skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Elevated ionizing photon production efficiency in faint high-equivalent-width Lyman-α emitters

Abstract

ABSTRACT While low-luminosity galaxies dominate number counts at all redshifts, their contribution to cosmic reionization is poorly understood due to a lack of knowledge of their physical properties. We isolate a sample of 35 z ≈ 4–5 continuum-faint Lyman-α emitters from deep VLT/MUSE spectroscopy and directly measure their H α emission using stacked Spitzer/IRAC Ch. 1 photometry. Based on Hubble Space Telescope imaging, we determine that the average UV continuum magnitude is fainter than −16 (≈ 0.01 L⋆), implying a median Lyman-α equivalent width of 259 Å. By combining the H α measurement with the UV magnitude, we determine the ionizing photon production efficiency, ξion, a first for such faint galaxies. The measurement of log10 (ξion [Hz erg−1]) = 26.28 ($$^{+0.28}_{-0.40}$$) is in excess of literature measurements of both continuum- and emission line-selected samples, implying a more efficient production of ionizing photons in these lower luminosity, Lyman-α-selected systems. We conclude that this elevated efficiency can be explained by stellar populations with metallicities between 4 × 10−4 and 0.008, with light-weighted ages less than 3 Myr.

Authors:
ORCiD logo [1];  [2];  [1]; ORCiD logo [3];  [4]; ORCiD logo [1];  [5];  [6];  [1];  [1]; ORCiD logo [3];  [1]; ORCiD logo [7];  [8];  [9];  [10];  [1];  [2];  [6]
  1. Leiden Observatory, Leiden University, PO Box 9513, NL-2300 RA, Leiden, the Netherlands
  2. Univ Lyon, Univ Lyon 1, CNRS, Centre de Recherche Astrophysique de Lyon UMR5574, F-69230, Saint-Genis-Laval, France
  3. ETH Zürich, Department of Physics, Wolfgang-Pauli-Str. 27, CH-8093 Zürich, Switzerland
  4. Leiden Observatory, Leiden University, PO Box 9513, NL-2300 RA, Leiden, the Netherlands, Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, PT4150-762 Porto, Portugal
  5. Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
  6. Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam, Germany
  7. Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan
  8. Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
  9. Observatoire de Genève, Université de Genève, 51 Ch. des Maillettes, CH-1290 Versoix, Switzerland
  10. Department of Astronomy, University of Michigan, 1085 South University Ave., Ann Arbor, MI 48109, USA
Publication Date:
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Fuel Cell Technologies Office (EE-3F)
OSTI Identifier:
1605941
Resource Type:
Published Article
Journal Name:
Monthly Notices of the Royal Astronomical Society
Additional Journal Information:
[Journal Name: Monthly Notices of the Royal Astronomical Society Journal Volume: 493 Journal Issue: 4]; Journal ID: ISSN 0035-8711
Publisher:
Oxford University Press
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Maseda, Michael V., Bacon, Roland, Lam, Daniel, Matthee, Jorryt, Brinchmann, Jarle, Schaye, Joop, Labbe, Ivo, Schmidt, Kasper B., Boogaard, Leindert, Bouwens, Rychard, Cantalupo, Sebastiano, Franx, Marijn, Hashimoto, Takuya, Inami, Hanae, Kusakabe, Haruka, Mahler, Guillaume, Nanayakkara, Themiya, Richard, Johan, and Wisotzki, Lutz. Elevated ionizing photon production efficiency in faint high-equivalent-width Lyman-α emitters. United Kingdom: N. p., 2020. Web. doi:10.1093/mnras/staa622.
