GRB 140104B

G. Vianello (Stanford University), J. McEnery (NASA/GSFC), and E.
Sonbas (Adiyaman Univ.), report on behalf of the Fermi-LAT team:

Starting at 17:32:03.15 on Jan. 4, 2014, Fermi LAT detected high
energy emission from GRB 140104B, which was also detected by Fermi-GBM
(trigger 410549526).

The best LAT on-ground location is found to be R.A., Dec 218.81, -8.90
deg (J2000) with an error radius of 0.22 deg (90% containment,
statistical error only), which was 25 deg from the LAT boresight at
the time of the trigger.

The data from the Fermi LAT show a significant increase in the event
rate within 10 deg of the GBM location after the GBM trigger that is
spatially and temporally correlated with the GBM emission with high
significance. The highest-energy photon is a 1.8 GeV event which is
observed ~800 seconds after the GBM trigger.

A Swift ToO has been requested for this burst.

The Fermi LAT point of contact for this burst is Eda Sonbas
(edasonbas@yahoo.com).

The Fermi LAT is a pair conversion telescope designed to cover the
energy band from 20 MeV to greater than 300 GeV. It is the product of
an international collaboration between NASA and DOE in the U.S. and
many scientific institutions across France, Italy, Japan and Sweden.

[GCP OPS NOTE(06jan14): Per author's request, name of the burst
in the subject line was corrected by removing the "731" ending.]

Shaolin Xiong (UAH) reports on behalf of the Fermi GBM Team:

"At 17:32:03.15 UT on 04 January 2014, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 140104B (trigger 410549526 / 140104731),
which was also detected by the ground analysis of Fermi/LAT
(Vianello et al. 2014, GCN 15684
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 )
The GBM on-ground location is consistent with the LAT position.

The GBM light curve consists of multiple pulses
with a duration (T90) of about 190 s (50-300 keV).
The time-averaged spectrum from T0 to T0+200 s is
well fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.23 +/- 0.06 and
the cutoff energy, parameterized as Epeak, is 280 +/- 40 keV.

The event fluence (10-1000 keV) in this time interval is
(3.2 +/- 0.2)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+190.7 s in the 10-1000 keV band
is 5.7 +/- 0.2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."

Dirk Grupe (Swift MOC, PSU)  reports on behalf of the 
Swift team:

We report on the Swift observations of the field of the Fermi GBM
and LAT detected GRB 140104B (Xiong, GCN Circ. 15687
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 , G. Vianello
GCN Circ. 15684
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 , respectively).  Swift started observing the 
field of GRB 140104B at 2014-January-05 08:55, 15.5 hours after 
the GBM trigger for a total of 4073s. The XRT field
covered the inner part of the GBM error circle reported by Xiong.
We found four faint X-ray sources in the XRT. The first source is
a star already present in the DSS, the other three sources are
know sources: the star TYC 5564-19-1, the AGN HE 1432-0838, and
the starburst galaxy IRAS F14325-0837. No other X-ray source was 
found.  The 3-sigma upper limit at the center of the field is 
1.4e-3  counts s^-1.

This report is an official product of the Swift team.

W. Iwakiri (RIKEN), M. Tashiro, Y. Terada, T. Yasuda, Y. Ishida, H. Ueno,
S. Sugimoto (Saitama U.), M. Yamauchi, N. Ohmori, M. Akiyama,
R. Kinoshita (Univ. of Miyazaki), M. Ohno, K. Takaki, T. Kawano,
R. Nakamura, S. Furui, Y. Fukazawa (Hiroshima U.), K. Yamaoka (Nagoya U.),
S. Sugita (Ehime U.), Y. E. Nakagawa, M. Kokubun, T. Takahashi (ISAS/JAXA),
Y. Hanabata (ICRR), Y. Urata (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo)
on behalf of the Suzaku WAM team, report:


The long GRB 140104B (Fermi-LAT detection: Vianello et al., GCN 15684
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 ;
Fermi-GBM observation: Xiong, GCN 15687
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 ) triggered the Suzaku Wide-band
All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at
17:32:13.926 UT (=T0).

