The clustering of H β\beta + [O III] and [O II] emitters since z \tilde 5: dependencies with line luminosity and stellar mass

We investigate the clustering properties of ∼7000 H β + [O III] and [O II] narrowband-selected emitters at z ∼ 0.8–4.7 from the High-z Emission Line Survey. We find clustering lengths, r0, of 1.5–4.0 h−1 Mpc and minimum dark matter halo masses of 1010.7–12.1 M⊙ for our z = 0.8–3.2 H β + [O III] emitters and r0 ∼ 2.0–8.3 h−1 Mpc and halo masses of 1011.5–12.6 M⊙ for our z = 1.5–4.7 [O II] emitters. We find r0 to strongly increase both with increasing line luminosity and redshift. By taking into account the evolution of the characteristic line luminosity, L⋆(z), and using our model predictions of halo mass given r0, we find a strong, redshift-independent increasing trend between L/L⋆(z) and minimum halo mass. The faintest H β + [O III] emitters are found to reside in 109.5 M⊙ haloes and the brightest emitters in 1013.0 M⊙ haloes. For [O II] emitters, the faintest emitters are found in 1010.5 M⊙ haloes and the brightest emitters in 1012.6 M⊙ haloes. A redshift-independent stellar mass dependency is also observed where the halo mass increases from 1011 to 1012.5 M⊙ for stellar masses of 108.5 to 1011.5 M⊙, respectively. We investigate the interdependencies of these trends by repeating our analysis in a Lline−Mstar grid space for our most populated samples (H β + [O III] z = 0.84 and [O II] z = 1.47) and find that the line luminosity dependency is stronger than the stellar mass dependency on halo mass. For L > L⋆ emitters at all epochs, we find a relatively flat trend with halo masses of 1012.5–13 M⊙, which may be due to quenching mechanisms in massive haloes that is consistent with a transitional halo mass predicted by models

The evolution of the UV luminosity and stellar mass functions of Lyman-α emitters from z ~2 to z ~6

We measure the evolution of the rest-frame UV luminosity function (LF) and the stellar mass function (SMF) of Lyman-α (Ly α) emitters (LAEs) from z ~ 2 to z ~ 6 by exploring ~4000 LAEs from the SC4K sample. We find a correlation between Ly α luminosity (LLy α) and rest-frame UV (MUV), with best fit MUV = -1.6+0.2-0.3 log10(LLy α/erg s-1) + 47+12-11 and a shallower relation between LLy α and stellar mass (M∗), with best fit log10(M∗/M·) = 0.9+0.1-0.1 log10(LLy α/erg s-1) - 28+4.0-3.8. An increasing LLy α cut predominantly lowers the number density of faint MUV and low M∗ LAEs. We estimate a proxy for the full UV LFs and SMFs of LAEs with simple assumptions of the faint end slope. For the UV LF, we find a brightening of the characteristic UV luminosity (M∗UV) with increasing redshift and a decrease of the characteristic number density (Φ∗). For the SMF, we measure a characteristic stellar mass (M∗∗/M·) increase with increasing redshift, and a Φ∗ decline. However, if we apply a uniform luminosity cut of log10(LLy α/erg s-1) ≥ 43.0, we find much milder to no evolution in the UV and SMF of LAEs. The UV luminosity density (ρUV) of the full sample of LAEs shows moderate evolution and the stellar mass density (ρM) decreases, with both being always lower than the total ρUV and ρM of more typical galaxies but slowly approaching them with increasing redshift. Overall, our results indicate that both ρUV and ρM of LAEs slowly approach the measurements of continuum-selected galaxies at z > 6, which suggests a key role of LAEs in the epoch of reionization

Variation of the nebular dust attenuation curve with the properties of local star-forming galaxies

