GRB170208B

This page lists all entries on GRB170208B in GRBweb

Summary Fermi GBM IPN Swift GCN 20632 GCN 20635 GCN 20636 GCN 20637 GCN 20638 GCN 20640 GCN 20643 GCN 20646 GCN 20647 GCN 20651 GCN 20654 GCN 20655 GCN 20657 GCN 20673 GCN 20674

Summary table
Variable Value Source
GRB_name_Fermi GRB170208940
T0 22:33:28.596 UTC Fermi_GBM
ra 127.1440° Swift
decl -9.0299° Swift
pos_error 2.07e-04° Swift
T90 22.016 s Fermi_GBM
T90_error 1.639 s Fermi_GBM
T90_start 22:33:28.596 UTC Fermi_GBM
fluence 1.03e-05 erg/cm² Fermi_GBM
fluence_error 2.54e-08 erg/cm² Fermi_GBM
T100 137.474 s
GBM_located False
mjd 57792.939914305556 Fermi_GBM
Fermi GBM table
GRB_name_Fermi GRB170208940
trigger_name bn170208940
ra 127.1442°
decl -9.0297°
pos_error 2.92e+00°
datum 2017-02-08
t_trigger 22:33:36.532 UTC
T90 22.016 s
T90_error 1.639 s
T90_start 22:33:28.596 UTC
fluence 1.03e-05 erg/cm²
fluence_error 2.54e-08 erg/cm²
flux_1024 1.21e+01 erg/cm²/s
flux_1024_error 2.75e-01 erg/cm²/s
flux_1024_time 2.56e+00 erg/cm²/s
flux_64 1.47e+01 erg/cm²/s
flux_64_error 1.32e+00 erg/cm²/s
IPN table
GRB_name GRB170208B
ra 127.1542°
decl -9.0333°
pos_error 5.00e-02°
Swift table
GRB_name GRB170208B
t_trigger 22:33:38 UTC
ra 127.1440°
decl -9.0299°
pos_error 2.07e-04°
T90 128.07 s
fluence 6.10e-06 erg/cm²
GCN 20632 table
GRB_name GRB170208B
GCN_number 20632
Detection_method Swift Det
t_trigger 22:33:38 UTC
ra 127.1550°
decl -9.0270°
Circular_text TITLE: GCN CIRCULAR NUMBER: 20632 SUBJECT: GRB 170208B: Swift detection of a burst DATE: 17/02/08 22:50:18 GMT FROM: Scott Barthelmy at NASA/GSFC M. H. Siegel (PSU), S. D. Barthelmy (GSFC), A. Cholden-Brown (PSU), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 22:33:38 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 170208B (trigger=737463). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 127.155, -9.027 which is RA(J2000) = 08h 28m 37s Dec(J2000) = -09d 01' 35" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several overlapping peaks with a total duration of about 40 sec. The peak count rate was ~14,500 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 22:34:40.6 UT, 61.8 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 127.14389, -9.02979 which is equivalent to: RA(J2000) = 08h 28m 34.53s Dec(J2000) = -09d 01' 47.2" with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 40 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 (5.32 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 2.9 (+2.27/-2.01) x 10^21 cm^-2 (90% confidence). The initial flux in the 2.5 s image was 7.16e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 250 seconds with the U filter starting 126 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 19.2 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 18.0 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.05. Burst Advocate for this burst is M. H. Siegel (siegel AT swift.psu.edu). 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 20635 table
GRB_name GRB170208B
GCN_number 20635
Detection_method Swift-XRT Det
ra 127.1439°
decl -9.0300°
Circular_text TITLE: GCN CIRCULAR NUMBER: 20635 SUBJECT: GRB 170208B: Enhanced Swift-XRT position DATE: 17/02/09 02:43:34 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 1870 s of XRT Photon Counting mode data and 2 UVOT images for GRB 170208B, 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 = 127.14385, -9.03002 which is equivalent to: RA (J2000): 08h 28m 34.52s Dec (J2000): -09d 01' 48.1" with an uncertainty of 2.2 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 20636 table
GRB_name GRB170208B
GCN_number 20636
