GRB 070411
GCN Circular 6267
Subject
GRB 070411: Swift detection of a burst with optical afterglow
Date
2007-04-11T20:43:42Z (18 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
A. Moretti (INAF-OAB), S. D. Barthelmy (GSFC), P. J. Brown (PSU),
D. N. Burrows (PSU), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC),
G. Cusumano (INAF-IASFPA), N. Gehrels (NASA/GSFC),
S. T. Holland (CRESST/GSFC/USRA), J. A. Kennea (PSU),
H. A. Krimm (GSFC/USRA), V. Mangano (INAF-IASFPA),
F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester),
C. Pagani (PSU), D. M. Palmer (LANL),
P. Romano (Univ. Bicocca & INAF-OAB), T. Sakamoto (NASA/ORAU),
B. Sbarufatti (INAF-IASFPA), M. Stamatikos (NASA/ORAU),
R. L. C. Starling (U Leicester), G. Tagliaferri (INAF-OAB),
D. E. Vanden Berk (PSU), S. D. Vergani (DIAS-DCU) and
H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:
At 20:12:33 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 070411 (trigger=275087). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 107.338, +1.083 which is
RA(J2000) = 07h 09m 21s
Dec(J2000) = +01d 04' 57"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows an initial weak peak
starting at T-1 sec and fading by T+5 sec and then a stronger second peak
from T+50 to T+90 sec with an amplitude of ~1000 cnts/sec
in the 15-350 keV band.
The XRT began observing the field at 20:14:09 UT, 96 seconds after the
BAT trigger. XRT found an uncatalogued X-ray source
located at RA, Dec 107.3327, +1.0632 which is
RA(J2000) = 07h 09m 19.8s
Dec(J2000) = 01d 03' 47.5"
with an uncertainty of 4.7 arcseconds (radius, 90% containment).
This location is 74 arcseconds from the BAT on-board position,
within the BAT error circle. The initial flux in the 2.5s image
was 5.1e-09 erg/cm2/s (0.2-10 keV).
UVOT took a finding chart exposure of nominal 100 seconds with the
White (160-650 nm) filter starting 244 seconds after the BAT trigger.
An afterglow candidate has been found in the initial data products.
The 2.7'x2.7' region for the list of sources generated on-board
covers 100% of the XRT error circle. A source is detected at
RA = 07:09:19.93
Dec = +01:03:52.6
with an estimated uncertainty of +/-0.5 arcsec. The
estimated magnitude in the White filter is 18.7. No correction has
been made for the large, but uncertain extinction corresponding
to a reddening of 0.3 mag.
GCN Circular 6268
Subject
GRB 070411: Tautenburg RRM Afterglow Confirmation
Date
2007-04-11T21:07:32Z (18 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann, S. Schulze, U. Laux, S. Klose (TLS Tautenburg) and J.
Greiner (MPE) report:
The location of the Swift GRB 070411 (Moretti et al., GCN
6267) was observed in good conditions but at high airmass with
the Tautenburg 1.34m Schmidt Telescope in Rapid Response
Mode (Klose et al., GCN 3609) upon receipt of the BAT
position.
The first image (Rc Band, 180 sec integration) was started at
20:18:15 UT, 5 minutes and 42 seconds after the burst trigger.
We confirm a bright stationary source in the flight-localized
XRT error circle, in accordance with the UVOT position (Moretti
et al., GCN 6267). The afterglow was discovered independently
of the UVOT observation.
Further analysis and observations are in progress.
This message may be cited.
[GCN OPS NOTE(12apr07): Per author's request, UL was added to the
author list.]
GCN Circular 6269
Subject
GRB 070411: ROTSE-III Detection of Optical Counterpart
Date
2007-04-11T21:21:03Z (18 years ago)
From
Eli Rykoff at U of Michigan/ROTSE <erykoff@umich.edu>
E.S. Rykoff (U Mich), W. Rujopakarn (Steward), R. Quimby (U Texas),
B. E. Schaefer (Louisiana State), H. Swan (U Mich), S.A. Yost (U
Mich), report on behalf of the ROTSE collaboration:
ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia,
responded to GRB 070411 (Swift trigger 275087, GCN 6267, Moretti, et
al.). The first image was at 20:15:25.1 UT, 172 s after the burst;
the response was delayed due to a GCN connection problem. We took 10
5s exposures followed by 50+ 20s exposures. The unfiltered images are
calibrated relative to USNO B1.0, and no correction has been made for
the large Galactic extinction in the direction of the burst.
