GRB 050509A, GRB 050509
GCN Circular 3460
Subject
GRB 050509A: Further I-band imaging
Date
2005-05-23T12:48:28Z (21 years ago)
Edited On
2024-11-18T10:05:25Z (2 years ago)
From
Brian Lindgren Jensen at U.of Copenhagen <brian_j@astro.ku.dk>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
GRB 050509.074: Further I-band imaging
Johan P. U. Fynbo, Brian L. Jensen, Jens Hjorth, Pall Jakobsson,
J. M. Castro Cerón, H. Pedersen, Darach Watson (Niels Bohr Institute),
Tapio Pursimo, Raine Karjalainen, John Telting (Nordic Optical
Telescope), Björn Voss (University of Kiel) report:
"Using StanCAM on the 2.56m Nordic Optical Telescope we have obtained
further I-band imaging of the XRT error circle for GRB 050509.074
(Swift trigger 118707, GCN 3379, 3380) on May 19.17. All sources
detected in our early I-band images from 20 min and 2.5 hr after the
burst (GCN 3389) are also detected in the image from May 19. Our 3-sigma
upper limit on the magnitude of any transient source in the XRT error
circle (except in the eastern part covered by the bright star) is
I=22.5. Images of the field are shown at:
http://www.astro.ku.dk/~brian_j/grb/grb050509.074/
"
GCN Circular 3407
Subject
GRB 050509a: Swift-BAT refined analysis
Date
2005-05-10T16:36:13Z (21 years ago)
From
Louis M Barbier at NASA/GSFC/Swift <lmb@cosmicra.gsfc.nasa.gov>
L. Barbier (GSFC), S. Barthelmy (GSFC), P. Boyd (GSFC-UMBC),
J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
T. Mitani (ISAS) D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/NRC), G. Sato (ISAS), M. Suzuki (Saitama),
J. Tueller (GSFC), W. Voges (MPE)
on behalf of the Swift/BAT team:
At 01:46:28 UT Swift-BAT detected GRB 050509a (trigger=118707)
(GCN Circ 3379, C. Hurkett, et al.). The refined BAT ground position
is (RA,Dec) = 310.608,+54.059, [deg; J2000] {20:42:24; +54:00:14}
+- 0.45 arcmin, (95% containment). XRT found an uncatalogued
x-ray source 13 arcseconds from the BAT position (GCN Circ 3380,
J. Kennea, et al.) The coding was 100% in the FOV.
The 1-s maskweighted lightcurve shows two distinct peaks. T90 (15-350 keV)
is (11.6 +- 1.0) seconds (estimated error including systematics).
The photon index of the time-averaged spectrum is 2.1 +- 0.2.
The fluence in the 15-350 keV band is (4.6 +- 0.7) x 10^-7 erg/cm2.
The 1-s peak photon flux measured from T0+0.388 second in the 15-350 keV
band is (0.98 +- 0.13) ph/cm2/s. All the quoted errors are at the 90%
confidence level.
GCN Circular 3394
Subject
GRB050509a: Swift UVOT observations
Date
2005-05-09T16:04:32Z (21 years ago)
From
Katie McGowan at MSSL-UCL <km2@mssl.ucl.ac.uk>
T. Poole (MSSL), C. Hurkett (Leicester), S. Hunsberger (PSU), A. Breeveld
(MSSL), P. Boyd (GSFC), N. Gehrels (GSFC), K. Mason (MSSL), J. Nousek
(PSU), on behalf of the Swift UVOT team
The Swift Ultra-Violet/Optical Telescope (UVOT) began observations of
GRB050509a on May 09, 2005 at 01:47:20.5 UT, 52 seconds after the initial
Swift BAT trigger (Hurkett et al., GCN 3379). The XRT error circle
(Kennea et al., GCN 3380) falls partially on a known source from the DSS.
We detect no new sources at the Swift XRT position (Kennea et al, GCN
3380). The limiting magnitudes (in 6" radius apertures) in each of the
UVOT filters are as follows:
Filter Lim_Mag Lim_mag Total duration T_start T_mid
5sigma 3sigma (s) (s) (s)
V 18.23 18.79 191 52 1853
UVW1 18.97 19.52 210 5722 5827
UVM2 20.29 20.84 921 3763 4739
UVOT only observed GRB050509b in V, UVW1 and UVM2 because it's run of
observations were interrupted by GRB050509b.
