GRB150727A

This page lists all entries on GRB150727A in GRBweb

Summary Fermi GBM IPN Swift GCN 18076 GCN 18079 GCN 18080 GCN 18081 GCN 18082 GCN 18083 GCN 18084 GCN 18085 GCN 18086 GCN 18089 GCN 18095 GCN 18113

Summary table
Variable Value Source
GRB_name_Fermi GRB150727793
T0 19:01:54.812 UTC Fermi_GBM
ra 203.9688° Swift
decl -18.3253° Swift
pos_error 5.70e-05° Swift
T90 49.409 s Fermi_GBM
T90_error 3.974 s Fermi_GBM
T90_start 19:01:54.812 UTC Fermi_GBM
fluence 4.42e-06 erg/cm² Fermi_GBM
fluence_error 5.86e-08 erg/cm² Fermi_GBM
redshift 0.3130 GCN_circulars,Other
T100 95.188 s
GBM_located False
mjd 57230.79299550926 Fermi_GBM
Fermi GBM table
GRB_name_Fermi GRB150727793
trigger_name bn150727793
ra 203.9900°
decl -18.3600°
pos_error 4.41e+00°
datum 2015-07-27
t_trigger 19:01:56.348 UTC
T90 49.409 s
T90_error 3.974 s
T90_start 19:01:54.812 UTC
fluence 4.42e-06 erg/cm²
fluence_error 5.86e-08 erg/cm²
flux_1024 2.12e+00 erg/cm²/s
flux_1024_error 2.40e-01 erg/cm²/s
flux_1024_time 5.06e+00 erg/cm²/s
flux_64 4.67e+00 erg/cm²/s
flux_64_error 1.22e+00 erg/cm²/s
IPN table
GRB_name GRB150727A
ra 203.9917°
decl -18.3500°
pos_error 5.00e-02°
redshift 0.3130
Swift table
GRB_name GRB150727A
t_trigger 19:02:02 UTC
ra 203.9688°
decl -18.3253°
pos_error 5.70e-05°
T90 88.0 s
fluence 3.70e-06 erg/cm²
redshift 0.3130
GCN 18076 table
GRB_name GRB150727A
GCN_number 18076
Detection_method Swift Det
t_trigger 19:02:02 UTC
ra 203.9900°
decl -18.3550°
Circular_text TITLE: GCN CIRCULAR NUMBER: 18076 SUBJECT: GRB 150727A: Swift detection of a burst with an optical counterpart DATE: 15/07/27 19:24:14 GMT FROM: Scott Barthelmy at NASA/GSFC S. B. Cenko (GSFC), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 19:02:02 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150727A (trigger=650530). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 203.990, -18.355, which is RA(J2000) = 13h 35m 58s Dec(J2000) = -18d 21' 16" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a large FRED-like peak structure with a duration of about 60 sec. The peak count rate was ~2795 counts/sec (15-350 keV), at ~4 sec after the trigger. The XRT began observing the field at 19:03:19.5 UT, 77.2 seconds after the BAT trigger. XRT found a bright, fading, uncatalogued X-ray source located at RA, Dec 203.9705, -18.3259 which is equivalent to: RA(J2000) = +13h 35m 52.92s Dec(J2000) = -18d 19' 33.2" with an uncertainty of 4.7 arcseconds (radius, 90% containment). This location is 124 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 8.93e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 86 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 13:35:52.52 = 203.96883 DEC(J2000) = -18:19:31.4 = -18.32539 with a 90%-confidence error radius of about 0.62 arc sec. This position is 6.0 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.31 with a 1-sigma error of about 0.15. No correction has been made for extinction. Burst Advocate for this burst is S. B. Cenko (brad.cenko AT nasa.gov). 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 18079 table
GRB_name GRB150727A
GCN_number 18079
Detection_method Swift-XRT Det
ra 203.9684°
decl -18.3258°
Circular_text TITLE: GCN CIRCULAR NUMBER: 18079 SUBJECT: GRB 150727A: Enhanced Swift-XRT position DATE: 15/07/27 23:59:12 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 1662 s of XRT Photon Counting mode data and 4 UVOT images for GRB 150727A, 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 = 203.96843, -18.32576 which is equivalent to: RA (J2000): 13h 35m 52.42s Dec (J2000): -18d 19' 32.7" with an uncertainty of 1.8 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.
