A New Deep HST/ACS CMD of I Zw 18: Evidence for Red Giant Branch Stars

Details A New Deep HST/ACS CMD of I Zw 18: Evidence for Red Giant Branch Stars A New Deep HST/ACS CMD of I Zw 18: Evidence for Red Giant Branch Stars

2007-02-07

arxiv.org/abs/astro-ph/0702216v2

Astronomy and Astrophysics

Astrophysics

4 pages, 2 figures. Typos corrected. Proceedings of the IAU Symp. 241 "Stellar Populations as Building Blocks of Galaxies", he

Scientific paper

10.1017/S1743921307008228

We present results from new deep HST/ACS photometry of I Zw 18, the most metal-poor blue compact dwarf galaxy in the nearby universe. It has been previously argued that this is a very young system that started forming stars only < 500 Myr ago, but other work has hinted that older (> 1 Gyr) red giant branch (RGB) stars may exist in this galaxy. Our deeper data indeed reveal evidence for an RGB. Underlying old (> 1 Gyr) populations are therefore present in even the most metal-poor systems, implying that star formation started at z > 0.1. The RGB tip (TRGB) magnitude and the properties of Cepheid variables identified from our program indicate that I Zw 18 is farther away (D = 19.0 +/- 1.8 Mpc) than previously believed.

Affiliated with

Also associated with

No associations

Rating

A New Deep HST/ACS CMD of I Zw 18: Evidence for Red Giant Branch Stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A New Deep HST/ACS CMD of I Zw 18: Evidence for Red Giant Branch Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A New Deep HST/ACS CMD of I Zw 18: Evidence for Red Giant Branch Stars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-431972