//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9815 SUBJECT: GRB 090817: a long GRB localized by INTEGRAL DATE: 09/08/17 02:53:44 GMT FROM: Volker Beckmann at ISDC V.Beckmann (ISDC, Versoix), D.Gotz (CEA-Saclay), S.Mereghetti, A.Paizis (IASF-Milano), A. Neronov, M. Beck (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: A long GRB with duration of about 250 s has been detected by IBAS in IBIS/ISGRI data at 00:51:33 UT on August 17th. The refined coordinates (J2000) are: RA: 63.9659 [degrees] DEC: +44.1234 [degrees] with an uncertainty of 2.6 arcmin (90% c.l.). The light curve shows two prominent peaks at T0 and at T0+196s. 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: 9819 SUBJECT: GRB 090817: Swift-XRT observations DATE: 09/08/17 13:59:42 GMT FROM: Kim Page at U.of Leicester P.A. Evans (U. Leicester), C. Guidorzi (U Ferrara) and W.H. Baumgartner (GSFC/UMBC) report on behalf of the Swift-XRT team: The Swift-XRT observed the field of GRB 090817 (Beckmann et al. GCN Circ. 9815) from T0+11 ks to T0+17.5 ks gathering 1.8 ks of Photon Counting (PC) mode data. Inside the INTEGRAL error circle we find a single, uncatalogued X-ray source at RA, Dec = 63.96600, 44.12900 which is equivalent to: RA (J2000): 04 15 51.85 Dec (J2000): +44 07 44.5 with an uncertainty of 2.0 arcsec (radius, 90% confidence). The optical source USNO-B1.0 1341-0096763 lies only 1.3 arcsec from the XRT position. This object is point-like in USNO-B1, with magnitudes I=18.5, R=20.0, B=20.8. The light curve of the X-ray source shows a rapid rise from 0.04 ct/sec at T0+11 ks to 0.1 ct s^-1 at T0+12 ks; by T0+18 ks the count rate has returned to 0.04 ct s^-1. A spectrum formed from the PC mode data can be modelled with an absorbed power law with a photon index of 2.5 (+0.7, -0.6) with an absorption column of 9.5 (+4.9, -4.0) x 10^21 cm^-2, in excess of the Galactic value of 4.0 x 10^21 cm^-2 (Kalberla et al. 2005). Given the light curve of this source, it is not clear whether or not this is a GRB afterglow. A further observation has therefore been planned, and will take place today. No other sources are detected in the INTEGRAL error circle, with a 3-sigma upper limit of 5 x 10^-3 ct s^-1. Using the typical counts-to-observed-flux conversion factor from Evans et al (2009, MNRAS, 397, 1177) this gives a flux limit of 1.7 x 10^-13 erg cm^-2 s^1. This circular is an official product of the Swift-XRT team. -- ------------------------- Phil Evans, Swift Development Scientist X-ray and Observational Astronomy Group, University of Leicester Tel: (0116) 252 5059 pae9@star.le.ac.uk http://www.star.le.ac.uk/~pae9 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9822 SUBJECT: GRB 090817: Swift/UVOT Upper Limits DATE: 09/08/17 15:58:28 GMT FROM: Alice Breeveld at MSSL-UCL A. Breeveld (MSSL/UCL) and W. Baumgartner (GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 090817 11008 s after the INTEGRAL trigger (Beckmann et al., GCN Circ. 9815). No new sources are found in the UVOT data at the position of the XRT source (P.A. Evans et al., GCN Circ. 9819). Preliminary 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) and a 3 arcsec radius aperture, for the initial summed exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 11516 17719 413 >21.3 v 11975 12398 416 >19.6 b 11058 17509 787 >21.2 u 11008 17157 78 >19.5 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.66 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9823 SUBJECT: GRB 090817: Fermi GBM observation DATE: 09/08/17 18:23:30 GMT FROM: Colleen A. Wilson at NASA/MSFC/NSSTC Colleen A. Wilson-Hodge (NASA/MSFC) reports on behalf of the Fermi GBM Team: "At 00:51:26.21 UT on 17 August 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090817 (trigger 272163088 / 090817036). which was also detected by INTEGRAL (Beckmann et al. 2009, GCN 9815) The GBM on-ground location is consistent with the INTEGRAL position. The angle from the Fermi LAT boresight is 82 degrees. The GBM light curve consists of an initial bright peak at the trigger time followed by a weak broad bump about 200 s after the trigger. This burst has a duration (T90) of about 220 s (8-1000 keV). Spectral analysis was performed only for the bright initial peak. The time-averaged spectrum from T0 to T0+41 s is adequately fit by a Band function with Epeak = 115 +/- 50 keV, alpha = -1.1 +/- 0.3, and beta = -2.2 +/- 0.6 The event fluence (8-1000 keV) over the T90 interval is (7.3 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.15 s in the 8-1000 keV band is 3.8 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9825 SUBJECT: GRB 090817: Confirmation of the X-ray afterglow DATE: 09/08/18 08:52:01 