Cosmological HII Regions
نویسندگان
چکیده
منابع مشابه
The Structure and Evolution of Early Cosmological Hii Regions
We study the formation and evolution of Hii regions around the first stars formed at redshifts z = 10 − 30. We use a one-dimensional Lagrangian hydrodynamics code which self-consistently incorporates radiative transfer and non-equilibrium primordial gas chemistry. The star-forming region is defined as a spherical dense molecular gas cloud with a Population III star embedded at the center. We ex...
متن کاملSmooth Boundaries to Cosmological HII regions from Galaxy Clustering
The HII regions around quasars and galaxies at redshifts beyond the epoch of reionisation will provide prime targets for upcoming 21cm campaigns using a new generation of low-frequency radio observatories. Here we show that the boundaries of these HII regions will not be sharp. Rather, the clustering of sources near massive galaxies results in a neutral fraction that rises gradually towards lar...
متن کاملAnomalous emission from HII regions
Spinning dust appears to be the best explanation for the anomalous emission that has been observed at ∼ 10 − 60 GHz. One of the best examples of spinning dust comes from a HII region in the Perseus molecular cloud. Observations of other HII regions also show tentative evidence for excess emission at frequencies ∼ 30 GHz, although at lower emissivity levels. A new detection of excess emission at...
متن کاملCosmological Hii Bubble Growth during Reionization
We present general properties of ionized hydrogen (HII) bubbles and their growth based on a stateof-the-art large-scale (100 Mpc/h) cosmological radiative transfer simulation. The simulation resolves all halos with atomic cooling at the relevant redshifts and simultaneously performs radiative transfer and dynamical evolution of structure formation. Our major conclusions include: (1) for signifi...
متن کاملHII Galaxies as deep cosmological probes
We re-investigated the use of the Hubble diagram to measure the cosmological constant (Λ) and the mass density of the Universe (ΩM ). We find an important focusing effect in Λ for redshifts about 3. This effect implies that the apparent magnitude of a standard candle at redshifts z=2-3 has almost no dependence on Λ for ΩM > 0.2. This means that ΩM can be measured independently of ΩΛ by targetin...
متن کاملذخیره 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: Symposium - International Astronomical Union
سال: 1987
ISSN: 0074-1809
DOI: 10.1017/s0074180900150533