1,328 datasets found

We present results from four years of twice-weekly 15GHz radio monitoring of about 1500 blazars with the Owens Valley Radio Observatory 40m telescope. Using the intrinsic...

Mid-infrared (MIR) quasar spectra exhibit a suite of emission features including high ionization coronal lines from the narrow-line region illuminated by the ionizing continuum,...

We present a catalogue of about six million unresolved photometric detections in the Sloan Digital Sky Survey (SDSS) Seventh Data Release, classifying them into stars, galaxies...

NRAO 530 is an optically violent variable source and has been studied with multi-epoch multifrequency high-resolution very long baseline interferometry (VLBI) observations. NRAO...

The first stars were born from chemically pristine gas. They were likely massive, and thus they rapidly exploded as supernovae, enriching the surrounding gas with the first...

We report 6yr monitoring of distant bright quasar CTS C30.10 (z=0.90052) with the Southern African Large Telescope. We measured the rest-frame time lag of 562_-68_^+116^ days...

Even with several thousand Fermi-Large Area Telescope (LAT) blazar detections, the {gamma}-ray emission mechanism is poorly understood. We explore correlated optical/{gamma}-ray...

X-ray polarization should provide new probes of magnetic field geometry and acceleration physics near the base of blazar jets, but near-future missions will have limited...

We present accretion disk structure measurements from continuum lags in the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project. Lags are measured using the JAVELIN...

The unified model of active galactic nuclei (AGNs) proposes that different AGN optical spectral types are caused by different viewing angles with respect to an obscuring...

Active galactic nuclei (AGNs) that show strong rest-frame optical/UV variability in their blue continuum and broad line emission are classified as changing-look AGN, or at...

We exploit the widely separated images of the lensed quasar SDSSJ1029+2623 (z_em_=2.197, {theta}=22.5") to observe its outflowing wind through two different sightlines. We...

We explore the practical feasibility of active galactic nucleus (AGN) broadband reverberation mapping and present first results. We lay out and apply a rigorous approach for the...

We present photometry of the large-scale environments of a sample of 12 broad line active galactic nuclei (AGNs) with 0.06<z<0.37 from deep images in the Sloan Digital Sky...

A new method is used to measure the physical conditions of the gas in damped Ly{alpha} systems (DLAs). Using high-resolution absorption spectra of a sample of 80 DLAs, we are...

The gravitationally lensed quasar HE 1104-1805 has been observed at a variety of wavelengths ranging from the mid-infrared to X-ray for nearly 20yr. We combine flux ratios from...

We report on the acceleration properties of 329 features in 95 blazar jets from the MOJAVE Very Long Baseline Array program. Nearly half the features and three-quarters of the...

We consider how the profile and multi-year variability properties of a large sample of C IV Broad Absorption Line (BAL) troughs change when BALs from Si IV and/or Al III are...

We have vastly increased the CIV statistics at intermediate redshift by surveying the thousands of quasars in the Sloan Digital Sky Survey (SDSS) Data-Release 7. We visually...

The hosts of luminous z~2 quasars evolve into today's massive elliptical galaxies. Current theories predict that the circumgalactic medium (CGM) of these massive, dark matter...