GRB 140515A
GCN Circular 16338
Subject
Chandra late-time observations of GRB140515A
Date
2014-05-28T19:03:45Z (11 years ago)
From
Raffaella Margutti at Harvard <rmargutti@cfa.harvard.edu>
R. Margutti, E. Berger, R. Chornock, W. Fong, T. Laskar and A. Zauderer
(Harvard U.) report:
"We observed the location of GRB 140515A (D'Avanzo et al., GCN 16267)
at z=6.32 (Chornock et al., GCN 16269)
with the Chandra X-ray Observatory (Program 15508477, PI Margutti).
Our observations started on May 25th, 07:38:38 UT, 858.6 ks after the BAT
trigger.
No X-ray source is detected at the position of the optical and radio
afterglow
(Fong et al., GCN 16274, Laskar et al., GCN 16283),
with a 3-sigma count-rate limit of 1.5E-4 c/s (0.3-10 keV energy range,
total exposure time of 19.8 ks).
Adopting the best fitting parameters from the total PC-mode spectrum
(photon index Gamma=1.8, intrinsic neutral hydrogen column density
NHint=2.3E+22 cm-2 at z=6.32), we compute an observed flux limit of
1.5E-15 erg/s/cm2 (0.3-10 keV). The Galactic hydrogen column density
in the direction of the burst is NHgal=2.5E+20 cm-2 (Kalberla et al.,
2005).
Our observations constrain the late-time (t> 100 ks) X-ray afterglow decay
to be steeper than t^-2.6.
We thank Belinda Wilkes and the entire Chandra team for making these
observations possible."
GCN Circular 16284
Subject
GRB 140515A: Swift-BAT refined analysis
Date
2014-05-16T20:03:00Z (11 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), P. D'Avanzo (INAF-OAB), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), J. Tueller (GSFC),
T. N. Ukwatta (MSU) (i.e. the Swift-BAT team):
Using the data set from T-288 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 140515A (trigger #599037)
(D'Avanzo, et al., GCN Circ. 16267). The BAT ground-calculated position is
RA, Dec = 186.071, 15.099 deg which is
RA(J2000) = 12h 24m 17.0s
Dec(J2000) = +15d 05' 55.8"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 99%.
The mask-weighted light curve shows a double-peaked structure. The first pulse
starts at ~T-22 s and peaks at ~T-18 s. The second pulse starts at ~T-10 s, peaks
at ~T+2 s, and ends at ~T+4 s. T90 (15-350 keV) is 23.4 +- 2.1 sec (estimated
error including systematics).
The time-averaged spectrum from T-22.0 to T+3.8 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 0.98 +- 0.64,
and Epeak of 51.3 +- 14.7 keV (chi squared 54.37 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 5.9 +- 0.6 x 10^-7 erg/cm2
and the 1-sec peak flux measured from T+1.51 sec in the 15-150 keV band is
0.9 +- 0.1 ph/cm2/sec. A fit to a simple power law gives a photon index
of 1.85 +- 0.13 (chi squared 61.03 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/599037/BA/
GCN Circular 16283
Subject
GRB 140515A: VLA Detection
Date
2014-05-16T17:06:52Z (11 years ago)
From
Tanmoy Laskar at Harvard U <tanmoylaskar@gmail.com>
T. Laskar, A. Zauderer, and E. Berger (Harvard) report:
"We observed the position of GRB 140515A (D'Avanzo et al; GCN 16267) at
multiple frequencies with the VLA beginning 2014 May 16.00 UT (0.62 days
after the burst). At a mean frequency of 21.8 GHz, we detect a radio source
with a preliminary flux density of ~ 0.1 mJy at
RA = 12:24:15.5055 +/- 0.0005
Dec = +15:06:16.609 +/- 0.005
consistent with the enhanced Swft/XRT position (D'Avanzo et al.; GCN 16277)
and the optical position (Fong et al.; GCN 16274). Follow-up observations
are planned."
GCN Circular 16282
Subject
GRB 140515A : TNG near-infrared observations
Date
2014-05-16T15:51:49Z (11 years ago)
From
Andrea Melandri at INAF-OAB <andrea.melandri@brera.inaf.it>
A. Melandri, P. D'Avanzo (INAF/OAB), A. Fiorenzano and G. Mainella (INAF/TNG) report on behalf of the CIBO collaboration:.
We observed the field of GRB 140515A (D'Avanzo et al., GCN 16267) using the NICS near-Infrared camera on the 3.6m TNG Telescope (La Palma, Canary Islands).
