The VANDELS survey: a strong correlation between Ly α equivalent width and stellar metallicity at 3 ≤ z ≤ 5

F. Cullen; R. J. McLure; J. S. Dunlop; A. C. Carnall; D. J. McLeod; A. E. Shapley; R. Amorín; M. Bolzonella; M. Castellano; A. Cimatti; M. Cirasuolo; O. Cucciati; A. Fontana; F. Fontanot; B. Garilli; L. Guaita; M. J. Jarvis; L. Pentericci; L. Pozzetti; M. Talia; G. Zamorani; A. Calabrò; G. Cresci; J. P.U. Fynbo; N. P. Hathi; M. Giavalisco; A. Koekemoer; F. Mannucci; A. Saxena

doi:10.1093/MNRAS/STAA1260

The VANDELS survey: a strong correlation between Ly α equivalent width and stellar metallicity at 3 ≤ z ≤ 5

F. Cullen, R. J. McLure, J. S. Dunlop, A. C. Carnall, D. J. McLeod, A. E. Shapley, R. Amorín, M. Bolzonella, M. Castellano, A. Cimatti, M. Cirasuolo, O. Cucciati, A. Fontana, F. Fontanot, B. Garilli, L. Guaita, M. J. Jarvis, L. Pentericci, L. Pozzetti, M. TaliaG. Zamorani, A. Calabrò, G. Cresci, J. P.U. Fynbo, N. P. Hathi, M. Giavalisco, A. Koekemoer, F. Mannucci, A. Saxena

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Abstract

We present the results of a new study investigating the relationship between observed Ly α equivalent width (W_λ(Ly α)) and the metallicity of the ionizing stellar population (Z_★) for a sample of 768 star-forming galaxies at 3 ≤ z ≤ 5 drawn from the VANDELS survey. Dividing our sample into quartiles of rest-frame W_λ(Ly α) across the range −58 Å ≾ W_λ(Ly α) ≾ 110 Å, we determine Z_★ from full spectral fitting of composite far-ultraviolet spectra and find a clear anticorrelation between W_λ(Ly α) and Z_★. Our results indicate that Z_★ decreases by a factor ≳ 3 between the lowest W_λ(Ly α) quartile (≺W_λ(Ly α)≻ = −18 Å) and the highest W_λ(Ly α) quartile (≺W_λ(Ly α)≻ = 24 Å). Similarly, galaxies typically defined as Lyman alpha emitters (LAEs; W_λ(Ly α) > 20 Å) are, on average, metal poor with respect to the non-LAE galaxy population (W_λ(Ly α) ≤ 20 Å) with Z_★_non-LAE ≳ 2 × Z_★LAE. Finally, based on the best-fitting stellar models, we estimate that the increasing strength of the stellar ionizing spectrum towards lower Z_★ is responsible for ≈15−25 per cent of the observed variation in W_λ(Ly α) across our sample, with the remaining contribution (≈75−85 per cent) being due to a decrease in the H I/dust covering fractions in low- Z_★ galaxies.

Original language	English
Pages (from-to)	1501-1510
Number of pages	10
Journal	Monthly Notices of the Royal Astronomical Society
Volume	495
Issue number	1
DOIs	https://doi.org/10.1093/MNRAS/STAA1260
Publication status	Published - 2020
Externally published	Yes

Keywords

Galaxies: evolution
Galaxies: high-redshift

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1093/MNRAS/STAA1260

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Cullen, F., McLure, R. J., Dunlop, J. S., Carnall, A. C., McLeod, D. J., Shapley, A. E., Amorín, R., Bolzonella, M., Castellano, M., Cimatti, A., Cirasuolo, M., Cucciati, O., Fontana, A., Fontanot, F., Garilli, B., Guaita, L., Jarvis, M. J., Pentericci, L., Pozzetti, L., ... Saxena, A. (2020). The VANDELS survey: a strong correlation between Ly α equivalent width and stellar metallicity at 3 ≤ z ≤ 5. Monthly Notices of the Royal Astronomical Society, 495(1), 1501-1510. https://doi.org/10.1093/MNRAS/STAA1260

