- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 06 Jun 23 01:01:02 UT
NOTICE_TYPE: Swift-XRT Nack-Position
TRIGGER_NUM: 1173731, Seg_Num: 0
POINT_RA: 166.784d {+11h 07m 08s} (J2000)
POINT_DEC: +36.505d {+36d 30' 17"} (J2000)
IMG_START_DATE: 20101 TJD; 157 DOY; 23/06/06
IMG_START_TIME: 3655.67 SOD {01:00:55.67} UT
COUNTS: 2 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.
- red DSS finding chart
ps-file
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 06 Jun 23 01:05:09 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 1173731, Seg_Num: 0
POINT_RA: 166.783d {+11h 07m 08s} (J2000)
POINT_DEC: +36.504d {+36d 30' 16"} (J2000)
POINT_ROLL: 290.161d
IMG_START_DATE: 20101 TJD; 157 DOY; 23/06/06
IMG_START_TIME: 3661.10 SOD {01:01:01.10} UT
FILTER: 10, White
BKG_MEAN: 6.198
N_STARS: 11
X_OFFSET: 242 [pixels]
Y_OFFSET: 614 [pixels]
X_MAX: 1201 [pixels]
Y_MAX: 1573 [pixels]
DET_THRESH: 21
PHOTO_THRESH: 13
SL_URL: sw01173731000msufc707706061.fits
SUN_POSTN: 73.84d {+04h 55m 22s} +22.60d {+22d 36' 16"}
SUN_DIST: 79.30 [deg] Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN: 282.08d {+18h 48m 19s} -27.70d {-27d 41' 43"}
MOON_DIST: 125.21 [deg]
MOON_ILLUM: 95 [%]
GAL_COORDS: 183.39, 66.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 152.62, 28.21 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 06 Jun 23 01:05:27 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 1173731, Seg_Num: 0
POINT_RA: 166.783d {+11h 07m 08s} (J2000)
POINT_DEC: +36.504d {+36d 30' 16"} (J2000)
POINT_ROLL: 290.161d
IMG_START_DATE: 20101 TJD; 157 DOY; 23/06/06
IMG_START_TIME: 3661.10 SOD {01:01:01.10} UT
FILTER: 10, White
BKG_MEAN: 6.198
N_STARS: 11
X_OFFSET: 242 [pixels]
Y_OFFSET: 614 [pixels]
X_MAX: 1201 [pixels]
Y_MAX: 1573 [pixels]
DET_THRESH: 21
PHOTO_THRESH: 13
SL_URL: sw01173731000msufc707706061.fits
SUN_POSTN: 73.84d {+04h 55m 22s} +22.60d {+22d 36' 16"}
SUN_DIST: 79.30 [deg] Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN: 282.08d {+18h 48m 19s} -27.70d {-27d 41' 42"}
MOON_DIST: 125.22 [deg]
MOON_ILLUM: 95 [%]
GAL_COORDS: 183.39, 66.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 152.62, 28.21 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Source List.
COMMENTS: If you have elected to receive attachments:
COMMENTS: The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 06 Jun 23 01:06:37 UT
NOTICE_TYPE: Swift-UVOT Image
TRIGGER_NUM: 1173731, Seg_Num: 0
POINT_RA: 166.783d {+11h 07m 08s} (J2000)
POINT_DEC: +36.504d {+36d 30' 16"} (J2000)
ROLL: 290.161d
IMG_START_DATE: 20101 TJD; 157 DOY; 23/06/06
IMG_START_TIME: 3661.10 SOD {01:01:01.10} UT
FILTER: 10, White
EXPOSURE_ID: 707706092
X_OFFSET: 561 [pixels]
Y_OFFSET: 933 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 721
Y_GRB_POS: 1093
BINNING_INDEX: 1
IM_URL: sw01173731000msuni707706093.fits
SUN_POSTN: 73.84d {+04h 55m 22s} +22.60d {+22d 36' 16"}
SUN_DIST: 79.30 [deg] Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN: 282.09d {+18h 48m 23s} -27.69d {-27d 41' 40"}
MOON_DIST: 125.23 [deg]
MOON_ILLUM: 95 [%]
GAL_COORDS: 183.39, 66.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 152.62, 28.21 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Image.
COMMENTS: The GRB Position came from the Window Position in the Mode Command.
COMMENTS: The image has 2x2 binning (compression).
