GRB 040422

Y.Qiu and J.Hu (NAOC) report:

We observed the erro box of GRB040422 with the 0.8 m telescope at  Xinglong
Observatory, National Astronomical Observatories of China, at 18.24 UT April 
22.

Four unfiltered images  were taken with exposure time 300s. Comparing with
DSS-II image, we couldn't find any new source in the combined image.
The limiting magnitude of the combined image is about 20.0.

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V.Rumyantsev (CrAO) and A.Pozanenko (IKI) report:

We have observed the error box of GRB 040422 (INTEGRAL trigger 1758,
GCN2572
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 , Mereghetti et. al) with 2.6 m Shajn telescope (F/3.9) at Crimean
Astrophysical Observatory. The observation start (UT) Apr. 22, 23:37  under
poor sky conditions (seeing ~2.5 arcsec).

Several R-images taken between (UT) Apr. 22, 23:37 - Apr. 23, 01:39 with
exposition 120 s of each frame covered 60% of the GRB error box. Comparison
with DSS2 reveals no new objects brighter than limits of DSS2. The limiting
magnitude of co-added images is ~21R.

Combined mosaic image of GRB error box can be found at
http://grb.rssi.ru/GRB040422

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A.Piccioni, C.Bartolini, A.Guarnieri (Bologna University), P.Ferrero,
G.Pizzichini (IASF-CNR, Sezione di Bologna), and I. Bruni (Bologna
Observatory) report:
 
  We have observed the error box of GRB040422 (INTEGRAL trigger
1758; GCN 2572
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 , Mereghetti et al.) with the 152 cm Loiano Telescope
and the BFOSC camera system on April 22, in non perfect sky
conditions (seeing ~ 2 arcsec).
Two 600s Rc images have been obtained at 23.092 and 23.099 UT
respectively (exposition start epochs).
By comparison of the coadded images with the DSS2 catalog we do
not identify any obvious source.
Our limit magnitude, estimated by PSF photometry, results to be
approx 20.1.
Coadded images, observation log and a short comment can be
retrieved by sftp at ermione.bo.astro.it, username: publicGRB,
password: GRB_bo, directory: GRB040422.

GRB040422 : I-band follow-up observation at Lulin Observatory

M.K.Yang, K.Y.Huang, W.H. Ip (NCU)
Y. Urata and T. Tamagawa (RIKEN) report:

" We observed the whole field of INTEGRAL error circle of GRB040422
with 1-m telescope at Lulin Observatory at 16.5 UT April 22 ( about
9.6 hr after the burst). There are four images taken at I band images with
exposure time 300 sec.

  There are no new source was found by comparing DSS-II I band
image. The limiting magnitude is 19.7 mag ( SN=3, with USNO-A2.0 red
magnitude).

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E. Rykoff reports on behalf of the ROTSE collaboration:

The ROTSE-IIIb robotic telescope at McDonald Observatory, Texas, 
responded automatically to INTEGRAL Trigger #1756 (GRB040422) within 8 s 
of the receipt of the first alert, and 22.1 s after the beginning of the 
GRB.  Our response sequence consists of 10 5 s exposures, 10 20 s 
exposures and 200 60 s exposures, all unfiltered.

As the burst was behind the galactic plane, we expect significant 
extinction in our optical passband.  Applying the formula from 
Finkbeiner, Schlegel and Davis (1998), we expect 4.4 magnitudes of 
extinction in the R-band, although they give a caveat that their 
calculations "should not be trusted" at galactic latitudes of |b|<5.

Our first 5-s exposure started at 06:58:27.21 UT.  We visually compared 
our images to the DSS using the revised error circle as reported by 
Mereghetti et. al (GCN 2572
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 ).  We find no objects absent from the DSS to 
a limiting magnitude of R ~ 16.5, although field crowding creates 
significant source confusion.  Coadding our first 10 images, with an 
effective exposure time of 110 s, also does not reveal any new objects 
to a limiting magnitude of R ~ 17.5.

Furthermore, no objects in the error box varied significantly over the 
course of our 3.7 hours of observation.

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

We have acquired shallow BVRcIc all-sky photometry for
a 11x11 arcmin field centered on the INTEGRAL coordinates
(Mereghetti et al. GCN 2572
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 ) for GRB040422
with the USNOFS 1.0-m telescope on one marginal night.
Stars brighter than V=12.5 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/grb040422.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 0.03mag
and will be improved with additional calibration nights
if an afterglow is discovered.

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.

S.Maeno, E.Sonoda, M.Yamauchi
(University of Miyazaki)
"We have observed the field covering the error box of
GRB 040422 (INTEGRAL trigger 1758; trigger time 07:45:27 UT) with the
unfiltered CCD camera on the 30-cm telescope at University of
Miyazaki.The observation was started 14:06:55 UT on Apl.22. 
Observed field of view is 43 arcmin centerd on R.A=18,41,38
Dec=+02,04,20d. 
After co-adding a set of 2 images of 30 sec exposures ,
we have compared with the USNO A2.0 catalog . Preliminary analysis
shows there is no new source brighter than 16.94 mag.
in the GRB error box  reported by INTEGRAL.  "

D. Malesani (SISSA, Trieste), D. Fugazza, G. Ghirlanda (INAF, Brera), on 
behalf of a larger international collaboration involved in the Swift 
mission, report:

We observed the error box of the INTEGRAL GRB040422 (Mereghetti et al., 
GCN 2572
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 ), starting 2 hours after the burst. Observations were performed 
at ESO-Paranal, with an excellent seeing of ~0.5". Optical photometry 
(in the R and I filters) were acquired with VLT+FORS2, while NIR K-band 
imaging was performed with VLT+ISAAC. Four exposures were needed to 
cover the entire INTEGRAL error box in the infrared.

We find no obvious sources after comparison of our images with the 2MASS 
catalog. The limit for the 2MASS is estimated to be K < 14.5 (Skrutskie 
2001, AAS #198, 33, 827). We estimate our limiting magnitude to be K = 
18.5 based on the 2MASS calibration.

Further observations are planned tonight at ESO, in order to search for 
variable sources. Our images are available upon request.

We thank the ESO staff at Paranal, and in particular Nancy Ageorges and 
Leonardo Vanzi, for quickly performing the observations.

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S. Mereghetti, D. Gotz (IASF, Milano), J. Borkowski, M. Beck (ISDC) on
behalf of the IBAS Localization Team, S. Shaw and R. Walter on behalf of
the INTEGRAL Science data Centre (ISDC) and the INTEGRAL Science Working
Team report:

An 8 s long GRB has been detected with the INTEGRAL Burst Alert System
(IBAS) on April 22 at 06:58:02 UT. The GRB has been detected with
IBIS/ISGRI in the 15-200 keV band. Its coordinates (J2000)  are:

R.A.  18h 42m 00s
Dec. +01deg 59' 29''

with an uncertainty of 2.5 arcmin.

The preliminary peak flux in the 20-200 keV range is about 2.7
photons/cmsq/s (2.5 x 10^-7 erg/cmsq/s) (1 s integration time).

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