- GCN Circular #16360
L. P. Singer (Caltech), M. M. Kasliwal (Carnegie
Observatories/Princeton), and S. B. Cenko (NASA/GSFC) report on
behalf of the intermediate Palomar Transient Factory (iPTF)
collaboration:
Fermi GBM reported trigger 423717114 at 2014-06-06 03:11:51.86 UT. We
have searched for optical counterparts using the Palomar 48-inch
Oschin telescope (P48). Based on the final Fermi GBM localization, we
observed 10 fields covering 73 deg2, with an estimated 56% chance of
containing the true location of the event.
Sifting through candidate variable sources using image subtraction
and standard iPTF vetting procedures, we detected several optical
transients.
iPTF14bfu has no previous detections in iPTF from 2013-05-23 through
2013-10-13, and no obvious host associations. From 4.3 to 5.5 hours
after the burst, it faded from r = 19.89 +/- 0.10 to 20.32 +/- 0.14
mag, fitting a power law of alpha = -1.6 +/- 0.7 relative to the time
of the GBM trigger. It is at the coordinates:
RA(J2000) = 21h 52m 29.97s (328.124877 deg)
Dec(J2000) = +32d 00' 50.6" (+32.014053 deg)
iPTF14bfw is coincident with the faint galaxy SDSS
J220322.02+291451.1. It was at r = 19.96 +/- 0.06 and possibly
fading, at the coordinates:
RA(J2000) = 22h 03m 22.04s (330.841830 deg)
Dec(J2000) = +29d 14' 51.8" (+29.247730 deg)
iPTF14bgc, was at r = 18.44 +/- 0.02 and possibly fading. It is
coincident with a r = 21.07 +/- 0.08 mag point source in our coadded
reference image composed of exposures from 2013-07-31 through
2013-09-24. It is at the coordinates:
RA(J2000) = 21h 45m 36.14s (326.400599 deg)
Dec(J2000) = +32d 08' 57.9" (+32.149426 deg)
iPTF14bga, was at r = 19.75 +/- 0.06 mag and possibly fading. It is
coincident with a r = 20.42 +/- 0.17 mag point source in our
reference image composed of exposures from 2011-07-29 through
2011-10-20. It is a the coordinates:
RA(J2000) = 22h 12m 43.78s (333.182423 deg)
Dec(J2000) = +33d 39' 43.7" (+33.662146 deg)
Further observations are planned, and are encouraged to determine
the nature of these candidates and determine if any of them are
indeed associated with the Fermi trigger.
The diagram
http://www.its.caltech.edu/~lsinger/iptf/Fermi423717114.pdf shows the
locations of our candidates and the ten P48 fields in relation to the
Fermi GBM 1- and 2-sigma statistical+systematic contours.
We thank the Fermi-GBM team for sharing their detailed localizations
with us.
- GCN Circular #16362
D. A. Perley and L. Singer (Caltech) report on behalf of a larger
collaboration:
We re-imaged the same ten P48 fields near the center of the error circle
of Fermi trigger 423717114 (Singer et al., GCN 16360) between 09:28:30
through 09:42:30 UT on the night of 2014-06-07. iPTF14bfw and iPTF14bga
have not faded relative to our observations during the previous night.
For iPTF14bgc, we measure R = 20.68 +/- 0.21, consistent with the
point-like counterpart in our reference images but significantly fainter
than the previous night. A power law fit to the decay gives a temporal
index of alpha = -1.1 +/- 0.1.
We do not detect iPTF14bfu in our P48 image with a limiting magnitude of
R ~ 21.1. Further imaging was obtained with the Palomar 60-inch
telescope on two epochs, starting at 07:47:45 and 10:47:31,
respectively. We acquired a series of seven 180-second images in r-band
and five 180-second images in i-band in the first epoch, and a series of
seven 180-second images in r-band during the second epoch.
We detect the transient in a combined stack of all exposures in each
band/epoch. Calibrating relative to USNO-B1.0 stars in the image, we
measure magnitudes of:
r = 21.1 +/- 0.2 (t_mid = 28.78 hr)
i = 21.0 +/- 0.3 (t_mid = 29.12 hr)
r = 21.4 +/- 0.2 (t_mid = 31.78 hr)
Relative to the magnitudes presented by Singer et al., these
observations suggest an average temporal index of only alpha~-0.5, much
slower than observed during the first night. Further observations are
ongoing.