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 20636 SUBJECT: GRB 170208B: Etelman observatory optical observations DATE: 17/02/09 05:22:46 GMT FROM: Bruce Gendre at ASDC B. Gendre (UVI), N. Orange (OrangeWave Innovative Science, LLC), D. Morris (UVI), A. Cucchiara (UVI), D. Drost (UVI), T. Giblin (USAF Academy), J. Hakkila (College of Charleston), A. Klotz (IRAP), J. Neff (NSF), D. Smith (UVI), J. Staff (UVI), P. Thierry (Auragne Observatory), R. Watlington (UVI), and L. Wentlent (UVI) report: We observed the field of GRB 170208B (Siegel et al., GCN 20632) with the 0.5m Virgin Island Robotic Telescope (VIRT) on February the 9th, starting at 3:10 UT (4.7 hours after the trigger). We performed a series of exposures in the clear filter. The weather conditions were good during the first hour of observation. We co-added the exposures taken between 3h10UT and 4h17UT. At the position of the X-ray afterglow reported by Goad et al. (GCN 20635), we do not detect any optical emission, with an upper limit of R ~ 19 (estimated from nearby USNO-B1 stars). Magnitudes have not been corrected for Galactic extinction. The VIRT is still in its commissioning phase. This message can be cited.
GCN 20637 table
GRB_name GRB170208B
GCN_number 20637
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 20637 SUBJECT: GRB 170208B: Swift-XRT refined Analysis DATE: 17/02/09 09:00:40 GMT FROM: Phil Evans at U of Leicester J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), B. Mingo (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), D.N. Burrows (PSU) and M.H. Siegel report on behalf of the Swift-XRT team: We have analysed 6.4 ks of XRT data for GRB 170208B (Siegel et al. GCN Circ. 20632), from 50 s to 24.0 ks after the BAT trigger. The data comprise 260 s in Windowed Timing (WT) mode (the first 9 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 Goad et al. (GCN Circ. 20635). The late-time light curve (from T0+5.4 ks) can be modelled with a power-law decay with a decay index of alpha=0.81 (+0.19, -0.20). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.46 (+/-0.05). The best-fitting absorption column is 4.34 (+/-0.21) x 10^21 cm^-2, in excess of the Galactic value of 5.3 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.07 (+0.15, -0.14) and a best-fitting absorption column of 3.7 (+0.7, -0.6) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (5.9 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3.7 (+0.7, -0.6) x 10^21 cm^-2 Galactic foreground: 5.3 x 10^20 cm^-2 Excess significance: 8.5 sigma Photon index: 2.07 (+0.15, -0.14) If the light curve continues to decay with a power-law decay index of 0.81, the count rate at T+24 hours will be 0.020 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.6 x 10^-13 (1.2 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00737463. This circular is an official product of the Swift-XRT team.
GCN 20638 table
GRB_name GRB170208B
GCN_number 20638
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 20638 SUBJECT: GRB 170208B: NOT upper limits DATE: 17/02/09 11:33:49 GMT FROM: Kasper Elm Heintz at Univ. of Iceland and DARK/NBI K. E. Heintz (Univ. Iceland and DARK/NBI), D. Malesani (DARK/NBI and DTU Space), N. R. Tanvir (Univ. Leicester), A. de Ugarte Postigo (IAA-CSIC and DARK/NBI), A. J. Korn (Uppsala Univ.) and I. R. Losada (NOT, NORDITA, and Stockholm Univ.) report on behalf of a larger collaboration: We observed the field of GRB 170208B (Siegel et al., GCN 20632) using the ALFOSC instrument equipped at the 2.56-m Nordic Optical Telescope (NOT). Observations started at 23:24:13.1 UT on 2017-02-08 (i.e., 50.5 min after the trigger). We obtained SDSS r- and z-band images with 3x300 s and 4x200 s exposures, respectively. The weather conditions were good with a measured seeing of 1.6 and 1.3 arcsec in the r- and z-band, respectively. In the stacked r- and z-bands no optical afterglow of the burst is detected within the XRT error circle (Goad et al., 20635) at limiting magnitudes of m(r) < 22.5 and m(z) < 22.2 (all AB) mag, calibrated with nearby stars from the Pan-STARRS survey.