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 06 Jun 23 01:06:43 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 1173731, Seg_Num: 0
POINT_RA: 166.783d {+11h 07m 08s} (J2000)
POINT_DEC: +36.504d {+36d 30' 16"} (J2000)
ROLL: 290.161d
IMG_START_DATE: 20101 TJD; 157 DOY; 23/06/06
IMG_START_TIME: 3661.10 SOD {01:01:01.10} UT
FILTER: 10, White
EXPOSURE_ID: 707706092
X_OFFSET: 561 [pixels]
Y_OFFSET: 933 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 721
Y_GRB_POS: 1093
BINNING_INDEX: 1
IM_URL: sw01173731000msuni707706093.fits
SUN_POSTN: 73.84d {+04h 55m 22s} +22.60d {+22d 36' 16"}
SUN_DIST: 79.30 [deg] Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN: 282.10d {+18h 48m 23s} -27.69d {-27d 41' 40"}
MOON_DIST: 125.23 [deg]
MOON_ILLUM: 95 [%]
GAL_COORDS: 183.39, 66.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 152.62, 28.21 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Image.
COMMENTS: The GRB Position came from the Window Position in the Mode Command.
COMMENTS: The image has 2x2 binning (compression).
COMMENTS: If you have elected to receive attachments:
COMMENTS: The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.
- GCN Circular #33921
A. Y. Lien (U Tampa), J.D. Gropp (PSU), J. A. Kennea (PSU),
D. M. Palmer (LANL), T. M. Parsotan (GSFC/UMBC/CRESSTII) and
B. Sbarufatti (INAF-OAB) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 00:14:37 the Swift Burst Alert Telescope (BAT) triggered and
located GRB 230606A (trigger=1173731). Due to communications problems
from a recent typhoon in Guam, only limited real-time data is
available and notices are being delayed. Swift had a delayed slew
to the burst, presumably due to observing constraints.
The ground-calculated BAT location based on available data is
RA, Dec 166.7956 36.5090.
There is no immediately-available BAT lightcurve data for
this GRB, however the BAT trigger duration was on the 2 second
timescale, suggesting a long GRB.
Using promptly downlinked data we find an uncatalogued X-ray source
located at RA, Dec 166.81107, 36.48427 which is equivalent to:
RA(J2000) = 11h 07m 14.66s
Dec(J2000) = +36d 29' 03.4"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
position may be improved as more data are received; the latest position
is available at https://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (2.32 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 4
(+2.97/-2.57) x 10^21 cm^-2 (90% confidence).
Further information will be available after the complete data
download at the next ground pass.
Burst Advocate for this burst is A. Y. Lien (yarleen AT gmail.com).
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/)
- GCN Circular #33924
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1707 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 230606A, 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 = 166.80951, +36.48425 which is equivalent
to:
RA (J2000): 11h 07m 14.28s
Dec (J2000): +36d 29' 03.3"
with an uncertainty of 2.2 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) and Evans
et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
- GCN Circular #33926
A. A. Breeveld (UCL-MSSL) and A. Y. Lien (U. Tampa) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 230606A 2784 s after the BAT trigger (Lien et al., GCN Circ. 33921).
No optical afterglow consistent with the XRT position (Goad et al., GCN Circ. 33924) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 2784 2934 147 >20.3
white 2784 3554 344 >21.1
v 3765 3965 197 >19.2
b 3149 3349 197 >20.2
u 2943 4514 328 >20.1
w1 4176 4376 197 >20.2
w2 3560 3760 197 >20.3
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.015 in the direction of the burst (Schlegel et al. 1998).
- GCN Circular #33928
T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), M.G. Bernardini
(INAF-OAB), A. Tohuvavohu (U. Toronto), D.N. Burrows (PSU), J. D. Gropp
(PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A.
Evans (U. Leicester) report on behalf of the Swift-XRT team:
We have analysed 6.8 ks of XRT data for GRB 230606A, from 2.8 ks to
43.5 ks after the BAT trigger. The data are entirely in Photon
Counting (PC) mode.
The light curve can be modelled with a power-law decay with a decay
index of alpha=1.16 (+0.09, -0.08).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.05 (+0.18, -0.17). The
best-fitting absorption column is 1.2 (+0.5, -0.4) x 10^21 cm^-2, in
excess of the Galactic value of 2.3 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.3 x 10^-11 (4.2 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.2 (+0.5, -0.4) x 10^21 cm^-2
Galactic foreground: 2.3 x 10^20 cm^-2
Excess significance: 3.7 sigma
Photon index: 2.05 (+0.18, -0.17)
If the light curve continues to decay with a power-law decay index of
1.16, the count rate at T+24 hours will be 0.010 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.3 x
10^-13 (4.3 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01173731.
This circular is an official product of the Swift-XRT team.
