GRB 070714B
GCN Circular 6836
Subject
GRB 070714B: host galaxy spectroscopic redshift
Date
2007-10-02T00:36:25Z (18 years ago)
From
John Graham at STScI <graham@stsci.edu>
J. F. Graham (STScI/JHU), A. S. Fruchter (STScI), A. J. Levan (U.
Warwick), M. Nysewander (STScI), N. R. Tanvir (U. Leicester), T. Dahlen
(STScI), D. Bersier (Liverpool John Moores U.), A. Pe'er (STScI) report
on behalf of a larger collaboration:
Gemini Nod & Shuffle spectroscopy on the host of GRB 070714B shows a
single emission line at 7165 A. A photometric redshift based on Gemini
grizJHK observations with GMOS and NIRI strongly implies that this is
the 3727 A [O II] line. This places the host at a redshift of z=.92
The Swift BAT discovery data show the burst to have had a short, hard
main component of three seconds duration followed by a soft, longer
duration tail (Sakamoto et al. GCN 6623). The main component also shows
a small spectral lag (Norris et al. GCN 6631). Both of these
observations are consistent with GRB 070714B being a short GRB. This
then would be the highest spectroscopically confirmed redshift of a
short burst.
The observed fluence of 7.2 x 10^-7 erg/cm^2 (Barbier et al. GCN 6638)
at a redshift of z=.92 corresponds to an isotropic energy release of
Eiso = 1.6 x 10^51 erg.
GCN Circular 6689
Subject
Swift/UVOT detection of GRB070714B
Date
2007-07-30T21:17:07Z (18 years ago)
From
Wayne Landsman at GSFC/SSAI <landsman@milkyway.gsfc.nasa.gov>
W. Landsman (NASA/GSFC), F.E. Marshall (NASA/GSFC), and J. Racusin (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT observed the field of the short-hard burst GRB 070714B
starting 70 s after the BAT trigger (Racusin et al. GCN Circ.
6620). Upper limits on individual exposures were reported by
Landsman & Racusin (GCN Circ. 6632). We now combine all data
obtained within the first 7350s and find detections in the white (4.5
sigma) and v (3.3 sigma) filters at the position of the source first
reported by Melandri et al. (GCN Circ. 6621). The source is detected
in each of the three UV filters at the ~2.9 sigma level. Presuming the
detection in the UVW2 (2100 A) filter is real, an upper limit of ~1.3
can be set on the redshift.
Filter Tstart Tstop Exp Mag
(s) (s) (s)
White 70 7143 628 20.95 � 0.23
v 177 6117 1435 20.36 � 0.32
7355 87569 4321 >20.9 (3 sigma)
uvw1 607 6528 294 20.14 � 0.38
11649 99315 9741 >22.1 (3 sigma)
uvm2 583 6321 294 20.02 � 0.37
10742 98409 8750 >22.3 (3 sigma)
uvw2 687 7350 471 20.55 � 0.37
16463 104208 5313 >22.1 (3 sigma)
GCN Circular 6685
Subject
VLA upper limit on short hard burst GRB 070714B
Date
2007-07-29T20:09:34Z (18 years ago)
From
Poonam Chandra at U Virginia/NRAO <pc8s@virginia.edu>
Poonam Chandra (NRAO/UVA) and Dale A. Frail (NRAO) report on
behalf of the Caltech-NRAO-Carnegie GRB Collaboration:
"We used the Very Large Array to observe the field of view toward
GRB 070714B (GCN 6620), which was classified as short hard burst
(GCN 6623), at a frequency of 8.46 GHz on 2007 July 29th at 17.47 UT.
The radio afterglow of the GRB is undetected. The flux density of
the GRB at the SWIFT-XRT afterglow position (GCN 6627) is
-42 +/- 45 uJy.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
GCN Circular 6657
Subject
Short-Hard GRB070714B: PROMPT Observations
Date
2007-07-24T15:35:26Z (18 years ago)
From
Christine Weaver at FUNGRB/PROMPT <eweaver9@physics.unc.edu>
C. Weaver, T. Brennan, M. Schubel, J. Styblova, J. Haislip, D. Reichart, M.
Nysewander, A. LaCluyze, K. Ivarsen, J. A. Crain, A. Foster, and A. Trotter
report:
Skynet observed the localization of short-hard GRB 070714B (Racusin et al.,
GCN 6620) with two of the 16" PROMPT telescopes at CTIO beginning 4.5 hours
after the burst in UBV.
