GRB 080701, GRB 080701A

J. Wren, W.T. Vestrand, P.R. Wozniak, H. Davis, B. Norman
of Los Alamos National Laboratory report:

The RAPTOR telescope system responded to Swift trigger
315615 (Stroh et al., GCN 7910
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 ) under good observing conditions.
Our narrow-field instruments began observing the location at
10:14:06.47 UTC, 28.8 s after the Swift trigger.  We detect no
counterpart at the improved XRT position (Evans et al., GCN 7914
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 ).
The limiting magnitudes of our unfiltered observations when
calibrated to the USNO-B1 R-band are given in the following table.
The GRB location was also within the field of view of our
continuous all-sky monitoring system.  We can place 3 sigma limits
at or below magnitude 9.4 during the time period within 2
minutes both before and after the trigger.  

t-mid(s)    exp(s)     mag     mag-err
--------------------------------------------
-11.68      10.0       9.7     3 sigma limit
11.57       10.0      10.0     3 sigma limit
34.80       10.0       9.9     3 sigma limit
71.45       45.0      19.3     3 sigma limit
173.93     100.0      19.8     3 sigma limit
300.65     100.0      19.9     3 sigma limit
561.10     270.0      20.5     3 sigma limit

M.C. Stroh (PSU) reports on behalf of the Swift-XRT team.

We have analyzed the first four orbits of Swift-XRT data obtained for  
GRB 080701 (Stroh et al., GCN Circ. 7910
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 ), totaling 2.4ks of Photon  
Counting data.

The UVOT-enhanced XRT position has been given by Evans et al. in GCN  
Circ 7914
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 .

The X-ray light-curve can be fit by a power-law with a decay index of  
1.04 +/- 0.27. Assuming a constant decay rate, we predict counting  
rates at T+24 and T+48 hours of 4.55e-3 and 2.21e-3 cts/s respectively.

The spectrum can be fit with a power-law in excess of the Galactic  
value (1.78e21 cm-2, Kalberla et al. 2005), with an excess column of  
9.21 (+6.43/-4.78)e21 cm^-2 and a photon index of 2.93 (+0.79/-0.59).  
The observed (unabsorbed) 0.3-10 keV flux is 3.55e-12 (1.976e-11) ergs/ 
cm^2/s.

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

C. Peters (Goshen College) and P. Garnavich (Notre Dame) report:

We observed the field of GRB 080701A with the Vatican Advanced Technology
Telescope (VATT) beginning July 1.46 (UT) or 45 minutes after
the bursts (Stroh et al. GCN 7910
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 ). Four exposures totaling 190 sec
in the R-band were obtained. The combined image was calibrated assuming
the
brightness of the USNO-B1 star at RA=3:03:21.50 DEC=75:28:15.48
is R=16.52.

No source is detected down to R=22.0 at the improved XRT
position (Evans et al. GCN 7914
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 ).

Rossi, A. (TLS Tautenburg), Gonsalves, E. (U. Dartmouth), Schulze, S. (TLS  
Tautenburg), Klose, S. (TLS  Tautenburg), Filgas, R. (TLS  Tautenburg), 
and Ludwig, F. (TLS  Tautenburg) 
report on behalf of a larger collaboration:

We observed the X-ray error circle of the Swift GRB 080701A (Evans, P. A. 
et al., GCN 7914
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 ; Stroh, M. C. et al., GCN 7910
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 ) with the TLS 1.34m Schmidt 
telescope under good  observing conditions (seeing is about 1-2 arcsec and 
very good visibility). We obtained in total 10 x 150 sec images starting at 
21:02 UT and 5 x 300 sec images starting at 21:40 UT in the I band. We did 
not find any new source in the stacked image down to the 3-sigma limiting 
magnitude of 21.7 mag calibrated on USNO-B1 field.

This message can be cited.

F.E. Marshall (NASA/GSFC) and M.C. Stroh (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT observed the field of GRB 080701A starting 2983 s after
the BAT trigger (Stroh et al., GCN Circ. 7910
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 ).  We do not find a source
in any of the UVOT observations inside the enhanced XRT error circle
(Evans et al., GCN Circ. 7914
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 ). The 3-sigma upper limits for detecting
a source in the first finding chart (FC) exposure and co-added frames are:

Filter            T_start(s)   T_stop(s)     Exp(s)     Mag (3-sigma UL)

white (FC)        2983         3082           98        >19.7
white             2983         9403          736        >21.0
v                 3914         4113          197        >19.1
b                 3298         4934          393        >20.2
u                 3093         4728          393        >19.9
uvw1              4324         4523          197        >20.0
uvm2              4119         4318          197        >19.6
uvw2              3709         3908          197        >20.2

The values quoted above are not corrected for the expected Galactic
extinction corresponding to a reddening of E(B-V) = 0.54 mag in
the direction of the burst (Schlegel et al. 1998).

