The ionizing photon production efficiency of compact<i>z</i>~ 0.3 Lyman continuum leakers and comparison with high-redshift galaxies

Izotov, Y. I.; Verhamme, Anne; Orlitová, Ivana; Thuan, T. X.; Worseck, G.; Гусева, Н. Г.

doi:10.1051/0004-6361/201628943

Cited by 84 publications

(84 citation statements)

References 31 publications

(64 reference statements)

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“…This finding and high efficiency of ionising photon production (Schaerer et al 2016) support the idea that their counterparts at redshifts z ∼ 5 -10 were likely the main sources of the reionisation of the Universe.…”

Section: Introductionsupporting

confidence: 73%

The efficiency of ionizing photon production and the radiation energy balance in compact star-forming galaxies

Izotov

Гусева

Fricke

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We derive apparent and absolute ultraviolet (UV) magnitudes, and luminosities in the infrared (IR) range of a large sample of low-redshift (0 < z < 1) compact starforming galaxies (CSFGs) selected from the Data Release 12 of the Sloan Digital Sky Survey (SDSS). These data are used to constrain the extinction law in the UV for our galaxies and to compare the absorbed radiation in the UV range with the emission in the IR range. We find that the modelled far-and near-UV apparent magnitudes are in good agreement with the observed Galaxy Evolution Explorer (GALEX) magnitudes. It is found that galaxies with low and high equivalent widths EW(Hβ) of the Hβ emission line require different reddening laws with steeper slopes for galaxies with higher EW(Hβ). This implies an important role of the hard ionising radiation in shaping the dust grain size distribution. The IR emission in the range of 8 -1000 µm is determined using existing data obtained by various infrared space telescopes. We find that the radiation energy absorbed in the UV range is nearly equal to the energy emitted in the IR range leaving very little room for hidden star formation in our galaxies. Using extinction-corrected Hβ luminosities and modelled SEDs in the UV range we derive efficiencies of ionising photon production ξ for the entire sample of CSFGs. It is found that ξ in CSFGs with high EW(Hβ) are among the highest known for low-and high-redshift galaxies. If galaxies with similar properties existed at redshifts z = 5 -10, they could be considered as promising candidates for the reionisation of the Universe.

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Section: Introductionsupporting

confidence: 73%

The efficiency of ionizing photon production and the radiation energy balance in compact star-forming galaxies

Izotov

Гусева

Fricke

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…The strong stellar N v λ1240 P-Cygni profile observed in the extreme GP J1608 further indicates an age < 3 Myr ( § 3.2). With young ages, the GPs may be at their peak LyC production (cf., Schaerer et al 2016;Izotov et al 2017a). By ionizing the surrounding nebular gas, this intense radiation may ensure its own escape.…”

Section: Discussionmentioning

confidence: 99%

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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“…It is worth noting that ID14 shows optical oxygen line EWs and ratios similar to the ones of the Lyman continuum emitter discovered at z=3.2, named Ion2 (with confirmed 50 > % escaping ionizing radiation, see de Barros et al 2016;Vanzella et al 2016b) 19 and some local extreme Green Peas sources (also Lyman continuum leakers, Izotov et al 2016;Schaerer et al 2016). A possible link between the large O32 index and the optically thin interstellar medium to ionizing radiation was explored with photo-ionization models by Jaskot & Oey (2013).…”

Section: A Spatially Offset Ultra-faint Lyα Emissionmentioning

confidence: 98%

Magnifying the Early Episodes of Star Formation: Super Star Clusters at Cosmological Distances*

Vanzella

Castellano

Meneghetti

et al. 2017

ApJ

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Magnifying the Early Episodes of Star FormationVanzella, E.; Castellano, M.; Meneghetti, M.; Mercurio, A.; Caminha, G. B.; Cupani, G.; Calura, F.; Christensen, L.; Merlin, E.; Rosati, P. IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document VersionPublisher's PDF, also known as Version of record Publication date: 2017Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Vanzella, E., Castellano, M., Meneghetti, M., Mercurio, A., Caminha, G. B., Cupani, G., ... Tozzi, P. (2017 AbstractWe study the spectrophotometric properties of a highly magnified ( 40 70 m  -) pair of stellar systems identified at z=3.2222 behind the Hubble Frontier Field galaxy cluster MACSJ0416. Five multiple images (out of six) have been spectroscopically confirmed by means of VLT/MUSE and VLT/X-Shooter observations. Each image includes two faint (m 30.6 UV  ), young ( 100  Myr), low-mass ( 10 7 < M  ), low-metallicity (12+Log(O/H);7.7, or 1/10 solar), and compact (30 pc effective radius) stellar systems separated by 300  pc after correcting for lensing amplification. We measured several rest-frame ultraviolet and optical narrow ( 25 v  s kms −1 ) high-ionization lines. These features may be the signature of very hot (T 50,000 > K) stars within dense stellar clusters, whose dynamical mass is likely dominated by the stellar component. Remarkably, the ultraviolet metal lines are not accompanied by Lyα emission (e.g., C IV/Lyα 15 > ), despite the fact that the Lyα line flux is expected to be 150 times brighter (inferred from the Hβ flux). A spatially offset, strongly magnified ( 50 m > ) Lyα emission with a spatial extent 7.6  kpc 2 is instead identified 2kpc away from the system. The origin of such a faint emission could be the result of fluorescent Lyα induced by a transverse leakage of ionizing radiation emerging from the stellar systems and/or may be associated with an underlying and barely detected object (with m 34 UV > de-lensed). This is the first confirmed metal-line emitter at such low-luminosity and redshift without Lyα emission-suggesting that, at least in some cases, a non-uniform covering factor of the neutral gas might hamper the Lyα detection.

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The ionizing photon production efficiency of compactz~ 0.3 Lyman continuum leakers and comparison with high-redshift galaxies

Cited by 84 publications

References 31 publications

The efficiency of ionizing photon production and the radiation energy balance in compact star-forming galaxies

The efficiency of ionizing photon production and the radiation energy balance in compact star-forming galaxies

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

Magnifying the Early Episodes of Star Formation: Super Star Clusters at Cosmological Distances*

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