Related papers: An H-alpha nuclear spiral structure in the E0 acti…
While the galactic density wave theory is over 50 years old and well known in science, whether it fits our own Milky Way disk has been difficult to say. Here we show a substructure inside the spiral arms. This substructure is reversing with…
The broad (FWHM ~ 10,000 km/s) double-peaked H{\alpha} profile from the LINER/Seyfert 1 nucleus of NGC 1097 was discovered in 1991, and monitored for the following 11 years. The profile showed variations attributed to the rotation of gas in…
New observations using narrow band imaging, long-slit spectroscopy and MERLIN observations of the nuclear region of the Seyfert galaxy NGC~4051 have been made. An edge brightened, triangular region of ionized gas extending 420 pc from the…
The present study of the two-stream instability in stellar disks with counter-rotating components of stars and/or gas is stimulated by recently discovered counter-rotating spiral and S0 galaxies. Strong linear two-stream instability of…
The protostar IRAS 15398-3359 is associated with a bipolar molecular outflow ejected in an nearly northeast-southwest (NE-SW) direction which has been extensively studied. It has been suggested previous episodic accretion events by this…
The Sc galaxy NGC 6181 was observed at the 6m telescope of SAO RAS with the scanning Perot-Fabry interferometer in the H-alpha emission line and at the 1m telescope of SAO RAS in BVRI broadband filters with CCD. Subtraction of the mean…
Observations at high spectral and temporal resolution are presented of the dwarf nova EX Dra in outburst. The disk seen in the He I line reconstructed by Doppler tomography shows a clear two-armed spiral pattern pointing to spiral shocks in…
We analyze formation of grand-design two-arm spiral structure in the nuclear regions of disk galaxies. Such morphology has been recently detected in a number of objects using high-resolution near-infrared observations. Motivated by the…
The results of $H_\alpha$ and [NII]$\lambda 6583$ observations of the spiral galaxy NGC 1084 at the SAO 6m telescope with a Fabry-Perot interferometer are presented. The complex structure of the emission line profile has revealed the…
The bulk of the molecular line emission in the double barred galaxy NGC4303 as observed in its CO(1-0) line with the OVRO mm-interferometer comes from two straight gas lanes which run north-south along the leading sides of the large-scale…
Integral field spectroscopy of the inner region of the Galactic Center, over a field of roughly 40"x40" was obtained at 2.06 microns (He I) and 2.16 microns (Brackett-gamma) using BEAR, an imaging Fourier Transform Spectrometer, at spectral…
We present Wide Field Spectrograph (WiFeS) integral field spectroscopy and HST FOS spectroscopy for the LINER galaxy NGC 1052. We infer the presence of a turbulent accretion flow forming a small-scale accretion disk. We find a large-scale…
Spitzer Space Telescope mid-infrared images of the radio galaxy Centaurus A reveal a shell-like, bipolar, structure 500 pc to the north and south of the nucleus. This shell is seen in 5.8, 8.0 and 24 micron broad-band images. Such a…
The intriguing nearly face-on southern ringed spiral galaxy NGC 4622, the first galaxy definitively shown to have leading spiral structure, is revisited in this paper with new images from the Hubble Space Telescope's WFPC2, together with…
The radio lobes of the radio galaxy Hercules A contain intriguing ring-like structures concentric with the jet axis. To investigate the occurrence of such features, we have used hydrodynamic simulations of jets with a range of Mach numbers…
Nuclear spirals naturally form as a gas response to non-axisymmetry in the galactic potential, even if the degree of this asymmetry is very small. Linear wave theory well describes weak nuclear spirals, but spirals induced by stronger…
High-mass protostars (M$_{\star} >$ 8 M$_{\odot}$) are thought to gain the majority of their mass via short, intense bursts of growth. This episodic accretion is thought to be facilitated by gravitationally unstable and subsequently…
Nuclear rings, prevalent in barred galaxies, are essential to understanding gas transport toward galactic nuclei. However, the peculiar nuclear ring in our neighboring galaxy M31 remains poorly understood. Here we present a comprehensive…
We present the results from 1.5 and 5 GHz phase-referenced VLBA and 1.5 GHz Karl G. Jansky Very Large Array (VLA) observations of the Seyfert 2 galaxy KISSR1219, which exhibits double peaked emission lines in its optical spectrum. The VLA…
Companions at sub-arcsecond separation from young stars are difficult to image. However their presence can be inferred from the perturbations they create in the dust and gas of protoplanetary disks. Here we present a new interpretation of…