- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Mon 14 Oct 13 05:09:25 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 44
TRIGGER_NUM: 403420143
GRB_RA: 116.550d {+07h 46m 12s} (J2000),
116.704d {+07h 46m 49s} (current),
115.990d {+07h 43m 58s} (1950)
GRB_DEC: -18.000d {-18d 00' 00"} (J2000),
-18.034d {-18d 02' 03"} (current),
-17.877d {-17d 52' 35"} (1950)
GRB_ERROR: 3.32 [deg radius, statistical plus systematic]
GRB_INTEN: 10555 [cnts/sec]
DATA_SIGNIF: 245.70 [sigma]
INTEG_TIME: 0.256 [sec]
GRB_DATE: 16579 TJD; 287 DOY; 13/10/14
GRB_TIME: 18540.20 SOD {05:09:00.20} UT
GRB_PHI: 139.00 [deg]
GRB_THETA: 60.00 [deg]
DATA_TIME_SCALE: 0.2560 [sec]
HARD_RATIO: 0.33
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 96% GRB
2nd_MOST_LIKELY: 3% Generic Transient
DETECTORS: 0,0,0, 0,0,0, 0,1,0, 1,1,1, 0,0,
SUN_POSTN: 199.42d {+13h 17m 41s} -8.20d {-08d 12' 06"}
SUN_DIST: 80.59 [deg] Sun_angle= 5.5 [hr] (West of Sun)
MOON_POSTN: 321.48d {+21h 25m 55s} -9.70d {-09d 41' 57"}
MOON_DIST: 143.02 [deg]
MOON_ILLUM: 75 [%]
GAL_COORDS: 235.16, 3.41 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 122.88,-38.46 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 66.38,19.55 [deg].
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Mon 14 Oct 13 05:09:34 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 58
TRIGGER_NUM: 403420143
GRB_RA: 116.600d {+07h 46m 24s} (J2000),
116.754d {+07h 47m 01s} (current),
116.041d {+07h 44m 10s} (1950)
GRB_DEC: -18.067d {-18d 04' 00"} (J2000),
-18.101d {-18d 06' 03"} (current),
-17.943d {-17d 56' 35"} (1950)
GRB_ERROR: 3.27 [deg radius, statistical plus systematic]
GRB_INTEN: 18757 [cnts/sec]
DATA_SIGNIF: 1240.70 [sigma]
INTEG_TIME: 2.048 [sec]
GRB_DATE: 16579 TJD; 287 DOY; 13/10/14
GRB_TIME: 18540.20 SOD {05:09:00.20} UT
GRB_PHI: 139.00 [deg]
GRB_THETA: 60.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO: 0.36
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 96% GRB
2nd_MOST_LIKELY: 3% Generic Transient
DETECTORS: 0,0,0, 0,0,0, 0,1,0, 1,1,1, 0,0,
SUN_POSTN: 199.42d {+13h 17m 41s} -8.20d {-08d 12' 07"}
SUN_DIST: 80.54 [deg] Sun_angle= 5.5 [hr] (West of Sun)
MOON_POSTN: 321.48d {+21h 25m 55s} -9.70d {-09d 41' 56"}
MOON_DIST: 143.00 [deg]
MOON_ILLUM: 75 [%]
GAL_COORDS: 235.24, 3.41 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 122.96,-38.51 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 66.38,19.55 [deg].
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Mon 14 Oct 13 05:09:39 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 57
TRIGGER_NUM: 403420143
GRB_RA: 101.890d {+06h 47m 34s} (J2000),
102.039d {+06h 48m 09s} (current),
101.349d {+06h 45m 24s} (1950)
GRB_DEC: -20.020d {-20d 01' 11"} (J2000),
-20.036d {-20d 02' 08"} (current),
-19.964d {-19d 57' 49"} (1950)
GRB_ERROR: 1.00 [deg radius, statistical only]
DATA_SIGNIF: 1359.90 [sigma]
DATA_INTERVAL: 2.048 [sec]
GRB_DATE: 16579 TJD; 287 DOY; 13/10/14
GRB_TIME: 18540.20 SOD {05:09:00.20} UT
GRB_PHI: 147.00 [deg]
GRB_THETA: 72.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 4143 (Gnd S/W Version number)
SUN_POSTN: 199.42d {+13h 17m 41s} -8.20d {-08d 12' 07"}
SUN_DIST: 94.05 [deg] Sun_angle= 6.5 [hr] (West of Sun)
MOON_POSTN: 321.48d {+21h 25m 55s} -9.70d {-09d 41' 55"}
MOON_DIST: 131.11 [deg]
MOON_ILLUM: 75 [%]
GAL_COORDS: 230.50, -9.80 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 105.31,-42.83 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: Bright hard burst in the GBM.
