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We investigate how the properties of massive black hole binaries influence the observed properties of core galaxies. We compare the observed trend in stellar mass deficit as a function of total stellar mass in the core galaxy with predicted trends in IllustrisTNG. We calculate mass deficits in simulated galaxies by applying subgrid, post-processing physics based on the results of literature N -body experiments. We find that the median value of the posterior distribution for the minimum binary mass ratio capable of creating a core is 0.7. For the gas mass fraction above which a core is erased, we find a median value of 0.6. Thus, low mass ratio binaries do not contribute to core formation and gas-rich mergers must lead to star formation within the nucleus, ultimately erasing the core. Such constraints have important implications for the overall massive black hole binary population, black hole–galaxy co-evolution, and the origin of the gravitational wave background. [ABSTRACT FROM AUTHOR]

We present Chandra observations of 12 galaxies that contain supermassive black holes (SMBHs) with dynamical mass measurements. Each galaxy was observed for 30 ks and resulted in a total of 68 point-source detections in the target galaxies including SMBH sources, ultraluminous X-ray sources (ULXs), and extragalactic X-ray binaries. Based on our fits of the X-ray spectra, we report fluxes, luminosities, Eddington ratios, and slope of the power-law spectrum. Normalized to the Eddington luminosity, the 2-10 keV band X-ray luminosities of the SMBH sources range from 10-8 to 10-6, and the power-law slopes are centered at ~2 with a slight trend toward steeper (softer) slopes at smaller Eddington fractions, implying a change in the physical processes responsible for their emission at low accretion rates. We find 20 ULX candidates, of which 6 are likely (>90% chance) to be true ULXs. The most promising ULX candidate has an isotropic luminosity in the 0.3-10 keV band of 1.0-0.3-0.6 x 1040 erg s-1. [ABSTRACT FROM AUTHOR]

We present Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph observations of the galaxy NGC 4382 (M85) and axisymmetric models of the galaxy to determine mass-to-light ratio (ϒV) and central black hole mass (MBH). We find ϒV = 3.74 ± 0.1 M⊙/L⊙ and MBH Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed. x 107 M⊙ at an assumed distance of 17.9 Mpc, consistent with no black hole. The upper limit, MBH < 9.6 x 107 M⊙ (2σ) or MBH < 1.4 x 108(3σ), is consistent with the current M-σ relation, which predicts MBH = 8.8 x 107 M⊙ at σe = 182 km s-1, but low for the current M-L relation, which predicts MBH = 7.8 x 108 M⊙ at LV = 8.9 x 1010 L⊙.V. HST images show the nucleus to be double, suggesting the presence of a nuclear eccentric stellar disk, analogous to the Tremaine disk in M31. This conclusion is supported by the HST velocity dispersion profile. Despite the presence of this non-axisymmetric feature and evidence of a recent merger, we conclude that the reliability of our black hole mass determination is not hindered. The inferred low black hole mass may explain the lack of nuclear activity. [ABSTRACT FROM AUTHOR]

We examine the possibility that the observed relation between black hole mass and host-galaxy stellar velocity dispersion (the M-σ relation) is biased by an observational selection effect, the difficulty of detecting a black hole whose sphere of influence is smaller than the telescope resolution. In particular, we critically investigate recent claims that the M-σ relation only represents the upper limit to a broad distribution of black hole masses in galaxies of a given velocity dispersion. We find that this hypothesis can be rejected at a high confidence level, at least for the early-type galaxies with relatively high velocity dispersions (median 268 km s-1) that comprise most of our sample. We also describe a general procedure for incorporating observational selection effects in estimates of the properties of the M-σ relation. Applying this procedure we find results that are consistent with earlier estimates that did not account for selection effects, although with larger error bars. In particular, (1) the width of the M-σ relation is not significantly increased, (2) the slope and normalization of the M-σ relation are not significantly changed, and (3) most or all luminous early-type galaxies contain central black holes at zero redshift. Our results may not apply to late-type or small galaxies, which are not well represented in our sample. [ABSTRACT FROM AUTHOR]

We have used Hubble Space Telescope (HST) images, SAURON Integral Field Spectroscopy (IFS), and adaptative optics assisted Gemini NIFS near-infrared K-band IFS to map the stellar and gas distribution, excitation and kinematics of the inner few kpc of the nearby edge-on S0 galaxy NGC 4111. The HST images map its ≈450 pc diameter dusty polar ring, with an estimated gas mass ≥107 M⊙. The NIFS data cube maps the inner 110 pc radius at ≈7 pc spatial resolution, revealing a ≈220 pc diameter polar ring in hot (2267 ± 166 K) molecular H2 1–0 S(1) gas embedded in the polar ring. The stellar velocity field shows disc-dominated kinematics along the galaxy plane both in the SAURON large scale and in the NIFS nuclear-scale data. The large-scale [O  iii ] λ5007 Å velocity field shows a superposition of two disc kinematics: one similar to that of the stars and another along the polar ring, showing non-circular motions that seem to connect with the velocity field of the nuclear H2 ring, whose kinematics indicate accelerated inflow to the nucleus. The estimated mass inflow rate is enough not only to feed an active galactic nucleus (AGN) but also to trigger circumnuclear star formation in the near future. We propose a scenario in which gas from the polar ring, which probably originated from the capture of a dwarf galaxy, is moving inwards and triggering an AGN, as supported by the local X-ray emission, which seems to be the source of the H2 1–0 S(1) excitation. The fact that we see neither near-UV nor Br γ emission suggests that the nascent AGN is still deeply buried under the optically thick dust of the polar ring. [ABSTRACT FROM AUTHOR]

We investigate the distribution of massive black holes (MBHs) in the Virgo cluster. Observations suggest that active galactic nuclei activity is widespread in massive galaxies ( M*≳ 1010 M⊙), while at lower galaxy masses star clusters are more abundant, which might imply a limited presence of central black holes in these galaxy-mass regimes. We explore if this possible threshold in MBH hosting is linked to nature, nurture or a mixture of both. The nature scenario arises naturally in hierarchical cosmologies, as MBH formation mechanisms typically are efficient in biased systems, which would later evolve into massive galaxies. Nurture, in the guise of MBH ejections following MBH mergers, provides an additional mechanism that is more effective for low mass, satellite galaxies. The combination of inefficient formation, and lower retention of MBHs, leads to the natural explanation of the distribution of compact massive objects in Virgo galaxies. If MBHs arrive to the correlation with the host mass and velocity dispersion during merger-triggered accretion episodes, sustained tidal stripping of the host galaxies creates a population of MBHs which lie above the expected scaling between the holes and their host mass, suggesting a possible environmental dependence. [ABSTRACT FROM AUTHOR]