GRB 990907
GCN Circular 404
Subject
BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
Date
1999-09-07T22:31:37Z (26 years ago)
From
Luigi Piro at IAS/CNR Frascati <piro@alpha1.ias.rm.cnr.it>
Giangiacomo Gandolfi, on behalf of BeppoSAX Mission Scientist, reports:
A GRB (GB990907) was detected by the GRBM and WFC of BeppoSAX on Sep.7,
around 17:34 U.T.
Preliminary coordinates from WFC are:
R.A.(2000)=112.552
DEC(2000)=-69.394
Due a less-than-optimal attitude configuration the error radius is about 8'.
GCN Circular 405
Subject
GRB990907: refined WFC position
Date
1999-09-08T03:02:55Z (26 years ago)
From
Luigi Piro at IAS/CNR Frascati <piro@alpha1.ias.rm.cnr.it>
Giangiacomo Gandolfi, on behalf of BeppoSAX Mission Scientist, reports:
GRB990907: refined WFC position
Date: Sept.7, 1999, 17:34 UT
The refined WFC position of GRB990907 is:
R.A. = 112.699 degrees
Decl. = -69.406 degrees
(equinox 2000)
The error radius is 6'.
We are planning a follow-up with NFI.
GCN Circular 407
Subject
IPN localization of GRB990907
Date
1999-09-09T23:28:08Z (26 years ago)
From
Kevin Hurley at UCBerkeley/SSL <khurley@sunspot.ssl.berkeley.edu>
K. Hurley, on behalf of the Ulysses GRB team, and M. Feroci, on behalf
of the BeppoSAX GRB team, report:
We have obtained a preliminary IPN annulus for GRB990907 (GCN 405). This
annulus is centered at RA=156.6738 deg., Decl.=-13.6899 deg. (J2000),
and has a radius of 62.1237 +/- 0.080 deg. (3 sigma). It intersects the
BeppoSAX NFI error circle (GCN 373) to form an ~100 arcmin.^2 error
box whose corners are:
RA(2000) Decl.(2000)
07h 30m 37.7s -69o 30' 18"
07h 29m 39.6s -69o 24' 14"
07h 31m 55.0s -69o 23' 22"
07h 31m 09.7s -69o 18' 41"
A map may be found at ssl.berkeley.edu/ipn3/990907/. Only minor
refinements to this annulus are expected.
GCN Circular 408
Subject
GRB990907 and 990908
Date
1999-09-10T20:55:50Z (26 years ago)
From
Brian Schmidt at Res. School of Astro.and Astrophbrian@mso.anu.edu.au <brian@mso.anu.edu.au>
Tim Axelrod, Jeremy Mould and Brian Schmidt (The Research School of
Astronomy and Astrophysics, The Australian National University) report
the following observations of GRB990907 and GRB990908.
We have imaged the position of both GRB990907 and GRB990908 with the
Mount Stromlo 50inch telescope + macho camera at multiple epochs in
approximately 2.4" seeing. A differential image analysis of an area
21'x21' around the BeppoSAX position of GRB990907 (GCN 405) from two
images taken 1999 Sep 8.56 and 1999 Sep 9.60 shows no variable sources
with residuals brighter than a magnitude of m_v=20.3. A similar analysis
of a 21'x21' field centered on the BeppoSAX position of GRB990908
(GCN 406) from images taken 1999 Sep 8.48 and 1999 Sep 9.59 shows a single
variable stellar object (mag approx 18), fading by 0.3 magnitudes,
present at both epochs, and present on the Digital Sky Survey (RA:
06:51:10.52 DEC: -75:02:17.3 J2000). This object is most likely a short
period variable star within our own galaxy, but due to our
poor seeing conditions, it is possible the host could be a compact
galaxy, and is therefore worthy of further investigation. No other sources
were seen with residuals brighter than m_v=20.3.
GCN Circular 409
Subject
GRB990907: BeppoSAX follow up and X-ray afterglow
Date
1999-09-15T17:48:07Z (26 years ago)
From
Luigi Piro at IAS/CNR Frascati <piro@alpha1.ias.rm.cnr.it>
L. Piro (IAS/CNR), M. Capalbi, R. Ricci (BeppoSAX SDC), M. Dadina
(IAS/CNR & BeppoSAX SOC), L. Di Ciolo (BeppoSAX SOC), C. De Libero
(BeppoSAX OCC), R.C. Butler (ASI) report:
A BeppoSAX follow-up observation of GRB990907 (GCN 405)
started on Sept. 8, 4:32 U.T. Due to technical problems the observation
lasted 20 minutes only, with an exposure time of 1070 s. in the
MECS(1.6-10 keV). A previously unknown X-ray source 1SAXJ0731.2-6928
is detected within the WFC error box with a MECS count rate of
(2.0+/-0.6)x10^-2 cts/s.
