Papers
Topics
Authors
Recent
Gemini 2.5 Flash
Gemini 2.5 Flash
134 tokens/sec
GPT-4o
10 tokens/sec
Gemini 2.5 Pro Pro
47 tokens/sec
o3 Pro
4 tokens/sec
GPT-4.1 Pro
38 tokens/sec
DeepSeek R1 via Azure Pro
28 tokens/sec
2000 character limit reached

A 10,000 star spectroscopic survey of the thick disk-halo interface : Phase-space sub-structure in the thick disk (1302.4913v1)

Published 20 Feb 2013 in astro-ph.GA

Abstract: We analyse a 10,000 star spectroscopic survey, focused on Galactic thick disk stars typically 2-5 kpc from the Sun, carried out using the AAOmega Spectrograph on the AAT. We develop methods for completeness-correction of the survey based on SDSS photometry, and we derive star distances using an improved isochrone-fitting method with accuracies better than 10%. We determine the large-scale kinematic (Vphi=172 km/s and sigma(phi,r,z) = (49,51,40) km/s), and abundance properties of the thick disk, showing these representative values are a fair description within about 3 kpc of the sun, and in the range 1-3 kpc from the Galactic Plane. We identify a substantial overdensity in lines of sight towards the inner Galaxy, with metallicity [Fe/H] -1 dex, and higher line of sight velocities than the thick disk, localised along the direction (l,b)=(48,-26). This overdensity appears to be towards, but closer than, the known Hercules-Aquila halo overdensity and may be related to the Humphreys-Larsen inner galaxy thick disk asymmetry.

Summary

We haven't generated a summary for this paper yet.