GRB100615A

This page lists all entries on GRB100615A in GRBweb

Summary Fermi GBM IPN Swift GCN 10841 GCN 10842 GCN 10843 GCN 10844 GCN 10847 GCN 10848 GCN 10850 GCN 10851 GCN 10856 GCN 10858 GCN 10861 GCN 10915 GCN 10928 GCN 14264

Summary table
Variable Value Source
GRB_name_Fermi GRB100615083
T0 1:59:03 UTC GCN_circulars,Swift Det
ra 177.2054° Swift
decl -19.4812° Swift
pos_error 1.81e-04° Swift
T90 37.377 s Fermi_GBM
T90_error 0.979 s Fermi_GBM
T90_start 1:59:04.691 UTC Fermi_GBM
fluence 8.72e-06 erg/cm² Fermi_GBM
fluence_error 8.20e-08 erg/cm² Fermi_GBM
redshift 1.3980 GCN_circulars,Swift-XRT Other
T100 39.068 s
GBM_located False
mjd 55362.08267361111 GCN_circulars,Swift Det
Fermi GBM table
GRB_name_Fermi GRB100615083
trigger_name bn100615083
ra 177.2042°
decl -19.4819°
pos_error 3.47e+00°
datum 2010-06-15
t_trigger 1:59:04.371 UTC
T90 37.377 s
T90_error 0.979 s
T90_start 1:59:04.691 UTC
fluence 8.72e-06 erg/cm²
fluence_error 8.20e-08 erg/cm²
flux_1024 8.33e+00 erg/cm²/s
flux_1024_error 2.21e-01 erg/cm²/s
flux_1024_time 9.73e+00 erg/cm²/s
flux_64 1.01e+01 erg/cm²/s
flux_64_error 9.57e-01 erg/cm²/s
IPN table
GRB_name GRB100615A
ra 177.2083°
decl -19.5000°
pos_error 5.00e-02°
redshift 1.3980
Swift table
GRB_name GRB100615A
t_trigger 1:59:03 UTC
ra 177.2054°
decl -19.4812°
pos_error 1.81e-04°
T90 39.0 s
fluence 5.00e-06 erg/cm²
redshift 1.3980
GCN 10841 table
GRB_name GRB100615A
GCN_number 10841
Detection_method Swift Det
t_trigger 1:59:03 UTC
ra 177.2070°
decl -19.4960°
Circular_text TITLE: GCN CIRCULAR NUMBER: 10841 SUBJECT: GRB 100615A: Swift detection of a burst DATE: 10/06/15 02:13:23 GMT FROM: Scott Barthelmy at NASA/GSFC V. D'Elia (ASDC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC), C. B. Markwardt (CRESST/GSFC/UMD), T. Sakamoto (NASA/UMBC), M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC), G. Stratta (ASDC), T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the Swift Team: At 01:59:03 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 100615A (trigger=424733). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 177.207, -19.496 which is RA(J2000) = 11h 48m 50s Dec(J2000) = -19d 29' 45" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows 3 strong peaks with a duration of about 60 sec. The peak count rate was ~7000 counts/sec (15-350 keV), at ~5 sec after the trigger. The XRT began observing the field at 02:00:06.4 UT, 62.4 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 177.20376, -19.48169 which is equivalent to: RA(J2000) = 11h 48m 48.90s Dec(J2000) = -19d 28' 54.1" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 52 arcseconds from the BAT onboard position, within the BAT error circle. 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 (3.28e+20 cm^-2, Kalberla et al. 2005), with an excess column of 1.3 (+0.47/-0.39) x 10^22 cm^-2 (90% confidence). The initial flux in the 2.5 s image was 6.15e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 71 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 0.05. Burst Advocate for this burst is V. D'Elia (delia AT asdc.asi.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 10842 table
GRB_name GRB100615A
GCN_number 10842
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 10842 SUBJECT: GRB 100615A: NTT/Ultracam imaging DATE: 10/06/15 04:14:30 GMT FROM: Nial Tanvir at IofA U.Cambridge V. Dhillon (U. Sheffield), R. Mignani (MSSL), S. Schulze (U. Iceland), A. J. Levan (U. Warwick), N. R. Tanvir (U. Leicester), A. de Cia (U. Iceland) report on behalf of the ULTRACAM collaboration: We observed the field of GRB 100615A (D'Elia et al., GCN 10841) with ULTRACAM (Dhillon et al., MNRAS, 2007, 378, 825) mounted on the 3.5-m NTT telescope on La Silla, beginning approximately 17 mins post-burst. Stacking the images from 02:16:27 to 02:39:29 UT did not reveal any new source down to 24 mag (3 sigma) in the i' band. The deep limiting magnitude at early times, coupled with bright X-ray afterglow with moderate hydrogen column density (D'Elia et al. GCN 10841) is suggestive of a highly extinguished burst.
