Gamma-ray Burst 130903A

(All information courtesy of the instrument teams.)

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Tue 03 Sep 13 00:47:38 UT
NOTICE_TYPE:    INTEGRAL Wakeup
TRIGGER_NUM:    6930,   Sub_Num: 0
GRB_RA:          82.1450d {+05h 28m 35s} (J2000),
                 82.3200d {+05h 29m 17s} (current),
                 81.5051d {+05h 26m 01s} (1950)
GRB_DEC:         -0.1139d {-00d 06' 49"} (J2000),
                 -0.1036d {-00d 06' 12"} (current),
                 -0.1535d {-00d 09' 12"} (1950)
GRB_ERROR:      2.87 [arcmin, radius, statistical only]
GRB_INTEN:      12.14 [sigma]
GRB_TIME:       2852.32 SOD {00:47:32.32} UT
GRB_DATE:       16538 TJD;   246 DOY;   13/09/03
SC_RA:           79.55 [deg] (J2000)
SC_DEC:          -7.23 [deg] (J2000)
SUN_POSTN:      162.18d {+10h 48m 44s}   +7.56d {+07d 33' 19"}
SUN_DIST:        79.97 [deg]   Sun_angle= 5.3 [hr] (West of Sun)
MOON_POSTN:     133.57d {+08h 54m 18s}  +12.18d {+12d 11' 06"}
MOON_DIST:       52.31 [deg]
GAL_COORDS:     203.25,-18.40 [deg] galactic lon,lat of the burst
ECL_COORDS:      81.44,-23.32 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Time_Scale=10.0000 and Time_Error=10.0000.  
COMMENTS:       Possibly real GRB event

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 03 Sep 13 00:47:57 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      45
TRIGGER_NUM:     399862055
GRB_RA:           93.133d {+06h 12m 32s} (J2000),
                  93.262d {+06h 13m 03s} (current),
                  92.663d {+06h 10m 39s} (1950)
GRB_DEC:         -31.433d {-31d 25' 59"} (J2000),
                 -31.438d {-31d 26' 14"} (current),
                 -31.419d {-31d 25' 08"} (1950)
GRB_ERROR:       28.93 [deg radius, statistical plus systematic]
GRB_INTEN:       40 [cnts/sec]
DATA_SIGNIF:     4.70 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        16538 TJD;   246 DOY;   13/09/03
GRB_TIME:        2852.37 SOD {00:47:32.37} UT
GRB_PHI:           0.00 [deg]
GRB_THETA:         5.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.70
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   3%  Generic Transient
DETECTORS:       1,1,0, 0,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       162.18d {+10h 48m 44s}   +7.56d {+07d 33' 19"}
SUN_DIST:         76.37 [deg]   Sun_angle= 4.6 [hr] (West of Sun)
MOON_POSTN:      133.58d {+08h 54m 18s}  +12.18d {+12d 11' 03"}
MOON_DIST:        58.27 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:      238.28,-21.47 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       94.64,-54.82 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 72.80,13.18 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the INTEGRAL event (trignum=6930).

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Tue 03 Sep 13 00:50:37 UT
NOTICE_TYPE:    INTEGRAL Refined
TRIGGER_NUM:    6930,   Sub_Num: 1
GRB_RA:          82.1364d {+05h 28m 33s} (J2000),
                 82.3114d {+05h 29m 15s} (current),
                 81.4965d {+05h 25m 59s} (1950)
GRB_DEC:         -0.1190d {-00d 07' 07"} (J2000),
                 -0.1087d {-00d 06' 30"} (current),
                 -0.1586d {-00d 09' 30"} (1950)
GRB_ERROR:      2.62 [arcmin, radius, statistical only]
GRB_INTEN:      22.48 [sigma]
GRB_TIME:       2886.32 SOD {00:48:06.32} UT
GRB_DATE:       16538 TJD;   246 DOY;   13/09/03
SC_RA:           79.55 [deg] (J2000)
SC_DEC:          -7.23 [deg] (J2000)
SUN_POSTN:      162.18d {+10h 48m 44s}   +7.55d {+07d 33' 17"}
SUN_DIST:        79.98 [deg]   Sun_angle= 5.3 [hr] (West of Sun)
MOON_POSTN:     133.60d {+08h 54m 24s}  +12.18d {+12d 10' 41"}
MOON_DIST:       52.34 [deg]
GAL_COORDS:     203.25,-18.41 [deg] galactic lon,lat of the burst
ECL_COORDS:      81.43,-23.32 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Time_Scale=40.0000 and Time_Error=40.0000.  
COMMENTS:       Possibly real GRB event  
COMMENTS:           
COMMENTS:        NOTE: This INTEGRAL event is temporally(34.0<100sec) coincident with the FERMI_GBM event (trignum=399862055).

