TDRSS lightcurve for Trigger=1351008

Notes:

GCN BAT Position Notice

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 20 Sep 25 08:46:49 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1351008,   Seg_Num: 0
GRB_RA:          187.337d {+12h 29m 21s} (J2000),
                 187.646d {+12h 30m 35s} (current),
                 186.734d {+12h 26m 56s} (1950)
GRB_DEC:         +47.844d {+47d 50' 39"} (J2000),
                 +47.702d {+47d 42' 08"} (current),
                 +48.120d {+48d 07' 13"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       4653 [cnts]    Image_Peak=547 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   148     E_range: 25-100 keV
BKG_INTEN:       14781 [cnts]
BKG_TIME:        31571.63 SOD {08:46:11.63} UT
BKG_DUR:         8 [sec]
GRB_DATE:        20938 TJD;   263 DOY;   25/09/20
GRB_TIME:        31590.58 SOD {08:46:30.58} UT
GRB_PHI:         -72.75 [deg]
GRB_THETA:        26.34 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     62.35 [sigma]
IMAGE_SIGNIF:    17.87 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +5  +0  +0 -67  +0 
SUN_POSTN:       177.84d {+11h 51m 22s}   +0.93d {+00d 56' 04"}
SUN_DIST:         47.54 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      162.47d {+10h 49m 52s}   +8.13d {+08d 07' 39"}
MOON_DIST:        44.97 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:      133.24, 68.84 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      162.00, 45.58 [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:        This trigger occurred at longitude,latitude = 101.23,5.35 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(4.0<100sec) coincident with the FERMI_GBM event (trignum=780050791).

GCN BAT Lightcurve Notice

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 20 Sep 25 09:03:51 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1351008,   Seg_Num: 0
GRB_RA:          187.337d {+12h 29m 21s} (J2000),
                 187.646d {+12h 30m 35s} (current),
                 186.734d {+12h 26m 56s} (1950)
GRB_DEC:         +47.844d {+47d 50' 39"} (J2000),
                 +47.702d {+47d 42' 08"} (current),
                 +48.120d {+48d 07' 13"} (1950)
GRB_DATE:        20938 TJD;   263 DOY;   25/09/20
GRB_TIME:        31590.58 SOD {08:46:30.58} UT
TRIGGER_INDEX:   148
GRB_PHI:         -72.75 [deg]
GRB_THETA:        26.34 [deg]
DELTA_TIME:      26.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     62.35 [sigma]
IMAGE_SIGNIF:    17.87 [sigma]
LC_URL:          sw01351008000msb.lc

GCN template for BAT paragraph

  • Click here! 
    At 08:46:30 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 250920 ***A*** (trigger=1351008).  Swift slewed immediately to the burst.
The BAT on-board calculated location is 
RA, Dec 187.337, +47.844 which is 
   RA(J2000) = 12h 29m 21s
   Dec(J2000) = +47d 50' 39"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a [**double-peaked**]
structure with a duration of about TTT sec.  The peak count rate
was ~8199 counts/sec (15-350 keV), at ~5 sec after the trigger.
  • Test version of draft template

    Initial TDRSS lightcurve and spacecraft attitude plot

    TDRSS lightcurve from T0-30 to T0+50 (zoom in)

    TDRSS light curve from T0-1 to T0+2 (More zoom in)

    1.6s binned TDRSS light curve

    Tilan's background subtracted TDRSS light curves

    Extended TDRSS light curve and spacecraft attitude plot(s)

    Extended TDRSS lc No.1

    Extended TDRSS lc No.2

    Extended TDRSS lc No.3

    TDRSS extended lightcurve from T0-1 to T0+2

    T50 and T90 calculation

    ******************************************
         battblocks v1.18
------------------------------------------
     Input Data: bat_raw_lc.fits
     Output GTI: bb.gti
 Events to Skip: 128     Changepoint log(prob) Prior: 6.000000
  Internal Tick: 1.000000e-04 s
  Lookback time: 0 s
 Bkg. Subtract?: yes (for fluence/T50/T90 calculations)
------------------------------------------
  Estimated T90 duration: 124.8 s +/- 2.89772 s
  Estimated T50 duration: 61.44 s +/- 4.096 s
  Estimated Peak Interval: MET   780050900.47999990 +/- 0.500000 s
  Estimated background rate 1:     3531.469 near MET 780050812.320000 s
  Estimated background rate 2:     3494.800 near MET 780050992.640000 s
  Estimated total duration: 150.72 s (for data selection)
       (from MET 780050821.440000 to MET 780050972.160000)
  Estimated total fluence: 144007.212606 count
  Created GTI with 44 entries
------------------------------------------

