The Formation of Extremely Diffuse Galaxy Cores by Merging Supermassive Black Holes
Permalink
Citation
Rantala , A , Johansson , P H , Naab , T , Thomas , J & Frigo , M 2018 , ' The Formation of Extremely Diffuse Galaxy Cores by Merging Supermassive Black Holes ' , Astrophysical Journal , vol. 864 , no. 2 , 113 . https://doi.org/10.3847/1538-4357/aada47
| Title: | The Formation of Extremely Diffuse Galaxy Cores by Merging Supermassive Black Holes |
| Author: | Rantala, Antti; Johansson, Peter H.; Naab, Thorsten; Thomas, Jens; Frigo, Matteo |
| Contributor organization: | Department of Physics |
| Date: | 2018-09-10 |
| Language: | eng |
| Number of pages: | 20 |
| Belongs to series: | Astrophysical Journal |
| ISSN: | 0004-637X |
| DOI: | https://doi.org/10.3847/1538-4357/aada47 |
| URI: | http://hdl.handle.net/10138/243768 |
| Abstract: | Given its velocity dispersion, the early-type galaxy NGC 1600 has an unusually massive (M-center dot = 1.7 x 10(10) M-circle dot) central supermassive black hole (SMBH) surrounded by a large core (r(b) = 0.7 kpc) with a tangentially biased stellar distribution. We present high-resolution equal-mass merger simulations including SMBHs to study the formation of such systems. The structural parameters of the progenitor ellipticals were chosen to produce merger remnants resembling NGC 1600. We test initial stellar density slopes of rho proportional to r(-1) and rho proportional to r(-3/2) and vary the initial SMBH masses from 8.5 x 10(8) to 8.5 x(.) 10(9) M-circle dot. With increasing SMBH mass, the merger remnants show a systematic decrease in central surface brightness, an increasing core size, and an increasingly tangentially biased central velocity anisotropy. Two-dimensional kinematic maps reveal decoupled, rotating core regions for the most massive SMBHs. The stellar cores form rapidly as the SMBHs become bound, while the velocity anisotropy develops more slowly after the SMBH binaries become hard. The simulated merger remnants follow distinct relations between the core radius and the sphere of influence, and the SMBH mass, similar to observed systems. We find a systematic change in the relations as a function of the progenitor density slope and present a simple scouring model reproducing this behavior. Finally, we find the best agreement with NGC 1600 using SMBH masses totaling the observed value of M-center dot = 1.7 x 10(10) M-circle dot. In general, density slopes of rho proportional to r(-3/2) for the progenitor galaxies are strongly favored for the equal-mass merger scenario. |
| Subject: |
galaxies: individual (NGC 1600)
galaxies: kinematics and dynamics methods: numerical DARK-MATTER FRACTIONS ELLIPTIC GALAXIES SPHERICAL GALAXIES GALACTIC NUCLEI ILLUSTRIS SIMULATION VELOCITY DISPERSION ATLAS(3D) PROJECT MINOR MERGERS ALGORITHMIC REGULARIZATION DYNAMICAL EVOLUTION 115 Astronomy, Space science |
| Peer reviewed: | Yes |
| Rights: | cc_by |
| Usage restriction: | openAccess |
| Self-archived version: | publishedVersion |
Files in this item
Total number of downloads: Loading...
| Files | Size | Format | View |
|---|---|---|---|
| Rantala_2018_ApJ_864_113.pdf | 2.169Mb |
View/ |
This item appears in the following Collection(s)
-
Articles from TUHAT CRIS [46490]
Related items
Showing items related by title, author, creator and subject.
