GRB 100205A
GCN Circular 10399
Subject
GRB 100205A: Keck limits on an underlying host galaxy
Date
2010-02-10T13:06:10Z (17 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
D. A. Perley, J. S. Bloom, S. B. Cenko, B. E. Cobb, A. N. Morgan, A. A.
Miller, and C. R. Klein (UC Berkeley) report:
We conducted a deep optical imaging integration on the field of GRB
100205A (Racusin et al., GCN 10361) using LRIS on the Keck I 10m
telescope starting at 09:48 UT on 2010 Feb 7. We integrated for a total
exposure time of 4000 seconds in g-band and 3770 seconds in R-band
simultaneously under clear skies but variable and generally poor seeing
conditions (1.5 arcsec average). The mid-point of the integration was
at 10:28 UT.
We detect no source at the position of the putative infrared afterglow
(Tanvir et al., GCN 10366). Calibrating relative to USNOB1.0, we
measure limiting magnitudes (3-sigma) of:
R > 26.7
g > 26.6
as measured at the afterglow location. A faint source is marginally
detected (<2 sigma) in R-band only at the northwestern edge of the XRT
error circle (Evans et al., GCN 10367), not consistent with the position
of the infrared afterglow.
We also stacked the R-band and g-band images together to create a
white-light composite image. There is no significant detection in this
image, with an approximate limiting magnitude of White > 27 mag.
All properties of this GRB are consistent with it being at high redshift:
* Lack of optical detection starting at early times (e.g. Malesani et
al., GCN 10362; Updike et al., GCN 10364; Cobb et al, GCN 10365)
* An apparently fading afterglow candidate detected only in H- and
K-bands (Cucchiara et al., GCN 10374; Im et al., GCN 10398)
* Limited X-ray absorption: excess N_H(z=0) = 7(+6/-5) x 10^20 cm^-2
(Starling and Racusin, GCN 10369), generally suggestive of higher
redshift (Grupe et al. 2007, AJ 133:2216G) and inconsistent with the
alternative hypothesis of a large extinction column at low redshift for
typical values of A_V/N_H.
* Lack of host galaxy to deep limits (Perley et al. 2009, AJ 138:1690)
As mentioned by Cucchiara et al., the implied redshift of this GRB if
the red H-K color is due to Lyman-alpha absorption would be z ~ 11-13.
However, significant dust absorption at intermediate redshift (e.g.,
A_V~3 mag at z~4) is still generally consistent with the available data,
and unfortunately the X-ray afterglow is too faint to impose meaningful
constraints on extinction in the K-band during the Gemini observation.
An image of the field is posted to:
http://lyra.berkeley.edu/~dperley/100205a/100205a_keck_gR.png
We encourage continued deep infrared follow-up of the field.
GCN Circular 10398
Subject
GRB 100205A: BOAO/LOAO zYJK observation
Date
2010-02-09T14:50:50Z (17 years ago)
From
Myungshin Im at Seoul Nat U <mim@astro.snu.ac.kr>
M. Im, Y. Jeon, W. Park (CEOU/Seoul National Univ),
H.-I. Sung (KASI) and Y. Urata (NCU) on behalf of EAFON team.
We observed the GRB100205A (GCN 10361 Racusin et al.)
with J and K-band using KASINICS instrument on the 1.8m telescope
at the Bohyunsan Optical Astronomy Observatory (BOAO), Korea,
starting from 2010-02-05, 17:28:13 UT. We also observed the GRB
with z and Y filters using the LOAO 1-m telescope,
starting from 2010-02-05, 10:37:51 UT.
We do not detect the afterglow at the reported position
(GCN 10361.; GCN 10366, Tanvir et al.) in any of the bands
with the upper limits summarized below.
Our non-detection in K suggests that the afterglow candidate
faded since the report of the K-band detection (GCN 10366;
GCN 10374 Cucchiara et al.), confirming that it is
an afterglow. The values for J and K-bands are preliminary,
and we are refining the photometry. The data analysis of
the 2nd night follow-up observation (z,Y) is on-going.
Filter z Y J K
-------------------------------------------------
3-sigma limit (AB) 22.3 20.8 22.3 22.5
mid-point(UT,hh:mm) 12:11 11:07 17:43 19:01
We thank the LOAO operator, J. Yoon for his assistance for this
observation.
