- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Wed 02 Oct 24 06:14:48 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 47
TRIGGER_NUM: 749542463
GRB_RA: 257.283d {+17h 09m 08s} (J2000),
258.142d {+17h 12m 34s} (current),
255.557d {+17h 02m 14s} (1950)
GRB_DEC: -76.033d {-76d 01' 59"} (J2000),
-76.063d {-76d 03' 44"} (current),
-75.968d {-75d 58' 03"} (1950)
GRB_ERROR: 11.10 [deg radius, statistical plus systematic]
GRB_INTEN: 160 [cnts/sec]
DATA_SIGNIF: 7.60 [sigma]
INTEG_TIME: 4.096 [sec]
GRB_DATE: 20585 TJD; 276 DOY; 24/10/02
GRB_TIME: 22458.76 SOD {06:14:18.76} UT
GRB_PHI: 170.00 [deg]
GRB_THETA: 150.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO: 0.81
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 97% GRB
2nd_MOST_LIKELY: 1% Generic Transient
DETECTORS: 0,0,0, 0,0,0, 0,0,0, 0,1,1, 0,0,
SUN_POSTN: 188.78d {+12h 35m 06s} -3.78d {-03d 46' 58"}
SUN_DIST: 81.45 [deg] Sun_angle= -4.6 [hr] (East of Sun)
MOON_POSTN: 183.74d {+12h 14m 57s} -1.33d {-01d 19' 57"}
MOON_DIST: 84.99 [deg]
MOON_ILLUM: 0 [%]
GAL_COORDS: 316.37,-20.47 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 264.96,-52.82 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241002260/quicklook/glg_lc_medres34_bn241002260.gif
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 243.05,11.25 [deg].
COMMENTS: The LC_URL file will not be created until ~15 min after the trigger.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Wed 02 Oct 24 06:14:57 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 58
TRIGGER_NUM: 749542463
GRB_RA: 299.367d {+19h 57m 28s} (J2000),
300.155d {+20h 00m 37s} (current),
297.756d {+19h 51m 02s} (1950)
GRB_DEC: -75.783d {-75d 46' 59"} (J2000),
-75.715d {-75d 42' 53"} (current),
-75.916d {-75d 54' 58"} (1950)
GRB_ERROR: 10.17 [deg radius, statistical plus systematic]
GRB_INTEN: 187 [cnts/sec]
DATA_SIGNIF: 11.20 [sigma]
INTEG_TIME: 4.096 [sec]
GRB_DATE: 20585 TJD; 276 DOY; 24/10/02
GRB_TIME: 22458.76 SOD {06:14:18.76} UT
GRB_PHI: 172.00 [deg]
GRB_THETA: 140.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO: 0.82
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 97% GRB
2nd_MOST_LIKELY: 1% Generic Transient
DETECTORS: 0,0,0, 0,0,0, 0,0,0, 0,1,1, 0,0,
SUN_POSTN: 188.78d {+12h 35m 06s} -3.78d {-03d 46' 58"}
SUN_DIST: 91.48 [deg] Sun_angle= -7.4 [hr] (East of Sun)
MOON_POSTN: 183.74d {+12h 14m 57s} -1.33d {-01d 19' 59"}
MOON_DIST: 95.00 [deg]
MOON_ILLUM: 0 [%]
GAL_COORDS: 318.75,-30.27 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 281.69,-53.54 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241002260/quicklook/glg_lc_medres34_bn241002260.gif
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 243.05,11.25 [deg].
