Abstract
We analyse the environmental properties of 370 local early-type galaxies (ETGs) in the MASSIVE and ATLAS3D surveys, two complementary volume-limited integral-field spectroscopic (IFS) galaxy ...surveys spanning absolute K-band magnitude − 21.5 ≳ MK
≳ −26.6, or stellar mass
$8\times 10^{9} \lesssim M_* \lesssim 2\times 10^{12}\,\text{M}_{\odot }$
. We find these galaxies to reside in a diverse range of environments measured by four methods: group membership (whether a galaxy is a brightest group/cluster galaxy, satellite or isolated), halo mass, large-scale mass density (measured over a few Mpc) and local mass density (measured within the Nth neighbour). The spatially resolved IFS stellar kinematics provide robust measurements of the spin parameter λe and enable us to examine the relationship among λe, M
* and galaxy environment. We find a strong correlation between λe and M
*, where the average λe decreases from ∼0.4 to below 0.1 with increasing mass, and the fraction of slow rotators f
slow increase from ∼10 to 90 per cent. We show for the first time that at fixed M
*, there are almost no trends between galaxy spin and environment; the apparent kinematic morphology–density relation for ETGs is therefore primarily driven by M
* and is accounted for by the joint correlations between M
* and spin, and between M
* and environment. A possible exception is that the increased f
slow at high local density is slightly more than expected based only on these joint correlations. Our results suggest that the physical processes responsible for building up the present-day stellar masses of massive galaxies are also very efficient at reducing their spin, in any environment.
The supermassive black hole of M87 is one of the most massive black holes known and has been the subject of several stellar and gas-dynamical mass measurements; however, the most recent revision to ...the stellar-dynamical black hole mass measurement is a factor of about two larger than the previous gas-dynamical determinations. Here, we apply comprehensive gas-dynamical models that include the propagation of emission-line profiles through the telescope and spectrograph optics to new Space Telescope Imaging Spectrograph observations from the Hubble Space Telescope. Unlike the previous gas-dynamical studies of M87, we map out the complete kinematic structure of the emission-line disk within {approx}40 pc from the nucleus, and find that a small amount of velocity dispersion internal to the gas disk is required to match the observed line widths. We examine a scenario in which the intrinsic velocity dispersion provides dynamical support to the disk, and determine that the inferred black hole mass increases by only 6%. Incorporating this effect into the error budget, we ultimately measure a mass of M{sub BH}= (3.5{sup +0.9}{sub -0.7}) Multiplication-Sign 10{sup 9} M{sub sun} (68% confidence). Our gas-dynamical black hole mass continues to differ from the most recent stellar-dynamical mass by a factor of two, underscoring the need for carrying out more cross-checks between the two main black hole mass measurement methods.
We present ∼0.″10 resolution Atacama Large Millimeter/submillimeter Array (ALMA) CO(2−1) imaging of the arcsecond-scale (r ≈ 150 pc) dusty molecular disk in the giant elliptical galaxy NGC 3258. The ...data provide unprecedented resolution of the cold gas disk kinematics within the dynamical sphere of influence of a supermassive black hole (BH), revealing a quasi-Keplerian central increase in projected rotation speed rising from 280 km s−1 at the disk’s outer edge to >400 km s−1 near the disk center. We construct dynamical models for the rotating disk and fit beam-smeared model CO line profiles directly to the ALMA data cube. Our models incorporate both flat and tilted-ring disks that provide a better fit of the mildly warped structure in NGC 3258. We show that the exceptional angular resolution of the ALMA data makes it possible to infer the host galaxy’s mass profile within r = 150 pc solely from the ALMA CO kinematics, without relying on optical or near-infrared imaging data to determine the stellar mass profile. Our model therefore circumvents any uncertainty in the BH mass that would result from the substantial dust extinction in the galaxy’s central region. The best model fit yields \({M}_{\mathrm{BH}}=2.249\times {10}^{9}\) \({M}_{\odot }\), with a statistical model-fitting uncertainty of just 0.18% and systematic uncertainties of 0.62% from various aspects of the model construction and 12% from uncertainty in the distance to NGC 3258. This observation demonstrates the full potential of ALMA for carrying out highly precise measurements of \({M}_{\mathrm{BH}}\) in early-type galaxies containing circumnuclear gas disks.
