//////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3430 SUBJECT: GRB 050520 - A long GRB detected with INTEGRAL DATE: 05/05/20 01:07:08 GMT FROM: Diego Gotz at IASF-CNR D. Gotz, S. Mereghetti (IASF, Milano), N. Mowlavi, S. Shaw, M. Beck (ISDC, Versoix) and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: A 80 s long GRB has been detected by IBAS in IBIS/ISGRI data at 00:05:53 on May 20 2005. Its refined coordinates (J2000) are: RA: 192.5087 [degrees] DEC: +30.4506 [degrees] with an uncertainty of 1.5 arcmin (90% c.l. radius). Its preliminary peak flux (20-200 keV, 1s integration time) is about 0.7 ph (5E-08 erg)/cmsq/s. Its fluence (20-200 keV, 80 s integration time) is 28.6 ph (2.4E-06 erg)/cmsq. A plot of the multi peaked light curve will be posted at http://ibas.mi.iasf.cnr.it/IBAS_Results.html Note that this burst is located at high galactic latitude (b=+86 deg) and not affected by Galactic absorption. It is therefore a good target for optical follow-up searches. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3431 SUBJECT: GRB 050520: BART optical limit DATE: 05/05/20 01:37:11 GMT FROM: Martin Jelinek at Inst.Astrophys.Andalucia,Granada Martin Jelinek (IAA Granada, Spain), Martin Nekola, Petr Kubanek, Filip Munz, Jan Strobl and Rene Hudec (ASU AV CR Ondrejov, Czech Republic) report: Robotic telescope BART located at Astronomical Institute in Ondrejov has observed the errorbox of the INTEGRAL trigger 2505 15 minutes after the GRB time. We do not detect any new source within the given errorbox down to limiting magnitude V=14. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3432 SUBJECT: GRB 050520: OSN optical observations DATE: 05/05/20 01:50:54 GMT FROM: Alberto Castro-Tirado at LAEFF-INTA A. de Ugarte Postigo, A. J. Castro-Tirado, A. Sota, M. Jelínek, J. Gorosabel and S. Guziy (IAA-CSIC Granada) report: "Following the detection by INTEGRAL of GRB 050520 (Gotz et al. GCN Circ. 3430), we have taken images in the VRI bands with the 1.5m telescope at IAA's Observatorio de Sierra Nevada, starting at 00:39 UT (i.e. 30 minutes after the event). The co-add of the first three I-band frames (3 x 300 s exposure time) reveals no optical counterpart in the 1.5' radius error box down to the DSS2 limiting magnitude. Further analysis is ongoing." This message can be quoted. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3433 SUBJECT: GRB 050520: VLT/ULTRACAM observations DATE: 05/05/20 03:43:33 GMT FROM: Paul Vreeswijk at ESO P. Vreeswijk (ESO), T. Marsh (U. Warwick), S. Littlefair, V. Dhillon (U. Sheffield), K. O'Brien (ESO) report on behalf of a larger collaboration: We observed the central 2.3'x2.3' of the field of GRB 050520 (INTEGRAL trigger 2505) with the high-time resolution imaging instrument ULTRACAM, currently attached to the visitor focus of VLT/Melipal. The ULTRACAM pointing covers about 70% of the INTEGRAL error circle (see Gotz et al., GCN 3430). The observations started at 00:18:21 UT (12.5 minutes after the trigger), and were performed in u', g' and r' simultaneously. The field was exposed for about 15 minutes, with a sampling time of one second, which is basically the same as the exposure time due to the negligible read-out time. Comparison of the individual exposures with the DSS-II reveals no obvious new source. Moreover, we looked for variability by combining all exposures (~1000) into 10 sets of 100 individual exposures each, and subtracting these off one other. Again, no obvious counterpart is detected. For more information on ULTRACAM, see: http://www.shef.ac.uk/physics/people/vdhillon/ultracam/ //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3434 SUBJECT: GRB 050520: Swift XRT position DATE: 05/05/20 10:44:37 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT J. A. Kennea, D. N. Burrows (PSU), M. Perri (ASDC), J. Cummings (GSFC) and N. Gehrels (NASA/GSFC) report on behalf of the Swift XRT team: INTEGRAL detected GRB050520 at 00:05:53 UT on 20th May 2005 (GCN Circ 3430). The Swift observatory executed an Target of Opportunity observation of the INTEGRAL position and the XRT began taking data at 02:13:34 UT. In a preliminary data analysis we detect a uncataloged X-ray source located at: RA(J2000) = 12:50:05.9, Dec(J2000) = +30:27:01 We estimate an uncertainty of 5 arcseconds radius (90% containment). This position is 49 arcseconds from the INTEGRAL position reported in GCN 3430. Observations are still underway and further ground analysis will be performed to determine if this X-ray source is fading. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3435 SUBJECT: GRB 050520: TAROT optical limit DATE: 05/05/20 11:37:42 GMT FROM: Jean-Luc Atteia at Lab d Astrophys.,OMP,Toulouse Klotz, A., Boer M. (OHP), and Atteia, J.L. (LAT) report: We imaged the entire field of GRB 050520 detected by INTEGRAL (cf. Gotz et al. GCNC 3430) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. Observations started at 00:06:40s UT, 8 seconds after the GCN notice, and 47s after the GRB. The field had an elevation of 46 degrees above horizon at the begining of the observations. The first two images (unfiltered) were recorded while the burst was still active. We detect no source at the position of the X-ray afterglow seen by SWIFT (Kennea et al. GCNC 3434), either during or after the burst. We measure the following magnitude limits: Image # start time end time Rlim #1 To+47s To+62s 16.0 #2 To+69s To+84s 16.0 #1+2 To+47s To+84s 16.1 #3-10 To+90s To+451s 17.2 This notice can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3437 SUBJECT: GRB050520: Liverpool Telescope follow-up DATE: 05/05/20 14:37:30 GMT FROM: Cristiano Guidorzi at ARI,Liverpool JMU C. Guidorzi, I. A. Steele, A. Monfardini, C.J. Mottram, A. Gomboc, D. Carter, M.F. Bode, C.G. Mundell, R.J. Smith (Liverpool JMU) report: "The 2-m Liverpool Telescope followed up robotically the INTEGRAL GRB050520 (Gotz et al, GCN 3430) and started observing 4.5 min after the GRB at 00:10:25.7 UT. The GRB pipeline did not detect any candidate r'<16.6 in the first 3 10-s images. In particular, no source has been found in the XRT error circle (Kennea et al., GCN 3434). From a 3x120s stacked image taken between 8 min and 16 min after the GRB, we detect no candidate r'<20. Limiting magnitudes have been derived by comparison with USNOB1. These poor limits are mainly due to the proximity of the Moon. This message can be cited." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3438 SUBJECT: GRB 050520: P200 Observations DATE: 05/05/20 14:59:28 GMT FROM: S. Bradley Cenko at Caltech S. Bradley Cenko, Derek B. Fox, S. R. Kulkarni, Naveen Reddy, Dawn Erb, David Law, and Chuck Steidel report on behalf of the Caltech-NRAO-Carnegie GRB collaboration: We have imaged the field of GRB 050520 (Gotz et al., GCN 3430) with the Wide Field Infrared Camera (WIRC) mounted on the Palomar 200" Hale Telescope. Observations consisted of 27 dithered frames for a total integration time of 22.5 minutes at a mean epoch of approximately 6:35 UT (6.5 hours after the burst). All images were taken in the Ks filter. We find no sources inside the XRT error circle (Kennea et al, GCN 3434). Our limiting magnitude, estimated by comparison with the 2mass object 12501123+3027515 (Ks = 15.42), is approximately Ks > 20.0. However, we do find two faint sources just outside the XRT error circle. Their coordinates (J2000.0) and approximate magnitudes are: RA Dec Distance from XRT Ks ------------------------------------------------------------------------- 12:50:06.0 30:27:06.7 5.8" 19.3 12:50:06.3 30:26:55.1 7.8" 19.1 Both sources are too faint to search for variability in our exposures. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3439 SUBJECT: RBO Observations of GRB050520 DATE: 05/05/20 15:22:22 GMT FROM: Ron Canterna at U of Wyoming D. Allen, C. Rodgers and R. Canterna report on behalf of the RBO Team of the FUN GRB Collaboration: We observed the position of the afterglow of GRB 050520 (Gotz et al., GCN 3430; Kennea et al., GCN 3434) with the Red Buttes Obse rvatory 24-inch telescope under semi-photometric conditions in VRI bands, all 10 minutes exposures on JD2453510.6. Within a FOV of 8 arcmin of the Swift position (GCN 3434) we do not detect the afterglow or no new source down to the following limiting values: UT Start Time Filter Limiting Since GRB (hr) Magnitude 03:39 3:34 V 19.5 03:51 3:45 R 19.5 04:01 3:55 I 18.3 04:12 4:06 V 19.4 04:23 4:17 R 19.7 04:34 4:28 I 18.4 04:46 4:40 V 19.6 04:56 4:50 R 19.4 05:07 5:11 I 19.0 05:19 5:13 V 19.6 05:29 5:23 R 19.8 05:40 5:44 I 18.8 10 sigma limiting magnitudes were derived from the USNO-B1.0 catalogue and photometric transformations from Landolt standards. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3443 SUBJECT: GRB 050520: Swift XRT refined analysis DATE: 05/05/20 20:40:49 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT M. Perri, M. Capalbi, P. Giommi (ASDC), J. A. Kennea, D. N. Burrows (PSU), J. Norris, N. Gehrels (GSFC) report on behalf of the Swift XRT team: We have analyzed the Swift XRT data from the GRB 050520 discovered by INTEGRAL (Gotz et al., GCN 3430). The source identified by Kennea et al. 2005 (GCN 3434) is clearly fading and is therefore the likely X-ray afterglow of this burst. The new refined coordinates of the X-ray afterglow are: RA(J2000) = 12:50:06.2 Dec(J2000) = 30:27:02 This position is 53 arcseconds from the INTEGRAL position given in GCN 3430 (Gotz al. 2005) and 4 arcsec from the preliminary XRT position reported in GCN 3434 (Kennea et al. 2005). We estimate an uncertainty of 5 arcseconds radius (90% containment). The first and second sources reported in GCN 3438 (Cenko et al. 2005) are 5.4 and 7 arcseconds from the center of our refined error circle, respectively. The total exposure time in Photon Counting (PC) mode is 16860 seconds starting from 02:13:39 UT to 14:52:09 UT on 20 May 2005. The 0.3-10 keV light curve can be fitted by a single power law with decay index alpha = -1.4 +/- 0.6. The average source count rate (0.5-10 keV) is (2.8+/-0.5)e-3 cts/s. Assuming a Crab-like spectrum and Galactic absorption (1.2e20 cm^-2) the average estimated unabsorbed 0.5-10 keV flux is 1.0e-13 erg cm^-2 s^-1. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3444 SUBJECT: Swift UVOT Observations of GRB 050520 DATE: 05/05/20 21:04:44 GMT FROM: Caryl Gronwall at PSU/Swift-UVOT C. Gronwall (PSU), J. Norris (GSFC), A. Morgan (PSU), P. Schady (MSSL), N. Gehrels (GSFC), on behalf of the Swift UVOT Team INTEGRAL detected GRB 050520 at 00:05:53 UT on 20th May 2005 (Gotz et al., GCN 3430). Swift executed a Target of Opportunity observation of the INTEGRAL position. The Swift Ultra-Violet/Optical Telescope (UVOT) began observations of GRB050520 at UT 02:13:38, approximately 2hr 8 minutes after the INTEGRAL detection. We detect no new source within the Swift XRT error circle (Kennea et al., GCN Circ. 3443) in any of the UVOT filters with the following 5 sigma and 3 sigma limits (in 6" radius apertures): Filter Lim_Mag Lim_mag Total duration (s) T_range (hr) 5sigma 3sigma V 19.84 20.39 3069 5.48 - 13.26 B 21.05 21.60 2699 4.98 - 11.90 U 20.58 21.13 2674 3.62 - 11.65 UVW1 21.30 21.86 3173 3.37 - 13.73 UVM2 21.36 21.91 2824 2.13 - 13.50 UVW2 21.64 22.19 2456 5.23 - 12.12 T_range is time since the INTEGRAL detection. The magnitudes are based on preliminary zero-points, measured in orbit, and will require refinement with further calibration. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3445 SUBJECT: GRB 050520: VLT/ULTRACAM observations DATE: 05/05/21 01:26:29 GMT FROM: Paul Vreeswijk at ESO P. Vreeswijk (ESO), T. Marsh (U. Warwick), S. Littlefair, V. Dhillon (U. Sheffield), K. O'Brien (ESO) report on behalf of a larger collaboration: The Swift XRT afterglow (see Kennea et al., GCN 3434, Perri et al., GCN 3443) is located roughly 15" off the field-of-view of the VLT/ULTRACAM observations reported in GCN 3433. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3453 SUBJECT: GRB050520: Radio Observations DATE: 05/05/22 20:08:32 GMT FROM: Patrick B. Cameron at Caltech P. B. Cameron (Caltech) and A. M. Soderberg (Caltech) report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration: "We observed the field of GRB050520 (GCN#3430) using the Very Large Array at a frequency of 8.46 GHz on May 20.43 UT and May 21.43 UT. We do not detect a radio source within the refined XRT error circle (GCN#3443). We place a 2-sigma upper limit of 57.6 uJy." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3458 SUBJECT: GRB050520,optical observation DATE: 05/05/23 09:48:27 GMT FROM: Shouta Maeno at U.of Miyazaki S.maeno,E.sonoda,Y.Tokunaga,M.Yamauchi (University of Miyazaki) "We have observed the field covering the error circle of GRB 050520 (GCN3430 ; INTEGRAL Trigger time is 00:05:53 UT) with the unfiltered CCD camera on the 30-cm telescope at University of Miyazaki. The observation was started 11:53:37 UT on May.20. Observed field of view is 43 arcmin centered on R.A=+12:50:50.9 Dec=+30:22:09.5 After co-adding a set of 5 images (11:53:37 - 11:58:08 UT) of 30 sec exposures, we have compared with the USNO A2.0 catalog. Preliminary analysis shows there is no new source brighter than 17.2 mag.