GRB141221A

This page lists all entries on GRB141221A in GRBweb

Summary Fermi GBM IPN Swift GCN 17206 GCN 17208 GCN 17209 GCN 17210 GCN 17211 GCN 17212 GCN 17213 GCN 17214 GCN 17216 GCN 17219 GCN 17221 GCN 17222 GCN 17227 GCN 17228

Summary table
Variable Value Source
GRB_name_Fermi GRB141221338
T0 8:07:02.512 UTC Fermi_GBM
ra 198.2867° Swift
decl 8.2052° Swift
pos_error 5.57e-05° Swift
T90 23.808 s Fermi_GBM
T90_error 1.717 s Fermi_GBM
T90_start 8:07:02.512 UTC Fermi_GBM
fluence 4.07e-06 erg/cm² Fermi_GBM
fluence_error 6.28e-08 erg/cm² Fermi_GBM
redshift 1.4520
T100 44.388 s
GBM_located False
mjd 57012.33822351852 Fermi_GBM
Fermi GBM table
GRB_name_Fermi GRB141221338
trigger_name bn141221338
ra 198.2858°
decl 8.2053°
pos_error 4.60e+00°
datum 2014-12-21
t_trigger 8:07:11.216 UTC
T90 23.808 s
T90_error 1.717 s
T90_start 8:07:02.512 UTC
fluence 4.07e-06 erg/cm²
fluence_error 6.28e-08 erg/cm²
flux_1024 5.38e+00 erg/cm²/s
flux_1024_error 3.45e-01 erg/cm²/s
flux_1024_time -1.92e-01 erg/cm²/s
flux_64 8.94e+00 erg/cm²/s
flux_64_error 1.52e+00 erg/cm²/s
IPN table
GRB_name GRB141221A
ra 198.2708°
decl 8.2167°
pos_error 5.00e-02°
redshift 1.4520
Swift table
GRB_name GRB141221A
t_trigger 8:07:10 UTC
ra 198.2867°
decl 8.2052°
pos_error 5.57e-05°
T90 36.9 s
fluence 2.10e-06 erg/cm²
redshift 1.4520
GCN 17206 table
GRB_name GRB141221A
GCN_number 17206
Detection_method Swift Det
t_trigger 8:07:10 UTC
ra 198.2690°
decl 8.2100°
Circular_text TITLE: GCN CIRCULAR NUMBER: 17206 SUBJECT: GRB 141221A: Swift detection of a burst with an optical counterpart DATE: 14/12/21 08:21:02 GMT FROM: Kim Page at U.of Leicester E. Sonbas (NASA/GSFC/Adiyaman Univ.), J. R. Cummings (NASA/UMBC), V. D'Elia (ASDC), L. Izzo (URoma/ICRA), A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 08:07:10 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 141221A (trigger=622006). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 198.269, +8.210 which is RA(J2000) = 13h 13m 05s Dec(J2000) = +08d 12' 36" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with a duration of about 20 sec. The peak count rate was ~4000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 08:08:30.3 UT, 79.5 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 198.28642, 8.20536 which is equivalent to: RA(J2000) = 13h 13m 08.74s Dec(J2000) = +08d 12' 19.3" with an uncertainty of 3.9 arcseconds (radius, 90% containment). This location is 64 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 (2.27 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.5 (+2.80/-2.41) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 83 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 13:13:08.80 = 198.28666 DEC(J2000) = +08:12:18.8 = 8.20523 with a 90%-confidence error radius of about 0.61 arc sec. This position is 4.2 arc sec. from the center of the XRT error circle. The estimated magnitude is 17.18 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.03. Burst Advocate for this burst is E. Sonbas (edasonbas AT yahoo.com). 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 17208 table
GRB_name GRB141221A
GCN_number 17208
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 17208 SUBJECT: GRB141221A: REM afterglow DATE: 14/12/21 15:01:52 GMT FROM: Stefano Covino at Brera Astronomical Observatory S. Covino (INAF/OAB) on behalf of the REM team: We observed the field of the GRB141221A (Sonbas et al., GCN 17206) simultaneously in the optical and near infrared with the 60-cm robotic telescope REM at La Silla Observatory (Chile). The observations started about 1 min after the GRB, when the field was at an airmass of about 2.5 and continued for about one hour till the local twilight. A bright source at a position consistent with the UVOT candidate afterglow is detected in all filter (grizJHK). At about 1.5 min after the GRB the afterglow was H~13.1 and faded down to H~15.8 more than 30 min later, with a decay index alpha~0.8.
