- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 01 Aug 05 18:28:16 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 148522, Seg_Num: 0
GRB_RA: 204.139d {+13h 36m 33s} (J2000),
204.216d {+13h 36m 52s} (current),
203.454d {+13h 33m 49s} (1950)
GRB_DEC: -21.950d {-21d 57' 00"} (J2000),
-21.978d {-21d 58' 41"} (current),
-21.695d {-21d 41' 42"} (1950)
GRB_ERROR: 4.00 [arcmin radius, statistical only]
GRB_INTEN: 3186 [cnts] Image_Peak=221 [image_cnts]
TRIGGER_DUR: 0.512 [sec]
TRIGGER_INDEX: 124 E_range: 25-100 keV
BKG_INTEN: 34816 [cnts]
BKG_TIME: 66472.00 SOD {18:27:52.00} UT
BKG_DUR: 8 [sec]
GRB_DATE: 13583 TJD; 213 DOY; 05/08/01
GRB_TIME: 66482.07 SOD {18:28:02.07} UT
GRB_PHI: -176.21 [deg]
GRB_THETA: 19.72 [deg]
SOLN_STATUS: 0x3
RATE_SIGNIF: 19.67 [sigma]
IMAGE_SIGNIF: 10.25 [sigma]
MERIT_PARAMS: +1 +0 +0 +0 +2 +9 +0 +0 -16 +1
SUN_POSTN: 132.04d {+08h 48m 09s} +17.85d {+17d 50' 55"}
SUN_DIST: 81.06 [deg]
MOON_POSTN: 93.12d {+06h 12m 30s} +28.32d {+28d 19' 28"}
MOON_DIST: 118.12 [deg]
MOON_ILLUM: 10 [%]
GAL_COORDS: 316.58, 39.72 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 210.41,-11.07 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT-BAT GRB Coordinates.
COMMENTS: This is a rate trigger.
COMMENTS: A point_source was found.
COMMENTS: This does not match any source in the on-board catalog.
COMMENTS: This does not match any source in the ground catalog.
COMMENTS: This is a GRB.
- red DSS finding chart
ps-file
- GCN/SWIFT NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 01 Aug 05 18:33:23 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 148522, Seg_Num: 0
GRB_RA: 204.139d {+13h 36m 33s} (J2000),
204.216d {+13h 36m 52s} (current),
203.454d {+13h 33m 49s} (1950)
GRB_DEC: -21.950d {-21d 57' 00"} (J2000),
-21.978d {-21d 58' 41"} (current),
-21.695d {-21d 41' 42"} (1950)
GRB_DATE: 13583 TJD; 213 DOY; 05/08/01
GRB_TIME: 66482.07 SOD {18:28:02.07} UT
TRIGGER_INDEX: 124
GRB_PHI: -176.21 [deg]
GRB_THETA: 19.72 [deg]
DELTA_TIME: 65524.00 [sec]
LC_URL: sw00148522000msb.lc
SUN_POSTN: 132.04d {+08h 48m 09s} +17.85d {+17d 50' 55"}
SUN_DIST: 81.06 [deg]
MOON_POSTN: 93.12d {+06h 12m 30s} +28.32d {+28d 19' 28"}
MOON_DIST: 118.12 [deg]
MOON_ILLUM: 10 [%]
GAL_COORDS: 316.58, 39.72 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 210.41,-11.07 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-BAT GRB Lightcurve.
COMMENTS:
COMMENTS: The next comments were copied from the BAT_POS Notice:
COMMENTS: This is a rate trigger.
COMMENTS: A point_source was found.
COMMENTS: This does not match any source in the on-board catalog.
COMMENTS: This does not match any source in the ground catalog.
COMMENTS: This is a GRB.
- GCN notice #3723
E.S. Rykoff (U Mich), S.A. Yost (U Mich), W. Rujopakarn (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 050801 (Swift trigger 148522). The first image was at
18:28:23.9 UT, 21.9 s after the burst (7.9 s after the GCN notice time).
The unfiltered images are calibrated relative to USNO A2.0. We detect a
new object, not visible in the DSS (second epoch), with coordinates:
13:36:35.4 -21:55:42.0 (J2000)
start UT mag mlim(of image)
----------------------------------
18:28:23.9 15.0 17.0
Continuing observations are in progress.
- GCN notice #3724
J.A. Kennea and D.N. Burrows (PSU)
The XRT position sent through GCN for GRB050701 is not correct due to the
XRT centroiding on a artifact in the CCD, and not the afterglow. The
current best position for this from Swift is the BAT position.