COMMENTS: This Notice was ground-generated -- not flight-generated.
- GCN Circular #15332
G. Fitzpatrick (UCD) and S. Xiong (UAH) report on behalf of the Fermi GBM
Team:
At 05:09:00.20 UT on 14 October 2013, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 131014A (trigger 403420143/131014215).
High peak flux from the GRB caused GBM to issue a repoint request
that reoriented the satellite to place the GRB near the LAT boresight
for 2.5 hours, subject to Earth limb contraints.
The on-ground calculated location, using the GBM trigger
data, is RA = 101.9 , DEC = -20.0 (J2000 degrees,
equivalent to 06h 47m, -20d 0.0'), with an uncertainty
of 1.00 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 71.9 degrees.
The GBM light curve consists of a single peak
with a duration (T90) of about 3.2 s (50-300 keV).
The event fluence (10-1000 keV) in this time interval is
1.9E-4 +/- 2E-7 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.3 s in the 10-1000 keV band is 311.5 +/- 1.3 ph/s/cm^2.
The time-averaged spectrum from T0-1.0 s to T0+4.2 s is
adequately fit by a Band function with Epeak = 318 +/- 3 keV,
alpha = -0.34 +/- 0.01, and beta = -2.58 +/- 0.02
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog.
- GCN Circular #15333
R. Desiante (University of Udine and INFN Trieste), D. Kocevski(NASA/Goddard),
G. Vianello (Stanford), F.Longo, E.Bissaldi (University and INFN Trieste)
and E.Troja (NASA/GSFC/CRESST) report on behalf of the Fermi-LAT team:
At 05:09:00.20 on 2013-10-14 Fermi LAT detected high energy emission
from GRB 131014A, which was also detected by Fermi-GBM (G. Fitzpatrick
and S. Xiong, GCN 15332).
The best LAT on-ground location is found to be RA, DEC 100.5, -19.1 (J2000)
with an error radius of 0.45 deg (68% containment, statistical error only).
This was at the edge of the field of view of the LAT at the time of the
trigger (~70 deg away from the instrument axis). The burst triggered an
autonomous repoint of the spacecraft, which moved it well within the LAT
field-of-view for an additional 500s, before the source was occulted
by the Earth.
Due to the large angle at which the burst was observed during most of the
exposure, we expect a systematic error on the position of up to 0.5 deg.
This is due to the fact that the reconstruction of the direction of incoming
photons is biased toward the axis of the instrument for sources at very
large off-axis angles.
More than 7 photons above 100 MeV and 3 photons above 1 GeV are observed
within 100 seconds. The highest energy photon is a 1.8 GeV event which is
observed ~15 seconds after the GBM trigger.
A single peaked emission lasting roughly 5 seconds can be seen using the
non-standard LAT Low Energy (LLE) with a significance of ~23 sigma.
A Swift ToO request for this burst has been submitted and approved.
The Fermi LAT point of contact for this burst is
Rachele Desiante (rachele.desiante@ts.infn.it).
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 #15334
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 131014A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00019
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 #15335
J. A. Kennea (PSU) and Alex Amaral-Rogers (U Leicester) report on behalf
of the Swift/XRT team
On October 14, 2013 at 17:24 UT, Swift began a series of target of
opportunity observations to cover the region around GRB131014A
(Fitzpatrick et al., GCN #15332, Evans, GCN #15334), approximately 12.3
hours after the burst was detected by Fermi. In Swift/XRT Photon Counting
mode data we detect an uncatalogued point source at the following
location: RA/Dec(J2000) = 100.30064, -19.09711, which is equivalent to:
RA(J2000) = 06h 41m 12.2s
Dec(J2000) = -19d 05m 49.6s
with an estimated uncertainty of 4.4 arc-seconds radius (90% containment).
