TDRSS lightcurve for Trigger=1073821

Notes:

GCN BAT Position Notice

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 18 Sep 21 07:59:35 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1073821,   Seg_Num: 0
GRB_RA:          250.455d {+16h 41m 49s} (J2000),
                 250.850d {+16h 43m 24s} (current),
                 249.548d {+16h 38m 12s} (1950)
GRB_DEC:         -45.540d {-45d 32' 22"} (J2000),
                 -45.580d {-45d 34' 46"} (current),
                 -45.444d {-45d 26' 39"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=1368 [image_cnts]
TRIGGER_DUR:     64.000 [sec] 
TRIGGER_INDEX:   20000     E_range: 15-50 keV
BKG_INTEN:       0 [cnts]
BKG_TIME:        0.00 SOD {00:00:00.00} UT
BKG_DUR:         0 [sec]
GRB_DATE:        19475 TJD;   261 DOY;   21/09/18
GRB_TIME:        28700.25 SOD {07:58:20.25} UT
GRB_PHI:         -139.31 [deg]
GRB_THETA:        22.35 [deg]
SOLN_STATUS:     0x19D
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    6.79 [sigma]
MERIT_PARAMS:     +0  +0 +123  +6  +1  -3  +0  +1 -16  +0 
SUN_POSTN:       175.99d {+11h 43m 58s}   +1.74d {+01d 44' 07"}
SUN_DIST:         80.73 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      327.10d {+21h 48m 23s}  -18.54d {-18d 32' 22"}
MOON_DIST:        67.37 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      339.19,  0.49 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      255.24,-23.10 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is an image trigger.  (The RATE_SIGNIF & BKG_{INTEN, TIME, DUR} are undefined.)  
COMMENTS:        A point_source was found.  
COMMENTS:        This matches a source in the on-board catalog: Num=10632=IGR16418-4532,   delta=0.008 [deg].  
COMMENTS:        This matches a source in the ground catalog: IGRJ16418-4532,   delta=0.003 [deg].  
COMMENTS:        This is not a GRB.  
COMMENTS:        This is an interesting source.  
COMMENTS:        Since the IMAGE_SIGNIF is less than 7 sigma, this is a questionable detection.  
COMMENTS:        This trigger occurred at longitude,latitude = 177.80,-17.51 [deg].  

GCN BAT Lightcurve Notice

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 18 Sep 21 08:16:15 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1073821,   Seg_Num: 0
GRB_RA:          250.455d {+16h 41m 49s} (J2000),
                 250.850d {+16h 43m 24s} (current),
                 249.548d {+16h 38m 12s} (1950)
GRB_DEC:         -45.540d {-45d 32' 22"} (J2000),
                 -45.580d {-45d 34' 46"} (current),
                 -45.444d {-45d 26' 39"} (1950)
GRB_DATE:        19475 TJD;   261 DOY;   21/09/18
GRB_TIME:        28700.25 SOD {07:58:20.25} UT
TRIGGER_INDEX:   20000
GRB_PHI:         -139.31 [deg]
GRB_THETA:        22.35 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     64.000 [sec] 
SOLN_STATUS:     0x19D
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    6.79 [sigma]
LC_URL:          sw01073821000msb.lc

GCN template for BAT paragraph

  • Click here!
    At 07:58:20 UT, the Swift Burst Alert Telescope (BAT) triggered and
    located GRB 210918 ***A*** (trigger=1073821).  Swift slewed immediately to the burst.
    The BAT on-board calculated location is 
    RA, Dec 250.455, -45.540 which is 
       RA(J2000) = 16h 41m 49s
       Dec(J2000) = -45d 32' 22"
    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 ~1265 counts/sec (15-350 keV), at ~0 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 background rate 1:     4601.886 near MET 653644808.960000 s
      Estimated background rate 2:     4601.886 near MET 653644808.960000 s
      Estimated total fluence: 0.000000 count
      Created GTI with 1 entries
    ------------------------------------------
     
    

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

    bat_grb_pos_cat.sh 250.455 -45.540 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 250.455 -45.540
    IGR J16418-4532 10632 250.463 -45.542 0.005947585014473103
    

    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: 2021 9 18 8 235.650103  -32.635922
     Obj: 2021 9 18 8 63.753146  -66.491347
    
  • the object visibility at GSFC, Greenbelt, Maryland
     
    MMT Observatory, Mt. Hopkins, Arizona
          TimeUT       Azimuth     Elevation
     Sun: 2021 9 18 8 197.888604  -55.256011
     Obj: 2021 9 18 8 54.534906  -39.013590
    
  • the object visibility at MMT, Mt. Hopkins, Arizona
     
    Hale Telescope, Palomar Mountain, California
          TimeUT       Azimuth     Elevation
     Sun: 2021 9 18 8 187.119127  -54.721440
     Obj: 2021 9 18 8 54.593469  -35.867123
    
  • the object visibility at Hale Telescope, Palomar Mt., California
     
    Mauna Kea, Hawaii
          TimeUT       Azimuth     Elevation
     Sun: 2021 9 18 8 118.552328  -49.903305
     Obj: 2021 9 18 8 41.345267  -1.427234
    
  • the object visibility at Mauna Kea, Hawaii
     
    Siding Spring Obs., Australia
          TimeUT       Azimuth     Elevation
     Sun: 2021 9 18 8 91.459505  -0.972405
     Obj: 2021 9 18 8 35.238916  71.456414
    
  • the object visibility at Siding Spring Obs., Australia
     
    Tokyo, Japan
          TimeUT       Azimuth     Elevation
     Sun: 2021 9 18 8 81.911509  14.581209
     Obj: 2021 9 18 8 358.985735  9.970441
    
  • the object visibility at Tokyo, Japan
     
    William Herschel Telescope, La Palma, Canary Islands, Spain
          TimeUT       Azimuth     Elevation
     Sun: 2021 9 18 8 274.837539  12.265206
     Obj: 2021 9 18 8 314.860341  -62.163896
    
  • the object visibility at William Hershel Telescope, La Palma, Canary Islands, Spain
     
    Gemini South, Cerro Pachon, Chile
          TimeUT       Azimuth     Elevation
     Sun: 2021 9 18 8 291.297350  -34.772530
     Obj: 2021 9 18 8 17.430880  -10.834736
    
  • the object visibility at Gemini South, Cerro Pachon, Chile
     
     
     
    The data/results are in /local/data/bat1/prebascript/trigger1073821/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 18 04:17:25 EDT 2021