GRB 140320A

J. K. Cannizzo (NASA/UMBC), J. A. Kennea (PSU),
A. Y. Lien (NASA/GSFC/ORAU), C. J. Mountford (U Leicester),
D. M. Palmer (LANL) and B. Sbarufatti (INAF-OAB/PSU) report on behalf
of the Swift Team:

At 02:12:45 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 140320A (trigger=592544).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 281.857, -11.173 which is 
   RA(J2000) = 18h 47m 26s
   Dec(J2000) = -11d 10' 21"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a double-peaked
structure with two peaks separated by ~140 sec and a total duration 
of about 150 sec.  The peak count rate
was ~3700 counts/sec (15-350 keV), at ~0 sec after the trigger. 

No source was detected in 57 s of promptly downlinked data. We are
waiting for the full dataset to detect and localise the XRT
counterpart. 

Due to partial real-time telemetry, no further information is
available at this time.  However the burst was also detected
by the Fermi-GBM instrument, verifying its reality. 
More details will be available following the next ground pass 
telemetry dump. 

Burst Advocate for this burst is J. K. Cannizzo (cannizzo AT milkyway.gsfc.nasa.gov). 
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.)

G. Younes (USRA/MSFC) and V. Connaughton (UAH) report on behalf of the Fermi GBM Team:

"At 02:12:46.11 UT on 19 March 2014, the Fermi Gamma-Ray Burst Monitor
Triggered and located GRB 140320A (trigger 416974369/140320092), which
was  also detected by Swift (Cannizzo et al. 2014, GCN 16000
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 ).

The double peaked structure seen with BAT, with ~150 s separation, and
reported by Cannizzo et al. is also visible with FERMI/GBM, however, a
location analysis with GBM shows that the two peaks are unrelated. The
first peak (trigger peak) is most likely due to a short/hard GRB located at
RA~284.6 DEC~-5.0 deg, consistent with the BAT location. The second peak,
150 s after the trigger, is much softer and locates at RA~265.0 DEC~-28.0,
the location of the bursting pulsar GRO J1744-28, which is currently active.

Hence, we encourage multi-wavelength follow-up observations of this candidate short/hard GRB.�

K.L. Page, C. Pagani (U. Leicester) and J.K. Cannizzo (NASA/UMBC) report
on behalf of the Swift-XRT team:

We have analysed 5 ks of XRT data for GRB 140320A (Cannizzo et al. GCN
Circ. 16000
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 ), from 93 s to 11.8 ks after the BAT trigger. The data are
entirely in Photon Counting (PC) mode. We detect a faint, uncatalogued
X-ray source with a mean count rate of (5.9 +/- 1.3) x 10^-3 count s^-1,
at a position of RA, Dec = 281.85583, -11.19333, which is equivalent to

RA(J2000) =   18 47 25.4
Dec(J2000) = -11 11 36.9

with an uncertainty of 5.3 arcsec (radius, 90% confidence). This is 73
arcsec from the initial BAT position, within the BAT error circle. We
cannot determine at this time whether the source is fading.

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

K.L. Page, C. Pagani, P.A. Evans and M.R. Goad (U. Leicester) report on
behalf of the Swift-XRT team:

Using 715 s of XRT Photon Counting mode data and 1 UVOT images, 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 =
281.85530, -11.19412 which is equivalent to:

RA (J2000):  18 47 25.27
Dec (J2000): -11 11 38.8

with an uncertainty of 4.9 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 is an official product of the Swift-XRT team.

G. Younes (USRA/MSFC), V. Connaughton (UAH), C. Meegan (UAH),
and A. von Kienlin (MPE) report on behalf of the Fermi GBM Team:

"At 02:12:46.11 UT on 20 March 2014, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 140320A (trigger 416974369/140320092),
which was also detected by Swift (Cannizzo et al. 2014, GCN 16000
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 ).
The GBM on-ground location, using the Fermi GBM trigger
data, is consistent with the Swift/BAT location.

The angle to the Fermi LAT boresight is 24 deg. using the Swift location.

