DWARF GALAXIES WITH OPTICAL SIGNATURES OF ACTIVE MASSIVE BLACK HOLES

By A. Reines, Jenny E. Greene, M. Geha. 2013

284 citations recorded by the source corpus.

We present a sample of 151 dwarf galaxies (108.5 ≲ M⋆ ≲ 109.5 M☉) that exhibit optical spectroscopic signatures of accreting massive black holes (BHs), increasing the number of known active galaxies in this stellar-mass range by more than an order of magnitude. Utilizing data from the Sloan Digital Sky Survey Data Release 8 and stellar masses from the NASA-Sloan Atlas, we have systematically searched for active BHs in ∼25,000 emission-line galaxies with stellar masses comparable to the Magellanic Clouds and redshifts z < 0.055. Using the narrow-line [O iii]/Hβ versus [N ii]/Hα diagnostic diagram, we find photoionization signatures of BH accretion in 136 galaxies, a small fraction of which also exhibit broad Hα emission. For these broad-line active galactic nucleus (AGN) candidates, we estimate BH masses using standard virial techniques and find a range of 105 ≲ MBH ≲ 106 M☉ and a median of MBH ∼ 2 × 105 M☉. We also detect broad Hα in 15 galaxies that have narrow-line ratios consistent with star-forming galaxies. Follow-up observations are required to determine if these are true type 1 AGN or if the broad Hα is from stellar processes. The median absolute magnitude of the host galaxies in our active sample is Mg = −18.1 mag, which is ∼1–2 mag fainter than previous samples of AGN hosts with low-mass BHs. This work constrains the smallest galaxies that can form a massive BH, with implications for BH feedback in low-mass galaxies and the origin of the first supermassive BH seeds.

Subfields: Astronomy and Astrophysics, Global and Planetary Change

View Paper: https://www.semanticscholar.org/paper/aac7f36ab64a615a2ee82c74edda7b774ac83af1

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Citations in the corpus

Nuclear star clusters (2009, background): “2016, 2018), as well as studies of large samples in the optical (Reines et al. 2013; Baldassare et al. 2018) and infrared (Satyapal et al.”
RELATIONS BETWEEN CENTRAL BLACK HOLE MASS AND TOTAL GALAXY STELLAR MASS IN THE LOCAL UNIVERSE (2015, methodology): “In contrast, Reines et al. (2013) focused on finding low-mass BHs that can have weak broad Hα emission in dwarf galaxies that tend to have more active star formation.”
A HIGH STELLAR VELOCITY DISPERSION AND ∼100 GLOBULAR CLUSTERS FOR THE ULTRA-DIFFUSE GALAXY DRAGONFLY 44 (2016, background): “…UDGs are “failed” galaxies that were prevented from building a normal stellar population, because of extreme feedback from supernovae and young stars (Agertz & Kravtsov 2015; Calura et al. 2015), gas stripping (Fujita 2004; Yozin & Bekki 2015), AGN feedback (Reines et al. 2013), or other effects.”
The Romulus cosmological simulations: a physical approach to the formation, dynamics and accretion models of SMBHs (2016, background): “…observed not only in massive galaxies (e.g. Gehren et al. 1984; Kormendy & Richstone 1995; Kormendy & Ho 2013) but also in small, bulge-less disk galaxies (Shields et al. 2008; Filippenko & Ho 2003) as well as dwarfs (Reines et al. 2011; Reines & Deller 2012; Reines et al. 2013; Moran et al. 2014).”
A ∼50,000 M⊙ SOLAR MASS BLACK HOLE IN THE NUCLEUS OF RGG 118 (2015, methodology): “The final equation used to estimate BH mass is given in Reines et al. (2013); we also adopt a scale factor of = 1.”
Titans of the early Universe: The Prato statement on the origin of the first supermassive black holes (2018, background): “Finally, we note that virtually all mass measurements (e.g., Greene & Ho 2004, 2007; Dong et al. 2012b; Moran et al. 2014; Reines et al. 2013; Chilingarian et al. 2018) rely on virial mass estimates based on empirical line/continuum relations for AGN in the optical part of the spectrum, under the…”
Observational evidence for intermediate-mass black holes (2017, background): “Reines et al. (2013) provide an AGN fraction for optically selected dwarf galaxies at z < 0.055 of 0.5%, a value which is not corrected for incompleteness and which is much lower than the lower limit of > 20% found by Miller et al. (2015) for dwarf early-type galaxies with Eddington ratios down to…”
Fluctuating feedback-regulated escape fraction of ionizing radiation in low-mass, high-redshift galaxies (2017, background): “Indeed, while ubiquitously found in massive galaxies, it is only recently that Reines et al. (2013) discovered that massive black holes are not infrequent in low mass galaxies.”