GRB140518A

This page lists all entries on GRB140518A in GRBweb

Summary IPN Swift GCN 16298 GCN 16299 GCN 16300 GCN 16301 GCN 16302 GCN 16303 GCN 16304 GCN 16305 GCN 16306 GCN 16308 GCN 16309

Summary table
Variable Value Source
T0 9:17:46 UTC GCN_circulars,Swift Det
ra 227.2525° Swift
decl 42.4182° Swift
pos_error 1.94e-04° Swift
T90 60.5 s Swift
T90_start 9:17:46 UTC Swift
fluence 1.00e-06 erg/cm² Swift
redshift 4.7070
T100 60.5 s
GBM_located False
mjd 56795.387337962966 GCN_circulars,Swift Det
IPN table
GRB_name GRB140518A
ra 227.2292°
decl 42.4000°
pos_error 5.00e-02°
redshift 4.7070
Swift table
GRB_name GRB140518A
t_trigger 9:17:46 UTC
ra 227.2525°
decl 42.4182°
pos_error 1.94e-04°
T90 60.5 s
fluence 1.00e-06 erg/cm²
redshift 4.7070
GCN 16298 table
GRB_name GRB140518A
GCN_number 16298
Detection_method Swift Det
t_trigger 9:17:46 UTC
ra 227.2690°
decl 42.4160°
Circular_text TITLE: GCN CIRCULAR NUMBER: 16298 SUBJECT: GRB 140518A: Swift detection of a burst DATE: 14/05/18 09:43:46 GMT FROM: David Palmer at LANL A. Melandri (INAF-OAB), M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), D. Malesani (DARK/NBI), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 09:17:46 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 140518A (trigger=599287). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 227.269, +42.416 which is RA(J2000) = 15h 09m 05s Dec(J2000) = +42d 24' 56" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a multiple-peaked structure with a duration of about 60 s. The peak count rate was ~1500 counts/s (15-350 keV) at ~0 sec after trigger. The XRT began observing the field at 09:18:55.0 UT, 69 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source with an enhanced position: RA, Dec 227.2519, 42.4185 which is equivalent to: RA(J2000) = 15h 09m 00.45s Dec(J2000) = +42d 25' 06.6" with an uncertainty of 2.0 arcseconds (radius, 90% containment). This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (1.56 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 2.5 (+2.30/-2.03) x 10^21 cm^-2 (90% confidence). The initial flux in the 2.5 s image was 3.67e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 76 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. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. Burst Advocate for this burst is A. Melandri (andrea.melandri AT brera.inaf.it). 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.)
GCN 16299 table
GRB_name GRB140518A
GCN_number 16299
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 16299 SUBJECT: GRB 140518A: KAIT optical candidate DATE: 14/05/18 10:17:13 GMT FROM: Weikang Zheng at UC Berkeley WeiKang Zheng, Alexei V. Filippenko, Adam Morgan (UC Berkeley), and S. B. Cenko (NASA/Goddard Space Flight Center) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to GRB 140518A (Swift trigger 599287; Melandri et al., GCN 16298) starting at 09:22:16 UT, 270 s after the burst. Observations were performed with an automatic sequence in the clear (roughly R), V and I filters, and the exposure time was 20 s per image. We detect a faint object within XRT error circle at J2000 coordinates of: RA = 15:09:00.62 DEC= +42:25:05.9 with uncertainty of about 1". The object was only detected in the first clear band single image with mag R~18.3, no detection in following single images. But it is marginally detected in the co-add of next 5 single images with mag R~19.0. We suggest this to be the afterglow of the GRB. All mags are calibrated to USNO B1.0 catalog. [GCN OPS NOTE(18may14): Per author's request, the Subject-line was corrected from "140418A" to "140518A".]
