Black Hole Mass Of NGC Research Articles

A compact symmetric ejection from the low mass AGN in the LINER galaxy NGC 4293

ABSTRACT We conducted a Very Long Baseline Array (VLBA) observation of the low mass active galactic nucleus (AGN) in galaxy NGC 4293 (z = 0.003). The object is associated with a low-ionization nuclear emission-line region (LINER). Its black hole mass is estimated as ∼105 or ${\sim}10^7 \, \mathrm{M}_\odot$. The VLBA 1.5 GHz image shows an inverse symmetric structure with two discrete radio blobs separated by an angular distance of ∼120 mas, corresponding to ∼7 parsec. Furthermore, its integrated radio spectrum has a turnover at the frequency of ∼0.44 GHz. Based on the compactness and spectrum, the nuclear radio source in NGC 4293 belongs to a sample of (megahertz) peaked spectrum (PS/MPS) radio sources with compact symmetric morphologies. NGC 4293 has 1.4 GHz radio power of only ${\sim}10^{20}\, \mathrm{W\, Hz^{-1}}$ with the VLBA observation, which is consistent with local AGNs but lower than the current PS samples. One of the two blobs has a steep radio spectrum α = −0.62 ± 0.08 (Sν ∝ ν+α), while the other one has an inverted spectrum α = 0.32 ± 0.10. The VLBA 1.5 GHz luminosity ratio of the two blobs is 3.23 and both blobs show lateral-flowing structures where the hotspots reside at the edge of each radio lobe. This can be explained as jet interactions with dense circumnuclear medium. We estimate the black hole mass of NGC 4293 through the Fundamental Plane of black hole activity, which constrains the black hole mass to be ${\lesssim}10^6\, \mathrm{M}_\odot$. It supports that the object is a low-mass AGN and a potential candidate for accreting and ejecting IMBHs.

The Broad Line Region and Black Hole Mass of NGC 4151

We present a reanalysis of reverberation mapping data from 2005 for the Seyfert galaxy NGC 4151, supplemented with additional data from the literature to constrain the continuum variations over a significantly longer baseline than the original monitoring program. Modeling of the continuum light curve and the velocity-resolved variations across the Hβ emission line constrains the geometry and kinematics of the broad line region (BLR). The BLR is well described by a very thick disk with similar opening angle (θ o ≈ 57°) and inclination angle (θ i ≈ 58°), suggesting that our sight line toward the innermost central engine skims just above the surface of the BLR. The inclination is consistent with constraints from geometric modeling of the narrow-line region, and the similarity between the inclination and opening angles is intriguing given previous studies of NGC 4151 that suggest BLR gas has been observed temporarily eclipsing the X-ray source. The BLR kinematics are dominated by eccentric bound orbits, with ∼10% of the orbits preferring near-circular motions. With the BLR geometry and kinematics constrained, the models provide an independent and direct black hole mass measurement of or M ⊙, which is in good agreement with mass measurements from stellar dynamical modeling and gas dynamical modeling. NGC 4151 is one of the few nearby broad-lined Seyferts where the black hole mass may be measured via multiple independent techniques, and it provides an important test case for investigating potential systematics that could affect the black hole mass scales used in the local universe and for high-redshift quasars.

The Black Hole Mass of NGC 4151 from Stellar Dynamical Modeling

Abstract The mass of a supermassive black hole (M BH) is a fundamental property that can be obtained through observational methods. Constraining M BH through multiple methods for an individual galaxy is important for verifying the accuracy of different techniques and for investigating the assumptions inherent in each method. However, there exist only a few galaxies where multiple M BH measurement techniques can be applied. NGC 4151 is one of these rare galaxies for which multiple methods can be used: stellar and gas dynamical modeling because of its proximity (D = 15.8 ± 0.4 Mpc from Cepheids), and reverberation mapping because of its active accretion. In this work, we reanalyzed H-band integral field spectroscopy of the nucleus of NGC 4151 from Gemini NIFS, improving the analysis at several key steps. We then constructed a wide range of axisymmetric dynamical models with the new orbit-superposition code Forstand. One of our primary goals is to quantify the systematic uncertainties in M BH arising from different combinations of the deprojected density profile, inclination, intrinsic flattening, and mass-to-light ratio. As a consequence of uncertainties on the stellar luminosity profile arising from the presence of the active galactic nucleus, our constraints on M BH are rather weak. Models with a steep central cusp are consistent with no black hole; however, in models with more moderate cusps, the black hole mass lies within the range of 0.25 × 107 M ⊙ ≲ M BH ≲ 3 × 107 M ⊙. This measurement is somewhat smaller than the earlier analysis presented by Onken et al. but agrees with previous M BH values from gas dynamical modeling and reverberation mapping. Future dynamical modeling of reverberation data, as well as IFU observations with JWST, will aid in further constraining the mass of the central supermassive black hole in NGC 4151.

