GRB 090510
GCN Circular 9355
Subject
GRB 090510: Suzaku WAM observation of the prompt emission
Date
2009-05-14T08:52:46Z (17 years ago)
From
Norisuke Ohmori at Miyazaki U <ohmori@astro.miyazaki-u.ac.jp>
N. Ohmori, K. Noda, E. Sonoda, M. Yamauchi, K. Kono, H. Hayashi,
A. Daikyuji, Y. Nishioka (Univ. of Miyazaki),
M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa,
T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
T. Uehara, Y. Hanabata, T. Takahashi, Y. Fukazawa (Hiroshima U.),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
on behalf of the Suzaku WAM team, report:
The short hard GRB 090510 detected by the Fermi-LAT (Swift/BAT trigger
#351588; Hoversten et al., GCN 9331,Fermi-LAT trigger #263607783;
Ohno et al., GCN 9334)
triggered the Suzaku Wide-band All-sky Monitor (WAM)
which covers an energy range of 50 keV - 5 MeV at 00:23:00 UT (=T0).
The observed light curve shows a multi-peaked structure starting at T0-0.1s,
ending at T0+0.9s with a duration (T90) of about 0.33 seconds.
The emissions was clearly detected at least up to 5 MeV.
However, since the incident angle of this burst to the WAM is off-axis, we
cannot perform a reliable spectral analysis at this moment.
We are now improving our detector response from such an off-axis direction.
The light curves for this burst are available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html
GCN Circular 9354
Subject
GRB 090510, Radio limits
Date
2009-05-13T16:00:14Z (17 years ago)
From
Dale A. Frail at NRAO <dfrail@nrao.edu>
D. A. Frail (NRAO) and P. Chandra (RMC) report on behalf of a
larger collaboration:
"We have used the Very Large Array (VLA) to image a field toward the
short, bright Fermi-LAT burst GRB 090510 (GCN # 9350, 9334). The VLA
observed at a frequency of 8.46 GHz on three epochs, May 11.48, May
12.48 and May 13.52 UT. There is no radio source detected at the
position of the optical afterglow (GCN #9340). Adding the data
together for all three epochs, the 3-sigma limit is 84 uJy. No further
observations are planned.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
GCN Circular 9353
Subject
GRB090510: VLT/FORS2 spectroscopic redshift
Date
2009-05-12T17:42:34Z (17 years ago)
From
Arne Rau at MPE <arau@mpe.mpg.de>
Arne Rau (MPE Garching), Sheila McBreen (UCD/MPE Garching), Thomas
Kruehler, and Jochen Greiner (both MPE Garching) report:
We present follow-up optical spectroscopy of the short Swift/Fermi GRB
090510 (Hoversten et al., GCN 9331; Ohno & Pelassa, GCN 9334; Guiriec
et al., GCN 9336) using VLT/FORS2 (PI McBreen). Observations of the
optical source consistent with position of the afterglow (Marshall &
Hoversten, GCN 9332; Olofsson et al., GCN 9338; Olivares et al., GCN
9352) started on May 12 08:17UT. A total of three 30min exposures
with the 300I grism were obtained, covering an approximate wavelength
range of 6000-10000 Angstroms.
Preliminary analysis of the spectra reveals two emission lines at 7093
and 9250 Angstroms, which we identify as [OII] and Hbeta at a common
redshift of z=0.903 +/- 0.003. Furthermore, there are indications of a
spectral break in the continuum around 7600 Angstroms, suggesting a
possible 4000A break at the same redshift.
The detection of emission lines and the possible 4000A break suggest
the dominance of the underlying host galaxy over the afterglow at the
time of our observations. It also confirms that host galaxies of short
GRBs are not all old and dead ellipticals but instead drawn from the
underlying field galaxy distribution (e.g., Berger 2009, ApJ, 690,
231).
In the acquisition image the center of the host is 0.7" offset with
respect to the NOT refined afterglow position, which corresponds to 5.5
kpc at a
z=0.903.
At a redshift of z=0.903, the isotropic equivalent energy of the burst
is 3.8E52 erg in the 1 keV - 10 MeV rest frame (using the Fermi/GBM
spectral parameters of Guiriec et al., GCN 9336). The peak energy of
the best fit GBM Band function model is 8.4 +/- 0.8 MeV in the rest
frame.
