//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14586 SUBJECT: GRB 130505B: MAXI/GSC detection DATE: 13/05/06 09:23:09 GMT FROM: Motoko Suzuki at RIKEN M. Serino (RIKEN), H. Negoro (Nihon U.), S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa (JAXA), T. Mihara, M. Sugizaki, M. Morii, T. Yamamoto, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), N. Kawai, R. Usui, K. Ishikawa, T. Yoshii (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Nakano, Y. Kawakubo (AGU), H. Tsunemi, M. Sasaki (Osaka U.), M. Nakajima, T. Onodera, K. Fukushima, K. Suzuki (Nihon U.), Y. Ueda, M. Shidatsu, T. Kawamuro (Kyoto U.), Y. Tsuboi, M. Higa (Chuo U.), M. Yamauchi, K. Yoshidome, Y. Ogawa, H. Yamada (Miyazaki U.), K. Yamaoka (Nagoya U.) report on behalf of the MAXI team At 2013-05-05T23:54 UT, the MAXI/GSC detected an uncatalogued X-ray transient source. Assuming a constant source flux over the scan transit, we obtain the source position at (R.A., Dec.) = (139.500 deg 1.500 deg) = (09 18 00, +01 30 00)(J2000) with a 90% C.L. statistical error of 0.3 deg and an additional systematic uncertainty of 0.1 deg (90% containment radius). The averaged X-ray flux was 160 +/- 40 mCrab (4-10 keV). There were no significant excess fluxes at the previous and followed scan transits at 2013/05/05 22:20 UT and 2013/05/06 01:26 UT, respectively, with an upper limit of 20 mCrab for each. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14594 SUBJECT: GRB 130505B: Swift Candidate Afterglow DATE: 13/05/06 23:15:51 GMT FROM: Frank Marshall at GSFC D. Kocevski (NASA/GSFC/ORAU), F. E. Marshall (NASA/GSFC), M. De Pasquale (MSSL-UCL), P. D'Avanzo (INAF-OAB), and A. Melandri (INAF-OAB) report on behalf of the Swift team: The Swift began tiling observations of the field of GRB 130505B 16 hours after the MAXI trigger (Serino et al., GCN Circ. 14586). A bright source not in the DSS is seen in the UVOT observation at a preliminary position of RA(J2000) = 09:17:22.18 = 139.34124 DEC(J2000) = +01:42:03.1 = +1.70085 with a 90%-confidence error radius of about 0.6 arc sec. It is not possible to determine whether the source is varying with the currently available data. The position is consistent with that of SDSS J091721.89+014203.2, but more than 5 magnitudes brighter in the u band. The SDSS source could be the host galaxy for the burst, or could indicate that the MAXI source is a galactic transient. The preliminary detection using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the exposure is: Filter T_start(s) T_stop(s) Exp(s) Mag u 58617 59042 425 18.0 +/- 0.1 The magnitude is not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.024 in the direction of the burst (Schlegel et al. 1998). We have also analysed 426 s of Swift-XRT data from 58.6 ks to 59.0 ks after the MAXI trigger. The data are all in Photon Counting (PC) mode. A preliminary analysis reveals the presence of a source at the following position RA, Dec = 139.34180, +1.70215 which is equivalent to: RA (J2000): 09 17 22.03 Dec(J2000): +01 42 07.7 with an uncertainty of 4.5 arcsec (radius, 90% confidence). This position is consistent with the UVOT one. The observed count rate is (3.0 +/- 1.0) x 10^-2 cts/s. Given the low significance of the detection, at the present stage, it is not possible to determine whether the source is variable. Automated analysis of the XRT data can be found online at http://www.swift.ac.uk/xrt_products/TILED_GRB00015/ Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; and 2009, MNRAS, 397, 1177). Additional observations with Swift are scheduled. Observations with other observatories of this interesting object are encouraged. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14604 SUBJECT: GRB 130505B: Further Swift observations DATE: 13/05/08 15:39:28 GMT FROM: Andrea Melandri at INAF-OAB A. Melandri, P. D'Avanzo, (INAF-OAB), M. De Pasquale, S. Oates (MSSL/ UCL), D. Kocevski (NASA/GSFC/ORAU), F. E. Marshall (NASA/GSFC), P. A. Evans (U. Leicester) on behalf of the Swift team The optical source identified by Swift/UVOT in the field of MAXI GRB130505B (Kocevski et al., GCN circ. 14594) and coincident with SDSS J091721.89+014203.2 has dimmed by more than 3 magnitudes between 58.6 and 86.7 ks after the trigger (Serino et al., GCN circ. 14586), and it is not detected in the last exposure, centered at 153.9 ks, down to a 3 sigma upper limit of u=22.1. This source is seen to be fading also by Swift/XRT between 58.6 and 163.0 ks with a decay index ~2.6. The spectrum can be fitted with an absorbed power-law with a spectral photon index of 2.19 (+2.09, -0.79). The best fitting absorption column is 1.6 (+4.1, -1.6) × 10^21 cm-2, consistent with the Galactic value of 2.4 x 10^20 cm-2 (Kalberla et al. 2005). Assuming this spectrum, the last XRT detection correspond to a 0.3-10 keV flux of (4.5 ± 2.2) x 10^-14 erg cm-2 s-1. The very fast optical decay is unprecedented in GRB afterglows, and we cannot exclude a Galactic transient nature for this transient.