GRB 120802A

A. Volnova (SAI MSU/IKI), L. Elenin (KIAM),  V. Rumyantsev (CrAO), 
A.Pozanenko (IKI) report on behalf of  larger GRB  follow-up collaboration:

We observed the field of  GRB 120802A (Holland et al., GCN 13555
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 ) with 
Shajn telescope of CrAO starting on Aug. 15 (UT) 23:00:26. We took several 
images in R-filter under mean seeing of 2.8".  In a stacked image we do not 
detect the object suggested as optical counterpart of GRB 120802A (Elenin et 
al., GCN 13609
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 ) up to 22.5 m. Thus we can confirm the object reported in 
(Elenin et al., GCN 13609
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 ) is most probably is an afterglow of  GRB 120802A. 
A photometry of  the filed is based on nearby USNO-B1.0 (R2) stars:

   T0+,    Filter      Exposure, OT,  UL (3 sigma)
  mid, d                  (s)

13.625    R           3540          n/d         22.5

We are grateful for CCD PL4240 provided by ISON for Shajn telescope.

L. Elenin (KIAM), A. Volnova (SAI MSU), I. Molotov (KIAM), A. Pozanenko 
(IKI) report on behalf of  larger GRB  follow-up collaboration:

We observed the field of  GRB 120802A (Holland et al., GCN 13555
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 ) with 
0.45-m telescope ?f ISON-NM observatory  starting on  Aug. 02 (UT) 08:13:18 
(Elenin et al., GCN 13556
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 ).  We took  several unfiltered images of 30 s  and 
60 s exposures starting on Aug. 02, (UT)  08:13:18.  At the edge of the 
enhanced by UVOT field astrometry  XRT error circle 
(http://www.swift.ac.uk/xrt_positions/529486)  we marginally detect a source 
in coordinates 02:59:22.35  +13:46:07.2  (uncertainty of about 0.3 arsces in 
both coordinates).   A preliminary  photometry of  co-added frames is based 
on the USNO-B1.0 (R2)  nearby  stars is following:

T_start,     T0+,           Exposure, Object,
(UT)           mid, d         (s)

08:13:18    0.06905   6360          21.2+/-0.6

We suggest the source might be an optical afterglow of GRB 120802A, however 
at that time we cannot confirm the fading origin of the source.

S. T. Holland (STScI)
reports on behalf of the Swift/UVOT team:

     The Swift/UVOT observed the field of GRB 120802A starting 70 s
after the BAT trigger (Holland et al., 2012, GCNC 13555).  Settled
observations started at 87 s.  We do not detect any source inside the
UVOT-enhanced XRT error circle (Evans et al., 2012, GCNC 13558).
Preliminary magnitudes 3-sigma upper limits at this location for the
finding charts (FC) and the co-added images, are

Filter       TSTART   TSTOP   Exp Time    3-sigma UL
----------------------------------------------------
white (FC)      87      237        147         >20.8
    u (FC)     300      550        246         >19.9
----------------------------------------------------
    v          630   16,594       1317         >20.5
    b          555     6625        332         >20.4
    u          300     6548        658         >20.5
 uvw1          678   17,567        492         >20.4
 uvm2         4504   17,499       1279         >21.2
 uvw2         4095   11,737       1279         >21.4
white           87   10,731       1268         >22.1
----------------------------------------------------

    The quoted magnitudes and upper limits have not been corrected for
the Galactic extinction along the line of sight to this burst of
E_{B-V} = 0.14 mag (Schlafly et al. 2011, ApJS, 737, 103).

T. Laskar, A. Zauderer and E. Berger (Harvard) report:

"We observed the position of GRB 120802A (Holland et al. GCN 13555
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 )
with the EVLA beginning on 2012 Aug 03.65 UT (1.32 days after the burst).
No significant radio emission is detected at the enhanced Swift-XRT
position (Evans et al. GCN 13558
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 ) to three-sigma upper limits of 39 uJy and
60 uJy, at 6 GHz and 22 GHz, respectively."

