14 research outputs found
2D Spectroscopy of Candidate Polar-Ring Galaxies: I. The Pair of Galaxies UGC 5600/09
Observations of the pair of galaxies VV 330 with the SCORPIO multimode
instrument on the 6-m Special Astrophysical Observatory telescope are
presented. Large-scale velocity fields of the ionized gas in H-alfa and
brightness distributions in continuum and H-alfa have been constructed for both
galaxies with the help of a scanning Fabry Perot interferometer. Long-slit
spectroscopy is used to study the stellar kinematics. Analysis of the data
obtained has revealed a complex structure in each of the pair components. Three
kinematic subsystems have been identified in UGC 5600: a stellar disk, an inner
gas ring turned with respect to the disk through ~80degrees, and an outer gas
disk. The stellar and outer gas disks are noncoplanar. Possible scenarios for
the formation of the observed multicomponent kinematic galactic structure are
considered, including the case where the large-scale velocity field of the gas
is represented by the kinematic model of a disk with a warp. The velocity field
in the second galaxy of the pair, UGC 5609, is more regular. A joint analysis
of the data on the photometric structure and the velocity field has shown that
this is probably a late-type spiral galaxy whose shape is distorted by the
gravitational interaction, possibly, with UGC 5600.Comment: 18 pages, 6 figure
NGC 7468: a galaxy with an inner polar disk
We present our spectroscopic observations of the galaxy NGC 7468 performed at
the 6-m Special Astrophysical Observatory telescope using the UAGS long-slit
spectrograph, the multipupil fiber spectrograph MPFS, and the scanning
Fabry-Perot interferometer (IFP). We found no significant deviations from the
circular rotation of the galactic disk in the velocity field in the regions of
brightness excess along the major axis of the galaxy (the putative polar ring).
Thus, these features are either tidal structures or weakly developed spiral
arms. However, we detected a gaseous disk at the center of the galaxy whose
rotation plane is almost perpendicular to the plane of the galactic disk. The
central collision of NGC 7468 with a gas-rich dwarf galaxy and their subsequent
merging seem to be responsible for the formation of this disk.Comment: 8 pages, 6 figures, accepted in Astronomy Letters, 2004, vol 30., N
9, p. 58
Inner Polar Rings and Disks: Observed Properties
A list of galaxies with inner regions revealing polar (or strongly inclined
to the main galactic plane) disks and rings is compiled from the literature
data. The list contains 47 galaxies of all morphological types, from E to Irr.
We consider the statistics of the parameters of polar structures known from
observations. The radii of the majority of them do not exceed 1.5 kpc. The
polar structures are equally common in barred and unbarred galaxies. At the
same time, if a galaxy has a bar (or a triaxial bulge), this leads to the polar
disk stabilization - its axis of rotation usually coincides with the major axis
of the bar. More than two thirds of all considered galaxies reveal one or
another sign of recent interaction or merging. This fact indicates a direct
relation between the external environment and the presence of an inner polar
structure.Comment: 12 pages, 3 figures, accepted to Astrophysical Bulletin. Minor
changes and corrections are still possibl
Study of the structure and kinematics of the NGC 7465/64/63 triplet galaxies
This paper is devoted to the analysis of new observational data for the group
of galaxies NGC 7465/64/63, which were obtained at the 6-m telescope of the
Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS)
with the multimode instrument SCORPIO and the Multi Pupil Fiber Spectrograph.
For one of group members (NGC 7465) the presence of a polar ring was suspected.
Large-scale brightness distributions, velocity and velocity dispersion fields
of the ionized gas for all three galaxies as well as line-of-sight velocity
curves on the basis of emission and absorption lines and a stellar velocity
field in the central region for NGC 7465 were constructed. As a result of the
analysis of the obtained information, we revealed an inner stellar disk (r ~
0.5 kpc) and a warped gaseous disk in addition to the main stellar disk, in NGC
7465. On the basis of the joint study of photometric and spectral data it was
ascertained that NGC 7464 is the irregular galaxy of the IrrI type, whose
structural and kinematic peculiarities resulted most likely from the
gravitational interaction with NGC 7465. The velocity field of the ionized gas
of NGC 7463 turned out typical for spiral galaxies with a bar, and the bending
of outer parts of its disk could arise owing to the close encounter with one of
galaxies of the environment.Comment: 20 pages, 6 figure
The phenomenon of the galaxy NGC 6286: a forming polar ring or a superwind?
(abridged)We present the observations of the pair of interacting galaxies
NGC6285/86 carried out with the 6m SAO RAS telescope by using 1D and 2D
spectroscopy. The observations of NGC6286 with a long-slit spectrograph (UAGS)
near the H-alpha line revealed the rotation of the gaseous disk around an axis
offset by 5''-7'' from the photometric center and a luminous gas at a distance
up to 9 kpc in a direction perpendicular to the galactic plane. Using a
multipupil fiber spectrograph (MPFS), we constructed the velocity fields of the
stellar and gaseous components in the central region of this galaxy, which
proved to be similar. The similar line-of-sight velocities of the pair and the
wide (5'x 5') field of view of the scanning Fabry-Perot interferometer (IFP)
allowed us to obtain images in the H-alpha and [NII]6583 emission lines and in
the continuum as well as to construct the line-of-sight velocity fields and to
map the distribution of the [NII]6583/H-alpha ratio for both galaxies
simultaneously. Based on these data, we studied the gas kinematics in the
galaxies, constructed their rotation curves, and estimated their masses. We
found no evidence of gas rotation around the major axis of NGC6286, which
argues against the assumption that this galaxy has a forming polar ring. The
IFP observations revealed an emission nebula around this galaxy with a
structure characteristic for superwind galaxies. The large [NII]6583/H-alpha
ratio, which suggests the collisional excitation of its emission, and the high
infrared luminosity are additional arguments for the hypothesis of a superwind
in the galaxy NGC 6286. A close encounter of the two galaxies was probably
responsible for the starburst and the bipolar outflow of hot gas from the
central region of the disk.Comment: 10 pages, 6 figures, accepted in Astronomy Letters, 2004, vol 30., N
Тесты на константные неисправности как веб-сервис
In this paper, we tell about a web-service we would like to develop. There are two goals we aim at, when developing this service. The first one is to give researchers a platform, where they could conduct preliminary experiments with different methods of test generation for digital circuits, in order to check different ideas. The second one is an opportunity to share implementations of new developed methods “on-the-fly”. The web-service development procedure was splitted into three stages: the architecture design, a light version implementation and the actual implementation. This paper tells about first two stages. There are two types of web-service architectures – with monolithic kernel and with microkernel – and our architecture has the properties of both types. The intention was to have monolithic kernel, since the desired functionality is not that hard to implement. However, the property of being extensible by implementations of new methods implies that part of the functions (namely the methods implementations) should be designed as separate sub-services. The light version implementation was done for the only method: method of fault domain enumeration for the stuck-at-faults fault model. It proved that the designed architecture is viable. However, some issues with the architecture were discovered. A mechanism of on-the-fly deployment of a new method is unclear, since it is not obvious, how to satisfy possible dependences of the implementation. Also, the architecture does not follow the classical web-service design: the service has states, that should not be, if a service is intended to be the classical one. The resolution of these issues is left for the future