GRB 080212

E. Berger (Princeton) reports:

"Inspection of DSS and 2MASS images reveals an extended object coincident 
with the XRT position of GRB 080212 (trigger 303105).  The coordinates are 
(J2000):

 	RA = 15:24:35.19
 	DEC= -22:44:29.0

This indicates that the burst is likely at low redshift."

H. Ziaeepour (UCL-MSSL), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
P. J. Brown (PSU), D. N. Burrows (PSU), M. M. Chester (PSU),
J. R. Cummings (NASA/UMBC), G. Cusumano (INAF-IASFPA),
M. De Pasquale (UCL-MSSL), O. Godet (U Leicester),
C. Guidorzi (INAF-OAB), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA),
V. Mangano (INAF-IASFPA), J. Mao (INAF-OAB),
C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),
P. T. O'Brien (U Leicester), C. Pagani (PSU),
K. L. Page (U Leicester), D. M. Palmer (LANL),
D. Perez (U Leicester), P. Romano (INAF-IASFPA),
T. Sakamoto (NASA/UMBC), G. Sato (GSFC/ISAS),
B. Sbarufatti (INAF-IASFPA), M. Stamatikos (NASA/ORAU),
R. L. C. Starling (U Leicester), G. Tagliaferri (INAF-OAB),
E. Troja (U Leicester/INAF-IASFPa), D. E. Vanden Berk (PSU) and
L. Vetere (PSU) report on behalf of the Swift Team:

At 17:34:33 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 080212 (trigger=303105).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 231.107, -22.752 which is 
   RA(J2000) = 15h 24m 26s
   Dec(J2000) = -22d 45' 06"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single peak
with a duration of about 20 sec.  The peak count rate was ~1000 
counts/sec (15-350 keV), at ~0 sec after the trigger.  There may be a
precursor at T-60 sec. 

The XRT began observing the field at 17:36:19 UT, 106 seconds after the
BAT trigger. XRT found a bright, fading X-ray source
located at RA, Dec 231.1466, -22.7410 which is
   RA(J2000)  =  15h 24m 35.1s
   Dec(J2000) = -22d 44' 27.5"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). 
This location is 137 arcseconds from the BAT on-board position,
within the BAT error circle. The initial flux in the 2.5s image
was 6.9e-09 erg/cm2/s (0.2-10 keV). 

UVOT took a finding chart exposure of 400 seconds with the V filter
starting 109 seconds after the BAT trigger. No afterglow candidate
has been found in the initial data products. There is a object in the
DSS image inside the XRT error circle which is also detected by UVOT
with a magnitude of 17.7. The 2.7'x2.7' sub-image covers 100% of the
XRT error circle. The 8'x8' region for the list of sources generated
on-board covers 100% of the XRT error circle. No correction has been
made for the expected extinction of about 0.5 magnitudes. 

Burst Advocate for this burst is H. Ziaeepour (hz AT mssl.ucl.ac.uk). 
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.)

K.L. Page, D. Perez (U Leicester) and H. Ziaeepour (UCL-MSSL) report on 
behalf of the Swift-XRT team:

We have analysed the first three orbits of data obtained for GRB 080212 
(Ziaeepour et al., GCN Circ. 7296
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 ). Most of the initial orbit of data were 
collected in Windowed Timing (WT mode), and show strong flaring activity. 
Using the second two orbits [Photon Counting (PC) mode data; 5.2 ks of 
exposure time], we obtained a refined position of RA, Dec (J2000) = 
231.1468, -22.7420, which is equivalent to

RA(J2000) =   15 24 35.24
Dec(J2000) = -22 44 31.0

with an estimated uncertainty of 3.6 arcsec. This is 3.7 arcsec from the 
onboard XRT position (GCN Circ. 7296
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 ).

Following the flares in the first orbit of data, the X-ray light-curve can 
be fitted with a power-law, with the decay slope, alpha = 0.8 +/- 0.1.

There is strong spectral evolution during the flaring WT data. A spectrum 
formed from the PC mode data can be modelled with an absorbed power-law, 
with Gamma = 2.3 +/- 0.2 and NH = (2.1 +/- 0.4)e21 cm^-2, significantly in 
excess of the Galactic value of 7.26e20 cm^-2. The 0.3-10 keV observed 
(unabsorbed) flux during this time (~3.5 - 12 ks after the trigger) is 
8.4e-12 (1.5e-11) erg cm^-2 s^-1.