- GCN Circular #16363
E. Burns (UAH) reporting on behalf of the Fermi GBM Team:
"At 03:11:51.86 UT on 06 June 2014, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 140606B (trigger 423717114 / 140606133).
The on-ground calculated location, using the GBM trigger
data, is RA = 327.9, DEC = +33.7 (J2000 degrees,
equivalent to 21 h 51 m, 33 d 41 '), with an uncertainty
of 1.00 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 66 degrees.
The optical afterglow candidates reported by iPTF (Singer et al.
GCN 16360) lie within the 1-sigma (statistical and systematic)
uncertainty regions surrounding the GBM localization.
The GBM light curve shows one long peak with a
noisy tail with a duration (T90) of about 23.6 s (50-300 keV).
The time-averaged spectrum from T0-3.0 s to T0+12.3 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.22 +/- 0.04 and
the cutoff energy, parameterized as Epeak, is 473.00 +/- 82.60 keV
The event fluence (10-1000 keV) in this time interval is
(9.018 +/- 0.369)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.58 s in the 10-1000 keV band is
13.31 +/- 0.37 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
- GCN Circular #16365
D. A. Perley, Y. Cao (Caltech), M. Kasliwal (Carnegie), and E. Kirby
(UCI) report:
On the night of 2014-06-07 starting at 19:16 (UT) we acquired two 900
second optical spectra of iPTF14bfu (Singer et al., GCN 16360), an
optical transient in the error circle of GRB 140606B / Fermi 432717114
(Burns et al., GCN 16360), with the DEIMOS spectrograph on the Keck II
10 meter telescope.
In the reduced spectrum of this object we identify emission lines from
OII, OIII (5007) and H-alpha, as well as absorption features from Ca II
(H+K), at a consistent redshift of z = 0.384. A serendipitous galaxy
offset by ~2 arcseconds (10 kpc) along the slit shows the same emission
lines at identical redshift but no detectable continuum.
Given this redshift, the high luminosity inferred for the optical
transient at the time of the initial detection (absolute magnitude ~
-21.7) favors the association of this source as the optical afterglow of
GRB 140606B.
- GCN Circular #16366
V. Mangano (PSU), P.A. Evans and M.R. Goad (U. Leicester) report
on behalf of the Swift-XRT team:
We have analysed 5 ks of XRT data for the Fermi/GBM-detected burst:
GRB 140606B, from 184.4 ks to 192.6 ks after the Fermi/GBM trigger.
The data are entirely in Photon Counting (PC) mode.
Using 4979 s of XRT Photon Counting mode data and 4 UVOT
images, 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 =
328.12501, 32.01458 which is equivalent to:
RA (J2000): 21 52 30.00
Dec (J2000): +32 00 52.5
with an uncertainty of 2.3 arcsec (radius, 90% confidence).
This position is a 5.2 arcsec from source iPTF 14bfu from
GCN Circular 16360.
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).
We cannot determine at the present time whether the source is fading.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020384.
This circular is an official product of the Swift-XRT team.
- GCN Circular #16367
V. Toy (UMD), J. Capone (UMD), D. Kocevski (NASA-GSFC), S.B. Cenko
(NASA-GSFC), A. Cucchiara (NASA-GSFC), E. Troja (NASA-GSFC), A. Kutyrev
(NASA-GSFC), S. Veilleux (UMD), and S. Gezari (UMD) report on behalf of a
larger collaboration:
We observed the field of GRB140606B/iPTF14bfu (Singer et al., GCN 16360,
Fermi 432717114, Burns et al. GCN 16363) with the Large Monolithic Imager
(LMI) on the 4.3m Discovery Channel Telescope (DCT) at Happy Jack, AZ from
2014/06/08 9:05 to 2014/06/08 09:41 UTC (starting 29.9 hours after the
Fermi trigger). A source is clearly detected at the location of the
optical afterglow in g', r', i', and z'. Using nearby point sources from
APASS for calibration we obtain the following detections:
g' = 22.8 +/- 0.04
r' = 22.2 +/- 0.04
i' = 22.1 +/- 0.05
z' = 22.1 +/- 0.08
These magnitudes are reported in the AB system and are not corrected for
Galactic extinction in the direction of the GRB. Further observations are
planned.