We confirm the afterglow candidate reported by Moretti, et al. (GCN
6267) and Kann, et al. (GCN 6268). The afterglow was marginally
detected in the first few coadded images (stacking 10 images at a
time). We see the afterglow brighten significantly during our
observations, to a peak of 17.7+/-0.1 mag, around 900s after the
burst; due to the faint afterglow, our time resolution is very coarse.
start UT exptime tstart-tburst (s) mag
----------------------------------------------------------
20:15:25.2 50.0 172 18.2+/-0.4
20:21:53.7 200.0 560 18.5+/-0.4
20:26:50.0 200.0 856 17.7+/-0.1
20:31:45.8 200.0 1152 18.6+/-0.4
A jpeg image is available at
http://www.rotse.net/images/gsb275087_3c031-040_key.jpg
Continuing observations are in progress.
GCN Circular 6270
Subject
GRB 070411: Optical observations at Crni Vrh
Date
2007-04-11T21:27:22Z (18 years ago)
From
Herman Mikuz at OCV <herman.mikuz@fmf.uni-lj.si>
H. Mikuz, J. Skvarc and B. Dintinjana on behalf of PIKA observing program
at Crni Vrh Observatory:
We observed the afterglow of GRB 070411 (Moretti et al., GCN 6267) with 60
cm Cichocki robotic telescope at Crni Vrh Observatory, Slovenia. The 90
second exposure with R filter started at 20:14:01UT, 48 seconds after
reception of the alert. We confirm optical afterglow found by UVOT. The
object measured coordinates are ra=07:09:19.95, dec=+01:03:52.8,
approximate brightness is R=17.9. The object faded on subsequent images.
Further photometric analysis is in progress.
GCN Circular 6271
Subject
GRB 070411 : Liverpool Telescope Observations
Date
2007-04-11T23:22:35Z (18 years ago)
From
Andrea Melandri at Liverpool John Moores U <axm@astro.livjm.ac.uk>
A. Gomboc (Univ. of Ljubljana, Slovenia), A. Melandri, C.G. Mundell,
I. A. Steele, D. Carter, M. Burgdorf, C. Guidorzi, A. Monfardini,
S. Kobayashi, D. Bersier (Liverpool JMU) and N. Tanvir (Leicester
University) report:
The 2-m Liverpool Telescope started observing the field of GRB070411
(Moretti et al. GCN 6267) in r'i'g' filters at 1 hr 20 min after the
trigger time.
We detect the optical candidate identified by Moretti et al. (GCN 6267),
Kann et al (GCN 6268), Rykoff et al. (GCN 6269) and Mikuz et al. (GCN
6270)
in all filters.
We estimate the magnitude of the source to be R = 19.7 +/- 0.15 at
t = 1.36 hr and I = 19.0 +/- 0.3 at t = 1.43 hr after the trigger time.
Magnitudes were calibrated vs the USNOB1 catalogue.
Further analysis and observations are ongoing.
GCN Circular 6272
Subject
GRB 070411: IAC80 optical observations
Date
2007-04-12T00:08:20Z (18 years ago)
From
Martin Jelinek at Inst.Astrophys.Andalucia,Granada <mates@iaa.es>
M. Jelinek (IAA-CSIC, Granada). J. A. Caballero (MPIA
Heidelberg), A. de la Nuez (IAC La Laguna) and A. J.
Castro-Tirado (IAA-CSIC),
report:
"We have observed the field of GRB070411 (Moretti
et al. GCNC 6267) and its associated optical
afterglow (Moretti et al., Kann et al. GCNC 6268,
Rykoff et al. GCNC 6269, Mikuz et al. GCNC 6270,
Gomboc et al. GCNC 6271) with the IAC80 telescope
at Observatorio del Teide in BVR filters, starting
at 21:45 UT, i.e. 1.5 h after the trigger.
The OA has faded to R=20.1+-0.1 (USNO-B1.0) at the
epoch of our first observation."
GCN Circular 6274
Subject
GRB 070411, Swift-BAT refined analysis
Date
2007-04-12T02:25:31Z (18 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
C. Markwardt (GSFC/UMD), L. Barbier (GSFC), S. D. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), A. Moretti (INAF-OAB), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC)
on behalf of the Swift-BAT team:
Using the data set from T-119 to T+303 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 070411 (trigger #275087)
(Moretti, et al., GCN Circ. 6267). The BAT ground-calculated position is
RA, Dec = 107.345, 1.051 deg which is
RA(J2000) = 7h 9m 22.9s
Dec(J2000) = 1d 3' 4.9"
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 74%.
