GRB 080207

J. L. Racusin (PSU), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), P. J. Brown (PSU),
D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC),
P. A. Evans (U Leicester), S. D. Hunsberger (PSU),
J. A. Kennea (PSU), C. B. Markwardt (CRESST/GSFC/UMD),
F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester),
D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC),
R. L. C. Starling (U Leicester), M. C. Stroh (PSU) and
T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:

At 21:30:21 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 080207 (trigger=302728).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 207.513, +7.514 which is 
   RA(J2000)  = 13h 50m 03s
   Dec(J2000) = +07d 30' 50"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  This was an image-trigger, so the TDRSS
lightcurve show little activity. 

The XRT began observing the field at 21:32:25 UT, 124 seconds after the
BAT trigger. XRT found a bright, uncatalogued X-ray source
located at RA, Dec 207.5117, +7.5018 which is
   RA(J2000)  =  13h 50m 02.8s
   Dec(J2000) =  07d 30' 06.4"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). 
This location is 44 arcseconds from the BAT on-board position,
within the BAT error circle. The initial flux in the 2.5s image
was 8.2e-09 erg/cm2/s (0.2-10 keV). 

 UVOT took a finding chart exposure of 55 seconds with the White
(160-650 nm) filter starting 140 seconds after the BAT trigger. No
afterglow candidate has been found in the initial data products. The
3 sigma upper limit at the XRT position is white > 20. 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 (racusin 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.)

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

Using 199 s of overlapping XRT Photon Counting mode and UVOT
V-band data for GRB 080207, 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 = 207.51253, +7.50245 which is equivalent
to:

RA (J2000): 13h 50m 3.01s
Dec (J2000): +07d 30' 08.8"

with an uncertainty of 2.9 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.

J. L. Racusin (PSU) reports on behalf of the Swift-XRT Team:

We have analysed the first 4 orbits of Swift-XRT data obtained for GRB
080207 (Racusin et al. GCN Circ. 7264
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 ), totaling 64 s of Windowed Timing
(WT) data and 5.7 ks of Photon Counting (PC) data.  The enhanced XRT
position is given in Beardmore et al. (GCN 7265
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 ).

The X-ray light-curve can be fit by a broken power-law with an initial
bright short flat phase with a a break at 205 +/- 73 sec followed by a
power-law with a decay slope of 1.5 +/- 0.1.

The WT data (133-197 seconds) can be modeled as an absorbed power-law with
photon index of 1.1 +/- 0.1 and a total absorbing column of NH = (85 +/-
10)e20 cm^-2.  The PC data (4.7-17.1 ks) can be modeled as an absorbed
power-law with photon index of 2.4 +/- 0.2 and a total absorbing column of
NH = (75 +/- 17)e20 cm^-2.  Both fits are in excess of the Galactic value
of 1.95e20 cm^-2. The 0.3-10 keV observed (unabsorbed) flux during this
time is 5.80e-9 (5.81e-9) erg cm^-2 s^-1 and 1.15e-11 (1.16e-11) erg cm^-2
s^-1 for WT and PC, respectively.

Assuming the source continues to decay with the same decay index of 1.5,
we predict an XRT count rate of 7.6e-3 counts/s at T+24 hours, which
corresponds to an 0.3-10.0 keV observed flux of 6.6e-13 ergs cm^-2 s^-1.

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

Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report:

We imaged the field of GRB 080207 detected by SWIFT
(trigger 302728) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

Although the notice was received 100s after the trigger,
the observations started 1075s later
because the field was not risen at Calern during the burst.
First images are two low in elevation.
Stars become detectable on images ~1500s after the trigger.
Weather conditions were excellents.

The date of trigger : t0 = 2008-02-07T21:30:21
No afterglow was found at position delivered by
Beardmore et al. (GCNC 7265):

t0+1563s to t0+1653s : R > 14.3 (elevation 2.5�)
t0+1670s to t0+1760s : R > 14.9 (elevation 2.8�)
t0+3388s to t0+3568s : R > 16.2 (elevation 8�)
t0+3388s to t0+7526s : R > 19.0 (elevation 20�)

Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.

This message may be cited.

A. Cucchiara (PSU), J. Racusin (PSU)
report on behalf of the Swift-UVOT team:

The Swift/UVOT observed the field of GRB080207 (trigger #302728)
starting 55 sec days after the BAT detection (Racusin et
al. 2008, GCN Circ. 7264
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 ). We do not find any new source in any
of the UVOT coadded observations inside the XRT enhanced error
circle (Beardmore et al. 2008, GCN Circ. 7265
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 ).

The 3-sigma upper limits (in the UVOT photometric system,
Breeveld et al., GCN Circ. 6614
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 ) are listed.

