Less is less: Photometry alone cannot predict the observed spectral indices of z ~ 1 galaxies from the LEGA-C spectroscopic survey
- Author
- Angelos Nersesian, Arjen van der Wel (UGent) , Anna Gallazzi, Joel Leja, Rachel Bezanson, Eric F. Bell, Francesco D’Eugenio, Anna de Graaff, Yasha Kaushal, Marco Martorano, Michael Maseda and Stefano Zibetti
- Organization
- Abstract
- <jats:p><jats:italic>Aims</jats:italic>. 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.</jats:p> <jats:p><jats:italic>Methods</jats:italic>. The Large Early Galaxy Astrophysics Census (LEGA-C) provides high-quality optical spectra of thousands of galaxies at redshift 0.6 < <jats:italic>z</jats:italic> < 1. Broadband 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<jats:italic>δ</jats:italic><jats:sub>A</jats:sub> and Fe4383).</jats:p> <jats:p><jats:italic>Results</jats:italic>. The global bimodality of star-forming and quiescent galaxies in photometric space is recovered with the model spectra. However, 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.</jats:p> <jats:p><jats:italic>Conclusions</jats:italic>. For now we caution that photometry-based estimates of stellar population properties are determined mostly by the modeling approach and not the physical properties of galaxies, even when using the highest-quality photometric datasets and state-of-the-art fitting techniques. When exploring a new physical parameter space (i.e. redshift or galaxy mass) high-quality spectroscopy is always needed to inform the analysis of photometry.</jats:p>
Citation
Please use this url to cite or link to this publication: http://hdl.handle.net/1854/LU-01JERCJQ2GJ4JBJHN9BWW1677G
- MLA
- Nersesian, Angelos, et al. “Less Is Less: Photometry Alone Cannot Predict the Observed Spectral Indices of z ~ 1 Galaxies from the LEGA-C Spectroscopic Survey.” Astronomy & Astrophysics, vol. 681, EDP Sciences, 2024, p. A94, doi:10.1051/0004-6361/202346769.
- APA
- Nersesian, A., van der Wel, A., Gallazzi, A., Leja, J., Bezanson, R., Bell, E. F., … Zibetti, S. (2024). Less is less: Photometry alone cannot predict the observed spectral indices of z ~ 1 galaxies from the LEGA-C spectroscopic survey. Astronomy & Astrophysics, 681, A94. https://doi.org/10.1051/0004-6361/202346769
- Chicago author-date
- Nersesian, Angelos, Arjen van der Wel, Anna Gallazzi, Joel Leja, Rachel Bezanson, Eric F. Bell, Francesco D’Eugenio, et al. 2024. “Less Is Less: Photometry Alone Cannot Predict the Observed Spectral Indices of z ~ 1 Galaxies from the LEGA-C Spectroscopic Survey.” Astronomy & Astrophysics 681: A94. https://doi.org/10.1051/0004-6361/202346769.
- Chicago author-date (all authors)
- Nersesian, Angelos, Arjen van der Wel, Anna Gallazzi, Joel Leja, Rachel Bezanson, Eric F. Bell, Francesco D’Eugenio, Anna de Graaff, Yasha Kaushal, Marco Martorano, Michael Maseda, and Stefano Zibetti. 2024. “Less Is Less: Photometry Alone Cannot Predict the Observed Spectral Indices of z ~ 1 Galaxies from the LEGA-C Spectroscopic Survey.” Astronomy & Astrophysics 681: A94. doi:10.1051/0004-6361/202346769.
- Vancouver
- 1.Nersesian A, van der Wel A, Gallazzi A, Leja J, Bezanson R, Bell EF, et al. Less is less: Photometry alone cannot predict the observed spectral indices of z ~ 1 galaxies from the LEGA-C spectroscopic survey. Astronomy & Astrophysics. 2024;681:A94.
- IEEE
- [1]A. Nersesian et al., “Less is less: Photometry alone cannot predict the observed spectral indices of z ~ 1 galaxies from the LEGA-C spectroscopic survey,” Astronomy & Astrophysics, vol. 681, p. A94, 2024.
@article{01JERCJQ2GJ4JBJHN9BWW1677G,
abstract = {{<jats:p><jats:italic>Aims</jats:italic>. 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.</jats:p>
<jats:p><jats:italic>Methods</jats:italic>. The Large Early Galaxy Astrophysics Census (LEGA-C) provides high-quality optical spectra of thousands of galaxies at redshift 0.6 < <jats:italic>z</jats:italic> < 1. Broadband 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<jats:italic>δ</jats:italic><jats:sub>A</jats:sub> and Fe4383).</jats:p>
<jats:p><jats:italic>Results</jats:italic>. The global bimodality of star-forming and quiescent galaxies in photometric space is recovered with the model spectra. However, 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.</jats:p>
<jats:p><jats:italic>Conclusions</jats:italic>. For now we caution that photometry-based estimates of stellar population properties are determined mostly by the modeling approach and not the physical properties of galaxies, even when using the highest-quality photometric datasets and state-of-the-art fitting techniques. When exploring a new physical parameter space (i.e. redshift or galaxy mass) high-quality spectroscopy is always needed to inform the analysis of photometry.</jats:p>}},
author = {{Nersesian, Angelos and van der Wel, Arjen and Gallazzi, Anna and Leja, Joel and Bezanson, Rachel and Bell, Eric F. and D’Eugenio, Francesco and de Graaff, Anna and Kaushal, Yasha and Martorano, Marco and Maseda, Michael and Zibetti, Stefano}},
issn = {{0004-6361}},
journal = {{Astronomy & Astrophysics}},
language = {{und}},
publisher = {{EDP Sciences}},
title = {{Less is less: Photometry alone cannot predict the observed spectral indices of z ~ 1 galaxies from the LEGA-C spectroscopic survey}},
url = {{http://doi.org/10.1051/0004-6361/202346769}},
volume = {{681}},
year = {{2024}},
}
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