GCN 17209 table
GRB_name GRB141221A
GCN_number 17209
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 17209 SUBJECT: GRB 141221A: LCOGT-McDonald optical afterglow observations DATE: 14/12/21 15:07:45 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy C. Guidorzi, S. Dichiara (U. Ferrara), D. Kopac, A. Gomboc (U. Ljubljana) on behalf of a larger collaboration report: The 1-m LCOGT McDonald telescope began observing Swift GRB 141221A (Sonbas et al. GCN 17206) on Dec 21 at 10:26:35 UT, corresponding to 2.3 hours after the burst trigger, with SDSS r' and i' filters. We detect the optical afterglow (Sonbas et al. GCN 17206; Covino GCN 17208) with i'=20.1 +- 0.3 mag at a mid time of 2.61 hours post burst (total exposure of 600 s).
GCN 17210 table
GRB_name GRB141221A
GCN_number 17210
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 17210 SUBJECT: GRB 141221A: Skynet PROMPT-CTIO observations of the optical afterglow DATE: 14/12/21 15:16:10 GMT FROM: Adam S. Trotter at UNC-Chapel Hill/PROMPT/Skynet A. Trotter, J. Haislip, D. Reichart, A. Aji, R. Beauchemin, T. Berger, A. Dow, A. Foster, N. Frank, M. Hinckle, K. Ivarsen, A. LaCluyze, M. Maples, J. Moore, M. Nysewander, C. Salemi, L. Zbinden, and J. A. Crain report: Skynet observed the Swift BAT/XRT localization of GRB 141221A (Sonbas et al., GCN 17206, Swift trigger=622006) with two 14" telescopes of the PROMPT array at Cerro Tololo, Chile. Starting at 2014-12-21 08:07:56 UT and continuing until 08:35 UT (t=45s-28m post-trigger), Skynet took a total of 44 exposures ranging from 5s to 160s in the V and I bands. We clearly detect the optical afterglow (Covino, GCN 17208, Guidorzi et al., GCN 17209) with a rising light curve prior to t=2min, where it peaks at I=14.8. A preliminary light curve is at: http://www.skynet.unc.edu/grb/grb141221a.png Magnitudes are in the Vega System, calibrated to 3 APASS stars in the field. Magnitudes have not been corrected for line-of-sight Milky Way dust extinction, with expected E(B-V)=0.024 (Schlafly & Finkbeiner 2011). Skynet observations will continue.
GCN 17211 table
GRB_name GRB141221A
GCN_number 17211
Detection_method Swift-XRT Det
ra 198.2869°
decl 8.2051°
Circular_text TITLE: GCN CIRCULAR NUMBER: 17211 SUBJECT: GRB 141221A: Enhanced Swift-XRT position DATE: 14/12/21 17:56:05 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 4183 s of XRT Photon Counting mode data and 6 UVOT images for GRB 141221A, 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 = 198.28686, +8.20510 which is equivalent to: RA (J2000): 13h 13m 8.85s Dec (J2000): +08d 12' 18.4" with an uncertainty of 1.6 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 17212 table
GRB_name GRB141221A
GCN_number 17212
Detection_method GROND
ra 198.2867°
decl 8.2052°
Circular_text TITLE: GCN CIRCULAR NUMBER: 17212 SUBJECT: GRB141221A: GROND Afterglow Detection DATE: 14/12/21 19:03:57 GMT FROM: Philip Wiseman at MPE/Swift GRB 141221A: GROND Detection of the Optical/NIR Afterglow T. Schweyer, P. Wiseman, P. Schady and J. Greiner (all MPE Garching), report on behalf of the GROND team: We observed the field of GRB 141221A (Swift trigger 622006; Sonbas et al., GCN #17206) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile). Observations started at 08:09:33 UT on 21/12/2014, 142 seconds after the GRB trigger, and continued in all bands for ~18 minutes of exposures until the beginning of twilight, and in NIR for another 4 minute exposure. They were performed at an average seeing of 1.7" and at an average airmass of 2.1. We find a single point source, consistent with the enhanced SWIFT-XRT position of Beardmore et al. (GCN #17211) and that reported by e.g. Covino (GCN 17208), Trotter et al. (GCN #17210), at: RA (J2000) = 13h 13m 08.80s DEC (J2000) = +08d 12' 18.9" with an uncertainty of 0.2" in both co-ordinates. There were problems with telescope pointing throughout the observations, Based on our first short exposures in grizJHK, we estimate preliminary magnitudes (all in AB system) of g' = 17.1 +/- 0.1 mag, r' = 16.6 +/- 0.1 mag, i' = 16.4 +/- 0.1 mag, z' = 16.1 +/- 0.1 mag, J = 15.7 +/- 0.1 mag, H = 15.4 +/- 0.1 mag, and K = 15.3 +/- 0.1 mag. The best-fit SED has a spectral index beta = 1.0 +/- 0.1. Given magnitudes are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.024 mag in the direction of the burst (Schlegel et al. 1998).
GCN 17213 table
GRB_name GRB141221A
GCN_number 17213
Detection_method Swift-BAT Det
ra 198.2830°
decl 8.1970°
Circular_text TITLE: GCN CIRCULAR NUMBER: 17213 SUBJECT: GRB 141221A: Swift-BAT refined analysis DATE: 14/12/21 19:28:45 GMT FROM: Scott Barthelmy at NASA/GSFC T. N. Ukwatta (LANL), 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 (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), E. Sonbas (NASA/GSFC/Adiyaman Univ.), M. Stamatikos (OSU), J. Tueller (GSFC) (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 141221A (trigger #622006) (Sonbas, et al., GCN Circ. 17206). The BAT ground-calculated position is RA, Dec = 198.283, 8.197 deg, which is RA(J2000) = 13h 13m 07.9s Dec(J2000) = +08d 11' 49.8" with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 78%. The mask-weighted light curve shows some low-level precursor emission starting at ~T-23 sec with the first peak starting at ~T-3 sec, peaking at ~T+1 sec, and the second peak peaking at ~T+14 sec, and ending at T+35 sec. T90 (15-350 keV) is 36.9 +- 4.0 sec (estimated error including systematics). The time-averaged spectrum from T-24.11 to T+20.33 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.74 +- 0.08. The fluence in the 15-150 keV band is 2.1 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-0.10 sec in the 15-150 keV band is 3.1 +- 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/622006/BA/
GCN 17214 table
GRB_name GRB141221A
GCN_number 17214
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 17214 SUBJECT: GRB 141221A: Swift-XRT refined Analysis DATE: 14/12/21 20:21:04 GMT FROM: Phil Evans at U of Leicester A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), 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 E. Sonbas report on behalf of the Swift-XRT team: We have analysed 8.9 ks of XRT data for GRB 141221A (Sonbas et al. GCN Circ. 17206), from 64 s to 34.9 ks after the BAT trigger. The data comprise 48 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 Beardmore et al. (GCN Circ. 17211). The late-time light curve (from T0+3.9 ks) can be modelled with a power-law decay with a decay index of alpha=1.26 (+0.17, -0.16). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.26 (+0.21, -0.20). The best-fitting absorption column is 3.1 (+0.8, -0.7) x 10^21 cm^-2, in excess of the Galactic value of 2.3 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 3.3 x 10^-11 (5.6 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3.1 (+0.8, -0.7) x 10^21 cm^-2 Galactic foreground: 2.3 x 10^20 cm^-2 Excess significance: 6.7 sigma Photon index: 2.26 (+0.21, -0.20) If the light curve continues to decay with a power-law decay index of 1.26, the count rate at T+24 hours will be 3.5 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x 10^-13 (2.0 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/00622006. This circular is an official product of the Swift-XRT team.