GCN 10843 table
GRB_name GRB100615A
GCN_number 10843
Detection_method correction
Circular_text TITLE: GCN CIRCULAR NUMBER: 10843 SUBJECT: GRB 100615A: PAIRITEL NIR Upper Limits DATE: 10/06/15 05:41:52 GMT FROM: Adam Morgan at U.C. Berkeley A. N. Morgan C. R. Klein, and J. S. Bloom (UC Berkeley) report: We observed the field of GRB 100615A (D'Elia et al., GCN 10841) with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began at 2010-06-15 03h21m51 UT, ~1.4 hours after the Swift Trigger, under high airmass (~2), and continued until the source set beyond telescope limits. In mosaics (effective exposure time of 0.56 hours) taken simultaneously in the J, H, and Ks filters, we do not detect any source within the XRT error circle. The preliminary photometry yields: post burst t_mid (hr) exp.(hr) filt U. Limit (3 sig) 1.94 0.56 J > 18.8 1.94 0.56 H > 17.9 1.94 0.56 Ks > 16.6 All magnitudes are given in the Vega system, calibrated to 2MASS. No correction for Galactic extinction has been made to the above reported values.
GCN 10844 table
GRB_name GRB100615A
GCN_number 10844
Detection_method GROND
Circular_text TITLE: GCN CIRCULAR NUMBER: 10844 SUBJECT: GRB 100615A: GROND observations, upper limits DATE: 10/06/15 05:47:41 GMT FROM: Sylvio Klose at TLS Tautenburg A. Nicuesa, S. Klose (both TLS Tautenburg), and J. Greiner (MPE Garching), report on behalf of the GROND team: GROND (Greiner et al. 2008, PASP 120, 405), the 7-channel imager mounted at the 2.2m ESO/MPI telescope on La Silla, started follow-up observations of GRB 100615A (D'Elia et al. 2010, GCN 10841) on June 15 at 2:05 UT (about 6 min after the trigger). Within the 3.7 arcsec XRT error circle we do not find any afterglow candidate. Preliminary measured upper limits based on an 8 min observing block starting at 2:20 UT are (in the AB system, 3 sigma): g' > 24.2, r' > 23.9, i' > 22.9, z' > 22.5, J > 21.4, H > 20.7, K > 20.3, using GROND zeropoints and the 2MASS catalog. This is in agreement with the report by Dhillon et al. about the non-detection in the i' band (GCN 10842).
GCN 10847 table
GRB_name GRB100615A
GCN_number 10847
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 10847 SUBJECT: GRB 100615A: Swift-XRT refined analysis DATE: 10/06/15 10:02:44 GMT FROM: Raffaella Margutti at U. di Milano Bicocca R. Margutti, B. Sbarufatti (INAF-OAB) and V. D'Elia (ASDC) report on behalf of the Swift-XRT team: We have analysed 1.1 ks of XRT data for GRB 100615A (D'Elia et al. GCN Circ. 10841), from 68 s to 1.2 ks after the BAT trigger. The data comprise 73 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The light curve can be modelled with an initial power-law decay with an index of alpha=4.17 (+0.23, -0.22), followed by a break at T+191 s to an alpha of -0.03 (+0.23, -0.25). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.21 (+0.16, -0.15). The best-fitting absorption column is 8.8 (+1.1, -1.0) x 10^21 cm^-2, in excess of the Galactic value of 3.3 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 2.6 (+0.4, -0.3) and a best-fitting absorption column of 1.18 (+0.29, -0.25) x 10^22 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.9 x 10^-11 (1.9 x 10^-10) erg cm^-2 count^-1. If the light curve continues to decay with a power-law decay index of -0.03, the count rate at T+24 hours will be 1.4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.8 x 10^-11 (2.6 x 10^-10) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00424733. This circular is an official product of the Swift-XRT team.
GCN 10848 table
GRB_name GRB100615A
GCN_number 10848
Detection_method Swift-XRT Det
ra 177.2052°
decl -19.4812°
Circular_text TITLE: GCN CIRCULAR NUMBER: 10848 SUBJECT: GRB 100615A: Enhanced Swift-XRT position DATE: 10/06/15 10:21:14 GMT FROM: Phil Evans at U of Leicester M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 1489 s of XRT Photon Counting mode data and 2 UVOT images for GRB 100615A, 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 = 177.20522, -19.48118 which is equivalent to: RA (J2000): 11h 48m 49.25s Dec (J2000): -19d 28' 52.2" 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.
