GRB 080605
GCN Circular 7864
Subject
GRB 080605: TLS 3rd Epoch - Source Confusion
Date
2008-06-09T01:24:01Z (17 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann, U. Laux & S. Ertel (TLS Tautenburg) report:
We obtained further images of the Swift GRB 080605 (Sbarufatti et al., GCN
7828). A 300 second Ic frame obtained under excellent observing conditions
shows the field remains unchanged in comparison to the second epoch as
well as the final images of the first epoch (Kann et al., GCN 7845).
Recently, Yoshida et al. (GCN 7863) also claimed detection of a plateau
phase. Clemens et al. (GCN 7851), on the other hand, report a clear fading
of the afterglow, as well as only a moderately red color in comparison to
Kann et al. (GCN 7845), which can possibly be explained by the moderate
Galactic reddening alone.
Comparison with a multicolor finding chart taken by GROND (C. Clemens,
priv. comm.) reveals the culprit: source confusion. Near the position of
the afterglow, there are in total three sources, all seemingly stellar in
GROND images, along a line. The star to the southeast (Source #1) was
immediately reported (Sbarufatti et al., GCN 7828, Kann et al., GCN 7829)
and is clearly visible in the DSS. To the northwest, there is another
source (Source #2), also clearly visible in the DSS. An inspection of the
DSS IR frame reveals that #2 is hardly visible at all, but a new source
(Source #3), inbetween #1 and #2, now becomes clearly visible. This source
is extremely red, possibly a red dwarf, and it is THIS source which begins
to dominate the photometry reported in Kann et al. (GCN 7845) (and
presumably Yoshida et al., GCN 7863), which is mostly I band. The small
offset from source #1 lead us to believe that this is the afterglow (and
explained the puzzling observation that it seemed to slightly shift
position).
Therefore, we retract the identification of a plateau phase of the
afterglow of GRB 080605, as well as the claim of extreme redness and the
resulting high lumonisity around 1 day in the observer frame. On the other
hand, the afterglow IS clearly detected on the early I band frames of the
TLS RRM observation, as well as in the R band and a stacked V band frame.
The early photometry, which leads to a decay slope of alpha ~ 1, is still
valid. Image subtraction will have to be performed to see how many
detections we have actually gotten.
This message may be cited.
GCN Circular 7863
Subject
GRB080605: optical observation with the MITSuME-OAO telescope
Date
2008-06-09T00:24:33Z (17 years ago)
From
Michitoshi Yoshida at Okayama Astrophysical Obs <yoshida@oao.nao.ac.jp>
M. Yoshida, K. Yanagisawa, D. Kuroda, Y. Shimizu, S. Nagayama,
H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:
We performed optical imaging observation (Rc, and Ic) of the field
of GRB 080605 (Sbarufatti et al., GCN 7828) with 50cm MITSuME
telescope at Okayama Astrophysical Observatory June 6 2008 UT.
We detected a point source at the UVOT position of the optical
afterglow (Kuin et al., GCN 7844). Differential photometry was
made using a USNO B1.0 star, USNO-ID 0940-0289655 (Kann et al.,
GCN 7845). The Ic-band magnitude of the source was almost constant
from T-T0 = 0.516 to 0.756. The source is about 1.5 magnitude
fainter in Rc-band than in Ic-band. These results are consistent
with other reports (Kann et al., GCN 7845, Rumyantsev et al.,
GCN 7857).