Maseda, Michael V., Bacon, Roland, Lam, Daniel, Matthee, Jorryt, Brinchmann, Jarle, Schaye, Joop, Labbe, Ivo, Schmidt, Kasper B., Boogaard, Leindert, Bouwens, Rychard, Cantalupo, Sebastiano, Franx, Marijn, Hashimoto, Takuya, Inami, Hanae, Kusakabe, Haruka, Mahler, Guillaume, Nanayakkara, Themiya, Richard, Johan, & Wisotzki, Lutz. Elevated ionizing photon production efficiency in faint high-equivalent-width Lyman-α emitters. United Kingdom. doi:10.1093/mnras/staa622.
Maseda, Michael V., Bacon, Roland, Lam, Daniel, Matthee, Jorryt, Brinchmann, Jarle, Schaye, Joop, Labbe, Ivo, Schmidt, Kasper B., Boogaard, Leindert, Bouwens, Rychard, Cantalupo, Sebastiano, Franx, Marijn, Hashimoto, Takuya, Inami, Hanae, Kusakabe, Haruka, Mahler, Guillaume, Nanayakkara, Themiya, Richard, Johan, and Wisotzki, Lutz. Wed . "Elevated ionizing photon production efficiency in faint high-equivalent-width Lyman-α emitters". United Kingdom. doi:10.1093/mnras/staa622.
@article{osti_1605941,
title = {Elevated ionizing photon production efficiency in faint high-equivalent-width Lyman-α emitters},
author = {Maseda, Michael V. and Bacon, Roland and Lam, Daniel and Matthee, Jorryt and Brinchmann, Jarle and Schaye, Joop and Labbe, Ivo and Schmidt, Kasper B. and Boogaard, Leindert and Bouwens, Rychard and Cantalupo, Sebastiano and Franx, Marijn and Hashimoto, Takuya and Inami, Hanae and Kusakabe, Haruka and Mahler, Guillaume and Nanayakkara, Themiya and Richard, Johan and Wisotzki, Lutz},
abstractNote = {ABSTRACT While low-luminosity galaxies dominate number counts at all redshifts, their contribution to cosmic reionization is poorly understood due to a lack of knowledge of their physical properties. We isolate a sample of 35 z ≈ 4–5 continuum-faint Lyman-α emitters from deep VLT/MUSE spectroscopy and directly measure their H α emission using stacked Spitzer/IRAC Ch. 1 photometry. Based on Hubble Space Telescope imaging, we determine that the average UV continuum magnitude is fainter than −16 (≈ 0.01 L⋆), implying a median Lyman-α equivalent width of 259 Å. By combining the H α measurement with the UV magnitude, we determine the ionizing photon production efficiency, ξion, a first for such faint galaxies. The measurement of log10 (ξion [Hz erg−1]) = 26.28 ($^{+0.28}_{-0.40}$) is in excess of literature measurements of both continuum- and emission line-selected samples, implying a more efficient production of ionizing photons in these lower luminosity, Lyman-α-selected systems. We conclude that this elevated efficiency can be explained by stellar populations with metallicities between 4 × 10−4 and 0.008, with light-weighted ages less than 3 Myr.},
doi = {10.1093/mnras/staa622},
journal = {Monthly Notices of the Royal Astronomical Society},
number = [4],
volume = [493],
place = {United Kingdom},
year = {2020},
month = {3}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1093/mnras/staa622

Save / Share:

Works referenced in this record:

EXTREME EMISSION-LINE GALAXIES IN CANDELS: BROADBAND-SELECTED, STARBURSTING DWARF GALAXIES AT z > 1
journal, November 2011


Ly α EMISSION FROM GREEN PEAS: THE ROLE OF CIRCUMGALACTIC GAS DENSITY, COVERING, AND KINEMATICS
journal, August 2015

  • Henry, Alaina; Scarlata, Claudia; Martin, Crystal L.
  • The Astrophysical Journal, Vol. 809, Issue 1
  • DOI: 10.1088/0004-637X/809/1/19

Large Equivalent Width L[CLC]y[/CLC]α line Emission at [FORMULA][F]z=4.5[/F][/FORMULA]: Young Galaxies in a Young Universe?
journal, February 2002

  • Malhotra, Sangeeta; Rhoads, James E.
  • The Astrophysical Journal, Vol. 565, Issue 2
  • DOI: 10.1086/338980

