////////////////////////////////////////////////////////////////////// TITLE: GCN/HETE BURST POSITION NOTICE NOTICE_DATE: Wed 23 Jul 03 06:28:59 UT NOTICE_TYPE: HETE S/C_Alert TRIGGER_NUM: 2777, Seq_Num: 1 GRB_DATE: 12843 TJD; 204 DOY; 03/07/23 GRB_TIME: 23297.45 SOD {06:28:17.45} UT TRIGGER_SOURCE: Trigger on the 2-30 keV band. WXM_SIG/NOISE: 0.1 sig/noise on a 6.720 [sec] timescale SC_-Z_RA: 326 [deg] SC_-Z_DEC: -16 [deg] SC_LONG: 244 [deg East] WXM_CNTR_RA: 327.364d {+21h 49m 27s} (J2000), 327.415d {+21h 49m 40s} (current), 326.644d {+21h 46m 35s} (1950) WXM_CNTR_DEC: -27.528d {-27d 31' 41"} (J2000), -27.512d {-27d 30' 41"} (current), -27.762d {-27d 45' 42"} (1950) WXM_MAX_SIZE: 60.00 [arcmin] diameter WXM_LOC_SN: 3 sig/noise (pt src in image) WXM_IMAGE_SN: X= 3.2 Y= 2.2 [sig/noise] WXM_LC_SN: X= 5.2 Y= 4.5 [sig/noise] SUN_POSTN: 122.20d {+08h 08m 49s} +20.15d {+20d 08' 43"} SUN_DIST: 155.84 [deg] MOON_POSTN: 49.25d {+03h 16m 59s} +17.57d {+17d 34' 28"} MOON_DIST: 91.11 [deg] MOON_ILLUM: 32 [%] GAL_COORDS: 21.50,-49.82 [deg] galactic lon,lat of the burst ECL_COORDS: 320.18,-13.52 [deg] ecliptic lon,lat of the burst COMMENTS: Possible GRB. COMMENTS: Possible XRB. COMMENTS: WXM error box is circular; not rectangular. COMMENTS: WXM S/N is less than a reasonable value. ////////////////////////////////////////////////////////////////////// TITLE: GCN/HETE BURST POSITION NOTICE NOTICE_DATE: Wed 23 Jul 03 06:29:08 UT NOTICE_TYPE: HETE S/C_Update TRIGGER_NUM: 2777, Seq_Num: 2 GRB_DATE: 12843 TJD; 204 DOY; 03/07/23 GRB_TIME: 23297.45 SOD {06:28:17.45} UT TRIGGER_SOURCE: Trigger on the 2-30 keV band. WXM_SIG/NOISE: 0.1 sig/noise on a 6.720 [sec] timescale SC_-Z_RA: 326 [deg] SC_-Z_DEC: -16 [deg] SC_LONG: 244 [deg East] WXM_CNTR_RA: 327.422d {+21h 49m 41s} (J2000), 327.473d {+21h 49m 54s} (current), 326.701d {+21h 46m 48s} (1950) WXM_CNTR_DEC: -27.808d {-27d 48' 29"} (J2000), -27.792d {-27d 47' 28"} (current), -28.042d {-28d 02' 30"} (1950) WXM_MAX_SIZE: 60.00 [arcmin] diameter WXM_LOC_SN: 4 sig/noise (pt src in image) WXM_IMAGE_SN: X= 3.2 Y= 2.7 [sig/noise] WXM_LC_SN: X= 6.0 Y= 4.2 [sig/noise] SUN_POSTN: 122.20d {+08h 08m 49s} +20.15d {+20d 08' 43"} SUN_DIST: 155.73 [deg] MOON_POSTN: 49.25d {+03h 16m 59s} +17.57d {+17d 34' 28"} MOON_DIST: 91.15 [deg] MOON_ILLUM: 32 [%] GAL_COORDS: 21.09,-49.92 [deg] galactic lon,lat of the burst ECL_COORDS: 320.13,-13.80 [deg] ecliptic lon,lat of the burst COMMENTS: Possible GRB. COMMENTS: Possible XRB. COMMENTS: WXM error box is circular; not rectangular. COMMENTS: WXM S/N is less than a reasonable value. ////////////////////////////////////////////////////////////////////// TITLE: GCN/HETE BURST POSITION NOTICE NOTICE_DATE: Wed 23 Jul 03 06:30:37 UT NOTICE_TYPE: HETE S/C_Update TRIGGER_NUM: 2777, Seq_Num: 3 GRB_DATE: 12843 TJD; 204 DOY; 03/07/23 GRB_TIME: 23297.45 SOD {06:28:17.45} UT TRIGGER_SOURCE: Trigger on the 2-30 keV band. WXM_SIG/NOISE: 0.1 sig/noise on a 6.720 [sec] timescale SC_-Z_RA: 326 [deg] SC_-Z_DEC: -16 [deg] SC_LONG: 244 [deg East] WXM_CNTR_RA: 327.422d {+21h 49m 41s} (J2000), 327.473d {+21h 49m 54s} (current), 326.701d {+21h 46m 48s} (1950) WXM_CNTR_DEC: -27.808d {-27d 48' 29"} (J2000), -27.792d {-27d 47' 28"} (current), -28.042d {-28d 02' 30"} (1950) WXM_MAX_SIZE: 60.00 [arcmin] diameter WXM_LOC_SN: 4 sig/noise (pt src in image) WXM_IMAGE_SN: X= 3.2 Y= 2.7 [sig/noise] WXM_LC_SN: X= 6.0 Y= 4.2 [sig/noise] SUN_POSTN: 122.20d {+08h 08m 49s} +20.15d {+20d 08' 43"} SUN_DIST: 155.73 [deg] MOON_POSTN: 49.25d {+03h 16m 59s} +17.57d {+17d 34' 28"} MOON_DIST: 91.15 [deg] MOON_ILLUM: 32 [%] GAL_COORDS: 21.09,-49.92 [deg] galactic lon,lat of the burst ECL_COORDS: 320.13,-13.80 [deg] ecliptic lon,lat of the burst COMMENTS: Possible GRB. COMMENTS: Possible XRB. COMMENTS: WXM error box is circular; not rectangular. COMMENTS: WXM S/N is less than a reasonable value. ////////////////////////////////////////////////////////////////////// TITLE: GCN/HETE BURST POSITION NOTICE NOTICE_DATE: Wed 23 Jul 03 06:32:13 UT NOTICE_TYPE: HETE S/C_Last TRIGGER_NUM: 2777, Seq_Num: 4 GRB_DATE: 12843 TJD; 204 DOY; 03/07/23 GRB_TIME: 23297.45 SOD {06:28:17.45} UT TRIGGER_SOURCE: Trigger on the 2-30 keV band. WXM_SIG/NOISE: 0.1 sig/noise on a 6.720 [sec] timescale SC_-Z_RA: 326 [deg] SC_-Z_DEC: -16 [deg] SC_LONG: 244 [deg East] WXM_CNTR_RA: 327.422d {+21h 49m 41s} (J2000), 327.473d {+21h 49m 54s} (current), 326.701d {+21h 46m 48s} (1950) WXM_CNTR_DEC: -27.808d {-27d 48' 29"} (J2000), -27.792d {-27d 47' 28"} (current), -28.042d {-28d 02' 30"} (1950) WXM_MAX_SIZE: 60.00 [arcmin] diameter WXM_LOC_SN: 4 sig/noise (pt src in image) WXM_IMAGE_SN: X= 3.2 Y= 2.7 [sig/noise] WXM_LC_SN: X= 6.0 Y= 4.2 [sig/noise] SUN_POSTN: 122.20d {+08h 08m 