Luminosity function of luminous compact star-forming galaxies

TL;DR

This study analyzes the luminosity functions of luminous compact star-forming galaxies, revealing that traditional Schechter functions do not fit well due to excess luminous galaxies, which are better modeled by Saunders and log-normal functions.

Contribution

It introduces alternative functions to model luminosity functions of star-forming galaxies, highlighting the limitations of the Schechter function for luminous populations.

Findings

Schechter function poorly fits luminous galaxy data

Saunders and log-normal functions provide better fits

Luminous galaxies have high star formation rates and luminosities

Abstract

We study H-alpha, far- and near-ultraviolet luminosity functions (LF) of the sample of 795 luminous compact star-forming galaxies with z<0.65. The parameters of optimal functions for LFs are obtained using the maximum likelihood method and the accuracy of fitting is estimated with the chi-squared method. We find that these LFs cannot be reproduced by the Schechter function because of an excess of very luminous galaxies. On the other hand, the Saunders function, the log-normal distribution and some new related functions are good approximations of LFs. The fact that LFs are not reproduced by the Schechter function can be explained by the propagating star formation. This may result in an excess of luminous starbursts with the mass of a young stellar population above 2*10^8 M_Sun as compared to the LF of the quiescent galaxies. The most luminous compact galaxies are characterised by H-alpha luminosities of > 5*10^{42} erg/s and star formation rates of > 40 M_Sun/yr.