http://arxiv.org/abs/2201.05285
Derivation of physical properties of galaxies using spectral energy distribution (SED) fitting is a powerful method, but can suffer from various systematics arising from model assumptions. Previously, such biases were mostly studied for individual galaxies. Here we specifically study a large sample (9000) of composite (merged) galaxies extracted from GALEX-SDSS-WISE Legacy Catalog (GSWLC) in order to check if SED fitting accurately determines the properties (stellar mass and star formation rate) of an unresolved merged galaxy. We carry out the assessment by artificially merging the galaxies that could merge in reality and running UV/optical SED fitting on them as well as on pre-merger individual galaxies (to establish ground truth). With this simple approach we know what mass and SFR to ideally expect for the merger. No biases are found when comparing the stellar mass, star formation rate (SFR), and specific star formation rate (sSFR) values from the SED fitting to the combined values from the individual galaxies, although there are tails in the SFR and sSFR merger comparisons with low (s)SFR. Furthermore, no significant residuals were found when focusing on galaxies with different mass ratios (major vs.\ minor mergers), different contrasts in SFR, or dust content. We conclude that the SED fitting of post-mergers does not suffer from significant biases that would arise from the fact that the merger is a composite of two galaxies with potentially very different star formation histories and with different dust properties.
K. Zine and S. Salim
Mon, 17 Jan 22
58/59
Comments: Submitted to ApJ
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