Deuterium abundance and Population III remnants

Ramadurai, S.; Rees, M. J.

doi:10.1093/mnras/215.1.53p

Cited by 13 publications

(9 citation statements)

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“…As a consequence, nuclei with energies > 10 MeV per nucleon are abundant and spallation processes become possible (Ramadurai & Rees 1985, Jin 1990). Ramadurai & Rees (1985) considered "ion tori" around pregalactic massive Pop III remnants and examined deuterium production and its implication for big bang nucleosynthesis. Jin (1990) studied the production of 7 Li and other light nuclei in ion tori and derived constraints on the light element enrichment of the Galaxy.…”

Section: Introductionmentioning

confidence: 99%

Lithium Production in Hot Advection‐dominated Accretion Flows in Soft X‐Ray Transients

Yi¹,

Narayan²

1997

ApJ

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High Li abundances have been reported in the late-type secondaries of Ðve soft X-ray transients (SXTs) : V404 Cyg, A0620[00, GS 2000]25, Nova Mus 1991, and Cen X-4. Since Li is likely to be depleted in stars of this type, the origin of the Li is puzzling. Li has not been seen in similar secondaries of cataclysmic variables, which suggests that the high Li abundance is not due to an anomalous suppression of Li depletion in close binaries. SXTs in the quiescent state have been modeled in terms of hot advection-dominated accretion Ñows (ADAFs), in which the ions are essentially at virial temperature. At such temperatures, Li production via a-a spallation is possible. We show that ADAFs can produce sufficient Li via spallation to explain the observations in the black hole SXTs V404 Cyg, A0620[00, GS 2000]25, and Nova Mus 1991. If this explanation is correct, it is the Ðrst independent conÐrmation that accretion Ñows in quiescent SXTs have a two-temperature plasma with ion temperature much higher than electron temperature. Depending on the Li depletion timescale in the secondary, which may range between 107È109 yr, the model requires D10~4 to 10~6 of the accreted mass to be intercepted by the secondary after undergoing Li production and being ejected. In the case of the neutron star SXT, Cen X-4, we can explain the observed Li only if the mass-accretion rate is D10~3 times the Eddington rate and if there is enhanced ejection due to a propeller e †ect. We discuss possible observational tests of this proposal. Li production during outbursts could be quite important and may even dominate over the production during quiescence, but the estimate of the Li yield is uncertain. We calculate the expected luminosity in gamma-ray lines due to the production of excited Li and Be nuclei, but conclude that the line cannot be detected with current instruments.

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Section: Introductionmentioning

confidence: 99%

Lithium Production in Hot Advection‐dominated Accretion Flows in Soft X‐Ray Transients

Yi¹,

Narayan²

1997

ApJ

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“…These objects would now constitute the dark matter in galactic halos and clusters of galaxies. The paper showed that accretion onto these early black holes could generate a background of energetic photons at high z; photodisintegration of 4 He by these photons would modify the light element abundances of the \uncollapsed" baryons so as to reconcile the measured cosmic abundances with a primordial b of up to 0.2 (for an earlier version of this idea see Ramadurai & Rees 1985). We here explore some further aspects of this idea, the main attractive feature of which is that it obviates the need for non-baryonic dark matter.…”

Section: Introductionmentioning

confidence: 99%

Massive black holes and light-element nucleosynthesis in a baryonic universe

Gnedin

Ostriker²,

Rees³

1995

ApJ

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We reexamine the model proposed by Gnedin and Ostriker (1992) in which Jeans' mass black holes (M BH 10 6 M) form shortly after decoupling. There is no nonbaryonic dark matter in this model, but we examine the possibility that b is considerably larger than given by normal nucleosynthesis. Here we allow for the fact that much of the high baryon-to-photon ratio material will collapse, leaving the universe of remaining material with light element abundances more in accord with the residual baryonic density (10 ?2) than with 0 and the initial baryonic density (10 ?1). We nd that no reasonable model can be made with random phase density uctuations, if the power on scales smaller than 10 6 M is as large as expected. However, phase correlated models of the type that might occur in connection with topological singularities can be made with b h 2 = 0:013 0:001, 0:15 < 0 < 0:4 which are either at (= 1 ? 0) or open (= 0) and which satisfy all the observational constraints which we apply, including the large baryon to total mass ratio found in the X-ray clusters. The remnant baryon density is thus close to that obtained in the standard picture (b h 2 = 0:0125 0:0025, Walker et al 1991). The spectral index implied for uctuations in the baryonic isocurvature scenario, ?1 < m < 0, is in the range expected by other arguments based on large scale structure and microwave uctuation constraints. The dark matter in this picture is in the form of massive black holes. Accretion onto them at early epochs releases high energy photons which signi cantly heat and reionize the universe. But photodissociation does not materially change light element abundances. A typical model gives y 1 10 ?5 , n e =n H (z = 30) 0:1 and a di use-ray background at 100 KeV near the COBE limit of the order of 10% of that observed which originates from high redshift quasars. Reionization in { 3 { this model occurs at redshift 600 and reaches (H II=H tot) 0:1 ? 0:2. { 4 {

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“…We adopt ∆t = 100 Myr and f exp = 0.5 all along, but our results can be trivially scaled to other values. A value of order unity for the expelled fraction f exp has been frequently used [14,15] as the presence of powerful jets -both observationally confirmed and theoretically expected [13] -can lead to significant ejection in hot tori.…”

Section: Nucleosynthesis In Hot Accretion Torimentioning

confidence: 99%

Lithium Synthesis in Microquasar Accretion

Iocco

Pato

2012

Phys. Rev. Lett.

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We study the synthesis of lithium isotopes in the hot tori formed around stellar mass black holes by accretion of the companion star. We find that sizable amounts of both stable isotopes 6Li and 7Li can be produced, the exact figures varying with the characteristics of the torus and reaching as much as 10(-2) M⊙ for each isotope. This mass output is enough to contaminate the entire Galaxy at a level comparable with the original, pregalactic amount of lithium and to overcome other sources such as cosmic-ray spallation or stellar nucleosynthesis.

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Deuterium abundance and Population III remnants

Cited by 13 publications

References 0 publications

Lithium Production in Hot Advection‐dominated Accretion Flows in Soft X‐Ray Transients

Lithium Production in Hot Advection‐dominated Accretion Flows in Soft X‐Ray Transients

Massive black holes and light-element nucleosynthesis in a baryonic universe

Lithium Synthesis in Microquasar Accretion

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