The magnitudes are based on preliminary zero-points, measured in
orbit, and will require refinement with further calibration.
This message may be cited.
GCN Circular 3389
Subject
GRB 050509A: Optical observations
Date
2005-05-09T09:07:30Z (21 years ago)
Edited On
2024-11-18T07:44:45Z (2 years ago)
From
Johan U. Fynbo at U.Copenhagen <jfynbo@astro.ku.dk>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
GRB 050509A: Optical observations
J. P. U. Fynbo, B. L. Jensen, J. Hjorth, P. Jakobsson,
J. M. Castro Cerón, H. Pedersen, D. Watson (Niels Bohr Institute),
J. Näränen (Nordic Optical Telescope) report:
"Using ALFOSC on the 2.56m Nordic Optical Telescope we have obtained
I-band imaging of the XRT error circle for GRB 050509A (Swift trigger
118707, GCN 3379, 3380) at two epochs starting ~20 min and ~2.5 hr
after the GRB trigger. In the XRT error-circle we detect several
sources. One source is less than 2" from the centre of the XRT error
circle and not seen in the DSS-II (red). The position of this source is:
RA(2000) = 20:42:19.60, Dec(2000) = +54:04:17.8
The source is fainter than the sensitivity of the DSS-II red image and
has an estimated magnitude of I = 21.7 (not corrected for a galactic
extinction of A_I = 1.15 mag). The source does not vary significantly
between the two epochs. An image of the field is shown at:
http://www.astro.ku.dk/~brian_j/grb/grb050509A/
"
GCN Circular 3380
Subject
GRB 050509a: Swift XRT Position
Date
2005-05-09T04:33:55Z (21 years ago)
From
Jamie A. Kennea at PSU/Swift-XRT <kennea@astro.psu.edu>
J. A. Kennea, D. N. Burrows (PSU), C. P. Hurkett, E. Rol (U. Leicester)
and N. Gehrels (NASA/GSFC) report on behalf of the Swift XRT team:
The Swift BAT instrument detected GRB 050509a at 01:46:28 UT on 9th May
2005 (GCN Circ 3379). The observatory executed an automated slew to the
BAT position and the XRT began taking data at 01:47:22 UT. The XRT was in
Auto state but was not able to centroid on the afterglow due to low source
intensity. From downlinked data we find a uncatalogued X-ray source
located at:
RA(J2000) = 20:42:19.7,
Dec(J2000) = +54:04:16.2
We estimate an uncertainty of about 6 arcseconds radius (90% containment).
This position is 13 arcseconds from the BAT position reported in GCN 3379.
GCN Circular 3379
Subject
Swift Detection of the Burst GRB050509
Date
2005-05-09T02:47:54Z (21 years ago)
From
Cheryl Pauline Hurkett at Leicester U <cph9@star.le.ac.uk>
C. Hurkett, E. Rol, (U Leicester), L. Barbier (GSFC), S. Barthelmy (GSFC),
A. Blustin (MSSL), D. Burrows (PSU), J. Cummings (GSFC/NRC),
N. Gehrels (GSFC), J. Kennea (PSU), C. Markwardt (GSFC/UMD), on behalf of
the Swift Team;
At 01:46:28 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB050509 (trigger=118707). The BAT on-board calculated
location is RA, Dec 310.588, +54.070 (J2000) with an uncertainty of 3
arcmin (radius, 3-sigma, including estimated systematic uncertainty).
The BAT light curve shows a single main peak with a small peak on the
rising edge (at T-6sec). The total duration is ~13 sec. The BAT peak
count rate is ~2300 events/sec at T_zero (15-350 keV).
The Swift spacecraft slewed promptly onto the BAT position. The XRT
imaged the field at 01:47:22.76 (54.8s after the burst), but did not find
any bright source in the field. An XRT position will be determined by
analysis of the full data following the next ground station pass.
The Swift Ultra Violet/Optical (UVOT) observations began at
01:47:20.5 UT, 52 seconds after the BAT trigger. The first
data taken after the spacecraft settled was a 90 sec exposure
using the V filter with the midpoint of the observation at
97 sec after the BAT trigger. Based on a preliminary comparison with the
DSS and USNO-B, we detect no new source within the BAT error
circle down to an approximate five sigma limiting magnitude of 17.3.
The observation was truncated by an observing constraint at 01:50:00 UT
after approximately 110 sec.