- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Thu 05 Sep 24 18:26:22 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 1252695, Seg_Num: 0
GRB_RA: 345.799d {+23h 03m 12s} (J2000),
346.092d {+23h 04m 22s} (current),
345.208d {+23h 00m 50s} (1950)
GRB_DEC: +35.495d {+35d 29' 42"} (J2000),
+35.628d {+35d 37' 42"} (current),
+35.226d {+35d 13' 32"} (1950)
GRB_ERROR: 3.00 [arcmin radius, statistical only]
GRB_INTEN: 2923 [cnts] Image_Peak=104 [image_cnts]
TRIGGER_DUR: 1.024 [sec]
TRIGGER_INDEX: 155 E_range: 50-350 keV
BKG_INTEN: 12856 [cnts]
BKG_TIME: 66349.87 SOD {18:25:49.87} UT
BKG_DUR: 8 [sec]
GRB_DATE: 20558 TJD; 249 DOY; 24/09/05
GRB_TIME: 66363.63 SOD {18:26:03.63} UT
GRB_PHI: 128.75 [deg]
GRB_THETA: 37.68 [deg]
SOLN_STATUS: 0x83
RATE_SIGNIF: 29.37 [sigma]
IMAGE_SIGNIF: 6.52 [sigma]
MERIT_PARAMS: +1 +0 +0 +0 +3 -4 +0 +0 +74 +0
SUN_POSTN: 164.96d {+10h 59m 50s} +6.42d {+06d 25' 06"}
SUN_DIST: 137.94 [deg] Sun_angle= 11.9 [hr] (West of Sun)
MOON_POSTN: 191.69d {+12h 46m 45s} -5.70d {-05d 41' 54"}
MOON_DIST: 141.93 [deg]
MOON_ILLUM: 6 [%]
GAL_COORDS: 99.32,-22.37 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 3.46, 37.75 [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: Since the IMAGE_SIGNIF is less than 7 sigma, this is a questionable detection.
COMMENTS: This trigger occurred at longitude,latitude = 157.14,20.37 [deg].
- red DSS finding chart
ps-file
- GCN NOTICE
TITLE: GCN/INTEGRAL NOTICE
NOTICE_DATE: Thu 05 Sep 24 18:26:54 UT
NOTICE_TYPE: INTEGRAL SPI ACS Trigger
TRIGGER_NUM: 10891, Sub_Num: 0
GRB_INTEN: 10.91 [sigma]
GRB_TIME: 66362.36 SOD {18:26:02.36} UT
GRB_DATE: 20558 TJD; 249 DOY; 24/09/05
COMMENTS: INTEGRAL SPI_ACS GRB Trigger.
COMMENTS: Time_Scale=2.0000 and Time_Error=1.0000.
COMMENTS:
COMMENTS: NOTE: This SPIACS event is temporally(1.0<100sec) coincident with the SWIFT_BAT event (trignum=1252695).
COMMENTS:
COMMENTS: The SPIACS lightcurve can be found at:
COMMENTS: ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2024-09/2024-09-05T18-26-02.1915-16769-23440-0.lc
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Thu 05 Sep 24 18:28:30 UT
NOTICE_TYPE: Swift-XRT Image
TRIGGER_NUM: 1252695, Seg_Num: 0
GRB_RA: 345.8023d {+23h 03m 12.5s} (J2000),
346.0947d {+23h 04m 22.7s} (current),
345.2113d {+23h 00m 50.7s} (1950)
GRB_DEC: +35.5202d {+35d 31' 12.7"} (J2000),
+35.6535d {+35d 39' 12.5"} (current),
+35.2507d {+35d 15' 02.3"} (1950)
GRB_ERROR: 5.4 [arcsec, radius, statistical plus systematic]
GRB_INTEN: 40 [cnts]
IMG_START_DATE: 20558 TJD; 249 DOY; 24/09/05
IMG_START_TIME: 66470.08 SOD {18:27:50.08} UT, 106.4 [sec] since BAT Trigger Time
CENTROID_X: 263.06, raw= 263 [pixels]
CENTROID_Y: 293.25, raw= 293 [pixels]
ROLL: 1.24 [deg]
GAIN: 1
MODE: 3, Long Image mode
WAVEFORM: 134
EXPO_TIME: 2.50 [sec]
GRB_POS_XRT_Y: -11.41
GRB_POS_XRT_Z: -104.51
IMAGE_URL: sw01252695000msxps_rw.img
SUN_POSTN: 164.96d {+10h 59m 50s} +6.42d {+06d 25' 04"}
SUN_DIST: 137.92 [deg] Sun_angle= 11.9 [hr] (West of Sun)
MOON_POSTN: 191.70d {+12h 46m 48s} -5.71d {-05d 42' 23"}
MOON_DIST: 141.91 [deg]
MOON_ILLUM: 6 [%]
GAL_COORDS: 99.34,-22.34 [deg] galactic lon,lat of the burst
ECL_COORDS: 3.48, 37.77 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Image.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Thu 05 Sep 24 18:28:33 UT
NOTICE_TYPE: Swift-XRT Processed Image
TRIGGER_NUM: 1252695, Seg_Num: 0
GRB_RA: 345.8023d {+23h 03m 12.5s} (J2000),
346.0947d {+23h 04m 22.7s} (current),
345.2113d {+23h 00m 50.7s} (1950)
GRB_DEC: +35.5202d {+35d 31' 12.7"} (J2000),
+35.6535d {+35d 39' 12.5"} (current),
+35.2507d {+35d 15' 02.3"} (1950)
GRB_ERROR: 5.4 [arcsec, radius, statistical plus systematic]
GRB_INTEN: 40 [cnts]
IMG_START_DATE: 20558 TJD; 249 DOY; 24/09/05
IMG_START_TIME: 66470.08 SOD {18:27:50.08} UT, 106.4 [sec] since BAT Trigger Time
CENTROID_X: 263.06, raw= 263 [pixels]
CENTROID_Y: 293.25, raw= 293 [pixels]
ROLL: 1.24 [deg]
GAIN: 1
MODE: 3, Long Image mode
WAVEFORM: 134
EXPO_TIME: 2.50 [sec]
GRB_POS_XRT_Y: -11.41
GRB_POS_XRT_Z: -104.51
IMAGE_URL: sw01252695000msxps_rw.img
SUN_POSTN: 164.96d {+10h 59m 50s} +6.42d {+06d 25' 04"}
SUN_DIST: 137.92 [deg] Sun_angle= 11.9 [hr] (West of Sun)
MOON_POSTN: 191.70d {+12h 46m 48s} -5.71d {-05d 42' 24"}
MOON_DIST: 141.91 [deg]
MOON_ILLUM: 6 [%]