T. Sakamoto (UMBC/GSFC), D. Donato (ORAU/GSFC), N. Gehrels (GSFC),
T. Okajima (GSFC), Y. Urata (NCU)

We observed the field of GRB 120802A detected by Swift
(trigger #529486; Holland et al., GCN Circ. 13555
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 ) with the 14-inch
Goddard Robotic Telescope (GRT) located at the Goddard Geophysical
and Astronomical Observatory (http://cddisa.gsfc.nasa.gov/ggao/).

30 images of 60 sec exposures were taken in the R filter starting 
from August 2 08:37:05  (UT) about 36 minues after the trigger and 
stopped on August 2 09:08:49 (UT).  We do not detect the optical 
afterglow both in the individual images and the stacked image, which only 
combined 27 good quality images, inside the enhanced XRT position 
(Evans et al., GCN #13558
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 ).  The estimated five sigma upper limit of 
the combined image (total exposure of 1620 sec) is ~17.2 mag using 
the USNO-B1 catalog.

J.A. Kennea (PSU), M.C. Stroh (PSU), D.N. Burrows (PSU), J.P. Osborne
(U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester), V.
Mangano (INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti
(INAF-OAB/PSU) and S.T. Holland report on behalf of the Swift-XRT team:

We have analysed 7.0 ks of XRT data for GRB 120802A (Holland  et al.
GCN Circ. 13555
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 ), from 88 s to 17.6 ks after the  BAT trigger. The data
comprise 22 s in Windowed Timing (WT) mode with the remainder in Photon
Counting (PC) mode. The enhanced XRT position for this burst was given
by Evans et al. (GCN. Circ 13558).

The light curve can be modelled with an initial power-law decay with an
index of alpha=2.7 (+/-0.4), followed by a break at T+270 s to an alpha
of 0.35 (+/-0.05).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.10 (+0.21, -0.20). The
best-fitting absorption column is  1.5 (+/-0.5) x 10^21 cm^-2, in
excess of the Galactic value of 9.6 x 10^20 cm^-2 (Kalberla et al.
2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.6 x 10^-11 (5.1 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     1.5 (+/-0.5) x 10^21 cm^-2
Galactic foreground: 9.6 x 10^20 cm^-2
Excess significance: 1.8 sigma
Photon index:	     2.10 (+0.21, -0.20)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00529486.

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

N. R. Tanvir (U. Leicester), D. Fox (Penn State), J. Fynbo (DARK) 
and C. Trujllo (Gemini) report on behalf of a larger collaboration:

We observed the afterglow of GRB 120802A (Holland et al. GCN 13555
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 )
using the GMOS-N spectrograph on Gemini-North, covering a spectral 
range of about 5900A to 10000A.

Observations began at 2012-8-2 13:30 UT, about 5:30 hr post-burst.
The spectrum reveals many absorption lines including S II (1250), 
Si II (1260/1304/1526/1808), O I (1304), C II (1334), Si IV (1394/1403), 
C IV (1548/1551), Fe II (1608), Al II (1670) at a common redshift of z=3.796, 
which we believe is most likely the redshift of this burst.  We no clear
evidence of any fine-structure lines.

Note, this redshift is consistent with the absence of a strong Lyman-alpha line or 
Lyman-alpha forest since they would just fall off the blue end of our spectrum.

We also detect an intervening system at z=2.38, based on Fe II and Mg II features.

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), J. Richard 
(CRAL, U. Lyon), P. Moller (ESO), C. de Breuck (ESO),
C. Agurto (ESO) and F. Azagra (ESO) report on behalf of a 
larger collaboration:

We have observed the field of GRB 120802A (Holland et 
al. GCN 13555
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 ) using APEX/LABOCA (Chajnantor, Chile) 
in the 870um band (345 GHz) under poor weather conditions 
(PWV starting at 2.0 mm and going down to 1.4 mm at the end 
of the observation). Data acquisition started at 08:58 UT 
(58 min after the burst) and lasted for 3.5hr (2.7hr on source). 
In a preliminary analysis we do not detect any source at the GRB 
position, where we have an r.m.s. of 4mJy/beam (3-sigma limit of 
12 mJy/beam).