The position (equinox 2000) is R.A.=7h 31m 12 s Decl=-69 28' 10", i.e.
4' away from the center of the WFC position (GCN405).
Due to the vicinity of the source to the support grid of the detector
we estimate an error of 3' in radius and a flux (2-10 keV) between 1 and
2 x 10^-12 erg/cm^2/s. The probability that a serendipitous source
with similar strength is found in the WFC error circle is about 3x10^-3.
We conclude that 1SAXJ0731.2-6928 is likely the X-ray afterglow of GRB990907.
GCN Circular 413
Subject
Optical Observations of GRB990907
Date
1999-09-23T12:41:05Z (26 years ago)
From
Nicola Masetti at ITeSRE,CNR,Bologna <masetti@tesre.bo.cnr.it>
Optical Observations of GRB990907
E. Palazzi, E. Pian, N. Masetti, F. Frontera (ITESRE, CNR, Bologna),
P.M. Vreeswijk, E. Rol (U. of Amsterdam), H. Pedersen, J. Hjorth (CUO,
Copenhagen), J. van Paradijs (U. of Amsterdam and U. of Alabama in
Huntsville), C. Kouveliotou (NASA-MSFC/USRA), P. Leisy, A. Pizzella,
E. Pompei (ESO-La Silla), R. Mennickent (Univ. de Concepcion, Chile),
C.G. Tinney, F. Freeman, S. Lee, J. Hawthorn (AAO), R. McMahon, S. Maddox,
C. Singleton (IoA, Cambridge), and H. Jones (RSAA), on behalf of the
BeppoSAX and Amsterdam/Huntsville GRB optical follow-up teams, report:
"We obtained V band images of the GRB 990907 field (GCN #405 and
GCN #409) at the Anglo Australian Telescope with Taurus + MITLL2,
at the ESO 1.54m Danish telescope with DFOSC, and at the ESO VLT telescope
with FORS1, beginning 24.9 hrs after the GRB event. Images in other bands
(R and I) were also acquired as detailed in the following table:
Telescope Date (UT) Filter Exptime Limit mag. Seeing
(3-sigma)
AAT Sep 8.7698 V 480 sec 23.2 1".4
Danish Sep 9.3736 V 1600 sec 23.0 2".6
Danish Sep 9.3755 R 1600 sec 23.0 2".6
Danish Sep 9.3854 I 1600 sec 22.5 3".5
AAT Sep 10.7806 V 800 sec 22.7 2".8
VLT Sep 10.4111 V 180 sec 23.5 1".1
VLT Sep 10.4153 R 180 sec 23.6 1".1
AAT Sep 18.3736 V 960 sec 23.2 2".2
Photometric calibration was done using standard stars in the Landolt
field PG0231+051. Comparisons were made among the V, R, and I band
images with the Digital Sky Survey, between the two R and among the
five V frames taken at different epochs.
The comparison does not show any object with significant brightness
variations larger than 0.3 mag.
This message can be cited."
GCN Circular 415
Subject
GRB 990907 optical observations
Date
1999-09-26T09:08:01Z (26 years ago)
From
Alberto Castro-Tirado at LAEFF-INTA <ajct@laeff.esa.es>
GRB 990907, optical observations
--------------------------------------
Javier Gorosabel, LAEFF-INTA (Madrid)
Alberto Castro-Tirado, LAEFF-INTA (Madrid) and IAA-CSIC (Granada)
Ian Bond, Nick Rattembury and Phil Yock, University of Auckland
Pam Kilmartin, University of Canterbury
T. Sumi (Japan)
Hernan Muriel, IATE (Cordoba)
Enrico Costa, IAS (Frascati), on behalf of the BSAX team
report:
"We have obtained three 10-minute exposures of the BeppoSAX
position of GRB 990907 (Gandolfi et al. GCN 404, 405) with the
0.61-m Mount John University Observatory (MJUO) telescope.
The images were taken on Sep 9.40 UT through a broad band filter
(R + I bandpass). After a visual comparison with the Digital Sky
Survey, no sources varying by more than 0.3 mag were seen to the
DSS-2 limit within the BSAX NFI error box (GCN 409) in agreement
with the negative results provided by Palazzi et al. (GCN 413)."