GRB 980519
GCN Circular 74
Subject
GRB980519, BeppoSAX-WFC position
Date
1998-05-19T17:02:00Z (27 years ago)
From
Luigi Piro at IAS/CNR Frascati <piro@alpha1.ias.rm.cnr.it>
Luigi Piro on behalf of the BeppoSAX team report:
GB980519 (BATSE trigger n.6764) has been detected by the GRBM of BeppoSAX
and by the WFC at about 12:20:00 UT of May 19.
A preliminary position by the WFC is:
RA(2000)=350.54
Dec(2000)=77.293
with an error radius of 5'.
A BeppoSAX follow up with the NFI is being planned.
GCN Circular 75
Subject
GRB980519, BeppoSAX-WFC updated position
Date
1998-05-19T17:19:24Z (27 years ago)
From
Luigi Piro at IAS/CNR Frascati <piro@alpha1.ias.rm.cnr.it>
Luigi Piro on behalf of the BeppoSAX team report:
GB980519 (BATSE trigger n.6764) was detected by the GRBM of BeppoSAX
and by the WFC at about 12:20:00 UT of May 19.
Refined position from the WFC are:
RA(2000)=350.561
Dec(2000)=+77.255
with an error radius of 3'.
This is 2' from the preliminary position.
[GCN Operator's Note: Due to an unfortunate and rare scheduling conflict
at the GCN end, the original position notice was closely spaced in time
with this updated position notice.]
GCN Circular 78
Subject
GRB980519 optical observations
Date
1998-05-20T02:46:49Z (27 years ago)
From
Jens Hjorth at NORDITA <jens@nordita.dk>
The Nordic Optical Telescope GRB team (A. O. Jaunsen, J. Hjorth, M. I. Andersen,
K. Kjernsmo, H. Pedersen, E. Palazzi) reports the detection at the 2.5-m NOT of
an unresolved (in seeing of 1.5"-2"), variable object located within the
BeppoSAX error box of GRB 980519 (GCN #75).
The coordinates (+- 0.5") are
RA(2000) = 23 22 21.46
Dec(2000) = +77 15 43.0
The object had an I magnitude of about 19.5 on May 19.87 UTC but is not
detected in the DSS while objects of similar magnitude are. The OT had
faded by about 0.6 mag in V and I on May 20.0 UTC.
These observations suggest that the OT is the optical counterpart of GRB 980519.
Preliminary Cousins I photometry (+-0.1 mag, not corrected for extinction) of
4 nearby reference stars yields
RA(2000) Dec(2000) I
A 23 22 17.74 +77 15 51.2 19.04
B 23 22 27.29 +77 15 43.5 19.49
C 23 22 28.50 +77 15 25.4 18.52
D 23 22 47.14 +77 16 23.5 15.69
On this system the OT had I=20.08 on May 20.00 UTC
Finding charts, images and updates will be posted at
http://www.uio.no/~ajaunsen/grb980519
This note can be cited.
GCN Circular 79
Subject
GRB 980519 Optical Observations
Date
1998-05-20T12:35:45Z (27 years ago)
From
George Djorgovski at Caltech/Palomar <george@oracle.caltech.edu>
GRB980519 Optical Observations
S. G. Djorgovski, R. R. Gal, S. R. Kulkarni, J. S. Bloom, and A. Kelly,
on behalf of the Caltech GRB Collaboration, report:
"We obtained multicolor (BVRri) CCD images of the field of GRB 980519
(see GCN Circ. 75), using Palomar Observatory 200-inch and 60-inch
telescopes, on UT May 20.
We confirm the optical transient (OT) discovered by Jaunsen et al.
(GCN Circ. 78). The object is continuing to fade. Using the magnitudes
of stars B and C of Jaunsen et al. (their star A gives discrepant results)
to tie in the instrumental magnitude systems, we derive for the OT:
I = 21.46 (+- 0.1) in this magnitude system, on UT May 20.436 (mean epoch).
