//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9572 SUBJECT: GRB 090625B: a long GRB localized by INTEGRAL DATE: 09/06/25 14:18:54 GMT FROM: Sandro Mereghetti at IASF/CNR D.Gotz (CEA-Saclay), S.Mereghetti, A.Paizis (IASF-Milano), A. Neronov, V.Beckmann, M. Beck (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: A long GRB with duration of about 11 s has been detected by IBAS in IBIS/ISGRI data at 13:26:21 UT on June 25th. The refined coordinates (J2000) are: RA: 2.2626 [degrees] DEC: -65.7816 [degrees] with an uncertainty of 1.7 arcmin (90% c.l.). A preliminary analysis gives a peak flux in the 20-200 keV range of about 2 ph/cmq/s (1 s integration time) and a fluence over the same energy range of about 1.5e-6 erg/cmq. A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9573 SUBJECT: GRB 090625B: Swift observation of the INTEGRAL GRB 090625B DATE: 09/06/25 14:50:41 GMT FROM: David Burrows at PSU/Swift J. Mao (INAF-OAB), D. N. Burrows (PSU), E. A. Hoversten (PSU), J. A. Kennea (PSU), K. L. Page (U Leicester), M. A. Stark (PSU) and R. L. C. Starling (U Leicester) report on behalf of the Swift Team: Swift executed a Target of Opportunity observation of the INTEGRAL GRB 090625B, slewing to the burst at 14:24 UT. XRT observations began at 14:30:13. The observation begins too late after the burst for us to determine whether any sources in the field of view are fading. However, we find a faint X-ray source located at RA,Dec = 2.2618, -65.7803 which is equivalent to: RA (J2000.0) = 00 09 2.83 DEC (J2000.0) = -65 46 49.2 with an uncertainty of 4.1 arcsec (radius, 90% containment). UVOT observations are being made, but data will not be available until a ground downlink. Burst Advocate for this burst is J. Mao (jirong.mao AT brera.inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9574 SUBJECT: GRB 090625B: Faulkes Telescope South observations DATE: 09/06/25 17:20:34 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy C. Guidorzi (U. Ferrara), D. Bersier (Liverpool JMU), P. O'Brien, N. Tanvir (U. Leicester) on behalf of a large collaboration report: On 2009 June 25 at 13:28:21 UT the 2-m Faulkes Telescope South automatically began observing the INTEGRAL GRB 090625B (Gotz et al., GCN Circ. 9572). Observations started 120 seconds after the IBAS trigger time and were performed using the B, V, R and i' filters. We could not find any uncatalogued object inside the XRT error circle (Mao et al., GCN Circ. 9573) down to the following limiting magnitudes: For single frames: Mid Time Exposure Filter Limit (s) (s) (mag) ------------------------------------- 141 3x10 R > 19.3 526 10 i' > 18.5 ------------------------------------- For coadded frames: Time Range Exposure Filter Limit (min) (s) (mag) ------------------------------------- 22.5-45.2 420 R > 21.0 25.4-48.2 420 i' > 20.3 ------------------------------------- Calibration was performed using a few USNOB1 nearby stars, adopting R2 and I values. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9578 SUBJECT: GRB 090625B: GROND upper limits DATE: 09/06/26 09:29:18 GMT FROM: Thomas Kruehler at MPE/MPI T. Kruehler, F. Olivares, and J. Greiner (all MPE Garching) report on behalf of the GROND team: We observed the field of GRB 090625B (Gotz et al., GCN #9572) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPI/ESO telescope at La Silla Observatory (Chile). Observations started on 26 June 2009 at 03:58 UT, 14.5 hours after the burst, continued until 05:58 UT and were performed under variable sky conditions. In stacked images of 75 min total integration time in griz and 60 min in JHK, we do not detect any object within the XRT error circle (Mao et al., GCN #9573), down to the following limiting magnitudes (all in the AB system): g' > 23.6 r' > 23.8 i' > 23.1 z' > 22.7 J > 21.5 H > 21.0 K > 20.5 These upper limits were derived using USNO-B1 and 2MASS