We obtained a series of imaging observations in the J and H bands for a total exposure time of 30 and 60 minutes respectively. The GRB afterglow is clearly detected in both bands at a level of
Dt Exposure Filter Mag (err)
[hr from GRB] [min]
14.54 60 H 19.35 (0.12)
15.60 30 J 19.52 (0.18)
Magnitudes are in the Vega system, calibrated against the 2MASS catalogue. We thank the TNG staff for the support.
GCN Circular 16280
Subject
GRB 140515A: GROND observation of the afterglow
Date
2014-05-16T12:22:49Z (11 years ago)
From
Sebastian Schmidl at TLS Tautenburg <schmidl@tls-tautenburg.de>
J. Graham (MPE Garching), S. Schmidl (TLS Tautenburg), and J. Greiner
(MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 140515A (Swift trigger 599037; D'Avanzo et
al., GCN 16267) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2m MPG telescope at ESO La Silla
Observatory (Chile).
Observations started at 22:53 UT on March 15, 2014, 13.7 hrs after
the GRB trigger. They were performed at an average seeing of 0.9" and at
an average airmass of 1.4.
We detect the afterglow reported by Chornock et al. (GCN 16269).
Based on a total exposure of 50 min in g'r'i'z' and 40 min in JHK, at
a mid-time of 17.0 hrs after the burst, we measure the following
preliminary magnitudes (in AB):
g' > 24.1 mag,
r' > 24.5 mag,
i' > 24.2 mag,
z' = 22.1 +/- 0.1 mag,
J = 20.9 +/- 0.2 mag,
H = 20.9 +/- 0.2 mag, and
K > 19.1 mag.
Based on these data, the photometric redshift is z= 6.5 +/-0.2, which is
consistent with the spectroscopic redshift reported by Chornock et al.
(GCN 16269).
Given magnitudes are calibrated against SDSS (g'r'i'z') as well as 2MASS
(JHK) field stars and are not corrected for the expected Galactic
foreground
extinction corresponding to a reddening of E_(B-V) = 0.02 mag in the
direction of the burst (Schlegel et al. 1998).
GCN Circular 16279
Subject
GRB 140515A: Spectroscopy from the 10.4m GTC
Date
2014-05-16T02:49:04Z (11 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), J. Gorosabel (IAA-CSIC,
UPV-EHU), C.C. Thoene (IAA-CSIC), A. Cabrera-Lavers, D. Reverte and C.
Alvarez (IAC-ULL) report on behalf of a larger collaboration:
We have obtained spectroscopic observations of the afterglow of GRB 140415A
(D'Avanzo et al., GCN 16267; Chornock et al. GCN 16269; Fong et al. GCN
16274; de Ugarte Postigo et al. GCN 16278) using the 10.4m GTC telescope
(+OSIRIS). Our observation started at 22:37 UT (13.41 hr after the burst),
with a seeing of 0.6", and consisted of 3x1800s exposures using grism
R2500I, which covers the range between 7330 and 10000 A at a resolution of
~2500.
In a preliminary reduction we detect a strong continuum above 8900 A, with
no significant absorption features. The sharp decay below 8900 A is
consistent with Ly-alpha absorption at the redshift of 6.32 suggested by
Chornock et al. (GCN 16269). The transmission of the Ly-forest is low, but
some emission is detected down to the blue limit of our spectrum.
GCN Circular 16278
Subject
GRB 140515A: Optical observations from the 2.5 m NOT
Date
2014-05-16T00:30:12Z (11 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), J. Gorosabel
(IAA-CSIC, UPV-EHU), D. Xu (DARK/NBI), J.P.U. Fynbo
(DARK/NBI), P. Jakobsson (U. Iceland), D. Malesani
(DARK/NBI), N.R. Tanvir (U. Leicester), E. Gafton
(OKC, Stockholm Univ.) and T. Libbrecht (Stockholm Univ.)
report on behalf of a larger collaboration:
We have observed the afterglow of GRB 140515A (D'Avanzo et al.,
GCN 16267) with the 2.5m NOT telescope. Observations consisted
of 5x300s imaging in the z-band and have an average epoch of
12.10 hr after the burst. The images reveal the optical afterglow
detected by Chornock et al. (GCN 16269) and Fong et al. (GCN
16274) at a magnitude of z(AB) = 22.15+/-0.15, as compared with
SDSS stars. This indicates a decay with a slope of alpha ~ -0.9
(where F_nu~t^alpha) as compared with the photometry of Fong
et al. (GCN 16274). Further observations are ongoing.
