Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userMeasuring supermassive black holes with gas kinematics - II. The LINERs IC 989, NGC 5077, and NGC 6500
84
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We present results from a kinematical study of the gas in the nucleus of a sample of three LINER galaxies, obtained from archival HST/STIS long-slit spectra. We found that, while for the elliptical galaxy NGC 5077, the observed velocity curves are consistent with gas in regular rotation around the galaxys center, this is not the case for the two remaining objects. By modeling the surface brightness distribution and rotation curve from the emission lines in NGC 5077, we found that the observed kinematics of the circumnuclear gas can be accurately reproduced by adding to the stellar mass component a black hole mass of M_bh = 6.8 (-2.8,+4.3) 10**8 M_sun (uncertainties at a 1 sigma level); the radius of its sphere of influence (R_sph ~ 0.34) is well-resolved at the HST resolution. The BH mass estimate in NGC 5077 is in fairly good agreement with both the M_bh-M_bul (with an upward scatter of ~ 0.4 dex) and M_bh-sigma correlations (with an upward scatter of 0.5 dex in the Tremaine et al. form and essentially no scatter using the Ferrarese et al. form) and provides further support for the presence of a connection between the ``residuals from the M_bh-sigma correlation and the bulge effective radius. This indicates the presence of a black holes ``fundamental plane in the sense that a combination of at least sigma and R_e drives the correlations between M_bh and host bulge properties.
rate research
Read More
We present new Space Telescope Imaging Spectrograph (STIS) observations of three spiral galaxies, NGC 4303, NGC 3310 and NGC 4258. The bright optical emission lines H$alpha$ $lambda$ $6564 AA$, [NII] $lambda$$lambda$ $6549,6585 AA$ and [SII] $lambda$$lambda$ $ 6718,6732 AA$ were used to study the kinematics of the ionized gas in the nuclear region of each galaxy with a $sim 0.07arcsec$ spatial resolution. In NGC 3310, the observed gas kinematics is well matched by a circularly rotating disk model but we are only able to set an upper limit to the BH mass which, taking into account the allowed disk inclinations, varies in the range $5.0 times 10^{6} - 4.2 times 10^{7} M_{odot}$ at the 95% confidence level. In NGC 4303 the kinematical data require the presence of a BH with mass $M_{BH}=(5.0)^{+0.87}_{-2.26}times 10^{6}M_{odot}$ (for a disk inclination $i=70$ deg).In NGC 4258, the observed kinematics require the presence of a black hole with $M_{BH}= (7.9)^{+6.2}_{-3.5} times 10^{7}M_{odot}$ ($i=60$ deg). This result is in good agreement with the published value $(3.9 pm 0.1) times 10^{7} M_{odot}$, derived from $H_{2}O$-maser observations. Our attempt at measuring BH masses in these 3 late type Sbc spiral galaxies has shown that these measurements are very challenging and at the limit of the highest spatial resolution currently available. Nonetheless our estimates are in good agreement with the scaling relations between black holes and their host spheroids suggesting that (i) they are reliable and (ii) black holes in spiral galaxies follows the same scaling relations as those in more massive early-type galaxies. A crucial test for the gas kinematical method, the correct recovery of the known BH mass in NGC 4258, has been successful. [abridged]
We present Space Telescope Imaging Spectrograph emission-line spectra of the central regions of the spiral galaxies NGC 1300 and NGC 2748. From the derived kinematics of the nuclear gas we have found evidence for central supermassive black holes in both galaxies. The estimated mass of the black hole in NGC 1300 is 6.6 (+6.3, -3.2) x 10^7 solar masses and in NGC 2748 is 4.4 (+3.5, -3.6) x 10^7 solar masses (both at the 95% confidence level). These two black hole mass estimates contribute to the poorly sampled low-mass end of the nuclear black hole mass spectrum.
