Probing Halos with PNe: Mass and Angular Momentum in Early-Type Galaxies
نویسنده
چکیده
We present an observational survey program using planetary nebulae, globular clusters, and X-ray emission to probe the halos of early-type galaxies. We review evidence for scanty dark matter halos around ordinary elliptical galaxies, and discuss the possible implications. We also present measurements of rotation in the halos.
منابع مشابه
Planetary nebulae as mass tracers of their parent galaxies: biases in the estimate of the kinematical quantities
Multi-object and multi-fiber spectrographs on 4 and 8 meter telescopes make it possible to use extragalactic planetary nebulae (PNe) in the outer halos of early-type galaxies as kinematical tracers, where classical techniques based on integrated stellar light fail. Until now, published PNe radial velocity samples are small, with only a few tens of radial velocity measurements (except for a few ...
متن کاملInternal and External Alignment of the Shapes and Angular Momenta of Λcdm Halos
We investigate how the shapes and angular momenta of galaxy and group mass dark matter halos in a ΛCDM N -body simulation are correlated internally, and how they are aligned with respect to the location and properties of surrounding halos. We explore these relationships down to halos of much lower mass (10 h−1 M⊙) than previous studies. The halos are triaxial, with c/a ratios of 0.6± 0.1 and a ...
متن کاملThe Angular Momentum of Gas in Proto-galaxies: I – Implications for the Formation of Disk Galaxies
We use non-radiative N-body/SPH simulations of structure formation in a ΛCDM cosmology to compare the angular momentum distributions of dark matter and gas in a large sample of halos. We show that the two components have identical spin parameter distributions and that their angular momentum distributions within individual halos are very similar, all in excellent agreement with standard assumpti...
متن کاملGalaxies in a Λ CDM Universe
We compute the locations of satellite galaxies with respect to their hosts using the ΛCDM GIF simulation. If the major axes of the hosts' images are perfectly aligned with the major axes of their projected mass, the satellites are located preferentially close to the hosts' major axes. In this case, the degree of anisotropy in the satellite locations is a good tracer of the flattening of the hos...
متن کاملThe angular momentum of dark halos: merger and accretion effects
We present new results on the angular momentum evolution of dark matter halos. Halos, from N-body simulations, are classified according to their mass growth histories into two categories: the accretion category contains halos whose mass has varied continuously and smoothly, while the merger category contains halos which have undergone sudden and significant mass variations (greater than 1/3 of ...
متن کامل