Combining the CLAUDS and HSC-SSP surveys

Desprez, Guillaume; Picouet, Vincent; Moutard, T.; Arnouts, S.; Sawicki, Marcin; Coupon, J.; Gwyn, Stephen; Chen, L.; Huang, Jiasheng; Golob, Anneya; Furusawa, Hisanori; Ikeda, Hiroyuki; Paltani, S.; Cheng, Cheng; Hartley, W. G.; Hsieh, Bau-Ching; Ilbert, O.; Kauffmann, O. B.; McCracken, H. J.; Shuntov, Marko; Tanaka, Masayuki; Toft, S.; Tresse, L.; Weaver, John R.

doi:10.1051/0004-6361/202243363

Cited by 12 publications

(2 citation statements)

References 86 publications

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“…We provide here starting evidence in terms of QSO number density that AGN can produce a substantial amount of the required ionizing photons to sustain the final phases of the reionization epoch at z ∼ 5. In the future, the RUBICON survey can be extended both in terms of area, within the entire HSC-Wide area (∼1200 deg 2 ), and in terms of depth, thanks to the deep imaging already available in the HSC-Udeep survey (e.g., Desprez et al 2023). If confirmed by future studies, this will have a strong impact on the study of reionization and on the sources responsible for this cosmological event.…”

Section: Discussionmentioning

confidence: 99%

Crossing the Rubicon of Reionization with z ∼ 5 QSOs

Grazian,

Boutsia,

Giallongo

et al. 2023

ApJ

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One of the key open questions in cosmology is the nature of sources that completed cosmological hydrogen reionization at z ∼ 5.2. High-z primeval galaxies have been long considered the main drivers of reionization, with a minor role played by high-z active galactic nuclei (AGN). However, in order to confirm this scenario, it is fundamental to measure the photoionization rate produced by active SMBHs close to the Epoch of Reionization. Given the pivotal role played by spectroscopically complete observations of high-z QSOs, in this paper we present the first results of the RUBICON (Reionizing the Universe with Bright Cosmological Nuclei) survey. It consists of a color-selected sample of bona fide z ∼ 5 QSO candidates from the Hyper Suprime-Cam Subaru Strategic Survey. Our QSO candidates have been validated both by photometric redshifts based on spectral energy distribution fitting and by spectroscopic redshifts, confirming that they lie at 4.5 < z spec < 5.2. A relatively high space density of QSOs (Φ ∼ 1.4 × 10−8 c Mpc−3) is thus confirmed at z ∼ 5 and M 1450 ∼ −27, consistent with a pure density evolution of the AGN luminosity function from z = 4 to z = 5, with a mild density evolution rate of 0.25 dex. This indicates that AGN could play a nonnegligible role in cosmic reionization. The Rubicon of reionization has been crossed.

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Section: Discussionmentioning

confidence: 99%

Crossing the Rubicon of Reionization with z ∼ 5 QSOs

Grazian,

Boutsia,

Giallongo

et al. 2023

ApJ

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“…Paltani et al 2024, in preparation). The configuration is similar to the one using optical and near-infrared photometry prescribed by Desprez et al (2023b), with the addition of the Larson et al (2023) templates and the extension of the explored redshift range to z = 0-15 to better account for high-redshift solutions. A top-hat prior on the rest-frame r-band absolute magnitude between −24 and −7 is adopted.…”

Section: Photometric Redshiftsmentioning

confidence: 99%

A Steep Decline in the Galaxy Space Density beyond Redshift 9 in the CANUCS UV Luminosity Function

