Gamma-ray Burst 030429

(All information courtesy of the instrument teams.)

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:          GCN/HETE BURST POSITION NOTICE
NOTICE_DATE:    Tue 29 Apr 03 10:44:02 UT
NOTICE_TYPE:    HETE S/C_Alert
TRIGGER_NUM:    2695,   Seq_Num: 1
GRB_DATE:       12758 TJD;   119 DOY;   03/04/29
GRB_TIME:       38542.69 SOD {10:42:22.69} UT
TRIGGER_SOURCE: Trigger on the 25-400 keV band.
WXM_SIG/NOISE:  0.1 sig/noise  on a 6.720 [sec] timescale
SC_-Z_RA:       193 [deg]
SC_-Z_DEC:      -10 [deg]
SC_LONG:        174 [deg East]
SUN_POSTN:       36.33d {+02h 25m 20s}  +14.41d {+14d 24' 22"}
MOON_POSTN:      16.28d {+01h 05m 06s}   +3.05d {+03d 02' 42"}
MOON_ILLUM:     4 [%]
COMMENTS:       Probable GRB.

GCN/BACODINE POSITION NOTICE

TITLE:          GCN/HETE BURST POSITION NOTICE
NOTICE_DATE:    Tue 29 Apr 03 12:34:28 UT
NOTICE_TYPE:    HETE Ground Analysis
TRIGGER_NUM:    2695,   Seq_Num: 3
GRB_DATE:       12758 TJD;   119 DOY;   03/04/29
GRB_TIME:       38542.68 SOD {10:42:22.68} UT
TRIGGER_SOURCE: Trigger on the 25-400 keV band.
WXM_SIG/NOISE:  0.1 sig/noise  on a 6.720 [sec] timescale
SC_-Z_RA:       192 [deg]
SC_-Z_DEC:      -10 [deg]
SC_LONG:        174 [deg East]
WXM_CNTR_RA:    183.325d {+12h 13m 18s} (J2000),
                183.367d {+12h 13m 28s} (current),
                182.678d {+12h 10m 43s} (1950)
WXM_CNTR_DEC:   -20.853d {-20d 51' 09"} (J2000),
                -20.871d {-20d 52' 15"} (current),
                -20.575d {-20d 34' 28"} (1950)
WXM_CORNER1:    183.3850 -21.0320 [deg]
WXM_CORNER2:    183.2080 -20.9990 [deg]
WXM_CORNER3:    183.2640 -20.6740 [deg]
WXM_CORNER4:    183.4410 -20.7060 [deg]
WXM_MAX_SIZE:   22.52 [arcmin] diameter
WXM_LOC_SN:     6 sig/noise (pt src in image)
WXM_IMAGE_SN:   X= 7.3 Y= 4.0 [sig/noise]
WXM_LC_SN:      X= 11.3 Y= 7.9 [sig/noise]
SXC_CNTR_RA:    183.276d {+12h 13m 06s} (J2000),
                183.319d {+12h 13m 17s} (current),
                182.630d {+12h 10m 31s} (1950)
SXC_CNTR_DEC:   -20.933d {-20d 56' 00"} (J2000),
                -20.952d {-20d 57' 06"} (current),
                -20.655d {-20d 39' 19"} (1950)
SXC_MAX_SIZE:   2.00 [arcmin] diameter
SXC_LOC_SN:     6 sig/noise (pt src in image)
SUN_POSTN:       36.33d {+02h 25m 20s}  +14.41d {+14d 24' 22"}
SUN_DIST:       147.93 [deg]
MOON_POSTN:      16.28d {+01h 05m 06s}   +3.05d {+03d 02' 42"}
MOON_DIST:      158.10 [deg]
MOON_ILLUM:     4 [%]
GAL_COORDS:     291.03,41.05 [deg] galactic lon,lat of the burst
ECL_COORDS:     191.58,-17.85 [deg] ecliptic lon,lat of the burst
COMMENTS:       Definite GRB.