MITSuME observation start: 2008-06-06 11:35:11 UT
mid-UT T-T0(days) exp-T Ic
(2008-06-06)
---------------------------------------------------
12:11:27 0.516314 60 min 19.03 +/- 0.38
12:48:05 0.541753 60 min 19.00 +/- 0.29
14:00:54 0.592315 60 min 18.85 +/- 0.18
15:15:44 0.644288 60 min 19.03 +/- 0.22
16:30:50 0.696429 60 min 18.82 +/- 0.21
17:56:24 0.755856 80 min 18.87 +/- 0.30
---------------------------------------------------
mid-UT
(2008-06-06) T-T0(days) ext-T Rc
---------------------------------------------------
15:52:20 0.669745 120 min 20.58 +/- 0.32
---------------------------------------------------
GCN Circular 7857
Subject
GRB 080605: optical observations
Date
2008-06-07T19:42:52Z (17 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB
follow-up collaboration:
We observed the optical afterglow of Swift GRB 080605 (Sbarufatti et al.,
GCN 7828) in second epoch on June 06 with Zeiss-1000 (Simeiz) telescope of
CrAO observatory with favorable weather conditions and seeing about 2". Our
first epoch astrometry of the source (Rumyantsev et al., GCN 7833) is in
agreement with refined UVOT position of GRB080605 (Kuin et al., GCN 7844).
The observation of the first epoch started 8 minute after burst onset
(Rumyantsev et al., GCN 7833) was performed under descending weather
conditions with seeing about 3". Improved photometry of the first epoch
observation as well as observation on June 6 is based on USNO-B1.0 star RA
(J2000) = 17 28 29.92, Dec.(J2000) = +04 00 36.5, assuming R=15.90, I=14.54:
T0+ Exposure, Filter, mag,
(d,mid time)
0.006251 120 R 18.04 +/- 0.08
0.007698 120 R 18.43 +/- 0.06
0.009457 120 R 18.62 +/- 0.06
0.010985 120 R 18.63 +/- 0.23
0.015163 120 R 18.93 +/- 0.23
0.018068 120 R >19.04
0.019504 120 R 18.86 +/- 0.20
0.026031 120 I 18.12 +/- 0.28
0.033219 120 V >17.50
0.034654 120 V >18.20
0.904028 34x120 R 21.13 +/- 0.06
The photometry is still preliminary and not corrected for Galaxy extinction
and might be affected by the bright, nearby star.
It is evident that the source is faded between June 5 and June 6. Power law
index of early afterglow decay ~0.8 is compatible with index obtained in
I-band (Kann et al., GCN 7845). However our absolute photometry in R-band
have a significant offset in comparison with early observations by Kann et
al. (GCN 7845) and compatible with photometry of Gomboc et al. (GCN 7831).
Our early observation suggests R-I ~ 1.2, however we caution the color of
the afterglow is also depending on photometry which is affected by bright,
nearby star.
The message may be cited.
GCN Circular 7854
Subject
Konus-Wind observation of GRB 080605
Date
2008-06-07T16:02:39Z (17 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and
T. Cline on behalf of the Konus-Wind team report:
The bright GRB 080605 (Swift-BAT trigger #313299: Sbarufatti et al., GCN
7828, Cummings et al., GCN 7839) triggered Konus-Wind at T0=85682.336 s
UT (23:48:02.336).
The burst light curve shows a multipeaked structure with a total
duration of ~20s.
As observed by Konus-Wind the burst
had a fluence of 3.02(-0.12, +0.13)x10^-5 erg/cm2,
and a 16-ms peak flux measured from T0+7.984 s
of (1.60 +/- 0.33)x10^-5 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).
The time-integrated spectrum of the burst
(from T0 to T0+18.944 s) can be fitted (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 = -1.03 +/- 0.07,
and Ep = 252(-17, +20) keV (chi2 = 57.2/61 dof).
Fitting by GRBM (Band) model yields:
the low-energy photon index is alpha = -1.02 +/- 0.08,
the high energy photon index beta < -2.75,
the peak energy Ep = 246(-18, +23) keV (chi2 = 56.7/60 dof).
The spectrum of the most intense peak (from T0+7.168 s to T0+8.960 s)
is well fitted (in the 20 keV - 2 MeV range)
by a power law with exponential cutoff model
with alpha = -0.94 +/- 0.10
and Ep = 333(-34, +42) keV (chi2 = 60.6/54 dof).
