The Low-redshift Lyman Continuum Survey. I. New, Diverse Local Lyman Continuum Emitters

Flury, Sophia R.; Jaskot, Anne; Ferguson, Harry; Worseck, G.; Makan, Kirill; Chisholm, John; Saldana-Lopez, Alberto; Schaerer, D.; McCandless, Stephan; Wang, Bingjie; Ford, N. M.; Heckman, Timothy M.; Ji, Zhiyuan; Giavalisco, Mauro; Amorín, R.; Atek, Hakim; Blaizot, Jérémy; Borthakur, Sanchayeeta; Carr, Charles W.; Castellano, M.; Cristiani, S.; Barros, S. de; Dickinson, Mark; Finkelstein, Steven L.; Fleming, Brian; Fontanot, Fabio; Garel, Thibault; Grazian, A.; Hayes, Matthew; Henry, Alaina; Mauerhofer, Valentin; Micheva, Genoveva; Oey, M. S.; Östlin, Göran; Papovich, Casey; Pentericci, L.; Ravindranath, Swara; Rosdahl, Joakim; Rutkowski, Michael; Santini, P.; Scarlata, Claudia; Teplitz, Harry I.; Thuan, T. X.; Trebitsch, Maxime; Vanzella, E.; Verhamme, Anne; Xu, Xinfeng

doi:10.3847/1538-4365/ac5331

Cited by 92 publications

(133 citation statements)

References 116 publications

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“…This program obtained COS G140L and G160M observations that probed the LyC and Lyα regions, respectively. One of the eight galaxies (J1246+4449) overlaps with the Low-redshift Lyman Continuum Survey (LzLCS, HST GO: 15626; PI: Jaskot ;Flury et al 2022a), so we use the archival LyC observations for this object (but we still acquired new G160M observations). The details of observations are listed in Table 1.…”

Section: Cos Observations and Reductionmentioning

confidence: 99%

“…To get robust estimates of the LyC flux from the HST/COS G140L spectra, we follow the reduction methods in previous publications (Wang et al 2019;Flury et al 2022a). We use the standard CALCOS pipeline (v3.3.9) and further estimate the dark current and scattered geocoronal Lyα background adopting the custom software FaintCOS (Makan et al 2021).…”

Section: Cos Observations and Reductionmentioning

confidence: 99%

“…In the literature, flux in the Lyman continuum (F(LyC)) is usually measured as the average flux over a window (∼20 Å in the rest frame) close to and shortward of the Lyman limit (e.g., Izotov et al 2021;Flury et al 2022aFlury et al , 2022b. Due to the redshift range of our galaxies, a few of the LyC regions are close to geocoronal Lyα emission lines.…”

Section: The Observed Lyc Fluxmentioning

confidence: 99%

“…We take the same criteria to define an LyC detection as in LzLCS (Flury et al 2022a), i.e., galaxies with LyC flux detected at the >2σ level. In this case, four out of our eight galaxies are classified as detections.…”

Section: The Observed Lyc Fluxmentioning

confidence: 99%

“…Thus, observations at lower redshifts must develop indirect indicators for f esc LyC , which can then be applied to EOR galaxies. During the past decade, considerable efforts have been made toward measuring f esc LyC at low redshifts, mainly adopting observations from the Far Ultraviolet Spectroscopic Explorer (FUSE; e.g., Heckman et al 2001;Bergvall et al 2006;Leitet et al 2013;Borthakur et al 2014) and Hubble Space Telescope/Cosmic Origins Spectrograph (HST/COS; e.g., Izotov et al 2016aIzotov et al , 2016bLeitherer et al 2016;Puschnig et al 2017;Izotov et al 2018aIzotov et al , 2018bWang et al 2019;Izotov et al 2021;Flury et al 2022aFlury et al , 2022b. Various indirect indicators of f esc LyC have also been proposed (see a summary in Flury et al 2022b).…”

Section: Introductionmentioning

confidence: 99%

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Tracing Lyα and LyC Escape in Galaxies with Mg ii Emission

Henry

Heckman

et al. 2022

ApJ

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Star-forming galaxies are considered the likeliest source of the H i ionizing Lyman continuum (LyC) photons that reionized the intergalactic medium at high redshifts. However, above z ≳ 6, the neutral intergalactic medium prevents direct observations of LyC. Therefore, recent years have seen the development of indirect indicators for LyC that can be calibrated at lower redshifts and applied in the epoch of reionization. Emission from the Mg ii λλ2796, 2803 doublet has been proposed as a promising LyC proxy. In this paper, we present new Hubble Space Telescope/Cosmic Origins Spectrograph observations for eight LyC emitter candidates, selected to have strong Mg ii emission lines. We securely detect LyC emission in 50% (4/8) of the galaxies with 2σ significance. This high detection rate suggests that strong Mg ii emitters might be more likely to leak LyC than similar galaxies without strong Mg ii. Using photoionization models, we constrain the escape fraction of Mg ii as ∼15%–60%. We confirm that the escape fraction of Mg ii correlates tightly with that of Lyα, which we interpret as an indication that the escape fraction of both species is controlled by resonant scattering in the same low column density gas. Furthermore, we show that the combination of the Mg ii emission and dust attenuation can be used to estimate the escape fraction of LyC statistically. These findings confirm that Mg ii emission can be adopted to estimate the escape fraction of Lyα and LyC in local star-forming galaxies and may serve as a useful indirect indicator at the epoch of reionization.

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Section: Cos Observations and Reductionmentioning

confidence: 99%

Section: Cos Observations and Reductionmentioning

confidence: 99%

Section: The Observed Lyc Fluxmentioning

confidence: 99%

Section: The Observed Lyc Fluxmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Tracing Lyα and LyC Escape in Galaxies with Mg ii Emission

Henry

Heckman

et al. 2022

ApJ

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Mapping the influence of massive stars

Fleming

2022

Nat Astron

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Identification and properties of intense star-forming galaxies at redshifts z > 10

et al. 2023

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Surveys with James Webb Space Telescope (JWST) have discovered candidate galaxies in the first 400 Myr of cosmic time 1-5 . The properties of these distant galaxies provide initial conditions for understanding early galaxy formation and cosmic reionisation 6 . Preliminary indications have suggested these candidate galaxies may be more massive and abundant than previously thought 1,7-9 . However, without spectroscopic confirmation of their distances to constrain their intrinsic brightnesses, their inferred properties remain uncertain. Here we report on four galaxies located in the JWST Advanced Deep Extragalactic Survey (JADES) Near-Infrared Camera (NIRCam) imaging with photometric redshifts 𝒛 ∼ 𝟏𝟎 − 𝟏𝟑 subsequently confirmed by JADES JWST Near-Infrared Spectrograph (NIRSpec) observations 10 . These galaxies include the first redshift 𝒛 > 𝟏𝟐 systems both discovered and spectroscopically confirmed by JWST. Using stellar population modelling, we find the galaxies typically contain a hundred million solar masses in stars, in stellar populations that are less than one hundred million years old. The moderate star formation rates and compact sizes suggest elevated star formation rate surface densities, a key indicator of their formation pathways. Taken together, these measurements show that the first galaxies contributing to cosmic reionisation formed rapidly and with intense internal radiation fields.

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The Low-redshift Lyman Continuum Survey. I. New, Diverse Local Lyman Continuum Emitters

Cited by 92 publications

References 116 publications

Tracing Lyα and LyC Escape in Galaxies with Mg ii Emission

Tracing Lyα and LyC Escape in Galaxies with Mg ii Emission

Mapping the influence of massive stars

Identification and properties of intense star-forming galaxies at redshifts z > 10

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