COMMENTS:       SXC error box is circular; not rectangular.
COMMENTS:       The WXM & SXC positions are consistant; overlapping error boxes.
COMMENTS:       Burst_Validity flag is true.

GCN notice #2178
D. A. Smith on behalf of the ROTSE collaboration reports:
The ROTSE-IIIa telescope at Siding Spring Observatory, NSW, responded automatically to the HETE ground alert 2695, beginning its first image less than seven seconds after the alert time stamp, or 1.87 hours after the burst trigger. The automated burst response sequence consisted of ten 5-s, ten 20-s, and forty 60-s images. No sources not already in the USNO catalog were found within 1.5 error radii of the SXC burst location. Typical limiting magnitudes for these images were 17.3, 18.2, and 18.7, respectively. These magnitudes are unfiltered and calibrated against the USNO A2.0 catalog R-band. We co-added the first five sets of ten frames to push the limiting magnitudes to 18.8, 19.5, and 19.9, respectively. No candidate counterpart sources were found near the error box.
GCN notice #2184
A. Gilmore and P. Kilmartin (U. Canterbury) and A. Henden (USRA/USNO) report:
We have imaged part of the error circle for the HETE burst GRB030429 (HETE trigger 2695) with the Mt. John 0.6m telescope (unfiltered, using Rc zeropoint) and the USNOFS 1.55m telescope (Rc filter). We find one fading object that may be the optical counterpart to GRB030429. This object does not appear on the DSS-2 red plate. Its position, along with one comparison star from USNO-A2.0, is
```
OT     12:13:07.50  -20:54:49.7  J2000  (err: +/- 0.3arcsec)
Star A 12:13:01.05  -20:56:06.6  Rc=12.6
```
where coordinates are based on USNO-A2.0. A 4x4arcmin R-band finding chart can be found at ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb030429r.jpg The candidate is about 7arcsec southwest of a 19th magnitude star. Photometry of the candidate with respect to Star A, starting about 3.5hrs after the burst, yields:
```
   UTmid    CRmag   CRerr
Apr 29.591  19.34  0.11
Apr 29.600  19.43  0.13
Apr 29.616  19.71  0.16
Apr 29.660  19.87  0.19
```
It has faded more than another magnitude by May 01.25. The color of the candidate is blue, but accurate colors will be posted after calibration reductions are complete.
These observations were made as part of the AAVSO GRB Network, and supported by a grant from the Curry Foundation.
GCN notice #2185
Johan P. U. Fynbo (U. of Aarhus), Jens Hjorth (U. of Copenhagen), Sylvio Klose (TLS Tautenburg), Javier Gorosabel (IAA-CSIC/STScI), Andrew Levan (U. of Leicester), Nial Tanvir (U. of Hertfordshire), report on behalf of the GRACE collaboration:
"We have observed the field of GRB 030429 (=HETE trigger 2695) on two epochs with the ESO VLT. Using ISAAC on UT1 we have obtained Js and Ks observations and with FORS2 on UT2 we have obtained V, R and I observations. Our observations were carried out on April 29.94 and April 30.20 UT, i.e. 12.6 and 18.1 hours after the burst. We confirm the fading of the afterglow candidate proposed by Gilmore et al. (GCN 2184). Between our two epochs the source has faded by 0.43 magnitudes in the V band. In our second epoch image the magnitudes of the source are about R=22 and Ks=17.9 implying a decay slope close to 1. The source is located 1.2 arcsec from an extended source NW of the afterglow position. This source has magnitudes of about R=24 and Ks=18.2. Our absolute photometry is based on preliminary zeropoints and is hence subject to considerable uncertainties.
We note that the source is located 1.2 arcmin from the center of and is hence formally outside the 90% SXC error-circle.
We acknowledge excellent support from the Paranal staff, in particular Cedric Ledoux, Rachel Johnson, Poshak Gandhi and Elena Mason."