GCN Circular 10383
Subject
GRB 100205A: GROND upper limits
Date
2010-02-06T20:58:37Z (17 years ago)
From
Ana Nicuesa at TLS Tautenburg <ana@tls-tautenburg.de>
A. Nicuesa (Tautenburg Obs.), T. Kruehler (MPE), A. Rossi (Tautenburg
Obs.) and J. Greiner (MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 100205A (Swift trigger #411248; Racusin et
al., GCN #10361) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at LaSilla
Observatory (Chile).
Due to cloud coverage, observations started only on 05 Feb. 2010 at
06:37:58 UT, 2.3 h after the burst, and were severely affected by passing
cirrus.
In stacked images with a total integration time of 12 minutes in JHK and
13 minutes in g'r'i'z' we do not detect the NIR afterglow candidate
reported by Tanvir et al. (GCN #10366) down to the following limits, all
in the AB system:
g' > 22.8,
r' > 23.0,
i' > 22.4,
z' > 22.2,
J > 21.0,
H > 20.6 and
K > 20.3
These upper limits have been obtained using SDSS and 2MASS field stars as
reference, and are consistent with the magnitudes reported by
Cucchiara et al. (GCN #10374).
GCN Circular 10375
Subject
GRB100205A: CFHT z'-band observation
Date
2010-02-06T13:41:45Z (17 years ago)
From
Yuji Urata at Nat. Central U. <urata@astro.ncu.edu.tw>
Y.Urata (NCU), K.Y. Huang (ASIAA), M. Im (SNU)
report on behalf of EAFON:
"We have imaged the field of GRB100205A (Racusin et al. GCN 10361)
using CFHT. The observation was started at 7:11UT on Feb. 6 (about
26.9 hr after the burst). The z'-band stacked image shows no source
at the position of the NIR afterglow (Tanvir et al. GCN 10366) down to
z'~24.5."
GCN Circular 10374
Subject
GRB 100205A: Gemini-N + NIRI photometry
Date
2010-02-05T21:18:42Z (17 years ago)
From
Antonino Cucchiara at PSU <cucchiara@astro.psu.edu>
A. Cucchiara (PSU), D. B. Fox (PSU), N. R. Tanvir (U. Leicester),
A. J. Levan (U. Warwick), B. E. Cobb (UC Berkeley), E. Berger
(Harvard/CfA),
and R. Chornock (Harvard/CfA) report on behalf of a larger collaboration:
We have calibrated the JHK photometry for the candidate Gemini-N + NIRI
afterglow (Tanvir et al., GCN 10366) of GRB 100205A (Racusin et al.,
GCN 10361) against two 2MASS stars in the field. Converted to AB
magnitudes we find:
J_AB > 23.37 mag (1-sigma UL)
H_AB = 23:54 +- 0.22 mag
K_AB = 21.91 +- 0.20 mag
Thus, based on our photometry we measure a red K-H color, K_AB - H_AB =
1.6 +- 0.5 mag.
If this red color is due to Lyman-alpha absorption within the H filter
bandpass, then
this would imply a redshift of 11 <~ z <~ 13.5. In this connection, we
note that we are
retracting our earlier claim of a J-band detection (Tanvir et al., GCN
10366) at the
candidate position.
Lower-redshift solutions with significant local (host) extinction,
unusual afterglow
colors, or substantial contributions from an underlying host galaxy
cannot be
excluded at this time.
GCN Circular 10371
Subject
GRB 100205A: Swift-BAT refined analysis
Date
2010-02-05T18:16:34Z (17 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
T. Sakamoto (GSFC/UMBC), 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/UMD), D. M. Palmer (LANL),
J. L. Racusin (NASA/GSFC), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 100205 (trigger #411248)
(Racusin, et al., GCN Circ. 10361). The BAT ground-calculated position is
RA, Dec = 141.385, 31.740 deg which is
RA(J2000) = 09h 25m 32.5s
Dec(J2000) = +31d 44' 23.7"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 80%.
The mask-weighted light curve shows a roughly symetric peak starting
at ~T-15 sec, peaking at ~T+5 sec, and ending at ~T+30 sec.
T90 (15-350 keV) is 26.0 +- 8 sec (estimated error including systematics).