GAL_COORDS: 99.34,-22.34 [deg] galactic lon,lat of the burst
ECL_COORDS: 3.48, 37.77 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Processed Image.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Thu 05 Sep 24 18:28:20 UT
NOTICE_TYPE: Swift-XRT Position
TRIGGER_NUM: 1252695, Seg_Num: 0
GRB_RA: 345.8023d {+23h 03m 12.55s} (J2000),
346.0947d {+23h 04m 22.71s} (current),
345.2113d {+23h 00m 50.70s} (1950)
GRB_DEC: +35.5202d {+35d 31' 12.7"} (J2000),
+35.6535d {+35d 39' 12.5"} (current),
+35.2507d {+35d 15' 02.3"} (1950)
GRB_ERROR: 5.5 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN: 1.11e-09 [erg/cm2/sec]
GRB_SIGNIF: 6.32 [sigma]
IMG_START_DATE: 20558 TJD; 249 DOY; 24/09/05
IMG_START_TIME: 66470.08 SOD {18:27:50.08} UT, 106.4 [sec] since BAT Trigger Time
TAM[0-3]: 327.67 237.13 261.66 243.83
AMPLIFIER: 2
WAVEFORM: 134
SUN_POSTN: 164.96d {+10h 59m 50s} +6.42d {+06d 25' 04"}
SUN_DIST: 137.92 [deg] Sun_angle= 11.9 [hr] (West of Sun)
MOON_POSTN: 191.70d {+12h 46m 48s} -5.71d {-05d 42' 21"}
MOON_DIST: 141.91 [deg]
MOON_ILLUM: 6 [%]
GAL_COORDS: 99.34,-22.34 [deg] galactic lon,lat of the burst
ECL_COORDS: 3.48, 37.77 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Coordinates.
COMMENTS: The XRT position is 1.51 arcmin from the BAT position.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Thu 05 Sep 24 18:29:30 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 1252695, Seg_Num: 0
GRB_RA: 345.799d {+23h 03m 12s} (J2000),
346.092d {+23h 04m 22s} (current),
345.208d {+23h 00m 50s} (1950)
GRB_DEC: +35.495d {+35d 29' 42"} (J2000),
+35.628d {+35d 37' 42"} (current),
+35.226d {+35d 13' 32"} (1950)
GRB_DATE: 20558 TJD; 249 DOY; 24/09/05
GRB_TIME: 66363.63 SOD {18:26:03.63} UT
TRIGGER_INDEX: 155
GRB_PHI: 128.75 [deg]
GRB_THETA: 37.68 [deg]
DELTA_TIME: 64.00 [sec]
TRIGGER_DUR: 1.024 [sec]
SOLN_STATUS: 0x83
RATE_SIGNIF: 29.37 [sigma]
IMAGE_SIGNIF: 6.52 [sigma]
LC_URL: sw01252695000msb.lc
SUN_POSTN: 164.96d {+10h 59m 50s} +6.42d {+06d 25' 03"}
SUN_DIST: 137.94 [deg] Sun_angle= 11.9 [hr] (West of Sun)
MOON_POSTN: 191.71d {+12h 46m 50s} -5.71d {-05d 42' 37"}
MOON_DIST: 141.93 [deg]
MOON_ILLUM: 6 [%]
GAL_COORDS: 99.32,-22.37 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 3.46, 37.75 [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: Since the IMAGE_SIGNIF is less than 7 sigma, this is a questionable detection.
COMMENTS: This trigger occurred at longitude,latitude = 157.14,20.37 [deg].
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Thu 05 Sep 24 18:30:56 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 1252695, Seg_Num: 0
POINT_RA: 345.798d {+23h 03m 11s} (J2000)
POINT_DEC: +35.491d {+35d 29' 28"} (J2000)
POINT_ROLL: 1.244d
IMG_START_DATE: 20558 TJD; 249 DOY; 24/09/05
IMG_START_TIME: 66479.15 SOD {18:27:59.15} UT, 115.5 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 2.277
N_STARS: 85
X_OFFSET: 504 [pixels]
Y_OFFSET: 544 [pixels]
X_MAX: 1463 [pixels]
Y_MAX: 1503 [pixels]
DET_THRESH: 12
PHOTO_THRESH: 6
SL_URL: sw01252695000msufc0115.fits
SUN_POSTN: 164.96d {+10h 59m 50s} +6.42d {+06d 25' 02"}
SUN_DIST: 137.95 [deg] Sun_angle= 11.9 [hr] (West of Sun)
MOON_POSTN: 191.72d {+12h 46m 53s} -5.72d {-05d 42' 57"}
MOON_DIST: 141.93 [deg]
MOON_ILLUM: 6 [%]
GAL_COORDS: 99.32,-22.37 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 3.46, 37.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Thu 05 Sep 24 18:31:10 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 1252695, Seg_Num: 0
POINT_RA: 345.798d {+23h 03m 11s} (J2000)
POINT_DEC: +35.491d {+35d 29' 28"} (J2000)
POINT_ROLL: 1.244d
IMG_START_DATE: 20558 TJD; 249 DOY; 24/09/05
IMG_START_TIME: 66479.15 SOD {18:27:59.15} UT, 115.5 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 2.277
N_STARS: 85
X_OFFSET: 504 [pixels]
Y_OFFSET: 544 [pixels]
X_MAX: 1463 [pixels]
Y_MAX: 1503 [pixels]
DET_THRESH: 12
PHOTO_THRESH: 6
SL_URL: sw01252695000msufc0115.fits
SUN_POSTN: 164.96d {+10h 59m 50s} +6.42d {+06d 25' 01"}
SUN_DIST: 137.95 [deg] Sun_angle= 11.9 [hr] (West of Sun)
MOON_POSTN: 191.72d {+12h 46m 53s} -5.72d {-05d 43' 01"}
MOON_DIST: 141.93 [deg]
MOON_ILLUM: 6 [%]
GAL_COORDS: 99.32,-22.37 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 3.46, 37.74 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Source List.
