- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Fri 08 Nov 13 20:42:20 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 46
TRIGGER_NUM: 405636118
GRB_RA: 159.150d {+10h 36m 36s} (J2000),
159.334d {+10h 37m 20s} (current),
158.484d {+10h 33m 56s} (1950)
GRB_DEC: +14.267d {+14d 16' 00"} (J2000),
+14.195d {+14d 11' 40"} (current),
+14.526d {+14d 31' 35"} (1950)
GRB_ERROR: 4.13 [deg radius, statistical plus systematic]
GRB_INTEN: 1164 [cnts/sec]
DATA_SIGNIF: 59.10 [sigma]
INTEG_TIME: 1.024 [sec]
GRB_DATE: 16604 TJD; 312 DOY; 13/11/08
GRB_TIME: 74515.76 SOD {20:41:55.76} UT
GRB_PHI: 270.00 [deg]
GRB_THETA: 20.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO: 0.49
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 95% GRB
2nd_MOST_LIKELY: 4% Generic Transient
DETECTORS: 1,0,0, 1,1,0, 1,0,0, 0,0,0, 0,0,
SUN_POSTN: 224.14d {+14h 56m 33s} -16.80d {-16d 47' 56"}
SUN_DIST: 71.08 [deg] Sun_angle= 4.3 [hr] (West of Sun)
MOON_POSTN: 299.28d {+19h 57m 08s} -15.43d {-15d 25' 35"}
MOON_DIST: 141.32 [deg]
MOON_ILLUM: 34 [%]
GAL_COORDS: 228.35, 56.09 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 155.41, 5.10 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 152.47,-11.70 [deg].
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Fri 08 Nov 13 20:42:33 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 59
TRIGGER_NUM: 405636118
GRB_RA: 159.500d {+10h 38m 00s} (J2000),
159.685d {+10h 38m 44s} (current),
158.833d {+10h 35m 20s} (1950)
GRB_DEC: +14.883d {+14d 52' 60"} (J2000),
+14.811d {+14d 48' 40"} (current),
+15.144d {+15d 08' 37"} (1950)
GRB_ERROR: 4.42 [deg radius, statistical plus systematic]
GRB_INTEN: 868 [cnts/sec]
DATA_SIGNIF: 87.70 [sigma]
INTEG_TIME: 4.096 [sec]
GRB_DATE: 16604 TJD; 312 DOY; 13/11/08
GRB_TIME: 74515.76 SOD {20:41:55.76} UT
GRB_PHI: 270.00 [deg]
GRB_THETA: 20.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO: 0.51
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 95% GRB
2nd_MOST_LIKELY: 4% Generic Transient
DETECTORS: 1,0,0, 1,1,0, 1,0,0, 0,0,0, 0,0,
SUN_POSTN: 224.14d {+14h 56m 33s} -16.80d {-16d 47' 56"}
SUN_DIST: 71.02 [deg] Sun_angle= 4.3 [hr] (West of Sun)
MOON_POSTN: 299.29d {+19h 57m 09s} -15.43d {-15d 25' 33"}
MOON_DIST: 141.05 [deg]
MOON_ILLUM: 34 [%]
GAL_COORDS: 227.64, 56.67 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 155.49, 5.80 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 152.47,-11.70 [deg].
