//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22695 SUBJECT: GRB 180510A: Swift detection of a burst DATE: 18/05/10 19:47:25 GMT FROM: Boris Sbarufatti at PSU J.D. Gropp (PSU), A. Deich (PSU), J. A. Kennea (PSU), S. J. LaPorte (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), B. Sbarufatti (PSU), M. H. Siegel (PSU) and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 19:24:34 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 180510A (trigger=831810). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 276.318, -31.911 which is RA(J2000) = 18h 25m 16s Dec(J2000) = -31d 54' 38" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 70 sec. The peak count rate was ~8000 counts/sec (15-350 keV), at ~5 sec after the trigger. The XRT began observing the field at 19:26:02.5 UT, 88.3 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 276.3303, -31.9069 which is equivalent to: RA(J2000) = +18h 25m 19.27s Dec(J2000) = -31d 54' 24.8" with an uncertainty of 5.5 arcseconds (radius, 90% containment). This location is 40 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 1.09e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 96 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the sub-image. Results from the list of sources generated on-board are not available at this time. No correction has been made for the expected extinction corresponding to E(B-V) of 0.26. Burst Advocate for this burst is J.D. Gropp (jdg44 AT psu.edu). 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: 22707 SUBJECT: GRB 180510A: Swift-XRT refined Analysis DATE: 18/05/11 19:47:04 GMT FROM: Phil Evans at U of Leicester A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB) and J.D. Gropp report on behalf of the Swift-XRT team: We have analysed 4.9 ks of XRT data for GRB 180510A (Gropp et al. GCN Circ. 22695), from 77 s to 40.5 ks after the BAT trigger. The data comprise 228 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The refined XRT position is RA, Dec = 276.3314, -31.9081 which is equivalent to: RA (J2000): 18 25 19.54 Dec(J2000): -31 54 29.1 with an uncertainty of 3.6 arcsec (radius, 90% confidence). The late-time light curve (from T0+15.8 ks) can be modelled with a power-law decay with a decay index of alpha=1.2 (+/-0.4). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.94 (+0.08, -0.07). The best-fitting absorption column is 5.2 (+/-0.5) x 10^21 cm^-2, in excess of the Galactic value of 2.1 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.01 (+0.30, -0.28) and a best-fitting absorption column of 3.5 (+1.4, -1.2) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.8 x 10^-11 (5.8 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3.5 (+1.4, -1.2) x 10^21 cm^-2 Galactic foreground: 2.1 x 10^21 cm^-2 Excess significance: 1.9 sigma Photon index: 2.01 (+0.30, -0.28) If the light curve continues to decay with a power-law decay index of 1.2, the count rate at T+24 hours will be 0.016 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.2 x 10^-13 (9.4 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00831810. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22709 SUBJECT: GRB 180510A: Swift/UVOT followup observations DATE: 18/05/12 07:21:32 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (UCL-MSSL), S. R. Oates (U.Warwick) and J. D. Gropp (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 180510A 97 s after the BAT trigger (Gropp et al., GCN Circ. 22695). A source is detected at the edge of the refined XRT position (D’Ai et al. GCN Circ. 22707) but this is consistent with the position of a USNO-B1.0 source (at 276.332, -31.908), and it is not clear if we see any fading. 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 97 247 147 20.0 ± 0.3 white 28989 29010 21 >19.2 v 22961 23272 301 >19.4 b 28076 28983 885 20.2 ± 0.2 u 310 322 12 >17.6 uvw1 15854 16753 886 >20.6 uvw2 22055 22955 886 >20.5 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.26 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22722 SUBJECT: Konus-Wind observation of GRB 180510A DATE: 18/05/14 11:16:13 GMT FROM: Anastasia Tsvetkova at Ioffe Institute A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 180510A (Swift detection of a burst: Gropp et al., GCN 22695; Ukwatta et al., GCN 22704) triggered Konus-Wind at T0=69881.488 s UT (19:24:41.488). The burst light curve shows a single pulse which starts at ~T0-6.4 s and has a total duration of ~23.5 s. The emission is seen up to ~1 MeV. As observed by Konus-Wind, the burst had a fluence of 1.07(-0.14,+0.21)x10^-5 erg/cm2, and a 64-ms peak energy flux, measured from T0-0.064 s, of 3.53(-1.13,+1.18)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum of the burst (measured from T0 to T0+16.640 s) is best fit in the 20 keV - 1.5 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with  alpha = -1.14(-0.31,+0.38), and Ep = 237(-56,+126) keV (chi2 = 93/60 dof). Fitting by the GRB (Band) model yields alpha = -0.62(-0.66,+1.24), Ep = 150(-54,+131) keV, and an upper limit on the high energy photon index: beta < -1.90 (chi2 = 91/59 dof). The spectrum near the peak count rate (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 1 MeV range by a power law with exponential cutoff model with  alpha = -0.97(-0.30,+0.35), and Ep = 202(-34,+54) keV (chi2 = 75/50 dof). Fitting by the GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.37 (chi2 = 75/49 dof). The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB180510_T69881/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22730 SUBJECT: GRB 180510A: MITSuME Ishigakijima optical upper limits DATE: 18/05/15 01:02:37 GMT FROM: Ryosuke Itoh at Tokyo Institute of Tech. T. Horiuchi, H. Hanayama, M. Honma (IAO, NAOJ), R. Itoh, K. L. Murata and N. Kawai (Tokyo Tech) report on behalf of the MITSuME and OISTER collaboration: We observed the field of GRB 180510A (Gropp et al.,GCN 22695) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory. The observation started on 2018-05-10 19:29:21 UT, (287 seconds after the burst). No new or fading source is detected within the Swift-XRT error circle. We note that there is faint (~20mag) source detected in DSS images within XRT error circle (at 18:25:19.2, -31:54:22.7) but the source did not shows temporal variability during observation (~45 min). we derive the following upper limits using UCAC-4 catalog for flux calibration. #T0+[sec] MID-UT T-EXP[sec] g' Rc Ic ------------------------------------------------------------------- 287 19:55:17 2700.0 >19.4 >20.4 >20.2 ------------------------------------------------------------------- T0+ : Elapsed time after the burst [hour] T-EXP: Total Exposure time [sec]