Comparing with the value of I = 20.08 mag in the same system on UT May 20.00
from Jaunsen et al., we derive the power-law decline slope of -1.98 for the
I-band light curve. This is fully consistent with the relative V-band
light curve given at http://www.uio.no/~ajaunsen/grb980519.
These measurements are preliminary. A more detailed analysis of the data
is in progress.
This note can be cited."
GCN Circular 80
Subject
GRB980519 Optical Observations
Date
1998-05-20T15:11:30Z (27 years ago)
From
Jules Halpern at Columbia U. <jules@astro.columbia.edu>
The MDM Observatory GRB team (J. Kemp, J. Halpern) reports followup
photometry of the variable optical candidate discovered by Jaunsen et al.
(GCN #78) in the BeppoSAX error box of GRB 980519. In a series of CCD
images taken with the MDM 1.3m telescope, centered around May 20.31 UT,
the candidate had I=20.1+/-0.3, R=20.9+/-0.2. These magnitudes were
measured differentially with respect to stars A, B, and C of Jaunsen et
al., which we recalibrated using Landolt standards. Preliminary
photometry of those reference stars is as follows:
RA(2000) Dec(2000) R I
A 23 22 17.74 +77 15 51.2 17.93 17.28
B 23 22 27.29 +77 15 43.5 (19.26) (18.56)
C 23 22 28.50 +77 15 25.4 18.15 17.43
Parentheses indicate values that are less certain. Note the large
discrepancy between our I-band measurements and those of Jaunsen et al.;
the latter may instead refer to the V band.
MDM images will be posted at http://cba.phys.columbia.edu/jonathan/grb/.
This note can be cited.
GCN Circular 81
Subject
GRB980519 IPN POSITION
Date
1998-05-20T17:01:26Z (27 years ago)
From
Kevin Hurley at UCBerkeley/SSL <khurley@sunspot.ssl.berkeley.edu>
The position of this burst has been obtained by triangulation using
Ulysses and BATSE preliminary data. It is described by an annulus
centered at RA(2000)=329.485, Dec(2000)=-11.873, whose radius is
89.981 degrees, and whose total width is 4.9 arcminutes. This
annulus intersects the refined SAX WFC error circle (BeppoSAX GRB
Mail No. 98/16) and is consistent with the position of the optical transient
reported by J. Hjorth (GCN 78). A figure may be found at
http://ssl.berkeley.edu/ipn3/980519. Processing with the final
data is expected to improve this position.
This message is citeable.
GCN Circular 82
Subject
GRB980519 Optical Observations
Date
1998-05-20T19:55:36Z (27 years ago)
From
Eric Deutsch at U.Washington <deutsch@astro.washington.edu>
On behalf of the Apache Point Observatory GRB team, A. Diercks & C.
Stubbs observed with the APO 3.5m telescope the optical transient (OT)
discovered by Jaunsen et al. (GCN #78) in the BeppoSAX error box of GRB
980519. Conditions were mostly cloudy with roughly 1.8 arcsec seeing.
Photometry by E. Deutsch & A. Diercks on a 1 hr series of images
centered around May 20.44 UT yields the following magnitudes and
relative uncertainties for the OT and reference stars:
ID R mag RelErr
-- ----- -----
OT 21.20 0.03
A 17.93 0.01
B 19.31 0.01
C 18.06 0.01
Absolute calibration is based only on R magnitudes of reference stars
reported by Kemp & Halpern (GCN #80). No independent calibration was
possible due to heavy clouds. Our measurement is 0.3 mag fainter than
the earlier observations of Kemp & Halpern (GCN #80).
Images are posted at: http://www.astro.washington.edu/deutsch/grb/grb980519/
This note can be cited.
