- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Thu 19 Oct 06 04:19:45 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 234516, Seg_Num: 0
GRB_RA: 91.617d {+06h 06m 28s} (J2000),
91.725d {+06h 06m 54s} (current),
90.818d {+06h 03m 16s} (1950)
GRB_DEC: +29.573d {+29d 34' 21"} (J2000),
+29.571d {+29d 34' 17"} (current),
+29.578d {+29d 34' 42"} (1950)
GRB_ERROR: 3.00 [arcmin radius, statistical only]
GRB_INTEN: 15996 [cnts] Image_Peak=192 [image_cnts]
TRIGGER_DUR: 4.096 [sec]
TRIGGER_INDEX: 299 E_range: 25-100 keV
BKG_INTEN: 140725 [cnts]
BKG_TIME: 15486.48 SOD {04:18:06.48} UT
BKG_DUR: 40 [sec]
GRB_DATE: 14027 TJD; 292 DOY; 06/10/19
GRB_TIME: 15546.96 SOD {04:19:06.96} UT
GRB_PHI: 70.44 [deg]
GRB_THETA: 40.12 [deg]
SOLN_STATUS: 0x3
RATE_SIGNIF: 11.91 [sigma]
IMAGE_SIGNIF: 7.37 [sigma]
MERIT_PARAMS: +1 +0 +0 +3 +2 +3 +0 +1 +40 +1
SUN_POSTN: 203.77d {+13h 35m 05s} -9.91d {-09d 54' 43"}
SUN_DIST: 113.99 [deg] Sun_angle= 7.5 [hr] (West of Sun)
MOON_POSTN: 173.43d {+11h 33m 42s} +3.16d {+03d 09' 41"}
MOON_DIST: 81.22 [deg]
MOON_ILLUM: 8 [%]
GAL_COORDS: 181.74, 4.25 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 91.41, 6.14 [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.
COMMENTS: This trigger occurred at longitude,latitude = 114.05,3.54 [deg].
- red DSS finding chart
ps-file
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Thu 19 Oct 06 04:22:48 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 234516, Seg_Num: 0
GRB_RA: 91.617d {+06h 06m 28s} (J2000),
91.725d {+06h 06m 54s} (current),
90.818d {+06h 03m 16s} (1950)
GRB_DEC: +29.573d {+29d 34' 21"} (J2000),
+29.571d {+29d 34' 17"} (current),
+29.578d {+29d 34' 42"} (1950)
GRB_DATE: 14027 TJD; 292 DOY; 06/10/19
GRB_TIME: 15546.96 SOD {04:19:06.96} UT
TRIGGER_INDEX: 299
GRB_PHI: 70.44 [deg]
GRB_THETA: 40.12 [deg]
DELTA_TIME: 32.00 [sec]
TRIGGER_DUR: 4.096 [sec]
SOLN_STATUS: 0x3
RATE_SIGNIF: 11.91 [sigma]
IMAGE_SIGNIF: 7.37 [sigma]
LC_URL: sw00234516000msb.lc
SUN_POSTN: 203.77d {+13h 35m 06s} -9.91d {-09d 54' 45"}
SUN_DIST: 113.99 [deg] Sun_angle= 7.5 [hr] (West of Sun)
MOON_POSTN: 173.45d {+11h 33m 47s} +3.15d {+03d 08' 58"}
MOON_DIST: 81.25 [deg]
MOON_ILLUM: 8 [%]
GAL_COORDS: 181.74, 4.25 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 91.41, 6.14 [deg] ecliptic lon,lat of the burst (or transient)
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.
COMMENTS: This trigger occurred at longitude,latitude = 114.05,3.54 [deg].
- GCN Circular #5728
C. Guidorzi (Univ Bicocca&INAF-OAB), F. E. Marshall (NASA/GSFC),
K. M. McLean (LANL/UTD), D. M. Palmer (LANL),
P. Romano (Univ. Bicocca & INAF-OAB), M. Stamatikos (NASA/ORAU) and
D. E. Vanden Berk (PSU) report on behalf of the Swift Team:
At 04:19:06 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 061019 (trigger=234516). The BAT on-board calculated
location is RA,Dec 91.617, +29.573 {06h 06m 28s, +29d 34' 21"} (J2000)
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a
multiple-peaked light curve with a duration of at least 20 sec.
