Related papers: Flickering Faint Galaxies: Few and Far Between
We report the discovery of 13 broad-line AGNs at $z = 5 - 8$ from the first 10% data of the JWST Cycle 3 Treasury Program COSMOS-3D. These AGNs are identified by their broad H$\alpha$ or H$\beta$ emission lines through the NIRCam grism…
We examine whether the spectral energy distribution of optical continuum emission of active galactic nuclei (AGNs) changes during flux variation, based on accurate and frequent monitoring observations of 11 nearby Seyfert galaxies and QSOs…
Deep X-ray surveys have resolved much of the X-ray background radiation below 2 keV into discrete sources, but the background above 8 keV remains largely unresolved. The obscured (type 2) Active Galactic Nuclei (AGNs) that are expected to…
We present an analysis of quasar variability from data collected during a photometric monitoring of 50 objects carried out at CNPq/Laboratorio Nacional de Astrofisica, Brazil, between March 1993 and July 1996. A distinctive feature of this…
The number of close pairs of galaxies observed to faint magnitude limits, when compared to nearby samples, determines the interaction or merger rate as a function of redshift. The prevalence of mergers at intermediate redshifts is…
We study the optical properties of a large sample of galaxies in low-density regions of the nearby universe. We make a 5/h Mpc-smoothed map of the galaxy density throughout the Center for Astrophysics Redshift Survey (CfA2) to identify…
The frequency and effects of multiple weak deflections in galaxy-galaxy lensing are investigated via Monte Carlo simulations. The lenses in the simulations are galaxies with known redshifts and known rest-frame blue luminosities. The…
Studying simultaneous optical and X-ray light curves of radio-quiet AGN can help to probe the relationship between very different physical components - the cool, optically thick disk and hot, optically thin corona. Here, we review the…
Both theoretical and observational lines of reasoning suggest that the very faint (B > 24) galaxies seen in deep images of the sky are small low-mass galaxies that experienced starburst at 0.5<z<1 and have since faded into low luminosity,…
We combine photometry and lens modeling to study the properties of 17 gravitational lens galaxies between z=0.1 and 1. Most of the lens galaxies are passively evolving early-type galaxies, with a few spirals. The colors, scale lengths, and…
{}From deep optical images of three clusters selected by virtue of their X-ray luminosity and/or optical richness (1455+22; $z=0.26$, 0016+16; $z=0.55$ and 1603+43; $z=0.89$), we construct statistically-complete samples of faint field…
Promising methods for studying galaxy evolution rely on optical emission line width measurements to compare intermediate-redshift objects to galaxies with equivalent masses at the present epoch. However, emission lines can be misleading. We…
BL Lac objects (BLL) are defined by the presence of very weak (typically $<$ 5 {\AA}) or even absent spectral lines. This makes determining their distance particularly challenging, especially at high redshift, where the sources are fainter…
We adopt a new approach to explore the puzzling nature of faint blue field galaxies. Instead of assuming that the local luminosity function is well defined, we first determine whether any non-evolving set of luminosity functions for…
We build a simple physical model to study the high-redshift active galactic Nucleus (AGN) evolution within the co-evolution framework of central black holes (BHs) and their host galaxies. The correlation between the circular velocity of a…
We report the discovery of a highly X-ray variable AGN, RX J2217.9-5941. This object was bright during the ROSAT All-Sky Survey (RASS), during which a decrease in the count rate by a factor of 12 was observed. It was found to be much…
Approximately half of all disc galaxies exhibit appreciable warps in both their stellar and HI discs. The typical warp amplitude is small (a few degrees), and only becomes noticeable at the periphery of the galaxy disc. As a result, warps…
Many galaxies appear to have taken on their familiar appearance relatively recently. In the distant Universe, galaxy morphology started to deviate significantly (and systematically) from that of nearby galaxies at redshifts, z, as low as z…
We use mid-infrared variability in galaxies to search for active galactic nuclei (AGN) in the local universe. We use a sample of 10,220 galaxies from the Mapping Nearby Galaxies at APO (MaNGA) survey, part of the Sloan Digital Sky Survey…
Variability is one of the hallmarks of Active Galactic Nuclei. The Burst Alert Telescope onboard of Swift, with its homogeneous coverage of the sky is a formidable tool to study variability at hard X-rays. We present here the analysis of…