GRB 200906A
GCN Circular 28386
Subject
Fermi GRB 200906A: Global MASTER-Net observations report
Date
2020-09-07T21:32:09Z (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-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 200906A ( Fermi GBM team, GCN 28370) errorbox 1 days 28040 sec after notice time and 1 days 28073 sec after trigger time at 2020-09-07 20:59:46 UT, with upper limit up to 18.7 mag. The observations began at zenith distance = 41 deg. The sun altitude is -39.4 deg.
The galactic latitude b = 30 deg., longitude l = 99 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1434684
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
114563 | 2020-09-07 20:59:46 | MASTER-Tavrida | (18h 06m 25.68s , +67d 46m 47.4s) | C | 180 | 18.6 |
114764 | 2020-09-07 21:03:07 | MASTER-Tavrida | (18h 06m 28.97s , +67d 47m 45.3s) | C | 180 | 18.7 |
114965 | 2020-09-07 21:06:28 | MASTER-Tavrida | (18h 06m 23.16s , +67d 46m 55.2s) | C | 180 | 18.6 |
115166 | 2020-09-07 21:09:49 | MASTER-Tavrida | (18h 06m 25.23s , +67d 47m 41.8s) | C | 180 | 18.7 |
115366 | 2020-09-07 21:13:09 | MASTER-Tavrida | (18h 06m 30.87s , +67d 46m 28.9s) | C | 180 | 18.7 |
115567 | 2020-09-07 21:16:30 | MASTER-Tavrida | (18h 06m 25.58s , +67d 45m 15.3s) | C | 180 | 18.6 |
115769 | 2020-09-07 21:19:52 | MASTER-Tavrida | (18h 06m 32.36s , +67d 45m 24.9s) | C | 180 | 18.6 |
115970 | 2020-09-07 21:23:13 | MASTER-Tavrida | (18h 06m 30.08s , +67d 46m 46.7s) | C | 180 | 18.6 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 28382
Subject
GRB 200906A: EMIR/GTC NIR upper limit
Date
2020-09-07T18:26:14Z (5 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D. A. Kann,
C. C. Thoene, M. Blazek, J. F. Agui Fernandez (all HETH/IAA-CSIC),
D. Reverte Paya (GTC) report:
We observed the field of GRB 200906A (Page et al., GCN #28371;
GBM detection: Fermi GBM Team, GCN #28370; Hamburg et al.,
GCN #28374) with EMIR on the 10.4m GTC telescope, at the Roque
de los Muchachos Observatory (La Palma, Spain). The observation
consisted of H-band imaging with a total integration time of 955 s, and
a mean epoch on the 6th of September at 23:57:35 UT (10.5753 hr
after the Swift trigger).
No source is detected within the refined XRT error circle (Beardmore
et al., GCN #28373) down to a 3-sigma limit of
H(AB) > 23.5 mag
This non detection is consistent with the previously reported limits
(Fu et al., GCN#28372; Kann et al., GCN#28376; Kumar et al.,
GCN#28377; Gropp et al., GCN#28379; Rossi et al. GCN#28381)
and confirms the dark nature of the burst.
GCN Circular 28381
Subject
GRB 200906A: LBT near-infrared upper limit
Date
2020-09-07T18:02:35Z (5 years ago)
From
Andrea Rossi at INAF <andrea.rossi@inaf.it>
A. Rossi (INAF-OAS) reports on behalf of the CIBO collaboration:
We observed the location of the X-ray afterglow (Beardmore et al., GCN
28373) of the Swift GRB 200906A (Page et al., GCN 28371) simultaneously
in the H and Ks bands with the LUCI near-infrared imager and
spectrograph mounted on the Large Binocular Telescope (LBT, Mt Graham,
AZ, USA).
Observations started at 03:57 UT on 2020-09-07, and allowed us to obtain
18 min of exposure in each band. Unfortunately, observations were
performed under variable sky conditions with passing clouds.
Inspection of the combined H-band images (mid-time of 0.628 days after
the GRB), does not reveal any source down to the limiting magnitude
H<21.8 mag (AB system).
A preliminary comparison of the simultaneous Swift/XRT flux of 1.06e-07
Jy at a mid-frequency 3.8E+17 Hz (1.6 keV), gives a X-ray to infrared
slope-index b_OX<0.5, confirming the dark nature of this GRB. This XRT
flux has been obtained modelling the XRT lightcurve after 200 seconds
with a power-law with decay-index 0.60+-0.04.
We acknowledge the excellent support from the LBTO and LBT-INAF staff,
particularly B. Rothberg, F. Cusano, S. Paiano and D. Paris, in
obtaining these observations.
GCN Circular 28380
Subject
GRB 200906A: Swift-BAT refined analysis
Date
2020-09-07T16:58:46Z (5 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), K. L. Page (U Leicester),
T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 200906A (trigger #994856)
(Page et al., GCN Circ. 28371). The BAT ground-calculated position is
RA, Dec = 272.284, 67.887 deg which is
RA(J2000) = 18h 09m 08.2s
Dec(J2000) = +67d 53' 13.4"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 97%.