COMMENTS: All 4 attachments are included.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Thu 05 Sep 24 18:43:47 UT
NOTICE_TYPE: Swift-XRT Position UPDATE
TRIGGER_NUM: 1252695, Seg_Num: 0
GRB_RA: 345.8034d {+23h 03m 12.81s} (J2000),
346.0958d {+23h 04m 22.98s} (current),
345.2124d {+23h 00m 50.96s} (1950)
GRB_DEC: +35.5237d {+35d 31' 25.3"} (J2000),
+35.6570d {+35d 39' 25.1"} (current),
+35.2542d {+35d 15' 14.9"} (1950)
GRB_ERROR: 4.3 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN: 1.00e-10 [erg/cm2/sec]
GRB_SIGNIF: 10.00 [sigma]
IMG_START_DATE: 20558 TJD; 249 DOY; 24/09/05
IMG_START_TIME: 66624.00 SOD {18:30:24.00} UT, 260.4 [sec] since BAT Trigger Time
TAM[0-3]: 100.00 100.00 100.00 100.00
AMPLIFIER: 1
WAVEFORM: 31
SUN_POSTN: 164.97d {+10h 59m 52s} +6.41d {+06d 24' 50"}
SUN_DIST: 137.92 [deg] Sun_angle= 11.9 [hr] (West of Sun)
MOON_POSTN: 191.81d {+12h 47m 15s} -5.77d {-05d 45' 57"}
MOON_DIST: 141.90 [deg]
MOON_ILLUM: 6 [%]
GAL_COORDS: 99.34,-22.34 [deg] galactic lon,lat of the burst
ECL_COORDS: 3.48, 37.77 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
COMMENTS: This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.
COMMENTS: TAM values, flux and significance fields are not valid.
COMMENTS: This position was automatically generated on the ground using
COMMENTS: Photon Counting data telemetered via TDRSS (SPER data).
COMMENTS: See http://www.swift.ac.uk/sper/docs.php for details.
COMMENTS: This is 22.6589256774345" from the X-ray source: 1RXS J230313.6+353105
COMMENTS: in the ROSAT RASSFSC catalogue.
- GCN Circular #37397
S. Dichiara (PSU), J. J. DeLaunay (PSU), R. Gupta (NASA GSFC),
J. A. Kennea (PSU), K. L. Page (U Leicester), T. M. Parsotan (GSFC)
and M. A. Williams (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 18:26:03 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 240905E (trigger=1252695). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 345.799, +35.495 which is
RA(J2000) = 23h 03m 12s
Dec(J2000) = +35d 29' 42"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a complex double-peaked
structure with a duration of about 10 sec. The peak count rate
was ~3000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 18:27:50.0 UT, 106.5 seconds after
the BAT trigger. Using promptly downlinked data we find a bright X-ray
source located at RA, Dec 345.80347, 35.52378 which is equivalent to:
RA(J2000) = 23h 03m 12.83s
Dec(J2000) = +35d 31' 25.6"
with an uncertainty of 4.3 arcseconds (radius, 90% containment). This
location is 104 arcseconds from the BAT onboard position, within the
BAT error circle. This position may be improved as more data are
received; the latest position is available at
https://www.swift.ac.uk/sper. We cannot determine whether the source
is fading at the present time. This position is 22.7 arcseconds from
that of a known X-ray source: 1RXS J230313.6+353105 in the ROSAT
RASSFSC catalogue. Assuming a typical GRB power-law spectrum (NH=3e21
cm^-2, gamma=2), the catalogue entry for this object is equivalent to
a 0.2-10 keV flux of 1.4e-12 erg cm^-2 s^-1; the flux in the 2.5 s XRT
image was 1.11e-09 erg cm^-2 s^-1. No spectrum from the promptly
downlinked event data is yet available to determine the column density.
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 115 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers none of
the XRT error circle. The 8'x8' region for the list of sources generated
on-board covers 100% of the XRT error circle. The list of sources is typically
complete to about 18 mag. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.076.
We note that the X-ray source is near to a catalogued X-ray source, 1RXS
J230313.6+353105. However, this is not a known transient source, and is likely a
chance coincidence. Therefore at this time, we believe that this is a GRB.
Burst Advocate for this burst is S. Dichiara (sbd5667 AT psu.edu).
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 #37398
V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik, D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),
D. Buckley
(South African Astronomical Observatory),
O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)
MASTER-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the Swift GRB 240905E ( S. Dichiara et al., GCN 37397) errorbox 2148 sec after notice time and 2169 sec after trigger time at 2024-09-05 19:02:13 UT, with upper limit up to 15.5 mag. The observations began at zenith distance = 25 deg. The sun altitude is -27.2 deg.
The galactic latitude b = -22 deg., longitude l = 100 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2590673
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
2260 | MASTER-Tunka | C | 180 | 15.5 |
2454 | MASTER-Tunka | C | 180 | 12.6 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
- GCN Circular #37399
J. An, S.Q. Jiang, X. Liu, Z.P. Zhu, S.Y. Fu, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report on behalf of a large collaboration:
We observed the field of GRB 240905E (Dichiara et al., GCN 37397) using the HMT-0.5m telescope located at Nanshan, Xinjiang, China. Observations started at 18:27:59 UT on 2024-09-05, i.e., 116 s after the Swift BAT trigger, and a series of frames were obtained without any filter.
