GRB 041217

D. T. Durig (Cordell-Lorenz Observatory, Sewanee, TN, USA) reports on behalf of 
the AAVSO International High Energy Network:

Observations of the Swift error circle for GRB041217 (Palmer et al., GCN 2853
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 ) 
were made with the Cordell-Lorenz Observatory 0.30m telescope + unfiltered CCD.

Eighteen 300-second exposures with UT midpoint of 2004-12-18T10:36 (1.1 days
after the burst) and twentythree 300-second exposures with UT midpoint of 
2004-12-20T10:26 (3.1 days) were stacked, with limiting sigma-3 magnitudes of 
20.0CR and 20.3CR based on USNOA2.0.  

The 47 arcmin x 47 arcmin field was centered at 10h 59m 53s -17d 51' 45" 
(J2000.0), covering all of the error circle. 

No new object is seen down to approximately CR=20.0 when comparing
against a DSS2-R image. 

The four candidates of Berger & Gonzalez (GCN 2859
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 ) are visible on both epochs 
but don't show significant fading.

Examing the images of the two epochs gives lower limit for an afterglow about 
20.0CR 1.1 days after the burst.

The combined FITS images can be found at:

ftp://ftp.aavso.org/grb/Dr.DougDurig_GRB041207_2453360.03964_.fits 
ftp://ftp.aavso.org/grb/Dr.DouglasT.Durig_GRB041217_2453358.03701_.fits 


The AAVSO International GRB network is greatful for a generous grant
from the Curry Foundation and to NASA for the financial support for the
High Energy Astrophysics Workshops for Amateur Astronomers.

Matt Bayliss, Melissa Nysewander, Andrew Foster, Dan Reichart, and Jane
Moran report on behalf of the U. North Carolina team of the FUN GRB
Collaboration:

We imaged an 11.7 arcmin x 11.7 arcmin field near the center of the
localization of GRB 041217 (Palmer et al., GCN 2853
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 ) for 96 x 60 sec in Rc
beginning 22.7 hours after the burst with PROMPT Telescope 5 at CTIO.

Visual comparison to POSS2-Red reveals no obvious transients, however our
image goes deeper.  Calibration to 6 USNO-A2.0 stars yields a 3-sigma
limiting magnitude of Rc = 21.5 at a mean time of 23.8 hours after the
burst for this region.  Only the first candidate of Berger & Gonzalez (GCN
2859
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 ) would lie in our field, but we find nothing at this location.  Our
image can be found at:

http://www.physics.unc.edu/~mnysewan/grb041217.html

PROMPT is very early into construction and commissioning.  Enclosure
construction began in September 2004:

http://www.physics.unc.edu/~evans/promptcam/promptcam.html

Construction and commissioning of the first two telescopes began only two
and a half days prior to this burst.  All six telescopes will be completed
and upgraded to 0.41m Ritchey-Chretien telescopes by mid-2005.  For more
information on PROMPT:

http://www.physics.unc.edu/~reichart/prompt.html

M.Cwiok, K.Krupska, K.Kwiecinska, L.Mankiewicz, K.Nawrocki,
B.Pilecki, L.W.Piotrowski, G.Pojmanski, M.Sokolowski, D.Szczygiel,
G.Wrochna, on behalf of "Pi of the Sky / ASAS" collaboration
http://grb.fuw.edu.pl

The GRB 041217 (GCN 2853
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 ) error box was observed by "Pi of the Sky"
apparatus at Las Campanas Observatory at 7:58 UT, i.e. 30 minutes
after the GRB. 3 exposures, 10s each, have been taken by 2 cameras.
No new object has been found within the SWIFT error box.
The limiting magnitude on 3 coadded frames is 11.5m,
however, the object could be hidden in the glow of alpha Crt.
More information at http://grb.fuw.edu.pl/pi/ot/grb041217/

E. Berger (Carnegie Observatories) and S. Gonzalez (Las Campanas
Observatory) report:

"We imaged the 12-arcmin radius error circle of GRB 041217 (GCN 2853
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 ) with
the Swope 40-inch telescope at Las Campanas Observatory starting on
December 18.304 (nearly 24 hours after the burst) in r-band for a total of
12 minutes.  A comparison to DSS reveals no new bright objects.  However,
four faint objects close to the detection limit of the DSS are detected
with no counterparts in the DSS.  We urge other observers to examine their
images at the positions of these four candidates:

Can-1:
        RA = 10:58:44.19
        DEC= -17:49:34.6

Can-2:
        RA = 10:59:38.06
        DEC= -17:53:02.0

Can-3:
        RA = 10:59:15.55
        DEC= -18:05:35.6

Can-4:
        RA = 10:59:06.83
        DEC= -18:06:58.2

Continued observations are planned."

