////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  8687
SUBJECT: GRB 081221: Swift detection of a burst
DATE:    08/12/21 16:42:05 GMT
FROM:    David Burrows at PSU/Swift  <dxb15@psu.edu>

E. A. Hoversten (PSU), W. H. Baumgartner (GSFC/UMBC),
D. N. Burrows (PSU), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC),
J. A. Kennea (PSU), V. Mangano (INAF-IASFPA),
C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),
P. T. O'Brien (U Leicester), D. M. Palmer (LANL),
J. L. Racusin (PSU), P. Romano (INAF-IASFPA),
B. A. Rowlinson (U Leicester), M. C. Stroh (PSU),
G. Tagliaferri (INAF-OAB), T. N. Ukwatta (GSFC/GWU) and
L. Vetere (PSU) report on behalf of the Swift Team:

At 16:21:11 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 081221 (trigger=337889).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 15.805, -24.526 which is 
   RA(J2000) = 01h 03m 13s
   Dec(J2000) = -24d 31' 32"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed two peaks, at 
T+0 to T+10 seconds and a much larger one at T+15 to T+40 seconds.  
The peak count rate was ~20000 counts/sec (15-350 keV), at 22 sec 
after the trigger. 

The XRT began observing the field at 16:22:20.2 UT, 68.4 seconds after
the BAT trigger. XRT found a bright, fading, uncatalogued X-ray source located
at RA, Dec 15.7934, -24.5484 which is equivalent to:
   RA(J2000)  = 01h 03m 10.41s
   Dec(J2000) = -24d 32' 54.2"
with an uncertainty of 5.0 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. 

The initial flux in the 0.1 s image was 7.36e-08 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White  
filter starting 78 seconds after the BAT trigger, and a finding  
chart exposure of 250 seconds with the u filter starting 290 seconds 
 after the 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 3-sigma upper limit at the XRT position is 
19.9  mag in White, 19.8 mag in u. No correction has been made for 
the expected extinction  corresponding to E(B-V) of 0.02. 

We note that this burst is coincident with a Fermi GBM burst (trigger 251569273). 

Burst Advocate for this burst is E. A. Hoversten (hoversten 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.)

////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  8688
SUBJECT: GRB 081221: NOT observations
DATE:    08/12/21 20:13:16 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

Daniele Malesani, Johan P. U. Fynbo (DARK/NBI), Eric Stempels (Univ. St. 
Andrews), and Tapio Pursimo (NOT), report on behalf of a larger 
collaboration:

We observed the field of GRB 081221 (Hoversten et al., GCN 8687) with 
the NOT equipped with ALFOSC. R-band imaging was carried out (12 min 
exposure) with mean time Dec 21.81 UT (3.14 hr after the GRB). Inside 
the XRT error circle (Hoversten et al., GCN 8687), we detect no source 
down to a limiting magnitude R ~ 23. Further imaging is ongoing.

We note the presence of two faint sources just outside the XRT error 
circle, at approximate coordinates (J2000):

1: RA = 01:03:10.26, Dec = -24:32:47.4, R ~ 22.3
2: RA = 01:03:10.10, Dec = -24:32:58.6, R ~ 23.0

We acknowledge excellent support from the NOT staff.

////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  8689
SUBJECT: GRB 081221: further NOT observations
DATE:    08/12/21 22:12:49 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

Daniele Malesani, Johan P. U. Fynbo (DARK/NBI), Tapio Pursimo (NOT), and 
Eric Stempels (Univ. St. Andrews) report on behalf of a larger 
collaboration:

Further to what reported in GCN 8688, we observed the field of GRB 
081221 (Hoversten et al., GCN 8687) in the I and z filters with the NOT 
equipped with ALFOSC. Exposure times were 18 and 16 min, respectively, 
with mean times Dec 21.844 and Dec 21.863 UT (3.89 and 4.37 hr after the 
GRB, respectively).