Reverberation Mapping of Changing-look Active Galactic Nucleus NGC 3516

Abstract The changes of broad emission lines should be a crucial issue in understanding the physical properties of changing-look active galactic nuclei (CL-AGNs). Here we present the results of an intensive and homogeneous 6 month long reverberation mapping (RM) monitoring campaign during a low-activity state of the CL-AGN Seyfert galaxy NGC 3516. Photometric and spectroscopic monitoring was carried out during 2018–2019 with the Lijiang 2.4 m telescope. The sampling is 2 days in most nights, and the average sampling is ∼3 days. The rest-frame time lags of Hα and Hβ are and days, respectively. From an rms Hβ line dispersion of σ line = 1713.3 ± 46.7 km s−1 and a virial factor of f σ = 5.5, the central black hole mass of NGC 3516 is estimated to be , which is in agreement with previous estimates. The velocity-resolved delays show that the time lags increase toward negative velocity for both Hα and Hβ. The velocity-resolved RM of Hα is done for the first time. These RM results are consistent with other observations before the spectral-type change, indicating a basically constant broad-line region structure during the CL process. The CL model of changes of accretion rate seems to be favored by long-term Hβ variability and RM observations of NGC 3516.

A Comparison of Supermassive Black Hole Mass of NGC 4151 Using Different Methods

We found a new value of supermassive black hole (SMBH) mass in the middle of type 1 Seyfert, NGC 4151 galaxy. In this Study, the image of NGC 4151 galaxy was deprojected to face-on, using spiral galaxy of face-on, and applied IRAF to calculate the ellipticity and position angle of major-axis. A two-dimensional (2D) Fast Fourier Transform (FFT) applied to the deprojected image to calculate the spiral arm of NGC 4151 galaxy, and, in that way, find a central mass AGN 4151 galaxy. We compared our results of the mass of SMBH in in the center of NGC 4151 galaxy with the mass of SMBH calculated using different methods ((direct method: stellar dynamics, gas dynamics, reverberation mapping), and indirect method: MBH-σ*, MBH-Vrot, MBH-n, MBH-Lbulge, and MBH-P correlations). We concluded that the results of mass for these methods are in agreement with the estimated ones, i.e. using direct methods.

WISDOM project – IV. A molecular gas dynamical measurement of the supermassive black hole mass in NGC 524

ABSTRACT We present high angular resolution (0.3 arcsec or $37\, \mathrm{pc}$) Atacama Large Millimeter/submillimeter Array observations of the CO(2–1) line emission from a central disc in the early-type galaxy NGC 524. This disc is shown to be dynamically relaxed, exhibiting ordered rotation about a compact $1.3\, \mathrm{mm}$ continuum source, which we identify as emission from an active supermassive black hole (SMBH). There is a hole at the centre of the disc slightly larger than the SMBH sphere of influence. An azimuthal distortion of the observed velocity field is found to be due to either a position angle warp or radial gas flow over the inner 2${^{\prime\prime}_{.}}$5. By forward-modelling the observations, we obtain an estimate of the SMBH mass of $4.0^{+3.5}_{-2.0}\times 10^8\,$ M⊙, where the uncertainties are at the 3σ level. The uncertainties are dominated by the poorly constrained inclination and the stellar mass-to-light ratio of this galaxy, and our measurement is consistent with the established correlation between SMBH mass and stellar velocity dispersion. Our result is roughly half that of the previous stellar dynamical measurement, but is consistent within the uncertainties of both. We also present and apply a new tool for modelling complex molecular gas distributions.