Fitting by GRBM (Band) model yields:
the low-energy photon index is alpha = -0.87(-0.12, +0.13),
the high energy photon index beta = -2.58(-0.84, +0.31),
the peak energy Ep = 297(-40, +46) keV (chi2 = 56.6/53 dof).
All the quoted errors are at the 90% confidence level.
Assuming z = 1.640 (Jakobsson et al., GCN 7832) and a standard
cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27, Omega_\Lambda =
0.73, the isotropic energy release is E_iso ~2.1x10^53 erg,
the maximum luminosity is (L_iso)_max ~3.0x10^53 erg/s, and
Ep_rest ~660 keV.
The Konus-Wind light curve of this GRB is available
at http://www.ioffe.rssi.ru/LEA/GRBs/GRB080605_T85682/
GCN Circular 7851
Subject
GRB 080605: GROND 2nd epoch observations
Date
2008-06-07T09:44:28Z (17 years ago)
From
Christian Clemens at MPE <cclemens@mpe.mpg.de>
C. Clemens, A. Kupcu Yoldas, J. Greiner, T. Kruehler, A. Yoldas (all MPE
Garching) and G. Szokoly (Eoetvoes Univ., Budapest and MPE Garching) report
on behalf of the GROND team:
We observed the field of GRB 080605 for a second time at 02:43 UT on June 7th,
2008 about 1.12 days after the GRB trigger with 25 mins of effective
exposures in g'r'i'z'.
We still detect the bright afterglow within the refined 0.5'' Swift-UVOT error
circle (Kuin et al., GCN #7844) to the following preliminary magnitudes of
r' = 22.3,
i' = 21.7 and
z' = 21.4
with typical errors of +/- 0.1. Given magnitudes are calibrated against
USNO-B1 field stars and might be affected by the bright, nearby star.
This indicates a clear fading of the optical afterglow compared to our first
epoch observations (C. Clemens et al., GCN #7834).
Please note, that no correction for the galactic foreground reddening of
E(B-V) = 0.136 mag (Schlegel et al., 1998) has been applied.
GCN Circular 7845
Subject
GRB 080605: TLS RRM Analysis, Plateau/Rebrightening, Red OT
Date
2008-06-07T02:27:14Z (17 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann, U. Laux and S. Ertel (TLS Tautenburg) report:
We continue observations of the afterglow of GRB 080605 (independently
discovered by Sbarufatti et al., GCN 7828, Kann et al., GCN 7829, and
Gomboc et al., GCN 7831). We acquired one 300 sec image each in V, R, and
I around 0.95 days after the GRB, and further imaging 0.1 days later until
dawn. Astonishingly, the afterglow is still clearly visible in R and I
bands.
As mentioned in the above-cited GCNs, the afterglow is close to a star and
affected by its PSF in images with low-quality seeing or large pixel
scale, such as the TLS camera. To obtain a qualitative description of the
afterglow evolution, we perform aperature photometry in a 3 pixel
aperature, and derive the aperature correction for each image by comparing
the counts for a reference star in the 3 pixel aperature with that in a 7
pixel (which is typically seeing-matched) aperature. As a reference star,
we use the star to the south of the afterglow, USNOB1.0 ID 0940-0289655 at
(catalog position): RA = 17:28:29.920, Dec. = +04:00:36.51, which has R2 =
15.90 mag, I = 14.54 mag. We derive the following magnitudes for selected
images in the I band (the error is estimated to be 0.1 magnitudes in all
cases):
dt I
0.00478791 16.74
0.00674681 17.18
0.00869923 17.36
0.01064872 17.61
0.01849396 18.19
0.02433042 18.19
0.05922051 18.48
0.96109933 18.51
1.05275325 18.71
The early afterglow decay (0.00479 to 0.01849 days) is well-described by a
power-law with decay slope alpha=0.97. After this, the afterglow decay
seems to flatten. Between 0.06 days and 0.95 days, the afterglow magnitude
remains unchanged, indicating a plateau phase. As the afterglow has
resumed its decay 0.1 days later, this probably implies that the
afterglow underwent a strong rebrightening which we caught after the
peak. This is reminiscent of GRB 071003, which lies at a very similar
redshift (Perley et al. 2008, ApJ, submitted, arXiv:0805.2394) of ~ 1.6
(Jakobsson et al., GCN 7832).
