GRB 140302A

C. Pagani (U Leicester), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), V. D'Elia (ASDC),
C. B. Markwardt (NASA/GSFC), A. Maselli (INAF-IASFPA),
K. L. Page (U Leicester), M. H. Siegel (PSU) and
R. L. C. Starling (U Leicester) report on behalf of the Swift Team:

At 08:12:58 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 140302A (trigger=589685).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 253.842, -12.865, which is 
   RA(J2000)  =  16h 55m 22s
   Dec(J2000) = -12d 51' 53"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows several peaks
with a total duration of about 35 sec.  The peak count rate
was ~5300 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 08:14:10.9 UT, 72.2 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 253.85859, -12.87891 which
is equivalent to:
   RA(J2000)  = 16h 55m 26.06s
   Dec(J2000) = -12d 52' 44.1"
with an uncertainty of 4.1 arcseconds (radius, 90% containment). This
location is 76 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 1.46
x 10^21 cm^-2 (Kalberla et al. 2005). 

The initial flux in the 2.5 s image was 1.49e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 80 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.52. 

Burst Advocate for this burst is C. Pagani (cp232 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.)

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

Using  promptly downlinked XRT event data for GRB 140302A, we find an
enhanced XRT position of the afterglow: RA, Dec: 253.8593, -12.8788
which is equivalent to:
   RA (J2000)  = 16 55 26.23
   Dec (J2000) = -12 52 43.7
with an uncertainty of 2.6 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/589685.

Position enhancement is is described by Goad et al. (2007, A&A, 476,
1401) and Evans et al. (2009, MNRAS, 397, 1177).

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

J. Elliott (MPE Garching), S. Schmidl (TLS Tautenburg), and J. Greiner
(MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 140302A (Swift trigger 589685; Pagani et al.,
GCN #15901
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 ) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,
PASP 120, 405) mounted at the 2.2m MPG telescope at ESO La Silla
Observatory (Chile).

Observations started at 08:21:12 UT on the 2nd March 2014, 8.2 min after
the GRB trigger. They were performed at an average seeing of 1.5" and at
an average airmass of 1.2.

We find a faint point source inside the enhanced XRT error
circle given in Evans et al. (GCN #15902
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 )

RA (J2000.0) = 16:55:26.30
DEC (J2000.0) = -12:52:42.2

with an uncertainty of 0.5" in each coordinate.

Based on a total exposure of 1936 sec in r', at a mid-time of 0.65
hrs after the burst, we measure the following preliminary magnitude (in AB):

r = 23.7 +/- 0.2 mag.

No statement about fading can be made at this stage.

Given magnitude is calibrated against GROND zeropoint and is not
corrected for the expected Galactic foreground extinction corresponding to
a reddening of E_(B-V) = 0.52 mag in the direction of the burst (Schlegel
et al. 1998).

J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 478 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 140302A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 253.85872, -12.87823 which is equivalent
to:

RA (J2000): 16h 55m 26.09s
Dec (J2000): -12d 52' 41.6"

with an uncertainty of 2.3 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

This circular was automatically generated, and is an official product of the
Swift-XRT team.

S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC),
C. B. Markwardt (GSFC), C. Pagani (U Leicester), D. M. Palmer (LANL),
T. Sakamoto (AGU), 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+303 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 140302A (trigger #589685)
(Pagani, et al., GCN Circ. 15901
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 ).  The BAT ground-calculated position is
RA, Dec = 253.862, -12.875 deg, which is 
   RA(J2000)  =  16h 55m 26.8s 
   Dec(J2000) = -12d 52' 29.8" 
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 82%.
 
The mask-weighted light curve shows a sharp rise starting at ~T-0.1 sec,
peaking at ~T+0.2 sec, and a roughly exponential decay with several small
peaks riding on top, finally returning to baseline at ~T+190 sec.
T90 (15-350 keV) is 87.5 +- 11.4 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.09 to T+106.25 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.09 +- 0.09.  The fluence in the 15-150 keV band is 2.7 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-0.10 sec in the 15-150 keV band
is 1.7 +- 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/589685/BA/

J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), V. D'Elia
(ASDC), A. Maselli  (INAF-IASFPA), A. Melandri (INAF-OAB), D.N. Burrows
(PSU), J.A. Kennea (PSU), V. Mangano (PSU) and C. Pagani report on
behalf of the Swift-XRT team:

We have analysed 6.0 ks of XRT data for GRB 140302A (Pagani  et al. GCN
Circ. 15901
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 ),  from 78 s to 23.2 ks after the  BAT trigger. The data
comprise 136 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Osborne et al. (GCN Circ. 15902
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 ).

The light curve can be modelled with an initial power-law decay with an
index of alpha=1.62 (+0.22, -0.23), followed by a break at T+183 s to
an alpha of 4.0 (+/-0.4).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index	of 1.08 (+0.16, -0.15). The
best-fitting absorption column is  3.1 (+1.0, -0.9) x 10^21 cm^-2, in
excess of the Galactic value of 1.5 x 10^21 cm^-2 (Kalberla et al.
2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 6.8 x 10^-11 (7.7 x 10^-11) erg
cm^-2 count^-1. 

