GRB151027A

This page lists all entries on GRB151027A in GRBweb

Summary Fermi GBM IPN Swift GCN 18478 GCN 18479 GCN 18480 GCN 18481 GCN 18482 GCN 18483 GCN 18485 GCN 18487 GCN 18490 GCN 18491 GCN 18492 GCN 18493 GCN 18495 GCN 18496 GCN 18502 GCN 18503 GCN 18508 GCN 18510 GCN 18513 GCN 18515 GCN 18516 GCN 18518 GCN 18519 GCN 18521 GCN 18525 GCN 18533 GCN 18537 GCN 18539 GCN 18552 GCN 18555 GCN 18558 GCN 18559 GCN 18567 GCN 18575 GCN 18608 GCN 18609 GCN 18616 GCN 18620 GCN 18635

Summary table
Variable Value Source
GRB_name_Fermi GRB151027166
T0 3:58:24 UTC GCN_circulars,Swift Det
ra 272.4869° Swift
decl 61.3533° Swift
pos_error 1.81e-04° Swift
T90 123.394 s Fermi_GBM
T90_error 1.145 s Fermi_GBM
T90_start 3:58:24.289 UTC Fermi_GBM
fluence 1.41e-05 erg/cm² Fermi_GBM
fluence_error 6.10e-08 erg/cm² Fermi_GBM
redshift 0.8100 GCN_circulars,Swift-XRT Other
T100 129.69 s
GBM_located False
mjd 57322.165555555555 GCN_circulars,Swift Det
Fermi GBM table
GRB_name_Fermi GRB151027166
trigger_name bn151027166
ra 272.4871°
decl 61.3533°
pos_error 2.60e+00°
datum 2015-10-27
t_trigger 3:58:24.033 UTC
T90 123.394 s
T90_error 1.145 s
T90_start 3:58:24.289 UTC
fluence 1.41e-05 erg/cm²
fluence_error 6.10e-08 erg/cm²
flux_1024 1.14e+01 erg/cm²/s
flux_1024_error 3.43e-01 erg/cm²/s
flux_1024_time 3.84e-01 erg/cm²/s
flux_64 1.31e+01 erg/cm²/s
flux_64_error 1.37e+00 erg/cm²/s
IPN table
GRB_name GRB151027A
ra 272.4917°
decl 61.3833°
pos_error 5.00e-02°
redshift 0.8100
Swift table
GRB_name GRB151027A
t_trigger 3:58:24 UTC
ra 272.4869°
decl 61.3533°
pos_error 1.81e-04°
T90 129.69 s
fluence 7.80e-06 erg/cm²
redshift 0.3800
GCN 18478 table
GRB_name GRB151027A
GCN_number 18478
Detection_method Swift Det
t_trigger 3:58:24 UTC
ra 272.4910°
decl 61.3810°
Circular_text TITLE: GCN CIRCULAR NUMBER: 18478 SUBJECT: GRB 151027A: Swift detection of a burst with a bright optical afterglow DATE: 15/10/27 04:16:31 GMT FROM: David Palmer at LANL A. Maselli (INAF-IASFPA), A. D'Ai (INAF-IASFPA), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC) and T. N. Ukwatta (LANL) report on behalf of the Swift Team: At 03:58:24 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 151027A (trigger=661775). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 272.491, +61.381 which is RA(J2000) = 18h 09m 58s Dec(J2000) = +61d 22' 51" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex peaked structure lasting at least 150 seconds. The peak count rate was ~6000 counts/sec (15-350 keV), at ~110 sec after the trigger. The XRT began observing the field at 03:59:51.1 UT, 87.0 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 272.4886, 61.3515 which is equivalent to: RA(J2000) = +18h 09m 57.26s Dec(J2000) = +61d 21' 05.4" with an uncertainty of 4.8 arcseconds (radius, 90% containment). This location is 106 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. UVOT took a finding chart exposure of 150 seconds with the White filter starting 95 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 18:09:56.68 = 272.48615 DEC(J2000) = +61:21:13.4 = 61.35373 with a 90%-confidence error radius of about 0.61 arc sec. This position is 9.06 arc sec. from the center of the XRT error circle. The estimated magnitude is 14.46 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.05. Burst Advocate for this burst is A. Maselli (maselli AT ifc.inaf.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 18479 table
GRB_name GRB151027A
GCN_number 18479
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18479 SUBJECT: GRB 151027A: KAIT optical afterglow confirmation DATE: 15/10/27 04:22:02 GMT FROM: Weikang Zheng at UC Berkeley WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to Swift GRB 151027A (Maselli et al., GCN 18478) immediately after receiving the trigger. Observations were performed with an automatic sequence in the clear (roughly R), V, and I filters, and the exposure time was 20 s per image. Inside the XRT error circle we detected an un-cataloged varying source with coordinates of : RA = 18:09:56.70 (J2000) DEC= +61:21:13.01 (J2000) The object location is consistent with the position reported from UVOT (Maselli et al., GCN 18478). The object has clear band mag of ~13.0 at the moment. Follow-up observations are encouraged.
GCN 18480 table
GRB_name GRB151027A
GCN_number 18480
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18480 SUBJECT: GRB 151027A : ISON-NM early optical detection DATE: 15/10/27 05:47:05 GMT FROM: Alexei Pozanenko at IKI, Moscow L. Elenin (KIAM), E. Mazaeva (IKI), A. Volnova (IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of the Swift GRB 151027A (Maselli et al., GCN 18478) with 0.4-m telescope of ISON-NM observatory in robotic mode starting on Oct., 27 (UT) 03:59:43 i.e. 79 seconds after burst trigger. We obtained 50 unfiltered images of 30 s exposure. We clearly detect the optical counterpart of GRB 151027A (Maselli et al., GCN 18478; Zheng and Filippenko, GCN 18479) in coordinates (J2000) 18 09 56.69 +61 21 13.2. In the first image we estimated brightness of the optical counterpart as ~14m.
GCN 18481 table
GRB_name GRB151027A
GCN_number 18481
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 18481 SUBJECT: GRB 151027A: P60 afterglow confirmation and rebrightening DATE: 15/10/27 05:57:03 GMT FROM: Daniel Perley at Caltech D. A. Perley (DARK/NBI) and S. B. Cenko (NASA/GSFC) report: The Palomar 60-inch robotic telescope responded automatically to the alert for GRB 151027A (Maselli et al., GCN151027A) and began a sequence of i, r, and z-band imaging at 04:00:49 UT, 145 seconds after the BAT trigger. We identify a very bright afterglow consistent with the UVOT and KAIT (Zheng et al., GCN18479) positions in all filters. The preliminary afterglow light curve shows a slow rise to a peak at about ~5 minutes after the GRB trigger, then slowly fades by about 1 magnitude between then and approximately 30 minutes after the trigger. Over the next 20 minutes it then rapidly rebrightens by about 0.7 magnitude. Little or no fading is seen after that point (through to at least 90 minutes after the trigger.) Continued monitoring is encouraged, and should remain possible even from small telescopes for quite some time. High-resolution spectroscopy is also strongly encouraged.