Furthermore, we determined the R band magnitude at two epochs:
dt R
0.01655957 19.87
0.95457023 20.75
Corrected for the moderate Galactic foreground extinction of E(B-V) =
0.136, we find R - I ~ 2 mag. This is a very red color for an afterglow,
indicating strong internal reddening due to dust. We caution that the
USNOB1.0 comparison star may have incorrect photometry, on the other hand,
a simple image comparison shows that the R band magnitude is much fainter
than the I band magnitude.
The strong rebrightening combined with the large correction for dust
extinction that is needed imply that this is an intrinsically extremely
luminous afterglow. Further follow-up, especially in the NIR bands, is
highly encouraged.
This message may be cited.
GCN Circular 7844
Subject
GRB 080605: Swift-UVOT refined analysis
Date
2008-06-06T20:45:57Z (17 years ago)
From
Paul Kuin at MSSL <npkuin@googlemail.com>
N. P. M. Kuin (MSSL/UCL), B. Sbarufatti (INAF-IASFPA), F. Marshall (GSFC),
and P.Schady (MSSL/UCL), report on behalf of the Swift UVOT team
The Swift UltraViolet/Optical Telescope (UVOT) began observations
of GRB 080605, on June 5, 2008, at 23:49:19 UT, 82 seconds after
the initial Swift BAT trigger (Mangano et al., GCN Circ. 7794), and
started the finding chart exposure in the white filter at 102
seconds after the trigger.
The refined uvot position of GRB080605 is RA=262.12522, Dec=+4.01555
deg.(= 17:28:30.05 +04:00:55.97), with an accuracy of 0.5", consistent
with the positions reported in GCN Circ. 7830 (Holland et al.) and
7835 (Goad et al.).
The GRB is found close (about 4" distant) to a star, which may cause
an error in the measured flux, especially at later times. For this
analysis we use a small 2" aperture which which reduces the
contamination, and apply a standard aperture correction. We note that
the DSS image indicates the presence of a weak, possibly extended
source near the position of the afterglow.
The magnitudes with 1-sigma errors for GRB080605 are given below
for the initial observation sequence.
Filter Tstart(s) Tstop(s) Exp(s) Magnitude
wh 102 201 98.2 18.11 +/- 0.06
v 208 607 393.5 18.53 +/- 0.11
wh 858 957 98.2 20.02 +/- 0.17
uvm2 615 788 38.9 >18.38 (3 sigma UL)
uvw1 639 813 38.9 >18.95 (3 sigma UL)
uvw2 720 739 19.5 >18.16 (3 sigma UL)
b 27679 28264 571.7 21.10 +/- 0.27
u 18432 41856 550.7 21.17 +/- 0.43
The values quoted above are on the UVOT Photometric System
(Poole et al, 2008, MNRAS 383,627). They are not corrected for the
expected galactic reddening of E(B-V) = 0.137 in the direction of
the burst (Schlegel et al. 1998).
GCN Circular 7841
Subject
GRB 080605, Swift-BAT refined analysis
Date
2008-06-06T17:44:56Z (17 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
J. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC),
E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
M. Stamatikos (GSFC/ORAU), B. Sbarufatti (INAF-IASFPA), J. Tueller (GSFC),
T. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 080605 (trigger #313299)
(Sbarufatti, et al., GCN Circ. 7828). The BAT ground-calculated position is
RA, Dec = 262.130, 4.010 deg, which is
RA(J2000) = 17h 28m 31.1s
Dec(J2000) = +04d 00' 35.6"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 41%.