We thank the staff of the Discovery Channel Telescope for assistance with
these observations.
- GCN Circular #16368
M. M. Chester (PSU) and V. Mangano (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT observed the field of the Fermi/GBM-detected burst GRB 140606B beginning 184.4 ks after the Fermi/GBM trigger (Burns et al. GCN Circ. 16363). No source consistent with iPTF14bfu, the optical counterpart proposed by Singer et al. (GCN Circ. 16360) and Perley et al. (GCN Circ. 16365), 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) are given in the following table:
Filter T_start(s) T_stop(s) Exp(s) Mag
u 185271 191914 1693 >21.1
b 186146 192611 1495 >20.9
v 184395 191055 1693 >20.6
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.12 in the direction of the burst
(Schlegel et al. 1998).
- GCN Circular #16369
K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team,
S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks, D. Svinkin, and
T. Cline on behalf of the Konus-Wind team, and
V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa, and A. Goldstein,
on behalf of the Fermi GBM team, report:
The long-duration GRB 140606B has been observed by Fermi (Burns GCN
Circ. 16363), Konus-Wind, and MESSENGER (GRNS), so far, at about 11512 s
UT (03:11:52).
We have triangulated it to a preliminary, 3 sigma error box whose
coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
327.109 (21h 48m 26s) +33.047 (+33d 02' 50")
Corners:
321.995 (21h 27m 59s) +37.333 (+37d 19' 58")
321.768 (21h 27m 04s) +38.102 (+38d 06' 06")
332.033 (22h 08m 08s) +27.958 (+27d 57' 29")
332.250 (22h 09m 00s) +26.987 (+26d 59' 14")
---------------------------------------------
The error box area is 5.53 sq. deg, and its maximum
dimension is 14.18 deg (the minimum one is 0.414 deg).
This box may be improved.
Only two of the reported optical sources (Singer et al. GCN Circ.
16360), namely iPTF14bfw and iPTF14bfu, are inside the box, and
iPTF14bfw was found to be a constant source (Perley and Singer, GCN
Circ. 16362).
The distance between the narrowest annulus (GBM-MESSENGER annulus with 3
sigma half width of 0.207 deg) center line and the iPTF14bfu (the fading
source) is 2 arcsec, strengthening the association of the transient
and the GRB.
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB140606_T11511/IPN/
Details of the Konus-Wind observation will be given in a forthcoming GCN
Circular.
- GCN Circular #16373
V. Mangano and D.N. Burrows (PSU)
on behalf of the Swift-XRT team:
Swift XRT performed a second 5 ks ToO observation of the field of
GRB 140606B on June 09 2014, starting about 273.8 ks since the
Fermi/GBM trigger.
The XRT source reported in Mangano et al. (GCN Circ. 16366) is still
detected. The X-ray position, with a 90% error radius of 2.3 arcsec,
is 1.9 arcsec from the optical afterglow candidate iPTF14bfu
proposed by Singer et al. (GCN Circ. 16360).
The XRT light curve shows marginal evidence of decay. Further observations
are planned to confirm it.
This circular is an official product of the Swift-XRT team.
- GCN Circular #16374
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration GRB 140606B (Fermi-GBM detection: Burns, GCN 16319;
IPN triangulation: Golenetskii et al., GCN 16369) triggered Konus-Wind
at T0=11510.769 s UT (03:11:50.769).
The burst light curve shows a single pulse with a duration of ~8 s.
The emission is seen up to ~5 MeV.
As observed by Konus-Wind, the burst had a fluence of
6.6(-0.5,+0.5)x10^-6 erg/cm2, and a 64-ms peak flux, measured from
T0+0.752 s, of 2.9(-0.7,+0.7)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst (measured from T0 to T0+8.448 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 = -0.60(-0.18,+0.20),
and Ep = 254(-27,+33) keV (chi2 = 78/73 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.9
(chi2 = 78/72 dof).