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Tue 03 Sep 13 01:38:59 UT
NOTICE_TYPE:    INTEGRAL Offline
TRIGGER_NUM:    6930,   Sub_Num: 2
GRB_RA:          82.1333d {+05h 28m 32s} (J2000),
                 82.3083d {+05h 29m 14s} (current),
                 81.4935d {+05h 25m 58s} (1950)
GRB_DEC:         -0.1250d {-00d 07' 29"} (J2000),
                 -0.1147d {-00d 06' 52"} (current),
                 -0.1646d {-00d 09' 52"} (1950)
GRB_ERROR:      1.50 [arcmin, radius, statistical only]
GRB_INTEN:      22.48 [sigma]
GRB_TIME:       2886.32 SOD {00:48:06.32} UT
GRB_DATE:       16538 TJD;   246 DOY;   13/09/03
SC_RA:           79.55 [deg] (J2000)
SC_DEC:          -7.23 [deg] (J2000)
SUN_POSTN:      162.21d {+10h 48m 52s}   +7.54d {+07d 32' 32"}
SUN_DIST:        80.01 [deg]   Sun_angle= 5.3 [hr] (West of Sun)
MOON_POSTN:     134.00d {+08h 56m 00s}  +12.07d {+12d 03' 58"}
MOON_DIST:       52.72 [deg]
GAL_COORDS:     203.26,-18.42 [deg] galactic lon,lat of the burst
ECL_COORDS:      81.43,-23.33 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Time_Scale=40.0000 and Time_Error=40.0000.  
COMMENTS:       refined_coordinates_after_offline_analysis  
COMMENTS:           
COMMENTS:        NOTE: This INTEGRAL event is temporally(34.0<100sec) coincident with the FERMI_GBM event (trignum=399862055).

