GRB 050904
GCN Circular 3910
Subject
GRB050904: Swift-BAT detection of a probable burst
Date
2005-09-04T03:07:21Z (20 years ago)
From
Scott Barthelmy at NASA/GSFC <Scott@lheamail.gsfc.nasa.gov>
J. Cummings (GSFC/NRC), L. Angelini (GSFC), S. Barthelmy (GSFC), A. Cucchiara (PSU),
N. Gehrels (GSFC), C. Gronwall (PSU), S.T. Holland (GSFC), V. Mangano (INAF-IASF),
F. Marshall (GSFC), C. Pagani (PSU), D. Palmer (LANL)
on behalf of the Swift team:
At 01:51:44 UT, Swift-BAT triggered and located GRB050904 (trigger=153514).
The spacecraft slewed immediately. The BAT on-board calculated location
is RA,Dec 13.670d,+14.138d {00h 54m 41s,+14d 08' 17"} (J2000), with an
uncertainty of 3 arcmin (radius, 90% containment, stat+sys). This was a 64-sec
image trigger. The BAT light curve shows hints of emission, but it is
not possible to separate source variations from background variations
at this early stage in the analysis. Given that this is at high galactic
latitude, we believe this is a burst rather than a hard x-ray transient.
There is nothing in SIMBAD nor in the BAT Active Source list near this location.
XRT slewed promptly to the target and observation started at 01:54:25 UT
(T+161 sec) with XRT in auto state. XRT revealed an uncatalogued fading
point source at RA (J2000): 00h 54m 50.4s Dec (J2000): +14d 05' 08.5"
with an uncertainty of 6 arsec (radius), 3.9 arcmin from the BAT position.
The UVOT began observing at 01:54:28 UT, 164 s after the BAT trigger.
The UVOT image is 3 arcmin away from the XRT position, so it does not
intersect the XRT or BAT error circle. We cannot tell whether there
is an optical counterpart at this time.
We are currently in the portion of the orbits where the spacecraft does not
pass over the Malindi downlink station. Therefore, it will be 4 hours
before we have access to the full data set for the refined analyses.
GCN Circular 3911
Subject
GRB 050904: TAROT optical limits
Date
2005-09-04T07:23:23Z (20 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 050904 detected by SWIFT
(trigger 153514) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.
First image was acquired 86s after the GCN trigger.
The field had an elevation of 60 degrees above horizon
and weather conditions were good.
We detected no new source comparing our unfiltered images
with the USNO-B catalog.
From the first frame we give an early limit:
Day : 2005-09-04
UT-start UT-end (sec since GRB) Exp(s) R-mag
01:53:10.33 - 01:54:08.33 86 - 101 15 >16.0
We co-added 13 first frames and no new source
is detected:
Day : 2005-09-04
UT-start UT-end (sec since GRB) Exp(s) R-mag
01:53:10.33 - 02:00:18.74 86 - 515 360 >18.5
Limiting magnitude was estimated with the nearby USNO-B1 stars.
This message can be cited.
GCN Circular 3912
Subject
GRB050904: P60 Observations
Date
2005-09-04T07:58:41Z (20 years ago)
From
Derek Fox at PSU <dfox@astro.psu.edu>
Derek B. Fox (Penn State) and S. Bradley Cenko (Caltech) report on
behalf of a larger collaboration:
"We have imaged the BAT and XRT localization region for GRB050904
(Swift Trigger 153514; Cummings et al., GCN 3910) in a series of
exposures with the Palomar Robotic 60-inch Telescope (P60). At the
following mean epochs, and to the following limits in R- and i-band,
we identify no new sources within the XRT localization region in our
coadded images:
Time (UT) Delta Limit (mag)
===================================
05:25 +3h33m R > 20.8
05:41 +3h49m i > 19.7
===================================
Our photometric calibration is performed against the USNO-B1.0 catalog
R-band and I-band magnitudes for this field for our R- and i-filter
images, respectively.
Our observations of this field are continuing."
GCN Circular 3913
Subject
GRB 050904: SOAR/PROMPT Observations
Date
2005-09-04T10:00:28Z (20 years ago)
From
Daniel E. Reichart at U.North Carolina <reichart@physics.unc.edu>
J. Haislip, D. Reichart, E. Cypriano, S. Pizzaro, A. LaCluyze, J. Rhoads,
E. Figueredo report on behalf of the UNC team of the FUN GRB Collaboration.
We imaged the XRT localization of GRB 050904 (Cummings et al., GCN 3910)
with 4.1m SOAR at CTIO beginning about three hours after the burst. We
detect a relatively bright (J ~ 17.5 mag) and fading source within
the XRT error circle:
RA: 00 54 51.3
DEC 14 05 09.7
There is no source at this location in POSS2 or SDSS.
