A New Sample of Low-Mass Black Holes in Active Galaxies

By Jenny E. Greene, Luis C. Ho. 2007

311 citations recorded by the source corpus.

We present an expanded sample of low-mass black holes (BHs) found in galactic nuclei. Using standard virial mass techniques to estimate BH masses, we select from the Fourth Data Release of the Sloan Digital Sky Survey all broad-line active galaxies with masses <2 × 106 M☉. BHs in this mass regime provide unique tests of the relationship between BHs and galaxies, since their late-type galaxy hosts do not necessarily contain classical bulges. Furthermore, they provide observational analogs of primordial seed BHs and are expected, when merging, to provide strong gravitational signals for future detectors such as LISA. From our preliminary sample of 19, we have increased the total sample by an order of magnitude to 174, as well as an additional 55 (less secure) candidates. The sample has a median BH mass of ⟨MBH⟩ = 1.3 × 106 M☉, and in general the objects are radiating at high fractions of their Eddington limits. We investigate the broad spectral properties of the sample; 55 are detected by ROSAT, with soft X-ray luminosities in the range 1040 to 7 × 1043 ergs s-1. Much like the preliminary sample, these objects are predominantly radio-quiet (R ≡ f6cm/f4400Å < 10), but 11 objects are detected at 20 cm, with radio powers (1021-1023 W Hz-1) that may arise from either star formation or nuclear activity; only 1% of the sample is radio-loud. We further confirm that, with ⟨Mg⟩ = -19.3 and ⟨g - r⟩ = 0.7 mag, the host galaxies are low-mass, late-type systems. At least 40% show disklike morphologies, and the combination of host galaxy colors and higher order Balmer absorption lines indicate intermediate-age stellar populations in a subset of the sample.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/100cd1851bf97fc6cd435f0b70de266ed4c129ad

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Citations in the corpus

PS16dtm: A Tidal Disruption Event in a Narrow-line Seyfert 1 Galaxy (2017, methodology): “Moreover, the host galaxy was included in the Seyfert 1 samples of Greene & Ho (2004) and Greene & Ho (2007), which were selected based on a broad component to Hα in SDSS spectra (see Figure 1).”
Nuclear Activity in Nearby Galaxies (2008, methodology): “Moreover, the degree of radio-loudness scales inversely with Lbol/LEdd (Ho 2002a; Terashima & Wilson 2003b; Wang, Luo & Ho 2004; Greene, Ho & Ulvestad 2006; Panessa et al. 2007; Sikora, Stawarz & Lasota 2007; L.C. Ho, in preparation; see Figure 10b).”
RADIATIVELY INEFFICIENT ACCRETION IN NEARBY GALAXIES (2009, methodology): “4b), and similar types of low-mass AGNs have been discovered in SDSS (Greene & Ho 2004, 2007b).”
STRUCTURE AND FORMATION OF ELLIPTICAL AND SPHEROIDAL GALAXIES (2008, background): “Furthermore, BHs exist even in bulgeless 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…”
An expanded Mbh–σ diagram, and a new calibration of active galactic nuclei masses (2010, background): “If intermediate-mass black holes exist (e.g. Greene & Ho 2004, 2007), and an observational selection bias is artificially truncating data in the Mbh–σ diagram below Mbh = 106 M , then the above relation is biased.”
Black Holes in Pseudobulges and Spheroidals: A Change in the Black Hole-Bulge Scaling Relations at Low Mass (2008, methodology): “It is worth noting, however, that there are implicit constraints on the host galaxy light set by the selection process, which are discussed in detail by Greene & Ho (2007b).”
FEEDBACK FROM CENTRAL BLACK HOLES IN ELLIPTICAL GALAXIES. III. MODELS WITH BOTH RADIATIVE AND MECHANICAL FEEDBACK (2010, result): “These values compare nicely with observational estimates (e.g., Heckman et al. 2004, Greene & Ho 2007).”
The Coevolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe (2014, methodology): “A complementary probe of lower-mass SMBH in SDSS is provided by using mass estimates based on the broad emission-line width for Type 1 AGN (Greene & Ho 2007b, Dong et al. 2012, Kormendy & Ho 2013).”
THE LOW-LUMINOSITY END OF THE RADIUS–LUMINOSITY RELATIONSHIP FOR ACTIVE GALACTIC NUCLEI (2013, background): “…jets and the jet–disk connection (e.g., Sambruna et al. 2006; Tavecchio et al. 2007; Ghisellini & Tavecchio 2010), stud ies of black holes in dwarf and low-mass galaxies (e.g., Greene & Ho 2007a; Dong et al. 2007; Thornton et al. 2008), and studies of optical transients (e.g., Drake et al. 2011).”
Optical Flares from the Tidal Disruption of Stars by Massive Black Holes (2009, background): “…space density of 105 − 106M⊙ BHs and the stellar density profiles in the galaxies they inhabit are only moderately well-constrained at present (e.g., Greene & Ho 2007), as is the role of tidal disruption in growing these BHs. Optical searches for tidal flares should thus prove to be a powerful…”
Observational evidence for intermediate-mass black holes (2017, methodology): “Similar results were found by Ludlam et al. (2015), who studied XMM-Newton data of 14 low-mass AGN drawn from the Greene & Ho (2007a) sample and found that only two of them show evidence for significant absorption.”
THE NGC 404 NUCLEUS: STAR CLUSTER AND POSSIBLE INTERMEDIATE-MASS BLACK HOLE (2010, methodology): “A reverberation mapping mass of the BH in nearby Seyfert 1 galaxy NGC 4395 (Peterson et al. 2005), and indirect mass measurements in other low mass Seyfert 1 galaxies (e.g. Greene & Ho 2007) provide additional evidence for the presence of IMBHs at the centers of lower mass galaxies.”
RELATIONS BETWEEN CENTRAL BLACK HOLE MASS AND TOTAL GALAXY STELLAR MASS IN THE LOCAL UNIVERSE (2015, methodology): “This subsample includes the wellstudied dwarf disk galaxy NGC 4395 hosting a Seyfert 1 nucleus (Filippenko & Sargent 1989; Filippenko & Ho 2003), two objects from the Greene & Ho (2007a) sample of low-mass BHs, and the dwarf disk galaxy presented in Dong et al. (2007).”
A ∼50,000 M⊙ SOLAR MASS BLACK HOLE IN THE NUCLEUS OF RGG 118 (2015, methodology): “The first systematic searches for low-mass BHs were done by Greene & Ho (2004, 2007), which searched the Sloan Digital Sky Survey (SDSS) for galaxies with broad Hα emission indicating AGN with masses below 2 × 106M .”
DWARF GALAXIES WITH OPTICAL SIGNATURES OF ACTIVE MASSIVE BLACK HOLES (2013, methodology): “106.5 M ), the line-widths can be just hundreds of km s−1 (e.g., Filippenko & Ho 2003; Greene & Ho 2007a).”