GCN notice #2190
V.Rumyantsev (CrAO), A.Pozanenko (IKI) report:
We have imaged the error box of the HETE GRB030429 (HETE trigger 2695) with AT-64 telescope of CrAO. Several unfiltered images with exposures of 120 s were obtained in Apr. 29 between (UT) 18:19 and 20:57. The OT found by A.Gilmore at al. (GCN 2184) is marginally visible in co-added image. The midtime of the co-added image (39x120 s) is Apr. 29.820. Due to short focal length of AT-64 (F=900mm, F/1.4) the OT appears to be in the wing of the star
```
USNO A2.0  675-11945727
RA =12 13 07.92
DEC=-20 54 45.3
R=17.90  B=20.50
```
Star 1 in the image at http://grb.rssi.ru/GRB030429/030429_030429_at64.gif
The limiting magnitude of the image calibrated with USNO A2.0 catalog R-band is 20.7, so we can estimate the OT magnitude as brighter as R=20.7m. Our estimation is consistent with OT decay slope 2 which implies the observation by A.Gilmore at al. (GCN 2184).
Detailed calibration and PSF analysis is in a progress.
GCN notice #2195
S. Nishiyama, D. Baba, T. Nagata (Nagoya U.), N. Matsunaga (U. of Tokyo), and IRSF/SIRIUS team (Nagoya U., NAOJ), N. Kawai (Tokyo Tech), N. Tanvir (U. of Hertfordshire) report:
We observed the SXC error box of GRB 030429 (HETE alert 2695) with the Simultaneous three-color InfraRed Imager for Unbiased Survey (SIRIUS) on the Nagoya-SAAO 1.4m telescope (IRSF). For the afterglow candidate proposed by Gilmore et al. (GCN 2184), we get the J H Ks magnitudes at 4 epochs begining 6.6 hrs after the burst:
```
   UTmid     J     H     Ks
Apr 29.727  18.8  17.8  17.0
Apr 29.873  19.2  18.3  17.5
Apr 30.005  18.9  18.1  17.4
----------------------------
Apr 30.768  19.0  18.4  17.8
```
We estimate the uncertainty in the magnitudes is about 0.2 mag. The Ks magnitude seems to be consistent with that at April 30.20 reported by Fynbo et al. (GCN 2185). These observations confirm the fading behaviour, but they were made under non-photometric conditions, and the effect of the nearby NW source (GCN 2185) makes the photometry less reliable, suggesting the results should be treated with caution.
This message may be cited.
GCN notice #2196
Michael Weidinger, Johan P. U. Fynbo (U. of Aarhus), Jens Hjorth (U. of Copenhagen), Javier Gorosabel (IAA-CSIC/STScI), Paul Vreeswijk (ESO Chile), Sylvio Klose (TLS Tautenburg) report on behalf of the GRACE collaboration:
"We have observed the field of GRB 030429 (=HETE trigger 2695) around May 2.2 UT with the ESO VLT. Using FORS1 on UT1 we have obtained a spectrum of the optical afterglow (GCN 2184) covering 3800 - 8000 Angstrom. In the spectrum we identify a strong damped Ly-alpha line around 4442 Angstrom. This implies a lower limit of z=2.65 to the redshift of GRB 030429. The absence of Ly-alpha forest absorption on the red side of the line and the seemingly very large column density of the line renders a higher redshift very unlikely and we therefore conclude that z=2.65 is the redshift of GRB 030429.
We acknowledge excellent support from Cedric Ledoux, Rachel Johnson, Poshak Gandhi and Elena Mason at the Paranal Observatory."
GCN notice #2197
E. Berger (Caltech) and D. A. Frail (NRAO) report on behalf of a larger collaboration:
"We observed the error circle of GRB 030429 (HETE trigger 2695) with the VLA on 2003, May 2.10 UT at 8.46 GHz. No sources are detected within the error circle down to a 3-sigma limit of 0.18 mJy. In particular, we do not detect a radio source at the position of the optical counterpart detected by Gilmore et al. (GCN 2184)."