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Fri 08 Nov 13 20:42:26 UT
NOTICE_TYPE: Fermi-LAT Update Position
RECORD_NUM: 2
TRIGGER_NUM: 405636118
GRB_RA: 156.383d {+10h 25m 32s} (J2000),
156.567d {+10h 26m 16s} (current),
155.720d {+10h 22m 53s} (1950)
GRB_DEC: +11.067d {+11d 03' 60"} (J2000),
+10.996d {+10d 59' 45"} (current),
+11.321d {+11d 19' 16"} (1950)
GRB_ERROR: 30.00 [arcmin radius, 100% containment]
GRB_INTEN_TOT: 30 [cnts]
GRB_INTEN1: 68 [cnts] (0-100 MeV)
GRB_INTEN2: 33 [cnts] (0.1-1 GeV)
GRB_INTEN3: 9 [cnts] ( 1-10 GeV)
GRB_INTEN4: 7 [cnts] (10-up GeV)
INTEG_DUR: 2.233 [sec]
FIRST_PHOTON: 74515.95 SOD {20:41:55.95} UT
LAST_PHOTON: 74518.18 SOD {20:41:58.18} UT
GRB_DATE: 16604 TJD; 312 DOY; 13/11/08
GRB_TIME: 74515.76 SOD {20:41:55.76} UT
GRB_PHI: 268.28 [deg]
GRB_THETA: 24.43 [deg]
SOLN_STATUS: 0x3
BURST_ID: 0x50000
TEMP_TEST_STAT: 74.75 (log(prob), time domain)
IMAGE_TEST_STAT: 289.25 (log(prob), image domain)
LOC_QUALITY: 0.9998
SUN_POSTN: 224.14d {+14h 56m 33s} -16.80d {-16d 47' 56"}
SUN_DIST: 72.34 [deg] Sun_angle= 4.5 [hr] (West of Sun)
MOON_POSTN: 299.29d {+19h 57m 08s} -15.43d {-15d 25' 34"}
MOON_DIST: 143.48 [deg]
MOON_ILLUM: 34 [%]
GAL_COORDS: 230.88, 52.17 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 154.08, 1.13 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-LAT Coordinates.
COMMENTS: The starting/seed location came from GBM.
COMMENTS: An energy cut was applied to the gammas used for the localization.
COMMENTS: Galaxy IC612 (of total mag=15.00 and dia=0.30 arcmin) is inside the LAT position error circle.
COMMENTS: There is a 2e5% probability that an NGC galaxy would happen by chance coincidence.
- GCN NOTICE
TITLE: GCN/INTEGRAL NOTICE
NOTICE_DATE: Fri 08 Nov 13 20:42:56 UT
NOTICE_TYPE: INTEGRAL SPI ACS Trigger
TRIGGER_NUM: 6387, Sub_Num: 0
GRB_INTEN: 14.64 [sigma]
GRB_TIME: 74514.07 SOD {20:41:54.07} UT
GRB_DATE: 16604 TJD; 312 DOY; 13/11/08
COMMENTS: INTEGRAL SPI_ACS GRB Trigger.
COMMENTS: Time_Scale=2.0000 and Time_Error=1.0000.
COMMENTS:
COMMENTS: NOTE: This SPIACS event is temporally(1.0<100sec) coincident with the FERMI_GBM event (trignum=405636118).
COMMENTS:
COMMENTS: The SPIACS lightcurve can be found at:
COMMENTS: ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2013-11/2013-11-08T20-41-53.9983-10023-39824-0.lc
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Fri 08 Nov 13 22:09:29 UT
NOTICE_TYPE: Fermi-LAT Update Position
RECORD_NUM: 2
TRIGGER_NUM: 405636118
GRB_RA: 156.383d {+10h 25m 32s} (J2000),
156.567d {+10h 26m 16s} (current),
155.720d {+10h 22m 53s} (1950)
GRB_DEC: +11.067d {+11d 03' 60"} (J2000),
+10.996d {+10d 59' 45"} (current),
+11.321d {+11d 19' 16"} (1950)
GRB_ERROR: 30.00 [arcmin radius, 100% containment]
GRB_INTEN_TOT: 30 [cnts]
GRB_INTEN1: 68 [cnts] (0-100 MeV)
GRB_INTEN2: 33 [cnts] (0.1-1 GeV)
GRB_INTEN3: 9 [cnts] ( 1-10 GeV)
GRB_INTEN4: 7 [cnts] (10-up GeV)
INTEG_DUR: 2.233 [sec]
FIRST_PHOTON: 74515.95 SOD {20:41:55.95} UT
LAST_PHOTON: 74518.18 SOD {20:41:58.18} UT
GRB_DATE: 16604 TJD; 312 DOY; 13/11/08
GRB_TIME: 74515.76 SOD {20:41:55.76} UT
GRB_PHI: 268.28 [deg]
GRB_THETA: 24.43 [deg]
SOLN_STATUS: 0x20000003
BURST_ID: 0x50000
TEMP_TEST_STAT: 74.75 (log(prob), time domain)
IMAGE_TEST_STAT: 289.25 (log(prob), image domain)
LOC_QUALITY: 0.9998
SUN_POSTN: 224.20d {+14h 56m 48s} -16.82d {-16d 48' 59"}
SUN_DIST: 72.40 [deg] Sun_angle= 4.5 [hr] (West of Sun)
MOON_POSTN: 300.16d {+20h 00m 39s} -15.24d {-15d 14' 24"}
MOON_DIST: 144.33 [deg]
MOON_ILLUM: 35 [%]
GAL_COORDS: 230.88, 52.17 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 154.08, 1.13 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-LAT Coordinates.