Inside the XRT error circle reported by Hoversten et al. (GCN 8687), we 
do not detect any source in either filters. The limiting magnitude is I 
~ 23 assuming I = 17.65 for the USNO star at RA = 01:03:09.59, Dec = 
-24:32:45.0.

We encourage deeper searches of the optical/NIR counterpart of this 
event, which had a bright gamma- and X-ray prompt emission.

////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  8690
SUBJECT: GRB 081221: Enhanced Swift-XRT position
DATE:    08/12/22 03:22:16 GMT
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 4345 s of XRT Photon Counting mode data and 7 UVOT
images for GRB 081221, 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 = 15.7925, -24.5481 which is equivalent
to:

RA (J2000): 01h 03m 10.20s
Dec (J2000): -24d 32' 53.1"

with an uncertainty of 1.4 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
http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an
extension of this method.

This circular was automatically generated, and is an official product of the
Swift-XRT team.

////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  8694
SUBJECT: Konus-Wind observation of GRB 081221
DATE:    08/12/22 11:05:55 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin,
D. Frederiks, P. Oleynik, D. Svinkin, M. Ulanov,
and T. Cline, on behalf of the Konus-Wind team report:

The long GRB 081221 (Hoversten et al., GCN 8687)
triggered Konus-Wind at T0=58874.915 s UT (16:21:14.915).

The burst light curve shows two multipeaked pulses with a total
duration of ~40 s.

As observed by Konus-Wind the burst
had a fluence of (2.28 +/- 0.07)x10^-5 erg/cm2,
and a 256-ms peak flux measured from T0+19.824 s
of (1.75 +/- 0.16)x10^-6 erg/cm2/s
(both in the 20 keV - 1 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+39.424 s) can be fitted (in the 20 keV-1 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.91(-0.14, +0.15),
and Ep = (83 +/- 4) keV (chi2 = 67.4/51 dof).
Fitting by GRB (Band) model yields the same alpha and Ep,
and only an upper limit on the high energy
photon index: beta < -3.48 (chi2 = 67.4/50 dof).

Thus, it is a bright and soft GRB.

All the quoted errors are at the 90% confidence level.

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB081221_T58874/

////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  8698
SUBJECT: GRB 081221: Gemini-N nIR imaging
DATE:    08/12/22 13:49:28 GMT
FROM:    Nial Tanvir at IofA U.Cambridge  <nrt@ast.cam.ac.uk>

N. R. Tanvir (U. Leicester), A. J. Levan (U. Warwick),
K. Wiersema (U. Leicester), A. S. Fruchter, J. Graham (STScI)
report:

We observed the field of GRB 081221 with Gemini-N/NIRI, starting
22 Dec 2008 04:20UT, approximately 12 hours post burst.

Our preliminary analysis reveals a faint point source in the enhanced
XRT error circle (GCN 8690) with magnitude K~20.1 at position:

01:03:10.19
-24:32:52.2

relative to three 2MASS stars in the field.  The source is also
marginally detected in J and H.

We suggest this is most likely the afterglow of GRB 081221, but that
its faintness and red colour (H-K>~2) argue for a dusty sight-line
rather than a high redshift as the explanation for the absence of an
optical detection (GCN 8688 and GCN 8689).

Further analysis is ongoing.

We thank Ricardo Schiavon (Gemini) for his assistance in obtaining
these observations.

////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  8700
SUBJECT: GRB 081221: pseudo-redshift (pz=0.7) from the spectral parameters  of the prompt emission
DATE:    08/12/22 14:02:52 GMT
FROM:    Jean-Luc Atteia at Lab d Astrophys.,OMP,Toulouse  <atteia@ast.obs-mip.fr>

A. Pelangeon and J-L. Atteia (LATT-OMP) report:

We have used the spectral parameters of GRB 081221 provided
by Golenetskii et al. (GCN Circ. 8694) to compute the spectral
pseudo-redshift** of this burst detected by Swift-BAT (Hoversten
et al. GCNC 8687).

