Nuclear Activity in Nearby Galaxies

By Luis C. Ho. 2008

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A significant fraction of nearby galaxies show evidence of weak nuclear activity unrelated to normal stellar processes. Recent high-resolution, multiwavelength observations indicate that the bulk of this activity derives from black hole accretion with a wide range of accretion rates. The low accretion rates that typify most low-luminosity active galactic nuclei induce significant modifications to their central engine. The broad-line region and obscuring torus disappear in some of the faintest sources, and the optically thick accretion disk transforms into a three-component structure consisting of an inner radiatively inefficient accretion flow, a truncated outer thin disk, and a jet or outflow. The local census of nuclear activity supports the notion that most, perhaps all, bulges host a central supermassive black hole, although the existence of active nuclei in at least some late-type galaxies suggests that a classical bulge is not a prerequisite to seed a nuclear black hole.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/a730708358ae2f543ace16d2bad74ac2d374127a

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Citations in the corpus

RADIATIVELY INEFFICIENT ACCRETION IN NEARBY GALAXIES (2009, background): “Consistent with this picture, low-leve nuclear activity qualitatively resembling that of more luminous AGNs is found to be equally pervasive in nearby galaxies (Ho et al. 1997b; Ho 2008).”
RADIO-LOUD NARROW-LINE SEYFERT 1 AS A NEW CLASS OF GAMMA-RAY ACTIVE GALACTIC NUCLEI (2009, background): “Indeed, blazar-like radio emission from radio-quiet AGNs has been already reported (e.g., Brunthaler et al. 2000, 2005; Lister et al. 2009; see also the review by Ho 2008), but no γ rays have been yet detected from these sources.”
General physical properties of bright Fermi blazars (2009, result): “Notably, there are hints that similar results holds forradio-quietsources (e.g. Ho 2009; see also Ho 2008 for review).”
An X-ray view of 82 LINERs with Chandra and XMM-Newton data (2009, background): “These studies are especially important for low luminosity AGN (LLAGN) with bolometric luminosities LB 1044erg s−1 because more than 40% of nearby galaxies show evidence for low-power AGN (see the review by Ho, 2008).”
DISCOVERY OF AN ACTIVE GALACTIC NUCLEUS DRIVEN MOLECULAR OUTFLOW IN THE LOCAL EARLY-TYPE GALAXY NGC 1266 (2011, background): “…the nuclear region to sustain this luminosity of warm H2 would require an AGN with a bolometric luminosity of & 2×1044 erg s−1, assuming first that LX,AGN & 100LH2,warm, Ogle et al. 2010; and Lbol,AGN & 16LX , Ho 2008), a factor of three larger than LFIR (7 × 10 43 erg s−1; Gil de Paz et al. 2007).”
General relativistic magnetohydrodynamical simulations of the jet in M 87 (2015, background): “The M87 core is a prototype of a radio loud low-luminosity active galactic nuclei (Ho 2008, and references therein).”
The Coevolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe (2014, methodology): “The geometrically-thin accretion disk is either absent, or is truncated in the inner regions, and is replaced by a geometrically-thick structure in which the inflow time is much shorter than the radiative cooling time (e.g. Narayan & Yi 1994, 1996, Quataert 2001, Narayan 2005, Ho 2008).”
A NEW DIAGNOSTIC OF ACTIVE GALACTIC NUCLEI: REVEALING HIGHLY ABSORBED SYSTEMS AT REDSHIFT >0.3 (2011, background): “The detection fraction is typically high, ranging from 50% to 70% (see the review by Ho 2008, and references therein).”
STRUCTURE AND FORMATION OF ELLIPTICAL AND SPHEROIDAL GALAXIES (2008, background): “…disks (Filippenko& Ho 2003; Barth et al. 2004; Greene & Ho 2004, 2007; Peterson et al. 2005; Greene, Barth, & Ho 2006; Shields et al. 2008; Barth, Greene, & Ho 2008; Thornton et al. 2008; see Ho 2008 for a review), but BH masses correlate very little with theirhost disks (Kormendy & Gebhardt 2001).”
The Sydney-AAO Multi-object Integral field spectrograph (2011, background): “At an even more fundamental level, the fraction of galaxies which host AGN is only well defined locally (i.e. 10s of Mpc; Ho 2008).”
THE ULTRAVIOLET-BRIGHT, SLOWLY DECLINING TRANSIENT PS1-11af AS A PARTIAL TIDAL DISRUPTION EVENT (2013, background): “However, we cannot exclude the possibility of a low-luminosity AGN, as samples in the local universe extend to significantly lower emission-line luminosities than our limits for the host of PS1-11af (Ho 2008; Hao et al. 2005).”
NUMERICAL SIMULATION OF HOT ACCRETION FLOWS. II. NATURE, ORIGIN, AND PROPERTIES OF OUTFLOWS AND THEIR POSSIBLE OBSERVATIONAL APPLICATIONS (2012, background): “This picture has received observational supports (see Yuan 2007, Ho 2008 for reviews).”
RECONSTRUCTING THE STELLAR MASS DISTRIBUTIONS OF GALAXIES USING S4G IRAC 3.6 AND 4.5 μm IMAGES. I. CORRECTING FOR CONTAMINATION BY POLYCYCLIC AROMATIC HYDROCARBONS, HOT DUST, AND INTERMEDIATE-AGE STARS (2011, background): “…particular case, the mid-IR emission can be associated with the signature “big red bump” emission from a truncated accretion disk (Ho et al. 1996; Ho 2008; Quataert et al. 1999), but emisson from an extended hot dust component as far out as 75” (possibly heated by the AGN) presumably also…”
DWARF GALAXIES WITH OPTICAL SIGNATURES OF ACTIVE MASSIVE BLACK HOLES (2013, background): “LINER emission can be generated both by shocks and very hard AGN spectra, and disentangling the primary origin in any given case can be complicated and aperture dependent (e.g., Kewley et al. 2006; Sarzi et al. 2006; Ho 2008; Eracleous et al. 2010; Yan & Blanton 2012).”