Full spectrum fitting with photometry in PPXF: stellar population versus dynamical masses, non-parametric star formation history and metallicity for 3200 LEGA-C galaxies at redshift z ≈ 0.8

Journal article

I introduce some improvements to the PPXF method, which measures the stellar and gas kinematics, star formation history (SFH) and chemical composition of galaxies. I describe the new optimization algorithm that PPXF uses and the changes I made to fit both spectra and photometry simultaneously. I apply the updated PPXF method to a sample of 3200 galaxies at redshift 0.6 < z < 1 (median z = 0.76, stellar mass M∗ 3 × 1010 M), using spectroscopy from the LEGA-C survey (DR3) and 28-bands photometry from two different sources. I compare the masses from new JAM dynamical models with the PPXF stellar population M∗ and show the latter are more reliable than previous estimates. I use three differentstellar population synthesis(SPS) modelsin PPXF and both photometric sources. I confirm the main trend of the galaxies’ global ages and metallicity [M/H] with stellar velocity dispersion σ∗ (or central density), but I also find that [M/H] depends on age at fixed σ∗. The SFHsreveal a sharp transition from star formation to quenching for galaxies with lg(σ∗/km s−1) 2.3 (σ∗ 200 km s−1), or average mass density within 1 kpc lg(JAM 1 /Mkpc−2) 9.9 (JAM 1 7.9 × 109 M kpc−2), or with [M/H] −0.1, or with Sersic index lg nSer 0.5 (nSer 3.2). However, the transition is smoother as a function of M∗. These results are consistent for two SPS models and both photometric sources, but they differ significantly from the third SPS model, which demonstrates the importance of comparing model assumptions.

Authors: Cappellari, M

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Journal: Monthly Notices of the Royal Astronomical Society
• Volume: 526
• Issue: 3
• Pages: 3273-3300
• Publication date: 2023-08-31
• Acceptance date: 2023-08-17
• DOI: 10.1093/mnras/stad2597
• EISSN: 1365-2966
• ISSN: 0035-8711
• Language: English
• Keywords: FFR