G. G. Williams (MMTO), F. Yoshida, T. Ito (National Astronomical
Observatory of Japan)
                                                                                
We observed a 25 x 25 arcmin area centered on the coordinates of the Swift
GRB 041217 (GCN 2853
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 ) with the 90prime instrument on the Steward
Observatory 90-inch Bok telescope.  Two 300s R-band images were obtained
beginning on Dec. 18 at 11:55:56 UT.  We do not find any new objects down
to the limiting magnitude of the DSS.
                                                                                
Further analysis and additional observations are planned.

Testa V., Tosti G., Monfardini A., Covino S., Tagliaferri G.,
Chincarini G., Zerbi F., Molinari E., Di Paola A., Rodono' M.,
Antonelli L.A., Conconi P., Cutispoto G., Nicastro L., Palazzi E.,
on behalf of the REM/ROSS team.

We imaged in the NIR and optical bands with the REM 60cm robotic
telescope at ESO-La Silla the central field of GRB041217, detected
by the Swift Burst Alert Telescope (D. Palmer et al. GCN 2853
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 ). The
observations were carried out on 2004, December 18, from 05:28 to
06:00 UT (i.e. 22 hours after the burst, as soon as the field was visible
from the telescope site), with the REMIR near-IR camera (10x10 arcmin
FOV, JHK filters) and with the ROSS spectrograph/imager in the
optical (10x10 arcmin FOV, VRI filters).

The observations were carried out under good seeing conditions, but
with an airmass of about 2. The total exposure times were of J: 600s,
H: 600s, K: 300s,V: 120s, R: 120s and I: 120s.

The comparison with the 2MASS catalog did not reveal new IR sources at
the limit of the catalog. Also the optical observations did not show any
plausible candidates. New observation are planned for tonight.

This message is citeable.

S. Bradley Cenko reports on behalf of the Caltech-NRAO-Carnegie GRB
Collaboration:

"We have imaged the entire 12-arcmin radius error circle of the Swift GRB
041217 with the robotic Palomar 60-inch telescope.  Observations consisted
of 25 x 120-second exposures in the Gunn g and Kron I filters.  High winds
led to extremely poor seeing conditions (~ 3-arcsec average).  To a
limiting magnitude of I~19.5 we detect no new objects by reference to the
Digitized Sky Survey (second epoch).

Continued analysis and further observations are planned."

GRB041217: Infrared Observations

J. S. Bloom (CfA/UCB) reports on behalf of a larger group:

"We observed a ~30 arcmin x 30 arcmin field about the Swift localization
of GRB 041217 (GCN #2853
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 ; Palmer et al. 2004) with the 1.3m PAIRITEL
system at Mt. Hopkins, AZ.  In poor seeing conditions, a total of 371
images (in J, H, and K bands) of 7.8 sec integration time (8.5 arcmin FOV)
were acquired from 2004 Dec 18 10h47m21s to 13h20m33s UT. A preliminary
comparison of the central ~8 arcmin surrounding the Swift position with
the 2MASS Quicklook catalog image position reveals no new objects to the
2MASS detection level in J-band. A more complete analysis is on-going."

More information on the PAIRITEL system may be found at
http://pairitel.org. We thank J. Huchra for assistance on the mountain.

This message may be cited.

D. Palmer (LANL), E. Fenimore (LANL), S. Barthelmy (GSFC), G. Chincarini
(OAB), J. Cummings (GSFC), N. Gehrels (GSFC), P. Giommi (ASDC), M. Goad
(U.Leicester), D. Hullinger (UMD), H. Krimm (USRA), C. Markwardt (UMD), K. Mason
(MSSL), K. McLean (LANL), J. Nousek (PSU), J. Osborne (U.Leicester), A. Parsons
(GSFC), G. Sato (ISAS), M. Suzuki (Saitama), J. Tueller (GSFC), A. Wells
(U.Leicester), N. White (GSFC), on behalf of the Swift BAT team.

On Dec 17 2004, 7:28:30 UT, the Swift Burst Alert Telescope (BAT)  
triggered and located on-board an apparent gamma-ray burst. The
spacecraft did not autonomously slew to the burst since automated slewing
is not yet enabled.

The location is RA/Dec 164.79, -17.95 (J2000). This is about 42 degrees off the
bore sight in the partially encoded field of view. The Swift attitude
control system is still undergoing calibration, but we estimate that the
position is within 12 arcmin (radius). The on-orbit location differed from a
location processed on the ground by about 6 arcmin. After 
calibration we expect on-board locations to be within 4 arcmin.

The burst can be characterized as a smooth profile with a rise time of
2 sec and a fall time of 6 sec. The T90 was ~6.7. Although BAT is still
undergoing calibration, ground processing gives a power law spectrum with
a number index of -1.6 and a fluence of 5E-6 erg/cm^2 in the ~20 to 200
keV range. The peak was about 4.4 cts/cm^2/sec in ~15 to 200 keV.

[GCN OPS NOTE (18-19dec04): "UL" was changed to "U.Leicester".  And the words
"(J2000)" and "(radius)" were added to the position estimate.]