THE REST-FRAME UV-TO-OPTICAL COLORS AND SPECTRAL ENERGY DISTRIBUTIONS OF z ∼ 4-7 GALAXIES
journal, August 2012


SILVERRUSH. V. Census of Ly α , [O iii] λ 5007, H α , and [C ii] 158 μ m Line Emission with ∼1000 LAEs at z = 4.9–7.0 Revealed with Subaru/HSC
journal, May 2018

  • Harikane, Yuichi; Ouchi, Masami; Shibuya, Takatoshi
  • The Astrophysical Journal, Vol. 859, Issue 2
  • DOI: 10.3847/1538-4357/aabd80

The Major Sources of the Cosmic Reionizing Background at z 6
journal, December 2003

  • Yan, Haojing; Windhorst, Rogier A.
  • The Astrophysical Journal, Vol. 600, Issue 1
  • DOI: 10.1086/381573

Ultradeep irac Imaging over the hudf and Goods-South: Survey Design and Imaging data Release
journal, November 2015

  • Labbé, I.; Oesch, P. A.; Illingworth, G. D.
  • The Astrophysical Journal Supplement Series, Vol. 221, Issue 2
  • DOI: 10.1088/0067-0049/221/2/23

Predicting dust extinction from the stellar mass of a galaxy: Dust extinction and stellar mass
journal, September 2010


New Insights on Ly α and Lyman Continuum Radiative Transfer in the Greenest Peas
journal, November 2019


Understanding Galaxy Evolution Through Emission Lines
journal, August 2019


Gusty, gaseous flows of FIRE: galactic winds in cosmological simulations with explicit stellar feedback
journal, October 2015

  • Muratov, Alexander L.; Kereš, Dušan; Faucher-Giguère, Claude-André
  • Monthly Notices of the Royal Astronomical Society, Vol. 454, Issue 3
  • DOI: 10.1093/mnras/stv2126

The MUSE Hubble Ultra Deep Field Survey : X. Ly
journal, November 2017


THE HST EXTREME DEEP FIELD (XDF): COMBINING ALL ACS AND WFC3/IR DATA ON THE HUDF REGION INTO THE DEEPEST FIELD EVER
journal, October 2013

  • Illingworth, G. D.; Magee, D.; Oesch, P. A.
  • The Astrophysical Journal Supplement Series, Vol. 209, Issue 1
  • DOI: 10.1088/0067-0049/209/1/6

CONFIRMATION OF SMALL DYNAMICAL AND STELLAR MASSES FOR EXTREME EMISSION LINE GALAXIES AT z ∼ 2
journal, November 2013

  • Maseda, Michael V.; van der Wel, Arjen; da Cunha, Elisabete
  • The Astrophysical Journal, Vol. 778, Issue 1
  • DOI: 10.1088/2041-8205/778/1/L22

Dust Absorption and the Ultraviolet Luminosity Density at z  ≈ 3 as Calibrated by Local Starburst Galaxies
journal, August 1999

  • Meurer, Gerhardt R.; Heckman, Timothy M.; Calzetti, Daniela
  • The Astrophysical Journal, Vol. 521, Issue 1
  • DOI: 10.1086/307523

An updated analytic model for attenuation by the intergalactic medium
journal, June 2014

  • Inoue, Akio K.; Shimizu, Ikkoh; Iwata, Ikuru
  • Monthly Notices of the Royal Astronomical Society, Vol. 442, Issue 2
  • DOI: 10.1093/mnras/stu936

Conditions for Reionizing the Universe with a Low Galaxy Ionizing Photon Escape Fraction
journal, July 2019

  • Finkelstein, Steven L.; D’Aloisio, Anson; Paardekooper, Jan-Pieter
  • The Astrophysical Journal, Vol. 879, Issue 1
  • DOI: 10.3847/1538-4357/ab1ea8

HDUV: The Hubble Deep UV Legacy Survey
journal, July 2018

  • Oesch, P. A.; Montes, M.; Reddy, N.
  • The Astrophysical Journal Supplement Series, Vol. 237, Issue 1
  • DOI: 10.3847/1538-4365/aacb30

The MUSE second-generation VLT instrument
conference, July 2010

  • Bacon, R.; Accardo, M.; Adjali, L.
  • SPIE Astronomical Telescopes + Instrumentation, SPIE Proceedings
  • DOI: 10.1117/12.856027

