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SGR 1900+14  



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TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  94
SUBJECT: SGR1900+14
DATE:    98/06/03 01:03:48 GMT
FROM:    Kevin Hurley at UCBerkeley/SSL  <khurley@sunspot.ssl.berkeley.edu>

K. Hurley, Space Sciences Laboratory, on behalf of the Ulysses
Gamma-Ray Burst Team; C. Kouveliotou, Universities Space Research
Association, on behalf of the Gamma-Ray Observatory BATSE team; and E.
Mazets and  T. Cline, on behalf of the KONUS-WIND team, report: "This
soft gamma repeater has entered an extraordinary new phase of activity
with a previously unobserved frequency and intensity of bursts.
Activity began  on May 26 and has continued at least through May 30.
Triangulation with Ulysses and BATSE gives a preliminary annulus whose
center is at (equinox 2000.0) R.A. = 21h58m18s, Decl. = -11o18'.4, and
whose radius is 47.269 +/- 0.019 deg.  This annulus includes the
network synthesis error box (Hurley et al. ApJ 431, L31, 1994), the
ROSAT source proposed as a possible quiescent X-ray counterpart to the
soft repeater (Hurley et al. ApJ 463, L13, 1996), and the peculiar
double M star system coincident with the ROSAT source (Vrba et al. ApJ
468, 225, 1996).  As all these locations are mutually consistent, we
conclude that the ROSAT source and M star system are indeed the
counterparts to the soft gamma repeater, and urge that observations at
other wavelengths be undertaken immediately, while the source remains
active.  An image may be found at http://ssl.berkeley.edu/ipn3/sgr1900+14/"

C. Kouveliotou, Universities Space Research Association, P. Woods, M.
Kippen, M.S. Briggs, University of Alabama in Huntsville, K. Hurley,
Space Sciences Laboratory, report: "On May 30th, BATSE triggered on an
extremely intense outburst from this source that comprised at least 38
bursts of varying intensity and duration; the series of bursts started
at 32624 s UT, and lasted for about 350s. The peak flux of each of the
three major bursts in the series is 1.1x10e-4 ergs/cm^2 s (between
25-300 keV, integrated for 128 ms). Assuming a distance of about 12
kpc for SGR 1900+14 (F. Vrba et al., ApJ 468, 225 1996), this
corresponds to a luminosity of about 2x10e42 ergs/s for each burst.
This bunching of emission is very similar to the behaviour of SGR
1806-20, as detected with the Rossi X-Ray Timing Explorer in 1996 (C.
Kouveliotou, et al, IAUC 6503). Overall, between May 26 and June 1st,
we have detected over 50 bursts from SGR 1900+14. The frequency and
intensity of emissions are unlike any previously seen behaviour from
this source. We strongly encourage follow up observations in infra-red
and radio wavelengths, while the source is still active."

These messages are citeable.



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[Operators Note: This is the 2nd distribution -- see explanation below.]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  95
SUBJECT: SGR1900+14
DATE:    98/06/03 01:40:08 GMT
FROM:    Kevin Hurley at UCBerkeley/SSL  <khurley@sunspot.ssl.berkeley.edu>

K. Hurley, Space Sciences Laboratory, on behalf of the Ulysses
Gamma-Ray Burst Team; C. Kouveliotou, Universities Space Research
Association, on behalf of the Gamma-Ray Observatory BATSE team; and E.
Mazets and  T. Cline, on behalf of the KONUS-WIND team, report: "This
soft gamma repeater has entered an extraordinary new phase of activity
with a previously unobserved frequency and intensity of bursts.
Activity began  on May 26 and has continued at least through May 30.
Triangulation with Ulysses and BATSE gives a preliminary annulus whose
center is at (equinox 2000.0) R.A. = 21h58m18s, Decl. = -11o18'.4, and
whose radius is 47.269 +/- 0.019 deg.  This annulus includes the
network synthesis error box (Hurley et al. ApJ 431, L31, 1994), the
ROSAT source proposed as a possible quiescent X-ray counterpart to the
soft repeater (Hurley et al. ApJ 463, L13, 1996), and the peculiar
double M star system coincident with the ROSAT source (Vrba et al. ApJ
468, 225, 1996).  As all these locations are mutually consistent, we
conclude that the ROSAT source and M star system are indeed the
counterparts to the soft gamma repeater, and urge that observations at
other wavelengths be undertaken immediately, while the source remains
active.  An image may be found at http://ssl.berkeley.edu/ipn3/sgr1900+14/"

C. Kouveliotou, Universities Space Research Association, P. Woods, M.
Kippen, M.S. Briggs, University of Alabama in Huntsville, K. Hurley,
Space Sciences Laboratory, report: "On May 30th, BATSE triggered on an
extremely intense outburst from this source that comprised at least 38
bursts of varying intensity and duration; the series of bursts started
at 32624 s UT, and lasted for about 350s. The peak flux of each of the
three major bursts in the series is 1.1x10e-4 ergs/cm^2 s (between
25-300 keV, integrated for 128 ms). Assuming a distance of about 12
kpc for SGR 1900+14 (F. Vrba et al., ApJ 468, 225 1996), this
corresponds to a luminosity of about 2x10e42 ergs/s for each burst.
This bunching of emission is very similar to the behaviour of SGR
1806-20, as detected with the Rossi X-Ray Timing Explorer in 1996 (C.
Kouveliotou, et al, IAUC 6503). Overall, between May 26 and June 1st,
we have detected over 50 bursts from SGR 1900+14. The frequency and
intensity of emissions are unlike any previously seen behaviour from
this source. We strongly encourage follow up observations in infra-red
and radio wavelengths, while the source is still active."