-
(2016)We use the low-redshift Zurich Environmental Study (ZENS) catalog to study the dependence of the quenched satellite fraction at 10(10.0) M-circle dot -> 10(11.5) M-circle dot, and of the morphological mix of these quenched satellites, on three different environmental parameters: group halo mass, halo-centric distance, and large-scale structure (LSS) overdensity. Within the two mass bins into which we divide our galaxy sample, the fraction of quenched satellites is more or less independent of halo mass and the surrounding. LSS overdensity, but it increases toward the centers of the halos, as found in previous studies. The morphological mix of these quenched satellites is, however, constant with radial position in the halo, indicating that the well-known morphology-density relation results from the increasing fraction of quenched galaxies toward the centers of halos. If the radial variation in the quenched fraction reflects the action of two quenching processes, one related to mass and the other to environment, then the constancy with radius of the morphological outcome suggests that both have the same effect on the morphologies of the galaxies. Alternatively, mass and environment quenching may be two reflections of a single physical mechanism. The quenched satellites have larger bulge-to-total ratios (B/T) and smaller half-light radii than the star-forming satellites. The bulges in quenched satellites have very similar luminosities and surface brightness profiles, and any mass growth of the bulges associated with quenching cannot greatly change these quantities. The differences in the light-defined B/T and in the galaxy half-light radii are mostly due to differences in the disks, which have lower luminosities in the quenched galaxies. The difference in galaxy half-light radii between quenched and star-forming satellites is however larger than can be explained by uniformly fading the disks following quenching, and the quenched disks have smaller scale lengths than in star-forming satellites. This can be explained either by a differential fading of the disks with galaxy radius or the disks being generally smaller in the past, both of which would be expected in an inside-out disk growth scenario. The overall conclusion is that, at least at low redshifts, the structure of massive quenched satellites at these masses is produced by processes that operate before the quenching takes place. A comparison of our results with semianalytic models argues for a reduction in the efficiency of group halos in quenching their disk satellites and for mechanisms to increase the B/T of low-mass quenched satellites.
-
(2018)We present a 3 degrees x 3 degrees, 105-pointing, high-resolution neutral hydrogen (H I) mosaic of the M81 galaxy triplet, (including the main galaxies M81, M82, and NGC 3077, as well as dwarf galaxy NGC 2976) obtained with the Very Large Array C and D arrays. This H I synthesis mosaic uniformly covers the entire area and velocity range of the triplet. The observations have a resolution of similar to 20 '' or similar to 420 pc. The data reveal many small-scale anomalous velocity features highlighting the complexity of the interacting M81 triplet. We compare our data with Green Bank Telescope observations of the same area. This comparison provides evidence for the presence of a substantial reservoir of low-column density gas in the northern part of the triplet, probably associated with M82. Such a reservoir is not found in the southern part. We report a number of newly discovered kpc-sized low-mass H I clouds with H I masses of a few times 10(6) M-circle dot. A detailed analysis of their velocity widths show that their dynamical masses are much larger than their baryonic masses, which could indicate the presence of dark matter if the clouds are rotationally supported. However, due to their spatial and kinematical association with H I tidal features, it is more likely that the velocity widths indicate tidal effects or streaming motions. We do not find any clouds that are not associated with tidal features down to an H I mass limit of a few times 10(4) M-circle dot. We compare the H I column densities with resolved stellar density maps and find a star formation threshold around 3-6 x 10(20) cm(-2). We investigate the widths of the H I velocity profiles in the triplet and find that extreme velocity dispersions can be explained by a superposition of multiple components along the line of sight near M81 as well as winds or outflows around M82. The velocity dispersions found are high enough that these processes could explain the linewidths of damped-Ly alpha absorbers observed at high redshift.
-
(2019)We present the results of a search for galaxy clusters and groups in the ∼2 deg2 of the COSMOS field using all available X-ray observations from the XMM-Newton and Chandra observatories.We reach an X-ray flux limit of 3 × 10−16 erg cm−2 s−1 in the 0.5-2 keV range, and identify 247 X-ray groups with M200c = 8 × 1012-3 × 1014M at a redshift range of 0.08 ≤ z < 1.53, using the multiband photometric redshift and the master spectroscopic redshift catalogues of the COSMOS. The X-ray centres of groups are determined using high-resolution Chandra imaging. We investigate the relations between the offset of the brightest group galaxies (BGGs) from halo X-ray centre and group properties and compare with predictions from semi-analytic models and hydrodynamical simulations. We find that BGG offset decreases with both increasing halo mass and decreasing redshift with no strong dependence on the X-ray flux and SNR. We show that the BGG offset decreases as a function of increasing magnitude gap with no considerable redshift-dependent trend. The stellar mass of BGGs in observations extends over a wider dynamic range compared to model predictions. At z < 0.5, the central dominant BGGs become more massive than those with large offsets by up to 0.3 dex, in agreement with model prediction. The observed and predicted log-normal scatter in the stellar mass of both low- and large-offset BGGs at fixed halo mass is ∼0.3 dex.