GRB 120819A

A. P. Beardmore (U Leicester), S. D. Barthelmy (GSFC),
J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC),
F. E. Marshall (NASA/GSFC), C. J. Mountford (U Leicester),
C. Pagani (U Leicester) and K. L. Page (U Leicester) report on behalf
of the Swift Team:

At 13:10:14 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 120819A (trigger=531428).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 235.888, -7.305 which is 
   RA(J2000)  =  15h 43m 33s
   Dec(J2000) = -07d 18' 16"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows several peaks
with a duration of about 30 sec.  The peak count rate
was ~1600 counts/sec (15-350 keV), at ~5 sec after the trigger. 

The XRT began observing the field at 13:12:50.5 UT, 156.2 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 235.90848, -7.30910 which is equivalent
to:
   RA(J2000)  = 15h 43m 38.04s
   Dec(J2000) = -07d 18' 32.8"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 74 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 in excess of the Galactic value (8.93 x
10^20 cm^-2, Kalberla et al. 2005), with an excess column of 3.4
(+2.74/-2.85) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 158 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 77% 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
0.17. 

Burst Advocate for this burst is A. P. Beardmore (apb 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.)

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


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

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

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

  V.Krushinski, I.Zalozhnih,  A. Popov
  Ural Federal University, Kourovka

  Hugo Levato and Carlos Saffe
  Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

  Claudio Mallamaci, Carlos Lopez and Federico Podest
  Observatorio Astronomico Felix Aguilar (OAFA)


MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Blagoveschensk was pointed to the  GRB120819A (Beardmore et 
al., GCN 13681
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 ) sec after GRB time at 2012-08-19 13:12:10.052 UT.
On our first (20s exposure) set we 
haven`t found optical transient  within SWIFT error-box.
The 5-sigma upper limit has been about 16.5 mag
The reduction is continuated.
The message may be cited.

D. Malesani (DARK/NBI), G. Leloudas (OKC Stockholm and DARK/NBI), D. Xu (WIS), J. P. U. Fynbo (DARK/NBI), P. Jakobsson (Univ. Iceland), S. Geier (NOT and DARK/NBI) report on behalf of a larger collaboration:

We observed the field of GRB 120819A (Beardmore et al., GCN 16381
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 ) with the NOT equipped with ALFOSC. Observations were carried out in the R and z bands, for a total of 20 and 40 min exposure, respectively.

Within the current XRT position (see http://www.swift.ac.uk/xrt_positions/index.php), we detect a source at the following coordinates (J2000):

RA = 15:43:37.84
Dec = -07:18:32.9

with an error of about 0.5". Assuming R = 18.05 for the nearby USNO star at RA = 15:43:38.183, Dec = -07:17:51.72, the object has R = 23.0 +- 0.1. The mean time of the R-band observation is Aug 19.913 UT, that is 8.75 hr after the GRB.

Given the faintness of the source and the lack of information on its temporal behaviour, we cannot state whether this object is related to GRB 120819A.

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

Using 2836 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 120819A, 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 = 235.90756, -7.30909 which is equivalent
to:

RA (J2000): 15h 43m 37.81s
Dec (J2000): -07d 18' 32.7"

with an uncertainty of 1.8 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.

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 the MITSuME collaboration:

We observed the field of GRB 120819A (Beardmore et al., GCNC 13681)
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 2012-08-19 13:12:11 UT (~2.0 min after the burst)
We did not find any new point source within the enhanced XRT circle
(Beardmore et al., GCNC 13681) in all the three bands.
We also could not detect the previously reported afterglow (Malesani et al.,
GCNC 13683).


Three sigma upper limits of the OT are listed below. We used
GSC2.3 catalog for flux calibration.

T0+[day]   MID-UT   T-EXP[sec]    g'     Rc     Ic
------------------------------------------------------
0.01186    13:27:19    1620.0   >19.1  >19.4  >18.8
------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]

D. Kuroda (OAO, NAOJ),  H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ),
K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima),
K. Ohta (Kyoto) and N. Kawai(Tokyo Tech)
report on behalf of the MITSuME collaboration:

We observed the field of GRB 120819A (Beardmore et al., GCNC 13681)
with the optical three color (g', Rc and Ic) CCD camera attached
to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory.

The observation started on 2012-08-19 13:13:11 UT, (~3.0 min after the burst)
We did not find any new point source within the enhanced XRT circle
(Beardmore et al., GCNC 13681) in all the three bands.
We also could not detect the previously reported afterglow (Malesani et al.,
GCNC 13683).


Three sigma upper limits of the OT are listed below. We used
GSC2.3 catalog for flux calibration.

T0+[day]   MID-UT   T-EXP[sec]    g'     Rc     Ic
------------------------------------------------------
0.01544    13:32:28    1980.0   >21.5  >21.6  >20.3
------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]

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

We have analysed 10 ks of XRT data for GRB 120819A (Beardmore  et al.
GCN Circ. 13681
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 ), from 159 s to 23.0 ks after the  BAT trigger. The
data comprise 67 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 13684).

The light curve can be modelled with  a power-law decay with a decay
index of alpha=1.75 (+0.12, -0.09).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index	of 1.7 (+/-0.4). The
best-fitting absorption column is  3.3 (+2.0, -1.5) x 10^21 cm^-2, in
excess of the Galactic value of 8.9 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 4.2 x 10^-11 (6.0 x 10^-11) erg
cm^-2 count^-1. 

A summary of the WT-mode spectrum is thus:
Total column:	     3.3 (+2.0, -1.5) x 10^21 cm^-2
Galactic foreground: 8.9 x 10^20 cm^-2
Excess significance: 2.6 sigma
Photon index:	     1.7 (+/-0.4)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00531428.