If the light-curve continues to decay at this rate, the predicted count 
rate at 24 hours will be 0.024 count s^-1. Using the PC data, a counts to 
flux conversion of 4.0e-11 erg cm^-2 count^-1 can be estimated, implying 
the predicted flux at 24 hours would be 9.6e-13 erg cm^-2 s^-1.

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

M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 399 s of overlapping XRT Photon Counting mode and UVOT
V-band data for GRB 080212, 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 = 231.14749, -22.74154 which is equivalent
to:

RA (J2000): 15h 24m 35.40s
Dec (J2000): -22d 44' 29.5"

with an uncertainty of 2.0 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, astro-ph/0708.0986
http://www.swift.ac.uk/xrt_positions/Goad.pdf).

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

A. S�nchez Caso (Gualba Obs., Barcelona), M. Jel�nek, A. J.
Castro-Tirado, J. Gorosabel (IAA-CSIC, Granada) and D. P�rez-Ram�rez (U.
Leicester), on behalf of a larger collaboration, report:

"Following the detection of GRB 080212 by Swift/BAT (Ziaeepour et al.,
GCN Circ. 7296
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 ), we have obtained VRI-band images with the 0.4m Gualba
Obs. telescope under non-optimal conditions, starting on Feb 13.263 UT
(i.e. 13.0 hr after the trigger). At the Swift/XRT position given by
Page et al. (GCN Circ. 7299
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 ) we only see the DSS2 galaxy pointed out by
Berger (GCN Circ. 7294
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 ). The limiting magnitude of our images is R = 18.
Much deeper optical/nIR observations are encouraged."

This message can be quoted.

P. D'Avanzo, L.A. Antonelli, S. Covino, D. Fugazza, L.  Calzoletti, S. 
Campana, G.  Chincarini, M.L. Conciatore, S. Cutini, V. D'Elia, F. 
Dalessio, F.  Fiore, P. Goldoni, D. Guetta,  C. Guidorzi, G.L. Israel, 
N. Masetti, A. Melandri, E. Meurs, L. Nicastro, E. Palazzi, E. Pian, S. 
Piranomonte, L.  Stella, G.  Stratta, G. Tagliaferri, G. Tosti, V.Testa, 
S.D. Vergani,  F. Vitali report on behalf of the REM team:

The robotic 60-cm REM telescope located at La Silla (Chile) observed 
automatically the field of the GRB 080212 (Ziaeepour et al., GCN 7296
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 ). 
A preliminary analysis of the first set of H-band exposures does reveal 
the presence of an object with H ~ 15.2 inside the XRT error box (Goad 
et al., GCN 7300
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 ) at the following coordinates (J2000):

R.A. = 15:24:35.49
Dec. = -22:44:29.0

with an uncertainty of 0.3". This position lies about 3.2" (East 
direction) far from the position of the DSS galaxy (Berger, GCN 7294
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 ). 
This object could thus be the NIR afterglow of GRB 080212. The 3sigma 
upper limit of our image is H > 15.7 (calibrated  against the 2MASS 
catalog).

Further analysis is in progress.

A. Kuepcue Yoldas, A. Yoldas, J. Greiner, T. Kruehler (all MPE Garching),
A. Rossi (Tautenburg Obs) report for the GROND team:

We observed the field of GRB 080212 (trigger 303105) detected by Swift/BAT 
(Ziaeepour et al. 2008, GCN 7296
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 ) simultaneously in grizJHK with GROND 
(Greiner et al. 2008, astro-ph/0801.4801), mounted at the 2.2m MPI/ESO 
telescope at La Silla (Chile). Observations started on Feb. 13, at 05:30 UT 
(12 hrs after the GRB), when the GRB location was becoming visible at 
20 degrees above horizon.

We detect a new source in all filters, suggesting the Ly-break being below the 
g'-band (and thus z<3.5). It is clearly separated from the galaxy mentioned by 
Berger et al. (2008, GCN 7294
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 ). The position is

  RA (2000.0) = 15:24:35.4 
  Decl (2000.0) = -22:44:30

At 6:36 UT we measure i'=22.6 mag. No statement about variability can be 
made at this stage. GROND observations are continuing.

E. Berger (Princeton) reports:

"A 900-sec spectrum obtained with Gemini-South/GMOS reveals that the 
object near the XRT position is a late-K star and not a galaxy as 
initially indicated in GCN 7294
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 .

In a 60 sec r-band acquisition image we find a faint source coincident 
with the XRT position at:
 	RA = 15:24:35.4
 	DEC = -22:44:30	(J2000)

This object is consistent with the positions reoprted in GCNs 7302
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  and 
7303
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 ."

