//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8786 SUBJECT: GRB 090107B: a long GRB localized by INTEGRAL DATE: 09/01/07 17:05:19 GMT FROM: Diego Gotz at CEA D. Gotz (CEA-Saclay), S.Mereghetti, A.Paizis (IASF-Milano), C. Ferrigno, V.Beckmann, M. Beck (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: A GRB lasting about 20 s has been detected by IBAS in IBIS/ISGRI data at 16:20:36 UT on January 7th. The refined coordinates (J2000) are: RA = 284.8075 [degrees] DEC= 59.5924 [degrees] with an uncertainty of 1.5 arcmin (90% c.l.). A preliminary analysis gives a peak flux in the 20-200 keV range of about 1.6 ph/cmsq/s (1-s integration time) and a fluence over the same energy range of about 1.5e-6 erg/cmsq. Both values have to be considered lower limits, since the burst is affected by telemetry saturation. 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: 8787 SUBJECT: GRB 090107B: ROTSE-III Optical Limits DATE: 09/01/07 17:48:17 GMT FROM: Tolga Guver at UA GRB 090107B: ROTSE-III Optical Limits T. Guver (U Arizona), H. Swan (U Mich), report on behalf of the ROTSE collaboration: ROTSE-IIId, located at the TUBITAK National Observatory at Bakirlitepe, Turkey, responded to GRB 090107B (INTEGRAL trigger 5398; D. Gotz, GCN 8786), producing images beginning 0.0 s after the GCN notice time. An automated response took the first image at 16:20:40.7 UT, 4.7 s after the burst, and during the gamma-ray emission, under fair conditions. We took 10 5-sec, 10 20-sec and 63 60-sec exposures. These unfiltered images are calibrated relative to USNO A2.0 (R). Imaging is on going. Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma INTEGRAL/IBIS error circle, for both single images and coadding into sets of 10. Individual images have limiting magnitudes ranging from 16.2-16.6; we set the following specific limits. start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd? -------------------------------------------------------------------- 16:26:35.8 16:26:55.8 20 16.6 359.8 N 16:28:03.0 16:32:41.6 278 17.7 447.0 Y //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8788 SUBJECT: GRB 090107B optical observations DATE: 09/01/07 17:53:05 GMT FROM: Arne A. Henden at AAVSO Arto Oksanen (Hankasalmi Obs., Hankasalmi, Finland) reports via the AAVSO High Energy Network the following optical observations of the INTEGRAL burst GRB 090107B (Gotz et al., GCN Circular #8786): Unfiltered observations were made using a 0.4-meter RC telescope with an SBIG STL-1001E CCD. The full INTEGRAL error box was observed unfiltered starting at 16:35UT, 15 minutes after the burst. Combining ten 60-second exposures, we do not see any optical afterglow to a limiting magnitude of 20.5 (compared with the DSS2 red plate). A FITS image of this observation is available at the following URL: ftp://ftp.aavso.org/grb/ArtoOksanen_GRB090107_2454839.23238_.fits The AAVSO thanks the Curry Foundation for their continued support of the AAVSO International High Energy Network. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8789 SUBJECT: GRB 090107B: Swift-XRT detection of possible afterglow DATE: 09/01/07 21:09:39 GMT FROM: Matteo Perri at ISAC/ASDC M. Perri (ASDC) and P. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift began observing the field of the INTEGRAL GRB 090107B (Gotz et al., GCN Circ. 8786) 4.2 ks after the trigger. A single uncatalogued source was identified within the IBIS/ISGRI error circle. Using 1314 s of XRT Photon Counting mode data and 2 UVOT images, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 284.81750, 59.59510 which is equivalent to: RA (J2000): 18 59 16.21 Dec (J2000): +59 35 42.3 with an uncertainty of 1.8 arcsec (radius, 90% confidence). The source lies 21 arcsec from the IBIS/ISGRI centroid and has a count rate of ~0.25 counts/s during this observation. Currently we cannot determine if this source is fading, and therefore cannot confirm if this source is associated with GRB 090107B. Observations of this source are on-going. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8790 SUBJECT: GRB 090107B: Swift/UVOT Observations DATE: 09/01/07 21:41:56 GMT FROM: Frank Marshall at GSFC F.E. Marshall (NASA/GSFC) reports on behalf of the Swift/UVOT team: The Swift/UVOT observed the field of GRB 090107B starting 4396 s after the INTEGRAL trigger (Gotz et al., GCN Circ. 8786). No optical afterglow is detected in the initial UVOT exposures at the position of the candidate X-ray afterglow (Perri et al., GCN Circ. 8789). There is also no obvious optical afterglow candidate elsewhere in the INTEGRAL error circle. The 3-sigma upper limits in the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for detecting a source at the position of the XRT candidate are: Filter T_start(s) T_stop(s) Exp(s) Mag white 5420 5535 113 >20.9 v 4396 4595 197 >19.6 b 5216 5415 197 >20.3 u 5010 5209 197 >20.1 uvw1 4806 5005 197 >20.3 uvm2 4600 4799 197 >20.3 uvw2 4191 4390 197 >20.6 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.046 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8791 SUBJECT: GRB 090107B: Swift XRT afterglow confirmation DATE: 09/01/09 16:08:56 GMT FROM: Matteo Perri at ISAC/ASDC G. Stratta (ASDC), M. Perri (ASDC) and J. R. Cummings (GSFC/UMBC) report on behalf of the Swift-XRT team: The Swift ToO observations of GRB 090107B started on 2009 Jan 7th at 17:30:50 UT. XRT data set consists of 5.7 ks exposure in PC mode. The single, uncatalogued X-ray source observed in the field of INTEGRAL, previously reported by Perri et al. (GCN Circ. 8789), shows fading flux, confirming its afterglow nature. The 0.3-10 keV light curve from T + 4.2 ks to T + 96.4 ks possibly indicates evidence for a plateau phase followed by a steeper decay, but the available data prevented us from constraining the parameters (i.e. the temporal break and the two decay indexes). Assuming a simple power law model, the best fit decay index is alpha = 1.3 +/- 0.1. The average spectrum accumulated in the same time interval was fitted with an absorbed power law. The best fit photon index is 1.8 +/- 0.4. The spectrum shows evidence of absorption at the level of (9 +/- 1)e20 cm-2, in excess of the estimated Galactic value (5e20 cm-2, Kalberla et al. 2005). The average observed[unabsorbed] 0.3-10 keV average flux is about 2.8[3.6]e-12 ergs cm-2 s-1. The predicted count rate 48 hours after the trigger is 0.002 cts/s The count-rate-to-flux conversion factor is 5.2e-11 ergs cm-2 cts-1 All quoted errors are at 90% confidence level. Burst Advocate for this burst is J. R. Cummings. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8793 SUBJECT: GRB090107B: Fermi GBM Detection DATE: 09/01/09 23:33:40 GMT FROM: Adam Goldstein at Fermi-GBM/UAH A. Goldstein (UAH), R. Preece (UAH), and A.J. van der Horst (NASA/ORAU) report on behalf of the Fermi GBM Team: "At 16:20:42.77 UT on 07 January 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090107B (trigger 25303844 / 090107681). This burst was also detected by the INTEGRAL IBAS (D. Gotz et al. 2009, GCN 8786) The GBM on-ground location is consistent with the INTEGRAL position. The GBM light curve consists of two main emission peaks and apparent substructure with a duration (T90) of about 24.1 s (8-1000 keV). The time-averaged spectrum from T0-4.1 s to T0+20.5 s is best fit by a power law function with an exponential high energy cutoff. The power law index is -0.68 +/- 0.26 and the cutoff energy, parameterized as Epeak, is 106.1 +/- 14.8 keV (chi squared 530.4 for 486 d.o.f.). The event fluence (8-1000 keV) in this time interval is (1.75 +/- 0.37)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+6.1 s in the 8-1000 keV band is 3.68 +/- 0.27 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: 8794 SUBJECT: GRB 090107B: Suzaku WAM observation of the prompt emission DATE: 09/01/10 14:30:59 GMT FROM: Yujin E. Nakagawa at RIKEN Y. E. Nakagawa, T. Tamagawa (RIKEN), H. Hayashi, E. Sonoda, M. Yamauchi, H. Tanaka, R. Hara, N. Ohmori, K. Kono (Univ. of Miyazaki), A. Endo, M. Tashiro, Y. Terada, Y. Urata, K. Onda, N. Kodaka, K. Morigami, T. Sugasahara, W. Iwakiri (Saitama U.), T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), S. Sugita, K. Yamaoka (Aoyama Gakuin U.), M. Ohno, M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa, C. Kira (Hiroshima U.), S. Hong (Nihon U.), on behalf of the Suzaku WAM team, report: The long GRB 090107B (Gotz et al., GCN 8786) was detected by the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 2009-01-07 16:20:35 UT (=T0). The observed light curve shows a double-peaked structure lasting from T0-1 s to T0+20 s with a duration (T90) of about 14 seconds. The fluence in 100 - 1000 keV was 1.3 (+0.7, -0.9) * 10^-6 erg/cm^2. The 1-s peak flux measured from T0+13 s was 0.4 +/- 0.3 photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-1 s to T0+20 s is well fitted by a single power-law with a photon index of 2.0 +/- 0.4 (chi^2/d.o.f = 6/10). All the quoted errors are at statistical 90% confidence level, in which the systematic uncertainties are not included. The light curves with 1-sec time resolution for this burst will be appeared at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html