Astrophysics and Space Science

, Volume 335, Issue 1, pp 161–169 | Cite as

GALEX catalogs of UV sources: statistical properties and sample science applications: hot white dwarfs in the Milky Way

  • L. BianchiEmail author
  • J. Herald
  • B. Efremova
  • L. Girardi
  • A. Zabot
  • P. Marigo
  • A. Conti
  • B. Shiao
Open Access
Original Article


We describe the content and properties of UV source catalogs from GALEX’s All-Sky Imaging Survey (AIS, 5σ depth ≈19.9(FUV)/20.8(NUV) mag, in the AB system) and Medium-depth Imaging Survey (MIS, 5σ depth ≈22.6(FUV)/22.7(NUV) mag), constructed by Bianchi L., et al.: Mon. Not. R. Astron. Soc. (2010, in press). The catalogs contain 65.3/12.6 million (AIS/MIS) unique UV sources with photometric error in NUV less than 0.5 mag, over 21 435(AIS)/1579(MIS) square degrees. Matched optical data from GSC-II provide additional B, R, I photometry for the brightest sources, and SDSS provides u g r i z photometry over 7325(AIS)/1103(MIS) square degrees overlap areas. We discuss statistical properties that are relevant for understanding sample selection biases and completeness, in potential science applications of these catalogs. The FUV (1344–1786 Å) and NUV (1771–2831 Å) photometry uniquely enable selection of the hottest stellar objects, in particular hot white dwarfs (WD), which are elusive at optical wavelengths because of their hot temperatures and faint luminosities. From the GALEX-SDSS matched sources we selected ∼40 000 Milky Way (MW) stars hotter than about 18 000 K (FUV-NUV < −0.13). Their density increases towards low Galactic latitudes, but drops in the MW disk due to dust extinction. The hot-WD density at different Galactic latitudes, analyzed with Milky Way models, constrains the Initial-Final Mass Relation (IFMR), relevant for understanding the yield of chemical elements from intermediate-mass stars and the chemical enrichment of the Galaxy.


Astronomical Data Bases: catalogues Stars: white dwarfs Stars: evolution Galaxy: stellar content Ultraviolet: stars Galaxies: Milky Way 


  1. Bianchi, L., et al.: Mon. Not. R. Astron. Soc. (2010), doi: 10.1111/j.1365-2966.2010.17890.x
  2. Bianchi, L.: Astrophys. Space Sci. 320, 11 (2009) ADSCrossRefGoogle Scholar
  3. Bianchi, L., et al.: Astron. J. 137, 3761 (2009a) ADSCrossRefGoogle Scholar
  4. Bianchi, L., Efremova, B., Herald, J., et al.: In: Van Steenberg et al. (eds.) Future Directions in Ultraviolet Spectroscopy. AIPC, vol. 1135, p. 326 (2009b) Google Scholar
  5. Bianchi, L.: In: Gomez de Castro, A., Barstow, M. (eds.) UV Astronomy: Stars from Birth to Death, p. 65 (2007). ISBN 978-84-7491-852-6 Google Scholar
  6. Bianchi, L., et al.: Astrophys. J. Suppl. Ser. 173, 659 (2007) ADSCrossRefGoogle Scholar
  7. Bianchi, L., et al.: Astrophys. J. 619, L27 (2005) ADSCrossRefGoogle Scholar
  8. Bianchi, L.: (2011), this book Google Scholar
  9. Conti, A., Bianchi, L., Shiao, B., et al.: (2011), this book Google Scholar
  10. Girardi, L., et al.: Astron. Astrophys. 436, 895 (2005) ADSCrossRefGoogle Scholar
  11. Hutchings, J., Bianchi, L.: Astron. J. 140, 1987 (2010) ADSCrossRefGoogle Scholar
  12. Lasker, B., et al.: Astron. J. 136, 735 (2008) ADSCrossRefGoogle Scholar
  13. Marigo, P., Girardi, L.: Astron. Astrophys. 469, 239 (2007) ADSCrossRefGoogle Scholar
  14. Martin, D.C., et al.: Astrophys. J. Lett. 619, L1 (2005) ADSCrossRefGoogle Scholar
  15. McCandliss, S.R., et al.: Proc. SPIE 4, 5488–6117 (2005) Google Scholar
  16. Morrissey, et al.: Astrophys. J. Suppl. Ser. 173, 682 (2007) ADSCrossRefGoogle Scholar
  17. Schlegel, D.J., et al.: Astrophys. J. 500, 525 (1998) ADSCrossRefGoogle Scholar
  18. Shustov, B., Sachkov, M., Gomez de Castro, A.I., et al.: Astrophys. Space Sci. 320, 187 (2009) ADSCrossRefGoogle Scholar
  19. Weidemann, V.: Astron. Astrophys. 363, 647 (2000) ADSGoogle Scholar

Copyright information

© The Author(s) 2011

Authors and Affiliations

  • L. Bianchi
    • 1
    Email author
  • J. Herald
    • 1
  • B. Efremova
    • 1
  • L. Girardi
    • 2
  • A. Zabot
    • 3
  • P. Marigo
    • 4
  • A. Conti
    • 5
  • B. Shiao
    • 5
  1. 1.Department of Physics & AstronomyJohns Hopkins UniversityBaltimoreUSA
  2. 2.INAF-Padua ObservatoryPaduaItaly
  3. 3.Universidade Federal da Fronteira SulSanta CatarinaBrazil
  4. 4.Department of AstronomyPadua UniversityPaduaItaly
  5. 5.Space Telescope Science InstituteBaltimoreUSA

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