GCN 16300 table
GRB_name GRB140518A
GCN_number 16300
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 16300 SUBJECT: GRB 140518A: P60 i-/z-band detections DATE: 14/05/18 12:22:01 GMT FROM: Daniel Perley at Caltech D. A. Perley (Caltech) reports on behalf of a larger collaboration The Palomar 60-inch telescope responded automatically to the Swift trigger for GRB 140518A (Melandri et al., GCN 16298) and began a repeating cycle of 60-second exposures in r, i, and z-band observations at 09:22:28 UT, 4.70 minutes after the burst. We weakly detect the afterglow reported by Zheng et al. (GCN 16299) in the i and z filters, but not in r-band. Only marginal detections are evident in any individual exposure in any filter, but a stack of the first six exposures in each band gives magnitudes (calibrated relative to SDSS) of: r > 20.31 (2 sigma) i = 19.03 +/- 0.16 z = 18.20 +/- 0.17 at a mid-time of approximately 16 minutes after the burst.
GCN 16301 table
GRB_name GRB140518A
GCN_number 16301
Detection_method Optical
redshift 4.7070
Circular_text TITLE: GCN CIRCULAR NUMBER: 16301 SUBJECT: GRB 140518A: Gemini-N redshift DATE: 14/05/18 14:01:58 GMT FROM: Ryan Chornock at Harvard R. Chornock (Harvard), D. B. Fox (Penn State), A. Cucchiara (Goddard), D. A. Perley (Caltech), and A. Levan (Warwick) report on behalf of a larger collaboration: We obtained 2x900s of spectroscopy of the optical afterglow (Zheng et al., GCN 16299; Perley et al., GCN 16300) of GRB140518A (Melandri et al., GCN 16298) using GMOS on the 8-m Gemini-North telescope starting at 12:22 UT on May 18. Our spectra covered the wavelength range 5900-10150 Angstroms at a resolution of R~1200. A damped Lyman-alpha system is present near 6940 Angs, corresponding to z~4.71. A fit to the absorber gives z=4.706 and the log of the HI column density (in cm^-2) is 21.65 +- 0.1. Strong narrow absorption lines of S II, Si II, Si II*, O I, O I*, Si IV, C II, C IV, Fe II, and Al II associated with this absorption system have a common redshift of z=4.707. The combination of the DLA and the excited fine structure lines allow us to identify this as the redshift of the GRB. We thank the Gemini staff, in particular Rachel Mason and Joy Chavez, for their assistance with these observations.
GCN 16302 table
GRB_name GRB140518A
GCN_number 16302
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 16302 SUBJECT: GRB 140518A: RATIR Optical and NIR Observations DATE: 14/05/18 14:24:59 GMT FROM: Antonino Cucchiara at NASA/GSFC A. Cucchiara (NASA/GSFC), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid Georgiev (UNAM), Jess Gonzlez (UNAM), Carlos Romn-Ziga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report: We observed the field of GRB 140518A (Melandri, et al., GCN 16298) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronmico Nacional on Sierra San Pedro Mrtir from 2014/05 18.41 to 2014/05 18.46 UTC (0.60 to 1.75 hours after the BAT trigger), obtaining a total of 0.71 hours exposure in the r and i bands and 0.30 hours exposure in the Z, Y, J, and H bands. We detect the fading source identified by Zheng et al. (GCN 16299) and Perley et al. (GCN 16300) within the Swift-XRT error circle. We confirm this to be the optical afterglow of GRB 140518A. In comparison with the SDSS DR9 and 2MASS, we obtain the following detections: r 20.50 +/- 0.04 i 19.00 +/- 0.02 Z 18.59 +/- 0.03 Y 18.19 +/- 0.03 J 18.13 +/- 0.02 H 17.80 +/- 0.02 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. Based on these observations, and using our automatic photo-z analysis tool (Littlejohns et al. arXiv:1312.3967) we determine two possible photometric redshifts: assuming a Milky Way extinction curve for the GRB host we derive a photo-z of z=1.88 (+- 0.06) and A_V=1.8, while a SMC extinction law gives a z=4.63 (+- 0.11) and A_V=0.5. The second solution is consistent with the spectroscopic redshift reported by Chornock et al. (GCN 16301). We thank the staff of the Observatorio Astronmico Nacional in San Pedro Mrtir. [GCN OPS NOTE(19may14): Per author's request, the "9.90 to 11.05" was changed to "0.60 to 1.75".]