COMMENTS: The LC_URL file will not be created until ~15 min after the trigger.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Wed 02 Oct 24 06:16:16 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 0
TRIGGER_NUM: 749542463
GRB_RA: 343.970d {+22h 55m 53s} (J2000),
344.365d {+22h 57m 28s} (current),
343.164d {+22h 52m 39s} (1950)
GRB_DEC: -64.400d {-64d 24' 00"} (J2000),
-64.267d {-64d 16' 02"} (current),
-64.667d {-64d 40' 00"} (1950)
GRB_ERROR: 4.28 [deg radius, statistical only]
DATA_SIGNIF: 10.60 [sigma]
DATA_INTERVAL: 15.360 [sec]
GRB_DATE: 20585 TJD; 276 DOY; 24/10/02
GRB_TIME: 22458.76 SOD {06:14:18.76} UT
GRB_PHI: 177.00 [deg]
GRB_THETA: 122.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 41731 (Gnd S/W Version number)
SUN_POSTN: 188.78d {+12h 35m 06s} -3.78d {-03d 47' 00"}
SUN_DIST: 109.58 [deg] Sun_angle= -10.4 [hr] (East of Sun)
MOON_POSTN: 183.75d {+12h 15m 00s} -1.34d {-01d 20' 18"}
MOON_DIST: 112.86 [deg]
MOON_ILLUM: 0 [%]
GAL_COORDS: 321.26,-48.41 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 311.57,-51.26 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241002260/quicklook/glg_lc_medres34_bn241002260.gif
POS_MAP_URL: http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_749542463.fits
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: This is likely a Long GRB.
COMMENTS: This Notice was ground-generated -- not flight-generated.
COMMENTS: The LC_URL file will not be created/available until ~15 min after the trigger.
COMMENTS: The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Wed 02 Oct 24 06:15:06 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 57
TRIGGER_NUM: 749542463
GRB_RA: 325.570d {+21h 42m 17s} (J2000),
325.996d {+21h 43m 59s} (current),
324.704d {+21h 38m 49s} (1950)
GRB_DEC: -54.720d {-54d 43' 11"} (J2000),
-54.606d {-54d 36' 21"} (current),
-54.948d {-54d 56' 53"} (1950)
GRB_ERROR: 8.96 [deg radius, statistical only]
DATA_SIGNIF: 11.40 [sigma]
DATA_INTERVAL: 4.096 [sec]
GRB_DATE: 20585 TJD; 276 DOY; 24/10/02
GRB_TIME: 22458.76 SOD {06:14:18.76} UT
GRB_PHI: 162.00 [deg]
GRB_THETA: 118.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 4173 (Gnd S/W Version number)
SUN_POSTN: 188.78d {+12h 35m 06s} -3.78d {-03d 46' 58"}
SUN_DIST: 111.74 [deg] Sun_angle= -9.1 [hr] (East of Sun)
MOON_POSTN: 183.74d {+12h 14m 58s} -1.33d {-01d 20' 01"}
MOON_DIST: 116.03 [deg]
MOON_ILLUM: 0 [%]
GAL_COORDS: 340.69,-46.13 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 307.35,-38.25 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241002260/quicklook/glg_lc_medres34_bn241002260.gif
POS_MAP_URL: http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_749542463.fits
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
COMMENTS: The LC_URL file will not be created/available until ~15 min after the trigger.
COMMENTS: The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Wed 02 Oct 24 06:23:36 UT
NOTICE_TYPE: Fermi-GBM Final Position
RECORD_NUM: 0
TRIGGER_NUM: 749542463
GRB_RA: 333.770d {+22h 15m 05s} (J2000),
334.212d {+22h 16m 51s} (current),
332.868d {+22h 11m 28s} (1950)
GRB_DEC: -64.300d {-64d 17' 59"} (J2000),
-64.176d {-64d 10' 33"} (current),
-64.549d {-64d 32' 55"} (1950)
GRB_ERROR: 3.70 [deg radius, statistical only]
GRB_DATE: 20585 TJD; 276 DOY; 24/10/02
GRB_TIME: 22458.76 SOD {06:14:18.76} UT
GRB_PHI: 172.00 [deg]
GRB_THETA: 124.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 41731 (Gnd S/W Version number)
SUN_POSTN: 188.78d {+12h 35m 07s} -3.79d {-03d 47' 06"}
SUN_DIST: 107.37 [deg] Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN: 183.80d {+12h 15m 12s} -1.37d {-01d 22' 02"}
MOON_DIST: 110.93 [deg]
MOON_ILLUM: 0 [%]
GAL_COORDS: 325.80,-45.27 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 306.06,-48.63 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241002260/quicklook/glg_lc_medres34_bn241002260.gif
LOC_URL: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241002260/quicklook/glg_locplot_all_bn241002260.png
COMMENTS: Fermi-GBM Final Position.
