相关论文: Circumnuclear Structures in Megamaser Host Galaxie…
We present new HST I-band images of a sample of 77 nearby, late-type spiral galaxies with low inclination. The main purpose of this catalog is to study the frequency and properties of nuclear star clusters. In 59 galaxies of our sample, we…
The masses of supermassive black holes (SMBHs, M_BH=10^6-10^11 Msun) in the centres of galaxies are related to the host stellar spheroid mass and velocity dispersion. A key question is how these relations originate, and over which range of…
Growing evidence indicate supermassive black holes (SMBHs) in the mass range of $M_{\rm BH}$$\sim 10^6-10^{10}M_{\odot}$ lurking in central bulges of many galaxies. Extensive observations reveal fairly tight power laws of $M_{\rm BH}$…
We present results from a study to determine whether relations, established in the local Universe, between the mass of supermassive black holes (SMBHs) and their host galaxies are in place at higher redshifts. We establish a…
Three sets of HST+COSTAR FOS and FOC observations provide strong evidence that the nuclear disk in M87 is in Keplerian rotation around a black hole with a mass of (2 - 3)x10^9 M_sol. A deep (6 orbits), high resolution H-alpha+[NII] PC2 HST…
We investigate the structural properties of nuclear star clusters in late-type spiral galaxies. More specifically, we fit analytical models to HST images of 39 nuclear clusters in order to determine their effective radii after correction…
Nuclear star clusters (NSCs) are dense, compact stellar systems only a few parsecs across, located at galaxy centers. Their small sizes make them difficult to resolve spatially. NSCs often coexist with massive black holes, and both trace…
Recent spectroscopic and VLBI-imaging observations of bright extragalactic water maser sources have revealed that the megamaser emission often originates in thin circumnuclear disks near the centers of active galactic nuclei (AGNs). Using…
Intermediate-mass black holes (IMBHs; $M_{BH} <2*10^{5} M_{\odot}$) in galaxy centers are cruciel for painting a coherent picture of the formation and growth of supermassive black holes (SMBHs). Using Big Data analysis, we identified 305…
Recent years have seen dramatic progress in the study of the core and nuclear properties of galaxies. The structure of the cores has been shown to vary methodically with global and nuclear properties, as cores respond to the mechanisms by…
(Abridged) The repeated discovery of supermassive black holes (SMBHs) at the centers of galactic bulges, and the discovery of relations between the SMBH mass (M) and the properties of these bulges, has been fundamental in directing our…
Using HST observations of 147 host galaxies of low-mass black holes (BHs), we systematically study the structures and scaling relations of these active galaxies. Our sample is selected to have central BHs with virial masses ~10^5-10^6 solar…
A fundamental role is attributed to supermassive black holes (SMBH), and the feedback they generate, in the evolution of galaxies. But theoretical models trying to reproduce the relation between the SMBH mass and stellar velocity dispersion…
As the closest example of a galactic nucleus, the Galactic center presents an exquisite laboratory for learning about supermassive black holes (SMBH) and their environs. Detailed studies of stellar dynamics deep in the potential well of a…
Observations of stellar kinematics, gas dynamics and masers around galactic nuclei have now firmly established that many galaxies host central supermassive black holes (SMBHs) with masses in the range $10^6 \sim 10^9$M$_{\odot}$. However,…
In large spheroidal stellar systems, such as elliptical galaxies, one invariably finds a 10^6-10^9 M_Sun supermassive black hole at their centre. In contrast, within dwarf elliptical galaxies one predominantly observes a 10^5-10^7 M_Sun…
We present new CRIRES spectroscopic observations of BrGamma in the nuclear region of the Circinus galaxy, obtained with the aim of measuring the black hole (BH) mass with the spectroastrometric technique. The Circinus galaxy is an ideal…
Understanding the co-evolution between supermassive black holes (SMBHs) and their host galaxies provides crucial insights into SMBH formation and galaxy assembly in these cosmic ecosystems. However, measuring this co-evolution, as traced by…
We use numerical simulations to examine the substructure within galactic and cluster mass halos that form within a hierarchical universe. Clusters are easily reproduced with a steep mass spectrum of thousands of substructure clumps that…
Observations of line emission from water masers near the center of the galaxy NGC 4258 have recently provided compelling evidence for rotating disk of gas, viewed nearly edge-on, surrounding a massive black hole (Miyoshi etal. 1995). We…