Gamma-ray Burst 120709A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 09 Jul 12 21:12:04 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      45
TRIGGER_NUM:     363561103
GRB_RA:          338.450d {+22h 33m 48s} (J2000),
                 338.651d {+22h 34m 36s} (current),
                 337.644d {+22h 30m 34s} (1950)
GRB_DEC:         -57.767d {-57d 45' 59"} (J2000),
                 -57.702d {-57d 42' 05"} (current),
                 -58.025d {-58d 01' 28"} (1950)
GRB_ERROR:       6.02 [deg radius, statistical plus systematic]
GRB_INTEN:       593 [cnts/sec]
DATA_SIGNIF:     29.60 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        16117 TJD;   191 DOY;   12/07/09
GRB_TIME:        76300.37 SOD {21:11:40.37} UT
GRB_PHI:         200.00 [deg]
GRB_THETA:        15.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.41
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   4%  Generic Transient
DETECTORS:       0,0,0, 0,0,0, 1,0,0, 1,0,0, 0,0,
SUN_POSTN:       109.54d {+07h 18m 10s}  +22.22d {+22d 13' 19"}
SUN_DIST:        130.05 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:        2.59d {+00h 10m 22s}   +6.00d {+06d 00' 10"}
MOON_DIST:        66.59 [deg]
MOON_ILLUM:      62 [%]
GAL_COORDS:      331.56,-51.02 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      313.86,-44.28 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 87.22,-11.63 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 09 Jul 12 21:12:21 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      69
TRIGGER_NUM:     363561103
GRB_RA:          319.800d {+21h 19m 12s} (J2000),
                 320.072d {+21h 20m 17s} (current),
                 318.706d {+21h 14m 49s} (1950)
GRB_DEC:         -68.050d {-68d 02' 59"} (J2000),
                 -67.997d {-67d 59' 47"} (current),
                 -68.261d {-68d 15' 38"} (1950)
GRB_ERROR:       4.95 [deg radius, statistical plus systematic]
GRB_INTEN:       561 [cnts/sec]
DATA_SIGNIF:     43.40 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        16117 TJD;   191 DOY;   12/07/09
GRB_TIME:        76300.37 SOD {21:11:40.37} UT
GRB_PHI:         228.00 [deg]
GRB_THETA:        25.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      0.62
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   3%  Generic Transient
DETECTORS:       0,0,0, 0,0,0, 1,0,0, 1,0,0, 0,0,
SUN_POSTN:       109.54d {+07h 18m 10s}  +22.22d {+22d 13' 19"}
SUN_DIST:        130.50 [deg]   Sun_angle= 10.0 [hr] (West of Sun)
MOON_POSTN:        2.59d {+00h 10m 22s}   +6.00d {+06d 00' 13"}
MOON_DIST:        79.77 [deg]
MOON_ILLUM:      62 [%]
GAL_COORDS:      325.38,-38.53 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      295.81,-49.03 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 87.22,-11.63 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 09 Jul 12 21:14:48 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      58
TRIGGER_NUM:     363561103
GRB_RA:          332.240d {+22h 08m 58s} (J2000),
                 332.441d {+22h 09m 46s} (current),
                 331.436d {+22h 05m 45s} (1950)
GRB_DEC:         -51.150d {-51d 08' 59"} (J2000),
                 -51.088d {-51d 05' 17"} (current),
                 -51.395d {-51d 23' 43"} (1950)
GRB_ERROR:       6.69 [deg radius, statistical only]
DATA_SIGNIF:     34.80 [sigma]
DATA_INTERVAL:   1.024 [sec]
GRB_DATE:        16117 TJD;   191 DOY;   12/07/09
GRB_TIME:        76300.37 SOD {21:11:40.37} UT
GRB_PHI:         181.00 [deg]
GRB_THETA:        20.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4143 (Gnd S/W Version number)
SUN_POSTN:       109.54d {+07h 18m 10s}  +22.22d {+22d 13' 18"}
SUN_DIST:        136.07 [deg]   Sun_angle= 9.1 [hr] (West of Sun)
MOON_POSTN:        2.61d {+00h 10m 27s}   +6.01d {+06d 00' 40"}
MOON_DIST:        62.71 [deg]
MOON_ILLUM:      62 [%]
GAL_COORDS:      343.56,-51.16 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      313.85,-36.75 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the INTEGRAL_SPIACS event (trignum=6597).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 09 Jul 12 21:15:02 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      68
TRIGGER_NUM:     363561103
GRB_RA:          327.800d {+21h 51m 12s} (J2000),
                 328.011d {+21h 52m 03s} (current),
                 326.954d {+21h 47m 49s} (1950)
GRB_DEC:         -53.750d {-53d 45' 00"} (J2000),
                 -53.691d {-53d 41' 26"} (current),
                 -53.984d {-53d 59' 03"} (1950)