49s} +20.15d {+20d 08' 43"} SUN_DIST: 155.73 [deg] MOON_POSTN: 49.25d {+03h 16m 59s} +17.57d {+17d 34' 28"} MOON_DIST: 91.15 [deg] MOON_ILLUM: 32 [%] GAL_COORDS: 21.09,-49.92 [deg] galactic lon,lat of the burst ECL_COORDS: 320.13,-13.80 [deg] ecliptic lon,lat of the burst COMMENTS: Possible GRB. COMMENTS: Possible XRB. COMMENTS: WXM error box is circular; not rectangular. COMMENTS: WXM S/N is less than a reasonable value. ////////////////////////////////////////////////////////////////////// TITLE: GCN/HETE BURST POSITION NOTICE NOTICE_DATE: Wed 23 Jul 03 09:47:25 UT NOTICE_TYPE: HETE Ground Analysis TRIGGER_NUM: 2777, Seq_Num: 5 GRB_DATE: 12843 TJD; 204 DOY; 03/07/23 GRB_TIME: 23297.45 SOD {06:28:17.45} UT TRIGGER_SOURCE: Trigger on the 2-30 keV band. WXM_SIG/NOISE: 0.1 sig/noise on a 6.720 [sec] timescale SC_-Z_RA: 325 [deg] SC_-Z_DEC: -16 [deg] SC_LONG: 244 [deg East] WXM_CNTR_RA: 327.215d {+21h 48m 52s} (J2000), 327.266d {+21h 49m 04s} (current), 326.494d {+21h 45m 59s} (1950) WXM_CNTR_DEC: -27.688d {-27d 41' 16"} (J2000), -27.671d {-27d 40' 16"} (current), -27.921d {-27d 55' 15"} (1950) WXM_MAX_SIZE: 18.82 [arcmin] diameter WXM_LOC_SN: 6 sig/noise (pt src in image) WXM_IMAGE_SN: X= 5.0 Y= 3.1 [sig/noise] WXM_LC_SN: X= 9.5 Y= 6.2 [sig/noise] SUN_POSTN: 122.20d {+08h 08m 49s} +20.15d {+20d 08' 43"} SUN_DIST: 155.94 [deg] MOON_POSTN: 49.25d {+03h 16m 59s} +17.57d {+17d 34' 28"} MOON_DIST: 91.29 [deg] MOON_ILLUM: 32 [%] GAL_COORDS: 21.22,-49.71 [deg] galactic lon,lat of the burst ECL_COORDS: 320.00,-13.63 [deg] ecliptic lon,lat of the burst COMMENTS: Definite GRB. COMMENTS: WXM error box is circular; not rectangular. COMMENTS: Burst_Validity flag is true. COMMENTS: WXM data refined since S/C_Last Notice. ////////////////////////////////////////////////////////////////////// TITLE: GCN/HETE BURST POSITION NOTICE NOTICE_DATE: Wed 23 Jul 03 13:38:19 UT NOTICE_TYPE: HETE Ground Analysis TRIGGER_NUM: 2777, Seq_Num: 6 GRB_DATE: 12843 TJD; 204 DOY; 03/07/23 GRB_TIME: 23297.45 SOD {06:28:17.45} UT TRIGGER_SOURCE: Trigger on the 2-30 keV band. WXM_SIG/NOISE: 0.1 sig/noise on a 6.720 [sec] timescale SC_-Z_RA: 324 [deg] SC_-Z_DEC: -16 [deg] SC_LONG: 244 [deg East] SXC_CNTR_RA: 327.374d {+21h 49m 30s} (J2000), 327.425d {+21h 49m 42s} (current), 326.654d {+21h 46m 37s} (1950) SXC_CNTR_DEC: -27.702d {-27d 42' 06"} (J2000), -27.685d {-27d 41' 06"} (current), -27.936d {-27d 56' 07"} (1950) SXC_MAX_SIZE: 4.00 [arcmin] diameter SXC_LOC_SN: 3 sig/noise (pt src in image) SUN_POSTN: 122.20d {+08h 08m 49s} +20.15d {+20d 08' 43"} SUN_DIST: 155.80 [deg] MOON_POSTN: 49.25d {+03h 16m 59s} +17.57d {+17d 34' 28"} MOON_DIST: 91.16 [deg] MOON_ILLUM: 32 [%] GAL_COORDS: 21.24,-49.86 [deg] galactic lon,lat of the burst ECL_COORDS: 320.13,-13.69 [deg] ecliptic lon,lat of the burst COMMENTS: Definite GRB. COMMENTS: SXC error box is circular; not rectangular. COMMENTS: Burst_Validity flag is true. COMMENTS: SXC data refined since S/C_Last Notice. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2312 SUBJECT: GRB030723, optical observations DATE: 03/07/23 21:38:26 GMT FROM: Arne A. Henden at USNO/USRA B. Monard (Bronberg Obs.) reports on behalf of the AAVSO International GRB network: Observations of the HETE XRF/GRB030723 (triger 2777) error circle were made with the Bronberg 0.30m telescope + unfiltered CCD. Ten 45-second exposures with UT midpoint of 030723.806 (12.9hrs after the burst) were stacked, with a limiting magnitude of 20.5CR (based on USNO-A red magnitudes). No new object is seen down to approximately CR=20.0 when comparing against a DSS2-red image. The AAVSO International GRB network is greatful for a generous grant from the Curry Foundation and to NASA for the financial support for the High Energy Workshops for Amateur Astronomers. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2313 SUBJECT: XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and DATE: 03/07/23 23:39:56 GMT FROM: George Ricker at MIT XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and SXC G. Prigozhin, N. Butler, G. Crew, J. Doty, A. Dullighan, R. Vanderspek, J. Villasenor, T. Cline, J. G. Jernigan, A. Levine, F. Martel, E. Morgan, G. Monnelly, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams; G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, and S. Woosley on behalf of the HETE Science Team; C. Barraud, M. Boer, J-F Olive, J-P Dezalay, and K. Hurley on behalf of the HETE FREGATE Team; T. Tamagawa, M. Suzuki, C. Graziani, Y. Shirasaki, T. Donaghy, M. Matsuoka, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, Y. Nakagawa, R. Satoh, Y. Urata, T. Yamazaki and Y. Yamamoto, on behalf of the HETE WXM Team; write: At 06:28:17.45 UTC (23297.45 s UT) on 23 July 2003, the