The peak count rate was ~1200 counts/sec (15-350 keV), at ~2 sec
after the trigger.
Because of an Earth limb constraint, the spacecraft will not be
able to slew to the BAT position until T+45 minutes, and so there
are no immediate XRT or UVOT data products to analyze.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Thu 19 Oct 06 05:05:53 UT
NOTICE_TYPE: Swift-XRT Nack-Position
TRIGGER_NUM: 234516, Seg_Num: 0
POINT_RA: 91.648d {+06h 06m 36s} (J2000)
POINT_DEC: +29.573d {+29d 34' 25"} (J2000)
IMG_START_DATE: 14027 TJD; 292 DOY; 06/10/19
IMG_START_TIME: 18339.60 SOD {05:05:39.60} UT, 2792.6 [sec] since BAT Trigger Time
COUNTS: 3 Min_needed= 20
STD_DEV: 0.00 Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER: 1 Max_iter_allowed= 4
ERROR_CODE: 1
COMMENTS: SWIFT-XRT Nack Position.
COMMENTS: No source found in the image.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Thu 19 Oct 06 05:43:03 UT
NOTICE_TYPE: Swift-XRT Position
TRIGGER_NUM: 234516, Seg_Num: 0
GRB_RA: 91.6294d {+06h 06m 31.0s} (J2000),
91.7380d {+06h 06m 57.1s} (current),
90.8309d {+06h 03m 19.4s} (1950)
GRB_DEC: +29.5695d {+29d 34' 10.2"} (J2000),
+29.5684d {+29d 34' 06.1"} (current),
+29.5755d {+29d 34' 31.7"} (1950)
GRB_ERROR: 7.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN: 1.40e-11 [erg/cm2/sec]
GRB_SIGNIF: 4.30 [sigma]
IMG_START_DATE: 14027 TJD; 292 DOY; 06/10/19
IMG_START_TIME: 18343.79 SOD {05:05:43.79} UT, 2796.8 [sec] since BAT Trigger Time
TAM[0-3]: 327.61 237.19 261.35 242.66
AMPLIFIER: 2
WAVEFORM: 134
SUN_POSTN: 203.83d {+13h 35m 18s} -9.93d {-09d 55' 58"}
SUN_DIST: 114.03 [deg] Sun_angle= 7.5 [hr] (West of Sun)
MOON_POSTN: 174.03d {+11h 36m 07s} +2.84d {+02d 50' 07"}
MOON_DIST: 81.90 [deg]
MOON_ILLUM: 8 [%]
GAL_COORDS: 181.74, 4.26 [deg] galactic lon,lat of the burst
ECL_COORDS: 91.43, 6.14 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
COMMENTS: TAM values are not valid.
COMMENTS: These values refer to 45 min after BAT trigger.
- GCN Circular #5729
C. Guidorzi, P. Romano (Univ Bicocca&INAF-OAB) report on behalf of the
Swift/XRT team:
The Swift XRT began observing GRB 061019 (trigger #234516, Guidorzi et
al., GCN Circ. 5728) at 05:05:46.60 UT, 46.7 minutes after the BAT trigger.
Analysis of the initial TDRSS downliked data reveals a faint and
uncataloged source at the following coordinates:
RA(J2000) = 06h06m31.05s
Dec(J2000) = +29:34:10.17
with an estimated uncertainty of 8.2 arcseconds (90% containment).
This position lies 41 arcseconds from the center of the BAT error circle
reported in GCN Circ 5728.
Due to the small number of counts, we are unable to determine whether
the source is decaying at this time. However, observations are being
performed and will become available after the Malindi gap
(which ends at 07:21 UT).