COMMENTS: The starting/seed location came from GBM.
COMMENTS: An energy cut was applied to the gammas used for the localization.
COMMENTS: Galaxy IC612 (of total mag=15.00 and dia=0.30 arcmin) is inside the LAT position error circle.
COMMENTS: There is a 2e5% probability that an NGC galaxy would happen by chance coincidence.
COMMENTS:
COMMENTS: NOTE: This LAT event is temporally(1.0<100sec) coincident with the INTEGRAL_SPIACS event (trignum=6387).
- GCN Circular #15464
J. L. Racusin (NASA/GSFC), S. Zhu (NASA/GSFC/UMD), D. Kocevski (NASA/GSFC/ORAU), M. Ohno (Hiroshima),
N. Omodei (Stanford), E. Troja (NASA/GSFC/CRESST) and G. Vianello (Stanford), report on behalf of the Fermi LAT
team:
At 20:41:55.76 UTC on November 8, 2013, Fermi LAT triggered onboard on high energy emission from GRB 131108A.
The burst was also detected by GBM (trigger 131108863/405636118), and triggered an autonomous repoint of the
spacecraft. This is the first onboard trigger since 2009, indicating a potentially rare and exciting event.
The onboard location is R.A., Dec. 156.47, +9.90 (J2000) with an approximate error radius of 0.5 deg, seeded by the
GBM detected position. This was 27 deg from the LAT boresight at the time of the trigger. We anticipate providing a
refined location within the next 12-15 hours when the LAT science data for this burst is downlinked and processed.
The Fermi LAT point of contact for this burst is Masanori Ohno (ohno@hep01.hepl.hiroshima-u.ac.jp).
A Swift TOO request has been approved.
The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300
GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific
institutions across France, Italy, Japan and Sweden.
- GCN Circular #15465
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a series of observations, tiled on the sky, of the
Fermi/LAT GRB 131108A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00021
Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the Fermi/LAT event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; and 2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
- GCN Circular #15466
K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team,
S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks,
D. Svinkin, and T. Cline on behalf of the Konus-Wind 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 131108A (GCN 15464) has been observed by MESSENGER and INTEGRAL
(SPI-ACS) so far. We have triangulated it to a preliminary annulus
centered at RA(2000)=211.006 degrees, Dec(2000)=-10.955 degrees, with
radius 57.980 +/- 0.055 degrees (3 sigma). This annulus intersects the
LAT error circle, reducing its area by about a factor of 7, and forming
an error box whose area is approximately 390 sq. arcmin., and whose
corners are
RA(2000) Dec(2000)
156.363 o=10 h 25 m 27 s 9.411 o= 9 o 24 ' 40 "
156.702 o=10 h 26 m 48 s 10.345 o= 10 o 20 ' 42 "
156.477 o=10 h 25 m 54 s 9.400 o= 9 o 24 ' 00 "
156.797 o=10 h 27 m 11 s 10.283 o= 10 o 16 ' 57 "
A map has been posted at ssl.berkeley.edu/ipn3/130811A. This error box can be improved.
- GCN Circular #15467
The URL given in GCN 15466 was incorrect. The correct URL is
ssl.berkeley.edu/ipn3/131108A. I apologize for the confusion and
thank those of you who quickly pointed this out.
- GCN Circular #15468
M. C. Stroh and J. A. Kennea (PSU) report on behalf of the Swift/XRT team:
Swift-XRT has observed the error circle of the Fermi/LAT GRB 131108A (Racusin et al., GCN #15464, Evans, GCN #15465) in a series of observations tiled on the sky. In 621 s of data, beginning 3.9 ks after the Fermi/LAT trigger, we detect a bright, fading, uncatalogued X-ray source at RA, Dec = 156.50066, 9.66232 which is equivalent to:
RA (J2000.0) = 10h 26m 0.16s
Dec (J2000.0) = +09d 39' 44.4"
with an uncertainty of 3.6 arcsec (radius, 90% confidence). We note that this position lies 14.4' from the center of the Fermi/LAT
error circle (GCN #15464), consistant with that position, and inside the IPN error box (GCN #15466).