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

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

We observed the field of GRB 120819A (Swift trigger 531428; Beardmore et 
al., GCN 13681
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 ) simultaneously in g'r'i'z'JHKs with GROND (Greiner et 
al. 2008, PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La 
Silla Observatory (Chile).

Observations started at 23:46 UT on 2012-08-19, 10.5 hrs after the GRB 
trigger. Based on co-added images spanning 2 hours taken at a mean 
airmass of 1.3 and seeing of 1.6", we confirm the presence of the NOT 
afterglow candidate (Malesani et al., GCN 13683
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 ). We derive preliminary 
magnitudes (all AB system) of this source:

   g' = 23.7 +- 0.1
   r' = 23.1 +- 0.1
   i' = 22.5 +- 0.1
   z' = 22.2 +- 0.1
   J  = 21.5 +- 0.3
   H  > 20.2
   Ks > 20.1

We note that although these magnitudes do not suggest fading, the large 
uncertainties from the USNO calibration used by Malesani et al. do not 
preclude this possibility.

The consistency with the enhanced XRT position (Evans et al., GCN 
13684
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 ), combined with the power-law like SED, confirm that this source 
is the afterglow of GRB 120819A.

The g' band detection does not suggest substantial Ly-alpha or dust 
effects, implying that the redshift of this burst is likely smaller than 
3.0.

The magnitudes are derived based on GROND zeropoints (g'r'i'z') and 
2MASS stars (JHK). The magnitudes are not corrected for the expected 
Galactic reddening along the line of sight of E_(B-V)= 0.16 mag 
(Schlegel et al. 1998).

T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
A. P. Beardmore (U Leicester), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), G. Sato (ISAS), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
 
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 120819A (trigger #531428)
(Beardmore, et al., GCN Circ. 13681
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 ).  The BAT ground-calculated position is
RA, Dec = 235.887, -7.304 deg, which is 
   RA(J2000)  =  15h 43m 32.8s 
   Dec(J2000) = -07d 18' 13.5" 
with an uncertainty of 2.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 30%.
 
The mask-weighted light curve shows multiple peaks starting at ~T-2 sec,
with the largest peak at ~T+0 sec, and returning to baseline at ~T+180 sec.
T90 (15-350 keV) is 71 +- 21 sec (estimated error including systematics).
 
The time-averaged spectrum from T+4.42 to T+82.88 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.49 +- 0.23.  The fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+6.20 sec in the 15-150 keV band
is 0.8 +- 0.3 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/531428/BA/

U.Quadri, L.Strabla, R.Girelli and A.Quadri report:

We imaged the field of GRB 120819A detected 
by SWIFT(trigger 531428) with the robotic 
telescope of (IAU station 565) Bassano Bresciano 
Observatory, Italy.

The observations started 6h 35min. after the 
GRB trigger(delay due to expecting the night)
with our Schmidt telescope D=400mm F/D=3.1.

Weather conditions were good.

We co-added 2 series of 15 unfiltered CCD exposures of 120s each.

We did not appear any reasonable optical counterpart 
in the error box of the XRTcandidate (Beardmore et al., GCNC 13681) 
at our limiting magnitude.

Start      End       M.lim.
395min     454min    19.5

Magnitudes were estimated with the USNO-B1 cat. 


The message may be cited.

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

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


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

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

V.Krushinski, I.Zalozhnih,  A. Popov
Ural Federal University, Kourovka

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)


MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in 
Blagoveschensk was pointed to the  GRB120819A (Beardmore et al., GCN 
13681
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 ) 25 sec after notice time and 115 sec after GRB time at 2012-08-19 
13:12:10.052 UT (Yurkov et. al, GCN 13682
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 ).

Unfiltered observations were carried out on high zenith distance (78 deg. 
at the observations beginning moment and above).
The unfiltered magnitude is calibrated relative to USNO B1.0 (0.8 R + 0.2 
B).
After the data processing  we have the following results:


             Start      Middle    Stop    T-Tgrb Coadd Exp.time  Limit
2012-08-19 13:12:10  13:12:20  13:12:30    125     1       20   16.5
2012-08-19 13:12:10  13:15:00  13:17:51    285     6      140   17.8
2012-08-19 13:19:08  13:39:35  14:00:02   1785    10     1800   18.5

The message may be cited.

F. E. Marshall (NASA/GSFC) and A. P. Beardmore (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 120819A
158 s after the BAT trigger (Beardmore et al., GCN Circ. 13681
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 ).
No optical afterglow consistent with the optical position
(Malesani et al. GCN Circ. 13683
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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           158          308          147         >21.1
white              158         5439          541         >21.7
v                 4214        22619         1278         >20.9
b                 3598        11864         1164         >21.1
u                 4829        17638         1858         >21.6
w1                4625        16836         1998         >21.4
m2                4418        22980         1629         >21.7
w2                4009        21706         1279         >21.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.17 in the direction of the burst
(Schlegel et al. 1998).

Yu. Krugly, V. Chiorny (Institute of Astronomy of Kharkiv National 
University), A. Volnova (SAI MSU), I. Molotov (KIAM), A. Pozanenko (IKI) 
report on behalf of larger collaboration:

We observed the afterglow of GRB 120819A (Beardmore  et al. GCN 13681
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 ) with 
0.7m  telescope of Institute of Astronomy, Kharkiv National Univ. starting 
on Aug. 19 (UT) 18:27:41. A set of images were taken in R-filter.   We do 
not detect optical afterglow (Malesani et al. GCN 13683
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 ; Sudilovsky et 
al.GCN 13688). The photometry is based on the nearby USNO-B1.0 (R2) stars:

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

0.22102    R        2160          n/d    20.3