GCN 18482 table
GRB_name GRB151027A
GCN_number 18482
Detection_method Swift-XRT Det
ra 272.4869°
decl 61.3534°
Circular_text TITLE: GCN CIRCULAR NUMBER: 18482 SUBJECT: GRB 151027A: Enhanced Swift-XRT position DATE: 15/10/27 09:37:18 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 1445 s of XRT Photon Counting mode data and 3 UVOT images for GRB 151027A, 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 = 272.48695, +61.35344 which is equivalent to: RA (J2000): 18h 09m 56.87s Dec (J2000): +61d 21' 12.4" 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 18483 table
GRB_name GRB151027A
GCN_number 18483
Detection_method Swift-XRT Other
redshift 0.3800
Circular_text TITLE: GCN CIRCULAR NUMBER: 18483 SUBJECT: Tentative redshift for GRB 151027A from Swift-XRT data DATE: 15/10/27 10:03:40 GMT FROM: Sergio Campana at INAF-OAB S. Campana (INAF-OAB) report on behalf of the Swift Team: Swift BAT triggered on the early activity of GRB 151027A (Maselli et al. 2015, GCN 18478). Swift XRT started observing 87 s after the trigger observing the main event. By using the Swift/XRT spectrum repository at http://www.swift.ac.uk/xrt_spectra/ (see Evans et al. 2009, MNRAS, 397, 1177) we selected a time interval with an almost constant hardness ratio, starting at 150 s after the burst onset and lasting 281 s. We then fit the Window Timing (WT) spectrum with XSPEC using the model tbabs*ztbabs*pow. We assume a Galactic column density of 3.75x10^20 cm^-2 (Willingale et al. 2013, MNRAS, 431, 394) and we allow for a 30% uncertainty in the fit. We fit the spectrum using C-statistics (C-stat=593.74 with 637 d.o.f.). In the intrinsic column density vs. redshift plane there is just one deep minimum hinting for a redshift z=0.38+/-0.17 (90% confidence level) and an intrinsic column density N_H(z)=(3.6+/-0.7)x10^21 cm^-2. The X-ray spectrum is soft with Gamma=2.6, (assuming a cut-off power law spectrum the allowed redshift range expands to 0.27-1.38). The contour plot is available at http://www.brera.inaf.it/utenti/campana/151027.gif
GCN 18485 table
GRB_name GRB151027A
GCN_number 18485
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18485 SUBJECT: GRB 151027A: Weihai optical observations DATE: 15/10/27 12:17:48 GMT FROM: Dong Xu at NAOC/CAS D. Xu (NAOC/CAS), C.-M. Zhang, C. Cao, S.-M. Hu (SDU) report: We observed the field of GRB 151027A (Maselli et al., GCN 18478) using the 1m telescope located at Weihai, Shandong, China. Observations started at 09:44 UT on 2015-07-27, i.e., 5.77 hr after the burst. We obtained 5x300s R-band and 5x150s I-band frames. The afterglow (e.g., Maselli et al., GCN 18478; Zheng & Filippenko, GCN 18479; Elenin et al., GCN 18480; Perley & Cenko, GCN 18481) is clearly detected in each image, and it has decayed to m(R) = 16.0 +/- 0.1 mag for the first R-band exposure, calibrated with the nearby USNO B1 stars (with R2 magnitudes).
GCN 18487 table
GRB_name GRB151027A
GCN_number 18487
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18487 SUBJECT: GRB 151027A: Keck/HIRES redshift DATE: 15/10/27 13:57:31 GMT FROM: Daniel Perley at Caltech D. A. Perley (DARK/NBI), L. Hillenbrand (Caltech), and J. X. Prochaska (UCO/Lick) report: We obtained a 900s spectrum of the optical afterglow of GRB 151027A (Maselli et al., GCN 18478) with Keck/HIRES starting at UT 06:54 on 2015-10-27. In the preliminary reduction, we identify a series of strong absorption lines including the MgII doublet at z=0.81. Associated MgI, FeII, and (likely) FeII* are also present, indicating that this is the redshift of the GRB. Analysis is ongoing.
GCN 18490 table
GRB_name GRB151027A
GCN_number 18490
Detection_method Swift-XRT Other
redshift 0.8100
Circular_text TITLE: GCN CIRCULAR NUMBER: 18490 SUBJECT: GRB 151027A: Swift-XRT refined Analysis DATE: 15/10/27 16:16:03 GMT FROM: Phil Evans at U of Leicester K.L. Page (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'ai (INAF-IASFPA), T.G.R. Roegiers (PSU), L.M. McCauley (PSU), J.A. Kennea (PSU), C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester) and A. Maselli report on behalf of the Swift-XRT team: We have analysed 6.0 ks of XRT data for GRB 151027A (Maselli et al. GCN Circ. 18478), from 80 s to 18.9 ks after the BAT trigger. The data comprise 1.6 ks in Windowed Timing (WT) mode (the first 5 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. 18482). The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=4.1 (+1.1, -1.0). At T+208 s the decay flattens to an alpha of 1.46 (+0.10, -0.14). The light curve breaks again at T+537 s to a decay with alpha=0.04 (+0.06, -0.09), and again at T+2494 s s to alpha=1.11 (+0.15, -0.26), before a final break at T+11.6 ks s after which the decay index is 2.01 (+0.26, -0.25). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.851 (+0.024, -0.023). The best-fitting absorption column is 1.96 (+0.18, -0.17) x 10^21 cm^-2, at a redshift of 0.81, in addition to the Galactic value of 3.8 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.99 (+/-0.08) and a best-fitting absorption column of 3.3 (+/-0.6) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.5 x 10^-11 (4.7 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Galactic foreground: 3.8 x 10^20 cm^-2 Intrinsic column: 3.3 (+/-0.6) x 10^21 cm^-2 at z=0.81 Photon index: 1.99 (+/-0.08) If the light curve continues to decay with a power-law decay index of 2.01, the count rate at T+24 hours will be 0.035 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.3 x 10^-12 (1.7 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/00661775. This circular is an official product of the Swift-XRT team.