Near-simultaneous imaging with PROMPT reveals no source to about the POSS2
detection limit.
This suggests that the afterglow is either very extinguished or at high
redshift.
GCN Circular 3914
Subject
GRB 050904: Possible High-Redshift GRB
Date
2005-09-04T12:04:56Z (20 years ago)
From
Daniel E. Reichart at U.North Carolina <reichart@physics.unc.edu>
J. Haislip, D. Reichart, E. Cypriano, S. Pizzaro, A. LaCluyze, J. Rhoads,
E. Figueredo report on behalf of the UNC team of the FUN GRB Collaboration.
With SOAR, we have continued to image the NIR afterglow (Haislip et al.,
GCN 3913) of GRB 050904 (Cummings et al., GCN 3910) in JHK. Between 3.0
and 7.4 hours after the burst, we measure the temporal index to be -1.20.
At 7.4 hours after the burst, we measure J - K = 1.2 mag, corresponding to
a spectral index of -0.35.
Scaling the i and R limits of Fox et al. (GCN 3912) to 3.0 hours after the
burst, we measure i - J > 1.85 mag and R - J > 3.05 mag, corresponding to
spectral indexes of <-1.90 and <-3.35, respectively.
This is too steep to be explained by even heavy extinction. If
interpretted as dropout, this corresponds to 5.3 < z < 9.0 (calculated
using filter centers).
Further NIR and especially z observations are strongly encouraged.
GCN Circular 3915
Subject
GRB 050904: Environmental Constraints
Date
2005-09-04T14:36:07Z (20 years ago)
From
Daniel E. Reichart at U.North Carolina <reichart@physics.unc.edu>
D. Reichart reports on behalf of the UNC team of the FUN GRB Collaboration.
We have computed preliminary error bars on the temporal and spectral
indexes of Haislip et al. (GCN 3914). The temporal index is -1.20 +/- 0.17
and the spectral index is -0.35 +/- 0.33. This disfavors the ISM-RED and
WIND-RED cases at the 2.2 sigma confidence level, the ISM-BLUE case at the
1.3 sigma confidence level, and the WIND-BLUE case only at the 0.3 sigma
confidence level (e.g., Sari, Piran & Narayan 1998; Chevalier & Li 2000).
If the WIND-BLUE case is borne out by further observations, this suggests
an electron-energy distribution index of p = 1.9 +/- 0.2, as well as a
massive-star origin.
If the NIR afterglow is strongly extinguished, and the intrinsic spectrum
is even shallower than -0.35, or even positive, then none of the standard
cases hold. This also suggests that the afterglow is probably not strongly
extinguished, and supports the conclusion of Haislip et al. (GCN 3914) that
the sharp spectral break between the J and i bands is likely due to
dropout.
Furthermore, given that the K to J spectral index is so shallow, and the J
to i spectral index is so steep, the redshift range is probably narrower
than that implied by the J and i filter centers (5.3 < z < 9.0), and is
probably between 6 and 8. Careful modeling will better constrain this, but
z, Z and/or Y observations, preferably contemporaneous with addition NIR
observations would be most useful.
GCN Circular 3916
Subject
GRB050904: Optical Observations
Date
2005-09-04T16:19:06Z (20 years ago)
From
Aaron Price at AAVSO <aaronp@aavso.org>
Dr. D.T. Durig (Cordell-Lorenz Observatory, University of the South),
Dennis Hohman (Stone Edge Observatory) and Aaron Price report on behalf of
the AAVSO International High Energy Network on observations of the field
of GRB050409 (GCN 3910; Cummings et al.).
Durig does not detect any afterglow with SNR>3 on unfiltered images
centered at 08:30:59 UT. However, sources do exist with an SNR=3 at
locations near that reported in GCN #3913 (Haislip et al.). Locations and
magnitude:
00 54 51.38 14 04 48.9 20.0 mag
00 54 50.42 14 05 30.6 20.1 mag
00 54 51.55 14 05 28.8 20.2 mag
Full details, including a link to the FITS image is available at the
bottom of this notice.
Also, Hohman observed the field with an Rc filter centered on 06:18 UT
and does not report any afterglow to Rc=18.6. Details on his observation
are also below.
The AAVSO thanks the Curry Foundataion for their continued
support of the AVSO International High Energy Network.
Report filed on Sun Sep 4 07:54:36 2005:
Name: Dr. D. T. Durig
email: ddurig@sewanee.edu
Observer: D. T. Durig, A. P. Long, A. L. Yacko, J. L. Rouquette, J. C.