We do not detect the afterglow (Melandri et al., GCN 6621) to 3-sigma
limiting magnitudes of B = 19.9 mag at a mean time of 4.9 hours after the
burst (13 x 80 sec, calibrated to 14 USNO B1.0 stars) and V = 19.8 mag at a
mean time of 5.5 hours after the burst (20 x 80 sec, calibrated to 13 NOMAD
stars.
GCN Circular 6652
Subject
GRB 070714B: Keck observations
Date
2007-07-22T20:15:47Z (18 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
GRB 070714B: Keck late-time observations
D. A. Perley, J. S. Bloom (UC Berkeley), C. Thoene (DARK, UCB), and N. R.
Butler (UC Berkeley) report:
On the night of 2007 July 18 (UT) we observed the field of GRB 070714B
with the 10m Keck I Telescope (+LRIS) for 780 seconds in R and 920 seconds
in g', starting at 14:30 UT. We detect a single, very faint source
consistent with the position reported by Melandri et al. (GCN 6621) and
inside the refined (GCN 6627) and improved [1] XRT error circles, in both
filters. The location of this source is:
RA = 03:51:22.23
Dec = +28:17:50.8
(+/- 0.4")
The object has an approximate magnitude of R~25.5, calibrating relative to
the USNO-B2.0 star at (03:51:21.5973, +28:18:55.810). It does not appear
visibly extended in our imaging. This rules out the presence of a bright
host galaxy and, comparing to the magnitude reported by Levan et al. (GCN
6630) suggests a rapid late-time afterglow decay rate of the afterglow.
[1] http://astro.berkeley.edu/~nat/swift/xrt_pos.html
GCN Circular 6638
Subject
GRB 070714B: Swift/BAT and Suzaku/WAM joint spectral analysis
Date
2007-07-19T13:55:47Z (18 years ago)
From
Takanori Sakamoto at NASA/GSFC <takanori@milkyway.gsfc.nasa.gov>
M. Ohno, T. Uehara, T. Takahashi, Y. Fukazawa, C. Kira (Hiroshima U.),
K. Yamaoka, Y. E. Nakagawa, S. Sugita (Aoyama Gakuin U.),
Y. Terada, T. Tamagawa (RIKEN), K. Morigami, N. Kodaka, K. Onda,
M. Tashiro, M. Suzuki, Y. Urata, A. Endo (Saitama U.), T. Enoto,
R. Miyawaki, K. Nakawaza, K. Makishima (Univ. of Tokyo), E. Sonoda,
M.Yamauchi, S. Maeno, H. Tanaka, R. Hara (Univ. of Miyazaki),
M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), S. Hong (Nihon U.),
on behalf of the Suzaku-WAM team,
T. Sakamoto (GSFC/ORAU), L. Barbier (GSFC), S. D. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. Ukwatta (GWU)
on behalf of the Swift-BAT team,
report:
We performed the Swift/BAT, and Suzaku/WAM joint fit spectral
analysis of GRB 070714B (Swift-BAT trigger #284856; Racusin, et al.,
GCN Circ. 6620). The time interval of the spectral data for each
instrument is chosen from T0(WAM) to T0(WAM)+2 sec where
T0(WAM) is the trigger time of WAM at 04:59:29.247 UTC.
The energy ranges which we used in the joint spectral analysis
are 14-150 keV and 100-2000 keV for Swift/BAT and Suzaku/WAM
respectively. The spectral data of two instruments are fit
with the spectral model multiplied by the constant factor to
take into account the systematic uncertainties in the response
matrices of each instrument.