GRB_ERROR:       2.49 [deg radius, statistical only]
DATA_SIGNIF:     38.40 [sigma]
DATA_INTERVAL:   1.024 [sec]
GRB_DATE:        16117 TJD;   191 DOY;   12/07/09
GRB_TIME:        76300.37 SOD {21:11:40.37} UT
GRB_PHI:         191.00 [deg]
GRB_THETA:        22.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4143 (Gnd S/W Version number)
SUN_POSTN:       109.54d {+07h 18m 10s}  +22.22d {+22d 13' 18"}
SUN_DIST:        137.22 [deg]   Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN:        2.62d {+00h 10m 28s}   +6.01d {+06d 00' 43"}
MOON_DIST:        66.40 [deg]
MOON_ILLUM:      62 [%]
GAL_COORDS:      341.37,-47.69 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      309.37,-37.92 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the INTEGRAL_SPIACS event (trignum=6597).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 09 Jul 12 21:15:07 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      71
TRIGGER_NUM:     363561103
GRB_RA:          326.930d {+21h 47m 43s} (J2000),
                 327.140d {+21h 48m 33s} (current),
                 326.090d {+21h 44m 22s} (1950)
GRB_DEC:         -52.330d {-52d 19' 47"} (J2000),
                 -52.272d {-52d 16' 16"} (current),
                 -52.562d {-52d 33' 43"} (1950)
GRB_ERROR:       2.65 [deg radius, statistical only]
DATA_SIGNIF:     47.80 [sigma]
DATA_INTERVAL:   2.048 [sec]
GRB_DATE:        16117 TJD;   191 DOY;   12/07/09
GRB_TIME:        76300.37 SOD {21:11:40.37} UT
GRB_PHI:         188.00 [deg]
GRB_THETA:        23.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4143 (Gnd S/W Version number)
SUN_POSTN:       109.54d {+07h 18m 10s}  +22.22d {+22d 13' 18"}
SUN_DIST:        138.41 [deg]   Sun_angle= 9.5 [hr] (West of Sun)
MOON_POSTN:        2.62d {+00h 10m 28s}   +6.01d {+06d 00' 44"}
MOON_DIST:        65.62 [deg]
MOON_ILLUM:      62 [%]
GAL_COORDS:      343.62,-47.67 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      309.52,-36.41 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        Bright hard burst in the GBM.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the INTEGRAL_SPIACS event (trignum=6597).

GCN Circular #13423
Daniel Kocevski (Stanford Univ.), Giacomo Vianello (CIFS/SLAC), and James Chiang (KIPAC/SLAC) report on behalf of the Fermi LAT Team:
Fermi-LAT has detected high energy emission from the long, hard and bright GRB 120709A in ground analysis. The GRB was triggered on by the GBM on July 9th, 2012 at 21:11:41 UTC (trigger 363561103).
The best GBM position was ~22 deg off-axis for the duration of the prompt emission (~35 seconds), and remained within the Fermi/LAT nominal field of view for an additional ~650 seconds.
Using a non-standard data selection most sensitive in the tens-of-MeV energy range and with a broader acceptance, we significantly detected the burst between ~T0 and ~T0+5 s. The significance of the excess corresponds to ~7 sigma. The light curve also shows a secondary peaks at ~11s of lesser significance, but coincident with the second of three peaks seen in the GBM light curve.
A preliminary maximum-likelihood analysis of the E>75MeV P7SOURCE_V6 LAT data generated during the interval T0, T0+100s revealed a significant transient source, with a spectrum well described by a power law of index -2.0 +/- 0.3 (68% C.L. statistical only). Integrating over a duration covering T0 to T0+200s, we obtained the best LAT on-ground localization of:
```
RA(J2000) = 318.41 deg
Dec(J2000) = -50.03 deg
```
with an error radius of 0.35 deg (90% containment, statistical error only), which is 6.3 deg from the best GBM localization.
The zenith angle for this source was ~42.3 deg at the time of the trigger, thus very far from the Earth limb.
A Swift/ToO request has been submitted.
The Fermi-LAT point of contact for this burst is Daniel Kocevski (kocevski@stanford.edu)
GCN Circular #13426
J. Elliott, J. Greiner (both MPE Garching), A. Nicuesa Guelbenzu, S. Schmidl, S. Klose (all TLS Tautenburg) report on behalf of the GROND team:
We observed the field of GRB 120709A (Kocevski et al., GCN #13423) with the Wide-Field Imager (WFI; 33 arcmin field-of-view) at the 2.2 m MPG/ESO telescope at La Silla Observatory (Chile). In order to cover the 0.35 deg radius error circle, a mosaic of 2*2 pointings was performed. The sequence of exposures started at 07:42 UT, 10.5 hrs after the GRB, with 10 min exposure per tile. The observations were performed at an average airmass of 1.13, mean seeing of 1 arcsec, and a Moon distance of 80 deg.
