相关论文: Radio galaxy evolution: what you can learn from a …
The incidence of young but fading radio sources provides important information on the life cycle of radio emission in radio-loud active galactic nuclei. Despite its importance for constraining the models of radio source evolution, there are…
We have explored, in the general framework of the ``young source'' scenario, evolutionary models for GHz Peaked Spectrum (GPS) galaxies and quasars which reproduce the observed counts, redshift and peak frequency distributions of currently…
Galaxy redshift surveys using optical telescopes have, in combination with other cosmological probes, enabled precision measurements of the nature of dark energy. We show that radio telescopes are rapidly becoming competitive with optical…
The radio continuum emission from the Galaxy has a rich mix of thermal and non-thermal emission. This very richness makes their interpretation challenging since the low radio opacity means that a radio image represents the sum of all…
This aims to be an overview of what detailed observations of individual stars in nearby dwarf galaxies may teach us about galaxy evolution. This includes some early results from the DART (Dwarf Abundances and Radial velocity Team) Large…
I review progress in the past few years in studying the large-scale structure of the universe through redshift surveys of galaxies. Of the many statistical methods used to describe the galaxy distribution, I concentrate here on the power…
A brief summary of some highlights in the study of high energy astrophysical sources over the past decade is presented. It is argued that the great progress that has been made derives largely from the application of new technology to…
We constructed and presented in the first paper of this series a new sample of 84 large angular size radio galaxies by selecting from the NRAO VLA Sky Survey objects with angular size > 4', declination above +60 degrees and total flux…
We determine the radio and optical luminosity evolutions and the true distribution of the radio loudness parameter R, defined as the ratio of the radio to optical luminosity, for a set of more than 5000 quasars combining SDSS optical and…
Gravitational waves inform about the probable distances at which an observed signal originated. This information when combined over multiple observations is used in the modeling of the redshift evolution of the merger rate. This is an…
The long-awaited promise of studying high-redshift galaxies at long wavelengths has been partially eclipsed by progress at optical wavelengths, mostly because of the number of available pixels. It is nonetheless essential to study optically…
Radio emission has been detected from all the stages of stellar evolution across the HR Diagram. Its presence reveals both astrophysical phenomena and stellar activity which, otherwise, would not be detectable by other means. The…
The luminosity-redshift relation of cosmological standard candles provides information about the relative energy composition of our Universe. In particular, the observation of type Ia supernovae up to redshift of z~2 indicate a universe…
This paper presents the results of a photometric redshift study of galaxies in the Hubble Deep Field (HDF). The method of determining redshifts from broadband colors is described, and the dangers inherent in using it to estimate redshifts,…
The "ringdown" radiation emitted by oscillating black holes has great scientific potential. By carefully predicting the frequencies and amplitudes of black hole quasinormal modes and comparing them with gravitational-wave data from compact…
Multifrequency Very Long Baseline Array (VLBA) observations were performed to study the radio morphology and the synchrotron spectra of four high frequency peaking radio sources. They are resolved in several compact components and the radio…
I assess the problem of morphological and photometric evolution of high-redshift galaxies in the ultraviolet wavelength range. My discussion will partly rely on a new set of template galaxy models, in order to infer the expected changes…
Spectral variability of radio sources encodes information about the conditions of intervening media, source structure, and emission processes. With new low-frequency radio interferometers observing over wide fractional bandwidths, studies…
We present the results of sub-arcsecond 108 GHz continuum interferometric observations toward the radio luminous galaxy 3C123. Using multi-array observations, we utilize the high u,v dynamic range of the BIMA millimeter array to sample…
We point out that the remarkable linearity of the ultra-steep radio spectra of high redshift radio galaxies reflects a previously reported general trend for powerful radio galaxies, according to which the spectral curvature is lesser for…