We present the detection of supermassive black holes (BHs) in two Virgo ultracompact dwarf galaxies (UCDs), VUCD3 and M59cO. We use adaptive optics assisted data from the Gemini/NIFS instrument to ...derive radial velocity dispersion profiles for both objects. Mass models for the two UCDs are created using multi-band Hubble Space Telescope imaging, including the modeling of mild color gradients seen in both objects. We then find a best-fit stellar mass-to-light ratio (M/L) and BH mass by combining the kinematic data and the deprojected stellar mass profile using Jeans Anisotropic Models. Assuming axisymmetric isotropic Jeans models, we detect BHs in both objects with masses of 4.4 − 3.0 + 2.5 × 10 6 M in VUCD3 and 5.8 − 2.8 + 2.5 × 10 6 M in M59cO (3 uncertainties). The BH mass is degenerate with the anisotropy parameter, β z ; for the data to be consistent with no BH requires β z = 0.4 and β z = 0.6 for VUCD3 and M59cO, respectively. Comparing these values with nuclear star clusters shows that, while it is possible that these UCDs are highly radially anisotropic, it seems unlikely. These detections constitute the second and third UCDs known to host supermassive BHs. They both have a high fraction of their total mass in their BH; ∼13% for VUCD3 and ∼18% for M59cO. They also have low best-fit stellar M/Ls, supporting the proposed scenario that most massive UCDs host high-mass fraction BHs. The properties of the BHs and UCDs are consistent with both objects being the tidally stripped remnants of ∼ 10 9 M galaxies.
The Shocking Power Sources of LINERs Molina, Mallory; Eracleous, Michael; Barth, Aaron J. ...
The Astrophysical journal,
09/2018, Letnik:
864, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
The majority of low-ionization nuclear emission-line regions (LINERs) harbor supermassive black holes with very low accretion rates. However, the accretion flows do not produce enough ...ionizing photons to power the emission lines emitted on scales of ∼100 pc, and therefore additional sources of power are required. We present and analyze
Hubble Space Telescope
spectra of three nearby luminous LINERs that are spatially resolved on scales of ≲9 pc. The targets have multiple indicators of an accreting black hole, as well as a deficient ionizing photon budget. We measure diagnostic emission line ratios as a function of distance from the nucleus and compare them to models for different excitation mechanisms: shocks, photoionization by the accreting black hole, and photoionization by young or old hot stars. We also consider the kinematics of the line-emitting gas, as revealed by the widths and shifts of the emission lines. We conclude that, in LINERs with low-luminosity active nuclei, shocks by jets or other outflows are crucial in exciting the gas in and around the nucleus, as suggested by other authors. The physical model that best describes our targets comprises a low-luminosity, accretion-powered active nucleus that photoionizes the gas within ∼20 pc of the galaxy center, and shock excitation of the gas at larger distances.
We examine the internal properties of the most massive ultracompact dwarf galaxy (UCD), M59-UCD3, by combining adaptive-optics-assisted near-IR integral field spectroscopy from Gemini/NIFS and Hubble ...Space Telescope (HST) imaging. We use the multiband HST imaging to create a mass model that suggests and accounts for the presence of multiple stellar populations and structural components. We combine these mass models with kinematics measurements from Gemini/NIFS to find a best-fit stellar mass-to-light ratio (M/L) and black hole (BH) mass using Jeans anisotropic models (JAMs), axisymmetric Schwarzschild models, and triaxial Schwarzschild models. The best-fit parameters in the JAM and axisymmetric Schwarzschild models have BHs between 2.5 and 5.9 million solar masses. The triaxial Schwarzschild models point toward a similar BH mass but show a minimum χ2 at a BH mass of ∼0. Models with a BH in all three techniques provide better fits to the central Vrms profiles, and thus we estimate the BH mass to be 4.2 − 1.7 + 2.1 × 10 6 M (estimated 1 uncertainties). We also present deep radio imaging of M59-UCD3 and two other UCDs in Virgo with dynamical BH mass measurements, and we compare these to X-ray measurements to check for consistency with the fundamental plane of BH accretion. We detect faint radio emission in M59cO but find only upper limits for M60-UCD1 and M59-UCD3 despite X-ray detections in both these sources. The BH mass and nuclear light profile of M59-UCD3 suggest that it is the tidally stripped remnant of a ∼109-1010 M galaxy.