We find a pseudo-redshift pz = 0.7 +/- 0.1

** http://cosmos.ast.obs-mip.fr/projet/index.html

////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  8701
SUBJECT: GRB 081221: Swift-XRT Refined Analysis
DATE:    08/12/22 14:26:07 GMT
FROM:    Michael Stroh at PSU/Swift  <stroh@astroh.org>

M.C. Stroh and E. A. Hoversten (PSU) report on behalf of the Swift-XRT  
team:

We have analyzed the first seven orbits of XRT data from GRB 081221  
(Hoversten et al., GCN 8687) beginning 73s after the trigger. The  
Swift-XRT data consists of 803s in Windowed Timing (WT) mode and 5.9ks  
in Photon Counting (PC) mode. The enhanced XRT position for this burst  
was reported by Evans et al. (GCN Circ. 8690).

The X-ray light curve begins with count rates near 10^3 cts/s and has  
an early flare reaching 1130 cts/s at T+103s. Following the flare, the  
light curve can be modeled with a double broken power-law with initial  
decay rate of 5.48 +/- 0.08, initial break time at T+207s, second  
decay rate of 0.68 +/- 0.20, second break time at T+896s, and a final  
decay rate of 1.35 +/- 0.04. If the light curve follows the same  
decline, we predict count rates at T+24hr and T+48hr to be 1.6e-2 and  
6.4e-3 respectively.

The time-averaged WT spectrum can be fit with an absorbed power law  
with photon index Gamma = 1.994 (+/-0.014) and nH of 3.24 (+/- 0.05)  
e21 cm^-2 which is in excess of the Galactic value of 2.03e20 cm^-2  
(Kalberla et al. 2005). The absorbed (unabsorbed) 0.3-10.0 keV flux is  
2.44 (3.86) e-9 ergs/cm^2/s.

The time-averaged PC spectrum can be fit with an absorbed power law  
with photon index Gamma = 2.37 (+/-0.15) and nH of 3.5 (+/-0.5) e21  
cm^-2. The absorbed (unabsorbed) 0.3-10.0 keV flux is 1.04 (2.17) e-11  
ergs/cm^2/s.

This circular is an official product of the Swift-XRT team.

////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  8703
SUBJECT: Swift/UVOT observations of GRB 081221
DATE:    08/12/22 14:56:47 GMT
FROM:    Paul Kuin at MSSL  <npkuin@googlemail.com>

N. P. M. Kuin (MSSL/UCL) and E. A. Hoversten (PSU) report
on behalf of the Swift UVOT team.

The Swift UltraViolet/Optical Telescope (UVOT) began settled
observations of GRB081221 (Swift BAT trigger number 337889,
Hoversten et al., GCN Circ.  8687), on December 21, 2008, at
16:22:29, 78 seconds after the trigger with a white finding chart.

We do not detect any new source at the enhanced XRT position
reported in GCN Circ. 8690 (Evans et al.).

The observed magnitude upper limits for GRB 081221 are given below
for the first observations and the summed exposures in the UVOT
filters:

Filter Tstart(s) Tstop(s)  Exp(s)  Magnitude

wh       78       228     149.8    >20.84  (3-sigma UL)
v       619       639      19.4    >17.89  (3-sigma UL)
b       545       565      19.4    >18.85  (3-sigma UL)
u       290       540     245.8    >20.15  (3-sigma UL)
uvw1    668       688      19.4    >18.10  (3-sigma UL)
uvm2    644       664      19.5    >17.71  (3-sigma UL)
uvw2    595       615      19.4    >18.08  (3-sigma UL)

wh       78      6086     381.0    >21.41  (3-sigma UL)
v        59     34696    2192.4    >20.74  (3-sigma UL)
b       545     41269    1765.2    >21.55  (3-sigma UL)
u       290     40478    3667.7    >21.69  (3-sigma UL)
uvw1    668     39565    3758.4    >21.57  (3-sigma UL)
uvm2    644     45178    3409.4    >21.55  (3-sigma UL)
uvw2    595     33783    2005.6    >21.35  (3-sigma UL)

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 reddening of E(B-V) = 0.021 in the direction of
the burst (Schlegel et al. 1998).

