The Lockman-SpReSO project

Main properties of infrared-selected star-forming galaxies

¹ Instituto de Astrofísica de Canarias, 38205 La Laguna, Tenerife, Spain
e-mail: mauro.gonzalez-ext@iac.es, mauromarago@gmail.com
² Departamento de Astrofísica, Universidad de La Laguna (ULL), 38205 La Laguna, Tenerife, Spain
³ Asociación Astrofísica para la Promoción de la Investigación, Instrumentación y su Desarrollo, ASPID, 38205 La Laguna, Tenerife, Spain
⁴ Fundación Galileo Galilei-INAF Rambla José Ana Fernández Pérez, 7, 38712 Breña Baja, Tenerife, Spain
⁵ Departamento de Física de la Tierra y Astrofísica, Instituto de Física de Partículas y del Cosmos, IPARCOS. Universidad Complutense de Madrid (UCM), 28040 Madrid, Spain
⁶ Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 70-264, 04510 Ciudad de México, Mexico
⁷ Institut de Radioastronomie Millimétrique (IRAM), Av. Divina Pastora 7, Núcleo Central, 18012 Granada, Spain
⁸ Centro de Astrobiología (CSIC/INTA), 28692 ESAC Campus, Villanueva de la Cañada, Madrid, Spain
⁹ Astronomical Observatory Institute, Faculty of Physics, Adam Mickiewicz University, ul. Słoneczna 36, 60-286 Poznań, Poland
¹⁰ Instituto de Física de Cantabria (CSIC-Universidad de Cantabria), 39005 Santander, Spain
¹¹ ISDEFE for European Space Astronomy Centre (ESAC)/ESA, PO Box 78, 28690 Villanueva de la Cañada, Madrid, Spain

Received: 15 January 2024
Accepted: 11 April 2024

Abstract

Aims. In this work, we carry out a comprehensive study using galaxy data from the Lockman Spectroscopic Redshift Survey using Osiris (Lockman-SpReSO) project, a far-infrared (FIR) selected sample of galaxies observed using optical spectroscopy. We analyse a sub-sample of star-forming galaxies (SFGs) with secure spectroscopic redshifts, mostly in the luminous infrared (IR) galaxy domain. From these galaxies, parameters such as the extinction, star formation rate (SFR), and metallicity have been derived. The present paper examines how these properties evolve in relation to each other and in comparison with low-redshift FIR and non-FIR-selected samples of galaxies.

Methods. We applied distinct selection criteria to attain an SFG sample with minimal AGN contamination. Multiple approaches were used to estimate the intrinsic extinction, SFR, and gas-phase metallicity for the SFGs. In conjunction with findings in the literature, we examined the correlation between SFRs and stellar masses (M_*), as well as the metallicity evolution depending on M_*. Finally, we also studied the 3D relationship between M_*, SFR, and metallicity.

Results. From the initial spectroscopic sample of 409 FIR-selected objects from the Lockman-SpReSO catalogue, 69 active galactic nuclei (AGNs) were identified and excluded (17%), which is nearly double the percentage found in local studies, leaving us with a sample of 340 SFGs. The analysis of the M_*–SFR relationship revealed that Lockman-SpReSO IR-selected SFGs show signs of evolution at redshifts z > 0.4, shifting above the main sequence (MS), with a mean value of ∼0.4 dex. They are located within the starburst galaxy region since 78% of the galaxies fall into this category. In addition, no evident flattening was found in the relation to specific SFR with redshift for log M_* (M_⊙)≳10.5. In line with the M_*–metallicity relation (MZR) outcomes published in previous studies for optically selected SFGs; however, during the analysis of the MZR, it was found that IR-selected SFGs exhibit lower metallicities than the values anticipated on the basis of their M_* and redshift. During the investigation of the 3D M_*–SFR–metallicity relation (FP), it was established that the research sample is consistent with relations published in the existing literature, with an average scatter of ∼0.2 dex. However, a re-calibration of the FP when using the SFR obtained from the IR luminosity is required and, in this case, no attenuation in the correlation for log M_* (M_⊙)≳10.5 was observed. This result points to a possible evolution of the more massive fraction of the sample in the sense that the present-day star formation rate is lower with respect to the average rate of star formation in the past.