The mask-weighted light curve shows a cluster of overlapping peaks
starting at ~T-3 sec, the largest peak at ~T+8 sec, and all ending at ~T+70 sec.
At the 1-2 sigma level, there is appears to be persistant emmission
in the T+300 to T+700 sec range. T90 (15-350 keV) is 20 +- 1 sec
(estimated error including systematics).
The time-averaged spectrum from T-5.5 to T+30.0 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 1.11 +- 0.14,
and Epeak of 223 +- 133 keV (chi squared 28.10 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 1.33 +- 0.02 x 10^-5 erg/cm2
and the 1-sec peak flux measured from T+7.57 sec in the 15-150 keV band is
19.9 +- 0.6 ph/cm2/sec. A fit to a simple power law gives a photon index
of 1.36 +- 0.03 (chi squared 37 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/313299/BA/
GCN Circular 7839
Subject
GRB 080605, Swift-BAT refined analysis
Date
2008-06-06T17:37:12Z (17 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
J. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC),
E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
M. Stamatikos (GSFC/ORAU), B. Sbarufatti (INAF-IASFPA), J. Tueller (GSFC),
T. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 080605 (trigger #313299)
(Sbarufatti, et al., GCN Circ. 7828). The BAT ground-calculated position is
RA, Dec = 262.130, 4.010 deg, which is
RA(J2000) = 17h 28m 31.1s
Dec(J2000) = +04d 00' 35.6"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 41%.
The mask-weighted light curve shows a cluster of overlapping peaks
starting at ~T-3 sec, the largest peak at ~T+8 sec, and all ending at ~T+70 sec.
At the 1-2 sigma level, there is appears to be persistant emmission
in the T+300 to T+700 sec range. T90 (15-350 keV) is 20 +- 1 sec
(estimated error including systematics).
The time-averaged spectrum from T-5.5 to T+30.0 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 1.11 +- 0.14,
and Epeak of 223 +- 133 keV (chi squared 28.10 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 1.33 +- 0.02 x 10^-5 erg/cm2
and the 1-sec peak flux measured from T+7.57 sec in the 15-150 keV band is
19.9 +- 0.6 ph/cm2/sec. A fit to a simple power law gives a photon index
of 1.36 +- 0.03 (chi squared 37 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/313299/BA/
GCN Circular 7838
Subject
GRB 080605: Swift-XRT refined analysis
Date
2008-06-06T17:22:59Z (17 years ago)
From
Boris Sbarufatti at INAF-IASF-Pa <sbarufatti@ifc.inaf.it>
B. Sbarufatti, V. Mangano, V. La Parola (INAF-IASF Pa) report on
behalf of the Swift-XRT team
The XRT began observations of GRB 080605 (trigger=313299,
Sbarufatti et al., GCN circ. 7828) started on 2008 May 05 at 23:49:36 UT,
97 s after the BAT trigger. The data consist of 642 s in Windowed Timing
mode and 4.3 ks s in Photon Counting mode.
The light curve is described by a powerlaw with initial slope
0.65 (+/-0.05) until T+ 280s (+90, - 45), at which point the decay
steepens to an index 1.32 (+/-0.03).
The spectrum of the WT mode data can be fitted by a powerlaw with
photon index 1.78 (+/- 0.04) and an intrinsic absorbing column of
6.6 (+/-0.9)E21 cm^-2 at z=1.6398 (Jakobsson et al., GCN circ. 7832),
in excess over the Galactic value of 6.67E20 cm^-2.
The observed (unabsorbed) flux is 7.5 (8.1)E-10 erg cm^-2 s^-1.
The first orbit PC mode spectrum (379 s of exposure) can be
fit by a powerlaw with photon index 1.6 (+/- 0.2) and an
intrinsic absorbing column of 4.8 (+/-4)E21 cm^-2. The observed
(unabsorbed) flux is 3.0 (3.3)E-10 erg cm^-2 s^-1.
