//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23389 SUBJECT: GRB 181030A: Swift detection of a burst with a possible optical counterpart DATE: 18/10/30 01:50:20 GMT FROM: David Palmer at LANL E. Sonbas (Adiyaman Univ.), J.D. Gropp (PSU), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), M. J. Moss (George Washington University), K. L. Page (U Leicester), M. H. Siegel (PSU) and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 01:27:22 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 181030A (trigger=869494). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 146.922, +14.658 which is RA(J2000) = 09h 47m 41s Dec(J2000) = +14d 39' 28" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual with an image trigger, the available BAT light curve shows no significant structure. The XRT began observing the field at 01:29:44.2 UT, 142.1 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 146.9251, 14.6582 which is equivalent to: RA(J2000) = 09h 47m 42.02s Dec(J2000) = +14d 39' 29.5" with an uncertainty of 4.8 arcseconds (radius, 90% containment). This location is 10 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 5.25e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 118 seconds with the White filter starting 151 seconds after the BAT trigger. There is a possible afterglow in the rapidly available 2.7'x2.7' sub-image near the position of the XRT afterglow. A precise position is unavailable due to a failed aspect correction. The estimated magnitude is 18.94 with a 1-sigma error of about 0.22. Burst Advocate for this burst is E. Sonbas (edasonbas AT yahoo.com). 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: 23390 SUBJECT: GRB 181030A: SAO RAS optical observations DATE: 18/10/30 03:51:54 GMT FROM: Moskvitin Alexander at SAO RAS A. S. Moskvitin and O. I. Spiridonova (SAO RAS) report on behalf of larger collaboration. We observed the field of GRB 181030A (Sonbas et al., GCNC #23389) with the Zeiss-1000 telescope of SAO RAS (+ CCD photometer) on the October, 30. The observations started since 10 minutes after the trigger (UT_start = 01:37:35, UT_end = 02:49:36). We obtained 12 x 300 sec. images in Rc band. We detect the OT discovered by the Swift/UVOT at the position (+/- 1"): R. A. (2000) = 09:47:42.3 Decl. (2000) = +14:39:25.8 The OT magnitude is R = 19.12 +/- 0.03 (UT_mid = 02:13:35). Calibrations were made against the nearby SDSS stars (magnitudes transformed to Rc according to the Lupton, 2005). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23391 SUBJECT: GRB 181030A: Enhanced Swift-XRT position DATE: 18/10/30 05:16:25 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 2439 s of XRT Photon Counting mode data and 6 UVOT images for GRB 181030A, 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 = 146.92603, +14.65731 which is equivalent to: RA (J2000): 09h 47m 42.25s Dec (J2000): +14d 39' 26.3" with an uncertainty of 1.7 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23392 SUBJECT: GRB 181030A: MASTER Net OT detection DATE: 18/10/30 06:57:40 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Vladimirov, D. Vlasenko Lomonosov Moscow State University, SAI, Physics Department A. Tlatov, V.Senik, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory D. Buckley, South African Astronomical Observatory R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias O. Gres, N.M. Budnev, O.Ershova, Yu.Ishmuhametov Applied Physics Institute, Irkutsk State University V. Yurkov, A. Gabovich, Yu. Sergienko Blagoveschensk Educational State University, Blagoveschensk R. Podesta, Carlos Lopez, F. Podesta, C.Francile Observatorio Astronomico Felix Aguilar (OAFA) H. Levato Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) MASTER Global Robotic Net (http://observ.pereplet.ru , Lipunov et al. Advances in Astronomy, 2010, 30L http://adsabs.harvard.edu/abs/2010AdAst2010E..30L) started Swift GRB 181030A (Sonbas et al. GCN23389, Beardmore et al. GCN23391) optical alert observations 21 sec after notice time at 2018-10-30 01:29:03 UT MASTER-Kislovodsk robotic telescope, located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the GRB181030A 21 sec after notice time and 101 sec after trigger time at 2018-10-30 01:29:03 UT. On our first 20s expos. set , started at 2018-10-30 01:29:03 UT, we found optical transient within SWIFT error-box MASTER OT J094742.25+143925.73 (also detected by Sonbas et al SwiftUVOT GCN23389 and by Moskvitin et al. GCN 23390) with m_OT=16.5 and falling light curve in both polarization filters. The galactic latitude b = 46 deg., longitude l = 220 deg. The observations made on zenit distance = 47 deg. The moon (68 % bright part) was 67 deg. above the horizon.The distance between moon and object was 39 deg The sun altitude was -24.2 deg. MASTER-Tavrida robotic telescope located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the GRB181030A 31 sec after notice time and 105 sec after trigger time at 2018-10-30 01:29:13 UT. The observations started on zenit distance = 51 deg. The moon (68 % bright part) was 66 deg. above the horizon. The distance between moon and object was 39 The sun altitude was -27.9 deg. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23394 SUBJECT: GRB 181030A: Swift-XRT refined Analysis DATE: 18/10/30 12:14:27 GMT FROM: Phil Evans at U of Leicester P. D'Avanzo (INAF-OAB), S. J. LaPorte (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA) and E. Sonbas report on behalf of the Swift-XRT team: We have analysed 7.2 ks of XRT data for GRB 181030A (Sonbas et al. GCN Circ. 23389), from 148 s to 32.8 ks after the BAT trigger. The data comprise 121 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 23391). The light curve can be modelled with an initial power-law decay with an index of alpha=0.3 (+0.5, -0.7), followed by a break at T+179 s to an alpha of 1.815 (+0.024, -0.023). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.06 (+0.05, -0.04). The best-fitting absorption column is 5.3 (+1.9, -1.8) x 10^20 cm^-2, in excess of the Galactic value of 3.5 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.54 (+0.17, -0.14) and a best-fitting absorption column of 5.2 (+4.9, -1.7) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.2 x 10^-11 (4.5 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 5.2 (+4.9, -1.7) x 10^20 cm^-2 Galactic foreground: 3.5 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.54 (+0.17, -0.14) If the light curve continues to decay with a power-law decay index of 1.815, the count rate at T+24 hours will be 1.0 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.4 x 10^-14 (4.7 x 10^-14) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00869494. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23396 SUBJECT: GRB 181030A: RATIR Optical and NIR Observations DATE: 18/10/30 15:56:06 GMT FROM: Alan M. Watson at Instituto de Astronomia UNAM Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report: We observed the field of GRB 181030A (Sonbas et al., GCN Circ. 23389) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2018/10 30.41 to 2018/10 30.53 UTC (8.40 to 11.29 hours after the BAT trigger), obtaining a total of 0.82 hours exposure in the r and i bands and 0.39 hours exposure in the Z, Y, J, and H bands. For a source within the XRT error circle, in comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following upper limits (3-sigma): r > 22.25 i > 22.11 Z > 21.07 Y > 20.80 J > 20.31 H > 19.61 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. The afterglow has clearly faded since the early observations of Sonbas et al. (GCN Circ. 23389), Moskvitin & Spiridonova (GCN Circ. 23390), and Lipunov et al. (GCN Circ. 23392). We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23397 SUBJECT: GRB 181030A, Swift-BAT refined analysis DATE: 18/10/30 22:49:32 GMT FROM: Amy Lien at GSFC J. R. Cummings (CPI), S. D. Barthelmy (GSFC), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), E. Sonbas (Adiyaman Univ.), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 181030A (trigger #869494) (Sonbas et al., GCN Circ. 23389). The BAT ground-calculated position is RA, Dec = 146.916, 14.657 deg which is RA(J2000) = 09h 47m 39.8s Dec(J2000) = +14d 39' 26.5" with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 71%. The mask-weighted light curve shows a long pulse that starts at ~T0 and peaks at ~T+70 s. The main pulse emission ends at ~T+200 s, with some weak emission lasting till ~T+400 s. T90 (15-350 keV) is 304.7 +- 76.9 sec (estimated error including systematics). The time-averaged spectrum from T+3.2 to T+443.0 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.77 +- 0.09. The fluence in the 15-150 keV band is 6.2 +- 0.3 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+71.33 sec in the 15-150 keV band is 0.8 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/869494/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23400 SUBJECT: GRB 181030A: Swift/UVOT Detection DATE: 18/10/31 13:40:13 GMT FROM: Sam Emery at MSSL-UCL S.W.K. Emery (UCL-MSSL) and E. Sonbas (Adiyaman Univ.) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 181030A 152 s after the BAT trigger (Sonbas et al., GCN Circ. 23389). A fading source is detected in the initial UVOT exposures at a position consistent with the XRT position (Beardmore et al., GCN Circ. 23391) and also with SAO RAS (Moskvitin et al., GCN Circ. 23390) and MASTER Net (Lipunov et al., GCN Circ. 23392). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 152 270 116 19.34 +/- 0.30 white 3978 5614 393 >20.7 v 4389 6009 378 >18.9 b 3774 17487 635 >20.1 u 3569 17236 1278 >20.3 uvw1 4799 11747 852 >20.2 uvm2 4594 22498 1201 >20.7 uvw2 4184 5819 393 >20.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).