GRB 121209A
GCN Circular 14045
Subject
GRB 121209A: Swift detection of a burst
Date
2012-12-09T22:09:02Z (13 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
A. Maselli (INAF-IASFPA), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU),
J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL),
C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC),
D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU)
and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift Team:
At 21:59:11 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 121209A (trigger=540964). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 326.801, -8.244 which is
RA(J2000) = 21h 47m 12s
Dec(J2000) = -08d 14' 39"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows multiple peaks
with a total duration of about 60 sec. The peak count rate
was ~3300 counts/sec (15-350 keV), at ~20 sec after the trigger.
The XRT began observing the field at 22:00:43.3 UT, 92.0 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 326.78917, -8.23262 which is equivalent
to:
RA(J2000) = 21h 47m 09.40s
Dec(J2000) = -08d 13' 57.4"
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This
location is 58 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. We
cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (3.81 x
10^20 cm^-2, Kalberla et al. 2005), with an excess column of 2.8
(+2.58/-2.19) x 10^21 cm^-2 (90% confidence).
UVOT data is not yet available.
Burst Advocate for this burst is A. Maselli (maselli AT ifc.inaf.it).
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 14046
Subject
GRB 121209A: UVOT Observation
Date
2012-12-09T22:27:57Z (13 years ago)
From
Mike Siegel at PSU/Swift MOC <siegel@swift.psu.edu>
M. H. Siegel (PSU) and A. Maselli (INAF-IASFPA) report on behalf of the
Swift/UVOT team:
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 96 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag.
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.05.
GCN Circular 14047
Subject
GRB 121209A: PAIRITEL NIR Observations
Date
2012-12-10T03:07:55Z (13 years ago)
From
Adam Morgan at U.C. Berkeley <qmorgan@gmail.com>
A. N. Morgan (UC Berkeley) reports:
We observed the field of GRB 121209A (Maselli et al., GCN 14045) with the
1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began at
2012-Dec-10 01h16m41s UT, ~3.2 hours after the Swift trigger. In mosaics
(effective exposure time of 1940 s) taken simultaneously in the J, H, and
Ks filters, we do not detect any source within the XRT error circle.
post burst
t_mid (hr) exp.(hr) filt U. Limit (3 sig)
3.68 0.54 J > 18.1
3.68 0.54 H > 17.2
3.68 0.54 Ks > 16.2
All magnitudes are given in the Vega system, calibrated to 2MASS. No
correction for Galactic extinction has been made to the above reported
values.
GCN Circular 14048
Subject
GRB 121209A: Gemini-South imaging
Date
2012-12-10T03:50:12Z (13 years ago)
From
Wen-fai Fong at CFA <wfong@cfa.harvard.edu>
W. Fong (Harvard), D. Fox (PSU), E. Berger and R. Chornock (Harvard) report:
"We observed the location of GRB 121209A (Maselli et al., GCN14045) with
the Gemini Multi-Object Spectrograph (GMOS) mounted on the Gemini-South 8-meter
telescope starting on 2012 Dec 10.028 UT (2.68 hr after the BAT trigger).
We obtained 60-sec in each of the r- and i-bands in 0.75" seeing. We do not
detect any optical source within the XRT position reported in GCN 14045,
nor within the latest reported position (
http://www.swift.ac.uk/xrt_unenh_positions/00540964/). Calibrated to stars
in the SDSS DR8 field, we place 3-sigma limits of r > 22.6 mag and i > 23.0
mag on the optical afterglow of GRB 121209A at 2.7 hr after the burst
(uncorrected for Galactic extinction in the direction of the burst).
We thank the Gemini staff for their assistance with these observations."
GCN Circular 14049
Subject
GRB 121209A: GROND optical afterglow candidate
Date
2012-12-10T07:37:57Z (13 years ago)
From
Thomas Kruehler at Dark Cosmology Center <tom@dark-cosmology.dk>
T. Kruehler (DARK/NBI), A. Nicuesa Guelbenzu (TLS Tautenburg)
and J. Greiner (MPE Garching) report on behalf of the GROND team:
We observed the field of the Swift GRB 121209A (Maselli et al., GCN 14045)
simultaneously in g'r'i'z'JHKs with GROND (Greiner et al. 2008, PASP 120, 405)
mounted at the 2.2m MPG/ESO telescope at La Silla Observatory (Chile).
Observations started on December 10, 2012, 00:24 UT which is roughly 2.4 hr
after the trigger. Within the UVOT-enhanced XRT position (see link in Maselli et al.,
GCN 14045), we detect a faint source in the stack of all g'r'i'z' data at:
RA (J2000) = 21:47:08.96
Dec (J2000) = -08:14:06.3
with an estimated uncertainty of 0.5" in each coordinate.