    Search for this GRB position to the previously BAT detected GRB positions (search radius within 5 arcmin)

    bat_grb_pos_cat.sh 187.337 47.844 0.083
No match

    Search for this GRB position to the source locations in BAT transient monitor (search radius within 12 arcmin)

    python compare_catalog.py 187.337 47.844
No match

    Link to SIMBAD

  • Click here for the SIMBAD search!

    Frank's UVOT result

  • Click here!

    Frank's UVOT Blinking images

  • Click here!

    Elevation angle of GRB/Sun at the ground telescope locations

    GSFC, Greenbelt, Maryland
      TimeUT       Azimuth     Elevation
 Sun: 2025 9 20 9 248.759139  -22.787388
 Obj: 2025 9 20 9 211.046445  7.188811
  • the object visibility at GSFC, Greenbelt, Maryland 
     
MMT Observatory, Mt. Hopkins, Arizona
      TimeUT       Azimuth     Elevation
 Sun: 2025 9 20 9 221.139962  -49.563080
 Obj: 2025 9 20 9 190.494364  -9.437981
  • the object visibility at MMT, Mt. Hopkins, Arizona 
     
Hale Telescope, Palomar Mountain, California
      TimeUT       Azimuth     Elevation
 Sun: 2025 9 20 9 211.820027  -51.226232
 Obj: 2025 9 20 9 186.450284  -8.533820
  • the object visibility at Hale Telescope, Palomar Mt., California 
     
Mauna Kea, Hawaii
      TimeUT       Azimuth     Elevation
 Sun: 2025 9 20 9 135.417512  -61.920197
 Obj: 2025 9 20 9 159.920840  -17.623677
  • the object visibility at Mauna Kea, Hawaii 
     
Siding Spring Obs., Australia
      TimeUT       Azimuth     Elevation
 Sun: 2025 9 20 9 82.762510  -13.499178
 Obj: 2025 9 20 9 131.798757  -26.047371
  • the object visibility at Siding Spring Obs., Australia 
     
Tokyo, Japan
      TimeUT       Azimuth     Elevation
 Sun: 2025 9 20 9 89.980802  1.635350
 Obj: 2025 9 20 9 129.100305  31.676270
  • the object visibility at Tokyo, Japan 
     
William Herschel Telescope, La Palma, Canary Islands, Spain
      TimeUT       Azimuth     Elevation
 Sun: 2025 9 20 9 283.637366  24.994675
 Obj: 2025 9 20 9 229.464434  32.848969
  • the object visibility at William Hershel Telescope, La Palma, Canary Islands, Spain 
     
Gemini South, Cerro Pachon, Chile
      TimeUT       Azimuth     Elevation
 Sun: 2025 9 20 9 282.309867  -21.779241
 Obj: 2025 9 20 9 231.201495  -44.736092
  • the object visibility at Gemini South, Cerro Pachon, Chile 
     
 
 
The data/results are in /local/data/bat1/prebascript/trigger1351008/tdrss_ql/
 
bat_raw_lc.fits  : TDRSS FITS light curve from GCN
gcn_position.txt : GCN BAT position notice
ratelc_tdrss.qdp : QDP file of the TDRSS light curve
tdrss_lc.gif     : GIF TDRSS light curve
sc_att.qdp       : QDP file of the spacecraft attitude
sc_att.gif       : GIF spacecraft attitude
bb.gti           : Bayesian block GTI file (battblocks)
dur.gti          : Duration GTI file (battblocks)
battblocks.log   : Output log of battblocks
 


    Plot creation:
Sat Sep 20 05:05:03 EDT 2025