No optical source is detected in our stacked image at the Swift/XRT position (Dichiara et al., GCN 37397), down to a 5-sigma limiting magnitude of ~ 20.9 mag (AB) at 0.676 hr post-burst, calibrated against G-band of Gaia DR3 and not corrected for Galactic extinction.
- GCN Circular #37401
A. S. Moskvitin and O. I. Spiridonova (SAO RAS)
report on behalf of the GRB follow-up team.
We observed the field of GRB 240905E (Dichiara et al., GCN 37397)
using SAO RAS 1-meter telescope Zeiss-1000 equipped with
the New CCD-photometer. The observations started 2024-09-05T18:50:23,
24.3 min after the Swift trigger. We obtained 10 x 60 + 4 x 300 sec.
images in Rc band (t_mid - T0 = 0.69 hours).
Within the XRT error circle (Dichiara et al., GCN 37397) we did not
detect any source down to a limiting magnitude of R_lim = 22.8
calibrated against nearby Pan-STARRS stars (magnitudes converted
to R band) and not corrected for the MW extinction.
- GCN Circular #37402
S. P. R. Shilling (Lancaster U.) and S. Dichiara (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 240905E
95 s after the BAT trigger (Dichiara et al., GCN Circ. 37397).
No optical afterglow consistent with the initial XRT position
(Dichiara et al., GCN Circ. 37397) 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 exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 118 265 145 > 20.64
v 95 106 11 > 17.38
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.057 in the direction of the burst
(Schlegel et al. 1998).
- GCN Circular #37403
R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration:
We observed the Swift GRB 240905E field (Dichiara et al., GCN 37397) with the LCOGT 1-meter Sinistro instrument at the Teide Observatory, Tenerife site, on September 5, from 21:05 to 21:32 UT (corresponding to 2.65 to 3.10 hours after the GRB trigger time) with the sdss r and i filters.
We performed a series of 3x300s exposures in i-band and 1x300s in r-band. We do not detect an uncataloged source within the XRT error region in either band. This result is consistent with other optcal upper limits (Lipunov et al., GCN 37398; An et al., GCN 37399; Moskvitin et al., GCN 37401; Shilling et al., GCN 37402).
The following 5-sigma upper limits are calculated using the PanSTARRS catalog as reference:
r > 22.0
i > 22.2
These magnitudes are not corrected for galactic extinction.
- GCN Circular #37404
SVOM/GRM team: Wen-Long Zhang, Yue Wang, Shi-Jie Zheng, Wen-Jun Tan, Chen-W=
ei Wang, Yong-Wei Dong, Jiang-Tao Liu, Jian-Chao Sun, Yue Huang, Jiang He, =
Min Gao, Hao-Xuan Guo, Lu Li, Yong-Ye Li, Hong-Wei Liu, Xin Liu, Hao-Li Shi=
, Li-Ming Song, You-Li Tuo, Hao-Xi Wang, Jin Wang, Jin-Zhou Wang, Ping Wang=
, Rui-Jie Wang, Yu-Xi Wang, Bo-Bing Wu, Shao-Lin Xiong, Jian-Ying Ye, Yi-Ta=
o Yin, Wen-Hui Yu, Fan Zhang, Li Zhang, Peng Zhang, Shuang-Nan Zhang, Yan-T=
ing Zhang, Shu-Min Zhao, Xiao-Yun Zhao, Chao Zheng (IHEP), Maria-Grazia Ber=
nardini (LUPM/INAF-OAB), Laurent Bouchet (IRAP), David Corre (CEA), Tais Ma=
iolino (LUPM), Fr=C3=A9d=C3=A9ric Piron (LUPM), St=C3=A9phane Schanne (CEA)=
, Jingwei Wang (IAP)
SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (I=
HEP), St=C3=A9phane Basa (LAM), JeanLuc Att=C3=A9ia (IRAP), Arnaud Claret (=
CEA), Zi-Gao Dai (USTC), Fr=C3=A9d=C3=A9ric Daigne (IAP), Jin-Song Deng (NA=
OC), Andrea Goldwurm (APC), Diego G=C3=B6tz (CEA), Xu-Hui Han (NAOC), Cyril=
Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs=
.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Bing Zhang (=
UNLV)
report on behalf of the SVOM team:
During the commissioning phase, the SVOM/GRM triggered in-flight by GRB 240=
0905E (SVOM trigger reference: sb24090503) at 2024-09-05T18:26:03.800 UT (T=
0), which was also observed by Swift/BAT (Neil Gehrels Swift Observatory Te=
am, GCN #37397) and INTEGRAL/SPI-ACS (trigger #10891).
The real-time alert data and light curves of SVOM/GRM were downlinked to th=
e ground through the VHF system with low latency. The light curve shows tha=
t this burst consists of multiple pulses with a duration of about 15 s.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb240905E.png
At the time of the burst ECLAIRs was not in operational mode.
The Space Variable Objects Monitor (SVOM) is a China-France joint mission l=
ed by the Chinese National Space Administration (CNSA, China), National Cen=
ter for Space Studies (CNES, France) and the Chinese Academy of Sciences (C=
AS, China), which is dedicated to observing gamma-ray bursts and other tran=
sient phenomena in the energetic universe. GRM is developed by the Institut=
e of High Energy Physics (IHEP) of CAS.
