Gamma-ray Burst 240415A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 15 Apr 24 06:27:27 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      45
TRIGGER_NUM:     734855222
GRB_RA:          187.883d {+12h 31m 32s} (J2000),
                 188.152d {+12h 32m 37s} (current),
                 187.326d {+12h 29m 18s} (1950)
GRB_DEC:         +65.967d {+65d 58' 00"} (J2000),
                 +65.833d {+65d 49' 58"} (current),
                 +66.243d {+66d 14' 34"} (1950)
GRB_ERROR:       26.15 [deg radius, statistical plus systematic]
GRB_INTEN:       72 [cnts/sec]
DATA_SIGNIF:     4.80 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        20415 TJD;   106 DOY;   24/04/15
GRB_TIME:        23217.60 SOD {06:26:57.60} UT
GRB_PHI:         105.00 [deg]
GRB_THETA:       115.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      2.12
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      73%  GRB
2nd_MOST_LIKELY:  22%  Generic SGR
DETECTORS:       0,0,1, 0,0,0, 0,0,0, 0,1,0, 0,0,
SUN_POSTN:        23.91d {+01h 35m 38s}   +9.96d {+09d 57' 46"}
SUN_DIST:        103.31 [deg]   Sun_angle= -10.9 [hr] (East of Sun)
MOON_POSTN:      112.27d {+07h 29m 04s}  +27.23d {+27d 13' 54"}
MOON_DIST:        59.59 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:      126.15, 51.04 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      142.28, 59.34 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240415269/quicklook/glg_lc_medres34_bn240415269.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 344.97,2.20 [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 Apr 24 06:27:45 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     734855222
GRB_RA:          168.430d {+11h 13m 43s} (J2000),
                 168.781d {+11h 15m 07s} (current),
                 167.704d {+11h 10m 49s} (1950)
GRB_DEC:         +55.870d {+55d 52' 12"} (J2000),
                 +55.737d {+55d 44' 15"} (current),
                 +56.142d {+56d 08' 33"} (1950)
GRB_ERROR:       17.23 [deg radius, statistical only]
DATA_SIGNIF:     7.50 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        20415 TJD;   106 DOY;   24/04/15
GRB_TIME:        23217.60 SOD {06:26:57.60} UT
GRB_PHI:         113.00 [deg]
GRB_THETA:       126.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:        23.91d {+01h 35m 38s}   +9.96d {+09d 57' 46"}
SUN_DIST:        108.09 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      112.27d {+07h 29m 05s}  +27.23d {+27d 13' 52"}
MOON_DIST:        49.13 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:      147.66, 56.31 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      141.80, 45.62 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240415269/quicklook/glg_lc_medres34_bn240415269.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_734855222.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:     Mon 15 Apr 24 06:28:53 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      0
TRIGGER_NUM:     734855222
GRB_RA:          171.900d {+11h 27m 36s} (J2000),
                 172.242d {+11h 28m 58s} (current),
                 171.192d {+11h 24m 46s} (1950)
GRB_DEC:         +58.550d {+58d 32' 60"} (J2000),
                 +58.416d {+58d 24' 58"} (current),
                 +58.825d {+58d 49' 31"} (1950)
GRB_ERROR:       10.61 [deg radius, statistical only]
DATA_SIGNIF:     10.50 [sigma]
DATA_INTERVAL:   10.240 [sec]
GRB_DATE:        20415 TJD;   106 DOY;   24/04/15
GRB_TIME:        23217.60 SOD {06:26:57.60} UT
GRB_PHI:         111.00 [deg]
GRB_THETA:       124.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:        23.91d {+01h 35m 38s}   +9.96d {+09d 57' 47"}
SUN_DIST:        106.96 [deg]   Sun_angle= -9.9 [hr] (East of Sun)
MOON_POSTN:      112.28d {+07h 29m 07s}  +27.23d {+27d 13' 47"}
MOON_DIST:        51.47 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:      142.09, 55.35 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      141.78, 48.89 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240415269/quicklook/glg_lc_medres34_bn240415269.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_734855222.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:     Mon 15 Apr 24 06:37:14 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     734855222
GRB_RA:          201.640d {+13h 26m 34s} (J2000),
                 201.756d {+13h 27m 02s} (current),
                 201.403d {+13h 25m 37s} (1950)
GRB_DEC:         +75.670d {+75d 40' 12"} (J2000),
                 +75.544d {+75d 32' 40"} (current),
                 +75.929d {+75d 55' 44"} (1950)
GRB_ERROR:       8.18 [deg radius, statistical only]
GRB_DATE:        20415 TJD;   106 DOY;   24/04/15
GRB_TIME:        23217.60 SOD {06:26:57.60} UT
GRB_PHI:          95.00 [deg]
GRB_THETA:       110.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:        23.91d {+01h 35m 39s}   +9.97d {+09d 57' 55"}
SUN_DIST:         94.48 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      112.36d {+07h 29m 27s}  +27.22d {+27d 13' 06"}
MOON_DIST:        63.56 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:      120.05, 41.26 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      127.33, 67.70 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240415269/quicklook/glg_lc_medres34_bn240415269.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240415269/quicklook/glg_locplot_all_bn240415269.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 #36107
The Fermi GBM team reports the detection of a likely LONG GRB
At 06:26:57 UT on 15 Apr 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240415A (trigger 734855222.604114 / 240415269).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 201.6, Dec = 75.7 (J2000 degrees, equivalent to J2000 13h 26m, 75d 42'), with a statistical uncertainty of 8.2 degrees.