@article{a7ca9a2591f64e14931b1ee7fec03d48,

title = "The VANDELS survey: a strong correlation between Ly α equivalent width and stellar metallicity at 3 ≤ z ≤ 5",

abstract = "We present the results of a new study investigating the relationship between observed Ly α equivalent width (Wλ(Ly α)) and the metallicity of the ionizing stellar population (Z★) for a sample of 768 star-forming galaxies at 3 ≤ z ≤ 5 drawn from the VANDELS survey. Dividing our sample into quartiles of rest-frame Wλ(Ly α) across the range −58 {\AA} ≾ Wλ(Ly α) ≾ 110 {\AA}, we determine Z★ from full spectral fitting of composite far-ultraviolet spectra and find a clear anticorrelation between Wλ(Ly α) and Z★. Our results indicate that Z★ decreases by a factor ≳ 3 between the lowest Wλ(Ly α) quartile (≺Wλ(Ly α)≻ = −18 {\AA}) and the highest Wλ(Ly α) quartile (≺Wλ(Ly α)≻ = 24 {\AA}). Similarly, galaxies typically defined as Lyman alpha emitters (LAEs; Wλ(Ly α) > 20 {\AA}) are, on average, metal poor with respect to the non-LAE galaxy population (Wλ(Ly α) ≤ 20 {\AA}) with Z★non-LAE ≳ 2 × Z★LAE. Finally, based on the best-fitting stellar models, we estimate that the increasing strength of the stellar ionizing spectrum towards lower Z★ is responsible for ≈15−25 per cent of the observed variation in Wλ(Ly α) across our sample, with the remaining contribution (≈75−85 per cent) being due to a decrease in the H I/dust covering fractions in low- Z★ galaxies.",

keywords = "Galaxies: evolution, Galaxies: high-redshift",

author = "F. Cullen and McLure, {R. J.} and Dunlop, {J. S.} and Carnall, {A. C.} and McLeod, {D. J.} and Shapley, {A. E.} and R. Amor{\'i}n and M. Bolzonella and M. Castellano and A. Cimatti and M. Cirasuolo and O. Cucciati and A. Fontana and F. Fontanot and B. Garilli and L. Guaita and Jarvis, {M. J.} and L. Pentericci and L. Pozzetti and M. Talia and G. Zamorani and A. Calabr{\`o} and G. Cresci and Fynbo, {J. P.U.} and Hathi, {N. P.} and M. Giavalisco and A. Koekemoer and F. Mannucci and A. Saxena",

note = "Publisher Copyright: {\textcopyright}C 2020 The Author(s)",

year = "2020",

doi = "10.1093/MNRAS/STAA1260",

language = "English",

volume = "495",

pages = "1501--1510",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

publisher = "Oxford University Press",

number = "1",

}

Cullen, F, McLure, RJ, Dunlop, JS, Carnall, AC, McLeod, DJ, Shapley, AE, Amorín, R, Bolzonella, M, Castellano, M, Cimatti, A, Cirasuolo, M, Cucciati, O, Fontana, A, Fontanot, F, Garilli, B, Guaita, L, Jarvis, MJ, Pentericci, L, Pozzetti, L, Talia, M, Zamorani, G, Calabrò, A, Cresci, G, Fynbo, JPU, Hathi, NP, Giavalisco, M, Koekemoer, A, Mannucci, F & Saxena, A 2020, 'The VANDELS survey: a strong correlation between Ly α equivalent width and stellar metallicity at 3 ≤ z ≤ 5', Monthly Notices of the Royal Astronomical Society, vol. 495, no. 1, pp. 1501-1510. https://doi.org/10.1093/MNRAS/STAA1260

TY - JOUR

T1 - The VANDELS survey

T2 - a strong correlation between Ly α equivalent width and stellar metallicity at 3 ≤ z ≤ 5

AU - Cullen, F.

AU - McLure, R. J.

AU - Dunlop, J. S.

AU - Carnall, A. C.

AU - McLeod, D. J.

AU - Shapley, A. E.

AU - Amorín, R.

AU - Bolzonella, M.

AU - Castellano, M.

AU - Cimatti, A.

