This file contains circulars for the 3 GRBs 060204 'A', 'B', and 'C' //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4654 SUBJECT: GRB 060204: a long GRB detected by INTEGRAL DATE: 06/02/04 14:58:54 GMT FROM: Sandro Mereghetti at IASF/CNR S. Mereghetti (IASF, Milano), D.Gotz (CEA, Saclay), N.Mowlavi, M.Chernyakova, M.Beck (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: A GRB lasting about 70 s has been detected by IBAS in IBIS/ISGRI data at 13:19:50 UT on February 4 2006. The refined coordinates (J2000) derived from the off-line analysis are: R.A. = 232.2335 [degrees] Dec. = -39.4438 [degrees] with an uncertainty of 2.5 arcmin. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4655 SUBJECT: GRB 060204B: Swift detection of a burst DATE: 06/02/04 15:26:50 GMT FROM: Scott Barthelmy at NASA/GSFC A. Falcone (PSU), L. Barbier (GSFC), S. Barthelmy (GSFC), D. Burrows (PSU), J. Cummings (GSFC/NRC), N. Gehrels (GSFC), S. Hunsberger (PSU), J. Kennea (PSU), H. Krimm (GSFC/USRA), F. Marshall (GSFC), D. Morris (PSU), D. Palmer (LANL), E. Rol (U Leicester), T. Sakamoto (GSFC) on behalf of the Swift team: At 14:34:24 UT, Swift-BAT triggered and located GRB 060204B (trigger=180241). The spacecraft slewed immediately. The BAT on-board calculated location is RA,Dec 211.795d,+27.683d {14h 07m 11s,+27d 40' 60"} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). There is missing data in the BAT TDRSS lightcurve message, so we can not say anything about the lightcurve at this initial quicklook. However, it appears to be a long burst. We will have to wait for the full Malindi data download. The spacecraft slewed promptly and the XRT began observing the GRB at 14:35:59 UT, 94.5 sec after the BAT trigger. A bright, uncatalogued, flaring source was found by the on-board centroiding algorithm at RA(J2000)=+14h 07m 14.6s DEC(J2000)=+27d 40' 34" with an uncertainty of 6 arcseconds radius (90% containment). This position lies 57 arcseconds from the center of the BAT error circle. UVOT took a finding chart exposure of 200 seconds with the V filter starting 101 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 18th mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the expected extinction of about 0.1 magnitudes. We note there is a cluster of galaxies at z=0.156 in this field. Even though the initial Notices went out with the Star Tracker Loss-of-Lock flag set, ground analysis has shown that the s/c was tracking accurately and that the position is good. We are currently in the Malindi telemetry downlink gap. We will not have further data for another 8 hours. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4657 SUBJECT: GRB060204B - SDSS pre-burst observations DATE: 06/02/04 16:47:26 GMT FROM: Richard J. Cool at U.of AZ/Steward Obs Richard J. Cool (Arizona), Daniel J. Eisenstein (Arizona), David W. Hogg (NYU), Michael R. Blanton (NYU), David J. Schlegel (LBNL), J. Brinkmann (APO), Donald P. Schneider (PSU), and Daniel E. Vanden Berk (PSU) report: The Sloan Digital Sky Survey (SDSS) imaged the field of burst GRB060204B prior to the burst. As these data should be useful as a pre-burst comparison and for calibrating photometry, we are supplying the images and photometry measurements for this GRB field to the community. Data from the SDSS, including 5 FITS images, 3 JPGS, and 3 files of photometry and astrometry, are being placed at http://mizar.as.arizona.edu/~grb/public/GRB060204B We supply FITS images in each of the 5 SDSS bands of a 8'x8' region centered on the GRB position (ra=211.795 (14:07:10.8), dec=27.6830 (27:40:58.8); Swift-BAT TRIGGER 180241), as well as 3 gri color-composite JPGs (with different stretches). The units in the FITS images are nanomaggies per pixel. A pixel is 0.396 arcsec on a side. A nanomaggie is a flux-density unit equal to 10^-9 of a magnitude 0 source or, to the extent that SDSS is an AB system, 3.631e-6 Jy. The FITS images have WCS astrometric information. In the file GRB060204B_sdss.calstar.dat, we report photometry and astrometry of 297 bright stars (r<20.5) within 15' of the burst location. The magnitudes presented in this file are asinh magnitudes as are standard in the SDSS (Lupton 1999, AJ, 118, 1406). Beware that some of these stars are not well-detected in the u-band; use the errors and object flags to monitor data quality. In the files GRB060204B_sdss.objects_flux.dat and GRB060204B_sdss.objects_magnitudes.dat, we report photometry of 629 objects detected within 6' of the GRB position. We have removed saturated objects and objects with model magnitudes fainter than 23.0 in the r-band. The fluxes listed in GRB060204B_sdss.objects_flux.dat are in nanomaggies while the magnitudes listed in GRB060204B_sdss.objects_magnitudes.dat