Heiss
Site: Cotrdell-Lorenz Observatory
Location: Sewanee, Tenn, USA
LatitudeLongitude: 35 12 N 85 55 W
Elevation: 600m
Scope: SCT 0.30 m
ScopeFocalRatio: f/5.9 1760 mm
CCDVendor: SBIG STL-1001E
CCDDetector: KAF-1001E
CCDSize: 1024x1024
CCDPixelScale: 2.8
CCDFOV: 48x48 full, 12x12 quater shown
Object: GRB050904
ObsDate: 2005 Sept 4
ObsMidPointTime: 08 30 59 UT
TimePerFrame: 300 sec
NumberOfFrames: 37
Filters: CR
Processing: dark, flat, register, add, 1/4 frame crop
Seeing: ~6
LimitingMag: approx. 20.5
Sky: clear but windy
afterglowmag: NA
afterglowerr: NA
compstars: 850 USNO B1.0 in Full Frame
Report: Total exposure 185 minutes (37x300 sec= 11,100 sec ). I see no
afterglow at the reported position(s) above my detection limit but there
appears to be three very dim diffuse sources nearby at
00 54 51.38 14 04 48.9 20.0 mag
00 54 50.42 14 05 30.6 20.1 mag
00 54 51.55 14 05 28.8 20.2 mag
All three are near my limiting mag with sigma equal to 3.
In the noise I measure
00 54 49.69 14 05 08.5 21.9 mag
but with sigma equal to 1.5 and below my detection limit of 20.5 mag.
A FITS image has been uploaded to
ftp://ftp.aavso.org/grb/Dr.D.T.Durig_GRB050904_2453617.99625_.fits
--------------------
Report filed on Sun Sep 4 03:36:21 2005:
Name: Dennis Hohman
email: dennishohman@adelphia.net
Observer: Dennis Hohman HDF
Site: Stone Edge Observatory
Location: Orchard Park, NY USA
LatitudeLongitude: -78 45, 42 46
Elevation: 290M
Scope: C8 200mm
ScopeFocalRatio: 1200
CCDVendor: ST7XME
CCDDetector: KAF402E
CCDSize:
CCDPixelScale: 1.55
CCDFOV: 19x13
Object: GRB050904
ObsDate: 09/04/05
ObsMidPointTime: 06:18
TimePerFrame: 240 sec
NumberOfFrames: 8
Filters: R
Processing: Darks,Flats, bias, coadd
Seeing: 4
LimitingMag: 18.6
Sky: mostly clear with occasional patchy clouds
afterglowmag:
afterglowerr:
compstars:
Report: Full error circle covered. No new object observed to a limiting
magnitude of 18.6 based USNO A2.0 catalog
comments:
A FITS image has been uploaded to
ftp://ftp.aavso.org/grb/DennisHohman_GRB050904_2453617.81691_.fits
GCN Circular 3917
Subject
GRB 050904: TAROT optical measurements
Date
2005-09-04T22:18:42Z (20 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 did not explore the location of the Haislip
et al. (GCNC 3913) source candidate in the first
analyzis reported in GCNC 3911. This source is
detected in three composited images taken by TAROT
in the 8 first minutes after GRB. Magnitudes are
calculated using the R USNO-B magnitudes of three
nearby stars.
[sec after GRB]
start end magnitude
86 144 R>18.1 +/- 0.3 (no detected)
150 253 R=18.5 +/- 0.3
312 370 R=18.7 +/- 0.3
376 479 R=19.1 +/- 0.4
Corresponding images can be seen at:
http://www.cesr.fr/~klotz/grb050904
After 8 minutes, the CCD camera cooler failed.
Then, images are very noisy. We will try to
obtain corresponding dark frames in the next
days to reprocess images after t_GRB+8 min.
This message can be cited.
GCN Circular 3918
Subject
GRB 050904: BAT refined analysis of partial data set
Date
2005-09-05T02:46:12Z (20 years ago)
From
Jay R. Cummings at NASA/GSFC/Swift <jayc@milkyway.gsfc.nasa.gov>
D. Palmer (LANL), L. Barbier (GSFC), S. Barthelmy (GSFC),
J. Cannizzo (GSFC-UMBC), J. Cummings (GSFC/NRC), D. Hullinger (GSFC/UMD),
E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC),
G. Sato (ISAS), M. Tashiro (Saitama U.), J. Tueller (GSFC)
on behalf of the Swift-BAT team:
Using only a small amount of the full data set from recent telemetry
downlinks, we report further analysis of Swift-BAT Trigger #153514
(Cummings, et al., GCN 3910). Due to a large backlog in data downlinking,
we have only the data from T-40 to T+120 sec. We do not expect the full
data set for at least another 2 days, so we are issuing this partial report.