AU - Cirasuolo, M.

AU - Cucciati, O.

AU - Fontana, A.

AU - Fontanot, F.

AU - Garilli, B.

AU - Guaita, L.

AU - Jarvis, M. J.

AU - Pentericci, L.

AU - Pozzetti, L.

AU - Talia, M.

AU - Zamorani, G.

AU - Calabrò, A.

AU - Cresci, G.

AU - Fynbo, J. P.U.

AU - Hathi, N. P.

AU - Giavalisco, M.

AU - Koekemoer, A.

AU - Mannucci, F.

AU - Saxena, A.

PY - 2020

Y1 - 2020

N2 - We present the results of a new study investigating the relationship between observed Ly α equivalent width (Wλ(Ly α)) and the metallicity of the ionizing stellar population (Z★) for a sample of 768 star-forming galaxies at 3 ≤ z ≤ 5 drawn from the VANDELS survey. Dividing our sample into quartiles of rest-frame Wλ(Ly α) across the range −58 Å ≾ Wλ(Ly α) ≾ 110 Å, we determine Z★ from full spectral fitting of composite far-ultraviolet spectra and find a clear anticorrelation between Wλ(Ly α) and Z★. Our results indicate that Z★ decreases by a factor ≳ 3 between the lowest Wλ(Ly α) quartile (≺Wλ(Ly α)≻ = −18 Å) and the highest Wλ(Ly α) quartile (≺Wλ(Ly α)≻ = 24 Å). Similarly, galaxies typically defined as Lyman alpha emitters (LAEs; Wλ(Ly α) > 20 Å) are, on average, metal poor with respect to the non-LAE galaxy population (Wλ(Ly α) ≤ 20 Å) with Z★non-LAE ≳ 2 × Z★LAE. Finally, based on the best-fitting stellar models, we estimate that the increasing strength of the stellar ionizing spectrum towards lower Z★ is responsible for ≈15−25 per cent of the observed variation in Wλ(Ly α) across our sample, with the remaining contribution (≈75−85 per cent) being due to a decrease in the H I/dust covering fractions in low- Z★ galaxies.

AB - We present the results of a new study investigating the relationship between observed Ly α equivalent width (Wλ(Ly α)) and the metallicity of the ionizing stellar population (Z★) for a sample of 768 star-forming galaxies at 3 ≤ z ≤ 5 drawn from the VANDELS survey. Dividing our sample into quartiles of rest-frame Wλ(Ly α) across the range −58 Å ≾ Wλ(Ly α) ≾ 110 Å, we determine Z★ from full spectral fitting of composite far-ultraviolet spectra and find a clear anticorrelation between Wλ(Ly α) and Z★. Our results indicate that Z★ decreases by a factor ≳ 3 between the lowest Wλ(Ly α) quartile (≺Wλ(Ly α)≻ = −18 Å) and the highest Wλ(Ly α) quartile (≺Wλ(Ly α)≻ = 24 Å). Similarly, galaxies typically defined as Lyman alpha emitters (LAEs; Wλ(Ly α) > 20 Å) are, on average, metal poor with respect to the non-LAE galaxy population (Wλ(Ly α) ≤ 20 Å) with Z★non-LAE ≳ 2 × Z★LAE. Finally, based on the best-fitting stellar models, we estimate that the increasing strength of the stellar ionizing spectrum towards lower Z★ is responsible for ≈15−25 per cent of the observed variation in Wλ(Ly α) across our sample, with the remaining contribution (≈75−85 per cent) being due to a decrease in the H I/dust covering fractions in low- Z★ galaxies.

KW - Galaxies: evolution

KW - Galaxies: high-redshift

UR - http://www.scopus.com/inward/record.url?scp=85091979874&partnerID=8YFLogxK

U2 - 10.1093/MNRAS/STAA1260

DO - 10.1093/MNRAS/STAA1260

M3 - Article

AN - SCOPUS:85091979874

SN - 0035-8711

VL - 495

SP - 1501

EP - 1510

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 1

ER -

The VANDELS survey: a strong correlation between Ly α equivalent width and stellar metallicity at 3 ≤ z ≤ 5

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Keywords

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