- GCN notice #2984
J. A. Kennea, D. N. Burrows, J. E. Hill, D. Morris, J. A. Nousek (PSU), G.
Tagliaferri, C. Pagani, S. Campana, A. Moretti, P. Romano, G. Chincarini
(OAB), J. Osborne, K. Page, M. Goad, A. Beardmore, A. Wells (U. Leicester),
N. Gehrels, N. White, L. Angelini, F. Marshall (NASA/GSFC), P. Giommi
(ASI), K. MacGowan, K. Mason (MSSL) report on behalf of the Swift XRT team:
The Swift XRT instrument reports a preliminary position for GRB
050126. The BAT detected this burst at 12:00:53 UT on January 26,
2005. The S/C slewed to the burst immediately. The XRT was in Manual
State taking calibration observations of Mkn 876 in PC mode at the time of
the slew. We settled on the BAT position at 12:03:04 and immediately began
taking data in PC mode until 12:07:42, when we entered the South Atlantic
Anomaly. During this four minute period the XRT detected a very bright and
rapidly fading X-ray source. The initial position, based on the raw image
data with no correction for stellar aberration, is:
RA(J2000) = 18:32:25.8
Dec(J2000) = +42:22:0.4.
The estimated uncertainty in this early position is 30 arcseconds. A more
accurate position will be sent out when we are able to process these data
through the pipeline software.
- GCN notice #2985
E. Berger (Carnegie Observatories) and S.R. Kulkarni (Caltech) report on
behalf of a larger collaboration:
"We imaged the entire 30-arcsec radius XRT error circle of GRB 050126 (GCN
2984) with KeckI/NIRC on January 26.687 UT (4.5 hours after the burst) for
a total of 5 minutes in Ks band. A comparison to DSS and 2MASS reveals a
single bright source which is not visible in either catalog. The position
of the NIR afterglow is (J2000):
RA = 18:32:24.79
DEC= 42:21:54.0
This message may be cited.
- GCN notice #2986
V. Lipunov, A.Krylov, V.Kornilov, G.Borisov, D.Kuvshinov,
A.Belinski, M.Kuznetsov, S.Potanin, G.Antipov,
E.Gorbovskoy, N.Tyurina
Sternberg Astronomical Institute, Moscow
2,8 hours after SWIFT alert (GCN 2984) MASTER robotic
telescope (http://observ.pereplet.ru) had imaging the
corresponding area of the sky under the bad weather conditions on the
evening sky. We have
about 15 unfiltered images of the error box (45s exposition, 6 square
degrees
field) started at 26 Jan 2005 14:49:18 UT (2,8 hours after GRB time).
The better limiting magnitude on the images was about 15.5 (close to
R-band).
There is no OT within the 1' SWIFT error circle on 3 sigma level.
On the some of the images (around 15h 18m UT) we see (in the 1' SWIFT
error circle) very close
to noise one object
with coordinates
18 32 28.5
+42 21 47
(error = +-4'')
The optical limit on summ - 16.5.
JPG-images are available at
http://observ.pereplet.ru/images/050126/
This message may be cited.
This work is supported by Moscow Union
"OPTICA" and RFFI 04-02-16411.
Mailto: lipunov@sai.msu.ru
- GCN notice #2987
G. Sato (ISAS), P. Boyd (GSFC-UMBC), S. Barthelmy,
L. Barbier (GSFC), J. Cummings (GSFC), E. Fenimore (LANL),
N. Gehrels (GSFC), D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), C. Milvia (ASDC), K. McLean (LANL),
J. Nousek (PSU), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC), M. Suzuki (Saitama), J. Tueller (GSFC)
on behalf of the Swift-BAT team:
At 12:00:53 UT, the Swift Burst Alert Telescope (BAT) triggered and
located on-board GRB050126. The spacecraft autonomously slewed to the
burst and was detected by Swift/XRT as well (Kinnea et al., GCN #2984).
The burst is a FRED-type single broad peak, with a rapid rise (~1 sec)
and total duration ~30 seconds (T50 = 14 sec, T90 = 26 sec). The
total fluence is 1.1e-6 erg/cm2 (15-350 keV), and the peak five second
flux is 0.4 ph/cm2/sec (15-350 keV). The spectrum is consistent with
a power law with photon index 1.3 +/- 0.1 in the 20-150 keV band.
The spacecraft slew occurred between times 12:01:41 and 12:02:32 UT,
with a subsequent settling period until 12:03:02 UT. From 12:02:32
onward, there is no detectable gamma ray emission with an approximate
2 sigma upper limit of 7e-9 erg/cm2/s (15-350 keV) based on the above
spectrum.
The BAT ground-derived position is RA,Dec = 278.111, 42.384 (J2000)
with an estimated uncertainty of 4 arcmin (radius, 3-sigma, including
a systematic uncertainty). This is within 62 arcsec of the XRT
position (GCN #2984), and within 22 arcsec of the BAT on-board derived
position.
- GCN notice #2988
V. Lipunov, A.Krylov, V.Kornilov, G.Borisov, D.Kuvshinov,
A.Belinski, M.Kuznetsov, S.Potanin, G.Antipov,
E.Gorbovskoy, N.Tyurina
Sternberg Astronomical Institute, Moscow
2.8 hours after SWIFT GRB050126 detection (GCN 2984) MASTER robotic
telescope (http://observ.pereplet.ru) had imaging the
corresponding area of the sky under the bad weather conditions on the
evening sky (see GCN Circ 2986).