COMMENTS: This Notice was ground-generated -- not flight-generated.
COMMENTS: The LC_URL file should be available by the time this FINAL notice is produced.
COMMENTS: This notice was generated completely by automated pipeline processing.
COMMENTS: This is likely a Long GRB.
- GCN Circular #37668
The Fermi GBM team reports the detection of a likely LONG GRB
At 06:14:18 UT on 2 Oct 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 241002B (trigger 749542463.76265 / 241002260).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 333.8, Dec = -64.3 (J2000 degrees, equivalent to J2000 22h 15m, -64d 17'), with a statistical uncertainty of 3.7 degrees.
The angle from the Fermi LAT boresight is 124.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241002260/quicklook/glg_skymap_all_bn241002260.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241002260/quicklook/glg_healpix_all_bn241002260.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241002260/quicklook/glg_lc_medres34_bn241002260.gif
- GCN Circular #37671
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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 241002B ( Fermi GBM team, GCN 37668) errorbox 109 sec after notice time and 140 sec after trigger time at 2024-10-02 06:16:39 UT, with upper limit up to 20.2 mag. The observations began at zenith distance = 46 deg. The sun altitude is -46.2 deg.
The galactic latitude b = -46 deg., longitude l = 326 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2622469
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
156 | 2024-10-02 06:16:39 | MASTER-OAFA | (22h 55m 46.58s , -64d 18m 23.5s) | C | 30 | 19.2 |
211 | 2024-10-02 06:17:29 | MASTER-OAFA | (22h 55m 46.87s , -64d 18m 23.8s) | C | 40 | 19.3 |
275 | 2024-10-02 06:18:28 | MASTER-OAFA | (22h 55m 47.17s , -64d 18m 24.2s) | C | 50 | 19.0 |
350 | 2024-10-02 06:19:38 | MASTER-OAFA | (22h 55m 47.59s , -64d 18m 24.2s) | C | 60 | 19.6 |
642 | 2024-10-02 06:24:00 | MASTER-OAFA | (22h 35m 58.92s , -63d 55m 04.6s) | C | 120 | 19.1 |
642 | 2024-10-02 06:24:00 | MASTER-OAFA | (22h 15m 05.38s , -64d 13m 49.3s) | C | 120 | 20.1 |
791 | 2024-10-02 06:26:20 | MASTER-OAFA | (22h 35m 59.49s , -63d 55m 06.9s) | C | 140 | 19.2 |
792 | 2024-10-02 06:26:20 | MASTER-OAFA | (22h 15m 06.01s , -64d 13m 50.4s) | C | 140 | 19.6 |
971 | 2024-10-02 06:28:59 | MASTER-OAFA | (22h 36m 00.21s , -63d 55m 09.0s) | C | 180 | 19.3 |
971 | 2024-10-02 06:28:59 | MASTER-OAFA | (22h 15m 06.82s , -64d 13m 51.6s) | C | 180 | 20.2 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
- GCN Circular #37676
A. Kumar, B. P. Gompertz, D. O'Neill, G. Ramsay, R. Starling, K. Ackley, M.
J. Dyer, J. Lyman, K. Ulaczyk, F. Jimenez-Ibarra, D. Steeghs, D. K. Galloway,
V. Dhillon, P. O'Brien, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall,
E. Palle and D. Pollacco report on behalf of the GOTO collaboration:
We report on observations with the Gravitational-wave Optical Transient
Observer (GOTO; Steeghs et al. 2022, Dyer et al. 2024) in response to Fermi GBM
detected GRB 241002B (Fermi GBM Team, GCN 37668). Targeted observations
were performed using the GOTO-South on 2024-10-02 between 09:17:03 and
09:40:00 UT (+3.05h to +3.43h post-trigger, respectively). Each observation
consisted of 4x90s exposures in the GOTO L-band (400-700 nm).
