Dark-ages reionization and galaxy-formation simulation – VII. The sizes of high-redshift galaxies

Liu, Chuanwu; Mutch, Simon J.; Poole, Gregory B.; Angel, Paul W.; Duffy, Alan R.; Geil, Paul M.; Mesinger, Andrei; Wyithe, J. Stuart B.

doi:10.1093/mnras/stw2912

Cited by 28 publications

(34 citation statements)

References 84 publications

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“…Fitting their SEDs with simple models results in a mass of the order of 10 8 M , in which case they should be high-z galaxies rather than clumps. The typical size of these objects is ∼ 0.4 arcsec, which is consistent with typical sizes of high-z galaxies as found by (Bouwens et al 2004;Oesch et al 2010;Ono et al 2013;Shibuya et al 2015;Holwerda et al 2015;Liu et al 2017). Moreover, luminous clumps in clumpy galaxies are usually surrounded by a common isophote, embedding the entire galaxy, below the bright level of the clumps but above the background sky (see Hinojosa-Goñi et al 2016).…”

Section: Pair Groups and Overdensitiessupporting

confidence: 84%

A simultaneous search for high-z LAEs and LBGs in the SHARDS survey

Haro

Espinosa

Muñoz–Tuñón

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We have undertaken a comprehensive search for both Lyman Alpha Emitters (LAEs) and Lyman Break Galaxies (LBGs) in the SHARDS Survey of the GOODS-N field. SHARDS is a deep imaging survey, made with the 10.4 m Gran Telescopio Canarias (GTC), employing 25 medium band filters in the range from 500 to 941 nm. This is the first time that both LAEs and LBGs are surveyed simultaneously in a systematic way in a large field. We draw a sample of 1558 sources; 528 of them are LAEs. Most of the sources (1434) show rest-frame UV continua. A minority of them (124) are pure LAEs with virtually no continuum detected in SHARDS. We study these sources from z ∼ 3.35 up to z ∼ 6.8, well into the epoch of reionization. Note that surveys done with just one or two narrow band filters lack the possibility to spot the rest-frame UV continuum present in most of our LAEs. We derive redshifts, Star Formation Rates (SFRs), Lyα Equivalent Widths (EWs) and Luminosity Functions (LFs). Grouping within our sample is also studied, finding 92 pairs or small groups of galaxies at the same redshift separated by less than 60 comoving kpc. In addition, we relate 87 and 55 UV-selected objects with two known overdensities at z = 4.05 and z = 5.198, respectively. Finally, we show that surveys made with broad band filters are prone to introduce many unwanted sources (∼ 20% interlopers), which means that previous studies may be overestimating the calculated LFs, specially at the faint end.

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Section: Pair Groups and Overdensitiessupporting

confidence: 84%

A simultaneous search for high-z LAEs and LBGs in the SHARDS survey

Haro

Espinosa

Muñoz–Tuñón

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…The DM haloes then have galaxy properties applied with a bespoke SAM, meraxes (Mutch et al 2016a), which includes coupled photoionization feedback through an excursion set scheme 21cmfast (Mesinger et al 2011) to track reionization. Meraxes has successfully reproduced existing observations at high-redshifts (5 < z < 10) of the luminosity and stellar mass functions (Liu et al 2016), sizes of galaxies (Liu et al 2017) as well as predicted the reionization structure of the intergalactic medium around the growing galaxies ).…”

Section: Simulation Detailssupporting

confidence: 62%

Dark-ages reionization and galaxy formation simulation – IX. Economics of reionizing galaxies

Duffy

Mutch

Poole

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Using a series of high-resolution hydrodynamical simulations we show that during the rapid growth of high-redshift (z > 5) galaxies, reserves of molecular gas are consumed over a time-scale of 300 Myr almost independent of feedback scheme. We find that there exists no such simple relation for the total gas fractions of these galaxies, with little correlation between gas fractions and specific star formation rates. The bottleneck or limiting factor in the growth of early galaxies is in converting infalling gas to cold star-forming gas. Thus, we find that the majority of high-redshift dwarf galaxies are effectively in recession, with demand (of star formation) never rising to meet supply (of gas), irrespective of the baryonic feedback physics modelled. We conclude that the basic assumption of self-regulation in galaxies -that they can adjust total gas consumption within a Hubble time -does not apply for the dwarf galaxies thought to be responsible for providing most UV photons to reionize the high-redshift Universe. We demonstrate how this rapid molecular time-scale improves agreement between semi-analytic model predictions of the early Universe and observed stellar mass functions.

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“…Also, no discernible dependence was found for the measured surface densities as a function of the predicted shear in the highmagnification regions. Nonetheless, becausesuch small sizes for galaxies are unexpected (e.g., Liu et al 2017;Kravtsov 2013), we also consider the impact of larger sizes (and a larger incompleteness) on the LF results throughout the paper.…”

Section: Appendix B Selection Volume Estimatesmentioning

confidence: 99%

The z ∼ 6 Luminosity Function Fainter than −15 mag from the Hubble Frontier Fields: The Impact of Magnification Uncertainties

Bouwens

Oesch

Illingworth

et al. 2017

ApJ

284

428

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We use the largest sample of z 6 galaxies to date from the first four Hubble Frontier Fields clusters to set constraints on the shape of the z 6 luminosity functions (LFs) to fainter than M 14 AB UV, = -mag. We quantify, for the first time, the impact of magnification uncertainties on LF results and thus provide more realistic constraints than other recent work. Our simulations reveal that, for the highly magnified sources, the systematic uncertainties can become extremely large fainter than −14 mag, reaching several orders of magnitude at 95% confidence at approximately−12 mag. Our new forward-modeling formalism incorporates the impact of magnification uncertainties into the LF results by exploiting the availability of many independent magnification models for the same cluster. One public magnification model is used to construct a mock high-redshift galaxy sample that is then analyzed using the other magnification models to construct an LF. Large systematic errors occur at high magnifications ( 30  m ) because of differences between the models. The volume densities we derive for faint (−17 mag) sources are ∼3-4× lower than one recent report and give a faint-end slope 1.92 0.04 a = - , which is 3.0-3.5σ shallower (including or not including the size uncertainties, respectively). We introduce a new curvature parameter δ to model the faint end of the LF and demonstrate that the observations permit (at 68% confidence) a turn-over at z 6 in the range of −15.3 to −14.2 mag, depending on the assumed lensing model. The present consideration of magnification errors and new size determinations raise doubts about previous reports regarding the form of the LF at 14 mag >-. We discuss the implications of our turn-over constraints in the context of recent theoretical predictions.

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Dark-ages reionization and galaxy-formation simulation – VII. The sizes of high-redshift galaxies

Cited by 28 publications

References 84 publications

A simultaneous search for high-z LAEs and LBGs in the SHARDS survey

A simultaneous search for high-z LAEs and LBGs in the SHARDS survey

Dark-ages reionization and galaxy formation simulation – IX. Economics of reionizing galaxies

The z ∼ 6 Luminosity Function Fainter than −15 mag from the Hubble Frontier Fields: The Impact of Magnification Uncertainties

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