GRB 050410

V. La Parola, V. Mangano, T. Mineo, G. Cusumano  (INAF-IASF/Palermo), J. A. 
Kennea, D. N. Burrows  (PSU), C. Pagani,  P. Romano (INAF-OAB), J. P. 
Osborne, P. T. O'Brien (U. Leicester),  M. Capalbi, F. Tamburelli (ASDC), 
B. Zhang (U. Nevada), R. Fink, S. Barthelmy and N. Gehrels (GSFC), report 
on behalf of the Swift XRT team:

The Swift BAT instrument found Triggers 114298/114299 (possibly GRB 050410) 
at 12:14:25 UT on 10 April 2005.  The target was within the Swift Earth 
constraint and the observatory executed a delayed automated slew to the BAT 
position at 12:44:20.  The XRT began taking data at 12:46:27 UT, about 32 
minutes after the burst.  The afterglow was too faint for the XRT to 
produce an on-board centroid.  Ground processing shows a faint uncataloged 
X-ray source located at:

RA(J2000) = 05:59:12.9
Dec(J2000) = +79:36:9.2

We estimate an uncertainty of about 5 arcseconds radius (90% 
containment).   This source is located 38 arcseconds from the BAT position 
for Trigger 114299.

E. Fenimore (LANL), L. Barbier, S. Barthelmy (GSFC), J. Cummings (GSFC/NRC),
M. Galassi (LANL), N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/NRC), G. Sato (ISAS), M. Suzuki (Saitama),
M. Tripicco (GSFC-SSAI), J. Tueller (GSFC)
on behalf of the Swift-BAT team:

At 12:14:25.36 UT Swift-BAT triggered on burst GRB 050410 (trigger=114298).
The BAT ground position is RA,Dec=89.745,+79.601 (J2000).  We note this
is 38 arcsec from the XRT position (Parola, et al, Circ 3218).  For this GRB
there were two BAT triggers (114298 and 114299; 9 sec apart).  This is a result
of a rare timing condition in the on-board software where the triggering code 
times-out while waiting for the imaging results of the first trigger,
then BAT goes back into the triggerable state, and then triggers again
(on the same burst) which then produces the second trigger number and
the second series of BAT-related GCN Notices.

The lightcurve shows a broad peak with a total burst duration of ~65 sec
(T90=43sec in 15-350 keV).  The rise of the burst was slow, causing a
delayed trigger, which continued to the back-to-back triggering situation.
The burst starts about 10 sec before the 114298 trigger time. 

A simple power law fit yields a photon index of -1.6 +/- 0.1, a burst fluence
of 6.9e-6 erg/cm2 , and the 1-sec peak flux of 2.0 ph/cm2/sec (15-350 keV).
There is emission across the full BAT range including the 100-350 keV band.
The burst was 43 deg off the BAT bore sight with a partial coding of 20%.

P. Boyd (GSFC), V. Mangano (INAF-IASF/Palermo), S. T. Holland (GSFC),  S. 
Hunsberger (PSU), T. Poole (MSSL), M. Still (GSFC), N. Gehrels (GSFC), K. 
Mason (MSSL), J. Nousek (PSU) report, on behalf of the Swift UVOT team:

The Swift Ultra-Violet/Optical Telescope (UVOT) began settled 
observations of the field of GRB 050410 (Parola et al; GCN 3218
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 ) at 
12:46:17 UT on 10 April 2005. This is immediately after the target exited 
the Swift Earth-limb constraint, 1912 seconds after the BAT trigger.  

The first UVOT data arrived via TDRSS; it is a 100s V image starting 
immediately after spacecraft settling, binned 8x8 (pixel size 4.x4. 
arcsec) centered on the BAT position, and 5.33 arcminutes per side. 
Mid-exposure time was 1962 s after the trigger. A comparison against the 
Digitized Sky Survey reveals no new sources within the BAT and XRT error 
circles down to a 5-sigma background limit of V = 18.5  with a systematic 
uncertainty of 0.1 mag (due to uncertainties in the photometric zero 
point). This limit is based upon preliminary flight calibrations.

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

After  Swift alert 114299   MASTER robotic telescope
(http://observ.pereplet.ru)
had  imaging  the corresponding area of the sky  under the bad weather
conditions at 17:14:08.03 UT (5h after GRB Time, OUR SUNSET ).
There are no new object up to 14.7 on unfiltered image of the error box
(30s exposition, 6 square  degrees field).
The limit on summ (between 18h17m - 18h30m UT) is about 18.5 .
We have about 50 images.

The JPG-images of summ  are available at
http://observ.pereplet.ru/images/GRB050410/summ1.jpg
This message may be cited.