The SVOM/GRM point of contact for this burst is: Yue Wang (IHEP)(yuewang@ih=
ep.ac.cn)
- GCN Circular #37406
M. Ferro (INAF-OAB), R. Brivio (INAF-OAB), A. D'Ai (INAF-IASFPA), M. A.
Williams (PSU), S. Dichiara (PSU), J.A. Kennea (PSU), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester) and
P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 7.6 ks of XRT data for GRB 240905E, from 96 s to 50.6
ks after the BAT trigger. The data comprise 146 s in Windowed Timing
(WT) mode (the first 9 s were taken while Swift was slewing) with the
remainder in Photon Counting (PC) mode. The refined XRT position is RA,
Dec = 345.8021, +35.5227 which is equivalent to:
RA (J2000): 23 03 12.51
Dec(J2000): +35 31 21.6
with an uncertainty of 4.1 arcsec (radius, 90% confidence).
The light curve can be modelled with an initial power-law decay with an
index of alpha=1.65 (+/-0.13), followed by a break at T+260 s to an
alpha of 4.5 (+3.5, -0.4).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.25 (+/-0.10). The
best-fitting absorption column is 1.3 (+0.5, -0.4) x 10^21 cm^-2,
consistent with the Galactic value of 9.3 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 5.3 x 10^-11 (5.7 x
10^-11) erg cm^-2 count^-1.
A summary of the WT-mode spectrum is thus:
Total column: 1.3 (+0.5, -0.4) x 10^21 cm^-2
Galactic foreground: 9.3 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.25 (+/-0.10)
If the light curve continues to decay with a power-law decay index of
4.5, the count rate at T+24 hours will be 3.0 x 10^-11 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.6 x
10^-21 (1.7 x 10^-21) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01252695.
This circular is an official product of the Swift-XRT team.
- GCN Circular #37408
R. Brivio, M. Ferro, Y.-D. Hu, P. D'Avanzo, S. Covino, D. Fugazza (INAF-OAB) report on behalf of the REM team:
We observed the field of GRB 240905E detected by Swift/BAT (Dichiara et al., GCN 37397) and SVOM/GRM (SVOM/GRM team, GCN 37404) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, J, H, K bands, starting on 2024 September 06 at 01:36:22 UT (i.e. 7.2 hours after the Swift trigger), and lasting for about 1 hour.
From preliminary photometry we do not detect any optical/NIR counterpart at the Swift-XRT refined position (Ferro et al., GCN 37406) down to the following 3sigma magnitude upper limits:
r > 19.1 (AB; calibrated against the PanSTARRS catalogue)
at a mid-time of t - t0 = 7.7 hours after the trigger
J > 17.5 (Vega; calibrated against the 2MASS catalogue)
at a mid-time of t - t0 = 7.8 hours after the trigger.
- GCN Circular #37409
S.Y. Fu (NAOC), L. Izzo (INAF-OACn & DARK/NBI), D. B. Malesani (DAWN/NBI
and Radboud Univ.), D. Xu (NAOC), S.G. Sorensen, A. G. Theil, C. L.
Theil, J. G. Hansen (Aarhus Univ.) report on behalf of a large collaboration:
We observed the field of GRB 240905E detected by Swift/BAT (Dichiara et
al., GCN 37397), and SVOM/GRM (Zhang et al., GCN 37404), using the
2.56-m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera.
We obtained 3 x 300 s frames in the Sloan r-band, and 5 x 200 s as well
as 5 x 300 s frames in z-band, starting at 2024-09-05T20:43:15.4, i.e.,
2.29 hr after the Swift/BAT trigger.
No optical source is detected in our stacked r- and z-band images within
the refined Swift/XRT error circle (Ferro et al., GCN 37406).
Preliminary results are as follows
Tmid time | T-T0(hr) | U.L. (AB, 5 sigma)
---------------------------------------
2024-09-05T20:51:11.5 | 2.42 | 23.8
2024-09-05T22:16:31.5 | 3.84 | 22.7
calibrated with nearby Pan-STARRS stars and not corrected for Galactic
extinction.
- GCN Circular #37412
C. Adami (OSU Pytheas, LAM), M. Dennefeld (Sorbonne U., IAP/CNRS), B. Schne=
ider (MIT),
S. Basa (OSU Pytheas, LAM), F. Sch=C3=BCssler (CEA-Paris Saclay, DPhP), E. =
Le Floc'h (CEA Paris-Saclay, DAp/AIM),
A. Saccardi (GEPI/Obs. de Paris) report on behalf of the MISTRAL GRB collab=
oration:
We observed the field of GRB 240905E (Dichiara et al., GCN 37397; Zhang et =
al., GCN 37404)
using the MISTRAL instrument at the 193cm telescope of Observatoire de Haut=
e-Provence (France).
We performed a series of 5 exposures of 600 sec plus one of 900s in the r=
=E2=80=99-band for a total of
3900 sec on September 5 from 19:34 to 21:05 UT (observation mid-time ~2h af=
ter GRB trigger).
We do not detect any source within the XRT error region.
This result is consistent with the optical upper limits obtained by other g=
roups
(Lipunov et al., GCN 37398; An et al., GCN 37399; Moskvitin et al., GCN 374=
01; Shilling et al.,
GCN 37402; Strausbaugh et al., GCN 37403; Brivio et al., GCN 37408; Fu et a=
l., GCN 37409).
Calibrating our data with the PanSTARRS survey, we obtain the following 3si=
gma lower limit on
the r=E2=80=99 magnitude : r=E2=80=99 > 22.85 (AB). The magnitude is not co=
rrected for Galactic extinction.
We thank the OHP for its excellent support, in particular Jean Pierre Tronc=
in. We also thank the
SOPHIE observer Yasmin Davis.