GCN 20640 table
GRB_name GRB170208B
GCN_number 20640
Detection_method Optical
ra 127.1440°
decl -9.0273°
Circular_text TITLE: GCN CIRCULAR NUMBER: 20640 SUBJECT: GRB 170208B: GROND observations DATE: 17/02/09 14:08:32 GMT FROM: Thomas Kruehler at MPE Garching T. Kruehler (MPE Garching) reports: I observed the field of GRB 170208B (Swift trigger 737463; Siegel et al. GCN 20632) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at the ESO La Silla Observatory (Chile). Observations started at 01:22 UT on 2017-02-09, 2.8 hr after the GRB trigger and reveal a faint optical source centered at: RA (J2000): 08:28:34.55 Dec (J2000): -09:01:38.1 which is 2.0" away from the center of the XRT error circle (Goad et al. GCN 20635, current 90% error radius of 1.6"). Based on combined images with 66 min of total exposures in g'r'i'z' and 60.0 min in JHK at a mid-time of 02:39 UT on 2017-02-09, this source has the following preliminary magnitudes and upper limits (all in the AB system): g' = 24.5 +- 0.4 mag r' = 24.4 +- 0.3 mag i' = 23.4 +- 0.2 mag z' = 23.1 +- 0.2 mag J > 21.3 mag H > 21.0 mag K > 19.0 mag Given magnitudes are calibrated against Pan-STARRS and 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.042 mag in the direction of the burst (Schlafly & Finkbeiner 2011). This source is marginally detected already in the archival Pan-STARRS imaging of the field, so it is not the GRB 170208B afterglow. It is, however, a possible host galaxy candidate (the chance coincidence probability of finding a similarly bright object at 2" from the XRT position is around 6%). I acknowledge excellent help in obtaining these data from the supporting astronomers on La Silla, Sam Kim and Simon Steinmassl.
GCN 20643 table
GRB_name GRB170208B
GCN_number 20643
Detection_method Konus-Wind Det
t_trigger 22:33:42.750 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 20643 SUBJECT: Konus-Wind observation of GRB 170208B DATE: 17/02/09 14:39:18 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, P. Oleynik, M. Ulanov, A. Tsvetkova, A. Lysenko, A.Kozlova, and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 170208B (Swift-BAT detection: Siegel et al., GCN Circ. 20632) triggered Konus-Wind at T0=81222.750 s UT (22:33:42.750). The burst light curve shows a single emission episode started at ~T0-5 s with a total duration of ~11 s. The emission is seen up to ~1 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB170208_T81222/ As observed by Konus-Wind, the burst had a fluence of 8.17(-0.44,+0.46)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0+1.072 s, of 2.55(-0.82,+0.82)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 1 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.78(-0.23,+0.25) and Ep = 105(-7,+8) keV (chi2 = 40/51 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -3.0 (chi2 = 39/50 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN 20646 table
GRB_name GRB170208B
GCN_number 20646
Detection_method Fermi GBM Det
t_trigger 22:33:36.530 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 20646 SUBJECT: GRB 170208B: Fermi GBM Detection DATE: 17/02/09 15:19:35 GMT FROM: Oliver J Roberts at USRA/NASA O.J. Roberts (USRA/NASA) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 22:33:36.53 UT on the 8th of February 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 170208B (trigger 508286021 / 170208940), which was also detected by Konus-Wind (Svinkin et al. 2017, GCN 20643) and Swift (Siegel et al. 2017, GCN 20632). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time using the Swift-XRT position is 54 degrees. The GBM light curve consists of a long GRB with overlapping episodes of bright emission over a duration (T90) of about 22 s (50-300 keV). The time-averaged spectrum from T0-8.0 s to T0+14.0 s is adequately fit by a Band function with Epeak = 104.1 +/- 5.5 keV, alpha = -0.83 +/- 0.05, and beta = -2.33 +/- 0.09 The event fluence (10-1000 keV) in this time interval is (1.13 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0-7.9 s in the 10-1000 keV band is 12.1 +/- 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 20647 table
GRB_name GRB170208B
GCN_number 20647
