Age Effects in Giant Extragalactic HII Regions
نویسندگان
چکیده
منابع مشابه
On the structure of giant HII regions and HII galaxies
We review the structural properties of giant extragalactic HII regions and HII galaxies based on two dimensional hydrodynamic calculations, and propose an evolutionary sequence that accounts for their observed detailed structure. The model assumes a massive and young stellar cluster surrounded by a large collection of clouds. These are thus exposed to the most important star-formation feedback ...
متن کاملNarrowband CCD Photometry of Giant HII Regions
We have obtained accurate CCD narrow band Hβ and Hα photometry of Giant HII Regions in M 33, NGC 6822 and M 101. Comparison with previous determinations of emission line fluxes show large discrepancies; their probable origins are discussed. Combining our new photometric data with global velocity dispersion (σ) derived from emission line widths we have reviewed the L(Hβ)) − σ relation. A reanaly...
متن کاملSampling effects in the emission line spectra of HII regions
The combination of stellar population synthesis models and photoionization models allows a better understanding of the spectral features of HII regions and HII galaxies. In this work we show that sampling effects in the initial mass function (IMF) are very important in the low cluster mass case. To this aim, we compute photoionization models ionized by realistic clusters made up of various comb...
متن کاملAn extragalactic HII region in the Virgo cluster ?
We present spectroscopic observations for six emission-line objects projected onto the Virgo cluster. These sources have been selected from narrow band (Hα + [NII]) images showing faint detectable continuum emission and EW > 100Å. Five of these sources result [OIII]λ5007 emitters at z ∼ 0.31, while one 122603+130724 is confirmed to be an HII region belonging to the Virgo cluster. This point-lik...
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 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: International Astronomical Union Colloquium
سال: 1989
ISSN: 0252-9211
DOI: 10.1017/s0252921100024118