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Radio astronomical observations have very poor signal to noise ratios, unlike in other disciplines. On the other hand, it is possible to observe the object of interest for long time intervals as well as using a wider bandwidth.…

天体物理学 · 物理学 2008-09-02 Sarod Yatawatta

We present the first detection of carbon radio recombination line absorption along the line of sight to Cygnus A. The observations were carried out with the LOw Frequency ARray in the 33 to 57 MHz range. These low frequency radio…

星系天体物理 · 物理学 2015-06-18 J. B. R. Oonk , R. J. van Weeren , F. Salgado , L. K. Morabito , A. G. G. M. Tielens , H. J. A. Rottgering , A. Asgekar , G. J. White , A. Alexov , J. Anderson , I. M. Avruch , F. Batejat , R. Beck , M. E. Bell , I. van Bemmel , M. J. Bentum , G. Bernardi , P. Best , A. Bonafede , F. Breitling , M. Brentjens , J. Broderick , M. Brueggen , H. R. Butcher , B. Ciardi , J. E. Conway , A. Corstanje , F. de Gasperin , E. de Geus , M. de Vos , S. Duscha , J. Eisloeffel , D. Engels , J. van Enst , H. Falcke , R. A. Fallows , R. Fender , C. Ferrari , W. Frieswijk , M. A. Garrett , J. Griessmeier , J. P. Hamaker , T. E. Hassall , G. Heald , J. W. T. Hessels , M. Hoeft , A. Horneffer , A. van der Horst , M. Iacobelli , N. J. Jackson , E. Juette , A. Karastergiou , W. Klijn , J. Kohler , V. I. Kondratiev , M. Kramer , M. Kuniyoshi , G. Kuper , J. van Leeuwen , P. Maat , G. Macario , G. Mann , S. Markoff , J. P. McKean , M. Mevius , J. C. A. Miller-Jones , J. D. Mol , D. D. Mulcahy , H. Munk , M. J. Norden , E. Orru , H. Paas , M. Pandey-Pommier , V. N. Pandey , R. Pizzo , A. G. Polatidis , W. Reich , A. M. M. Scaife , A. Schoenmakers , D. Schwarz , A. Shulevski , J. Sluman , O. Smirnov , C. Sobey , B. W. Stappers , M. Steinmetz , J. Swinbank , M. Tagger , Y. Tang , C. Tasse , S. ter Veen , S. Thoudam , C. Toribio , R. van Nieuwpoort , R. Vermeulen , C. Vocks , C. Vogt , R. A. M. J. Wijers , M. W. Wise , O. Wucknitz , S. Yatawatta , P. Zarka , A. Zensus

We present two novel methods for the estimation of the angular power spectrum of cosmic microwave background (CMB) anisotropies. We assume an absolute CMB experiment with arbitrary asymmetric beams and arbitrary sky coverage. The methods…

宇宙学与河外天体物理 · 物理学 2017-01-25 Elina Keihänen , Kimmo Kiiveri , Hannu Kurki-Suonio , Martin Reinecke

Context. During the last 30 years the surface of Pluto has been characterized, and its variability has been monitored, through continuous near-infrared spectroscopic observations. But in the visible range only few data are available. Aims.…

地球与行星天体物理 · 物理学 2016-01-13 V. Lorenzi , N. Pinilla-Alonso , J. Licandro , D. P. Cruikshank , W. M. Grundy , R. P. Binzel , J. P. Emery

Measurement of the angular power spectrum of the cosmic microwave background is most often based on a spherical harmonic analysis of the observed temperature anisotropies. Even if all-sky maps are obtained, however, it is likely that the…

天体物理学 · 物理学 2009-10-31 Daniel J. Mortlock , Anthony D. Challinor , Michael P. Hobson

Long-term spectroscopic monitoring campaigns on active galactic nuclei (AGNs) provide a wealth of information about its interior structure and kinematics. However, a number of the observations suffer from the contamination of second-order…

星系天体物理 · 物理学 2024-01-23 Wen-Zhe Xi , Kai-Xing Lu , Hai-Cheng Feng , Sha-Sha Li , Jin-Ming Bai , Rui-Lei Zhou , Hong-Tao Liu , Jian-Guo Wang

