Spectral Line Sources Spectral Line VLBI Chris Phillips JIVE The Netherlands · VLBI High brightness temperatures · Masers : Galactic · OH, H2O, SiO, CH3OH Extragalactic · OH, H2O · Extra-galactic HI absorption Image courtesy of Lincoln Greenhill, CfA VLBI Group See also: Hernstein etal , 1999, Nature, 400, 539 Miyoshi etal , 1995, Nature, 373, 127 1 SiO masers in TX Cam Movie courtesy of Phil Diamond, Jodrell Bank SiO masers in Orion BN/KL Greenhill ...

... We will consider the rms, (K), for observations with a receiver of system temperature, T , frequency resolution, per polarization, and total integration time per observing cycle, . ... For ``in-band'' frequency switching, the line under investigation is always in the observing band. ... Position Switching or ``Out-of-Band'' Frequency Switching: Here the line is only observed for one half of the time, with noise being present all of the time. ...

... Дни открытых дверей к юбилею САО РАН (12-14 апреля 2016 г.) . Международная конференция "Dark Ages and White Nights (Spectroscopy of the CMB)" (20-24 июня 2016 г.) . ... Международная конференция MULTI-SPIN GALAXIES - 2016 (26-30 сентября 2016 г.) . Международная астрономическая конференция "Физика звезд: от коллапса до коллапса" (3-7 октября 2016 г.) Архив . ... Подробнее.. ... 10.02.16 . ... БТА в реальном времени . ... Цейсс-1000 в реальном времени . ... Последнее обновление: 22/03/2016 ...

... 640W A survey of ultracompact (UC) Hii regions has been carried out by searching for 6.669-GHz methanol maser emission from a sample of 535 IRAS-selected candidates. A total of 201 candidates exhibit methanol emission. These sources have been used, in conjunction with previously identified UC Hii regions, to provide a base for further studies of such regions. ... Methanol maser and/or radio continuum emission is found in 364 cases towards IRAS-selected regions. ...

... Thomson's multiple window method of spectral estimationthomson provides a very good estimate of the power spectrum by measuring the energy contained within a collection of rectangular shaped frequency intervals. ... Often, much of the fine structure of a spectral estimate is due to noise. It should be stressed that while other methods of spectral estimation (such as the Welchoppenheim method) exist, the Thomson method is particularly noteworthy for its precisely defined rectangular frequency bins. ...

Static Fourier spectrometers are often used for spectral measurements of the ionosphere emissions. There are two main advantages of Fourier spectrometers (FS) - large geometric factor and high spectral resolution; these parameters are two orders better than for grating spectral instruments. ... In scanning Fourier spectrometer optical and electric modulation of signal is used to avoid this problem, for static Fourier spectrometer there are no such ways. ...

... Bojan Nikolic web pages (r. 329) . ALMA . ... These errors are due to the refractive effects of the Earth?s atmosphere, specifically due to the (tropospheric) water vapour. ... Making use of information on baselines this long will require very accurate calibration and correction of atmospheric phase errors. ... The design of the ALMA phase correction system is summarised in Nikolic et al 2013 . Introduction to phase correction for ALMA . ALMA Goals . ALMA Phase correction strategy . ...

Saturation is a common problem for narrow band filter images of galaxy nuclei. Often the surface brightness of the emission line is estimated from ground-based images with 1 " resolution; sometimes line fluxes are quoted for apertures several arcseconds in radius. However, at HST resolution, much of this flux may occur in a single unresolved spot at the galaxy nucleus, thus leading to saturated images. ... Voice: (410) 338-1082 . ...