2025/06/10 by Jaimie R. Sheil, M. J. I. Brown, Sheil, Jaimie R. +7
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics of Galaxies (astro-ph.GA) #Electrical and Electromagnetic Research #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.48550/arxiv.2506.08474
openalex publication_date 2025/06/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We have examined the nuclear spectra of very massive star-forming galaxies at z ∼ 0 to understand how they differ from other galaxies with comparable masses, which are typically passive. We selected a sample of 126 nearby massive star-forming galaxies (<100~\rm Mpc, 1011.3~\rmM_\odot ≤ M\rm stellar ≤ 1011.7~\rmM_\odot, 1 ~\rm M_\odot~yr-1< \rm SFR <13 ~\rm M_\odot~yr-1) from the 2MRS-Bright WXSC catalogue. LEDA morphologies indicate at least 63% of our galaxies are spirals, while visual inspection of Dark Energy Survey images reveals 75% of our galaxies to be spirals with the remainder being lenticular. Of our sample 59 have archival nuclear spectra, which we have modelled and subsequently measured emission lines ([NII]\rmλ6583, Hα\rmλ6563, [OIII]\rmλ5008, and Hβ\rmλ4863), classifying galaxies as star-forming, LINERS, or AGNs. Using a BPT diagram we find 83 ± 6 % of our galaxies, with sufficient signal-to-noise to measure all 4 emission lines, to be LINERs. Using the [NII]\rmλ6583/Hα\rmλ6563 emission line ratio alone we find that 79 ± 6 % of the galaxies (46 galaxies) with archival spectra are LINERs, whereas just ∼ 30% of the overall massive galaxy population are LINERs (Belfiore et al. 2016). Our sample can be considered a local analogue of the Ogle et al. (2016, 2019) sample of z ∼ 0.22 massive star-forming galaxies in terms of selection criteria, and we find 64% of their galaxies are LINERs using SDSS spectra. The high frequency of LINER emission in these massive star-forming galaxies indicates that LINER emission in massive galaxies may be linked to the presence of gas that fuels star formation.