The Low Mass End of the Fundamental Relation for Gravitationally Lensed Star Forming Galaxies at 1<z<6

TL;DR

This study investigates the fundamental relation between stellar mass, star formation rate, and metallicity in low-mass, high-redshift galaxies using gravitational lensing to extend the relation to lower masses and metallicities.

Contribution

It provides a new modified fit to the fundamental relation specifically for low-mass, low-metallicity galaxies at high redshift, highlighting differences from low-redshift galaxy relations.

Findings

Low-mass galaxies show large scatter in the fundamental relation.

A weaker dependence of metallicity on star formation rate and stellar mass is observed.

The relation differs from that of high-mass, high-metallicity SDSS galaxies.

Abstract

We present VLT/X-shooter spectra of 13 galaxies in the redshift range 1< z < 6, which are strongly lensed by massive galaxy clusters. Spectroscopic redshifts are measured for nine galaxies, while three sources have redshifts determined from continuum breaks in their spectra. The stellar masses of the galaxies span four orders of magnitude between 10^7 and 10^11 M_sun and have luminosities at 1500 A rest-frame between 0.004 and 9 L^* after correcting for the magnification. This allows us to probe a variety of galaxy types from young, low-mass starburst galaxies to massive evolved galaxies. The lensed galaxies with stellar masses less than 10^10 M_sun have a large scatter compared to the fundamental relation between stellar mass, star formation rates and oxygen abundances. We provide a modified fit to the fundamental relation for low-mass, low-metallicity galaxies with a weaker dependence of the metallicity on either the star formation rate or stellar mass compared to low-redshift, high-mass and high-metallicity SDSS galaxies.