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester), C. Guidorzi (U Ferrara) and W.H. Baumgartner (GSFC/UMBC) report on behalf of the Swift-XRT team: Swift conducted a second observation of GRB 090817 (Beckmann et al. GCN Circ. 9815), collecting 3.9 ks of Photon Counting (PC) mode XRT data in the interval T0+50 ks to T0+58 ks. The source reported by Evans et al. (GCN Circ. 9819) has faded to a level of ~0.015 ct s^-1. A power-law fit to the light curve yields a temporal decay index of alpha=0.9+/-0.2 Inspecting the USNO-B1 catalogue within 3.5' of the GRB we find 216 objects with R2<20.0. The probability of finding a USNO-B1 source within a 2" radius circle in this field is thus 2%. The strength of the potential association between the XRT and USNO-B1 sources noted in GCN Circ. 9819 is therefore fairly weak. We therefore suggest that the XRT source is the afterglow of GRB 090817. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020108. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9826 SUBJECT: GRB 090817: optical upper limit DATE: 09/08/18 12:02:36 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Rumyantsev (CrAO), A. Pozanenko (IKI), M. Andreev (Terskol Branch of Institute of Astronomy) report on behalf of larger GRB follow-up collaboration: We observed a field of the INTEGRAL GRB 090817 (Beckmann et al., GCN 9815) with Shajn telescope of CrAO starting on Aug. 17 (UT) 01:07, i.e. ~17 minutes after burst onset. A series of 37 images of 60 s exposure was obtained in R filter. Within XRT error circle of the afterglow (Evans et al., GCN 9819, GCN 9825) we do not detect any new object. The quoted USNO-B1.0 star USNO-B1.0 1341-0096763 (Evans et al., GCN 9819) does not change its brightness within ~0.08 m during our observations. An upper limit of a single frame of 60 s exposure is R~21.5 m. Data reduction is continuing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9827 SUBJECT: GRB 090817: Liverpool Telescope Observations DATE: 09/08/18 18:56:21 GMT FROM: Zach Cano at ARI/John Moores Liverpool GRB 090817: Liverpool Telescope Observations Z. Cano, I.A. Steele, C.G. Mundell, A. Melandri, S. Kobayashi, C.J. Mottram, R.J. Smith, D. Bersier (Liverpool JMU), A. Gomboc (U. Ljubljana), report on behalf of a large collaboration: On August 17 2009, 1.459 hours after the burst was detected, the 2-m Liverpool Telescope automatically began observing the INTEGRAL GRB 090817 (Beckmann et al.,GCN Circ. 9815) using g',r' and i' filters. We do not detect any uncatalogued source inside the Swift-XRT error circle (Evans et al. GCN Circ 9819). Upper limits in stacked R and I images for isolated objects are 20.6 and 20.8 respectively. Magnitudes have been calibrated from the nearby USNO star (1341-0096766): 04:15:52.314, +44:07:50.9 using R2=17.56 and I=17.04. We note that the upper limits presented are the limits for detecting an isolated object in our images. As the USNO star (1341-0096763) lies only 1.3" from the XRT position the actual upper limits will be accordingly brighter. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9831 SUBJECT: GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate DATE: 09/08/20 19:17:42 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/GSFC/USRA), A. Breeveld (MSSL/UCL), and W. Baumgartner (GSFC/UMBC) report on behalf of the Swift UVOT team: The Swift/UVOT observed the field of GRB 090817 (Beckman et al., 2009, GCN Circ. 9815) between 11 ks and 284 ks after the INTEGRAL trigger. The USNO-B1.0 source 1341-0096763 (Evans et al. 2009, GCN Circ. 9819, Rumyantsev et al. 2009, GCN Circ. 9828) is detected inside the XRT error circle (Evans et al., 2009, GCN Circ. 9819). We find no evidence for variability in this source during our observations. Preliminary magnitudes and 3-sigma upper limits from all of the coadded data are Filter Exposure Mag Err Sigma -------------------------------------- v 416 19.86 0.46 2.4 b 787 20.99 0.33 3.4 u 4003 21.49 0.30 3.7 uvw1 4326 >22.0 ... ... white 413 21.19 0.37 3.2 The quoted magnitudes and upper limits have not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E_{B-V} = 0.66 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). The UVOT coordinates of this source are RA (J2000.0) 04:15:51.85 = 63.96604 (deg) Dec (J2000.0) +44:07:44.5 = +44.12902 (deg) with an estimated uncertainty of 1.0 arcsec (radius, 90% confidence, statistical + systematic). The dereddened colours of the source are not consistent with a stellar spectrum. However, the colours are consistent with an Sm or Im galaxy (de Vaucouleurs, 1961, ApJS, 5, 233). This suggests that the source may be the host galaxy of GRB 090817. If this galaxy has an absolute magnitude similar to that of the LMC then it is located at a redshift of approximately z = 0.05. An intrinsically fainter galaxy would be closer. Follow-up spectroscopy is encouraged to verify this. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9834 SUBJECT: GRB 090817: Swift/UVOT Observations of a Possible Late-Time Brightening DATE: 09/08/24 18:58:29 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/GSFC/USRA), A. Breeveld (MSSL/UCL), and W. Baumgartner (GSFC/UMBC) report on behalf of the Swift UVOT team: Swift/UVOT observed the USNO-B1.0 source 1341-0096763 (Evans et al. 2009, GCN Circ. 9819; Rumyantsev et al. 2009, GCN Circ. 9828; Holland et al. 2009, GCN Circ. 9831), which is located inside the XRT error circle (Evans et al., 2009, GCN Circ. 9819), at approximately 6 and 7 days after the INTEGRAL trigger (Beckman et al., 2009, GCN Circ. 9815). A preliminary examination of the UVOT data yields weak evidence that the source may have brightened by approximately 0.5 mag in the UVOT v band between approximately 6.5 and 7.1 days. Our observations are consistent with a supernova rising to maximum light. However, we stress that further observations are needed to confirm this. Follow-up photometric and spectroscopic observations of this source are strongly encouraged. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9837 SUBJECT: GRB 090817: No host galaxy, no supernova DATE: 09/08/25 11:16:13 GMT FROM: Jules Halpern at Columbia U. J. P. Halpern and J. Ruan (Columbia U.) report: We obtained R-band photometry of the USNO-B1.0 object 341-0096763 on 2009 August 21 10:46 UT using the McGraw Hill 1.3m telescope. In five 300 s exposures in seeing of 1.5"-1.8", there is no evidence to support the hypothesis of Holland et al. (GCN Circ. 9831) that this object is the host galaxy of GRB 090817. The image is consistent with the stellar point spread function. Using the reference star of Rumyantsev et al. (GCN Circ. 9828), we measure R = 19.39+/-0.04, consistent with their photometry on Aug. 17. On Aug. 25 09:56 UT, we again obtained five 300 s exposures in seeing of 1.5". We measure R = 19.42+/-0.03, 8.4 days after the burst, which is consistent with all previous measurements. Thus, there is no evidence for brightening suggested by Holland et al. (GCN Circ. 9834) from Swift UVOT observations between 6.5 and 7.1 days. The set of consistent magnitudes from day zero in GCN Circ. 9828 to days 4 and 8 in this report are indicative of a chance coincidence with a normal star. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9841 SUBJECT: GRB090817: Keck/LRIS Spectroscopy DATE: 09/08/26 08:22:47 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko, L. M. Walkowicz (UC Berkeley), M. M. Kasliwal, V. Bhalero, S. R. Kulkarni, F. A. Harrison (Caltech), I. Arcavi (Weizmann Institute) and W. H. Baumgartner (GSFC/UMBC) report on behalf of a larger collaboration: We have obtained a spectrum of the putative host galaxy of GRB09817 (Holland et al., GCNs 9831 and 9834) with the Low Resolution Imaging Spectrometer mounted on the 10 m Keck I telescope. Our spectra were taken in twilight conditions at Aug 25.55 UT and cover a wavelength range from 3500 - 9000 A. After correcting for the large Galactic extinction, the source exhibits a blue continuum with superposed absorption features from the H Balmer series (H-alpha, -beta, -gamma, and -delta) and Ca (H+K and the NIR triplet), all consistent with their rest wavelengths. As suggested by Halpern and Ruan (GCN 9837), the object is therefore a foreground star (likely a hot, ~ A-type) and likely unrelated to GRB090817. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9842 SUBJECT: GRB 090817 - TLS Observations DATE: 09/08/27 00:27:50 GMT FROM: Alexander Kann at TLS Tautenburg D. A. Kann, F. Cusano and F. Ludwig (TLS Tautenburg) report: We observed the field of the INTEGRAL/Fermi GRB 090817 (Beckmann et al., GCN 9815, Wilson-Hodge, GCN 9823) with the 1.34m Tautenburg Schmidt telescope under good conditions. We obtained 3 x 600 sec Rc images at a mid-time of 8.015 days after the GRB. At the position of the X-ray afterglow (Evans, Guidorzi & Baumgartner, GCN 9819, GCN 9825), the USNO-B1.0 object 1341-0096763 is clearly detected. Using the comparison star of Rumyantsev, Pozanenko & Andreev (GCN 9828), we find Rc = 19.54 +/- 0.03 mag. This is in agreement with the reports of non-variability (Rumyantsev, Pozanenko & Andreev, GCN 9828, Halpern & Ruan, GCN 9837) of this proposed host galaxy/SN candidate (Holland, Breeveld & Baumgartner, GCN 9831, GCN 9834), and a stellar PSF is in full agreement with it being a foreground star (Halpern & Ruan, GCN 9837, Cenko et al., GCN 9841). No further observations are planned. This message may be cited.