The ground-analysis position is RA,Dec 13.722,14.081 {0h54m53s, 14d04'52"}
(J2000) with an uncertainty of 2.6 arcmin (radius, 90%, stat+sys).
This is 3.9 arcmin from the onboard position and 0.54 arcmin from the
IR afterglow position reported by Haislip et al. in GCN Circ. 3913.
This is a long burst with T90 greater than 120 sec. The burst started
at T+0 sec with continued emission past T+120 sec (where the downlinked
data stops).
GCN Circular 3919
Subject
GRB 050904: SOAR YJ and PROMPT Ic Observations
Date
2005-09-05T07:04:32Z (20 years ago)
From
Daniel E. Reichart at U.North Carolina <reichart@physics.unc.edu>
J. Haislip, M. Nysewander, D. Reichart, E. Cypriano, D. Maturana, S.
Pizarro, C. MacLeod, J. Kirschbrown, E. Figueredo report on behalf of the
UNC team of the FUN GRB Collaboration.
We continued observations of the afterglow (Haislip et al., GCN 3913) of
GRB 050904 (Cummings et al., GCN 3910) with SOAR and PROMPT at CTIO in YJ
and Ic, respectively, beginning 26.4 hours after the burst.
We detect the afterglow in J and refine the fading rate to be -1.00 +/-
0.12.
We also detect the afterglow in Y, which suggests that the redshift is at
the lower end of the redshift ranges of Haislip et al. (GCN 3914) and
Reichart (GCN 3915).
Furthermore, a redshift of 6 (+/- 1) appears to be consistent with the
relatively faint, unfiltered optical detections of Klotz et al. (GCN 3917)
from only minutes after the burst: Extrapolation of our J-band light curve
back to this time suggests that the afterglow was probably relatively
bright (J ~ 13 mag) redward of the Ly-alpha forest. Integration of the
light across a broad optical spectral response curve would then result in
significantly fainter magnitudes for such redshifts.
GCN Circular 3920
Subject
GRB 050904: early Swift XRT analysis results
Date
2005-09-05T10:55:21Z (20 years ago)
From
Teresa Mineo at INAF <teresa.mineo@pa.iasf.cnr.it>
T. Mineo(INAF-IASF), V. Mangano(INAF-IASF), V. La Parola(INAF-IASF),
G. Cusumano (INAF-IASF), L. Angelini (GSFC), J. Cummings (GSFC/NRC),
D. N. Burrows (PSU), F. Marshall (GSFC), P. Boyd (GSFC-UMBC)
report on behalf of the Swift XRT team:
We have analyzed the Swift XRT data from the first observation
of GRB 050904 (Cummings et al. 2005, GCN 3910) consisting
of four orbits (about 20 ks).
The refined coordinates of the X-ray afterglow are:
RA(J2000) = 0h 54m 50.6s
Dec(J2000) = +14d 05' 04.5"
with an estimated uncertainty is of 6 arcseconds radius (90%
containment).
This position is 37 arcsec from the revised BAT position given
in GCN 3918 (Palmer et al. 2005), 4.5 arcseconds from
the XRT position determined on board and 11 arcseconds
from the SOAR position (Haislip et al., GCN 3913).
The 0.2-10 keV light curve, that starts in Windowed Timing (WT) mode
169 seconds after the BAT trigger (T0), shows a fading behaviour.
Moreover two flares are clearly detected in the first orbit:
the first at T0+466 s in WT data and the second at at T0+1240 s
in Photon Counting (PC) mode data.
The light curve decay index, obtained excluding the flare
time intervals, is -2.08+/-0.03.
The remaining three orbits show irregular rate variations
likely due to other flares.
A preliminary spectral fit to WT and PC data of the first orbit,
excluding the flare time intervals, shows an evidence of spectral
evolution from hard to soft:
Time interval(s) Photon Index NHx10^20(cm^-2) Flux(erg cm^-2 s^-1)
T0+170-370 1.33+/-0.04 15+/-1 1.8x10^-9
T0+580-1760 1.70+/-0.08 5.6+/-1.0 4.6x10^-11
The Galactic absorption in the GRB direction is 5x10^20 cm^-2.
