Star-formation in isolated galaxies


Specific star formation rate and stellar mass in isolated galaxies of different morphological types.
Fig. 8. (log_ssfr) Specific star formation rate and stellar mass in isolated galaxies of different morphological types. The horizontal line corresponds to the limit logSSFR = −9.4 [yr−1] (fig. 4 from Karachentsev et al., 2013).
Specific star formation rate and stellar mass in MRK galaxies of different morphological types
Fig. 9. (mrk_ssfr) Specific star formation rate and stellar mass in MRK galaxies of different morphological types: open circles correspond to T=9,10; crosses correspond to T=2÷8; black circles are T

In our paper Karachentsev et al. (2013) we use the FUV fluxes measured with the GALEX to study the star formation properties of galaxies collected in the Catalog of nearby isolated galaxies in the volume z < 0.01; LOG.  Only 5% of LOG galaxies are classified as early types: E, S0, S0/a, however, they systematically differ from normal E and S0 galaxies by lower luminosity and presence of gas and dust. We find that almost all galaxies in our sample have their SSFR below 0.4 [Gyr−1 ]. This limit is also true even for a sample of active star-burst Markarian galaxies situated in the same volume (one can compare fig. 8 and fig.9). The existence of such a quasi-Eddington limit for galaxies seems to be a key factor which characterizes the

transformation of gas into stars at the current epoch.