Forcing photometry on this position, we estimate preliminary AB magnitudes and
upper limits in the individual filters of:
g' > 24.0 mag
r' = 23.9 +- 0.3 mag
i' = 23.6 +- 0.4 mag
z' = 23.2 +- 0.3 mag
J > 21.5 mag
H > 21.0 mag
Ks > 19.5 mag
These magnitudes and upper limits are based on images with a mid-time
of 00:59 UT and an effective integration time of 26.4 min in griz and
24.0 min in the JHKs filters. They are calibrated against SDSS and 2MASS field stars
and have not been corrected for the expected Galactic foreground extinction
corresponding to a reddening of E(B-V) = 0.05 mag (Schlegel et al. 1998).
No statement about variability can be made at this point.
GCN Circular 14050
Subject
GRB121209A: RATIR Optical and NIR Upper Limits
Date
2012-12-10T08:06:34Z (13 years ago)
From
Nat Butler at UC berkeley <natxbutler@gmail.com>
GRB121209A: RATIR Optical and NIR Upper Limits
Nat Butler (ASU), Alan Watson (UNAM), Alexander Kutyrev (GSFC), and
Michael Richer (UNAM), on behalf of a larger collaboration, report:
We observed the location of GRB 121209A (Maselli et al., GCN14045)
with the Reionization and Transients Infrared Camera (RATIR;
www.ratir.org) on the 1.5m Harold Johnson Telescope at Sierra San
Pedro Martir on 2012 Dec 10.072 UT (3.72 hr after the BAT trigger).
In integrations spanning approximately one hour, in poor (3") seeing
conditions, no optical or NIR sources are detected within the XRT
error circle (GCN14045). In comparison with SDSS DR8 and 2MASS, we
derive the following (3-sigma) upper limits in the AB magnitude
system:
r' 21.7
i' 22.1
Z 20.5
Y 20.0
J 19.8
H 19.5
These magnitudes are not corrected for Galactic extinction in the
direction of the GRB.
GCN Circular 14051
Subject
GRB 121209A: Enhanced Swift-XRT position
Date
2012-12-10T09:50:09Z (13 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 3204 s of XRT Photon Counting mode data and 9 UVOT
images for GRB 121209A, 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 = 326.78723, -8.23545 which is equivalent
to:
RA (J2000): 21h 47m 8.94s
Dec (J2000): -08d 14' 07.6"
with an uncertainty of 1.5 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 14052
Subject
GRB 121209A: Swift-BAT refined analysis
Date
2012-12-10T12:40:00Z (13 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), A. Maselli (INAF-IASFPA),
D. M. Palmer (LANL), T. Sakamoto (AGU), G. Sato (ISAS),
M. Stamatikos (OSU), J. Tueller (GSFC)
(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 121209A (trigger #540964)
(Maselli, et al., GCN Circ. 14045). The BAT ground-calculated position is
RA, Dec = 326.800, -8.232 deg, which is
RA(J2000) = 21h 47m 12.0s
Dec(J2000) = -08d 13' 55.8"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 60%.
The mask-weighted light curve shows multiple peaks starting at ~T-5 sec,
max peak at ~T+28 sec, and ending at ~T+80 sec. T90 (15-350 keV) is
42.7 +- 2.0 sec (estimated error including systematics).
The time-averaged spectrum from T-2.16 to T+44.28 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.43 +- 0.08. The fluence in the 15-150 keV band is 2.9 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+27.91 sec in the 15-150 keV band
is 3.4 +- 0.3 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/540964/BA/
GCN Circular 14053
Subject
GRB 121209A: Swift-XRT refined Analysis
Date
2012-12-10T15:09:04Z (13 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M.C. Stroh (PSU), D.N. Burrows (PSU), K.L. Page (U. Leicester), C.
Pagani (U. Leicester), A.P. Beardmore (U. Leicester), V. D'Elia (ASDC),
V. Mangano (INAF-IASFPA), J.A. Kennea (PSU) and A. Maselli report on
behalf of the Swift-XRT team:
We have analysed 18 ks of XRT data for GRB 121209A (Maselli et al. GCN
Circ. 14045), from 95 s to 48.0 ks after the BAT trigger. The data
comprise 28 s in Windowed Timing (WT) mode with the remainder in Photon
Counting (PC) mode. The enhanced XRT position for this burst was given
by Goad et al. (GCN. Circ 14051).