M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
S. T. Holland (STScI), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 120802A (trigger #529486)
(Holland, et al., GCN Circ. 13555
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 ).  The BAT ground-calculated position is
RA, Dec = 44.833, 13.762 deg, which is 
   RA(J2000)  =  02h 59m 20.0s 
   Dec(J2000) = +13d 45' 43.1" 
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 56%.
 
The mask-weighted light curve shows a small precursor peak from ~T-40 to ~T-33 sec,
then a fast rise at ~T-2 sec, peaking at ~T+2 sec and decaying exponentially
with a second peak peaking at ~T+8 sec and ending at ~T+45 sec.
T90 (15-350 keV) is 50 +- 31 sec (estimated error including systematics).
 
The time-averaged spectrum from T-35.68 to T+28.02 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.21 +- 0.47, 
and Epeak of 57.2 +- 19.4 keV (chi squared 52.25 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 1.9 +- 0.3 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+7.94 sec in the 15-150 keV band is
3.0 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.84 +- 0.10 (chi squared 58.45 for 57 d.o.f.).  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/529486/BA/

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

Using 539 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 120802A, 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 = 44.84185, +13.76805 which is equivalent
to:

RA (J2000): 02h 59m 22.04s
Dec (J2000): +13d 46' 05.0"

with an uncertainty of 2.8 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.

H. Levato and C. Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

C. Mallamaci, C. Lopez and F. Podest
Observatorio Astronomico Felix Aguilar (OAFA)

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

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

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

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

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


MASTER-ICATE robotic very wide field cameras (FOV=2x384 square degrees, D=72mm, 
f/1.2, 1 pix = 22 arcsec, http://observ.pereplet.ru) located in Argentina 
(Observatorio Astronomico Felix Aguilar, http://93.180.27.230:8080/) were 
pointed to the GRB120802A (Holland et al, GCN 13555
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 ) 21 s after notice 
time and 43 s after GRB time at 2012-08-02 
08:01:34 UT under full Moon. We haven`t found optical transient  within 
SWIFT error-box  our first (5 s exposure) set.
The 5-sigma upper limit has been about 10.6 
mag The 5-sigma upper limit on coadd first 42 images is about 12.0 mag.

Our cameras are continuously imaging the sky with 5 sec exposures.

This message can be cited.

L. Elenin (KIAM), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of 
larger GRB  follow-up collaboration:

We observed the field of  GRB 120802A (Holland et al., GCN 13555
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 ) with 
0.45-m telescope �f ISON-NM observatory  starting on  Aug. 02 (UT) 08:13:18, 
i.e. 12.5 minutes after burst  trigger.  We took  several unfiltered images 
of 30 s exposure.  We do not detect any source within XRT error circle 
(Holland et al., GCN 13555
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 ) in any co-added frames.   The preliminary 
photometry of  co-added frames is based  on the USNO-B1.0 (R2)  nearby 
stars:

T_start,     Exposure, OT,  Upper Limit (3sigma)
(UT)           (s)

08:13:18    10x30       n/d    17.5
08:13:18    20x30       n/d    17.7
08:13:18    29x30       n/d    18.1

Observations are continued.

S. T. Holland (STScI), W. H. Baumgartner (GSFC/UMBC),
A. P. Beardmore (U Leicester), P. A. Evans (U Leicester),
C. Guidorzi (U Ferrara), K. L. Page (U Leicester),
D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC) and
T. Sakamoto (NASA/UMBC) report on behalf of the Swift Team:

At 08:00:51 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 120802A (trigger=529486).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 44.849, +13.757 which is 
   RA(J2000) = 02h 59m 24s
   Dec(J2000) = +13d 45' 26"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows two overlapping FRED 
peaks with a duration of about 20 sec.  The peak count rate
was ~3500 counts/sec (15-350 keV), at ~8 sec after the trigger. 

The XRT began observing the field at 08:02:16.3 UT, 84.8 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 44.84120, 13.76787 which
is equivalent to:
   RA(J2000)  = 02h 59m 21.89s
   Dec(J2000) = +13d 46' 04.3"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 47 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. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 9.65
x 10^20 cm^-2 (Kalberla et al. 2005). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 86 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
0.15. 

Burst Advocate for this burst is S. T. Holland (sholland AT stsci.edu). 
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.)