GCN 10850 table
GRB_name GRB100615A
GCN_number 10850
Detection_method Swift-BAT Det
ra 177.2080°
decl -19.4830°
Circular_text TITLE: GCN CIRCULAR NUMBER: 10850 SUBJECT: GRB 100615A: Swift-BAT refined analysis DATE: 10/06/15 11:59:42 GMT FROM: Scott Barthelmy at NASA/GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), V. D'Elia (ASDC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-61 to T+242 sec from recent telemetry downlinks, we report further analysis of BAT GRB 100615A (trigger #424733) (D'Elia, et al., GCN Circ. 10841). The BAT ground-calculated position is RA, Dec = 177.208, -19.483 deg, which is RA(J2000) = 11h 48m 49.9s Dec(J2000) = -19d 29' 00.0" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 99%. The mask-weighted light curve shows 3 slightly overlapping FRED peaks with the first starting at ~T-0.2 sec and peaking at ~T+2 sec. The second peaks at ~T+10 sec. The third peaks at ~T+30 sec and ends at ~T+~120 sec. T90 (15-350 keV) is 39 +- 2 sec (estimated error including systematics). The time-averaged spectrum from T-0.0 to T+47.4 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.87 +- 0.04. The fluence in the 15-150 keV band is 5.0 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+10.26 sec in the 15-150 keV band is 5.4 +- 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/424733/BA/
GCN 10851 table
GRB_name GRB100615A
GCN_number 10851
Detection_method Fermi GBM Det
t_trigger 1:59:04.370 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 10851 SUBJECT: GRB 100615A: Fermi GBM detection DATE: 10/06/15 13:47:12 GMT FROM: Suzanne Foley at MPE S. Foley (MPE) and M. Briggs (UAH) report on behalf of the Fermi GBM Team: "At 01:59:04.37 UT on 15 June 2010, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 100615A (trigger 298259946 / 100615083) which was also detected by the SWIFT-BAT (D'Elia et al. 2010, GCN 10841). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 64 degrees. The GBM light curve consists of 3 main pulses with a duration (T90) of about 37.7 +/- 0.8 s (10-1000 keV). The time-averaged spectrum from T0+0.003 s to T0+39.553 s is best fit by a power law function with an exponential high energy cutoff. The power law index is -1.34 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 106.20 (+7.53/-6.07) keV (CSTAT 989.31 for 606 d.o.f.). The event fluence (8-1000 keV) in this time interval is (8.64 +/- 0.17)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+9.7 s in the 8-1000 keV band is 8.3 +/- 0.2 ph/s/cm^2. A Band function fits the spectrum equally well (CSTAT 976.41 for 605 d.o.f.) with Epeak = 85.73 (+7.82/-9.33) keV, alpha = -1.24 (+0.08/-0.06) and beta = -2.27 (+0.11/-0.12). The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN 10856 table
GRB_name GRB100615A
GCN_number 10856
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 10856 SUBJECT: GRB 100615A: Swift/UVOT Upper Limits DATE: 10/06/15 19:21:44 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/GSFC/USRA) and V. D'Elia (ASDC) report on the behalf of the Swift UVOT team: The Swift/UVOT observed the field of GRB 100615A starting 53 s after the BAT trigger (D'Elia, et al., 2010, GCN Circ. 10841). Settled observations started at 72 s. We do not find any new source, relative to the DSS, USNO-B1.0, or 2MASS at the position of the XRT afterglow (Goad, et al. 2010, GCN Circ. 10848). Preliminary 3-sigma upper limits for detecting a source in the finding charts, and in the co-added images, using a 2.5 arcsecond radius circular aperture, are Filter T_start T_stop Exp(s) Mag -------------------------------------------- white (fc) 72 222 147 >21.5 864 1014 147 >21.5 u (fc) 284 534 246 >20.7 v 613 7037 510 >20.6 b 539 6422 490 >21.1 u 284 6216 539 >21.1 uvw1 663 7436 499 >21.1 uvm2 813 7242 413 >20.7 uvw2 589 6832 471 >21.1 white 72 6627 785 >22.2 -------------------------------------------- The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E_{B-V} = 0.05 mag (Schlegel, et al., 1998, ApJS, 500, 525). All photometry is on the UVOT photometry system described in Poole et al. (2008, MNRAS, 383, 627).