The late-time light curve (from T0+5.2 ks) can be modelled with a
power-law decay with a decay index of alpha=1.20 (+/-0.06).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.31 (+/-0.14). The
best-fitting absorption column is 5.3 (+/-0.6) x 10^21 cm^-2, in
excess of the Galactic value of 3.8 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 4.0 x 10^-11 (9.1 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 5.3 (+/-0.6) x 10^21 cm^-2
Galactic foreground: 3.8 x 10^20 cm^-2
Excess significance: 13.4 sigma
Photon index: 2.31 (+/-0.14)
If the light curve continues to decay with a power-law decay index of
1.20, the count rate at T+24 hours will be 0.014 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.8 x
10^-13 (1.3 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00540964.
This circular is an official product of the Swift-XRT team.
GCN Circular 14054
Subject
GRB 121209A: EVLA Observations
Date
2012-12-10T17:18:25Z (13 years ago)
From
Tanmoy Laskar at Harvard U <tanmoylaskar@gmail.com>
T. Laskar, W. Fong, A. Zauderer, and E. Berger (Harvard) report:
"We observed the position of GRB 121209A (Maselli et al; GCN 14045) with
the EVLA beginning on 2012 Dec 10.01 UT (131 minutes after the burst). No
significant radio emission is detected at the enhanced Swift-XRT position
(Goad et al; GCN 14051) or the optical position (Kruehler et al.; GCN
14049), to a three-sigma upper limit of 27.3 uJy at 5.8 GHz."
GCN Circular 14055
Subject
GRB 121209A: CARMA 3mm Observations
Date
2012-12-11T06:05:41Z (12 years ago)
From
Ashley Zauderer at CfA <bevinashley@gmail.com>
A. Zauderer, T. Laskar, W. Fong, and E. Berger (Harvard) report on
behalf of the CARMA Key Project "A Millimeter View of the Transient
Universe":
"We observed the position of GRB 121209A (Maselli et al.; GCN 14045)
with the Combined Array for Research in Millimeter Astronomy beginning
2012 Dec 10.93 (dt=1.0 d) at a mean frequency of ~85 GHz. We do not
detect significant millimeter emission at the enhanced Swift/XRT error
circle (Goad et al.; GCN 14051) or at the position of the GROND optical
afterglow candidate (Kruehler et al.; GCN 14049) to a 3-sigma limit of
0.5 mJy.
We thank the CARMA observers and staff for their support."
GCN Circular 14056
Subject
GRB 121209A: Keck observations
Date
2012-12-11T11:17:36Z (12 years ago)
From
Daniel Perley at Caltech <dperley@astro.caltech.edu>
D. A. Perley (Caltech), S. B. Cenko, A. N. Morgan (UC Berkeley), and T.
Kruehler (DARK) report:
We observed the position of GRB 121209A with the Low Resolution Imaging
Spectrograph (LRIS) on Keck I on the night of UT December 11. We
acquired two 900-second spectra of the GROND afterglow candidate
(Kruehler et al., GCN 14049) at a mean UT of 05:15 (1.30 day after the
burst) followed by single exposure each of U- and I-band imaging at a
mean UT of 06:33 (1.36 day after the burst). The observations were
affected by clouds and poor seeing, especially the imaging epoch.
We detect a source at the position of the GROND object in the I-band
imaging frame. Performing photometry relative to SDSS stars, we measure
a magnitude of
I = 23.2 +/- 0.2 mag (I=23.6 AB)
Which is consistent with the magnitude at 2.4 hours after the burst
reported by Kruehler et al. The lack of fading over this time range
suggests that the source is not a GRB afterglow. However, it may be the
event's host galaxy. Given the bright X-ray afterglow concurrent with
the lack of an optical/IR counterpart in PAIRITEL, Gemini GROND and
RATIR observations (GCNs 14047, 14048, 14049, 14050), GRB 121209A is
"dark" burst (beta_OX ~< 0, taking the GROND host magnitudes as upper
limits).
Preliminary analysis of our 2D spectra shows no evidence of line
emission across the spectral range (effectively continuous from the
atmospheric cutoff to 10300 Angstroms), despite detection of a (weak)
continuum trace down to approximately 10000 Angstroms. If this is a
star-forming galaxy, this absence of lines (in particular, from OII)
would suggest a moderately high redshift (z>~1.7). Deeper spectroscopy
and in particular infrared observations would be needed to confirm this
hypothesis. If this is a distant galaxy, its apparent optical
brightness indicates that it quite luminous.
GCN Circular 14081
Subject
GRB 121209A: Early CARMA Observations
Date
2012-12-14T01:24:38Z (12 years ago)
From
Daniel Perley at Caltech <dperley@astro.caltech.edu>
D. A. Perley and A. Horesh (Caltech) report on behalf of a larger
collaboration:
We observed the position of GRB 121209A (Maselli et al., GCN 14045) with
the Combined Array for Research in Millimeter-Wave Astronomy (CARMA) at
a frequency of 93 GHz (3mm) between 00:46 and 01:14 on 2012-12-10 (UT).