GCN 18080 table
GRB_name GRB150727A
GCN_number 18080
Detection_method Other
redshift 0.3130
Circular_text TITLE: GCN CIRCULAR NUMBER: 18080 SUBJECT: GRB 150727A: VLT/X-shooter redshift DATE: 15/07/28 05:14:42 GMT FROM: Nial Tanvir at U.Leicester N. R. Tanvir (U. Leicester), D. Xu (NAOC/CAS), T. Zafar (ESO), S. Covino (INAF/OABr), S. Schulze (PUC, MAS) report for a larger collaboration: We observed the afterglow of GRB 150727A (Cenko et al. GCN 18076) with VLT/X-shooter, beginning at 2015-07-28 00:01 UT, about 5 hr after the burst. Preliminary analysis of the spectrum reveals emission lines of Halpha, Hbeta and [OIII] 4959/5007 at a redshift of z=0.313. There is only marginal evidence of the [OII] 3727 doublet, suggesting the emission lines are coming from a dust obscured region (consistent also with a high Ha:Hb ratio). The continuum is faint with no clear absorption lines, but can be traced in the blue as far as the instrumental cut-off at about 3100A. Despite the absence of detected absorption features, it is likely that the emission lines are from the host galaxy and therefore that this redshift is also that of the GRB.
GCN 18081 table
GRB_name GRB150727A
GCN_number 18081
Detection_method Fermi GBM Det
t_trigger 19:01:56.350 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 18081 SUBJECT: GRB 150727A: Fermi GBM detection DATE: 15/07/28 06:25:51 GMT FROM: George A. Younes at George Washington U G. Younes (GWU) reports on behalf of the Fermi GBM Team: "At 19:01:56.35 UT on July 27 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150727A (trigger 459716520/150727793), which was also detected by Swift (Cenko et al. 2015, GCN 18076). The GBM on-ground location, using the Fermi GBM trigger data, is consistent with the Swift/XRT location. The angle of the burst direction to the Fermi LAT boresight is 46 degrees. The GBM light curve shows a FRED-like (fast-rise exponential-decay) pulse with a duration (T90) of about 50s (50-300 keV). The time-averaged spectrum from T0-4s to T0+56s is well fit by a power law with an exponential high-energy cutoff. The power law index is -0.7 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 149 +/- 10 keV. The event fluence (10-1000 keV) in this time interval is (7.9 +/- 0.3)E-06 ergs/cm^2. The 1.0-sec peak photon flux measured starting from T0+5.0s in the 10-1000 keV band is 2.1 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN 18082 table
GRB_name GRB150727A
GCN_number 18082
Detection_method Swift-XRT Other
redshift 0.3130
Circular_text TITLE: GCN CIRCULAR NUMBER: 18082 SUBJECT: GRB 150727A: Swift-XRT refined Analysis DATE: 15/07/28 08:24:02 GMT FROM: Phil Evans at U of Leicester K.L. Page (U. Leicester), C. Pagani (U. Leicester), A. D'ai (INAF-IASFPA), A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A.P. Beardmore (U. Leicester) and S.B. Cenko report on behalf of the Swift-XRT team: We have analysed 8.0 ks of XRT data for GRB 150727A (Cenko et al. GCN Circ. 18076), from 68 s to 32.5 ks after the BAT trigger. The data comprise 523 s in Windowed Timing (WT) mode (the first 8 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 18079). The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=1.2 (+/-0.4). At T+93.8 s the decay steepens to an alpha of 2.72 (+0.11, -0.08). The light curve breaks again at T+195 s to a decay with alpha=1.42 (+0.07, -0.06), and again at T+3169 s s to alpha=8.0 (+0.0, -5.8), before a final break at T+4539 s s after which the decay index is 0.5 (+/-0.3). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.39 (+/-0.04). The best-fitting absorption column is 2.0 (+/-1.5) x 10^20 cm^-2, at a redshift of 0.313, in addition to the Galactic value of 9.8 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.7 x 10^-11 (3.9 x 10^-11) erg cm^-2 count^-1. A summary of the WT-mode spectrum is thus: Galactic foreground: 9.8 x 10^20 cm^-2 Intrinsic column: 2.0 (+/-1.5) x 10^20 cm^-2 at z=0.313 Photon index: 2.39 (+/-0.04) If the light curve continues to decay with a power-law decay index of 0.5, the count rate at T+24 hours will be 8.7 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.4 x 10^-13 (3.4 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/00650530. This circular is an official product of the Swift-XRT team.