The mask-weighted light curve shows a double-peaked structure. The first
pulse starts at ~T-9 s and peaks at ~T+5 s. The second pulse starts
at ~T+46 s, peaks at ~T+51 s, and ends at ~T+90 s. T90 (15-350 keV)
is 70.90 +- 7.63 sec (estimated error including systematics).
The time-averaged spectrum from T-8.70 to T+90.01 sec is best fit by
a simple power-law model. The power law index of the time-averaged
spectrum is 2.00 +- 0.09. The fluence in the 15-150 keV band
is 2.8 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured
from T+50.96 sec in the 15-150 keV band is 2.5 +- 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/994856/BA/
GCN Circular 28379
Subject
GRB 200906A: Swift/UVOT Upper Limits
Date
2020-09-07T16:13:35Z (5 years ago)
From
Sam LaPorte at PSU <sjl5346@psu.edu>
GRB 200906A: Swift/UVOT Upper Limits
J. D. Gropp (PSU) and K. L. Page (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 200906A
76 s after the BAT trigger (Page et al., GCN Circ. 28371).
No optical afterglow consistent with the XRT position
(Beardmore et al. GCN Circ. 28373)
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 76 226 147 >21.2
u_FC 289 538 246 >20.4
white 76 5054 472 >21.3
v 618 1413 97 >19.4
b 544 4948 274 >20.1
u 289 1487 324 >20.4
w1 668 1462 97 >19.3
m2 643 1438 78 >20.1
w2 594 1389 97 >19.5
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.05 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 28377
Subject
GRB 200906A: GROWTH-India Telescope (GIT) optical r band upper limit
Date
2020-09-07T05:16:01Z (5 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
H. Kumar (IITB), P. Dorje (IIA), V. Bhalerao(IITB), G. C. Anupama(IIA), S.
Barway(IIA), report on behalf of the GROWTH-India collaboration:
We observed GRB200906A reported by Swift-BAT (K. L. Page et al., (GCN
28371), see also S.Y. Fu et al.,(GCN 28372), A.P. Beardmore
Et al., (GCN 28373), R. Hamburg et al., (GCN 28374) & D. A. Kann et al.,
(GCN 28376) with 0.7m GROWTH-India telescope. The field was observed in the
SDSS r filter starting at 2020-09-06T16:34:48 UT i.e. ~ 3.33 hrs after the
event detection by Swift-BAT. We didn���t find any new source within an
uncertainty region of 1.9 arcsec around Ra(J2000) = 18:09:06.08, Dec(J2000)
= +67:52:48.1 (GCN 28373) with an upper limit of*: *
r > 20.14 mag
(calibrated against PanSTARRs PS1 data release, Flewelling et al., 2018)
The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7-degree
field of view, set up by the Indian Institute of Astrophysics and the
Indian Institute of Technology Bombay with support from the Indo-US Science
and Technology Forum (IUSSTF) and the Science and Engineering Research
Board (SERB) of the Department of Science and Technology (DST), Government
of India (https://sites.google.com/view/growthindia/). It is located at the
Indian Astronomical Observatory (Hanle), operated by the Indian Institute
of Astrophysics (IIA).
GCN Circular 28376
Subject
GRB 200906A: OSN 1.5m Upper Limit
Date
2020-09-07T03:31:53Z (5 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC,
DARK/NBI), C. C. Thoene, M. Blazek, J. F. Agui Fernandez (all
HETH/IAA-CSIC), and V. Casanova (IAA-CSIC) report:
We observed the location (Beardmore et al., GCN #28373) of the Swift GRB
200906A (Page et al., GCN #28371; GBM detection: Fermi GBM Team, GCN
#28370, Hamburg et al., GCN #28374) with the 1.5m telescope of the
Observatorio Sierra Nevada, in Granada, Spain. We obtained 78 x 100 s
images beginning 2020-09-06 21:29:03.51 UT, after clouds had cleared.
In a stack of all images, centered at 0.39467 days after the GRB, no
source is detected at the enhanced XRT position. Measured against two
nearby USNO-B1.0 stars, we derive an upper limit of
Ic > 23.4 mag.
This agrees with the non-detection reported by Fu et al. (GCN #28372).
We note the refined XRT analysis (Beardmore et al., GCN #28375) also
reports an NH column density significantly exceeding the Galactic value,
indicating this is a dark GRB.