The spectrum is well fit with a power-law with exponential cutoff
model (dN/dE ~ E^{alpha} * exp(-(2+alpha)*E/Epeak)). The constant
factors of each instrument agree within 10%. No systematic residual
from the best fit model is seen in the spectral data of each instrument.
The best fit spectral parameters are: alpha = -0.86 +- 0.10 and
Epeak = 1120 (-380/+780) keV (chi2/dof = 64/69). The energy fluence
in the 15-2000 keV band calculated by a power-law with exponential
cutoff model for this two-second interval is 3.7 (-0.6/+1.3) x 10^-6 erg/cm2
(assuming the constant factor of the BAT is fixed to 1).
All the quoted errors are at the 90% confidence level.
GCN Circular 6637
Subject
GRB 070714B : Suzaku WAM observation of the prompt emission
Date
2007-07-19T13:37:25Z (18 years ago)
From
Makoto Tashiro at Saitama U/Swift <tashiro@phy.saitama-u.ac.jp>
N. Kodaka, M. Tashiro, Y. Urata, A. Endo, K. Onda, M. Suzuki,
K. Morigami (Saitama U.),Y. Terada, T. Tamagawa (RIKEN), M. Ohno,
T. Uehara, T. Takahashi, Y. Fukazawa, C. Kira (Hiroshima U.),
K. Yamaoka, Y. E. Nakagawa, S. Sugita (Aoyama Gakuin U.), T. Enoto,
R. Miyawaki, K. Nakawaza, K. Makishima (Univ. of Tokyo), E. Sonoda,
M.Yamauchi, S. Maeno, H. Tanaka, R. Hara (Univ. of Miyazaki),
M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), S. Hong (Nihon U.),
on behalf of the Suzaku WAM team, report:
The short GRB 070714B (Swift/BAT trigger #284856; Racusin et al.,
GCN 6620; Barbier et al., GCN 6623) triggered the Suzaku Wide-band
All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV
at 04:59:29.247 UT (=T0).
The observed light curve with 1/64 sec resolution shows a multi-peaked
structure with a sharp strong peak at ~T0+0.45 sec. The duration (T90)
was about 2.0 sec.
The fluence in 100 - 1000 keV was (2.3 � 0.2)x10^-6 erg/cm^2, while the
1-s peak flux measured from T0+0 to T0+1 sec was
2.8 � 0.3 photons/cm^2/s in the same energy range.
Preliminary result shows that the time-averaged spectrum from T0+0 to
T0+2 sec is well fitted by a single power-law with a photon index
of 1.3 � 0.2 (chi^2 / d.o.f. = 22/20).
All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.
The light curve data for this burst is available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html
GCN Circular 6635
Subject
GRB070714B: TNG NIR observations
Date
2007-07-17T12:34:16Z (18 years ago)
From
Stefano Covino at Brera Astronomical Observatory <stefano.covino@poste.it>
S. Covino, S. Piranomonte, P. D'Avanzo, L.A. Antonelli, F. de Luise,
M. Pedani, N. Pinilla Alfonso report, on behalf of the CIBO
collaboration:
We observed the field of the short/hard GRB070714B (Racusin et al.,
GCN 6620; Barbier et al., GCN 6623) on July 15 2007 at about 5 UT
with the TNG equipped with NICS in the J and K bands. The
observations were performed at high airmass (higher than 2).
We only marginally detected the afterglow identified by Melandri et
al. (GCN 6621) and Levan et al. (GCN 6630) in the K band at
approximately K~21. In the J band we could only derive a mild 3sigma
upper limit, J > 20.7.
This message may be cited.
GCN Circular 6632
Subject
GRB 070714B: Swift/UVOT Upper Limits
Date
2007-07-16T19:59:10Z (18 years ago)
From
Wayne Landsman at GSFC/SSAI <landsman@milkyway.gsfc.nasa.gov>
W. Landsman (NASA/GSFC) and J. Racusin (PSU) report on behalf of the
Swift/UVOT team:
The Swift/UVOT observed the field of GRB 070714B starting 70 s after the
BAT trigger (Racusin et al. GCN Circ.6620). We do not find any source,
in any of the UVOT observations, inside the refined XRT error circle
(Racusin et al., GCN Circ. 6627), or at the location of the Liverpool
source (Melandri et al., GCN Circ. 6621).