GCN 18083 table
GRB_name GRB150727A
GCN_number 18083
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 18083 SUBJECT: GRB 150727A: LCOGT-Cerro Tololo observations DATE: 15/07/28 10:03:02 GMT FROM: Simone Dichiara at Ferrara U/Italy S. Dichiara, C. Guidorzi (U. Ferrara), C.G. Mundell (U. Bath), S. Kobayashi (LJMU), A. Gomboc (U. Ljubljana) on behalf of a large collaboration report: Using a 1-m LCOGTN telescope in Cerro Tololo (Chile), we began observing GRB 150727A (Cenko et al. GCN 18076; Younes et al. GCN 18081) on July 28 01:23:01 UT (~6.3 hours after the burst trigger) with r' and i' filters. We did not detect the UVOT counterpart (Cenko et al. 2015, GCN 18076) down to the following limit: Mid time from Total Exp Filter Magnitude trigger (hr) (s) ------------------------------------------------- 6.71 120x10 r' > 18.9 6.76 120x9 i' > 16.5 ------------------------------------------------- Values have been calibrated against nearby USNOB-1 stars (R2 and I).
GCN 18084 table
GRB_name GRB150727A
GCN_number 18084
Detection_method Swift-UVOT Det
ra 203.9688°
decl -18.3254°
Circular_text TITLE: GCN CIRCULAR NUMBER: 18084 SUBJECT: GRB 150727A: Swift/UVOT Detection DATE: 15/07/28 10:38:48 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (UCL-MSSL) and S. B. Cenko (GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 150727A 86 s after the BAT trigger (Cenko et al., GCN Circ. 18076). A fading source consistent with the enhanced XRT position (Osborne et al. GCN Circ. 18079) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 13:35:52.52 = 203.96885 (deg.) Dec (J2000) = -18:19:31.3 = -18.32536 (deg.) with an estimated uncertainty of 0.44 arc sec. (radius, 90% confidence). Preliminary detections in the white, u and uvw2 filters and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 86 236 147 18.28 ± 0.06 white 578 598 20 18.75 ± 0.24 v 4036 4236 197 >18.7 b 554 574 19 >18.5 u 298 548 246 18.75 ± 0.16 m2 4241 4379 136 >19.1 w2 3831 4031 197 19.53 ± 0.36 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening in the direction of the burst.
GCN 18085 table
GRB_name GRB150727A
GCN_number 18085
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18085 SUBJECT: GRB 150727A: Watcher optical upper limit DATE: 15/07/28 10:39:46 GMT FROM: Antonio Martin-Carrillo at UCD,Space Science Group A. Martin-Carrillo (UCD), D. Murphy (UCD), L. Hanlon (UCD), M. Topinka (CTU), H. J. van Heerden (UFS), B. van Soelen (UFS) and P. J. Meintjes (UFS): We observed the field of GRB 150727A (Cenko et al., GCN Circ. #18076) using the 40cm UCD Watcher telescope at Boyden Observatory in South Africa. Observations started at 19:19:55 UT, 1073 seconds after the burst trigger. A series of 60 sec images were taken in the SDSS r' filter using an Andor CCD camera. No afterglow candidate is detected in any of the individual images at the UVOT location. A 3sigma upper limit for a combined 180 second exposure is given below. Start | End | Exposure | Filter | Magnitude ------------------------------------------------------------------------------------------------- 19:19:55 UT | 19:25:20 UT | 3x60 sec | r' | >17.59 (3sigma upper limit) The upper limit was calculated using nearby stars from the APASS catalogue. This message can be cited in publications.