This previously uncatalogued source is significantly brighter than the RASS limit and fading, and we thus consider it the likely GRB afterglow.
The source was detected in 2 overlapping fields, with target IDs:
00020321, 00020322.
The results of the automated XRT processing of the source in these fields are available at:
http://www.swift.ac.uk/xrt_products/TILED_GRB00021/00020321
http://www.swift.ac.uk/xrt_products/TILED_GRB00021/00020322
This circular is an official product of the Swift-XRT team.
- GCN Circular #15469
J. Gorosabel (IAA-CSIC/UPV-EHU), S. Mottola (DLR), A. de Ugarte Postigo (IAA-CSIC/DARK-NBI), S. Hellmich (DLR), G. Proffe (DLR), report on behalf of a large collaboration:
We imaged the field of GRB 131108A (Racusin et al. GCNC 15464) with the 1.23m CAHA telescope. The observations were carried out in the V-band starting at 03:28:33 UT. A bright V~18.5 object not present on the DSS is detected consistent with the possible X-ray afterglow position (Stroh & Kennea, GCNC 15468). Further observations are in progress.
- GCN Circular #15470
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), C.C. Thoene (IAA-CSIC),
J. Gorosabel (IAA-CSIC), R. Sanchez-Ramirez (IAA-CSIC),
J.P.U. Fynbo (DARK/NBI), N.R. Tanvir (U. Leicester),
A. Cabrera-Lavers (ULL/IAC) and A. Garcia (ULL/IAC) report on
behalf of a larger collaboration:
We have observed the afterglow of the Fermi-LAT GRB 131108A (Racusin
et al. GCN 15464, Hurley et al. GCN 15466, Stroh et al. GCN 15468, Gorosabel
et al. GCN 15469) with the 10.4m GTC telescope at Roque de los Muchachos
Observatory (La Palma, Spain) starting at 04:50 UT (8.13 hr after the burst).
The observation consisted of 3x600 s and was performed with the R1000B
grism, that covers the range from 3700 to 7500 A at a resolution of ~1000.
Observations were performed with a poor seeing of ~2.2". The afterglow is
detected in the acquisition frame with at a magnitude of r=18.9, as compared
with the SDSS.
A preliminary reduction of the spectrum shows a strong trace and is
characterised by a strong Ly-alpha absorption as well as absorption features
which include SII, SiII, SiII*, OI, CII, SiIV, CIV and AlII at a common redshift of
z=2.40, which we identify as the redshift of the GRB.
- GCN Circular #15471
D. Xu, D. Malesani (DARK/NBI), T. Pursimo (NOT) report on behalf of a
larger collaboration:
We observed the Swift/XRT field of Fermi-detected GRB 131108A (Racusin
et al., GCN 15464; Stroh & Kennea, GCN 15468) using the 2.5m Nordic
Optical Telescope (NOT) equipped with the MOSCA camera. We obtained
SDSS ugriz frames, starting at 04:46:48 UT on 2013-11-09 (i.e., 8.081
hr after the Fermi/LAT trigger).
The optical afterglow is detected at the border of the XRT error
circle reported in Stroh & Kennea (GCN 15468) at coordinates
R.A. (J2000) = 10:26:00.48
Dec. (J2000) = +09:39:44.05
Error Radius: ~0.5 arcsec
thus being consistent with the XRT position, as reported in Gorosabel
et al. (GCN 15469). In particular, the ugriz SED shows a clear drop at
the wavelength range corresponding to the spectroscopic redshift of
z=2.40 in de Ugarte Postigo et al. (GCN 15470).
- GCN Circular #15472
G. Vianello (Stanford), N.Omodei (Stanford), J.Racusin (NASA/GSFC) and M.
Ohno (Hiroshima) report on behalf of the Fermi LAT team:
We have analyzed 1.5 ks of data for GRB 131108A which triggered onboard
Fermi/LAT (Racusin et al, GCN 15464) as well as Fermi/GBM.
We confirm the detection of the GRB in our standard analysis at the
position of the afterglow candidate (Stroh and Kennea, GCN 15468; Gorosabel
et al., GCN 15469; de Ugarte Postigo et al., GCN 15470), with a very large
significance (>> 10 sigma).
