- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Mon 15 Jul 24 05:44:32 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 46
TRIGGER_NUM: 742715048
GRB_RA: 358.883d {+23h 55m 32s} (J2000),
359.200d {+23h 56m 48s} (current),
358.235d {+23h 52m 56s} (1950)
GRB_DEC: -48.133d {-48d 07' 59"} (J2000),
-47.997d {-47d 59' 47"} (current),
-48.412d {-48d 24' 41"} (1950)
GRB_ERROR: 3.58 [deg radius, statistical plus systematic]
GRB_INTEN: 2990 [cnts/sec]
DATA_SIGNIF: 49.90 [sigma]
INTEG_TIME: 0.128 [sec]
GRB_DATE: 20506 TJD; 197 DOY; 24/07/15
GRB_TIME: 20643.26 SOD {05:44:03.26} UT
GRB_PHI: 112.00 [deg]
GRB_THETA: 55.00 [deg]
DATA_TIME_SCALE: 0.1280 [sec]
HARD_RATIO: 0.37
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 96% GRB
2nd_MOST_LIKELY: 3% Generic Transient
DETECTORS: 1,1,0, 0,0,0, 0,0,0, 1,1,0, 0,0,
SUN_POSTN: 115.08d {+07h 40m 20s} +21.43d {+21d 26' 05"}
SUN_DIST: 122.92 [deg] Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN: 214.24d {+14h 16m 57s} -16.19d {-16d 11' 18"}
MOON_DIST: 108.60 [deg]
MOON_ILLUM: 62 [%]
GAL_COORDS: 326.62,-66.34 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 335.21,-42.69 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240715239/quicklook/glg_lc_medres34_bn240715239.gif
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 239.82,-23.08 [deg].
COMMENTS: The LC_URL file will not be created until ~15 min after the trigger.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Mon 15 Jul 24 05:44:50 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 58
TRIGGER_NUM: 742715048
GRB_RA: 2.570d {+00h 10m 17s} (J2000),
2.880d {+00h 11m 31s} (current),
1.937d {+00h 07m 45s} (1950)
GRB_DEC: -33.290d {-33d 17' 23"} (J2000),
-33.154d {-33d 09' 12"} (current),
-33.568d {-33d 34' 04"} (1950)
GRB_ERROR: 4.56 [deg radius, statistical only]
DATA_SIGNIF: 50.50 [sigma]
DATA_INTERVAL: 0.128 [sec]
GRB_DATE: 20506 TJD; 197 DOY; 24/07/15
GRB_TIME: 20643.26 SOD {05:44:03.26} UT
GRB_PHI: 114.00 [deg]
GRB_THETA: 70.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 4173 (Gnd S/W Version number)
SUN_POSTN: 115.08d {+07h 40m 20s} +21.43d {+21d 26' 05"}
SUN_DIST: 119.63 [deg] Sun_angle= 7.5 [hr] (West of Sun)
MOON_POSTN: 214.24d {+14h 16m 58s} -16.19d {-16d 11' 22"}
MOON_DIST: 122.28 [deg]
MOON_ILLUM: 62 [%]
GAL_COORDS: 355.70,-79.19 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 347.58,-31.23 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240715239/quicklook/glg_lc_medres34_bn240715239.gif
POS_MAP_URL: http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_742715048.fits
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: Bright hard burst in the GBM.
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: Mon 15 Jul 24 05:53:10 UT
NOTICE_TYPE: Fermi-GBM Final Position
RECORD_NUM: 0
TRIGGER_NUM: 742715048
GRB_RA: 8.390d {+00h 33m 34s} (J2000),
8.693d {+00h 34m 46s} (current),
7.772d {+00h 31m 05s} (1950)
GRB_DEC: -29.420d {-29d 25' 11"} (J2000),
-29.285d {-29d 17' 05"} (current),
-29.696d {-29d 41' 43"} (1950)
GRB_ERROR: 2.97 [deg radius, statistical only]
GRB_DATE: 20506 TJD; 197 DOY; 24/07/15
GRB_TIME: 20643.26 SOD {05:44:03.26} UT
GRB_PHI: 110.00 [deg]
GRB_THETA: 75.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 41731 (Gnd S/W Version number)
SUN_POSTN: 115.09d {+07h 40m 21s} +21.43d {+21d 26' 01"}
SUN_DIST: 114.07 [deg] Sun_angle= 7.1 [hr] (West of Sun)
MOON_POSTN: 214.31d {+14h 17m 14s} -16.22d {-16d 13' 03"}
MOON_DIST: 128.21 [deg]
MOON_ILLUM: 62 [%]
GAL_COORDS: 1.68,-85.45 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 354.78,-30.08 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240715239/quicklook/glg_lc_medres34_bn240715239.gif
LOC_URL: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240715239/quicklook/glg_locplot_all_bn240715239.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: Bright hard burst in the GBM.