Scaling of X-ray spectral properties of a black hole in the Seyfert 1 galaxy NGC7469

We present our analysis of X-ray spectral properties observed from the Seyfert 1 galactic nucleus NGC 7469 using theRossiX-ray Timing Explorer (RXTE) and Advanced Satellite for Cosmology and Astrophysics mission (ASCA) observations. We demonstrate strong observational evidence that NGC 7469 undergoes spectral transitions from the low hard state (LHS) to the intermediate state (IS) during these observations. The RXTE observations (1996–2009) show that the source was in the IS ∼75% of the time only ∼25% of the time in the LHS. The spectra of NGC 7469 are well fitted by the so-called bulk motion Comptonization (BMC) model for all spectral states. We have established the photon index (Γ) saturation level, Γsat= 2.1 ± 0.1, in the Γ versus mass accretion rate,Ṁcorrelation. This Γ –Ṁcorrelation allows us to estimate the black hole (BH) mass in NGC 7469 to beMBH≥ 3 × 106M⊙assuming the distance to NGC 7469 of 70 Mpc. For this BH mass estimate, we use the scaling method taking Galactic BHs, GRO J1655–40, Cyg X–1, and an extragalactic BH source, NGC 4051 as reference sources. The Γ versusṀcorrelation revealed in NGC 7469 is similar to those in a number of Galactic and extragalactic BHs and it clearly shows the correlation along with the strong Γ saturation at ≈2.1. This is robust observational evidence for the presence of a BH in NGC 7469. We also find that the seed (disk) photon temperatures are quite low, of the order of 140–200 eV, which are consistent with a high BH mass in NGC 7469 that is more than 3 × 106solar masses.

NGC 4051: Black hole mass and photon index-mass accretion rate correlation

We present a discovery of the correlation between the X-ray spectral (photon) index and mass accretion rate observed in an active galactic nucleus, NGC 4051. We analyzed spectral transition episodes observed in NGC 4051 usingXMM-Newton,Suzakuand RXTE. We applied a scaling technique for a black hole (BH) mass evaluation which uses a correlation between the photon index and normalization of the seed (disk) component, which is proportional to a mass accretion rate. We developed an analytical model that shows the spectral (photon) index of the BH emergent spectrum undergoes an evolution from lower to higher values depending on a mass accretion rate in the accretion disk. We considered Cygnus X-1 and GRO J1550–564 as reference sources for which distances, inclination angles and the BH masses are evaluated by dynamical measurements. Application of the scaling technique for the photon index−mass accretion rate correlation provides an estimate of the black hole mass in NGC 4051 to be more than 6 × 105solar masses.

WISDOM Project – II. Molecular gas measurement of the supermassive black hole mass in NGC 4697

As part of the mm-Wave Interferometric Survey of Dark Object Masses (WISDOM) project, we present an estimate of the mass of the supermassive black hole (SMBH) in the nearby fast-rotating early-type galaxy NGC4697. This estimate is based on Atacama Large Millimeter/submillimeter Array (ALMA) cycle-3 observations of the 12CO(2-1) emission line with a linear resolution of 29 pc (0.53"). We find that NGC4697 hosts a small relaxed central molecular gas disc with a mass of 1.6x10^7 Msun, co-spatial with the obscuring dust disc visible in optical Hubble Space Telescope (HST) imaging. We also resolve thermal 1mm continuum emission from the dust in this disc. NGC4697 is found to have a very low molecular gas velocity dispersion, $\sigma_{gas}=1.65^{+0.68}_{-0.65}$ km/s. This seems to be partially because the giant molecular cloud mass function is not fully sampled, but other mechanisms such as chemical differentiation in a hard radiation field or morphological quenching also seem to be required. We detect a Keplerian increase of the rotation of the molecular gas in the very centre of NGC4697, and use forward modelling of the ALMA data cube in a Bayesian framework with the KINematic Molecular Simulation (KinMS) code to estimate a SMBH mass of ($1.3_{-0.17}^{+0.18})\times10^8$ Msun and an i-band mass-to-light ratio of $2.14_{-0.05}^{+0.04}$ Msun/Lsun (at the 99% confidence level). Our estimate of the SMBH mass is entirely consistent with previous measurements from stellar kinematics. This increases confidence in the growing number of SMBH mass estimates being obtained in the ALMA era.