GCN 10858 table
GRB_name GRB100615A
GCN_number 10858
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 10858 SUBJECT: GRB 100615A: Swift/UVOT Upper Limits DATE: 10/06/15 19:32:42 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/GSFC/USRA) and V. D'Elia (ASDC) report on the behalf of the Swift UVOT team: The Swift/UVOT observed the field of GRB 100615A starting 53 s after the BAT trigger (D'Elia, et al., 2010, GCN Circ. 10841). Settled observations started at 72 s. We do not find any new source, relative to the DSS, USNO-B1.0, or 2MASS at the position of the XRT afterglow (Goad, et al. 2010, GCN Circ. 10848). Preliminary 3-sigma upper limits for detecting a source in the finding charts, and in the co-added images, using a 2.5 arcsecond radius circular aperture, are Filter T_start T_stop Exp(s) Mag -------------------------------------------- white (fc) 72 222 147 >21.5 864 1014 147 >21.5 u (fc) 284 534 246 >20.7 v 613 7037 510 >20.6 b 539 6422 490 >21.1 u 284 6216 539 >21.1 uvw1 663 7436 499 >21.1 uvm2 813 7242 413 >20.7 uvw2 589 6832 471 >21.1 white 72 6627 785 >22.2 -------------------------------------------- The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E_{B-V} = 0.05 mag (Schlegel, et al., 1998, ApJS, 500, 525). All photometry is on the UVOT photometry system described in Poole et al. (2008, MNRAS, 383, 627). [GCN OPS NOTE(08mar13): This is a duplicate submission of 10856. Acknowledgement to F.Marshall for pointing this out.]
GCN 10861 table
GRB_name GRB100615A
GCN_number 10861
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 10861 SUBJECT: GRB 100615A: Gemini/NIRI Observations DATE: 10/06/16 17:04:00 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko, D. A. Perley (UC Berkeley), N. R. Tanvir (U. Leicester), A. J. Levan (U. Warwick), J. S. Bloom, B. E. Cobb (UC Berkeley), K. Wiersema (U. Leicester) report on behalf of a larger collaboration: We have imaged the field of GRB100615A (D'Elia et al., GCN 10841) with the Near InfraRed Imager on the 8-m Gemini North telescope. Observations were obtained in the J and K filters beginning at 7:36 UT on 15 June 2010 (~ 5.5 hours after the trigger). We find no sources inside the revised XRT error circle (Goad et al., GCN 10848) to limiting magnitudes of J > 22.1, K > 20.9 (Vega, calibrated with respect to 2MASS). Combined with additional limits from other facilities (Dhillon et al., GCN 10842; Morgan et al., GCN 10843; Nicuesa et al., GCN 10844; Holland and D'Elia, GCN 10856), and the large excess X-ray column derived from XRT observations (Margutti et al., GCN 10847), we conclude that GRB100615A is likely a highly extinguished event.
GCN 10915 table
GRB_name GRB100615A
GCN_number 10915
Detection_method Optical
ra 177.2056°
decl -19.4811°
Circular_text TITLE: GCN CIRCULAR NUMBER: 10915 SUBJECT: GRB 100615A: Chandra X-ray ToO Observation DATE: 10/07/01 20:58:13 GMT FROM: Nat Butler at UC berkeley N. R. Butler, D. A. Perley, S. B. Cenko, J. S. Bloom (UC Berkeley), A. J. Levan (U. Warwick), and N. R. Tanvir (U. Leicester) report on behalf of a larger collaboration: Beginning 2010/06/15 01:59 UT (6.1 days post burst) and for a period of 14.8 ksec (livetime), Chandra targeted the field of the optically dark GRB 100615A (D'Elia et al. 2010, GCN 10841; Foley et al. 2010, GCN 10851) with ACIS-S under Director's Discretionary Time. The X-ray afterglow is well detected (210 cts, 0.5-8 keV) at a position consistent with that of the Swift GRB and afterglow (GCN 10841; Goad et al. 2010, GCN 10848). We find: RA, Dec (J2000) = 11:48:49.34, -19:28:52.0 +/- 0.6" The counts spectrum can be modelled by an absorbed powerlaw, with photon index Gamma = 2.0+/-0.5 (Cash/nu = 11.2/17). The unabsorbed flux is 3.2^{+1.4}_{-0.7} x 10^{-13} erg cm^(-2) s^(-1) (0.5-8 keV). There is 6-sigma significant evidence (Delta Cash = 32.4 for 1 additional degree of freedom) for a large N_H column 1.0^{+0.4}_{-0.3} x 10^22 cm^(-2) (z=0) in excess of the Galactic value (3.3 x10^20 cm^(-2); Kalberla et al. 2005). This is in agreement with the XRT analyses (Margutti et al. 2010, GCN 10847) and further indicates that GRB 100615A is likely a highly extinguished event (see also, Cenko et al. 2010, GCN 10861). All uncertainties above are 90% confidence. We thank Harvey Tananbaum and the CXO team for permitting and rapidly conducting this observation. This message can be cited.