The angle from the Fermi LAT boresight is 110.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240415269/quicklook/glg_skymap_all_bn240415269.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/bn240415269/quicklook/glg_healpix_all_bn240415269.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240415269/quicklook/glg_lc_medres34_bn240415269.gif
GCN Circular #36108
M. J. Moss (GSFC), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team:
At 06:26:53 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 240415A (trigger=1221874). Due to a telemetry gap, only limited information is available, specifically the detector plane histogram and associated metadata. Ground analysis of this histogram finds a source at RA, Dec 129.128, +73.169 which is
```
   RA(J2000) = 08h 36m 31s
   Dec(J2000) = +73d 10' 08"
```
The metadata indicates a trigger duration of 1 s, which does not distinguish between a short or a long burst.
We note that this trigger time and position is consistent with Fermi GBM's detection of GRB 240415A (GCN 36107).
Burst Advocate for this burst is M. J. Moss (mikejmoss3 AT gmail.com). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)
GCN Circular #36109
P.A. Evans (U. Leicester), K.L. Page (U. Leicester) and M. J. Moss (GSFC) report on behalf of the Swift-XRT team:
The automated Swift slew to GRB 240415A (BAT trigger 1221874; Moss et al., GCN Circ. 36108) was delayed due to an Earth limb constraint.
The XRT began observing the field at 07:21:58.2 UT, 3305 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 129.19096 73.14608 which is equivalent to:
```
   RA(J2000)  = 08h 36m 45.83s
   Dec(J2000) = +73d 08' 45.9"
```
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This is 105 arcseconds from the BAT position, inside 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.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (2.49 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 6.5 (+3.49/-2.94) x 10^21 cm^-2 (90% confidence).
GCN Circular #36118
N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunko (ISTP), S. Belkin (IKI) report on behalf of GRB-IKI-FuN:
We observed the field of GRB 240415A (Fermi GBM team, GCN 36107; Moss et al., GCN 36108, Evans et al., GCN 36109) with 1.5-meter AZT-33IK telescope of Sayan observatory at Mondy. The observations were started on 2024-04-15 (UT) 14:33:22, i.e. ~8 hr since the Fermi GBM trigger. We took 30 frames 120 s each in the R-filter. We detect a possible optical counterpart in the stacked image at coordinates of (J2000) 08:36:45.26 73:08:47.6 with uncertainties of 0.4 arcsec in both coordinates. Preliminary photometry of the optical source is following:
```
Date       UT_start  MJD           Filter Exp.  OT    err  UL(3sigma)
                    (mid, days)           (s)
2024-04-15 14:33:22  60415.627345  R     44*120 18.84 0.08 21.9
```
The magnitudes were calibrated using nearby USNO-B1.0 stars.

GCN Circular #36119
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-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB 240415A ( Fermi GBM team, GCN 36107) errorbox 43102 sec after notice time and 43137 sec after trigger time at 2024-04-15 18:25:55 UT, with upper limit up to 18.7 mag. The observations began at zenith distance = 35 deg. The sun altitude is -20.0 deg.
MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 240415A errorbox 43114 sec after notice time and 43149 sec after trigger time at 2024-04-15 18:26:07 UT, with upper limit up to 18.6 mag. The observations began at zenith distance = 38 deg. The sun altitude is -25.1 deg.
The galactic latitude b = 42 deg., longitude l = 120 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2423215
We obtain a following upper limits.

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   43168 | 2024-04-15 18:25:55 |      MASTER-Tavrida | (12h 41m 57.43s , +75d 02m 45.2s) |   C |    60 | 18.3 |        
   43180 | 2024-04-15 18:26:07 |   MASTER-Kislovodsk | (13h 58m 04.46s , +75d 29m 04.7s) |   C |    60 | 17.6 |        
   43180 | 2024-04-15 18:26:07 |   MASTER-Kislovodsk | (14h 14m 02.58s , +75d 02m 20.5s) |   C |    60 | 18.5 |        
   43260 | 2024-04-15 18:27:27 |   MASTER-Kislovodsk | (13h 22m 54.58s , +79d 18m 44.3s) |   C |    60 | 17.8 |        
   43260 | 2024-04-15 18:27:27 |   MASTER-Kislovodsk | (13h 44m 16.06s , +78d 51m 50.7s) |   C |    60 | 18.5 |        
   43340 | 2024-04-15 18:28:47 |   MASTER-Kislovodsk | (13h 17m 15.80s , +73d 35m 59.5s) |   C |    60 | 17.8 |        
   43340 | 2024-04-15 18:28:47 |   MASTER-Kislovodsk | (13h 31m 44.89s , +73d 10m 02.8s) |   C |    60 | 18.5 |        
   43374 | 2024-04-15 18:29:21 |      MASTER-Tavrida | (13h 24m 13.00s , +76d 57m 02.6s) |   C |    60 | 18.4 |        
   43420 | 2024-04-15 18:30:07 |   MASTER-Kislovodsk | (12h 51m 52.86s , +76d 57m 52.8s) |   C |    60 | 18.3 |        
   43420 | 2024-04-15 18:30:07 |   MASTER-Kislovodsk | (12h 33m 18.95s , +77d 23m 31.1s) |   C |    60 | 17.5 |        
   43446 | 2024-04-15 18:30:33 |      MASTER-Tavrida | (13h 56m 37.00s , +73d 10m 16.5s) |   C |    60 | 18.3 |        
   43518 | 2024-04-15 18:31:45 |      MASTER-Tavrida | (13h 21m 10.17s , +71d 15m 43.7s) |   C |    60 | 18.4 |        
   43593 | 2024-04-15 18:33:00 |      MASTER-Tavrida | (11h 42m 00.08s , +75d 01m 17.2s) |   C |    60 | 18.5 |        
   43666 | 2024-04-15 18:34:13 |      MASTER-Tavrida | (12h 33m 06.72s , +71d 13m 56.3s) |   C |    60 | 18.6 |        
   43701 | 2024-04-15 18:34:48 |   MASTER-Kislovodsk | (14h 44m 19.50s , +79d 16m 36.9s) |   C |    60 | 17.6 |        
   43701 | 2024-04-15 18:34:48 |   MASTER-Kislovodsk | (15h 05m 01.93s , +78d 48m 27.9s) |   C |    60 | 18.4 |        
   43781 | 2024-04-15 18:36:08 |   MASTER-Kislovodsk | (12h 55m 54.06s , +81d 11m 28.9s) |   C |    60 | 17.8 |        
   43781 | 2024-04-15 18:36:08 |   MASTER-Kislovodsk | (13h 21m 39.24s , +80d 44m 24.4s) |   C |    60 | 18.4 |        
   43861 | 2024-04-15 18:37:28 |   MASTER-Kislovodsk | (14h 51m 26.51s , +77d 23m 02.0s) |   C |    60 | 17.5 |        
   43861 | 2024-04-15 18:37:28 |   MASTER-Kislovodsk | (15h 09m 51.40s , +76d 55m 31.1s) |   C |    60 | 18.2 |        
   43942 | 2024-04-15 18:38:49 |   MASTER-Kislovodsk | (12h 23m 31.82s , +73d 36m 49.8s) |   C |    60 | 17.9 |        
   43942 | 2024-04-15 18:38:49 |   MASTER-Kislovodsk | (12h 38m 13.66s , +73d 11m 56.7s) |   C |    60 | 18.6 |        
