GRB 091208B
GCN Circular 10255
Subject
GRB 091208B: BOOTES-3 optical afterglow
Date
2009-12-08T10:11:30Z (16 years ago)
From
Antonio Deugarte at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (INAF-OAB), A.J. Castro-Tirado,
J. Gorosabel, M. Jelinek (IAA-CSIC), P. Kubanek (IPL UV, IAA-CSIC),
R. Cunniffe, S. Guziy (IAA-CSIC), P. Yock (Auckland Univ.), W.H.
Allen (Vintage Lane Obs.), I. Bond (Massey Univ.), G. Christie
(Stardome Obs.), report on behalf of a larger collaboration, report:
"We have observed the field of GRB091208B (Swift trigger 378559)
using the 0.6m Yock-Allen robotic telescope (BOOTES-3)
located in Bleinheim, New Zealand. Observations began at 09:50:04 UT
(45 sec after the burst).
There is a bright optical counterpart within the XRT error
circle at coordinates (J2000.0 +/- 1"):
R.A.: 01:57:34.13
Dec.: +16:53:23.00
Further observations are ongoing."
[GCN OPS NOTE(11oct09): Per author's request, the time was changed
from "05:50:04" to "09:50:04". Please note that the OPS NOTE was
first set up in 11oct09, but it took me until 29oct2021 to actually
change the time in the body of the text. Thanks to Alex Kann to notice
that the change needed to be completed.]
GCN Circular 10256
Subject
GRB 091208B: Swift detection of a burst with an optical afterglow
Date
2009-12-08T10:13:59Z (16 years ago)
From
Claudio Pagani at PSU/Swift-XRT <pagani@astro.psu.edu>
C. Pagani (PSU), A. P. Beardmore (U Leicester),
P. A. Evans (U Leicester), C. Gronwall (PSU),
S. T. Holland (CRESST/USRA/GSFC), N. P. M. Kuin (MSSL),
C. B. Markwardt (CRESST/GSFC/UMD), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), A. Rowlinson (U Leicester),
M. Stamatikos (OSU/NASA/GSFC), G. Tagliaferri (INAF-OAB) and
L. Vetere (PSU) report on behalf of the Swift Team:
At 09:49:57 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 091208B (trigger=378559). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 29.410, +16.883 which is
RA(J2000) = 01h 57m 39s
Dec(J2000) = +16d 52' 57"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a double-peaked
structure with a duration of about 15 sec. The peak count rate
was ~9100 counts/sec (15-350 keV), at ~8 sec after the trigger.
The XRT began observing the field at 09:51:53.1 UT, 115.2 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 29.3920,
16.8899 which is equivalent to:
RA(J2000) = 01h 57m 34.09s
Dec(J2000) = +16d 53' 23.6"
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This
location is 66 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 in excess of the Galactic value (4.85e+20
cm^-2, Kalberla et al. 2005), with an excess column of 3.3
(+1.52/-1.28) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White
filter starting 119 seconds after the BAT trigger. There is an
afterglow in the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 01:57:34.06 = 29.39193
DEC(J2000) = +16:53:22.7 = 16.88963 with a 90%-confidence
error radius of about 0.6 arc sec. This position is 0.67 arc sec.
from the center of the XRT error circle. The estimated magnitude is
17.9. No correction has been made for the expected extinction
corresponding to E(B-V) of 0.05. There is a bright afterglow
candidate consistent with the XRT position.
Burst Advocate for this burst is C. Pagani (pagani AT astro.psu.edu).
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 10257
Subject
GRB 091208B, RIMOTS optical upper limits
Date
2009-12-08T11:57:37Z (16 years ago)
From
Kazuhiro Noda at Miyazaki U <kaz1206@astro.miyazaki-u.ac.jp>
K.Noda, K.Kono, E.Sonoda, N.Ohmori, H.hayasi,
A.Daikyuji, Y.Nisioka, M.Yamauchi
(University of Miyazaki)
We have observed the field covering the error circle of
GRB GRB091208B (Swift trigger 378559, GCN 10256, C. Pagani et al.)
with the unfiltered CCD camera on the 30-cm telescope
at University of Miyazaki.
The observation was started 09:59:30 UT, about 9.5 min
after the Swift trigger time.
We have compared our data of 30 sec exposures
with the USNO-A2.0 catalog,
There is no new source at the reported position.
(GCN 10255, A. de Ugarte Postigo et al.)
the upper limits are as follows:
--------------------------------------------------------------
Start(UT) End(UT) Num. of frames Limit (mag.)