COMMENTS: This is likely a Short GRB.
COMMENTS:
COMMENTS: NOTE: This GBM event is temporally(2.0<100sec) coincident with the INTEGRAL_SPIACS event (trignum=10791).
- GCN Circular #36866
The Fermi GBM team reports the detection of a likely SHORT GRB
At 05:44:03 UT on 15 Jul 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240715A (trigger 742715048.256066 / 240715239).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 8.4, Dec = -29.4 (J2000 degrees, equivalent to J2000 00h 33m, -29d 23'), with a statistical uncertainty of 3.0 degrees.
The angle from the Fermi LAT boresight is 75.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240715239/quicklook/glg_skymap_all_bn240715239.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/bn240715239/quicklook/glg_healpix_all_bn240715239.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240715239/quicklook/glg_lc_medres34_bn240715239.gif
- GCN Circular #36872
A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the HEND/Mars Odyssey team,
A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin,
and T. Cline on behalf of the Konus-Wind team,
A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,
E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
and
W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr,
and A.S. Gardner on on behalf of the GRS-Odyssey GRB team,
report:
The short-duration GRB 240715A
(Fermi-GBM detection: The Fermi GBM team, GCN 36866)
was detected by Fermi (GBM trigger 742715048),
Konus-Wind, INTEGRAL (SPI-ACS), and Mars-Odyssey (HEND)
at about 20642 s UT (05:44:02).
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
5.271 (00h 21m 05s) -36.521 (-36d 31' 16")
Corners:
5.188 (00h 20m 45s) -36.486 (-36d 29' 11")
5.394 (00h 21m 35s) -36.672 (-36d 40' 20")
5.354 (00h 21m 25s) -36.556 (-36d 33' 22")
5.148 (00h 20m 36s) -36.369 (-36d 22' 09")
---------------------------------------------
The error box area is 48 sq. arcmin, and its maximum
dimension is 22 arcmin (the minimum one is 3 arcmin).
The Sun distance was 118 deg.
The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM final localization.
Swift ToO has been submitted.
This localization may be improved.
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB240715_T20645/IPN/
The HEALPix triangulation map is the multi-order HEALPix in units of
probability density.
The Konus-Wind time history and spectrum will be given
in a forthcoming GCN Circular.
- GCN Circular #36873
T. Hussenot-Desenonges, P. Hello (IJCLAB), N. Kochiashvili (AbAO), R. Strausbaugh (EIU), C. Andrade (UMN), S. Antier (OCA), M. Coughlin (UMN), P-A Duverne (APC), N. Guessoum (AUS), S. Karpov (FZU), T. Pradier (Unistra/IPHC), D. Turpin (CEA-Saclay/Irfu), A. Klotz (CNRS-OMP-IRAP), M. Boer, S. Gervasoni, C. Limonta (OCA), De Almeida, L., Corradi, W. , Tosta e Melo, I, Sasaki, N., Navarete, F., Braga, L. (LNA) on behalf of the GRANDMA collaboration.
GRANDMA performed follow-up in response to the GRB240715A (presumably short GRB) detected by Fermi GBM (GCN 36866). TAROT-TCH observed the first image at 2024-07-15T07:21:24, 1.5 hours after the trigger time, and OPD started observations at 2024-07-15T08:06:49, 2.5 hours from trigger.
