GRB 041219

GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger

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

"Responding to the IBAS Alert #2073, we imaged the field of the (possible)
GRB 041219 starting at 19 Dec 2004 01h49m18 UT, about 2.8 minutes after
the GRB (imaging is on-going). A quick comparison with the 2MASS Quicklook
J-band images reveals no obvious new source. The imaging depth is deeper
than 2MASS. A more detailed analysis is on-going."

This message may be cited.

D. Gotz, S. Mereghetti (IASF, Milano), S.Shaw, M. Beck (ISDC, Versoix),
J.Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report:

A very long (about 9 minutes ) and bright GRB has been detected with the
INTEGRAL Burst Alert System (IBAS) on December 19 at 01:43 UT. The GRB has
been detected with IBIS/ISGRI in the 15-200 keV band (IBAS Alert # 2073).

Its coordinates (J2000)  are:

  RA:  6.1075 [degrees]
 DEC: +62.8349 [degrees]

with an uncertainty of 2 arcmin  (90% c.l. radius)

The brightest part of the burst saturated the available telemetry.
Therefore at the moment we can only estimate a lower limit to the peak
flux in the 20-200 keV range. This is about 12 photons/cmsq/s (1E-6
erg/cmsq/s) (1 s integration time).

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

"We have imaged the 2.5-arcmin radius error circle of the Integral GRB
041219 with the robotic Palomar 60-inch telescope.  Observations consisted
of 19 x 120-second exposures in the Kron I filter, commencing at 02:05:09
UT (~ 22 minutes after the burst).  To a limiting magnitude of I ~ 20 we
detect no new objects by reference to the Digitized Sky Survey (second
epoch).

Continued analysis and further observations are planned."

E. Rykoff (U. Michigan) and R. Quimby (U. Texas) report on behalf of the ROTSE
collaboration:

ROTSE-IIIb, located at McDonald Observatory, Texas, responded automatically to
INTEGRAL trigger #2073, GRB041219.  Our first 5-s exposure started at 01:44:11.6
UT, 74 seconds after the start of the GRB, and 6 seconds after the trigger, and
during the GRB itself (GCN 2866
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 ).  Our unfiltered images were calibrated
relative to USNO A2.0. Comparison to DSS reveals no new sources to a limiting
magnitude of around 17.2.  Due to the low galactic latitude, field crowding is
a significant issue. Imaging is ongoing.

GRB 041219: Infrared Afterglow Candidate

C. Blake (CfA) and J. S. Bloom (CfA/UCB) report on behalf of a larger
group:

"PAIRITEL continued to image the field of GRB 041219 (GCN #2866
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 ) starting
from 19 Dec 2004 01h49m18 UT, about 2.8 minutes after the GRB (see GCN
#2865
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 ). That first epoch of imaging had a total integration time of 533
sec. A second epoch of image began at 02h46m59 UT (502 sec total
integration). A comparison with the 2MASS Quicklook and Atlas K-band
images reveals a new point source at RA 00h24m27.6s, DEC +62d50m32.9s
(J2000).  By comparison to nearby 2MASS stars we estimate a magnitude of
K~15.5 in the first epoch. The object is also detected in J-band near the
detection limit (ie. it appears to be heavily reddened) and appears to
have faded between the two epochs.  Observations have ceased due to high
winds."

A finding chart will be posted shortly at:
   http://pairitel.org/grb041219.gif

This message may 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 coordinates for the
INTEGRAL burst GRB041219 (Gotz et al., GCN 2866
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 )
with the USNOFS 1.0-m telescope on one marginally photometric
night.  Stars brighter than V=13.0 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/grb041219.dat
The astrometry in this file is based on linear plate solutions
with respect to USNOA2.  The external errors are less than 300mas.
The estimated external photometric error is about 0.04mag
due to the poor seeing.

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.

GRB 041219: Infrared Afterglow Candidate

C. Blake (CfA) and J. S. Bloom (CfA/UCB) report on behalf of a larger
group:

"PAIRITEL continued to image the field of GRB 041219 (GCN #2866
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 ) starting
from 19 Dec 2004 01h49m18 UT, about 2.8 minutes after the GRB (see GCN
#2865
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 ). That first epoch of imaging had a total integration time of 533
sec. A second epoch of image began at 02h46m59 UT (502 sec total
integration). A comparison with the 2MASS Quicklook and Atlas K-band
images reveals a new point source at RA 00h24m27.6s, DEC +62d50m32.9s
(J2000).  By comparison to nearby 2MASS stars we estimate a magnitude of
K~15.5 in the first epoch. The object is also detected in J-band near the
detection limit (ie. it appears to be heavily reddened) and appears to
have faded between the two epochs.  Observations have ceased due to high
winds."