The observed light curve shows a multi-peaked structure starting at
T0-14 s, ending at T0+200 s with a duration (T90) of about 185 seconds.
The fluence in 100 - 1000 keV was 1.86 (+0.83/-0.77) x 10^-5 erg/cm^2.
The 1-s peak flux measured from T0+179 s was 1.34 (+0.52/-0.45)
photons/cm^2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from
T0-14 s to T0+200 s is well fitted by a power-law with exponential cutoff model:
dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
alpha 0.42 (+1.17/-1.78), and
Epeak 351 (+75/-102) keV (chi^2/d.o.f. = 12.5/14).

All the quoted errors are at statistical 90% confidence level.

The light curves for this burst are available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html

Dirk Grupe (Swift MOC, PSU) and Phil Evans (U Leicester) report
on behalf  of the  Swift team:

We report on further Swift XRT observations of the field of the
Fermi GBM and LAT detected GRB 140104B (Xiong, GCN Circ. 15687
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 , 
G. Vianello GCN Circ. 15684
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 , respectively). 
We detected an uncatalogued X-ray source in the first Swift 
observation of the field of GRB 140104B starting at 15.5 hours
after the Fermi trigger (Grupe, GCN circ 15691
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 ) at

Ra-2000  =  14 35 01.0
Dec-2000 = -09 01 40.7

with an uncertainty of 4.0". The XRT count rate of this source
was (8.1+/-1.6)e-3 counts s^-1. Note that we misidentified this
source in the previous circular (15691) with the star TYC
5564-19-1, which however, is 2.2' away from this X-ray position. 

We re-observed this source on 2014-01-14 for 4.6 ks again with
Swift (9.5 days after the trigger). We do not detect this source
in the XRT any more, suggesting that this may be the X-ray
afterglow of GRB 140104B. The 3sigma upper limit at the position
of this source is 1.3e-3 counts s^-1. Note, however, that this is
not conclusive. This source can still be a highly variable
background AGN (see e.g. Grupe et al. 2010, ApJS, 187, 64). 

If this source is the X-ray afterglow of GRB 140104B, the X-ray
spectrum appears to be rather soft. A spectral analysis of the
X-ray data shows that the X-ray photon index is Gamma =
2.7+/-0.68 which is rather steep (see Grupe et al. 2013, ApJS,
209, 20; Evans et al., 2009, MNRAS, 397, 1177). 
The absorption column density is consistent with the
Galactic value (5.63e20 cm^-2). This steep X-ray spectral index
and the steep energy spectral index and the high fluence in the
10-1000 keV band of the burst reported by Xiong (GCN circular 
15687
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 ) suggests a low redshift nature of the burst (see Grupe et
al. 2013, ApJ, 209, 20).

However, the steep X-ray photon index of Gamma = 2.7
does not exclude a possible AGN nature of the source. In a 
matter of fact, if this is a background AGN then the steep X-ray 
spectrum suggest that this is most-likely a Narrow Line 
Seyfert 1 galaxy. This is also the type of AGN with the 
strongest X-ray variability  (e.g. Boller et al. 1996, 
Leighly 1999, Grupe et al. 2010). 



This report is an official product of the Swift team.

J.P. Osborne (U. Leicester), M. Capalbi (INAF-IASFPA), M. Perri (SSDC &
INAF-OAR), V. D'Elia (SSDC & INAF-OAR), D.N. Burrows (PSU), J. D. Gropp
(PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U.
Leicester) and	report on behalf of the Swift-XRT team: report on
behalf of the Swift-XRT team:

We have analysed 9.6 ks of XRT data for the Fermi/LAT-detected burst
GRB 140104B, from 55.4 ks to 833.9 ks after the  Fermi/LAT trigger. The
data are entirely in Photon Counting (PC) mode. The refined XRT
position is RA, Dec = 218.7543, -9.0282 which is equivalent to:

RA (J2000): 14 35 01.03
Dec(J2000): -09 01 41.5

with an uncertainty of 4.0 arcsec (radius, 90% confidence). This
position is 8.4 arcmin from the Fermi/LAT position.  We cannot
determine at the present time whether the source is fading.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020337.

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