GRB 200509A
GCN Circular 27701
Subject
GRB 200509A: Swift detection of a burst with a possible optical counterpart
Date
2020-05-09T07:08:31Z (5 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
E. Troja (NASA/GSFC/UMCP), V. D'Elia (SSDC), J.D. Gropp (PSU),
N. J. Klingler (PSU), K. L. Page (U Leicester), B. Sbarufatti (PSU),
M. H. Siegel (PSU) and A. Tohuvavohu (U Toronto) report on behalf of
the Neil Gehrels Swift Observatory Team:
At 06:47:17 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 200509A (trigger=970886). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 116.450, -4.641 which is
RA(J2000) = 07h 45m 48s
Dec(J2000) = -04d 38' 28"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a multi-peaked
structure with a duration of about 20 sec. There is also possible
further activity for several hundred seconds The peak count rate
was ~1400 counts/sec (15-350 keV), at ~4 sec after the trigger.
The XRT began observing the field at 06:49:16.9 UT, 119.6 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 116.42333, -4.63131 which is equivalent
to:
RA(J2000) = 07h 45m 41.60s
Dec(J2000) = -04d 37' 52.7"
with an uncertainty of 3.5 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. We cannot determine whether the source
is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.58 x
10^21 cm^-2, Willingale et al. 2013), with an excess column of 5.2
(+4.12/-3.39) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of nominal 150.000 seconds with the White
filter starting 123 seconds after the BAT trigger. There is a candidate
afterglow in the list of sources generated on-board at
RA(J2000) = 07:45:41.20 = 116.42166
DEC(J2000) = -04:37:49.4 = -4.63040
with a 90%-confidence error radius of about 1.10 arc sec. This position is 6.4
arc sec. from the center of the XRT error circle. The estimated magnitude is
19.15. No correction has been made for the expected extinction corresponding to
E(B-V) of 0.13. The 2.7'x2.7' sub-image does not cover the region of
this potential counterpart.
Burst Advocate for this burst is E. Troja (eleonora.troja AT nasa.gov).
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 27702
Subject
GRB 200509A: Zadko observatory - Gingin optical upper limits
Date
2020-05-09T14:04:56Z (5 years ago)
From
Bruce Gendre at UVI <bruce.gendre@gmail.com>
B. Gendre, E. Moore, D. Coward, J.A. Moore (OzGrav-UWA),
A. Klotz (IRAP-CNRS-OMP) report:
We imaged the field of GRB 200509A detected by Swift
(trigger 970886, GCN 27701, Troja et al. 2020) with the Zadko robotic
telescope (D=100cm) located at the Zadko Observatory - Gingin, Australia.
The observations started about 6 hours after the GRB trigger. The
elevation of the field was at 41 degrees above horizon at the start of
the observation and decreasing, and weather conditions were good.
Inside the error box of the XRT afterglow, we did not detect any object
at 2020-05-09T13:00:00, down to a R magnitude of 18.2. No further
observations are planned.
Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.
This message may be cited.
GCN Circular 27703
Subject
GRB 200509A: Enhanced Swift-XRT position
Date
2020-05-09T16:15:06Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 799 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 200509A, 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 = 116.42238, -4.63042 which is equivalent
to:
RA (J2000): 07h 45m 41.37s
Dec (J2000): -04d 37' 49.5"
with an uncertainty of 1.7 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 27704
Subject
GRB 200509A: Swift-XRT refined Analysis
Date
2020-05-09T18:28:52Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto),
B. Sbarufatti (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U.
Leicester), P.A. Evans (U. Leicester), A. Melandri (INAF-OAB), T.
Sbarrato (INAF-OAB) and E. Troja report on behalf of the Swift-XRT
team:
We have analysed 9.4 ks of XRT data for GRB 200509A (Troja et al. GCN
Circ. 27701), from 104 s to 34.9 ks after the BAT trigger. The data
comprise 7 s in Windowed Timing (WT) mode (taken while Swift was
slewing), with the remainder in Photon Counting (PC) mode. The enhanced
XRT position for this burst was given by Evans et al. (GCN Circ.
27703). The late-time light curve (from T0+5.0 ks) is consistent with a
constant source of mean count rate 1.8e-01 ct/sec. A power-law fit
gives an index of -0.2 (+/-1.2).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.725 (+/-0.020). The
best-fitting absorption column is 1.89 (+0.08, -0.07) x 10^21 cm^-2,
in excess of the Galactic value of 1.6 x 10^21 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.55 (+0.10, -0.08)
and a best-fitting absorption column consistent with the Galactic
value. The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 4.5 x 10^-11 (5.1 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.58 (+0.17, -0.00) x 10^21 cm^-2
Galactic foreground: 1.6 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.55 (+0.10, -0.08)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00970886.
This circular is an official product of the Swift-XRT team.