This circular is an official product of the Swift XRT Team.
- GCN Circular #5730
S. Covino, E. Molinari, G. Chincarini, F.M. Zerbi, V. Testa, G.
Tosti, F. Vitali, P. Conconi, L.A. Antonelli, G. Cutispoto, G.
Malaspina, L. Nicastro, E. Palazzi, E. Meurs, and P. Goldoni report
on behalf of the REM/ROSS team:
We imaged the field of GRB 061019 (Guidorzi et al. GCN 5728, 5729)
with the robotic 60-cm REM telescope located at La Silla (Chile). A
first set of observations was performed automatically in the optical
and near infrared (V,R,I and z', J, H, K bands) starting on October
19 5:23 UT.
A preliminary analysis reveals an uncatalogued source of K ~ 14.5 at
RA,DEC = (06:06:30.85, +29:34:13.3).
At present we cannot say whether this source is fading or not.
Further observations are in progress.
This message may be cited.
- GCN Circular #5731
Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report:
We imaged the field of GRB 061019 detected by SWIFT
(trigger 234516) with the TAROT robotic telescope (D=25cm)
located at the La Silla observatory, Chile.
The observations started 43.5s after the GRB trigger
(5.3s after the notice). The elevation of the field increased from
from 1 degrees above horizon and weather conditions
were good. Unfortunately, the local horizon does not
allow to obtain sky images before 902s after the trigger
(when the source was higher than 4 deg. elevation).
No OT was detected at the position of XRT (Guidorzi & Romano,
GCNC 5729) nor at the position of REM (Covino et al. GCNC 5730).
The date of trigger : t0 = 2006-10-19T04:19:06.816
The first image is 90.0s exposure:
t0+902s to t0+992s : R > 14.8
We co-added a series of exposures:
t0+904s to t0+1382s : R > 15.8
Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.
N.B. Galactic coordinates are lon=181.7352 lat= +4.2508
and the galactic extinction in R band is 3.1 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.
N.B. Sky was cloudy at the TAROT Calern observatory.
This message may be cited.
- GCN Circular #5732
T. Sakamoto (GSFC/ORAU), L. Barbier (GSFC), S. D. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
C. Guidorzi (Univ Bicocca&INAF-OAB), D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC),
G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC)
on behalf of the Swift-BAT team:
Using the data set from T-240 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 061019 (trigger #234516)
(Guidorzi, et al., GCN Circ. 5728). The BAT ground-calculated position
(using the second peak only) is RA,Dec = 91.631, 29.545 deg
{6h 6m 31.5s, 29d 32' 43.3"} (J2000) +- 1.8 arcmin, (radius, sys+stat,
90% containment). The partial coding was 5%.
The mask-weighted lightcurve shows two peaks. The first (pre-trigger peak),
started ~T-170 sec and lasted for ~20 sec. The second peak (the triggering peak)
rises a little faster than decaying. It starts at ~T-4 sec, peaks at T+4 sec,
and ends at ~T+30 sec. The second peak is a little brighter than the first.
There is a hint of on-going emission between the two peaks. Because of a s/c slew
terminating the data collection, we can not say if there is any further emission
past T+60 sec. T90 is 191 +- 3 sec (estimated error including systematics).
For the second (triggering peak), the time-averaged spectrum from
T-4.0 to T+27.7 is best fit by a simple power-law model. The power law index
of the time-averaged spectrum is 1.85 +- 0.26. The fluence in the 15-150 keV
band is 1.7 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured
from T+3.57 sec in the 15-150 keV band is 2.2 +- 0.6 ph/cm2/sec.
For the first (pre-trigger peak), the time-averaged spectrum from
T-175 to T-150 sec is best fit by a simple power-law model. The power law index
of the time-averaged spectrum is 2.17 +- 0.40. The fluence in the 15-150 keV
band is 7.3 +- 1.9 x 10^-7 erg/cm2.
The total fluence (both peaks) is 2.4 +- 0.3 x 10^-6 srg/cm2.