This position is 11.3' from the LAT position reported by Desiante et al.
(GCN #15333). The source brightness is 0.07 +/- 0.01 XRT count/s. We
cannot yet confirm whether this source is fading.
- GCN Circular #15336
D. Xu (DARK/NBI), X. Zhang, G.-J. Feng, A. Esamdin, L. Ma (XAO) report:
We observed the XRT field (Kennea et al., GCN 15335), which contains
an uncatalogued point source as the possible X-ray afterglow of GRB
131014A (Fitzpatrick et al., GCN 15332; Desiante et al., GCN 15333),
using the 1m telescope located Mt. Nanshan, Xinjiang, China. We
obtained 2x600s R-band images at a high airmass of ~2.4 and at the
mean time of 2013-10-14 22:52:52 UT (i.e., 17.73 hr after the Fermi
trigger).
A faint source is marginally detected at the North-West border of the
XRT error circle in Kennea et al. (GCN 15335) in the stacked image,
and its position is consistent with that of the object already present
in the DSS finding chart at coordinates
R.A. (J2000) = 06:41:11.950
Dec. (J2000) = -19:05:46.94
However, the seemingly extended structure of the object within the XRT
error in the DSS chart is not present in our image, which sets a
constraint of R > ~20.5 mag for any source within the XRT error
circle, calibrated with nearby USNO B1 field.
- GCN Circular #15337
S. Schulze (PUC, MCSS), D. Xu , D. Malesani, J. P. U. Fynbo (DARK/NBI), T. Kangas (NOT), H. Ghasemi, A. Takalo, C. Xavier, Y. Litus, J. Saario, T. Tuominen, J. Harmanen, and M. Khansari (Tuorla Observatory) report on behalf of a large collaboration:
We observed the field of GRB 131014A (Fitzpatrick & Xiong, GCN15332; Desiante et al., GCN 15333) with the 2.5-m Nordic Optical Telescope (NOT) equipped with ALFOSC. We obtained 6 x 300 s R-band images. The mean time of the NOT observation is October 15.221 UT, 1.01 days after the Fermi trigger.
We detect an uncatalogued source within the error circle of the possible X-ray afterglow (Kennea et al., GCN 15335) at:
R.A.(J2000) = 06:41:12.240
Dec. (J2000) = -19:05:51.49
with an uncertainty of 0.4''.
This source may be the optical afterglow of GRB 131014A, but we cannot presently assess its variability and thus confirm its nature. We measure a R1 magnitude of 23.11 +/- 0.12 mag calibrated against four USNO B1 stars (0709-0091487, 0708-0089714, 0709-0091459, 0709-0091432).
We also note the presence of a brighter source (R.A. = 06:41:12.1, Dec. = -19:05:47.6) just to the North of the XRT error circle, which is however detected in the SDSS r-band frames.
- GCN Circular #15338
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 very bright GRB 131014A
(Fermi GBM detection: Fitzpatrick & Xiong, GCN 15332;
Fermi LAT detection: Desiante et al., GCN 15333)
triggered Konus-Wind at T0=3D18541.405 s UT (05:09:01.405).
The light curve shows multiple bright, overlapped
pulses from ~T0 s to ~T0+6~s.
The emission at this phase of the event is seen up to ~12 MeV.
The burst was followed by a ~150s-long decaying tail of
a weak, soft, extended emission.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB131014_T18541/
As observed by Konus-Wind, the burst
had a fluence of (2.05 =B1 0.03)x10-4 erg/cm2,
and a 64-ms peak flux, measured from T0+1.664 s,
of (2.10 =B1 0.04)x10-4 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum (measured from T0 to T0+12.288 s)
is best fit in the 50 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha =3D -0.79 =B1 0.04,
the high energy photon index beta =3D -2.89 =B1 0.08,
the peak energy Ep =3D 346 =B1 9 keV,
chi2 =3D 118/94 dof.
The spectrum near the maximum count rate
(measured from T0+1.536 s to T0+1.792 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 -0.42 =B1 0.07,
the high energy photon index beta =3D -2.87 =B1 0.13,
the peak energy Ep =3D 607 =B1 25 keV,
chi2 =3D 77.5/77 dof.