A summary of the WT-mode spectrum is thus:
Total column:	     3.1 (+1.0, -0.9) x 10^21 cm^-2
Galactic foreground: 1.5 x 10^21 cm^-2
Excess significance: 3.2 sigma
Photon index:	     1.08 (+0.16, -0.15)

If the light curve continues to decay with a power-law decay index of
4.0, the count rate at T+24 hours will be 1.9 x 10^-10 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.3 x
10^-20 (1.4 x 10^-20) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00589685.

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

G. Fitzpatrick (UCD) reports on behalf of the Fermi GBM Team:

At 08:12:58.89 UT on 02 March 2014, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 140302A (trigger 415440781/140302342), which was
also
detected by Swift (Pagani et al., GCN 15901
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 ). The GBM on-ground location
is consistent with the Swift/XRT position (Pagani et al., GCN 15901
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 ).

The GBM light curve consists of a single peak
with a duration (T90) of about 64 s (50-300 keV).
The time-averaged spectrum from T0 s to T0+64 s is
adequately fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.49 +/- 0.1 and
the cutoff energy, parameterized as Epeak, is 462 +/- 53 keV.

The event fluence (10-1000 keV) in this time interval is
(1 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0 s in the 10-1000 keV band is 3 +/- 0.2 ph/s/cm^2.

The main emission is preceded by an apparent precursor event with an
approximate
duration of 20 s. This event has been tentatively associated with the GRB
based on the
location derived by GBM.

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

D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ),
S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto)
and N. Kawai(Tokyo Tech)
report on behalf of MITSuME collaboration:

We observed the field of GRB 140302A (Pagani et al., GCNC 15901)
with the optical three color (g', Rc and Ic) CCD camera attached
to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.

The observation started on 2014-03-02 19:19:00 UT (~11.1 h after the burst).
We could not detect the previously reported afterglow (Elliot et al., GCNC
15903) in all the three bands.

Three sigma upper limits of the OT are listed below.
We used GSC 2.3 catalog for flux calibration.

#T0+[day]  MID-UT    T-EXP[sec]   g'     Rc     Ic
-----------------------------------------------------
0.48800    19:55:41    2400.0   >19.6  >19.4  >18.7
-----------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]

M. H. Siegel (PSU) and C. Pagani (U Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 140302A
80 s after the BAT trigger (Pagani et al., GCN Circ. 15901
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 ).
No optical afterglow consistent with the optical position
(Elliott et al. GCN Circ. 15903
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 )
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white (fc)          80          230          147         >20.5
white               80          593          167         >20.6
white            10575        11481          590         >21.1
v                  624          643           19         >18.3
v                16940        17847          590         >19.4
b                  549          569           19         >19.3
b                 9662        10569          590         >20.5
u (fc)             293          543          246         >19.7
uvw1               672          692           19         >19.0
uvm2             17853        17993          137         >18.9
uvw2             11487        12232          732         >20.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.52 in the direction of the burst
(Schlegel et al. 1998).

J. Elliott (MPE Garching), S. Schmidl (TLS Tautenburg), J.Greiner, J. F.
Graham, M. Tanga (all MPE Garching) report on behalf of the GROND team:

We re-observed the field of GRB 140302A (Swift trigger 589685; Pagani et
al., GCN #15901
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 ) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at La Silla
Observatory (Chile).

Observations started at 07:18 UT on 4th March 2014, 2 days after the GRB
trigger. They were performed at an average seeing of 1.1" and at an
average airmass of 1.3.

We no longer detect the source noted in our previous observations (Elliott
et al.; GCN #15903
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 ) that had a magnitude of r' = 23.7 +/- 0.2 mag. For a
total exposure of 1.2 hours we obtain an upper limit (AB) of r' > 25.2 mag
and confirm this as the afterglow of GRB 140302A.

The given limit is derived based on calibrating the image against GROND
zeropoints and is not corrected for the Galactic foreground extinction
corresponding to a reddening of E(B-V)= 0.52 mag in the direction of the
burst (Schlegel et al. 1998).

Klotz A., Turpin D. (IRAP-CNRS-OMP),
Boer M., Gendre B., Siellez K., Dereli H., Bardho O. (UNS-CNRS-OCA),
Atteia J.L. (IRAP-CNRS-OMP) report:

We imaged the field of GRB 140302A detected by SWIFT
(trigger 589685) with the TAROT robotic telescope (D=25cm)
located at the European Southern Observatory,
La Silla observatory, Chile.

The observations started 36.5s after the GRB trigger
(14.3s after the notice). The elevation of the field increased from
48 degrees above horizon and weather conditions
were excellent.

The first image is trailed with a duration of 60.0s
(see the description in Klotz et al., 2006, A&A 451, L39).
We do not detect any OT with a limiting magnitude of:
t0+36.5s to t0+96.5s : Rlim = 15.9

The second image is 60.0s exposure in tracking mode.
No afterglow candidate is seen:
t0+140s to t0+200s : Rlim = 19.0

The next images does not show the candidate identified
by Elliott et al. (GCNC 15903) at R=23.7 8.2 min after
the trigger.

Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.