The time-averaged spectrum from T-12.6 to T+25.6 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.60 +- 0.25. The fluence in the 15-150 keV band is 4.0 +- 0.7 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+8.12 sec in the 15-150 keV band
is 0.4 +- 0.1 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/411248/BA/
GCN Circular 10370
Subject
GRB 100205A: Swift UVOT upper limits
Date
2010-02-05T17:37:38Z (17 years ago)
From
Erik Hoversten at Swift/Penn State <hoversten@astro.psu.edu>
E. A. Hoversten (PSU) and J. L. Racusin (NASA/GSFC) report on behalf
of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 100205A
177s after the BAT trigger (Racusin et al., GCN 10361). We do not
detect any source at the enhanced Swift XRT position (Racusin et al.,
GCN 10361) nor at the position of the Gemini-North K-band detection
(Tanvir et al., GCN 10366). UVOT magnitude 3-sigma upper limits are
reported in the following table:
Filter T_start T_stop Exp(s) Mag (3-sigma upper limit)
-------------------------------------------------------------
white 177 327 147 > 20.76
white 177 1533 392 > 21.31
v 665 1580 94 > 18.84
b 763 1162 38 > 19.25
u 335 1311 265 > 20.08
The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight of E_(B-V) = 0.02 mag
(Schlegel et al. 1998). All photometry is on the UVOT photometric
system described in Poole et al. (2008, MNRAS, 383, 627).
GCN Circular 10369
Subject
GRB 100205A: Swift XRT refined analysis
Date
2010-02-05T16:47:28Z (17 years ago)
From
Rhaana Starling at U of Leicester <rlcs1@star.le.ac.uk>
R.L.C. Starling (U Leicester) and J.L. Racusin (NASA/GSFC) report on
behalf of the Swift-XRT team:
We have analysed 1.5 ks of XRT data for GRB 100205A
(trigger=411248, Racusin et al. GCN Circ. 10361), from 157 s to 4.95 ks
after the BAT trigger. The data comprise 11 s of Windowed Timing (WT)
mode settling data and the remainder is in Photon Counting (PC) mode.
At this point Swift coverage of the source stopped due to thermal
constraints, but further observations are now underway.
The enhanced XRT position is given in Evans et al. GCN Circ. 10367.
The light curve can be fit with a doubly broken power law. The difference
between the initial WT mode settling data and the first PC data suggest
a steep initial decay of alpha~9.5. This power law decay breaks at ~180 s
to a plateau with alpha~-0.05, which breaks at 330 +140/-60 s to a decay
of alpha = 2.5 +0.4/-0.3.
The time-averaged PC mode spectrum can be fit with an absorbed power law
of photon index Gamma = 2.2 +/-0.3, and absorption column
N_H (intrinsic at z=0) = (7 +6/-5) x 10^20 cm^-2 in excess of the Galactic
column of 1.65 x 10^20 cm^-2 (Kalberla et al. 2005).
The observed (unabsorbed) 0.3-10 keV flux is (9.0 +1.6/-2.0) x 10^-12 (1.2
x 10^-11) erg cm^-2 s^-1.
The observed (unabsorbed) counts to flux conversion is 3.7 x 10^-11 (4.9 x
10^-11) erg cm^-2 ct^-1.
If the light curve continues to decay with alpha = 2.5 the predicted count
rate at T+24h is 1 x 10^-6 ct s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00411248.
This circular is an official product of the Swift-XRT team.
GCN Circular 10367
Subject
GRB 100205A: Enhanced Swift-XRT position
Date
2010-02-05T14:00:10Z (17 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1394 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 100205A, 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 = 141.38751, +31.74050 which is equivalent
to:
RA (J2000): 09h 25m 33.00s
Dec (J2000): +31d 44' 25.8"
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 10366
Subject
GRB 100205A Gemini-North IR afterglow candidate
Date
2010-02-05T12:24:45Z (17 years ago)
From
Nial Tanvir at IofA U.Cambridge <nrt@ast.cam.ac.uk>
N. R. Tanvir (U. Leicester), A. J. Levan (U. Warwick),
A. Cucchiara & D. Fox (PSU), B. E. Cobb (UC Berkeley),
R. Mason (Gemini) report on behalf of a larger collaboration:
We observed the field of GRB 100205A (Racusin et al. GCN 10361)
with Gemini-North/NIRI, beginning at 06:55 UT (approx 2.6 hr post burst).
In a deep K-band integration we detect a point source within
the enhanced XRT error circle, at position (accuracy ~0.5 arcsec):
RA(2000) = 09 25 33.02
dec(2000)= +31 44 25.0
The approximate magnitude (calibrated against two faint 2MASS stars
in the field) is K~20.2. The source is also marginally detected
in both J and H.