We did not detect any new source with SNR>5 in a 2x1.8 degrees field with RA from 7.5 to 9.6 degrees and DEC from -28.5 to -30.2 degrees; observed by TAROT-TCH in Clear, r,i and z at T0+1.5h, T0+3h, T0+4.5h and T0+5h respectively. The 5-sigma upper-limits we obtain are repectively 19.8, 20.2, 19.4 and 16.7, in G, r, i and z filters (AB magnitudes).
In the OPD field of view, a 0.2x0.2 degrees box centered on RA,DEC:8.396,-29.397 ; we obtain a deeper upperlimit of 21.3 in R filter (Vega magnitude).
TAROT-TCH and OPD data have been reduced by a single data processing pipeline STDPIPE (Karpov et al., 2022)
GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 49, 5518).
- GCN Circular #36875
C. de Barra (UCD) and C. Meegan (UAH) reports on behalf of the Fermi Gamma-=
ray Burst Monitor Team:
At 05:44:03.26 UT on 15 July 2024, the Fermi Gamma-ray Burst Monitor (GBM) =
triggered and located GRB 240715A (trigger 742715048/240715239). The Final =
Real-time Localization was reported previously (Fermi GBM Team 2024, GCN 36=
866).
The angle from the Fermi LAT boresight is 75 degrees.
The GBM light curve consists of a single emission episode with a duration (=
T90)
of about 0.16 s (50-300 keV). The time-averaged spectrum from T0-0.06 to T0=
+0.19
is is best fit by a power law function with an exponential high-energy cuto=
ff.
The power law index is -0.82 +/- 0.03 and the cutoff energy,
parameterized as Epeak, is 2323 +/- 232 keV.=20
The spectrum is equally well fit by a Band function with Epeak =3D 2275 +/-=
267 keV, alpha =3D -0.82 +/- 0.03 and beta =3D -3.86 +/- 1.75.
The event fluence (10-1000 keV) in this time interval is
(2.9 +/- 0.9)E-06 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0.064 s in the 10-1000 keV band is 47 +/- 2 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 #36877
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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 240715A ( Fermi GBM team, GCN 36866) errorbox 56006 sec after notice time and 56048 sec after trigger time at 2024-07-15 21:18:11 UT, with upper limit up to 15.4 mag. The observations began at zenith distance = 77 deg. The sun altitude is -68.0 deg.
The galactic latitude b = -86 deg., longitude l = 1 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2530751
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
56078 | 2024-07-15 21:18:11 | MASTER-SAAO | (00h 26m 31.52s , -29d 17m 42.8s) | C | 60 | 13.5 |
56158 | 2024-07-15 21:19:30 | MASTER-SAAO | (00h 35m 42.07s , -29d 19m 06.1s) | C | 60 | 15.4 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
- GCN Circular #36878
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the IPN GRB 240715A.
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021699
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 IPN 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 #36881
SVOM/GRM team: Yue Huang, Yong-Wei Dong, Jiang-Tao Liu, Min Gao, Hao-Xuan G=
uo, Jiang He, Lu Li, Yong-Ye Li, Hong-Wei Liu, Xin Liu, Hao-Li Shi, Li-Ming=
Song, Jian-Chao Sun, You-Li Tuo, Hao-Xi Wang, Jin Wang, Jin-Zhou Wang, Pin=
g Wang, Rui-Jie Wang, Yu-Xi Wang, Bo-Bing Wu, Shao-Lin Xiong, Jian-Ying Ye,
Yi-Tao Yin, Wen-Hui Yu, Fan Zhang, Li Zhang, Peng Zhang, Shuang-Nan Zhang,
Yan-Ting Zhang, Shu-Min Zhao, Xiao-Yun Zhao, Shi-Jie Zheng (IHEP), Maria-G=
razia Bernardini (LUPM/INAF-OAB), Laurent Bouchet (IRAP), David Corre (CEA)=
, Patrick Maeght (LUPM), Fr=C3=A9d=C3=A9ric Piron (LUPM), Jingwei Wang (IAP)
=20
SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (I=
HEP), St=C3=A9phane Basa (LAM), Jean-Luc Att=C3=A9ia (IRAP), Arnaud Claret
(CEA), Zi-Gao Dai (USTC), Fr=C3=A9d=C3=A9ric Daigne (IAP), Jin-Song Deng (N=
AOC), Andrea Goldwurm (APC), Diego G=C3=B6tz (CEA), Xu-Hui Han (NAOC), Cyri=
l Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Ob=
s.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 was triggered by a short GRB 2=
40715A at 2024-07-15T05:44:03.400 UT (T0), which was also observed by Fermi=
/GBM (GCN 36866) and INTEGRAL/SPI-ACS (TrigID 10791).