GCN 16303 table
GRB_name GRB140518A
GCN_number 16303
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 16303 SUBJECT: GRB 140518A: Swift/UVOT Upper Limits DATE: 14/05/18 17:18:01 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (UCL-MSSL) and A. Melandri (INAF-OAB) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 140518A 77 s after the BAT trigger (Melandri et al., GCN Circ. 16298). No optical afterglow consistent with the XRT position (Melandri et al. GCN Circ. 16298) is detected in the initial UVOT exposures. Preliminary 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 77 226 147 >20.7 u_FC 289 539 246 >20.7 white 77 13719 1583 >22.6 v 619 7499 568 >20.2 b 545 12953 1060 >22.0 u 289 12041 1286 >21.6 w1 668 7910 568 >21.4 m2 1071 7705 413 >21.1 w2 595 7295 510 >21.3 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998).
GCN 16304 table
GRB_name GRB140518A
GCN_number 16304
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 16304 SUBJECT: GRB 140518A: Skynet GORT Detections of the Optical Afterglow DATE: 14/05/18 18:24:41 GMT FROM: Adam S. Trotter at UNC-Chapel Hill/PROMPT/Skynet A. Trotter, A. LaCluyze, J. Haislip, D. Reichart, K. McLin, L. Cominsky, H. T. Cromartie, A. Foster, N. Frank, K. Ivarsen, M. Maples, J. Moore, M. Nysewander, R. Beauchemin, T. Berger, A. Dow, M. Hinckle, A. Patterson, H. Pegues, J. Pozo, D. Waddell, and J. A. Crain report: Skynet observed the Swift-XRT localization of GRB 140518A (Melandri et al., GCN 16298, Swift trigger 599287) with the 14" GLAST Optical Robotic Telescope (GORT) at the Hume observatory in CA, USA. Observations began at t=130s and continued until 2.4h post-trigger. Skynet took alternating exposures in the Rc and Ic bands, increasing from 10s to 160s. In early Ic and Rc images, and in later stacked Ic images, we detect an uncatalogued fading optical source at a position consistent with the afterglow candidate reported by Zheng et al. (GCN 16299). The source faded from Ic=16.8 at t=130s to Ic > 18.7 at a mean time t~70m. In Rc band, we detect the source marginally at Rc~18.3 at t=4m, with Rc>20.1 at a mean time t~55m. A preliminary light curve is at: http://www.skynet.unc.edu/grb/grb140518a.png Photometry is calibrated to six APASS-DR7 stars in the field, and has not been corrected for the Galactic foreground extinction corresponding to E(B-V)=0.016 (Schlegel et al. 1998). No further Skynet observations are scheduled.
GCN 16305 table
GRB_name GRB140518A
GCN_number 16305
Detection_method Swift-XRT Other
ra 227.2525°
decl 42.4182°
redshift 4.7070
Circular_text TITLE: GCN CIRCULAR NUMBER: 16305 SUBJECT: GRB 140518A: Swift-XRT refined Analysis DATE: 14/05/18 21:44:05 GMT FROM: Phil Evans at U of Leicester A. Maselli (INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), V. Mangano (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester) and A. Melandri report on behalf of the Swift-XRT team: We have analysed 8.3 ks of XRT data for GRB 140518A (Melandri et al. GCN Circ. 16298), from 58 s to 19.5 ks after the BAT trigger. The data comprise 92 s in Windowed Timing (WT) mode (the first 8 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. Using 4543 s of PC mode data and 6 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 227.25249, +42.41821 which is equivalent to: RA (J2000): 15h 09m 00.60s Dec(J2000): +42d 25' 05.6" with an uncertainty of 1.5 arcsec (radius, 90% confidence). The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=3.42 (+0.22, -0.19). At T+251 s the decay flattens to an alpha of 0.25 (+0.15, -0.18) before breaking again at T+2747 s to a final decay with index alpha=1.51 (+0.32, -0.27). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.66 (+/-0.10). The best-fitting absorption column is 2.5 (+1.7, -1.6) x 10^22 cm^-2, at a redshift of 4.707, in addition to the Galactic value of 1.6 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.94 (+/-0.12) and a best-fitting absorption column of 2.9 (+1.7, -1.6) x 10^22 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (3.8 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Galactic foreground: 1.6 x 10^20 cm^-2 Intrinsic column: 2.9 (+1.7, -1.6) x 10^22 cm^-2 at z=4.707 Photon index: 1.94 (+/-0.12) If the light curve continues to decay with a power-law decay index of 1.51, the count rate at T+24 hours will be 2.0 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.9 x 10^-14 (7.8 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/00599287. This circular is an official product of the Swift-XRT team.