   43947 | 2024-04-15 18:38:54 |      MASTER-Tavrida | (11h 40m 21.90s , +79d 27m 06.2s) |   C |    60 | 18.5 |        
   44242 | 2024-04-15 18:43:49 |      MASTER-Tavrida | (12h 41m 57.04s , +75d 02m 13.5s) |   C |    60 | 18.6 |        
   44269 | 2024-04-15 18:44:16 |   MASTER-Kislovodsk | (14h 14m 03.95s , +75d 02m 14.5s) |   C |    60 | 18.2 |        
   44269 | 2024-04-15 18:44:16 |   MASTER-Kislovodsk | (13h 57m 52.27s , +75d 28m 52.9s) |   C |    60 | 17.5 |        
   44314 | 2024-04-15 18:45:01 |      MASTER-Tavrida | (13h 13m 41.15s , +75d 02m 50.4s) |   C |    60 | 18.6 |        
   44350 | 2024-04-15 18:45:37 |   MASTER-Kislovodsk | (13h 44m 12.27s , +78d 52m 16.9s) |   C |    60 | 18.1 |        
   44350 | 2024-04-15 18:45:37 |   MASTER-Kislovodsk | (13h 22m 33.47s , +79d 19m 00.8s) |   C |    60 | 17.5 |        
   44384 | 2024-04-15 18:46:11 |      MASTER-Tavrida | (13h 24m 18.65s , +76d 58m 13.6s) |   C |    60 | 18.5 |        
   44429 | 2024-04-15 18:46:57 |   MASTER-Kislovodsk | (13h 16m 59.43s , +73d 35m 27.9s) |   C |    60 | 17.5 |        
   44429 | 2024-04-15 18:46:57 |   MASTER-Kislovodsk | (13h 31m 36.58s , +73d 09m 38.3s) |   C |    60 | 18.3 |        
   44455 | 2024-04-15 18:47:22 |      MASTER-Tavrida | (14h 00m 34.32s , +76d 57m 07.8s) |   C |    60 | 18.3 |        
   44510 | 2024-04-15 18:48:17 |   MASTER-Kislovodsk | (12h 33m 08.21s , +77d 25m 41.9s) |   C |    60 | 17.4 |        
   44510 | 2024-04-15 18:48:17 |   MASTER-Kislovodsk | (12h 51m 56.28s , +77d 00m 14.0s) |   C |    60 | 18.2 |        
   44525 | 2024-04-15 18:48:33 |      MASTER-Tavrida | (13h 56m 47.31s , +73d 10m 32.5s) |   C |    60 | 18.4 |        
   44590 | 2024-04-15 18:49:37 |   MASTER-Kislovodsk | (14h 21m 25.41s , +71d 41m 13.5s) |   C |    60 | 17.3 |        
   44590 | 2024-04-15 18:49:37 |   MASTER-Kislovodsk | (14h 34m 39.37s , +71d 15m 19.0s) |   C |    60 | 18.1 |        
   44597 | 2024-04-15 18:49:44 |      MASTER-Tavrida | (14h 24m 47.23s , +73d 10m 17.6s) |   C |    60 | 18.3 |        
   44670 | 2024-04-15 18:50:57 |   MASTER-Kislovodsk | (14h 43m 16.62s , +79d 17m 39.9s) |   C |    60 | 17.5 |        
   44670 | 2024-04-15 18:50:57 |   MASTER-Kislovodsk | (15h 04m 56.57s , +78d 49m 56.8s) |   C |    60 | 18.3 |        
   44877 | 2024-04-15 18:54:24 |      MASTER-Tavrida | (13h 21m 14.79s , +71d 15m 40.9s) |   C |    60 | 18.5 |        
   44950 | 2024-04-15 18:55:37 |   MASTER-Kislovodsk | (12h 55m 52.40s , +81d 11m 20.1s) |   C |    60 | 17.3 |        
   44950 | 2024-04-15 18:55:37 |   MASTER-Kislovodsk | (13h 21m 27.72s , +80d 44m 44.2s) |   C |    60 | 17.9 |        
   45031 | 2024-04-15 18:56:58 |   MASTER-Kislovodsk | (14h 51m 29.36s , +77d 21m 43.6s) |   C |    60 | 17.0 |        
   45031 | 2024-04-15 18:56:58 |   MASTER-Kislovodsk | (15h 09m 43.58s , +76d 54m 21.0s) |   C |    60 | 17.6 |        
   45111 | 2024-04-15 18:58:18 |   MASTER-Kislovodsk | (12h 23m 29.80s , +73d 37m 50.3s) |   C |    60 | 17.4 |        
   45111 | 2024-04-15 18:58:18 |   MASTER-Kislovodsk | (12h 38m 11.43s , +73d 13m 26.0s) |   C |    60 | 18.0 |        