Assuming the redshift z=0.384 (Perley et al., GCN 16365)
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 2.5(-0.2,+0.2)x10^51 erg,
the peak luminosity L_iso is 1.5(-0.4,+0.4)x10^51 erg/s,
and the rest-frame peak energy, Ep,i, is 352(-37,+46) keV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB140606_T11510/
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
- GCN Circular #16377
V. Toy (UMD), A. Cucchiara (NASA-GSFC), J. Capone (UMD),
D. Kocevski (NASA-GSFC), S.B. Cenko (NASA-GSFC),
E. Troja (NASA-GSFC), A. Kutyrev (NASA-GSFC), S. Veilleux (UMD),
and S. Gezari (UMD) report on behalf of a larger collaboration:
We report that in GCN 16367 we mistakenly estimated the time post-burst
for our DCT observations.
The optical transient was observed from 2014/06/08 9:05 to 2014/06/08
09:41 UTC, which corresponds to 53.9 hours after the GRB discovery
(GCN 16363) and not 29.9 hours as reported.
We apologize for any confusion this might have caused and we thank
Dan Perley for pointing out this inconsistency.
- GCN Circular #16387
D. A. Perley (Caltech), M. Kasliwal (Carnegie), L. P. Singer, Y. Cao
(Caltech), and K. Tinyanont (Harvey Mudd) report:
Beginning at 12:57 UT on 2014-06-08 we observed the field of iPTF14bfu
(Singer et al., GCN 16360), the optical counterpart of GRB 140606B
(Burns et al., GCN 16363), using the imaging mode of MOSFIRE on the Keck
I 10m telescope. A sequence of nine 23-second images was acquired in the
Ks filter.
Calibrating relative to 2MASS stars in the image, we measure a magnitude of:
Ks = 19.50 +/- 0.06 (Vega, or Ks = 21.34 AB)
at a mid-time of 2.411 days after the initial trigger.
We also measure an improved astrometric position (relative to 2MASS) of:
21:52:29.961 +32:00:50.66 (J2000, +/- 0.2")
- GCN Circular #16398
A. Volnova (IKI), R. Inasaridze (AAO), O. Kvaratskhelia (AAO), V.
Ayvazian (AAO), Yu. Krugly (IA KhNU), I. Molotov (KIAM), A. Pozanenko
(IKI) report on behalf of larger GRB follow-up collaboration:
We observed a field of the GBM GRB 140606B / iPTF 14bfu (Singer et al.,
GCN 16360) with AS-32 (0.7m) telescope of Abastumani Observatory
starting on June, 07 (UT) 21:40:06. We obtained several unfiltered
frames with exposure of each frame of 120 s. The optical transient is
well detected on the stacked image.
A photometry is based on nearby USNO-B1.0 stars:
date UT start t-T0 Filter Exp. OT err
(mid, days) (s)
2014-06-07 21:40:06 1.82039 None 46*120 21.95 +/- 0.20
- GCN Circular #16403
A. Volnova (IKI), E. Klunko (ISTP), M. Eselevich (ISTP), I. Korobtsev
(ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up
collaboration:
We observed a field of the GBM GRB 140606B / iPTF 14bfu (Singer et al.,
GCN 16360) with with AZT-33IK telescope of Sayan observatory (Mondy). We
obtained several images on June, 08 (UT) 17:17:29 with exposure of each
frame of 120 s. The optical transient Singer et al., GCN 16360) is well
detected on the stacked image. A photometry is based on nearby USNO-B1.0
stars:
date UT start t-T0 Filter Exp. OT
(mid, days) (s)
2014-06-08 17:17:29 2.62892 R 60*120 22.00+/-0.12
The finding chart can be found in
http://grb.rssi.ru/GRB140606B/grb140606B_AZT33IK_R_fc.png
The light curve based on published photometry in r, R and unfiltered
observations (GCNs 16360, 16362, 16367, 16398) can be found in
http://grb.rssi.ru/GRB140606B/grb140606B_lc.png
Based on the lc above one can suggest that a host galaxy of GRB 140606B
may influence on the photometry of the afterglow.
- GCN Circular #16412
V. Mangano (PSU)
on behalf of the Swift-XRT team:
Swift XRT observed the field of GRB 140606B twice after
its return to normal operations for a total of 9 ks exposure.
We confirm that the light curve of the X-ray source given
in Mangano et al. (GCN Circ. 16366 and 16373) shows a
power-law decay with slope 1.0 (+0.7,-0.6).
This circular is an official product of the Swift-XRT team.
