A PUZZLE INVOLVING GALACTIC BULGE MICROLENSING EVENTS

Journal Article · Mon Mar 01 00:00:00 EST 2010 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/711/1/L48; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21305123

Cohen, Judith G ^[1]; Gould, Andrew; Johnson, Jennifer A ^[2]; Thompson, Ian B ^[3]; Feltzing, Sofia ^[4]; Bensby, Thomas ^[5]; Wenjin, Huang ^[6]; Melendez, Jorge ^[7]; Lucatello, Sara ^[8]; Asplund, Martin ^[9]

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1. Palomar Observatory, Mail Stop 249-17, California Institute of Technology, Pasadena, CA 91125 (United States)
2. Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States)
3. Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
4. Lund Observatory, Box 43, SE-22100 Lund (Sweden)
5. European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago 19 (Chile)
6. Palomar Observatory, Mail Stop 105-24, California Institute of Technology, Pasadena, CA 91125 (United States)
7. Centro de Astrofisica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal)
8. INAF-Astronomical Observatory of Padova, Vicolo dell'Osservatorio 5, 35122 Padova (Italy)
9. Max Planck Institute for Astrophysics, Postfach 1317, 85741 Garching (Germany)

We study a sample of 16 microlensed Galactic bulge main-sequence turnoff region stars for which high-dispersion spectra have been obtained with detailed abundance analyses. We demonstrate that there is a very strong and highly statistically significant correlation between the maximum magnification of the microlensed bulge star and the value of the [Fe/H] deduced from the high resolution spectrum of each object. Physics demands that this correlation, assuming it to be real, be the result of some sample bias. We suggest several possible explanations, but are forced to reject them all, and are left puzzled. To obtain a reliable metallicity distribution in the Galactic bulge based on microlensed dwarf stars, it will be necessary to resolve this issue through the course of additional observations.

• OSTI ID: 21305123
• Journal Information: Astrophysical Journal Letters, Vol. 711, Issue 1; Other Information: DOI: 10.1088/2041-8205/711/1/L48; Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
ABUNDANCE
CORRELATIONS
DWARF STARS
GALAXIES
SPECTRA