This is the first GRB triggered by GRM in-flight. The real-time alert data=
and light curves produced were downlinked to the ground through the VHF sy=
stem with low latency.
The light curve shows that this burst consists of a single peak with a dura=
tion of less than 0.8 s, indicating that it is a short burst.
The GRM light curve can be found here:
http://www.bursthub.cn//admin/static/svgrb240715A.png
During this period, the SVOM/ECLAIRs was in configuration mode and did not =
collect scientific data, so there was no observation of this burst with ECL=
AIRs.
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 point of contact for these bursts is: Shao-Lin Xiong (IHEP)(xiongs=
l@ihep.ac.cn)
- GCN Circular #36883
S. Tinyanont, R. Anutarawiramkul, P. Butpan (NARIT), J. An, X. Liu, S.Q. Ji=
ang, S.Y. Fu, Z.P. Zhu, D. Xu, Z. Fan, W.X. Li, N.C. Sun, Y.N. Wang (NAOC)
report on behalf of a large collaboration:
We observed the field of short-hard GRB 240715A detected by Fermi/GBM (Ferm=
i GBM team, GCN 36866), IPN (Kozyrev et al., GCN 36872), and SVOM/GRM (Huan=
g et al., GCN 36881) using the 0.7-m telescope of the Thai Robotic Telescope
(TRT) network, located at Cerro Tololo, Chile. We obtained 3 x 300 s R-band
frames at a median time 24.0 hr after the Fermi trigger.
We observed the "Good" one (R.A. = 00h20m35.12s, Dec.=-36=C2=B023=E2=80=
=B222.4=E2=80=B3) of the three Swift/XRT candidates (https://www.swift.ac.uk/ToO_GRBs/00021699/). No new optical source is detected in the stacked
image at the XRT position, down to a 5-sigma limiting magnitude of R ~ 20.7,
calibrated with SkyMapper stars and not corrected for Galactic extinction.
- GCN Circular #36886
A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin,
A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The short-duration GRB 240715A
(Fermi-GBM detection: The Fermi GBM team, GCN 36866;
de Barra & Meegan, GCN 36875;
IPN triangulation: Kozyrev at al., GCN 36872;
SVOM/GRM In-Flight Trigger: Huang et al., GCN 36881)
triggered Konus-Wind at T0=20645.475 s UT (05:44:05.475).
The burst light curve shows a single pulse,
which starts at ~T0 and has a total duration of ~0.2 s.
The emission is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240715_T20645/
As observed by Konus-Wind, the burst
had a fluence of 7.00(-0.97,+1.02)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0+0.090 s,
of 7.55(-1.72,+1.76)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+0.192 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.73(-0.13,+0.14)
and Ep = 1740(-328,+418) keV (chi2 = 24/48 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.4
(chi2 = 24/47 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
- GCN Circular #36887
Wen-Long Zhang, Shao-Lin Xiong, Wen-Jun Tan, Ce Cai, Chen-Wei Wang, Shi-Jie Zheng, Cheng-Kui Li and Peng Zhang report on behalf of the GECAM team:
GECAM-C detected a bright short burst, GRB 240715A, at 2024-07-15T05:44:03.300 UTC (T0), which was also detected by Fermi/GBM (GCN #36866), SVOM/GRM (GCN #36881), INTEGRAL/SPI-ACS (TrigID 10791), Konus-Wind (GCN #36886).
The light curve of GECAM-C shows a total duration of ~0.2 sec (30-300 keV).
Based on the GECAM-C data and the IPN triangulation location (GCN #36872) of this burst, the GECAM-C time-averaged spectrum from T0-0.1 to T0+0.1 could be adequately fit by a power law with high energy exponential cutoff function with a fluence of about (2.73 +0.33/-0.30) E-6 erg/cm^2 in 10-1000 keV. The power law index is -0.91 +0.11/-0.09 and the Epeak is 2105 +950/-583 keV.