Filter     Tstart   Tstop     Exp    Upper limit  
             (s)      (s)     (s)           
white        55      11428   1167      22.40
v          4733      13063   1097      20.50
b          5553      16909    983      21.53
u          5347       6982    393      20.57
uvw1       5143       6777    393      20.75
uvm2       4937       6572    393      20.58
uvw2       5963      12334   1082      21.62

The values quoted above are not corrected for the expected Galactic
extinction corresponding to a reddening of E_{B-V} = 0.02  mag in the
direction of the burst (Schlegel et al. 1998).

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 080207 (Racusin et al., GCN 7264
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 ). A 
preliminary analysis of the first set of JHK exposures does not reveal 
any optical afterglow candidate inside the XRT error box (Beardmore et 
al., GCN 7265
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 )  We derive the following 3sigma upper limits (calibrated 
against the 2MASS catalog):

J > 16.7 (7.8 hours after the burst)
H > 15.9 (7.7 hours after the burst)
K > 13.9 (10.1 hours after the burst)

I. Khamitov (TUG), O. Kose, K.Yakut (Ege Uni.),
Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.)
I. Bikmaev, N. Sakhibullin (KSU/AST)
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),

report:

We have observed field of the GRB080207 (trigger=302728, GCN Circ. 7264
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 ) 
with Russian-Turkish 1.5-m telescope  (RTT150, Bakirlitepe, TUBITAK 
National Observatory, Turkey) 07 Feb between 22:04UT and 22:27UT, i.e. 
starting about 34 min after the burst, using ANDOR CCD.

Series of 20*30sec direct images in Rc band were taken. We found no 
afterglow candidate inside of XRT error circle. Using USNO-B1 stars we 
estimated limiting magnitude of the co-added frame as R~21.8 mag.

The finding chart can be found at:
http://hea.iki.rssi.ru/grb/080207/indexeng.html


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M. Stamatikos (GSFC/ORAU), 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), J. L. Racusin (PSU),
T. Sakamoto (GSFC/UMBC), G. Sato (GSFC/ISAS), J. Tueller (GSFC),
T. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 080207 (trigger #302728)
(Racusin, et al., GCN Circ. 7264
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 ).  The BAT ground-calculated position is
RA, Dec = 207.514, 7.492 deg which is 
   RA(J2000)  = 13h 50m 3.3s 
   Dec(J2000) =  7d 29' 32" 
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
 
The mask-weighted light curve shows a long smooth rise starting at ~T-20 sec,
peaking around T+100 sec, then dropping to a minimum around T+200 sec,
then rising again out to T+320 sec at which point the location went out
of the BAT FOV when the spacecraft slewed to a new target.
T90 (15-350 keV) is >300 sec (estimated error including systematics).
 
The time-averaged spectrum from T+4.7 to T+332.9 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.17 +- 0.27, 
and Epeak of 107.8 +- 72.5 keV (chi squared 51.31 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 6.1 +- 0.2 x 10^-06 erg/cm2
and the 1-sec peak flux measured from T+330.34 sec in the 15-150 keV band is
1.0 +- 0.3 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.58 +- 0.06 (chi squared 57.73 for 57 d.o.f.).  All the quoted errors
are at the 90% confidence level. 

The BAT characteristics of this burst, particularly the long smooth 
lightcurve, suggest that it might be at high redshift, but the high 
absorption of the XRT spectrum (Racusin et al. GCN 7266
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 ) make it unlikely.
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/302728/BA/

A. C. Updike (Clemson University), P. A. Milne (U Arizona), G. G.
Williams (MMTO), and D. H. Hartmann (CU) report on behalf of the
Super-LOTIS team:

The 0.6m Super-LOTIS telescope began observations of the field of GRB
080207 (Racusin et al., GCN 7264
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 ) approximately 13 hours and 16 min
after the trigger. Observations consisted of 58x60 second exposures in
the R band, under decent weather conditions.

No afterglow was detected within the XRT refined error circle (Beardmore
et al., GCN 7265
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 ) down to a limiting magnitude of 20.8 (as derived from
USNO B1.0 R2 magnitudes upon comparison to field stars).

This message may be cited.

A. Cucchiara and D. B. Fox (PSU) reports on behalf of a larger
collaboration:

"We have imaged the field of GRB 080207 (Racusin et al., GCN 7264
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 )
with the Gemini South + GMOS in griz bandds starting at 0.41 days
after the trigger.

We took a sequence of 5x 180s images in each band (total exposure
900s).  Our co-added images do not reveal any source inside the XRT
refined error circle (Beardmore et al., GCN 7265
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 ).  Using three
objects from the SDSS catalog to establish photometric zero-points, we
calculate the following 2-sigma upper limits on the emission of any
optical afterglow + host galaxy: g > 24.1 mag, r > 24.5 mag, i > 24.2
mag, z > 25.0 mag."