We present stellar-dynamical measurements of the central supermassive black hole (SMBH) in the S0 galaxy NGC 307, using adaptive-optics IFU data from VLT-SINFONI. We investigate the effects of including dark-matter haloes as well as multiple stellar components with different mass-to-light (M/L) ratios in the dynamical modeling. Models with no halo and a single stellar component yield a relatively poor fit with a low value for the SMBH mass ($7.0 pm 1.0 times 10^{7} M_{odot}$) and a high stellar M/L ratio (K-band M/L = $1.3 pm 0.1$). Adding a halo produces a much better fit, with a significantly larger SMBH mass ($2.0 pm 0.5 times 10^{8} M_{odot}$) and a lower M/L ratio ($1.1 pm 0.1$). A model with no halo but with separate bulge and disc components produces a similarly good fit, with a slightly larger SMBH mass ($3.0 pm 0.5 times 10^{8} M_{odot}$) and an identical M/L ratio for the bulge component, though the disc M/L ratio is biased high (disc M/L $ = 1.9 pm 0.1$). Adding a halo to the two-stellar-component model results in a much more plausible disc M/L ratio of $1.0 pm 0.1$, but has only a modest effect on the SMBH mass ($2.2 pm 0.6 times 10^{8} M_{odot}$) and leaves the bulge M/L ratio unchanged. This suggests that measuring SMBH masses in disc galaxies using just a single stellar component and no halo has the same drawbacks as it does for elliptical galaxies, but also that reasonably accurate SMBH masses and bulge M/L ratios can be recovered (without the added computational expense of modeling haloes) by using separate bulge and disc components.
We measure the black hole mass in the nearby active galaxy Centaurus A (NGC 5128) using a new method based on spectroastrometry of a rotating gas disk. The spectroastrometric approach consists in measuring the photocenter position of emission lines for different velocity channels. In a previous paper we focused on the basic methodology and the advantages of the spectroastrometric approach with a detailed set of simulations demonstrating the possibilities for black hole mass measurements going below the conventional spatial resolution. In this paper we apply the spectroastrometric method to multiple longslit and integral field near infrared spectroscopic observations of Centaurus A. We find that the application of the spectroastrometric method provides results perfectly consistent with the more complex classical method based on rotation curves: the measured BH mass is nearly independent of the observational setup and spatial resolution and the spectroastrometric method allows the gas dynamics to be probed down to spatial scales of ~0.02, i.e. 1/10 of the spatial resolution and ~1/50 of BH sphere of influence radius. The best estimate for the BH mass based on kinematics of the ionized gas is then log(MBH (sin i)^2/Modot)=7.5 pm 0.1 which corresponds to MBH = 9.6(+2.5-1.8) times 10^7 Modot for an assumed disk inclination of i = 35deg. The complementarity of this method with the classic rotation curve method will allow us to put constraints on the disk inclination which cannot be otherwise derived from spectroastrometry. With the application to Centaurus A, we have shown that spectroastrometry opens up the possibility of probing spatial scales smaller than the spatial resolution, extending the measured MBH range to new domains which are currently not accessible: smaller BHs in the local universe and similar BHs in more distant galaxies.
We present a promising new technique, the g-distribution method, for measuring the inclination angle (i), the innermost stable circular orbit (ISCO), and the spin of a supermassive black hole. The g-distribution method uses measurements of the energy shifts in the relativistic iron line emitted by the accretion disk of a supermassive black hole due to microlensing by stars in a foreground galaxy relative to the g-distribution shifts predicted from microlensing caustic calculations. We apply the method to the gravitationally lensed quasars RX J1131-1231 (z_s=0.658, z_l=0.295), QJ 0158-4325 (z_s=1.294, z_l=0.317), and SDSS 1004+4112 (z_s=1.734, z_l=0.68). For RX J1131-1231 our initial results indicate that r_ISCO<8.5 gravitational radii (r_g) and i > 76 degrees. We detect two shifted Fe lines, in several observations, as predicted in our numerical simulations of caustic crossings. The current DeltaE-distribution of RX J1131-1231 is sparsely sampled but further X-ray monitoring of RX J1131-1231 and other lensed quasars will provide improved constraints on the inclination angles, ISCO radii and spins of the black holes of distant quasars.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