All the quoted errors for both fits are at the 90% confidence level.
- GCN Circular #5733
C. Guidorzi, P. Romano (Univ Bicocca & INAF-OAB), A. Moretti (INAF-OAB)
on behalf of the Swift-XRT team:
We have analysed the first 3 orbits of Swift-XRT data of GRB 061019
(Guidorzi et al., GCN Circ. 5728). The data set consists of 6.5 ks in
Photon Counting (PC) mode.
We derived an XRT refined position of:
RA(J2000) = 06h 06m 30.73s
Dec(J2000) = 29d 34' 10.5''
with an estimated error radius of 6.7 arcsec (90% containment, including
boresight uncertainties). This lies 4.2 arcsec from the preliminary XRT
position (Guidorzi et al., GCN Circ. 5729) and 88 arcsec from the
ground-refined BAT position (Sakamoto et al., GCN Circ. 5732).
The XRT refined position is still within the BAT error circle.
The K-band candidate reported by Covino et al. (GCN Circ. 5730) lies
within the refined XRT error circle, 3.2 arcsec from our new position.
The X-ray lightcurve shows an initial slope of 0.7 +/- 0.4, with possible
break around 10^4 s after the burst to an almost flat decay.
Alternatively, it can be fit with a single power law with slope 0.56 +-
0.10.
Further data will help clarify this ambiguity.
The time-averaged spectrum (from T+2.8 ks to T+17 ks) can be fit with an
absorbed power-law with a photon index of 2.1 +/- 0.3 (90%) and an
absorption
column of (9 +/- 2)e21 cm^-2 (90%), significantly in excess of the Galactic
value in the direction of the burst (4.8e21 cm^-2).
The mean observed (unabsorbed) flux in the 0.3-10 keV energy band is
4.2e-12 (9.2e-12) erg cm^-2 s^-1.
Assuming the single power-law decay, the count rate at T+24 h
is predicted to be 1.6e-2 cts s^-1, corresponding to an unabsorbed
0.3-10 keV flux of 2.2e-12 erg cm^-2 s^-1.
This circular is an official product of the Swift-XRT team.
- GCN Circular #5734
B. E. Cobb (Yale), part of the larger SMARTS consortium, reports:
Using the ANDICAM instrument on the 1.3m telescope at CTIO, we
obtained optical/IR imaging of the error region of GRB 061019
(GCN 5728, Guidorzi et al.) with a mid-exposure time of
2006-10-19 07:29 UT, which is ~3.2 hours post-burst.
Total summed exposure times amounted to 15 minutes in I and V and
12 minutes in J and K.
Within the error region of the X-ray afterglow detection
(GCN 5729, Guidorzi et al.), we detect the source reported
by Covino et al. (GCN 5730), in the I, J and K bands.
The source is not detected in V, to a limiting magnitude
of ~22. The preliminary magnitudes of this source
(calibrated against several 2MASS stars in IR and USNO-B1.0
stars in the optical) are:
time post-
burst (hrs) I J K
------------------------------------------------------------
3.2 20.2 +/- 0.3 17.9 +/- 0.1 15.4 +/- 0.1
(not corrected for the expected high Galactic extinction)
This indicates that the source has faded by ~1 magnitude
since the Covino et al. K-band observations, taken
~1.1 hours post-burst. This source is therefore confirmed to
be the afterglow of GRB 061019, wth a decay rate of alpha ~ -0.8.
- GCN Circular #5735
F.E. Marshall (NASA/GSFC) and C. Guidorzi (Univ Bicocca&INAF-OAB)
report on behalf of the Swift-UVOT team:
The Swift UVOT began observing the GRB 061019 field (trigger 234516) 2790
seconds after the BAT trigger (Guidorzi et al. GCN Circ. 5728). Exposures
were taken with the V, B, U, W1, M2, and W2 filters. No new source was detected
within the XRT error circle (Guidorzi et al. GCN Circ. 5733).