Improved Dynamical Constraints on the Mass of the Central Black Hole in NGC 404

Abstract We explore the nucleus of the nearby 109 M ⊙ early-type galaxy, NGC 404, using Hubble Space Telescope (HST)/STIS spectroscopy and WFC3 imaging. We first present evidence for nuclear variability in UV, optical, and infrared filters over a time period of 15 years. This variability adds to the already substantial evidence for an accreting black hole at the center of NGC 404. We then redetermine the dynamical black hole mass in NGC 404 including modeling of the nuclear stellar populations. We combine HST/STIS spectroscopy with WFC3 images to create a local color–M/L relation derived from stellar population modeling of the STIS data. We then use this to create a mass model for the nuclear region. We use Jeans modeling to fit this mass model to adaptive optics stellar kinematic observations from Gemini/NIFS. From our stellar dynamical modeling, we find a 3σ upper limit on the black hole mass of 1.5 × 10 5 M ⊙ . Given the accretion evidence for a black hole, this upper limit makes NGC 404 the lowest mass central black hole with dynamical mass constraints. We find that the kinematics of H2 emission line gas show evidence for non-gravitational motions preventing the use of gas dynamical modeling to constrain the black hole mass. Our stellar population modeling also reveals that the central, counter-rotating region of the nuclear cluster is dominated by ∼1 Gyr old populations.

The central black hole mass of the high-σ but low-bulge-luminosity lenticular galaxy NGC 1332★

The masses of the most massive supermassive black holes (SMBHs) predicted by the M_BH-sigma and M_BH-luminosity relations appear to be in conflict. Which of the two relations is the more fundamental one remains an open question. NGC 1332 is an excellent example that represents the regime of conflict. It is a massive lenticular galaxy which has a bulge with a high velocity dispersion sigma of ~320 km/s; bulge--disc decomposition suggests that only 44% of the total light comes from the bulge. The M_BH-sigma and the M_BH-luminosity predictions for the central black hole mass of NGC 1332 differ by almost an order of magnitude. We present a stellar dynamical measurement of the SMBH mass using an axisymmetric orbit superposition method. Our SINFONI integral-field unit (IFU) observations of NGC 1332 resolve the SMBH's sphere of influence which has a diameter of ~0.76 arcsec. The sigma inside 0.2 arcsec reaches ~400 km/s. The IFU data allow us to increase the statistical significance of our results by modelling each of the four quadrants separately. We measure a SMBH mass of (1.45 \pm 0.20) x 10^9 M_sun with a bulge mass-to-light ratio of 7.08 \pm 0.39 in the R-band. With this mass, the SMBH of NGC 1332 is offset from the M_BH-luminosity relation by a full order of magnitude but is consistent with the M_BH-sigma relation.

The Black Hole Mass of NGC 4151: Comparison of Reverberation Mapping and Stellar Dynamical Measurements

We present a stellar dynamical estimate of the black hole (BH) mass in the Seyfert 1 galaxy, NGC 4151. We analyze ground-based spectroscopy as well as imaging data from the ground and space, and we construct 3-integral axisymmetric models in order to constrain the BH mass and mass-to-light ratio. The dynamical models depend on the assumed inclination of the kinematic symmetry axis of the stellar bulge. In the case where the bulge is assumed to be viewed edge-on, the kinematical data give only an upper limit to the mass of the BH of ~4e7 M_sun (1 sigma). If the bulge kinematic axis is assumed to have the same inclination as the symmetry axis of the large-scale galaxy disk (i.e., 23 degrees relative to the line of sight), a best-fit dynamical mass between 4-5e7 M_sun is obtained. However, because of the poor quality of the fit when the bulge is assumed to be inclined (as determined by the noisiness of the chi^2 surface and its minimum value), and because we lack spectroscopic data that clearly resolves the BH sphere of influence, we consider our measurements to be tentative estimates of the dynamical BH mass. With this preliminary result, NGC 4151 is now among the small sample of galaxies in which the BH mass has been constrained from two independent techniques, and the mass values we find for both bulge inclinations are in reasonable agreement with the recent estimate from reverberation mapping (4.57[+0.57/-0.47]e7 M_sun) published by Bentz et al.