This message may be cited.
GCN notice #2208
I. Khamitov (TUG), I.Bikmaev (KSU), M.Parmaksizoglu (TUG); N. Sakhibullin, V. Suleymanov (KSU); R. Burenin, R. Sunyaev, D. Denissenko, M. Pavlinsky, O. Terekhov, A. Tkachenko, M.Gilfanov (IKI); Z. Aslan, O.Golbasi (TUG); U. Kiziloglu, A. Alpar, A. Baykal (METU);
report:
We have observed the GRB 030429 optical afterglow (HETE trigger 2695) with the 1.5-m Russian-Turkish Telescope RTT150 at TUG.
A set of 10 exposures by 5 min. duration each with Rc Bessell filter has been obtained on the night May 02/03, 2003, under good photometric conditions. Inspite of that TO was observered on large zenith distance, the seeing was stable and about 1.8 arcsec. We used TE Andor CCD with Marcony back-illuminated 2048 x 2048 chip (binned 2*2) cooled to -60C temperature. Aperture photometry was done according to Landolt stars observered at the same night. On combined (50 min) image there are two extended sources at the position of TO as noted in Fyndo at al. (GCN 2185). The brightness of the sources are close and Rc=23.5+/-0.5. Photometry was done without color term correction. The bright source on about 7 arcsec northeast of TO is not a star-like source. Combined image and part of finding chart from Gilmore at al. (GCN 2184) can be found at http://www.tug.tubitak.gov.tr/gozlemler/GRB030429.jpg

This message may be cited.
GCN notice #2211
J. Doty, R. Vanderspek, N. Butler, G. Crew, J. Villasenor, G. Monnelly, T. Cline, J. G. Jernigan, A. Levine, F. Martel, E. Morgan, G. Prigozhin, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams;
Y. Shirasaki, C. Graziani, T. Donaghy, M. Matsuoka, M. Suzuki, T. Tamagawa, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, T. Tavenner, Y. Nakagawa, D. Takahashi, R. Satoh, and Y. Urata, on behalf of the HETE WXM Team;
G. Ricker, J-L Atteia, N. Kawai, D. Lamb, and S. Woosley on behalf of the HETE Science Team;
M. Boer, J-F Olive, J-P Dezalay, C. Barraud and K. Hurley on behalf of the HETE FREGATE Team;
write:
At 10:42:22.68 UTC (38542.68 s UT) on 29 April 2003, the HETE FREGATE, WXM, and SXC instruments detected event H2695, a long GRB.
The burst triggered FREGATE in the 30-400 keV energy band. No real-time localization was sent to the GCN, since the weak fluence of the burst in the WXM energy band resulted in a location that did not meet the criteria for automatic propagation, and which was, in fact, incorrect.
Ground analysis of the WXM data produced a localization that was reported in a GCN Notice at 12:34:28 UT, 112 minutes after the burst. The WXM ground localization SNR was 6. The localization can be expressed as a 90% confidence rectangle, whose center is at:
WXM-Ground: R.A. = 12h 13m 18s, Dec. = -20d 51' 09" (J2000),
and whose corners lie at:
```
R.A. =  12h 13m 32s, Dec. = -21d 01' 55"
R.A. =  12h 12m 50s, Dec. = -20d 59' 56"
R.A. =  12h 13m 03s, Dec. = -20d 40' 26"
R.A. =  12h 13m 46s, Dec. = -20d 42' 22" (J2000).
```
Ground analysis of the SXC data produced a localization that was reported in the same GCN notice. The SXC ground localization SNR was 6. The localization can be expressed as a 90% confidence circle that is 2 arcminutes in radius and is centered at:
R.A. = 12h 13m 06s, Dec. = -20d 56' 00" (J2000).