M. Yoshida, K. Yanagisawa, Y. Shimizu, S. Nagayama (OAO, NAOJ)
and N. Kawai (Tokyo Tech) report on behalf of the MITSuME
collaboration:

We performed optical imaging observation (g', Rc, and Ic) of the
field of GRB 080212 (Ziaeepour et al. GCN 7296
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 ) with 50cm MITSuME
telescope at Okayama Astrophysical Observatory from UT 17:36:37
(124 sec after the trigger) to UT 20:30:38 on Feb 12 2008.

We found a 18 mag star in the vicinity of the XRT position (Goad
et al. GCN 7300
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 ). This is the late-K star reported by Berger (GCN
7304
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 ). Although we could not spatially resolve the faint source
close to this star reported by Berger (GCN7304
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 ), we found that
a fading component is overlaid on the star. This component is
a GRB afterglow candidate. We estimated the magnitudes of the
fading component by subtracting the flux of the star at 2 hours
after the trigger from the star magnitude at early time.

The estimated magnitudes of the fading component are summarized
below.

Observation date  2008-02-12 UT

mid-UT    exp-T         g'           Rc           Ic
---------------------------------------------------------
17:42:47   10min   19.46+-0.26  17.77+-0.15  17.98+-0.22
18:00:27   22min   > 21.0       18.77+-0.14  18.91+-0.21
18:19:08   52min   > 21.0       19.88+-0.10  > 20.5
18:58:37  113min   > 21.0       > 20.5       > 20.5
---------------------------------------------------------

K. McLean (GSFC/UMD), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC),
E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. Ukwatta (GWU), H. Ziaeepour (UCL-MSSL)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 080212 (trigger #303105)
(Ziaeepour, et al., GCN Circ. 7296
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 ).  The BAT ground-calculated position is
RA, Dec = 231.145, -22.739 deg, which is 
   RA(J2000)  =  15h 24m 34.8s 
   Dec(J2000) = -22d 44' 19" 
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 35%.
 
The mask-weighted light curve shows the main burst acivity starting
at about T-60 sec, the main peak at ~T+5 sec, and ending at about T+110 sec.
There is a weak peak at T+250 to T+350 sec, which matches a flare
in in the XRT lighcurve peaking at about T+250 sec.
T90 (15-350 keV) is 123 +- 13 sec (estimated error including systematics).
 
The time-averaged spectrum from T-60.5 to T+75.7 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.31 +- 0.64, 
and Epeak of 67.6 +- 13.1 keV (chi squared 52.75 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 2.9 +- 0.3 x 10^-06 erg/cm2
and the 1-sec peak flux measured from T+3.75 sec in the 15-150 keV band is
1.2 +- 0.3 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.59 +- 0.12 (chi squared 68.06 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/303105/BA/

M. De Pasquale and H. Ziaeepour (MSSL/UCL)
report on behalf of the Swift team:

The Swift/UVOT observed the field of GRB 080212 (trigger 303105)
starting 110 seconds  after the BAT trigger (Ziaeepour et al
GCN Circ. 7296
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 ), which occurred at 17:34:33 UT.
A source is detected in the enhanced XRT error circle reported
by Evans et al (GCN circ. 7300
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 ), blended with the K-type star
mentioned in GCN 7304
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  by Berger et al.
The detection is only in the early V band exposures. There was
no other 3-sigma detection of the afterglow in any exposure
in any of the UVOT filters.

  We do caution that photometry for this burst has been
carried out in very difficult conditions. Furthermore, no
correction has been made for the non-negligible Galactic
extinction towards the burtst, which amounts to E(B-V) = 0.16

The detections and 3-sigma upper limits in the UVOT photometric
system (Poole et al MNRAS 383, 627 (2008)) are summarized in
the following table:


   Filter  Tstart(s)  Tstop(s)  Exp(s)     Mag / Upper limit

   V          110       510      393        17.8 +/- 0.1

   V         4734      6166      393        19.3 +/- 0.3

   V        21968     22876      893            >20.3


   B         4323      4522      393            >20.7

   B        11320     40999     1774            >21.2


   U         4119      5548      393            >20.3

   U        10408     40703     3400            >21.5


   UW1       3919      5344      393            >20.0

   UW1       9502     50920     4309            >21.2


   UM2       3741      6300      323            >19.3

   UM2      15290     45066     3413            >20.6


   UW2      4529       5961      393            >19.4

   UW2     21062      21961      893            >20.7

Poonam Chandra (NRAO/UVA) 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 080212 (GCN 7296
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 ) at a frequency of 8.46 GHz on 2008 February
13.53 UT. The radio afterglow of the GRB is undetected at the
Swift-XRT position (GCN 7300
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 ) or optical afterglow position (GCN 7303
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 ).
The peak flux density at the afterglow position is 83 +/- 51 uJy.