As seen by Fermi/LAT the burst is bright, but relatively soft. In this
preliminary analysis the light curve appears well correlated with the
emission at lower energy, as seen by Fermi/GBM.
More than 118 photons above 100 MeV and more than 3 photons above 1 GeV are
observed within 1500 seconds. The highest energy photon is a 1.5 GeV event
which is observed 66 seconds after the GBM trigger, which at redshift 2.4
(GCN 15470) corresponds to 5 GeV rest-frame. The time-integrated spectrum
in the same time interval can be well described by a power law with photon
index -2.66 +/- 0.12, with a mean flux of 1.0e-08 +/- 1.3e-09 erg/cm2/s
(100 MeV - 100 GeV).
Fermi-LAT pointed observations are ongoing.
The Fermi LAT point of contact for this burst is Masanori Ohno (
ohno@hep01.hepl.hiroshima-u.ac.jp).
The Fermi LAT is a pair conversion telescope designed to cover the energy
band from 20 MeV to greater than 300 GeV. It is the product of an
international collaboration between NASA and DOE in the U.S. and many
scientific institutions across France, Italy, Japan and Sweden.
- GCN Circular #15473
Klotz A., Turpin D. (IRAP-CNRS-OMP), Pelassa V. (UAH), Gendre B.,
Boer M., Siellez K., Dereli H., Bardho O. (UNS-CNRS-OCA),
Atteia J.L. (IRAP-CNRS-OMP) report:
We imaged the field of GRB 131108A detected by Fermi-LAT and Fermi-GBM
(Racusin et al., GCN 15646) with the TAROT robotic telescope (D=25cm)
located at the Calern Observatory, France.
The observations started about 22700s after the GRB trigger (3:00 UT on
2013-11-09), when the object started to be visible. The weather
conditions were poor, with only one sequence of 6 images being not cloudy.
We detect the afterglow reported by Stroh et al. (GCN 15468) and
Gorosabel et al. (GCN 15469), with a magnitude of R = 17.8 +/- 0.2.
Magnitudes were estimated with the nearby NOMAD1 stars
and are not corrected for galactic dust extinction.
This message may be cited.
- GCN Circular #15474
M. C. Stroh and J. A. Kennea (PSU) report on behalf of the Swift-XRT
team:
We have analysed 7.9 ks of XRT data for the Fermi/LAT-detected burst:
GRB 131108A, from 25.9 ks to 49.8 ks after the Fermi/LAT trigger. The
data are entirely in Photon Counting (PC) mode. An X-ray source is
detected within the Fermi/LAT error circle. Using 4560 s of PC mode
data and 6 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 = 156.50178, +9.66248 which is equivalent to:
RA (J2000): 10h 26m 00.43s
Dec(J2000): +09d 39' 44.9"
with an uncertainty of 1.6 arcsec (radius, 90% confidence). This
position is 14.4 arcmin from the center of the Fermi/LAT error circle
(GCN #15464), consistant with that position, and inside the
IPN error box (GCN #15466).
The light curve can be modelled with a power-law decay with a decay
index of alpha=1.9 (+0.7, -0.6).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.2 (+0.4, -0.3). The
best-fitting absorption column is 9.9 (+7.6, -6.5) x 10^20 cm^-2, in
excess of the Galactic value of 3.2 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 3.2 x 10^-11 (4.5 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 9.9 (+7.6, -6.5) x 10^20 cm^-2
Galactic foreground: 3.2 x 10^20 cm^-2
Excess significance: 1.7 sigma
Photon index: 2.2 (+0.4, -0.3)
If the light curve continues to decay with a power-law decay index of
1.9, the count rate at T+24 hours will be 5.2 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.7 x
10^-13 (2.4 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020326.
This circular is an official product of the Swift-XRT team.
- GCN Circular #15475
Eleonora Troja (GSFC), 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), Owen
Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM),
Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1=
iga
(UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We observed the field of the LAT GRB 131108A (Racusin, et al., GCN 15464,
Vianello et al., GCN 15472) with the Reionization and Transients Infrared
Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the
Observatorio Astron=F3mico Nacional on Sierra San Pedro M=E1rtir from 2013/11
9.41 to 2013/11 9.53 UTC (13.06 to 16.11 hours after the LAT trigger),
obtaining a total of 2.11 hours exposure in the r and i bands and 0.76
hours
exposure in the Z, Y, J, and H bands.