56 images were taken across 8 unique pointings, covering 239.8 square degrees
within the 90% localisation contour. 79.7% of the total 2D localisation
probability was covered, with an average 5-sigma depth of L = 20.3 mag.
Images were processed immediately after acquisition using the GOTO pipeline.
Difference imaging was performed using deeper template observations of the
same pointings. Source candidates were initially filtered using a classifier
(Killestein et al. 2021) and cross-matched against a variety of contextual
and minor planet catalogues. Human vetting was carried out in real time
on any candidates that passed the above checks.
We identify GOTO24gpc/AT2024xbg as a new candidate optical counterpart with
in the Fermi GBM 90% localisation region. We find no evidence of this source
prior to the GRB trigger time in previous GOTO observations, the ZTF
observations provided by the Lasair broker (Smith et al. 2019), or the ATLAS
forced photometry server (Shingles et al. 2021).
Name | RA(J2000) | Dec(J2000) | Obs_time |=C2=A0 T-T0 (hours) |=C2=A0 Filter | Mag (AB) | Lim. Mag
GOTO24gpc / AT2024xbg | 21:53:16.56 | -58:56:51.98 | 2024-10-02 09:17:20 UT | 3.051 |=C2=A0 L | 19.53 =C2=B1 0.09 | 20.5
We caution that the source position was only covered in a single epoch due
to deteriorating weather conditions at Siding Spring. We therefore have no
information on the rate of evolution of the transient. GOTO has not covered
this position to a depth of at least the discovery magnitude for more than
2 weeks prior to GRB 241002B. Follow-up observations to ascertain the nature of GOTO24gpc / AT2024xbg are encouraged.
Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are
not corrected for Galactic extinction.
GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Obser=
vatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia,
on behalf of a consortium including the University of Warwick, Monash
University, Armagh Observatory & Planetarium, the University of Leicester, the
University of Sheffield, the National Astronomical Research Institute of
Thailand (NARIT), the University of Turku, the University of Portsmouth, the
University of Manchester and the Instituto de Astrofisica de Canarias (IAC).
- GCN Circular #37692
M. Torreiro Mart=C3=ADnez, B. Armas-Chinea, F. Dobrindt, P. Escudero-Coca,
G. Fern=C3=A1ndez-Rodr=C3=ADguez, =C3=81. Garc=C3=ADa Lozano, A. Huertas F=
errer, C. M=C3=A9ndez-Lapido, I. Ortega-Casas, Guillermo Villa (ULL), S.R.
Berlanas, and I. P=C3=A9rez-Fournon (IAC and ULL)
We report on optical follow-up observations of the GOTO optical counterpart
candidate AT 2024xbg / GOTO24gpc (Kumar et al. GCN 37676) of the FERMI lon=
g GRB GRB 241002B (Fermi GBM Team, GCN 37368, trigger 749542463.76265 /
241002260, trigger time 2024-10-02T06:14:18 UT).
We observed the field of AT 2024xbg with one of the Las Cumbres Observatory
Global telescope network (LCOGT) 40-cm telescopes located at the LCOGT nod=
e at Siding Spring Observatory (Australia). Observations were performed usi=
ng one of the LCOGT Planewave Delta Rho 350 telescopes equipped with QHY600
CMOS cameras in the SDSS g=C2=B4and r=C2=B4filters, with 500 sec exposures
in each of the filters.
We detect a faint source at the position of AT 2024xbg (GOTO24gpc) with mag=
nitudes g'=3D 20.18 +/- 0.3 at 2014-10-02T12:26:41 UT and r=C2=B4 =3D 19.90
+/- 0.25 at 2014-10-02T12:35:09 UT, calibrated using stars from the catalo=
g of Gaia DR3 synthetic photometry generated from the Gaia BP/RP mean spect=
ra (Gaia collaboration 2022) and without corrections for Milky Way extinction.
These results are based on observations made with the Las Cumbres Observato=
ry=E2=80=99s education network telescopes that were upgraded through genero=
us support from the Gordon and Betty Moore Foundation (programme IAC2024B-0=
10), as part of a course on Astrophysical Techniques of the Master in
Astrophysics of the Universidad de La Laguna, Tenerife, Spain.