M. Stamatikos (GSFC/ORAU), 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),
J. L. Racusin (PSU), T. Sakamoto (GSFC/UMBC), G. Sato (GSFC/ISAS),
J. Tueller (GSFC), T. Ukwatta (GWU)
(i.e. the Swift-BAT team):

Using the data set from T-239 to T+963 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 080207 (trigger #302728)
(Racusin, et al., GCN Circ. 7264
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 ).  The BAT ground-calculated position
is RA, Dec = 207.514, 7.492 deg which is
   RA(J2000)  = 13h 50m 3.3s
   Dec(J2000) =  7d 29' 32"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows a long smooth rise starting at
~T-20 sec, peaking around T+100 sec, then dropping to a minimum around
T+200 sec, then rising again out to ~T+340 sec at which point the 
location went out of the BAT FOV when the spacecraft slewed to a new
target.  Based on the raw counting rates, which are somewhat sensitive
to photons through the side of the instrument, there was not significant
emission above about 50 keV after this time.  T90 (15-350 keV) is 
340 +- 20 sec (estimated error including systematics).

The time-averaged spectrum from T+4.7 to T+332.9 sec is best fit by a
power law with an exponential cutoff.  This fit gives a photon index
1.17 +- 0.27, and Epeak of 107.8 +- 72.5 keV (chi squared 51.31 for
56 d.o.f.).  For this model the total fluence in the 15-150 keV band is
6.1 +- 0.2 x 10^-06 erg/cm2 and the 1-sec peak flux measured from
T+330.34 sec in the 15-150 keV band is 1.0 +- 0.3 ph/cm2/sec.  A fit to
a simple power law gives a photon index of 1.58 +- 0.06 (chi squared
57.73 for 57 d.o.f.).  All the quoted errors are at the 90% confidence
level.

The BAT characteristics of this burst, particularly the long smooth
lightcurve, suggest that it might be at high redshift, but the high
absorption of the XRT spectrum (Racusin et al. GCN 7266
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 ) make it
unlikely.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/302728/BA/

A. Kuepcue Yoldas, A. Yoldas, J. Greiner, T. Kruehler (all MPE Garching),
S. Klose (Tautenburg Obs), G. Szokoly (Budapest Univ.) report for the
GROND team:

We observed the field of GRB 080207 detected by Swift/BAT (Racusin et al.
2008, GCN 7264
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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. 08, at 06:35 UT, about 9 hrs after the GRB,
under poor conditions (particularly high humidity and airmass of 1.7-1.34).

No source is detected within the 3-sigma XRT error circle (Beardmore et al.
2008, GCN 7265
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 ). Comparison of the co-added images (with 3440 sec effective
exposure time in griz and 2400 seconds in JHK) to the Digital Sky Survey 
and 2MASS yields the following 3-sigma upper limits:
g' > 23.9,  r' > 23.8,  i' > 23.5,  z' > 22.8,  J > 21.0,  H > 19.7,  K > 19.0.

V. Muñoz Marín, J. Sabater, A.J. Castro-Tirado, J. Gorosabel, M.
Jelínek (IAA-CSIC), A. de Ugarte Postigo (ESO, Santiago), report:

"We carried out BVRI-band observations of the GRB 080207 XRT enhanced
position of (Beardmore et al., GCN 7265
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 ) with the 2.5m NOT(+MOSCA) at
Roque de los Muchachos observatory. A preliminary analysis reveals no
optical source in the XRT error circle brighter than R~23.5 at Feb
8.26389-8.27778 UT (8.83 - 9.16 hours after the GRB)."

D. Fugazza (INAF-OAB), V. D'Elia (INAF-OAR), P. D'Avanzo, S. Covino and 
G. Tagliaferri (INAF-OAB) report, on behalf of the MISTICI collaboration:

We observed the field of GRB 080207 (Racusin et al., GCN 7264
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 ) with the 
Very Large Telescope equipped with the SINFONI near infrared camera in 
imaging mode. Observations have been carried out on Feb 08.3673, i.e. 
about 11.3 hours after the burst and about 2 hours after the REM 
(D'Avanzo et al., GCN 7269
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 ) and GROND (Kuepcue Yoldas et al. GCN 7279
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 ) 
NIR observations. We do not detect any afterglow candidate inside the 
XRT error box (Beardmore et al., GCN 7265
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 ).  We derive the following 
3sigma upper limits (calibrated against standard stars taken the same 
night):

J > 23.5
H > 22.8
K > 21.5

We acknowledge support from the ESO staff.

M. Andreev (Terskol Branch of Institute of Astronomy) V. Petkov, A. Kurenya 
(BNO INR RAS), A. Pozanenko (IKI) on behalf of larger GRB follow up 
collaboration  report:

We observed the GRB080207 (Racusin et al. GCN 7264
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 ) with Zeiss-600 of 
Mt.Terskol observatory on Feb.07-08. Two series in R-filter were completed. 
We do not detect new sources within XRT error circle (Beardmore et al. GCN 
7265
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 ). The limiting magnitudes against USNO-B1.0 are following:

UT,              Exposure,   R_mag
(mid time)

Feb.7.958    20 x 60s    >20.3
Feb.8.102    40 x 90s    >21.0

The message may be cited.