GCN 18491 table
GRB_name GRB151027A
GCN_number 18491
Detection_method MITSuME
Circular_text TITLE: GCN CIRCULAR NUMBER: 18491 SUBJECT: GRB 151027A: MITSuME Akeno Optical observation DATE: 15/10/27 16:23:13 GMT FROM: Taketoshi Yoshii at Tokyo Tech Y. Yano, T. Yoshii, Y. Saito, Y. Tachibana, H. Ohuchi, S. Kurita, Y. Ono, T. Fujiwara, S. Harita, Y. Muraki, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 151027A (A. Maselli et al., GCN Circular #18478) 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 2015-10-27 09:13:52 UT ( 5.25 h after the burst). We detected the previously reported optical afterglow of GRB 151027A (WeiKang Zheng et al., GCN Circular #18479) in the g',Rc and Ic band. The measured magnitudes are listed below. T0+[sec] MID-UT T-EXP[sec] g' Rc Ic ------------------------------------------------------------------------------------------------------------------ 18928 09:34:24 2220 16.72+/-0.06 15.62+/-0.05 16.00+/-0.04 ------------------------------------------------------------------------------------------------------------------ T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used GSC2.3 catalog for flux calibration.
GCN 18492 table
GRB_name GRB151027A
GCN_number 18492
Detection_method Fermi GBM Det
t_trigger 3:58:24.030 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 18492 SUBJECT: GRB 151027A: Fermi GBM observation DATE: 15/10/27 16:31:56 GMT FROM: Hoi-Fung Yu at MPE Kilian Toelge, Hoi-Fung Yu (both MPE), and Charles A. Meegan (USRA) report on behalf of the Fermi GBM Team: "At 03:58:24.03 UT on 27 Oct 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 151027A (trigger 467611108 / 151027166), which was also detected by the Swift (Maselli et al. 2015, GCN 18478) The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 10 degrees. This burst was also independently detected by INTEGRAL SPI-ACS. The GBM light curve consists of three pulses with a duration (T90) of about 124 s (50-300 keV). The time-averaged spectrum from T0-2.048 s to T0+133.120 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.41 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 340 +/- 63 keV. The event fluence (10-1000 keV) in this time interval is (1.94 +/- 0.09)E-05 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+0.3840 s in the 10-1000 keV band is 11.37 +/- 0.34 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN 18493 table
GRB_name GRB151027A
GCN_number 18493
Detection_method Optical
redshift 0.3300
Circular_text TITLE: GCN CIRCULAR NUMBER: 18493 SUBJECT: GRB 151027A: GMG observation DATE: 15/10/27 16:43:32 GMT FROM: Jirong Mao at Yunnan Obs J. Zhang, J. Mao and J. Bai (YNAO) report: We observed the field of GRB 151027A (Maselli et al., GCN 18478) with the 2.4-meter optical telescope at Gao-Mei-Gu of Yunnan Observatories. Observations began at 11:34:08 UT, Oct 27, 2015, about 7.5 hr after the trigger. We obtained a low S/N spectrum. The feature of absorption line identified as MgII by Perley et al. (GCN 18487) is clearly shown, and redshift is 0.81. However, we noticed that some possible absorption lines might be identified as OVI and NaID, indicating a redshift of 0.33. We cannot have confirmation due to the low S/N of the spectrum. We also performed multi-band photometry and we obtained R~16.9 mag. Further analysis is ongoing.
GCN 18495 table
GRB_name GRB151027A
GCN_number 18495
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 18495 SUBJECT: GRB 151027A: Early RAPTOR Observations DATE: 15/10/27 18:16:09 GMT FROM: James Wren at LANL J. Wren, W.T. Vestrand, P. Wozniak, and H. Davis, of Los Alamos National Laboratory report: The RAPTOR network of robotic optical telescopes made follow-up observations of Swift trigger 661775 (Maselli et al., GCN 18478). Our narrow-field instruments in Los Alamos, NM USA, began imaging at 03:58:48.01 UT (23.86 s after the BAT trigger time). From the first frame we detected a bright optical counterpart at the location reported by UVOT. Starting with a magnitude of R~13.7 the RAPTOR telescopes measured a complex, fading lightcurve with seveal re-brightening intervals.
GCN 18496 table
GRB_name GRB151027A
GCN_number 18496
Detection_method Swift-BAT Det
ra 272.4980°
decl 61.3610°
Circular_text TITLE: GCN CIRCULAR NUMBER: 18496 SUBJECT: GRB 151027A: Swift-BAT refined analysis DATE: 15/10/27 18:51:53 GMT FROM: Amy Lien at GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), A. Maselli (INAF-IASFPA), T. Sakamoto (AGU), M. Stamatikos (OSU), 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 downlink, we report further analysis of BAT GRB 151027A (trigger #661775) (Maselli et al., GCN Circ. 18478). The BAT ground-calculated position is RA, Dec = 272.498, 61.361 deg which is RA(J2000) = 18h 09m 59.6s Dec(J2000) = +61d 21' 39.6" with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 18%. The mask-weighted light curve shows a complex structure with roughly two main pulses. The first pulse starts at ~T0, peaks at ~T+1 s, and ends at ~T+5 s. The second pulse starts at ~T+90 s, peaks at ~T+110 s, and ends at ~T+170 s. T90 (15-350 keV) is 129.69 +- 5.55 sec (estimated error including systematics). The time-averaged spectrum from T-0.74 to T+164.70 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.72 +- 0.05. The fluence in the 15-150 keV band is 7.8 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.20 sec in the 15-150 keV band is 6.8 +- 0.6 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/661775/BA/
GCN 18502 table
GRB_name GRB151027A
GCN_number 18502
Detection_method Swift-BAT Det
ra 272.4886°
decl 61.3515°
