GRB 141104A

K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team,

S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks,
D. Svinkin, and T. Cline on behalf of the Konus-Wind team,

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer,
on behalf of the Swift-BAT team,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C.
Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, and

W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on
behalf of the GRS-Odyssey GRB team, report:

The long-duration, very bright GRB 141104A has been observed by Swift 
(BAT), Konus-Wind, Mars Odyssey (HEND), MESSENGER (GRNS), and  INTEGRAL 
(SPI-ACS), so far, at about 200 s UT (00:03:20). The burst was outside 
the coded field of view of the BAT.

We have triangulated it to a preliminary, 3 sigma error box whose 
coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   279.488 (18h 37m 57s) -12.702 (-12d 42' 07")
  Corners:
   279.368 (18h 37m 28s) -12.296 (-12d 17' 45")
   279.549 (18h 38m 12s) -12.326 (-12d 19' 32")
   279.607 (18h 38m 26s) -13.111 (-13d 06' 38")
   279.426 (18h 37m 42s) -13.078 (-13d 04' 41")
  ---------------------------------------------
The error box area is 492 sq. arcmin, and its maximum
dimension is 51 arcmin (the minimum one is 10 arcmin).
The Sun distance was 58.5 deg.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB141104_T00199/IPN/

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.

S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lyssenko, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration, very bright GRB 141104A
(IPN triangulation: Hurley et al., GCN 17026
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 )
triggered Konus-Wind at T0=199.517 s UT (00:03:19.517).

The light curve shows a double-peaked structure with
a total duration of ~25 s.
The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst had a fluence
of 5.9(-0.4,+0.4)x10^-5 erg/cm2, and a 64-ms peak flux,
measured from T0+8.064 s, of 1.6(-0.1,+0.1)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum (measured from T0 to T0+27.136 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.09 (-0.11,+0.13),
the high energy photon index beta = -2.57 (-0.25,+0.15),
the peak energy Ep = 160 (-13,+16) keV,
chi2 = 96/96 dof.

The spectrum near the peak count rate (measured from T0+7.424 to T0+8.960 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.86 (-0.09,+0.11),
the high energy photon index beta = -3.32 (-0.81,+0.42),
the peak energy Ep = 232 (-18,+16) keV,
chi2 = 98/96 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB141104_T00199/

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.

P. A. Evans (U. Leicester) reports on behalf of the Swift team:

Swift has initiated a series of observations, tiled on the sky, of the
IPN GRB 141104A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00032

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the IPN event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; and 2009, MNRAS, 397, 1177).

This circular is an official product of the Swift-XRT team.

V. D'Elia (ASDC) & L. Izzo (URoma/ICRA) report on behalf of the Swift-XRT team

Swift-XRT has observed the error box of the IPN GRB 141104A (Hurley et  
al. GCN 17026
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 ) in a series of observations tiled on the sky. The total  
exposure time is 14.0 ks spread over 3 fields. The observations  
started ~ 3 days after the IPN trigger. We detect four sources with  
S/N ~ 3 or higher, within or close to the IPN error box. Namely  
(ordered by ascending Dec):

Source 1
RA: 279.53959 = 18h 38m 9.50s (J2000)
Dec: -13.06216 = -13d 03' 43.8" J(2000)
Err: 4.4 arcsec (radius, 90% confidence).
Exposure time: 3.9 ks.

Source 2
RA:  279.51690	= 18h 38m 4.06s (J2000)
Dec:  -12.78750  = -12d 47' 15.0" (J2000)
Err: 4.9 arcsec (radius, 90% confidence)
Exposure time: 4.4 ks

Source 3
RA: 279.38702  = 18h 37m 32.88s (J2000)
Dec: -12.34930 = -12d 20' 57.5" (J2000)
Err: 3.8 arcsec (radius, 90% confidence).
Exposure time: 3.4 ks.

Source 4
RA: 279.49073 = 18h 37m 57.78s (J2000)
Dec: -12.30119 = -12d 18' 04.3" (J2000)
Err: 4.6 arcsec (radius, 90% confidence).
Exposure time: 3.1 ks.


The northernmost Sources #3 and #4 are close to (#3) or just outside  
(#4) the IPN error box and possess an X-ray and optical counterpart,  
so are likely unrelated to the afterglow. The central source #2 has an  
optical counterpart, while the southernmost source #1 does not have  
counterparts. The most promising XRT afterglow candidate is thus  
source #1, although the counterpart of #2 could be the host galaxy of  
the afterglow.  We cannot measure variability at this time, so a  
secure identification of the afterglow is not possible.

Details on the present analysis can be found at:

http://www.swift.ac.uk/xrt_products/TILED_GRB00032/


This is an official product of the Swift-XRT team.

V. D'Elia (ASDC), L. Izzo (URoma/ICRA) and D. Malesani (DARK/NBI)  
report on behalf of the Swift-XRT team

Swift-XRT has observed again a field in the error box of the IPN GRB  
141104A (Hurley et al. GCN 17026
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 ). The total exposure time of the new  
observation, which started ~ 10 days after the IPN trigger, is 9 ks.  
Source #2 reported in D'Elia & Izzo (GCN 17036
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 ) is still detected with  
a consistent count rate, while source #1 is marginally detected at a  
S/N level just below 3. The count rate of the new detection clearly  
implies fading between the two epochs. Despite the slow temporal decay  
(t^-0.55) and the flux variation of a factor of just two that can not  
exclude another origin, source #1 is the best afterglow candidate for  
GRB 141104A. Further observations are Sun constrained until February  
2015.

Details on the present analysis can be found at:

http://www.swift.ac.uk/xrt_products/TILED_GRB00032/


This is an official product of the Swift-XRT team.