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GCN Circular 3921
Subject
GRB 050904: NIR object inside the XRT error box
Date
2005-09-05T11:38:11Z (20 years ago)
From
Paolo D'Avanzo at INAF-OAB <davanzo@merate.mi.astro.it>
P. D'Avanzo (INAF/OAB), L. A. Antonelli (INAF/OAR), S. Covino
(INAF/OAB), D. Malesani (SISSA), G. Tagliaferri, G. Chincarini
(INAF/OAB) on behalf of the MISTICI collaboration report:
We observed the field of GRB 050904 (Cummings et al., GCN 3910), in the
J band with the 3.6m TNG telescope (equipped with NICS) and with the ESO
VLT-UT1 (equipped with ISAAC). We don't detect the NIR source at the
position indicated by Haislip et al. (R.A. 00:54:51.3, Dec. 14:05:09.7,
GCN 3913, 3919) and by Klotz et al. (GCN 3917) to a limit J > 22
(5sigma). We also note that this position is ~ 6 arcsec out from the XRT
error box (Mineo et al., GCN 3920) and ~ 11" away from its center.
We detect however a single fading source inside the XRT error box, which
is likely the NIR counterpart of GRB 050904. Its coordinates are:
R.A.(J2000) = 00:54:50.8
Dec.(J2000) = +14:05:10.0
The detected source faded by 0.30 +/- 0.15 mag between the two epochs
(24.7 and 26 h after the burst, respectively). That source has a J
magnitude which is consistent with the one expected from the source
proposed by Haislip et al. with a decay slope of t^-1,
A finding chart is available at the following URL:
http://www.sissa.it/~malesani/GRB/050904/GRB050904_finder.jpg
We thank the TNG and ESO staff, in particular Marco Pedani, Poshak
Gandhi and Nancy Ageorges for carefully performing our observations and
quickly providing the data.
This message can be cited.
GCN Circular 3922
Subject
GRB 050904: Afterglow Astrometry
Date
2005-09-05T17:25:07Z (20 years ago)
From
Daniel E. Reichart at U.North Carolina <reichart@physics.unc.edu>
M. Nysewander, D. Reichart, J. Haislip report on behalf of the UNC GRB team
of the FUN GRB Collaboration:
Using a single 348 sec coadd from last night's SOAR data (Haislip et al.,
GCN 3919) and 7 USNO stars, we measure the coordinates of the afterglow to
be:
RA: 00:54:50.794
DEC: +14:05:09.42
with uncertainties of 1.6" in RA and 2.3" in DEC.
This is consistent with the astrometry of D'Avanzo et al. (GCN 3921) and
the refined coordinates of the X-ray afterglow (Mineo et al.; GCN 3920).
DR apologizes for the crudeness of our initial astrometry.
GCN Circular 3923
Subject
GRB 050904: Swift/UVOT observations
Date
2005-09-05T17:50:27Z (20 years ago)
From
Antonino Cucchiara at PSU <cucchiara@astro.psu.edu>
A. Cucchiara (PSU), J. Cummings (GSFC), S. Holland (GSFC), C. Gronwall
(PSU),
A. Blustin (MSSL), F. Marshall (GCFS), A. Smale (NASA HQ), L. Cominsky
(Sonoma State U.),
N. Gehrels (GSFC) on behalf of the Swift UVOT team
Swift/UVOT began observing the field of GRB050904 at 01:54:25 UT,
164 s after the BAT trigger (Cummings, et al., GCN 3910) in all the six
filters.
In the first 100 s V-band image (T+ 214 s), no new source is detected with
respect to the DSS down to a 3 sigma upper limit of 18.9 mag in the XRT
error
circle (GCN 3910).
At T+90 min after the trigger, in a single 900 s V-band image the upper
limit
was 20.1.
The instrument continued to collect data during all the other orbits
detecting no new source down to the following upper limits:
Filter Start_Time(UT) Stop_Time(UT) Exp(s) 3sig_limit
V 01:54 16:20 4887 20.9
B 01:56 18:12 4773 21.9
U 01:56 17:57 4686 21.6
UVW1 01:56 16:49 4292 21.1
UVM2 01:56 16:35 4684 21.4
UVW2 01:57 18:26 4331 21.4
Where Start_Time and Stop_Time are the time range over wich the summed
images
were accumulated and Exp is the total exposure time (in seconds) of the
summed image.
The magnitude upper limits are not corrected for extinction.
These non-detections are consistent with a high redshift GRB,
as reported by J. Haislip, et al. (GCN 3914 and 3919).
These magnitudes are based on preliminary zero-points, measured
in orbit, and will require refinement with further calibration.
This message can be cited.
