GRB 130609B
GCN Circular 14841
Subject
GRB 130609B: Swift detection of a burst with an optical counterpart
Date
2013-06-09T21:46:41Z (12 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
H. A. Krimm (CRESST/GSFC/USRA), S. D. Barthelmy (GSFC),
D. N. Burrows (PSU), J. A. Kennea (PSU), D. Malesani (DARK/NBI),
C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC) and
A. Maselli (INAF-IASFPA) report on behalf of the Swift Team:
At 21:38:40 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 130609B (trigger=557828). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 53.754, -40.153 which is
RA(J2000) = 03h 35m 01s
Dec(J2000) = -40d 09' 11"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows multiple peaks
with a total duration of at least 200 sec. The peak count rate
was ~8500 counts/sec (15-350 keV), at ~2 sec after the trigger.
The XRT began observing the field at 21:39:56.4 UT, 76.0 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 53.7695, -40.1747 which is equivalent to:
RA(J2000) = +03h 35m 4.68s
Dec(J2000) = -40d 10' 28.9"
with an uncertainty of 4.9 arcseconds (radius, 90% containment). This
location is 89 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy.
UVOT took a finding chart exposure of nominal 150.000 seconds with the White
filter starting 84 seconds after the BAT trigger. There is a candidate
afterglow in the list of sources generated on-board at
RA(J2000) = 03:35:05.11 = 53.77128
DEC(J2000) = -40:10:26.6 = -40.17406
with a 90%-confidence error radius of about 1.10 arc sec. This position is 5.4
arc sec. from the center of the XRT error circle. The estimated magnitude is
15.71. No correction has been made for the expected extinction corresponding to
E(B-V) of 0.01.
Burst Advocate for this burst is H. A. Krimm (krimm AT milkyway.gsfc.nasa.gov).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
GCN Circular 14847
Subject
GRB 130609B: Enhanced Swift-XRT position
Date
2013-06-10T06:30:59Z (12 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 2407 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 130609B, 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 = 53.77097, -40.17407 which is equivalent
to:
RA (J2000): 03h 35m 5.03s
Dec (J2000): -40d 10' 26.7"
with an uncertainty of 1.7 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 14852
Subject
GRB 130609B: Swift-XRT refined Analysis
Date
2013-06-10T14:46:03Z (12 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
C. Pagani (U. Leicester), A. Melandri (INAF-OAB), B. Sbarufatti
(INAF-OAB/PSU), G. Stratta (ASDC), D.N. Burrows (PSU), J.A. Kennea
(PSU), M.C. Stroh (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester) and H.A. Krimm report on behalf of the Swift-XRT team:
We have analysed 7.0 ks of XRT data for GRB 130609B (Krimm et al. GCN
Circ. 14841), from 66 s to 46.7 ks after the BAT trigger. The data
comprise 1.4 ks in Windowed Timing (WT) mode (the first 9 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Goad et al.
(GCN. Circ 14847).
The late-time light curve (from T0+5.4 ks) can be modelled with an
initial power-law decay with an index of alpha=1.42 (+0.14, -0.56),
followed by a break at T+13.6 ks to an alpha of 2.36 (+0.38, -0.22).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.840 (+/-0.029). The
best-fitting absorption column is 1.40 (+0.08, -0.07) x 10^21 cm^-2,
in excess of the Galactic value of 1.4 x 10^20 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 2.01 (+/-0.10) and a
best-fitting absorption column of 1.28 (+0.26, -0.24) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.7 x 10^-11 (5.0 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.28 (+0.26, -0.24) x 10^21 cm^-2
Galactic foreground: 1.4 x 10^20 cm^-2
Excess significance: 7.6 sigma
Photon index: 2.01 (+/-0.10)
If the light curve continues to decay with a power-law decay index of
2.36, the count rate at T+24 hours will be 8.4 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.1 x
10^-13 (4.1 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/00557828.
This circular is an official product of the Swift-XRT team.
GCN Circular 14856
Subject
Konus-Wind observation of GRB 130609B
Date
2013-06-10T16:22:33Z (12 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
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 intense GRB 130609B
(Swift-BAT trigger 557828: Krimm, et al., GCN 14841)
triggered Konus-Wind at T0=77916.818 s UT (21:38:36.818)
The light curve consists of two major emission episodes:
the first one with a bright multi-peaked structure from ~T0-30 s to ~T0+55 s,
and the second, much weaker and softer episode, from ~T0+170 s to ~T0+210 s.
The emission is seen up to 7 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB130609_T77916/
As observed by Konus-Wind, the burst
had a fluence of (9.4 � 0.7)x10-5 erg/cm2,
and a 64-ms peak flux, measured from T0+3.712 s,
of (9.5 � 0.6)x10-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the first emission episode
(measured from T0 to T0+54.528 s)
is best fit in the 20 keV - 18 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.84 � 0.05,
the high energy photon index beta = -2.39 � 0.15,
the peak energy Ep = 397 � 26 keV,
chi2 = 97/97 dof.