are asinh magnitudes. All quantities reported are standard SDSS photometry, meaning that they are very close to AB zeropoints and magnitudes are quoted in asinh magnitudes. Photometric zeropoints are known to about 2% rms. None of the photometry is corrected for dust extinction. The Schlegel, Finkbeiner, and Davis (1998) predictions for this region are A_U=0.101 mag, A_g=0.074 mag, A_r = 0.054 mag, A_i=0.041 mag, and A_z=0.029 mag. There are currently no objects within 6 arcminutes of the GRB position in the SDSS spectroscopic database. SDSS astrometry is generally better than 0.1 arcsecond per coordinate. Users requiring high precision astrometry should take note that the SDSS astrometric system can differ from other systems such as those used in other notices; we have not checked the offsets in this region. More detailed information pertaining to our SDSS GRB releases can be found in our initial data release paper (Cool et al. 2006, astro-ph/0601218). See the SDSS DR4 documentation for more details: http://www.sdss.org/dr4. These data have been reduced using a slightly different pipeline than that used for SDSS public data releases. We cannot guarantee that the values here will exactly match those in the data release in which these data are included. In particular, we expect the photometric calibrations to differ by of order 0.01 mag. This note may be cited, but please also cite the SDSS data release paper, Adelman-McCarthy et al. (2006, ApJS, in press, astro-ph/0507711), when using the data or referring to the technical documentation. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4658 SUBJECT: GRB060204B, optical observation DATE: 06/02/04 16:51:42 GMT FROM: Eri Sonoda at U of Miyazaki/Japan E.Sonoda,S.Maeno,Y.Nakamura,S.Masuda,M.Yamauchi (University of Miyazaki) We have observed the field covering the error circle of GRB060204B (GCN 4655) with the unfiltered CCD camera on the 30-cm telescope at University of Miyazaki. The observation was started 14:44:39 UT, 10.25 min after the Swift trigger time. We have compared our data of 30 sec exposures with the USNO-A2.0 catalog, the upper limits are as follows: -------------------------------------------------------------- Start(UT) End(UT) Num. of frames Limit (mag.) -------------------------------------------------------------- 14:44:39 14:45:09 1 ~15.1 14:44:39 14:48:48 6 ~16.34 --------------------------------------------------------------- //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4659 SUBJECT: GRB 060204A: further INTEGRAL results DATE: 06/02/04 17:12:05 GMT FROM: Sandro Mereghetti at IASF/CNR S. Mereghetti (IASF, Milano), D.Gotz (CEA, Saclay) on behalf of the IBAS Localization Team report: The peak flux of GRB 060204A (GCN 4654) integrated over 1 s is 0.1 ph (9x10e-9 erg)/cmq/s in the 20-200 keV range. Its fluence in the same energy band is 4x10e-7 erg/cmq. A plot of the light curve will be posted at http://ibas.mi.iasf.cnr.it/IBAS_Results.html This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4660 SUBJECT: GRB 060204B: ART optical limit DATE: 06/02/04 17:14:52 GMT FROM: Ken ichi Torii at RIKEN K. Torii (Osaka U.) reports on behalf of the ART collaboration: The error region of GRB 060204B (Falcone et al. GCN 4655) was imaged with the 0.35m ART 3b telescope in Toyonaka, Osaka. From a stacked frame (60s x 20 in Ic), the following 3 sigma limit is derived for an optical counterpart of the XRT source (GCN 4655), with reference to USNO-B1.0 I magnitude. ----------------------------- StartUT Limits ============================= 14:59:31 >18.0I ============================= //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4661 SUBJECT: GRB060204B: Faulkes OT candidate DATE: 06/02/04 17:29:02 GMT FROM: Cristiano Guidorzi at ARI,Liverpool JMU C. Guidorzi, C.G. Mundell, R.J. Smith, A. Monfardini, A. Gomboc,I. A. Steele, C.J. Mottram, M.F. Bode (Liverpool JMU), E. Rol, P. O'Brien, N. Bannister (Leicester) report: "The 2-m Faulkes Telescope North followed up GRB060204B (SWIFT trigger 180241) 46.2 min after the GRB trigger time. We detect a new source in R and i' filters not present in the SDSS pre-burst images (Cool et al., GCN 4657) at the following position: 14:07:14.9 27:40:36.4 (J2000) with a magnitude R = 20.4 +- 0.4 mag (vs USNOB1), from 46.2 min to 57.0 min after the burst, and i'=20.1 +- 0.3 (vs SDSS i' band image), from 53.2 min to 58.8 min after the burst trigger time. The source lies inside the XRT error circle (Falcone et al. GCN 4655)." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4663 SUBJECT: GRB 060204C: Swift-BAT detection of a burst DATE: 06/02/04 21:30:36 GMT FROM: Scott Barthelmy at NASA/GSFC D. Grupe (PSU), S. Barthelmy (GSFC), D. Burrows (PSU), A. Cucchiara (PSU), J. Cummings (GSFC/NRC), N. Gehrels (GSFC), S. Hunsberger (PSU), J. Kennea (PSU), C. Markwardt (GSFC/UMD), F. Marshall (GSFC), D. Morris (PSU), D. Palmer (LANL), T. Sakamoto (GSFC) on behalf of the Swift team: At 20:33:43 UT, Swift-BAT triggered and located GRB 060204C (trigger=180274). The spacecraft slewed immediately. The BAT on-board calculated location is RA,Dec 92.727d,+70.171d {06h 10m 54s,+70d 10' 14"} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). This is a 64-sec image trigger, and as such, there is little that can be determined from the TDRSS lightcurve. The S/C slewed immediately and the XRT began taking data at 20:36:19 UT, 157 sec after the BAT trigger. The XRT on-board centroid algorithm did not converge and no prompt position is available, however, the XRT lightcurve suggests the possibility of a decaying source in the field of view. We are waiting for down-linked data to determine the presence of the source. UVOT took a finding chart exposure of nominal 200 seconds with the V filter starting 156 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. Image catalog data are not available at this time. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the expected extinction of about 0.6 magnitudes. No afterglow candiate was found in a second B finding chart taken at T+363 sec. Given that the star tracker had been out-of-lock for only 2 minutes prior to this trigger, it is very unlikely there is a problem with the attitude of this position solution, so we believe this location to be valid. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4664 SUBJECT: GRB 060204C: ROTSE-III Optical Limits DATE: 06/02/04 21:55:29 GMT FROM: Eli Rykoff at U of Michigan/ROTSE E.S. Rykoff (U Mich), S.A. Yost (U Mich), B. E. Schaefer (Louisiana State), F. Yuan (U Mich), T. Guver (U Istanbul), report on behalf of the ROTSE collaboration: ROTSE-IIId, located at the Turkish National Observatory at Bakirlitepe, Turkey, responded to GRB 060204C (Swift trigger 180274, GCN 4663), producing images beginning 6.8 s after the GCN notice time. An automated response took the first image at 20:35:04.8 UT, 81.8 s after the burst, under windy conditions. We took 10 5-sec, 10 20-sec and 31 60-sec eposures. These unfiltered images are calibrated relative to USNO A2.0 (R). Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma BAT error circle, for both single images and coadding into sets of 10. Individual images have limiting magnitudes ranging from 16.1-17.7; we set the following specific limits. start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd? -------------------------------------------------------------------- 20:35:04.8 20:35:09.8 5 16.1 81.8 N 20:35:04.8 20:37:11.5 126 17.7 81.8 Y 20:37:20.2 20:41:56.3 276 18.2 217.2 Y //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4665 SUBJECT: GRB 060204C: Liverpool Telescopes optical limit DATE: 06/02/04 23:32:29 GMT FROM: Andrea Melandri at Liverpool John Moores U A. Melandri, C.G. Mundell, A. Monfardini, A. Gomboc, C. Guidorzi, R.J. Smith, I.A. Steele, C.J. Mottram, D. Bersier, S. Kobayashi, M. Burgdorf, D. Carter and M.F. Bode (Liverpool JMU) report: "On Feb 04.86 UT the Liverpool Telescope robotically followed up the field of GRB060204C (Swift trigger 180274, Grupe et al, GCN 4663), beginning at 6.42 minutes after the burst event. The automatic "detection mode" procedure did not detect any obvious afterglow candidate brighter than about R=18.7 mag from 3x10-s images, confirmed by visual inspection. We note the presence of two bright stars in the field of view that limits our detection capabilities in the surrounding halos. This message can be cited" //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4666 SUBJECT: GRB 060204C: BOOTES-IR optical limits DATE: 06/02/05 00:30:01 GMT FROM: Martin Jelinek at Inst.Astrophys.Andalucia,Granada S. Guziy, S. Vitek, M. Jelinek, A.J. Castro-Tirado, A. de Ugarte Postigo, S.B. Pandey, J. Gorosabel, R. Cuniffe and S.C. Castillo (IAA Granada, Spain), P. Kubanek (ASU Ondrejov, Czech Rep. and ISDC Versoix, Switzerland), M.D. Sabau-Graziati (INTA Madrid, Spain) and R. Hudec (ASU Ondrejov, Czech Rep.), on behalf of larger colaboration report The 60cm robotic telescope BOOTES-IR located at Observatorio Sierra Nevada, Southern Spain, observed automatically the position of GRB060204C (Grupe et al. GCN 4663). The telescope slewed automatically within 3m5s after recieving the GCN alert and immediately started the observation. We do not see any optical transient in the GRB errorbox down to the foillowing 3-sigma limits: mean time after GRB exposure limit filter =================================================== 7m20s 70s 17.8 Rj 19m5s 270s 18.9 Rj =================================================== Note that BOOTES-IR is still in comissioning phase operating without the IR camera. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4667 SUBJECT: GRB 060204b: Keck/LRIS Afterglow Confirmation DATE: 06/02/05 00:32:49 GMT FROM: S. Bradley Cenko at Caltech D-S. Moon and S. B. Cenko (Caltech) report on behalf of a larger collaboration: We have imaged the field of GRB060204b (Falcone et al., GCN 4655) with the Low-Resolution Imaging Spectrometer mounted on the 10-m Keck I telescope. Observations consisted of 12 x 180 s images taken simultaneously in V and I, beginning approximately 18 minutes after the burst. We clearly detect the afterglow candidate proposed by Guidorzi et. al (GCN 4661). Furthermore, the object fades by approximately 1.4 magnitudes during our I-band observations, and we therefore confirm that this object is the afterglow of GRB060204b. In our first I-band image, the afterlow had a magnitude of 19.4 +/- 0.3 (calculated with respect to the USNO-B1 catalog). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4668 SUBJECT: GRB 060204C: OSN limits DATE: 06/02/05 00:38:48 GMT FROM: Martin Jelinek at Inst.Astrophys.Andalucia,Granada Martin Jelinek, D. Martinez, S. Guziy, S. Vitek and A. de Ugarte Postigo (IAA Granada, Spain) report: We imaged the error box of Swift GRB060204C (Grupe et al. GCN 4663) with the 1.5m telescope at Observatorio Sierra Nevada. We do not detect any new or variable source within the BAT error box down to the limiting magnitude I=21.0 at an image obtained 38minutes after the GRB. The image is calibrated against USNO-B1.0 I2 magnitude. Further observations are in progress. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4669 SUBJECT: GRB060204B: Swift XRT Team Refined Analysis DATE: 06/02/05 03:44:58 GMT FROM: Abe Falcone at PSU/Swift A. D. Falcone (PSU), D. N. Burrows (PSU), D. C. Morris (PSU), N. Gehrels (GSFC) report on behalf of the Swift XRT team: We have analyzed the initial Swift XRT data from GRB 060204B (Falcone et al., GCN4655), with a total exposure of 178 s in Windowed Timing mode and 7790 s in Photon Counting mode. The refined XRT position is: RA(J2000) = 14 07 14.8 Dec(J2000) = +27 40 34 This position is 3" from the initial XRT on-board centroiding position reported in GCN 4655, and it is 2.8" from the optical detection reported by Guidorzi et. al (GCN 4661). We estimate an uncertainty of 4 arcseconds radius (90% containment). The early light curve is dominated by flaring with rates reaching approximately 200 c/s. Following the initial flaring, the light curve is clearly fading, but the rate is difficult to estimate due to the flaring and the limited data available at this time. A preliminary estimate of the power law decay index is approximately 0.6 +/- 0.4, immediately following the flaring activity. There is some indication that the lightcurve may become steeper beyond approximately 10 ks. Based on a preliminary spectral fit to the PC data in the time region between 200-5000 seconds, the spectrum can be described by an absorbed power law, with a power law photon index of 1.9 +/- 0.2 and N_H of 10e20 +/- 5e20 cm^-2. The 0.2-10 keV flux during this time frame is estimated to be approximately 4e-12 erg/cm^2/s. This Circular is an official product of the Swift XRT Team. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4670 SUBJECT: GRB 060204B: ART early limit DATE: 06/02/05 04:09:16 GMT FROM: Ken ichi Torii at RIKEN K. Torii (Osaka U.) reports on behalf of the ART collaboration: In addition to that reported in GCN 4660, we made further analysis of the early ART 3b data for GRB 060204B (Falcone et al. GCN 4655). The position of the optical afterglow (Guidorzi et al. GCN 4661; Moon & Cenko GCN 4667) was imaged very close to the edge of the ART 3b field of view, starting at 14:36:45 (141 s after the BAT trigger). From the preliminary analysis of a stacked frame (60s x 10 in Ic), we derive the following limit for the afterglow. ----------------------------- StartUT Mag ============================= 14:36:45 >16.0I ============================= //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4671 SUBJECT: GRB 060204B: Swift-BAT refined analysis DATE: 06/02/05 04:41:50 GMT FROM: Takanori Sakamoto at NASA/GSFC C. Markwardt (GSFC/UMD), L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/ORAU), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), F. Marshall (GSFC), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (ISAS), T. Takahashi (ISAS), J. Tueller (GSFC), on behalf of the Swift-BAT team: Using the data set from T-299.1 to T+303.0 sec from the recent telemetry downlink, we report further analysis of BAT GRB 060204B (trigger #180241) (Falcone, et al., GCN 4655). The BAT ground-calculated position is (RA,Dec) = 211.812, 27.675 deg {14h 7m 14.9s, 27d 40' 29.1"} (J2000) +- 0.