The effects of a nearby bright star complicate the analysis, but
we estimate a 3-sigma upper limit of ~19th magnitude at the position
of the optical afterglow (Covino et al. GCN Circ. 5730; Cobb et al. GCN Circ. 5734)
for the initial exposure with the V filter.
- GCN Circular #5737
P. Romano, C. Guidorzi (Univ Bicocca & INAF-OAB), A. Moretti (INAF-OAB),
K. L. Page, (U. Leicester) on behalf of the Swift-XRT team
Analysis of the Swift XRT observation of GRB 061019 in Photon Counting
(PC) mode has revealed in the first three orbits a diffuse X-ray halo
centered around the afterglow location.
The halo has the form of a complete ring which increases in radius through
the observation and reached the distance of >=100 arcsec during the first
~17ks after the trigger (T0).
We can exclude it is due to instrumental effects.
During the observation, which started ~2800 seconds after the burst
trigger time, the observed halo follows the expected behaviour
of a "light-echo" as X-rays are scattered by dust in our Galaxy.
GRB 061019 is in the direction (Galactic) l = 181.74, b = 4.26 degrees, in
which the density of the interstellar medium is quite high as testified by
both the neutral Hydrogen column density nH=4.8E21 cm-2 and the optical
extinction E(B-V)=1.144 (A_B=4.939).
- GCN Circular #5738
A. C. Updike, K. V. Garimella, and D. H. Hartmann (Clemson University)
report on behalf of the Clemson GRB Follow-Up Team:
We imaged the field of GRB 061019 (GCN 5728) 4 hours and 52 minutes
after Swift Trigger 234516 (Guidorzi et al.) with the SARA 0.9m at Kitt
Peak under good weather conditions. We obtained 20 180-second exposures
in the R band. We find no fading OT candidate down to a limiting
magnitude of R = 20.5 +/- 0.3 mag (based on calibration of 10 field
sources from USNO A2.0).
The Clemson Unversity GRB Response Site may be found at:
http://people.clemson.edu/~kgarime/burst/index.php
The SARA Homepage can be found at:
http://saraobservatory.org
This message may be cited.
- GCN Report 8.1
GCN_Report 8.1 has been posted:
http://gcn.gsfc.nasa.gov/reports/report_8_1.pdf
by C.Guidorzi et al.
titled: "Swift Observations of GRB 061019"
- GCN Circular #5739
E. Klunko (ISTP), A. Pozanenko (IKI) on behalf of larger GRB follow up
collaboration report:
We observed the error-box error box of GRB061019 (Guidorzi et al., GCN 5728)
with 1.5m telescope of Sayan Observatory (Mondy) in R-bands on Oct.19
between (UT) 18:11 and 19:00. In a combined image (30 x 100 s) within
refined XRT error circle (Guidorzi et al., GCN 5733) we do not found any
object down to limiting magnitude R~19.0 (3 sigma). The limiting magnitude
is based on USNO A2.0 catalog.
This message may be cited.
- GCN Circular #5740
V. Rumyantsev (CrAO), A. Pozanenko (IKI) on behalf of larger GRB follow up
collaboration report:
We observed error box of GRB061019 (Guidorzi et al., GCN 5728) with Shajn
2.6m telescope of CrAO. A set of R-exposures was taken on October 20,
between (UT) 00:07 - 01:47. Near refined XRT error circle (Guidorzi et
al., GCN 5733) we found a single object in coordinates (J2000) RA=06 06
30.17 Dec=+29 34 10.50, uncertainties in both coordinates are about 1". A
photometry of the object in a combined image (86x60 s) against USNO A2.0
star (RA=06 06 31.89 Dec=+29 34 58.20 R=18.5) is 22.22+/-0.05, and 3 sigma
limiting magnitude is R=24.5. At present time it is not clear whether the
object is connected with afterglow (Covino et al., GCN 5730; Cobb et al.,
GCN 5734).
This message may be cited.