GCN Circular 3924
Subject
GRB 050904: photometric redshift
Date
2005-09-05T18:55:57Z (20 years ago)
From
Daniele Malesani at SISSA-ISAS,Trieste,Italy <malesani@sissa.it>
L.A. Antonelli, A. Grazian (INAF/OAR), P. D'Avanzo (INAF/OABr), V. Testa
(INAF/OAR), S. Covino, G. Tagliaferri, G. Chincarini (INAF/OABr), A.
Fernandez-Soto (Univ. Valencia), D. Malesani (SISSA), F. Fiore and L.
Stella (INAF/OAR) report on behalf of the MISTICI collaboration:
"We observed the field of GRB 050904 (Cummings et al., GCN 3910; Mineo
et al., GCN 3920) with the ESO VLT-UT1, in the J, H, and K bands (with
ISAAC) and in the I band (with FORS2).
The afterglow (Haislip et al., GCN 3913; D'Avanzo et al., GCN 3921) is
detected in all filters, including the I band.
We derive for this source a photometric redshift z = 6.10 (+0.37,
-0.12; 90% confidence) by adopting a chi square minimization technique
(Fontana et al., 2000, AJ, 120, 2206). This is in agreement with the
result of Haislip et al. (GCN 3919).
This message can be cited."
GCN Circular 3925
Subject
GRB 050904: More SOAR
Date
2005-09-06T09:06:47Z (20 years ago)
From
Daniel E. Reichart at U.North Carolina <reichart@physics.unc.edu>
C. MacLeod, J. Kirschbrown, D. Reichart, E. Cypriano, P. Ugarte, A.
Alvarez, E. Figueredo report on behalf of the UNC team of the FUN GRB
Collaboration.
We continued observations of the afterglow (Haislip et al., GCN 3913) of
GRB 050904 (Cummings et al., GCN 3910) with 4.1m SOAR at CTIO in J,
beginning 52.9 hours after the burst.
The afterglow is no longer detected: J > 21.6 (2 sigma). This implies that
temporal index has steepened from -1.0 +/- 0.1 (Haislip et al., GCN 3919)
to <-2.3 over the past day, which suggests that we are now past the
jet-break time.
GCN Circular 3928
Subject
GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
Date
2005-09-06T14:27:48Z (20 years ago)
From
Jean-Luc Atteia at Lab d Astrophys.,OMP,Toulouse <atteia@ast.obs-mip.fr>
J-L. Atteia (LAT-OMP) communicates:
The high redshift of GRB 050904 suggests a possible interpretation
of the XRT observations reported in GCNC 3920 (T. Mineo et al.) as
the *prompt emission* of the burst.
- The maximum effective area of SWIFT/XRT (2 keV) corresponds to a restframe
energy of ~14 keV for a source at redshift z=6.1.
- The time of the first XRT flare is 466/(7.1) ~ 66 sec in the restframe.
- The spectral index of -1.33 is suggestive of the spectral index of
the prompt emission below the the break energy (Epeak).
All these numbers are compatible with an interpretation of the early
SWIFT/XRT observations in terms of GRB prompt emission.
In view of this possibility, further information on the duration
of GRB 050904, would be of great interest.
GCN Circular 3929
Subject
GRB 050904: BOOTES early R-band observation
Date
2005-09-06T15:34:03Z (20 years ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
M. Jelinek, A.J. Castro-Tirado, A. de Ugarte Postigo (IAA-CSIC
Granada), P. Kubanek (ASU AV CR Ondrejov), S. Vitek (CVUT
Praha), J. Gorosabel and S. Guziy (IAA-CSIC), R. Hudec (ASU
AV CR), J.M. Castro Ceron (DARK NBI Kobenhavn), P. Pata and M.
Bernas (CVUT),
report:
The BOOTES-1B 30 cm robotic telescope in Southern Spain,
has followed-up the high-redshift GRB 050904 (Cummings et
al. GCN 3910, Haislip et al. 3913, 3914, Reichart et al. 3915,
Antonelli et al. GCN 3924) starting 124s after
the onset of the burst. The upper limits derived from our
R-band filter measurements during the time interval 124s -1100s
after the event, together with the values reported by TAROT
(Klotz et al. GCN 3917) are consistent with an early decay index
of alpha = -1.2 (i.e. in agreement with the value reported
at a later epoch in the J-band by Haislip et al. GCN 3914).
This message can be quoted.
[GCN OPS NOTE(06sep05): Per author's request: "NBI" --> "DARK NBI",
added "Haislip et al. 3913, 3914, Reichart et al. 3915,",
"our R-band meaurements" --> "our R-band filter measurements",
"the value later reported" --> "the value reported at a later epoch".]