We compared our R-band images with the DSS2-R plates, but find no new object brighter than R~19 mag within the 0.35 deg radius error circle.
GCN Circular #13427
Weikang Zheng and Carl Akerlof, report on behalf of the ROTSE collaboration:
We analyzed Fermi/LAT data of GRB 120709A (Kocevski et al., GCN 13423) as a follow-up of routine search in GBM trigger catalogs in our LAT data processing pipeline using the matched filter technique (Akerlof et al. 2010, ApJ, 725, L15; 2011 ApJ, 726, 22; 2012, arXiv:1205.3066; Zheng et al. 2012, ApJ 745,72; 2012, arXiv:1203.5113). We use a standard data selection method (with Energy range of 100 MeV < E < 300 GeV). About 10 photons associated with GRB are detected above 100 MeV in 47.5s duration, with the highest energy of ~3.07 GeV at 2.04s after the burst. The GRB location estimated by the matched filter technique is RA = 320.23, Dec = -51.13 with uncertainty ~0.5 degree, consistent with the location given in GCN 13423.
The photon information can be found in the following link including the skymap: http://www.rotse.net/LAT/GBMTriggers/363561103/
GCN Circular #13428
Dirk Grupe and Craig Swenson (PSU) report on behalf of the Swift-XRT team:
We have analysed 4.0 ks of XRT data for the Fermi/LAT-detected burst: GRB 120709A (Kocevski et al. GCN Circ. 13423), from 60.2 ks to 67.4 ks after the Fermi/LAT trigger. The data are entirely in Photon Counting (PC) mode. An uncatalogues X-ray source is detected within the Fermi/LAT error circle. Using 1389 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 = 318.17277, -49.97297 which is equivalent to:
```
RA (J2000): 21h 12m 41.47s
Dec(J2000): -49d 58' 22.7"
```
with an uncertainty of 3.5 arcsec (radius, 90% confidence). This position is 11.25 arcmin from the Fermi/LAT position. The source has a mean count rate of 8.8e-03 ct/sec; we cannot determine at the present time whether it is fading.
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.7 (+0.7, -0.6). The best-fitting absorption column is consistent with the Galactic value of 2.2 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 2.3 x 10^-11 (2.7 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     0 (+7.5, -0) x 10^20 cm^-2
Galactic foreground: 2.2 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     2.7 (+0.7, -0.6)
```
Note that the XRT only covered the center of the FERMI/LAT error circle (about 40%) given in Kocevski et al. (GCN Circ. 12423). There are two additional X-ray sources in the XRT image which are known sources.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020222.
This circular is an official product of the Swift-XRT team.
GCN Circular #13429
Sylvain Guiriec (GSFC), Valerie Connaughton (UAH) and Michael Briggs (UAH) report on behalf of the Fermi GBM Team:
"At 21:11:40.37 UT on 09 July 2012, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 120709A (trigger 120709883 / 120709.883).
The on-ground calculated location, using the GBM trigger data, is RA = 320.02, DEC = -47.87 (J2000 degrees, equivalent to 21h20m04, -47d52'12), with an uncertainty of 1.70 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 22 degrees. The burst was also seen by the LAT (Kocevski et al., GCN 13423)
The GBM light curve consists of 3 intense peaks with a duration (T90) of about 30 s (50-300 keV). The time-averaged spectrum from T0 s to T0+41s is adequately fit by a power law function with an exponential high-energy cutoff. The power law index is -1.22 +/- 0.03 and the cutoff energy, parameterized as Epeak, is 449 +/- 55 keV
The event fluence (10-1000 keV) in this time interval is (1.43 +/- 0.04)E-5 erg/cm^2. The 1-sec peak photon flux measured starting from T0+11.65 s in the 10-1000 keV band is 11.4897 +/- 0.2869 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #13440
S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report:
The long GRB 120709A (GBM trigger 120709883: Guiriec et al., GCN 13429; Fermi/LAT detection: Kocevski et al., GCN 13423) triggered Konus-Wind at T0=76303.609s UT (21:11:43.609)
The light curve shows multiple pulses grouped to three main episodes. A total duration of the burst is ~25 s.
The emission is seen up to ~7 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB120709_T76303/
As observed by Konus-Wind the burst had a fluence of 1.8(-0.9,+1.0)x10-5 erg/cm2, and a 64-ms peak flux, measured from T0+11.968 s, of 6.4(-1.6,+2.5)x10-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst (measured from T0 to T0+24.832 s) is well fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model, for which: alpha = -0.86 (-0.25, +0.31), and Ep = 414(-117, +233) keV, chi2 = 75.8/84 dof. This spectrum is equally well fit by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.68 (-0.45, +0.56), the high energy photon index beta = -2.0 (<-1.7), the peak energy Ep = 296(-100, +356) keV, chi2 = 75.4/83 dof.
