The properties of the Magellanic Bridge based on OGLE IV RR Lyrae variables

作者：Wagner Kaiser R; Sarajedini Ata

来源：Monthly Notices of the Royal Astronomical Society, 2017, 466(4): 4138-4146.

DOI：10.1093/mnras/stw3206

• stars: variables: RR Lyrae
• galaxies: evolution
• galaxies: formation
• galaxies: interactions
• Magellanic Clouds

We examine the properties of the Magellanic Bridge connecting the Large and Small Magellanic Clouds using ab-type RR Lyrae variables from the extensive data set of the Optical Gravitational Lensing Experiment (OGLE), Phase IV data release. The metallicities of the RR Lyraes are determined from the characteristics of their light curves, with an average abundance of [Fe/H] = -1.790 +/- 0.011 (sem) in the Magellanic Bridge. From the individual reddenings of these stars, derived via their minimum light-curve colours, we determined a median colour excess of E(V - I) = 0.101 +/- 0.007 (sem) [implying E(B - V) approximate to 0.077]. The peak distance modulus of 18.57 +/- 0.048 (sem) places the Bridge stars at distances between the two systems. The metallicity and distance distributions probe the structure of the Magellanic system as a whole, revealing a smooth transition that connects the galaxies. An examination of the HI content does not find a clear correlation between HI emission strength and RR Lyrae spatial distribution, suggesting that the old stellar populations may trace the overlapping halo distributions of the two Magellanic Clouds.

• 出版日期2017-5