//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10361 SUBJECT: GRB 100205A: Swift detection of a burst DATE: 10/02/05 04:34:16 GMT FROM: David Palmer at LANL J. L. Racusin (NASA/GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), P. A. Evans (U Leicester), E. A. Hoversten (PSU), J. A. Kennea (PSU), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC), R. L. C. Starling (U Leicester), T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the Swift Team: At 04:18:43 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 100205A (trigger=411248). Swift slewed immediately to the burst. The BAT on-board calculated location is RA 141.406d, Dec +31.739d, which is RA(J2000) = 09h 25m 37s Dec(J2000) = +31d 44' 22" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 30 sec. The peak count rate was ~800 counts/sec (15-350 keV), at ~8 sec after the trigger. The XRT began observing the field at 04:21:38.0 UT, 174.9 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 141.3874, 31.7405 which is equivalent to: RA(J2000) = 09h 25m 32.99s Dec(J2000) = +31d 44' 25.8" with an uncertainty of 2.2 arcseconds (radius, 90% containment). This location is 57 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 consistent with the Galactic value of 1.65e+20 cm^-2 (Kalberla et al. 2005). UVOT took a finding chart exposure of 150 seconds with the White filter starting 177 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 J. L. Racusin (judith.racusin 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.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10362 SUBJECT: GRB 100205A: NOT optical observations DATE: 10/02/05 06:01:21 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst D. Malesani (DARK/NBI), D. Xu (WIS and DARK/NBI), J. P. U. Fynbo (DARK/NBI), P. Jakobsson (Univ. Iceland), N. R. Tanvir (Univ. Leicester), J. Lindberg (NOT and Univ. Copenhagen), report on behalf of a larger collaboration: We observed the field of GRB 100205A (Racusin et al., GCN 10361) with the NOT equipped with ALFOSC. Observations were carried out in the R and I bands, starting at 4:58 and 5:16 UT, that is 39 and 58 min after the GRB, respectively. Within the XRT error circle, we do not detect any new source down to limiting magnitudes R > 23.7 and I > 23.2 (assuming R=17.3 and I = 16.8 for the object at RA = 09:25:28.94, Dec = +31:44:20.8). We encourage NIR observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10364 SUBJECT: GRB 100205A: Super-LOTIS early observations DATE: 10/02/05 06:20:25 GMT FROM: Adria C. Updike at Clemson U Adria C. Updike (Clemson University), G. Grant Williams (MMTO), Peter A. Milne (Steward Observatory), and Dieter H. Hartmann (Clemson University) report: We observed the field of GRB 100205A (Racusin et al., GCN 10361) with the 0.6m Super-LOTIS telescope located at KPNO under poor conditions. Observations began 110 seconds after the trigger and continued for 7 minutes before we were forced to close due to humidity. In 270 seconds of stacked V-band exposures, we detect no new sources in the XRT error circle down to a limiting magnitude V > 18 (upon comparison to the NOMAD catalog), which is consistent with the NOT observations (Malesani et al., GCN 10362). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10365 SUBJECT: GRB 100205A: Gemini-South Observations DATE: 10/02/05 08:13:43 GMT FROM: Bethany Cobb at UC Berkeley B. E. Cobb, S. B. Cenko, J. S. Bloom (UC Berkeley) report on behalf of a larger collaboration: We have imaged the field of GRB 100205A (Racusin et al., GCN 10361) with the Gemini Multi-Object Spectrograph (GMOS) on the 8 m Gemini South telescope beginning at 05:48 UT on 05 February 2010 (~ 40 minutes after the burst trigger time). Observations were conducted in the r' filter for a total of 600 seconds. We find no new point sources at the location of the X-ray afterglow (Racusin et al., GCN 10361). The preliminary limiting magnitude of our image is r' >~ 23.4 mag for isolated point sources (assuming the SDSS value of r = 17.76 for the object at RA: 09:25:28.956, Dec: +31:44:20.61). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10366 SUBJECT: GRB 100205A Gemini-North IR afterglow candidate DATE: 10/02/05 12:24:45 GMT FROM: Nial Tanvir at IofA U.Cambridge N. R. Tanvir (U. Leicester), A. J. Levan (U. Warwick), A. Cucchiara & D. Fox (PSU), B. E. Cobb (UC Berkeley), R. Mason (Gemini) report on behalf of a larger collaboration: We observed the field of GRB 100205A (Racusin et al. GCN 10361) with Gemini-North/NIRI, beginning at 06:55 UT (approx 2.6 hr post burst). In a deep K-band integration we detect a point source within the enhanced XRT error circle, at position (accuracy ~0.5 arcsec): RA(2000) = 09 25 33.02 dec(2000)= +31 44 25.0 The approximate magnitude (calibrated against two faint 2MASS stars in the field) is K~20.2. The source is also marginally detected in both J and H. Further analysis is ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10367 SUBJECT: GRB 100205A: Enhanced Swift-XRT position DATE: 10/02/05 14:00:10 GMT FROM: Phil Evans at U of Leicester P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 1394 s of XRT Photon Counting mode data and 2 UVOT images for GRB 100205A, 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 = 141.38751, +31.74050 which is equivalent to: RA (J2000): 09h 25m 33.00s Dec (J2000): +31d 44' 25.8" 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: 10369 SUBJECT: GRB 100205A: Swift XRT refined analysis DATE: 10/02/05 16:47:28 GMT FROM: Rhaana Starling at U of Leicester R.L.C. Starling (U Leicester) and J.L. Racusin (NASA/GSFC) report on behalf of the Swift-XRT team: We have analysed 1.5 ks of XRT data for GRB 100205A (trigger=411248, Racusin et al. GCN Circ. 10361), from 157 s to 4.95 ks after the BAT trigger. The data comprise 11 s of Windowed Timing (WT) mode settling data and the remainder is in Photon Counting (PC) mode. At this point Swift coverage of the source stopped due to thermal constraints, but further observations are now underway. The enhanced XRT position is given in Evans et al. GCN Circ. 10367. The light curve can be fit with a doubly broken power law. The difference between the initial WT mode settling data and the first PC data suggest a steep initial decay of alpha~9.5. This power law decay breaks at ~180 s to a plateau with alpha~-0.05, which breaks at 330 +140/-60 s to a decay of alpha = 2.5 +0.4/-0.3. The time-averaged PC mode spectrum can be fit with an absorbed power law of photon index Gamma = 2.2 +/-0.3, and absorption column N_H (intrinsic at z=0) = (7 +6/-5) x 10^20 cm^-2 in excess of the Galactic column of 1.65 x 10^20 cm^-2 (Kalberla et al. 2005). The observed (unabsorbed) 0.3-10 keV flux is (9.0 +1.6/-2.0) x 10^-12 (1.2 x 10^-11) erg cm^-2 s^-1. The observed (unabsorbed) counts to flux conversion is 3.7 x 10^-11 (4.9 x 10^-11) erg cm^-2 ct^-1. If the light curve continues to decay with alpha = 2.5 the predicted count rate at T+24h is 1 x 10^-6 ct s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00411248. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10370 SUBJECT: GRB 100205A: Swift UVOT upper limits DATE: 10/02/05 17:37:38 GMT FROM: Erik Hoversten at Swift/Penn State E. A. Hoversten (PSU) and J. L. Racusin (NASA/GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 100205A 177s after the BAT trigger (Racusin et al., GCN 10361). We do not detect any source at the enhanced Swift XRT position (Racusin et al., GCN 10361) nor at the position of the Gemini-North K-band detection (Tanvir et al., GCN 10366). UVOT magnitude 3-sigma upper limits are reported in the following table: Filter T_start T_stop Exp(s) Mag (3-sigma upper limit) ------------------------------------------------------------- white 177 327 147 > 20.76 white 177 1533 392 > 21.31 v 665 1580 94 > 18.84 b 763 1162 38 > 19.25 u 335 1311 265 > 20.08 The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight of E_(B-V) = 0.02 