Lyα emitters with very large Lyα equivalent widths, EW 0 (Lyα) ≃ 200–400 Å, at z ∼ 2
journal, November 2016

  • Hashimoto, Takuya; Ouchi, Masami; Shimasaku, Kazuhiro
  • Monthly Notices of the Royal Astronomical Society, Vol. 465, Issue 2
  • DOI: 10.1093/mnras/stw2834

MUSE Spectroscopic Identifications of Ultra-faint Emission Line Galaxies with M UV ∼ −15
journal, September 2018

  • Maseda, Michael V.; Bacon, Roland; Franx, Marijn
  • The Astrophysical Journal, Vol. 865, Issue 1
  • DOI: 10.3847/2041-8213/aade4b

Spectroscopic detection of C iv λ1548 in a galaxy at z  = 7.045: implications for the ionizing spectra of reionization-era galaxies
journal, October 2015

  • Stark, Daniel P.; Walth, Gregory; Charlot, Stéphane
  • Monthly Notices of the Royal Astronomical Society, Vol. 454, Issue 2
  • DOI: 10.1093/mnras/stv1907

Can the intergalactic medium cause a rapid drop in Lyα emission at z > 6?
journal, November 2014

  • Mesinger, Andrei; Aykutalp, Aycin; Vanzella, Eros
  • Monthly Notices of the Royal Astronomical Society, Vol. 446, Issue 1
  • DOI: 10.1093/mnras/stu2089

THE SPECTROSCOPIC PROPERTIES OF Ly α -EMITTERS AT z ∼ 2.7: ESCAPING GAS AND PHOTONS FROM FAINT GALAXIES
journal, August 2015

  • Trainor, Ryan F.; Steidel, Charles C.; Strom, Allison L.
  • The Astrophysical Journal, Vol. 809, Issue 1
  • DOI: 10.1088/0004-637X/809/1/89

Lyα and C iii] emission in z = 7–9 Galaxies: accelerated reionization around luminous star-forming systems?
journal, September 2016

  • Stark, Daniel P.; Ellis, Richard S.; Charlot, Stéphane
  • Monthly Notices of the Royal Astronomical Society, Vol. 464, Issue 1
  • DOI: 10.1093/mnras/stw2233

The Luminosity Function and Stellar Evolution.
journal, January 1955

  • Salpeter, Edwin E.
  • The Astrophysical Journal, Vol. 121
  • DOI: 10.1086/145971

REIONIZATION AFTER PLANCK : THE DERIVED GROWTH OF THE COSMIC IONIZING EMISSIVITY NOW MATCHES THE GROWTH OF THE GALAXY UV LUMINOSITY DENSITY
journal, September 2015


z ∼ 4 Hα EMITTERS IN THE GREAT OBSERVATORIES ORIGINS DEEP SURVEY: TRACING THE DOMINANT MODE FOR GROWTH OF GALAXIES
journal, August 2011


The MUSE Hubble Ultra Deep Field Survey : I. Survey description, data reduction, and source detection⋆
journal, November 2017


Exploring He II  λ 1640 emission line properties at z ∼2−4
journal, April 2019


Powering reionization: assessing the galaxy ionizing photon budget at z < 10
journal, June 2015

  • Duncan, Kenneth; Conselice, Christopher J.
  • Monthly Notices of the Royal Astronomical Society, Vol. 451, Issue 2
  • DOI: 10.1093/mnras/stv1049

Consequences of bursty star formation on galaxy observables at high redshifts
journal, May 2015

  • Domínguez, Alberto; Siana, Brian; Brooks, Alyson M.
  • Monthly Notices of the Royal Astronomical Society, Vol. 451, Issue 1
  • DOI: 10.1093/mnras/stv1001

Spectroscopic properties of luminous Ly α emitters at z ≈ 6–7 and comparison to the Lyman-break population
journal, August 2017