A Variability Study of the Seyfert 2 Galaxy NGC 6300 withXMM‐Newton

We present the results of timing analysis of the XMM-Newton observation of the Seyfert 2 galaxy NGC 6300. The hard X-ray spectrum above 2 keV consists of a Compton-thin absorbed power law, as is often seen in Seyfert 2 galaxies. We clearly detected rapid time variability on a timescale of about 1000 s from the light curve above 2 keV. The excess variance of the time variability (σ) is calculated to be ~0.12, and the periodogram of the light curve is well represented by a power-law function with a slope of 1.75. In contrast to previous results from Seyfert 2 nuclei, these variability characteristics are consistent with those of Seyfert 1 galaxies. This consistency suggests that NGC 6300 has a black hole mass and accretion properties similar to Seyfert 1 galaxies. Using the relation between time variability and central black hole mass by Hayashida et al., the black hole mass of NGC 6300 is estimated to be ~2.8 × 105 M☉. Taking the uncertainty of this method into account, the black hole mass is less than 107 M☉. Taking the bolometric luminosity of 3.3 × 1043 ergs s-1 into consideration, this yields an accretion rate of >0.03 of the Eddington value, comparable to estimates from Seyfert 1 galaxies using this method. The time variability analysis suggests that NGC 6300 actually has a Seyfert 1 nucleus obscured by thick matter and more generally provides a new pillar of support for the unified model of Seyfert galaxies based on obscuration.

Complex X-ray spectral behaviour of NGC 4051 in the low flux state

The narrow-line Seyfert 1 galaxy, NGC 4051, was observed in one of its prolonged low flux states by XMM-Newton in 2002 November. Here we present the results of an analysis of the European Photon Imaging Camera (EPIC) pn data obtained during the observation. Within the low state, the source shows complex spectral variability which cannot easily be explained by any simple model. However, by making a 'flux-flux' plot which combines the low state data with data obtained during a normal flux state, we demonstrate that the extremely hard spectrum observed above 2 keV results from a continuation of the spectral variability seen in the normal state, which is caused by spectral pivoting of the power-law continuum. The pivoting power law appears to be attached to a Comptonized thermal component of variable flux (blackbody temperature kT similar to 0.1 keV, consistent with the small black hole mass in NGC 4051) which dominates the soft X-ray band in the low state, and is probably the source of seed photons for Comptonization. Additional constant thermal and reflection components, together with absorption by ionized gas, seem to be required to complete the picture and explain the complex X-ray spectral variability seen in the low state of NGC 4051.

Evidence for an intermediate-mass black hole and a multi-zone warm absorber in NGC 4395

We report on the results of an analysis in the X-ray band of a recent long ASCA observation of NGC 4395, the most variable low-luminosity active galactic nucleus known. A relativistically broadened iron line at ∼6.4 keV is clearly resolved in the time-averaged spectrum, with an equivalent width of 310 + 7 0 - 9 0 eV. Time-resolved spectral analysis of the heavily absorbed soft X-ray band confirms the existence of a variable, multi-zone warm absorber in this source, as proposed in a previous analysis of a shorter ASCA observation. The light curve of the source is wildly variable on time-scales of hours or less, and a factor of nearly 10 change in count rate was recorded in a period of less than 2000 s. The long observation and variability of the source allowed the power density spectrum (PDS) to be constructed to an unprecedented level of detail. There is evidence for a break in the PDS from a slope of a ∼ 1 to a ∼ 1.8 at a frequency of around 3 x 10 - 4 Hz. The central black hole mass of NGC 4395 is estimated to be approximately 10 4 -10 5 M O . using the break in the PDS, a result consistent with previous analyses using optical and kinematical techniques.

Estimate of the black-hole mass in NGC 6814 from a relativistic accretion disk scenario

By using a fully relativistic model for the spectral line produced by a Keplerian disk orbiting a Schwarzschild black hole, we study the temporal behaviour of the line intensity in response to a continuum variation at an extended central source. We compare our results with the observed properties of the Seyfert galaxy NGC 6814, whose X-ray flux has been observed to decrease by a factor of two in ≈ 50 s, while the iron line intensity variations lag continuum variations by 250 s, at the most. Taking the stationary values of the iron line centroid energy and width, and assuming that the line comes from high-ionisation stages of iron (as several indications suggest) we derive that the inner radius of the line-emitting region is between 6 and 30rg (rg=GM/c2), the inclination is ≤40°, while the mass of the central object is constrained to 8·104L43<M<3.9·106M⊙(L43 is the accretion luminosity in units of 1043 erg s−1).