We acknowledge excellent support from the ESO staff, in particular
F. Selman and I. Condor.
GCN Circular 9352
Subject
GRB 090510: GROND observations
Date
2009-05-12T15:19:57Z (17 years ago)
From
Thomas Kruehler at MPE/MPI <kruehler@mpe.mpg.de>
F. Olivares (MPE Garching), S. Klose (Tautenburg), T. Kruehler, J. Greiner
(both MPE Garching) report on behalf of the GROND team:
GROND, mounted at the 2.2m on La Silla, observed the field of GRB 090510,
detected by Swift (Hoversten et al., GCN 9331), Fermi GBM (Guiriec et al.,
GCN 9336) and LAT (Ohno & Pelassa, GCN #9334), AGILE (Longo et al., GCN
9343) and Konus-Wind (Golenetskii et al., GCN 9344), in g'r'i'z'JHK
starting at 6:34 UT on 10 May 2009.
We detect the afterglow reported by Marshall & Hoversten (GCN #9332) and
Olofsson et al. (GCN #9338) in the optical bands. At a midtime of 9.0 h
after the burst, we measure the following AB magnitudes of the afterglow
and upper limits in stacked images
g' = 23.5 +/- 0.3
r' = 23.0 +/- 0.1
i' = 22.8 +/- 0.1
z' = 22.6 +/- 0.1
J > 21.8
H > 21.4
K > 20.7
calibrated against the GROND zeropoints and 2MASS field stars. We caution
that the photometry might be contaminated by the nearby source mentioned by
Olofsson et al. (GCN #9338).
Together with the magnitude reported by NOT (Olofsson et al. GCN #9338),
this implies a rapid early fading with an index of ~2 during this epoch,
which is compatible to the X-ray afterglow at a similar time interval
(Grupe & Hoversten, GCN #9341). A late flattening of the optical light
curve is then indicated by the UVOT detection (Kuin et al. #GCN 9351).
GCN Circular 9351
Subject
GRB 090510: Swift/UVOT host galaxy candidates
Date
2009-05-11T23:50:50Z (17 years ago)
From
Paul Kuin at MSSL <npkuin@googlemail.com>
N. P. M. Kuin (MSSL/UCL), S. Oates (MSSL/UCL), M. De Pasquale (MSL/UCL),
E.A. Hoversten (PSU), and F. Marshall (GSFC) report on behalf of the
Swift UVOT team.
The Swift UltraViolet/Optical Telescope (UVOT) continued observations of
the short hard burst GRB 090510 (Swift BAT trigger number 351588;
Hoversten et al. GCN Circ. 9331) today. The summed image in the white
filter taken between 92.7ks and 127.6 ks shows that the source has faded
from the initial magnitude of wh = 18.76 mag at T+800 and is now possibly
detected at 3.3 sigma at a magnitude of 22.9+/-0.3. Observations between
T+2000s and T+100ks show a decay index of about 1. There are also two
nearby sources at the 6 sigma level detectable, which we consider to be
possible hosts of GRB 090510.
The first, nearest, candidate is at position RA, DEC = 333.55220, -26.584525
(22h 14m 12.53s, -26d 35m 04.29s (J2000)), with a diameter of 2.3", and the
second, more extended, candidate is found at position RA, DEC =
333.54963, -26.582294 (22h 14m 11.91s, -26d 34m 56.26s (J2000)), is more
elongated with a diameter of about 3.1". The estimated positional accuracy
is 0.7" for both sources. Both sources have a wh magnitude of 21.61 +/- 0.17.
We encourage follow-up observations.
We would like to make a correction: The UVOT positional error on GRB 090510
quoted in GCN 9342 was too large. The correct uncertainty in the GRB position
was 0.61" (90% confidence radius).
GCN Circular 9350
Subject
GRB 090510: Fermi-LAT follow-up analysis
Date
2009-05-11T21:33:14Z (17 years ago)
From
Nicola Omodei at INFN(Pisa)/GLAST <nicola.omodei@pi.infn.it>
N. Omodei (INFN Pisa), J. Granot (University of Hertfordshire),
P. Meszaros (PSU), J. McEnery (GSFC), F. Piron (LPTA), S. Razzaque (NRL)
H. Tajima (SLAC), V. Vasileiou (GSFC/UMBC), D. Williams (UCSC),
report on behalf of the Fermi LAT Collaboration.
A follow-up analysis of the short bright Fermi GRB 090510 (Ohno et al.,
GCN 9334, Guiriec et al., GCN 9336) has been performed by the Fermi-LAT
team.
Fermi LAT has detected more than 50 events above 100 MeV (>10 above 1
GeV) during the first second and more than 150 events above 100 MeV (>20
above 1 GeV) in the first minute after the GBM trigger.