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 20647 SUBJECT: GRB 170208B WHT nIR candidate afterglow DATE: 17/02/09 16:50:56 GMT FROM: Nial Tanvir at U.Leicester K. Wiersema, N. R. Tanvir (U. Leicester), A. J. Levan (U. Warwick), R. Karjalainen, F. Riddick (ING) report on behalf of a larger collaboration: We observed the field of Swift GRB 170208B (Siegel et al. GCN 20632) with the 4.2m William Herschel Telescope on La Palma. Images were obtained in the Y,J,H,K filters with LIRIS. In the K-band exposure, for which the mid-time was 2.54 hr post-burst, we find a source with magnitude K(AB)=21.1+/-0.1 within the revised X-ray error circle (Goad et al. GCN 20635). The source is absent (or very marginally present) in the other infrared filters, which were observed somewhat earlier, to AB mag limits of about 22.5 in each band. The position of this source is: RA(2000)=08:28:34.55 dec(2000)=-9:01:47.8 This is about 1.8 arcsec south of the steady optical source seen by GROND and Pan-STARRS (Kruehler GCN 20640; we note there was a typo in the declination coordinate reported in GCN 20640, Kruehler priv. comm.). We suggest that the K-band source is most likely the afterglow of the GRB, and is not seen in bluer filters due to dust extinction, while the optical source may be the host galaxy.
GCN 20651 table
GRB_name GRB170208B
GCN_number 20651
Detection_method Other
ra 127.1440°
decl -9.0295°
Circular_text TITLE: GCN CIRCULAR NUMBER: 20651 SUBJECT: Correction to GCN 20640: GRB 170208B: GROND observations DATE: 17/02/09 22:12:53 GMT FROM: Thomas Kruehler at MPE Garching T. Kruehler (MPE Garching) reports: The declination of the source mentioned in my original GCN 20640 contained an error. The correct position is: RA (J2000): 08:28:34.55 Dec (J2000): -09:01:46.1 I thank N. R. Tanvir for pointing out the error.
GCN 20654 table
GRB_name GRB170208B
GCN_number 20654
Detection_method Swift-BAT Det
ra 127.1450°
decl -9.0270°
Circular_text TITLE: GCN CIRCULAR NUMBER: 20654 SUBJECT: GRB 170208B: Swift-BAT refined analysis DATE: 17/02/09 22:55:28 GMT FROM: Amy Lien at GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), N. Gehrels (GSFC), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU), M. H. Siegel (PSU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-240 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170208B (trigger #737463) (Siegel et al., GCN Circ. 20632). The BAT ground-calculated position is RA, Dec = 127.145, -9.027 deg which is RA(J2000) = 08h 28m 34.7s Dec(J2000) = -09d 01' 36.1" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a bright pulse structure with several overlapping peaks that starts at ~T-5 s and ends at ~T+15 s, followed by a weaker pulse from ~T+100 s to ~T+160 s. There are also some weak emissions that start at ~T-20 s, prior to the first bright pulse. The short spike with duration of ~ 4 ms seen in 15-25 keV at ~T+191.3 s is due to instrumental noise. T90 (15-350 keV) is 128.07 +- 5.75 sec (estimated error including systematics). The time-averaged spectrum from T-18.20 to T+159.30 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.18 +- 0.21, and Epeak of 97.8 +- 27.4 keV (chi squared 57.4 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 6.1 +- 0.2 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+0.42 sec in the 15-150 keV band is 8.4 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.62 +- 0.05 (chi squared 71.7 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/737463/BA/
GCN 20655 table
GRB_name GRB170208B
GCN_number 20655
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 20655 SUBJECT: GRB 170208B: RATIR Optical and NIR Observations DATE: 17/02/09 23:48:46 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), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report: We observed the field of GRB 170208B (Siegel, et al., GCN 20632) 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 2017/02 9.11 to 2017/02 9.47 UTC (3.98 to 12.65 hours after the BAT trigger), obtaining a total of 6.02 hours exposure in the r and i bands and 2.52 hours exposure in the Z and Y bands. We do not detect either the GROND (Kruehler, et al., GCN 20640) source or the WHT (Wiersema, et al., GCN 20647) source. In comparison with the USNO-B1 and 2MASS catalogs, we obtain the following upper limits (3-sigma): r > 23.56 i > 23.43 Z > 22.64 Y > 22.55 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. The lack of detection of the WHT source is consistent with this source being reddened due to dust or due to a high-z origin if the GROND source is not the GRB host galaxy. The first possibility is also suggested by the significant X-ray column density relative to the Galactic value (Kennea, et al., GCN 20637). We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.
