Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userA local baseline of the black hole mass scaling relations for active galaxies. IV. Correlations between $M_{rm BH}$ and host galaxy $sigma$, stellar mass, and luminosity
140
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The tight correlations between the mass of supermassive black holes ($M_{rm BH}$) and their host-galaxy properties have been of great interest to the astrophysical community, but a clear understanding of their origin and fundamental drivers still eludes us. The local relations for active galaxies are interesting in their own right and form the foundation for any evolutionary study over cosmic time. We present Hubble Space Telescope optical imaging of a sample of 66 local active galactic nuclei (AGNs); for 14 objects, we also obtained Gemini near-infrared images. We use state of the art methods to perform surface photometry of the AGN host galaxies, decomposing them in spheroid, disk and bar (when present) and inferring the luminosity and stellar mass of the components. We combine this information with spatially-resolved kinematics obtained at the Keck Telescopes to study the correlations between $M_{rm BH}$ (determined from single-epoch virial estimators) and host galaxy properties. The correlations are uniformly tight for our AGN sample, with intrinsic scatter 0.2-0.4 dex, smaller than or equal to that of quiescent galaxies. We find no difference between pseudo and classical bulges or barred and non-barred galaxies. We show that all the tight correlations can be simultaneously satisfied by AGN hosts in the 10$^7$-10$^9$ $M_{odot}$ regime, with data of sufficient quality. The MBH-$sigma$ relation is also in agreement with that of AGNs with $M_{rm BH}$ obtained from reverberation mapping, providing an indirect validation of single-epoch virial estimators of $M_{rm BH}$.
rate research
Read More
We create a baseline of the black hole (BH) mass (MBH) - stellar-velocity dispersion (sigma) relation for active galaxies, using a sample of 66 local (0.02<z<0.09) Seyfert-1 galaxies, selected from the Sloan Digital Sky Survey (SDSS). Analysis of SDSS images yields AGN luminosities free of host-galaxy contamination and morphological classification. 51/66 galaxies have spiral morphology. 28 bulges have Sersic index n<2 and are considered candidate pseudo bulges, with eight being definite pseudo bulges based on multiple classification criteria met. Only 4/66 galaxies show sign of interaction/merging. High signal-to-noise ratio Keck spectra provide the width of the broad Hbeta emission line free of FeII emission and stellar absorption. AGN luminosity and Hbeta line widths are used to estimate MBH. The Keck-based spatially-resolved kinematics is used to determine stellar-velocity dispersion within the spheroid effective radius. We find that sigma can vary on average by up to 40% across definitions commonly used in the literature, emphasizing the importance of using self-consistent definitions in comparisons and evolutionary studies. The MBH-sigma relation for our Seyfert-1 galaxies has the same intercept and scatter as that of reverberation-mapped AGNs as well as quiescent galaxies, consistent with the hypothesis that our single epoch MBH estimator and sample selection do not introduce significant biases. Barred galaxies, merging galaxies, and those hosting pseudo bulges do not represent outliers in the MBH-sigma relation. This is in contrast with previous work, although no firm conclusion can be drawn due to the small sample size and limited resolution of the SDSS images.
[Abridged] We investigate the nature of the relations between black hole (BH) mass ($M_{rm BH}$) and the central velocity dispersion ($sigma$) and, for core-Sersic galaxies, the size of the depleted core ($R_{rm b}$). Our sample of 144 galaxies with dynamically determined $M_{rm BH}$ encompasses 24 core-Sersic galaxies, thought to be products of gas-poor mergers, and reliably identified based on high-resolution HST imaging. For core-Sersic galaxies -- i.e., combining normal-core ($R_{rm b} < 0.5 $ kpc) and large-core galaxies ($R_{rm b} gtrsim 0.5$ kpc), we find that $M_{rm BH}$ correlates remarkably well with $R_{rm b}$ such that $M_{rm BH} propto R_{rm b}^{1.20 pm 0.14}$ (rms scatter in log $M_{rm BH}$ of $Delta_{rm rms} sim 0.29$ dex), confirming previous works on the same galaxies except three new ones. Separating the sample into Sersic, normal-core and large-core galaxies, we find that Sersic and normal-core galaxies jointly define a single log-linear $M_{rm BH}-sigma$ relation $M_{rm BH} propto sigma^{ 4.88 pm 0.29}$ with $Delta_{rm rms} sim 0.47$ dex, however, at the high-mass end large-core galaxies (four with measured $M_{rm BH}$) are offset upward from this relation by ($2.5-4) times sigma_{rm s}$, explaining the previously reported steepening of the $M_{rm BH}-sigma$ relation for massive galaxies. Large-core spheroids have magnitudes $M_{V} le -23.50$ mag, half-light radii Re $>$ 10 kpc and are extremely massive $M_{*} ge 10^{12}M_{odot}$. Furthermore, these spheroids tend to host ultramassive BHs ($M_{rm BH} ge 10^{10}M_{odot}$) tightly connected with their $R_{rm b}$ rather than $sigma$. The less popular $M_{rm BH}-R_{rm b}$ relation exhibits $sim$ 62% less scatter in log $M_{rm BH}$ than the $M_{rm BH}- sigma$ relations.