For a source within the enhanced XRT error circle (Stroh & Kennea, GCN
15474) , in comparison with the SDSS DR9 and 2MASS, we obtain the
following detections:
r 19.91 =B1 0.02
i 19.70 =B1 0.02
Z 19.57 =B1 0.04
Y 19.23 =B1 0.05
J 19.34 =B1 0.07
H 19.09 =B1 0.08
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. We can confirm that this source=20
fades
during our observations with a power-law decay index of approximately -2.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedr=
o
M=E1rtir.
- GCN Circular #15476
M.M. Chester and M. C. Stroh (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of the Fermi/LAT-detected
GRB 131108A 25920 s after the LAT trigger (Racusin et al., GCN Circ. 15464).
A source consistent with the XRT position (Stroh and Kennea GCN Circ. 15474)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 10:26:00.45 = 156.50187 (deg.)
Dec (J2000) = +09:39:44.1 = 9.66225 (deg.)
with an estimated uncertainty of 0.58 arc sec. (radius, 90% confidence).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 27746 28046 295 19.70 +/- 0.10
b 26833 27133 295 19.67 +/- 0.16
u 25920 26220 295 19.10 +/- 0.14
w1 31699 32599 886 20.96 +/- 0.33
m2 37465 37914 442 >20.6
w2 45446 49794 1069 >21.4
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.028 in the direction of the burst
(Schlegel et al. 1998).
- GCN Circular #15477
G. Younes (USRA/NASA-MSFC) reports on behalf of the Fermi GBM Team:
At 20:41:55.76 UT on 08 November 2013, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 131108A (trigger 405636118/131108862), which also
triggered onboard the Fermi/LAT (Racusin et al, GCN 15464). The GBM on-ground
location is consistent with the Swift/XRT location of the candidate afterglow
(M. C. Stroh and J. A. Kennea, GCN 15468).
The burst was bright enough that it also resulted in an Autonomous Repoint Request (ARR).
The GBM light curve consists of a multiple-peak structure with a duration
(T90) of about 19 s (50-300 keV). The time-averaged spectrum from
T0 to T0+21 s is adequately fit by a Band function with Epeak =
373 +/- 14 keV, alpha = -0.91 +/- 0.02, and beta = -2.6 +/- 0.1.
The event fluence (10-1000 keV) in this time interval is
(3.65 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.1 s in the 10-1000 keV band is 19.8 +/- 0.4 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog.
- GCN Circular #15478
D. A. Perley (Caltech) reports on behalf of a larger collaboration:
We observed the position of Fermi GRB 131108A (Racusin et al., GCN
15464) with the Combined Array for Research in Millimeter Astronomy at a
frequency of 93 GHz (3mm) starting at 13:26 UT on 2013-11-09, 16.7 hours
after the burst. Observations continued until 14:55 UT (midpoint t=17.5
hours.)
A source is detected at a position consistent with the location of X-ray
(Stroh & Kennea, GCN 15468) and optical (Xu et al., GCN 15471)
afterglows at a flux of approximately ~2 mJy. Follow-up observations
are planned.
We thank the CARMA staff for their support in executing these observations.
