PROPER MOTIONS IN THE GALACTIC BULGE: PLAUT'S WINDOW
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| Format: | Artículo científico |
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Universidad Nacional Autónoma de México
2009
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| _version_ | 1876426950324518912 |
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| author | K. Vieira |
| author_facet | K. Vieira |
| contents | PROPER MOTIONS IN THE GALACTIC BULGE: PLAUT'S WINDOW K. Vieira D. I. Casetti-Dinescu R. A. Méndez R. M. Rich T. M. Girard V. I. Korchagin W. F. van Altena S. R. Majewski S. van den Bergh Física, Astronomía y Matemáticas Catalogs Astrometry Galaxy: disk Galaxy: bulge stars: kinematics A proper motion study of a eld of 20' x20' inside Plaut's low extinction window (l,b)=(0°;-8°), has been completed. Relative proper motions and photographic BV photometry have been derived for -21; 000 stars reaching to V - 20:5 mag, based on the astrometric reduction of 43 photographic plates, spanning over 21 years of epoch di erence. Proper motion errors are typically 1 mas yr-1. Cross-referencing with the 2MASS catalog yielded a sample of - 8700 stars, from which predominantly disk and bulge subsamples were selected photometrically from the JH color-magnitude diagram. The two samples exhibited di erent proper-motion distributions, with the disk displaying the expected re ex solar motion. Galactic rotation was also detected for stars between -2 and -3 kpc from us. The bulge sample, represented by red giants, has an intrinsic proper motion dispersion of (l; b) = (3:39; 2:91) = (0:11; 0:09) mas yr-1, which is in good agreement with previous results. A mean distance of 6:37+0:87 -0:77 kpc has been estimated for the bulge sample, based on the observed K magnitude of the horizontal branch red clump. The metallicity [M=H] distribution was also obtained for a subsample of 60 bulge giants stars, based on calibrated photometric indices. The observed [M=H] shows a peak value at [M=H]-0:1 with an extended metal poor tail and around 30% of the stars with supersolar metallicity. No change in proper motion dispersion was observed as a function of [M=H]. We are currently in the process of obtaining CCD UBV RI photometry for the entire proper-motion sample of - 21; 000 stars. 2009 artículo científico 0185-1101 https://www.redalyc.org/articulo.oa?id=57115758049 es http://www.redalyc.org/revista.oa?id=571 Revista Mexicana de Astronomía y Astrofísica application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Astronomía y Astrofísica (México) Vol.35 |
| format | Artículo científico |
| id | redalyc_57115758049 |
| institution | Redalyc |
| language | es |
| publishDate | 2009 |
| publisher | Universidad Nacional Autónoma de México |
| spellingShingle | PROPER MOTIONS IN THE GALACTIC BULGE: PLAUT'S WINDOW K. Vieira Física, Astronomía y Matemáticas Catalogs Astrometry Galaxy: disk Galaxy: bulge stars: kinematics PROPER MOTIONS IN THE GALACTIC BULGE: PLAUT'S WINDOW K. Vieira D. I. Casetti-Dinescu R. A. Méndez R. M. Rich T. M. Girard V. I. Korchagin W. F. van Altena S. R. Majewski S. van den Bergh Física, Astronomía y Matemáticas Catalogs Astrometry Galaxy: disk Galaxy: bulge stars: kinematics A proper motion study of a eld of 20' x20' inside Plaut's low extinction window (l,b)=(0°;-8°), has been completed. Relative proper motions and photographic BV photometry have been derived for -21; 000 stars reaching to V - 20:5 mag, based on the astrometric reduction of 43 photographic plates, spanning over 21 years of epoch di erence. Proper motion errors are typically 1 mas yr-1. Cross-referencing with the 2MASS catalog yielded a sample of - 8700 stars, from which predominantly disk and bulge subsamples were selected photometrically from the JH color-magnitude diagram. The two samples exhibited di erent proper-motion distributions, with the disk displaying the expected re ex solar motion. Galactic rotation was also detected for stars between -2 and -3 kpc from us. The bulge sample, represented by red giants, has an intrinsic proper motion dispersion of (l; b) = (3:39; 2:91) = (0:11; 0:09) mas yr-1, which is in good agreement with previous results. A mean distance of 6:37+0:87 -0:77 kpc has been estimated for the bulge sample, based on the observed K magnitude of the horizontal branch red clump. The metallicity [M=H] distribution was also obtained for a subsample of 60 bulge giants stars, based on calibrated photometric indices. The observed [M=H] shows a peak value at [M=H]-0:1 with an extended metal poor tail and around 30% of the stars with supersolar metallicity. No change in proper motion dispersion was observed as a function of [M=H]. We are currently in the process of obtaining CCD UBV RI photometry for the entire proper-motion sample of - 21; 000 stars. 2009 artículo científico 0185-1101 https://www.redalyc.org/articulo.oa?id=57115758049 es http://www.redalyc.org/revista.oa?id=571 Revista Mexicana de Astronomía y Astrofísica application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Astronomía y Astrofísica (México) Vol.35 |
| title | PROPER MOTIONS IN THE GALACTIC BULGE: PLAUT'S WINDOW |
| topic | Física, Astronomía y Matemáticas Catalogs Astrometry Galaxy: disk Galaxy: bulge stars: kinematics |
| url | https://www.redalyc.org/articulo.oa?id=57115758049 |