Strong scaling relations between host galaxy properties (such as stellar mass, bulge mass, luminosity, effective radius etc) and their nuclear supermassive black holes mass point towards a close co-evolution. In this work, we first review previous efforts supporting the fundamental importance of the relation between supermassive black hole mass and stellar velocity dispersion ($M_{rm BH}$-$sigma_{rm e}$). We then present further original work supporting this claim via analysis of residuals and principal component analysis applied to some among the latest compilations of local galaxy samples with dynamically measured supermassive black hole masses. We conclude with a review of the main physical scenarios in favour of the existence of a $M_{rm BH}$-$sigma_{rm e}$ relation, with a focus on momentum-driven outflows.
We present high-quality Keck/LRIS longslit spectroscopy of a pilot sample of 25 local active galaxies selected from the SDSS (0.02<z<0.1; MBH>10^7 M_sun) to study the relations between black hole mass (MBH) and host-galaxy properties. We determine stellar kinematics of the host galaxy, deriving stellar-velocity dispersion profiles and rotation curves from three spectral regions (including CaH&K, MgIb triplet, and CaII triplet). In addition, we perform surface photometry on SDSS images, using a newly developed code for joint multi-band analysis. BH masses are estimated from the width of the Hbeta emission line and the host-galaxy free 5100A AGN luminosity. Combining results from spectroscopy and imaging allows us to study four MBH scaling relations: MBH-sigma, MBH-L(sph), MBH-M(sph,*), MBH-M(sph,dyn). We find the following results. First, stellar-velocity dispersions determined from aperture spectra (e.g. SDSS fiber spectra or unresolved data from distant galaxies) can be biased, depending on aperture size, AGN contamination, and host-galaxy morphology. However, such a bias cannot explain the offset seen in the MBH-sigma relation at higher redshifts. Second, while the CaT region is the cleanest to determine stellar-velocity dispersions, both the MgIb region, corrected for FeII emission, and the CaHK region, although often swamped by the AGN powerlaw continuum and emission lines, can give results accurate to within a few percent. Third, the MBH scaling relations of our pilot sample agree in slope and scatter with those of other local active and inactive galaxies. In the next papers of the series we will quantify the scaling relations, exploiting the full sample of ~100 objects.
At the highest redshifts, z>6, several tens of luminous quasars have been detected. The search for fainter AGN, in deep X-ray surveys, has proven less successful, with few candidates to date. An extrapolation of the relationship between black hole (BH) and bulge mass would predict that the sample of z>6 galaxies host relatively massive BHs (>1e6 Msun), if one assumes that total stellar mass is a good proxy for bulge mass. At least a few of these BHs should be luminous enough to be detectable in the 4Ms CDFS. The relation between BH and stellar mass defined by local moderate-luminosity AGN in low-mass galaxies, however, has a normalization that is lower by approximately an order of magnitude compared to the BH-bulge mass relation. We explore how this scaling changes the interpretation of AGN in the high-z Universe. Despite large uncertainties, driven by those in the stellar mass function, and in the extrapolation of local relations, one can explain the current non-detection of moderate-luminosity AGN in Lyman Break Galaxies if galaxies below 1e11 Msun are characterized by the low-normalization scaling, and, even more so, if their Eddington ratio is also typical of moderate-luminosity AGN rather than luminous quasars. AGN being missed by X-ray searches due to obscuration or instrinsic X-ray weakness also remain a possibility.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