Circular_text TITLE: GCN CIRCULAR NUMBER: 18502 SUBJECT: GRB 151027A: UVOT Observations DATE: 15/10/28 01:04:14 GMT FROM: Mike Siegel at PSU/Swift MOC B. G. Balzer (PSU), M. H. Siegel (PSU) and A. Maselli (INAF-IASFPA) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 151027A 96 s after the BAT trigger (Maselli et al., GCN Circ. 18478). We confirm the source initially reported by Maselli et al. (GCN Circ. 18478) and since observed by numerous ground-based observatories (Zheng and Filippenko, GCN Circ. 18479; Elenin et al., GCN Circ. 18480; Perley and Cenko, GCN Circ. 18481; Xu et al., GCN Circ. 18485; Yano et al., GCN Circ. 18491; Wren et al., GCN Circ. 18495). We report a position of: RA(J2000) = +18h 09m 57.26s Dec(J2000) = +61d 21' 05.4" The light curve shows complex behavior, with marginal evidence of brightening after the initial finding chart, then fading with a decay slope of 0.6-0.8 over the first orbit. The second orbit magnitudes are consistent with no fading from those measured at the end of the first orbit while the third orbit shows significant fading. Preliminary detections 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 (fc) 95 245 147 14.52+-0.02 white 589 609 19 14.44+-0.04 white 762 782 19 14.71+-0.04 white 858 1008 147 14.81+-0.02 white 1161 1354 38 15.07+-0.04 white 1510 1529 19 15.23+-0.04 white 6449 6649 197 15.28+-0.01 white 23966 24662 677 17.14+-0.01 v 639 1579 116 15.12+-0.04 b 564 1505 97 15.37+-0.03 u 308 1479 323 14.00+-0.03 w1 688 1455 77 14.71+-0.05 m2 663 1598 88 14.98+-0.06 w2 615 1555 116 15.12+-0.05 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 18503 table
GRB_name GRB151027A
GCN_number 18503
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18503 SUBJECT: GRB 151027A: THO optical observations DATE: 15/10/28 02:54:58 GMT FROM: Veli-Pekka Hentunen at Taurus Hill Obs,A95 Veli-Pekka Hentunen, Markku Nissinen and Tuomo Salmi (Taurus Hill Observatory, Varkaus, Finland) report: We have detected GRB 151027A optical afterglow at Taurus Hill Observatory (A95) using Meade 16" ACF 0.40-m/8.0 telescope and SBIG ST-8XME CCD. The observations were started at 2015-10-27 17:11:39 (UT). Eight photometric R filter and eight photometric V filter images with 300 sec exposure time were taken. The afterglow was detected at the following position RA 18:09:56.72 and DEC +61:21:13.2. The following magnitudes were obtained from the observations using NOMAD1 1512-0243178 (R=13.200 and V=13.670) as a comparison star: Tmid(h)+T0 Filter Exp. time Mag Mag. Err. 13.393 R 4x300s 17.06 0.12 13.747 V 4x300s 17.56 0.25 14.103 R 4x300s 17.06 0.09 14.457 V 4x300s 17.49 0.10 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
GCN 18508 table
GRB_name GRB151027A
GCN_number 18508
Detection_method VLA Det
ra 272.4862°
decl 61.3536°
Circular_text TITLE: GCN CIRCULAR NUMBER: 18508 SUBJECT: GRB 151027A: VLA detection DATE: 15/10/28 08:47:38 GMT FROM: Tanmoy Laskar at UC Berkeley T. Laskar (NRAO / UC Berkeley), K. Alexander, and E. Berger (Harvard) report on behalf of a larger collaboration: "We observed GRB 151027A (Maselli et al.; GCN 18478) at multiple frequencies with the VLA beginning on 2015 October 27.95 UT (0.78 days after the burst). At a mean frequency of 21.8 GHz, we detect a bright radio source with a preliminary flux density of ~ 1.7 mJy at RA = 18:09:56.691 +/- 0.001 Dec = 61:21:13.03 +/- 0.02 consistent with the enhanced Swift/XRT position (Goad et al.; GCN 18482) and the optical position (Maselli et al.; GCN 18478, Zheng et al.; GCN 18479, Hentunen et al.; GCN 18503). Follow-up observations are planned. We thank the VLA staff for rapidly scheduling these observations."
GCN 18510 table
GRB_name GRB151027A
GCN_number 18510
Detection_method Optical
ra 272.4739°
decl 61.3492°
Circular_text TITLE: GCN CIRCULAR NUMBER: 18510 SUBJECT: GRB 151027A: LCOGT-McDonald afterglow observations DATE: 15/10/28 12:16:09 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy S. Dichiara (U. Ferrara, ICRANet), D. Kopac (U. Ljubljana), C. Guidorzi (U. Ferrara), S. Kobayashi (LJMU), A. Gomboc (U. Ljubljana) on behalf of a larger collaboration report: The 1-m LCOGT McDonald observatory began observing Swift GRB 151027A (Maselli et al. GCN 18478) on October 28, 01:29:27 UT (0.90 days after the burst trigger) with SDSS R and I filters. We clearly detect the optical afterglow (Maselli et al.; Zheng & Filippenko GCN 18479; Elenin et al. GCN 18480; Perley & Cenko GCN 18481; Xu et al. GCN 18485) with the following magnitudes: Mid Time Exposure Filter Magnitude (days) (s) ------------------------------------------------------- 0.90 5x120 R 16.87 +- 0.04 0.91 6x120 I 17.26 +- 0.05 ------------------------------------------------------- Calibration is done against nearby USNOB-1 star RA(J2000)=18:09:53.742, DEC(J2000)=+61:20:57.27, assuming R2=17.21 mag and I=17.17 mag. We note the presence of another USNOB-1 object at RA(J2000)=18:09:56.489, DEC(J2000)=+61:21:10.64, lying at 3.1 arcsec from the GRB afterglow.
GCN 18513 table
GRB_name GRB151027A
GCN_number 18513
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18513 SUBJECT: GRB 151027A: continued GMG observation DATE: 15/10/28 14:16:34 GMT FROM: Jirong Mao at Yunnan Obs J. Zhang, J. Mao and J. Bai (YNAO) report: We observed the field of GRB 151027A (Maselli et al., GCN 18478) with the 2.4-meter optical telescope at Gao-Mei-Gu of Yunnan Observatories. Observations began at 11:32:30 UT, Oct. 28, 2015, about 31.5 hr after the trigger. We clearly detected the afterglow of GRB 151027A. The magnitude was estimated as R=18.9 +/- 0.1 mag.
GCN 18515 table
GRB_name GRB151027A
GCN_number 18515
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18515 SUBJECT: GRB 151027A : Xinglong TNT optical observation DATE: 15/10/28 14:37:57 GMT FROM: L.P. Xin at NAOC L. P. Xin, X. F. Wang, J. Y. Wei, Y. L. Qiu, J. S. Deng, J. Wang, X. H. Han and C. Wu on behalf of EAFON report: We observed GRB 151027A (Maselli et al., GCN 18478) with Xinglong 0.8-m TNT telescope at 2015-10-27 and 2015-10-28. The optical afterglow (Maselli et al., GCN 18478; Zheng & Filippenko GCN 18479; Elenin et al., GCN 18480; Perley & Cenko GCN 18481; Xu et al, 18485; Zhang et al., GCN 18513) was clearly detected in our multi-band images. The brightness of the optical afterglow is decayed for about 2.5 mag in R-band during our observations as shown in follows: ============================== Date Time(UT) filter mag merr 2015-10-27 11:21:59 R 16.2 0.1 2015-10-28 11:04:00 R 18.7 0.1 ============================== Calibrated by the USNO B1.0 R2 mag More observations are encouraged. The message may be cited.