GCN Circular 83
Subject
GRB980519 Optical Observations
Date
1998-05-20T23:16:27Z (27 years ago)
From
Fredrick J Vrba at USNO <fjv@nofs.navy.mil>
GRB980519 Optical Observations
The U. S. Naval Observatory GRB team (F. J. Vrba, B. Canzian, S. E. Levine,
H. H. Guetter, A. A. Henden, C. B. Luginbuhl, J. A. Munn), D. H. Hartmann
(Clemson Univ.), and M. C. Jennings (IGPP, UCR visitor) report follow up
optical photometry of the variable object found by Jaunsen et al. (GCN Report 78)
within the BeppoSAX error circle of GRB980519 (see GCN Report 75). Observations
were obtained with the USNO Flagstaff Station 40-inch telescope between
UT 1998 May 20.143 and 20.328 under the pole and again between UT 1998 May 20.426
and 20.464 when the field could be re-acquired at large hour angle. Four sets of
observations were obtained in the Cousins R filter, two in the Cousins I filter,
and one in the Johnson/Cousins V filter. Each set of observations consisted of
three co-added and dithered images of 10 minutes each. The observations were obtained
through variable cirrus clouds and haze. Preliminary reductions of the R-filter
data by comparing with the magnitudes of stars A, B, and C as given in GCN Report 80
yield:
UT Date R (mag)
1998 May 20.163 20.39 +/- 0.12
20.229 20.77 +/- 0.15
20.287 20.87 +/- 0.13
20.445 21.15 +/- 0.13
The uncertainties reflect both the internal photometry errors and the scatter
in the magnitude offsets to stars A, B, and C. These data are consistent
with the single R magnitudes from the MDM telescope (GCN Report 80) and the APO
3.5-m telescope (GCN Report 82). The lightcurve derived from these combined
datapoints can be found on our web site at:
http://psyche.usno.navy.mil/nofs/grb/grb980519.html.
During this time interval the data do not appear to be consistent with a simple
power law decrease in brightness.
In a more detailed analysis we plan to also reduce these data with respect to
two TYCHO stars within our CCD FOV and to analyze the V and I data to investigate
colors.
For further information contact F. J. Vrba at fjv@nofs.navy.mil or by telephone
at (520) 779-5132.
This GCN note can be cited.
GCN Circular 84
Subject
GRB980519 optical observations
Date
1998-05-21T09:17:17Z (27 years ago)
From
Jens Hjorth at NORDITA <jens@nordita.dk>
GRB 980519 Optical Observations
On behalf of the Nordic Optical Telescope GRB team J. Hjorth, A. O. Jaunsen,
K. Kjernsmo, and H. Pedersen report updated as well as new photometry of the
optical transient (Jaunsen et al., GCN #78) believed to be related to
GRB 980519.
As indicated by Djorgovski et al. (GCN #79) and Kemp & Halpern (GCN #80) the
photometry reported in GCN #78 was incorrect. This was due to the strongly
variable, non-photometric conditions prevailing at the time of observations.
Adopting the Kemp & Halpern (GCN #80) zero point the updated photometry of the
OT yields I=18.48+-0.1 on May 19.88 UT and I=19.05+-0.03 on May 20.00 UT.
In the same photometric system we report the following measurements:
May 20.98 UT I=21.64+-0.2
May 21.17 UT I=21.64+-0.1
These measurements are uncertain as the OT is close to the detection limit
in our images.
Thus, the rapid decay has continued during May 20 UT. Our last measurements
provide marginal evidence that the decay has leveled off. If confirmed, this
may be due to non-trivial intrinsic variability of the source or to an extra
source of light along the line of sight to the OT, eg. the host galaxy.
The above findings are preliminary. A more detailed analysis of the data
is in progress.
This note can be cited.