  • Matthee, Jorryt; Sobral, David; Darvish, Behnam
  • Monthly Notices of the Royal Astronomical Society, Vol. 472, Issue 1
  • DOI: 10.1093/mnras/stx2061

MMT/MMIRS spectroscopy of z = 1.3 - 2.4 extreme [O iii] emitters: implications for galaxies in the reionization era
journal, August 2019

  • Tang, Mengtao; Stark, Daniel P.; Chevallard, Jacopo
  • Monthly Notices of the Royal Astronomical Society, Vol. 489, Issue 2
  • DOI: 10.1093/mnras/stz2236

Physical properties and H-ionizing-photon production rates of extreme nearby star-forming regions
journal, June 2018

  • Chevallard, Jacopo; Charlot, Stéphane; Senchyna, Peter
  • Monthly Notices of the Royal Astronomical Society, Vol. 479, Issue 3
  • DOI: 10.1093/mnras/sty1461

CALIBRATING EXTINCTION-FREE STAR FORMATION RATE DIAGNOSTICS WITH 33 GHz FREE-FREE EMISSION IN NGC 6946
journal, August 2011


Predicted UV properties of very metal-poor starburst galaxies
journal, November 2010


UV LUMINOSITY FUNCTIONS AT REDSHIFTS z ∼ 4 TO z ∼ 10: 10,000 GALAXIES FROM HST LEGACY FIELDS
journal, April 2015


Candels: the Contribution of the Observed Galaxy Population to Cosmic Reionization
journal, October 2012

  • Finkelstein, Steven L.; Papovich, Casey; Ryan, Russell E.
  • The Astrophysical Journal, Vol. 758, Issue 2
  • DOI: 10.1088/0004-637X/758/2/93

The role of galaxies and AGNs in reionizing the IGM – II. Metal-tracing the faint sources of reionization at 5 ≲ z ≲ 6
journal, November 2018

  • Meyer, Romain A.; Bosman, Sarah E. I.; Kakiichi, Koki
  • Monthly Notices of the Royal Astronomical Society, Vol. 483, Issue 1
  • DOI: 10.1093/mnras/sty2954

The extreme faint end of the UV luminosity function at z ∼ 6 through gravitational telescopes: a comprehensive assessment of strong lensing uncertainties
journal, July 2018

  • Atek, Hakim; Richard, Johan; Kneib, Jean-Paul
  • Monthly Notices of the Royal Astronomical Society, Vol. 479, Issue 4
  • DOI: 10.1093/mnras/sty1820

Subkiloparsec Imaging of Ly α Emission in a Low-mass, Highly Ionized, Gravitationally Lensed Galaxy at z = 1.84
journal, October 2019

  • Erb, Dawn K.; Berg, Danielle A.; Auger, Matthew W.
  • The Astrophysical Journal, Vol. 884, Issue 1
  • DOI: 10.3847/1538-4357/ab3daf

Ly α -Lyman continuum connection in 3.5 ≤ z ≤ 4.3 star-forming galaxies from the VUDS survey
journal, June 2018


The physics of Lyman α escape from high-redshift galaxies
journal, December 2018

  • Smith, Aaron; Ma, Xiangcheng; Bromm, Volker
  • Monthly Notices of the Royal Astronomical Society, Vol. 484, Issue 1
  • DOI: 10.1093/mnras/sty3483

The escape of Lyman-alpha radiation from a multiphase interstellar medium
journal, March 1991

  • Neufeld, David A.
  • The Astrophysical Journal, Vol. 370
  • DOI: 10.1086/185983

STELLAR POPULATIONS OF Lyα EMITTERS AT z ∼ 6-7: CONSTRAINTS ON THE ESCAPE FRACTION OF IONIZING PHOTONS FROM GALAXY BUILDING BLOCKS
journal, November 2010


THE Ly α –LyC CONNECTION: EVIDENCE FOR AN ENHANCED CONTRIBUTION OF UV-FAINT GALAXIES TO COSMIC REIONIZATION
journal, September 2016


THE REST-FRAME OPTICAL SPECTROSCOPIC PROPERTIES OF LY α -EMITTERS AT z ∼ 2.5: THE PHYSICAL ORIGINS OF STRONG LY α EMISSION
journal, November 2016

