We present the results of a detailed optical and near-IR study of the nearby star-forming dwarf galaxy NGC 4214 .
We discuss the stellar content , drawing particular attention to the intermediate-age and/or old field stars , which are used as a distance indicator .
On images obtained with the Hubble Space Telescope WFPC2 and NICMOS instruments in the equivalents of the V , R , I , J and H bands , the galaxy is well resolved into stars .
We achieve limiting magnitudes of F 814 W \approx 27 in the WF chips and F 110 W \approx 25 in the NIC2 .
The optical and near-infrared color-magnitude diagrams confirm a core-halo galaxy morphology : an inner high surface-brightness young population within \sim 1 \farcm 5 ( \sim 1 kpc ) from the center of the galaxy , where the stars are concentrated in bright complexes along a bar-like structure ; and a relatively low-surface-brightness , field-star population extending out to at least 8 \arcmin ( 7 kpc ) .
The color-magnitude diagrams of the core region show evidence of blue and red supergiants , main-sequence stars , asymptotic giant branch stars and blue loop stars .
We identify some candidate carbon stars from their extreme near-IR color .
The field-star population is dominated by the “ red tangle ” , which contains the red giant branch .
We use the I -band luminosity function to determine the distance based on the tip-of-the-red-giant-branch method : 2.7 \pm 0.3 Mpc .
This is much closer than the values usually assumed in the literature , and we provide revised distance dependent parameters such as physical size , luminosity , H i mass and star-formation rate .
From the mean color of the red giant branch in V and I , we estimate the mean metal abundance of this population as [ Fe/H ] \simeq - 1.7 dex , with a large internal abundance spread characterized by \sigma _ { int } ( { [ Fe / H ] } ) \approx 1 dex .