GRB 100615A
GCN Circular 10841
Subject
GRB 100615A: Swift detection of a burst
Date
2010-06-15T02:13:23Z (15 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
V. D'Elia (ASDC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU),
J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC),
J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC),
C. B. Markwardt (CRESST/GSFC/UMD), T. Sakamoto (NASA/UMBC),
M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC), G. Stratta (ASDC),
T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the
Swift Team:
At 01:59:03 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100615A (trigger=424733). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 177.207, -19.496 which is
RA(J2000) = 11h 48m 50s
Dec(J2000) = -19d 29' 45"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows 3 strong peaks
with a duration of about 60 sec. The peak count rate
was ~7000 counts/sec (15-350 keV), at ~5 sec after the trigger.
The XRT began observing the field at 02:00:06.4 UT, 62.4 seconds after
the BAT trigger. Using promptly downlinked data we find a bright, fading,
uncatalogued X-ray source located at RA, Dec 177.20376, -19.48169 which
is equivalent to:
RA(J2000) = 11h 48m 48.90s
Dec(J2000) = -19d 28' 54.1"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 52 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (3.28e+20
cm^-2, Kalberla et al. 2005), with an excess column of 1.3
(+0.47/-0.39) x 10^22 cm^-2 (90% confidence).
The initial flux in the 2.5 s image was 6.15e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 71 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag.
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.05.
Burst Advocate for this burst is V. D'Elia (delia AT asdc.asi.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 Circular 10842
Subject
GRB 100615A: NTT/Ultracam imaging
Date
2010-06-15T04:14:30Z (15 years ago)
From
Nial Tanvir at IofA U.Cambridge <nrt@ast.cam.ac.uk>
V. Dhillon (U. Sheffield), R. Mignani (MSSL), S. Schulze (U. Iceland),
A. J. Levan (U. Warwick), N. R. Tanvir (U. Leicester), A. de Cia (U.
Iceland) report on behalf of the ULTRACAM collaboration:
We observed the field of GRB 100615A (D'Elia et al., GCN 10841) with
ULTRACAM (Dhillon et al., MNRAS, 2007, 378, 825) mounted on the 3.5-m NTT
telescope on La Silla, beginning approximately 17 mins post-burst.
Stacking the images from 02:16:27 to 02:39:29 UT did not reveal any new
source down to 24 mag (3 sigma) in the i' band.
The deep limiting magnitude at early times, coupled with bright X-ray
afterglow with moderate hydrogen column density (D'Elia et al. GCN 10841)
is suggestive of a highly extinguished burst.
GCN Circular 10843
Subject
GRB 100615A: PAIRITEL NIR Upper Limits
Date
2010-06-15T05:41:52Z (15 years ago)
From
Adam Morgan at U.C. Berkeley <qmorgan@gmail.com>
A. N. Morgan C. R. Klein, and J. S. Bloom (UC Berkeley) report:
We observed the field of GRB 100615A (D'Elia et al., GCN 10841) with
the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began
at 2010-06-15 03h21m51 UT, ~1.4 hours after the Swift Trigger, under
high airmass (~2), and continued until the source set beyond telescope
limits. In mosaics (effective exposure time of 0.56 hours) taken
simultaneously in the J, H, and Ks filters, we do not detect any
source within the XRT error circle.
The preliminary photometry yields:
post burst
t_mid (hr) exp.(hr) filt U. Limit (3 sig)
1.94 0.56 J > 18.8
1.94 0.56 H > 17.9
1.94 0.56 Ks > 16.6
All magnitudes are given in the Vega system, calibrated to 2MASS. No
correction for Galactic extinction has been made to the above reported
values.
GCN Circular 10844
Subject
GRB 100615A: GROND observations, upper limits
Date
2010-06-15T05:47:41Z (15 years ago)
From
Sylvio Klose at TLS Tautenburg <klose@tls-tautenburg.de>
A. Nicuesa, S. Klose (both TLS Tautenburg), and J. Greiner (MPE Garching),
report on behalf of the GROND team:
GROND (Greiner et al. 2008, PASP 120, 405), the 7-channel imager mounted
at the 2.2m ESO/MPI telescope on La Silla, started follow-up observations
of GRB 100615A (D'Elia et al. 2010, GCN 10841) on June 15 at 2:05 UT
(about 6 min after the trigger).
