The Deuterium Abundance in QSO Absorption Systems : A Mesoturbulent Approach
نویسنده
چکیده
A new method, based on simulated annealing technique and aimed at the inverse problem in the analysis of intergalactic or interstellar complex spectra of hydrogen and metal lines, is outlined. We consider the process of line formation in clumpy stochastic media accounting for fluctuating velocity and density fields self-consistently. Two examples of the analysis of ‘H+D’-like absorptions seen at za = 3.514 and 3.378 towards APM 08279+5255 are presented.
منابع مشابه
Deuterium to hydrogen towards QSO 1009+2956 from a mesoturbulent model
We present a new analysis of the deuterium absorption at z = 2.504 towards the quasar Q1009+2956 using the mesoturbulent model which accounts for possible correlations in the large scale velocity field. We obtain a slightly higher deuterium-tohydrogen ratio D/H ≃ (3.5 − 5.0) × 10 as compared with the recent measurement D/H = (3.3 − 4.5) × 10 (68% C.L.) performed by Burles & Tytler (1998b) using...
متن کاملON THE MEASUREMENTS OF D/H IN QSO ABSORPTION SYSTEMS Closing in on the primordial abundance of deuterium
We present our measurements of the deuterium to hydrogen ratio (D/H) in QSO absorption systems, which give D/H = 3.40 ± 0.25× 10 based on analysis of four independent systems. We discuss the properties of two systems which provide the strongest constraints on D/H. We outline the systematic effects involved in measurements of D/H and introduce a sophisticated method of analysis which properly ac...
متن کاملMeasurements of the deuterium abundance in quasar absorption systems
Observational constraints on the primordial deuterium-tohydrogen ratio (D/H) can test theories of the early universe and provide constraints on models of big bang nucleosynthesis (BBN). We measure deuterium absorption in high-redshift, metal-poor QSO absorption systems and directly infer the value of primordial D/H. We present two measurements of D/H, and find D/H = 3.3 ± 0.3 × 10 at z = 3.572 ...
متن کاملTracking the Post-bbn Evolution of Deuterium
The primordial abundance of deuterium produced during Big Bang Nucleosynthesis (BBN) depends sensitively on the universal ratio of baryons to photons, an important cosmological parameter probed independently by the Cosmic Microwave Background (CMB) radiation. Observations of deuterium in high-redshift, low-metallicity QSO Absorption Line Systems (QSOALS) provide a key baryometer, determining th...
متن کاملThe Cosmological Baryon Density from the Deuterium Abundance at a redshift z = 3 . 57
The primordial ratio of the number of deuterium to hydrogen nuclei (D/H) created in big bang nucleosynthesis is the most sensitive measure of the cosmological baryon to photon ratio and the cosmological density of baryons Ω b (1-5). In the interstellar medium (ISM) of our Galaxy D/H = 1.6 ± 0.1 × 10 −5 (6), which places a strict lower limit on the primordial abundance, because stars reduce the ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2000