).
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 #17147
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 141207A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00034
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 #17149
A. Amaral-Rogers & P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team:
We have observed the area around the Fermi-LAT GRB 141207A (Arimoto et
al., GCN Circ. 17146), in 4 XRT fields starting at 07:59:28 UT, 12 hours and 48 minutes after Fermi/LAT detection. With 1.3-1.7 ks per field, we find an uncatalogued X-ray source at a position of RA,Dec=160.0639,
3.8933, which is equivalent to:
RA (J2000) = 10h 40m 15.34s
Dec (J2000) = +03d 53' 35.9"
with an uncertainty of 5.2" (radius, 90% confidence). Although this
source is uncatalogued, it is a factor of 3 below the ROSAT limit at
this location, with a 0.3-10 keV flux of 1.7e-13 erg/cm^2/s. We expect
~0.9 sources at this flux to be serendipitously present in our XRT
observations, therefore we caution that this may not be the afterglow.
We cannot currently tell whether the source is fading, but follow-up
observations are planned.
There is a second uncatalogued X-ray source present in the data, at
RA,Dec=159.8172, 4.0930 with an uncertainty of 6.5"; however this source
is coincident with the object [VV2006] J103916.6+040536 which SIMBAD
classifies as a quasar, thus it is unlikely to be the GRB afterglow.
This circular is an official product of the Swift-XRT team.
GCN Circular #17150
Eric Burns (UAH) report on behalf of the Fermi GBM Team:
"At 19:11:21.10 UT on 07 December 2014, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 141207A (trigger 439672284 / 141207800) which
was also detected by Fermi LAT (Arimoto et al. 2014, GCN 17146) and
observed by Swift (Evans 2014, GCN 17147). The GBM on-ground location
is consistent with the LAT/Swift positions.
The angle from the Fermi LAT boresight is 59 degrees.
The GBM light curve consists of a single pulse with multiple spikes,
with a duration (T90) of about 20 s (50-300 keV). The time-averaged
spectrum from T0-0.768 s to T0+24.83 s is adequately fit by a power law
function with an exponential high-energy cutoff. The power law index is
-0.70 +/- 0.02 and the cutoff energy, parameterized as Epeak, is
1080 +/- 56 keV.
The event fluence (10-1000 keV) in this time interval is
(3.58 +/- 0.04)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+7.55 s in the 10-1000 keV band is 8.6 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular #17151
GRB 141207A: Swift-UVOT Observations
M. H. Siegel (PSU) and A. Amaral-Rogers (U. Leicester) report=20
on behalf of the Swift-UVOT team:
We have observed the area around the Fermi-LAT GRB 141207A (Arimoto et
al., GCN Circ. 17146), in 4 UVOT fields starting at 07:59:28 UT, 12
hours and 48 minutes after Fermi/LAT detection. There is an optical sourc=
e
at a position of RA,Dec=3D160.06441, 3.89477, which is
equivalent to:
RA (J2000) = 10h 40m 15.46s
Dec (J2000) = +03d 53' 41.2
with an uncertainty of 0.1 (radius, 90% confidence). This source is
5.6 from the position of the XRT source (Amaral-Rogers and Evans, GCN
Circ. 17149) and shows up as a marginal detection in the DSS. It is possibly
unrelated to the burst. Follow-up observations will be needed to confirm
its nature.
The preliminary u magnitude using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) is 19.91+-0.17.
GCN Circular #17152
V. Toy (UMD), J. Capone (UMD), E. Troja (NASA-GSFC), S.B. Cenko
(NASA-GSFC), A. Cucchiara (NASA-GSFC), A. Kutyrev (NASA-GSFC), and S.
Veilleux (UMD) report on behalf of a larger collaboration:
We observed the field of the Fermi-LAT GRB141207A (Fermi-GBM trigger
439672284/141207800, Arimoto et al., GCN 17146; Burns et al., GCN 17150)
with the Large Monolithic Imager (LMI) on the 4.3m Discovery Channel
Telescope (DCT) at Happy Jack, AZ from 2014/12/08 11:08 to 2014/12/08 12:30
UTC (starting 16.0 hours after the Fermi trigger). We imaged 5 fields
covering the entire 90% LAT error region. No source is detected at the
positions of the two X-ray sources reported by Amaral-Rogers and Evans (GCN
17149). We estimate a 3-sigma upper limit of r > 23.2
(RA,Dec=160.0639,3.8933) and r > 21.3 (RA,Dec=159.8172, 4.0930).
We detect the source reported by Siegel and Amaral-Rogers (GCN 17151) with
r'=20.09+/-0.04. We note that this coincides with a galactic SDSS source,
J104015.45+035341.0.
These magnitudes are reported in AB magnitude and are not corrected for
Galactic extinction in the direction of the GRB.
We thank the staff of the Discovery Channel Telescope for assistance with
these observations.
GCN Circular #17155
S. Golenetskii, R. Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration, hard-spectrum GRB 141207A (Fermi-LAT detection:
Arimoto et al., GCN 17146; Fermi-GBM detection: Burns, GCN Circ. 17150)
triggered Konus-Wind at T0=69081.298 s UT (19:11:21.298).