P.A. Milne (U Arizona) reports on behalf of the Super-LOTIS team:

The robotic 0.6m Super-LOTIS telescope began R-band observations of the error
region of GRB 080701A at 10:14:25 UT, 49 seconds after the trigger.
Initial 10 and 20 second exposures reveal no sources other than those
present in the relevant DSS image. A stack of 30x60sec images
reveals no source at the location of the XRT source (Stroh et al.,
GCN 7911
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 ), down to a 3-sigma limiting magnitude of R~19.5. Comparisons of
initial and final images reveals no brightening or fading sources.

We used the USNO-B star at RA=03:02:55.5, Dec=+75:28:42 to derive the
R2 magnitude upper-limit.

This message can be cited.

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

Using 699 s of overlapping XRT Photon Counting mode and UVOT
data for GRB 080701, 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 = 45.83882, +75.47479 which is equivalent
to:

RA (J2000): 03h 03m 21.32s
Dec (J2000): +75d 28' 29.3"

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
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.

E. Fenimore (LANL), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC),
J. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
M. C. Stroh (PSU), J. Tueller (GSFC), T. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-120 to T+285 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 080701A (trigger #315615)
(Stroh, et al., GCN Circ. 7910
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 ).  The BAT ground-calculated position is
RA, Dec = 45.944, 75.481 deg which is 
   RA(J2000)  =  03h 03m 46.5s 
   Dec(J2000) = +75d 28' 50.7" 
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 55%.
 
The mask-weighted light curve shows a single FRED-like peak starting
at ~T-2 sec, peaking at ~T+0 sec, and ending at ~T+20 sec.
T90 (15-350 keV) is 18 +- 9 sec (estimated error including systematics).
 
The time-averaged spectrum from T-2.7 to T+24.6 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.24 +- 0.17.  The fluence in the 15-150 keV band is 7.1 +- 0.7 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.08 sec in the 15-150 keV band
is 2.2 +- 0.2 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/315615/BA/

M.C. Stroh, C. Pagani (PSU) and P. Evans (U. Leicester) report on  
behalf of the Swift-XRT team.

The XRT began observing the field at 11:00:14.4 UT, 2796.8 seconds
after the BAT trigger. Using promptly downlinked data we find an
uncatalogued X-ray source located at RA, Dec 45.83937, 75.47535 which
is equivalent to:
  RA(J2000)  = 03h 03m 21.45s
  Dec(J2000) = +75d 28' 31.3"
with an uncertainty of 3.1 arcseconds (radius, 90% containment). This
location is 59 arcseconds from the BAT onboard position, within the BAT
error circle.

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.78e+21
cm-2, Kalberla et al. 2005), with an excess column of 6.3
(+3.88/-3.07) x 10^21 cm-2 (90% confidence).

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

M. C. Stroh (PSU), A. P. Beardmore (U Leicester), D. N. Burrows (PSU),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC),
C. Guidorzi (INAF-OAB), E. A. Hoversten (PSU), C. Pagani (PSU),
K. L. Page (U Leicester), D. M. Palmer (LANL),
D. Perez (U Leicester), P. Romano (INAF-IASFPA),
T. Sakamoto (NASA/UMBC), R. L. C. Starling (U Leicester),
T. N. Ukwatta (GSFC/GWU), L. Vetere (PSU) and H. Ziaeepour (UCL-MSSL)
report on behalf of the Swift Team:

At 10:13:37 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 080701 (trigger=315615).  Swift did not immediately slew
due to an Earth limb constraint.  The BAT on-board calculated location is 
RA, Dec 45.837, +75.492 which is 
   RA(J2000) = 03h 03m 21s
   Dec(J2000) = +75d 29' 30"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a smooth peak
structure with a duration of ~15 sec.  The peak count rate
was ~2500 counts/sec (15-350 keV), at ~1 sec after the trigger. 

Swift was unable to slew to the source due to due to Earth limb
constraints. X-ray telescope and UV/optical telescope observations of
this region will become possible at T+50 minutes. 

Burst Advocate for this burst is M. C. Stroh (stroh AT astroh.org). 
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.)