GCN 16306 table
GRB_name GRB140518A
GCN_number 16306
Detection_method Swift-BAT Det
ra 227.2310°
decl 42.3960°
Circular_text TITLE: GCN CIRCULAR NUMBER: 16306 SUBJECT: GRB 140518A, Swift-BAT refined analysis DATE: 14/05/19 00:27:52 GMT FROM: Amy Lien at GSFC T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC), C. B. Markwardt (GSFC), A. Melandri (INAF-OAB), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 140518A (trigger #599287) (Melandri, et al., GCN Circ. 16298). The BAT ground-calculated position is RA, Dec = 227.231, 42.396 deg which is RA(J2000) = 15h 08m 55.3s Dec(J2000) = +42d 23' 44.2" with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 89%. The mask-weighted light curve shows multiple peaks with roughly three main pulse structures. The first main pulse starts at ~T-4 s and ends at ~T+8 s. The second main pulse starts at ~T+38 s, followed immediately by the third main pulse structure that starts at ~T+48 s and ends at ~T+61 s. Additionally, each of these main pulse structure contains several sub-pulses. T90 (15-350 keV) is 60.5 +- 2.4 sec (estimated error including systematics). The time-averaged spectrum from T-4.1 to T+60.0 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.92 +- 0.61, and Epeak of 43.9 +- 7.6 keV (chi squared 54.15 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.0 +- 0.1 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+41.94 sec in the 15-150 keV band is 1.0 +- 0.1 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.97 +- 0.13 (chi squared 65.02 for 57 d.o.f.). 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/599287/BA/
GCN 16308 table
GRB_name GRB140518A
GCN_number 16308
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 16308 SUBJECT: GRB 140518A: Continued RATIR Optical and NIR Observations DATE: 14/05/19 15:01:09 GMT FROM: Nat Butler at Az State U Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report: We observed the field of GRB 140518A (Melandri, et al., GCN 16298) 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 2014/05 19.24 to 2014/05 19.46 UTC (20.37 to 25.71 hours after the BAT trigger), obtaining a total of 2.47 hours exposure in the r and i bands and 2.06 hours exposure in the Z an J bands. For a source at the optical transient position (Zheng et al., GCN 16299), in comparison with the SDSS DR9 and 2MASS, we obtain the following upper limits (3-sigma): r > 22.03 i > 22.20 Z > 21.28 J > 21.07 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. Compared to our observations last night (Cucchiara, et al., GCN 16302), during which the source faded approximately as t^(-0.5), the source has now apparently faded more rapidly as t^(-1) or faster. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.
GCN 16309 table
GRB_name GRB140518A
GCN_number 16309
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 16309 SUBJECT: GRB 140518A: T100 observations DATE: 14/05/19 16:13:14 GMT FROM: Eda Sonbas at NASA/GSFC E. Sonbas (Adiyaman Univ.), T. Guver (Istanbul Univ.), U. Temiz, F.Dolek (Cukurova Univ.), E. Gogus (Sabanci Univ.), O. Erece (Akdeniz Univ.), O. Basturk (Ankara Univ.) report on behalf of a larger collaboration We observed the field of Swift GRB 140518A (Melandri et al., GCN#16298) with the 1.0 meter T100 telescope (Bakirlitepe, TUBITAK National Observatory, Turkey), starting May, 18, 21:35:41 UT (~ 12.3 hours after the trigger). 5 x 300 s exposures were obtained in the R filter under moderate weather conditions. We do not detect an optical afterglow within the reported XRT error circle down to a limiting magnitude of >20.37 (2-sigma) in the combined R band image. We are grateful to TUBITAK National Observatory for prompt scheduling the observations and technical support.