The Recent Evolution of the Dwarf Starburst Galaxy NGC 625 from Hubble Space Telescope Imaging
نویسندگان
چکیده
New HST/WFPC2 imaging of the dwarf starburst galaxy NGC625 is presented. These data, which are 80% complete to V and I magnitudes of 26.0 and 25.3 respectively, allow us to study the recent star formation history of NGC625. Using outlying red giants stars, we derive a tip of the red giant branch (TRGB) distance modulus of 27.95±0.07. This corresponds to a distance of 3.89±0.22 Mpc, placing this system on the far side of the Sculptor Group. NGC625 has a well-defined radial stellar population gradient, evidenced by a central concentration of young main sequence stars and an RGB/AGB ratio that increases with galactocentric distance. The prominent AGB is very red, similar to the population found in the Local Group dIrr NGC6822. The RGB stars
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