Wide-field VLBA observations of theChandradeep field South

metallicity of starburst galaxies in chandra deep field south (cdf-s) , at 0.5

چکیده یکی از پارامترهای اصلی در دنبال کردن تاریخچه ی تشکیل ستاره ها و تحول کهکشان ها، مطالعه ی میزان فراوانی عناصر آن ها است. در این پایان نامه برای مطالعه ی همبستگی میان فراوانی فلزی و جرم ستاره ای کهکشان ها، از داده های طیفی 89 کهکشانِ ستاره زا استفاده شده است. طیف ها توسط طیف نگار فورس2 از میدان ژرف جنوبی چاندرا گرفته شده و جابه جایی به سرخ طیف ها همه بزرگتر از نیم و کوچکتر از یک هستند. جر...

Field observations on population fluctuations of chicory aphids 1970

Vlba Observations of G5.89 0.39: Oh Masers and Magnetic Field Structure

We present VLBA observations of 1667 MHz OH maser emission from the massive star formation region G5.89 0.39. The observations were phase-referenced, allowing the absolute positions of the masers to be obtained. The 1667MHzmasers have radial velocities that span 50 km s 1 but show little evidence of tracing the bipolar molecular outflow, as has been claimed in previous studies. We identify 23 Z...

VLBA Observations of Blazars

VLBI observations of blazars provide the closest look at compact jets that are thought to be responsible for the variable emission of blazars from radio to γ-ray wavelengths. It appears that flux variability at different wavelengths is connected to changes in jet structure near its base. The changes happen on timescales of weeks or less, which require frequent VLBI monitoring to follow. Current...

Toward Epoch of Reionization Measurements with Wide-field Radio Observations

This paper explores the potential for statistical epoch of reionization (EOR) measurements using wide-field radio observations. New developments in low-frequency radio instrumentation and signal processing allow very sensitive EOR measurements, and the analysis techniques enabled by these advances offer natural ways of separating the EOR signal from the residual foreground emission. This paper ...