The GECAM-C light curve can be found here:
https://twikinew.ihep.ac.cn/pubgecam/Sandbox/GRB/GRB240715A_LightCurve_v01.png
We note that these results are very preliminary. Refined analysis will be reported later.
Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM) mission originally consists of two microsatellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).
- GCN Circular #36890
V. D'Elia (SSDC & INAF-OAR), A. Tohuvavohu (U. Toronto), D.N. Burrows
(PSU), J. D. Gropp (PSU), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), A.P. Beardmore (U. Leicester), B. Sbarufatti (INAF-OAB), 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 IPN-detected
burst GRB 240715A, collecting 4.7 ks of Photon Counting (PC) mode data
between T0+36.0 ks and T0+54.3 ks.
Three uncatalogued X-ray sources have been detected, however none of
them is above the RASS limit or shows definitive signs of fading.
Therefore, at the present time we cannot identify which, if any, is the
afterglow. Details of these sources are given below:
Source 1:
RA (J2000.0): 5.2342 = 00:20:56.20
Dec (J2000.0): -36.5445 = -36:32:40.1
Error: 6.7 arcsec (radius, 90% conf.)
Count-rate: (1.40 [+0.84, -0.62])e-3 ct s^-1
Distance: 135 arcsec from IPN position.
Source 2:
RA (J2000.0): 5.3550 = 00:21:25.20
Dec (J2000.0): -36.6383 = -36:38:17.9
Error: 7.8 arcsec (radius, 90% conf.)
Count-rate: (1.83 [+1.05, -0.78])e-3 ct s^-1
Distance: 487 arcsec from IPN position.
Flux: (3.3 [+1.9, -1.4])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)
Source 3:
RA (J2000.0): 5.1463 = 00:20:35.12
Dec (J2000.0): -36.3896 = -36:23:22.4
Error: 5.5 arcsec (radius, 90% conf. [Enhanced position])
Count-rate: (4.0 [+1.4, -1.2])e-3 ct s^-1
Distance: 595 arcsec from IPN position.
Flux: (6.7 [+2.3, -1.9])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)
Further analysis is ongoing.
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/00021699.
This circular is an official product of the Swift-XRT team.
- GCN Circular #36891
S. R. Oates (Lancaster U.) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 240715A
36 ks after the Fermi/GBM trigger (Fermi GBM team, GCN Circ. 36866).
The UVOT exposures include the positions of XRT sources 1 and 2, but
XRT source 3 is outside of the UVOT field of view (D'Elia et al., GCN 36890).
In the UVOT exposures, optical sources are found consistent with
XRT source 1 and 2. These sources are also observed in the DSS.
Preliminary magnitudes using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the two XRT sources are:
Source Filter T_start(s) T_stop(s) Exp(s) Mag
XRT source 1 white 36242 54326 4613 20.1+\-0.1
XRT source 2 white 36242 54326 4613 21.8+\-0.2
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).
- GCN Circular #36981
C. Salvaggio (INAF-OAB), K. L. Page (U. Leicester) and P.A. Evans (U.
Leicester) reports on behalf of the Swift-XRT team:
Swift-XRT has performed further follow-up observations of the IPN-detected
burst GRB 240715A (Kozyrev et al., GCN Circ. 36872). The data were
collected between T0+36.0 ks ks and T0+1270 ks, for a total exposure time
of 17.7 ks.
The uncatalogued X-ray source reported by D'Elia et al. ("Source 3"; GCN
Circ. 36890), with a count-rate of 4.0 [+1.4, -1.2]e-3 ct s^-1, is no more
detected: we derive an upper limit of 1.4e-3 ct s^-1. Source 3 shows
significant signs of fading, and is therefore likely the GRB afterglow.
The X-ray afterglow light curve can be modelled with a power-law with no
breaks and decay index alpha > 0.63.
The results of the XRT-team automatic analysis are available at
https://www.swift.ac.uk/xrt_products/00021699.
This circular is an official product of the Swift-XRT team.
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