The countrate to flux conversion factor is 4.87e-11 erg cm^-2 s^-1.
The predicted countrate 24 h after the trigger is 1.6E-2 counts/s,
equivalent to an observed flux of 7.8E-13 erg cm^-2 cts^-1.
This circular is an official product of the Swift-XRT team.
GCN Circular 7837
Subject
GRB080605: observation by BOOTES
Date
2008-06-06T12:36:57Z (17 years ago)
From
Martin Jelinek at Inst.Astrophys.Andalucia,Granada <mates@iaa.es>
M. Jelinek, A.J.Castro-Tirado, J. Gorosabel (IAA CSIC Granada),
Petr Kubanek (GACE Valencia), S. Vitek (FEL CVUT Praha),
A. de Ugarte Postigo (ESO Santiago), on behalf of a larger
Collaboration:
report:
"We observed the optical afterglow of GRB 080605 (Kann et al.
GCN 7829, Sbarufatti et al. GCN 7828, Gomboc et al. GCN 7831)
with the 30cm BOOTES-1B and with the 60cm BOOTES-2/TELMA
robotic telescopes in southern Spain.
The sequence of observations started 43s after the GRB trigger.
We clearly detect a 15th mag transient outshining the nearby star
in R-band (BOOTES-2/TELMA) and without filter (BOOTES-1B). "
GCN Circular 7836
Subject
GRB 080605: MASTER VWF 46 s AT observation
Date
2008-06-06T11:52:33Z (17 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <gcncirc@observ.inetcomm.ru>
MASTER-Net Team:
D.Kuvshinov, V. Lipunov, V.Kornilov, E.Gorbovskoy,
A.Belinski, N.Shatskiy, N.Tyurina,
Sternberg Astronomical Institute, Moscow Union 'Optic'
A. Tlatov, I.Golubov
Kislovodsk Solar Station of the Pulkovo observatory
V.Krushinski, I.Zalognikh
Ural State University, Kourovka
S.Yazev, K.Ivanov
Irkutsk State University
MASTER Very Wide Field Camera located at Kislovodsk Solar Station
(http://observ.pereplet.ru, D=50 mm, 1015 square degrees, 35'' per pix)
has moved to the Swift-BAT trigger 313299 (23:47:57 UT) and it has taken a
series of 5s exposures starting 46s after the GRB time and 12 s after
notice arrivel time at 23:48:43 UT under good weather condition, but
large zenit distance.
These unfiltered images are calibrated relative to USNO A2.0 (R).
There is no OT was found inside Swift error box
(B. Sbarufatti, S. D. Barthelmy et al., GCN Circ 7828).
T-Tgrb Mean Time Limit Coadd? Note
46s 48.5s >9.0 no moving
51s 53.5s >10.0 no
51s 56.0s >10.2 2
51s 76.0s >11.0 10
51s 101.0s >11.5 20
The message can be cited.
mailto: lipunov@sai.msu.ru
PS. AT = After Trigger
GCN Circular 7835
Subject
GRB 080605: Enhanced Swift-XRT position
Date
2008-06-06T11:41:27Z (17 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 426 s of overlapping XRT Photon Counting mode and UVOT
data for GRB 080605, 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 = 262.12533, +4.01608 which is equivalent
to:
RA (J2000): 17h 28m 30.08s
Dec (J2000): +04d 00' 57.9"
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
http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an
extension of this method.
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 7834
Subject
GRB 080605: GROND detection of the optical afterglow candidate
Date
2008-06-06T04:30:38Z (17 years ago)
From
Christian Clemens at MPE <cclemens@mpe.mpg.de>
C. Clemens, T. Kruehler, J. Greiner, A. Kupcu Yoldas, A. Yoldas (all MPE
Garching) and G. Szokoly (Eoetvoes Univ., Budapest and MPE Garching) report
on behalf of the GROND team:
We observed the field of GRB 080605 (Swift trigger 313299; Sbarufatti et al.,
GCN #7828) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,
PASP 120, 405) mounted at the 2.2m ESO/MPI telescope at La Silla Observatory
(Chile).