--------------------------------------------------------------
09:59:30 10:00:00 1 15.9
09:59:30 10:47:23 37 17.3
---------------------------------------------------------------
GCN Circular 10258
Subject
GRB 091208B: MITSuME Okayama Optical Observation
Date
2009-12-08T12:06:40Z (16 years ago)
From
Michitoshi Yoshida at Okayama Astrophysical Obs <yoshida@oao.nao.ac.jp>
M. Yoshida, D. Kuroda, K. Yanagisawa, Y. Shimizu, S. Nagayama,
H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:
We observed the field of GRB 091208B (Pagani et al., GCN 10256)
with the optical three color (g', Rc and Ic) CCD camera attached
to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started at 09:57:03 2009-12-08 UT, 426s after the
trigger. We detected the optical afterglow previously reported
by de Ugarte Postigo et al. (GCN 10255) and Pagani et al. (GCN
10256) in all the three bands.
The preliminary photometry results of the OT are listed below. We
used GSC2.3 catalog for flux calibration.
#PDAY MID-UT T-EXP g' Rc Ic
------------------------------------------------------------------
0.00855 10:02:17 540.0 18.4 $B!^(B 0.2 17.6 $B!^(B 0.1 17.0 $B!^(B 0.2
0.01615 10:13:14 540.0 18.5 $B!^(B 0.2 18.1 $B!^(B 0.2 17.4 $B!^(B 0.2
------------------------------------------------------------------
GCN Circular 10259
Subject
GRB 091208B: Enhanced Swift-XRT position
Date
2009-12-08T12:50:30Z (16 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 466 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 091208B, 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 = 29.39223, +16.88965 which is equivalent
to:
RA (J2000): 01h 57m 34.13s
Dec (J2000): +16d 53' 22.7"
with an uncertainty of 1.8 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 10260
Subject
GRB 091208B: MITSuME Akeno Optical Observation
Date
2009-12-08T13:34:54Z (16 years ago)
From
Nobuyuki Kawai at Tokyo Tech <nkawai@hp.phys.titech.ac.jp>
H. Nakajima, Y. Yatsu, Y.A. Mori, A. Endo, T. Shimokawabe, and
N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 091208B (Pagani et al., GCN 10256)
with the optical three color (g', Rc and Ic) CCD camera attached
to the MITSuME 50cm telescope at Akeno, Japan.
The observation started at 2009-12-08 09:50:45 UT, 48s after the
trigger. We detected the optical afterglow (de Ugarte Postigo et al.
GCN 10255, Pagani et al. GCN 10256, Yoshida et al. GCN 10258)
in all the three bands.
The preliminary photometry results of the OT are listed below. We
used GSC2.3 catalog for flux calibration.
MID-UT T-EXP g' Rc Ic
------------------------------------------------------------------
09:51:15 60.0 17.2 $B!^(B 0.2 16.1 $B!^(B 0.1 15.5 $B!^(B 0.1
------------------------------------------------------------------
GCN Circular 10262
Subject
GRB 091208B: Faulkes Telescope North and South Optical Afterglow
Date
2009-12-08T13:52:33Z (16 years ago)
From
Zach Cano at ARI/John Moores Liverpool <zec@astro.livjm.ac.uk>
Z. Cano, A. Melandri, C.G. Mundell (Liverpool JMU), A. Gomboc (U.
Ljubljana), D. Bersier, N.R. Clay, S. Kobayashi, C.J. Mottram, R.J. Smith,
I.A. Steele (Liverpool JMU), C. Guidorzi (U. Ferrara) report on behalf of
a large collaboration:
The 2-m Faulkes Telescopes North and South robotically followed up
GRB091208B (SWIFT trigger 378559; Pagani et al. GCN 10256) beginning 1.78
min after the GRB trigger time. We detect the optical afterglow in BRi'
filters at the location reported by de Ugarte Postigo et al. (GCN 10255)
and Pagani et al. (GCN 10256).
We derive the following preliminary magnitudes wrt USNOB1:
Filter Mag Merr T-To (s)
-------------------------------------------
R 17.75 0.02 572
R 18.48 0.03 1656
I 17.51 0.05 1036
I 18.34 0.04 3749
From our observations we derive a power-law decay constant of ~ 0.6 for
both filters.
We have not corrected our magnitudes for the small amount of foreground
reddening along the line of sight (E(B-V) = 0.05, corresponding to Av =
0.17 (Schlegel et al. 1998)).
Observations and analysis are ongoing.
This message may be cited.