All the quoted results are preliminary.
- GCN Circular #15339
P.A. Evans (U. Leicester) and A. Amral-Rogers (U. Leicester) report on
behalf of the Swift-XRT team:
Using 1.7 ks of XRT Photon Counting mode data and 5 UVOT images for GRB
131014A, 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 = 100.30220, -19.09781 which is equivalent to:
RA (J2000.0) = 06h 41m 12.53s
Dec (J2000.0) = -19d 05' 52.1"
with an uncertainty of 2.3 arcsec (radius, 90% confidence).
This position is 5.9 arcsec from the initial XRT position reported by
Kennea & Rogers (GCN 15335) and 11.2 arcmin from the LAT position
(Desiante et al. (GCN 15333), but 4.1 arcsec from the NOT optical
position of Schulze et al (GCN 15337).
This circular is an official product of the Swift-XRT team.
- GCN Circular #15340
E. Troja (GSFC), Alan M. Watson (UNAM), Nat Butler (ASU),
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 (UCSC),
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=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey
Moseley (GSFC) report:
We observed the field of GRB 131014A (Fitzpatrick et al., GCN 15332,
Desiante, et al., GCN 15333) 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
2013/10 15.36 to 2013/10 15.52 UTC (27.45 to 31.41 hours after the GBM
trigger), obtaining a total of 2.84 hours exposure in the r and i bands,
1.19 hours exposure in the Z and Y bands, and 1.09 hours exposure in the
J and H bands.
For a source within the Swift-XRT error circle (Kennea et al. GCN 15335),
in comparison with 2MASS, we obtain the following measurements:
r 23.42 =B1 0.21
i 22.76 =B1 0.17
Z 23.1 =B1 0.4 (2.7 sigma)
Y 21.20 =B1 0.27
J 21.9 =B1 0.6 (1.8 sigma)
H 21.8 =B1 0.7 (1.6 sigma)
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. The object is located 0.4 arcsec=20
from
the NOT afterglow candidate (Schulze et al., GCN 15337) and consistent=20
with it.
We cannot determine whether the source is fading. No other uncatalogued
source is detected within the XRT error circle.
Despite the large errors, our preliminary analysis indicates a blue=20
continuum in YJH,
suggestive of a possible z-band dropout, and implying a high-redshift (z=20
~ 6) for
GRB 131014A.
Further observations are planned.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedr=
o
M=E1rtir.
- GCN Circular #15342
C. A. Swenson (PSU) and Alex Amaral-Rogers (U Leicester) report
on behalf of the Swift/UVOT team:
The Swift/UVOT began observations of the field of GRB 131014A
starting approximately 45.7 ks after the Fermi LAT detection (Desiante et
al. 2013, GCN 15333). We do not detect any new source consistent
with the NOT afterglow candidate (Schulze et al. 2013, GCN 15337).
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
----------------------------------------------------
u 45,688 74,324 1239 >20.9
----------------------------------------------------
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) = 0.22 mag (Schlegel et al. 1998).
- GCN Circular #15344
A. Amaral-Rogers, P.A. Evans & K.L. Page (U.Leicester) report on behalf of
the Swift-XRT team:
We have analysed 11 ks of XRT data for the Fermi/LAT-detected burst:
GRB 131014A, from 44.1 ks to 173.4 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.
The enhanced XRT position was given in GCN Circ. 15339 (Evans &
Amaral-Rogers).
The light curve can be modelled with a power-law decay with a decay
index of alpha=1.53 (+/-0.28).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.2 (+0.7, -0.6). The
best-fitting absorption column is 6.8 (+4.0, -3.0) x 10^21 cm^-2, in
excess of the Galactic value of 2.2 x 10^21 cm^-2 (Kalberla et al.
2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.9 x 10^-11 (8.5 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 6.8 (+4.0, -3.0) x 10^21 cm^-2
Galactic foreground: 2.2 x 10^21 cm^-2
Excess significance: 2.5 sigma
Photon index: 2.2 (+0.7, -0.6)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020300.
This circular is an official product of the Swift-XRT team.