GCN 17216 table
GRB_name GRB141221A
GCN_number 17216
Detection_method Fermi GBM Det
t_trigger 8:07:11.220 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 17216 SUBJECT: GRB 141221A: Fermi GBM observation DATE: 14/12/22 08:29:06 GMT FROM: Hoi-Fung Yu at MPE H.-F. Yu (MPE) reports on behalf of the Fermi GBM Team: "At 08:07:11.22 UT on 21 Dec 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 141221A (trigger 440842034 / 141221338), which was also detected by Swift (Sonbas et al. 2014, GCN 17206). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is about 76 degrees. The GBM light curve consists of two pulses with a duration (T90) of about 23.8 s (50-300 keV). The time-averaged spectrum from T0-1.024 s to T0+17.408 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.07 +/- 0.13 and the cutoff energy, parameterized as Epeak, is 152.4 +/- 28.5 keV. The event fluence (8-1000 keV) in this time interval is (3.4 +/- 0.4)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0-0.192 s in the 8-1000 keV band is 5.4 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN 17219 table
GRB_name GRB141221A
GCN_number 17219
Detection_method Swift-UVOT Det
ra 198.2867°
decl 8.2052°
Circular_text TITLE: GCN CIRCULAR NUMBER: 17219 SUBJECT: GRB 141221A: Swift/UVOT Detection DATE: 14/12/22 17:26:04 GMT FROM: Frank Marshall at GSFC F. E. Marshall (NASA/GSFC) and E. Sonbas (NASA/GSFC/Adiyaman Univ.) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 141221A 84 s after the BAT trigger (Sonbas et al., GCN Circ. 17206). A source consistent with the enhanced XRT position (Beardmore et al. GCN Circ. 17211) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 13:13:08.81 = 198.28672 (deg.) Dec (J2000) = +08:12:18.8 = 8.20522 (deg.) with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence). Preliminary detections 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 84 234 147 17.33 0.04 v 626 646 19 17.43 0.26 b 552 571 20 17.92 0.21 u 296 546 246 17.62 0.07 w1 4061 4261 197 >20.0 m2 3856 10742 414 >20.9 w2 6231 6399 165 >20.5 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).
GCN 17221 table
GRB_name GRB141221A
GCN_number 17221
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 17221 SUBJECT: GRB 141221A: Continued Skynet PROMPT-CTIO observations DATE: 14/12/22 20:18:17 GMT FROM: Adam S. Trotter at UNC-Chapel Hill/PROMPT/Skynet A. Trotter, J. Haislip, D. Reichart, A. Aji, R. Beauchemin, T. Berger, A. Dow, A. Foster, N. Frank, M. Hinckle, K. Ivarsen, A. LaCluyze, M. Maples, J. Moore, M. Nysewander, C. Salemi, L. Zbinden, and J. A. Crain report: Skynet continued to observe the Swift UVOT localization of GRB 141221A (Sonbas et al., GCN 17206, Swift trigger=622006) with two 16" telescopes of the PROMPT array at Cerro Tololo, Chile. Starting at 2014-12-22 07:08 UT and continuing until 08:34 UT (t=23.0h-24.5h post-trigger), Skynet took a total of 64 exposures of 160s each in the V and I bands. We stacked subsets of these images to maximize the signal-to-noise ratio. We no longer detect the optical afterglow that we described in Trotter et al. (GCN 17210). Our limiting magnitudes are: ================================== tmid expos fil limit ================================== 23.8h 32x160s V >21.2 23.8h 31x160s I >20.7 A preliminary light curve is at: http://www.skynet.unc.edu/grb/grb141221a_2.png Magnitudes are in the Vega System, calibrated to 3 APASS stars in the field. Magnitudes have not been corrected for line-of-sight Milky Way dust extinction, with expected E(B-V)=0.024 (Schlafly & Finkbeiner 2011). No further Skynet observations are scheduled.
