Comparison between the Globular Clusters in Ngc 5128 and the Galaxy Globular
نویسنده
چکیده
Some of the properties of the globular clusters in NGC 5128 the nearest giant elliptical galaxy are compared to those of Galactic globular clusters. Assuming the colormetallicity relations that hold for Galactic globular clusters one finds that the metal-poor clusters in NGC 5128 that have [Fe/H] < -1.80 are significantly fainter than are the more metal-rich globulars in that galaxy. No such metallicity dependent luminosity difference is observed among the globular clusters associated with the Milky Way System. Furthermore the NGC 5128 cluster sample contains two objects that, on the basis of their observed colors appear to be super metal-poor. It is speculated that many of these apparently faint and metal-poor clusters in NGC 5128 are actually objects resembling intermediate-age Galactic open clusters. It is also found that large clusters with FWHM > 10 pc are typically less luminous in NGC 5128 than are their more more compact counterparts. In this respect the NGC 5128 cluster system is similar to the Galactic globular cluster system, in which large clusters also tend to be less luminous than compact ones. Finally, the present data may hint at the possibility that the NGC 5128 cluster system differs from that surrounding the Milky Way, in the sense that the NGC 5128 objects do not seem to exhibit a clear cut gap between the regions of the FWHM vs Mv plane that are occupied by globular clusters and by dwarf spheroidal galaxies. Subject headings: globular clusters: general galaxies individual (NGC 5128, Galaxy)
منابع مشابه
Astronomy and Astrophysics Deep Vlt Search for Globular Clusters in Ngc 5128: Color-magnitude Diagrams and Globular Cluster Luminosity Function ⋆
At the distance of NGC 5128 (3.6±0.2 Mpc) it is possible to resolve globular clusters with high resolution imaging from the ground, thus allowing the globular cluster candidate selection primarily through their morphological properties. I report the discovery of 71 globular clusters in NGC 5128 on VLT UT1+FORS1 images, including the faintest members (MV ∼ −5) known to date in this galaxy as wel...
متن کاملA Population of Massive Globular Clusters in Ngc 5128
We present velocity dispersion measurements of 14 globular clusters in NGC 5128 (Centarus A) obtained with the MIKE echelle spectrograph on the 6.5m Magellan Clay telescope. These clusters are among the most luminous globular clusters in NGC 5128 and have velocity dispersions comparable to the most massive clusters known in the Local Group, ranging from 10 – 30 km s−1. We describe in detail our...
متن کاملThe Centaurus Group and the Outer Halo of NGC 5128 : Are they Dynamically Connected ?
NGC 5128, a giant elliptical galaxy only ∼ 4 Mpc away, is the dominant member of a galaxy group of over 80 probable members. The Centaurus group provides an excellent sample for a kinematic comparison between the halo of NGC 5128 and its surrounding satellite galaxies. A new study, presented here, shows no kinematic difference in rotation amplitude, rotation axis, and velocity dispersion betwee...
متن کاملMassive Globular Clusters In
We present velocity dispersion measurements of 14 globular clusters in NGC 5128 (Centarus A) obtained with the MIKE echelle spectrograph on the 6.5m Magellan Clay telescope. These clusters are among the most luminous globular clusters in NGC 5128 and have velocity dispersions comparable to the most massive clusters known in the Local Group, ranging from 10 – 30 km s−1. We describe in detail our...
متن کاملGlobular clusters in NGC 5128 ?
We used the Wide Field Planetary Camera 2 aboard the Hubble Space Telescope to search for globular clusters in the inner regions of the nearby giant elliptical galaxy NGC 5128. This galaxy is believed to be the product of a merger between a large elliptical galaxy and a small late-type spiral between 160 and 500 Myr ago. We identified 21 globular cluster candidates and measured their core radii...
متن کامل