- GCN notice #3725
D.L. Band (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/NRC),
N. Gehrels (GSFC), C. Gronwall (PSU) S. Hunsberger (PSU),
J. Kennea (PSU), D. Palmer (LANL), M. Perri (ASDC)
on behalf of the Swift team:
At 18:28:02.07 UT, Swift-BAT triggered and located GRB050801 (trigger=148522).
The spacecraft slewed immediately. The BAT on-board calculated location
is RA,Dec 204.139d,-21.950d {+13h 36m 33s,-21d 57' 00"} (J2000), with an
uncertainty of 3 arcmin (radius, 90% containment, stat+sys). The BAT
light curve shows a single FRED structure with a total duration of 3 sec.
The peak count rate was ~900 counts/sec (15-350 keV), which peaks
at ~T+0.5 seconds.
The XRT began observing at 18:29:03 UT, 61 seconds after the BAT trigger.
XRT did centroid on a position, but on-ground examination of the image
revealed that the object found by the centroiding algorithm is a CCD
artifact (Kennea, GCN 3724).
Swift-UVOT began observations of GRB 050801 after the slew, however,
the UVOT dark burst image did not come down via TDRSS so no information
is available at this time. Detailed analysis will be performed
when data is available after the next Malindi pass.
Because of orbit trajectory with respect to the Malindi ground station,
we will not have access to the full data sets to produce the refined analyses
for several hours.
- GCN notice #3726
E.S. Rykoff (U Mich), S.A. Yost (U Mich), W. Rujopakarn (U Mich), H.
Swan (U Mich), K. Alatalo (Berkeley), R. Quimby (U Texas) report on
behalf of the ROTSE collaboration:
ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, is
observing the optical counterpart to GRB 050801 (Swift trigger 148522,
Band et al, GCN 3725). The early afterglow reported in GCN 3723 is
characterized by a broken power-law, which does not decay significantly
from t+21s to t+200s, followed by a decline with a power law index of
~-1.1. Our preliminary photometry, relative to the USNO A2.0 catalog,
also shows some possible sub-structure to the lightcurve.
tstart-tburst exptime mag
---------------------------------
21.8 5.0 14.99+/-0.06
203.0 20.0 15.01+/-0.03
1590.3 60.0 17.29+/-0.15
- GCN notice #3728
B. Monard (Bronberg Observatory) reports on behalf
of the AAVSO International High Energy Network:
We observed the afterglow (Rykoff et. al., GCN 3723) for
the Swift burst GRB 050801 (Band et al., GCN 3725), using
the 30cm telescope plus ST-7XME CCD camera of Bronberg
Observatory. Using the UCAC2 star at 13:36:40.87
-21:55:58.6 as having a derived Rc magnitude of 14.5,
we obtain the following photometry:
UT / CR mag
19:03.0 17.5
19:05.5 17.7
19:08.0 17.9
19:10.5 18.1
19:14.5 18.4:
Uncertainty in timing : 30sec absolute, 10 sec relative
Uncertainty in magnitude : 0.3 in accuracy, 0.1 in precision
No further observations are planned.
- GCN notice #3729
B. E. Cobb and C. D. Bailyn (Yale), part of the larger SMARTS
consortium, report:
Using the ANDICAM instrument on the 1.3m telescope at CTIO, we
obtained optical/IR imaging of the error region of GRB 050801
(GCN 3725, Band et al.) with a mid-exposure time of
2005-08-02 00:01 UT, which is ~5.5 hours post-burst.
Total summed exposure times amounted to 15 minutes in I and V and
12 minutes in J and K.
The afterglow of GRB 050801 (GCN 3723, Rykoff et al.) is
detected in our optical images. However, the afterglow
is not significantly detected in our IR images.
Preliminary photometry, obtained in comparison with
USNO-B1.0 stars, indicates the magnitude of the
afterglow at ~5.5 hours post-burst to be I = 20.2+/-0.2.
The afterglow is not bright enough in the individual optical
frames to significantly measure its decay over our ~40 minutes
of observations.
In comparison with 2MASS stars, the limiting IR magnitudes
are J > 18.6+/-0.2 and K > 17.0+/-0.2.
- GCN notice #3730
T. Sakamoto (GSFC/NRC), C. Markwardt (GSFC/UMD),
L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/NRC),
E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD),
H. Krimm (GSFC/USRA), F. Marshall (GSFC),
D. Palmer (LANL), A. Parsons (GSFC), G. Sato (ISAS),
T. Takahashi (ISAS), J. Tueller (GSFC), on behalf of the Swift-BAT team:
At 18:28:02 UT Swift-BAT detected GRB 050801 (trigger=148522)
(GCN Circ 3725, Band, et al.). The refined BAT ground position
is (RA,Dec) = 204.140, -21.937 [deg; J2000] {13h36m33.6s,-21d59'14.7"}
+-3 arcmin, (95% containment). The partial coding was 99 %.
