Access to Astronomical Catalogues

← Click to display the menu
J/ApJ/682/1029          Abundances in OGLE-2007-BLG-349S          (Cohen+, 2008)

Clues to the metallicity distribution in the galactic bulge: abundances in OGLE-2007-BLG-349S. Cohen J.G., Huang W., Udalski A., Gould A., Johnson J.A. <Astrophys. J., 682, 1029-1040 (2008)> =2008ApJ...682.1029C
ADC_Keywords: Abundances ; Equivalent widths ; Gravitational lensing ; Stars, dwarfs Keywords: galaxies: bulges - Galaxy: bulge - gravitational lensing - stars: abundances Abstract: We present an abundance analysis based on high-dispersion and high signal-to-noise ratio Keck spectra of a very highly microlensed Galactic bulge dwarf, OGLE-2007-BLG-349S, with Teff∼5400K. The amplification at the time the spectra were taken ranged from 350 to 450. This bulge star is highly enhanced in metallicity with [Fe/H]=+0.51±0.09dex. The abundance ratios for the 28 species of 26 elements for which features could be detected in the spectra are almost all solar. In particular, there is no evidence for enhancement of any of the α-elements, including O and Mg. We conclude that the high [Fe/H] seen in this star, when combined with the equally high [Fe/H] derived in previous detailed abundance analysis of two other Galactic bulge dwarfs, both also highly magnified by microlensing, implies that the median metallicity in the Galactic bulge is very high. We thus infer that many previous estimates of the metallicity distribution in the Galactic bulge have substantially underestimated the mean Fe metallicity there due to sample bias, and suggest a candidate mechanism for such. If our conjecture proves valid, it may be necessary to update the calibrations for the algorithms used by many groups to interpret spectra and broadband photometry of the integrated light of very metal-rich old stellar populations, including luminous elliptical galaxies. Description: We took three consecutive spectra, each 1350s in length with the HIRES-R on the Keck I telescope in the night of 2007 September 5. Objects: ---------------------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------------------- 18 05 24.4 -26 25 19 EWS 2007-BLG-349 = MOA 2007-BLG-379 ---------------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 38 249 Equivalent widths for OGLE-2007-BLG-349S
See also: J/A+A/512/A41 : Abundances of microlensed stars in the Bulge (Bensby+, 2010) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 7 F7.2 0.1nm lambda Wavelength (Å) 9- 13 A5 --- Ion Species identification 15- 18 F4.2 eV ExPot Excitation potential 20- 25 F6.3 [-] log(gf) Log of the oscillator strength 27 A1 --- n_log(gf) [a] inverted solar analysis used to determine gf 29- 30 A2 --- l_EW [≤ ] Limit flag on EqWid 32- 36 F5.1 10-13m EW ? Equivalent width in milli-Angstroms 38 A1 --- n_EW [s] Synthesis used to derive EqWid
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 24-Nov-2010
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

catalogue service