The burst light curve shows two pulses started at ~T0-2.3 s with a total
duration of ~25 s.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB141207_T69081/
As observed by Konus-Wind, the burst
had a fluence of 4.87(-0.34,+0.38)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+6.224 s,
of 9.62(-2.26,+2.27)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 best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.50 (-0.13,+0.14)
and Ep = 723(-72,+87) keV (chi2 = 105/98 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.6
(chi2 = 104/97 dof)
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular #17157
P.A. Evans, K.L. Page & A. Amaral-Rogers (U. Leicester) report on behalf
of the Swift-XRT team:
Swift has continued to observe the field of the Fermi-LAT GRB 141207A
(Arimoto et al., GCN Circ. 17146). The uncatalogued X-ray source
reported by Amaral-Rogers & Evans (GCN. Circ 17149) shows no evidence of
fading.
An additional uncatalogued X-ray source has also been detected at
RA,Dec=159.8547, 3.71139 degrees, which is equivalent to:
RA (J2000) = 10h 39m 25.13s
Dec (J2000) = +03d 42' 41.0"
with an uncertainty of 4.9 arcsec (radius, 90% confidence). This source
was initially detected with a count-rate of 0.012 +/- 0.003 ct/sec. In a
second observation, from T0+191 ks to T0+231 s, the source has faded to
a count-rate of 1.0 (+/-0.5) x 10^-3 ct/sec. We therefore suggest that
this is likely the afterglow of GRB 141207A.
The PC mode spectrum of this source can be fitted with an absorbed
power-law with a photon index of 2.1 (+1.5, -0.7). The best-fitting
absorption column is 5.2 (+18, -4.8) x 10^21 cm^-2, consistent with the
Galactic value of 0.4 x 10^21 cm^-2 (Willingale et al. 2013).
A summary of the PC-mode spectrum is thus:
Total column: 5.2 (+18, -4.8) x 10^21 cm^-2
Galactic foreground: 3.7 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 2.1 (+1,5, -0.7)
This circular is an official product of the Swift-XRT team.
GCN Circular #17193
T. Fujinuma, M. Tashiro, Y. Terada, T. Yasuda, S. Koyama, S. Takeda,
T. Nagayoshi, J. Enomoto, S. Nakaya, S. Matsuoka (Saitama U.),
M. Yamauchi, N. Ohmori, R. Kinoshita (Univ. of Miyazaki),
W. Iwakiri (RIKEN), K. Yamaoka (Nagoya U.), S. Sugita (Ehime U.),
Y. Hanabata (ICRR), M. Ohno, T. Kawano, S. Furui, Y. Fukazawa
(Hiroshima U.), Y. E. Nakagawa, M. Kokubun, T. Takahashi (ISAS/JAXA),
Y. Urata (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo)
on behalf of the Suzaku WAM team, report:
The long GRB 141207A(Fermi-LAT Detection: Kocevski et al.,GCN 17146;
Swift-XRT observation:Amaral-Rogers et al.,GCN 17149;Fermi GBM dection:
Burns et al.,GCN 17150) triggered the Suzaku Wide-band All-sky Monitor
(WAM) which covers an energy range of 50 keV - 5 MeV at 19:11:22.452 UT
(=T0).
The observed light curve shows a multi-peaked structure starting at
T0-1s, ending at T0+22s with a duration(T90) of about 20 seconds. The
fluence in 100 - 1000 keV was 1.94(+0.10/-0.19)x10^-5 erg/cm^2.The 1-s
peak flux measured from T0+6s was 4.74(+0.37/-1.32) photons/cm^2/s in
the same energy range.
Preliminary result shows that the time-averaged spectrum from T0-1s to
T0+22s is well fitted by a power-law with exponential cutoff model:
dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
alpha 1.11(+0.40/-0.48), and
Epeak 579(+126/-92) keV (chi^2/d.o.f. = 28.2/25).
Due to the brightness of this burst, a 3% systematic error was added for
low energy channels. There might be uncertainty since the response for
the incident angle of GRB photons to WAM is not reliable.
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 #17194
K. Hurley, on behalf of the IPN,
S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks,
D. Svinkin, and T. Cline on behalf of the Konus-Wind team,
D. M. Smith, J. McTiernan, R. Schwartz, W.
Hajdas, and A. Zehnder, on behalf of the RHESSI GRB 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,
J. Goldsten, on behalf of the MESSENGER NS GRB team, and
V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa, and A. Goldstein, on behalf of the Fermi GBM team, report:
GRB 141207A, initially reported by the Fermi LAT and GBM teams (GCN
17146, 17150), was also observed by Konus-Wind, INTEGRAL SPI-ACS, Swift
BAT (outside the coded FoV), MESSENGER GRNS, RHESSI, and Suzaku WAM.
We have triangulated it to a preliminary, 3 sigma annulus centered at
RA(2000), Dec(2000) = 73.658 deg (04h 54m 38s), +23.585 deg (+23d 35'04"),
whose radius is 85.031 +/- 0.100 deg. The XRT source reported in Evans, Page,
& Amaral-Rogers, GCN 17157, lies 0.003 degrees from the center line of this annulus,
supporting the conclusion that this source is the GRB counterpart.
Previous IAU Circulars 