- GCN Circular #15479
A. Giuliani (INAF/IASF-Mi), F. Longo (University of Trieste and INFN Trieste),
F. Verrecchia, C. Pittori (ASDC and INAF/OAR), M. Marisaldi, F. Fuschino
(INAF/IASF-Bo), F. Lucarelli (ASDC and INAF/OAR),
E. Del Monte, F. Lazzarotto, I. Donnarumma, Y. Evangelista, M. Feroci, L.
Pacciani, P. Soffitta, E. Costa,
I. Lapshov, M. Rapisarda (INAF/IAPS Rome), G. Barbiellini, (INFN Trieste),
A. Bulgarelli, F. Gianotti, M. Trifoglio, G. Di Cocco, C. Labanti, V.
Fioretti, M. Galli (INAF/IASF-Bo),
A. Chen, S. Mereghetti, F. Perotti, P. Caraveo (INAF/IASF-Mi),
M. Cardillo, E. Striani, M. Tavani (INAF/IAPS Rome, and Univ. Roma Tor Vergata),
A. Argan, G. Piano, S. Sabatini, V. Vittorini (INAF/IAPS Rome),
G. Pucella (ENEA Frascati), A. Pellizzoni, A. Trois (INAF/OA Cagliari),
M. Pilia (ASTRON), S. Vercellone (INAF/IASF-Pa),
P. W. Cattaneo, A. Rappoldi (INFN Pavia), A. Morselli, P. Picozza (INFN Roma-2),
M. Prest, E. Vallazza (Universita` dell'Insubria),
P. Lipari, D. Zanello (INFN Roma-1), P. Giommi (ASI), and G. Valentini (ASI),
on behalf of the AGILE Team, report:
GRB 131108A (GCN 15464) transited in the field of view of AGILE
approximately between t0-20 and t0+150 sec (with t0 = 08:41:55 UT).
A preliminary analysis of the Gamma-Ray Imaging Detector (GRID) data in
temporal and spatial coincidence with the GRB shows a significant excess of
gamma-ray events above 30 MeV at the location of the event.
During the first 80 seconds after t0 the GRID instrument detected 66
photons compatible with the GRB, most of which below 100 MeV, corresponding
to a fluence of 2.56 +- 0.32 1e-5 erg / cm^2 in the energy band 30 MeV -
1 GeV.
The energy distribution of photons in the same energy band is compatible
with a power-law of index -2.35 +-0.2 .
An analysis of the AGILE/MCAL data is also in progress.
More observations of this interesting burst are strongly encouraged.
This message may be cited.
[GCN OPS NOTE(09nov13): This was delayed by ~1 hour because the submitor's
new account had to added to the Circulars list.]
- GCN Circular #15480
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin,
P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf
of the Konus-Wind team, report:
The long-duration, bright, hard-spectrum GRB 131108A
(Fermi-LAT detection: Racusin, et al., GCN 15464; Vianello, et al., GCN 1=
5472;
IPN triangulation: Hurley at al., GCN 15466;
Fermi-GBM observation: Younes, GCN 15477;
AGILE/GRID observation: Giuliani, et al., GCN 15479)
triggered Konus-Wind at T0=3D74512.947 s UT (20:41:52.947).
The light curve shows a mult-peaked structure from ~T0 to ~T0+20 s.
The emission is seen up to ~12 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB131108_T74512/
As observed by Konus-Wind, the burst
had a fluence of (4.15 =B1 0.25)x10-5 erg/cm2,
and a 64-ms peak flux, measured from T0,
of (2.10 =B1 0.15)x10-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum (measured from T0 to T0+23.04 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha =3D -1.11 =B1 0.05,
the high energy photon index beta =3D -2.72 =B1 0.06,
the peak energy Ep =3D 340 =B1 11 keV,
chi2 =3D 69.2/95 dof.
The spectrum of the brightest initial spike
(measured from T0 to T0+0.256 s)
is best fit in the 50 keV - 15 MeV range
by the cutoff power law with the following model parameters:
the photon index alpha =3D -1.21 =B1 0.11,
and the peak energy Ep =3D 1326 =B1 382 keV,
chi2 =3D 52.9/70 dof.
Assuming the redshift z=3D2.40 (de Ugarte Postigo, et al., GCN 15470;
Xu, et al., GCN 15471),
and a standard cosmology model with H_0 =3D 70 km/s/Mpc,
Omega_M =3D 0.27, and Omega_Lambda =3D 0.73,
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is (5.8 =B1 0.4)x10^53 erg,
the peak luminosity L_iso is (1.0 =B1 0.07)x10^54 erg/s,
and the rest-frame peak energy Ep,i =3D (1160 =B1 40) keV
All the quoted results are preliminary.
- GCN Circular #15482
Eleonora Troja (GSFC), 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), Owen
Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM),
Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1=
iga
(UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We observed the field of GRB 131108A (Racusin et al., GCN 15464,
Vianello et al., GCN 15472 ) with the Reionization and Transients Infrare=
d
Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the
Observatorio Astron=F3mico Nacional on Sierra San Pedro M=E1rtir from 201=
3/11
11.40 to 2013/11 11.53 UTC (61.01 to 64.03 hours after the LAT trigger),
obtaining a total of 2.04 hours exposure in the r and i bands and
0.89 hours exposure in the Z, Y, J, and H bands.