All these events are positionally consistent (within the 95% containment
radius of the LAT point spread function) with the position reported by
Swift (Goad et al. GCN 9339). They indicate extended emission above GeV
energies, making this burst an absolute priority for follow-up searches,
especially a redshift determination.
The points of contact for this burst is:
Masanori Ohno ohno@astro.isas.jaxa.jp
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 9345
Subject
GRB 090510: correction to GCN 9344
Date
2009-05-11T13:54:52Z (17 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>
V. Pal'shin on behalf of the Konus-Wind team, report:
"...the peak energy E0 = 552(-249, +448) keV (chi2 = 28.6/31 dof)."
in GCN 9344
should be read as:
"...the e-folding energy E0 = 552(-249, +448) keV (chi2 = 28.6/31 dof)."
GCN Circular 9344
Subject
Konus-Wind observation of GRB 090510
Date
2009-05-11T13:37:31Z (17 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind
team, report:
The short hard GRB 090510 (Swift-BAT trigger #351588: Hoversten et al.,
GCN 9331, Ukwatta et al., GCN 9337; Fermi-LAT trigger 263607783 /
090510016: Ohno & Pelassa, GCN 9334) triggered Konus-Wind at T0=1381.547
s UT (00:23:01.547).
The burst light curve shows a multipeaked structure with a duration of
~0.4 s
As observed by Konus-Wind the burst
had a fluence of (2.42 +/- 0.37)x10^-5 erg/cm2,
and a 16-ms peak flux measured from T0+0.002 s
of (2.27 +/- 0.63)x10^-4 erg/cm2/s
(both in the 20 keV - 15 MeV energy range).
The spectrum of the most intense part
(from T0 to T0+0.192 s; it comprises ~75% of the total counts)
is well fitted (in the 20 keV - 15 MeV
range) by GRB (Band) model for which:
the low-energy photon index alpha = 0.11(-0.43, +0.48),
the high energy photon index beta = -1.61(-0.34, +0.15),
the peak energy E0 = 552(-249, +448) keV (chi2 = 28.6/31 dof).
Since beta > -2 we can establish only the lower limit on the peak energy
in the EF(E) spectrum: Ep > 912 keV.
The emission is clearly seen up to the end of the Konus-Wind energy
range at 15 MeV.
All the quoted errors are at the 90% confidence level.
We note that since beta > -2 the bolometric fluence might be
substantially higher than the given value.
The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090510_T01381/
[GCN OPS NOTE(11may09): The typo in the Subject-line was changed from "091005"
to "090510".]
GCN Circular 9343
Subject
AGILE detection of GRB 090510
Date
2009-05-10T19:38:52Z (17 years ago)
From
Marco Feroci at IASF/INAF <sa.grb@iasf-roma.inaf.it>
F. Longo, E. Moretti, G. Barbiellini, E. Vallazza (INFN Trieste),
A. Giuliani (INAF/IASF Milan), S. Cutini, C. Pittori (ASDC) M.
Marisaldi, A. Bulgarelli, F. Gianotti, M. Trifoglio, G. Di Cocco,
C. Labanti, F. Fuschino, M. Galli (INAF/IASF Bologna),
A. Chen, S. Mereghetti, F. Perotti, P. Caraveo (INAF/IASF Milan),
Y. Evangelista, E. Del Monte, M. Feroci, I. Donnarumma, L. Pacciani, P.
Soffitta, E. Costa, F. Lazzarotto, I. Lapshov, M. Rapisarda(INAF/IASF
Rome), A. Pellizzoni, M. Pilia (INAF/OA Cagliari), S. Vercellone
(INAF/IASF Palermo),
M. Tavani, G. Pucella, F. D'Ammando, V.Vittorini, A. Argan, A. Trois,
G. Piano, S. Sabatini (INAF/IASF Rome), P. Picozza, A. Morselli (INFN
Roma-2), M. Prest (Universita` dell'Insubria), P. Lipari, D. Zanello
(INFN Roma-1), A. Rappoldi, P. Cattaneo (INFN Pavia) and P. Giommi,
P. Santolamazza,
F. Verrecchia (ASDC) and L. Salotti (ASI), on behalf of the AGILE Team,
report:
AGILE detected the remarkable short GRB 090510 (Hoversten et al. GCN
#9331, Ohno et al. GCN #9334) at approximately 61 degrees off-axis.