GCN Circular 86
Subject
GRB980519 BATSE Observations
Date
1998-05-21T18:33:07Z (27 years ago)
From
Valerie Connaughton at MSFC <vc@coltrane.msfc.nasa.gov>
V. Connaughton (National Research Council and NASA Marshall Space Flight
Center) reports on behalf of the BATSE GRB team:
GRB980519 (GCN 74) was detected by BATSE on May 19.51403 as trigger
6764. The event lasted about 60 seconds and was seen as a series of
spikes riding on a single pulse for the first 20 seconds, followed by a
gradual decay. A peak flux of 6.94 +/- 0.25 photons cm^-2 s^-1 between
50 and 300 keV, integrated over 64 ms, places it in the brightest 12%
of BATSE bursts. The fluence above 25 keV is
2.54 +/- 0.41 x 10^-5 erg cm^-2. The location is consistent with the
BeppoSAX-WFC position in GCN 74 & 75. A light curve of the event can
currently be obtained by e-mail from me at vc@msfc.nasa.gov, or will be
available next week at http://www.batse.msfc.nasa.gov/~kippen/batserbr/
when the BATSE Web server is back in operation.
This message is citeable.
GCN Circular 87
Subject
GRB 980519 Optical Observations
Date
1998-05-22T00:47:18Z (27 years ago)
From
Josh Bloom at CIT <jsb@astro.caltech.edu>
GRB 980519 Optical Observations
J. S. Bloom, S. G. Djorgovski, R. R. Gal, S. R. Kulkarni, and
A. Kelly, on behalf of the Caltech GRB Collaboration, report:
"We obtained CCD images of the field of GRB 980519 using COSMIC on the
Palomar Observatory 200-inch on UT May 20. In particular, we imaged the
GRB field for 500 s (Cousins R) and 600 s (Gunn i). We photometrically
calibrated our Gunn i-band and Cousins R-band images against standard
Landolt 1992 (AJ 104, 340) stars (in SA 113). We accounted for atmosphere
extinction and included a color correction term in the fit to account for
the fact that Landolt reports magnitudes in a different R and I band
system. Derived magnitudes of the following 10 secondary stars are thus in
the Londolt RI system (we kept the naming the convention of Jansen et al.
GCN 78):
Object RA DEC I_landolt err R_landolt err
A 23:22:20.0 +77:15:52 17.34 +/- 0.05 17.94 +/- 0.05
B 29.6 44 18.64 +/- 0.05 19.41 +/- 0.05
C 28.7 26 17.57 +/- 0.05 18.10 +/- 0.05
E 20.6 24 18.85 +/- 0.05 20.19 +/- 0.06
F 31.8 45 18.48 +/- 0.05 19.91 +/- 0.06
G 33.2 +77:14:59 17.25 +/- 0.05 19.02 +/- 0.05
H 20.7 14:55 18.13 +/- 0.05 19.44 +/- 0.05
I 09.2 +77:15:51 19.27 +/- 0.06 19.80 +/- 0.06
J 07.6 +77:16:01 19.05 +/- 0.06 20.08 +/- 0.06
L 35.0 16:15 18.57 +/- 0.05 19.21 +/- 0.05
Uncertainty in optimum aperture size for each star is the dominate source
of statistical error. There is an overall zero-point systematic error (not
included above) in each band which amounts to 0.150 mag (I) and 0.151 (R).
The approximate RA and DEC are measured in J2000 from the Digital Sky
Survey (DSS).
We note our derivation for A,B, and C magnitudes are highly discrepant
from that of Jansen et al. GCN #78, but agree quite well with that of Kemp
and Halpern (GCN #80) and Diercks et al. (GCN #82). At the time of
observations we find the OT has magnitudes of May 20.43 UT, I_landolt =
20.86 +/- 0.11; May 20.48 UT, R_landolt = 21.57 +/- 0.09.
A finding chart with the secondary stars noted may be found at
http://astro.caltech.edu/~jsb/grb980519.ps
This message may be cited."