We continue to detect the previously reported source (Troja et al.,
GCN 15475). In comparison with the SDSS DR9 and 2MASS, we obtain
the following detections and upper limits (3-sigma):
r 22.4 =B1 0.12
i 22.03 =B1 0.11
Z 21.95 =B1 0.22
Y 21.6 =B1 0.3
J > 21.5
H > 21.0
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. A comparison with our earlier
observations suggests a decay index of approximately -1.6 between our
observations of 2013 Nov 9 and these observations.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro
M=E1rtir.
- GCN Circular #15484
A. Volnova (IKI), Yu. Krugly (IA KhNU), R. Inasaridze (AAO), I.
Slyusarev (IA KhNU), G. Inasaridze (AAO), V. Zhuzhunadze (AAO), I.
Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB
follow-up collaboration:
We observed the field of Swift GRB 131108A (Racusin et al., GCN 15464,
Hurley et al. GCN 15466) with AZT-8 telescope of Institute of
Astronomy, Kharkiv National University and with AS-32 telescope of
Abastumani Observatory. We obtained several images in R-filter and
also non-fileterd images. Within the enhanced XRT circle (Stroth &
Kennea, GCN 15474) we detect the optical counterpart reported by
Gorosabel et al. (GCN 15469).
The details of preliminary photometry are following:
UT start t-T0 Filter Exp. OT
(mid, days) (s)
2013-11-10T02:00:12 1.24560 R 15x300 20.92 +/- 0.12
2013-11-11T00:44:00 2.21609 None 36x120 21.20 +/- 0.11
The photometry is based the SDSS stars, R magnitude (gri -> R
transformations by Lupton 2005):
SDSS id R
J102559.54+093904.1 16.928 +/- 0.014
J102609.18+093958.8 17.999 +/- 0.021
J102610.10+093859.6 17.339 +/- 0.014
- GCN Circular #15485
A. Volnova (IKI), D. Varda (ISON), E. Sinyakov (ISON), I. Molotov
(KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up
collaboration:
We observed the field of GRB 131108A (Racusin et al., GCN 15464,
Hurley et al., GCN 15466) with ORI-25 telescope of ISON-Blagoveshensk
observatory starting Nov., 9 (UT) 16:40:45. We took several unfiltered
images with exposures of 30 seconds. In the combined images in the
enhanced XRT circle (Stroth & Kennea, GCN 15474) we do not detect the
OT reported by Gorosabel et al. (GCN 15469).
The details of the photometry are the following:
UT start t-T0 Filter Exp. OT UL (3sigma)
(mid, days) (s)
16:40:45 0.85072 None 95x30 n/d 17.1
The photometry is based on a nearby bright SDSS star, R (gri -> R
transformations by Lupton 2005):
SDSS id R
J102613.43+094109.5 13.318 +/- 0.013
- GCN Circular #15502
A. Corsi (GWU), S. B. Cenko (NASA/GSFC), and D. A. Perley (Caltech) report
on behalf of a larger collaboration:
We imaged the position of the Fermi-LAT GRB 131108A (Racusin et al., GCN
15464) with the Very Large Array in the 18.7-24.9 GHz frequency range,
starting at about 2.6 days after the burst. A provisional reduction shows
a source consistent with the location of the X-ray (Stroh and Kennea,
GCN 15468) and optical (e.g., Xu et al., GCN 15471) afterglow. At this
time, we estimate a preliminary flux of about 200 uJy at 19 GHz.
Further observations are planned.
We thank the VLA staff for their support.
- 1407.0238 from 2 Jul 14
A. Giuliani et al.: A prompt extra component in the high energy spectrum of GRB 131108A
The high-fluence GRB131108A at redshift z=2.4, was detected by the Mini-Calorimeter (MCAL, 0.35-100 MeV) and the Gamma- Ray Imaging Detector
(GRID, 30 MeV - 30 GeV) onboard the AGILE satellite. The burst emission consisted of a very bright initial peak,lasting 0.1 s, followed by a
fainter emission detected for ~25 s with the MCAL and ~80 s with the GRID. The AGILE spectra, when compared with those reported at lower
energies, indicate the presence of a prominent high-energy component with peak energy in the 10-20 MeV region. Contrary to other GRBs, this
high-energy component is present also during the initial peak, with power law photon index of about -1.6 below 10 MeV and -2.35+-0.2 above 30
MeV.
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