Within the 3.7 arcsec XRT error circle we do not find any afterglow
candidate. Preliminary measured upper limits based on an 8 min observing
block starting at 2:20 UT are (in the AB system, 3 sigma):
g' > 24.2,
r' > 23.9,
i' > 22.9,
z' > 22.5,
J > 21.4,
H > 20.7,
K > 20.3,
using GROND zeropoints and the 2MASS catalog. This is in agreement with
the report by Dhillon et al. about the non-detection in the i' band (GCN
10842).
GCN Circular 10847
Subject
GRB 100615A: Swift-XRT refined analysis
Date
2010-06-15T10:02:44Z (15 years ago)
From
Raffaella Margutti at U. di Milano Bicocca <raffaella.margutti@brera.inaf.it>
R. Margutti, B. Sbarufatti (INAF-OAB) and V. D'Elia (ASDC) report on
behalf of the Swift-XRT team:
We have analysed 1.1 ks of XRT data for GRB 100615A (D'Elia et al. GCN
Circ. 10841), from 68 s to 1.2 ks after the BAT trigger. The data comprise
73 s in Windowed Timing (WT) mode with the remainder in Photon Counting
(PC) mode. The light curve can be modelled with an initial power-law decay
with an index of alpha=4.17 (+0.23, -0.22), followed by a break at T+191 s
to an alpha of -0.03 (+0.23, -0.25).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.21 (+0.16, -0.15). The
best-fitting absorption column is 8.8 (+1.1, -1.0) x 10^21 cm^-2, in
excess of the Galactic value of 3.3 x 10^20 cm^-2 (Kalberla et al. 2005).
The PC mode spectrum has a photon index of 2.6 (+0.4, -0.3) and a
best-fitting absorption column of 1.18 (+0.29, -0.25) x 10^22 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced
from this spectrum is 4.9 x 10^-11 (1.9 x 10^-10) erg cm^-2 count^-1.
If the light curve continues to decay with a power-law decay index of
-0.03, the count rate at T+24 hours will be 1.4 count s^-1, corresponding
to an observed (unabsorbed) 0.3-10 keV flux of 6.8 x 10^-11 (2.6 x 10^-10)
erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00424733.
This circular is an official product of the Swift-XRT team.
GCN Circular 10848
Subject
GRB 100615A: Enhanced Swift-XRT position
Date
2010-06-15T10:21:14Z (15 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.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 1489 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 100615A, 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 = 177.20522, -19.48118 which is equivalent
to:
RA (J2000): 11h 48m 49.25s
Dec (J2000): -19d 28' 52.2"
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 Circular 10850
Subject
GRB 100615A: Swift-BAT refined analysis
Date
2010-06-15T11:59:42Z (15 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), V. D'Elia (ASDC), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), A. M. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-61 to T+242 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 100615A (trigger #424733)
(D'Elia, et al., GCN Circ. 10841). The BAT ground-calculated position is
RA, Dec = 177.208, -19.483 deg, which is
RA(J2000) = 11h 48m 49.9s
Dec(J2000) = -19d 29' 00.0"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 99%.
The mask-weighted light curve shows 3 slightly overlapping FRED peaks
with the first starting at ~T-0.2 sec and peaking at ~T+2 sec. The second
peaks at ~T+10 sec. The third peaks at ~T+30 sec and ends at ~T+~120 sec.
T90 (15-350 keV) is 39 +- 2 sec (estimated error including systematics).
The time-averaged spectrum from T-0.0 to T+47.4 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.87 +- 0.04. The fluence in the 15-150 keV band is 5.0 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+10.26 sec in the 15-150 keV band
is 5.4 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/424733/BA/
GCN Circular 10851
Subject
GRB 100615A: Fermi GBM detection
Date
2010-06-15T13:47:12Z (15 years ago)
From
Suzanne Foley at MPE <sfoley@mpe.mpg.de>
S. Foley (MPE) and M. Briggs (UAH)
report on behalf of the Fermi GBM Team:
"At 01:59:04.37 UT on 15 June 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100615A (trigger 298259946 / 100615083)
which was also detected by the SWIFT-BAT
(D'Elia et al. 2010, GCN 10841).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 64 degrees.
The GBM light curve consists of 3 main pulses
with a duration (T90) of about 37.7 +/- 0.8 s (10-1000 keV).
The time-averaged spectrum from T0+0.003 s to T0+39.553 s is
best fit by a power law function with an exponential
high energy cutoff. The power law index is -1.34 +/- 0.04 and
the cutoff energy, parameterized as Epeak, is 106.20 (+7.53/-6.07) keV
(CSTAT 989.31 for 606 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(8.64 +/- 0.17)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+9.7 s in the 8-1000 keV band
is 8.3 +/- 0.2 ph/s/cm^2.