The time-averaged spectrum of the second emission episode
(measured from T0+169.216 to T0+210.176 s)
is best fit in the 20 keV - 18 MeV range
by the cutoff power law with the following model parameters:
the photon index alpha = -1.64 � 0.21,
the peak energy Ep = 198 � 105 keV,
chi2 = 93.7/98 dof.
The spectrum at the maximum count rate
(measured from T0 to T0+6.656 s)
is best fit in the 20 keV - 18 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.70 � 0.07,
the high energy photon index beta = -3.0 � 0.3,
the peak energy Ep = 740 � 90 keV,
chi2 = 105/97 dof.
All the quoted results are preliminary.
GCN Circular 14857
Subject
GRB 130609B: Swift/UVOT Observations
Date
2013-06-10T16:46:41Z (12 years ago)
From
Mike Siegel at PSU/Swift MOC <siegel@swift.psu.edu>
M. H. Siegel (PSU) and H. A. Krimm (CRESST/GSFC/USRA)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 130609B
85 s after the BAT trigger (Krimm et al., GCN Circ. 14841).
A fading source consistent with the XRT position (Goad et al. GCN Circ.
14847) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 03:35:05.11 = 53.77128 (deg.)
Dec (J2000) = -40:10:26.7 = -40.17409 (deg.)
with an estimated uncertainty of 0.50 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 first and second orbit
exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white (fc) 84 234 147 15.47+-0.02
white 577 1891 283 17.36+-0.03
white 6046 7681 393 18.39+-0.05
v 799 1941 136 16.89+-0.09
v 6457 6657 196 18.00+-0.15
b 552 1866 136 17.32+-0.06
b 5841 7476 393 18.46+-0.09
u (fc) 297 546 245 16.31+-0.04
u 700 1841 116 17.15+-0.08
u 5636 7271 393 18.15+-0.09
uvw1 676 1816 136 17.61+-0.12
uvw1 5432 7067 393 18.75+-0.15
uvm2 823 1791 116 19.12+-0.35
uvm2 6662 6861 196 >19.66
uvw2 603 1916 116 >19.51
uvw2 6252 7855 362 >20.39
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 14862
Subject
GRB 130609B, Swift-BAT refined analysis
Date
2013-06-10T21:39:05Z (12 years ago)
From
Hans Krimm at NASA-GSFC <hans.krimm@nasa.gov>
A. Y. Lien (NASA/GSFC/ORAU), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 130609B (trigger #557828)
(Krimm, et al., GCN Circ. 13841). The BAT ground-calculated position is
RA, Dec = 53.776, -40.168 deg which is
RA(J2000) = 03h 35m 06.2s
Dec(J2000) = -40d 10' 04.0"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 43%.
The mask-weighted light curve shows an initial complex of two main
overlapping peaks with numerous subsidiary peaks, with strong emission
between T-10 and T+50 sec and low-level emission between T-30 and T+120 sec.
The highest points are at T+4 and T+18 sec. Then there is a second, weaker
and softer pair of overlapping peaks between T+160 sec and T+220 sec. This
second set of peaks is consistent with a flare seen in the Swift-XRT.
T90 (15-350 keV) is 191.98 +- 2.44 sec (estimated error including systematics)
We note that receipt of the full event data for GRB 130609B may reveal
further late-time peaks and require a revision of the T90 estimate. We will
report on the full data set in a later Circular.
The time-averaged spectrum from T-7.84 to T+213.25 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.23 +- 0.04. The fluence in the 15-150 keV band is 1.6 +- 0.0 x 10^-05
erg/cm2. The 1-sec peak photon flux measured from T+16.78 sec in the 15-150 keV
band is 8.5 +- 0.4 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/557828/BA/
GCN Circular 14866
Subject
GRB 130609B: GROND observations
Date
2013-06-11T13:16:42Z (12 years ago)
From
Andrea Rossi at TLS Tautenburg <rossi@tls-tautenburg.de>
S. Schmidl, A. Rossi (both TLS Tautenburg), and J. Greiner (MPE
Garching) report on behalf of the GROND team:
We observed the field of GRB 130609B (Swift trigger 557828; Krimm et
al., GCN #14841) simultaneously in g'r'i'z'JHK with GROND (Greiner
et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope
at La Silla Observatory (Chile).
Observations started at 09:30 UT on 11th June 2013, 35.9 hours after
the GRB trigger. They were performed at an average seeing of 1.6"
and at an average airmass of 2.2.
We detect a source at the position of the UVOT afterglow (Siegel
et al.; GCN #14857), and based on images taken at a mid-time of
09:45 UT, with total exposures of 25 minutes in g'r'i'z' and 20
minutes in JHK, we estimate preliminary magnitudes (all in AB) of
g' = 22.2 +/- 0.1 mag,
r' = 21.7 +/- 0.1 mag,
i' = 21.1 +/- 0.2 mag,
z' = 20.9 +/- 0.2 mag,
J = 20.6 +/- 0.3 mag,
H = 19.8 +/- 0.4 mag, and
K = 19.4 +/- 0.4 mag.