The mask-weighted lightcurve shows two main peaks. The first starts at
T-60 sec, peaks at T+5 sec with a minimum at T+45 sec. The second peaks
at T+65 sec and ends at T+135 sec. T90 (15-350 keV) is 101 +- 5 sec
(estimated error including systematics).
The time-averaged spectrum from T-20 to T+109.5 is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.71 +- 0.10. The fluence in the 15-150 keV band is 2.5 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+70.22 sec in the 15-150 keV band
is 1.0 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
GCN Circular 6277
Subject
GRB 070411: Magellan/IMACS photometry
Date
2007-04-12T03:16:51Z (18 years ago)
From
Edo Berger at Carnegie Obs <eberger@ociw.edu>
E. Berger (Carnegie) and H. Yee (Toronto) report:
"We obtained a 180 sec image in I-band with the IMACS instrument on the
Magellan/Baade telescope on 2007 Apr 11.99 UT (3.55 hr after the burst).
We detect the afterglow with I=20.3 mag relative to the USNO-B star
located at RA=07:09:17.9453, DEC=+01:04:09.210 with I=17.8 mag."
GCN Circular 6278
Subject
GRB 070411: Magellan/Clay photometry
Date
2007-04-12T04:05:59Z (18 years ago)
From
Edo Berger at Carnegie Obs <eberger@ociw.edu>
E. Berger (Carnegie), M. Modjaz, A. Garg, R. Kirshner, P. Challis
(Harvard), and A. Rest (NOAO) report:
"We obtained a 60 sec image in r-band with the LDSS3 instrument on the
Magellan/Clay telescope on 2007 Apr 12.03 UT (4.57 hr after the burst). We
detect the afterglow with r=20.8 mag relative to the USNO-B star located
at RA=07:09:17.9453, DEC=+01:04:09.210 with R=17.6 mag."
GCN Circular 6283
Subject
GRB 070411: OA redshift
Date
2007-04-12T09:22:01Z (18 years ago)
From
Pall Jakobsson at U Hertfordshire <P.Jakobsson@herts.ac.uk>
Pall Jakobsson (U. Hertfordshire), Daniele Malesani,
Christina C. Thoene, Johan P. U. Fynbo, Jens Hjorth
(DARK, NBI), Andreas O. Jaunsen (U. Oslo),
Michael I. Andersen (Potsdam) and Paul M. Vreeswijk
(ESO), report on behalf of a larger collaboration:
Using FORS2 on the Very Large Telescope, we have obtained
2*10 min spectra (grism 1400V) of the optical afterglow
of GRB 070411 (Moretti et al., GCN 6267) on April 12.05.
The combined spectrum displays several absorption features,
including Ly-alpha, C II, C II*, Si II, Si IV and Fe II,
corresponding to a redshift of z = 2.954 (based on a
preliminary wavelength calibration).
We thank the Paranal staff for excellent support,
especially Leo Vanzi and Thomas Rivinius.
GCN Circular 6286
Subject
GRB 070411: Swift-XRT refined analysis
Date
2007-04-12T10:58:22Z (18 years ago)
From
Alberto Moretti at Obs Brera Merate <alberto.moretti@brera.inaf.it>
A. Moretti (INAF-OAB), P. Romano (Univ. Bicocca & INAF-OAB),
C. Guidorzi (Univ. Bicocca & INAF-OAB) report on behalf of
the Swift-XRT team:
We have analysed the first 4 orbits of Swift-XRT data obtained for GRB
070411 (trigger=275087, GCN 6267). At the moment the 1st orbit dataset
is not complete. The currently available data consist of 4.2 ks in
Photon Counting (PC) starting 500 seconds after the BAT trigger. Using
PC data we obtain a refined position of:
RA(J2000) = 07h 09m 19.96s
Dec(J2000)= +01d 03' 51.8"
with an estimated uncertainty radius of 3.7 arcsec (90% containment).
This location is 1.2 arcseconds from the UVOT position (GCN 6267).
