Results 81 to 90 of about 4,320,326 (297)
The Astrophysical JournalInternal gas inflows driven by galaxy mergers are considered to enhance star formation rates (SFRs), fuel supermassive black hole growth, and stimulate active galactic nuclei (AGNs).
Kiyoaki Christopher Omori +8 more
doaj +1 more source
The Astrophysical JournalAccretion supermassive black holes in the center of active galaxies usually produce “jet”-collimated bipolar outflows of relativistic particles. Magnetic fields near the black hole event horizon may play a crucial role in the formation of jets/outflows ...
Yongyun Chen +6 more
doaj +1 more source
ISO observations of four active galaxies
, 2003 We present ISO PHOT-S spectra of four galaxies known or suspected to host a central AGN, selected from the initial Iras/Rosat sample of Boller et al. (1992).
Bassani +35 more
core +2 more sources
On characterizing the variability properties of X-ray light curves from active galaxies [PDF]
, 2003 We review some practical aspects of measuring the amplitude of variability in 'red noise' light curves typical of those from active galactic nuclei (AGN). The quantities commonly used to estimate the variability amplitude in AGN light curves, such as the
S. Vaughan +7 more
semanticscholar +1 more source
The Astrophysical JournalInfrared-faint radio sources (IFRSs) are believed to be a rare class of radio-loud active galactic nuclei (AGNs) characterized by their high radio-to-infrared flux density ratios of up to several thousand.
Yihang Zhang +6 more
doaj +1 more source
The spectral-type/luminosity and the spectral type/satellite-density relations in the 2dFGRS
, 2005 We examine the relative fractions of passive (Type 1), quiet-SF (Type 2) and active-SF (Type 3+4) galaxies as a function of luminosity and number of neighbours in several volume limited samples selected from the 2dFGRS.
B. Kelm +42 more
core +1 more source
AGN STORM 2. VIII. Investigating the Narrow Absorption Lines in Mrk 817 Using HST-COS Observations
The Astrophysical JournalWe observed the Seyfert 1 galaxy Mrk 817 during an intensive multiwavelength reverberation mapping campaign for 16 months. Here, we examine the behavior of narrow UV absorption lines seen in the Hubble Space Telescope/Cosmic Origins Spectrograph spectra,
Maryam Dehghanian +41 more
doaj +1 more source
A New Physical Picture for Active Galactic Nuclei Lacking Optical Emission Lines
The Astrophysical Journal, 2023 In this work, we use ∼500 low-redshift ( z ∼ 0.1) X-ray active galactic nuclei (AGNs) observed by XMM-Newton and the Sloan Digital Sky Survey (SDSS) to investigate the prevalence and nature of AGNs that apparently lack optical emission lines (“optically ...
Christopher J. Agostino +4 more
doaj +1 more source
Radio Sources in the 2dF Galaxy Redshift Survey. I. Radio Source Populations [PDF]
, 1999 We present the first results from a study of the radio continuum properties of galaxies in the 2dF Galaxy Redshift Survey, based on thirty 2dF fields covering a total area of about 100 square degrees.
C. A. Jackson +7 more
core +3 more sources
The mean star formation rate of X-ray selected active galaxies and its evolution from z~2.5: results from PEP-Herschel [PDF]
, 2012 We study relationships between star-formation rate (SFR) and the accretion luminosity and nuclear obscuration of X-ray selected active galactic nuclei (AGNs) using a combination of deep far-infrared (FIR) and X-ray data in three key extragalactic survey ...
D. Rosario +43 more
semanticscholar +1 more source