GCN Circular 88
Subject
GRB980519 optical observations
Date
1998-05-22T22:19:07Z (27 years ago)
From
Roy Gal at CalTech <rrg@astro.caltech.edu>
GRB980519 Optical Observations with Keck and Palomar
R. R. Gal, J. S. Bloom, C. Steidel, K. L. Adelberger, S. G. Djorgovski,
and S. R. Kulkarni, on behalf of the Caltech GRB Collaboration, report:
"We have obtained additional photometric CCD images of the field of
GRB 980519. C. Steidel and K. Adelberberger have obtained 11 minutes of
R-band data using the W.M. Keck Observatory 10-m, and R. Gal has
obtained
800 sec. of i band data and 750 sec. of R band data with the Palomar
Observatory 5-m on UT May 21. We measured magnitudes for the OT using
the
Landolt magnitude system derived by Bloom et al.(GCN #87) for the nearby
stars. The OT is no longer visible in our i-band data, with an upper
limit of
I > 21.6 +/- 0.7, at UT May 21.43. The OT is still seen in the R band
with
R = 23.48 +/- 0.2 at UT May 21.469 (Palomar) and R = 23.10 +/- 0.13 at
UT May 21.6 (Keck). The fainter Palomar magnitude at the earlier epoch
is
likely due to poor seeing conditions (>2") which place the object close
to
our detection limit.
C. Steidel and K. Adelberger also report that in seeing conditions
of 0.75" at Keck the OT is not distinguishable from a point source.
We note that these observations place an upper limit on the magnitude of
the
OT host galaxy of not brighter than R ~ 24 mag.
Our R-band magnitudes are consistent with the source still fading with a
slope
of approximately 2.0, while the I-band data do not provide additional
constraints on the slope.
This message may be cited."
GCN Circular 89
Subject
GRB 980519
Date
1998-05-22T22:21:24Z (27 years ago)
From
Dale A Frail at NRAO <dfrail@nrao.edu>
D. A. Frail, G. B. Taylor (NRAO), S. R. Kulkarni (Caltech), and
the BeppoSAX GRB team report:
Beginning on May 19.8, May 20.6 and May 22.3 UT we observed the field
containing the fading X-ray source 1SAX J2322.3+7716 (Nicastro et
al. IAUC 6912) with the VLA at 8.3 GHz. The May 22.3 UT observations
detected a 102+/-19 microJy radio source coincident with the optical
transient first seen by Jaunsen et al. (GCN 78). The radio source VLA
J2322+7715 is at ra = 23h22m21.49s dec = +77d15'43.2" (equinox J2000)
with a conservative error of 0.1 arcsec in each coordinate.
Re-examining this location for the data taken on May 19.8 UT and May
20.6 UT we measure a flux density of 38+/-28 and 68+/-27 microJy,
respectively. We propose that VLA J2322+7715 is the radio afterglow
from GRB 980519. Additional radio observations are in progress to look
for significant variability.
This message may be cited.
GCN Circular 90
Subject
GRB980519 I-band observations
Date
1998-05-22T22:23:30Z (27 years ago)
From
Francisco J Castander at UChicago <fjc@oddjob.uchicago.edu>
GRB980519 I-band observations
F. J. Castander, R. Evans, D. E. Reichart, D. Q. Lamb
and W. Wild, University of Chicago, report:
"We made I-band observations of the BeppoSAX WFC error
circle for GRB980519 (GCN #75) on May 21.34 - 21.36 UT and
May 22.27 - 22.38 UT, using the 41-inch telescope at Yerkes
Observatory. On May 21.35, we detected the optical transient
reported by Jaunsen et al. (GCN #78) at about I = 21.9 mag,
near the limiting magnitude of the image. On May 22.33, we did
not detect the optical transient down to an image limiting
magnituide of I = 21.0 mag. These magnitudes are tied to
the Bloom et al. (GCN #87) calibration standards.
This report may be cited."