The afterglow shows a decay which can be fitted well by a
single power law (alpha=0.87+/-0.08) up to the end of the
fourth orbit (t=17.0 ks). At this point the observed count rate was
6.8E-2 counts per second, corresponding to an unabsorbed flux of
5.2E-12 erg/cm2/sec. At 24 hours from the burst the expected
afterglow unabsorbed flux is 1.1E-12 erg/cm2/sec (1.4E-2 counts
per second).
The spectrum formed from the PC data can be modelled with a
an absobed power-law of photon index Gamma = 2.1 +/- 0.2 and
and an absorption column density consistent with the Galactic
value (2.9+/-0.9 E21 cm^-2; Dickey & Lockman, 1990).
All errors are quoted at 90% confidence level.
This circular is an official product of the Swift-XRT team.
GCN Circular 6288
Subject
GRB 070411: Optical photometry at Crni Vrh
Date
2007-04-12T13:15:01Z (18 years ago)
From
Herman Mikuz at OCV <herman.mikuz@fmf.uni-lj.si>
H. Mikuz, J. Skvarc and B. Dintinjana on behalf of PIKA observing program at
Crni Vrh Observatory:
Following the GCN 6270, we performed the analysis of images, obtained with
R and B photometric filters. Photometry results are given in table below.
Time refers to exposure start.
Time (UT) h m s Exposure (s) Mag. Err. Filter
2007 Apr 11 20:14:00.8 90 18.7 0.2 R
2007 Apr 11 20:19:31.8 90 18.2 0.2 R
2007 Apr 11 20:25:02.7 90 18.4 0.2 R
2007 Apr 11 20:30:33.6 90 18.8 0.3 R
2007 Apr 11 20:36:04.3 90 19.7 0.7 R
2007 Apr 11 20:41:35.2 90 not detected R
2007 Apr 11 20:16:00.9 180 19.9 0.7 B
2007 Apr 11 20:21:32.0 180 19.1 0.3 B
2007 Apr 11 20:27:03.0 180 19.3 0.3 B
2007 Apr 11 20:32:33.9 180 19.9 0.6 B
2007 Apr 11 20:38:04.6 180 not detected B
2007 Apr 11 20:43:35.3 180 not detected B
The magnitudes are derived using comparison stars from the USNO-B1
catalogue. The 3-sigma limiting magnitude in R filter is around magnitude
19.8, and about 20.0 in B filter. Fits images are available at
http://www.observatorij.org/Data/GRB/2007-04-11/GRB070411.tgz
GCN Circular 6291
Subject
GRB 070411: Swift/UVOT observations
Date
2007-04-12T14:00:03Z (18 years ago)
From
Samantha Oates at MSSL <sro@mssl.ucl.ac.uk>
S.R.Oates (UCL-MSSL) and A. Moretti (INAF-OAB) report on behalf of the
Swift/UVOT team:
The Swift/UVOT began observing the field of GRB 070411 on 2007-04-11 at
20:16:37 UT, 243s after the BAT trigger (Moretti et al., GCN 6267). A weak
afterglow is detected in the WHITE, V and B filters at a refined position:
RA(J2000) = 07:09:19.903
Dec(J2000) = +01:03:52.95
The magnitudes and 3 sigma upper limits are provided in the table below.
The numbers in square brackets represent the significance of the detections.
Filter Start(s) End(s) Exposure Magnitude
-----------------------------------------------------------------
WHITE 242.9 342.7 98.2 18.76 +/- 0.13 [8.3]
WHITE 4418.0 4617.8 196.6 20.56 (3sigma UL)
V 349.2 368.9 19.5 17.40 +/- 0.33 [3.3]
V 4827.9 4911.8 82.6 18.81 (3sigma UL)
B 445.9 455.7 9.6 19.02 +/- 0.65 [1.8]
B 4213.5 4413.2 196.6 20.56 +/- 0.51 [2.1]
U 421.5 4208.2 216.1 19.87 (3sigma UL)
UVW1 397.5 16931.8 833.9 20.89 (3sigma UL)
UVM2 373.1 16297.4 1326.0 21.38 (3sigma UL)
UVW2 474.9 4823.2 216.1 20.37 (3sigma UL)
------------------------------------------------------------------
These magnitudes are not corrected for the Galactic reddening of E(B-V)=0.285.
The value of the Galactic reddening is uncertain as the burst lies at a
Galactic latitude of +5 degrees.
