PRELIMINARY PARSEC's Proper Motion Catalog for 195701 southern stars ================================================================================ from: Parallaxes of Southern Extremely Cool objects - I: Targets, Proper motions and first results. A.H. Andrei(1,2,3), R.L. Smart(2), J.L. Penna(1), V. A. d'Avila(1,4), B. Bucciarelli(2), J.I.B. Camargo(1), M. T. Crosta(2), M. Dapra(2), B. Goldman(5), H.R.A. Jones(6), M.G. Lattanzi(2), L.Nicastro(7), D.N. da Silva Neto(8) and R. Teixeira(9) (1) ON/MCT; (2) OATo/INAF; (3) OV/UFRJ; (4) UERJ; (5) Max Planck; (6) U. of Hertfordshire; (7) IASFC/INAF; (8) UEZO/RJ; (9) IAG/USP ================================================================================ Description: The proper motion determination was made from a match to the 2MASS point source catalogue. In principle, the program frames should be complete with respect to 2MASS and the epoch difference is small, so a nearest neighbor match was sufficient to not mismatch high proper motion objects. As a safety measure, the proper motions were determined for each observation combination and later averaged. Deviant values were removed from these averages, as they either came from unrecognised frame defects or faulty measurements. A more robust algorithm is being developed using the GSC2.3 positions at different epochs. While the parallax determination of the targets uses only the upper third of CCD7, the reduction pipeline is applied to the entire mosaic of 8 CCDs. From these data we have constructed the proper motion catalogue, which samples the whole of the southern hemisphere with the exception of the lowest galactic latitudes where the number of known L/T dwarfs is significantly reduced. This catalog contains proper motion determinations for 195,701 objects. For its construction we determine an astrometric reduction relative to the Second US Naval Observatory CCD Astrograph Catalog (UCAC2, Zacharias et al. 2004), independently for each CCD and each observation. . The average number of reference stars was 20, with which polynomial functions were adjusted on right ascension and declination. Depending on the number of reference stars the polynomial degree was 2 or 3 and cross terms were or not be included. Abstract of the original paper: We present results from the PARallaxes of Southern Extremely Cool objects (PARSEC) program, an observational program begun in April 2007 to determine parallaxes for 122 L and 28 T southern hemisphere dwarfs using the ESO 2.2m telescope Wide Field Imager. The results presented here include parallaxes of 10 targets from observations over 18 months and a first version proper motion catalog. The proper motions were obtained by combining PARSEC observations astrometrically reduced with respect to the Second US Naval Observatory CCD Astrograph Catalog, and the Two Micron All Sky Survey Point Source Catalogue. The resulting median proper motion precision is 5mas/yr for 195,700 sources. The 140 0.3deg2 fields sample the southern hemisphere in an unbiased fashion with the exception of the galactic plane due to the small number of targets in that region. The proper motion distributions are shown to be statistically well behaved. External comparisons are also fully consistent. We will continue to update this catalog until the end of the program and we plan to improve it including also observations from the GSC2.3 database. We present preliminary parallaxes with a 4.2 mas median precision for 10 brown dwarfs, 2 of which are within 10pc. Those increase increase by 11% the present number of L dwarfs with published values. Of the 10 targets, 7 have been previously discussed in the literature: two were thought to be binary but the PARSEC observations show them to be single, one has been confirmed as a binary companion and another has been found to be part of a binary system, both of which will make good benchmark systems. These results confirm that the foreseen precision of PARSEC can be achieved and that the large field of view will allow us to identify wide binary systems. Observations for the PARSEC program will end in early 2011 providing on average 3 years of coverage for all targets. The main expected outputs are: more than a 100% increase of the number of L dwarfs with parallaxes; to increment - in conjuction with published results - to at least 10 the number of objects per spectral subclass up to L9, and; to put sensible limits on the general binary fraction of brown dwarfs. We aim to contribute significantly to the understanding of the faint end of the H-R diagram and of the L/T transition region. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe_pmcat . This file TABLE_final.trgt 117 195701 Proper motions (and associated data) -------------------------------------------------------------------------------- Byte-by-byte Description of file: TABLE_final.trgt -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 2- 12 F11.7 deg RA Right ascension (J2000.0) 14- 18 F5.1 mas e_RAs RA error (RAcosDE) 20- 30 F11.7 deg DE Declination (J2000.0) 32- 36 F5.1 mas e_DEs DE error 38- 41 F4.2 --- zmag z Magnitude (instrumental) 43- 44 I2 --- Nobs Number of observations (2007-2008) 46- 53 F8.4 year MEpc Mean epoch of observation 55- 61 F7.1 mas/y PMra Proper motion in right ascension (x cosDE) 63- 68 F6.1 mas/y e_PMra PMra error 70- 76 F7.1 mas/y PMde Proper motion in declination 78- 83 F6.1 mas/y e_PMra PMde error 85- 89 F5.2 year DT Time interval for PM calculation 91- 94 F4.1 --- Hmag J magnitude from the 2MASS catalog 96- 99 F4.1 --- Hmag H magnitude from the 2MASS catalog 101-104 F4.1 --- Hmag K magnitude from the 2MASS catalog 106-113 A8 --- Name Pseudo-name of the field (target+RA+DEC) 115-115 A1 --- CCD WFI CCD of the observation (ESO WFI numbering) 117-117 A1 --- TAR "T" code to mark up the target (see abstract) -------------------------------------------------------------------------------- Note (1): Data from Andrei et al., 2010, AJ. Note (2): The above data represent the preliminary, working proper motion solution. Note (3): Comments and queries may be addressed to Alexandre Andrei (oat1@on.br) --------------------------------------------------------------------------------