GCN Circular #15169
S.Mereghetti (IASF-Milano), D.Gotz (CEA, Saclay), C.Ferrigno, E.Bozzo, S.Toscano (ISDC, Versoix), and J.Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report:
a gamma ray burst lasting about 70 s has been detected by IBAS in the IBIS/ISGRI data at 00:47:20 UT of September 3.
Its refined coordinates (J2000) are:
```
  R.A.: 82.1334 deg
  DEC.: -0.1252 deg
```
with an uncertainty of 1.5 arcmin (90% c.l.).
The burst had a FRED profile and a fluence of about 10^-6 erg/cmq (20-200 keV).
A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html
GCN Circular #15170
V. Sudilovsky, D. A. Kann, and J. Greiner (all MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 130903A (INTEGRAL trigger 6930; Mereghetti et al. 2013, GCN #15169) simultaneously in g'r'i'z'JHK 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 07:07 UT on 03 Sep. 2013, 6.3 hours after the GRB trigger, as soon as the GRB field became visible. They were performed at an average seeing of 1".5 and at an average airmass of 1.7.
Based on an image with an exposure time of 25 min in g'r'i'z' and 20 min in JHK, centered 7.37 hours after the GRB, we do not detect any uncatalogued sources within the 90 arcsec INTEGRAL error circle in comparison to the SDSS and 2MASS catalogs.
GCN Circular #15171
A. Volnova (IKI), V. Nevskiy (ISON), I. Molotov (KIAM), A. Pozanenko (IKI), report on behalf of larger collaboration:
We observed the field of GRB 130903A (INTEGRAL trigger 6930; Mereghetti et al. 2013, GCN 15169) with SANTEL-400AN (0.4-m f/3) telescope of ISON-Kislovodsk observatory.Observations started on Sep. 09 (UT) 01:11:40, i.e. 34 minutes after burst triger. We obtained several unfiltered images of 100 s exposure. We do not detect any source within 1.5 arcmin of error circle localization (Mereghetti et al. 2013, GCN 15169) . Photometry of combined image is following
```
T_start,                     T0+,       Exp.,   Filter,  UL (3 sigma)
(UT)                          mid (d)    (s)

01:11:40T01:11:40      0.02363  1000    none     >19.6
```
and based on SDSS stars, R (gri -> R transformations by Lupton 2005):
```
#   SDSS                      R        Err_R
1  J052835.34-000624.7 15.543 0.013
2  J052817.12-000749.0 14.650 0.012
3  J052841.64-000642.3 14.233 0.013
```
Within error circle (Mereghetti et al. 2013, GCN 15169) we note a presence of probable bright galaxy J052830.20-000723.9 r=19.706 (however marked in SDSS-DR9 as point like object).
GCN Circular #15173
Dirk Grupe (PSU) and Stephen Holland (STSCI) report on behalf of the Swift team:
We have analysed 3.2 ks of XRT data for the INTEGRAL-detected burst: GRB 130903A, from 39.6 ks to 46.4 ks after the INTEGRAL trigger. The data are entirely in Photon Counting (PC) mode. An X-ray source is detected within the INTEGRAL error circle (Mereghetti et al., GCN circ. 15169). Using 1789 s of PC mode data and 1 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 82.13013, -0.12667 which is equivalent to:
```
RA (J2000): 05h 28m 31.23s
Dec(J2000): -00d 07' 36.0"
```
with an uncertainty of 4.3 arcsec (radius, 90% confidence). This position is 12 arcsec from the INTEGRAL position. Currently the source has a 0.3-10 keV count rate in the Swift XRT of (4.9+4.9-3.0)e-3 counts/s. 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/00020294.
The Swift UVOT observed the field of GRB 130903A in V and U for 2462 and 780s, respectively. No optical counterpart was found. The 3-sigma upper limits at the position of the X-ray source are 20.6 in V and 20.4 in U.
This circular is an official product of the Swift team.
GCN Circular #15175
Shaolin Xiong (UAH) and Charles Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 00:47:32.37 UT on 03 September 2013, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 130903A (trigger 399862055 / 130903033), which was also detected by the INTEGRAL (Mereghetti et al., GCN 15169) and Swift/XRT (Grupe et al., GCN 15173). The GBM on-ground location is consistent with the INTEGRAL and Swift position. The angle from the Fermi LAT boresight is 33 degrees.
The GBM light curve consists of multiple pulses with a duration (T90) of about 69 +/- 7 s (50-300 keV). The time-averaged spectrum from T0-2 s to T0+68 s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -0.70 +/- 0.27 and the cutoff energy, parameterized as Epeak, is 41 +/- 3 keV.
The event fluence (10-1000 keV) in this time interval is (2.0 +/- 0.1)E-6 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.22 s in the 10-1000 keV band is 1.3 +/- 0.2 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #15176
E. Gorbovskoy, V. Lipunov, D. Denisenko, V. Kornilov, A. Kuznetsov, D. Kuvshinov, 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
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)
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Kislovodsk was pointed to the GRB130903A 240 sec after notice time and 244 sec after GRB time at 2013-09-03 00:51:36 UT in two polarizations. Some delay was due to weather condition. On our first (40s exposure) set we haven`t found optical transient within INTEGRAL error-box (S.Mereghetti et. al. GCN-15169 ). The 5-sigma upper limit has been about 15.0 mag in each of polarization.
On best coadd image (with use of the first 12 sets on 6 in each of polyarization) with total exposition 900 sec and middle time 504 after GRB time upper limit is 17.5 mag.
More detailed information in the following table:
```
   T_start  T_finish  T_mid     t_mid-t_trig  Exptime   Filter Limit  Coadd