GCN Circular 6295
Subject
GRB 070411: TLS data shows plateau, flares
Date
2007-04-13T00:48:22Z (18 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann, U. Laux, S. Klose, H. Meusinger, S. Schulze (TLS
Tautenburg) and J. Greiner (MPE, Garching) report:
The afterglow of the Swift GRB 070411 (Moretti et al., GCN
6267) was observed with the Tautenburg 1.34m Schmidt
telescope in RRM mode starting 342 seconds after the trigger
(Kann et al., GCN 6268).
A total of 18 observations were obtained before the afterglow
become unobservable. We performed aperature photometry
vs. two unsaturated and isolated USNO B1.0 stars (R1
magnitudes):
RA = 07:09:17.16, Dec. = +01:04:35.9, assuming R = 15.55
RA = 07:09:28.54, Dec. = +01:03:57.1, assuming R = 16.25
We derive the following magnitudes (mean exposure times
after the burst have been derived logarithmically):
dt Start Exposure R mag dR
(days) (SOD) (seconds)
0.0049994 73095 180 18.03 0.05
0.0076498 73324 180 18.12 0.03
0.0103234 73555 180 18.18 0.03
0.0129739 73784 180 18.17 0.05
0.0156244 74013 180 18.43 0.07
0.0182864 74243 180 18.79 0.05
0.0209485 74473 180 18.83 0.07
0.0235989 74702 180 18.95 0.08
0.0262494 74931 180 19.23 0.07
0.0288999 75160 180 19.38 0.09
0.0315503 75389 180 19.75 0.12
0.0342008 75618 180 20.00 0.16
0.0368512 75847 180 19.83 0.12
0.0395017 76076 180 19.88 0.15
0.0421522 76305 180 20.13 0.19
0.0472965 76540 600 20.64 0.23
0.0548081 77189 600 19.91 0.14
0.0623197 77838 600 19.96 0.15
Adding further R and CR data (Rykoff et al., GCN 6269,
Gomboc et al., GCN 6271, Jelinek, Nuez, & Castro-Tirado,
GCN 6272, Berger et al., GCN 6278, Mikuz, Skvarc, &
Dintinjana, GCN 6288), we find:
The afterglow may be rising early on, looking at the earliest
detections from Crni Vrh, ROTSE and Tautenburg.
The afterglow then goes over into a plateau phase (decay
alpha= 0.14 +/- 0.1). In our data, we do not see the strong
rebrightening detected by ROTSE (Rykoff et al., GCN 6269).
At 0.014 +/- 0.001 days, the afterglow breaks and begins a
decay with alpha = 1.54 +\- 0.16 up to about 0.03 days, where a
possible flare occurs.
At about 0.05 days, the afterglow seems to rebrighten strongly,
our data here are in full accordance with those of the Liverpool
telescope (Gomboc et al., GCN 6271) and the IAC80 (Jelinek,
Nuez, & Castro-Tirado, GCN 6272).
Further photometric follow-up of this GRB is warranted.
This message may be cited.
GCN Circular 6319
Subject
GRB 070411: Deep VLT detection
Date
2007-04-19T19:05:33Z (18 years ago)
From
Patrizia Ferrero at TLS Tautenburg <ferrero@tls-tautenburg.de>
P. Ferrero, S. Klose, D. A. Kann and S. Schulze (TLS Tautenburg)
report on behalf of a larger collaboration
The afterglow of GRB 070411 (Moretti et al., GCN 6267; Kann et al., GCN 6268)
was observed with VIMOS at VLT/UT3 in imaging mode. A 150 second observation
was obtained in the Rc filter at 3.1498 days after the GRB.
The afterglow is clearly detected. We measure Rc = 24.22 +/- 0.13 versus nearby comparison stars.
We thank D. Malesani for supplying the magnitudes of the comparison stars and
the ESO staff for their excellent support.
GCN Circular 6335
Subject
GRB 070411: BART early limit
Date
2007-04-20T15:30:56Z (18 years ago)
From
Martin Jelinek at Inst.Astrophys.Andalucia,Granada <mates@iaa.es>
Jan Strobl (ASU Ondrejov), Martin Jelinek (IAA
CSIC Granada), Martin Nekola, Filip Munz, Rene
Hudec (ASU) and Petr Kubanek (IAA, U. Valencia)
report
The robotic telescope BART in Ondrejov followed
automatically the GRB 070411 (Moretti et al. GCN
6267), with the first exposure starting 55.7s af-
ter the GRB trigger (15.9s after receiving the
message).
