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Variations in 24-mu m morphologies among galaxies in the Spitzer Infrared Nearby Galaxies Survey: new insights into the Hubble sequence
ISM structure
2014/12/23
To study the distribution of star formation and dust emission within nearby galaxies, we measured five morphological parameters in the 3.6- and 24-μm wavebands for 65 galaxies in the Spitzer Infrared ...
Vibrational Instability of Metal-Poor Low-Mass Main-Sequence Stars
Vibrational Instability Metal-Poor Low-Mass Main-Sequence Stars
2012/2/24
We find that low-degree low-order g-modes become unstable in metal-poor low-mass stars due to the $\varepsilon$-mechanism of the pp-chain. Since the outer convection zone of these stars is limited onl...
Habitability of Super-Earth Planets around Main-Sequence Stars including Red Giant Branch Evolution: Models based on the Integrated System Approach
Main-Sequence Stars including Red Giant Branch Evolution Models based Integrated System Approach
2011/10/20
In a previous study published in Astrobiology, we focused on the evolution of habitability of a 10 M_E super-Earth planet orbiting a star akin to the Sun. This study was based on a concept of planetar...
Galaxy evolution in groups and clusters: star formation rates, red sequence fractions, and the persistent bimodality
methods: statistical-galaxies: groups: general-galaxies: clusters:general-galaxies: haloes-galaxies: evolution-galaxies: star formation
2011/10/17
Using galaxy group/cluster catalogs created from the Sloan Digital Sky Survey Data Release 7, we examine in detail the specific star formation rate (SSFR) distribution of satellite galaxies and its de...
From the Blazar Sequence to the Blazar Envelope: Revisiting the Relativistic Jet Dichotomy in Radio-loud AGN
Blazar Envelope Revisiting Relativistic Jet Dichotomy Radio-loud AGN
2011/10/21
We revisit the concept of a blazar sequence that relates the synchrotron peak frequency ({\nu}peak) in blazars with synchrotron peak luminosity (Lpeak, in {\nu}L{\nu}) using a large sample of radio-lo...
Galaxy-galaxy lensing constraints on the relation between baryons and dark matter in galaxies in the Red Sequence Cluster Survey 2
gravitational lensing: weak - galaxies: formation - galaxies: halos
2011/10/12
We present the results of a study of weak gravitational lensing by galaxies using imaging data that were obtained as part of the second Red Sequence Cluster Survey (RCS2). In order to compare to the b...
The white dwarf cooling sequence of NGC 6791: a unique tool for stellar evolution
stars: white dwarfs – stars: luminosity function, mass function – (Galaxy:) open clusters and associations: general –(Galaxy:) open clusters and associations: individual: NGC 6791
2011/10/9
NGC 6791 is a well-studied, metal-rich open cluster that is so close to us that can be imaged down to luminosities fainter than that of the termination of its white dwarf cooling sequence, thus allowi...
We investigate the origin of the color-magnitude relation (CMR) observed in cluster galaxies by using a combination of a cosmological N-body simulation of a cluster of galaxies and a semi-analytic mod...
We report the discovery of cool DZ white dwarfs, which lie in the SDSS (u-g) vs. (g-r) two-color diagram across and below the main sequence. These stars represent the extension of the well-known DZ se...
Abundance anomalies in pre-main-sequence stars: Stellar evolution models with mass loss
Diffusion — stars chemically peculiar — stars mass–loss — stars pre–main-sequence — stars evolution — stars
2010/11/12
Aims. The effects of atomic diffusion on internal and surface abundances of A and F pre–main-sequence stars with mass loss are studied in order to determine at what age the effects materialize, as wel...
Revisiting the Hubble sequence in the SDSS DR7 spectroscopic sample: a publicly available bayesian automated classification
Cosmology and Extragalactic Astrophysics (astro-ph.CO) Instrumentation and Methods for Astrophysics (astro-ph.IM)
2011/1/5
We present an automated morphological classification in 4 types (E,S0,Sab,Scd) of ~700.000 galaxies from the SDSS DR7 spectroscopic sample based on support vector machines. The main new property of th...
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...
Absolute properties of BG Ind - a bright F3 system just leaving the Main Sequence
Solar and Stellar Astrophysics (astro-ph.SR)
2010/12/27
We present photometric and spectroscopic analysis of the bright detached eclipsing binary BG Ind. The masses of the components are found to be 1.428 +- 0.008 and 1.293 +- 0.008 Msun and the radii to b...
Extreme Enhancements of r-process Elements in the Cool Metal-Poor Main-Sequence Star SDSS J2357-0052
Solar and Stellar Astrophysics (astro-ph.SR)
2010/12/23
We report the discovery of a cool metal-poor, main-sequence star exhibiting large excesses of r-process elements. This star is one of two newly discovered cool subdwarfs (effective temperatures of 500...
The Effect of Screening Factors and Thermonuclear Reaction Rates in the Pre-main Sequence Evolution of Low Mass Stars
Low mass stars thermonuclear reaction rates electron screening factors composition changes
2010/9/15
In understanding the nucleosynthesis of the elements in stars,one of the most important quantities is the reaction rate and it must be evaluated in terms of the stellar temperature T , and its determi...