Observations started at 01:10:59 UT on June 6th, 2008, 83 mins after the GRB
trigger, and are continuing.
We found a single and relatively bright point source within the 1.0''
Swift-UVOT error circle reported by Holland et al. (GCN #7830) at
RA (J2000.0) = 17h 28m 30.05s
DEC (J2000.0) = +04d 00' 56.2"
with a typical uncertainty of 0.8", which is consistent with the sources
reported by Kann et al. (GCN #7829) and Gomboc et al. (GCN #7831).
Based on 460 s and 1500 s of effective exposures taken 1.65 hrs and 2.78 hrs
after the trigger, we estimate preliminary magnitudes of
r' = 20.3 and i' = 19.4, as well as
r' = 20.7 and i' = 19.9
with typical errors of +/- 0.1. (Given magnitudes are calibrated against
USNO-B1 field stars and might be affected by the bright, nearby star.)
This indicates a clear fading of the source, which we therefore suggest to be
the optical afterglow of GRB 080605.
GCN Circular 7833
Subject
GRB080605: optical observations
Date
2008-06-06T04:22:14Z (17 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB
follow-up collaboration:
We observed the optical afterglow (Kann, et al., GCN 7829; Holland et al.,
GCN 7830; Gomboc et al., GCN 7831) of Swift GRB 080605 (Sbarufatti et al.,
GCN 7828) in R and I bands on June 05 Zeiss-1000 (Simeiz) telescope of CrAO
observatory under not optimal weather conditions. Based on USNO-B1.0 star
RA (J2000) = 17 28 29.92, Dec.
(J2000) = +04 00 36.5, R2=15.90 we estimated brightness of the optical
afterglow in first frames:
UT, Exposure, R_mag,
(start time)
2008-06-05T23:55:58 120 s 17.9
2008-06-06T00:00:34 120 s 18.4
During observations the afterglow is clearly faded.
Coordinates of the afterglow with uncertainties of 0.3":
RA(2000): 17 28 30.01
Dec(2000): +04 00 56.4
A finding chart can be found at
http://grb.rssi.ru/GRB080605/grb080605_080605_z1000.gif
The message may be cited.
GCN Circular 7832
Subject
GRB 080605: VLT redshift
Date
2008-06-06T03:56:15Z (17 years ago)
From
Pall Jakobsson at U Hertfordshire <P.Jakobsson@herts.ac.uk>
Pall Jakobsson (U. Hertfordshire), Paul M. Vreeswijk,
Dong Xu and Christina C. Thoene (DARK, NBI) report on behalf
of a larger collaboration:
Using FORS2 on the Very Large Telescope, we have obtained
a 10 min spectrum (grism 300V) of the optical afterglow of
GRB 080605 (Sbarufatti et al., GCN 7828). The acquisition
image shows it to have R = 20.4 on June 6.063 (1.7 hours
post burst).
A firm upper limit of z < 2.1 can be placed on the redshift
of GRB 080605 from the lack of Ly-alpha forest lines in the
spectrum of the afterglow.
The spectrum is rich in absorption features, including Si II,
C IV, Al II, Al III, Zn II, Fe II, Mg II and Mg I, corresponding
to a redshift of z = 1.6398 +/- 0.0006.
We thank the Paranal staff for excellent support, especially
Linda Schmidtobreick.
GCN Circular 7831
Subject
GRB 080605: Liverpool Telescope optical afterglow candidate
Date
2008-06-06T00:40:18Z (17 years ago)
From
Andreja Gomboc at LT,ARI,Liverpool JMU <ag@astro.livjm.ac.uk>
A. Gomboc (U. Ljubljana), A. Melandri, R.J. Smith, C.G. Mundell, I.A.
Steele, D. Bersier, S. Kobayashi, D. Carter, M. Burgdorf, M.F. Bode
(Liverpool JMU), C. Guidorzi (INAF-OAB) report:
The Liverpool Telescope (La Palma) automatically reacted to the Swift
trigger 313299 and started observing the field 3 min after the trigger.
