GRB 041211

A. Monfardini, C. Guidorzi, C.J. Mottram, C. Mundell (Liverpool John 
Moores University) and the Liverpool GRB team, on behalf of the larger 
Robonet consortium, report:

"We obtained late BVRI images of the SXC error box of GRB041211 (GCN 2839
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 ) 
with the 2-m Faulkes Telescope North on Maui. New observations began on 
December 15.549 UT (4.069 days after the GRB) under average seeing conditions.

We compared 3x120 sec. R filter exposures with an early 120 sec exposure 
(GCN 2845
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 ). We found no significant variations or disappearances. 
We thus conclude:

Time from GRB   Time from GRB   ExpTime    Filter    Limit Mag.
(days)          (hours)         (s)
---------------------------------------------------------------
0.140           3.36            120        R         > 21.5

The probability of chance positional coincidence with a field star has 
been estimated to be approximately 0.06.

The above limit magnitude has been derived using the calibration provided
by Henden et al. (GCN 2844
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 )."

This message can be cited.

S. Bradley Cenko, Derek B. Fox, and Avishay Gal-Yam report on behalf of
the Caltech-NRAO-Carnegie GRB Collaboration:

"We have continued to monitor the SXC error circle of GRB041211 (H3622,
Dezalay et. al., GCN 2839
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 ) with the robotic Palomar 60-inch telescope.  We
obtained 40 x 120-s I-band exposures on the evening of December 12 (mean
time 07:37 UT, 19.9 h after the burst), followed by 20 x 120-s I-band
images on the evening of December 13 (mean time 06:55 UT, 43.2 h after
the burst).  Digital subtraction revealed no variable source in the SXC
error circle or its immediate surroundings.  The limiting magnitude of
our observations, estimated by comparison with the USNO-B1 catalog, is I
< 23.

No further observations are planned."

P. Wozniak, J. Wren, W.T. Vestrand, and R. White, report on behalf of
the RAPTOR team.
  
Stereoscopic observations collected by the RAPTOR wide-field sky
monitoring systems allow us to place optical limits on a prompt optical
flash from GRB 041211 (HETE trigger 3622). Five seconds after receiving
the initial HETE type 40 trigger, we began tiling around the nominal
HETE pointing direction. Our first image containing the GRB location
began at 11:34:09.93 UT (T+143.02s). This image was 10 seconds in
duration and reached an unfiltered limiting magnitude of 11.5. No new
object was detected within the error circle based on comparison to DSS
image. Later images reaching 15th magnitude also showed no new objects
compared to DSS images.

M.Sasaki, Y.Aita, T.Aoki, Y.Asaoka, M.Jobashi, N.Manago, K.Noda,
A.Okumura (ICRR,Univ.Tokyo), S.Ogawa (Toho Univ.), and H.Usami (Tohoku
Univ.), on behalf of the Ashra collaboration, report:

We have observed the field covering the WXM error box of GRB041211 with
the prototype unit of All-sky Survey High Resolution Air-shower
detector (Ashra, http://www.icrr.u-tokyo.ac.jp/~ashra) at the Haleakala
Observatory Site on Maui contimuously between 10:25 UT (1h7m before
GRB041211) and 13:13 UT (1h41m after GRB041211) on 2004-12-11. The
prototype unit utilizes a 11M-pixel CMOS sensor following a 0.4m
diameter image intensifier on a modified Baker-Nunn optical system with
0.6m diameter pupil and 1.2m projected diameter spherical reflector for
viewing a 50 degree circle region of sky. The achieved resolution is
2arcmin. We obtained about 2000 images covering the WXM error box of
GRB041211 every 5s with 4s exposure time respectively. The sensitive
region of wavelength is similar with the B-band. We detected no new
objects in the WXM error box. As a result of our preliminary analysis of
four sets of combined images, the following 3-sigma limiting magnitudes
are derived:

Time from GRB      ExpTime      Limit Mag.
(s)                (s)
----------------------------------------------------------------------
-1468 ~     0      1175         11.3
    0 ~   100        80         11.0
  100 ~  1000       720         11.5
 1000 ~  4035      2428         11.3
-----------------------------------------------------------------------

Limiting magnitudes were estimated by comparison with stars in Tycho-2
Catalog. 

Figures of limiting magnitudes vs time and so on may be found at:
http://www.icrr.u-tokyo.ac.jp/~ashra/GRB041211

This message may be cited.