A finding chart will be posted shortly at:
   http://pairitel.org/grb041219.gif

This message may be cited.

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

At 01:42:18 UT, the Swift Burst Alert Telescope (BAT) triggered and
located on-board GRB041219 (GCN Circ# 2866, D.Gotz et al.).  The spacecraft
did not autonomously slew to the burst since automated slewing
is not yet enabled.

The BAT ground-calculated location is RA,Dec 6.154,+62.847 (J2000)
with an uncertainty of 12 arcmin (radius, including a large systematic
uncertainty due to the lack of an on-orbit bore-sight alignment calibration).
This is ~11 degrees off the BAT bore sight and is in the fully encoded
field of view.  This position is consistant with the INTEGRAL position
(GCN Circ# 2866), and is within 4.1 arcmin of the BAT on-board location
(14 sec after the initial rate trigger).  We note that this position
is in the Galactic plane with a Galactic Lon,Lat of 120,+0.1deg.

The burst lightcurve is multi-peaked with structure within the peaks.
After an initial pair of small precursors, the peak intensity increased
to 25 events/cm^2/sec (1-sec sampling; unsaturated; ~15 to 200 keV; 43 Crab)
300 sec after the initial triggering peak.  The total duration was 520 sec.
The fluence is ~1e-4 erg/cm^2.

Dae-Sik Moon, S. Bradley Cenko (Caltech), and Joe Adams (Cornell) report
on behalf of the Caltech-NRAO-Carnegie GRB Collaboration:

"We have imaged the field of  GRB041219 with the Wide Field Infrared
Camera (WIRC) on the Palomar 200-inch Hale Telescope.  We can confirm the
presence of a fading source at the position reported by Blake and Bloom
(GCN 2870
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 ).  Our K_s magnitudes (with reference to the 2MASS catalog) are
as follows:

UT (Dec 19)      t_burst       K_s Magnitude
----------------------------------------------------
02:31:52         0.8 h         14.9
03:16:01         1.55 h        15.5


This corresponds to a decay index of ~ 0.8"

A. M. Soderberg (Caltech) and D. A. Frail (NRAO) report on behalf
of the Caltech/NRAO/Carnegie GRB Collaboration:

"We observed the field of GRB 041219 (GCN #2866
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 ) with the
Very Large Array on 2004 Dec 20.14 UT (t ~ 1.1 days after the
burst).  At 8.5 GHz we detect a radio source coincident with
the optical afterglow reported by Blake & Bloom (GCN #2870
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 )
with a flux density of 0.45 +- 0.05 mJy.  Further observations
are planned."

-----------------------------------------------------------------
Alicia M. Soderberg	      	Office: 626.395.4095
Caltech Astronomy 	      	Mobile: 626.676.4723
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-----------------------------------------------------------------

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


"We have observed the field covering the error box of
GRB 041219 (INTEGRAL trigger 2073; trigger time 01:42:54.79 UT)
with the unfiltered CCD camera on the 30-cm telescope
at University of Miyazaki.
The observation was started 11:17:21 UT on Dec.19.
Observed field of view is 43 arcmin centerd on
R.A=00h 23m 41.32s
Dec=+62d 54m 13.0s
After co-adding a set of 5 images of 30 sec exposures ,
we have compared with the USNO A2.0 catalog . Preliminary analysis
shows there is no new source brighter than 18.5 mag.
at the position reported by C.Blake et.al.(GCN2872
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 )."

Dae-Sik Moon, S. Bradley Cenko (Caltech) and Joe Adams (Cornell) report on
behalf of the Caltech-NRAO-Carnegie GRB Collaboration:

"We have continued to image the NIR afterglow of GRB041219 (Blake and
Bloom, GCN 2870
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 ) with the Wide Field Infrared Camera (WIRC) on the Palomar
200-inch Hale Telescope.  Our latest observations in the K_s
band, taken at a mean time of 01:58:00 UT (1.01 days after the burst), put
the object at a magnitude of 16.5 (with reference to the 2MASS catalog).
This is a significantly shallower decay than we reported for the early
afterglow (GCN 2876
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 ).

Further observations are planned."

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

"We have imaged the position of the NIR afterglow of GRB041219 (Blake and
Bloom, GCN 2870
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 ) with the robotic Palomar 60-inch telescope.  We detect
the presence of a faint source at this position, with a z-band magnitude
of 21.0 +/- 0.3.  The mean epoch of our observations is approximately
04:57 UT, December 20.