The 3-sigma upper limits for detecting a source inside the refined XRT
error circle are:
Filter T_start T_end Exp(s) Mag (3-sigma upper limit)
White 70 170 98.2 > 20.4
v 177 577 393.4 > 19.6
b 657 1637 58.1 > 19.2
u 632 1766 89.2 > 19.2
uvw1 607 1750 97.3 > 19.1
uvw2 687 1676 77.8 > 19.2
The values quoted above are not corrected for the expected Galactic
extinction
corresponding to a reddening of E_{B-V} = 0.14 mag in the direction of the
burst (Schlegel et al. 1998).
GCN Circular 6631
Subject
GRB 070714B: Swift-BAT spectral lag for the SHB
Date
2007-07-16T18:48:06Z (18 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
J. Norris (Stanford U), S.D. Barthelmy (GSFC), T. Ukwatta (GWU)
on behalf of the Swift-BAT team:
Using the event-by-event data from Swift-BAT, the spectral lag
for GRB 070714B (Racusin, et al., 6620; Barbier, et al., 6623) is:
9 ms +- 4 ms (100-350 to 25-50 keV)
14 ms +- 7 ms ( 50-100 to 15-25 KeV)
using 4-msec binning (for the 2.9-sec interval covering the initial spike).
This is consistent with "zero lag" for short hard bursts.
GCN Circular 6630
Subject
GRB 070714B: confirmation of optical afterglow
Date
2007-07-15T21:42:36Z (18 years ago)
From
Andrew Levan at U.of Leicester <anl@star.le.ac.uk>
A.J. Levan (Warwick), N.R. Tanvir (Leicester), D Bonfield (Oxford), Alejo
Martinez-Sansigre (MPI Heidelberg), J. Graham, A. Fruchter (STScI)
report on behalf of a larger collaboration:
We imaged the field of GRB 070714B (Racusin et al. GCNC 6620) with the William
Herschel Telescope (WHT), obtaining at total of 2700s of observations in the
R-band, beginning on July 15 04:17 UT. At the position of the afterglow
candidate of Melandri (GCNC 6621), we detect an object with a magnitude of
R~23.5 (relative to two USNO stars within the field). The observed fading
confirms the association with GRB 070714B. Further observations will be
necessary to determine if the current magnitude is significantly contaminated
by an underlying host galaxy.
GCN Circular 6627
Subject
GRB070714B: Swift-XRT refined analysis
Date
2007-07-15T03:33:26Z (18 years ago)
From
Judith Racusin at PSU <racusin@astro.psu.edu>
J. Racusin, J. Kennea, C. Pagani, L. Vetere (PSU), and P. Evans (U.
Leicester) report on behalf of the Swift/XRT team:
We have analyzed the first 15 ks of Swift XRT PC and WT data from GRB
070714B (Racusin et al., GCN 6620). Using 770 s of overlapping XRT Photon
Counting mode and UVOT V-band data, 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 = 57.84287, 28.29782 which is
equivalent to:
RA (J2000): 03h 51m 22.29s
Dec (J2000): +28d 17' 52.2"
with an uncertainty of 1.8 arcsec (90% confidence, radius). This is 35
arcsec from the refined BAT position (Barbier et al., GCN 6623), and 1.4
arcsec from the Liverpool optical afterglow candidate (Melandri et al.,
GCN 6621).
The XRT light curve shows a fading behavior with super-imposed small
flaring. The light curve can be fit with a power-law beginning with a
steep decay with a slope of 2.49 +/- 0.18 followed by a plateau beginning
at 413s +/- 50s with a slope of 0.60 +/- 0.29 until another break at 1187
+/- 270s with a decay of 1.73 +/- 0.11.