- GCN Circular #37413
SVOM/C-GFT team: Chao WU (NAOC), Zhe Kang (CHO), Liping Xin(NAOC), Xuhui Ha=
n(NAOC), Pinpin Zhang (NAOC), Xiaomeng Lu (NAOC), Zhenwei Li (CHO), You Lv =
(CHO), Ruosong Zhang (NAOC), Yujie Xiao(NAOC)
SVOM JSWG: Jian-Yan Wei (NAOC, China), Bertrand Cordier (CEA, F), Shuang-N=
an Zhang (IHEP, CN), Stephane Basa (LAM, F), Jean-Luc Att=C3=A9ia (IRAP, F=
), Arnaud Claret (CEA, F), Zi-Gao Dai (USTC, CN), Frederic Daigne (IAP, F),=
Jin-Song Deng (NAOC, CN), Andrea Goldwurm (APC, F), Diego G=C3=B6tz (CEA,=
F), Xu-Hui Han (NAOC, CN), Cyril Lachaud (APC, F), En-Wei Liang (GXU, CN),=
Yu-Lei Qiu (NAOC, CN), Susanna Vergani (Obs.Paris, F), Jing Wang (NAOC, CN=
), Chao Wu(NAOC, CN), Li-Ping Xin (NAOC,CN), Bing Zhang (UNLV, CN)
We observed the field of the GRB 240905E detected by Swift/BAT (Dichiara et=
al., GCN 37397) and SVOM/GRM (Zhang et al., GCN 37404) starting at 18:49:2=
0 UT, 5 Sep. 2024, ~ 0.36 hr after the burst trigger with C-GFT (Chinese Gr=
ound Follow-up Telescope in SVOM mission) in System Test Mode (STM). C-GFT =
is located at Jilin (long.=3D126.33 deg, lat.=3D 43.8243778 deg), Changchun=
Observatory, National Astronomical Observatories, CAS. It has FOV of 1.28 =
deg x 1.28 deg with a 4k*4k CMOS detector mounted on the primary focus of 1=
.2-meter-aperure telescope.
A series of g, r, and i band images were obtained. We obtained stacked imag=
es of g: 108x10s, r: 102x 10s and i: 102x10s. No any optical counterpart wa=
s detected within the X-ray afterglow error circles (Dichiara et al., GCN 3=
7397) down to the limiting magnitude (3 sigma) of mag_g=3D21.5, mag_r=3D21.=
7, and mag_i=3D21.3 . It is consistent with the results reported by Lipunov=
et al.(GCN 37398), Jiang et al. (GCN 37399), Moskvitin et al. (GCN 37401),=
Shilling et al. (GCN 37402), Strausbaugh et al. (GCN 37403), Brivio et al=
. (GCN 37408), Fu et al. (GCN 37409) and Adami et al. (GCN 37412).
The photometry was calibrated with nearby Pan-STARRS 1 catalog.
We thank the observation assistants Bowen Li and Guangsheng Zhang at Jilin =
observatory for their excellent support.
- GCN Circular #37414
Mohammad Odeh (Al-Khatim Observatory, AKO, operated by the International
Astronomical Center in Abu Dhabi, UAE), and Shaikha Alshamsi, Nuha Manal
Pattani, and Nidhal Guessoum (American University of Sharjah, UAE), report:
We observed the field of GRB 240905E (Dichiara et al., GCN 37397) with our
0.36m f/7.7 robotic telescope. The observation started on 5 September 2024
at 18:46 (UT), 21 minutes after the trigger.
We obtained 29x180s images using Ic filter at the position given by
Swift/XRT:
RA (J2000) = 23h 03m 12.83s
Dec (J2000) = +35d 31' 25.6"
We did not detect any credible afterglow candidate at the above position
down to a magnitude of 19.13 for the stacked images. The magnitude was
estimated using the Atlas catalogue as a reference. The magnitude is not
corrected for galactic extinction.
Our observational result is consistent with those of An et al. (GCN 37399),
Moskvitin & Spiridonova (GCN 37401), Strausbaugh et al. (GCN 37403), Brivio
et al. (GCN 37408), and Adami et al. (37412).
- GCN Circular #37415
S. Belkin (HSE, IKI), V. Rumyantsev (CrAO), A. Pozanenko (IKI), and N.
Pankov (HSE, IKI) report on behalf of the IKI GRB FuN:
We observed the field of GRB 240905E (Dichiara et al., GCN 37397) with the
ZTSh 2.6m telescope at the CrAO observatory starting on 2024-09-05 (UT) at
19:36:27. No optical source was detected in a Swift-XRT refined position
(Ferro et al., GCN 37406) up to R = 24.5. However, one source which is
absent in catalogues is near vicinity in XRT localization at coordinates of
(J2000) 23:03:13.149 +35:31:29.74 with uncertainty of 0.5 arcsec is
detected. The source is 5.5" away from the Swift-XRT Initial position
centre (Dichiara et al., GCN 37397) and 11.1" away from the Swift-XRT
refined position (Ferro et al., GCN 37406).
The preliminary photometry of the source is as follows:
Date UT Start t-T0 Filter Exp. OT err UL(3sigma)
(mid, days) (s)
2024-09-05 19:36:27 0.08778 R 6720 22.03 0.05 24.5
The photometry is based on nearby USNO-B1.0 (R2) stars:
RA DEC R2
23:03:16.6228872 +35:31:38.143092 15.84
23:03:10.2213480 +35:31:52.312872 17.59
23:03:23.1021888 +35:32:22.920108 15.81
23:03:10.8221064 +35:34:49.292328 16.04
- GCN Circular #37416
Geoffrey Mo (MIT), Tomas Ahumada (Caltech), Benjamin Schneider (MIT), Viraj Karambelkar (Caltech), Danielle Frostig (CfA), Robert Stein (Caltech), Nathan Lourie (MIT), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) report:
We observed the field of GRB 240905E (Dichiara et al., GCN 37397; Zhang et al., GCN 37404) in the near-infrared J-band with the Palomar 1-m telescope, equipped with the 1 square degree WINTER camera (Lourie et al. 2020).
Observations began at 2024-09-06T02:54:16 UTC (~8.5 hours after the GRB) and consisted of 15 x 120 s exposures. The images were processed using the WINTER data reduction pipeline (https://github.com/winter-telescope/mirar).