GCN Circular 27705
Subject
GRB 200509A: LCO Optical Afterglow Detection
Date
2020-05-09T18:36:17Z (5 years ago)
From
Robert Strausbaugh at U. of the Virgin Islands <robert.strausbaugh@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 200509A (Troja et al., GCN 27701) with the LCO 1-m Sinistro instrument at the South African Astronomical Observatory site, on May 9, from 16:46 to 17:08 UT (corresponding to 9.63 to 10.0 hours from the GRB trigger time) with the Bessel R and I filters.
We performed a series of 5x120s exposures in R and I. We detect an optical source in stacked images within the Enhanced Swift-XRT position (Evans et al., GCN 27703) that is not present in either USNO or 2MASS catalogs. Using the USNO-B.1 catalog as reference, we calculate the following magnitudes:
R = 20.94 +/- 0.09
I = 19.44 +/- 0.18
These magnitudes are not corrected for galactic extinction.
R.S. is funded by NSF AST grant #1831682
GCN Circular 27706
Subject
Swift GRB 200509A: Global MASTER-Net observations report
Date
2020-05-09T19:38:22Z (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),
H.Levato
(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE),
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 200509A ( E. Troja et al., GCN 27701) errorbox 42927 sec after notice time and 42979 sec after trigger time at 2020-05-09 18:43:37 UT, with upper limit up to 19.1 mag. The observations began at zenith distance = 56 deg. The sun altitude is -36.1 deg.
The galactic latitude b = 10 deg., longitude l = 224 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1352906
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
43070 | MASTER-SAAO | C | 180 | 19.1 |
43070 | MASTER-SAAO | C | 180 | 19.0 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 27709
Subject
GRB 200509A: Swift/UVOT Detection
Date
2020-05-10T00:34:40Z (5 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 200509A
123 s after the BAT trigger (Troja et al., GCN Circ. 27701). A source
consistent with the XRT position (Troja et al. GCN Circ. 27701) is
detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 07:45:41.28 = 116.42200 (deg.)
Dec (J2000) = -04:37:49.3 = -4.63035 (deg.)
with an estimated uncertainty of 0.48 arc sec. (radius, 90% confidence).
Preliminary detections and 3-sigma upper limits using the UVOT
photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 123 273 147 18.92 +/- 0.08
v 611 1738 122 >18.6
b 537 1678 117 >19.8
u 281 531 246 18.46 +/- 0.10
w1 660 1628 117 >19.0
m2 636 1604 117 >19.0
w2 587 1728 136 >19.6
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.13 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 27710
Subject
GRB 200509A: GROWTH-India r band upper limits
Date
2020-05-10T06:30:58Z (5 years ago)
From
Varun Bhalerao at Indian Inst of Tech <varunb@iitb.ac.in>
H. Kumar, V. Bhalerao(IITB), G. C. Anupama, S. Barway, T. Stanzin (IIA), J. Stanzin (IAO) report on behalf of the GROWTH-India collaboration:
We observed GRB200509A reported by (Troja et al., GCN 27701, Gendre et al., GCN 27702, Evans et al., GCN 27703, Lipunov et al., GCN 27706, Kuin et al., GCN 27709) with 0.7m GROWTH-India telescope. We obtained a 550 sec r band exposure starting at UT 2020-05-09T15:04:19. The field was observed at low altitude (< 25 deg). We did not detect any new source up to 19.7 mag within an uncertainty region of 1.7 arcsec (radius, 90% confidence) around RA(J2000) = 07h 45m 41.37s, Dec(J2000) = -04d 37' 49.5" (Evans et al., GCN 27703).
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 27713
Subject
GRB 200509A: Swift-BAT refined analysis
Date
2020-05-10T17:34:13Z (5 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
D. M. Palmer (LANL), 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), T. Sakamoto (AGU),
M. Stamatikos (OSU), E. Troja (NASA/GSFC/UMCP),
T. N. Ukwatta (LANL) (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 200509A (trigger #970886)
(Troja et al., GCN Circ. 27701). The BAT ground-calculated position is
RA, Dec = 116.415, -4.634 deg which is
RA(J2000) = 07h 45m 39.6s
Dec(J2000) = -04d 38' 02.5"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 39%.
The mask-weighted light curve shows a multi-peaked structure that starts
at ~T0 and ends at ~T+850 s. The three prominent peaks occur at ~T0,
~T+600 s, and ~T+820 s, respectively. There might be additional burst
emission beyond the available event data range (i.e., > T+963 s).
T90 (15-350 keV) is 828.2 +- 13.4 sec (estimated error including
systematics).
The time-averaged spectrum from T-0.80 to T+848.99 sec is best fit by a
simple
power-law model. The power law index of the time-averaged spectrum is
1.67 +- 0.09. The fluence in the 15-150 keV band is 7.3 +- 0.4 x 10^-6
erg/cm2.
The 1-sec peak photon flux measured from T+822.69 sec in the 15-150 keV band
is 1.5 +- 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/970886/BA/