[GCN OPS NOTE(21oct05): Per author's request: in the Subject line
"detection" is changed to "observation", and in the body
"Our R-band filter measurements" is changed to "The upper limits derived
from our R-band filter measurements".]
GCN Circular 3930
Subject
GRB 050904: more VLT NIR observations
Date
2005-09-06T18:28:44Z (20 years ago)
From
Gianpiero Tagliaferri at OAB-INAF <taglia@merate.mi.astro.it>
P. D'Avanzo (INAF/OABr), L.A. Antonelli(INAF/OAR), S. Covino
(INAF/OABr), A. Grazian, V. Testa (INAF/OAR), D. Malesani (SISSA), D.
Fugazza, G. Tagliaferri (INAF/OABr), G. Chincarini (INAF/OAB & UNIMIB),
L. Stella (INAF/OAR), and A. Fernandez-Soto (Univ. Valencia) report on
behalf of the MISTICI collaboration:
We continued monitoring the afterglow (Haislip et al., GCN 3913;
D'Avanzo et al., GCN 3921) of GRB 050904 (Cummings et al., GCN 3910;
Mineo et al., GCN 3920) with the ESO VLT-UT1 (equipped with ISAAC).
Observations were performed in the J, H, and K bands, at about 50, 51
and 51.5 hours after the burst.
We still detect the afterglow in all filters. The measured magnitudes
are consistent with an unbroken decay with slope ~1 from 3 to ~50 hr
after the GRB.
We thank the ESO staff, in particular Nancy Ageorges for carefully
performing our observations and quickly providing the data.
More observations are planned.
This message can be cited.
GCN Circular 3932
Subject
GRB 050904: Keck I-band Imaging
Date
2005-09-06T18:58:03Z (20 years ago)
From
Josh Bloom at UC Berleley <jbloom@astron.berkeley.edu>
D. Perley, J. S. Bloom, M. Cooper (UCB), J. Newman (LBL), P.
Guhatakurta (UCSC), J. X. Prochaska (UCO Lick) and H.-W. Chen (MIT/U
Chicago) report on behalf of a larger group:
"We observed the field of GRB 050904 (GCN 3910) using the DEIMOS
imager on the Keck II during the early morning twilight of 05 Sept
2005 UT. The afterglow candidate reported by Haislip et al. (GCN
3913, 3922) is well-detected in the first 300-second I-band exposure,
taken at UTC=14:50 (~37.0 hours after the burst). Calibrating
against three nearby stars in SDSS, we measure a preliminary
magnitude for the afterglow of i~=22.9 +/- 0.6. This uncertainty is
dominated by the photometric calibration which we expect to improve
with further processing."
This message may be cited.
GCN Circular 3937
Subject
GRB 050904: Subaru Optical Spectroscopy
Date
2005-09-07T16:38:55Z (20 years ago)
From
Nobuyuki Kawai at Tokyo Tech <nkawai@hp.phys.titech.ac.jp>
N. Kawai (Tokyo Tech), T. Yamada (NAOJ), G. Kosugi, T. Hattori, and
K. Aoki (Subaru/NAOJ) report on behalf of Subaru GRB team:
"We observed the field of GRB 050904 (GCN 3910) with Faint Object
Camera And Spectrograph on the Subaru 8.2m telescope atop Mauna
Kea on the night of September 6, approximately 3.5 days after the
burst. We obtained spectra of the afterglow candidate (Haislip et
al. GCN 3913, 3922, D'Avanzo et al. GCN 3921).
Based on the absorption features we measure the redshift to be
z=6.29 +- 0.01, confirming the photometoric redshift reported
earlier (Haislip et al. GCN 3914, 3919, Antonelli et al. GCN 3924)."
This message may be cited.
GCN Circular 3938
Subject
GRB 050904 BAT refined analysis of complete data set
Date
2005-09-07T18:55:04Z (20 years ago)
From
Jay R. Cummings at NASA/GSFC/Swift <jayc@milkyway.gsfc.nasa.gov>
T. Sakamoto (GSFC/NRC), L. Barbier (GSFC), S. Barthelmy (GSFC),
J. Cummings (GSFC/NRC), D. Hullinger (GSFC/UMD), E. Fenimore (LANL),
N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
D. Palmer (LANL), A. Parsons (GSFC), G. Sato (ISAS), J. Tueller (GSFC)
on behalf of the Swift-BAT team:
We now have the complete BAT data for GRB 050904 (Cummings et al.,
GCN circ. 3910 and Palmer et al. GCN circ. 3918). This was a very
long, bright burst. The light curve shows 3 main peaks. There are
15-second long peaks at ~T+28 sec and ~T+56 sec, and the main peak
was from ~T+80 sec to ~T+220 sec, along with weaker peaks. Emission
in the BAT energy range continues to almost T+500 sec with a weak
peak at ~T+470 sec. T90 was 225 +/- 10 sec (estimated error including
systematics, 15-350 keV).