An analysis of AGILE-GRID data shows an above 5-sigma detection of
gamma-ray emission above 100 MeV. The gamma-ray lightcurve above 100 MeV
shows emission during both the prompt phase and during a "delayed" phase.
Also the Mini-Calorimeter detected a very significant and structured
event lasting ~200 msec with emission well above 3 MeV.
The burst triggered also SuperAGILE, although outside the field of view.
This is the first short GRB with emission above 100 MeV detected by AGILE.
GCN Circular 9342
Subject
GRB 090510: UVOT refined analysis
Date
2009-05-10T16:59:54Z (17 years ago)
From
Paul Kuin at MSSL <npkuin@googlemail.com>
N. P. M. Kuin (MSSL/UCL) and E.A. Hoversten (PSU) report on
behalf of the Swift UVOT team.
The Swift UltraViolet/Optical Telescope (UVOT) began observations of
the short hard burst GRB 090510 (Swift BAT trigger number 351588;
Hoversten et al. GCN Circ. 9331) on May 10, 2009, at 00:24:24 UT,
80 seconds after the BAT trigger with a settling exposure in the
UVOT v filter.
A new optical source was found by the UVOT (Marshall and Hoversten,
GCN Circ. 9332) for which we have a refined position (based on
matching the UVOT field sources to the USNO-B1 catalogue) of
RA, DEC = 333.55208, -26.58311, which is equivalent to:
RA = 22:14:12.5, DEC = -26:34:59.2, with an uncertainty of 1.5"
(90% confidence). The refined UVOT position is offset 1.6" from
the refined XRT position (Goad et al., GCN Circ. 9339) and is
consistent with the revised NOT position (Malesani, GCN Circ. 9340)
to within 0.2".
GRB 090510 is detected in all UVOT filters, except perhaps in b,
which implies that the redshift is less than about 1.5. The
emission is seen to rise to a peak around 600s after the trigger.
The initial magnitude observed in the UVOT filters are given below:
Filter Tstart(s) Tstop(s) Exposure(s) Magnitude
wh 97 247 147.4 19.63 +/- 0.17
wh 588 608 19.5 18.76 +/- 0.22
wh 1167 1526 58.3 19.16 +/- 0.20
v 80 1410 97.3 18.46 +/- 0.33
b 564 1502 97.2 >19.62 (2.2 sigma)
u 712 1477 323.6 19.05 +/- 0.17
uvw1 687 1452 75.9 18.61 +/- 0.27
uvm2 662 1434 93.7s 18.10 +/- 0.22
uvw2 614 1552 115.4s 18.31 +/- 0.18
The values quoted above are on the UVOT Photometric System
(Poole et al, 2008, MNRAS 383,627). They are not corrected for the
expected galactic reddening of E(B-V) = 0.020 in the direction of
the burst (Schlegel et al. 1998).
GCN Circular 9341
Subject
GRB 090510: Swift XRT refined analysis
Date
2009-05-10T15:41:02Z (17 years ago)
From
Dirk Grupe at PSU/Swift-XRT <grupe@astro.psu.edu>
D. Grupe (PSU) and E. Hoversten (PSU) report on behalf of the Swift-
XRT team:
We have analysed XRT data for GRB090510 (Hoversten et al. GCN Circ.
9331) up to
25ks after the burst
beginning 94.1 s after the BAT trigger. The data comprise 200 s in
Windowed
Timing (WT) mode and 9.7 ks in Photon Counting (PC) mode.
The enhanced XRT position for this burst was given by Goad et al.
(GCN. Circ 9339).
The light curve can be modelled with a broken power-law decay with an
index of alpha=0.77+/-0.05, followed by a break at T+1470+/-160 s to
an alpha of 2.16 (+0.17, -0.14).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.57+/-0.08 with an
absorption column consistent with the Galactic
value of 1.66 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum
is consistent with this result.
If the light curve continues to decay with a power-law decay index of
2.16,
the count rate at T+24 hours will be 1.3e-4 counts/s, corresponding to
an
observed 0.3-10 keV flux of 6.1 x 10^-15 erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00351588.
This circular is an official product of the Swift-XRT team.
GCN Circular 9340
Subject
GRB 090510: correction to coordinates in GCN 9338
Date
2009-05-10T14:32:45Z (17 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@astro.ku.dk>
D. Malesani (DARK/NBI) reports:
The coordinates of the afterglow reported in GCN 9338 (Olofsson et al.)
are wrong. The correct ones (referenced to USNO-B1 stars, 0.3" error) are:
RA(J2000) = 22:14:12.56
Dec(J2000) = -26:34:59.0
These coordinates are 0.7" away from the UVOT position (Marshall &
Hoversten, GCN 9332) and indeed consistent within their quoted error.
