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Gas accretion as the origin of chemical abundance gradients in distant galaxies
Cosmology and Extragalactic Astrophysics (astro-ph.CO)
2010/12/29
It has recently been suggested that galaxies in the early Universe can grow through the accretion of cold gas, and that this may have been the main driver of star formation and stellar mass growth.
Properties of Bulgeless Disk Galaxies: I. Atomic Gas
Cosmology and Extragalactic Astrophysics (astro-ph.CO)
2010/12/29
We study the neutral hydrogen properties of a sample of twenty bulgeless disk galaxies (Sd - Sdm Hubble types), an interesting class because their morphological simplicity implies that they have evolv...
Automated Morphological Classification of SDSS Red Sequence Galaxies
Cosmology and Extragalactic Astrophysics (astro-ph.CO)
2010/12/29
In the last decade, the advent of enormous galaxy surveys has motivated the development of automated morphological classification schemes to deal with large data volumes. Existing automated schemes ca...
Bound and unbound substructures in Galaxy-scale Dark Matter haloes
Cosmology and Extragalactic Astrophysics (astro-ph.CO)
2010/12/29
We analyse the coarse-grained phase-space structure of the six Galaxy-scale dark matter haloes of the Aquarius Project using a state-of-the-art 6D substructure finder. Within r_50, we find that about ...
Using archival Spitzer Space Telescope data, we identified for the first time a dozen runaway OB stars in the Small Magellanic Cloud (SMC) through the detection of their bow shocks. The geometry of de...
Dense Molecular Gas Excitation in Nuclear Starbursts at High Redshift: HCN, HNC, and HCO+(J=6-5) Emission in the z=3.91 Quasar Host of APM08279+5255
Cosmology and Extragalactic Astrophysics (astro-ph.CO)
2010/12/29
We report the detection of surprisingly strong HCN, HNC, and HCO+(J=6-5) emission in the host galaxy of the z=3.91 quasar APM08279+5255 through observations with CARMA. HCN, HNC, and HCO+ are typicall...
The effect of curvature in thawing models
Cosmology and Extragalactic Astrophysics (astro-ph.CO) General Relativity and Quantum Cosmology (gr-qc)
2010/12/29
We study the evolution of spatial curvature for thawing class of dark energy models. We examine the evolution of the equation of state parameter, $w_\phi$, as a function of the scale factor $a$, for t...
Possible Signatures of Magnetospheric Accretion onto Young Giant Planets
Solar and Stellar Astrophysics (astro-ph.SR)
2010/12/29
Magnetospheric accretion is an important process for a wide range of astrophysical systems, and may play a role in the formation of gas giant planets. Extending the formalism describing stellar magnet...
An Initial Mass Function for Individual Stars in Galactic Disks: I. Constraining the Shape of the IMF
Galaxy Astrophysics (astro-ph.GA)
2010/12/29
We derive a semi-empirical galactic initial mass function (IMF) from observational constraints. We assume that the star formation rate in a galaxy can be expressed as the product of the IMF, $\psi (m)...
Could the Hercules satellite be a stellar stream in the Milky Way halo?
Galaxy Astrophysics (astro-ph.GA)
2010/12/29
We investigate the possibility that Hercules, a recently discovered Milky Way (MW) satellite, is a stellar stream in the process of formation. This hypothesis is motivated by Hercules' highly elongate...
The HST/ACS Coma Cluster Survey III. Structural Parameters of Galaxies using single-Sérsic Fits
Cosmology and Extragalactic Astrophysics (astro-ph.CO)
2010/12/29
We present a catalogue of structural parameters for 8814 galaxies in the 25 fields of the HST/ACS Coma Treasury Survey. Parameters from S\'ersic fits to the two-dimensional surface brightness distribu...
Nearby early-type galaxies with ionized gas VI. The Spitzer-IRS view
Cosmology and Extragalactic Astrophysics (astro-ph.CO)
2010/12/29
We present low resolution Spitzer-IRS spectra of 40 ETGs, selected from a sample of 65 ETGs showing emission lines in their optical spectra. We homogeneously extract the mid-infrared (MIR) spectra, an...
The evolution of luminosity, colour and the mass-to-luminosity ratio of Galactic open clusters: comparison of discrete vs. continuous IMF models
Galaxy Astrophysics (astro-ph.GA)
2010/12/29
We found in previous studies that standard Simple Stellar Population (SSP) models are unable to describe or explain the colours of Galactic open clusters both in the visible and in the NIR spectral ra...
On the fairness of the main galaxy sample of SDSS
Cosmology and Extragalactic Astrophysics (astro-ph.CO)
2010/12/29
In order to measure fairness of the main galaxy sample of SDSS, series of flux-limited and volume-limited samples are constructed from SDSS data releases DR4, DR6 and DR7 for analysis with various sta...
Cluster number counts in quintessence models
Cosmology and Extragalactic Astrophysics (astro-ph.CO)
2010/12/29
Even though the abundance and evolution of clusters have been used to study the cosmological parameters including the properties of dark energy owing to their pure dependence on the geometry of the Un...