Detecting the Earliest Galaxies through Two New Sources of 21 Centimeter Fluctuations
نویسندگان
چکیده
منابع مشابه
Detecting the Earliest Galaxies through Two New Sources of 21cm Fluctuations
The first galaxies that formed at a redshift z ∼ 20–30 emitted continuum photons with energies between the Lyα and Lyman limit wavelengths of hydrogen, to which the neutral universe was transparent except at the Lyman-series resonances. As these photons redshifted or scattered into the Lyα resonance they coupled the spin temperature of the 21cm transition of hydrogen to the gas temperature, all...
متن کاملDetecting Early Galaxies Through Their 21-cm Signature
New observations over the next few years of the emission of distant objects will help unfold the chapter in cosmic history around the era of the first galaxies. These observations will use the neutral hydrogen emission or absorption at a wavelength of 21-cm as a detector of the hydrogen abundance. We predict the signature on the 21-cm signal of the early generations of galaxies. We calculate th...
متن کاملThe 21 centimeter forest
We examine the prospects for studying the pre-reionization intergalactic medium (IGM) through the so-called 21 cm forest in spectra of bright high-redshift radio sources. We first compute the evolution of the mean optical depth τ for models that include X-ray heating of the IGM gas, Wouthuysen-Field coupling, and reionization. Under most circumstances, the spin temperature TS grows large well b...
متن کاملStudying the sources of cosmic reionization with 21-cm fluctuations
We explore the ability of measurements of the 21-cm power spectrum during reionization to enable the simultaneous reconstruction of the reionization history and the properties of the ionizing sources. For various sets of simulated 21-cm measurements, we perform maximum likelihood fits in order to constrain the reionization and galaxy formation histories. We employ a flexible six-parameter model...
متن کاملa case study of the two translators of the holy quran: tahereh saffarzadeh and laleh bakhtiar
بطورکلی، کتاب های مقدسی همچون قران کریم را خوانندگان میتوان مطابق با پیش زمینه های مختلفی که درند درک کنند. محقق تلاش کرده نقش پیش زمینه اجتماعی-فرهنگی را روی ایدئولوژی های مترجمین زن و در نتیجه تاثیراتش را روی خواندن و ترجمه آیات قرآن کریم بررسی کند و ببیند که آیا تفاوت های واژگانی عمده ای میان این مترجمین وجود دارد یا نه. به این منظور، ترجمه 24 آیه از آیات قرآن کریم مورد بررسی مقایسه ای قرار ...
15 صفحه اولذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2005
ISSN: 0004-637X,1538-4357
DOI: 10.1086/429954