A Band function fits the spectrum equally well (CSTAT 976.41 for 605 d.o.f.)
with Epeak = 85.73 (+7.82/-9.33) keV, alpha = -1.24 (+0.08/-0.06) and
beta = -2.27 (+0.11/-0.12).
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 10856
Subject
GRB 100615A: Swift/UVOT Upper Limits
Date
2010-06-15T19:21:44Z (15 years ago)
From
Stephen Holland at USRA/NASA/GSFC/SSC <Stephen.T.Holland@nasa.gov>
S. T. Holland (CRESST/GSFC/USRA) and
V. D'Elia (ASDC)
report on the behalf of the Swift UVOT team:
The Swift/UVOT observed the field of GRB 100615A starting 53 s
after the BAT trigger (D'Elia, et al., 2010, GCN Circ. 10841).
Settled observations started at 72 s. We do not find any new source,
relative to the DSS, USNO-B1.0, or 2MASS at the position of the XRT
afterglow (Goad, et al. 2010, GCN Circ. 10848). Preliminary 3-sigma
upper limits for detecting a source in the finding charts, and in the
co-added images, using a 2.5 arcsecond radius circular aperture, are
Filter T_start T_stop Exp(s) Mag
--------------------------------------------
white (fc) 72 222 147 >21.5
864 1014 147 >21.5
u (fc) 284 534 246 >20.7
v 613 7037 510 >20.6
b 539 6422 490 >21.1
u 284 6216 539 >21.1
uvw1 663 7436 499 >21.1
uvm2 813 7242 413 >20.7
uvw2 589 6832 471 >21.1
white 72 6627 785 >22.2
--------------------------------------------
The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight corresponding to a
reddening of E_{B-V} = 0.05 mag (Schlegel, et al., 1998, ApJS, 500,
525). All photometry is on the UVOT photometry system described in
Poole et al. (2008, MNRAS, 383, 627).
GCN Circular 10861
Subject
GRB 100615A: Gemini/NIRI Observations
Date
2010-06-16T17:04:00Z (15 years ago)
From
S. Bradley Cenko at Caltech <cenko@srl.caltech.edu>
S. B. Cenko, D. A. Perley (UC Berkeley), N. R. Tanvir (U. Leicester), A.
J. Levan (U. Warwick), J. S. Bloom, B. E. Cobb (UC Berkeley), K. Wiersema
(U. Leicester) report on behalf of a larger collaboration:
We have imaged the field of GRB100615A (D'Elia et al., GCN 10841) with the
Near InfraRed Imager on the 8-m Gemini North telescope. Observations were
obtained in the J and K filters beginning at 7:36 UT on 15 June 2010 (~
5.5 hours after the trigger).
We find no sources inside the revised XRT error circle (Goad et al., GCN
10848) to limiting magnitudes of J > 22.1, K > 20.9 (Vega, calibrated with
respect to 2MASS). Combined with additional limits from other facilities
(Dhillon et al., GCN 10842; Morgan et al., GCN 10843; Nicuesa et al., GCN
10844; Holland and D'Elia, GCN 10856), and the large excess X-ray column
derived from XRT observations (Margutti et al., GCN 10847), we conclude
that GRB100615A is likely a highly extinguished event.
GCN Circular 10915
Subject
GRB 100615A: Chandra X-ray ToO Observation
Date
2010-07-01T20:58:13Z (15 years ago)
From
Nat Butler at UC berkeley <natxbutler@gmail.com>
N. R. Butler, D. A. Perley, S. B. Cenko, J. S. Bloom (UC Berkeley), A.
J. Levan (U. Warwick), and N. R. Tanvir (U. Leicester) report on
behalf of a larger collaboration:
Beginning 2010/06/15 01:59 UT (6.1 days post burst) and for a period
of 14.8 ksec (livetime), Chandra targeted the field of the optically
dark GRB 100615A (D'Elia et al. 2010, GCN 10841; Foley et al. 2010,
GCN 10851) with ACIS-S under Director's Discretionary Time. The X-ray
afterglow is well detected (210 cts, 0.5-8 keV) at a position
consistent with that
of the Swift GRB and afterglow (GCN 10841; Goad et al. 2010, GCN
10848). We find:
RA, Dec (J2000) = 11:48:49.34, -19:28:52.0 +/- 0.6"
The counts spectrum can be modelled by an absorbed powerlaw, with
photon index Gamma = 2.0+/-0.5 (Cash/nu = 11.2/17). The unabsorbed
flux is 3.2^{+1.4}_{-0.7} x 10^{-13} erg cm^(-2) s^(-1) (0.5-8 keV).