We present models of the Hβ-emitting broad-line region (BLR) in seven Seyfert 1 galaxies from the Lick AGN Monitoring Project 2011 sample, drawing inferences on the BLR structure and dynamics as well ...as the mass of the central supermassive black hole. We find that the BLR is generally a thick disk, viewed close to face-on, with preferential emission back toward the ionizing source. The dynamics in our sample range from near-circular elliptical orbits to inflowing or outflowing trajectories. We measure black hole masses of for PG 1310−108, for Mrk 50, for Mrk 141, for Mrk 279, for Mrk 1511, for NGC 4593, and for Zw 229−015. We use these black hole mass measurements along with cross-correlation time lags and line widths to recover the scale factor f used in traditional reverberation mapping measurements. Combining our results with other studies that use this modeling technique, which brings our sample size to 16, we calculate a scale factor that can be used for measuring black hole masses in other reverberation mapping campaigns. When using the root-mean-square (rms) spectrum and using the line dispersion to measure the line width, we find pred = 0.57 0.19. Finally, we search for correlations between f and other AGN and BLR parameters and find marginal evidence that f is correlated with MBH and the BLR inclination angle, but no significant evidence of a correlation with the AGN luminosity or Eddington ratio.
Abstract
We measure the radial profiles of the stellar velocity dispersions, σ(R), for 90 early-type galaxies (ETGs) in the MASSIVE survey, a volume-limited integral-field spectroscopic (IFS) galaxy ...survey targeting all northern-sky ETGs with absolute K-band magnitude MK < −25.3 mag, or stellar mass M* ≳ 4 × 1011M⊙, within 108 Mpc. Our wide-field 107 arcsec × 107 arcsec IFS data cover radii as large as 40 kpc, for which we quantify separately the inner (2 kpc) and outer (20 kpc) logarithmic slopes γinner and γouter of σ(R). While γinner is mostly negative, of the 56 galaxies with sufficient radial coverage to determine γouter we find 36 per cent to have rising outer dispersion profiles, 30 per cent to be flat within the uncertainties and 34 per cent to be falling. The fraction of galaxies with rising outer profiles increases with M* and in denser galaxy environment, with 10 of the 11 most massive galaxies in our sample having flat or rising dispersion profiles. The strongest environmental correlations are with local density and halo mass, but a weaker correlation with large-scale density also exists. The average γouter is similar for brightest group galaxies, satellites and isolated galaxies in our sample. We find a clear positive correlation between the gradients of the outer dispersion profile and the gradients of the velocity kurtosis h4. Altogether, our kinematic results suggest that the increasing fraction of rising dispersion profiles in the most massive ETGs are caused (at least in part) by variations in the total mass profiles rather than in the velocity anisotropy alone.
Abstract
The three-dimensional intrinsic shape of a galaxy and the mass of the central supermassive black hole provide key insight into the galaxy’s growth history over cosmic time. Standard ...assumptions of a spherical or axisymmetric shape can be simplistic and can bias the black hole mass inferred from the motions of stars within a galaxy. Here, we present spatially resolved stellar kinematics of M87 over a two-dimensional 250″ × 300″ contiguous field covering a radial range of 50 pc–12 kpc from integral-field spectroscopic observations at the Keck II Telescope. From about 5 kpc and outward, we detect a prominent 25 km s
−1
rotational pattern, in which the kinematic axis (connecting the maximal receding and approaching velocities) is 40° misaligned with the photometric major axis of M87. The rotational amplitude and misalignment angle both decrease in the inner 5 kpc. Such misaligned and twisted velocity fields are a hallmark of triaxiality, indicating that M87 is not an axisymmetrically shaped galaxy. Triaxial Schwarzschild orbit modeling with more than 4000 observational constraints enabled us to determine simultaneously the shape and mass parameters. The models incorporate a radially declining profile for the stellar mass-to-light ratio suggested by stellar population studies. We find that M87 is strongly triaxial, with ratios of
p
= 0.845 for the middle-to-long principal axes and
q
= 0.722 for the short-to-long principal axes, and determine the black hole mass to be
(
5.37
−
0.25
+
0.37
±
0.22
)
×
10
9
M
⊙
, where the second error indicates the systematic uncertainty associated with the distance to M87.
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