I/341               PMA Catalogue                            (Akhmetov+, 2017)
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The PMA Catalogue: 420 million positions and absolute proper motions.
    Akhmetov V.S., Fedorov P.N., Velichko A.B., Shulga V.M.
    <Mon. Not. R. Astron. Soc. 469, 763 (2017)>
    =2017MNRAS.469..763A        (SIMBAD/NED BibCode)
    =2017yCat.1341....0A
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ADC_Keywords: Positional data ; Proper motions
Keywords: catalogues - astrometry - proper motions - reference systems -
          Galaxy: kinematics and dynamics

Abstract:
    We present a catalogue that contains about 420 million absolute proper
    motions of stars. It was derived from the combination of positions
    from Gaia DR1 and 2MASS, with a mean difference of epochs of about
    15yr. Most of the systematic zonal errors inherent in the 2MASS
    Catalogue were eliminated before deriving the absolute proper motions.
    The absolute calibration procedure (zero-pointing of the proper
    motions) was carried out using about 1.6 million positions of
    extragalactic sources. The mean formal error of the absolute
    calibration is less than 0.35mas/yr. The derived proper motions cover
    the whole celestial sphere without gaps for a range of stellar
    magnitudes from 8 to 21mag. In the sky areas where the extragalactic
    sources are invisible (the avoidance zone), a dedicated procedure was
    used that transforms the relative proper motions into absolute ones.
    The rms error of proper motions depends on stellar magnitude and
    ranges from 2-5mas/yr for stars with 10mag<G<17mag to 5-10mas/yr for
    faint ones. The present catalogue contains the Gaia DR1 positions of
    stars for the J2015 epoch. The system of the PMA proper motions does
    not depend on the systematic errors of the 2MASS positions, and in the
    range from 14 to 21mag represents an independent realization of a
    quasi-inertial reference frame in the optical and near-infrared
    wavelength range. The Catalogue also contains stellar magnitudes taken
    from the Gaia DR1 and 2MASS catalogues. A comparison of the PMA proper
    motions of stars with similar data from certain recent catalogues has
    been undertaken.

Description:
    The idea for creating the catalogue is very simple. The PMA catalogue
    has been derived from a combination of two catalogues, namely 2MASS
    and Gaia DR1. The difference of epochs of observations for these
    catalogues is approximately 15 yr. The positions of objects in the
    Gaia DR1 catalogue are referred to the reference frame, which is
    consistent with ICRF to better than 0.1 mas for the J2015.0 epoch. The
    positions of objects in 2MASS are referred to HCRF, which, as was
    shown in Kovalevsky et al. (1997A&A...323..620K), is aligned with the
    ICRF to within +/-0.6 mas at the epoch 1991.25 and is non-rotating
    with respect to distant extragalactic objects to within +/-0.25mas/yr.
    By comparing the positions of the common objects contained in the
    catalogues, it is possible to determine their proper motions within
    their common range of stellar magnitudes by dividing differences of
    positions over the time interval between their observations. Formally,
    proper motions derived in such a way are given in the ICRF system,
    because the positions of both Gaia DR1 stars and those of 2MASS
    objects (through Hipparcos/Tycho-2 stars) are given in the ICRF and
    cover the whole sphere without gaps. We designate them further in this
    paper as relative, with the aim of discriminating them from absolute
    ones, which refer to the reference frame defined by the positions of
    about 1.6 million galaxies from Gaia DR1.

    After elimination of the systematic errors, the root-mean-squared
    deviation of the coordinate differences of extended sources is about
    200mas, and the mean number of galaxies inside each pixel is about
    1300, so we expect the error of the absolute calibration to be
    0.35mas/yr.

    We compared the proper motions of common objects from PMA and from the
    TGAS and UCAC4 catalogues. Knowing the mean-square errors of
    (PMA-TGAS) and (PMA-UCAC4) proper motion differences in each
    pixel, the appropriate errors in PMA vary from 2 to 10mas/yr,
    depending on magnitude, which are consistent with the errors
    calculated above.

    In case of any problems or questions, please contact by e-mail
    V.S. Akhmetov (akhmetovvs(at)gmail.com or akhmetov(at)astron.kharkov.ua).

File Summary:
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 FileName      Lrecl  Records   Explanations
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ReadMe            80        .   This file
pma/*              .      360  *PMA Catalogue (421454398 sources)
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Note on pma/*: pma???.dat (pma000.dat to pma359.dat) ascii PMA catalog,
  organized by declination zones of 30' and sort by right ascension.
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See also:
   I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
  II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
   I/337 : Gaia DR1 (Gaia Collaboration, 2016)
   I/339 : Hot Stuff for One Year (HSOY) (Altmann+, 2017)
   I/340 : UCAC5 Catalogue (Zacharias+ 2017)

Byte-by-byte Description of file: pma/*
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   Bytes Format  Units     Label   Explanations
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   1- 14  F14.10 deg       RAdeg   Right ascension (ICRS, epoch 2015.0)
                                    from GAIA DR1 (RA)
  16- 29  F14.10 deg       DEdeg   Declination (ICRS, epoch 2015.0)
                                    from GAIA DR1 (DEC)
  31- 35  F5.2   mas     e_RAdeg   Standard error of right ascension
                                    from GAIA DR1 (eRA)
  37- 41  F5.2   mas     e_DEdeg   Standard error of declination
                                    from GAIA DR1 (eDEC)
  43- 49  F7.2   mas/yr    pmRA    Proper motion in right ascension
                                    (pmRAcosDE) (pmRA)
  51- 57  F7.2   mas/yr    pmDE    Proper motion in declination (pmDE)
  59- 63  F5.2   mas/yr  e_pmRA    Standard error of proper motion in
                                    right ascension (e_pmRA)
  65- 69  F5.2   mas/yr  e_pmDE    Standard error of proper motion in
                                    declination (e_pmDE)
  71- 76  F6.3   mag       Gmag    G-band mean magnitude from GAIA DR1 (Gmag)
  78- 83  F6.3   mag       Jmag    J magnitude from 2MASS (j_mag)
  85- 89  F5.3   mag     e_Jmag    Standard error in J magnitude  (er_jmag)
  91- 96  F6.3   mag       Hmag    H magnitude from 2MASS (h_mag)
  98-102  F5.3   mag     e_Hmag    Standard error in J magnitude (re_hmag)
 104-109  F6.3   mag       Kmag    Ks magnitude from 2MASS (k_mag)
 111-115  F5.3   mag     e_Kmag    Standard error in J magnitude (er_kmang)
 117-126  A10    ---       Cntr    Unique source identifier in 2MASS (pts_key)
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Acknowledgements:
    V. S. Akhmetov, akhmetovvs(at)gmail.com or akhmetov(at)astron.kharkov.ua

History:
    * 04-Jul-2017: First version
    * 20-Sep-2017: errors on proper motions added (from author)

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(End)                                      Patricia Vannier [CDS]    28-Jun-2017