The GBM light curve consists of a single pulse with a
duration (T90) of 1 s (50-300 keV).
The time-averaged spectrum from T0-0.32 to T0+0.704 s is
well fit by a simple power law function with index of -1.5 +/- 0.1.

The event fluence (10-1000 keV) in this time interval is
(4.0 +/- 0.5) E-07 erg/cm^2. The 0.064-sec peak photon flux measured
starting from T0-0.128 s in the 10-1000 keV band
is 5.0 +/- 1.0 ph/s/cm^2.

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

K.L. Page, C. Pagani, P.A. Evans (U. Leicester) & J.K. Cannizzo
(NASA/UMBC) report on behalf of the Swift-XRT team:

We have now analysed 9.8 ks of Swift-XRT data for GRB 140320A, between 93
s and 33.5 ks after the trigger. The X-ray source given by Page, Pagani &
Cannizzo in GCN Circ. 16010
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  has now faded, with a 3-sigma upper limit on
the count rate centred at 27 ks after the trigger of 1.2 x 10^-3 count
s^-1. We therefore confirm this source as the X-ray afterglow of GRB
140320A.

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

S. R. Oates (UCL-MSSL) and J. K. Cannizzo (NASA/UMBC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 140320A
3723 s after the BAT trigger (Cannizzo et al., GCN Circ. 16000
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 ).
No optical afterglow consistent with the enhanced XRT position
(Page et al., GCN Circ 16011
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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

v                 3723         5358          393         >19.2
b                 4543        10186         1149         >20.8
u                 4338         5973          393         >19.7
w1                4133         5768          393         >19.8
m2                3928         5563          393         >20.0
w2                3518         5153          393         >20.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.51 in the direction of the burst
(Schlegel et al. 1998).

D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. K. Cannizzo (NASA/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC), C. B. Markwardt (GSFC),
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+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 140320A (trigger #592544)
(Cannizzo, et al., GCN Circ. 16000
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 ).  The BAT ground-calculated position is
RA, Dec = 281.843, -11.188 deg which is
   RA(J2000)  =  18h 47m 22.4s
   Dec(J2000) = -11d 11' 18.5"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 88%.

The mask-weighted light curve shows a double short-peaked structure starts
at ~T-0.1 s. The second peak starts immediately at the end of the first peak
at ~T+0.3 s, and ends at ~T+0.4 s. T90 (15-350 keV) is 0.45 +- 0.07 sec
(estimated error including systematics).

The time-averaged spectrum from T-0.08 to T+0.44 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.24 +- 0.36.  The fluence in the 15-150 keV band is 4.9 +- 1.0 x 10^-8 erg/cm2.
The 1-sec peak photon flux measured from T-0.32 sec in the 15-150 keV band
is 0.6 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

As noted in the Fermi/GBM circular (Younes et al.; GCN Circ. 16001
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 ), the pulse
at ~T+140 s initially reported in Cannizzo, et al. (GCN Circ. 16000
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 ) is
originated from a different source, the bursting pulsar GROJ1744-28.
Therefore, GRB 140320A is a short burst.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/592544/BA/

Owen Littlejohns (ASU), Nat Butler (ASU), Alan M. Watson (UNAM),
Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer
(UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska
(UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora
Troja (GSFC), Enrico Ramirez-Ruiz (UCSC), José A. de Diego (UNAM),
Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos Román-Zúñiga
(UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:

We observed the field of GRB 140320A (Cannizzo, et al., GCN 16000
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 ) with
the Reionization and Transients Infrared Camera (RATIR; www.ratir.org)
on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico
Nacional on Sierra San Pedro Mártir from 2014/03 21.42 to 2014/03 21.51
UTC (31.77 to 33.94 hours after the BAT trigger), obtaining a total of
1.40 hours exposure in the r and i bands and 0.56 hours exposure in the
Z, Y, J, and H bands.

For a source within the Swift-XRT error circle, in comparison with 2MASS,
we obtain the following upper limits (3-sigma):

  r     > 22.70
  i     > 22.38
  Z     > 21.23
  Y     > 21.27
  J     > 20.82
  H     > 20.24

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.

We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.