////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  8704
SUBJECT: GRB081221: Fermi GBM observation
DATE:    08/12/22 16:09:29 GMT
FROM:    Colleen A. Wilson at NASA/MSFC/NSSTC  <colleen.wilson@nasa.gov>

Colleen A. Wilson-Hodge (NASA/MSFC) reports on behalf of the Fermi GBM
Team: 

"At 16:21:12.22 UT on 21 December 2008, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 081221 (trigger 251569273 / 081221681),
which was also detected by the SWIFT-BAT and XRT (Hoversten et al. 2008,
GCN 8687).

The on-ground calculated location, using the GBM trigger data, is
RA = 17.2, DEC = -24.8 (J2000 degrees, equivalent to 01 h 09 m, -24 d 50'),
with an uncertainty of less than 1.0 degree (radius, 1-sigma containment,
statistical only; there is additionally a systematic error which is
currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 78 degrees.

The GBM light curve consists of a weak initial peak and a bright second peak
with a duration (T90) of about 40 s (8-1000 keV). The time-averaged spectrum
from T0+0.003 s to T0+38.401 s is adequately fit by a Band function with
Epeak = 77 +/- 1 keV, alpha = -0.42 +/- 0.03, and beta = -2.91 +/- 0.08.
These spectral parameters are consistent with Konus-Wind observations
(Golenetskii et al. 2008, GCN 8694.)

The event fluence (8-1000 keV) in this time interval is
(3.7 +/- 0.1)E-05 erg/cm^2. The 64-msec peak photon flux measured starting
from T0+19.3923 s in the 8-1000 keV band is 33 +/- 9 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."

////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  8708
SUBJECT: GRB 081221, Swift-BAT refined analysis
DATE:    08/12/22 19:27:08 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc@milkyway.gsfc.nasa.gov>

J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
E. A. Hoversten (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),
K. McLean (GSFC/UMD), D. M. Palmer (LANL), 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-239 to T+873 sec from the recent telemetry 
downlink,
we report further analysis of BAT GRB 081221 (trigger #337889)
(Hoversten, et al., GCN Circ.  8687).  The BAT ground-calculated 
position is
RA, Dec = 15.801, -24.542 deg which is
  RA(J2000)  =  01h 03m 12.2s
  Dec(J2000) = -24d 32' 32.8"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 61%.

The mask-weighted light curve shows two main overlapping peaks, the smaller
from about T+0 to T+12 sec and the larger from about T+12 to T+40 sec, with
multiple subsidiary peaks and an extended tail visible to about T+150 sec.
T90 (15-350 keV) is 34 +- 1 sec (estimated error including systematics).

The time-averaged spectrum from T-0.3 to T+112.6 sec is best fit by a power
law with an exponential cutoff.  This fit gives a photon index 1.21 +- 
0.13,
and Epeak of 69.9 +- 3.9 keV (chi squared 37.73 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 1.81 +- 0.03 x 10-05 
erg/cm2
and the 1-sec peak flux measured from T+21.42 sec in the 15-150 keV band is
18.2 +- 0.5 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.86 (chi squared 119.90 for 57 d.o.f.).  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/337889/BA/

////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  8711
SUBJECT: GRB 081221: Probable host galaxy in Keck imaging
DATE:    08/12/23 11:23:47 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley, J. S. Bloom (UC Berkeley), J. Kalirai (STSCI), R. 
Strickler, E. Ramirez-Ruiz (UCSC), and A. A. Miller (UCB) report:

We began a series of deep optical imaging exposures on the field of GRB 
081221 (Hoversten et al., GCN 8687) using the Keck I telescope (+LRIS) 
starting at 2008-12-23 at 5:06 UT.  We acquired 10x330s in g-band and 
10x300s in I-band (simultaneously using the 560 dichroic).