The beginning of the (unfiltered) optical observa-
tion is simultaneous to the second gamma-ray peak
of this ~100s long GRB (Markwardt et al. GCN6274).
The optical transient (Moretti et al. GCN 6267,
Kann et al. GCN6268) was not detected, giving the
following limits:
start end limit note
-----------------------------
55.7s 85.7s R>15.4 30s, simultaneous to gamma
55.7s 167.9s R>16.0 3x30s
This message may be cited
GCN Circular 6343
Subject
GRB 070411: break in the optical light curve
Date
2007-04-23T15:09:04Z (18 years ago)
From
Daniele Malesani at Niels Bohr Inst,Dark Cosmology Center <malesani@astro.ku.dk>
D. Malesani (DARK/NBI), E. Rol (Univ. Leicester), L. A. Antonelli
(INAF/OAR), J.P.U. Fynbo (DARK/NBI), P.A. Curran (UVA), K. Wiersema (UVA),
A.J. Levan (Univ. Warwick), N.R. Tanvir (Univ. Leicester), V. Testa
(INAF/OAR), E. Palazzi (INAF/IASF Bo), A.O. Jaunsen (Univ. Oslo), C.C.
Thoene (DARK/NBI), J. Hjorth (DARK/NBI), P.M. Vreeswijk (ESO), report:
We have observed the optical afterglow of GRB 070411 (Moretti et al., GCN
6267), using the NOT, VLT, TNG, and WHT telescopes, in the R band.
Observations were carried out at several epochs, between 0.04 and 8 days
after the burst. Analysis of the light curve reveals a clear steepening at
~1 day after the GRB. The late-time slope alpha ~ 1.4 is well constrained
by our measurements (see also Ferrero et al., GCN 6319), and has a value
flatter than expected from post-jet break models (alpha >~ 2).
We encourage observations at X-ray wavelengths to test for the presence of
any break in the X-ray light curve.
We acknowledge support from the observers and the staff at the NOT, VLT,
TNG, and WHT telescopes.
GCN Circular 6346
Subject
GRB 070411, deep LBT photometry
Date
2007-04-23T18:37:00Z (18 years ago)
From
Peter Garnavich at U of Notre Dame <pgarnavi@nd.edu>
J. Prieto (Ohio State), P. Garnavich (Notre Dame), J. Hill (LBTO/UAz),
X. Fan, J. Harris (U Ariz), X. Dai, P. Martini, K. Z. Stanek (Ohio State),
R. M. Wagner (LBTO/OSU), J. Rhoads (Ariz State),
S. Herbert-Fort (UAz) report:
The Large Binocular Telescope (LBT) imaged the position of the GRB 070411
afterglow (Moretti et al, GCN 6267; Kann et al. GCN 6268) with the
LBC-blue CCD camera (http//lbc.mporzio.astro.it) and 8.4-m SX mirror on
2007 April 15.145 (UT). Ten dithered, 200 second exposures were obtained
with the Sloan-r filter in 0.7" seeing. A point source within 0.1" of
the Swift/UVOT position is clearly detected in each image.
In the combined image we find the afterglow to be 5.431 magnitudes
fainter than the unsaturated star at RA=7:09:23.35 DEC=1:04:09.98
and listed in the USNO-B catalog at R2=18.52 mag. An out-of-focus
image shows that this star is 0.916 mag fainter than the star
used by Berger, Modjaz & Garg et al. (GCN 6278) implying the two
calibrations are consistent. So we find the afterglow brightness to
be r=23.95+/-0.05 mag. 3.30 days after the burst.
Image subtraction of individual frames shows no significant
variability (<0.10 mag) on time-scale between 4 minutes and
an 40 minutes.
The fading between the Berger et al. observation and the LBT
image is consistent with a power-law decay index of 1.0, but
note the possibility of a break reported by Malesani et al.
(GCN 6343).
The LBT image can be found at:
http://www.nd.edu/~pgarnavi/grb070411/grb070411_LBT.jpg
The LBT is an international collaboration among institutions in the
United States, Italy and Germany. The LBT Corporation partners are:
* The University of Arizona on behalf of the Arizona university system
* Istituto Nazionale di Astrofisica, Italy
* LBT Beteiligungsgesellschaft, Germany, representing the Max Planck
Society, the Astrophysical Institute Potsdam, and Heidelberg University
* The Ohio State University
* The Research Corporation, on behalf of The University of Notre Dame,
University of Minnesota and University of Virginia
This message may be cited
GCN Circular 6349
Subject
GRB 070411 : Planned XMM-Newton observation
Date
2007-04-25T15:07:08Z (18 years ago)
From
Norbert Schartel at XMM-Newton/ESA <too@xmm.vilspa.esa.es>
XMM-Newton will observe GRB 070411 at location
(RA=07h 09m 19.93s DEC=+01d 03' 52.6", J2000),
starting at 09:45 UT, on April 28, 2007,
for an exposure of 20000 seconds.
