Revised Primordial Helium Abundance Based on New Atomic Data

By M. Peimbert, V. Luridiana, A. Peimbert. 2007

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We have derived a primordial helium abundance of Yp = 0.2477 ± 0.0029, based on new atomic physics computations of the recombination coefficients of He I and of the collisional excitation of the H I Balmer lines together with observations and photoionization models of metal-poor extragalactic H II regions. The new atomic data increase our previous determination of Yp by 0.0086, a very significant amount. By combining our Yp result with the predictions made by the standard big bang nucleosynthesis model, we find a baryon-to-photon ratio, η, in excellent agreement both with the η-value derived by the primordial deuterium abundance value observed in damped Lyα systems and with the one obtained from the WMAP observations.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/7a910eb1ac5f50564a8cb570b3b0f0ac3fc6d066

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Citations in the corpus

The Pisa pre-main sequence tracks and isochrones - A database covering a wide range of Z, Y, mass, and age values (2011, methodology): “For the cosmological value of Yp, we used both the recent WMAP estimate Yp = 0.2485 (Cyburt et al. 2004; Steigman 2006; Peimbert et al. 2007a,b) and an older estimate of Yp = 0.230 (Lequeux et al. 1979; Pagel & Simonson 1989; Olive et al. 1991), usually referred to as canonical Yp in several…”
CRITICAL STAR FORMATION RATES FOR REIONIZATION: FULL REIONIZATION OCCURS AT REDSHIFT z ≈ 7 (2012, unknown): “From the corresponding helium mass fraction Y = 0.2477 ± 0.0029 (Peimbert et al. 2007), we adopt a mean hydrogen number density n̄H = ρ̄b(1 − Y ) mH = (1.905 × 10−7 cm−3)(1 + z)3 .”
The VLT FLAMES Survey of Massive Stars: Rotation and Nitrogen Enrichment as the Key to Understanding Massive Star Evolution (2007, methodology): “Based on the recent discussion of the primordial helium abundance (Peimbert et al. 2007), we have updated the initial helium mass fraction for our LMC models to , which together with the metallicity of theY p 25.6% adopted chemical composition ( ) results in a hydro-Z p 0.5% gen mass fraction of .”
THE PRIMORDIAL ABUNDANCE OF 4He: EVIDENCE FOR NON-STANDARD BIG BANG NUCLEOSYNTHESIS (2010, background): “On the other hand, Peimbert et al. (2007) obtained Yp = 0.2477 ± 0.0029 based on a sample of 5 H ii regions, Porter et al. (2005) He i emissivities, and adopting non-zero temperature fluctuations.”
THE BARYON CENSUS IN A MULTIPHASE INTERGALACTIC MEDIUM: 30% OF THE BARYONS MAY STILL BE MISSING (2011, background): “This 4.6% baryon fraction corresponds to a mean comoving density, ρb = Ωbρcr = 4.24× 10−31 g cm−3, and a hydrogen number density nH = 1.90× 10−7 cm−3, assuming a primordial helium mass fraction Yp = 0.2477 (Peimbert et al. 2007).”
The physics of the intergalactic medium (2007, background): “B.4 below) and cosmic helium mass fraction Y ≃ 0.2477 ± 0.0029 (Peimbert et al., 2007), and to a Hubble Constant of H0 = 70 km s −1 Mpc−1 (§ II.”
A new determination of the primordial He abundance using the He i λ10830 Å emission line: cosmological implications (2014, methodology): “Most of the known systematic effects have generally been taken into account in the most recent work on the determination of the helium abundance(e.g. Izotov et al. 2007; Izotov & Thuan 2010; Peimbert et al. 2007; Aver et al. 2010, 2012, 2013).”
A MEASUREMENT OF THE DAMPING TAIL OF THE COSMIC MICROWAVE BACKGROUND POWER SPECTRUM WITH THE SOUTH POLE TELESCOPE (2011, background): “The primordial 4He abundance may also be inferred from observations of low-metallicity extragalactic HII regions (Izotov et al. 2007; Peimbert et al. 2007; Izotov & Thuan 2010; Aver et al. 2010, 2011).”
The Low-z Intergalactic Medium. III. H I and Metal Absorbers at z < 0.4 (2007, unknown): “Our adopted formula was Ω (OVI) IGM = ( H0 c ρcr,0 ) µmH Z (O/H)⊙ fOVI × (7) ∫ Nmax Nmin [ dN (log NOVI) dz ] 〈NOVI〉 d log NOVI , where µ = 1.32 for low-metallicity gas and primordial helium, Yp ≈ 0.2477± 0.0029 (Peimbert et al. 2007).”
SEVEN-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP) OBSERVATIONS: COSMOLOGICAL INTERPRETATION (2010, result): “This value is broadly consistent with the helium abundances estimated from observations of low-metallicity extragalactic ionized (HII) regions, Yp ≃ 0.24 − 0.25 (Gruenwald et al. 2002; Izotov & Thuan 2004; Olive & Skillman 2004; Fukugita & Kawasaki 2006; Peimbert et al. 2007).”
A new route towards merging massive black holes (2016, background): “The helium abundance was set in such a way that it increased linearly from its primordial value Y = 0.2477 (Peimbert et al. 2007) at Z = 0 to Y = 0.28 at Z = Z .”