GCN 10928 table
GRB_name GRB100615A
GCN_number 10928
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 10928 SUBJECT: GRB 100615A: Additional Gemini/NIRI observations DATE: 10/07/02 22:58:46 GMT FROM: Daniel Perley at U.C. Berkeley D. A. Perley, J. S. Bloom, S. B. Cenko, and N. R. Butler (UC Berkeley) report: We again observed the field of GRB 100615A (D'Elia et al. 2010, GCN 10841) using NIRI on Gemini-North between 06:06 and 07:03 on 2010-06-24 UT, at moderately high airmass. We acquired 45 images of 60 seconds each in the K' filter, a significantly deeper integration than our previous observation (Cenko et al., GCN 10861). A faint object is detected slightly west of the latest online UVOT-enhanced XRT error circle, with an aperture magnitude of K' = 21.3 +/- 0.3 mag. However, the location of this object is not consistent with the improved X-ray localization provided by the Chandra observations (Butler et al., GCN 10915). A very faint possible source is visible at the Chandra location, but it is not statistically significant (1.5-sigma). The 3-sigma limit of the image is K' > 22.2 mag; forced photometry gives K' = 23.0 +/- 0.8 mag at this location. An image of the field is posted to: http://lyra.berkeley.edu/~dperley/100615a/100615a_niri.png
GCN 14264 table
GRB_name GRB100615A
GCN_number 14264
Detection_method Swift-XRT Other
ra 177.2056°
decl -19.4811°
redshift 1.3980
Circular_text TITLE: GCN CIRCULAR NUMBER: 14264 SUBJECT: GRB 100615A: HST host detection and X-shooter redshift DATE: 13/03/06 17:46:42 GMT FROM: Thomas Kruehler at Dark Cosmology Center T. Kruehler, D. Malesani, D. Xu, J. P. U. Fynbo (DARK/NBI), A. J. Levan (U. Warwick), N. R. Tanvir (U. Leicester), V. D'Elia (ASDC, INAF) and D. Perley (Caltech) report on behalf of the X-shooter GTO GRB collaboration: The field of GRB 100615A (Swift trigger 424733, D'Elia et al., GCN 10841) was observed with the Hubble Space Telescope and WFC3 (filters F606W and F160W) under proposal ID 11840 (PI: A. J. Levan). Observations were carried out on 2010 Dec 16 (154 days after the GRB), for a total exposure time of 1128 s and 1208 s, respectively. In the HST images, we detect a single, resolved object (F160W = 24.1 AB mag) consistent with the Chandra X-ray position (Butler et al., GCN 10915), which we consider to be the GRB host galaxy. Its coordinates are (J2000): RA = 11:48:49.34 Dec = -19:28:51.8 A spectrum of this source was taken on 2013 Mar 05 with the ESO VLT equipped with the X-shooter spectrograph, covering the wavelength range 3000-20500 AA. The seeing was 0.8". In the VIS and NIR arm, we detect several emission lines, interpreted as the doublet of [O II](3726, 3729), [Ne III](3869), [O III](4959), [O III](5007) and Halpha at a common redshift of z = 1.398. At this redshift, the afterglow data imply a very high host exinction along the GRB sight-line (A_V > 10-15, see D'Elia & Stratta 2011, A&A, 532, A48, their Figure 4). The intrinsic soft X-ray absorption column measured from Swift/XRT data (Margutti et al., GCN 10847) at z = 1.398 is N_{H,X} = 1.07 (+0.13, -0.12) x 10^23 cm^-2. This is similarly at the high end of measured column densities, even among dark bursts (e.g., Kruehler et al., 2012, ApJ, 758, 46, their Figure 5). In contrast, the host of GRB 100615A is rather blue (F606W - F160W \sim 1 AB mag) and does not show obvious signs of heavy dust content. We acknowledge excellent support from the observing staff at Paranal, in particular Giacomo Beccari and Emanuela Pompei.