These messages are citeable.



[GCN Operator's Note:  The process table on the machine used by the
GCN Circular system exceeded the maximum number of processes.  This
caused about 15 e-mails to be aborted.  This re-invoking the mailing
will fix the omission (with about a 30 minute extra delay).  Since it is
impossible to determine to the exact person in the list when the overflow
started and when it stopped, a few of you will be receiving a second
copy of this circular so as to make sure that everyone receives at least
one copy -- my apologies for the duplication.  Also, the re-invokation
results in a Circular number (=95) different from the number for the 
original mailing (=94).  Pepole should use the original number (94)
when making citations.  The GCN Circular distribution program has been fixed
to prevent this problem from recurring.]



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                                                 Circular No. 6929
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)

SGR 1900+14
     K. Hurley, Space Sciences Laboratory, on behalf of the Ulysses
Gamma-Ray Burst Team; C. Kouveliotou, Universities Space Research
Association, on behalf of the Gamma-Ray Observatory BATSE team; and
E. Mazets and T. Cline, on behalf of the KONUS-WIND team, report:
"This soft gamma-ray repeater has entered an extraordinary new
phase of activity with a previously unobserved frequency and
intensity of bursts.  Activity began on May 26 and has continued at
least through May 30.  Triangulation with Ulysses and BATSE gives a
preliminary annulus whose center is at R.A. = 21h58m18s, Decl. =
-11o18'.4 (equinox 2000.0), and whose radius is 47.269 +/- 0.019
deg.  This annulus includes the network synthesis error box (Hurley
et al. 1994, Ap.J. 431, L31), the ROSAT source proposed as a
possible quiescent x-ray counterpart to the soft repeater (Hurley
et al. 1996, Ap.J. 463, L13), and the peculiar double M star system
coincident with the ROSAT source (Vrba et al. 1996, Ap.J. 468, 225).
As all these locations are mutually consistent, we conclude that
the ROSAT source and M star system are indeed the counterparts to
the soft gamma-ray repeater, and urge that observations at other
wavelengths be undertaken immediately, while the source remains
active.  An image may be found at
http://ssl.berkeley.edu/ipn3/sgr1900+14/."
     C. Kouveliotou, Universities Space Research Association; P.
Woods, M. Kippen, and M. S. Briggs, University of Alabama in
Huntsville; and K. Hurley, Space Sciences Laboratory, write:  "On
May 30, BATSE triggered on an extremely intense outburst from this
source that comprised at least 38 bursts of varying intensity and
duration; the series of bursts started at May 30.37759 UT and
lasted for about 350 s.  The peak flux of each of the three major
bursts in the series is 1.1 x 10E-4 erg cmE-2 sE-1 (between 25 and
300 keV, integrated for 128 ms).  Assuming a distance of about 12
kpc for SGR 1900+14 (Vrba et al. 1996, Ap.J. 468, 225), this
corresponds to a luminosity of about 2 x 10E42 ergs/s for each
burst.  This bunching of emission is very similar to the behavior
of SGR 1806-20, as detected with the Rossi X-Ray Timing Explorer in
1996 (IAUC 6503).  Overall, between May 26 and June 1, we have
detected over 50 bursts from SGR 1900+14.  The frequency and
intensity of emissions are unlike any previously seen behavior from
this source.  We strongly encourage follow-up observations at
infrared and radio wavelengths, while the source is still active."

                      (C) Copyright 1998 CBAT
1998 June 3                    (6929)            Daniel W. E. Green



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TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  97
SUBJECT: SGR 1900+14
DATE:    98/06/05 00:43:43 GMT
FROM:    Josh Bloom at CIT  <jsb@astro.caltech.edu>

SGR 1900+14 IR Observations

B. R. Oppenheimer, J. S. Bloom, S. S. Eikenberry, and K. Matthews
(Caltech) report: "We have obtained narrowband 2.2 micron images of
the proposed infrared counterpart to SGR 1900+14 (Vrba et al. 1996,
Ap.J. 468, 225) at June 3.486 UT, 4.1 days after the recent bursting
activity reported by Hurley et al. and Kouveliotou et al. (IAUC 6929).
Differential photometry of stars "A" and "B" (the double M -stars) and
star "C" of Vrba et al. show A-B=0.4 +-0.1 mag and A-C=4.5+-0.2 mag,
consistent with the measurements of Vrba et al.  Over the course of 10
minutes (ten separate frames) no variability was detected in the
double M-stars to a limit of 0.1 mag."

This report may be cited.