GCN Circular 10263
Subject
GRB 091208B: Gemini-North redshift
Date
2009-12-08T15:09:46Z (16 years ago)
From
Klaas Wiersema at U of Leicester <kw113@star.le.ac.uk>
K. Wiersema, N. R. Tanvir (U. Leicester), A. Cucchiara (PSU),
A. J. Levan (U. Warwick) & D. Fox (PSU) report:
We observed the afterglow of GRB 091208B (Pagani et al. GCN 10256;
de Ugarte Postigo et al. GCN 10255) with the GMOS-N spectrograph on Gemini
North, beginning at 11:17 UT on December 8. We use the R400 grism.
The resulting spectrum covers the wavelength range 4000-8400 A and shows
clear absorption lines of the MgII doublet (2796,2803), MgI (2853), FeI
(2967), FeII (2586,2600) and MnII (2576,2594,2606) at a common redshift
of z = 1.063.
We thank the Gemini-N staff, in particular K. Chiboucas, for
performing this observation.
GCN Circular 10265
Subject
GRB 091208B, Swift-BAT refined analysis
Date
2009-12-08T15:59:30Z (16 years ago)
From
Jay R. Cummings at NASA/GSFC/Swift <james.r.cummings@nasa.gov>
W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC),
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), C. Pagani (PSU), A. M. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(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 091208B (trigger
#378559) (Pagani, et al., GCN Circ. 10256). The BAT ground-
calculated position is RA, Dec = 29.411, 16.881 deg which is
RA(J2000) = 01h 57m 38.5s
Dec(J2000) = +16d 52' 50.7"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 10%.
The mask-weighted light curve shows two separated FRED peaks. The first
at T0 was weaker and softer than the second at T+8 sec.
T90 (15-350 keV) is 14.9 +- 3.7 sec (estimated error including
systematics).
The time-averaged spectrum from T-0.2 to T+22.3 sec is best fit by a
simple power-law model. The power law index of the time-averaged
spectrum is 1.74 +- 0.11. The fluence in the 15-150 keV band was
3.3 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from
T+8.1 sec in the 15-150 keV band was 15.2 +- 1.0 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/378559/BA/
GCN Circular 10266
Subject
GRB 091208B: Fermi GBM observation
Date
2009-12-08T17:42:47Z (16 years ago)
From
Sheila McBreen at MPE <smcbreen@mpe.mpg.de>
S. McBreen (UCD/MPE) reports on behalf of
the Fermi GBM Team:
"At 09:49:57.96 UT on 08 December 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 091208B (trigger 281958599 / 091208410)
which was also detected by the Swift-BAT (Pagani et al. 2009, GCN 10256).
The GBM on-ground location is consistent with the Swift position.
This burst was also independently detected by INTEGRAL SPI-ACS.
The angle from the Fermi LAT boresight is 56 degrees.
Moreover, this burst was bright enough to result in
a Fermi spacecraft repointing maneuver.
The GBM light curve consists of two pulses
with a duration (T90) of about 15 s (8-1000 keV).
The time-averaged spectrum from T0-0.128 s to T0+14.592 s is
well fit by a power law function with an exponential
high energy cutoff. The power law index is -1.48 (+0.05/-0.05) and
the cutoff energy, parameterized as Epeak, is 144.20 (+18.00/-13.90) keV
(CSTAT 829 for 604 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(5.8 +/- 0.2)E-06 erg/cm^2. The 0.128 sec peak photon flux measured
starting from T0+8.45 s in the 8-1000 keV band is 32.4 +/- 1.1 ph/s/cm^2.
A Band function fits the spectrum equally well (CSTAT 827 for 603 d.o.f.)
with Epeak= 124.00 (+20.10/-19.40) keV, alpha = -1.44 (+0.07/-0.06)
and beta = -2.32 (+0.19/-0.47).
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 10267
Subject
GRB091208B: Swift/UVOT refined analysis
Date
2009-12-08T18:00:07Z (16 years ago)
From
Massimiliano de Pasquale at MSSL-UCL <mdp@mssl.ucl.ac.uk>
M. De Pasquale (MSSL/UCL) and C. Pagani (PSU) report on
behalf of the Swift UVOT team.
The Swift UltraViolet/Optical Telescope (UVOT) began settled
observations of the GRB 091208B (Swift BAT trigger number 378559;
Pagani et al. GCN Circ. 10256) 119 s after the BAT trigger
with an exposure in the UVOT white filter.
A new optical source is found at position
RA, Dec = 29.39204, 16.88967, corresponding to
RA (J2000) = 01 57 34.09
Dec (J2000) = +16 53 22.82
This is within 0.6 arseconds from the XRT enhanced position
(Osborne et al., GCN Circ. 10259) and consistent with it.