- GCN Circular #37694
A. Kumar, D. O'Neill, B. P. Gompertz, G. Ramsay, R. Starling, K. Ackley, M.
J. Dyer, J. Lyman, K. Ulaczyk, F. Jimenez-Ibarra, D. Steeghs, D. K. Galloway,
V. Dhillon, P. O'Brien, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall,
E. Palle and D. Pollacco report on behalf of the GOTO collaboration:
We report on updated observations with the Gravitational-wave Optical Trans=
ient Observer (GOTO; Steeghs et al. 2022, Dyer et al. 2024) on GRB 241002B =
(Fermi GBM Team, GCN 37668). Follow-up observations of the GOTO optical cou=
nterpart candidate GOTO24gpc/AT2024xbg (Kumar et al. GCN 37676) were perfor=
med by GOTO-South at 2024-10-03 09:03:52 UT (t0+26.83h). The observation c=
onsisted of 4x90s exposure in the GOTO L-band (400-700 nm).
Images were processed immediately after acquisition using the GOTO pipeline.
Difference imaging was performed using deeper template observations of
the same pointings.
GOTO24gpc/AT2024xbg is not detected down to a 3-sigma limiting magnitude of
L > 20.83 mag at t0+26.83h post-trigger. The reported detections of GOTO24=
gpc/AT2024xbg in g and r bands (20.18 =C2=B1 0.3 at t0+6.206h and 19.90 =C2=
=B1 0.25 at t0+6.347h post-trigger, respectively; Torreiro Marinez et al.
GCN 37692) are approximately equivalent to an L-band magnitude of ~20.04 =C2=
=B1 0.20 mags, suggesting a decay rate of =3D t^-0.65=C2=B10.29. Fading is
further supported by a non-detection in ATLAS observations taken at 20:44:38
UT on 2024-10-02 (t0 + 14.51h) with a 3-sigma limiting magnitude of o > 20.6
mags, consistent with the above decay rate.
We encourage further deeper follow-up observations.
Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are
not corrected for Galactic extinction.
GOTO (https://goto-observatory.org)
is a network of telescopes that is principally funded by the STFC and operated
at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring
Observatory in NSW, Australia,
on behalf of a consortium including the University of Warwick, Monash
University, Armagh Observatory & Planetarium, the University of Leicester, the
University of Sheffield, the National Astronomical Research Institute of
Thailand (NARIT), the University of Turku, the University of Portsmouth, the
University of Manchester and the Instituto de Astrofisica de Canarias (IAC).
- GCN Circular #37700
J. Durbak (UMD), O. Guiffreda (UMD), S. Atri (U Rome), A. S. Kutyrev (NASA/GSFC), E. Troja (U Rome), K. De (MIT), S. B. Cenko (NASA/GSFC)
Following the Fermi GBM detection (GCN 37668), we observed the transient field in J and H filters with PRIME ~16 hours after FERMI detection.
At the position of the optical counterpart reported by GOTO (GCN 37676), we detect an uncatalogued source in J and H bands. Using nearby VISTA Hemispherical Survey (VHS) and 2MASS stars for preliminary calibration we derive the following magnitudes, not corrected for Galactic extinction:
Filter | Mag(AB) |
-------|--------------|
J | 20.0 +/- 0.2 |
H | 19.6 +/- 0.1 |
Further observations are planned.
PRIME is a 1.8m telescope with 1.56 square degree FOV (0.5 arcsec/pixel) located in Sutherland, South Africa at the South African Astronomical Observatory (SAAO) (Kutyrev et al. 2023, Yama et al. 2023, Durbak et al. 2024).
We thank the Osaka University observers at PRIME and the staff at SAAO for their support with these observations.
- GCN Circular #37703
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the Fermi/GBM GRB 241002B.
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021721
Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Fermi/GBM event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a
GCN Circular after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.