We find an un-catalogues source at
RA 17:28:29.9,
dec +04:00:55.0
consistent with the XRT position.
The magnitude of the source is R=18.3 at 11.3 min after the trigger.
GCN Circular 7830
Subject
GRB 080605: Swift/UVOT Position of the Optical Afterglow
Date
2008-06-06T00:27:40Z (17 years ago)
From
Stephen Holland at USRA/NASA/GSFC/SSC <sholland@milkyway.gsfc.nasa.gov>
S. T. Holland (CRESST/USRA/GSFC) and B. Sbarufatti (INAF-IASFPA)
report on behalf of the Swift Team:
Swift/UVOT began observing the field of GRB 080605 (Sbarufatti et
al. 2008, GCN Circ. 7828) with a 99 s white exposure starting 104 s
after the BAT trigger. The preliminary Swift/UVOT position of the
optical afterglow candidate is
RA(J2000.0) = 17:28:30.07
Dec(J2000.0) = +04:00:56.0
with an estimated position uncertainty of 1.0 arcsec. There is a
known source (USNO-B1.0 940-028965) 3 arcsec from this position.
GCN Circular 7829
Subject
GRB 080605: TLS RRM Afterglow
Date
2008-06-06T00:17:51Z (17 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
This is a multi-part message in MIME format.
--bound1212711210
Content-Type: text/plain
Content-Transfer-Encoding: 7bit
D. A. Kann, U. Laux, S. Klose, S. Ertel (TLS Tautenburg) and J. Greiner (Garching) report:
We observed the location of Swift GRB 080605 with the TLS Tautenburg 1.34m Schmidt telescope in RRM Mode (Klose et al., GCN 3609).
At the in-flight XRT position, in a 120 sec Ic band frame, we detect a new source not present in the DSS at:
RA (J2000) = 17:28:29.96
Dec. (J2000) = +04:00:57.5
The source is blended with a star to the southeast but clearly discernible.
We propose this to be the afterglow of GRB 080605. Spectroscopy is encouraged.
This message may be cited.
--bound1212711210--
GCN Circular 7828
Subject
GRB 080605: Swift detection of a burst with an optical afterglow
Date
2008-06-06T00:13:48Z (17 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
B. Sbarufatti (INAF-IASFPA), S. D. Barthelmy (GSFC),
D. N. Burrows (PSU), N. Gehrels (NASA/GSFC),
S. T. Holland (CRESST/USRA/GSFC), V. La Parola (INAF-IASFPA),
V. Mangano (INAF-IASFPA), C. B. Markwardt (CRESST/GSFC/UMD),
D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (NASA/UMBC),
T. N. Ukwatta (GSFC/GWU) and D. E. Vanden Berk (PSU) report on behalf
of the Swift Team:
At 23:47:57 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 080605 (trigger=313299). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 262.127, +4.002 which is
RA(J2000) = 17h 28m 31s
Dec(J2000) = +04d 00' 06"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows multiple overlapping
peaks lasting at least to T+8 sec (at which the TDRSS lightcurve is
truncated). The peak count rate was ~17000 counts/sec (15-350 keV),
at ~1 sec after the trigger.
The XRT began observing the field at 23:49:28.2 UT, 90.4 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 262.1249, +4.0153 which is equivalent to:
RA(J2000) = 17h 28m 29.9s
Dec(J2000) = +04d 00' 55.0"
with an uncertainty of 5.0 arcseconds (radius, 90% containment). This
location is 48 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.
The UVOT detects a new source within the XRT error circle. We are unable to
obtain a position or magnitude at this time. The source is very close to a
known source in the DSS. Further information will be provided when it is available.
Burst Advocate for this burst is B. Sbarufatti (sbarufatti 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.)