---------------------------------------------------------------------------
00:51:36  00:52:16  00:51:36     264 s        40 s       P|   15.0     no
00:51:36  00:52:16  00:51:36     264 s        40 s       P-   15.0     no
00:51:36  00:52:16  00:51:36     264 s        80 s    P| + P- 15.5      2
00:51:36  01:00:16  00:55:56     504 s       450 s       P|   17.0      6
00:51:36  01:00:16  00:55:56     504 s       450 s       P-   17.0      6
00:51:36  01:00:16  00:55:56     504 s       900 s    P| + P- 17.5     12
```
P- and P| is a RA and DEC orientated polaroids.
The message may be cited.
GCN Circular #15177
M. Tanga, V. Sudilovsky, D. A. Kann, and J. Greiner (all MPE Garching) report on behalf of the GROND team:
We re-observed (Sudilovsky et al., GCN #15170) the field of GRB 130903A (Mereghetti et al. 2013, GCN #15169) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPG/ESO telescope at La Silla Observatory (Chile).
Observations are centered at 09:19 UT on 04 Sep 2013, 35.53 hours after the GRB trigger, with a total exposure time of 50 min in g'r'i'z' and 40 min in JHK. They were performed at an average seeing of 1".1 and an average airmass of 1.3.
In the XRT error circle given by Grupe & Holland (GCN #15173), we detect a source in our first epoch observations (Sudilovsky et al., GCN #15170) at coordinates
```
RA (J2000) = 05:28:31.33
Dec. (J2000) = -00:07:38.4
```
with an error of 0".3 arcseconds.
For the first epoch, we derive preliminary magnitudes (AB system) of:
```
g' = 22.4 +/- 0.1,
r' = 22.2 +/- 0.1,
i' = 22.0 +/- 0.1,
z' = 21.7 +/- 0.1,
J > 21.6,
H > 20.8, and
K > 20.1.
```
The source is still detected in g'r'i'z' in the second epoch, but is seen to have faded by 1 mag in the r' band. We therefore conclude that this is the afterglow of GRB 130903A.
Magnitudes were obtained against the SDSS catalog in g'r'i'z' and against the 2MASS catalog in JHK. They have not been corrected for the expected Galactic extinction of E(B-V) = 0.14 mag in the direction of the burst (Schlegel et al. 1998).
GCN Circular #15181
S. T. Holland (STScI) and Dirk Grupe (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began observations of the field of GRB 130903A starting 44.1 ks after the INTEGRAL/IBAS trigger (Mereghetti et al. 2013, GCNC 15169). We do not detect any new source consistent with the GROND afterglow position (Tanga et al. 2013, GCNC 15177) in any of the UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the summed exposures are presented below.
```
---------------------------------------------------
Filter       TSTART      TSTOP    Exposure      Mag
---------------------------------------------------
    v        44,128     51,114        2461    >21.2
    u        45,378     51,795        1442    >21.3
---------------------------------------------------
```
The quoted upper limits have not been corrected for the expected extinction due to the Galactic reddening along the line of sight to this burst of E(B-V) = 0.12 mag (Schlafly et al. 2011, ApJS, 737, 103).
GCN Circular #15231
Dirk Grupe (Swift MOC/PSU) report on behalf of the Swift XRT team:
We report on two additional Swift XRT observations of the INTEGRAL-discovered burst GRB 130903A (Mereghetti et al., GCN circ. 15169). As reported in Grupe & Holland (GCN circ. 15173), we found an X-ray source at a level of 5e-3 counts/s within the INTEGRAL error circle. Swift obtained a second observation on September 06 for 5.0 ks. The source reported in Grupe & Holland was still present but at a significantly lower level at (1.1+0.5-0.4)e-3 counts/s suggesting a rather slow decay slope during the 'normal' X-ray afterglow phase (e.g. see Grupe et al. 2013, arXiv:1305:3236). However, a decay by a factor of 5 is still consistent with a background AGN (e.g. Grupe et al. 2010, AJ 187, 64). Therefore we performed a third observation which was executed on September 16 for a total of 4.6 ks. In this new observation the source seems to be gone. The 3-sigma upper limit at the position of the previously detected X-ray source is at a level of 1.25e-3 counts/s. We can conclude that the X-ray source reported in Grupe & Holland (GCN circ. 15173) is most-likely the X-ray afterglow of GRB 130903A.
This circular is an official product of the Swift XRT team.
GCN Circular #15241
A. Volnova (IKI), V. Nevskiy (ISON), I. Molotov (KIAM), Yu. Krugly(IAKhNU), I. Slyusarev (IA KhNU), A. Pozanenko (IKI) report on behalf of larger collaboration:
After the refined analysis of the ISON-Kislovodsk observations (Volnova et al., GCN 15171) of GRB 130903A field (Mereghetti et al., GCN 15169) in the coordinates of OT reported by Tanga et al. (GCN 15177) we found a faint source with a R magnitude 20.40 =B1 0.3. Photometry is based on the stars reported below.
We also observed the field of the field with AZT-8 (0.7m) telescope of Institute of Astronomy, Kharkiv National University starting on Sep. 03 (UT) 01:38:52. We took 11 frames with exposures of 120 seconds in R filter. On the stacked image within 1.5 arcmin of error circle localization (Mereghetti et al., GCN 15169) we do not detect any source.
Photometry of combined image is the following
```
T_start, T0+,    Exp.,  Filter, UL (3 sigma)
(UT) mid (d)     (s)

01:38:52 0.03579 11*120 R       >20.0
```
and based on SDSS stars, R (gri -> R transformations by Lupton 2005):
```
# SDSS R Err_R
1 J052835.34-000624.7 15.543 0.013
2 J052817.12-000749.0 14.650 0.012
3 J052841.64-000642.3 14.233 0.013
```

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Jochen Greiner, last update: 21-Sep-2013 [Disclaimer]