GCN Circular 16277
Subject
GRB 140515A: Swift-XRT refined Analysis
Date
2014-05-15T23:58:11Z (11 years ago)
From
Paolo D'Avanzo at INAF-OAB <paolo.davanzo@brera.inaf.it>
P. D'Avanzo, M. G. Bernardini (INAF-OAB), P. A. Evans (U. Leicester)
report on behalf of the Swift-XRT team:
We have analysed 7.1 ks of XRT data for GRB 140515A (D'Avanzo et al.
GCN Circ. 16267), from 60 s to 13.6 ks after the BAT trigger. The
data comprise 9 s in Windowed Timing (WT) mode (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. 16270).
The light curve can be modelled with a power-law decay with an initial
decay index of alpha=2.5 (+0.5, -0.3). Then at T0+1100 s the light
curve rises, reaching a count rate ~ 0.3 ct/sec. The remaining two
orbits show irregular rate variations likely due to an underlying
flaring activity, with a count rate ~ 0.3 ct/sec and ~ 0.1 ct/sec
respectively.
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.75 (+0.12, -0.11). The
best-fitting absorption column is 1.7 (+3.2, -1.7) x 10^22 cm^-2, at a
redshift of 6.32 (Chornock et al., GCN Circ. 16269), in addition to the
Galactic value of 2.5 x 10^20 cm^-2 (Willingale et al. 2013). The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.7 x 10^-11 (3.9 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Galactic foreground: 2.5 x 10^20 cm^-2
Intrinsic column: 1.7 (+3.2, -1.7) x 10^22 cm^-2 at z=6.32
Photon index: 1.75 (+0.12, -0.11)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00599037.
This circular is an official product of the Swift-XRT team.
GCN Circular 16275
Subject
GRB 140515A: KAIT Optical Upper Limit
Date
2014-05-15T19:34:45Z (11 years ago)
From
Weikang Zheng at UC Berkeley <zwk@astro.berkeley.edu>
WeiKang Zheng, Alexei V. Filippenko, Adam Morgan (UC Berkeley), and
S. B. Cenko (NASA/Goddard Space Flight Center) 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 140515A (D'Avanzo et al.,
GCN 16267) starting at 09:14:22 UT, 106 s after the burst.
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. We do not detect the optical afterglow (Chornock
et al., GCN 16269; Fong et al., GCN 16274) in our
images within the enhanced XRT error circle (Goad et al., GCN 16270).
The typical limiting magnitude of our single clear image is about
17.8, and about 17.1,16.9 mag for the V and I bands respectively.
[GCN OPS NOTE(15may14): Per author's request, the Sahu/16272 reference
was removed as it refers to a different GRB.]
GCN Circular 16274
Subject
GRB 140515A: Gemini-North imaging
Date
2014-05-15T19:26:23Z (11 years ago)
From
Wen-fai Fong at CFA <wfong@cfa.harvard.edu>
W. Fong (Harvard), R. Chornock (Harvard), D. Fox (PSU), and E. Berger
(Harvard) report:
"We observed the location of the long-duration GRB 140515A (D'Avanzo et
al., GCN 16267) with the Gemini Multi-Object Spectrograph (GMOS) mounted on
the Gemini-North 8-meter telescope at a mid-time of 2014 May 15.458 UT
(1.78 hr after the BAT trigger). We obtained 480 sec in each of the i- and
z-bands in 0.45" seeing. We detect the optical afterglow (Chornock et al.,
GCN 16269), within the enhanced XRT position (Goad et al., GCN 16270),
located at
RA(J2000) = 12:24:15.51
Dec(J2000) = +15:06:16.6
with a positional uncertainty of 0.1" in each coordinate. The optical
afterglow has a brightness of z = 20.27 +/- 0.11 AB mag, and is at least 3
mag fainter in our i-band observations. Both the astrometry and photometry
are calibrated to SDSS.
We thank the Gemini staff for their assistance with these observations."
GCN Circular 16273
Subject
GRB 140515A: Swift/UVOT Upper Limits
Date
2014-05-15T18:09:41Z (11 years ago)
From
Samantha Oates at MSSL <sro@mssl.ucl.ac.uk>
S. R. Oates (IAA-CSIC,UCL-MSSL) and P. D'Avanzo (INAF-OAB)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 140515A
79 s after the BAT trigger (D'Avanzo et al., GCN Circ. 16267).