GCN 17222 table
GRB_name GRB141221A
GCN_number 17222
Detection_method MITSuME
Circular_text TITLE: GCN CIRCULAR NUMBER: 17222 SUBJECT: GRB 141221A: MITSuME Akeno upper limits DATE: 14/12/23 11:00:16 GMT FROM: Taketoshi Yoshii at Tokyo Tech Y. Ono, T. Yoshii, Y. Saito, Y. Tachibana, H. Ohuchi, Y. Yano, S. Kurita, T. Fujiwara, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 141221A (E .Sonbas et al., GCN Circular #17206) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The observation started on 2014-12-21 17:20:13 UT (~9.1 h after the burst). We did not find any new point source within the refined XRT error circle (A.P. Beardmore., GCN Circular #17211) in all the three bands. The measured magnitudes are listed below. T0+[sec] MID-UT T-EXP[sec] g' Rc Ic ----------------------------------------------------------------------------- 33183 18:51:55 9600 >21.3 >20.8 >20.2 ----------------------------------------------------------------------------- T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used GSC2.3 catalog for flux calibration.
GCN 17227 table
GRB_name GRB141221A
GCN_number 17227
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 17227 SUBJECT: GRB 141221A: TAROT La Silla observatory optical observations DATE: 14/12/24 14:38:04 GMT FROM: Alain Klotz at IRAP-CNRS-OMP Klotz A., Turpin D. (IRAP-CNRS-OMP), Boer M., Gendre B., Siellez K., Dereli H., Bardho O. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report: We imaged the field of GRB 141221A detected by SWIFT (trigger 622006) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 31.2s after the GRB trigger (14.2s after the notice). The elevation of the field increased from 23 degrees above horizon and weather conditions were good but the dawn interrupted the observations after 41 minutes. The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect the optical counterpart between 31s and 68s at a limiting magnitude Rlim = 16.6. Then the end of the trail shows a sudden appearance of the optical counterpart (cf. Sonbas et al. GCNC 17206). Measures are: start end magnitude (sec) (sec) 31.2 68.5 Rlim = 16.6 68.5 74.5 R = 16.0 +/- 0.2 74.5 80.5 R = 15.7 +/- 0.2 80.5 86.5 R = 15.5 +/- 0.2 86.5 92.5 R = 15.6 +/- 0.3 Next images (in tracking mode) show the optical transcient: start end magnitude (sec) (sec) R +/- 104.6 134.6 15.47 0.03 145.1 175.1 15.36 0.03 185.7 215.7 15.40 0.03 226.0 256.0 15.42 0.03 266.3 296.3 15.39 0.03 306.7 396.7 15.60 0.09 401.3 491.3 16.17 0.02 715.6 805.6 16.63 0.02 816.2 906.2 16.68 0.08 1029.4 1119.4 16.95 0.08 1130 1525 17.22 0.08 1536 2486 17.82 0.08 The early afterglow observed by TAROT is compatible with that observed by PROMPT (Trotter et al. GCNC 17210 and GCNC 17221). Magnitudes were estimated with the nearby star NOMAD-1 0982-0272573 R=12.23 and are not corrected for galactic dust extinction.
GCN 17228 table
GRB_name GRB141221A
GCN_number 17228
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 17228 SUBJECT: GRB 141221A: Keck spectroscopy DATE: 14/12/25 13:26:00 GMT FROM: Daniel Perley at Caltech D. A. Perley, Y. Cao (Caltech), and S. B. Cenko (GSFC) report: We observed the optical afterglow of GRB 141221A (Sonbas et al., GCN 17206) with the DEIMOS spectrograph on the Keck II telescope between 12:48 and 13:10 UT on 2014-12-21. Two 900-second exposures were acquired at high airmass. We detect significant continuum flux across the entire spectral range between 4490-9660 Angstroms. Inspection of the 1D spectrum shows two apparent absorption features at 6854 and 6873 Angstroms which we tentatively associate with the Mg II doublet at z=1.452. Lower-significance probable absorption lines are also seen at the wavelengths of the Fe II 2599, 2585, 2383, 2374, and 2344 lines at similar redshift, lending additional credence to this association. However, due to a failure of the blue arc calibration lamps, we note that our wavelength solution is preliminary and this result should be considered tentative.