GCN 18516 table
GRB_name GRB151027A
GCN_number 18516
Detection_method Konus-Wind Det
t_trigger 3:58:24.154 UTC
redshift 0.8100
Circular_text TITLE: GCN CIRCULAR NUMBER: 18516 SUBJECT: Konus-Wind observation of GRB 151027A DATE: 15/10/28 14:43:29 GMT FROM: Dmitry Svinkin at Ioffe Institute S. Golenetskii, R. Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 151027A (Swift-BAT trigger #661775: Maselli et al., GCN Circ. 18478, Palmer et al., GCN Circ. 18496; Fermi GBM detection: Toelge et al., GCN Circ. 18492) triggered Konus-Wind at T0=14304.154 s UT (03:58:24.154). The burst light curve consists of at least three pulses with a total duration of ~120 s. The emission is seen up to ~5 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB151027_T14304/ As observed by Konus-Wind, the burst had a fluence of 1.42(-0.21,+0.37)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+0.432 s, of 2.22(-0.61,+0.62)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+131.328 s) is best fit in the 20 keV - 5 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.44(-0.21,+0.24) and Ep = 173(-46,+135) keV (chi2 = 78/77 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.0 (chi2 = 77/76 dof) The spectrum near the maximum count rate (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 2 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.96(-0.28,+0.32) and Ep = 91(-11,+14) keV (chi2 = 56/61 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.7 (chi2 = 56/60 dof) Assuming the redshift z=0.81 (Perley et al., GCN Circ. 18487) and a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27, and Omega_Lambda = 0.73, we estimate the following rest-frame parameters: the isotropic energy release E_iso is ~2.4x10^52 erg, the peak luminosity L_iso is ~7x10^51 erg/s, and the rest-frame peak energy of the time-integrated spectrum, Ep,i, is ~310 keV. All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN 18518 table
GRB_name GRB151027A
GCN_number 18518
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 18518 SUBJECT: GRB 151027A: T100 observations DATE: 15/10/28 17:37:17 GMT FROM: Eda Sonbas at NASA/GSFC E. Sonbas (Adiyaman Univ.), T. Guver (Istanbul Univ.), E. Gogus (Sabanci Univ.), O. Erece, M. Kocak, S. Eryilmaz, H. Kirbiyik (TUG) report on behalf of a larger collaboration We observed the field of Swift GRB 151027A (Maselli et al., GCN#18478) with the 1.0 meter T100 telescope (Bakirlitepe, TUBITAK National Observatory, Turkey), starting October, 27, 18:32:21 UT (~ 14.5 hours after the trigger). Observations were carried out in the R filter. The afterglow is detected in the R band images with an exposure time of 150 s. Using USNO-B1 star USNO-B1 1513-0237223 (R.A.=272.49, Dec=+61.37) in the field, the magnitudes of the OT were estimated as follows; t-t0 (hr) exp.(s) filt mag err (+/-) 14.56 150 R 16.8 0.06 14.61 150 R 17.2 0.08 Analysis of further observations with the same filter is ongoing. We thank to TUBITAK National Observatory for a partial support in using T100 telescope with project number 10CT100-95 and technical support.
GCN 18519 table
GRB_name GRB151027A
GCN_number 18519
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18519 SUBJECT: GRB 151027A: NOT optical and NIR observations DATE: 15/10/28 18:13:41 GMT FROM: Zach Cano at U of Iceland Z. Cano (U. Iceland), D. Malesani (DARK/NBI), Jussi Harmanen (NOT & U. Turku), Thomas Reynolds (NOT & U. Turku.), Pere Blay Serrano (IAC/NOT) and P. Jakobsson (U. Iceland) report on behalf of a larger collaboration: We observed the field of Swift GRB 151027A (Maselli et al., GCN Circ. 18478) with the Nordic Optical Telescope equipped with the StanCam (optical) and NOTCam (NIR) imagers, in filters BVRI and JHK, respectively. Observations started at 20:53 UT on 27 October 2015. The OT (Maselli et al.) is detected all filters. A summary of our observations follows: Filter t-t0 (hr) Mag +- Merr ----------------------------------------- B 17.94 21.4 +- 0.2 R 18.17 20.6 +- 0.1 I 18.28 19.2 +- 0.1 J 16.92 18.2 +- 0.1 H 17.38 18.3 +- 0.1 K 17.60 17.2 +- 0.2 The optical filters are calibrated to USNO-B1 and the NIR filters to 2MASS, where a single star that appeared in both catalogs was used for the zeropoint calculation. These magnitudes are not corrected for foreground extinction. When these extinguished magnitudes are converted to monochromatic fluxes (using the zeropoints from Fukugita et al. 1995; Hewett et al. 2006), a single power-law with an exponent of -1.25 provides an acceptable fit to the optical-to-NIR spectral energy distribution. ​
GCN 18521 table
GRB_name GRB151027A
GCN_number 18521
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18521 SUBJECT: GRB 151027A: SAO RAS optical observations DATE: 15/10/28 23:18:01 GMT FROM: Moskvitin Alexander at SAO RAS A. Moskvitin (SAO RAS, Russia), report on behalf of the larger GRB follow-up team: The field of the GRB 151027A (Maselli et al., GCNC #18478) was observed with the Zeiss-1000, 1 meter telescope of SAO RAS on the October, 28. The observations started 36.3 hours after the trigger. Two series of 300 sec. images in Rc band: 6 frames (16:13:57--16:56:20 UT) and 3 frames (17:32:15--17:50:33 UT) were obtained under the tolerable weather conditions. The OT is clearly detected in the stacked frames: # T_mid-T0,h exp,s R_mag 1 36.612 6 x 300 18.7 +/- 0.1 2 37.717 3 x 300 18.9 +/- 0.1 The photometry is based on nearby USNO-B1 stars proposed by A. Pozanenko (IKI RAS). The observations were provided with the help of the SAO RAS staff: V. Komarov, O. Spiridonova and R. Uklein.
GCN 18525 table
GRB_name GRB151027A
GCN_number 18525
Detection_method MAXI Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 18525 SUBJECT: GRB 151027A: MAXI/GSC detection DATE: 15/10/29 11:01:12 GMT FROM: H. Negoro at Nihon U. T. Masumitsu, H. Negoro, (Nihon U.), N. Kawai (Tokyo Tech), T. Sakamoto (AGU), S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Serino, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), T. Yoshii, Y. Tachibana (Tokyo Tech), A. Yoshida, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, R. Imatani (Osaka U.), M. Nakajima, K. Tanaka (Nihon U.), Y. Ueda, T. Kawamuro, T. Hori (Kyoto U.), Y. Tsuboi, S. Kanetou (Chuo U.), M. Yamauchi, D. Itoh (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Morii (ISM) report on behalf of the MAXI team: MAXI/GSC performed scanning observations at the region of GRB 151027A (Maselli et al. GCN 18478) for 48 sec each at the centroid time 03:38:56, 1168 s before the Swift trigger, and 05:11:32, 4388 s after the Swift trigger. No positive 4-10 keV flux was obtained at the former scan transit with the 3 sigma upper limit of 0.037 photons/cm2/s (~ 31 mCrab). At the latter scan transit, the 4-10 keV flux was 0.0166 +/- 0.0175 photons/cm2/s (~ 14 +/- 15 mCrab). The detection is not significant, but the flux is consistent with the interpolation from the Swift/XRT light curve (V. D'Elica et al. #18509).
