//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16981 SUBJECT: GRB 141029A: MAXI/GSC detection DATE: 14/10/29 06:00:25 GMT FROM: Motoko Suzuki at RIKEN S. Nakahira (JAXA), H. Negoro (Nihon U.), S. Ueno, H. Tomida, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Morii, M. Serino, J. Sugimoto, T. Takagi, A. Yoshikawa, M. Matsuoka (RIKEN), N. Kawai, T. Yoshii, Y. Tachibana (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, D. Uchida (Osaka U.), M. Nakajima, K. Fukushima, T. Onodera, K. Suzuki, T. Namba, M. Fujita, F. Honda (Nihon U.), Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.), Y. Tsuboi, A. Kawagoe (Chuo U.), M. Yamauchi, Y. Morooka, D. Itoh (Miyazaki U.), K. Yamaoka (Nagoya U.) report on behalf of the MAXI team: The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 04:32:09 UT . Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (69.413 deg, -16.481 deg) = (04 37 39, -16 28 51) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.28 deg and 0.23 deg respectively. The roll angle of long axis from the north direction is 170.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 137 +- 24 mCrab (4-10keV, 1 sigma error). There was no significant excess flux in the previous transit at 02:59 UT. with an upper limit of 20 mCrab. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16984 SUBJECT: GRB 141029A Tiled Swift observations DATE: 14/10/29 08:58:18 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a series of observations, tiled on the sky, of the MAXI GRB 141029A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00031 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the MAXI event is high: any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; and 2009, MNRAS, 397, 1177). This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16994 SUBJECT: GRB 141029A: Nanshan optical upper limit DATE: 14/10/30 19:08:31 GMT FROM: Dong Xu at DARK/NBI D. Xu (DARK/NBI), G.-J. Feng, X. Zhang, A. Esamdin, L. Ma (XAO) report: We observed the field of the three X-ray afterglow candidates (see http://www.swift.ac.uk/xrt_products/TILED_GRB00031/) of GRB 141029A detected by MAXI/GSC (Nakahira et al., GCN16981), using the 1m telescope located at Nanshan, Xinjiang, China. We obtained 2x300s and 1x600s R-band images, starting at 19:37 UT on 2014-10-29 (i.e., 15.09 hr after the trigger). As reported, the X-ray source 1 (S1) and source 2 (S2) have catalogued optical counterparts already, and the X-ray source 3 (S3) located at R.A. = 04:37:20.17, Dec. = -16:08:09.3 (with Error Radius=8.8′′) doesn't have a catalogued optical counterpart. However, no optical source is detected at the S3 position in the Nanshan images, down to a limiting magnitude of R=20.5 mag. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17016 SUBJECT: MAXI GRB 141029A is likely an X-ray flare from 1RXS J043657.1-161258 DATE: 14/11/01 10:09:44 GMT FROM: Satoshi Nakahira at JAXA/MAXI S. Nakahira (JAXA), N. Kawai (Tokyo Tech), T. Sakamoto (AGU), K. Yamaoka (Nagoya U),$B!!(B H. Negoro (Nihon U.), M. Serino (RIKEN), P. A. Evans (U. Leicester), K. L. Page (U Leicester) on behalf of the MAXI team and the Swift-MAXI collaboration The Swift ToO observation of GRB141029A (Nakahira et al., GCN16981) was performed starting from 2014-10-29T09:00:37 with 4-point tiling to cover the MAXI error circle. We found three X-ray sources in the MAXI error circle as shown in the Swift observation summary page http://www.swift.ac.uk/xrt_products/TILED_GRB00031/. One of the sources ("source 1") showed suggestive fading between the two tilings centered at 15500 s and 20700 s after the MAXI detection with count rates of 2.7 +- 0.3 c/s and 1.7 +- 0.2 c/s respectively. Assuming a power-law spectrum with photon index of 2.4 the X-ray flux at the first Swift pointing is estimated as 6.8 x 10^-11 erg/cm2/s, two order of magnitude fainter than 5.6 x 10^-9 erg/cm2/s at the MAXI detection. The fading behavior was confirmed by additional Swift TOO observation conducted from 2014-10-30T10:14:59 with a detected count rate of 0.27+-0.02 c/s. This fading source matches a catalogued X-ray source 1RXS J043657.1-161258, whose position in the ROSAT All-Sky Survey Bright Source Catalog is 9.1" away from the Swift position with a 3-sigma positional error of 40.1". The source flux in the catalog corresponds to 9.3 x 10^-12 erg/s/cm2, indicating that the fluxes in the present Swift observations were in much elevated states. The source was also reported to be variable (Fuhrmeister and Schmitt 2003). Thus, we conclude that 1RXS J043657.1-161258 is the most likely source of the MAXI transient. This optical counterpart of 1RXS J043657.1-161258 has been studied, and found to be variable with with possible rotational period of P=0.3787d or P =2.74d (Kiraga et al. 2012). These characteristics of the source suggest that the X-ray transient observed by MAXI was a strong flare from an active star system such as RS CVn star, dMe star, or a cataclysmic variable. Non-detection of an optical counterpart of source 3 reported by Xu et al. ( GCN16994) further supports that this transient was not a gamma-ray burst. We thank the Swift team for performing the observation.