1. Introduction

2. Identification of Hα emitters, line flux measurements, and detection limits

2.1. Selection of Hα emitters candidates

2.2. Identification of Hα emitters

2.3. Hα line flux measurements

2.4. Detection limits in OTELO

3. Luminosity function at 𝑧∼0.40

3.1. Completeness correction

3.2. Volume sampled and cosmic variance

3.3. Hα luminosity function

3.4. Role of AGN hosts

4. Conclusions