GCN Circular 28375
Subject
GRB 200906A: Swift-XRT refined Analysis
Date
2020-09-07T03:03:23Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A.P. Beardmore (U. Leicester), E. Ambrosi (INAF-IASFPA) , M. Capalbi
(INAF-IASFPA), M. Perri (ASDC), B. Sbarufatti (PSU), D.N. Burrows
(PSU), J. D. Gropp (PSU), P.A. Evans (U. Leicester) and K.L. Page
report on behalf of the Swift-XRT team:
We have analysed 6.8 ks of XRT data for GRB 200906A (Page et al. GCN
Circ. 28371), from 70 s to 41.5 ks after the BAT trigger. The data
comprise 121 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Beardmore et al. (GCN Circ. 28373).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.60 (+/-0.05).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.11 (+/-0.09). The
best-fitting absorption column is 7.2 (+0.7, -0.6) x 10^21 cm^-2, in
excess of the Galactic value of 5.2 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 2.22 (+0.26, -0.24)
and a best-fitting absorption column of 7.0 (+1.7, -1.5) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.9 x 10^-11 (8.0 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 7.0 (+1.7, -1.5) x 10^21 cm^-2
Galactic foreground: 5.2 x 10^20 cm^-2
Excess significance: 7.1 sigma
Photon index: 2.22 (+0.26, -0.24)
If the light curve continues to decay with a power-law decay index of
0.60, the count rate at T+24 hours will be 0.013 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.2 x
10^-13 (1.1 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00994856.
This circular is an official product of the Swift-XRT team.
GCN Circular 28374
Subject
GRB 200906A: Fermi GBM detection
Date
2020-09-07T00:03:11Z (5 years ago)
From
Christian Malacaria at NASA-MSFC/USRA <cmalacaria@usra.edu>
R. Hamburg (UAH), C. Malacaria (NASA-MSFC/USRA) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 13:11:53.38 UT on 06 September 2020, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 200906A (trigger 621090718 / 200906550)
which was also detected by the Swift/BAT and Swift/XRT (Page et al. 2020, GCN 28371).
The Fermi GBM Final Real-time Localization (GCN 28370) is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 74 degrees.
The GBM light curve shows two peaks
with a duration (T90) of about 67.3 s (50-300 keV), starting at T0-49 s.
The time-averaged spectrum from T0-4.1 s to T0+16.4 s is
best fit by a Band function with Epeak = 50.5 +/- 9.9 keV,
alpha = -1.1 +/- 0.2 , and beta = -2.1 +/- 0.1
The event fluence (10-1000 keV) in this time interval is
(3.9 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.8 s in the 10-1000 keV band
is 4.5 +/- 0.2 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 28373
Subject
GRB 200906A: Enhanced Swift-XRT position
Date
2020-09-06T21:22:01Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@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 687 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 200906A, 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 = 272.27532, +67.88001 which is equivalent
to:
RA (J2000): 18h 09m 6.08s
Dec (J2000): +67d 52' 48.1"
with an uncertainty of 1.9 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.
GCN Circular 28372
Subject
GRB 200906A: Nanshan/NEXT optical upper limit
Date
2020-09-06T16:18:07Z (5 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
S.Y. Fu, Z.P. Zhu, X. Liu, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High
School), X. Zhang, J.Z. Liu (XAO) report:
We observed the field of GRB 200906A (Page et al., GCN 28371) using the
NEXT-0.6m telescope located at Nanshan, Xinjiang, China. We only
obtained 2x120s frames in the Sloan r-band due to the cloudy weather,
starting at 15:03:47 UT on 2020-09-06, i.e., 1.88 hr after the BAT trigger.
No optical source is detected in our stacked image at the XRT position
(Page et al., GCN 28371), down to a limiting magnitude of r~19.3,
calibrated with the nearby PanSTARRS field.
GCN Circular 28371
Subject
GRB 200906A: Swift detection of a burst
Date
2020-09-06T13:26:53Z (5 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
K. L. Page (U Leicester), D. N. Burrows (PSU), J.D. Gropp (PSU),
S. Laha (GSFC/UMBC/CRESST), A. Y. Lien (GSFC/UMBC) and
D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 13:11:04 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 200906A (trigger=994856). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 272.293, +67.852 which is
RA(J2000) = 18h 09m 10s
Dec(J2000) = +67d 51' 08"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed two main peaks
with a duration of about 80 sec. The second, larger, peak extends
past the end of the slew and into the interval observed by XRT and UVOT.
The peak count rate was ~3000 counts/sec (15-350 keV),
at ~52 sec after the trigger.
The XRT began observing the field at 13:12:10.8 UT, 66.7 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source with an enhanced position: RA, Dec 272.2731,
67.8791 which is equivalent to:
RA(J2000) = 18h 09m 05.54s
Dec(J2000) = +67d 52' 44.8"
with an uncertainty of 2.6 arcseconds (radius, 90% containment). This
location is 101 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.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (5.25 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 5.5
(+6.91/-5.25) x 10^21 cm^-2 (90% confidence).
The initial flux in the 0.1 s image was 2.09e-08 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 76 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 19.6 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 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.05.
Burst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk).
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/)
GCN Circular 28370
Subject
GRB 200906A: Fermi GBM Final Real-time Localization
Date
2020-09-06T13:22:12Z (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 13:11:53 UT on 6 Sep 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 200906A (trigger 621090718.377264 / 200906550).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 270.0, Dec = 68.6 (J2000 degrees, equivalent to J2000 18h 00m, 68d 35'), with a statistical uncertainty of 4.1 degrees.
The angle from the Fermi LAT boresight is 83.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200906550/quicklook/glg_skymap_all_bn200906550.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/bn200906550/quicklook/glg_healpix_all_bn200906550.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200906550/quicklook/glg_lc_medres34_bn200906550.gif