• Leo Pound Singer's avatar
    Document integer OBJECT fields in bayestar-localize-coincs · 6dd6a5e1
    Leo Pound Singer authored
    The script `bayestar-localize-coincs` saves FITS files with
    integer-valued `OBJECT` cards in their FITS headers. This is
    somewhat unusual, because the `OBJECT` card is usually a string
    used to give the designation of an astronomical object (such as
    `M83` or `Feige 55`). The `OBJECT` cards saved by
    `bayestar-localize-coincs`, on the other hand, are integers that
    refer to a coinc_event table row in the input LIGO-LW file. Add
    an explanation to the `bayestar-localize-coincs` command-line
    help message and also to the `COMMENT` in the FITS header.
    
    Here is an example FITS headere generated by
    `bayestar-localize-coincs`:
    
    ```
    SIMPLE  =                    T / conforms to FITS standard
    BITPIX  =                    8 / array data type
    NAXIS   =                    0 / number of array dimensions
    EXTEND  =                    T
    
    XTENSION= 'BINTABLE'           / binary table extension
    BITPIX  =                    8 / array data type
    NAXIS   =                    2 / number of array dimensions
    NAXIS1  =                   40 / length of dimension 1
    NAXIS2  =                19200 / length of dimension 2
    PCOUNT  =                    0 / number of group parameters
    GCOUNT  =                    1 / number of groups
    TFIELDS =                    5 / number of table fields
    TTYPE1  = 'UNIQ    '
    TFORM1  = 'K       '
    TTYPE2  = 'PROBDENSITY'
    TFORM2  = 'D       '
    TUNIT2  = 'sr-1    '
    TTYPE3  = 'DISTMU  '
    TFORM3  = 'D       '
    TUNIT3  = 'Mpc     '
    TTYPE4  = 'DISTSIGMA'
    TFORM4  = 'D       '
    TUNIT4  = 'Mpc     '
    TTYPE5  = 'DISTNORM'
    TFORM5  = 'D       '
    TUNIT5  = 'Mpc-2   '
    PIXTYPE = 'HEALPIX '           / HEALPIX pixelisation
    ORDERING= 'NUNIQ   '           / Pixel ordering scheme: RING, NESTED, or NUNIQ
    COORDSYS= 'C       '           / Ecliptic, Galactic or Celestial (equatorial)
    MOCORDER=                    9 / MOC resolution (best order)
    INDXSCHM= 'EXPLICIT'           / Indexing: IMPLICIT or EXPLICIT
    OBJECT  =                    0 / Unique identifier for this event
    INSTRUME= 'H1,L1,V1'           / Instruments that triggered this event
    DATE-OBS= '2012-07-17T22:13:12.220679' / UTC date of the observation
    MJD-OBS =    56125.92583588749 / modified Julian date of the observation
    DATE    = '2020-09-25T17:26:49.000000' / UTC date of file creation
    CREATOR = 'BAYESTAR'           / Program that created this file
    ORIGIN  = 'LIGO/Virgo'         / Organization responsible for this FITS file
    RUNTIME =         53.403897459 / Runtime in seconds of the CREATOR program
    DISTMEAN=     299.256659137929 / Posterior mean distance (Mpc)
    DISTSTD =    92.05707284960283 / Posterior standard deviation of distance (Mpc)
    LOGBCI  =    4.326877727439793 / Log Bayes factor: coherent vs. incoherent
    LOGBSN  =    7.485118470191388 / Log Bayes factor: signal vs. noise
    VCSVERS = 'ligo.skymap 0.5.1.dev5+g5fa79380.d20200925' / Software version
    HISTORY
    HISTORY Generated by calling the following Python function:
    HISTORY ligo.skymap.bayestar.localize(event=..., waveform='o2-uberbank', f_low=3
    HISTORY 0, min_inclination=0.0, max_inclination=1.5707963267948966, min_distance
    HISTORY =None, max_distance=None, prior_distance_power=2, cosmology=False, mcmc=
    HISTORY False, chain_dump=None, enable_snr_series=True, f_high_truncate=0.95)
    HISTORY
    HISTORY This was the command line that started the program:
    HISTORY bayestar-localize-coincs runs/O3/bns_astro/events.xml.gz --coinc-event-i
    HISTORY d 0 -o /tmp
    COMMENT
    COMMENT The integer value in the OBJECT card in this FITS header is a row ID
    COMMENT that refers to a coinc_event table row in the input LIGO-LW document.
    COMMENT
    ```
    6dd6a5e1
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CHANGES.rst 31.4 KB