Extremely metal-poor stars in SDSS fields
نویسندگان
چکیده
1 GEPI, Observatoire de Paris, CNRS, Université Paris Diderot, Place Jules Janssen, 92190 Meudon, France 2 Zentrum für Astronomie der Universität Heidelberg, Landessternwarte, Königstuhl 12, 69117 Heidelberg, Germany 3 Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching, Germany 4 Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Trieste, Via Tiepolo 11, 34143 Trieste, Italy 5 Université de Nice Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur, Laboratoire Cassiopé e, B.P. 4229, 06304 Nice Cedex 4, France 6 Istituto Nazionale di Astrofisica, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy 7 Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy 8 Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova Vicolo dell’Osservatorio 5, 35122 Padova, Italy
منابع مشابه
Searches for the Most Metal-Poor Candidates from SDSS and SEGUE
We report on efforts to identify large samples of very and extremely metal-poor stars based on medium-resolution spectroscopy and ugriz photometry obtained during the course of the Sloan Digital Sky Survey (SDSS), and its extension, SDSS-II, which includes the program SEGUE: Sloan Extension for Galactic Understanding and Exploration. To date, over 8000 stars with [Fe/H] ≤ −2.0 and effective tem...
متن کامل¿¿ Ñóðð Blockinùððö Ððòò Óöññøøóò Ò Ûöö Ööóò¹¹òòòò Ññøøð¹ôóóö ×øøö×
We present a detailed analysis of the carbon and nitrogen abundances of two dwarf carbon-enhanced metal-poor (CEMP) stars: SDSS J1349-0229 and SDSS J0912+0216. We also report the oxygen abundance of SDSS J1349-0229. These stars are metal-poor, with [Fe/H] < –2.5, and were selected from our ongoing survey of extremely metal-poor dwarf candidates from the Sloan Digital Sky Survey (SDSS). The carb...
متن کاملSdss 0809+1729: Connections between Extremely Metal Poor Galaxies and Gamma Ray Burst Hosts
We discuss the serendipitous discovery of an extremely metal poor galaxy, SDSS 0809+1729, classified as a star in the Sloan Digital Sky Survey (SDSS). The galaxy has a redshift z = 0.0441 and a B-band absolute magnitude MB = −17.1. With a metallicity of log(O/H) + 12∼ 7.44 or ∼ 1/20 solar, this galaxy is among the 10 most metal poor emission-line galaxies known. SDSS 0809+1729 is a blue compact...
متن کاملThe minimum stellar metallicity observable in the Galaxy
The first stars fundamentally transformed the early Universe through their production of energetic radiation and the first heavy chemical elements. The impact on cosmic evolution sensitively depends on their initial mass function (IMF), which can be empirically constrained through detailed studies of ancient, metal-poor halo stars in our Galaxy. We compare the lowest magnesium and iron abundanc...
متن کاملFinding the Most Metal-poor Stars of the Galactic Halo with the Hamburg/ESO Objective-prism Survey
I review the status of the search for extremely metal-poor halo stars with the Hamburg/ESO objective-prism survey (HES). 2 194 candidate metal-poor turnoff stars and 6 133 giants in the magnitude range 14 . B . 17.5 have been selected from 329 (out of 380) HES fields, covering an effective area of 6 400 square degrees in the southern extragalactic sky. Moderate-resolution followup observations ...
متن کاملThe chemical composition of metal - poor emission - line galaxies in the Data Release 3 of the Sloan Digital Sky Survey ⋆
We have re-evaluated empirical expressions for the abundance determination of N, O, Ne, S, Cl, Ar and Fe taking into account the latest atomic data and constructing an appropriate grid of photoionization models with state-of-the art model atmospheres. Using these expressions we have derived heavy element abundances in the ∼ 310 emission-line galaxies from the Data Release 3 of the Sloan Digital...
متن کامل