166 research outputs found
The Largest Russian Optical Telescope BTA: Current Status and Modernization Prospects
The Russian 6-m telescope (BTA), once the largest telescope in the world and
now the largest optical telescope in Russia, has been successfully operating
for almost 45 years. In this paper we briefly overview the observing methods
the facility can currently provide, the ongoing projects on the development of
scientific equipment, the status of the telescope among the world's and Russian
astronomical communities, our ambitions to attract new users, and the prospects
the observatory wishes to realize in the near future.Comment: To be published in: I.I. Romanyuk, I.A. Yakunin, A.F. Valeev, and
D.O. Kudryavtsev (eds), Ground-Based Astronomy in Russia. 21st Century,
Proceedings of the All-Russian Conference, ISBN: 978-5-6045062-0-
NGC 7331: the Galaxy with the Multicomponent Central Region
We present the results of the spectral investigation of the regular Sb galaxy
NGC 7331 with the Multi-Pupil Field Spectrograph of the 6m telescope. The
absorption-line indices H-beta, Mgb, and are mapped to analyse the
properties of the stellar populations in the circumnuclear region of the
galaxy. The central part of the disk inside ~3" (200 pc) -- or a separate
circumnuclear stellar-gaseous disk as it is distinguished by decoupled fast
rotation of the ionized gas -- is very metal-rich, rather young, ~ 2 billion
years old, and its solar magnesium-to-iron ratio evidences for a very long
duration of the last episode of star formation there. However the gas
excitation mechanism now in this disk is shock-like. The star-like nucleus had
probably experienced a secondary star formation burst too: its age is 5 billion
years, much younger than the age of the circumnuclear bulge. But [Mg/Fe]=+0.3
and only solar global metallicity imply that the nuclear star formation burst
has been much shorter than that in the circumnuclear disk. The surrounding
bulge is rather old, 9--14 billion years old, and moderately metal-poor. The
rotation of the stars and gas within the circumnuclear disk is axisymmetric
though its rotation plane may be slightly inclined to the global plane of the
galaxy. Outside the circumnuclear disk the gas may experience non-circular
motions, and we argue that the low-contrast extended bulge of NGC 7331 is
triaxial.Comment: LATEX, 27 pages, + 15 Postscript figures. Accepted to Astronomical
Journal, July issu
- …