We do not detect any sources within the refined Swift/XRT error circle (Ferro et al., GCN 37406), consistent with observations reported by other groups (Lipunov et al., GCN 37398; An et al., GCN 37399; Moskvitin et al., GCN 37401; Shilling et al., GCN 37402; Strausbaugh et al., GCN 37403; Brivio et al., GCN 37408; Fu et al., GCN 37409; Adami et al., GCN 37412; Wu et al., GCN 37413; Odeh et al., GCN 37414; Belkin et al., GCN 37415). We also do not detect a source at the position of the potential CrAO OT candidate (Belkin et al., GCN 37415). We obtain the following 5-sigma upper limit: J ~ 18.6 mag (AB).
WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucille Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research.
- GCN Circular #37419
Z. Maksut (NU), B. Grossan (UCB, NU), T. Komesh (NU), Z. Abdullayev (NU), M. Krugov (FAI) and E. Abdikamalov (NU) report on behalf of the Energetic Cosmos Laboratory:
The Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) observed the field of GRB 240905E, 10 seconds after receipt of an automated GCN / BAT position alert, in Sloan g' and r' bands, with the Burst Simultaneous Three-Channel Imager (Grossan, Kumar & Smoot 2019, JHEA, 32, 14).
We started observations of GRB 240905E (Dichiara et al., GCN 37397) at UT 18:26:58 on 2024-09-05, 55 seconds after the BAT trigger. Observations were made in windy conditions. We report the following upper limit results:
start time t_m-t0(s) end time UL g' UL r' exposure_time (image x s)
-----------------------------------------------------------------------
18:26:58 57 18:27:03 17.01 17.08 10x0.5
18:39:41 908 18:42:41 18.60 18:61 3x60
20:36:14 7991 20:42:14 19.11 19.15 1x360
The start and end time is in UT. t_m is the middle time, t0 is the BAT trigger time, t_m-t0 is given in seconds. UL gives the 5 sigma upper limit sensitivity in magnitudes, for images co-added to the given exposure time. Calibration was done with 4 Pan-STARRS catalog stars on our images. No color corrections were applied to the values above.
----------------------------------
NU = Nazarbayev University, Astana, Kazakhstan
UCB = University of California, Berkeley, USA
FAI = Fesenkov Astrophysical Institute, Kazakhstan
This research has been funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. AP14870504). The NUTTelA-TAO Team acknowledges the support of the staff of the Assy-Turgen Astrophysical Observatory, Almaty, Kazakhstan, and the Fesenkov Astrophysical Institute, Almaty, Kazakhstan.
- GCN Circular #37420
S.Y. Fu, J. An, S.Q. Jiang, X. Liu, Z.P. Zhu, D. Xu (NAOC) report on behalf of a large collaboration:
We observed the field of GRB 240905E detected by Swift/BAT (Dichiara et al., GCN 37397), and SVOM/GRM (Zhang et al., GCN 37404), using the GOT-0.5m telescope located at Gaoyazi, Xinjiang, China. Observations started at 18:26:46 UT on 2024-09-05, i.e., 43 s after the Swift/BAT trigger, and a series of frames were obtained in the Sloan r- and z-filter.
No optical source is detected in our stacked image at the refined Swift/XRT position (Ferro et al., GCN 37406), down to the 5-sigma limiting magnitudes of r > 19.9 mag (AB) at 0.32 hr post-burst and z > 18.7 mag at 2.55 hr post-burst, calibrated with nearby PanSTARRS stars and not corrected for Galactic extinction.
We acknowledge the excellent support from L.F. Huo and M.M. Yang for enabling these observations.
- GCN Circular #37422
T. Mohan, Y. Wagh, R. Kumar, V. Swain, V. Bhalerao (IITB), G.C. Anupama, S.
Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team:
We observed the field of the Swift GRB 240905E (Dichiara et al., GCN 37397)=
with the 0.7m GROWTH-India Telescope (GIT). The observations started at 20=
24-09-05 20:13:28 UT, about 1.78 hours after the Swift BAT trigger. We obta=
ined multiple images of 360s each in r', i' and z' filters respectively. We=
did not detect any new source in our stacked image around the coordinates =
reported by Swift-XRT (Dichiara et al., GCN 37397). Additionally, we examin=
ed the coordinates of the potential OT candidate reported in GCN 37415 by B=
elkin et al., but we did not detect the source at that location. While our =
upper limits are comparable to the reported detection magnitude, deeper obs=
ervations are encouraged to track the source=E2=80=99s evolution. The obtai=
ned upper limits are:
---------------------------------------------------------------------------=
-----------
| JD (mid) | t-t0 (hours) | Filter | Exposure (s) | Limiting Magni=
tude (AB) |
| ----------------- | ------------ | ------ | ------------ | --------------=
--------- |
| 2460559.437685 | 2.28 | r' | 8x360 | 22.4 =
|
| 2460559.460185 | 2.82 | z' | 1x360 | 18.6 =
|
| 2460559.476852 | 3.22 | i' | 4x360 | 20.4 =
|
---------------------------------------------------------------------------=
-----------
Our upper limits are consistent with others (Lipunov et al., GCN 37398; An
et al., GCN 37399; Moskvitin et al., GCN 37401; Swift/UVOT team, GCN 37402;
Strausbaugh et al., GCN 37403; Brivio et al., GCN 37408; Fu et al., GCN
37409, GCN 37412; Adami et al., GCN 37413; WU et al., GCN 37414; Odeh et al.,
GCN 37419; Maksut et al., GCN 37420; Fu et al.). The magnitude are calibra=
ted against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Gal=
actic extinction.
The GROWTH India Telescope (GIT, Kumar et al. 2022) is a 70-cm telescope wi=
th a 0.7-degree field of view, set up by the Indian Institute of Astrophysi=
cs (IIA) and the Indian Institute of Technology Bombay (IITB) with funding
from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observat=
ory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni bat=
ch of 1994, which partially supports the operations of the telescope. Teles=
cope technical details are available at
https://sites.google.com/view/growthindia/.
