GRB 110210A

V. D'Elia (ASDC), W. H. Baumgartner (GSFC/UMBC),
A. P. Beardmore (U Leicester), S. Campana (INAF-OAB),
J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester),
J. M. Gelbord (PSU), B. Gendre (ASDC), C. Guidorzi (U Ferrara),
S. T. Holland (CRESST/USRA/GSFC), C. B. Markwardt (NASA/GSFC),
P. T. O'Brien (U Leicester), J. P. Osborne (U Leicester),
C. Pagani (U Leicester), K. L. Page (U Leicester), M. Perri (ASDC),
M. H. Siegel (PSU), R. L. C. Starling (U Leicester) and
G. Stratta (ASDC) report on behalf of the Swift Team:

At 09:52:41 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 110210A (trigger=445141).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 13.077, +7.792 which is 
   RA(J2000) = 00h 52m 19s
   Dec(J2000) = +07d 47' 30"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve did not show a significant
peak, which is typical for an image trigger. 

The XRT began observing the field at 09:54:57.8 UT, 136.5 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 13.05706, 7.78019 which is
equivalent to:
   RA(J2000)  = 00h 52m 13.69s
   Dec(J2000) = +07d 46' 48.7"
with an uncertainty of 4.1 arcseconds (radius, 90% containment). This
location is 83 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.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 5.28
x 10^20 cm^-2 (Kalberla et al. 2005). 

The initial flux in the 2.5 s image was 2.16e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 144 seconds after the BAT 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 typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.06. 

Burst Advocate for this burst is V. D'Elia (delia AT asdc.asi.it). 
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.)

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

Using 1592 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 110210A, 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 = 13.05659, +7.77968 which is equivalent
to:

RA (J2000): 00h 52m 13.58s
Dec (J2000): +07d 46' 46.9"

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) and Evans
et al. (2009, MNRAS, 397, 1177).

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

M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), V. D'Elia (ASDC), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(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 110210A (trigger #445141)
(D'Elia, et al., GCN Circ. 11687
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 ).  The BAT ground-calculated position is
RA, Dec = 13.108, 7.778 deg, which is 
   RA(J2000)  =  00h 52m 25.9s 
   Dec(J2000) = +07d 46' 39.5" 
with an uncertainty of 3.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 83%.
 
The mask-weighted light curve shows the emission starting at ~T-100 sec,
peaking at ~T+50 sec, and ending at ~T+150 sec.  T90 (15-350 keV) is
233 +- 60 sec (estimated error including systematics).
 
The time-averaged spectrum from T-102.9 to T+153.6 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.73 +- 0.29.  The fluence in the 15-150 keV band is 9.6 +- 1.9 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-54.44 sec in the 15-150 keV band
is 0.3 +- 0.1 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/445141/BA/

G. Stratta, V. D'Elia (ASDC) report on behalf of the Swift-XRT team:

We have analysed 5.6 ks of XRT data for GRB 110210A (D'Elia  et al. GCN
Circ. 11687
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 ), from 126 s to 19.3 ks after the  BAT trigger. The data
comprise 226 s in Windowed Timing (WT) mode (the first 9 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Goad et al.
(GCN. Circ 11689).  After an initial fading behavior, the light curve
is consistent with a constant source of mean count rate 4.5e-01 ct/sec.
A power-law fit gives an index of 0.0 (+/-0.3).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index	of 3.10 (+0.09, -0.08). The
best-fitting absorption column is  2.16 (+0.17, -0.16) x 10^21 cm^-2,
in excess of the Galactic value of 5.3 x 10^20 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 2.16 (+0.15, -0.19)
and a best-fitting absorption column of 7.5 (+4.5, -1.9) x 10^20 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.6 x 10^-11 (4.6 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     7.5 (+4.5, -1.9) x 10^20 cm^-2
Galactic foreground: 5.3 x 10^20 cm^-2
Excess significance: 6.4 sigma
Photon index:	     2.16 (+0.15, -0.19)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00445141.