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GCN Circular 6350
Subject
GRB 070411: Late-time Keck imaging
Date
2007-04-25T18:49:50Z (18 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
D. A. Perley, J. S. Bloom, R. J. Foley, and D. Kocevski (UC Berkeley)
report:
On the night of 2007 April 16 (UT) we imaged the field of GRB 070411
(Moretti et al, GCN 6267) with Keck I / LRIS, in a series of g- and
R-band exposures starting at 06:19 UT, 4.42 days after the GRB trigger
under poor seeing conditions. The afterglow (GCN 6267; Kann et al, GCN
6268) is detected in a stacked image. Calibrating relative to the same
USNO-B star used by Garnavich et al (GCN 6346) at RA=7:09:23.35
DEC=1:04:09.98, we measure an afterglow magnitude of R = 24.78 +/- 0.26.
GCN Circular 6351
Subject
GRB 070411, further deep LBT photometry
Date
2007-04-26T21:50:07Z (18 years ago)
From
Peter Garnavich at U of Notre Dame <pgarnavi@nd.edu>
P. Garnavich (Notre Dame), J. Prieto (Ohio State), J. Hill (LBTO/UAz),
X. Fan (U Ariz), X. Dai, K. Z. Stanek (Ohio State),
R. M. Wagner (LBTO/OSU), J. Rhoads (Ariz State),
J. Bechtold (UAz), R. Gredel (MPIA), A. Grazian (Rome) report:
The Large Binocular Telescope (LBT) imaged the position of the GRB 070411
afterglow (Moretti et al, GCN 6267; Kann et al. GCN 6268) with the
LBC-blue CCD camera (http//lbc.mporzio.astro.it) and 8.4-m SX mirror on
2007 April 22.14 (UT). Ten dithered, 200 second exposures were obtained
with the Sloan-r filter in poor seeing and a bright sky background. No
afterglow is detected and we estimate a 3-sigma upper-limit of r>25.3 mag.
Extrapolating the power-law decay found by Prieto et al. (GCN 6346) to
10.3 days after the burst, we expected an afterglow brightness of
r=25.1+/-0.2 mag. Our non-detection is therefore marginal confirmation
of a break in the light curve as reported by Malesani et al. (GCN 6343).
The Keck observation (Perley et al GCN 6350) on day 4.4 also supports an
increase in the decay rate.
The LBT is an international collaboration among institutions in the
United States, Italy and Germany. The LBT Corporation partners are:
* The University of Arizona on behalf of the Arizona university system
* Istituto Nazionale di Astrofisica, Italy
* LBT Beteiligungsgesellschaft, Germany, representing the Max Planck
Society, the Astrophysical Institute Potsdam, and Heidelberg University
* The Ohio State University
* The Research Corporation, on behalf of The University of Notre Dame,
University of Minnesota and University of Virginia
This message may be cited
GCN Circular 6487
Subject
GRB 070411: TAROT Calern observatory optical observations
Date
2007-06-08T05:50:21Z (18 years ago)
From
Alain Klotz at CESR-CNRS <Alain.Klotz@free.fr>
Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report:
We imaged the field of GRB 070411 detected by SWIFT
(trigger 275087) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.
Analysis of this burst is late due to a technichal
problem.
The observations started 45.6s after the GRB trigger
(5.7s after the notice) when the burst was still active.
The elevation of the field decreased from
from 33 degrees above horizon and weather conditions
were poor (cloudy).
The date of trigger : t0 = 2007-04-11T20:12:33.120
The first image is trailed with a duration of 60.0s
(see the description in Klotz et al., 2006, A&A 451, L39).
We do not detect the UVOT candidate position (Moretti
et al., GCN 6267) with a limiting magnitude of:
t0+45.6s to t0+105.6s : R > 14.6
The second image is 30.0s exposure in tracking mode:
t0+112.6s to t0+142.6s : R > 15.5
Further images have no significant higher limiting
magnitude.
Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.
This message may be cited.