OGLE small-amplitude variables in the Galactic bar
نویسندگان
چکیده
منابع مشابه
OGLE small amplitude red giant variables in the Galactic Bar
Among over 200,000 Galactic Bulge variable stars in the public domain OGLE catalogue, we found over 15,000 red giant variables following two well defined period – amplitude relations. The periods are in the range 10 < P < 100 days, and amplitudes in the range 0.005 < A < 0.13 mag in I-band. The variables cover a broad range of reddening corrected colours, 1 < (V − I)0 < 5, and a fairly narrow r...
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The analysis of the first two years of OGLE data revealed 9 microlensing events of the galactic bulge stars, with the characteristic time scales in the range 8.6 < t0 < 62 days, where t0 = RE/V . The optical depth to microlensing is larger than (3.3 ± 1.2) × 10, in excess of current theoretical estimates, indicating a much higher efficiency for microlensing by either bulge or disk lenses. We ar...
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Red clump giant stars can be used as distance indicators to trace the mass distribution of the Galactic bar. We use RCG stars from 44 bulge fields from the OGLE-II microlensing collaboration database to constrain analytic tri-axial models for the Galactic bar. We find the bar major axis is oriented at an angle of 24◦ – 27◦ to the Sun-Galactic centre line-of-sight. The ratio of semi-major and se...
متن کاملThe Galactic Bar
The Milky Way has a barred bulge. This article summarizes the current understanding of the main structural parameters and pattern speed of the bar, and compares predicted values for the microlensing optical depth with the bulge microlensing observations.
متن کاملMira Variables in the OGLE Bulge fields ⋆
The 222 000 I-band light curves of variable stars detected by the OGLE-II survey in the direction of the Galactic Bulge have been fitted and have also been correlated with the DENIS and 2MASS all-sky release databases and with lists of known objects. Lightcurves, and the results of the lightcurve fitting (periods and amplitudes) and DENIS and 2MASS data are presented for 2691 objects with I-ban...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 2004
ISSN: 0035-8711,1365-2966
DOI: 10.1111/j.1365-2966.2004.07587.x