   45165 | 2024-04-15 18:59:12 |      MASTER-Tavrida | (13h 46m 25.65s , +71d 16m 16.2s) |   C |    60 | 18.4 |        
   45191 | 2024-04-15 18:59:38 |   MASTER-Kislovodsk | (13h 57m 39.21s , +75d 28m 58.0s) |   C |    60 | 17.2 |        
   45191 | 2024-04-15 18:59:38 |   MASTER-Kislovodsk | (14h 13m 58.40s , +75d 03m 07.1s) |   C |    60 | 17.8 |        
   45240 | 2024-04-15 19:00:27 |      MASTER-Tavrida | (11h 42m 12.12s , +75d 01m 49.4s) |   C |    60 | 18.5 |        
   45271 | 2024-04-15 19:00:58 |   MASTER-Kislovodsk | (13h 22m 29.72s , +79d 18m 43.9s) |   C |    60 | 17.2 |        
   45271 | 2024-04-15 19:00:58 |   MASTER-Kislovodsk | (13h 44m 13.71s , +78d 52m 49.5s) |   C |    60 | 17.9 |        
   45317 | 2024-04-15 19:01:44 |      MASTER-Tavrida | (12h 13m 40.94s , +75d 01m 28.4s) |   C |    60 | 18.7 |        
   45351 | 2024-04-15 19:02:18 |   MASTER-Kislovodsk | (13h 16m 54.83s , +73d 36m 29.9s) |   C |    60 | 17.3 |        
   45351 | 2024-04-15 19:02:18 |   MASTER-Kislovodsk | (13h 31m 32.67s , +73d 11m 28.0s) |   C |    60 | 17.8 |        
   45388 | 2024-04-15 19:02:55 |      MASTER-Tavrida | (12h 33m 18.22s , +71d 13m 42.0s) |   C |    60 | 18.6 |        
   45432 | 2024-04-15 19:03:39 |   MASTER-Kislovodsk | (12h 32m 59.58s , +77d 25m 49.4s) |   C |    60 | 17.2 |        
   45432 | 2024-04-15 19:03:39 |   MASTER-Kislovodsk | (12h 51m 46.06s , +77d 01m 20.2s) |   C |    60 | 17.9 |        
   45460 | 2024-04-15 19:04:07 |      MASTER-Tavrida | (12h 58m 31.22s , +71d 15m 36.2s) |   C |    60 | 18.7 |        
   45512 | 2024-04-15 19:04:59 |   MASTER-Kislovodsk | (14h 21m 31.48s , +71d 41m 32.0s) |   C |    60 | 17.0 |        
   45512 | 2024-04-15 19:04:59 |   MASTER-Kislovodsk | (14h 34m 42.40s , +71d 16m 12.0s) |   C |    60 | 17.8 |        
   45533 | 2024-04-15 19:05:20 |      MASTER-Tavrida | (11h 41m 07.92s , +78d 48m 47.3s) |   C |    60 | 18.6 |        
   45593 | 2024-04-15 19:06:20 |   MASTER-Kislovodsk | (14h 43m 17.06s , +79d 15m 58.1s) |   C |    60 | 17.1 |        
   45593 | 2024-04-15 19:06:20 |   MASTER-Kislovodsk | (15h 04m 49.15s , +78d 49m 00.0s) |   C |    60 | 17.8 |        
   45605 | 2024-04-15 19:06:32 |      MASTER-Tavrida | (12h 23m 34.35s , +78d 51m 09.5s) |   C |    60 | 18.6 |        
   45673 | 2024-04-15 19:07:40 |   MASTER-Kislovodsk | (14h 57m 50.89s , +75d 27m 52.6s) |   C |    60 | 17.0 |        
   45753 | 2024-04-15 19:09:00 |   MASTER-Kislovodsk | (13h 47m 36.20s , +69d 49m 09.2s) |   C |    60 | 17.1 |        
   45753 | 2024-04-15 19:09:00 |   MASTER-Kislovodsk | (13h 59m 42.52s , +69d 24m 28.3s) |   C |    60 | 17.8 |        
   45833 | 2024-04-15 19:10:20 |   MASTER-Kislovodsk | (14h 59m 12.52s , +80d 42m 48.6s) |   C |    60 | 17.8 |        
   45894 | 2024-04-15 19:11:22 |      MASTER-Tavrida | (12h 42m 08.42s , +75d 03m 32.5s) |   C |    60 | 18.6 |        
   45966 | 2024-04-15 19:12:33 |      MASTER-Tavrida | (13h 13m 51.27s , +75d 02m 51.3s) |   C |    60 | 18.6 |

Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.

