axelsson at Stockholm U. <magaxe@kth.se>
F. Dirirsa (LAPP), N. Omodei (Stanford University), F. Longo (University and INFN Trieste), D. Kocevski (NASA/MSFC), M. Ohno (Hiroshima Univ. & Eotvos Univ.) and M. Axelsson (KTH and Stockholm Univ.) report on behalf of the Fermi-LAT Collaboration:
On December 08, 2020, Fermi-LAT detected high-energy emission from GRB 201208A, which was also detected by Fermi-GBM (trigger 201208252, GCN 28998) and AstroSat CZTI (GCN 29001).
The best LAT on-ground location is found to be
RA, Dec 158.3, -28.8 (degrees, J2000)
with an error radius of 0.16 deg (90% containment, statistical error only).
This was 11 deg from the LAT boresight at the time of the GBM trigger:
T0 = 06:03:23 UT.
The data from the Fermi-LAT show a significant increase in the event rate after the GBM trigger that is spatially correlated with the GBM emission with high significance. The photon flux above 100 MeV in the time interval 0-3000 s after the GBM trigger is (9.7+/-5.8)e-07 ph/cm2/s.
The estimated photon index above 100 MeV is -1.6 +/- 0.3.
The highest-energy photon is a 6.2 GeV event which is observed 1320 seconds after the GBM trigger.
A Swift ToO has been approved for this burst.
The Fermi-LAT point of contact for this burst is Feraol Fana Dirirsa (ffdirirsa@gmail.com).
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.
GCN Circular 29002
Subject
GRB 201208A: Swift ToO observations
Date
2020-12-09T01:35:18Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the Fermi/LAT GRB 201208A.
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021405
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 Fermi/LAT 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.
GCN Circular 29001
Subject
GRB 201208A: AstroSat CZTI detection
Date
2020-12-08T17:26:54Z (5 years ago)
From
Varun Bhalerao at Indian Inst of Tech <varunb@iitb.ac.in>
D. Nadella (NITK), A. Marathe (NITK), G. Waratkar (IITB), V. Shenoy (IITB), V. Bhalerao (IITB), A. Vibhute (IUCAA), S. Gupta (IUCAA), D. Bhattacharya (IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al, 2020, arXiv:2011.07067) showed detection of a long GRB 201208A, which was also detected by Fermi GBM Final Real-time (GCN #28998).
The source was clearly detected in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2020-12-08 06:03:32.500 UT. The measured peak count rate associated with the burst is 383 (+53, -58) cts/s above the background in the combined data of four quadrants, with a total of 2992 (+511, -554) cts. The local mean background count rate was 757 (+3, -5) cts/s. Using cumulative rates, we measure a T90 of 39.75 (+5, -14) s. A weak signal was also seen in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.
CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.
GCN Circular 28999
Subject
Fermi GRB 201208A: Global MASTER-Net observations report
Date
2020-12-08T08:15:45Z (5 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@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 201208A ( Fermi GBM team, GCN 28998) errorbox 129 sec after notice time and 199 sec after trigger time at 2020-12-08 06:06:42 UT, with upper limit up to 18.3 mag. The observations began at zenith distance = 47 deg. The sun altitude is -31.2 deg.
The galactic latitude b = 24 deg., longitude l = 269 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1497931
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
229 | 2020-12-08 06:06:42 | MASTER-OAFA | (10h 22m 26.04s , -30d 34m 40.3s) | C | 60 | 18.3 |
308 | 2020-12-08 06:08:01 | MASTER-OAFA | (10h 35m 33.22s , -32d 34m 16.4s) | C | 60 | 18.3 |
388 | 2020-12-08 06:09:21 | MASTER-OAFA | (10h 16m 42.48s , -32d 36m 29.2s) | C | 60 | 18.2 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 28998
Subject
GRB 201208A: Fermi GBM Final Real-time Localization
Date
2020-12-08T06:13:46Z (5 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
The Fermi GBM team reports the detection of a likely LONG GRB
At 06:03:23 UT on 8 Dec 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 201208A (trigger 629100208.248204 / 201208252).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 156.7, Dec = -29.3 (J2000 degrees, equivalent to J2000 10h 26m, -29d 18'), with a statistical uncertainty of 1.9 degrees.
The angle from the Fermi LAT boresight is 11.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201208252/quicklook/glg_skymap_all_bn201208252.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201208252/quicklook/glg_healpix_all_bn201208252.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201208252/quicklook/glg_lc_medres34_bn201208252.gif