//////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1837 SUBJECT: GRB 030131 optical observations DATE: 03/01/31 12:10:35 GMT FROM: Ryan Chornock at UC Berkeley R. Chornock, W. Li, A. V. Filippenko, and S. Jha (UC Berkeley) report: We imaged a 6.8' x 6.8' field centered at the position of GRB 030131 (GCN 1836) with the Katzman Automatic Imaging Telescope (KAIT) starting at 11:12:23 UT, 3.6 hours after the burst. Visual comparison of a single 300s unfiltered exposure to the Digitized Sky Survey shows no new object down to a limiting magnitude of about 19.5. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1838 SUBJECT: GRB030131: refined position DATE: 03/01/31 13:03:03 GMT FROM: Sandro Mereghetti at IASF/CNR D.Gotz, S.Mereghetti and J.Borkowski for the IBAS localization team report: The refined position of GRB030131 is RA 13h 27m 56s, DEC +30deg 46' 7'' with an uncertainty of 5 arcmin radius. These coordinates differ by 10.4 arcmin from the preliminary position reported in GCN 1836. This message can be cited //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1839 SUBJECT: GRB 030131 optical observations DATE: 03/01/31 13:19:07 GMT FROM: Tommy Grav at U.of Oslo T. Grav (University in Oslo & Harvard-Smithsonian Center for Astrophysics) report: A 10' x 10' field centered on the position of GRB 030131 (GCN 1836) was imaged with the 48" reflector at the Fred Whipple Lawrence Observatory starting at 11:26:12 UT, 3.8 hours after the burst. 600s exposures in both V and R was compared to the Digitized Sky Survey, and no new objects down to a limiting magnitude of about 20.5 was found. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1840 SUBJECT: GRB030131: Optical limit DATE: 03/01/31 14:53:46 GMT FROM: Derek Fox at CIT P.A. Price (RSAA/ANU) and D.W. Fox (Caltech) report on behalf of a larger collaboration: "We have imaged the full localization region of GRB030131 (GCN 1838) with the Palomar 48-inch Oschin Telescope + NEAT camera, in six 120s exposures over 10:42 UT to 11:31 UT. The summed image from these unfiltered exposures reaches a limiting magnitude of R~21 mag as estimated from the magnitude of several USNO-A2.0 stars in the image. We identify no new sources by reference to images from the Second Digitized Sky Survey. We estimate the magnitude of any new source to be R>20 mag at the mean epoch of our observations, 11:16 UT, which is 3.62 hours after the burst." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1841 SUBJECT: IPN triangulation of GRB030131 DATE: 03/01/31 22:07:31 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses GRB team, A. von Kienlin, G. Lichti, and A. Rau, on behalf of the INTEGRAL SPI-ACS GRB team, and S. Mereghetti, J. Borkowski, and D. Gotz, on behalf of the INTEGRAL IBIS GRB team, report: Ulysses observed this burst (GCN 1836, 1838). As observed by Ulysses, it had a duration of approximately 100 s, a 25-100 keV fluence of approximately 1.E-06 erg/cm2, and a peak flux over 0.25 s of approximately 6.E-07 erg/cm2 s. We have triangulated it to a preliminary annulus centered at RA, Decl. (2000)= 176.751,+40.439 degrees, with radius 22.616 +/- 0.032 degrees (3 sigma). This annulus intersects the error circle given in GCN 1838 at: RA DEC 202.037 30.699 202.079 30.757 201.944 30.693 202.046 30.832 reducing its area by a factor of about 5, to 16 sq. arcmin. This localization may be improved. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1843 SUBJECT: IPN triangulation of GRB030131 - CORRECTION DATE: 03/02/01 19:40:26 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses GRB team, A. von Kienlin, G. Lichti, and A. Rau, on behalf of the INTEGRAL SPI-ACS GRB team, and S. Mereghetti, J. Borkowski, and D. Gotz, on behalf of the INTEGRAL IBIS GRB team, report: Further analysis of this event indicates that the IPN annulus (GCN 1841) is consistent with the error circle given in GCN 1838, but cannot in fact be used to constrain it. The error box given in GCN 1841 should be disregarded. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1845 SUBJECT: GRB030131: Kiso Observations DATE: 03/02/02 10:05:32 GMT FROM: Yuji Urata at RIKEN M. Ishiguro (ISAS) T. Soyano, H. Mito and Y. Urata on behalf of the Kiso GRB team: " We have observed the entire INTEGRAL error circle of GRB030131 (Gotz et al., GCN1838) with Kiso observatory 1.05 m Schmidt telescope. We obtained two R-band data sets (300 sec x 3 frames), starting at 15:36 UT and 18:45 UT. Our data; Date Time (UT) Exposure Limiting mag.