ﻻ يوجد ملخص باللغة العربية
Though S0 galaxies are usually thought to be `red and dead, they demonstrate often star formation organized in ring structures. We try to clarify the nature of this phenomenon and its difference from star formation in spiral galaxies. The moderate-luminosity nearby S0 galaxy, NGC 4513, is studied here. By applying long-slit spectroscopy along the major axis of NGC 4513, we have measured gas and star kinematics, Lick indices for the main body of the galaxy, and strong emission-line flux ratios in the ring. After inspecting the gas excitation in the ring using the line ratios diagnostic diagrams and have assured that it is ionized by young stars, we have determined the gas oxygen abundance by using popular strong-line calibration methods. We have estimated star formation rate (SFR) in the outer ring by using the archival Galaxy Evolution Explorer (GALEX) ultraviolet images of the galaxy. The ionized gas counterrotates the stars over the whole extension of NGC 4513 so being accreted from outside. The gas metallicity in the ring is slightly subsolar, [O/H]=-0.2 dex, matching the metallicity of the stellar component of the main galactic disc. However the stellar component of the ring is much more massive than can be explained by the current star formation level in the ring. We conclude that probably the ring of NGC 4513 is a result of tidal disruption of a massive gas-rich satellite, or it may be a consequence of a long star-formation event provoked by a gas accretion from a cosmological filament having started some 3 Gyr ago.
Though S0 galaxies are usually thought to be `red and dead, they often demonstrate star formation organized in ring structures. We try to clarify the nature of this phenomenon and its difference from star formation in spiral galaxies. Two early-type
Though S0 galaxies are usually thought to be `red and dead, they demonstrate often star formation organized in ring structures. We try to clarify the nature of this phenomenon and its difference from star formation in spiral galaxies. The luminous S0
Strongly noncircular outer stellar disks have been found in two unbarred SA0 galaxies by analyzing spectroscopic data on the rotation of stars and photometric data on the shape and orientation of the isophotes. In NGC 502, the oval distortion of the
Very little work has been done on star formation in dwarf lenticular galaxies (S0s). We present 2D-spectroscopic and millimetre observations made by Centro Astronomico Hispano Aleman (CAHA) 3.5 m optical and the IRAM-30 m millimetre telescopes, respe
We present our results of the spectroscopic study of the lenticular galaxy NGC 4143 - an outskirt member of the Ursa Major cluster. Using the observations at the 6-m SAO RAS telescope with the SCORPIO-2 spectrograph and also the archive data of panor