GCN Circular 91
Subject
GRB980519 optical observations
Date
1998-05-22T23:19:18Z (27 years ago)
From
Alan Diercks at U.Washington <diercks@astro.washington.edu>
On behalf of the Manastash Ridge Observatory GRB team, A. Diercks &
J. Morgan observed with the MRO 0.76m telescope the optical transient
(OT) discovered by Jaunsen et al. (GCN #78) in the BeppoSAX error box
of GRB 980519. Conditions were cloudy with roughly 3 arcsec seeing.
Photometry by E. Deutsch & A. Diercks on a 12,000s series of images
centered around May 20.4 UT yields the following magnitudes and
uncertainties for the OT and reference objects:
ID R mag RelErr
-- ----- -----
OT 21.07 0.25
A 17.93 0.05
B 19.36 0.08
C 18.06 0.05
Absolute calibration is based only on R magnitudes of reference stars
reported by Bloom et al. (GCN #87). No independent calibration was
possible due to thick clouds. Our measurement is consistent with the
nearly simultaneous R magnitudes reported in GCN #80 and GCN #82.
This note can be cited.
GCN Circular 92
Subject
GRB 980519 Optical Observations
Date
1998-05-25T23:58:13Z (27 years ago)
From
Roy Gal at CalTech <rrg@astro.caltech.edu>
GRB 980519 Optical Observations
R. R. Gal, J. S. Bloom, S. G. Djorgovski, and S. R. Kulkarni on behalf
of the Caltech GRB Collaboration, report:
"In addition to the I and R photometry reported by Bloom et al. (GCN
#87), we have photometered the B and V Palomar 200inch images of the
field of GRB 980519. Derived magnitudes of the following 7 secondary
stars are in the Landolt BV system (see GCN #87 for details):
Star B err(B) V err(V)
A 19.51 0.13 18.31 0.12
B 21.74 0.34 20.05 0.09
C 19.27 0.11 18.35 0.08
E 22.88 0.11 21.07 0.24
F 22.61 0.17 20.83 0.13
G 21.51 0.19 19.74 0.10
H 21.94 0.29 20.26 0.13
The derived magnitudes of the OT are:
May 20.4485 UT, B = 22.53 +/- .14
May 20.466 UT, V = 21.74 +/- .16
May 21.448 UT, B > 22.9 (3-sigma upper limit)
May 21.476 UT, V > 22.0 (3-sigma upper limit)
The non-detection on May 21 is consistent with the power-law decline
slope of beta = -1.98 reported in Djorgovski et al. (GCN #79).
Moreover, broadband colors circa May 20.4 (BV reported herein; RI
reported in Bloom #87) suggest a spectral index of alpha = -1.26 +/-
0.3. This is also consistent with the simple blastwave model
(eg. Wijers, Rees and Meszaros MNRAS 288, L51.) prediction that alpha
= (2/3) beta. The V-band point is somewhat higher (~3 sigma) than the
extrapolated spectrum, suggesting the spectrum of the transient may
not have been a pure power-law. Lastly, given the general consistency
of spectral slope with flux time decay, we note the absence of strong
extinction in the OT (in contrast to GRB 980329).
This report may be cited."
GCN Circular 96
Subject
GRB980519 Secondary Standards
Date
1998-06-05T00:37:19Z (27 years ago)
From
Arne A Henden at USNO/USRA <aah@nofs.navy.mil>
The U. S. Naval Observatory GRB team (A. A. Henden, F. J. Vrba,
C. B. Luginbuhl, B. Canzian, S. E. Levine, H. H. Guetter, J. A. Munn)
report follow up optical photometry of the secondary standards
(see Jaunsen, et. al. GCN 78 and Bloom, et. al. GCN 87) in the field
of GRB980519. The observations were made on two photometric nights
during the past week with the USNO 1.0m telescope. Johnson BV and
Cousins RI filters were used, with an average of 32 Landolt standards
of wide color range and extinction observed on each night. The
transformations are accurate to 0.01-0.02mag per single observation.
