A Subaru/Suprime-Cam Survey of M31's spheroid along the South-East minor axis

Mikito Tanaka; Masashi Chiba; Yutaka Komiyama; Masanori Iye; Puragra Guhathakurta

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arXiv · 0704.3328

A Subaru/Suprime-Cam Survey of M31's spheroid along the South-East minor axis

Mikito Tanaka·Masashi Chiba·Yutaka Komiyama·Masanori Iye·Puragra Guhathakurta

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Abstract

We have used Suprime-Cam on the Subaru Telescope to conduct a V- and I-band imaging survey of fields sampling the spheroid of the Andromeda galaxy along its south-east minor axis. Our photometric data are deep enough to resolve stars down to the red clump. Based on a large and reliable sample of red giant stars available from this deep wide-field imager, we have derived metallicity distributions vs. radius and a surface brightness profile over projected distances of R=23-66 kpc from the galaxy's center. The metallicity distributions across this region shows a clear high mean metallicity and a broad distribution ([Fe/H] ~ -0.6 +/- 0.5), and indicates no metallicity gradient within our observed range. The surface brightness profile at R>40 kpc is found to be flatter than previously thought. It is conceivable that this part of the halo samples as yet unidentified, metal-rich substructure.

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Mikito Tanaka, Masashi Chiba, Yutaka Komiyama, Masanori Iye, Puragra Guhathakurta. 2007-04-25. A Subaru/Suprime-Cam Survey of M31's spheroid along the South-East minor axis. https://arxiv.org/abs/0704.3328

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