No optical afterglow consistent with the XRT position
(Goad et al. GCN Circ. 16270) is detected in the initial UVOT exposures.
The lack of detection in all UVOT filters is consistent with a redshift of
6.32 (Chornock et al., GCN Circ. 16269).
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
white_FC 79 229 147 >20.7
u_FC 293 542 246 >20.0
white 79 7407 638 >21.5
v 628 7818 471 >19.7
b 548 7202 456 >20.6
u 293 13671 1398 >20.9
w1 1618 12925 1140 >20.9
m2 6387 12019 1082 >20.6
w2 5977 7612 393 >20.5
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 16271
Subject
GRB 140515A: MITSuME Akeno upper limits
Date
2014-05-15T14:19:22Z (11 years ago)
From
Taketoshi Yoshii at Tokyo Tech <yoshii.t.ac@m.titech.ac.jp>
H. Ohuchi, T. Yoshii, Y. Saito, Y. Tachibana,
S. Kurita, Y. Ono, T. Fujiwara, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We observed the field of GRB 140515A (P.D'Avanzo et al., GCN Circular #16267) with the
optical three color (g, Rc, and Ic) CCD cameras attached to the MITSuME 50 cm
telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 2014-05-15 10:32:10 UT ( 1.3h after the burst).
We did not find any new point source within the enhanced XRT circle
in all the three bands.The measured magnitudes were listed below.
T0+[sec] MID-UT T-EXP[sec] g' Rc Ic
---------------------------------------------------------------------------------------------------------
9301 11:47:37 9180 > 20.8 >20.5 >19.4
---------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
GCN Circular 16270
Subject
GRB 140515A: Enhanced Swift-XRT position
Date
2014-05-15T14:10:01Z (11 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 2066 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 140515A, 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 = 186.06452, +15.10491 which is equivalent
to:
RA (J2000): 12h 24m 15.48s
Dec (J2000): +15d 06' 17.7"
with an uncertainty of 1.8 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 Circular 16269
Subject
GRB 140515A: Gemini-N redshift
Date
2014-05-15T13:55:55Z (11 years ago)
From
Ryan Chornock at Harvard <rchornock@cfa.harvard.edu>
R. Chornock (Harvard), D. B. Fox (Penn State), and E. Berger (Harvard) report:
We observed the field of GRB 140515A (D'Avanzo et al., GCN 16267) using GMOS on
the Gemini-N 8-m telescope, starting at 10:48 UT on 15 May. A faint source was
present in the i band acquisition image at a position consistent with the X-ray
afterglow. We obtained 2x900s of spectroscopy of this likely afterglow,
covering the wavelength range 5900-10150 Angstroms at a resolution of R~1200.
The afterglow has a strong continuum at long wavelengths that sharply drops to
near zero at wavelengths shortward of lambda~8900 Angs, consistent with the
onset of Lyman-alpha absorption at z=6.32. Isolated wavelength intervals of IGM
transmission exist between 7500 and 8000 Angs (corresponding to z~5.2-5.6
relative to Ly-alpha). Further analysis is ongoing.
We acknowledge excellent support from Gemini observer Lucas Fuhrman.
GCN Circular 16267
Subject
GRB 140515A: Swift detection of a burst
Date
2014-05-15T09:30:47Z (11 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
P. D'Avanzo (INAF-OAB), M. G. Bernardini (INAF-OAB), V. D'Elia (ASDC),
P. A. Evans (U Leicester), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL) and
B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team:
At 09:12:36 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 140515A (trigger=599037). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 186.036, +15.077 which is
RA(J2000) = 12h 24m 09s
Dec(J2000) = +15d 04' 38"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a double-peaked
structure with a duration of about 30 sec. The peak count rate
was ~1200 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 09:13:52.4 UT, 75.8 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 186.0639,
15.1045 which is equivalent to:
RA(J2000) = 12h 24m 15.35s
Dec(J2000) = +15d 06' 16.4"
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This
location is 138 arcseconds from the BAT onboard position, within the
BAT error circle. This position may be improved as more data are
received; the latest position is available at
http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 2.54
x 10^20 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 79 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 none of
the XRT error circle. The 8'x8' region for the list of sources generated
on-board covers 100% of the XRT error circle. The list of sources is typically
complete to about 18 mag. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.02.
Burst Advocate for this burst is P. D'Avanzo (paolo.davanzo AT brera.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.)