We have about 50 unfiltered images of the error box (30s exposition,
6 square degrees field, 355 mm diameter ) started at 26 Jan 2005
14:49:18 UT (2.8 hours after GRB time).
There is no OT at the KECK OT (GCN Circ 2985)position on 3 sigma
level. There is no OT inside BAT 8' error box (GCN Circ 2987) on
3 sigma level.
In the Table 1 you can see some reduction of images.
Table 1
----------------------------------------------------------------------
Time (UT) OT Limit (close to R)
for KECK position Circ 2985 Note
----------------------------------------------------------------------
14:54:47 >15.0
14:55:37 >15.0
14:56:26 >15.3
15:28:56 >15.6
15 16 06 - 15 28 00 >16.5 Sum of the 8 images
15 14 07 - 15 53 45 ~17.0 Sum of the 42 images
-----------------------------------------------------------------------
JPG-images are available at
http://observ.pereplet.ru/images/050126/ .
The sum 15 16 06 - 15 28 65 (UT) are available at
http://observ.pereplet.ru/images/050126/sum_8.jpg .
This message may be cited.
This work is supported by Moscow Union "OPTICA" and RFFI 04-02-16411.
Mailto: lipunov@sai.msu.ru
- GCN notice #2993
D. A. Frail (NRAO) and A. M. Soderberg (Caltech) report on behalf of
the Caltech-NRAO-Carnegie GRB Collaboration:
"We have used the VLA to make observations of the XRT error circle
(GCN #2984) for the Swift burst GRB050126 (GCN #2987). The
observations were carried out on 2005 January 26.67 UT (4 hrs after
the burst) and January 28.59 UT. At a frequency of 8.46 GHz no
emission was detected above 135 microJy (4-5 sigma) within the
30-arcsec diameter error circle. At the position of the NIR afterglow
candidate found by Berger and Kulkarni (GCN #2985) there is no
emission in excess of 30-45 microJy.
No further observations are planned."
- GCN notice #2996
S. Campana, G. Chincarini, A. Moretti, C. Pagani, P. Romano, G.
Tagliaferri (OAB),
D. N. Burrows, J. E. Hill, J. A. Kennea, D. Morris, J. A. Nousek (PSU),
M. Capalbi, P. Giommi, M. Perri, (ASDC/ASI), G. Cusumano, V. Mangano
(IASF/Pa),
J. Osborne, K. Page, M. Goad, A. Beardmore, A. Wells (U. Leicester), N.
Gehrels,
N. White, L. Angelini, F. Marshall (NASA/GSFC), K. McGowan, K. Mason
(MSSL)
report on behalf of the Swift XRT team:
We have obtained a new XRT position, using the ground-based pipeline
processing software, including stellar aberration correction. The analysis
is based on 4 different orbits and the source is detected each time.
Although
in the last orbits we have only few counts the derived coordinates are very
consistent and differ by less than 5 arcseconds.
The new position for the X-ray afterglow is:
RA(J2000) = 18:32:27.0,
Dec(J2000) = +42 22 13.5
We estimate a remaining uncertainty of about 8 arcseconds, including a
systematic error of about 5 arcseconds due to residual alignment offsets
that have not been fully calibrated yet.
- GCN notice #2997
E. Berger (Carnegie Observatories) reports on behalf of a larger
collaboration:
"A further examination of our Keck/NIRC image obtained on January 26.687
UT (4.5 hours after the burst; GCN 2985) and a comparison to the revised
XRT position (GCN 2996) reveals a point source which is not present in DSS
or 2MASS. The object is located about 1.9 arcsec from the nominal XRT
position at (J2000):
RA = 18:32:27.17
DEC= 42:22:13.6
We note that the previous source identified in GCN 2985 as the possible
afterglow of GRB 050126 falls outside of the revised XRT position. At the
present we do not have additional observations to test whether either
object has faded."
This message may be cited.
- GCN notice #3068
E. Berger (Carnegie Observatories), S.B. Cenko, D. Leonard (Caltech) and
B.E. Penprase (Pomona College) report on behalf of a larger collaboration:
"We observed the position of the near-IR afterglow candidate of GRB 050126
(Berger et al. astro-ph/0502468) with WIRC on the Palomar 200-inch
telescope on 2005, Feb 28.5 UT. A total of 30 minutes were obtained in
the Ks band. We find that the object has faded by at least 1.1 mag
confirming that it is in fact the afterglow. In addition, a faint source
is detected at the same position which is presumably the host galaxy."
- GCN notice #3088
E. Berger (Carnegie Observatories), S.B. Cenko and S.R. Kulkarni (Caltech)
report on behalf of a larger collaboration:
"We obtained spectra of the host galaxy of GRB 050126 with the Echelle
Spectrograph and Imager (ESI) mounted on the Keck II telescope.
Inspection of the 2-d and extracted spectra reveals a single emission line
at an observed wavelength of 8536.5 angstrom with continuum emission both
redward and blueward of the line. Interpreted as [OII]3727 this indicates
a redshift of z=1.29, the first for any Swift GRB. At this redshift,
given a fluence of 2e-6 erg/cm^2 (Berger et al. astro-ph/0502468), the
isotropic-equivalent gamma-ray energy is 8.7e51 erg."
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