Abstract
We present evidence for a substantial overdensity of stars in the direction of the constellations of Hercules and Aquila. The cloud is centered at a Galactic longitude of l ≈ 40° and extends above and below the Galactic plane by at least 50°. Given its off-centeredness and height, it is unlikely that the Hercules-Aquila cloud is related to the bulge or thick disk. More likely, this is a new structural component of the Galaxy that passes through the disk. The cloud stretches ∼80° in longitude. Its heliocentric distance lies between 10 and 20 kpc so that the extent of the cloud in projection is ∼20 kpc by ∼15 kpc. It has an absolute magnitude of Mv = -13, and its stellar population appears to be comparable to, but somewhat more metal-rich than, M92.
Original language | English |
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Pages (from-to) | L89-L92 |
Number of pages | 4 |
Journal | Astrophysical Journal |
Volume | 657 |
Issue number | 2 |
DOIs | |
Publication status | Published - 10 Mar 2007 |
Externally published | Yes |