| Title | The inner halo of M 87: a first direct view of the red-giant population |
| Authors | Bird, S.; Harris, W. E.; Blakeslee, J. P.; Flynn, C. |
| Bibcode | 2010A&A...524A..71B Search ADS ↗ |
| Abstract | An unusually deep (V, I) imaging dataset for the Virgo supergiant M 87 with the Hubble Space Telescope ACS successfully resolves its brightest red-giant stars, reaching MI(lim) = -2.5. After assessing the photometric completeness and biasses, we use this material to estimate the metallicity distribution for the inner halo of M 87, finding that the distribution is very broad and likely to peak near [m/H] ≃ -0.4 and perhaps higher. The shape of the MDF strongly resembles that of the inner halo for the nearby giant E galaxy NGC 5128. As a byproduct of our study, we also obtain a preliminary measurement of the distance to M 87 with the TRGB (red-giant branch tip) method; the result is (m-M)0 = 31.12 ± 0.14 (d = 16.7 ± 0.9 Mpc). Averaging this result with three other recent techniques give a weighted mean d(M 87) = (16.4 ± 0.5) Mpc. |
| Objects | 3 Objects Search NED ↙ |
