The OTELO Survey: The Star Formation Rate Evolution of Low-mass Galaxies

Cedrés, Bernabé, Pérez-García, Ana María, Pérez-Martínez, Ricardo, Cerviño, Miguel, Gallego, Jesús, Bongiovanni, Ángel, Cepa, Jordi, Navarro Martínez, Rocío, Nadolny, Jakub, Lara-López, Maritza A., Sánchez-Portal, Miguel, Alfaro, Emilio J., de Diego, José A., González-Otero, Mauro, Jesús González, J., Ignacio González-Serrano, J., Padilla Torres, Carmen P. The OTELO Survey: The Star Formation Rate Evolution of Low-mass Galaxies, The Astrophysical Journal Letters 915(1): L17 (2021) DOI: 10.3847/2041-8213/ac0a7e

We present the analysis of a sample of Hα, Hβ, and [O II] emission line galaxies from the OTELO survey, with masses typically below log(M∗/M⊙)∼9.4 and redshifts between z ~ 0.4 and 1.43. We study the star formation rate, star formation rate density, and their number density and evolution with redshift. We obtain a robust estimate of the specific star formation rate-stellar mass relation based on the lowest-mass sample published so far. We also determine a flat trend of the star formation rate density (SFRD) and number density with redshift. Our results suggest a scenario of no evolution of the number density of galaxies, regardless of their masses, up to redshift z ~ 1.4. This implies a gradual change of the relative importance of the star-forming processes, from high-mass galaxies to low-mass galaxies, with decreasing redshift. We also find little or no variation of the SFRD in the redshift range of 0.4 < z < 1.43.

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