- GCN Circular #5742
A. C. Updike (Clemson), P. A. Milne (Steward Observatory), G. G. Williams
(MMTO), D. H. Hartmann (Clemson), and K. V. Garimella (Clemson) on behalf
of the Super-LOTIS Collaboration, report:
The robotic 0.6-m Super-LOTIS telescope began observing the error box of
GRB 061019 (Swift Trigger 234516, Guidorzi et al. GCN 5728) at
04:19:06 UT, 3 hours and 4 minutes after the trigger. Our initial
observations were 14x60 exposures in the R band. The observations began
at a high airmass of 1.73.
We do not detect any new source within the XRT error box in our earliest
exposure or in the sum of the R band images to the following 3-sigma
limiting magnitudes determined from nearby USNO-A2.0 stars:
t_start (UT) exp (s) Limit
-------------------------------------------------
07:23:00 14x60 R > 21.2
The source was not detected in subsequent R,V and I band images of
similar total exposure.
- GCN Circular #5756
T. Ishimura, Y. Yatsu, T. Shimokawabe, N. Vasquez, and N. Kawai (Tokyo
Tech) report on behalf of the MITSuME collaboration:
We observed the error box of GRB061019 (Guidorzi et al., GCN 5728)
with the 50cm MITSuME Telescope at Akeno, Japan on Oct 19 between
13:43:36 and 16:05:31 UT, starting 9.4 hours after the trigger.
In the combined images (30s x 165) of I and R bands, we do not detect
any new source within the XRT error box. The 3-sigma limiting
magnitudes based on USNO-B1.0 (I-band) and NOMAD (R-band) stars are
I=18.7 and R=19.5 respectively.
- GCN Circular #5786
V. Rumyantsev (CrAO), A. Pozanenko (IKI) on behalf of larger GRB follow up
collaboration report:
We observed error box of GRB061019 (Guidorzi et al., GCN 5728) with Shajn
2.6m telescope of CrAO on Oct. 20 in R-band and Oct. 21 in integral light.
After refined analysis of Oct. 20 observation (Rumyantsev et al., GCN
5740) two objects were identified within/near XRT error circle (Guidorzi et
al., GCN 5733): the object 'a' mentioned in GCN5740, and the object 'b'.
(Finding chart is available in
http://grb.rssi.ru/GRB061019/GRB061019R_ZTSh.gif).
While the object 'a' is present in both epochs, the object 'b' marginally
detected in the first epoch is absent on the combined image of second epoch
(the Oct.21 observation).
Astrometry of source 'b' is following:
RA(J2000)=06 06 30.93 Dec(J2000)=+29 34 12.5 with uncertainties in both
coordinate 0.5". The position of source 'b' coincides within 2-sigma error
bars with the optical afterglow (Covino et al., GCN 5730). We suggest that
the source 'b' is connected with the afterglow. The formal photometry of the
source 'b' based on USNO A2.0 (R) stars:
Date (UT), Filter, R_mag, R_Lim (3sigma)
Oct.20 00:07 - 01:47 R 24.86 +0.76/-0.44 24.4
Oct.21 00:48 - 01:28 None - 24.5
This message may be cited.
- 0707.2343from 16 Jul 2007
Vianello: Dust-scattered X-ray halos around two Swift gamma-ray bursts: GRB 061019 and GRB 070129
Abstract: Two new X-ray expanding rings were detected by the Swift XRT instrument
during early follow-up observations of GRB 061019 and GRB 070129, increasing to
5 the number of dust scattering X-ray halos observed around GRBs. Although
these two halos were particularly faint, a sensitive analysis can be performed
optimizing for the Swift satellite the method developed by Tiengo & Mereghetti
(2006) to analyze dust scattering rings observed with XMM-Newton. In the case
of GRB 061019, a known giant molecular cloud is identified as the responsible
for the scattering process and its distance is accurately measured (d=940 +/-
40 pc) through the dynamics of the expanding ring. In the second case, XRT
observed both the main peak of the prompt emission of GRB 070129 and the
scattering halo, but the small number of detected halo photons prevents us to
discriminate between different dust models.
Previous IAU Circulars 