DAOPHOT psf fitting was used in the GRB field, with magnitude
corrections to adjust the photometry to a standard aperture diameter.
Given below is the photometry, with errors based on the variance
between the two nights. More detail, including coordinates and
comparisons between other published values for these stars, can
be found on our Web site at:
http://psyche.usno.navy.mil/nofs/grb/grb980519.html
For further information contact A. A. Henden at aah@nofs.navy.mil or by
telephone at (520) 779-5132.
This GCN note can be cited.
ID B Berr V Verr R Rerr I Ierr
--------------------------------------------------------------
A 19.661 0.114 18.558 0.018 17.914 0.005 17.338 0.027
B 20.218 0.061 19.318 0.027 18.477 0.001
C 19.313 0.060 18.549 0.027 18.029 0.004 17.525 0.004
D 16.433 0.003 15.614 0.005 15.139 0.000 14.686 0.004
E 21.230 0.146 19.998 0.030 18.767 0.022
F 21.174 0.226 19.900 0.109 18.578 0.289
G 19.915 0.006 18.867 0.004 17.999 0.054
H 20.574 0.062 19.432 0.044 17.990 0.050
I 20.054 0.021 19.645 0.042 19.138 0.007
J 20.907 0.036 20.001 0.011 19.148 0.011
GCN Circular 124
Subject
GRB980519 observation report
Date
1998-07-06T11:22:28Z (27 years ago)
From
Elia Leibowitz at Wise Obs, Tel Aviv U <elia@wise.tau.ac.il>
Elia Leibowitz and Peter Ibbetson, Wise Observatory, Tel Aviv University,
Israel report:
Using the Wise Observatory 1-m telescope and the observatory Tectronix CCD
camera, we obtained on May 20 a 1800 sec exposure of GRB980519, through a B
filter. The time of mid-exposure is 01:22:11 UT. The image of the optical
counterpart is at the limit of detectability. Applying the DAOPHOT
photometry package we measured the instrumental magnitude of the counterpart
and of nearby stars. Based on the B calibration of stars C and D of Henden
et al. (GCN Circ. #96), we estimate the B magnitude of the optical counterpart
as 20.95 +/- 0.25 mag.
This message is quotable in publications.
GCN Circular 148
Subject
GRB980519, Optical Observations
Date
1998-07-29T16:15:36Z (27 years ago)
From
Vladimir Sokolov at SAO RAS <sokolov@sao.ru>
The faintest GRB host galaxy?
V. Sokolov, S. Zharikov (SAO-RAS), E. Palazzi (ITeSRE-CNR),
L. Nicastro (IFCAI-CNR) and the SAX-GRB team report:
"On 1998 July 23.85 UT and 24.96 UT we obtained a deep Rc band image of
the field of the GRB 980519 optical transient (Jaunsen et al. GCN #78)
with the 6-m BTA telescope of SAO-RAS. The total observing time was 9600 s
with 600 s per exposure. Conditions were photometric with an average seeing
of 1.20 arcsec. A faint extended source is clearly detected at the position
of the OT. Due to the faintness of the object, we are not able to check
if between the two nights there was any luminosity variation.
The object magnitude was the same within the errors,
and the photometry of the GRB 980519 OT in 2.5 arcsec diameter aperture
was made by two observational nights and gave Rc = 26.05 +/- 0.22.
For photometric calibration we used the secondary standards from
Henden et al. (GCN #96).
From the time of optical observations of GRB980519 OT with Keck and Palomar
(GCN #88) in the R band
the assumed power-law decline slope of -1.98 (GCN #79) would make the OT
undetectable at the epoch of our observations.
So, we conclude that the OT has stopped its power law decay a long time ago,
and the observable now extended object is the host galaxy of GRB 980519 and
it could be the faintest among those known up today.
