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Mass Distribution in Sloan Digital Sky Survey

Mass Distribution in Sloan Digital Sky Survey

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Mass Distribution in Sloan Digital Sky Survey

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  1. Mass Distribution in Sloan Digital Sky Survey Kepler Scot Kleinman, Atsuko Nitta Detlev Koester, Bárbara Castanheira Leandro Althaus, Daniel Eisenstein, Odilon Giovannini

  2. 1859 DAs DR4 513 DR1 303 PG DR1: Madej J., Nalezyty M., Althaus L.G., 2004, A&A, 419, L5 PG: Liebert J., Bergeron P., Holberg J.B., 2005, ApJS, 156, 47

  3. Why g<19? SNR>20 Gemini 8m SDSS

  4. 7753 DAs in DR4, 348 in Liebert et al. 2005 PG

  5. Monte Carlo simulation for SNR=20

  6. 964 DAs

  7. DA DB PG 7753 DAs, 616 DBs in DR4

  8. 243 DBs g<19

  9. High Mass DA 3230 Das with g<19, 864 (27%) have M>0.8 Mo,, 13 above 1.2Mo and Teff > 12000K

  10. High Mass DA

  11. Low Mass DAs Mo Mo

  12. Is the increase in mass at low Teff real? -Convection bringing He up? MH<10-11M*? NO! Seismology MH>10-7 alsoLawlor & McDonald 2006 models -Neutral particles treatment? NO! Piotr Kowalski, 2006, astro-ph0607606 -Low metallicity in AGB? WD 1Mo Lee Ann Wilson, 2000, ARA&A, 38, 573 Falk Herwig, 2004, ApJS, 155, 651 Albert Zijlstra, 2004, MNRAS, 348, L23 DA Age12000K ~0.4 Gyr for 0.6 Mo ~2 Gyr for 1.2 Mo DB Age15000K ~0.3 Gyr for 0.6 Mo ~1.1Gyr for 1.2 Mo -New Theory? Neutral particle broadening? DB DA

  13. D. Koester – LPT fit to Gemini spectra – Massive DA candidates Star Teff dTeff log g dlog g SDSS auto29 Mass(Msun) WD0747+4527 14803 102 8.712 0.016 1.043 0.009 13541 149 8.77 0.03 1.073 0.017 g=17.40 WD0759+4335 17913 172 9.860 0.013 1.359 0.001 21913 419 9.51 0.07 1.314 0.012 g=18.73 WD2309+0112 30017 26 8.707 0.006 1.054 0.003 30601 186 8.48 0.03 0.937 0.015 g=16.57 WD0326-0011 32652 76 8.858 0.015 1.105 0.007 33202 131 8.59 0.03 0.997 0.017 g=17.65