The source is brighter than what one could expect extrapolating
the early UVOT data (Siegel et al.; GCN #14857) and could be either
a plateau/flare, or due to the contribution of the host galaxy.
Given magnitudes are calibrated against GROND zeropoints as well as
2MASS field stars and are not corrected for the expected Galactic
foreground extinction corresponding to a reddening of E_(B-V)=0.01 mag
in the direction of the burst (Schlegel et al. 1998).
GCN Circular 14867
Subject
GRB 130609B, Further Swift-BAT refined analysis
Date
2013-06-11T13:22:03Z (12 years ago)
From
Hans Krimm at NASA-GSFC <hans.a.krimm@nasa.gov>
H. A. Krimm (GSFC/USRA) and J. R. Cummings (GSFC/UMBC)
for the Swift-BAT team:
Using the full data set from T-239 to T+963 sec from the recent telemetry
downlink, we report final analysis of BAT GRB 130609B (trigger #557828)
(Krimm, et al., GCN Circ. 14841; Lien at al., GCN Circ. 14862).
In addition to the peaks described in Lien at al., GCN Circ. 14862, we report
that there is a small peak in the BAT at around T+270 sec, coincident with a
second flare in the XRT. T90 (15-350 keV) is 210.6 +- 15.1 sec (estimated
error including systematics).
The time-averaged spectrum from T-7.8 to T+307.6 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.32 +- 0.04. The fluence and peak photon flux are as reported in GCN Circ.
14862. The quoted error is at the 90% confidence level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/557828/BA/
GCN Circular 14869
Subject
GRB 130609B: Fermi GBM observation
Date
2013-06-11T14:52:13Z (12 years ago)
From
Veronique Pelassa at UAH <vero.pelassa@gmail.com>
V. Pelassa (UAH) reports on behalf of the Fermi GBM Team:
"At 21:38:35.61 UT on 09 June 2013, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 130609B (trigger 392506718 / 130609902),
which was also detected by the Swift/BAT (H.A. Krimm et al. 2013, GCN 14841).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 117 degrees.
The GBM light curve consists of two bright peaks within 30s of trigger
and a fainter bump at 170s after trigger with a duration (T90) of about
191 s (50-300 keV).
The time-averaged spectrum from T0+0.003s to T0+28.672s is well 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 536 +/- 18 keV
(Castor statistics 474 for 365 d.o.f.).
The event fluence (10-1000 keV) in this time interval is
(6.02 +/- 0.07)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+6.592 s in the 10-1000 keV band is 13.6 +/-0.4 ph/s/cm^2.
A Band function fits the spectrum equally well (Castor statistics 468
for 364 d.o.f.)
with Epeak= 491 +/- 20 keV, alpha = -0.66 +/- 0.02 and beta = -2.6 +/- 0.2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 14888
Subject
GRB 130609B: Theoretical redshift estimation
Date
2013-06-12T18:57:55Z (12 years ago)
From
Remo Rufinni at ICRA <ruffini@icra.it>
R. Ruffini, C.L. Bianco, M. Enderli, M. Muccino, A.V. Penacchioni, G.B. Pisani, J.A. Rueda, N. Sahakyan, Y. Wang, L. Izzo report:
The late X-ray observations of GRB 130609B evidences a pattern typical of a family of GRBs associated to Supernovae following the Induced Gravitational Collapse (IGC) paradigm. We estimate a cosmological redshift for the GRB of approximately z=1.3. We encourage observations.
GCN Circular 14915
Subject
GRB 130609B: Suzaku WAM observation of the prompt emission
Date
2013-06-18T02:17:01Z (12 years ago)
From
Masanori Ohno at Hiroshima U <ohno@hep01.hepl.hiroshima-u.ac.jp>
K. Takaki, M. Ohno, T. Kawano, R. Nakamura, S. Furui, Y. Fukazawa
(Hiroshima U.),
M. Tashiro, Y. Terada, T. Yasuda, Y. Ishida, H. Ueno, S. Sugimoto (Saitama
U.),
K. Yamaoka (Nagoya U.), M. Yamauchi, M. Akiyama, N. Ohmori (Univ. of
Miyazaki),
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 long GRB 130609B (Krimm et al., GCN14841) triggered by the
Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of
50 keV - 5 MeV at 21:38:35 UT (=T0).
The observed light curve shows a multi-peaked structure starting at T0,
ending
at T0+30 s with a duration (T90) of about 19.6 seconds. The fluence in
100 - 1000 keV was 3.77 (+0.24/-0.70) x10^-5 erg/cm^2. The 1-s peak
flux measured
was 7.03 (+0.39/-2.80) photons/cm^2/s in the same energy range.
Preliminary result shows that the time-averaged spectrum from
T0 to T0+30 s is well fitted by a power-law with exponential cutoff model:
dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
alpha 1.48 (+0.40/-0.41), and
Epeak 845 (+179/-147) keV (chi^2/d.o.f. = 15.2/24).
Due to the brightness of this burst, a 5% systematic error was added
for low energy channels.
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