The mean observation time was 3.01 hours after the GRB trigger.
No source is detected at the position of the X-ray afterglow (Goad et
al., GCN 14051) or of the possible host galaxy (GCN 14049, Kruehler et
al.). The 3-sigma limit of the map is 1.8 mJy.
GCN Circular 14084
Subject
GRB 121209A: MAXI/GSC detection
Date
2012-12-14T13:24:21Z (12 years ago)
From
Satoshi Nakahira at JAXA/MAXI <nakahira.satoshi@jaxa.jp>
R. Sato(Kyoto U.), S. Nakahira (JAXA), M. Serino (RIKEN),
Y. Ogawa (Miyazaki U.), N. Kawai (Tokyo Tech),
H. Negoro, M. Asada (Nihon U.),
S. Ueno, H. Tomida, M. Ishikawa, K. Yamaoka, M. Kimura (JAXA),
T. Mihara, M. Sugizaki, K. Morihana, T. Yamamoto, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN),
M. Mori, R. Usui, K. Ishikawa (Tokyo Tech),
A. Yoshida, T. Sakamoto, Y. Nakano (AGU), H. Tsunemi, M. Sasaki (Osaka U.),
M. Nakajima, (Nihon U.), Y. Ueda, K. Hiroi, M. Shidatsu, T. Kawamuro (Kyoto U.),
Y. Tsuboi, M. Higa (Chuo U.)
M. Yamauchi, Y. Nishimura, T. Hanayama, K. Yoshidome (Miyazaki U.)
on behalf of the MAXI team
At 2012-12-09T21:59:11 UT, the MAXI/GSC detected an uncatalogued
X-ray transient source. Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec.) = (327.02deg, -7.69deg) = (21:48:05, -07:41:38)(J2000)
with a 90% C.L. statistical error of 0.4 deg and an additional systematic
uncertainty of 0.1 deg (90% containment radius).
The trigger time is consistent with that of GRB 121209A (Maselli et al, GCN #14045).
The Swift position lies 0.1 deg outside of the MAXI error circle.
However, assuming the position for GRB 121209A, the transit by MAXI
should have occurred from
2012/12/09T21:58:38 UT(=T0-32 s, where T0 is the Swift/BAT trigger time)
to T0+11 s, suggesting that GRB 121209A was detected near the end
of the MAXI transit, causing the small difference in the formal position.
The time interval of the significant MAXI detection was T0+0 s to T0+5 s
with 2-20 keV X-ray flux of 600+/-140 mCrab (2-20 keV).
The average spectrum is fitted by a power-law model with photon index of 0.97(-0.57/+0.62).
There was no significant excess flux at the previous transit at 17:21 UT and
at the next transit at 23:31 UT on Dec 9 with an upper limit of 20 mCrab for each.
GCN Circular 14086
Subject
GRB 121209A: Swift/UVOT Upper Limits
Date
2012-12-14T17:19:02Z (12 years ago)
From
Stefan Immler at NASA/GSFC <stefan.m.immler@nasa.gov>
S. Immler (NASA/CRESST/GSFC) and A. Maselli (INAF-IASFPA)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 121209A
96 s after the BAT trigger (Maselli et al., GCN Circ. 14045).
No optical afterglow consistent with the optical position (Kruehler
et al. GCN Circ. 14049) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 96 246 147 >21.4
white 96 12808 1217 >21.7
v 5857 35749 1967 >20.3
b 5241 24926 1784 >21.1
u 308 30697 1959 >21.6
w1 6267 29936 1968 >21.5
m2 6062 36468 2314 >22.3
w2 5652 34835 1968 >21.8
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.05 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 14087
Subject
GRB 121209A: LOAO Observation
Date
2012-12-15T14:17:50Z (12 years ago)
Edited On
2025-04-09T18:44:22Z (2 months ago)
From
Seong-Kook Lee at CEOU,SNU,Korea <s.joshualee@gmail.com>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Tyler Barna at University of Minnesota <tylerpbarna@gmail.com>
Seong-Kook Lee, Myungshin Im (SNU), and Y. Urata (NCU) report:
We observed the location of GRB 121209A with the ARC Camera mounted on the
1.0m
Telescope at Mt. Lemmon Optical Astronomy Observatory (LOAO) on 2012 Dec
10,
09:06 UT.
We obtained a series of 300 seconds exposure images in I-band and Z-band
under 4" seeing.
We do not detect any source in both bands.
Calibrated to SDSS stars, we derive 3-sigma detection limit (in AB system)
in each band,
I > 20.9
Z > 19.6
We thank KASI staff for their support.