The HDUV Survey: Six Lyman Continuum Emitter Candidates at z ∼ 2 Revealed by HST UV Imaging*

Naidu, Rohan P.; Oesch, Pascal; Reddy, Naveen A.; Holden, B. P.; Steidel, Charles C.; Montes, Mireia; Atek, Hakim; Carollo, C. M.; Cibinel, A.; Illingworth, G. D.; Labbé, Ivo; Magee, D.; Morselli, L.; Nelson, Erica J.; Dokkum, Pieter van; Wilkins, Stephen M.

doi:10.3847/1538-4357/aa8863

Cited by 34 publications

(53 citation statements)

References 113 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The depths of the F275W and F336W bands are 27.6 and 28.0 (5σ), respectively. The deep F275W and F336W images from the HDUV survey have been used to study the LyC escape fraction in galaxies at z ∼ 2 and z ∼ 3, respectively (Naidu et al 2017;Rutkowski et al 2017;Japelj et al 2017). In particular, Japelj et al (2017) studied the LyC escape fraction in a sample of galaxies at z = 3 − 4 selected in 9 arcmin 2 MUSE HUDF survey field using the HDUV F336W image and found the relative escape fraction f esc,rel < 0.6 for galaxies with 0.1L * .…”

Section: Sample Selectionmentioning

confidence: 99%

“…Thus we have to infer the LyC escape in the galaxies at the epoch of the reioisation based on either directly measuring LyC escape fraction in galaxies at lower redshift or correlating galaxy spatial positions with the Lyman alpha forest at z > 6 (e.g., Kakiichi et al 2018). In the last decade, people have conducted extensive studies of LyC escape fraction in galaxies at z < 4 using a number of different approaches, including the rest-frame ultraviolet spectroscopy (e.g., Leitet et al 2013;Leitherer et al 2016;Izotov et al 2016b,a;Steidel et al 2001Steidel et al , 2018Shapley et al 2006Shapley et al , 2016Nestor et al 2013) and narrow/intermediate/broad-band UV imaging (e.g., Siana et al 2007Siana et al , 2015Vanzella et al 2010Vanzella et al , 2016Nestor et al 2011;Cooke et al 2014;Rutkowski et al 2016Rutkowski et al , 2017Vasei et al 2016;Bian et al 2017;Japelj et al 2017;Naidu et al 2017;Fletcher et al 2018;Ji et al 2019). However, accurately measuring the escape fraction remains difficult.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Lyman continuum escape fraction in Ly α emitters at z ≃ 3.1

Bian

Fan

2020

Monthly Notices of the Royal Astronomical Society: Letters

View full text Add to dashboard Cite

We measure the LyC escape fraction in 54 faint Lyman Alpha Emitters (LAEs) at z ≃ 3.1 in the GOODS-South field. With the average magnitude of R = 26.7 AB (M UV = −18.8, L ≃ 0.1L * ), these galaxies represent a population of compact young dwarf galaxies. Their properties are likely to resemble those in the galaxies responsible for reionising the Universe at z > 6. We do not detect LyC emission in any individual LAEs in the deep HST F336W images, which covers the rest-frame 820Å. We do not detect the LyC emission of these LAEs in the stacked F336W images, either. The 3σ upper limit of LyC escape fractions is f esc < 14 − 32%. However, the high Lyα rest-frame equivalent width, low stellar mass and UV luminosity of these LAEs suggest that they should have f esc > 50%. The low LyC escape fraction from this work and other stacking analysis suggest that the LyC leaking galaxies with f esc > 50% at z = 2 − 3 do not follow the relation between the f esc and UV luminosity and Lyα equivalent width (EW) derived from typical galaxies at similar redshift. Therefore, the UV luminosity and Lyα equivalent width (EW) are not the best indicators for the LyC escape fraction.

show abstract

Section: Sample Selectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lyman continuum escape fraction in Ly α emitters at z ≃ 3.1

Bian

Fan

2020

Monthly Notices of the Royal Astronomical Society: Letters

View full text Add to dashboard Cite

show abstract

“…We are aware that different works predict very different escape fractions for Lyα (e.g. Wofford et al 2013;Naidu et al 2017, but we choose to follow the trend observed in Hayes et al (2011). Predicting the spatial and spectral profiles of such emission would require the full calculation from radiative transfer techniques (Verhamme et al 2006(Verhamme et al , 2012Rosdahl et al 2013;Lake et al 2015), which is beyond the scope of this work.…”

Section: Lyα Scattering From Nearby Stellar Continuummentioning

confidence: 99%

Emission from the circumgalactic medium: from cosmological zoom-in simulations to multiwavelength observables