- GCN Circular #37704
James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto), Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:
Swift/BAT did not localize GRB 241002B onboard (T0: 2024-10-02 06:14:18.76 UTC, Fermi trig 749542463, possibly associated with GOTO24gpc/AT 2024xbg GCN 37676, GCN 37692, GCN 37694, GCN 37700)
The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1).
Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.
The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 9.0 in a 8.192 s analysis time bin, starting at T0 - 2.048 s.
Using the NITRATES analysis, parameter estimation was performed to obtain the localization of this burst in the form of a HEALPIX Multi-Order Coverage (MOC) skymap. This localization accounts for both statistical and systematic errors. More details in the creation and calibration of these maps will soon be published (DeLaunay et al. 2024. in prep)
The 90% credible area is 9,578 deg2 and the 50% credible area is 1,255 deg2.
The integrated probability inside the coded field of view is 13%.
A plot of the probability skymap can be viewed here,
[https://guano.swift.psu.edu/trigger_report?id=749542493/#:~:text=Probability%20Skymap](https://guano.swift.psu.edu/trigger_report?id=749542493/#:~:text=Probability%20Skymap)
The probability skymap file can be downloaded from the link here,
https://guano.swift.psu.edu/files/749542493/0_n_PROBMAP
Instructions on how to read and manipulate this map can be found here,
https://guano.swift.psu.edu/documentation
More details about this burst can be found on the trigger report page here
https://guano.swift.psu.edu/trigger_report?id=749542493
GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches.
A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
- GCN Circular #37707
V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), J.A. Kennea
(PSU), D.N. Burrows (PSU), M. A. Williams (PSU), A.P. Beardmore (U.
Leicester), J.P. Osborne (U. Leicester), C. Salvaggio (INAF-OAB) and
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the
Fermi/GBM-detected burst GRB 241002B, collecting 2.7 ks of Photon
Counting (PC) mode data between T0+134.3 ks and T0+146.1 ks.
One uncatalogued X-ray source has been detected consistent with being
within 8.2 arcsec of the candidate optical counterpart detected by
GOTO: GOTO24gpc/AT2024xbg (Kumar et al., GCN Circ. 37694), it is below
the RASS limit and shows no definitive signs of fading. Therefore, at
the present time we cannot confirm this as the afterglow. Details of
this source are given below:
Source 4:
RA (J2000.0): 328.3201 = 21:53:16.82
Dec (J2000.0): -58.9471 = -58:56:49.6
Error: 3.2 arcsec (radius, 90% conf. [Enhanced position])
Count-rate: 0.0246 [+0.0037, -0.0035] ct s^-1
Distance: 3 arcsec from GOTO position.
Flux: (1.12 [+0.17, -0.16])e-12 erg cm^-2 s^-1 (observed, 0.3-10 keV)
The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
https://www.swift.ac.uk/ToO_GRBs/00021721.
This circular is an official product of the Swift-XRT team.
- GCN Circular #37711
O.J. Roberts (USRA/NASA-MSFC), R. Hamburg (CNRS/IJCLab) and
C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 06:14:18.76 UT on 02 October 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 241002B (trigger 749542463/241002260), which was also
detected by Swift-BAT GUANO (DeLaunay et al. 2024, GCN 37004). It was tentatively
associated with GOTO24gpc/AT 2024xbg (Kumar et al., 2024, GCN 37676, GCN 37694),
though Swift-XRT observations do not find a fading X-ray counterpart
(D'Elia et al., 2024, GCN 37707).
The angle from the Fermi LAT boresight is 124 degrees.
The GBM light curve consists of a single emission episode with a duration (T90)
of about 64 s (50-300 keV). The time-averaged spectrum from T0-2.0 to T0+72.0 s
is best fit by a simple power law function with index -1.77 +/- 0.04.
The event fluence (10-1000 keV) in this time interval is
(6.7 +/- 0.6)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from
T0+0.064 s in the 10-1000 keV band is 3.9 +/- 0.3 ph/s/cm^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 #37712
J. Durbak (UMD), O. Guiffreda (UMD), S. Atri (U Rome), A. S. Kutyrev (NASA/GSFC), E. Troja (U Rome), K. De (MIT), S. B. Cenko (NASA/GSFC)
Following up on the previous PRIME detection (GCN 37700), the transient field was observed a second time ~40 hours after the initial Fermi GBM detection (GCN 37668).
