The effect of the environment on the H I scaling relations

We use a volume-, magnitude-limited sample of nearby galaxies to investigate the effect of the environment on the H I scaling relations. We confirm that the H I-to-stellar mass ratio anticorrelates with stellar mass, stellar mass surface density and NUV - r colour across the whole range of parameters covered by our sample (109 less than or similar to M-* less than or similar to 10(11) M-circle dot, 7.5 less than or similar to mu(*) less than or similar to 9.5 M-circle dot kpc(-2), 2 less than or similar to NUV - r (less than or similar to) 6 mag). These scaling relations are also followed by galaxies in the Virgo cluster, although they are significantly offset towards lower gas content. Interestingly, the difference between field and cluster galaxies gradually decreases moving towards massive, bulge-dominated systems. By comparing our data with the predictions of chemo-spectrophotometric models of galaxy evolution, we show that starvation alone cannot explain the low gas content of Virgo spirals and that only ram-pressure stripping is able to reproduce our findings. Finally, motivated by previous studies, we investigate the use of a plane obtained from the relations between the H I-to-stellar mass ratio, stellar mass surface density and NUV - r colour as a proxy for the H I deficiency parameter. We show that the distance from the 'H I gas fraction plane' can be used as an alternative estimate for the H I deficiency, but only if carefully calibrated on pre-defined samples of 'unperturbed' systems.