The object identified in the finding chart posted at
http://www.astro.ku.dk/~malesani/GRB/090510/090510_finder.png
is correctly the afterglow.
I thank Frank Marshall for pointing out the mistake, and regret for any
confusion that this may have created. No blame should go to the other
co-authors of GCN 9338.
GCN Circular 9339
Subject
GRB 090510: Enhanced Swift-XRT position
Date
2009-05-10T10:59:39Z (17 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1675 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 090510, 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 = 333.55271, -26.58266 which is equivalent
to:
RA (J2000): 22h 14m 12.65s
Dec (J2000): -26d 34' 57.6"
with an uncertainty of 1.4 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, arXiv:0812.3662).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 9338
Subject
GRB 090510: NOT afterglow confirmation
Date
2009-05-10T10:30:19Z (17 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@astro.ku.dk>
G. Olofsson, M. Ergon (Univ. Stockholm), D. Malesani, J.P.U. Fynbo
(DARK/NBI), P. Jakobsson (Univ. Iceland), N.R. Tanvir, K. Wiersema
(Univ. Leicester), A.J. Levan (Univ. Warwick), report on behalf of a
larger collaboration:
We observed the field of short Swift/Fermi GRB 090510 (Hoversten et al.,
GCN 9331; Ohno & Pelassa, GCN 9334; Guiriec et al., GCN 9336) with the
Nordic Optical Telescope equipped with ALFOSC. Observations were carried
out in twilight and at high airmass (~3).
The candidate afterglow (Marshall & Hoversten, GCN 9332) is clearly
detected in a stack of our images taken at a mean epoch May 10.215 UT
(4.7 hr after the GRB). Calibrating against closeby USNO stars (R1
magnitudes), we get R ~ 21.2. Comparing this value with the magnitude
reported by Marshall & Hoversten (GCN 9332) indicates fading, thus
confirming that this object is the afterglow of GRB 090510.
Astrometry of the field yields the following coordinates for the
afterglow (0.4" error):
RA(J2000) = 22:14:12.64
Dec(J2000) = -26:35:02.8
which is consistent with the UVOT position. We note the presence of a
fainter source ~1" East of the afterglow. A finding chart is posted at
the following URL:
http://www.astro.ku.dk/~malesani/GRB/090510/090510_finder.png
We acknowledge the observiers at the NOT for carrying out this difficult
observation.
[GCN OPS NOTE(10may09): The authors point out that there is a correction
to the coordinates given above (see GCN Circ 9340).]
GCN Circular 9337
Subject
GRB 090510: Swift-BAT refined analysis
Date
2009-05-10T06:08:40Z (17 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
T. N. Ukwatta (GWU) S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
E. A. Hoversten (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),
D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC)
(i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090510 (trigger #351588)
(Hoversten, et al., GCN Circ. 9331). The BAT ground-calculated position is
RA, Dec = 333.552, -26.598 deg, which is
RA(J2000) = 22h 14m 12.6s
Dec(J2000) = -26d 35' 51.1"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 16%.
The mask-weighted light curve shows a small precursor peak at ~T-0.54 sec
(width ~ 30 msec). Then the main peak starts at ~T-0.05 sec, peaks at T+0.04 sec
with a width of ~50 msec. Then come two smaller peaks at T+0.24 and T+0.32 sec,
each about 40 msec in width. At the 3-sigma level, there is the possibility
of low-level emission between T+110 sec to ~T+170 sec. T90 (15-350 keV)
is 0.3 +- 0.1 sec (estimated error including systematics).
The time-averaged spectrum from T+0.0 to T+0.4 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
0.98 +- 0.20. The fluence in the 15-150 keV band is 3.4 +- 0.4 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.30 sec in the 15-150 keV band
is 9.7 +- 1.1 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/351588/BA/
GCN Circular 9336
Subject
GRB 090510: Fermi GBM detection
Date
2009-05-10T05:46:27Z (17 years ago)
From
Sylvain Guiriec at UAH <sylvain.guiriec@lpta.in2p3.fr>
S. Guiriec, V. Connaughton and M. Briggs (UAH)
report on behalf of the Fermi GBM Team:
"At 00:22:59.97 UT on 2009 May 10, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090510 (trigger 263607781 / 090510016) which
was also detected by the Swift-BAT (Hoversten et al. 2009, GCN 9331) and
the Fermi-LAT (Ohno et al. 2009, GCN 9334).