The light curve shows two peaks which are separated by about 3 seconds.
The second peak is weaker and has a softer spectrum than the first peak.
T90 (15-350 keV) is (20 +- 3) seconds (estimated error including
systematics).
The power law index of the time-averaged spectrum is 2.0 +- 0.2.
The fluence in the 15-350 keV band is (4.4 +- 1.0) x 10^-7 erg/cm2.
The 1-s peak photon flux measured from T0+0.27 second in the 15-350 keV
band is (1.7 +- 0.2) ph/cm2/s. All the quoted errors are at the 90%
confidence level.
- GCN notice #3731
M. Perri, M. Capalbi, P. Giommi (ASDC), J. Kennea, D.N. Burrows, P.
Meszaros
(PSU), K. Hinshaw (GSFC-SPSYS) report on behalf of the Swift XRT team:
We have analyzed the Swift XRT data from the first orbit observation
of GRB 050801 (Band et al., GCN 3725). A fading, previously uncatalogued,
point source at the following coordinates is detected in the field:
RA(J2000) = 13h 36m 36.0s
Dec(J2000) = -21d 55' 42"
This position is 83 arcseconds from the BAT position given in GCN
3725 (Band et al.) and 8.5 arcsec from the ROTSE-III position reported
in GCN 3723 (Rykoff et al.). The source is close to a bad column of the
CCD
and we estimate an uncertainty of 10 arcseconds radius in the derived
position.
Data in Photon Counting (PC) mode starts at 18:29:31 UT, 89 seconds from
the BAT trigger. The 0.3-10 keV afterglow light curve shows a flat slope
from T+89s to T+300s and then declines following a power law with decay
index
alpha=-1.3+/-0.3 up to T+990s, when first orbits ends.
A preliminary spectral fit in the 0.3-10 keV energy band to the first
orbit
gives a spectral power law photon index of 1.8+/-0.3 with Nh=5.7E20 cm^-2.
In the time range 89-990 seconds from trigger the average unabsorbed
0.5-10 keV flux is 2.6E-11 erg cm^-2 s^-1.
- GCN notice #3733
A. J. Blustin (UCL-MSSL), D. Band (GSFC), S. Hunsberger (PSU),
C. Gronwall (PSU), M. Carter (UCL-MSSL), P. Smith (UCL-MSSL)
on behalf of the Swift/UVOT team report:
The Swift/UVOT began observing the afterglow of GRB050801 at
2005-08-01T18:32:00, 238 s after the BAT trigger (Band et al.,
GCN 3725). The afterglow was detected in all six optical and
UV filters at a position (J2000, corrected to the DSS
coordinates) of:
RA 13:36:35 (+/- 1 arcsec)
DEC -21:55:41 (+/- 1 arcsec)
We give two lightcurve points for each filter in the table
below so that decay slopes may be determined.
Filter T_mid Exp Magnitude
V 244 9.78 15.9 +/- 0.2
V 919 9.77 17.9 +/- 0.8
B 215 9.78 16.0 +/- 0.1
B 890 9.78 18.0 +/- 0.4
U 201 9.78 15.20 +/- 0.09
U 961 9.76 17.2 +/- 0.3
UVW1 187 9.78 15.5 +/- 0.1
UVW1 11316 899.77 20.1 +/- 0.3
UVM2 173 9.78 16.0 +/- 0.2
UVM2 6590 337.06 20.6 +/- 0.9
UVW2 230 9.78 17.4 +/- 0.4
UVW2 4524 670.56 21.0 +/- 0.4
Where Tmid is the midpoint of the exposure post-trigger in seconds.
The magnitudes are based on preliminary zero points, measured in
orbit, and will require refinement with further calibration. All
magnitudes are uncorrected for Galactic reddening.
- GCN notice #3736
GRB050801.769: Optical photometry and decay index
J. P. U. Fynbo, B. L. Jensen, J. Hjorth, K. G. Woller, D. Watson
(Niels Bohr Institute), P. Fouque (Obs-MiP, Toulouse), M. I. Andersen
(Potsdam, AIP) report on behalf of the DARK Cosmology Centre:
"We obtained BVR-band imaging of the XRT error circle of
GRB050801.769 (Band et al. GCN#3725, Perri et al. GCN#3731) with
the Danish 1.5m (La Silla) on Aug. 2.0 UT (approx. 6hr after the
burst). We detect the optical afterglow candidate source reported
by Rykoff et al. (GCN#3726), with position (RA, Dec)(J2000.0)
13:36:35.363, -21:55:42.03
Based on a preliminary std. star calibration, we obtain the
following photometry of the afterglow candidate:
Date (UT): Filter: Exptime: Mag.
