THE Lyα–LyC CONNECTION: EVIDENCE FOR AN ENHANCED CONTRIBUTION OF UV-FAINT GALAXIES TO COSMIC REIONIZATION

Dijkstra, Mark; Grönke, Max; Venkatesan, Aparna

doi:10.3847/0004-637x/828/2/71

Cited by 158 publications

(196 citation statements)

References 119 publications

(229 reference statements)

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“…Galaxies with low N HI should also have high f Lyα esc (e.g., Yajima et al 2014;Dijkstra et al 2016;Verhamme et al 2017). However, aperture effects may lower f Lyα esc in the new z < 0.12 GPs compared to other GP samples (Jaskot & Oey 2014;Henry et al 2015;Izotov et al 2016b).…”

Section: Introductionmentioning

confidence: 96%

Kinematics and Optical Depth in the Green Peas: Suppressed Superwinds in Candidate LyC Emitters*

Jaskot

Oey

Scarlata

et al. 2017

ApJL

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By clearing neutral gas away from a young starburst, superwinds may regulate the escape of Lyman continuum (LyC) photons from star-forming galaxies. However, models predict that superwinds may not launch in the most extreme, compact starbursts. We explore the role of outflows in generating low optical depths in the Green Peas (GPs), the only known star-forming population with several confirmed and candidate LyC-leaking galaxies. With Hubble Space Telescope UV spectra of 25 low-redshift GPs, including new observations of 13 of the most highly ionized GPs, we compare the kinematics of UV absorption lines with indirect H i optical depth diagnostics: Lyα escape fraction, Lyα peak separation, or low-ionization absorption line equivalent width. The data suggest that high ionization kinematics tracing superwind activity may correlate with low optical depth in some objects. However, the most extreme GPs, including many of the best candidate LyC emitters with weak low-ionization absorption and strong, narrow Lyα profiles, show the lowest velocities. These results are consistent with models for suppressed superwinds, which suggests that outflows may not be the only cause of LyC escape from galaxies.

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Section: Introductionmentioning

confidence: 96%

Kinematics and Optical Depth in the Green Peas: Suppressed Superwinds in Candidate LyC Emitters*

Jaskot

Oey

Scarlata

et al. 2017

ApJL

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“…A shell model requires low neutral gas column density or a high outflow velocity (Verhamme et al 2015). In the case of a multi-phase model (Dijkstra et al 2016), a low-velocity offset translates to a low covering fraction of neutral gas, independent of its neutral column density and outflow velocity. In both models, however, the low-velocity offset is a consequence of the presence of low HI-column density escape routes for Lyα photons, which may also allow ionizing photons to escape (see Verhamme et al 2015Verhamme et al , 2017Dijkstra et al 2016 for more detailed discussions).…”

Section: Resultsmentioning

confidence: 99%

ALMA [C ii] 158 μm Detection of a Redshift 7 Lensed Galaxy behind RX J1347.1−1145*

Bradač

Garcia‐Appadoo

Huang

et al. 2017

ApJL

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107

129

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We present the results of ALMA spectroscopic follow-up of a z=6.766 Lyα emitting galaxy behind the cluster RX J1347.1−1145. We report the detection of [C II] 158 μm line fully consistent with the Lyα redshift and with the peak of the optical emission. Given the magnification of μ=5.0±0.3, the intrinsic (corrected for lensing) luminosity of the, roughly ∼5 times fainter than other detections of z∼7 galaxies. The result indicates that low L [C II] in z∼7 galaxies compared to the local counterparts might be caused by their low metallicities and/or feedback. ) between the Lyα and [C II] line is unusual, and may be indicative of ionizing photons escaping.

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“…In this regard, recent progress has been made in the field of photo-ionization modeling (Jaskot & Oey 2013;Nakajima & Ouchi 2014;Zackrisson et al 2016;Inoue 2011), subsequently confirmed by observations (e.g., de Barros et al 2016;Vanzella et al 2016b;Verhamme et al 2016). In particular, line ratios in the rest-frame optical band like the O32 index ([Oiii]λ5007/[Oii]λ3727) and specific properties of the Lyα profile (Behrens et al 2014;Verhamme et al 2015;Dijkstra et al 2016) can provide valuable indirect probes of the physical state of the interstellar medium and of the column density of neutral gas (e.g., density-bounded or ionization-bounded), as well as the connection with the ultraviolet spectral slope, the Balmer emission lines and the Lyman continuum leakage (Zackrisson et al 2013(Zackrisson et al , 2016.…”

Section: Dynamical Mass Of Id11mentioning

confidence: 99%

Paving the way for the JWST: witnessing globular cluster formation at z > 3

Vanzella¹,

Calura²,

Meneghetti³

et al. 2017

Monthly Notices of the Royal Astronomical Society

180

215

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We report on five compact, extremely young (< 10 Myr) and blue (β U V < −2.5, F λ = λ β ) objects observed with VLT/MUSE at redshift 3.1169, 3.235, in addition to three objects at z = 6.145. These sources are magnified by the Hubble Frontier Field galaxy clusters MACS J0416 and AS1063. Their de-lensed half light radii (R e ) are between 16 to 140 pc, the stellar masses are 1 − 20 × 10 6 M , the magnitudes are m U V = 28.8 − 31.4 (−17 < M U V < −15) and specific star formation rates can be as large as ∼ 800 Gyr −1 . Multiple images of these systems are widely separated in the sky (up to 50 ) and individually magnified by factors 3-40. Remarkably, the inferred physical properties of two objects are similar to those expected in some globular cluster formation scenarios, representing the best candidate proto-globular clusters (proto-GC) discovered so far. Rest-frame optical high dispersion spectroscopy of one of them at z = 3.1169 yields a velocity dispersion σ v 20 km s −1 , implying a dynamical mass dominated by the stellar mass. Another object at z = 6.145, with de-lensed31.4), shows a stellar mass and a star-formation rate surface density consistent with the values expected from popular GC formation scenarios. An additional star-forming region at z = 6.145, with de-lensed m U V 32, a stellar mass of 0.5 ×10 6 M and a star formation rate of 0.06 M yr −1 is also identified. These objects currently represent the faintest spectroscopically confirmed star-forming systems at z > 3, elusive even in the deepest blank fields. We discuss how proto-GCs might contribute to the ionization budget of the universe and augment Lyα visibility during reionization. This work underlines the crucial role of JWST in characterizing the restframe optical and near-infrared properties of such low-luminosity high−z objects.

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THE Lyα–LyC CONNECTION: EVIDENCE FOR AN ENHANCED CONTRIBUTION OF UV-FAINT GALAXIES TO COSMIC REIONIZATION

Cited by 158 publications

References 119 publications

Kinematics and Optical Depth in the Green Peas: Suppressed Superwinds in Candidate LyC Emitters*

Kinematics and Optical Depth in the Green Peas: Suppressed Superwinds in Candidate LyC Emitters*

ALMA [C ii] 158 μm Detection of a Redshift 7 Lensed Galaxy behind RX J1347.1−1145*

Paving the way for the JWST: witnessing globular cluster formation at z > 3

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