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 77%. The mask-weighted light curve shows a strong peak with a slow rise starting from T-30 sec to T+5 sec, and a faster decay till T+30 sec. The weak emission extends to T+120 sec, and there is a small peak at T+120 sec. There is a possible precursor at T-165 sec with a width of ~20 sec. T90 (15-350 keV) is (134 +- 5) sec (estimated error including systematics). The time-averaged spectrum from T-24.4 to T+170.7 is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.82 +- 0.40, and Epeak of 96.8 +- 41.0 keV (chi squared 38.83 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is (3.0 +- 0.2) x 10^-06 erg/cm2 and the 1-sec peak flux measured from T+5.04 sec in the 15-150 keV band is (1.3 +- 0.2) ph/cm2/sec. A fit to a simple power law gives a photon index of 1.46 +- 0.09 (chi squared 47.69 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4672 SUBJECT: Swift XRT Observation of GRB 060204C DATE: 06/02/05 05:02:35 GMT FROM: Dirk Grupe at PSU/Swift-XRT D. Grupe, J. A. Kennea, and D. N. Burrows (PSU) report on behalf of the Swift XRT team: The Swift XRT began observing the field of BAT trigger 180274 (presumed to be GRB 060204C) at 20:36:20 (157 seconds after the BAT trigger). In the first 4 orbits of data (total exposure 8.0 ks) we find no evidence for any source within the BAT error circle. We place an upper limit of 1e-14 ergs/s/cm2 on any X-ray counterpart to this event. We do find a fairly bright source 8 arcminutes from the BAT position at (RA, Dec, J2000) = (06:12:23.0, +70 12 42.9), but this object is not fading and appears to be coincident with an object in the DSS (but not in the ROSAT All-sky survey). We note that it is extremely unusual for the XRT to slew promptly to a long GRB and not find a bright X-ray source in the field of view. In fact, there have been no previous cases in which the XRT slewed to a long GRB field in less than 300 seconds and did not detect an afterglow. This Circular is an official product of the Swift XRT Team. [GCN OPS NOTE(05feb06): Per author's request, the Subject-line was changed from "060402C" to "060204C".] //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4673 SUBJECT: GRB 060204C: optical observations DATE: 06/02/05 05:10:38 GMT FROM: Daniele Malesani at SISSA-ISAS,Trieste,Italy S. Piranomonte (INAF/OARm), D. Malesani (SISSA), H. Navasardyan (INAF/OAPd), N. Masetti (INAF/IASF Bo), report on behalf of a larger collaboration: We observed the field of GRB 060204C (Grupe et al., GCN 4663) with the Asiago telescope equipped with the AFOSC camera. Ten exposures lasting 3 minutes each were acquired, starting on 2006 Feb 4.9009 UT (mean time Feb 4.9172 UT, i.e. 1.45 hr after the GRB). The seeing was quite bad (~2.4 arcsec). Visual inspection of the coadded frame reveals no new objects inside the whole BAT error circle, after comparison with the DSS-II. The limiting magnitude of our images is estimated to be R ~ 21.8 (calibrated against the USNO-B1 catalog). Our images do not cover the position of the XRT source mentioned in GCN 4672 (Grupe et al., GCN 4672), which lies outside the BAT error circle. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4674 SUBJECT: GRB060204B: Swift/UVOT refined analysis DATE: 06/02/05 06:56:16 GMT FROM: Antonino Cucchiara at PSU A.Cucchiara, A Falcone, S. Hunsberger (PSU),F. Marshall (GSFC), P. Boyd (GSFC-UMBC), N. Gehrels (GSFC), on behalf of the Swift UVOT team. The Swift/UVOT began taking data on the field of GRB 060204B at 14:34:24 UT on 2006-02-04, 101 s after the BAT trigger (Falcone et al., GCN 4655). We detected an uncatalogued object cosistent with the xrt position reported by Falcone et al. (GCN 4669) and Guidorzi et al. (GCN 4661) in our first 200 exposure V image. We have no afterglow detection in summed images in any other filter within the refined XRT error circle down to the following 3-sigma magnitude upper limits. Filter T_range(s) Exp(s) mag coadd V 101-301 200 19.43+/- 0.50 N B 307-703 396 >20.12 Y U 4086-4890 91 >19.66 Y UVW1 4062-4746 98 >18.90 Y UVM2 4020-4722 95 >18.98 Y UVW2 427-4237 97 >19.11 Y These magnitudes are uncorrected for Galactic extinction; E(B-V) = 0.018. This message can be cited //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4675 SUBJECT: GRB 060204A: FRAM optical observations DATE: 06/02/05 11:54:49 GMT FROM: Petr Kubanek at AIO Petr Kubanek (ASU Ondrejov, Czech Rep. and ISDC Versoix, Switzerland), Michael Prouza (FZU Praha, Czech Rep.), Martin Jelinek (IAA Granada, Spain), Martin Nekola and Rene Hudec (ASU Ondrejov, Czech Rep.) Report: The wide field camera of the FRAM telescope, located at Pierre Auger Observatory in Malargue, Argentina, observed the field of INTEGRAL GRB 060204A (S. Mereghetti et al., GCN 4654, 4659) starting at 2006-02-05 02:40 UT, eg. 13 h 21 m post GRB. Comparison of combined 47x60 sec exposures (2820 sec total exposure) with USNO does not reveal any new source within INTEGRAL error box down to R mag ~ 14.5. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4676 SUBJECT: GRB 060204A: Swift XRT upper limit DATE: 06/02/05 15:23:49 GMT FROM: Albert Kong at MIT A. Kong (MIT) We report a follow-up Swift XRT observation of the INTEGRAL detected burst GRB 060204A (Mereghetti et al. GCN 4654). The XRT observation began at 2006 Feb 5 00:08:01 UT, 11 hrs after the burst. The XRT observation lasted for 5.2 ksec and we found no source within the 2.5 arcmin INTEGRAL error circle. We place a 3 sigma upper limit on the flux of the afterglow of 4.1e-14 erg cm^-2 s^-1 (0.2-10 keV) assuming a power-law with a photon index of 2 and a Galactic absorption of 1e21 cm^-2. The only X-ray source in the XRT field is 1RXS J152756.5-393155. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4677 SUBJECT: GRB 060204B: BVRi-band detections of optical afterglow DATE: 06/02/05 18:12:58 GMT FROM: Javier Gorosabel at IAA-CSIC J.P.U. Fynbo, J. Gorosabel(*), B.L. Jensen (DARK Cosmology Centre), Jyri Naeraenen (Helsinki Observatory) report on behalf of a larger collaboration: "We have acquired BVRi-band images (3x300s in each band) of the Swift GRB 060204B (Trigger number 180241, GCNs #4655, #4669) optical afterglow (GCN #4661). The source is clearly detected in VRi, and barely in B. We derive a rough magnitude of R=22.5 on Feb 5.07 UT (vs. USNOB1). Considering the R=20.4 mag value on Feb. 4.64 UT (as reported in GCN #4661) we estimate a slow-fading decay index alpha ~-0.8. Our B-band detection imposes a conservative maximum redshift of z ~< 4. A finding chart of the R-band afterglow can be found at: http://www.dsri.dk/~jgu/grb060204B/FCs/grb060204B.NOT.R.gif This message can be cited." (*) Visitor at DARK cosmology centre. Default affiliation; IAA-CSIC, Granada. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4678 SUBJECT: GRB060204C: optical observation DATE: 06/02/05 19:40:13 GMT FROM: Alexei Pozanenko at IKI, Moscow M. Andreev (Institute of Astronomy), A. Pozanenko (IKI) on behalf of larger GRB follow up collaboration report: We observed the field of GRB 060204C (Grupe et al., GCN 4663) in R-band with the 60 cm telescope of peak Terskol observatory starting Feb. 04 (UT) 20:56. Totally we obtained 27x60 s images in two epochs (UT) 20:56-21:10, and 21:22-21:35. Within whole BAT error circle in a combined image we found an object which is marginally visible in DSS2(R) and not presented in USNO-B1.0; coordinates of the object are (J2000) RA= 06h 10m 38.4s Dec= +70 09 32.4 with uncertainty in both coordinates of about 0.1". Brightness of the object is measured in the combined image is R=19.2 +/-0.1. The object is not variable between the two epochs within error bars. The astrometry and photometry calibration is based on USNO-B1.0. While the object is not variable between our epochs and marginally visible in DSS2(R) and detected better in DSS2(I), the object may be a host galaxy of GRB060204C if fading brightness of the object will be confirmed. The stacked image can be found in http://grb.rssi.ru/GRB060204c/grb060204C_Z600_R.jpg //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4679 SUBJECT: BAT GRB 060204C is probably not a GRB DATE: 06/02/05 23:09:37 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto (GSFC/ORAU), L. Barbier (GSFC), S. Barthelmy (GSFC), P. Boyd (GSFC-UMBC), J. Cummings (GSFC/ORAU), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), G. Sato (ISAS), J. Tueller (GSFC), W. Voges (MPE) on behalf of the Swift-BAT team: Using the data set from T-299.0 to T+303.1 sec from the recent telemetry downlink, we report further analysis of BAT trigger #180274 (Grupe, et al., GCN 4663). The BAT ground-calculated position is (RA,Dec) = 92.715, 70.174 deg {6h 10m 58.5s, 70d 10' 41.7"} (J2000) +- 3.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 39%. The mask-weighted light curve shows a single broad peak in the 15-50 keV band with no significant emission above 50 keV. T90 (15-350 keV) is (60 +- 5) sec (estimated error including systematics). The time-averaged spectrum from T+0 to T+64 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.4 +- 0.6. The fluence in the 15-150 keV band is (3.5 +- 1.2) x 10^-07 erg/cm2. The average photon flux measured from T+0 to T+64 sec in the 15-150 keV band is (0.10 +- 0.03) ph/cm2/sec. All the quoted errors are at the 90% confidence level. This source was detected at the 4.8-sigma level 1.5 days earlier at the same location. There is 0.1% probability that this pre-trigger detection is a chance coincidence. This plus the very soft nature of the spectrum forces us to conclude that this is probably not a real GRB, but is very likely a hard X-ray transient. Further analysis has shown that even though the star tracker had a loss-of-lock during the initial trigger, the tracking error was much smaller than our stated location uncertainty. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4681 SUBJECT: GRB 060204C: XRT analysis of Swift J061223.0+701243.9 DATE: 06/02/06 01:48:11 GMT FROM: Dirk Grupe at PSU/Swift-XRT authors: D. Grupe (PSU), D. Burrows (PSU)., D. Morris (PSU), T. Sakamoto (GSFC), N. Cucchiara (PSU), A. Retter (PSU), S. Barthelmy (GSFC) on behalf of the Swift team We report on the analysis of the X-ray source Swift J061223.0+701243.9 which is inside the Field of view of BAT trigger 180274 (GRB 060204C). As discussed by Grupe et al (GCN 4672) this source is about 8' away from the BAT position reported by Grupe et al. (GCN 4663). The XRT position of this source is: RA-2000: 06 12 22.97 Dec-2000: +70 12 43.9 with an error radius of 3.6" Note that even though there was a star tracker loss-of-lock during the initial trigger, we consider this position as very reliable. The total exposure time of the field is 22.6 ks which were acquired within 58.2 ks. The light curve initially shows a brightening followed by a decreasing count rate starting about 10 ks after the trigger. Below we list the light curve with time after the trigger (in seconds), count rate and count rate error (in units of XRT counts/s): Time cr cr_err ------------ ------- ---------- 2.61399e+02 1.82e-02 7.03e-03 5.25616e+03 5.94e-02 4.88e-03 1.10075e+04 6.39e-02 5.06e-03 1.68026e+04 3.43e-02 3.65e-03 2.18468e+04 5.66e-02 6.91e-03 2.75906e+04 5.16e-02 7.24e-03 3.43580e+04 2.06e-02 2.92e-03 4.03060e+04 4.35e-02 4.20e-03 4.61773e+04 3.19e-02 3.61e-03 5.20307e+04 2.07e-02 2.89e-03 5.63931e+04 2.23e-02 3.34e-03 The spectral analysis shows excess absorption above the Galactic value (9e20 cm-2) with 18.8+2.9-6.1 with a photon index Gamma = 1.52+0.16-0.15. Because we do not know the nature of this X-ray transient source (it was not present in the ROSAT All-Sky Survey) we encourage optical observers to derive a spectrum to identify the source. Due to the distance of 8' away from the BAT position we do not consider this X-ray source an afterglow of GRB 060204C. As discussed by Sakamoto et al (GCN 4679) BAT trigger 180274 is most likely not a real GRB and probably a hard X-ray transient. We have no further plan to re-observe the field of BAT trigger 180274. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4685 SUBJECT: GRB060204a: Swift XRT Detection of an Afterglow Candidate DATE: 06/02/06 07:38:45 GMT FROM: David Morris at PSU/Swift-XRT D. Morris (PSU), D. Burrows (PSU), N. Gehrels (GSFC), F. Marshall (GSFC), M. Chester (PSU) on behalf of the Swift XRT team: The Swift XRT began observing GRB 060204a, detected by INTEGRAL (Mereghetti et al., GCN 4654), at 00:08:02 UT on 05 February 2006 (39 ks after the burst trigger). In 14.5 ks of data, we find a faint, uncataloged X-ray source within the 2.5 arcminute INTEGRAL error circle at: RA(J2000): 15:28:58.4 DEC(J2000): -39:27:28.5 with an uncertainty of 5 arcsec (90% containment). This position includes the latest XRT boresight correction and is 58 arcseconds from the INTEGRAL reported position in GCN 4654. We calculate an average flux for this source of 1e-13 ergs/cm2/s (0.2-10keV unabsorbed) assuming a powerlaw index of 2 and galactic absorption of 1e21 cm^-2. We note that this source flux is brighter than the 3-sigma upper limit reported in GCN 4676 (Kong). Due to the small number of counts, we are unable to determine whether the source is fading at this time. We note, however, that the detected flux is consistent with typical GRB afterglow flux levels at T+100ks, which is the mean epoch of this observation. Observations are continuing and further analysis regarding the fading nature of this source will be issued as the data become available. This circular is an officical product of the Swift XRT Team. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4698 SUBJECT: GRB060204A: Swift/UVOT observations DATE: 06/02/06 22:26:26 GMT FROM: Antonino Cucchiara at PSU A. Cucchiara, D. Fox, S. Hunsberger, A. Retter, J. Nousek (PSU), W. Voges (MPE), N. Gehrels (GSFC), on behalf of the Swift UVOT team. The Swift/UVOT began observing the field of GRB 060204A, detected by INTEGRAL (Mereghetti et al., GCN 4654) at 00:17:07 UT on 2006-02-05, 10.8 hours after the trigger. Within the XRT error circle reported by Morris et al. (GCN 4685) we found a DSS/USNO catalogued object (USNO B1 0505-0367492, B magnitude = 15.48). This is only 2 arcsecond from the XRT position. A preliminary analysis of this known source shows a fading behaviour followed by a rebrightening on a timescale of a day. For comparison, our B magnitude at the beginning of the observation was 14.14 (+/- 0.03), corrected for galactic extinction (E(B-V)=0.182)). At the moment, we cannot infer whether this is the optical afterglow of this GRB or a kind of activity due to the catalogued object. More XRT observations are ongoing to see if the XRT source fades away. Further analyses are forthcoming. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4700 SUBJECT: GRB 060204A: ROSAT Pointing DATE: 06/02/07 00:34:46 GMT FROM: Jules Halpern at Columbia U. I note that a faint ROSAT PSPC source was detected in a pointed observation in 1992 at a position and flux consistent with the Swift XRT source (Morris et al., GCN 4685) in the INTEGRAL error circle of GRB 060204A (Mereghetti et al., GCN 4654, 4659). This is not the RASS source mentioned by Kong (GCN 4676). The source 2RXP J152858.6-392721 has 0.0112+/-0.0023 ct/s, and its 8" radius error circle is also very near the bright variable star detected in the Swift UVOT (Cucchiara et al., GCN 4698), suggesting that these objects are identical: R.A.(2000) Dec.(2000) +/-(") -------------------------------------------------- Swift XRT 15 28 58.4 -39 27 28.5 5 ROSAT PSPC 15 28 58.55 -39 27 20.9 8 USNO B1.0 15 28 58.79 -39 27 30.4 -------------------------------------------------- These results together argue that the Swift candidate is a variable Galactic source rather than a GRB afterglow. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4704 SUBJECT: GRB 060204b: pseudo-z from spectral parameters of the prompt emission DATE: 06/02/07 14:21:22 GMT FROM: Jean-Luc Atteia at Lab d Astrophys.,OMP,Toulouse A. Pelangeon & J-L. Atteia (LATT-OMP) report: We have used the spectral parameters for the most intense part of GRB 060204B (from T0-4.46 sec. to T0+10.54 sec.) kindly provided by T. Sakamoto (GSFC, private communication) to compute the spectral pseudo-redshift of this burst detected by SWIFT-BAT (Falcone et al., GCN 4655; Markwardt et al., GCN 4671). We find a pseudo-redshift pz= 3.1 ± 1.1 This is consistent with the observations of the afterglow by Fynbo et al. (GCN 4677) who imposes a conservative maximum redshift of z ~< 4. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4707 SUBJECT: GRB060204a: Swift XRT Source is not GRB Afterglow DATE: 06/02/07 18:22:26 GMT FROM: David Morris at PSU/Swift-XRT D. Morris (PSU), D. Burrows (PSU), N. Gehrels (GSFC) on behalf of the Swift XRT team: Further Swift XRT observations of the X-ray source detected within the INTEGRAL error circle (GCN 4685, Morris et al) have shown that the source is not fading. This information, together with the coincident, bright, non-fading source detected in the UVOT (GCN 4698, Cucchiara et al) and the archival ROSAT pointed observation detection of an X-ray source consistent with this source position (GCN 4700, Halpern), indicates that this source is not the afterglow of GRB060204a. Swift XRT has now collected 24ks of data on this field, producing an upper limit on the unabsorbed flux of the afterglow in the 0.2-10keV band of 2e-14 ergs/cm2/s at a mean epoch of T+120ks. This upper limit assumes an absorbed powerlaw spectrum with photon index of 2 and galactic absorption of 1e21cm-2. No further observations are planned. We note that Swift BAT and XRT have previously detected GRBs which have subsequently become undetectable to a similar limiting flux level in the XRT on timescales similar to our observation of this field, including GRB050421, GRB051117b and GRB051210. This circular is an official product of the Swift XRT Team. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4829 SUBJECT: GRB 060204B: GETS early limit DATE: 06/02/25 07:19:08 GMT FROM: Kenzo Kinugasa at Gunma Astro. Obs/Japan K. Kinugasa (Gunma Astronomical Observatory) and K. Torii (Osaka U.) report: The error region of GRB 060204B (Falcone et al. GCN 4655) was imaged by the robotic 0.25m GETS telescope in the Gunma Astronomical Observatory. Unfiltered imaging started at 14:36:23 UT (119 s after the BAT trigger) and 30 s integration was repeated. We did not detect the optical afterglow (Guidorzi et al. GCN 4661; Moon & Cenko GCN 4667) and the following 3-sigma upper limits are derived relative to USNO-A2.0 R mag. ------------------------------------------ StartUT EndUT Limit Nframes ------------------------------------------ 14:36:23 14:36:53 >16.9 1 14:36:23 14:50:00 >18.4 20 ------------------------------------------