The GBM position is consistent with those reported by Swift and the LAT.
The GBM triggered on a precursor lasting 30 ms followed 0.4 s later by an
intense and hard emission period of 0.5 s and a tail lasting
a further 0.5 s. The intense period has several narrow peaks and
its integrated spectrum is well fit by a Band function with
alpha = -0.80 +/- 0.03, beta = 2.6 +/- 0.3 and EPeak = 4.4 +/- 0.4 MeV.
The peak flux on a 64 ms timescale between 8 keV and 40 MeV was
measured 0.55 s after the trigger to be 80 ph.cm^-2.s^-1.
The 8 keV to 40 MeV fluence in the 0.512 s long period of intense emission
is (3.0 � 0.2) E-5 erg.cm^-2.
The spectral analysis results presented above are preliminary;
further analysis is on-going."
GCN Circular 9334
Subject
Fermi LAT detection of GRB 090510
Date
2009-05-10T04:26:20Z (17 years ago)
From
Masanori Ohno at ISAS/JAXA <ohno@astro.isas.jaxa.jp>
Masanori Ohno(ISAS/JAXA), Veronique Pelassa(CNRS/IN2P3/LPTA) report
on behalf of the Fermi LAT team:
At 00:23:01.22 UT on 10 May 2009, the Fermi Large Area Telescope (LAT) triggered and located GRB 090510 (trigger 263607783 / 090510016).
Emission was observed in the LAT up to GeV energy band with a detection significance of more than 5 sigma.
The best LAT on-board localization is found to be
(RA,Dec=333.400, -26.767) with an error radius of 7 arcmin (statistical only).
This position is consistent with both Fermi/GBM and Swift/XRT position.
Further analysis is ongoing.
We suggest follow up observation for this burst.
The points of contact for this burst is
Masanori Ohno ohno@astro.isas.jaxa.jp
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.
This message can be cited.
GCN Circular 9332
Subject
GRB 090510: Swift/UVOT Detection of a Candidate Optical Afterglow
Date
2009-05-10T01:26:57Z (17 years ago)
From
Frank Marshall at GSFC <marshall@milkyway.gsfc.nasa.gov>
F. E. Marshall (GSFC) and E. A. Hoversten (PSU) report on behalf of the
Swift team:
UVOT took a second finding chart exposure of 250 seconds with the U filter starting
309 seconds after the BAT trigger for GRB 090510 (Hoversten et al.
GCN Circ. 9331). There is a candidate afterglow in the
rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 22:14:12.54 = 333.55227
DEC(J2000) = -26:34:58.4 = -26.58290
with a 90%-confidence error radius of about 0.69 arc sec. This position is 0.7
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.95 with a 1-sigma error of about 0.17. No information about
variability is available at this time. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.02.
GCN Circular 9331
Subject
GRB 090510: Swift detection of a short hard burst
Date
2009-05-10T00:41:41Z (17 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
E. A. Hoversten (PSU), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
M. M. Chester (PSU), D. Grupe (PSU), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (MSSL),
D. M. Palmer (LANL) and T. N. Ukwatta (GSFC/GWU) report on behalf of
the Swift Team:
At 00:23:00 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090510 (trigger=351588). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 333.555, -26.606 which is
RA(J2000) = 22h 14m 13s
Dec(J2000) = -26d 36' 19"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows a single spike
with a duration of about 0.5 sec. The peak count rate
was ~21000 counts/sec (15-350 keV), at 0 sec after the trigger.
The XRT began observing the field at 00:24:34.6 UT, 94.1 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 333.55195, -26.58345 which is
equivalent to:
RA(J2000) = 22h 14m 12.47s
Dec(J2000) = -26d 35' 00.4"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 81 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 http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
1.66e+20 cm^-2 (Kalberla et al. 2005).
UVOT took a finding chart exposure of 150 seconds with the White
filter starting 97 seconds after the BAT trigger. No credible
afterglow candidate has been found in the initial data products.
The 2.7'x2.7' sub-image does not include the position of the XRT
candidate. The 8'x8' region for the list of sources generated
on-board covers the XRT position and 100% of the BAT 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 0.02.
We note the existence of the galaxy 2dFGRS TGS176Z296 at
a distance of 140 arcsec from the XRT position.
Burst Advocate for this burst is E. A. Hoversten (hoversten AT astro.psu.edu).
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/too.html.)