  • Trainor, Ryan F.; Strom, Allison L.; Steidel, Charles C.
  • The Astrophysical Journal, Vol. 832, Issue 2
  • DOI: 10.3847/0004-637X/832/2/171

The MUSE Hubble Ultra Deep Field Survey : VI. The faint-end of the Ly
journal, November 2017


The Baryon Cycle of Dwarf Galaxies: Dark, Bursty, Gas-Rich Polluters
journal, August 2014


THE NATURE OF EXTREME EMISSION LINE GALAXIES AT z = 1-2: KINEMATICS AND METALLICITIES FROM NEAR-INFRARED SPECTROSCOPY
journal, July 2014

  • Maseda, Michael V.; van der Wel, Arjen; Rix, Hans-Walter
  • The Astrophysical Journal, Vol. 791, Issue 1
  • DOI: 10.1088/0004-637X/791/1/17

The z ∼ 6 Luminosity Function Fainter than −15 mag from the Hubble Frontier Fields: The Impact of Magnification Uncertainties
journal, July 2017

  • Bouwens, R. J.; Oesch, P. A.; Illingworth, G. D.
  • The Astrophysical Journal, Vol. 843, Issue 2
  • DOI: 10.3847/1538-4357/aa70a4

The MOSDEF Survey: Direct Observational Constraints on the Ionizing Photon Production Efficiency, ξ ion , at z ∼ 2
journal, March 2018

  • Shivaei, Irene; Reddy, Naveen A.; Siana, Brian
  • The Astrophysical Journal, Vol. 855, Issue 1
  • DOI: 10.3847/1538-4357/aaad62

Stellar population effects on the inferred photon density at reionization
journal, December 2015

  • Stanway, Elizabeth R.; Eldridge, J. J.; Becker, George D.
  • Monthly Notices of the Royal Astronomical Society, Vol. 456, Issue 1
  • DOI: 10.1093/mnras/stv2661

Modelling the nebular emission from primeval to present-day star-forming galaxies
journal, July 2016

  • Gutkin, Julia; Charlot, Stéphane; Bruzual, Gustavo
  • Monthly Notices of the Royal Astronomical Society, Vol. 462, Issue 2
  • DOI: 10.1093/mnras/stw1716

An 800-million-solar-mass black hole in a significantly neutral Universe at a redshift of 7.5
journal, December 2017

  • Bañados, Eduardo; Venemans, Bram P.; Mazzucchelli, Chiara
  • Nature, Vol. 553, Issue 7689
  • DOI: 10.1038/nature25180

New Constraints on Cosmic Reionization from the 2012 Hubble Ultra deep Field Campaign
journal, April 2013

  • Robertson, Brant E.; Furlanetto, Steven R.; Schneider, Evan
  • The Astrophysical Journal, Vol. 768, Issue 1
  • DOI: 10.1088/0004-637X/768/1/71

The mean H α EW and Lyman-continuum photon production efficiency for faint z ≈ 4−5 galaxies
journal, July 2019


The production and escape of Lyman-Continuum radiation from star-forming galaxies at z ∼ 2 and their redshift evolution
journal, November 2016

  • Matthee, Jorryt; Sobral, David; Best, Philip
  • Monthly Notices of the Royal Astronomical Society, Vol. 465, Issue 3
  • DOI: 10.1093/mnras/stw2973

Absolute Spectral Energy Distributions for White Dwarfs
journal, February 1974

  • Oke, J. B.
  • The Astrophysical Journal Supplement Series, Vol. 27
  • DOI: 10.1086/190287

Nebular emission from star-forming galaxies
journal, May 2001


Mean Hα+[N ii]+[S ii] EW inferred for star-forming galaxies at z  ∼ 5.1–5.4 using high-quality Spitzer /IRAC photometry
journal, June 2016

  • Rasappu, N.; Smit, R.; Labbé, I.
  • Monthly Notices of the Royal Astronomical Society, Vol. 461, Issue 4
  • DOI: 10.1093/mnras/stw1484