We use a sample of 78 340 star-forming galaxies at z ∼ 0.04-0.1 from the Sloan Digital Sky Survey (SDSS) data release (DR8) survey to calculate the average nebular dust attenuation curve and its variation with the physical properties of galaxies. Using the first four low-order Balmer emission lines (H α, H β, H γ, and H δ) detected in the composite spectrum of all galaxies in the sample, we derive a nebular attenuation curve in the range of 0.41 to 0.66, μm that has a similar shape and normalization to that of the Galactic extinction curve (Milky Way curve), the SMC curve and the nebular attenuation curve derived recently for typical star-forming galaxies at z ∼2. We divide the galaxies into bins of stellar mass, gas-phase metallicity, and specific star formation rate, and derive the nebular attenuation curve in each of these bins. This analysis indicates that there is very little variation in the shape of the nebular dust attenuation curve with the properties used to bin the galaxies, and suggests a near universal shape of the nebular dust attenuation curve at least among the galaxies and the range of properties considered in our sample. © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Evolution of the H β + [O III] and [O II] luminosity functions and the [O II] star formation history of the Universe up to z ∼ 5 from HiZELS

We investigate the evolution of the H β + [O iii] and [O ii] luminosity functions from z ∼ 0.8 to ∼5 in four redshift slices per emission line using data from the High-z Emission Line Survey (HiZELS). This is the first time that the H β + [O iii] and [O ii] luminosity functions have been studied at these redshifts in a self-consistent analysis. This is also the largest sample of [O ii] and H β + [O iii] emitters (3475 and 3298 emitters, respectively) in this redshift range, with large comoving volumes ∼1 × 106 Mpc−3 in two independent volumes (COSMOS and UDS), greatly reducing the effects of cosmic variance. The emitters were selected by a combination of photometric redshift and colour–colour selections, as well as spectroscopic follow-up, including recent spectroscopic observations using DEIMOS and MOSFIRE on the Keck Telescopes and FMOS on Subaru. We find a strong increase in L⋆ and a decrease in ϕ⋆ for both H β + [O iii] and [O ii] emitters. We derive the [O ii] star formation history of the Universe since z ∼ 5 and find that the cosmic star formation rate density (SFRD) rises from z ∼ 5 to ∼3 and then drops towards z ∼ 0. We also find that our star formation history is able to reproduce the evolution of the stellar mass density up to z ∼ 5 based only on a single tracer of star formation. When comparing the H β + [O iii] SFRDs to the [O ii] and H α SFRD measurements in the literature, we find that there is a remarkable agreement, suggesting that the H β + [O iii] sample is dominated by star-forming galaxies at high-z rather than AGNs

Slicing COSMOS with SC4K: the evolution of typical Lyα emitters and the Lyα escape fraction from z ~ 2 to z ~ 6

Large scale structure and cosmolog

The nature of Hβ+[O III] and [O II] emitters to z ∼ 5 with HiZELS: stellar mass functions and the evolution of EWs

We investigate the properties of ∼7000 narrow-band selected galaxies with strong Hβ+[O III] and [O II] nebular emission lines from the High-z Emission-Line Survey between z ∼ 0.8 and 5.0. Our sample covers a wide range in stellar mass (Mstellar ∼ 107.5–12.0 M⊙), rest-frame equivalent widths (EWrest∼10–105 Å), and line luminosities (Lline ∼ 1040.5–43.2 erg s−1). We measure the Hβ+[O III]-selected stellar mass functions out to z ∼ 3.5 and find that both M⋆ and ϕ⋆ increases with cosmic time. The [O II]-selected stellar mass functions show a constant M⋆ ≈ 1011.6 M⊙ and a strong, increasing evolution with cosmic time in ϕ⋆ in line with Hα studies. We also investigate the evolution of the EWrest as a function of redshift with a fixed mass range (109.5–10.0 M⊙) and find an increasing trend best represented by (1 + z)3.81 ± 0.14 and (1 + z)2.72 ± 0.19 up to z ∼ 2 and ∼3 for Hβ+[O III] and [O II] emitters, respectively. This is the first time that the EWrest evolution has been directly measured for Hβ+[O III] and [O II] emitters up to these redshifts. There is evidence for a slower evolution for z > 2 in the Hβ+[O III] EWrest and a decreasing trend for z > 3 in the [O II] EWrest evolution, which would imply low [O II] EW at the highest redshifts and higher [O III]/[O II] line ratios. This suggests that the ionization parameter at higher redshift may be significantly higher than the local Universe. Our results set the stage for future near-IR space-based spectroscopic surveys to test our extrapolated predictions and also produce z > 5 measurements to constrain the high-z end of the EWrest and [O III]/[O II] evolution