(The GCN Notice incorrectly reported the radius as 1 arcminute due to operator error.)
The T_90 duration of the burst in the 30-400 keV band was > 14 s.
A light curve and skymap for GRB030429 is provided at the following URL:
http://space.mit.edu/HETE/Bursts/GRB030429
GCN notice #2213
I. Khamitov (TUG), I.Bikmaev (KSU), M.Parmaksizoglu (TUG); N. Sakhibullin, V. Suleymanov (KSU); R. Burenin, R. Sunyaev, D. Denissenko, M. Pavlinsky, O. Terekhov, A. Tkachenko, M.Gilfanov (IKI); Z. Aslan, O.Golbasi (TUG); U. Kiziloglu, A. Alpar, A. Baykal (METU);
The correct reference in GCN 2208 is Fynbo et al. (GCN 2185).
GCN notice #2214
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 about 3arcmin from the coordinates of the optical transient (Gilmore et al. GCN 2184) for the HETE burst GRB030429 (H2695; Doty et al. GCN 2211) with the USNOFS 1.0-m telescope on two marginal nights. 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/grb030429.dat The astrometry in this file is based on linear plate solutions with respect to UCAC2. The external errors are less than 100mas. Due to the high airmass and drifting smoke from prescribed forest fires, the external photometric error is larger for B and Ic than normal; approximately 0.05mag. We will acquire additional photometry in the next week or so to improve these errors. We will also reposition to center the optical transient.
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.
GCN notice #2215
Michael Weidinger, Johan P. U. Fynbo (U. of Aarhus), Jens Hjorth (U. of Copenhagen), Javier Gorosabel (IAA-CSIC/STScI), Sylvio Klose (TLS Tautenburg), Nial Tanvir (U. of Hertfordshire) report on behalf of the GRACE collaboration:
"Further analysis of the VLT spectra of the afterglow of GRB 030429 (GCN 2184) and the neighbor galaxy at a separation of 1.2 arcsec from the afterglow (GCN 2185, 2196) has led to the following conclusions. Based on absorption lines due to HI, OI, SiII, and CII we infer a redshift of z=2.6564+/-0.0008 for GRB 030429. Based on a single, weak emission line in the spectrum of the neighbor galaxy, which we interpret as [OII], and weak Calcium H and K absorption we infer a redshift of z=0.841+/-0.001 for the galaxy. This is consistent with the redshift of an absorption line in the spectrum of the afterglow if interpreted as MgII. This galaxy is therefore not the host galaxy of the GRB. In deep images obtained with the VLT/FORS2 on May 5 the afterglow is only barely detected. We do not find any evidence for a host galaxy at the position of the afterglow to R>25. The separation between the position of the afterglow and the z=0.841 neighbor galaxy of 1.2 arcsec is comparable to the Einstein radius for a massive galaxy at that redshift. Gravitational lensing could therefore affect the appearance of GRB 030429.
We acknowledge excellent support from the Paranal Observatory staff."
GCN notice #2218
V.Rumyantsev (CrAO), V.Biryukov (SAI, MSU), A.Pozanenko (IKI) report:
We have performed PSF analysis of combined image of the OT found by A. Gilmore (GCN 2184). The unfiltered image was obtained on Apr. 29 between (UT) 18:19 and 20:57 (GCN 2190). Based on field photometry (R-band) by A.Henden (GCN 2214) we estimate brightness of the OT:
```
Mid.Time     exposure  mag (Unfiltered)
  (UT)         sec

Apr.29.820   39x120    20.20 +/-0.15
```
This brightness estimation is consistent with OT decay slope ~ 1 reported by J.Fynbo (GCN 2185).
(We gratefully acknowledge the notion of J.Fynbo regarding the slope decay reported in our GCN 2190. Due to typo the slope decay was erroneously calculated as 2)

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Jochen Greiner, last update: 09-May-2003 [Disclaimer]