GCN 18533 table
GRB_name GRB151027A
GCN_number 18533
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18533 SUBJECT: GRB 151027A: Optical counterpart detection DATE: 15/10/29 21:34:24 GMT FROM: Valentyna Golovnya at Main Astro Obs,Kyiv Yu. Protsyuk (RI NAO), O. Kovalchuk (RI NAO) report: We observed the field of the Swift GRB 151027A (Maselli et al. GCN 18478) with 0.5-m telescope Mobitel KT-50 of Nikolaev observatory with Alta-U9000 CCD-camera with R filter in robotic mode from Oct., 28 (UTC) 20:34:16 till 20:59:59. We obtained 19 unfiltered images of 60 s exposure and calculated coordinates and magnitudes of all detected objects in UCAC4 system. We don't detect any optical counterpart of GRB 151027A (Maselli et al. GCN 18478; Zheng and Filippenko, GCN 18479) in coordinates near (J2000) 18 09 56 +61 21 12 up to ~17.2- 17.5 m . After that we filtered all images and detected optical counterpart in 6 images in coordinates (J2000) 18 09 56.680 (SD=0.s081) +61 21 12.08 (SD=0."63) with brightness near 18.3m (SD=0.3m)
GCN 18537 table
GRB_name GRB151027A
GCN_number 18537
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18537 SUBJECT: GRB 151027A: Continued P60 Monitoring DATE: 15/10/30 14:37:08 GMT FROM: S. Bradley Cenko at NASA/GSFC S. B. Cenko (NASA-GSFC) and D. A. Perley (DARK/NBI) report on behalf of a larger collaboration: We have continued to image the optical afterglow of GRB151027A (Maselli et al., GCN 18478) with the robotic Palomar 60-inch telescope (see Perley et al., GCN 18481). We report the following r-band photometry, calibrated with respect to nearby point sources from the APASS survey: t_mid time since burst (d) Magnitude 2015-10-29T02:14:14 1.93 19.63 +/- 0.04 2015-10-30T02:02:28 2.92 20.48 +/- 0.08 This implies a relatively steep power-law decay index of ~ 1.9 at these times. Continued observations are planned.
GCN 18539 table
GRB_name GRB151027A
GCN_number 18539
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18539 SUBJECT: GRB 151027A: optical follow-up observations DATE: 15/10/31 06:39:13 GMT FROM: Patrick Wiggins at Wiggins Obs P. Wiggins reports: Observed GRB 151027A with a .35-meter optical telescope at my home observatory, IAU 718, on 2015 October 27 from 0433 to 0732 UTC using a clear filter and obtained the following: GRB Countpart: 18h 09m 56.71s +61d 21m 12.78s Reference One: 18h 10m 05.68s +61d 23m 14.97s Reference Two: 18h 09m 51.53s +61d 22m 48.87s Julian Date Date Ref. C Ref. K Var. V C-K Differential Mid Exposure yyyy-mm-dd.ddddd Raw Mag. Raw Mag. Raw Mag. Differ. Mag. -------------- ---------------- --------- --------- --------- --------- ------------ 2457322.689715 2015 10 27.18972 -2.937 -3.111 -1.085 0.174 15.051 2457322.692866 2015 10 27.19287 -2.433 -2.622 -1.355 0.190 14.278 2457322.700101 2015 10 27.20010 -2.732 -2.925 -1.433 0.192 14.499 2457322.703174 2015 10 27.20317 -2.921 -3.112 -1.605 0.191 14.516 2457322.724392 2015 10 27.22439 -2.909 -3.088 -1.391 0.180 14.718 2457322.758285 2015 10 27.25829 -2.949 -3.142 -1.151 0.193 14.998 2457322.786495 2015 10 27.28649 -2.906 -3.085 -0.916 0.180 15.189 2457322.801286 2015 10 27.30129 -2.901 -3.108 -0.722 0.207 15.379 2457322.814370 2015 10 27.31437 -2.879 -3.079 -0.406 0.201 15.673 END
GCN 18552 table
GRB_name GRB151027A
GCN_number 18552
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18552 SUBJECT: GRB 151027A: Correction to GCN 18519 DATE: 15/11/02 19:12:53 GMT FROM: Zach Cano at U of Iceland ​Z. Cano (U. Iceland) reports on behalf of a larger collaboration: Upon further investigation, it was discovered that the magnitudes given in GCN Circ. 18519 are incorrect. The presented photometry was not for the optical and NIR afterglow of GRB 151027A, but rather the fainter object that is 3.1 arcsec SW of the afterglow (Dichiara et al. GCN Circ. 18510). A revised summary of the NOT observations follows: Filter t-t0 (hr) Mag +- Merr ----------------------------------------- B 17.94 18.2 +- 0.1 R 18.17 17.9 +- 0.1 I 18.28 17.4 +- 0.1 J 16.92 16.4 +- 0.1 H 17.38 15.5 +- 0.1 K 17.60 15.1 +- 0.1 The optical filters are calibrated to USNO-B1 and the NIR filters to 2MASS, where a single star that appears in both catalogs was used for the zeropoint calculation. These magnitudes are not corrected for foreground extinction. When these extinguished magnitudes are converted to monochromatic fluxes (using the zeropoints from Fukugita et al. 1995; Hewett et al. 2006), a single power-law with an exponent of -0.8 provides a good fit to the optical-to-NIR spectral energy distribution. My apologies for the confusion.​
GCN 18555 table
GRB_name GRB151027A
GCN_number 18555
Detection_method Fermi LAT Other
redshift 0.8100
Circular_text TITLE: GCN CIRCULAR NUMBER: 18555 SUBJECT: GRB 151027A: the missing GeV component DATE: 15/11/03 18:21:32 GMT FROM: Remo Rufinni at ICRA R. Ruffini, Y. Aimuratov, U. Barres, R. Belvedere, C.L. Bianco, M. Enderli, M. Kovacevic, R. Moradi, M. Muccino, A. Penacchioni, G.B. Pisani, J.A. Rueda, Y. Wang report: From its overlapping [1] with GRB 090618, the prototype of binary-driven hypernovae (BdHNe), we can assert that this GRB belongs to the class of long GRBs originating in a binary system composed of a carbon-oxygen core and a companion neutron star (Rueda & Ruffini, 2012; Fryer et al. 2014). At the redshift of z=0.81 (Perley et al, GCN 18487) the isotropic energy is Eiso ~ 4x10^(52) erg and the rest-frame spectral peak energy is Ep,i ~ 615 keV (Toelge et al., GCN 18492). A SN should appear after 13-15 days in rest-frame, namely between November 19th and November 23rd. The exceptional feature of GRB 151027A is that, even if it belongs to the BdHN class, there is no high energy emission associated as of today although it was in the Fermi-LAT field of view (Toelge et al., GCN 18492). If confirmed this can be of support to probe the angular distribution of the high energy emission. Additional data in all wavelengths are requested for this most peculiar source. [1] http://www.icranet.org/documents/GRB151027A.pdf