- GCN Circular #33930
Y.-D. Hu, E. Fernandez-Garcia, A. J. Castro-Tirado, I. Perez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy (IAA-CSIC), D. Hiriart and W. H. Lee (UNAM), C. J. Perez del Pulgar (UMA) and I. M. Carrasco-Garcia (SMA) and I. H. Park (SKKU), on behalf of a larger collaboration, report:
Following the detection of GRB 230606A by Swift (Lien et al. GCNC 33921), we triggered the BOOTES-5/JGT 0.6m robotic telescope at Observatorio Astronomico Nacional in San Pedro Martir (Mexico) to observe the GRB location starting on Jun. 06, 04:27:09 UT (~ 4.2 hrs after trigger). A series of images in clear filter were gathered. No new optical source is detected within the enhanced Swift/XRT error region (Goad et al. GCNC 33924) down to 20.3 mag, which is consistent with the limits reported by UVOT (Breeveld et al. GCNC 33926).
We thank the staff at Observatorio Astronomico Nacional in San Pedro Martir for their excellent support.
- GCN Circular #33931
S. Dalessi (UAH) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 00:14:38.13 UT on 06 June 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 230606A (trigger 707703283/230606010).
which was also detected by Swift BAT (A. Y. Lien et al. 2023, GCN 33921).
The Fermi GBM on-ground location is consistent with the Swift BAT position.
The angle from the Fermi LAT boresight is 110 degrees.
The GBM light curve consists of multiple peaks with a duration (T90)
of about 16 s (50-300 keV). The time-averaged spectrum
from T0-1.8 to T0+18.7 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.7 +/- 0.2 and the cutoff energy,
parameterized as Epeak, is 148 +/- 22 keV.
The event fluence (10-1000 keV) in this time interval is
(2.5 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2.4 s in the 10-1000 keV band is 3.4 +/- 0.3 ph/s/cm^2.
A Band function fits the spectrum equally well
with Epeak= 98 +/- 25 keV, alpha = -0.2 +/- 0.5 and beta = -2.1 +/- 0.2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
- GCN Circular #33932
S.Y. Fu, T.H. Lu, S.Q. Jiang, X. Liu, Z.P. Zhu, D Xu (NAOC), S.W. Luo, M.M. Yang, Z. K. Feng (GYZO, NAOC) report:
We observed the field of GRB 230606A detected by Swift (Lien et al., GCN 33921) with the GOT-0.5m telescope located at Gaoyazi, Xinjiang, China. We obtained 20x180 s frames in the Sloan r-band and 15x180 s frames in the Sloan z-band, starting at 16:25:45 UT on 2023-06-06, i.e., 16.18 hr after the Swift/BAT trigger.
No optical source is detected in our stacked images at the enhanced XRT position (Goad et al., GCN 33924), and preliminary photometric results are as follows:
T_mid-T0 (hr) Filter Upper_Limit (3-sigma)
16.74 r >20.9
18.05 z >18.1
calibrated with the nearby PanSTARRS field and not corrected for Galactic extinction.
- GCN Circular #33933
A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU),
M. Stamatikos (OSU) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 230606A (trigger #1173731)
(Lien et al., GCN Circ. 33921). The BAT ground-calculated position is
RA, Dec = 166.777, 36.504 deg which is
RA(J2000) = 11h 07m 06.4s
Dec(J2000) = +36d 30' 15.6"
with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 15%.
The mask-weighted light curve shows two distinct pulses. The first pulse starts
at ~T0 and ends at ~T+4 s. The second pulse starts at ~T+14 s and ends at ~T+16 s.
T90 (15-350 keV) is 16.26 +- 1.29 sec (estimated error including systematics).
The time-averaged spectrum from T-0.26 to T+16.97 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.15 +- 0.30. The fluence in the 15-150 keV band is 1.2 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.92 sec in the 15-150 keV band
is 2.6 +- 0.6 ph/cm2/sec. 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/1173731/BA/
- GCN Circular #33956
R. Strausbaugh (University of Minnesota), A. Cucchiara (NASA) report on
behalf of a larger collaboration:
We observed the GRB 230606A (Lien et al., GCN 33921) field with the LCOGT
1-meter Sinistro instrument at the McDonald Observatory, Texas, USA site,
on June 6, from 02:58 to 03:30 UT (corresponding to 2.73 to 3.27 hours from
the GRB trigger time) with the SDSS r and i filters.
We performed a series of 3x300s exposures in each band. We detect an
uncataloged source within the Swift-XRT enhanced error region (Goad et al.,
GCN 33924). Later time upper limits (Hu et al., GCN 33930) are consistent
with the fading of this source, suggesting that it is the optical
afterglow; however, the later upper limit could be a result of the redness
of this source.
The following magnitudes are calculated using the PanSTARRS catalog as
reference:
r > 20.95 +/- 0.06
i > 19.66 +/- 0.04
These magnitudes are not corrected for galactic extinction.
Previous IAU Circulars 