相关论文: Quasars and the Hubble Relation

The recent discoveries of luminous quasars at high redshifts imply that black holes more massive than a few billion solar masses have been assembled already when the universe was less than a billion years old. We show that the existence of…

Feedback, in particular from active galactic nuclei (AGN), is believed to play a crucial role in the evolution of galaxies. In the local Universe, many galaxies with an AGN are indeed observed to reside in the so-called green valley,…

Quasars are the most luminous non-transient sources in the epoch of cosmological reionization (i.e., which ended a billion years after the Big Bang, corresponding to a redshift of z ~ 5), and are powerful probes of the inter-galactic medium…

We explore how the local environment is related to the redshift, type, and luminosity of active galactic nuclei (AGN). Recent simulations and observations are converging on the view that the extreme luminosity of quasars is fueled in major…

Blazars are sources whose jet is pointing to us. Since their jets are relativistic, the flux is greatly amplified in the direction of motion, making blazars the most powerful persistent objects in the Universe. This is true at all…

We present a simple model of how quasars occupy dark matter halos from z=0 to z=5 using the observed mBH-sigma relation and quasar luminosity functions. This provides a way for observers to statistically infer host halo masses for quasar…

Optical variability in galaxies at high redshift is a tracer of evolution in AGN activity, and should provide a useful constraint on models of galaxy evolution, AGN structure, and cosmology. We studied optical variability in multiple deep…

Active Galactic Nuclei (AGN) are intensely accreting supermassive black holes at the centers of massive galaxies. Though these objects occupy little spatial extent of the galaxy itself, they are thought to have far reaching affects,…

Of the many ways of detecting high redshift galaxies, the selection of objects due to their redshifted Ly-alpha emission has become one of the most successful. But what types of galaxies are selected in this way? Until recently, Ly-alpha…

Active galaxies are often associated with starbursts, which are possible sources of fuelling for the nuclear black holes. By means of optical (3500-7500 A) spectroscopic and narrow-band photometric data (H_alpha+[NII]6548,6583 and…

The concept of the evolutionary sequence of jetted active galactic nuclei (AGNs) has been challenged in the last few decades since AGN subclasses are considered to be different due to their viewing angle. In this paper, we collected a…

The formation rate of luminous galaxies seems to be roughly constant from z~2 to z~4 from the recent observations of Lyman break galaxies (LBGs) (Steidel et al 1999). The abundance of luminous quasars, on the other hand, appears to drop off…

A galaxy's orientation is one of its most basic observable properties. Astronomers once assumed that galaxies are randomly oriented in space, however it is now clear that some have preferred orientations with respect to their surroundings.…

The relationship between galaxies and supermassive black holes (SMBH) found in their cores plays a key role in the formation and evolution of both of these major constituents of the universe, as well as the evolution of the intergalactic…

Based on a comparison of the SRG/eROSITA catalog of X-ray active stars and the Gaia catalog, a sample of 502 peculiar objects was obtained for which Gaia, on one hand, detects statistically significant values of parallax or proper motion…

We present a semi-analytic model of isolated dwarf galaxy evolution and use it to study the build-up of observed correlations between dwarf galaxy properties. We analyse the evolution using models with averaged and individual halo mass…

We explore the properties of galaxies in the proximity (within a $\sim$2 Mpc radius sphere) of Type I quasars at 0.1<z<0.35, to check whether and how an active galaxy influences the properties of its neighbors. We further compare these with…

Beyond black holes and neutron stars, new hypothetical compact objects have been proposed as potential astrophysical entities. In general, their properties have not yet been fully explored or understood, nor has it been proven whether or…

We present a catalog of 30 QSOs and their spectra, in the square degree of sky centered on the northern Hubble Deep Field. These QSOs were selected by multicolor photometry and subsequently confirmed with spectroscopy. They range in…

An analysis of more than 3000 galaxies resolved at better than 114 pc/h at z=0.62 in a LAOZI cosmological adaptive mesh refinement hydrodynamic simulation is performed and insights gained on star formation quenching and color migration. The…