field stars as reference. No correction has been made for the Galactic foreground extinction corresponding to E(B-V) of 0.02 mag (Schlegel et al., 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9580 SUBJECT: GRB 090625B: Swift-XRT refined analysis DATE: 09/06/26 11:44:10 GMT FROM: Jirong Mao at INAF-OAB J. Mao, R. Margutti (INAF-OAB) and C. Guidorzi (U. Ferrara) report on behalf of the Swift-XRT team: We have analyzed the first three orbit data (6.9 ks exposure) of the Swift ToO observation of the INTEGRAL burst GRB 090625B (Gotz, GCN Circ. 9572). Swift-XRT observations started at 14:30:13 UT (Mao et al. GCN Circ. 9573), 4ks from trigger. The source is fading with a best fit simple power law model index of alpha= 0.6+/- 0.3, confirming its nature of X-ray afterglow. A spectrum extracted from PC mode data can be modelled with an absorbed power-law, with Gamma = 3.3 +1.1/-0.8 and NH = (3.7 +2.2/-1.7)x1021 cm^-2. The Galactic column in this direction is 2.1 x 1020 cm-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.8 x 10-11 (1.8 x 10-10) erg cm-2 count-1. If the light curve continues to decay with a power-law decay index of 0.6, the count rate at T+24 hours will be 6.3x10-3 count s-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.8x10-13 (1.1x10-12) erg cm-2 s-1. This circular is an official product of the Swift-XRT team. [GCN OPS NOTE(26jun09): Per author's request, "Cristiano" was replaced with "Guidorzi".] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9581 SUBJECT: GRB 090625B: Swift/UVOT Upper Limits DATE: 09/06/26 16:56:21 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/GSFC/USRA) and J. Mao (INAF-OAB) report on the behalf of the Swift UVOT team: The Swift/UVOT observed the field of GRB 090625B starting 3679 s after the INTEGRAL/IBAS detection (Gotz, et al., 2009, GCN Circ. 9572). We do not find any new source, relative to the DSS, USNO-B1.0, or 2MASS at the position of the XRT afterglow (Mao, et al. 2009, GCN Circ. 9573). Preliminary 3-sigma upper limits for detecting a source in the co-added images are Filter T_start T_stop Exp(s) Mag -------------------------------------------- v 3679 5007 318 >20.0 b 4192 11,398 413 >20.8 u 3987 67,218 6439 >21.7 uvw1 5218 17,045 1781 >21.5 uvm2 5012 16,139 1082 >21.0 uvw2 4602 4802 197 >20.1 white 3828 4596 344 >21.8 -------------------------------------------- The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E_{B-V} = 0.02 mag (Schlegel, et al., 1998, ApJS, 500, 525). All photometry is on the UVOT photometry system described in Poole et al. (2008, MNRAS, 383, 627). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9583 SUBJECT: GRB 090625B: Fermi GBM observation DATE: 09/06/26 21:49:03 GMT FROM: Arne Rau at MPE Arne Rau (MPE) reports on behalf of the Fermi GBM Team: "At 13:26:22.51 UT on 25 June 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090625B (trigger 267629184 / 090625560) which was also detected by the INTEGRAL (Goetz et al. 2009, GCN 9572). The GBM on-ground location is consistent with the INTEGRAL position. The angle from the Fermi LAT boresight is 125 degrees. The GBM light curve consists of a single pulse with a duration (T90) of about 13.6 s (8-1000 keV). The time-averaged spectrum from T0-2.048 s to T0+6.144 s is well fit by a power law function with an exponential high energy cutoff. The power law index is -0.9 +/- 0.2 and the cutoff energy, parameterized as Epeak, is 165 +/- 28 keV (chi squared 429 for 453 d.o.f.). The event fluence (8-1000 keV) in this time interval is (1.04 +/- 0.13)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+3.072 s in the 8-1000 keV band is 1.87 +/- 0.09 ph/s/cm^2. A Band function fits the spectrum equally well (chi squared 424 for 454 d.o.f.) with Epeak= 100 +/- 32 keV, alpha = -0.4 +/- 0.5, and beta -2.0 +/- 0.2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."