There is 6-sigma significant evidence (Delta Cash = 32.4 for 1
additional degree of freedom) for a large N_H column 1.0^{+0.4}_{-0.3}
x 10^22 cm^(-2) (z=0) in excess of the Galactic value (3.3 x10^20
cm^(-2); Kalberla et al. 2005). This is in agreement with the XRT
analyses (Margutti et al. 2010, GCN 10847) and further indicates that
GRB 100615A
is likely a highly extinguished event (see also, Cenko et al. 2010, GCN 10861).
All uncertainties above are 90% confidence.
We thank Harvey Tananbaum and the CXO team for permitting and rapidly
conducting this observation. This message can be cited.
GCN Circular 10928
Subject
GRB 100615A: Additional Gemini/NIRI observations
Date
2010-07-02T22:58:46Z (15 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
D. A. Perley, J. S. Bloom, S. B. Cenko, and N. R. Butler (UC Berkeley)
report:
We again observed the field of GRB 100615A (D'Elia et al. 2010, GCN
10841) using NIRI on Gemini-North between 06:06 and 07:03 on 2010-06-24
UT, at moderately high airmass. We acquired 45 images of 60 seconds
each in the K' filter, a significantly deeper integration than our
previous observation (Cenko et al., GCN 10861).
A faint object is detected slightly west of the latest online
UVOT-enhanced XRT error circle, with an aperture magnitude of K' = 21.3
+/- 0.3 mag. However, the location of this object is not consistent
with the improved X-ray localization provided by the Chandra
observations (Butler et al., GCN 10915).
A very faint possible source is visible at the Chandra location, but it
is not statistically significant (1.5-sigma). The 3-sigma limit of the
image is K' > 22.2 mag; forced photometry gives K' = 23.0 +/- 0.8 mag at
this location.
An image of the field is posted to:
http://lyra.berkeley.edu/~dperley/100615a/100615a_niri.png
GCN Circular 14264
Subject
GRB 100615A: HST host detection and X-shooter redshift
Date
2013-03-06T17:46:42Z (12 years ago)
From
Thomas Kruehler at Dark Cosmology Center <tom@dark-cosmology.dk>
T. Kruehler, D. Malesani, D. Xu, J. P. U. Fynbo (DARK/NBI), A. J. Levan
(U. Warwick), N. R. Tanvir (U. Leicester), V. D'Elia (ASDC, INAF) and
D. Perley (Caltech) report on behalf of the X-shooter GTO GRB collaboration:
The field of GRB 100615A (Swift trigger 424733, D'Elia et al., GCN 10841)
was observed with the Hubble Space Telescope and WFC3
(filters F606W and F160W) under proposal ID 11840 (PI: A. J. Levan).
Observations were carried out on 2010 Dec 16 (154 days after the GRB),
for a total exposure time of 1128 s and 1208 s, respectively.
In the HST images, we detect a single, resolved object (F160W = 24.1 AB mag)
consistent with the Chandra X-ray position (Butler et al., GCN 10915),
which we consider to be the GRB host galaxy.
Its coordinates are (J2000):
RA = 11:48:49.34
Dec = -19:28:51.8
A spectrum of this source was taken on 2013 Mar 05 with the ESO VLT
equipped with the X-shooter spectrograph, covering the wavelength range
3000-20500 AA. The seeing was 0.8". In the VIS and NIR arm,
we detect several emission lines, interpreted as the doublet of
[O II](3726, 3729), [Ne III](3869), [O III](4959), [O III](5007) and Halpha
at a common redshift of z = 1.398.
At this redshift, the afterglow data imply a very high host exinction
along the GRB sight-line (A_V > 10-15, see D'Elia & Stratta 2011, A&A, 532, A48,
their Figure 4). The intrinsic soft X-ray absorption column measured
from Swift/XRT data (Margutti et al., GCN 10847) at z = 1.398 is
N_{H,X} = 1.07 (+0.13, -0.12) x 10^23 cm^-2. This is similarly at the high end
of measured column densities, even among dark bursts
(e.g., Kruehler et al., 2012, ApJ, 758, 46, their Figure 5). In
contrast, the host of GRB 100615A is rather blue (F606W - F160W \sim 1
AB mag) and does not show obvious signs of heavy dust content.
We acknowledge excellent support from the observing staff at Paranal,
in particular Giacomo Beccari and Emanuela Pompei.