mag (Schlegel et al. 1998). All photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10371 SUBJECT: GRB 100205A: Swift-BAT refined analysis DATE: 10/02/05 18:16:34 GMT FROM: Scott Barthelmy at NASA/GSFC T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (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 100205 (trigger #411248) (Racusin, et al., GCN Circ. 10361). The BAT ground-calculated position is RA, Dec = 141.385, 31.740 deg which is RA(J2000) = 09h 25m 32.5s Dec(J2000) = +31d 44' 23.7" with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 80%. The mask-weighted light curve shows a roughly symetric peak starting at ~T-15 sec, peaking at ~T+5 sec, and ending at ~T+30 sec. T90 (15-350 keV) is 26.0 +- 8 sec (estimated error including systematics). The time-averaged spectrum from T-12.6 to T+25.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.60 +- 0.25. The fluence in the 15-150 keV band is 4.0 +- 0.7 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+8.12 sec in the 15-150 keV band is 0.4 +- 0.1 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/411248/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10374 SUBJECT: GRB 100205A: Gemini-N + NIRI photometry DATE: 10/02/05 21:18:42 GMT FROM: Antonino Cucchiara at PSU A. Cucchiara (PSU), D. B. Fox (PSU), N. R. Tanvir (U. Leicester), A. J. Levan (U. Warwick), B. E. Cobb (UC Berkeley), E. Berger (Harvard/CfA), and R. Chornock (Harvard/CfA) report on behalf of a larger collaboration: We have calibrated the JHK photometry for the candidate Gemini-N + NIRI afterglow (Tanvir et al., GCN 10366) of GRB 100205A (Racusin et al., GCN 10361) against two 2MASS stars in the field. Converted to AB magnitudes we find: J_AB > 23.37 mag (1-sigma UL) H_AB = 23:54 +- 0.22 mag K_AB = 21.91 +- 0.20 mag Thus, based on our photometry we measure a red K-H color, K_AB - H_AB = 1.6 +- 0.5 mag. If this red color is due to Lyman-alpha absorption within the H filter bandpass, then this would imply a redshift of 11 <~ z <~ 13.5. In this connection, we note that we are retracting our earlier claim of a J-band detection (Tanvir et al., GCN 10366) at the candidate position. Lower-redshift solutions with significant local (host) extinction, unusual afterglow colors, or substantial contributions from an underlying host galaxy cannot be excluded at this time. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10375 SUBJECT: GRB100205A: CFHT z'-band observation DATE: 10/02/06 13:41:45 GMT FROM: Yuji Urata at Nat. Central U. Y.Urata (NCU), K.Y. Huang (ASIAA), M. Im (SNU) report on behalf of EAFON: "We have imaged the field of GRB100205A (Racusin et al. GCN 10361) using CFHT. The observation was started at 7:11UT on Feb. 6 (about 26.9 hr after the burst). The z'-band stacked image shows no source at the position of the NIR afterglow (Tanvir et al. GCN 10366) down to z'~24.5." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10383 SUBJECT: GRB 100205A: GROND upper limits DATE: 10/02/06 20:58:37 GMT FROM: Ana Nicuesa at TLS Tautenburg A. Nicuesa (Tautenburg Obs.), T. Kruehler (MPE), A. Rossi (Tautenburg Obs.) and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the field of GRB 100205A (Swift trigger #411248; Racusin et al., GCN #10361) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at LaSilla Observatory (Chile). Due to cloud coverage, observations started only on 05 Feb. 2010 at 06:37:58 UT, 2.3 h after the burst, and were severely affected by passing cirrus. In stacked images with a total integration time of 12 minutes in JHK and 13 minutes in g'r'i'z' we do not detect the NIR afterglow candidate reported by Tanvir et al. (GCN #10366) down to the following limits, all in the AB system: g' > 22.8, r' > 23.0, i' > 22.4, z' > 22.2, J > 21.0, H > 20.6 and K > 20.3 These upper limits have been obtained using SDSS and 2MASS field stars as reference, and are consistent with the magnitudes reported by Cucchiara et al. (GCN #10374). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10398 SUBJECT: GRB 100205A: BOAO/LOAO zYJK observation DATE: 10/02/09 14:50:50 GMT FROM: Myungshin Im at Seoul Nat U M. Im, Y. Jeon, W. Park (CEOU/Seoul National Univ), H.-I. Sung (KASI) and Y. Urata (NCU) on behalf of EAFON team. We observed the GRB100205A (GCN 10361 Racusin et al.) with J and K-band using KASINICS instrument on the 1.8m telescope at the Bohyunsan Optical Astronomy Observatory (BOAO), Korea, starting from 2010-02-05, 17:28:13 UT. We also observed the GRB with z and Y filters using the LOAO 1-m telescope, starting from 2010-02-05, 10:37:51 UT. We do not detect the afterglow at the reported position (GCN 10361.; GCN 10366, Tanvir et al.) in any of the bands with the upper limits summarized below. Our non-detection in K suggests that the afterglow candidate faded since the report of the K-band detection (GCN 10366; GCN 10374 Cucchiara et al.), confirming that it is an afterglow. The values for J and K-bands are preliminary, and we are refining the photometry. The data analysis of the 2nd night follow-up observation (z,Y) is on-going. Filter z Y J K ------------------------------------------------- 3-sigma limit (AB) 22.3 20.8 22.3 22.5 mid-point(UT,hh:mm) 12:11 11:07 17:43 19:01 We thank the LOAO operator, J. Yoon for his assistance for this observation. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10399 SUBJECT: GRB 100205A: Keck limits on an underlying host galaxy DATE: 10/02/10 13:06:10 GMT FROM: Daniel Perley at U.C. Berkeley D. A. Perley, J. S. Bloom, S. B. Cenko, B. E. Cobb, A. N. Morgan, A. A. Miller, and C. R. Klein (UC Berkeley) report: We conducted a deep optical imaging integration on the field of GRB 100205A (Racusin et al., GCN 10361) using LRIS on the Keck I 10m telescope starting at 09:48 UT on 2010 Feb 7. We integrated for a total exposure time of 4000 seconds in g-band and 3770 seconds in R-band simultaneously under clear skies but variable and generally poor seeing conditions (1.5 arcsec average). The mid-point of the integration was at 10:28 UT. We detect no source at the position of the putative infrared afterglow (Tanvir et al., GCN 10366). Calibrating relative to USNOB1.0, we measure limiting magnitudes (3-sigma) of: R > 26.7 g > 26.6 as measured at the afterglow location. A faint source is marginally detected (<2 sigma) in R-band only at the northwestern edge of the XRT error circle (Evans et al., GCN 10367), not consistent with the position of the infrared afterglow. We also stacked the R-band and g-band images together to create a white-light composite image. There is no significant detection in this image, with an approximate limiting magnitude of White > 27 mag. All properties of this GRB are consistent with it being at high redshift: * Lack of optical detection starting at early times (e.g. Malesani et al., GCN 10362; Updike et al., GCN 10364; Cobb et al, GCN 10365) * An apparently fading afterglow candidate detected only in H- and K-bands (Cucchiara et al., GCN 10374; Im et al., GCN 10398) * Limited X-ray absorption: excess N_H(z=0) = 7(+6/-5) x 10^20 cm^-2 (Starling and Racusin, GCN 10369), generally suggestive of higher redshift (Grupe et al. 2007, AJ 133:2216G) and inconsistent with the alternative hypothesis of a large extinction column at low redshift for typical values of A_V/N_H. * Lack of host galaxy to deep limits (Perley et al. 2009, AJ 138:1690) As mentioned by Cucchiara et al., the implied redshift of this GRB if the red H-K color is due to Lyman-alpha absorption would be z ~ 11-13. However, significant dust absorption at intermediate redshift (e.g., A_V~3 mag at z~4) is still generally consistent with the available data, and unfortunately the X-ray afterglow is too faint to impose meaningful constraints on extinction in the K-band during the Gemini observation. An image of the field is posted to: http://lyra.berkeley.edu/~dperley/100205a/100205a_keck_gR.png We encourage continued deep infrared follow-up of the field.