At the position of the optical counterpart reported by GOTO (GCN 37676), and the previously detected PRIME source (GCN 37700) we detect a fading uncatalogued source in J and H bands. Using nearby VISTA Hemispherical Survey (VHS) and 2MASS stars for preliminary calibration we derive the following magnitudes, not corrected for Galactic extinction:
Filter | Mag(AB) |
-------|--------------|
J | 20.6 +/- 0.2 |
H | 20.3 +/- 0.1 |
Further follow-up observations are encouraged.
PRIME is a 1.8m telescope with 1.56 square degree FOV (0.5 arcsec/pixel) located in Sutherland, South Africa at the South African Astronomical Observatory (SAAO) (Kutyrev et al. 2023, Yama et al. 2023, Durbak et al. 2024).
We thank the Osaka University observers at PRIME and the staff at SAAO for their support with these observations.
- GCN Circular #37736
O. Guiffreda (UMD), J. Durbak (UMD), S. Atri (U Rome), A. S. Kutyrev (NASA/GSFC), E. Troja (U Rome), S. B. Cenko (NASA/GSFC)
Following up on the previous PRIME detections (GCN 37700, GCN 37712), the transient field was observed a third time ~64 hours after the initial Fermi GBM detection (GCN 37668).
At the position of the optical counterpart reported by GOTO (GCN 37676), and the previously detected PRIME source (GCN 37700) we detect a fading uncatalogued source in H band. Using nearby VISTA Hemispherical Survey (VHS) and 2MASS stars for preliminary calibration we derive the following magnitude and limit, not corrected for Galactic extinction:
| Filter | Mag(AB) |
|--------|--------------|
| J | > 21.1 |
| H | 20.8 +/- 0.2 |
PRIME is a 1.8m telescope with 1.56 square degree FOV (0.5 arcsec/pixel) located in Sutherland, South Africa at the South African Astronomical Observatory (SAAO) (Kutyrev et al. 2023, Yama et al. 2023, Durbak et al. 2024).
We thank the Osaka University observers at PRIME and the staff at SAAO for their support with these observations.
- GCN Circular #37746
V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), J.A. Kennea
(PSU), D.N. Burrows (PSU), M. A. Williams (PSU), A.P. Beardmore (U.
Leicester), J.P. Osborne (U. Leicester), C. Salvaggio (INAF-OAB) and
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Swift-XRT has conducted further observations of the field of the
Fermi/GBM-detected burst GRB 241002B (GCN Circs. 37668 and 37711), also
detected by Swift-BAT GUANO (GCN Circ. 37704). The observations now
extend from T0+134.5 ks to T0+600.2 ks. The source previously reported,
"Source 4", is fading with 2.8 sigma significance and thus is believed
to be the GRB afterglow. Using 2711 s of PC mode data and 3 UVOT
images, we find an enhanced XRT position (using the XRT-UVOT alignment
and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec =
328.32006, -58.94706 which is equivalent to:
RA (J2000): 21h 53m 16.81s
Dec(J2000): -58d 56' 49.4"
with an uncertainty of 3.2 arcsec (radius, 90% confidence). This
position is 3.2 arcsec from the position of candidate optical
counterpart GOTO24gpc/AT 2024xbg (GCN Circs. 37676 and 37694).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.9 (+0.6, -0.4).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.7 (+0.9, -0.7). The
best-fitting absorption column is 1.3 (+2.8, -0.9) x 10^21 cm^-2,
consistent with the Galactic value of 3.0 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 4.6 x 10^-11 (5.3 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.3 (+2.8, -0.9) x 10^21 cm^-2
Galactic foreground: 3.0 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.7 (+0.9, -0.7)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00021721.
The results of the full analysis of the XRT observations are available
at https://www.swift.ac.uk/ToO_GRBs/00021721.
This circular is an official product of the Swift-XRT team.
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