Images of the field will be posted at
http://www.sao.ru/~zhar/home/GRB/980519.html
This message can be cited."
GCN Circular 149
Subject
Optical Observations of the Host Galaxy of GRB 980519
Date
1998-08-03T17:26:21Z (27 years ago)
From
Josh Bloom at CIT <jsb@astro.caltech.edu>
J. S. Bloom, S. R. Kulkarni, S. G. Djorgovski, R. R. Gal, A. Eichelberger,
D. A. Frail report on behalf of the Caltech/NRAO GRB collaboration:
"Data were obtained on the Keck II telescope on July 18, 1998 UT by
Kulkarni and P. Groot (U. of Amsterdam) using the LRIS instrument. We
confirm the existence of a faint object with R_c= 26.1 +/- 0.3 (July
18.516) at the position of the optical transient of GRB 980519 (GCN #78)
and noted recently by Sokolov et al. (GCN 148). The exposure time was 1500
s. Despite excellent seeing conditions (0.6 arcsec, full width at half
maximum) we see little evidence for extension of the source, the presumed
host of the GRB. In addition, we note the non-detection (Gunn-i > 24.5)
of the host on July 29.396 1998 (2400 sec exp; 1.5 arcsec seeing) with
COSMIC on the 200-inch Telescope at Palomar.
The Keck image of the host of GRB 980519 and secondary standard stars (GCN
#87) may be obtained at http://astro.caltech.edu/~jsb/host_grb980519.ps"
This message may be cited.
GCN Circular 698
Subject
GRB980519, HST/STIS observations of the host galaxy
Date
2000-06-13T14:23:51Z (25 years ago)
From
Stephen Holland at IFA, U of Aarhus <holland@ifa.au.dk>
Stephen Holland, Johan Fynbo, Bjarne Thomsen (University of Aarhus),
Michael Andersen (University of Oulu),
Gunnlaugur Bjornsson (University of Iceland),
Jens Hjorth (University of Copenhagen),
Andreas Jaunsen (University of Oslo),
Priya Natarajan (Univeristy of Cambridge, & Yale), and
Nial Tanvir (University of Hertfordshire)
We have initiated a survey of the host galaxies of gamma-ray
bursts (GRBs) using the Space Telescope Imaging Spectrograph on the
Hubble Space Telescope. The data will consist of deep images of the
host galaxies of eleven GRBs taken at least one year after the GRB
occurred. We have waived the normal one-year proprietary period for
this data, and we will make drizzled images available to the
astronomical community. The web site for the Survey of the Host
Galaxies of Gamma-Ray Bursts is
"http://www.ifa.au.dk/~hst/grb_hosts/index.html".
We have obtained 8983 seconds of STIS images taken with the
50CCD (clear) aperture of GRB 980519. A combined image is now
available at "http://www.ifa.au.dk/~hst/grb_hosts/data/index.html".
This data was taken approximately 750 days after the burst. We find
two small galaxies within approximately 1.5 arcseconds of the GRB.
The bright galaxy has an AB magnitude of 27.0 +/- 0.1 in the STIS
50CCD (clear) aperture while the fainter galaxy, which we presume to
be the host, has an AB magnitude of 28.0 +/- 0.3. The total flux from
both objects agrees with the Kron-Cousins R-band magnitudes measured
by Hjorth et al. (1999, A&AS, 138, 461), Sokolov et al. (1998, GCNC
148), and Bloom et al. (1998, GCNC 149) if the combined colour of the
two galaxies is V-R = 0.8 +/- 0.4. The GRB occurred approximately 0.7
arcseconds to the north of the centre of the faint galaxy. The bright
galaxy shows some signs of a barred spiral structure. The central
regions have a full-width at half-maximum (after correcting for the
point spread function) of ~0.06 arcseconds. The faint galaxy is
elongated with an ellipticity of ~0.3 and a major axis of ~1
arcsecond.