GCN 20657 table
GRB_name GRB170208B
GCN_number 20657
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 20657 SUBJECT: GRB 170208B: Swift/UVOT Upper Limits DATE: 17/02/10 01:47:01 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 170208B 127 s after the BAT trigger (Siegel et al., GCN Circ. 20632). No optical afterglow consistent with the enhanced XRT position (Goad et al. GCN Circ. 20635) or the GROND position (Kruehler et al., GCN Circ. 20640) 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 u_FC 127 377 246 >20.7 v 432 2146 214 >19.6 b 382 2096 233 >20.3 u 127 2211 598 >21.3 w1 482 2195 214 >20.1 m2 457 2171 214 >19.9 w2 408 2122 234 >19.7 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.05 in the direction of the burst (Schlegel et al. 1998).
GCN 20673 table
GRB_name GRB170208B
GCN_number 20673
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 20673 SUBJECT: GRB 170208B: IRSF upper limits DATE: 17/02/14 07:28:56 GMT FROM: Katsuhiro L. Murata at Nagoya U K. L. Murata (Nagoya U), L. Townsend (UCT), I. Monageng (SAAO), Y. Moritani (Kavli IPMU), M. Jian (U of Tokyo), S. Chimasu (Tokai U), A. Kawachi (Tokai U), A. Okazaki (Hokkai-Gakuen U) and T. Nagayama (Kagoshima U) We observed the field of GRB 170208B (Siegel et al., GCN Circular #20632) with the near-infrared (J, H, Ks) simultaneous imaging camera SIRIUS attached to 1.4 m telescope IRSF (InfraRed Survey Facility) in Sutherland observatory, South Africa. The observations started on 2017-02-08 22:49:41 UT (~ 15 min. after the burst). We could not detect the afterglow within the enhanced XRT error circle (Goad et al., GCN Circular #20635) in the three bands. We have obtained the following preliminary upper limits (Vega magnitude system): J > 16.83 H > 16.31 Ks > 16.30 Given magnitudes were calibrated against 2MASS point sources in this field. The upper limits were determined as the magnitudes of the faintest star within 1 arcmin from the enhanced XRT position. This observation was carried out by IRSF and OISTER collaboration.
GCN 20674 table
GRB_name GRB170208B
GCN_number 20674
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 20674 SUBJECT: GRB 170208B: SMARTS optical/IR observations DATE: 17/02/14 19:48:17 GMT FROM: Bethany Cobb at GWU B. E. Cobb (GWU) reports: Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained optical/IR imaging of the error region of GRB 170208B (GCN 20632, Siegel et al.) with a mid-exposure time of about 5.1 hours post-burst (2017-02-09 03:38 UT). Total summed exposure times amounted to 36 minutes in I and 30 minutes in J. No source is detected at the position of the X-ray afterglow (GCN 20635, Goad et al.) to approximate limiting magnitudes of I > 20.9 and J > 19.4. Magnitudes are calibrated using Landolt standard stars in I and 2MASS stars in J.