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Less is less: photometry alone cannot predict the observed spectral indices of $z\sim1$ galaxies from the LEGA-C spectroscopic survey by Nersesian, Angelos; van der Wel, Arjen; Gallazzi, Anna; Leja, Joel; Bezanson, Rachel; Bell, Eric F.; D'Eugenio, Francesco; de Graaff, Anna; Kaushal, Yasha; Martorano, Marco; Maseda, Michael; Zibetti, Stefano is a scholarly article available to read on EtoBox.

What is Less is less: photometry alone cannot predict the observed spectral indices of $z\sim1$ galaxies from the LEGA-C spectroscopic survey about?

We test whether we can predict optical spectra from deep-field photometry of distant galaxies. Our goal is to perform a comparison in data space, highlighting the differences between predicted and observed spectra. The Large Early Galaxy Astrophysics Census (LEGA-C) provides high-quality optical spectra of thousands of galaxies at redshift $0.6<z<1$. Broad-band photometry of the same galaxies, drawn from the recent COSMOS2020 catalog, is used to predict the optical spectra with the spectral energy distribution (SED) fitting code Prospector and the MILES stellar library. The observed and predicted spectra are compared in terms of two age and metallicity-sensitive absorption features (H$\delta_\mathrm{A}$ and Fe4383). The global bimodality of star-forming and quiescent galaxies in photometric space is recovered with the model spectra. But the presence of a systematic offset in the Fe4383 line strength and the weak correlation between the observed and modeled line strength imply that accurate age or metallicity determinations cannot be inferred from photometry alone. For now we caution that photometry-based estimates of stellar population properties are determined mostly by the modeli

Author

Nersesian, Angelos; van der Wel, Arjen; Gallazzi, Anna; Leja, Joel; Bezanson, Rachel; Bell, Eric F.; D'Eugenio, Francesco; de Graaff, Anna; Kaushal, Yasha; Martorano, Marco; Maseda, Michael; Zibetti, Stefano

Published

2023

Language

EN