Further observations are planned."

S. B. Pandey and Kuntal Misra (ARIES NainiTal), on behalf of
larger Indian GRB collaboration

We observed INTEGRAL/Swift GRB 041219 localization by Gotz et al. (GCN 
2866
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 ) with 1.04m telescope at ARIES NainiTal. In a single 900 sec R_c 
band frame, we did not detect the optical afterglow at the IR afterglow 
position of the source by Blake & Bloom (GCN 2870
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 ). We put an upper 
limit ~ 21 mag, around 13 hours after the burst.

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J. Wren, W. T. Vestrand, S. Evans, R. White, and P. Wozniak
report on behalf of the RAPTOR team at Los Alamos National Lab.

The RAPTOR-S telescope responded robotically to INTEGRAL trigger
#2073.  Our first image began at 01:44:13.65 UT, 8 seconds after
receipt of the Integral notice and while the GRB was still ongoing.
Summing our images over the duration of the GRB emission (1:44 UT to
1:52 UT), we marginally detect a possible source very close to our
threshold at the location of the candidate given by Blake and Bloom
(GCN 2870
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 ).  Interpreted as an upper limit, these observations
indicate the prompt optical emission remained fainter than R=19.4.
A RAPTOR finder chart can be found at
http://www.raptor.lanl.gov/grb041219/.

GRB 041219 : optical follow-up observations

C.W. Chen (NCU), H.C. Lin (NCU), C.L. Lu (BAO)
K.Y. Huang (NCU), Y. Qiu (BAO), Y. Urata (RIKEN), Y.Q. Lou(THCA) 
on behalf of the East Asian collaboration report:
 
" We have observed the position of infrared afterglow candidate
reported by Blake et al. (GCN 2870
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 ) at Lulin (Taiwan, 1-m telescope)
and XingLong (China, 0.8 m telescope) Observatory. The R band
observations are summarized as below:

 Start Time (UTC)   Filter      Exposure (sec)  Limit mag.   Site
                                                 (SN=3)             
  Dec. 9.47           R       300 x 2 + 600 x 2   >~ 21      Lulin
  Dec. 9.48           R       300 x 1 + 360 x 1   >~ 20      XingLong
 
Limiting magnitudes were estimated by comparison with several
USNO-B1.0 stars. The candidate was not detected brighter than the
limiting magnitudes."

This message may be cited.

GRB 041219: Keck IR Observations and Astrometric Refinement of the IR Flash

J. S. Bloom (CfA/UCB), J. X. Prochaska (UCSC), C. McCabe (UCLA),
A. Ghez (UCLA), K. Stapelfeldt (JPL), G. Duchene (Grenoble),
Q. Konopacky (UCLA), K. Hurley (UCB/SSL), C. Blake (CfA), D. Starr
(Gemini) report:

Comparing the IR flash discovery images (GCN #2870
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 ) of GRB 041219 (GCN
#2866
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 ; #2874) to 25 stars in the 2MASS catalogue, we find a refined
absolute astrometric position of the IR flash to be (J2000):

   RA = 00:24:27.68 (+/- 0.124"), Dec = +62:50:33.501 (+/- 0.228")

This is 4.310" East and 8.415" North from a nearby brighter point source.

In J-band imaging (though clouds) with NIRC on the Keck I 10-m
telescope on Mauna Kea, HI, the IR transient (IRT) was detected on
20.25 December 2004 UT, significantly faded from the first night of
PAIRITEL imaging. In 0.7" seeing, the IRT appears point-like; that is,
there is no indication yet for the presence of an underlying host
galaxy. We note that the IRT is located 2.5 arcsec south-south-west of
a faint compact source."

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A.J. van der Horst (University of Amsterdam), E. Rol (University of
Leicester) and R. Strom (ASTRON, University of Amsterdam) report on behalf
of a larger collaboration:

"We observed the INTEGRAL GRB 041219 (GCN 2866
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 ) at 4.9 GHz with the
Westerbork Synthesis Radio Telescope on December 20 from 15.55 to 23.59
UT, i.e. 1.59 - 1.93 days after the burst.
We detect a radio source at the position of the infrared afterglow
reported by Bloom et al. (GCN 2893
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 ) with an average flux density of 205
+/- 20 microJy,
and a probable increase in the flux density during the observation.
This measurement is in agreement with the radio detection at 8.5 GHz
reported by Soderberg & Frail (GCN 2881
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 ).