The X-ray PC and WT spectrum is well fit by an absorbed power law with a
photon index for 1.2 +/- 0.1 and a column density of 13 +/- 3 e20 cm^-2 in
excess of the galactic value (6.4e20 cm-2). The absorbed (unabsorbed)
0.3-10.0 keV flux of the WT spectrum is 9.2e-10 (1.0e-9) erg cm^-2s^-1 and
the flux of the PC spectrum is 3.4e-12 (3.7e-12) ergs cm^-2 s^-1.
Assuming the source continues to decay at the same rate, we predict an XRT
count rate of 2.7e-4 counts/s at T0+24 hours, which corresponds to an
observed (unabsorbed) flux of 1.8e-13 (2.0e-13) ergs cm^-2 s^-1.
This circular is an official product of the Swift XRT team.
GCN Circular 6625
Subject
GRB 070714b ("Bastille"): Optical Pre-Imaging (Clarification)
Date
2007-07-14T23:25:42Z (18 years ago)
From
Josh Bloom at UC Berkeley <jbloom@astron.berkeley.edu>
J. S. Bloom notes:
"We clarify that the imaging information reported in the circular GCN
6624 (Nugent & Bloom) refers to GRB 070714b (short-hard burst;
Barbier et al. 6623; trigger #284856) and not GRB 070714a (short and
XRF-like; Barthelmy et al. 6622; trigger #284850). We apologize for
any confusion and thank S. Barthlemy for alerting us to the citation
error in the previous circular.
The corrected circular should read:
GRB 070714b ("Bastille"): Optical Pre-Imaging
P. Nugent (LBL) and J. S. Bloom (UC Berkeley) report:
"We have created a stacked image through the co-addition of 8
unfiltered images taken by the NEAT collaboration and 51 images in
the RG610 filter taken by the Palomar-Quest Consortium at the Palomar
Oschin Schmidt telescope (obtained from 2002-2006), of what is being
called a short-hard burst (SHB) 070714B (Barbier et al.; GCN #6623).
The stacked image is significantly deeper than the DSS (3 sigma limit
of R~22.7 mag). There is no source at the position of the proposed
counterpart (Melandri et al. GCN #6621). Since this Liverpool
Telescope source was detected in twilight, it was likely seen near
the DSS limit (or brighter) and thus, while we cannot say for sure
(since no magnitude was given in GCN #6621), the absence of a
similarly bright source in our image suggests that the Melandri et
al. source was indeed the afterglow.
Note that the source @ position RA = 03:51:21.24, DEC = +28:17:45.5
is in the 2MASS catalog and is blue (J - K = 0.5 mag).
This message may be cited."
GCN Circular 6623
Subject
GRB 070714B, Swift-BAT refined analysis of the short hard burst
Date
2007-07-14T21:47:27Z (18 years ago)
From
Takanori Sakamoto at NASA/GSFC <takanori@milkyway.gsfc.nasa.gov>
L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC),
E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC),
J. Racusin (PSU), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-120 to T+182 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 070714B (trigger #284856)
(Racusin, et al., GCN Circ. 6620). The BAT ground-calculated position is
RA, Dec = 57.853, 28.294 deg which is
RA(J2000) = 3h 51m 24.8s
Dec(J2000) = 28d 17' 37"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 93%.
The BAT mask-weighted light curve shows multiple short spikes starting from
T-0.8 sec with a duration of 3 sec. There is extended softer emission from
T+20 sec to T+70 (and possibly T+100) sec. T90 (15-350 keV) is 64 +- 5 sec
(estimated error including systematics). The light curve looks similar to
previous short bursts such as GRB 050724 with a short-hard initial episode
followed by a softer extended episode, so we think it is likely that this
burst is in the short category.
The time-averaged spectrum from T-0.8 to T+65.6 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.36 +- 0.19. The fluence in the 15-150 keV band is 7.2 +- 0.9 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.39 sec in the 15-150 keV band
is 2.7 +- 0.2 ph/cm2/sec. Separating out the initial "spike" of emission
(from T-0.8 to T+2 sec), the photon index in a simple power-law fit is
0.99 +- 0.08. The fluence in the 15-150 keV band of this part is
5.1 +-0.3 x 10^-7 erg/cm2. All the quoted errors are at the 90% confidence
level.