- GCN Circular #15346
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=F1iga (UNAM), Neil Gehrels (GSFC), and
Harvey Moseley (GSFC) report:
We reobserved the field of GRB 131014A (Fitzpatrick, et al., GCN 15332;
Desiante, et al., GCN 15333) 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
2013/10 16.36 to 2013/10 16.52 UTC (51.38 to 55.33 hours after the
GBM trigger), obtaining a total of 2.11 hours exposure in the r and i ban=
ds
and 0.88 hours exposure in the Z, Y, J, and H bands.
We do not detect the source reported in Troja et al. (GCN 15340).
In comparison with SDSS DR9 and 2MASS, we obtain the following upper
limits (3-sigma):
r >23.8
i >23.4
Z >22.4
Y >21.7
J >21.4
H >20.9
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
We note that the source reported in Troja et al. (GCN 15340) lies within=20
the
XRT localization reported in Kennea et al. (GCN 15335), but is ~4 arcsec
offset from the XRT enhanced position (Evans et al., 15339).
However, the source shows evidence of fading in our latest exposures
(>3 sigma level, i band; 2-sigma level, r and Y band), suggesting that
it is associated with GRB131014A.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedr=
o
M=E1rtir.
- GCN Circular #15347
D. A. Kann (MPE Garching), T. Kruehler (ESO), K. Varela and J. Greiner
(both MPE Garching) report on behalf of the GROND team:
We observed the field of the Fermi GBM/LAT GRB 131014A (Fitzpatrick &
Xiong, GCN #15332) simultaneously in g'r'i'z'JHKs with GROND (Greiner et
al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at La Silla
Observatory (Chile).
Observations started at 07:07 UT on 16 October 2013, 2.08 days after the
GRB. They were performed at an average seeing of 1".0 and at an average
airmass of 1.1. Observations were slightly affected by passing clouds. We
obtained a total exposure of 4500 sec in g'r'i'z' and 3600 sec in JHK.
We detect several sources in and near the refined XRT error circle by
Evans & Amral-Rogers (GCN #15339). Source 1 is the one reported by Schulze
et al. (GCN #15337), also detected by Troja et al. (GCN #15340) and
claimed to be fading by Troja et al. (GCN #15346).
We estimate preliminary magnitudes and upper limits (all in the AB system)
in an aperture of 1".8:
g' = 24.1 =B1 0.2 mag
r' = 22.8 =B1 0.1 mag,
i' = 22.5 =B1 0.1 mag,
z' = 22.2 =B1 0.1 mag,
J > 21.5 mag,
H > 21.0 mag,
K > 19.4 mag
This source lies significantly outside the refined XRT error circle
(Evans & Amral-Rogers, GCN #15339), is extended in our images and we find
no evidence of fading as compared to the earlier (t =3D 1 day) measurement
of Schulze et al. (GCN #15337), also using image subtraction versus the
NOT image. We thus do not consider it the afterglow of GRB 131014A. The
colors and the apparent extent of the source are consistent with a
low-redshift galaxy.
Source 2 is consistent with being point-like in our images and found at:
RA (J2000) = 06:41:12.41
Dec. (J2000) = -19:05:53.5
We estimate preliminary magnitudes and upper limits (all in AB) for a
point source of:
g' > 25.0 mag
r' = 24.8 =B1 0.3 mag,
i' = 23.8 =B1 0.2 mag,
z' = 22.8 =B1 0.1 mag,
J = 21.7 =B1 0.2 mag,
H = 21.6 =B1 0.4 mag,
K > 19.8 mag
This source is extremely red and lies on the edge of the refined XRT error
circle.
Source 3 also lies on the edge of the error circle at
RA (J2000) = 06:41:12.56
Dec. (J2000) = -19:05:50.1
We estimate preliminary magnitudes and upper limits (all in AB) for a
point source of:
g' = 25.1 =B1 0.4 mag
r' = 24.5 =B1 0.2 mag,
i' = 24.1 =B1 0.2 mag,
z' = 23.8 =B1 0.3 mag,
J > 22.0 mag,
H > 21.5 mag,
K > 19.8 mag,
At present, no statement about variability for either source 2 or 3 can be
made.
Magnitudes are calibrated against SDSS (griz) and 2MASS (JHK) stars, and
are not corrected for the Galactic foreground extinction corresponding to
a reddening of E_(B-V)=3D 0.26 mag in the direction of the burst (Schlegel
et al. 1998).
