PROBING THE OUTER GALACTIC HALO WITH RR LYRAE FROM THE CATALINA SURVEYS
| Autor: | A. J. Drake, M. Catelan, S. G. Djorgovski, G. Torrealba, M. J. Graham, V. Belokurov, S. E. Koposov, A. Mahabal, J. L. Prieto, C. Donalek, R. Williams, S. Larson, E. Christensen, E. Beshore |
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| Rok vydání: | 2013 |
| Předmět: |
Physics
010308 nuclear & particles physics media_common.quotation_subject Milky Way Metallicity FOS: Physical sciences Astronomy and Astrophysics Astrophysics RR Lyrae variable Astrophysics - Astrophysics of Galaxies 01 natural sciences Galactic halo Stars Space and Planetary Science Sky Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences 010303 astronomy & astrophysics Data release Sagittarius media_common |
| Zdroj: | ASTROPHYSICAL JOURNAL Artículos CONICYT CONICYT Chile instacron:CONICYT |
| ISSN: | 1538-4357 0004-637X |
| DOI: | 10.1088/0004-637x/763/1/32 |
| Popis: | We present the analysis of 12227 type-ab RR Lyrae found among the 200 million public lightcurves in the Catalina Surveys Data Release 1 (CSDR1). These stars span the largest volume of the Milky Way ever surveyed with RR Lyrae, covering ~20,000 square degrees of the sky (0 < RA < 360, -22 < Dec < 65 deg) to heliocentric distances of up to 60kpc. Each of the RR Lyrae are observed between 60 and 419 times over a six-year period. Using period finding and Fourier fitting techniques we determine periods and apparent magnitudes for each source. We find that the periods at generally accurate to sigma = 0.002% by comparison with 2842 previously known RR Lyrae and 100 RR Lyrae observed in overlapping survey fields. We photometrically calibrate the light curves using 445 Landolt standard stars and show that the resulting magnitudes are accurate to ~0.05 mags using SDSS data for ~1000 blue horizontal branch stars and 7788 of the RR Lyrae. By combining Catalina photometry with SDSS spectroscopy, we analyze the radial velocity and metallicity distributions for > 1500 of the RR Lyrae. Using the accurate distances derived for the RR Lyrae, we show the paths of the Sagittarius tidal streams crossing the sky at heliocentric distances from 20 to 60 kpc. By selecting samples of Galactic halo RR Lyrae, we compare their velocity, metallicity, and distance with predictions from a recent detailed N-body model of the Sagittarius system. We find that there are some significant differences between the distances and structures predicted and our observations. 28 pages, 29 figures, accepted ApJ |
| Databáze: | OpenAIRE |
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