A extended source coincident with the Gemini (Tanvir et al., GCN 8698) 
and Swift XRT (GCN 8690) afterglow positions is clearly detected in our 
g-band stack, which we tentatively identify as the host galaxy.  The 
magnitude within a 1.0" aperture of this object is approximately B~25.4 
(calibrated relative to the USNO star at RA=15.797098, dec=-24.412259, 
B2=19.59).  It is only marginally detected in the I-band imaging, with 
an estimated magnitude of I~24.5, though photometry in this band is 
complicated by blending with a nearby object.

The detection of a host galaxy would be consistent with a low-redshift 
origin (GCN 8698).  Within the significant uncertainties of the 
photometric calibration the color of the galaxy appears typical of 
normal GRB hosts.  Further analysis is planned.

An image of the field is posted to:
http://lyra.berkeley.edu/~dperley/081221/081221hostkeck.png

////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  8719
SUBJECT: GRB 081221: GROND observations
DATE:    08/12/23 20:22:43 GMT
FROM:    Paulo M. J. Afonso at MPE  <pafonso@mpe.mpg.de>

GRB 081221: GROND observations 

P. Afonso, T. Kruehler, J. Greiner, C. Clemens (all MPE Garching) and A.
Updike (Clemson University) report on behalf of the GROND team: 

GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m ESO/MPI
telescope at La Silla Observatory (Chile) imaged the field of GRB 081221
(Swift trigger 337889, Hoversten et al., GCN #8687) on two epochs
simultaneously in g'r'i'z'JHK. This burst was also detected by Konus-Wind
(Golenetskii et al. GCN #8694) and the Fermi GBM (Wilson-Hodge, GCN
#8704). 

The first epoch started on 2008-12-22 at 01:33:08 UT roughly 9 hours after
the trigger and consisted of 16 images of 375s exposure in g'r'i'z' and
480 images of 10s exposure in JHK. An equal amount of images were obtained
during the second epoch in the following night from 01:19:56 UT on, 33
hours after the burst. 

Inside the refined XRT error circle (Stroh & Hoversten, GCN #8701) we
detect in both epochs the object reported by Tanvir et al.(GCN #8698) and
Perley et al. (GCN #8711) in g'r'i', but not in z'JHK. 

No variability between the two epochs is evident, and no other source is
detected inside the XRT error circle. 

Preliminary VEGA magnitudes from the second epoch calibrated against
USNO-B field stars and upper limits are as follows: 

g' = 25.2 +/- 0.3
r' = 24.7 +/- 0.2
i' = 24.4 +/- 0.4
z' > 24.0
J > 21.0
H > 19.8
K > 19.0 

Given the large errors due to image statistics, photometric calibration
and complicated photometry as pointed out by Perley et al. (GCN #8711),
these values are consistent with what is reported in GCNs #8698 and #8711. 

 

////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  8741
SUBJECT: VLA radio observation of GRB 081221
DATE:    08/12/27 20:13:00 GMT
FROM:    Poonam Chandra at U Virginia/NRAO  <pc8s@virginia.edu>

Poonam Chandra (RMC) 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 081221 (GCN 8687) at a frequency of 8.46 GHz on 2008 Dec 27.14
UT. The GRB radio afterglow is undetected at 3-sigma level. However,
there is a 2.5 sigma source (97 +/- 38 uJy) at the Gemini optical
afterglow position reported by Tanvir et al. (GCN 8698).

The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."

////////////////////////////////////////////////////////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  8748
SUBJECT: VLA radio detection of GRB 081221
DATE:    08/12/28 16:10:17 GMT
FROM:    Poonam Chandra at U Virginia/NRAO  <pc8s@virginia.edu>

Poonam Chandra (RMC) and Dale A. Frail (NRAO) report on
behalf of the Caltech-NRAO-Carnegie GRB Collaboration:

"We used the Very Large Array to re-observe the field of view toward
GRB 081221 (GCN 8687) at a frequency of 8.46 GHz on 2008 Dec 28.16
UT for a longer integration. The GRB radio afterglow is clearly
detected at the Gemini optical afterglow position (GCN 8698) with the
flux density of 167 +/- 27 uJy.

The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."