The OTELO survey: Faint end of the luminosity function of [OII] emitters at <z>= 1.43

TL;DR

This study analyzes the faint end of the [OII] luminosity function at redshift 1.43 using the OTELO survey, revealing a steep slope and providing insights into star formation in low-mass galaxies.

Contribution

It presents the first detailed measurement of the faint-end slope of the [OII] luminosity function at z~1.43, including analysis of selection biases and cosmic variance effects.

Findings

Faint-end slope of the LF is $oldsymbol{ ext{-1.42}\pm0.06}$.

Sample predominantly consists of low-mass, late-type galaxies.

Cosmic variance significantly impacts LF normalization estimates.

Abstract

In this paper, we aim to study the main properties and luminosity function (LF) of the [OII] emitters detected in the OTELO survey in order to characterise the star formation processes in low-mass galaxies at $z\sim1.43$ and to constrain the faint-end of the LF. Here, we describe the selection method and analysis of the emitters obtained from narrow-band scanning techniques. In addition, we present several relevant properties of the emitters and discuss the selection biases and uncertainties in the determination of the LF and the star formation rate density (SFRD). We confirmed a total of 60 sources from a preliminary list of 332 candidates as [OII] emitters. Approximately 93% of the emitters have masses in the range of $10^{8}<M_{*}/{\rm M_{\odot}}<10^{9}$. All of our emitters are classified as late-type galaxies, with a lower value of $(u-v)$\, when compared with the rest of the emitters of the OTELO survey. We find that the cosmic variance strongly affects the normalisation ($\phi^*$) of the LF and explains the discrepancy of our results when compared with those obtained from surveys of much larger volumes. However, we are able to determine the faint-end slope of the LF, namely, $\alpha=-1.42\pm0.06$, by sampling the LF down to $\sim1$\,dex lower than in previous works. We present our calculation of the SFRD of our sample and compare it to the value obtained in previous studies from the literature.