The SAMI galaxy survey: predicting kinematic morphology with logistic regression ...

• Main Authors: Vaughan, Sam P., van de Sande, Jesse, Fraser-McKelvie, A., Croom, Scott, McDermid, Richard, Liquet-Weiland, Benoit, Barsanti, Stefania, Cortese, Luca, Brough, Sarah, Sweet, Sarah, Bryant, Julia J., Goodwin, Michael, Lawrence, Jon
• Format: Report
• Language: unknown
• Published: arXiv 2024
• Subjects: Astrophysics of Galaxies astro-ph.GA; FOS Physical sciences; sami
• Online Access: https://dx.doi.org/10.48550/arxiv.2402.03676; https://arxiv.org/abs/2402.03676

We use the SAMI galaxy survey to study the the kinematic morphology-density relation: the observation that the fraction of slow rotator galaxies increases towards dense environments. We build a logistic regression model to quantitatively study the dependence of kinematic morphology (whether a galaxy is a fast rotator or slow rotator) on a wide range of parameters, without resorting to binning the data. Our model uses a combination of stellar mass, star-formation rate (SFR), $r$-band half-light radius and a binary variable based on whether the galaxy's observed ellipticity ($ε$) is less than 0.4. We show that, at fixed mass, size, SFR and $ε$, a galaxy's local environmental surface density ($\log_{10}(Σ_5/\mathrm{Mpc}^{-2})$) gives no further information about whether a galaxy is a slow rotator, i.e. the observed kinematic-morphology density relation can be entirely explained by the well-known correlations between environment and other quantities. We show how our model can be applied to different galaxy ... : 12 pages, 6 figures. Accepted for publication in MNRAS ...