On the Star Formation Rate, Initial Mass Function, and Hubble Type of Disk Galaxies and the Age of the Universe

1996 ◽  
Vol 457 ◽  
pp. 118 ◽  
Author(s):  
Jesper Sommer-Larsen
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Disk Galaxies ◽  
Age Of The Universe ◽  
The Universe

scholarly journals A New Theory of Star Formation: Analytical Mass Function and Star Formation Rate

1987 ◽  
Vol 115 ◽  
pp. 442-443
Author(s):  
A. Di Fazio
Keyword(s):  
Mass Spectrum ◽  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Mass Function ◽  
Initial Mass Function ◽  
Time Dependent ◽  
Initial Mass ◽  
Fragmentation Rate

An analytical, theoretical, time-dependent initial mass function is derived for the objects created in the fragmentation of a gravitationally unstable gas protocloud. The mass spectrum depends on the chemical-dynamical-radiative evolution of the protocloud and it peaks at a mass slightly greater than the minimum Jeans mass attained throughout the evolution. A fragmentation rate mass spectrum is also analytically derived.

scholarly journals The influence of star clusters on galactic disks: new insights in star-formation in galaxies

2008 ◽  
Vol 4 (S254) ◽  
pp. 209-220
Author(s):  
Pavel Kroupa
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Stellar Population ◽  
Dwarf Galaxy ◽  
Star Clusters ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Disk Galaxies ◽  
Galactic Disks

AbstractStars form in embedded star clusters which play a key role in determining the properties of a galaxy's stellar population. A large fraction of newly born massive stars are shot out from dynamically unstable embedded-cluster cores spreading them to large distances before they explode. Embedded clusters blow out their gas once the feedback energy from the new stellar population overcomes its binding energy, leading to cluster expansion and in many cases dissolution into the galaxy. Galactic disks may be thickened by such processes, and some thick disks may be the result of an early epoch of vigorous star-formation. Binary stellar systems are disrupted in clusters leading to a lower fraction of binaries in the field, while long-lived clusters harden degenerate-stellar binaries such that the SNIa rate may increase by orders of magnitude in those galaxies that were able to form long-lived clusters. The stellar initial mass function of the whole galaxy must be computed by adding the IMFs in the individual clusters. The resulting integrated galactic initial mass function (IGIMF) is top-light for SFRs < 10 M⊙/yr, and its slope and, more importantly, its upper stellar mass limit depend on the star-formation rate (SFR), explaining naturally the mass–metallicity relation of galaxies. Based on the IGIMF theory, the re-calibrated Hα-luminosity–SFR relation implies dwarf irregular galaxies to have the same gas-depletion time-scale as major disk galaxies, implying a major change of our concept of dwarf-galaxy evolution. A galaxy transforms about 0.3 per cent of its neutral gas mass every 10 Myr into stars. The IGIMF-theory also naturally leads to the observed radial Hα cutoff in disk galaxies without a radial star-formation cutoff. It emerges that the thorough understanding of the physics and distribution of star clusters may be leading to a major paradigm shift in our understanding of galaxy evolution.

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