GRB 120403A

A. P. Beardmore (U Leicester), S. D. Barthelmy (GSFC),
D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC), V. D'Elia (ASDC),
C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), T. Sakamoto (NASA/UMBC),
B. Sbarufatti (INAF-OAB/PSU) and C. A. Swenson (PSU) report on behalf
of the Swift Team:

At 01:05:23 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 120403A (trigger=519211).  Swift did not slew because
of the Sun observering constraint.  The BAT on-board calculated location is 
RA, Dec 42.459, +40.466 which is 
   RA(J2000)  =  02h 49m 50s
   Dec(J2000) = +40d 27' 57"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single spike
with a duration of about 2 sec.  The peak count rate
was ~2200 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 18:44 UT on 2012 June 25. There will thus be no XRT or
UVOT data for this trigger before this time. 

Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
A. P. Beardmore (U Leicester), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 120403A (trigger #519211)
(Beardmore, et al., GCN Circ. 13191
Loading...
 
 ).  The BAT ground-calculated position is
RA, Dec = 42.458, 40.489 deg which is 
   RA(J2000)  =  02h 49m 49.8s 
   Dec(J2000) = +40d 29' 21.8" 
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 50%.
 
The mask-weighted light curve shows a single peak, starting at T+0 s, 
peaking at T+0.1 s and ending at T+1.8 s.  T90 (15-350 keV) is 1.25 +- 0.19 sec 
(estimated error including systematics).
 
The time-averaged spectrum from T+0.0 to T+1.4 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.64 +- 0.30.  The fluence in the 15-150 keV band is 1.0 +- 0.2 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.04 sec in the 15-150 keV band
is 1.1 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/519211/BA/

V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk


E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina,
N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov,  V.V.Chazov, A.Kuznetsov,
A.Sankovich
Moscow Lomonosov State University, Sternberg Astronomical Institute,

K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk
Irkutsk State University

A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik
Kislovodsk Solar Station of the Pulkovo Observatory

V.Krushinski, I.Zalozhnich,  A. Popov, A. Bourdanov, A. Punanova
Ural Federal University

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)


MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Blagoveschensk was pointed to the  GRB120403A 35321 sec s 
after notice time and 36026 sec after GRB time at 2012-04-03 11:05:49.415 
UT. On our first (180s exposure) set we haven`t found optical transient 
within SWIFT error-box (Beardmore et al., GCN Circ 13191
Loading...
 
 ).
The 5-sigma upper limit has been about 16.0 mag
The message may be cited.

The long delay  was due to the  Eath rotation.

The message may be cited.

J. Norris (BSU), T. Sakamoto (GSFC/UMBC), S.D. Barthelmy (GSFC), 
J. R. Cummings (GSFC/UMBC) for the BAT Team:

We report the spectral lag analysis for GRB 120403A (Beardmore, et al., GCN Circ. 13191
Loading...
 
 )
based on the BAT data.  Using 64-ms binned light curves, the spectral lag
for the 15-25 keV to 50-100 keV bands is 63 +380/-180 msec.  Because of a relatively
large error in the lag measurement due to a weak nature of the burst, we can not
conclusively say that this burst is in the short burst category.