This work is supported by Moscow Union "Optic" and partly supported by
RFFI 04-02-16411.
Mailto: lipunov@sai.msu.ru

A. M. Soderberg (Caltech) reports on behalf of the
Caltech-NRAO-Carnegie GRB collaboration:

"Using the Very Large Array at 8.5 GHz, we observed the
field of GRB050410 (GCN 3219
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 ) on 2005 Apr 10.72 UT.
We do not detect a radio source coincident with the
Swift XRT position (GCN 3218
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 ).  We place a 2-sigma upper
limit of 114 uJy on the XRT error region.

Further observations are planned."

B. Stecklum, S. Klose, U. Laux, Thuringer Landessternwarte Tautenburg,
J. Greiner, MPE Garching,

report:

Tautenburg started observing the error box of GRB 050410 on Apr 10,
20:10 UT. A first inspection of the first R-band images does not show a
source in the Swift/XRT error circle (La Parola et al. 2005,
GCN 3218
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 ) down to the DSS2 red limit.

E. O. Ofek, Y. Lipkin (Wise observatory, TAU) report:

We have observed the error box of GRB 050410 (La Parola et al. 2005,
GCN 3218
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 ) using the Wise observatory 1m telescope + Tek CCD camera,
starting at 2005, Apr 10th, 17:05 UT.
Seven 300 sec R-band images were combined (mid exposure time 5.25 hours
after the burst).

No new source was detected within a radius which is twice the Swift XRT
error circle radius, down to a limiting magnitude of R=20.0

Kuntal Misra (ARIES, Naini Tal), A. de Ugarte Postigo, M. Jelinek
(IAA-CSIC Granada Spain), Atish P. Kamble (Raman Research Institute, Bangalore)
S. B. Pandey (ARIES, Naini Tal), A.J. Castro-Tirado (IAA-CSIC Granada Spain)
on behalf of larger GRB collaboration

We monitored the SWIFT (trigger = 114299) localization of GRB 050410
using the 1.04-m reflector at ARIES, Naini Tal. The observations
started around 15:56 UT (3h 42m after the burst). We do not detect
any new fading source down to DSS limit (R_c ~ 20.5 mag) in
6*300sec + 4*900sec exp time.

This message can be cited.

V.Rumyantsev (CrAO), V.Biryukov (SAI, MSU), and A.Pozanenko (IKI) on behalf
of larger GRB follow up collaboration report:

We have obtained 20 unfiltered images of the Swift trigger #114298 error box
(GRB050410, Fenimore et al., GCN 3219
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 ).  The images were taken with the
AT-64 telescope of Crimean Astrophysical observatory and cover the period UT
17:25 - 18:20 of  April 10, 2005. No new source was found within SWIFT  the
XRT position (Parola, et al., GCN 3218
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 ) in comparison with DSS2 (R).
Limiting magnitude of the combined image (S/N=3) calibrated against R
USNO-A2.0 is following

Mid Time(UT)       telescope   exposure    limiting mag.
April 10  17:57        AT-64     20x120 s       20.4

This message can be cited.

P. Boyd (GSFC-UMBC), S. T. Holland, M. Still (GSFC-USRA), V. Mangano
(INAF-IASF/Palermo), S. Hunsberger, (PSU), T. Poole (MSSL), N. Gehrels
(GSFC), K. Mason (MSSL), J. Nousek (PSU), and A. Wells (Leicester) on
behalf of the Swift UVOT team report:

     The Swift Ultraviolet/Optical Telescope (UVOT) observed the field
of GRB 050410 (Fenimore et al., GCN 3219
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 ) starting at 12:46:04 UT on
10 April 2005.  We find no evidence for a source in the 5 arcsecond
radius XRT error circle (La Parola et al., GCN 3218
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 ) in the UVOT data.
The 3-sigma limiting magnitudes in a 3.5 arcsecond radius circular
aperture , and the coadded exposure times, are: V = 19.9 (392 s), B =
21.2 (1199 s), U = 20.9 (1326 s), UVW1 = 20.8 (399 s), UVM2 = 21.1
(399 s), and UVW2 = 21.7 (788 s).  The magnitudes reported in this
Circular are based upon preliminary flight calibrations.

S. Bradley Cenko and Derek B. Fox report on behalf of the Caltech-NRAO-
Carnegie GRB Collaboration:

We have imaged the field of GRB050410 with the automated Palomar 60-inch
telescope.  Observations consisted of 10 x 120 second images each in the
Gunn i and z bands.  At a mean epoch of approximately 3:50 UT (15.6
hours after the burst), we find no evidence for any source in the XRT
error circle (GCN 3218
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 ).  Our limiting magnitudes, from comparison with
several stars in the USNO-B1 catalog, are approximately i < 21.5, z <
20.0.