(R, SN=3) 01-31 15:36:47 300s x 3 19.7 01-31 18:45:00 300s x 3 20.0 # Limiting magnitude was estimated by comparison with # U1200_07092706 13:27:46.834 +30:44:13.42 16.4 mag. Comparison with DSS II red images, no new object was detected down to the limiting magnitude. We also could not identify any variable objects in the region reported by Hurley et al (GCN1841) using a PSF matched image subtraction method." This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1847 SUBJECT: GRB030131: corrected INTEGRAL position DATE: 03/02/03 11:51:32 GMT FROM: Sandro Mereghetti at IASF/CNR S.Mereghetti (IASF-Milano), N.Produit (ISDC), J.Borkowski (ISDC), D.Gotz (IASF-Milano) and the INTEGRAL Science Working Team report: Further analysis of GRB030131 resulted in a better localization which differs from the ones previously reported (GCN1836, 1838). Previous results were affected by the fact that the burst occurred during a satellite slew. The new coordinates are RA: 13h 28m 31s DEC: +30deg 40' 45'' with an error of 5 arcmin radius. The GRB had a duration of about 150 s and a peak flux over 1 s of about 2x10e-7 erg/cm2/s in the 25-100 keV energy range. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1849 SUBJECT: GRB 030131: afterglow candidate DATE: 03/02/03 19:41:56 GMT FROM: Arto Oksanen at Nyrola Obs., Finland A. Oksanen (Jyvaskylan Sirius ry) reports on behalf of Nyrola Observatory GRB-team and AAVSO International GRB Network: A 24' x 16 arcmin field covering the corrected INTEGRAL error circle of GRB 030131 (GCN 1848) was imaged with the 0.4m SCT at the Nyrola Observatory starting at February 1, 2003 03:49 UT, 20 hours after the burst. The 19 x 180s Rc-exposures were sigma reject combined and compared to the Digitized Sky Survey (DSS2R) and one faint (R=20.5) new object was found near the image limit. The position of the suspect is: 13:28:28.46 +30:42:05.4 J2000 using the USNO-A2.0 reference catalog. The combined image may contain some processing artifacts so the confidence that the suspect is a GRB OT is not very high. The FITS frame and a JPEG picture showing the corrected error circle plus the suspect OT are available on: http://nyrola.jklsirius.fi/grb/grb030131/ This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1850 SUBJECT: GRB030131: Optical limits for corrected position DATE: 03/02/03 22:17:27 GMT FROM: Derek Fox at CIT D.W. Fox (Caltech) and P.A. Price (RSAA/ANU) report on behalf of the Caltech-NRAO GRB collaboration: "We have imaged the full corrected localization region of GRB030131 (GCN 1847) with the Palomar 48-inch Oschin Telescope + NEAT camera, in six 120s exposures over 10:42 UT to 11:31 UT on 31 Jan 2003. The summed image from these unfiltered exposures reaches a limiting magnitude of R~21 mag as estimated from the magnitude of several USNO-A2.0 stars in the image. We identify no bright new sources by reference to images from the Second Digitized Sky Survey. We estimate the magnitude of any new source to be R>20 mag at the mean epoch of our observations, 11:16 UT, which is 3.62 hours after the burst. "In particular, the afterglow candidate of Oksanen (GCN 1849) is not present in our image, and we estimate R>21 for the quoted position at this epoch." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1851 SUBJECT: GRB030131: Kiso optical limit for corrected position DATE: 03/02/04 06:50:45 GMT FROM: Yuji Urata at RIKEN T. Soyano, H. Mito and Y. Urata on behalf of the Kiso GRB team, M. Ishiguro (ISAS) : "We have observed the entire corrected localization region of GRB030131(Mereghetti et al., GCN 1847) with Kiso observatory 1.05 m Schmidt telescope. We obtained two R-band data sets (300 sec x 3 frames), starting at 15:36 UT and 18:45 UT. Our limiting magnitude estimated from USNO-A2.0 stars is R~20. Comparison with DSS II red images, no new object was detected down to the limiting magnitude. We also could not identify the candidate of Okasanen (GCN 1849) at first and second epoch." This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1852 SUBJECT: GRB 030131, optical observations DATE: 03/02/04 12:36:34 GMT FROM: Sylvio Klose at TLS Tautenburg S. Klose and F. Ludwig, Thuringer Landessternwarte Tautenburg report: The field of GRB 030131 was imaged in the R band with the Tautenburg Schmidt telescope equipped with the prime focus CCD camera on Feb 4, 1:35 - 5:22 UT. The field of view is about 40 x 40 arcmin. Altogether 45 frames were taken (2 min exposure time each). The limiting magnitude of the combinded image is about R=22.5 +/- 0.5. The GRB field is very rich in galaxies. Exactly at the position of the potential afterglow candidate reported by Oksanen et al. (GCN 1849) we do not detect any source (R>~22.5). Several sources with R>~21 are visible within ~5 arcsec of the reported OT coordinates. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1857 SUBJECT: GRB030131: Candidate Optical Afterglow DATE: 03/02/05 07:13:26 GMT FROM: Derek Fox at CIT D.W. Fox (Caltech), P.A. Price (RSAA/ANU), T. Herter (Cornell), P. Appleton (IPAC), and G. Cotter (Cambridge) report on behalf of a larger collaboration: "We have observed the full corrected localization region (GCN 1847) for GRB030131 with the 60-inch telescope on Mt. Palomar (P60), for roughly 15 min each in Gunn r and i on the night of 4 Feb 2003 UT. We have also observed a portion of this region with the 200-inch Hale telescope + COSMIC (P200), for 30 min in R band on the night of 1 Feb 2003 UT (mean epoch 10:27 UT, or 26.8 hours post-burst). "Visual comparison of the P60 images with our summed 48-inch + NEAT (P48) image from 31 Jan 2003 UT (mean epoch 11:16 UT, or 3.62 hours post-burst; c.f. GCN 1850) reveals a point-like source in the P48 image that is not present in the P60 images. The unfiltered P48 magnitude of this source, R~21.2 by reference to four nearby USNO-A2.0 stars, is near the limit of the P60 r image. However, the source lies within the field of view of the P200 R-band image, and is barely detected with R>~23.5 at that time. "The coordinates of the source relative to the GSC-II are: RA 13:28:22.29, Dec +30:40:23.7 (J2000) with an uncertainty of less than 1" in each coordinate. Inspection of the individual P48 images reveals that the source is present at the same position in each image (mean epochs 10:43 to 11:32 UT, 31 Jan 2003). The brightness of the source in the various images is roughly constant, to within about one magnitude, although we observe possible variability of the source within this range. "We tentatively suggest that this source is the afterglow of GRB030131. We consider this identification provisional in the absence of further supporting observations." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1866 SUBJECT: GRB 030131: marginal optical detection DATE: 03/02/13 15:25:33 GMT FROM: Javier Gorosabel at LAEFF-INTA, Madrid J. Gorosabel (IAA-CSIC/STScI), A. Levan (U. Leicester/STScI), A. Fruchter, J. Rhoads, J.M. Castro Cerón (STScI), T. Tripp (Princeton) report for a larger collaboration: We have imaged the optical candidate (GCN 1857) of the INTEGRAL burst GRB 030131 (GCN 1836, GCN 1838, GCN 1847) with the 4-m KPNO telescope (equipped with Mosaic, FOV=36'x36'). The observations were carried out on Feb 1.526-1.542 UT 2003 (~29 hours after the GRB) with a total exposure time of 4x500s and a seeing of 0.85". We find a marginal detection (~3.5 sigma above the detection threshold) at RA(J2000)=13:28:22.27 DEC(J2000)=30:40:23.7. The astrometry is based on the USNO catalog and shows an internal uncertainty of 0.5" for each coordinate. We have compared the offset of the object in our image from the nearest USNO star with that found by D. Fox (personal communication) in their discovery image. These offsets agree within 0.2", further strengthening the association. Preliminary aperture photometry centered on the object yields B=25.4+/-0.3. Our photometric calibration is based on 11 USNO stars in the field. Under the zero point obtained the star located at RA(J200)=13:28:18.16 DEC(J2000)=30:38:20.79 has B=18.18. A smoothed image of the field can be seen at: http://www.stsci.edu/~fruchter/GRB/030131/kpno/grb030131.kpno.gif We thank D. Fox for providing valuable astrometric information. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1971 SUBJECT: GRB030131, BVRcIc field photometry DATE: 03/03/27 20:22:19 GMT FROM: Arne A. Henden at USNO/USRA A. Henden (USRA/USNO) reports on behalf of the USNO GRB team: We have acquired BVRcIc all-sky photometry for a 20x20 arcmin field centered at the candidate afterglow coordinates (Fox et al., GCN 1857) for the INTEGRAL burst GRB030131 (GCNs 1836, 1838, 1847) 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/grb030131.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 0.03mag. In particular, the star located at RA(J2000)=13:28:18.16 DEC(J2000)=30:38:20.79, used as a comparison star by Gorosabel et al. (GCN 1866) has B=18.95 +/- 0.03, making the OT fainter than what was given in that GCN. We will not be performing U-band calibration unless requested. As always, you should check the dates on the .dat file prior to final publication to get the latest photometry.