- GCN Circular #16431
A.S. Moskvitin, V.N. Komarova, V.V. Sokolov, T.N. Sokolova (SAO RAS),
A.F. Valeev (SAO RAS, Kazan Federal Uni.) report on behalf of a larger
GRB follow-up collaboration:
We observed the GRB 140606B / iPTF 14bfu field (Singer et al.,
GCNC 16360) with the 1-m Zeiss-1000 telescope of SAO RAS on June 19/20,
21:26:29 - 00:22:32 UT (13.8 days since the Fermi/GBM trigger).
25 images in Rc band with the total exposure 7500 seconds were obtained.
Near the GRB OT location we clearly detect an object with the brightness
R = 22.1 +/- 0.2, measured against nearby USNO-B1 stars.
This magnitude agrees with the value measured by Volnova et al.
on June 8 (GCNC 16403). Such stability supports an idea that it may be
the host galaxy of GRB 140606B (Perley et al., GCNC 16365).
- GCN Circular #16454
D. A. Perley (Caltech), M. L. Graham, A. V. Filippenko (UC Berkeley),
and S. B. Cenko (GSFC) report:
We acquired a single 1200-second spectrum of iPTF14bfu (Singer et al.,
GCN 16360; Perley et al., GCN 16365), the optical transient associated
with GRB 140606B (Burns et al., GCN 16363), using the Low Resolution
Imaging Spectrometer (LRIS) on the Keck I 10-meter telescope. The
observation was conducted starting at 13:00 UT on 2014-06-24, 18.4 days
after the GBM trigger, and covers a wavelength range from 320-1028
nanometers.
The spectrum shows several broad emission features and a significant
decrease in flux toward both the blue and red ends. A comparison with
SN 1998bw* using superfit (Howell et al. 2005, ApJ 634, 1190) shows a
good match between the observed features and the spectrum of SN 1998bw
near maximum light, indicating that the transient has evolved into a
Type Ic-BL supernova.
* http://www.astro.caltech.edu/~dperley/grb/140606b/140606b_98bw.png
- 1505.03522 from 15 May 15
Z. Cano et al.: GRB 140606B / iPTF14bfu: Detection of shock-breakout emission from a cosmological gamma-ray burst?
We present optical and near-infrared photometry of GRB 140606B ($z=0.384$), and optical photometry and spectroscopy of its associated supernova
(SN). The bolometric properties of the SN are: a nickel mass of M$_{\rm Ni}$=0.4$\pm$0.2 M$_{\odot}$, an ejecta mass of M$_{\rm ej}$=5$\pm$2
M$_{\odot}$, and a kinetic energy of E$_{\rm K}$=2$\pm1\times10^{52}$ erg. The uncertain value of M$_{\rm Ni}$ is primarily due to the poorly
constrained rest-frame extinction ($E(B-V)_{\rm rest}$=0.16$\pm$0.14 mag). The photospheric velocity of the SN near maximum light is $v_{\rm
ph}\approx$20,000 km/s. The photospheric velocity and bolometric properties are fully consistent with the statistical averages determined for
other GRB-SNe. However, in terms of its $\gamma$-ray emission, GRB 140606B is an outlier of the Amati relation, and occupies the same region as
low-luminosity ($ll$) and short GRBs. The $\gamma$-ray emission in $ll$GRBs is thought to arise, at least in some events, from a shock-breakout
(SBO), rather than from a jet. The measured peak photon energy is $E_{\rm p}\approx800$ keV, which is close to the value expected for
gamma-rays created by a SBO ($\approx 1$ MeV). Moreover, based on its position in the $M_{V,\rm p}$--$L_{\rm iso,\gamma}$ plane and the $E_{\rm
K}$--$\Gamma\beta$ plane, GRB 140606B has properties similar to both SBO-GRBs and jetted-GRBs. Finally, we searched for correlations between
the isotropic $\gamma$-ray emission and the bolometric properties of a sample of GRB-SNe, finding that no statistically significant correlation
is present. The average kinetic energy of the sample is <$E_{\rm K}$>=2.1$\times10^{52}$ erg. All of the GRB-SNe in our sample, with the
exception of SN 2006aj, are within this range, which has implications for the total energy budget available to power both the relativistic and
non-relativistic components in a GRB-SN event. [abridged]
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