Augustin

Quiret

Milliard

et al. 2019

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We simulate the flux emitted from galaxy halos in order to quantify the brightness of the circumgalactic medium (CGM). We use dedicated zoom-in cosmological simulations with the hydrodynamical Adaptive Mesh Refinement code RAMSES, which are evolved down to z=0 and reach a maximum spatial resolution of 380 h −1 pc and a gas mass resolution up to 1.8×10 5 h −1 M in the densest regions. We compute the expected emission from the gas in the CGM using CLOUDY emissivity models for different lines (e.g. Lyα, CIV, OVI, CVI, OVIII) considering UV background fluorescence, gravitational cooling and continuum emission. In the case of Lyα we additionally consider the scattering of continuum photons. We compare our predictions to current observations and find them to be in good agreement at any redshift after adjusting the Lyα escape fraction. We combine our mock observations with instrument models for FIREBall-2 (UV balloon spectrograph) and HARMONI (visible and NIR IFU on the ELT) to predict CGM observations with either instrument and optimise target selections and observing strategies. Our results show that Lyα emission from the CGM at a redshift of 0.7 will be observable with FIREBall-2 for bright galaxies (NUV∼18 mag), while metal lines like OVI and CIV will remain challenging to detect. HARMONI is found to be well suited to study the CGM at different redshifts with various tracers.

show abstract

“…Motivated in part by almost all confirmed LyC leakers to date (green stars) showing higher ΣSFR than the average at their redshifts, in our Model II we link fesc to ΣSFR (see §4). The green stars represent leakers presented byNaidu et al (2017); de Barros et al (2016); Vanzella et al (2016, 2018); Shapley et al (2016); Bian et al (2017); Matthee et al (2018); Borthakur et al (2014); Leitherer et al (2016); Izotov et al (2016a,b, 2018a,b); Leethochawalit et al (2016); Jones et al (2013);…”

mentioning

confidence: 99%

Rapid Reionization by the Oligarchs: The Case for Massive, UV-bright, Star-forming Galaxies with High Escape Fractions

Naidu

Tacchella

Mason

et al. 2020

ApJ

Self Cite

273

251

View full text Add to dashboard Cite

The protagonists of the last great phase transition of the universe -cosmic reionization -remain elusive. Faint star-forming galaxies are leading candidates because they are found to be numerous and may have significant ionizing photon escape fractions (f esc ). Here we update this picture via an empirical model that successfully predicts latest observations (e.g., the rapid drop in star-formation density (ρ SFR ) at z > 8). We generate an ionizing spectrum for each galaxy in our model and constrain f esc by leveraging latest measurements of the reionization timeline (e.g., Lyα damping of quasars and galaxies at z > 7). Assuming a constant f esc across all sources at z > 6, we find M UV < −13.5 galaxies need f esc =0.21 +0.06 −0.04 to complete reionization. The inferred IGM neutral fraction is [0.9, 0.5, 0.1] at z = [8.2, 6.8, 6.2] ± 0.2, i.e., the bulk of reionization transpires rapidly in 300 Myrs, driven by the z > 8 ρ SFR and favored by high neutral fractions (∼60−90%) measured at z ∼ 7 − 8. Inspired by the emergent sample of Lyman Continuum (LyC) leakers spanning z ∼ 0−6.6 that overwhelmingly displays higher-than-average star-formation surface density (Σ SFR ), we propose a physically motivated model relating f esc to Σ SFR and find f esc ∝ Σ 0.4±0.1 SFR . Since Σ SFR falls by ∼ 2.5 dex between z = 8 and z = 0, our model explains the humble upper limits on f esc at lower redshifts and its required evolution to f esc ∼ 0.2 at z > 6. Within this model, strikingly, <5% of galaxies with M UV < −18 and log(M /M ) > 8 (the 'oligarchs') account for 80% of the reionization budget -a stark departure from the canonical 'democratic' reionization led by copious faint sources. In fact, faint sources (M UV >−16) must be relegated to a limited role in order to ensure high neutral fractions at z = 7 − 8. Shallow faint-end slopes of the UV luminosity function (α UV > −2) and/or f esc distributions skewed toward massive galaxies produce the required late and rapid reionization. We predict LyC leakers like COLA1 (z = 6.6, f esc ∼ 30%, M UV = −21.5) become increasingly common towards z ∼ 6 and that the drivers of reionization do not lie hidden across the faint-end of the luminosity function, but are already known to us.

show abstract

The HDUV Survey: Six Lyman Continuum Emitter Candidates at z ∼ 2 Revealed by HST UV Imaging*

Cited by 34 publications

References 113 publications

Lyman continuum escape fraction in Ly α emitters at z ≃ 3.1

Lyman continuum escape fraction in Ly α emitters at z ≃ 3.1

Emission from the circumgalactic medium: from cosmological zoom-in simulations to multiwavelength observables

Rapid Reionization by the Oligarchs: The Case for Massive, UV-bright, Star-forming Galaxies with High Escape Fractions

Contact Info

Product

Resources

About