CF-HiZELS, an ∼10 deg2 emission-line survey with spectroscopic follow-up: Hα, [O iii] + Hβ and [O ii] luminosity functions at z = 0.8, 1.4 and 2.2

We present results from the largest contiguous narrow-band survey in the near-infrared. We have used the wide-field infrared camera/Canada–France–Hawaii Telescope and the lowOH2 filter (1.187 ± 0.005 μm) to survey ≈10 deg2 of contiguous extragalactic sky in the SA22 field. A total of ∼6000 candidate emission-line galaxies are found. We use deep ugrizJK data to obtain robust photometric redshifts. We combine our data with the High-redshift(Z) Emission Line Survey (HiZELS), explore spectroscopic surveys (VVDS, VIPERS) and obtain our own spectroscopic follow-up with KMOS, FMOS and MOSFIRE to derive large samples of high-redshift emission-line selected galaxies: 3471 Hα emitters at z = 0.8, 1343 [O iii] + Hβ emitters at z = 1.4 and 572 [O ii] emitters at z = 2.2. We probe comoving volumes of >106 Mpc3 and find significant overdensities, including an 8.5σ (spectroscopically confirmed) overdensity of Hα emitters at z = 0.81. We derive Hα, [O iii] + Hβ and [O ii] luminosity functions at z = 0.8, 1.4, 2.2, respectively, and present implications for future surveys such as Euclid. Our uniquely large volumes/areas allow us to subdivide the samples in thousands of randomized combinations of areas and provide a robust empirical measurement of sample/cosmic variance. We show that surveys for star-forming/emission-line galaxies at a depth similar to ours can only overcome cosmic-variance (errors 5 × 105 Mpc3; errors on L* and ϕ* due to sample (cosmic) variance on surveys probing ∼104 and ∼105 Mpc3 are typically very high: ∼300 and ∼40–60 per cent, respectively

[O III] emission line as a tracer of star-forming galaxies at high redshifts: comparison between Hα and [O III] emitters at z=2.23 in HiZELS

We investigate the properties of z = 2.23 Hα and [O III] λ5007 emitters using the narrow-band-selected samples obtained from the High-z Emission Line Survey. We construct two samples of the Hα and [O III] emitters and compare their integrated physical properties. We find that the distribution of stellar masses, dust extinction, star formation rates (SFRs), and specific SFRs (sSFRs) is not statistically different between the two samples. When we separate the full galaxy sample into three subsamples according to the detections of the Hα and/or [O III] emission lines, most of the sources detected with both Hα and [O III] show log(sSFRUV) ≳ −9.5. The comparison of the three subsamples suggests that sources with strong [O III] line emission tend to have the highest star-forming activity out all galaxies that we study. We argue that the [O III] emission line can be used as a tracer of star-forming galaxies at high redshift, and that it is especially useful to investigate star-forming galaxies at z > 3, for which Hα emission is no longer observable from the ground

Spitzer Imaging of Herschel-atlas Gravitationally Lensed Submillimeter Sources

Original article can be found at: http://www.iop.org/EJ/journal/apjl Copyright American Astronomical Society[Full text of this article is not available in the UHRA]We present physical properties of two submillimeter selected gravitationally lensed sources, identified in the Herschel Astrophysical Terahertz Large Area Survey. These submillimeter galaxies (SMGs) have flux densities >100 mJy at 500 mu m, but are not visible in existing optical imaging. We fit light profiles to each component of the lensing systems in Spitzer IRAC 3.6 and 4.5 mu m data and successfully disentangle the foreground lens from the background source in each case, providing important constraints on the spectral energy distributions (SEDs) of the background SMG at rest-frame optical-near-infrared wavelengths. The SED fits show that these two SMGs have high dust obscuration with A(V) similar to 4-5 and star formation rates of similar to 100M(circle dot) yr(-1). They have low gas fractions and low dynamical masses compared with 850 mu m selected galaxies.Peer reviewe