- GCN Circular #15348
T. Kawano, M. Ohno, K. Takaki, R. Nakamura, S. Furui, Y. Fukazawa(Hiroshima
U.), T. Yasuda, M. Tashiro, Y. Terada, Y. Ishida, H. Ueno, S. Sugimoto
(Saitama U.), M. Yamauchi, N. Ohmori, M. Akiyama (Univ. of Miyazaki), K.
Yamaoka (Nagoya U.), S. Sugita (Ehime U.), Y. E. Nakagawa, M. Kokubun, T.
Takahashi (ISAS/JAXA), W. Iwakiri(RIKEN), Y. Hanabata (ICRR), Y. Urata
(NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo) on behalf of the Suzaku
WAM team, report:
The bright, long GRB 131014A (Fermi GBM detection: Fitzpatrick & Xiong, GCN
15332; Fermi LAT detection: Desiante et al., GCN 15333) triggered the
Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50
keV - 5 MeV at UT 05:09:0.269(=T0).
The observed light curve shows a bright peak followed by a weaker emission
seen up to T0+5 s with a duration (T90) of about 3 seconds.
The fluence in 100 - 1000 keV was 2.02 (-0.11, +0.39) x10^-4 erg/cm^2.
The 1-s peak flux measured from T0+1.6 s was 270 (-28, +34) photons/cm^2/s
in the same energy range.
Preliminary result shows that the time-averaged spectrum from T0 s to T0+5
s is well fitted by a GRB Band model as follows.
the low-energy photon index alpha: -0.81 (-0.85, +1.16),
the high-energy photon index beta: -2.95 (-0.40, +0.18),
and the peak energy Epeak: 285 (-88, +33) keV, (chi^2/d.o.f = 24.3/23).
All the quoted errors are at statistical 90% confidence level.
The light curves for this burst will be available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html
- GCN Circular #15351
P.A. Evans and J.P. Osborne (U. Leicester) report on behalf of the
Swift-XRT team
The Swift-XRT localisation of GRB 131014A has unusually significant
uncertainty, which is not included in the positions previously
circulated (GCNs 15335, 15339), or on the website. The afterglow was
detected towards the edge of two of the initial tiled pointings, and
near the centre of a dedicated follow-up pointing. Positions derived
from these individual pointings vary by up to 4" when the Swift star
tracker attitude is used. If we instead create enhanced positions (using
the UVOT to derive the astrometry) we find astrometric corrections of
~5-8", although we find significant variation between these corrections.
This suggests that there is some degeneracy in the aspect solution.
Given this variation we suggest that the XRT position should be assumed
to have an uncertainty of 6", rather than the values previously
announced or posted online. Thus the best available XRT position is
RA, Dec= 100.3033, -19.0971, which is equivalent to:
RA: 06h 41m 12.80s
Dec: -19 05 49.6
with an uncertainty of approx 6". This is the enhanced position derived
from the follow-up observation, which was centred on the afterglow.
Some low-level scatter in the aspect solutions is seen in all enhanced
positions, and is calibrated into our enhanced position errors. GRB
131014A shows an exceptionally large scatter in the aspect solutions
which is not currently understood. Futhermore, as this is a late-time
tiled follow up, where the source is faint and individual exposures are
short, the normal mechanisms which remove outlying aspect solutions
cannot be applied.
- GCN Circular #15363
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,
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C.
Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
K. Yamaoka, M. Ohno, Y. Hanabata, Y. Fukazawa, T. Takahashi, M. Tashiro,
Y. Terada, T. Murakami, and K. Makishima on behalf of the Suzaku WAM team,
S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on
behalf of the Swift-BAT team, and
V. Connaughton, M. S. Briggs, C. Meegan, and V. Pelassa, on behalf of
the Fermi GBM team, report:
The long-duration, intense GRB 131014A (GCN 15332, 15338, 15348) was
observed by Fermi (GBM: trigger 403420143), Konus-Wind, INTEGRAL
(SPI-ACS), Swift (BAT), Suzaku (WAM), and MESSENGER (GRNS), at about
18540 s UT (05:09:00). The burst was outside the coded field of view of
the BAT.