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

P. D'Avanzo, L.A. Antonelli, S. Covino, D. Fugazza, L.  Calzoletti, S. 
Campana, G.  Chincarini, M.L. Conciatore, S. Cutini, V. D'Elia, F. 
D'Alessio, F. Fiore, P. Goldoni, D. Guetta,  C. Guidorzi, G.L. Israel, 
E. Maiorano, D. Malesani, N. Masetti, A. Melandri, E.J.A. Meurs, L. 
Nicastro, E. Palazzi, E. Pian, S. Piranomonte, L.  Stella, G.  Stratta, 
G. Tagliaferri, G. Tosti, V. Testa, S.D. Vergani,  F. Vitali report on 
behalf of the REM team:

We performed a more careful analysis of the REM H-band images of GRB 
080212 (Ziaeepour et al. GCN 7296
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 ). We confirm the afterglow detection 
reported in D'Avanzo et al. (GCN  7302
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 ).The observations have been 
carried out on Feb 13.2063 UT (about 11.4 hours after the burst) and 
consist of three sets of images (lasting 10, 30 and 60 s respectively).

We confirm the presence of a H = 15.3 � 0.2 object (calibrated against 
the 2MASS catalogue) about 2.5" East of the K-type star (Berger, GCNs 
7294
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  & 7304). The object is visible in both the 30 s and 60 s images at 
the following coordinates (J2000):

R.A. = 15:24:35.42
Dec. = -22:44:28.8

with an uncertainty of 0.3" (the REM pixel size is 1.2"/pixel) .

When compared to the GROND optical detection (obtained about 1.7 hours 
later, Kuepcue Yoldas et al. GCN  7303
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 ), our H-band measurement implies 
a colour I-H ~ 7 mag, which is very red. A possible way out is to invoke 
remarkable flaring activity around the time of the REM observation. We 
note that the X-ray light curve (available at: 
http://www.swift.ac.uk/xrt_curves/00303105/) shows some evidence for 
rebrightening about 2 hr before the REM observation.

A finding chart, showing the detection at different H-band images can be 
found at the following URL:

 http://www.brera.inaf.it/utenti/davanzo/public/grb/GRB080212/GRB080212_REMIR_FC.jpg

P. D'Avanzo, D. Fugazza (INAF-OAB), L.A. Antonelli (INAF-OAR), S. 
Covino, G. Chincarini, C. Guidorzi, G. Tagliaferri (INAF-OAB), V. 
D'Elia, F. Fiore, S. Piranomonte, L. Stella (INAF-OAR), M. Della Valle 
(INAF-OAA), S. D. Vergani (DIAS-DCU) report on behalf of the MISTICI 
collaboration:

We observed the optical afterglow of GRB 080212 (Ziaeepour et al., GCN 
7296
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 ) with the ESO-VLT equipped with the FORS2 camera in imaging mode at 
three different epochs. Observations have been carried out in R-band on 
Feb 13.3101 UT, Feb 13.3682 UT and Feb 14.2838 UT (0.58, 0.64 and 1.55 
days after the burst, respectively).

We found that between the first two epochs the afterglow faded very 
rapidly, with a decay index of alpha ~ 5.5. Very likely, the afterglow 
underwent a remarkable increase of its optical/NIR flux, probably 
related to the brightening observed in the X-rays about 4 hours before 
our VLT observations (see D'Avanzo et al., GCN 7310
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 ).

Assuming the above decay index, we estimate R ~ 20.8 at the epoch of the 
REM detection (D'Avanzo et al., GCN 7302
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 ) with an implied colour R-H~5

The decay of the afterglow then slowed down between the last two epochs 
and we measure R~25 in our last observation.

Lokesh, V. Venkat, J. Jain, S. Vadawale and B.G. Anandarao
Physical Research Laboratory, Ahmedabad, India.

We made infrared photometry in J band at Mt. Abu 1.2 m Cassegrain telescope
using NICMOS camera on the GRB 080212 (Ziaeepour et al. GCN 7296
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 )
during 2008 Feb 13 under good sky conditions. The H band magnitude was
earlier reported by P. D'Avanzo et. al (GCN 7310
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 ).
The calibration was made on the bright star SAO 183333.
The overall integration time and the magnitude along with the associated
error are given below:
UT           Integration time	J band magnitude+/-error
13.97		1080s		16.8+/-0.1