GCN Circular #36121
N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunko (ISTP), A. Moskvitin (SAO RAS), S. Belkin (IKI) report on behalf of GRB-IKI-FuN:
We report correction to the GCN 36118 (Pankov et al.) and additional photometry in subsequent epochs. Preliminary photometry of the optical transient is following:
```
Date       UT_start  MJD           Filter Exp.  OT    err  UL(3sigma)
                    (mid, days)           (s)
2024-04-15 14:33:22  60415.627345  R     30*120 19.9 0.1 21.8
2024-04-15 16:13:49  60415.697104  R     30*120 20.5 0.1 21.9
2024-04-15 17:20:02  60415.732668  R     15*120 20.9 0.1 21.9
```
The magnitudes were calibrated using nearby USNO-B1.0 stars.
GCN Circular #36122
A. Moskvitin, A. Vinokurov, A. Sarkisian (SAO RAS), N. Pankov (HSE, IKI), A. Pozanenko (IKI), report on behalf of GRB follow-up team.
We observed the field of the GRB 240415A (Fermi GBM team, GCN 36107; Moss et al., GCN 36108, Evans et al., GCN 36109) with the BTA, 6-m telescope of SAO RAS, equipped with the Scorpio-2 multi-mode focal reducer (Afanasiev & Moiseev, 2011, BaltA, 20, 363). We obtained series of 30 and 60 sec images in VRI bands on April 15, 17:38:12--18:05:08 UT.
The OT (Pankov et al., GCNs 36118; 36121) is clearly detected in the stacked frames of each band. Preliminary photometry of OT: R = 21.19 +/- 0.15 (17:39:08--18:03:53 UT, t_mid - T0 = 0.4754 days = 11.4104 hours). The magnitudes were calibrated using R2 magnitudes of nearby USNO-B1.0 stars.
GCN Circular #36123
A. Reguitti (INAF-OAB / INAF-OAPd), P. D'Avanzo (INAF-OAB), L. Tomasella (INAF -OAPd), E. Cappellaro (INAF -OAPd), report on behalf of the CIBO and of the GRAWITA collaborations:
We carried out follow-up optical observations of GRB 240415A (Fermi GBM Team, GCN Circ. #36107; Moss et al., GCN Circ. #36108) from the INAF - Padova Astronomical Observatory located in Asiago (Italy) with the 67/92 Schmidt telescope starting on 2024-04-15 at 19:13:10 UT (~ 12.8 hours after the burst) with the r-sdss filter.
In our stacked image the optical afterglow (Pankov et al., GCN Circ. #36118; Pankov et al., GCN Circ. #36121; Moskvitin et al., GCN Circ. #36122) is detected. From preliminary analysis we estimate a magnitude of r = 21.0 +/- 0.3 (AB; calibrated against r band of the PanSTARRS catalog).
Further observations are ongoing.
GCN Circular #36124
B. Schneider (MIT), C. Adami, O. Ilbert, N. A. Rakotondrainibe (LAM/Pythea= s/AMU), D. Turpin, E. Le Floc=E2=80=99h (CEA Paris-Saclay), A. Saccardi, S.= Vergani (GEPI/Obs. de Paris) report on behalf of a larger collaboration:
We observed the field of the GRB 240415A (Fermi GBM team, GCN 36107; Moss e= t al., GCN 36108; Evans et al., GCN 36109) and its afterglow candidate (Pan= kov et al., GCN 36118, GCN 36121; Moskvitin et al., GCN 36122; Reguitti et = al., GCN 36123) using the T193cm telescope at Observatoire de Haute-Provenc= e (France) equipped with the MISTRAL spectro-imager. A total of 6 exposures= (5x600s + 1x480s) were obtained in the r-band at 20:37:17.5 UT on 2024-04-= 15 (~14.1h after the trigger). In the combined frame, we clearly detect the= optical afterglow and measure the following preliminary magnitude:
r = 21.67 +/- 0.10 mag (AB)
The photometric calibration was performed using nearby stars from the PanST= ARRS catalog and the magnitude is not corrected for Galactic extinction.
