Glossary
========

.. glossary::

    BBH
        Binary black hole system, a binary system composed of two black holes.

    BNS
        Binary neutron star, a binary system composed of two neutron stars.

    CBC
        Compact binary coalescence.

    FITS
        Flexible Image Transport System, a format for astronomical tables,
        images, and multidimensional data sets.

    LHO
        LIGO Hanford Observatory (see `LHO observatory home page
        <https://www.ligo.caltech.edu/LA>`_), site of a 4 km gravitational-wave
        detector in Hanford, Washington, USA.

    LLO
        LIGO Livingston Observatory (see `LLO observatory home page
        <https://www.ligo.caltech.edu/WA>`_), site of a 4 km gravitational-wave
        detector in Livingston, Louisiana, USA.

    GCN
        The Gamma-ray Coordinates Network (https://gcn.gsfc.nasa.gov), a portal
        for discoveries and observations of astronomical transients.
        Historically, GCN has served high-energy satellites but now also other
        electromagnetic wavelengths and also gravitational-wave, cosmic ray,
        and neutrino facilities.

    GCN Circular
        A human-readable astronomical bulletin distributed through :term:`GCN`.

    GCN Notice
        A machine-readable alert distributed through :term:`GCN`.

    GraceDb
        Gravitational Wave Candidate Event Database (https://gracedb.ligo.org),
        the official public marshal portal for LIGO/Virgo candidates.

    HEALPix
        Hierarchical Equal Area isoLatitude Pixelation, a scheme for indexing
        positions on the unit sphere.

    NSBH
        Neutron star black hole, a binary system composed of one neutron star
        and one black hole.

    Virgo
        Virgo Observatory (see `Virgo observatory home page
        <http://www.virgo-gw.eu>`_), site of a 3 km gravitational-wave detector
        in Cascina, Italy.

    VOEvent
        An XML format for describing astronomical transients. For the
        specification, see the official `VOEvent IVOA Recommendation
        <http://www.ivoa.net/documents/VOEvent/index.html>`_.

    VTP
        VOEvent Transport Protocol, a simple TCP-based protocol for sending and
        receiving VOEvents, used by :term:`GCN`. For the specification, see the
        official `VTP IVOA recommendation
        <http://www.ivoa.net/documents/Notes/VOEventTransport/>`_.