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

[GCN OPS NOTE(10feb11): Per author's request, the fourth sentence
was replaced. Acknowledgement to H.Kann.]

G. Greco (INAF-Astronomical Observatory of BOLOGNA), C. Bartolini, A. Guarnieri,
A. Piccioni (University of Bologna), G. Pizzichini (INAF/IASF-Bologna),
G. Gavazzi (University of Milano-Bicocca) and R. Gualandi
(INAF-Astronomical Observatory of BOLOGNA) report:

We observed the location of the GRB 110210A (D'Elia, et al., GCN Circ. 11687
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 )
with the 152 cm Cassini Telescope located in Loiano, Italy, equipped with BFOSC.

Two R-band observations (2x900 sec) were obtained during twilight at high airmass.
The mean time was February 10.756 UT (0.345 day after the burst).

No source was detected inside the XRT error circle
(Goad, et al., GCN. Circ. 11689) in the coadded frame.
The limiting magnitude is R = 18  based on the USNO-A2 catalog
and not corrected for the Galactic extinction.

This message can be cited.

Bret L. Little, Ben Boizelle, Kimberly Bates, Michael Abbott, and J.
Ward Moody report for
Brigham Young University�s ROVOR team:

We report our observations in the field of GRB 110210A (Swift trigger
445141, D'Elia et al., GCN 11687
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 ) on Feb 11 beginning 16.25 hours post-burst
at 02:09:18 UT. The 0.41m ROVOR telescope in Delta, Utah,
automatically imaged this location upon power up.

We combined sixteen 120 second exposures, four each in BVRI. No
detection of an afterglow
inside the XRT error circle (Goad, et al., GCN. Circ. 11689) was obtained
after stacking the images. An upper limit of 20.0 � 0.5 mag in R2
was found by comparing against USNOB values.

A. Volnova (SAI MSU), Korobtsev (ISTP),  E. Klunko (ISTP),  A.
Pozanenko (IKI) on behalf of larger GRB follow up collaboration
report:

We observed the field of the Swift GRB 110210A (D'Elia et al., GCN
11687
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 ) with AZT-33IK telescope of Sayan observatory (Mondy) on Feb. 10
between (UT) 11:10 - 12:28 under poor weather conditions and mean
seeing of about ~2.3". We took several series with exposure of 60
seconds in R-band. In a stacked image we do not detect any source in
enhanced XRT error circle (Goad et al. GCN 11689
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 ). The upper limit (3
sigma) of the stacked image based on SDSS field star
J005218.01+0746740.1 (assuming R = 18.73) is the following:

T0+      Filter,   Exposure,      OT mag.,  UpperLimit
(mid, d)              (s)

0.08122  R      69x60               n/d           19.4

M. De Pasquale (MSSL-UCL) and V. D'Elia (ASDC) on behalf of the
Swift/UVOT team report:

The Swift/UVOT began settled observations of the field of GRB
110210A 144 s after the BAT trigger (D'Elia et al., GCN Circ.
11687
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 ). No optical afterglow consistent with the enhanced XRT position 
(Goad et al., GCN Circ. 11689
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 ) is detected in the initial UVOT finding 
charts nor in the summed exposures in all filters. (Poole  et al. 2008, 
MNRAS, 383, 627) for the finding chart (FC) exposures and subsequent 
exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           144          294          147         >20.1
u_FC               302          552          246         >19.4
white              144         7686          746         >21.0
v                  633        13497         1238         >19.7
b                  558         7481          526         >20.1
u                  302         7276          756         >19.9
w1                 682         7072          294         >19.5
m2                 660        18180          839         >20.6
w2                 608        12588         1291         >21.0

The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.06 in the direction of the burst
(Schlegel et al. 1998).

[GCN OPS NOTE(16feb11): Per author's request, the author list was added.]