Further analysis is ongoing.
GCN Circular 10365
Subject
GRB 100205A: Gemini-South Observations
Date
2010-02-05T08:13:43Z (17 years ago)
From
Bethany Cobb at UC Berkeley <bcobb@astro.berkeley.edu>
B. E. Cobb, S. B. Cenko, J. S. Bloom (UC Berkeley) report on behalf of a
larger collaboration:
We have imaged the field of GRB 100205A (Racusin et al., GCN 10361) with
the Gemini Multi-Object Spectrograph (GMOS) on the 8 m Gemini South
telescope beginning at 05:48 UT on 05 February 2010 (~ 40 minutes after
the burst trigger time). Observations were conducted in the r' filter for
a total of 600 seconds.
We find no new point sources at the location of the X-ray afterglow
(Racusin et al., GCN 10361). The preliminary limiting magnitude of our
image is r' >~ 23.4 mag for isolated point sources (assuming the SDSS
value of r = 17.76 for the object at RA: 09:25:28.956, Dec: +31:44:20.61).
GCN Circular 10364
Subject
GRB 100205A: Super-LOTIS early observations
Date
2010-02-05T06:20:25Z (17 years ago)
From
Adria C. Updike at Clemson U <aupdike@clemson.edu>
Adria C. Updike (Clemson University), G. Grant Williams (MMTO), Peter A.
Milne (Steward Observatory), and Dieter H. Hartmann (Clemson University)
report:
We observed the field of GRB 100205A (Racusin et al., GCN 10361) with the
0.6m Super-LOTIS telescope located at KPNO under poor conditions.
Observations began 110 seconds after the trigger and continued for 7
minutes before we were forced to close due to humidity. In 270 seconds of
stacked V-band exposures, we detect no new sources in the XRT error circle
down to a limiting magnitude V > 18 (upon comparison to the NOMAD
catalog), which is consistent with the NOT observations (Malesani et al.,
GCN 10362).
GCN Circular 10362
Subject
GRB 100205A: NOT optical observations
Date
2010-02-05T06:01:21Z (17 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@dark-cosmology.dk>
D. Malesani (DARK/NBI), D. Xu (WIS and DARK/NBI), J. P. U. Fynbo
(DARK/NBI), P. Jakobsson (Univ. Iceland), N. R. Tanvir (Univ.
Leicester), J. Lindberg (NOT and Univ. Copenhagen), report on behalf of
a larger collaboration:
We observed the field of GRB 100205A (Racusin et al., GCN 10361) with
the NOT equipped with ALFOSC. Observations were carried out in the R and
I bands, starting at 4:58 and 5:16 UT, that is 39 and 58 min after the
GRB, respectively.
Within the XRT error circle, we do not detect any new source down to
limiting magnitudes R > 23.7 and I > 23.2 (assuming R=17.3 and I = 16.8
for the object at RA = 09:25:28.94, Dec = +31:44:20.8).
We encourage NIR observations.
GCN Circular 10361
Subject
GRB 100205A: Swift detection of a burst
Date
2010-02-05T04:34:16Z (17 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
J. L. Racusin (NASA/GSFC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
D. N. Burrows (PSU), P. A. Evans (U Leicester), E. A. Hoversten (PSU),
J. A. Kennea (PSU), C. B. Markwardt (CRESST/GSFC/UMD),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
D. M. Palmer (LANL), M. H. Siegel (PSU),
M. Stamatikos (OSU/NASA/GSFC), R. L. C. Starling (U Leicester),
T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the
Swift Team:
At 04:18:43 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100205A (trigger=411248). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA 141.406d, Dec +31.739d, which is
RA(J2000) = 09h 25m 37s
Dec(J2000) = +31d 44' 22"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single-peaked
structure with a duration of about 30 sec. The peak count rate
was ~800 counts/sec (15-350 keV), at ~8 sec after the trigger.
The XRT began observing the field at 04:21:38.0 UT, 174.9 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 141.3874, 31.7405 which
is equivalent to:
RA(J2000) = 09h 25m 32.99s
Dec(J2000) = +31d 44' 25.8"
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This
location is 57 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.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
1.65e+20 cm^-2 (Kalberla et al. 2005).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 177 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
0.02.
Burst Advocate for this burst is J. L. Racusin (judith.racusin AT 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.)