C. Guidorzi, A. Monfardini, C.J. Mottram (Liverpool John Moores
University) and the Liverpool GRB team, on behalf of the larger Robonet
consortium, report:

"We obtained BVRI images of the SXC error box of GRB041211 detected
by HETE-II (GCN 2839
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 ) with the 2-m Faulkes Telescope North on Maui,
Hawaii.
Observations started on December 11.615 UT, i.e. 3.2 hours after the GRB
with an average seeing of 1.3 arcsec.
The robotic GRB pipeline did not find any new objects with reference
to USNOB, GSC2.3 and 2MASS catalogues.

Time from GRB   ExpTime    Filter    Limit Mag.
(days)          (s)
-----------------------------------------------
0.135           2x10         B       19.1
0.135           2x10         V       19.1
0.135           2x10         R       19.2
0.135           2x10         I       18.8
-----------------------------------------------

The above limit magnitudes have been derived using the calibration
provided by Henden et al. (GCN 2844
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 ).
After visual inspection of a 2 min R image taken soon after the
automatic sequence reported above, we do not find any new candidate
within the DSS limit.

This message can be cited."

A. Henden (USRA/USNO) reports on behalf of the USNO GRB team:

We have acquired BVRcIc all-sky photometry for
a 11x11 arcmin field centered on the SXC coordinates for the
HETE burst GRB041211 (trigger 3622; Dezalay et al., GCN 2839
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 )
with the USNOFS 1.0-m telescope on one photometric
night.  Stars brighter than V=13.5 are saturated and
should be used with care.  We have placed the photometric data
on our anonymous ftp site:
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb041211.dat
The astrometry in this file is based on linear plate solutions
with respect to UCAC2.  The external errors are less than 100mas.
The estimated external photometric error is about 0.02mag
and will be improved with additional calibration nights
if an afterglow is found.

As always, you should check the dates on the .dat file prior to
final publication to get the latest photometry.  There is
a README file on the ftp directory to give you information
about the procedures used to calibrate these fields.

E.Sonoda,S.Maeno,Y.Matsuo, M.Yamauchi
(University of Miyazaki)


"We have observed the field covering the SXC error box of
GRB041211(HETE trigger 3622; trigger time 11:31:47 UT ) with the
unfiltered CCD camera on the 30-cm telescope at University of
Miyazaki.The observation was started 12:52:07 UT on Dec.11.
Observed field of view is 43 arcmin centerd on
(06h 43m 09s , +20d 22' 35.5").
We have compared our images with the USNO A2.0 catalog .
Preliminary analysis shows there is no new source brighter than 17.2 mag.
in the SXC error box reported by HETE.  "

GRB 041211: Infrared Observations

C. H. Blake (CfA), J. S. Bloom (CfA; UCB), D. L. Starr (Gemini), M. F.
Skrutskie (U. Virginia), A. H. Szentgyorgyi (CfA), and E. E. Falco (SAO),
report:

"The 1.3m Peters Automated Infrared Imaging Telescope (PAIRITEL;
http://pairitel.org) at Mt. Hopkins, AZ was used to autonomously observe
the HETE-2 SXC error circle of GRB 041211 (Dezalay et al.; GCN #2839
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 ) in
the J,H,Ks near-infrared bands.  Approximately 30 minutes of observations
were made between 12-12-2004 05:03:00 UT and 12-12-2004 05:54:00 UT of a
10'x10' field centered on RA=06:43:12 DEC=+20:23:42 (J2000). We detect no
new sources within or around the SXC error circle to the limiting
magnitude of 2MASS (approximately J=16.4, H=16.3, Ks=15.7). We note that
this data was obtained with the same instrument and filter set as the
archival 2MASS Atlas images but are significantly deeper than the 2MASS
limit. We will continue to monitor this field."

A finding chart may be found at:
    http://pairitel.org/GRB041211

This message may be cited.

We are grateful for the assistance of the Mt. Hopkins Ridge staff. The
Peters Automated Infrared Imaging Telescope is operated by the Smithsonian
Astrophysical Observatory (SAO) and was made possible by a grant from the
Harvard University Milton Fund and the camera loan from the University of
Virginia.

W. Li, A. V. Filippenko, R. Chornock, and S. Jha (University of 
California, Berkeley) report:

"The Katzman Automatic Imaging Telescope (KAIT; see Li et al. 2003, 
PASP, 115, 844) at Lick Observatory robotically observed GRB 041211
(HETE Trigger #3622). One batch of 16 unfiltered images was taken
from 12:52:24 UT to 13:22:03 UT, covering a 12.6' x 12.6' field centered
on the WXM position R.A. = 06h43m53s, DEC = +20d 20'17" (J2000).
Another batch of 4 images was taken from 13:56:44 UT to 14:06:00 UT,
covering a 6.6' x 6.6' field centered on the revised WXM position 
R.A. = 06h43m27s, DEC = +20d 19'58" (J2000). We detected no new 
objects in our observations when compared to the DSS II images.
The following 3-sigma limiting magnitudes are derived (calibrated with 
USNO-A2.0 red magnitudes): R~17.1 mag for a 3 x 5s unfiltered grid image 
started at 12:52:24 UT (4837s after the burst), R~18.4 for a 60s
unfiltered image started at 12:59:20 UT (5253s after the burst)."