Aug 1.997 B 600s 22.36+-0.05
Aug 2.012 V 600s 21.03+-0.05
Aug 1.989 R 600s 20.75+-0.04
Aug 2.005 R 600s 20.87+-0.04
Aug 2.020 R 600s 20.94+-0.05
(in this calibration, we obtain B=20.95, V=19.74, R=19.63 for the star
at: (RA, Dec) = (13:36:33.657, -21:55:29.55)).
Fitting a power-law to our three R-band data points gives a lightcurve,
which intersects the R=17.29 ROTSE-III (Rykoff et al. GCN#3726) data
point at t-t0=1590s, to within the errors of that data point.
Including the ROTSE-III data point in the fit, we find an R-band decay
slope of -1.29 +-0.05.
A finding chart of the field is shown at:
http://www.astro.ku.dk/~brian_j/grb/grb050801.769
- GCN notice #3743
GRB050801.769: Unchanged decay slope
J. P. U. Fynbo, B. L. Jensen, J. Hjorth, K. G. Woller, D. Watson,
J. Sollerman (Niels Bohr Institute), P. Fouque (Obs-MiP, Toulouse),
M. I. Andersen (Potsdam, AIP) report on behalf of the DARK Cosmology
Centre:
"We have obtained additional DK-1.5m R-band imaging (Aug 3.0 UT) of the
optical afterglow (Rykoff et al. GCN#3726) of GRB050801.769 (Band et
al. GCN#3725).
Extending the fit from Fynbo et al. (GCN#3726) yields a smooth
well-fitting power-law from t-t0=0.44h to 29.5h, with an R-band decay
slope of -1.31 +- 0.04.
The lightcurve is shown at:
http://www.astro.ku.dk/~brian_j/grb/grb050801.769
Left: Finding chart for GRB 050801.769.
R:3x600s image taken at Aug 2.0, 2005 UT, (FWHM~1.2").
The WCS-solution is calibrated to 12 nearby 2MASS-stars, with an uncertainity of +-0.1".
Right: R-band lightcurve for GRB 050801.769
The first measurement (open circle at t=0.02d) is the last ROTSE-IIIc detection
reported by Rykoff et al. (GCN#3726).
The three measurements at t=0.2d (closed circles) are from Fynbo et al. (GCN#3735),
the measurement at t=1.2d (closed circle) is from Fynbo et al. (GCN#3743).
- GCN notice #3762
P. B. Cameron (Caltech) reports on behalf of the Caltech-NRAO-Carnegie
collaboration:
"We observed the field of GRB050801 (GCN 3725) with the Very Large Array
at 8.5 GHz beginning August 2.06 UT. No radio source is detected at the
position of the optical source (GCN 3723) with a 2-sigma upper limit of
60 uJy.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
- astro-ph/0601350 from 16 Jan 2006
Rykoff: The Anomalous Early Afterglow of GRB 050801
The ROTSE-IIIc telescope at the H.E.S.S. site, Namibia, obtained the earliest
detection of optical emission from a Gamma-Ray Burst (GRB), beginning only 21.8
s from the onset of Swift GRB 050801. The optical lightcurve does not fade or
brighten significantly over the first ~250 s, after which there is an
achromatic break and the lightcurve declines in typical power-law fashion. The
Swift/XRT also obtained early observations starting at 69 s after the burst
onset. The X-ray lightcurve shows the same features as the optical lightcurve.
These correlated variations in the early optical and X-ray emission imply a
common origin in space and time. This behavior is difficult to reconcile with
the standard models of early afterglow emission.
- astro-ph/0703447 from 16 Mar 2007
Pasquale: Early afterglow detection in the Swift observations of GRB 050801
We present results of Swift optical, UV and X-ray observations of the
afterglow of GRB 050801. The source is visible over the full optical, UV and
X-ray energy range of the Swift UVOT and XRT instruments.Both optical and X-ray
lightcurves exhibit a broad plateau (\Delta t/t ~ 1) during the first few
hundred seconds after the gamma-ray event. We investigate the multiwavelength
spectral and timing properties of the afterglow, and we suggest that the
behaviour at early times is compatible with an energy injection by a newly born
magnetar with a period of a few tenths of a millisecond, which keeps the
forward shock refreshed over this short interval by irradiation. Reverse shock
emission is not observed. Its suppression might be due to GRB ejecta being
permeated by high magnetic fields, as expected for outflows powered by a
magnetar.Finally, the multiwavelength study allows a determination of the burst
redshift, z=1.56.
- ApJ Suppl. 185 (2009) 526 from 2009 November 30
Redshift is z=1.38
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