The detection is in all 3 filters UVOT used at early epoch.
The initial magnitudes are given below.
Filter Time(s) Mag Err
wh 119-269 17.92 0.04
b 588-605 18.38 0.29
u 333-583 18.63 0.09
We caution that data analysis is slightly complicated by the
presence of a dim source 3 arcsecond away from the afterglow.
The values quoted above are on the UVOT Photometric System
(Poole et al., 2008, MNRAS 383,627). They are not corrected for
the expected Galactic extinction, corresponding to a reddening
of E(B-V)=0.05.
GCN Circular 10268
Subject
GRB 091208B: Swift-XRT refined analysis
Date
2009-12-08T20:50:26Z (16 years ago)
From
Claudio Pagani at PSU/Swift-XRT <pagani@astro.psu.edu>
C. Pagani (PSU) and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team:
We have analysed 3.6 ks of XRT data for GRB 091208B (Pagani et al. GCN
Circ. 10256), from 132 s to 12.2 ks after the BAT trigger. The data are
entirely in Photon Counting (PC) mode. The enhanced XRT position for this
burst was given by Osborne et al. (GCN. Circ 10259).
The light curve presents bumps and mini-flares and can be modelled with a
power-law decay with a decay index of alpha=0.73 (+0.04, -0.05).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.32 (+0.18, -0.16). The
best-fitting absorption column is 2.9 (+/-0.5) x 10^21 cm^-2, in excess of
the Galactic value of 4.8 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 3.7 x 10^-11 (7.2 x 10^-11) erg cm^-2 count^-1.
If the light curve continues to decay with a power-law decay index of 0.73,
the count rate at T+24 hours will be 0.034 count s^-1, corresponding to an
observed (unabsorbed) 0.3-10 keV flux of 1.3 x 10^-12 (2.5 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/00378559.
This circular is an official product of the Swift-XRT team.
GCN Circular 10269
Subject
GRB091208B: NOT optical observations
Date
2009-12-08T22:10:36Z (16 years ago)
From
Dong Xu at DARK,NBI <dong@astro.ku.dk>
D. Xu (WIS, DARK/NBI), G. Leloudas, D. Malesani (DARK/NBI), P. Jakobsson
(Univ. of Iceland), J. Lindberg, J. Andersen (NOT) report on behalf of a
larger collaboration:
We observed the field of GRB091208B (Pagani et al. GCN 10256; de Ugarte
Postigo et al. GCN 10255) at the Nordic Optical Telescope equipped with
ALFOSC. The 2x300s frames were obtained starting at 20:46:43 UT on Dec.
08th, 10.9878 hr after the burst trigger.
The magnitude of the afterglow is R~20.9 with respect to stars in the
USNO B1 catalog. Comparison with the measurement in Cano et al. (GCN
10262) indicates a general decay slope of ~0.6-~0.7 in the R band.
[GCN OPS NOTE(22dec09): Per author's request, the date in the 2nd sentence
was changed ""from Nov 28" to "Dec 8".]
GCN Circular 10271
Subject
GRB 091208B: GROND observations
Date
2009-12-09T05:13:59Z (16 years ago)
From
Andrea Rossi at TLS Tautenburg <rossi@tls-tautenburg.de>
Adria Updike (Clemson University), Andrea Rossi (Tautenburg Obs.) and
Jochen Greiner (MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 091208B (Swift trigger 378559, Pagani et al.,
GCN #10256) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,
PASP 120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla
Observatory (Chile).
First observations started at 01:07 UT on Dec 09, 15h17m after the GRB
trigger,
for a total integration time of 7.7 min in g'r'i'z' and 8min in JHK.
For the afterglow reported by Pagani et al. and
de Ugarte Postigo et al. (GCN #10255) we estimate the
following preliminary magnitudes (in the AB system):
g' = 22.64 +- 0.15
r' = 21.88 +- 0.14
i' = 21.65 +- 0.17
z' = 21.35 +- 0.17
J = 20.61 +- 0.10
H = 20.5 +- 0.3
K analysis on going
These magnitudes are in agreement with a afterglow at redshift z<3.5.
After correction for the different filter and magnitude system,
a comparison with other observation (Xu et al.,GCN #10269 and Cano et
al., GCN #10262) confirms that the afterglow is decaying with the slope
of 0.6-0.7 reported by Xu et al. .
Given magnitudes are calibrated against GROND zeropoints as well as 2MASS
field stars. The errors take in account zero point uncertainties.
Magnitudes are not corrected for the expected Galactic foreground
extinction corresponding to a reddening of E_(B-V)=0.05 mag in the
direction of the burst (Schlegel et al. 1998).