HETE FREGATE, WXM, and SXC instruments detected an X-ray flash, designated XRF030723 (=H2777), located at high galactic latitude (b = 50 degrees). The burst triggered the WXM in the 2-25 keV energy band. The burst signal-to-noise was ~9. A GCN burst alert was issued 42s later, reporting a flight-derived WXM localization with a 30 arcmin radius (90% confidence). Ground analysis of the WXM data produced a localization that was reported in a GCN Notice at 09:47:25 UT. The WXM data provided a localization that can be expressed as a 90% confidence circle that is 9.4 arcminutes in radius and is centered at-- WXM-ground: RA= +21h 48m 52s, Dec= -27d 41' 16" (J2000) Ground analysis of the SXC data provided an initial localization that was disseminated as a GCN Notice at 13:38:19 UT. A refined SXC localization can be expressed as a 90% confidence circle that is 2 arcmin in radius and is centered at-- SXC-Ground: RA= +21h 49m 27.4s, Dec= -27d 42' 01" (J2000) The burst duration (t90) in the 7-30 keV band was ~23 s. A total of 1210 counts were detected by Fregate during that interval, corresponding to a fluence of ~2 x 10-7 ergs cm-2. The peak flux in a 1.2 s bin was >3 x 10-8 ergs cm-2 s-1 (ie >0.9 x Crab flux) in the same energy band. In the 30-400 keV band, the fluence was < 0.7 x 10-7 ergs cm-2, which is < 0.4 times the fluence in the 7-30 keV band; thus we conclude that H2777 is an X-ray flash. A light curve and finding chart for XRF030723 is provided at the following URL: http://space.mit.edu/HETE/Bursts/GRB030723 This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2314 SUBJECT: XRF 030723, optical observations DATE: 03/07/23 23:55:59 GMT FROM: Alberto Castro-Tirado at LAEFF-INTA XRF 030723, optical observations ------------------------- A. de Ugarte (IAA-CSIC, Granada), P. Tristram (Univ. of Auckland), T. Sekiguchi (Univ. of Nagoya), M. Jelinek (ASU-CAS, Obs. Ondrejov), J. Gorosabel (IAA-CSIC and STScI, Baltimore), S. Guziy (IAA-CSIC), J. M. Castro Cerón (STScI), P. Kilmartin (Mt. John Obs.), Ph. Yock (Univ. of Auckland) and A. J. Castro-Tirado (IAA-CSIC) communicate: "Following the detection of the X-ray flash 030723 by HETE-2, we have imaged the entire error box with the 0.6-m telescope (+MOA camera) at Mt. John Observatory in wide R- and B-band filters (3 x 300-s each) starting on July 23.59 UT (i.e. 7.6 hr after the event). Comparison of a single R-band frame with the DSS-2 (R- -band) reveals no optical transient down to the DSS-2 limiting magnitude." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2315 SUBJECT: XRF030723, optical observations DATE: 03/07/24 05:25:58 GMT FROM: Weidong Li at UC Berkeley KAIT/LOSS W. Li, R. Chornock, A. V. Filippenko, and S. Jha (UC Berkeley) report: The Katzman Automatic Imaging Telescope (KAIT) responded to GRB 030723 (HETE Trigger #2777) automatically. The first four alerts issued via GCN at 6:29 UT, 6:37 UT, 6:43 UT, and 6:45 UT were not observed due to altitude limits, and we remotely (but manually) obtained 8 images starting at 7:38 UT (about 1.2 hours after the burst), covering a 12'.5 x 12'.5 region centered on R.A. = 21:49:41, Decl. = -27:48:29 (J2000). KAIT responded to the alert issued via GCN at 9:47 UT (3.3 hours after the burst) automatically, and obtained 9 images covering a 12'.5 x 12'.5 region centered on R.A. = 21:48:51, Decl. = -27:41:16 (J2000). The alert issued at 13:38 UT was not observed due to bright dawn. Visual inspection of the images reveals no obvious new source compared with the DSS II (red) to a limiting magnitude of 19.0 - 20.0 (the images have different exposure times). Specifically, the images taken around 7:38 UT covered about 50% of the error circle of the ground analysis burst position issued at 13:38 UT via GCN. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2316 SUBJECT: XRF 030723, optical observations DATE: 03/07/24 17:17:34 GMT FROM: Howard E Bond at STScI Howard E. Bond (Space Telescope Science Institute) reports: The SXC error circle of XRF 030723 (HETE Burst H2777) was imaged with the SMARTS Consortium 1.3m reflector at Cerro Tololo on 2003 July 24.080, 24.173, and 24.281. The 6'x6' CCD field was centered at RA= 21h 49m 27.4s, Dec= -27d 42' 01" (J2000), and R-band exposures of 3x300 sec were taken at each epoch. Visual inspection of the images shows no new sources compared to the second-epoch Digitized Sky Survey red images, nor any obviously variable fainter objects. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2317 SUBJECT: XRF030723, BVRcIc field photometry DATE: 03/07/24 19:18:06 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 11x11 arcmin field centered at the coordinates of the SXC error box for the HETE burst XRF030723 (Prigozhin et al., GCN 2313) 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/grb030723.dat The astrometry in this file is based on linear plate solutions with respect to UCAC2. The external errors are less than 100mas. However, this field was observed at high airmass and with incoming clouds, so the photometric zeropoint accuracy is about 0.03mag with the potential of a larger systematic error. We do not intend to reobserve this field unless an optical transient is discovered. As always, however, you should check the dates on the .dat file prior to final publication in case further observations are made. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2318 SUBJECT: XRF030723, ROTSE-III Early Observations DATE: 03/07/24 19:48:57 GMT FROM: Don Smith at U michigan D. A. Smith (U. of Michigan) & R. Quimby (U. of Texas) report on behalf of the ROTSE collaboration: The ROTSE-IIIb instrument at McDonald Observatory, Texas, responded automatically to HETE-2 alert 2777, and began taking images within 5 s of when the alert was distributed. The first exposure began 47 seconds after the burst trigger time. All objects in the SXC 2' (radius) error circle that appear in more than four individual ROTSE images match to sources in the USNO 2.0 catalog. Unfiltered limiting magnitudes, calibrated to USNO R-band, for the first ten (5-s) images were around 16.5, for the second ten (20-s) images around 17.5, and for the next 40 (60-s) images around 18.0. We then co-added sets of ten frames each to drive the limiting magnitudes down to 18.1, 18.7, and 19.1, respectively. We also co-added the first twenty frames as a check against false positives in the first two co-added images. Only two non-USNO sources within the error circle appear in more than the first of the co-added, composite images. We find no sources that appear in the five later co-adds that are not in the first one. Both of the non-USNO sources in the first image are dimmer in the second and third images, and both vanish by the fourth image. Neither source appears to be in the DSS or the 2MASS J and K archival images of this field, and neither source appears in images taken the following night (to a limiting magnitude of 18.6) at 0.95 d after the burst. One of the sources is too close to a USNO-cataloged star for SExtractor to de-blend the two. The star is at coordinates 21h 49m 24s.8, -27o 40' 10".16 (J2000.0), and its derived ROTSE magnitude (which would contain emission from both sources) fades by 1.6 mag from 17.3+-0.1 to 18.9+-0.2 as the nearby source (which is about 7.5" East and 3" South) disappears. The following night, this star was measured at 18.9+-0.2. The second source was isolated, and we derive the following light curve: R.A. Dec. (J2000.0) Magnitude 21h 49m 24s.379 -27o 40' 35".04 17.9+-0.2 18.2+-0.2 18.2+-0.1 > 19.1 > 19.1 > 19.1 (Time from burst) (47.3 s) (191.9 s) (8.1 m) (19.7 m) (31.3 m) (42.9 m) We cannot at this time determine if either of these sources is related to the HETE-2 event. Images and finding charts can be found at http://grad40.as.utexas.edu/~quimby/HETE2777 //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2319 SUBJECT: XRF030723, BVRcIc field photometry correction DATE: 03/07/24 20:05:06 GMT FROM: Arne A. Henden at USNO/USRA After reinspection of the data, it was found that the photometric calibration field center is not at the SXC coordinates, but rather 20 timesec (=267 arcsec) to the east due to operator error. The SXC localization center is present in the dataset, but the Western part of the error circle was missed. We apologize for the miscentering. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2320 SUBJECT: XRF030723 (= H2777): Chandra Observations Scheduled DATE: 03/07/25 00:11:53 GMT FROM: George Ricker at MIT XRF030723 (= H2777): Chandra Observations Scheduled G. Ricker, P. Ford, N. Butler, R. Vanderspek, J. Villasenor (MIT); D. Lamb (U. Chicago); G. Garmire (PSU); L. Piro (CNR); and J.G. Jernigan (UCB), on behalf of a Chandra GRB ToO Team, write: Chandra target-of-opportunity observations of the HETE SXC error circle for XRF030723 (= H2777: Prigozhin et al, GCN 2313) have been approved and scheduled. The first epoch observation will commence at 10h UT on 25 July, with a second epoch observation ~1 week later. The scheduling of contemporaneous observations at other wavelengths, especially deep initial epoch optical and IR observations, is strongly encouraged. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2321 SUBJECT: XRF030723: optical observations DATE: 03/07/25 16:20:25 GMT FROM: Brian Lindgren Jensen at U.of Copenhagen B. L. Jensen (U. Copenhagen), J. Gorosabel (IAA-CSIC/STScI), J. Hjorth, C. Vinter (U. Copenhagen), J. P. U. Fynbo (U. Aarhus), P. M. Vreeswijk (ESO Chile) report: "R-band exposures covering the 2' radius HETE-2 SXC error circle of XRF 030723 (Prigozhin et al., GCN #2313) were obtained at the Danish 1.5-m telescope (ESO La Silla) on July 24.3 and July 25.3 2003 UT. In the combined images, reaching limiting magnitudes of R ~ 24, no counterpart to the first ROTSE-III source (Smith & Quimby, GCN #2318) is apparent. At RA(J2000.0) = 21 49 24.54, Dec (J2000.0) = -27 40 35.0, 2.1" from the reported location of the second ROTSE-III source, an object with R = 23.2 +- 0.3 is detected (photometry based on the calibration provided by Henden (GCN #2317)). The object is unresolved in 1.3" seeing and appears to be constant in brightness between the two epochs. Images are posted at http://www.astro.ku.dk/~brian_j/grb/grb030723 " //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2323 SUBJECT: XRF030723: Palomar observations and proposed counterpart DATE: 03/07/26 02:11:08 GMT FROM: Derek Fox at CIT D.B. Fox, D.L. Kaplan, B. Cenko, and S.R. Kulkarni (Caltech), with A. Nechita (Harvard), report on behalf of the Caltech-NRAO GRB Collaboration: "We have observed the HETE-2 SXC localization region for XRF030723 (Prigozhin et al., GCN #2313) with the 60-inch and 200-inch (Hale) telescopes on Mt. Palomar, on two successive nights commencing at approximately July 24.4 UT and July 25.4 UT. 60-inch observations were made in R-band with CCD13; 200-inch observations were made in Ks-band with WIRC. We have photometered these data against the USNO and 2MASS catalogs; limiting magnitudes for our exposures are approximately R~22.8 and Ks~19.4 on July 24.5 UT (mean epoch), and R~22.5 and Ks~19.0 on July 25.5 UT, respectively. "Comparison of the two epochs of R-band imaging reveals a stationary, point-like, fading source with magnitudes R~21.3 on July 24.5 and R~22.4 (near the limit of detection) on July 25.5. This source is also detected in our July 24.5 Ks-band image with Ks~18.65; it is not detected in our July 25.5 Ks-band image to the Ks~19.0 limit. The coordinates of the source, referenced to the GSC 2.2, are: RA 21:49:24.40, Dec -27:42:47.4 (J2000) with an uncertainty of less than 0.5" in each coordinate. Given the pronounced fading of the source we suggest that it is likely to be the optical counterpart of XRF030723. Images of the field and proposed counterpart will be provided soon at the webpage: http://www.astro.caltech.edu/~derekfox/xrf030723/ //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2325 SUBJECT: GRB030723: Upper limits from historical observations DATE: 03/07/26 06:44:24 GMT FROM: Michael Wood-Vasey at UC Berkeley/LBNL/SNfactory GRB030723: Upper limits from historical observations. W. M. Wood-Vasey, Lawrence Berkeley National Laboratory, using images obtained by R. Bambery, S. Pravdo, M. Hicks, and K. Lawrence (Near-Earth Asteroid Tracking project, Jet Propulsion Laboratory), reports historical upper limits for the optical transient for GRB 030723 of Fox et. al (GCN #2323) from images taken with the Palomar Oschin 1.2-m telescope from 2001 Aug 30 -- 2002 Sep 9. A co-addition of these images (taken 2001 Aug 30, Oct 8, 2002 Jul 29, Aug 13, Aug 20, Sep 9) shows nothing at this location to a combined limiting unfiltered magnitude of 21.62 (S/N = 3). The co-addition is available at: http://supernova.lbl.gov/~wwoodvas/GRB/#GRB030723 The quoted magnitude represents a calibration of the unfiltered NEAT observations to the observed stars in the 0.25 sq. deg field of the component images to the "red" USNO-A1.0 catalog. This message may be cited. All dates UT. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2326 SUBJECT: Magellan Observations of XRF030723 (=H2777) DATE: 03/07/26 15:28:55 GMT FROM: George Ricker at MIT Magellan Observations of XRF030723 (=H2777) A. Dullighan, N. Butler, R. Vanderspek, J. Villasenor, and G. Ricker (MIT) write: We have observed the SXC error circle for the HETE-discovered X-ray flash XRF030723(=H2777; Prigozhin et al, GCN 2313) with the LDSS2 instrument on the 6.5m Magellan Clay telescope at Las Campanas Observatory in Chile. Four 6 minute Harris R-band exposures were taken in an interval centered on July 24.31 UT, extending from 24.8 h to 25.2 hours after the burst. The seeing was ~0.6 arcsec. Coaddition of the images gives a limiting magnitude of R = 24.5 magnitudes. We detect the suggested optical counterpart (Fox et al., GCN 2323) of GRB 030723 at R = 21.13 +/- 0.05 magnitudes. Combining our photometry with that of Fox et al, we estimate a power law decay index of 1.6. Our measurements have been calibrated against the recent USNO photometry data reported by Henden in GCN 2317. We gratefully acknowledge observational assistance by A. McWilliam and D. Osip. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2327 SUBJECT: XRF 030723: VLT spectra DATE: 03/07/26 16:07:13 GMT FROM: Jens Hjorth at U.Copenhagen J. P. U. Fynbo (U. Aarhus), J. Hjorth (U. Copenhagen), J. Gorosabel (IAA-CSIC/STScI), P. M. Vreeswijk (ESO Chile), J. E. Rhoads (STScI), on behalf of GRACE, report: "We have obtained VLT spectra of the candidate afterglow of XRF 030723 (Fox et al. GCN #2323). 22 600-sec spectra covering 3650 - 7500 A at 13 A resolution were obtained with FORS1/UT1 starting on July 26.25 2003 UT. A preliminary reduction of the spectra indicates a blue, featureless continuum with no obvious absorption or emission features. The apparent absence of absorption lines may indicate a low redshift or a low-density environment. The absence of a Lyman Forest suggests a redshift below 2.1. A detailed analysis is in progress. We thank the Paranal Observatory staff for efficiently conducting the reported service-mode observations." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2328 SUBJECT: XRF030723(=H2777): Chandra Observations DATE: 03/07/26 17:38:58 GMT FROM: George Ricker at MIT XRF030723(=H2777): Observations with the Chandra X-ray Observatory N. Butler, P. Ford, G. Ricker, R. Vanderspek, J. Villasenor (MIT); D. Lamb (U. Chicago); G. Garmire (PSU); L. Piro (CNR); and J.G. Jernigan (UCB), on behalf of a Chandra GRB ToO Team, write: On 25 July 2003, the Chandra Observatory targeted the field of XRF030723, an X-ray flash localized by the HETE satellite (=H2777; Prigozhin et al, GCN 2313). The 25 ksec observation spanned the interval 09:52-17:05 UT on 25 July, 51.4 - 59.0 hours after the burst. The SXC error circle from Prigozhin et al. was completely contained within the field-of-view of the Chandra ACIS-I array. Within the SXC error circle, we detect 3 sources in the 0.5-8 keV band: # Chandra Name RA DEC Cts 1 CXOU J214924.4-274248 21 49 24.421 -27 42 48.00 78 3 CXOU J214926.9-274146 21 49 26.891 -27 41 45.92 19 4 CXOU J214928.7-274211 21 49 28.724 -27 42 11.47 16 The brightest object within the SXC error circle, Chandra Source #1, lies 62" from the center of the SXC error circle, and is within 0.7" of the optical transient reported by Fox et al. (GCN 2323). We estimate a position uncertainty of 1.4" for the Chandra sources. Astrometry was performed using six stars from the USNO-A2 catalog. The Chandra results provide further evidence that the optical transient reported by Fox et al. (GCN 2323; see also Wood-Vasey et al., GCN 2325) and confirmed by Dullighan et al. (GCN 2326) is indeed the counterpart and afterglow of XRF030723. We gratefully acknowledge the timely assistance of Roger Brissenden and the observatory staff at the Chandra Science Center in arranging for the acquisition and preliminary processing of these data. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2329 SUBJECT: XRF 030723: confirmation of fading optical counterpart DATE: 03/07/26 17:57:23 GMT FROM: Howard E Bond at STScI Howard E. Bond (Space Telescope Science Institute) reports: As noted in (GCN #2316) the error circle of XRF 030723 was imaged with the SMARTS Consortium 1.3m reflector at Cerro Tololo on UT 2003 July 24.080, 24.173, and 24.281. An additional observation was obtained at UT 2003 July 25.414. R-band exposures of 3x300 sec were taken at each epoch The fading of the optical transient reported by Fox et al. (GCN #2323) is confirmed, albeit at low S/N. At July 24.080 the source was unfortunately located on a low-sensitivity region of the CCD. On July 24.173 and 24.281 it had R magnitudes of 21.0 and 20.9 (calibrated against a Landolt standard field, but with uncertainties of at least 0.1 mag). On July 25.414 the transient had faded below detectability and was at least 1 mag fainter than on the previous night. I thank Rebeccah Winnick, David Gonzalez, and Juan Espinoza for arranging and executing the observations on very short notice. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2330 SUBJECT: XRF030723 Radio Observations DATE: 03/07/27 21:01:06 GMT FROM: Alicia Soderberg at Caltech A. M. Soderberg and E. Berger (Caltech) with D. A. Frail (NRAO) report on behalf of the Caltech-NRAO GRB Collaboration: "We have observed the field of XRF030723 with the Very Large Array on July 26.42 UT at 8.46 GHz. We do not detect a radio counterpart to the optical transient reported by Fox et al. (GCN #2323). The 3 sigma detection limit at the position of the optical afterglow is 180 microJy." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2338 SUBJECT: XRF030723: Re-analysis of ROTSE-III early images DATE: 03/07/30 17:33:21 GMT FROM: Don Smith at U michigan D. A. Smith, C. W. Akerlof (U. of Michigan) and R. Quimby (U of Texas Austin) report on behalf of the ROTSE collaboration: We have re-analyzed the ROTSE-III early observations of event 030723 (See Smith & Quimby, GCN Circ. #2318 for details on the ROTSE observations) after the report of the counterpart candidate discovered by Fox et al. (GCN Circ. #2323). We performed a fit to a template PSF placed at a list of targets selected from Henden's photometry report (GCN Circ. #2317). We find no convincing evidence for a detection of the OT in the first four of our images, but the last two images do yield marginal possible detections. We derive 19.5+-0.4 for the fifth image (S/N=2.7) and 19.3+-0.4 for the sixth (S/N=3.1). We derive the following 2-sigma upper limits on the OT magnitude for each image, as calibrated to the R band values given by Henden: Time from burst (min): 0.79 3.2 8.1 19.7 31.3 42.9 R band magnitude : >19.0 >19.7 >19.1 >19.5 >18.9 >18.8 Note that these numbers are not limiting magnitudes for each image but upper limits to the brightness of an object at the OT location. Also, the ROTSE images are unfiltered, and since no color information is available for the early afterglow, we have not applied any color correction to this calibration. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2336 SUBJECT: XRF030723 (=H2777): Second Epoch Magellan Observations DATE: 03/07/29 19:59:50 GMT FROM: Roland Vanderspek at MIT Second Epoch Magellan Observations of XRF030723 (=H2777) A. Dullighan, N. Butler, R. Vanderspek, J. Villasenor, and G. Ricker (MIT) write: We have observed the SXC error circle for the HETE-discovered X-ray flash XRF030723 (=H2777; Prigozhin et al, GCN 2313) with the MagIC instrument on the 6.5m Magellan Clay telescope at Las Campanas Observatory in Chile. Two 200 second, Harris R-band exposures were taken in an interval centered on July 28.385 UT, at 5.13 days after the burst. The seeing was ~0.8 arcsec. Coaddition of the images gives a limiting magnitude of R = 24.3. We detect the optical counterpart (Fox et al., GCN 2323) of GRB 030723 at R = 24.2 +/- 0.3. Combining our photometry with that available from the GCN Circulars (Bond, GCN 2329; Dullighan et al., GCN 2326; Fox et al., GCN 2323), we estimate a late time power law decay index of ~2, and an early power law decay of 0.9. The break in the light curve is between 30-50 hours after the burst. Our measurements have been calibrated against the USNO photometry data reported by Henden in GCN 2317. A plot of this light curve can be seen at: http://space.mit.edu/HETE/Bursts/GRB030723/ We gratefully acknowledge observational assistance by Matthew J. Holman and Jeff McClintock. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2343 SUBJECT: XRF030723, BVRcIc field photometry update DATE: 03/08/06 15:50:41 GMT FROM: Arne A. Henden at USNO/USRA A. Henden (USRA/USNO) reports on behalf of the USNO GRB team: Because an optical afterglow (Fox et al., GCN 2323) has been discovered for the HETE XRF030723 (Prigozhin et al., GCN 2313), we have updated our field photometry file (Henden GCN 2317) to include a total of 3 photometric nights. The last two nights were repositioned so that the field center corresponds to the SXC error circle center, with the OT therefore only a couple of arcmin from the calibration field center. This file can be found at: ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb030723.dat Mean photometric errors are under 0.02mag and mean coordinate errors (UCAC2) are less than 100mas. No changes are expected beyond this point. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2345 SUBJECT: XRF 030723: Detection of a rebrightening in the optical afterglow DATE: 03/08/06 18:38:00 GMT FROM: Jens Hjorth at U.Copenhagen J. P. U. Fynbo (U. Aarhus), J. Hjorth (U. Copenhagen), J. Gorosabel (IAA-CSIC/STScI), B. L. Jensen (U. Copenhagen), M. I. Andersen (AIP), R. A. M. J. Wijers (U. Amsterdam), C. Kouveliotou (NASA/MSFC), on behalf of GRACE, report: "We have monitored the afterglow of XRF 030723 (Prigozhin et al. GCN #2313; Fox et al. GCN #2323; Butler et al. GCN #2328) with the ESO VLT. Between Aug 3.2 UT and Aug 6.3 2003 UT the optical afterglow brightened by 1.0 mag to R ~ 24.3. If this is due to the emergence of a supernova it would strengthen the link between GRBs and XRFs. It would also indicate a fast rise for the supernova and a relatively low redshift for XRF 030723, z < 1, consistent with the earlier spectroscopic constraints (Fynbo et al. GCN #2327). Alternatively, we may be seeing a rebrightening due to late energy injection (refreshed shock). Continued spectroscopic and photometric monitoring is planned. Images are posted at http://www.astro.ku.dk/~brian_j/grb/grb030723 We thank the Paranal Observatory staff for efficiently conducting the reported service-mode observations." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2347 SUBJECT: XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed DATE: 03/08/07 01:27:59 GMT FROM: George Ricker at MIT XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed N. Butler, P. Ford, G. Ricker, R. Vanderspek, J. Villasenor (MIT); D. Lamb (U. Chicago); G. Garmire (PSU); L. Piro (CNR); and J.G. Jernigan (UCB), on behalf of a Chandra GRB ToO Team, write: On 4 August 2003, the Chandra Observatory targeted the field of XRF030723, an X-ray flash localized by the HETE satellite (=H2777; Prigozhin et al, GCN 2313). The duration of the observation was 85 ksec, and it was a followup to the 25 ksec observation reported by Butler et al. in GCN 2328. The observation spanned the interval 4 August 22:22 UT to 5 August 22:27 UT, 12.66 to 13.67 days after the burst. The SXC error circle from Prigozhin et al. was completely contained within the field-of-view of the Chandra ACIS-S3 chip. Within the SXC error circle, the three X-ray sources from GCN 2328 are detected. Only source #1 is observed to vary in flux at a significance level of >1 sigma. We detect 74 counts in the 0.5-8.0 keV band, corresponding to a >7-sigma significance decrease (i.e. factor of ~6) in flux since the first epoch observation. We are thus extremely confident that source #1 is the X-ray counterpart to XRF030723 and is the counterpart to the optical source discovered by Fox et al. (GCN 2323). If we jointly fit the counts from the first and second Chandra epochs, we find that the data are well described by a power-law with absorption fixed at the Galactic value in the source direction (chi^2 = 8.9 for 9 [12-3] degrees of freedom). The best fit photon number index (for both epochs) is gamma = 1.9 +/- 0.3, which is a typical value for the X-ray afterglows of long duration GRBs. Using this model, we find that the first epoch flux is ( 2.2 +/- 0.3 ) x 10-14 erg cm-2 s-1 (0.5-8.0 keV band), while the second epoch flux is ( 3.5 +/- 0.5 ) x 10-15 erg cm-2 s-1 (0.5-8.0 keV band). The decrease in flux between the two epochs can be described by a power-law with a decay index of alpha= -1.0 +/- 0.1. This value of alpha is consistent with the power-law decline reported in the optical by Dullighan et al. (GCN 2336) for <~1.5 day after the GRB; however, the index is considerably flatter than the index at t>1.5 days reported by Dullighan et al. This flatter X-ray decay may possibly be related to the rebrightening of the optical afterglow reported by Fynbo et al. (GCN 2345). We gratefully acknowledge the timely assistance of the observatory staff at the Chandra Science Center in arranging for the acquisition and preliminary processing of these data. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2403 SUBJECT: XRF 030723: Detection of the likely host galaxy DATE: 03/09/25 15:13:29 GMT FROM: Johan U. Fynbo at IFA,U of Aarhus Johan P. U. Fynbo (U. of Aarhus), Jens Hjorth, Brian L. Jensen (U. of Copenhagen), Jesper Sollerman (U. of Stockholm), Michael I. Andersen (AIP, Potsdam), Javier Gorosabel (STScI) report on behalf of the GRACE collaboration: "We have observed the field of XRF 030723 (=HETE trigger 2777, GCN 2320) with the FORS1 optical camera on the ESO VLT on September 24. In a deep (about 1 hr) R-band image with a mean seeing of 0.68 arcsec we detect a very faint, extended source at the position of the optical afterglow (GCN 2323). The galaxy has a position angle of about 90 degrees EofN. We interpret this as the likely host galaxy of XRF 030723. The magnitude of the galaxy is about R=26.8+/-0.4. An image of the galaxy can be seen at: http://www.astro.ku.dk/~brian_j/xrf/xrf030723. We acknowledge excellent support from the Paranal staff, in particular Poshak Gandhi." -- Johan Fynbo //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2412 SUBJECT: XRF 030723: Subaru Optical Observations DATE: 03/10/08 02:31:38 GMT FROM: Nobuyuki Kawai at Tokyo Tech N. Kawai, G. Kosugi, Y. Komiyama, H. Furusawa, Y. Urata, and T. Yamada on behalf of the Subaru GRB team report: "We have observed the field of XRF030723 (=H2777, GCN 2320) with the Subaru Prime Focus Camera on 2003 September 29 - October 3 UT in V, Rc, Ic, and z' bands. We detected an unresolved source at the position of the proposed host galaxy (Fynbo et al. GCN 2403) in Rc, Ic and z' bands. With the preliminary analysis, the magnitude of the source was R=27.6 +/- 0.4 (2.4 hour exposure, mean seeing 0.7 arcsec). It has a red color, and we were not able to obtain significant detection of the source with the 1.7 hour exposure in V band. The images are posted at http://www.naoj.org/staff/george/Distribute/XRF030723/XRF030723.html."