The burst was localized by the Fermi-LAT to a 2290 sq. arcmin. error
circle (1 sigma, GCN 15333), and the X-ray afterglow was found by the
Swift-XRT (GCN 15335).
We have triangulated it to a 3 sigma error box whose
coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
100.286 (06h 41m 09s) -19.130 (-19d 07' 49")
Corners:
100.122 (06h 40m 29s) -19.544 (-19d 32' 39")
100.356 (06h 41m 25s) -19.177 (-19d 10' 38")
100.448 (06h 41m 48s) -18.714 (-18d 42' 52")
100.215 (06h 40m 52s) -19.083 (-19d 05' 00")
---------------------------------------------
The error box area is 251 sq. arcmin, and its maximum dimension is
53 arcmin (the minimum one is 10 arcmin).
The box area is about 10 times smaller than that of the LAT error circle
(2290 sq. arcmin.).
The reported Swift-XRT source (GCN 15339) is inside the box.
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB131014_T18541/IPN/
Some improvement in this triangulation is possible.
- GCN Circular #15364
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 reobserved the field of GRB 131014A (Fitzpatrick, et al., GCN 15332;
Desiante, et al., GCN 15333) 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
from 2013/10 17.36 to 2013/10 17.53 UTC (75.50 to 79.48 hours after the
GBM trigger), and again the next night from 2013/10 18.35 to 2013/10
18.53 UTC (99.18 to 103.48 hours after the GBM trigger), obtaining a
total of 2.3 hours exposure in the r and i bands and 1.0 hours exposure
in the Z, Y, J, and H bands each night.
These observations reach similar depths to prior RATIR observations of th=
e
field (Troja, et al., GCNs 15340, 15346) in which we report a candidate
optical/NIR afterglow, albeit with marginal statistical significance.
Although the optical/NIR candidate afterglow appears fainter in the 2nd
and 3rd nights relative to our 1st night, it is similarly bright in the
4th night as on the 1st night. The co-addition of data from nights 2
through 4 yields flux levels (in all bands) statistically consistent=20
with those
measured on night 1. An image subtraction analysis confirms this result.
We conclude that our source is not the optical/NIR afterglow of GRB=20
131014A.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro
M=E1rtir.
- 1507.06976 from 27 Jul 15
S. Guiriec et al.: GRB 131014A: a Laboratory to Study the Thermal-Like and Non-Thermal Emissions in Gamma-Ray Bursts, and the new
L$_\mathrm{i}^\mathrm{nTh}$-E$_\mathrm{peak,i}^\mathrm{nTh,rest}$ relation
Space Flight Center, (2) University of Maryland College Park, and (3) Center for Research and Exploration in Space Science and Technology)
Evidence has been accumulated on the existence of a thermal-like component during the prompt phase of GRBs. This component, often associated
with the GRB jet's photosphere, is usually subdominant compared to a much stronger non-thermal one. The prompt emission of Fermi GRB 131014A
provides a unique opportunity to study this thermal-like component. Indeed, the thermal emission in GRB 131014A is much more intense than in
other GRBs and a pure thermal episode is observed during the initial 0.16 s. The thermal-like component cools monotonically during the first
second while the non-thermal emission kicks off. The intensity of the non-thermal component progressively increases until being energetically
dominant at late time. This is a perfect scenario to disentangle the thermal component from the non-thermal one. A low-energy spectral index of
+0.6 better fit the thermal component than the typical index value +1 corresponding to a pure Planck function. The non-thermal component is
adequately fitted with a Band function whose low and high energy power law indices are ~-0.7 and <~-3, respectively; this is also statistically
equivalent to a cutoff power law with a ~-0.7 index. This is in agreement with our previous results. Finally, a strong correlation is observed
between the time-resolved luminosity of the non-thermal component, L$_i^{nTh}$, and its corresponding rest frame spectral peak energy,
E$_{peak,i}^{rest,nTh}$, with a slope similar to the one reported in our previous articles. Assuming this relation to be universal for all GRBs
we estimate a redshift of ~1.55 for GRB 131014A that is a typical value for long GRBs. These observational results are consistent with the
models in which the non-thermal emission is produced well above the GRB jet photosphere but they may also be compatible with other scenarios
(e.g., dissipative photosphere) that are not discussed in this article.
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