- GCN Circular #37453
SVOM/VT commissioning team: Y. L.Qiu, L. P. Xin, H. L. Li, C. Wu, X. H. Han=
, H. B. Cai, Y. Xu, Y. J. Xiao, P. P. Zhang, L. Lan, W. J. Xie, X. M. Lu, =
R. S. Zhang, D. W. Xu, G. W. Li (NAOC), J. Zhang, L. J. Dan, G. Y. Zou, C.=
J. Wang, Y. F. Du, C. Huang (XIOPM) and P.Jesse (CEA).
SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (I=
HEP), St=C3=A9phane Basa (LAM), JeanLuc Att=C3=A9ia (IRAP), Arnaud Claret (=
CEA), Zi-Gao Dai (USTC), Fr=C3=A9d=C3=A9ric Daigne (IAP), Jin-Song Deng (NA=
OC), Andrea Goldwurm (APC), Diego G=C3=B6tz (CEA), Xu-Hui Han (NAOC), Cyril=
Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs=
.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Bing Zhang (=
UNLV) report on behalf of the SVOM team:
During the commissioning phase of SVOM mission, we observed the field of th=
e GRB 240905E (Dichiara et al., GCN 37397; Zhang et al., GCN 37404) with S=
VOM/VT telescope in ToO mode. The first observations started at 2024-09-06T=
15:04:16 UT, about 20.6 hours after the burst,and lasted for about 3 ks. Th=
e second observations started at 2024-09-08T12:25:52 UT, about 42.0 hours a=
fter the burst and lasted about 6 ks. VT made the observations with two cha=
nnels simultaneously, VT_B (400nm-650nm) and VT_R (650nm-1000nm).=20
We did not detect any new optical source in the errorbox of Swift-XRT (Fer=
ro et al., GCN 37406) in our stacked images down to the 3 sigma upper limit=
magnitude of about 23.5 mag in AB magnitude for both bands.
Our upper limit results are consistent with others (Lipunov et al., GCN 373=
98; An et al., GCN 37399; Moskvitin et al., GCN 37401; Swift/UVOT team, GCN=
37402; Strausbaugh et al., GCN 37403; Brivio et al., GCN 37408; Fu et al.,=
GCN 37409, GCN 37412; Adami et al., GCN 37413; WU et al., GCN 37414; Odeh =
et al., GCN 37419; Maksut et al., GCN 37420; Fu et al., GCN 37422 Mohan et =
al.).=20
For the optical candidate near the errorbox of the location of X-ray afterg=
low (GCN 37415, Belkin et al.,). It was not detected in VT_B stacked imag=
es in both VT observations, but it was bright in VT_R stacked images in bot=
h observations, and its brightness had no apparent changes in brightness (V=
T_R=3D22.1+/-0.1 mag) in both observations. We also noted that near the pos=
ition of the optical candidate (GCN 37415, Belkin et al.,), there is a fain=
t and red source in the Pan-STARRS catalog with a similar brightness measur=
ed in VT images.
More detailed analysis is ongoing.
=20
The Space Variable Objects Monitor (SVOM) is a China-France joint mission l=
ed by the Chinese National Space Administration (CNSA, China), National Cen=
ter for Space Studies (CNES, France) and the Chinese Academy of Sciences (C=
AS, China), which is dedicated to observing gamma-ray bursts and other tran=
sient phenomena in the energetic universe. VT is an optical telescope on bo=
ard SVOM with an aperture of 44 cm, designed to automatically follow the Ec=
lairs triggers. It has two channels: VT_B and VT_R, covering wavelengths fr=
om 400 nm to 650 nm and 650 nm to 1000 nm, respectively. The two bands are =
observed simultaneously. VT was jointly developed by Xi'an Institute of Opt=
ics and Precision Mechanics (XIOPM), CAS and National astronomical observat=
ories (NAOC),CAS.=20
- GCN Circular #37494
S.Y. Fu (NAOC), J.P.U. Fynbo (DAWN/NBI), L. Izzo (INAF/OAC and DARK/ NBI), D. B. Malesani (DAWN/NBI and Radboud Univ.), D. Xu (NAOC), N. Koivisto (NOT and UTU) report on behalf of a large collaboration:
We observed again the field of GRB 240905E detected by Swift/BAT (Dichiara et al., GCN 37397), and SVOM/GRM (Zhang et al., GCN 37404), using the 2.56-m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. We obtained 8 x 300 s frames in the Sloan r-band, starting at 2024-09-12T04:39:24.2, i.e., 6.43 days after the Swift/BAT trigger.
No new optical transient is detected in our stacked images within the refined Swift/XRT error circle (Ferro et al., GCN 37406), consistent with previous optical upper limits (Lipunov et al., GCN 37398; An et al., GCN 37399; Moskvitin & Spiridonova, GCN 37401; Shilling et al., GCN 37402; Strausbaugh et al., GCN 37403; Brivio et al., GCN 37408; Fu et al., GCN 37409; Adami et al., GCN 37412; Wu et al., GCN 37413; Odeh et al., GCN 37414; Belkin et al., GCN 37415; Mo et al., GCN 37416; Maksut et al., GCN 37419; Fu et al., GCN 37420; Mohan et al., GCN 37422; Qiu et al., GCN 37453). The 5-sigma limiting magnitude is r ~ 23.5 mag, calibrated against nearby Pan-STARRS stars, and not corrected for Galactic extinction.
The optical source report by CrAO (Belkin et al., GCN 37415) is detected in our two epochs at the NOT (Fu et al., GCN 37409). The photometric results are as follow:
Tmid time | T-T0 (days) | Filter | Magnitude (AB)
---------------------------------------
2024-09-05T20:51:11.5 | 0.10 | r |23.09 +- 0.12
2024-09-12T05:15:23.6 | 6.45 | r |23.10 +- 0.15
There is no variability between the two epochs. And the NOT magnitude is also consistent with r = 23.37 +/- 0.27 that we measure from the Pan-STARRS-DR1 r-band image. Also considering the large offset from the refined X-ray position (Ferro et al., GCN 37406), we conclude that this source is unrelated to the GRB.
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