Star Formation in Disks
نویسندگان
چکیده
منابع مشابه
Star Formation Thresholds in Galactic Disks
We report the first results of a detailed study of the star formation law in a sample of 32 nearby spiral galaxies with well-measured rotation curves, HI and H2 (as traced by CO) surface density profiles, and new Hα CCD photometry. In this paper we present an atlas of Hα images and radial surface brightness profiles and describe a surface-density threshold in the star formation law. Prominent b...
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We investigate the effects of a variety of ingredients that must enter into a realistic model for disk-galaxy formation, focusing primarily on the Tully-Fisher (TF) relation and its scatter in several wavebands. In particular, we employ analytic distributions for halo-formation redshifts and halo spins, empirical star-formation rates and initial mass functions, realistic stellar populations, an...
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Star formation is enhanced in spiral arms because of a combination of orbit crowding, cloud collisions, and gravitational instabilities. The characteristic mass for the instability is 10 M⊙ in gas and 10 5 M⊙ in stars, and the morphology is the familiar beads on a string with 1-2 kpc separation. Similar instabilities occur in resonance rings and tidal tails. Sequential triggering from stellar p...
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With the help of the multiphase chemical evolution model (Mollá, Hardy & Beauchamps 1999) we have derived the evolutionary histories of the galaxies NGC 4303, NGC 4321 y NGC 4535. With these histories and an evolutionary synthesis model, we were able to reproduce their observed radial distributions of the spectral indices Mg2 and Fe5270. Chemical evolution models however may fit well the presen...
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We discuss the stability of galactic disks in which the energy of interstellar clouds is gained in encounters with expanding supernova remnants and lost in inelastic collisions. Energy gain and loss processes introduce a phase difference between the pressure and density perturbations, making disks unstable on small scales for several recipes of star formation. This is in contrast to the standar...
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ژورنال
عنوان ژورنال: Highlights of Astronomy
سال: 1983
ISSN: 1539-2996
DOI: 10.1017/s1539299600005128