Further observations are planned."

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A.J. van der Horst (University of Amsterdam), E. Rol (University of
Leicester) and R. Strom (ASTRON, University of Amsterdam) report on behalf
of a larger collaboration:

"We reobserved the INTEGRAL GRB 041219 (GCN 2866
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 ) at 4.9 GHz with the
Westerbork Synthesis Radio Telescope on December 21 from 14.45 to 23.55
UT, i.e. 2.54 - 2.93 days after the burst.
Compared to our previous measurement (GCN 2894
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 ), the average flux density
has increased to 349 +/- 22 microJy.
Assuming a power law behaviour, the average temporal index at 4.9 GHz
between this and our previous observation is alpha ~ 1.2.

Further observations are planned."

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Klotz, A., Boer M. (OHP), Atteia, J.L., and G. Stratta (LATT) report

The field of GRB 041219 (Mereghetti, et al., GCNC 2866) was observed with
the robotic 25 cm TAROT telescope at Calern, France.
The observation started 25 seconds after the GCN notice without filter. The
field was only 28 degrees above horizon.

We co-added 12 frames of 30s from 01:45:30 to 01:54:05 UT, i.e. while the
GRB prompt emission was still active. The associated OT described by Blake &
Bloom (GCNC 2870) is not detected at the limiting magnitude of the image R >
18.5.

We analyzed the 2MASS catalog to extract the galactic extinction through the
line of sight of GRB041219. We used the method described in Klotz et al.
(A&A 2004, vol 425, p427). From Earth to a distance modulus of about 10.5,
the visual extinction is Av=1.12. The 2MASS data don't allow probing farer
distances.

This message can be cited.

E. Fenimore (LANL), S. Barthelmy (GSFC), J. Cummings (GSFC), N. Gehrels
(GSFC), D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA), C. Markwardt (UMD),
K. McLean (LANL), D. Palmer (LANL), A. Parsons (GSFC), J. Tueller (GSFC)  
on behalf of the Swift BAT team.

The INTEGRAL-Swift Burst of 041219 (GCN 2866
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 , Gotz et al, GCN 2874
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 ,
Barthelmy et al.) had a time history that is rather rare: a precursor was
followed by 200 sec of mostly quiet emission before a huge spiky outburst
that lasted an additional 300 sec. This is one of the few events for which
there have been simultaneous ground observations. It is the first event
with simultaneous IR observations (GCN 2870
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 , Blake and Bloom) and there
has been a near-threshold detection in the optical (GCN 2889
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 , Wren et
al.). Given the large interest in this burst and the scientific value of
combining the simultaneous gamma-ray and ground observations, we provide
at the web site below the GRB041219 4-channel data (15-25 keV, 25-50 keV,
50-100 keV, 100-350 keV) for -341 s before to +558 s after the BAT trigger
with 0.064 s resolution. Provided are figures for each energy band, the 15
- 350 keV energy band, and a text table of the data. We have not corrected
for the deadtime. Testing has shown that our saturation level is > 1E6 Hz,
so we were orders of magnitude below our saturation limit.

The background was very smooth before the event and, apparently, also
within the 8 minute long burst. Beyond 560 s after the trigger, there is a
long smooth increase in the count rate, but it does not image to a point
source, so it is probably due to trapped radiation. We used 300 s of data
ending at 41 s before the trigger to determine background. Many features
are common to other GRBs: peaks that are narrower at higher energy, peaks
with FWHM of ~ 1 s, and a general softening of the event with time. Time in
the figure is from the BAT initial trigger at 6138.68 UT. BAT located
the event 14 s later, at which time Swift would have slewed XRT and UVOT
as well as sent out a TDRSS notice if slewing and TDRSS messages had been
enabled.

See http://gcn.gsfc.nasa.gov/gcn/other/041219_swift_bat.html

NIR Observations of GRB 041219

F. Hearty (Colorado), D. Q. Lamb (Chicago), J. Barentine (APO), P. A.
Price (Hawaii), S. Beland (Colorado), E. L. Turner (Princeton), R.
McMillan (APO), J. Dembicky (APO), B. Ketzeback(APO), and D. G. York
(Chicago) report on behalf of the ARC team of the FUN GRB
collaboration:

We observed the NIR afterglow (Blake and Bloom, GCN Circular No. 2870)
of GRB 041219, a burst localized by Integral (Gotz et al., GCN Circular
No. 2866) and Swift-BAT (Barthelmy et al., GCN Circular No. 2874), on
the night of December 20th, using C-NIC (formerly NIC-FPS) on the ARC
3.5-meter telescope at Apache Point Observatory.  The observation began
at 01.05 UT, 47.25 hours after the burst, and consisted of a series of
120, 20, and 20-second exposures in J, H, and Ks, respectively.  We
constructed stacked images corresponding to 20-minute exposures in J
and H, and a 40-minute exposure in Ks.  We detect the afterglow in all
three filters; the magnitudes are J = 19.9 +/- 0.2, H = 18.9 +/- 0.1,
and Ks = 17.6 +/- 0.2.  We thus confirm that the afterglow is heavily
reddened, as previously noted by Blake and Bloom (GCN Circular No.
2870).  We also confirm that the afterglow had faded significantly in
comparison with the earlier NIR observations reported by Blake and
Bloom (GCN Circular No. 2870) and Moon, Cenko, and Adams (GCN Circular
Nos. 2876 and 2884), in agreement with the conclusion of Bloom et al.
(GCN Circular No. 2893).  As noted by Bloom et al. (GCN Circular No.
2893), the IR afterglow is located 2.5 arcseconds south-south-west of a
faint compact source that is visible in J, H, and Ks.

Using Schlegel et al. (1998), the estimated extinction in the direction
of GRB 041219 is E(B-V) = 1.8 mag, corresponding to A_lambda values of
J = 1.6, H = 1.0, K = 0.65 mag.  These values give J-H = 0.6, H-K =
0.4, and  J-K = 1 mag, compared to our measured values of J-H = 1.0,
H-K = 1.3, and J-K = 2.3 mag.  Although our results indicate greater
reddening than that estimated using Schlegel et al. (1998), the
estimated value of E(B-V) is unreliable because GRB 041219 lies very
close to the Galactic plane (b = 0.6 [deg]).  We therefore cannot say
that there is more reddening than can be accounted for by Galactic
extinction.  However, our results show that the drop-off with
decreasing wavelength is gradual and therefore is unlikely to be due to
absorption by hydrogen in the host galaxy or along the line of sight to
the host galaxy.  Consequently, the burst is unlikely to lie at a very
high redshift (z > 5).

This message may be cited.

Alan Levine and Ron Remillard (MIT) on behalf of the RXTE ASM Team
at MIT and GSFC:

GRB041219 (Mereghetti et al., GCN Circular 2866
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 ; and Barthelmy et al.,
GCN Circular 2874
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 ) was observed during two dwells, each of duration 90
s, with Scanning Shadow Camera 3 of the RXTE ASM.  The observations
cover the interval 2004 December 19 1:42:24 to 1:45:30 UTC except for
a single 6 s gap in the middle of the interval.  Automated real-time
analysis of RXTE ASM data yielded a detection of GRB041219 and an
error box:

RA, Dec (error box center; J2000):      7.085   62.727 degrees
Position angle of the error box long direction): 105.72 degrees
Error box half width:      0.037 degrees
Error box half length:      0.7 degrees

in which is found the position derived by Bloom et al. (GCN Circular
2893
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 ).

In count rate data, the event appears as a single peak with possible
substructure lasting about 50 s in the 1.5-3 keV and 3-5 keV bands and
about 25 s in the 5-12 keV band.  The peak fluxes were approximately
3, 4 and 6 Crab in the 1.5-3, 3-5, and 5-12 keV bands, respectively.
The initial sharp rise of this peak (best defined in the 5-12 keV
band) occurs at UTC 2004:354:01:43:30 with an uncertainty of about 2
seconds.  The background before this time appears to vary; this could
be the tail of an earlier GRB-related peak or it could be variation of
an unrelated source.  The times quoted herein are times at the
position of the spacecraft; they have not been corrected to the
barycenter of the solar system.

In the time interval covered by the ASM, the Swift BAT light curves
(Fenimore et al., GCN Circular 2906
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 ) show a single relatively
inconspicuous small enhancement that appears to start at about the
same time as the peak seen in the ASM data. The ASM coverage does not
cover the first peak seen by BAT or the later strong peaks.

This message is citeable.

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

In addition to the BVRcIc calibration, we also acquired
some early time, short exposure Rc and Ic imagery for the
INTEGRAL burst GRB041219 (Gotz et al., GCN 2866
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 )
with the USNOFS 1.0-m telescope.  At the position of
the NIR afterglow (Blake and Bloom, GCN 2872
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 ), we
find no optical afterglow in the Ic bandpass at
t+13minutes, to a limit of Ic=19.7.