Willott,

Desprez,

Asada

et al. 2024

ApJ

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We present a new sample of 158 galaxies at redshift z > 7.5 selected from deep James Webb Space Telescope (JWST) NIRCam imaging of five widely separated sight lines in the CANUCS survey. Two-thirds of the pointings and 80% of the galaxies are covered by 12–14 NIRCam filters, including seven to nine medium bands, providing accurate photometric redshifts and robustness against low-redshift interlopers. A sample of 28 galaxies at z > 7.5 with spectroscopic redshifts shows a low systematic offset and scatter in the difference between photometric and spectroscopic redshifts. We derive the galaxy UV luminosity function at redshifts 8–12, finding a slightly higher normalization than previously seen with the Hubble Space Telescope at redshifts 8–10. We observe a steeper decline in the galaxy space density from z = 8 to 12 than found by most JWST Cycle 1 studies. In particular, we find only eight galaxies at z > 10 and none at z > 12.5, with no z > 10 galaxies brighter than F277W AB = 28 or M UV = −20 in our unmasked, delensed survey area of 53.4 arcmin2. We attribute the lack of bright z > 10 galaxies in CANUCS compared to GLASS and CEERS to intrinsic variance in the galaxy density along different sight lines. The evolution in the CANUCS luminosity function between z = 8 and 12 is comparable to that predicted by simulations that assume a standard star formation efficiency without invoking any special adjustments.

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HSC-CLAUDS survey: The star formation rate functions since z ∼ 2 and comparison with hydrodynamical simulations

Picouet,

Arnouts,

Le Floc’h

et al. 2023

A&A

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Context. Star formation rate functions (SFRFs) give an instantaneous view of the distribution of star formation rates (SFRs) in galaxies at different epochs. They are a complementary and more stringent test for models than the galaxy stellar mass function, which gives an integrated view of the past star formation activity. However, the exploration of SFRFs has been limited thus far due to difficulties in assessing the SFR from observed quantities and probing the SFRF over a wide range of SFRs. Aims. We overcome these limitations thanks to an original method that predicts the infrared luminosity from the rest-frame UV/optical color of a galaxy and then its SFR over a wide range of stellar masses and redshifts. We applied this technique to the deep imaging survey HSC-CLAUDS combined with near-infrared and UV photometry. We provide the first SFR functions with reliable measurements in the high- and low-SFR regimes up to z = 2 and compare our results with previous observations and four state-of-the-art hydrodynamical simulations. Methods. The SFR estimates are based on the calibration of the infrared excess (IRX = LIR/LUV) in the NUVrK color-color diagram. We improved upon the original calibration in the COSMOS field by incorporating Herschel photometry, which allowed us to extend the analysis to higher redshifts and to galaxies with lower stellar masses using stacking techniques. Our NrK method leads to an accuracy of individual SFR estimates of σ ∼ 0.25 dex. We show that it reproduces the evolution of the main sequence up to z = 2 and the behavior of the attenuation (or ⟨IRX⟩) with stellar mass. In addition to the known lack of evolution of this relation up to z = 2 for galaxies with M⋆ ≤ 1010.3 M⊙, we observe a plateau in ⟨IRX⟩ at higher stellar masses that depends on redshift. Results. We measure the SFR functions and cosmic SFR density up to z = 2 for a mass-selected star-forming galaxy sample (with a mass limit of M⋆ ≥ 2.109 M⊙ at z = 2). The SFR functions cover a wide range of SFRs (0.01 ≤ SFR ≤ 1000 M⊙ yr−1), providing good constraints on their shapes. They are well fitted by a Schechter function after accounting for the Eddington bias. The high-SFR tails match the far-infrared observations well, and show a strong redshift evolution of the Schechter parameter, SFR⋆, as log10(SFR⋆) = 5.8z + 0.76. The slope of the SFR functions, α, shows almost no evolution up to z = 1.5 − 2 with α = −1.3 ± 0.1. We compare the SFR functions with predictions from four state-of-the-art hydrodynamical simulations. Significant differences are observed between them, and none of the simulations are able to reproduce the observed SFRFs over the whole redshift and SFR range. We find that only one simulation is able to predict the fraction of highly star-forming galaxies at high z, 1 ≤ z ≤ 2. This highlights the benefits of using SFRFs as a constraint that can be reproduced by simulations; however, despite efforts to incorporate more physically motivated prescriptions for star-formation and feedback processes, its use remains challenging.

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Combining the CLAUDS and HSC-SSP surveys

Cited by 12 publications

References 86 publications

Crossing the Rubicon of Reionization with z ∼ 5 QSOs

Crossing the Rubicon of Reionization with z ∼ 5 QSOs

A Steep Decline in the Galaxy Space Density beyond Redshift 9 in the CANUCS UV Luminosity Function

HSC-CLAUDS survey: The star formation rate functions since z ∼ 2 and comparison with hydrodynamical simulations

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