We acknowledge the excellent support from Observatoire de Haute-Provence an= d in particular Jean Balcaen for the MISTRAL observations.
GCN Circular #36128
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 822 s of XRT Photon Counting mode data and 3 UVOT images for GRB 240415A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 129.18882, +73.14634 which is equivalent to:
```
RA (J2000): 08h 36m 45.32s
Dec (J2000): +73d 08' 46.8"
```
with an uncertainty of 2.8 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #36132
A. Aryan, T.-W. Chen, W.-J. Hou, H.-Y. Hsiao, C.-H. Lai, Y.-C. Pan (all NCUIA), S. Yang (HNAS), A. Sankar.K, M.-H. Lee, C.-S. Lin, C.-C. Ngeow, H.-C. Lin, J.-K. Guo (all NCUIA), H. F. Stevance, S. J. Smartt (Oxford/QUB), S. Srivastav (Oxford), M. Fulton, T. Moore, C. Angus, and A. Aamer (all QUB) report:
We observed the field of GRB 240415A (Fermi GBM team, GCN 36107; Moss et al., GCN 36108; Evans et al., GCN 36109) using the Lulin One-meter Telescope (LOT) at Lulin Observatory in Taiwan as part of the Kinder collaboration (Chen et al., AstroNote 2021-92). The optical afterglow candidate of GRB 240415A was identified (Pankov et al., GCN 36118, GCN 36121) and followed with several instruments (Lipunov et al., GCN 36119; Moskvitin et al., GCN 36122; Reguitti et al., GCN 36123, Schneider et al, GCN 36124).
The first LOT epoch of observations started at 13:17 UT on the 15th of April 2024. We followed the standard IRAF (Tody D., 1993, ASPC, 52, 173) procedure to reduce the images. Additionally, PSF photometry was performed using DAOPHOT II (Stetson P. B., 1987, PASP, 99, 191). The optical afterglow was clearly visible in the combined frame and was within the error box reported by Evans et al. (GCN 36128). The details of the observations and the preliminary magnitude (in the AB system) of the afterglow are as follows:
```
Telescope | Filter | MJD | t-t0 | Exposure | Magnitude | avg. Seeing | med. Airmass
LOT | r | 60415.554 | 6.86 hrs | 300 sec * 6 | 21.32 +/- 0.25 | 1".92 | 1.67
```
The reported magnitude is calibrated using 10 nearby stars from the PanSTARRS catalog and is not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V) = 0.02 mag in the direction of the burst (Schlafly & Finkbeiner 2011).
GCN Circular #36134
C. de Barra (UCD) and C. Meegan (UAH) report on behalf of the Fermi Gamma-r= ay Burst Monitor Team:
At 06:26:57.60 UT on 15 April 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240415A (trigger 734855222/240415269) which was a= lso detected by Swift BAT (M.J. Moss et al. 2024, GCN 36108).
The Fermi GBM on-ground location (Fermi GBM Team, GCN 36107) is consistent = with the Swift BAT position. The angle from the Fermi LAT boresight is 125.= 0 degrees
The GBM light curve contains a single emission episode with a duration (T90= ) of about 10 s (50-300 keV). The time-averaged spectrum from T0-4.1 to T0+6.1 s is best fit by is best fit by a Comptonized Epeak f= unction with Epeak =3D 42.10 +/- 5.26 keV, and alpha =3D -1.58 +/- 0.14
The event fluence (10-1000 keV) in this time interval is (1.8 +/- 0.1)E-06 = erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.58 s in th= e 10-1000 keV band is 7.7 +/- 0.3 ph/s/cm^2.=20
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 Pa= ge: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/
GCN Circular #36136
M. H. Siegel (PSU) and M. J. Moss (GSFC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 240415A 3309 s after the BAT trigger (Moss et al., GCN Circ. 36108). A source consistent with the XRT position (Beardmore et al., GCN Circ. 36128) and the reported optical transient (Pankov et al., GCN Circ. 36118, Moskvitin et al., GCN Circ. 36122, Reguitti et al., GCN Circ. 36123, Schneider et al., GCN Circ. 36124, Aryan et al., GCN Circ. 36132) is detected in the initial UVOT exposures.
Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white             3877         4077          197         19.92 +/- 0.19
v                 4287         4487          197         18.95 +/- 0.28
b                 3672         3872          197        >19.2
u                 3467         5040          332         18.96 +/- 0.18
w1                4698         4897          197        >19.3
m2                4492         4692          197        >19.1
w2                4083         4282          197        >19.5
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.022 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #36143
M. J. Moss (GSFC), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), T. Sakamoto (AGU) (i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 240415A (trigger #1221874) (Moss, et al., GCN Circ. 36108). The BAT ground-calculated position is RA, Dec = 129.197, 73.150 deg which is
```
   RA(J2000)  =  08h 36m 47.2s 
   Dec(J2000) = +73d 09' 01.7" 
```
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 60%.
The mask-weighted light curve displays a bright pulse lasting for ~15 s and peaking at ~T0+5 s and another dim pulse of emission at ~T0+30 s. The T90 (15-350 keV) is 30.96 +- 3.59 sec (estimated error including systematics).
The time-averaged spectrum from T-0.70 to T+37.50 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.28 +- 0.13. The fluence in the 15-150 keV band is 1.6 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+5.09 sec in the 15-150 keV band is 4.6 +- 0.4 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1221874
GCN Circular #36148
C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A.= Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
The Glowbug gamma-ray telescope [1,2], operating on the International Space= Station, reports the detection of GRB 240415A, which was also detected by = Fermi/GBM (GCN 36107, 36134) and Swift/BAT (GCN 36108, 36143).
Using an adaptive window with a resolution of 32-ms, the burst onset is det= ermined to be 2024-04-15 06:26:52.488 with a duration of 8.2 s and a total = significance of about 17.7 sigma. The light curve comprises two primary pe= aks at ~T0+1s and ~T0+4s.
The analysis results presented here are preliminary and use a response func= tion that lacks a detailed characterization of the surrounding passive stru= cture of the ISS. =20 Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost ga= mma-ray transient telescopes developed, built, and operated by the U.S. Nav= al Research Laboratory (NRL) with support from the University of Alabama in= Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard = the Department of Defense Space Test Program=E2=80=99s STP-H9 to the ISS. = The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering= the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length= ) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2= /3 sky) over a wide energy band of 50 keV to >2 MeV.
```
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
```
Distribution Statement A: Approved for public release. Distribution is unl= imited.
GCN Circular #36225
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
We have analysed 5.4 ks of XRT data for GRB 240415A, from 3.3 ks to 26.8 ks after the BAT trigger. The data comprise 281 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode.
The light curve can be modelled with a power-law decay with a decay index of alpha=0.97 (+/-0.09).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.18 (+/-0.16). The best-fitting absorption column is 2.2 (+/-0.5) x 10^21 cm^-2, in excess of the Galactic value of 2.5 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.3 x 10^-11 (4.9 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     2.2 (+/-0.5) x 10^21 cm^-2
Galactic foreground: 2.5 x 10^20 cm^-2
Excess significance: 6.4 sigma
Photon index:	     2.18 (+/-0.16)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01221874.
This circular is an official product of the Swift-XRT team.
GCN Circular #36381
Anshika Gupta (ARIES), Kuntal Misra (ARIES), Atul Kumar Singh (DDUGU) and Dimple (CMI) report:
We observed the field of GRB 240415A detected by Swift (GCN 36128 ) using the 1.3m Devasthal Fast Optical Telescope (DFOT) located at the Devasthal observatory of Aryabhatta Research Institute of observational sciencES (ARIES), Nainital, India. The observation started on 2024-04-16 at 15:29:51 UTC. Multiple frames of 300 sec exposure were acquired in the R band. We do not detect the optical afterglow (earlier reported in GCN 36122, GCN 36123, GCN 36124, GCN 36132) in the stacked image down to a limiting magnitude of 21.8. The photometric calibration is performed using the standard stars from the USNO-B1.0 catalog.

Back to JG's homepage

Jochen Greiner, last update: 03-May-2024 [Disclaimer]