Predicting emission line fluxes and number counts of distant galaxies for cosmological surveys
Open access
Datum
2017-12Typ
- Journal Article
ETH Bibliographie
yes
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Abstract
We estimate the number counts of line emitters at high redshift and their evolution with
cosmic time based on a combination of photometry and spectroscopy. We predict the H α,
H β, [O II], and [O III] line fluxes for more than 35 000 galaxies down to stellar masses of
∼109 M in the COSMOS and GOODS-S fields, applying standard conversions and exploit ing the spectroscopic coverage of the FMOS-COSMOS survey at z ∼ 1.55 to calibrate the
predictions. We calculate the number counts of H α, [O II], and [O III] emitters down to fluxes
of 1 × 10−17 erg cm−2 s−1 in the range 1.4 < z < 1.8 covered by the FMOS-COSMOS survey.
We model the time evolution of the differential and cumulative H α counts, steeply declining
at the brightest fluxes. We expect ∼9300–9700 and ∼2300–2900 galaxies deg−2 for fluxes
≥1 × 10−16 and ≥2 × 10−16 erg cm−2 s−1 over the range of 0.9 < z < 1.8. We show that
the observed evolution of the main sequence of galaxies with redshift is enough to reproduce
the observed counts variation at 0.2 < z < 2.5. We characterize the physical properties of the
H α emitters with fluxes ≥2 × 10−16 erg cm−2 s−1 including their stellar masses, UV sizes,
[N II]/H α ratios and H α equivalent widths. An aperture of R ∼ Re ∼ 0.5 arcsec maximizes the
signal-to-noise ratio for a detection, whilst causing a factor of ∼2 × flux losses, influencing the
recoverable number counts, if neglected. Our approach, based on deep and large photometric
data sets, reduces the uncertainties on the number counts due to the selection and spectroscopic
samplings whilst exploring low fluxes. We publicly release the line flux predictions for the
explored photometric samples. Mehr anzeigen
Persistenter Link
https://doi.org/10.3929/ethz-b-000220132Publikationsstatus
publishedExterne Links
Zeitschrift / Serie
Monthly Notices of the Royal Astronomical SocietyBand
Seiten / Artikelnummer
Verlag
Oxford University PressThema
galaxies: distances and redshifts; galaxies: high-redshift; galaxies: star; formation; galaxies: statistics; large-scale structure of Universe; cosmology: observationsOrganisationseinheit
03613 - Lilly, Simon (emeritus) / Lilly, Simon (emeritus)
Anmerkungen
It was possible to publish this article open access thanks to a Swiss National Licence with the publisher.ETH Bibliographie
yes
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