Fitting a simple power law from T+17 sec to T+226 sec, the photon
index is 1.34 +/- 0.06. The fluence is 5.4 +/- 0.2 x 10^6 ergs/cm^2.
The 1-second peak flux from T+27.5 sec is 0.8 +- 0.2 photons/cm^2/sec.
All errors are 90% confidence, energy range 15-150 keV.
Haislip et al. (GNC circ. 3914, 3919) reported a Ly-alpha break for
this burst corresponding to a redshift of 5.3 to 9.0. Antonelli et al.
(GCN circ. 3924) calculate a redshift of 6.1. Kawai et al. (GCN circ.
3937) report a spectrographic redshift of 6.29. With the above fluence
at this redshift (6.29), the isotropic energy equivalent is
3.8 x 10^53 ergs in the range 109 - 1094 keV in the GRB rest frame.
GCN Circular 3939
Subject
GRB050904: CrAO optical observations
Date
2005-09-07T21:38:18Z (20 years ago)
From
Vasilij Rumjantsev at CrAO <rum@crao.crimea.ua>
V.Rumyantsev (CrAO), V.Biryukov (SAI, MSU), A.Pozanenko
(IKI), M. Ibrahimov (MAO) on behalf of larger GRB follow up
collaboration report:
We observed the BAT and XRT error boxes of GRB050904
(Swift # 153514; Cummings et al., GCN 3910) with 2.6m Shain
telescope (CrAO) on September 4 between (UT) 20:39 - 21:31
in R-band filter. The OT (Haislip et al., GCN 3913, D'Avanzo
et al. GCN 3921) is not detected in our combine image.
Preliminary estimation of the limiting value of the
combined image based on USNO-A2.0 catalog is following
Mean time Exposure Filter Magnitude
(UT) s
21:04 24x120 R 23.5
Combined image can be found in http://grb.rssi.ru/GRB050904.
This message may be cited.
GCN Circular 5300
Subject
Host galaxy of GRB050904: 250 GHz upper limit with MAMBO at the IRAM 30m
Date
2006-07-12T13:31:17Z (19 years ago)
From
Fabian Walter at MPIA <walter@mpia.de>
F. Walter (MPIA Heidelberg), C. Carilli (NRAO), F. Bertoldi (AIfA Bonn),
A. Weiss (MPIfR Bonn) report:
We observed the host galaxy of GRB 050904 (GCN 3910) at redshift z=6.29
(GCN 3937), RA 00:54:50.83, Dec +14:05:10 (J2000), with the
Max-Planck-Millimeter Bolometer (MAMBO-2) array at the IRAM 30-m telescope
on 27 February 2006 and 03 March 2006, and obtained a non-detection of
S_nu(250 GHz,1.20mm) = -0.76 +/- 0.45 mJy
(1 sigma error), i.e. a 3 sigma upper flux density limit of 1.35 mJy. The
MAMBO-2 bolometer detectors cover 210-290 GHz (half power). The host
galaxy of GRB 050904 is well within our 10.7 arcsec FWHM beam.
This message may be cited.
GCN Circular 6018
Subject
GRB 050904: Second Epoch of HST/NICMOS Observations
Date
2007-01-17T19:41:48Z (18 years ago)
From
Edo Berger at Carnegie Obs <eberger@ociw.edu>
E. Berger (Carnegie Observatories) reports on behalf of a large
collaboration:
"We re-observed the position of GRB 050904 (z=6.295) with NICMOS on the
Hubble Space Telescope on 2006 July 22 UT. A total of 6 orbits (15360
sec) were obtained with the F160W (H-band) filter. Previous observations
of the burst with NICMOS on 2005 Sep 27 UT revealed a source with
F160W(AB)=26.1+/-0.2 mag (Berger et al. astro-ph/0603689), which was
interpreted as a combination of afterglow and host galaxy light. The new
observations reveal no source at the position of the burst to a 3-sigma
limit of F160W(AB)=27.2 mag. This result indicates that the host galaxy
is fainter than about 0.05 microJy, and that the light contribution from
the afterglow to the source detected in the Sep 2005 observations was
>60%, confirming the proposed jet break at t~3 days (Tagliaferri et al.
2005; Haislip et al. 2006).
A complete analysis of the new NICMOS observations, and their implications
for the afterglow and host galaxy properties, will be made available in a
revised version of astro-ph/0603689."