//////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3116 SUBJECT: GRB 050319: Detection of Possible Optical Counterpart DATE: 05/03/19 09:54:36 GMT FROM: Eli Rykoff at U of Michigan/ROTSE E. Rykoff (Umich), B. Schaefer (LSU), R. Quimby (UTexas) report on behalf of the ROTSE collagoration: ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 050319 (Swift 11162) in 9.2 s, 27 s after the burst. Our unfiltered images detect a 16th magnitude, fading source at: 10:16:47.9 +43:32:54.5 Continuing observations are in progress. The object is at ~18th magnitude, around 940 seconds after the burst. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3117 SUBJECT: Swift Detection of GRB 050319 DATE: 05/03/19 10:42:25 GMT FROM: Hans Krimm at NASA-GSFC Swift Detection of GRB 050319 H. Krimm (GSFC/USRA), M. Still (GSFC/USRA), S. Barthelmy, L. Barbier (GSFC), S. Campana (INAF-OAB), M. Capalbi (ASDC), M. Chester (PSU), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), M. R. Goad, O. Godet (U.Leicester), J. Greiner (MPE), D. Grupe (PSU), D. Hullinger (GSFC/UMD), V. La Parola , V. Mangano (INAF-IASF/Palermo), C. Markwardt (GSFC/UMD), P. Meszaros, D. C. Morris, J. A. Nousek (PSU), K. Page (U.Leicester), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), M. Suzuki (Saitama), G. Tagliaferri (INAF-OAB), J. Tueller (GSFC) report on behalf of the Swift-BAT and Swift-XRT teams: At 09:31:18.44 UT, the Swift Burst Alert Telescope (BAT) triggered and located on-board GRB 050319. The burst was 37 degrees off the BAT boresight. The spacecraft executed an immediate slew and was on target by 09:32:45.53 UT at which time the XRT began taking data in Auto State. On-board software recognized a bright source at location RA 154.2016d {+10h 16m 48s} (J2000), Dec +43.5463d {+43d 32' 47"} (J2000) We estimate an uncertainty of 7 arcseconds. The burst lightcurve as seen in the BAT has a single peak with a fast rise, exponential decay. The estimated duration is 15 seconds. The peak count rate is 2,000 counts/second (15-350 KeV). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3118 SUBJECT: GRB050319,optical observation DATE: 05/03/19 16:02:58 GMT FROM: Shouta Maeno at U.of Miyazaki S.Maeno,E.Sonoda,Y.Matsuo,M.Yamauchi (University of Miyazaki) "We have observed the field covering the error box of GRB 050319 (GCN 3117;Swift-BAT Trigger time is 09:31:18.44 UT) with the unfiltered CCD camera on the 30-cm telescope at University of Miyazaki. The observation was started 10:45:01 UT on Mar.19. Observed field of view is 43 arcmin centerd on R.A.=10h 17m 01s Dec.=+43d 31m 06s After co-adding a set of 9 images of 30 sec exposures, we have compared with the USNO-A2.0 catalog. Preliminary analysis shows there is no new source brighter than 17.8mag. at the reported position by GCN3116(E.Rykoff et al.) " //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3119 SUBJECT: GRB 050319: Swift-BAT refined analysis DATE: 05/03/19 16:18:59 GMT FROM: Hans Krimm at NASA-GSFC H. Krimm (GSFC/USRA), T. Sakamoto (GSFC/NRC), S. Barthelmy, L. Barbier (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (GSFC/UMD), C. Markwardt (GSFC/UMD), F. Marshall (GSFC), J. Nousek (PSU), D. Palmer (LANL), A. Parsons (GSFC), G. Sato (ISAS), M. Still (GSFC/USRA), M. Suzuki (Saitama), J. Tueller (GSFC) on behalf of the Swift-BAT team: Analysis of the full data set for the Swift-BAT GRB 050319 (Krimm, et al., GCN 3117) yields a fluence of 8 X 10^-7 erg/cm2 in the 15-350 keV band and a peak flux of 1.7 ph/cm2/sec (also 15-350 keV). The photon index of the 1-s peak spectrum ( starting at T0 +0.36 sec.) is 2.1 +- 0.3 (90% confidence). The time-averaged spectrum yields a photon index of 2.2 +- 0.2. The overall measures of burst duration give T90 = 10 +- 2 seconds (including systematics). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3120 SUBJECT: GRB 050319 : Confirmation of optical afterglow decay DATE: 05/03/19 16:42:37 GMT FROM: Yuji Urata at RIKEN GRB 050319 : Confirmation of optical afterglow decay T. Yoshioka (Naogya Univ.), C.W. Chen (NCU), S.Nishiura (Tokyo Gakugei Univ.), M. Isogai (Tokyo Univ.), T. Soyano(Tokyo Univ.), W.P. Chen (NCU) Y. Urata, T. Tamagawa (RIKEN), K.Y. Huang, W.H. Ip (NCU), Y. Qiu (BAO) and Y.Q. Lou(THCA) on behalf of the East Asian collaboration report: " We have observed the afterglow candidate of GRB 050319 (Rykoff et al. # 3116, Krimm et al. # 3117) using Kiso 1.05-m and Lulin 1-m telescopes starting at 2005 Mar. 19, 10:45 UTC (after end of twilight). We have imaged the optical candidate (Rykoff et al. # 3116) clearly in BVRI bands. Based on our preliminary photometry for R-band images, we have confirmed the decay of the optical candidate. Observation time and magnitudes are: Filter Exposure UT Mag. site R 300s 10:45 19.5 Kiso R 300s 11:28 19.5 Lulin R 300s 13:29 20.0 Kiso Further observations are in progress, this message may be cite." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3121 SUBJECT: GRB 050319: Optical observation DATE: 05/03/19 17:30:56 GMT FROM: Ken ichi Torii at RIKEN K. Torii (Osaka U.) reports "The error region of GRB 050319 (GCN 3117) was observed by the ART 14-inch telescope. BVRcIc imaging started at 2005 March 19, 11:24 UT and 60-s exposure in each filter was repeated. By stacking twenty Rc and twenty Ic frames obtained between 11:36 UT and 13:05 UT (Mean Epoch 12:20 UT), we note an enhancement of 2.3-sigma level at the position of the optical afterglow (GCN 3116). The enhancement in the stacked frame corresponds to 19.6 mag with reference to USNO-A2.0 red magnitude. Combining this magnitude and those reported in GCN 3116 and GCN 3120, the early optical afterglow of GRB 050319 decays with relatively shallow power-law index of t^(-0.6)." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3124 SUBJECT: GRB050319: BR optical photometry DATE: 05/03/20 06:17:12 GMT FROM: Alexei Pozanenko at IKI, Moscow D. Sharapov, M. Ibrahimov, R. Karimov, B. Kahharov (UBAI), A.Pozanenko (IKI), V.Rumyantsev (CrAO), G.Beskin (SAO) report: We observed afterglow candidate of Swift GRB050319 (Rykoff et al. GCN 3116, Krimm et al. GCN 3117) with 1.5m telescope of Mt.Maidanak high-altitude observatory. BR-band images were taken in two sets of observation on (UT) March 19, 17:14 --17:58 and 19:18 -- 21:45. We confirm a fading afterglow (Yoshioka et al. GCN 3120). Preliminary photometry against of USNO-B1.0 Catalog is following: Mean time Exposure Filter Mag. (UT) (s) Mar.19 17:28 900 B 20.85 Mar.19 17:31 1500 R 20.12 Mar.19 20:17 1800 B 21.29 Mar.19 20:16 4800 R 20.17 with typical magnitude error of less than 0.10. B-R at the two epochs marginally indicate color variation which is not typical for this phase of afterglow. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3125 SUBJECT: GRB 050319:Near IR afterglow DATE: 05/03/20 11:36:41 GMT FROM: Koshy George at PRL Koshy George,Jinesh Jain,N.M.Ashok,T.Chandrasekhar (Physical Research Laboratory,India) We report on the detection of near infrared afterglow of GRB 050319 using NICMOS camera coupled with 1.2m telescope of Physical Research Laboratory at Gurushikar, Mt.Abu, India. The observations started at 15:41:00 UT on 19 March in J-band filter at a 4'* 4' field of view shows a probable Infrared candidate at the error region of optical afterglow candidate (GCN 3116 & 3117). We had taken a net fourty minute exposure and the source which was present in our first 20s frame was found to be faded down to our observational limits with in 4min (four frames of each 60s exposure). Preliminary analysis and on comparison with two near by stars present in our field shows that the near infrared afterglow candidate corresponds to a J-band magnitude ~ 13 at 15:41:20 UT //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3126 SUBJECT: GRB 050319: NIR afterglow candidate DATE: 05/03/20 11:52:45 GMT FROM: Koshy George at PRL Koshy George, Jinesh Jain, N.M.Ashok, T.Chandrasekhar (Physical Research Laboratory, India) We report on the detection of near infrared afterglow of GRB 050319 using NICMOS camera coupled with 1.2m telescope of Physical Research Laboratory at Gurushikar, Mt.Abu, India. The observations started at 15:41:00 UT on 19 March in J-band filter at a 4'* 4' field of view shows a probable Infrared candidate at the error region of optical afterglow candidate (GCN 3116 & 3117). We had taken a net fourty minute exposure and the source which was present in our first 20s frame was found to be faded down to our observational limits with in 4min (four frames of each 60s exposure). Preliminary analysis and on comparison with two near by stars present in our field shows that the near infrared afterglow candidate corresponds to a J-band magnitude ~ 13 at 15:41:20 UT //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3127 SUBJECT: GRB050319: Radio Observations DATE: 05/03/20 18:10:48 GMT FROM: Alicia Soderberg at Caltech A. M. Soderberg (Caltech) reports on behalf of the Caltech-NRAO-Carnegie GRB collaboration: "Using the Very Large Array at 8.5 GHz, we observed the field of GRB050319 (GCN 3117) on 2005 Mar 20.03 UT. We do not detect a radio source at the position of the optical afterglow (GCN 3116). We place a (2-sigma) limit of 115 uJy. Further observations are planned." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3129 SUBJECT: GRB 050319: Swift-UVOT detection of the afterglow DATE: 05/03/21 00:38:06 GMT FROM: Martin Still at NASA/GSFC Swift SSC P. Boyd (GSFC/UMBC), S. T. Holland, M. Still (GSFC/USRA), W. Landsman (GSFC), S. Hunsberger (PSU), A. Breeveld (MSSL), P. Roming (PSU), K. Mason, P. Schady (MSSL), M. Ivanushkina (PSU), T. Poole (MSSL), C. Gronwall (PSU) A. Blustin (MSSL), P. Brown (PSU), S. Rosen, K. McGowan (MSSL), S. Koch (PSU), M. Carter, H. Huckle, M. De Pasquale (MSSL), P. Broos (PSU), T. Kennedy, P. Smith, B. Hancock (MSSL), H. Krimm (GSFC/USRA), J. Nousek (PSU), N. Gehrels (GSFC), on behalf of the Swift UVOT team. The Swift Ultra-Violet/Optical Telescope (UVOT) began settled observations of the field of GRB 050319 (Krimm et al; GCN 3117) at 09:32:48 UT, 90 after the BAT trigger. A comparison of the 100s finding chart (with mid-exposure 140s after the trigger) against the Digitized Sky Survey reveals a new source inside the BAT and XRT error circles at: RA = 10h 16m 47.76(3)s Dec = +43d 32m 54.9(5)s J2000 and consistent with the ROTSE-IIIb position reported by Rykoff et al. (GCN 3116) The V band magnitude is V = 17.5(1). The UVOT obtained a series of images of this burst with a variety of integration times. Mid-exposure times, Delta-T, with respect to the BAT trigger at 09:31:18 UT are measured in seconds. Observations with the V and B filters are listed below: Delta-T Exposure(s) Filter Mag 140 100 V 17.5 (Finding Chart) 380 80 B 18.8 600 80 V 18.4 1030 100 B 18.9 1250 100 V 19.2 5400 900 B 20.9 7080 700 V 20.2 17000 900 B 21.2 18700 700 V 20.6 No signal was detected in the U band in a total exposure time of 90s centered approximately 600s after the trigger with an upper limit of U = 19. We caution that the absolute magnitude scale is based on ground calibration and will require confirmation in flight. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3130 SUBJECT: GRB 050319 R band observations DATE: 05/03/21 17:45:03 GMT FROM: Kuntal Mishra at State Obs,Nainital,India Kuntal Misra, Atish P. Kamble and S. B. Pandey (ARIES Naini Tal), on behalf of larger Indian GRB collaboration We observed the optical afterglow candidate (GCN 3116) localized by Swift-BAT (GCN 3117) using the 1.04-m telescope at ARIES, Naini Tal starting around 2005 March 19, 16:09 UT. We acquired BVRI images under thin passing clouds. Our preliminary R-band photometry gives a magnitude of 19.92 +/- 0.08 at 2005 March 19, 17:16 UT after comparing with near by USNO-A2.0 stars. Further observations are in progress. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3131 SUBJECT: GRB050319: radio observation DATE: 05/03/21 18:07:49 GMT FROM: Guy Pooley at MRAO, Cambridge, UK Guy Pooley (MRAO, Cavendish Astrophysics, Cambridge) reports: Using the Ryle Telescope at 15 GHz in an observation of the field of GRB050319 (GCN3117) centred on 2005 Mar 21.0, we do not detect any radio emission; the formal measurement is 0.21 +- 0.23 (sigma) at the position of the optical afterglow (GCN3116). [GCN OPS NOTE (22mar05): Changed subject-line "090519" to "050319".] //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3132 SUBJECT: GRB050319: VLA Observations DATE: 05/03/21 18:39:50 GMT FROM: Alicia Soderberg at Caltech A. M. Soderberg (Caltech) reports on behalf of the Caltech-NRAO-Carnegie GRB collaboration: "Using the Very Large Array at 8.5 GHz, we observed again the field of GRB050319 (GCN 3117) on 2005 Mar 21.4 UT. We still do not detect a radio source at the position of the optical afterglow (GCN 3116). We place a (2-sigma) limit of 133 uJy at that position. Combining these data with those of our previous epoch (GCN 3127), we derive a deeper limit of 70 uJy (2-sigma rms) for the field." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3133 SUBJECT: Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319 DATE: 05/03/21 22:15:51 GMT FROM: David Burrows at PSU/Swift A. P. Beardmore, K. L. Page (U. Leicester), V. Mangano (INAF-IASF/Palermo), P. Romano (INAF-OAB), M. R. Goad, O. Godet, J. P. Osborne (U. Leicester), G. Chincarini, S. Campana (INAF-OAB), D. N. Burrows, J. L. Racusin (PSU), G. Cusumano, T. Mineo (INAF-IASF/Palermo), M. Perri, F. Tamburelli (ASDC), L. Angelini, F. Marshall, N. Gehrels (GSFC) report on behalf of the Swift XRT team: We report refined XRT source positions for GRB 050315 (GCN3094, GCN3097), GRB 050318 (GCN3111, GCN3113), and GRB 050319 (GCN3117), based on improved ground-based analysis of extended data sets from these three bursts. We find the following afterglow positions: GRB 050315: RA(J2000) = 20:25:53.9, Dec(J2000) = -42:36:01.4 (P. Romano), which is 2.3" from the optical counterpart (GCN3100). GRB 050318: RA(J2000) = 03:18:51.1, Dec(J2000) = -46:23:44.7 (V. Mangano), which is 1.1" from the optical counterpart (GCN3123). GRB 050319: RA(J2000) = 10:16:48.1, Dec(J2000) = +43:32:52.3 (K. Page), which is 3.1" from the optical counterpart (GCN3116). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3135 SUBJECT: GRB 050319: ROTSE-III Refined Analysis DATE: 05/03/22 02:19:44 GMT FROM: Robert Quimby at U of Texas/ROTSE R. M. Quimby, E. S. Rykoff, B. E. Schaefer, T. McKay, and S. A. Yost report on behalf of the ROTSE collaboration: ROTSE-IIIb, located at the McDonald Observatory, Texas, responded automatically to Swift GRB 050319 (Krimm et al., GCN 3117, GCN 3119) with the first 5-second exposure beginning Mar 19, 09:31:45.56 UT (Rykoff et al., GCN 3116), 27.1 seconds after the BAT trigger. The observing sequence consisted of ten 5-second and ten 20-second images followed by about 70 60-second exposures before clouds set in. All images are unfiltered and the average time between exposures was 9.5 seconds. We measured the afterglow flux in circular apertures relative to our deepest image, and calibrated the magnitude scale by adopting SDSS r-band values for our fiducial reference stars. Magnitudes on this system for our first 5, 20, and 60-second images are given below. Time (UT) mag +/- 09:31:45.56 16.16 0.17 09:34:09.95 17.22 0.20 09:39:05.24 17.58 0.18 The afterglow is detected in the first 30 images, and coadding the later exposures in groups of 5 to 10 also results in detections, making this one of the best sampled early light curves for any GRB. The afterglow is well fit by a t^(-alpha) power law with alpha=0.59 +/- 0.05, consistent with later R band observations reported in the GCN Circulars (GCNs 3120, 3121, 3124). Continuing this trend predicts the afterglow is currently brighter than 22nd magnitude. No host is present in the SDSS data at the location of the afterglow, which implies the redshift for this GRB is larger than 0.3. We also note the IR detection reported by George et al. (GCN 3125) gives a J-R color of about 7, and could suggest a high-z source. Spectral observations are encouraged to accurately determine the GRB redshift. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3136 SUBJECT: GRB 050319: Absorption redshift from the Nordic Optical Telescope DATE: 05/03/22 09:08:13 GMT FROM: Johan U. Fynbo at U.Copenhagen GRB 050319: Absorption redshift from the Nordic Optical Telescope Johan P. U. Fynbo, Jens Hjorth, Brian L. Jensen, Pall Jakobsson (Niels Bohr Institute), Palle Moller (ESO), Jyri Näränen (Nordic Optical Telescope) report: "Using ALFOSC on the Nordic Optical Telescope (NOT) we have obtained spectra of the afterglow of GRB 050319 (GCN 3116, 3117) on 2005, March 20 UT. We find several absorption features, including strong Lyman-alpha, OI+SiII, SiIV and CIV, corresponding to a redshift of z=3.24." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3139 SUBJECT: GRB050319: RTT150 Optical Observations DATE: 05/03/23 08:22:43 GMT FROM: Umit Kiziloglu at Middle East Tech.U,Phys.Dept U. Kiziloglu, S. Balman, A. Baykal (METU), Z. Aslan, I. Khamitov, K. Uluc (TUG), S. Evren (EgeU), A. Alpar (Sabanci U.), R. Burenin, M. Pavlinsky (IKI), R. Sunyaev (IKI, MPA), I, Bikmaev (KSU) report : We observed the field centered on the Swift GRB 041006 (Rykoff et al. GCN 3116, Krimm et al., GCN 3117, GCN 3119) with the TUG (TUBITAK National Observatory, Turkey) 1.5-m Russian-Turkish Telescope (RTT150). We obtained 8x300s 6x120s 3x60s R band images on 2005.03.19 starting at 17:26:36 UT using the imaging ANDOR CCD. The seeing was 1.8"-2.1". We further obtained 6x300 s R band images on 2005.03.20 and 2005.03.21 with RTT150. The seeing was poor with Moon. We calculated the R magnitudes below using the USNO B1.0 Catalog. Observation (UT) R_mag -------------------- ---------------------- 2005 March 19, 18:12 20.14 +/- 0.09 2005 March 21, 00:16 21.3 +/- 0.6 1 Sigma frame upper limit 2005 March 21, 17:58 21.1 +/- 0.3 This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3140 SUBJECT: GRB050319: optical observation, March 20-22 DATE: 05/03/24 14:36:37 GMT FROM: Alexei Pozanenko at IKI, Moscow D. Sharapov, M. Ibrahimov, R. Karimov, B. Kahharov (UBAI), A.Pozanenko (IKI), V.Rumyantsev (CrAO), G.Beskin (SAO) report: We continue observation (Sharapov et al. GCN 3124) of GRB050319 afterglow (Rykoff et al. GCN 3116, Krimm et al. GCN 3117) with 1.5m telescope of Maidanak Astronomical Observatory, Mt.Maidanak, Uzbekistan. R-band images were taken in several sets of observation on March 19-22. Preliminary photometry against of USNO-B1.0 Catalog is following: Mean time Exposure Filter Mag. (UT) (s) Mar.20 21:49 2640 R 21.62 (0.07) Mar.21 21:34 1560 R 21.67 (0.09) Mar.22 18:41 1260 R 21.27 (0.13) Observations obtained on March 22 are not compatible with power law index decay 1.59 (.05) for early and first day afterglow observations (Torii et al. GCN 3132, Quimby, GCN 3135) suggesting a presence of knee or re-brightening of the afterglow light curve. Excellent seeing conditions during the observations on Mar. 22 (~0.7") allow us to investigate some details of the field objects. In particular IDs (USNO-B1.0) 1335-0213759 and 1335-0213777 seem to be galaxies, and ID 1335-0213724 is a variable star. All above is leaving a few field stars for calibration. Deep field photometry for correct calibration would be encouraged. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3141 SUBJECT: GRB050319, color indices DATE: 05/03/25 10:50:15 GMT FROM: Rene Hudec at AIO <> V. Simon, R. Hudec (Astronomical Institute AV CR, Ondrejov, Czech Republic) and G. Pizzichini, N. Masetti (INAF/IASF Bologna, Italy) report: <> We have determined the color indices of the optical afterglow (OA) of GRB050319 in its very early phase from the available data (GCN 3124, 3129). The interpolation method described in Simon et al. (2001, A&A, 377, 450) was used. Since the Swift UVOT magnitudes need a confirmation of their calibration, we determined the indices separately for UVOT and ground-based observations. The indices of the OA from UVOT are: t-To=0.0044 d: B-V=0.68; 0.0119: -0.10; 0.0625: 0.85; 0.1968: 0.64, while those of the ground-based observations (GCN 3124) are: t-To(d)= 0.331 d: B-R=0.73; 0.448: 1.12. The typical error of these indices is about 0.10 mag. The Galactic reddening E(B-V)=0.011, determined from the maps by Schlegel et al. (1998, ApJ, 500, 525), is comparable to the errors of the measurements. We note that the variations in B-V, with a peak at t-To=0.01 days, are caused by a plateau in B while the V magnitude was already steadily decreasing. The last two measurements from UVOT can suggest that B-V reached the value roughly consistent with the typical one for the ensemble of 23 OAs, defined by Simon et al. (2001; 2004, AIP Conf. Proc., Vol.727, p.487), not later than at t-To=0.06 days. The indices of the OA of GRB050319 for t-To > 0.06 days thus appear to be plausibly consistent with the mean values of the ensemble (B-V)o=0.45+/-0.15, (B-R)o=0.86+/-0.17. This suggests that the shape of the spectrum of the afterglow of GRB050319 is similar to the other afterglows and that its intrinsic reddening (that is inside the host galaxy) must be again small (Simon et al. 2001; 2004, AIP Conf. Proc., Vol.727, p.487). Also the redshift of GRB050319 z=3.24 (GCN 3136) suggests that this GRB appears to be another member of the above-mentioned ensemble of the OAs with z < 3.5. The search for the host galaxy and the determination of its type are also encouraged. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3142 SUBJECT: GRB050319, optical observations DATE: 05/03/25 18:14:38 GMT FROM: Adalberto Piccioni at Astronomy, Bologna U. G. Greco, C. Bartolini, A. Guarnieri, A. Piccioni (Bologna University), P. Ferrero (Osservatorio e Universita' di Teramo), G. Pizzichini (IASF-CNR, Sezione di Bologna) and I. Bruni (Osservatorio di Bologna) report: We observed the error box of GRB050319 (SWIFT trigger 11162; Krimm et al., GCN 3117) in Rc light on March 20 in good sky conditions (seeing approx. 1.5 - 2 arcsec) but in presence of high contribution of moonlight with the 152 cm G.D. Cassini telescope of Bologna University, equipped with the BFOSC CCD imager. We got 4X1200s images with the following results: UT at start exposure Exposure (s) OT Rc mag 2005 March 20, 2:14 1200 19.58 (+- 0.18) 2005 March 20, 2:37 1200 19.66 (+- 0.16) 2005 March 20, 3:02 1200 19.67 (+- 0.16) 2005 March 20 3:25 1200 19.69 (+- 0.19) obtained using as comparisons the following objects extracted from the USNO A2 catalog: ID: 1275-07685084 ID: 1275-07684473 ID: 1275-07683651 ID: 1275-07685059 ID: 1275-07684793 ID: 1275-07685268 ID: 1275-07684751 From our images, by comparison with the R magnitudes reported by CGN 3124, 3139 and 3140 we infer a substantial rebrightening. An image of the OT is posted into a public directory from where it can be retrieved by sftp using hostname: ermione.bo.astro.it, username: publicGRB, password: GRB_bo and directory: GRB050319. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3153 SUBJECT: GRB050319: radio observation DATE: 05/03/28 16:09:53 GMT FROM: Vasilij Rumjantsev at CrAO A.Volvach (CrAO), A.Pozanenko (IKI) reports on behalf of CrAO-IKI-SAO GRB collaboration: We observed the error-box of GRB050319 (Krimm et al. GCN 3117) on March 21, and 24 at 2.3 GHz and 8.4 GHz with RT-22 of Crimean Astrophysical Observatory. Upper limits obtained for the afterglow position (Rykoff et al. GCN 3116) are approximately equal for both 2.3 GHz and 8.4 GHz frequencies: Mar. 21.69 (UT) 2 mJy (2 sigma) Mar. 24.67 (UT) 2 mJy (2 sigma) Results of observations are in an agreement with GCN 3132 (A. M. Soderberg) This message may be cited.