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                                                 Circular No. 6933
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)

SGR 1900+14
     B. R. Oppenheimer, J. S. Bloom, S. S. Eikenberry, and K.
Matthews, California Institute of Technology, communicate: "We have
obtained narrowband 2.2-micron images of the proposed infrared
counterpart to SGR 1900+14 (Vrba et al. 1996, Ap.J. 468, 225) on
June 3.486 UT, 4.1 days after the recent bursting activity reported
on IAUC 6929.  Differential photometry of stars 'A' and 'B' (the
double M stars) and star 'C' of Vrba et al. yields m_A-m_B = +0.4
+/- 0.1 and m_A-m_C = +4.5 +/- 0.2 mag, consistent with the
measurements of Vrba et al.  Over the course of 10 min (ten
separate frames), no variability was detected in the double M stars
to a limit of 0.1 mag."

                      (C) Copyright 1998 CBAT
1998 June 5                    (6933)            Daniel W. E. Green


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TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  120
SUBJECT: SGR1900+14 field optical observations
DATE:    98/06/30 17:05:16 GMT
FROM:    Arne A Henden at USNO/USRA  <aah@nofs.navy.mil>

A. Henden, C. Luginbuhl and F. Vrba (U.S. Naval Observatory Flagstaff
Station) report that they have obtained extensive I-band and J-band
observations of the near-IR sources and surrounding field associated
with SGR1900+14 both before and after the recent onset of activity.
None of the observations coincide with bursts detected by BATSE, and no
unusual photometric behavior has been detected though reductions are
ongoing.  A new eclipsing binary has been detected nearby, however, at
RA 19:07:16.85 DEC +09:18:50.4 (J2000), about 39.0 arcseconds SE of
the M supergiant pair.  The binary is about I=19.1 out of eclipse,
and has been observed through several eclipses of about 0.4mag depth.
The period is either about 1.07day or some integer fraction.
This binary appears as the star labelled 'J' in Figure 1 of
Vrba et. al. ApJ 468:225 (1996).  We bring this star to the attention of
other observers in the hope that it not send anyone on a wild goose
chase if it is detected as a variable in observations of this
gamma-ray burst location.

This message is quotable in publications.


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TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  121
SUBJECT: Radio observations of SGRs
DATE:    98/07/01 17:10:46 GMT
FROM:    Dale A Frail at NRAO  <dfrail@nrao.edu>


D. A. Frail, National Radio Astronomy Observatory and S. R. Kulkarni,
California Institute of Technology report: 

The recent renewed activity from SGR1900+14 (GCN #94) and the
newly-discovered SGR1627-41 (GCN #107) prompted VLA radio observations
at 8.46 GHz on 1998 June 25. For SGR1900+14 we observed a field
centered on the proposed X-ray/infrared counterpart (Hurley et
al. ApJ, 463, L13, 1996, Vrba et al. ApJ, 468, 225, 1996). For
SGR1627-41 we observed the 95 arcsec diameter supernova remnant CTB33
(IAU Circ. 6948), most recently studied by Sarma, Goss, Green & Frail
(ApJ, 483, 335, 1997).  The synthesized beam was approximately 1
arcsec. The interferometer is insensitive to extended structure on
angular scales larger than 20 arcsec.

No point sources were visible above 200 microJy and 345 microJy
(4-sigma) for the SGR1900+14 and SGR1627-41, respectively.

This report can be cited.


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TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  153
SUBJECT: SGR1900+14, BeppoSAX-GRBM observations
DATE:    98/09/01 15:49:39 GMT
FROM:    Marco Feroci at IAS/CNR Frascati  <feroci@ias.rm.cnr.it>

SGR 1900+14
        M. Feroci, P. Soffitta, E. Costa, Istituto di Astrofisica
Spaziale, CNR, Rome, and F. Frontera, Istituto Tecnologie e Studio
Radiazioni Extraterrestri, CNR, Bologna, on behalf of the
BeppoSAX/GRBM team, and M. Tavani, Istituto di Fisica
Cosmica, CNR, Milano, and Columbia Astrophysics Laboratory, New York,
report:

"The Gamma-Ray Burst Monitor (GRBM) onboard BeppoSAX was triggered by
the event reported by Cline et al. (IAUC 7002) on Aug. 27.4321259.
The event showed a fast rise (<1s) and an exponential-like decay,
lasting more than 300s. The event was observed at an off-set angle of
about 56 degrees from the axis of GRBM unit 1, and showed a peak intensity
in (40-700 keV) of about 64000 c/s.  The event was clearly detected
above 100 keV.  A preliminary analysis shows that the spectrum is
hard during the initial 1s, followed by a sudden softening.  Subsequent
spectral evolution shows a progressive hardening.
The near-5s periodicity reported by Cline et al. (IAUC 7002) is evident
in the GRBM data for the entire duration of the event.
In addition, starting from about 35s after the event onset, the GRBM
clearly detected a periodic pattern of subpulses for each near-5s
oscillation.  The repetitive pattern is made of four subpulses of period
near-1s.
More detailed temporal and spectral analyses are in progress."