The spectrum at the maximum count rate (measured from T0+8.848 to T0+16.640 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model, for which:
```
alpha = -0.94 (-0.23, +0.28),
and Ep = 643(-216, +470) keV,
chi2 = 81.6/84 dof.
```
All the quoted results are preliminary. All the quoted errors are at the 90% confidence level.
GCN Circular #13447
F. E. Marshall (NASA/GSFC) and C. A. Swenson (PSU) report on behalf of the Swift/UVOT team:
Swift/UVOT began observations of GRB 120709A (Kocevski et al. GCN Circ. 13423) 16.7 hours after the trigger. Observations covered the central 16'x16' region of the 0.35 deg. radius LAT error circle with the White, U, and V filters. No credible afterglow candidate was seen in any of the exposures.
The candidate X-ray afterglow from observations with Swift/XRT (Grupe and Swenson GCN Circ. 13428) is too near the edge of the UVOT images to do accurate photometry except for the 568-second white exposure starting 66.8 ks after the trigger and the 802-second U exposure starting 66.0 ks after the trigger. The catalogued optical source at the edge of the XRT error circle is clearly detected with UVOT, but there is no indication of any other source consistent with the XRT position. Preliminary magnitudes for the catalogued source and 3-sigma upper limits for positions well removed from the catalogued source using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) are given below.
```
Filter   T_Start    Exposure   Source Mag   Upper Limit
           (ks)        (s)
white      66.8       568      19.3 +/- 0.1   21.8
u          66.0       802      19.0 +/- 0.1   21.1
```
GCN Circular #13462
K. Hurley and J. Goldsten, on behalf of the MESSENGER GRNS GRB team,
S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team,
V. Connaughton, M. Briggs, and C. Meegan, on behalf of the Fermi GBM team, and
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, report:
GRB 120709A has been observed by Fermi GBM and LAT (GCN 13423, 13427, 13429), INTEGRAL (SPI-ACS), Konus-Wind (GCN 13440), and MESSENGER (GRNS), so far, at about 76300 s UT (21:11:40). A Swift XRT observation of part of the LAT error circle in GCN 13423 revealed an uncataloged X-ray source at RA, Dec = 318.17277, -49.97297 (GCN 13428). We have triangulated this burst to a preliminary, 3 sigma error box whose coordinates are:
```
    RA(2000)                         DEC(2000)
 21 h 15 m 22.14 s=318.842 o   -50 o 17 '  56.07 " =-50.290 o (CENTER)
 21 h 20 m 51.20 s=320.213 o   -50 o 16 '  14.33 " =-50.271 o (CORNER)
 21 h 09 m 08.08 s=317.284 o   -50 o 32 '  41.99 " =-50.545 o (CORNER)
 21 h 21 m 34.21 s=320.393 o   -50 o 00 '  17.46 " =-50.005 o (CORNER)
 21 h 09 m 55.60 s=317.482 o   -50 o 17 '  28.57 " =-50.291 o (CORNER)
```
The error box area is 0.46 sq. deg., and its maximum and minimum dimensions are ~ 1.9 and 0.12 degrees, respectively. This box may be improved. As the XRT source lies outside the IPN error box, at least 0.26 degrees from its closest side, it is veryy unlikely to be associated with the GRB. A map has been posted at http://ssl.berkeley.edu/ipn3/120709. On this map, "LAT1" is from GCN 13423, and "LAT2" is from GCN 13427.
GCN Circular #13509
Dirk Grupe and Craig Swenson (PSU) report on behalf of the Swift-XRT team:
Swift re-observed the field of the X-ray afterglow counterpart candidate of GRB 120709A (Kocevski et al. GCN Circ. 13423) on 2012 July 20 for 4.8 ks. In an initial observation on July 10 Swift found an uncatalogued X-ray source within the FERMI/LAT error circle (Grupe & Swenson, GCN Circ. 13428). In the new Swift observation this source is still detected at a level of (5.1+/-1.1)e-3 counts/s. This is a factor of roughly 2 lower than we had reported previously in GCN Circular #13428 for this source. Assuming a normal decay slope of an X-ray afterglow we would not expected to detect a source so late after the burst. We conclude that the X-ray source reported in GCN circular 13428 is not the X-ray afterglow of GRB 120709A. Note that this result confirms the findings by Hurley et al. (GCN Circ 13462) from IPN triangulations that the X-ray source reported by Grupe & Swenson lies significantly outside the IPN error box of GRB 120709A.

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Jochen Greiner, last update: 23-Jul-2012 [Disclaimer]