GRB 041211: Optical follow-up in East Asian region

S. Nishiura(Tokyo Gakugei Univ.), D. Kinoshita (NCU), C.L. Lu (BAO)  
K. Y. Huang (NCU), Y. Urata (RIKEN), Y. Qiu (BAO), 
on behalf of the East Asian collaboration report:

" We have imaged the entire GRB 041211 error circle (Dezalay et al. GCN 2839
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 ) at 
Kiso (Japan), Lulin (Taiwan) and XingLong (China) observatory.

The observations are summarized as below:

Start time(UTC) Filter Exposure (sec)  Limit mag.   Site
                                        (SN=3)
Dec. 11.55        Rc     300 x 1          >~18      Kiso
Dec. 11.63        R      300 x 3          >~20      Lulin
Dec. 11.63        R      300 x 1          >~20    XingLong

Limiting magnitudes were estimated by comparison with several USNO-B1.0
stars.  Comparison with DSS II images, no new object was detected down
to the limiting magnitude."

This message may be cited.

GRB 041211(=H3622):  A Long GRB Localized by the HETE WXM and SXC

J-P Dezalay, G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, and S. Woosley,
on behalf of the HETE Science Team;

T. Donaghy, E. Fenimore, M. Galassi, C. Graziani, M. Matsuoka,
Y. Nakagawa, T. Sakamoto, R. Sato, Y. Shirasaki, M. Suzuki,
T. Tamagawa, Y. Urata, T. Yamazaki, Y. Yamamoto, and A. Yoshida, on
behalf of the HETE WXM Team;

N. Butler, G. Crew, J. Doty, A. Dullighan, G. Prigozhin, R. Vanderspek,
J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga,
R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and
HETE Optical-SXC Teams;

C. Barraud, M. Boer, J-F Olive, and K. Hurley, on behalf of the HETE
FREGATE Team;

report:

The HETE FREGATE, WXM, and SXC instruments detected GRB 041211 (=H3622)
at 11:31:47 UT (41507 SOD) on 11 December 2004.  No prompt location was
issued because of a lack of real-time spacecraft aspect information.
Ground analysis of the WXM data produced a location that was reported
in a GCN Notice issued at 12:51:48 UT.  This localization can be
expressed as a circle of 8 arcminutes radius (90% confidence) that is
centered at

WXM-Ground:  RA = 06h 43m 53s, DEC =  +20d 20' 17" (J2000).

The WXM location was further refined, resulting in a new location that
was reported in a GCN Notice at 11:31:47 UT.  This localization can be
expressed as a circle of 8.6 arcminutes radius (90% confidence) that
is centered at

WXM-Ground:  RA = 06h 43m 27s, DEC =  +20d 19' 58" (J2000).

Ground analysis of the SXC data resulted in a location that was issued
in the same Notice as the refined WXM localization.  This localization
can be expressed as a circle of 80 arcseconds radius that is centered
at

SXC-Ground:  RA = 06h 43m 12s, DEC =  +20d 23' 42" (J2000).

The burst has a duration > 100 s.  Preliminary spectral analyses show
the 2-30 keV fluence of GRB 041211 to be 2.4 x 10-6 ergs cm-2 and the
30-400 keV fluence to be 1.0 x 10-5 ergs cm-2.  Therefore GRB 041211 is
a classical "hard" GRB.  The empirical redshift indicator for this
burst gives a pseudoZ~3.0.

A light curve, skymap, and spectral information for GRB 041211 are
provided at the following URL:

http://space.mit.edu/HETE/Bursts/GRB041211

This message may be cited.

Derek B. Fox reports on behalf of the Caltech-NRAO-Carnegie GRB
collaboration:  

"We have imaged the 80-arcsec radius SXC error circle of GRB041211
(HETE 3622) with the robotic Palomar 60-inch telescope, in a single
120-second exposure in Gunn i band at mean epoch 13:40:35 UT on
2004-12-11.  To a limiting equivalent magnitude of R~19 mag we detect
no new objects by reference to the Digitized Sky Survey (second
epoch).

Comparison of contemporaneous imaging of most of the rest of the
16-arcmin radius WXM error circle to the DSS has also not yielded any
optical afterglow candidates to this point."