The VANDELS survey:: A strong correlation between Lyα 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 Lyα 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

School of Physics and Astronomy

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We present the results of a new study investigating the relationship between observed Lyα equivalent width (Wλ(Lyα)) 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(Lyα) across the range −58Å≲ Wλ(Lyα) ≲110Å we determine Z⋆ from full spectral fitting of composite far-ultraviolet (FUV) spectra and find a clear anti-correlation between Wλ(Lyα) and Z⋆. Our results indicate that Z⋆ decreases by a factor ≳3 between the lowest Wλ(Lyα) quartile (⟨Wλ(Lyα)⟩=−18Å) and the highest Wλ(Lyα) quartile (⟨Wλ(Lyα)⟩=24Å). Similarly, galaxies typically defined as Lyman Alpha Emitters (LAEs; Wλ(Lyα) >20Å) are, on average, metal poor with respect to the non-LAE galaxy population (Wλ(Lyα) ≤20Å) 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% of the observed variation in Wλ(Lyα) across our sample, with the remaining contribution (≃75−85%) being due to a decrease in the HI/dust covering fractions in low Z⋆ galaxies.

Original language	English
Pages (from-to)	1501-1510
Number of pages	11
Journal	Monthly Notices of the Royal Astronomical Society
Volume	495
Issue number	1
Early online date	9 May 2020
DOIs	https://doi.org/10.1093/mnras/staa1260
Publication status	Published - 1 Jun 2020

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astro-ph.GA

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10.1093/mnras/staa1260

FergusCullen_VandelsLya_2020Accepted author manuscript, 764 KB

Fergus Cullen
- School of Physics and Astronomy - Reader in Galaxy Evolution
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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 Lyα 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{e7ce8df0d4054f3b98c7621fbb747ada,

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

abstract = "We present the results of a new study investigating the relationship between observed Lyα equivalent width (Wλ(Lyα)) 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(Lyα) across the range −58{\AA}≲ Wλ(Lyα) ≲110{\AA} we determine Z⋆ from full spectral fitting of composite far-ultraviolet (FUV) spectra and find a clear anti-correlation between Wλ(Lyα) and Z⋆. Our results indicate that Z⋆ decreases by a factor ≳3 between the lowest Wλ(Lyα) quartile (⟨Wλ(Lyα)⟩=−18{\AA}) and the highest Wλ(Lyα) quartile (⟨Wλ(Lyα)⟩=24{\AA}). Similarly, galaxies typically defined as Lyman Alpha Emitters (LAEs; Wλ(Lyα) >20{\AA}) are, on average, metal poor with respect to the non-LAE galaxy population (Wλ(Lyα) ≤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% of the observed variation in Wλ(Lyα) across our sample, with the remaining contribution (≃75−85%) being due to a decrease in the HI/dust covering fractions in low Z⋆ galaxies. ",

keywords = "astro-ph.GA",

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 = "10 pages, 6 figures, MNRAS accepted",

year = "2020",

month = jun,

day = "1",

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 Lyα 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 Lyα 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.

N1 - 10 pages, 6 figures, MNRAS accepted

PY - 2020/6/1

Y1 - 2020/6/1

N2 - We present the results of a new study investigating the relationship between observed Lyα equivalent width (Wλ(Lyα)) 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(Lyα) across the range −58Å≲ Wλ(Lyα) ≲110Å we determine Z⋆ from full spectral fitting of composite far-ultraviolet (FUV) spectra and find a clear anti-correlation between Wλ(Lyα) and Z⋆. Our results indicate that Z⋆ decreases by a factor ≳3 between the lowest Wλ(Lyα) quartile (⟨Wλ(Lyα)⟩=−18Å) and the highest Wλ(Lyα) quartile (⟨Wλ(Lyα)⟩=24Å). Similarly, galaxies typically defined as Lyman Alpha Emitters (LAEs; Wλ(Lyα) >20Å) are, on average, metal poor with respect to the non-LAE galaxy population (Wλ(Lyα) ≤20Å) 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% of the observed variation in Wλ(Lyα) across our sample, with the remaining contribution (≃75−85%) being due to a decrease in the HI/dust covering fractions in low Z⋆ galaxies.

AB - We present the results of a new study investigating the relationship between observed Lyα equivalent width (Wλ(Lyα)) 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(Lyα) across the range −58Å≲ Wλ(Lyα) ≲110Å we determine Z⋆ from full spectral fitting of composite far-ultraviolet (FUV) spectra and find a clear anti-correlation between Wλ(Lyα) and Z⋆. Our results indicate that Z⋆ decreases by a factor ≳3 between the lowest Wλ(Lyα) quartile (⟨Wλ(Lyα)⟩=−18Å) and the highest Wλ(Lyα) quartile (⟨Wλ(Lyα)⟩=24Å). Similarly, galaxies typically defined as Lyman Alpha Emitters (LAEs; Wλ(Lyα) >20Å) are, on average, metal poor with respect to the non-LAE galaxy population (Wλ(Lyα) ≤20Å) 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% of the observed variation in Wλ(Lyα) across our sample, with the remaining contribution (≃75−85%) being due to a decrease in the HI/dust covering fractions in low Z⋆ galaxies.

KW - astro-ph.GA

U2 - 10.1093/mnras/staa1260

DO - 10.1093/mnras/staa1260

M3 - Article

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 Lyα equivalent width and stellar metallicity at 3≤z≤5

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