GCN 18086 table
GRB_name GRB150727A
GCN_number 18086
Detection_method Swift-BAT Det
ra 203.9680°
decl -18.3200°
Circular_text TITLE: GCN CIRCULAR NUMBER: 18086 SUBJECT: GRB 150727A: Swift-BAT refined analysis DATE: 15/07/28 12:05:52 GMT FROM: Scott Barthelmy at NASA/GSFC M. Stamatikos (OSU), S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), 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 downlinks, we report further analysis of BAT GRB 150727A (trigger #650530) (Cenko, et al., GCN Circ. 18076). The BAT ground-calculated position is RA, Dec = 203.968, -18.320 deg, which is RA(J2000) = 13h 35m 52.3s Dec(J2000) = -18d 19' 11.4" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 68%. The mask-weighted light curve shows a FRED-like peak starting at ~T-8 sec, peaking at ~T+5 sec, and ramping down to a flat level at ~T+80 sec. There is a second, small peak at ~T+90 sec. The low level emission continues (with a weak decline) out to T+870 sec when observations stop due to an observing constraint. T90 (15-350 keV) is 88 +- 13 sec (estimated error including systematics). The time-averaged spectrum from T-8.70 to T+95.94 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.14 +- 0.07. The fluence in the 15-150 keV band is 3.7 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+9.21 sec in the 15-150 keV band is 1.0 +- 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/650530/BA/ [GCN OPS NOTE(29jul15): Per author's request, the typo on the uncertainty in the T90 value was changed from 133 to 13 sec.]
GCN 18089 table
GRB_name GRB150727A
GCN_number 18089
Detection_method Swift-XRT Other
ra 203.9688°
decl -18.3254°
redshift 0.3130
Circular_text TITLE: GCN CIRCULAR NUMBER: 18089 SUBJECT: GRB 150727A: RATIR Optical Observations DATE: 15/07/28 16:43:42 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), 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), 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 150727A (Cenko et al., GCN 18076) 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 2015/07 28.15 to 2015/07 28.21 UTC (8.65 to 9.95 hours after the BAT trigger), obtaining a total of 1.07 hours exposure in the r, i, and z bands. We detect a source at the edge of the Swift/XRT error circle (Osborne et al., GCN 18079), at RA, Dec (J2000) = 13:35:52.52, -18:19:31.4 (0.5"). In comparison with the USNO-B1 and 2MASS catalogs, we obtain the following detections and upper limits (3-sigma): r 21.13 0.19 i 21.40 0.13 z > 19.57 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. Our detections appear to be consistent with the non-detections at shallower depths reported by Dichiara et al. (GCN 18083). Tanvir et al. (GCN 18080) report a tentative spectroscopic redshift of 0.313. Further observations are planned. We thank the staff of the Observatorio Astronmico Nacional in San Pedro Mrtir.
GCN 18095 table
GRB_name GRB150727A
GCN_number 18095
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 18095 SUBJECT: GRB 150727A: Continued RATIR Optical Observations - Fading DATE: 15/07/29 20:03:54 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), 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), 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 150727A (Cenko et al., GCN 18076) 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 2015/07 29.15 to 2015/07 29.19 UTC (32.64 to 33.50 hours after the BAT trigger), obtaining a total of 0.70 hours exposure in the r, i, and z bands. We no longer detect the source seen on the previous night (Watson et al., GCN 18089). In comparison with the USNO-B1 and 2MASS catalogs, we obtain the following upper limits (3-sigma): r > 22.27 i > 22.61 z > 19.11 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. The source has faded by at least 1 magnitude in both r and i. We therefore suggest that it it corresponds to the afterglow. We thank the staff of the Observatorio Astronmico Nacional in San Pedro Mrtir.
GCN 18113 table
GRB_name GRB150727A
GCN_number 18113
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 18113 SUBJECT: GRB 150727A: IRSF NIR observation DATE: 15/08/04 08:45:32 GMT FROM: Daisuke Kuroda at OAO/NAOJ K. L. Murata (Nagoya U.), T. Kusune (Nagoya City U.), H. Onozato (Tohoku U.) and T. Nagayama (Kagoshima U.) We observed the field of GRB 150727A (Cenko et al., GCN Circular #18076) with the near-infrared (J, H, Ks) simultaneous imaging polarimeter SIRPOL attached to 1.4 m telescope IRSF (InfraRed Survey Facility) in Sutherland observatory, South Africa. The observations started on 2015-07-27 19:25:30 UT (~ 9 min. after the burst). We detected an uncatalogued source within 5 arcsec from the Swift/UVOT preliminary position reported in the GCN circular of Breeveld et al. (GCN Circular #18084). We have obtained the following preliminary magnitude (Vega magnitude system): J = 18.9 +- 0.2 H = 18.1 +- 0.1 Ks = 17.1 +- 0.2 Given magnitudes were calibrated against 2MASS point sources in this field. This observation was carried out by IRSF and OISTER collaboration.