GCN 18558 table
GRB_name GRB151027A
GCN_number 18558
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18558 SUBJECT: GRB 151027A: Mt. Terskol observatory optical observation DATE: 15/11/04 10:08:22 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Kozlov (IC AMER, NASU), M. Andreev (Terskol Branch of INASAN), E. Mazaeva (IKI), A. Sergeev (Terskol Branch of INASAN), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 151027A (Maselli et al., GCN 18478) with Zeiss-600 telescope of Mt. Terskol observatory in R-filter starting on Oct. 28 (UT) 21:23:11. We obtained several images in R-filter. The afterglow (Maselli et al., GCN 18478; Zheng and Filippenko, GCN 18479) is clearly detected in a combined image. The photometry of the combined image is following Date UT start t-T0 Filter Exp. OT Err (mid, days) (s) 2015-10-28 21:23:11 1.7431 R 25*120 19.56 0.12 The photometry is based on nearby USNO-B1.0 stars USNO-B.1_id R2 1513-0237223 16.66 1513-0237170 15.58 1513-0237251 16.81 1513-0237270 16.78
GCN 18559 table
GRB_name GRB151027A
GCN_number 18559
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18559 SUBJECT: GRB 151027A: Mondy optical observations DATE: 15/11/04 17:58:29 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), A. Volnova (IKI), E. Klunko (ISTP), I. Korobtsev (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the Swift GRB 151027A (Maselli et al., GCN 18478) with AZT-33IK telescope of Sayan observatory (Mondy) on several epochs. We obtained images in R-filter on Oct., 27-- Nov., 1 . The afterglow (Maselli et al., GCN 18478; Zheng and Filippenko, GCN 18479) is clearly detected in each epoch. Coordinates of the afterglow are (J2000) 18 09 56.66 +61 21 13.0 with uncertainties of 0.3 arcsec in each coordinate. We also detected the USNO-B1.0 source mentioned in GCN 18510 (Dichiara et al.) in a position (J2000) 18 09 56.44 +61 21 10.8 with uncertainties of 0.3 arcsec in each coordinate. Preliminary photometry of the afterglow on October-29 -- November, 1 is following Date UT start t-T0 Filter Exp. OT Err. (mid, days) (s) 2015-10-29 13:18:41 2.4082 R 55*60 19.84 0.05 2015-10-30 12:11:18 3.3736 R 78*60 20.32 0.06 2015-10-31 12:47:18 4.3958 R 41*120 21.25 0.07 2015-11-01 12:28:18 5.3694 R 19*120 21.50 0.12 The photometry is based on nearby USNO-B1.0 stars USNO-B.1_id R2 1513-0237223 16.66 1513-0237170 15.58 1513-0237251 16.81 1513-0237270 16.78 Late time photometry could be influenced by the nearby USNO-B1.0 source. The overall light curve of our observations as well as photometry reported in GCNs 18480, 18521,18558 can be found in http://grb.rssi.ru/GRB151027A/GRB151027A_lc.png
GCN 18567 table
GRB_name GRB151027A
GCN_number 18567
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18567 SUBJECT: GRB 151027A: Hankasalmi optical observations DATE: 15/11/08 09:04:54 GMT FROM: Arto Oksanen at Nyrola Obs., Finland Arto Oksanen (Hankasalmi Obs., Hankasalmi, Finland) reports the following observations of GRB 151027A (Maselli et al. 2015, GCN Circular #18478; Zheng et al. 2015, GCN Circular #18479, and many subsequent Circulars) to the AAVSO High Energy Network: A. Oksanen observed the location of GRB 151027A using the Hankasalmi Observatory 0.4-m Richey-Chretien telescope using an SBIG STL-1001E camera. Time-series images were obtained with both Rc and clear filters, with fifty 60-second frames obtained in each filter. Clear filtered images were obtained between 16:27:07 UT and 22:01:23 UT on 2015 October 27, and Rc-filtered images were obtained between 18:59:58 and 21:45.04 UT. Photometry was performed using an ensemble of comparison stars with APASS photometry available from AAVSO VSP (www.aavso.org/vsp). The afterglow is detected in both Rc- and clear-filtered observations, with evidence of fading between the start and end of the observing run. Photometry of co-added groups of images yields the following: Clear filter: t-t0(d) m(CR) err(CR) 0.5235 16.872 0.030 0.5334 16.816 0.030 0.6531 17.160 0.044 0.6644 17.322 0.047 0.7468 17.575 0.065 Rc filter: t-t0(d) m(R) err(R) 0.6365 17.257 0.058 0.6848 17.544 0.074 0.7353 17.580 0.118 These magnitudes of GRB 151027A are consistent with other magnitudes obtained at similar epochs of this burst (e.g. Hentunen et al. GCN Circular #18503; Sonbas et al. #18518).
GCN 18575 table
GRB_name GRB151027A
GCN_number 18575
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18575 SUBJECT: GRB 151027A: continued Mondy optical observations DATE: 15/11/10 19:10:04 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), E. Klunko (ISTP), A. Volnova (IKI), I. Korobtsev (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We continue observations (GCN 18559) of the Swift GRB 151027A (Maselli et al., GCN 18478) with AZT-33IK telescope of Sayan observatory (Mondy). We obtained images in R-filter on Nov., 4, 5, 7-9. In a combined image obtained on Nov. 7 we clearly detect a galaxy which coincide with the object 1513-0237216 of USNO-B1.0 catalog. The object was also mentioned in GCN 18510 (Dichiara et al.) and GCN 18559 (Mazaeva et al.) The finding chart can be found in http://grb.rssi.ru/GRB151027A/GRB151027A_20151107_AZT33IK_host.png The afterglow (Maselli et al., GCN 18478; Zheng and Filippenko, GCN 18479) is not well detected. The afterglow might overlap with North-East wing of the galaxy. The galaxy could be suggested as a host galaxy of GRB 151027A. Preliminary photometry of the galaxy is R= 20.60+/-0.04 at November, 7. The photometry is based on nearby USNO-B1.0 stars referenced in GCN 18559.