GCN Circular 10272
Subject
GRB 091208B: Keck HIRES redshift confirmation
Date
2009-12-09T06:11:31Z (16 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
D. A. Perley (UC Berkeley), J. X. Prochaska (UCSC), P. Kalas, A. Howard,
M. Fitzgerald, G. Marcy, and J. Graham (UCB) report:
Starting at 10:58:17 UT on December 8 we initiated a single 1200 second
exposure of the afterglow of GRB 091208B (GCN 12055, de Ugarte Postigo
et al.; GCN 10256, Pagani et al.) with HIRES-r on the 10m Keck I
telescope. Consistent with the result of Wiersema et al. (GCN 10263),
we detect absorption lines from MgII and MnII at a redshift of
z=1.0633+/-0.0003. Additionally, we detect fine-structure transitions
of FeII confirming that this is the redshift of the GRB.
GCN Circular 10273
Subject
GRB 091208B: optical observations
Date
2009-12-09T12:32:39Z (16 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
M.Andreev, A.Sergeev, N.Parakhin, N.Karpov (Terskol Branch of Institute of
Astronomy), Yu. Kuznietsova (Main Astronomical Observatory NASU), V.Petkov
(Baksan Neutrino Observatory INR) and A. Pozanenko (IKI) on behalf of larger
GRB follow up collaboration report:
We observed the field of the Swift GRB 091208B (Pagani et al. GCN 10256)
with the Z-600 telescope of Mt.Terskol observatory in R-filter on Dec. 08
starting at (UT) 15:40. In combined images we detect the optical afterglow
(Ugarte Postigo et al. GCN 10255, Pagani et al. GCN 10256).
Preliminary photometry is based on the USNO-B1.0 reference star
#1069-0020318 assuming R2=17.47:
UT Filter, Exposure, mag. err.
(mid) (s)
16:10 R 30x120 20.15 0.25
18:11 R 30x120 20.60 0.25
19:11 R 30x120 20.9 0.3
20:19 R 30x120 21.0 0.3
Combined image can be found in
http://grb.rssi.ru/GRB091208B/GRB091208B_Terskol600_R.jpg
GCN Circular 10275
Subject
GRB 091208B: GAO 150cm telescope Optical Observation
Date
2009-12-10T08:51:42Z (15 years ago)
From
Kenzo Kinugasa at Gunma Astro. Obs/Japan <kinugasa@astron.pref.gunma.jp>
K. Kinugasa, S. Honda, H. Takahashi, H. Taguchi, O. Hashimoto
(Gunma Astronomical Observatory) report:
The position of GRB 091208B (Pagani et al., GCN 10256) was observed
with the 150 cm telescope of Gunma Astronomical Observatory.
Starting at 10:21:09 UT on Dec.8 ( 0.52 hours after the trigger),
both Rc and Ic frames were acquired for sets of 3 x 2-min and
5 x 5-min exposures.
We detected the optical counterpart (e.g., de Ugarte Postigo et al.,
GCN 10255; Yoshida et al. GCN 10258) in all frames. We estimated the
Rc and Ic magnitudes relative to USNO-B1.0 R2 and I magnitudes,
respectively.
mid-UT T0+(d) exp mag.
-----------------------------------------------------
10:50:45 0.01796 3x2min, 5x3min Rc=18.8+-0.1
11:07:20 0.02273 3x2min, 5x3min Ic=18.4+-0.1
-----------------------------------------------------
The R magnitude is consistent with the fading trend of a power-law
slope of ~0.7 from the other optical observations (e.g. Cano et al.
GCN 10262; Xu et al. GCN 10269; Nakajima et al. GCN 10260).
GCN Circular 10279
Subject
GRB 091208B: Xinglong TNT optical observation
Date
2009-12-13T08:53:10Z (15 years ago)
From
L.P. Xin at NAOC <xlp@bao.ac.cn>
L.P. Xin, S. B, Qian, Y.L. Qiu, J. Wang,
J.Y. Wei, W. K. Zheng, J. S. Deng, and J. Y. Hu
on behalf of EAFON report:
We observed the optical afterglow of GRB 091208B
(Pagani et al. GCN 10256) with Xinglong TNT telescope
from Nov. 8th, 10:12:31.6(UT), 23 min after the burst.
The optical counterpart was clearly detected in our images.
The brightness was estimated to be about R~18.5 relative to
the USNO-B1.0 R2 mag, at the meam time of 30 min
after the burst.
This message may be cited.
for more information about Xinglong GRBs Follow-up
observations, please visit the web-site
http://www.xinglong-naoc.org/grb/