A new method for removing point radio sources and other non-Gaussian noise is proposed as a means of improving the accuracy of estimates of the angular power spectrum of the cosmic microwave background (CMB). The main idea of the method is…

天体物理学 · 物理学 2009-11-13 Anisa T. Bajkova

Atmospheric turbulence has a degrading effect on the image quality of long-range observation systems. As a result of various elements such as temperature, wind velocity, humidity, etc., turbulence is characterized by random fluctuations in…

计算机视觉与模式识别 · 计算机科学 2022-04-20 Engin Uzun , Ahmet Anil Dursun , Erdem Akagunduz

The mass-loss mechanism in normal K--M giant stars with small variability amplitudes is not yet understood, although they are the majority among red giant stars. We present high-spatial and high-spectral resolution observations of the 2.3…

太阳与恒星天体物理 · 物理学 2015-06-03 K. Ohnaka , K. -H. Hofmann , D. Schertl , G. Weigelt , F. Malbet , F. Massi , A. Meilland , Ph. Stee

Phase fluctuations introduced by the atmosphere are the main limiting factor in attaining diffraction limited performance in extended interferometric arrays at millimeter and submillimeter wavelengths. We report the results of C-PACS, the…

The Cosmology Large Angular Scale Surveyor (CLASS) is an experiment to measure the signature of a gravita-tional-wave background from inflation in the polarization of the cosmic microwave background (CMB). CLASS is a multi-frequency array…

In order to extract cosmological information from observations of the millimeter and submillimeter sky, foreground components must first be removed to produce an estimate of the cosmic microwave background (CMB). We developed a…

宇宙学与河外天体物理 · 物理学 2020-11-10 Matthew A. Petroff , Graeme E. Addison , Charles L. Bennett , Janet L. Weiland

The third flight of the Medium Scale Anisotropy Measurement (MSAM1), in June 1995, observed a new strip of sky, doubling the sky coverage of the original MSAM1 dataset. MSAM1 observes with a 0.5 deg beam size in four bands from 5-20 icm.…

Optical lightcurves can be used for the shape and spin reconstruction of asteroids. Due to unknown albedo, these models are scale-free. When thermal infrared data are available, they can be used for scaling the shape models and for deriving…

地球与行星天体物理 · 物理学 2017-08-02 Josef Durech , Marco Delbo , Benoit Carry , Josef Hanus , Victor Ali-Lagoa

This paper investigates three spectroscopic techniques - Tunable Diode Laser Absorption Spectroscopy (TDLAS), Wavelength Modulation Spectroscopy (WMS), and Heterodyne Phase Sensitive Dispersion Spectroscopy (HPSDS) - to evaluate their…

Cloud formations often obscure optical satellite-based monitoring of the Earth's surface, thus limiting Earth observation (EO) activities such as land cover mapping, ocean color analysis, and cropland monitoring. The integration of machine…

For microlensing case angular distances between images or typical astrometric shifts due to microlensing are about $10^{-5}-10^{-6} \mu as$. Such an angular resolution will be reached with the space space--ground interferometer Radioastron.…

天体物理学 · 物理学 2007-05-23 Alexander F. Zakharov

Atmospheric Cherenkov telescopes rely on the Earth's atmosphere as part of the detector. The presence of clouds affects observations and can introduce biases if not corrected for. Correction methods typically require an atmospheric profile,…

天体物理仪器与方法 · 物理学 2024-04-03 Julian Sitarek , Mario Pecimotika , Natalia Żywucka , Dorota Sobczyńska , Abelardo Moralejo , Dario Hrupec

The upcoming launch of the James Webb Space Telescope (JWST) means that we will soon have the capability to characterize the atmospheres of rocky exoplanets. However, it is still unknown whether such planets orbiting close to M dwarf stars…

地球与行星天体物理 · 物理学 2020-01-08 Megan Mansfield , Edwin S. Kite , Renyu Hu , Daniel D. B. Koll , Matej Malik , Jacob L. Bean , Eliza. M. -R. Kempton

Refraction by the atmosphere causes the positions of sources to depend on the airmass through which an observation was taken. This shift is dependent on the underlying spectral energy of the source and the filter or bandpass through which…

天体物理仪器与方法 · 物理学 2019-05-01 Matthias Lee , Tamas Budavari , Ian Sullivan , Andrew Connolly