GCN 18608 table
GRB_name GRB151027A
GCN_number 18608
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 18608 SUBJECT: GMRT radio detection of GRB 151027A DATE: 15/11/16 11:43:16 GMT FROM: Poonam Chandra at TIFR Poonam Chandra (NCRA-TIFR) and A. J. Nayana (NCRA-TIFR) reports: We carried out Giant Metrewave Radio Telescope (GMRT) observations of GRB 151027A (GCN Circ. 18478) at 1390 MHz band on 2015 Nov 15.19 UT. We detect the radio afterglow of the GRB in the Swift error circle (GCN Circ. 18482). The 1390 MHz band flux density of the afterglow is 312+/-64 uJy. Map rms is 37 uJy. Further observations are planned. We thank GMRT staff for making these observations possible. -- _________________________________________ Poonam Chandra National Centre for Radio Astrophysics Tata Institute of Fundamental Research Pune University Campus, Ganeshkhind Pune 411007, Maharashtra, INDIA Phone: +91 20 2571 9290 Fax: +91 20 2569 7257 Email: poonam@ncra.tifr.res.in Web: www.ncra.tifr.res.in:8081/~poonam/ _________________________________________
GCN 18609 table
GRB_name GRB151027A
GCN_number 18609
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18609 SUBJECT: GRB151027A; Optical observations DATE: 15/11/16 12:16:29 GMT FROM: G.C. Anupama at IIA,Bangalore We observed the field of GRB 151027A (Maselli et al., GCN 18478) using the 2m Himalayan Chandra Telescope of Indian Astronmical Observatory, Hanle, India. The GRB field was observed in Bessells R band, during 14:56 UT to 16:20 UT on 2015-10-27. We obtained 20 frames, each of 150 seconds exposure time. The optical afterglow of GRB 151027A (e.g., Maselli et al., GCN 18478; Zheng & Filippenko, GCN 18479; Elenin et al., GCN 18480; Perley & Cenko, GCN 18481) is clearly detected in each image. The measured magnitudes, calibrated using nearby USNO B1.0 (R2 magnitudes) stars are listed below. --------------------------------------------------------------------- Time (UT start) Filter Mag error 14:56 R 16.60 0.06 15:36 R 16.67 0.07 16:20 R 16.86 0.08 ----------------------------------------------------------------------- This message may be cited. D.K. Sahu and G.C. Anupama (Indian Institute of Astrophysics, Bengaluru)
GCN 18616 table
GRB_name GRB151027A
GCN_number 18616
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 18616 SUBJECT: GRB 151027A: SAO RAS and Mt. Terskol observations DATE: 15/11/18 12:41:05 GMT FROM: Moskvitin Alexander at SAO RAS A. S. Moskvitin (SAO RAS), I. V. Sokolov (Terskol Branch of INASAN) report on behalf of larger GRB follow-up team. We observed the field of GRB 151027A twice: with 2-m Zeiss-2000 + FLI CCD (Mt. Terskol) and 1-m Zeiss-1000 + EEV 42-40 CCD (SAO RAS) on November 6 and 12 respectively (T-T0 = 10.5 and 16.5 days). We have obtained 10x300 and 24x300 sec. frames in R band. We do not detect the GRB OT (Maselli et al., GCNC #18478) down to the limiting magnitude R_lim = 22.8 in both stacked images. As the standard stars we used USNO-B1 objects from GCNCs #18521, 18558 and 18559. We should note that nearby USNO-B1 source reported by S. Dichiara et al. (GCNC #18510) and E. Mazaeva et al. (GCNC #18559) is clearly detected in our images.
GCN 18620 table
GRB_name GRB151027A
GCN_number 18620
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 18620 SUBJECT: 610 MHz detection of GRB 151027A with the GMRT DATE: 15/11/19 10:52:47 GMT FROM: Poonam Chandra at TIFR Poonam Chandra (NCRA-TIFR) and A. J. Nayana (NCRA-TIFR) reports: We carried out Giant Metrewave Radio Telescope (GMRT) observations of GRB 151027A (GCN Circ. 18478) at 610 MHz band on 2015 Nov 19.19 UT. We detect the radio afterglow of the GRB in the Swift error circle (GCN Circ. 18482). The 610 MHz band flux density of the afterglow is 522+/-94 uJy. Map rms is 56 uJy. Further observations are planned. We thank GMRT staff for making these observations possible. -- _________________________________________ Poonam Chandra National Centre for Radio Astrophysics Tata Institute of Fundamental Research Pune University Campus, Ganeshkhind Pune 411007, Maharashtra, INDIA Phone: +91 20 2571 9290 Fax: +91 20 2569 7257 Email: poonam@ncra.tifr.res.in Web: www.ncra.tifr.res.in:8081/~poonam/ _________________________________________
GCN 18635 table
GRB_name GRB151027A
GCN_number 18635
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 18635 SUBJECT: GRB 151027A: Maidanak optical observations DATE: 15/11/22 21:48:09 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Pozanenko (IKI), E. Mazaeva (IKI), A. Volnova (IKI), O. Burhonov (UBAI) report on behalf of larger GRB follow-up collaboration: We observed the Swift GRB 151027A (Maselli et al., GCN 18478) with AZT-22 telescope of Maidanak observatory equipped with SNUCAM in R filter. We obtained several images in R-filter on Oct., 30, Nov., 6 and Nov., 9 under mean FWHM of about 0.9". The afterglow (Maselli et al., GCN 18478; Zheng and Filippenko, GCN 18479) is clearly detected in each epoch. The afterglow is well separated from nearby source (Dichiara et al.GCN 18510; Mazaeva et al., GCN 18559). Preliminary photometry of the afterglow is following Date UT start t-T0 Filter Exp. OT Err. (mid, days) (s) 2015-11-06 15:04:07 10.474 R 10*300 23.30 0.24 2015-11-09 14:06:04 13.443 R 10*300 23.33 0.20 The photometry is based on nearby USNO-B1.0 stars USNO-B.1_id R2 1513-0237223 16.66 1513-0237251 16.81 1513-0237270 16.78 A preliminary light curve of the afterglow can be found in http://grb.rssi.ru/GRB151027A/GRB151027A_lc.png At this time it is unclear what is a reason of flattening of the light curve at 11-13 days. It might be SN signature or it is continuing bumps of the light curve previously seen at least on ~ 1.3 days and ~3 days.