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相关论文: LOFAR observations of decameter carbon radio recom…

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AIMS: We wish to study the spectral dependence of the radio emission from cosmic-ray air showers around 100 PeV (1017 eV). METHODS: We observe short radio pulses in a broad frequency band with the dipole-interferometer LOPES (LOFAR…

天体物理学 · 物理学 2008-09-17 A. Nigl

Using the latest upper limits on the 21-cm power spectrum at $z\approx9.1$ from the Low Frequency Array (LOFAR), we explore regions of parameter space which are inconsistent with the data. We use 21CMMC, a Monte Carlo Markov Chain sampler…

A radio interferometer uses time delays to maximize its response to radiation coming from a particular direction. These time delays compensate for differences in the time of arrival of the wavefront at the different elements of the…

天体物理仪器与方法 · 物理学 2020-04-08 P. Salas , M. A. Brentjens , D. D. Bordenave , J. B. R. Oonk , H. J. A. Röttgering

We report a radio SETI search for periodic, kHz-wide signals from five of the nearest stars observable with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Using the 19-beam L-band receiver (1.05-1.45 GHz), we obtained…

太阳与恒星天体物理 · 物理学 2026-01-22 Yu Hu , Bo-Lun Huang , Vishal Gajjar , Xiao-Hang Luan , Zhen-Zhao Tao , Tong-Jie Zhang

The carbon to oxygen (C/O) abundance ratio is a valuable tracer of star formation history, as C and O enrichment occurs on different timescales. However, measurements based on ultraviolet (UV) collisionally excited lines and those based on…

We present a survey of atomic carbon (CI) emission in high-redshift (z>2) submillimeter galaxies (SMGs) and quasar host galaxies (QSOs). Sensitive observations of the CI(3P_1->3P_0) and CI(3P_2->3P_1) lines have been obtained at the IRAM…

宇宙学与河外天体物理 · 物理学 2015-05-27 Fabian Walter , Axel Weiss , Dennis Downes , Roberto Decarli , Christian Henkel

We present a spectral line survey of the C-rich envelope CIT 6 in the 2mm and 1.3mm bands carried out with the Arizona Radio Observatory (ARO) 12m telescope and the Heinrich Hertz Submillimeter Telescope (SMT). The observations cover the…

天体物理学 · 物理学 2011-02-11 Yong Zhang , Sun Kwok , Dinh-V-Trung

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…

We present a study of the low-frequency radio properties of star forming (SF) galaxies and active galactic nuclei (AGN) up to redshift $z=2.5$. The new spectral window probed by the Low Frequency Array (LOFAR) allows us to reconstruct the…

Extensive infrared spectra of the weakly-bound CO$_2$-CO dimer are observed in the carbon dioxide $\nu_3$ asymmetric stretch region (~2350 cm-1) using a tunable infrared OPO laser source to probe a pulsed slit jet supersonic expansion. Both…

原子与分子团簇 · 物理学 2021-05-28 A. J. Barclay , A. R. W. McKellar , N. Moazzen-Ahmadi

We report the GMRT detection of associated HI 21 cm-line absorption in the z=1.1946 red quasar 3C 190. Most of the absorption is blue-shifted with respect to the systemic redshift. The absorption, at $\sim$ 647.7 MHz, is broad and complex,…

天体物理学 · 物理学 2009-11-23 C. H. Ishwara-Chandra , K. S. Dwarakanath , K. R. Anantharamaiah

We used the ARO 12m antenna to observe emission from the J=1-0 lines of carbon monoxide, \hcop\ and HNC and the J=2-1 line of CS toward and around the continuum peak used for absorption studies and we compare them with CH, HNC, C\p\ and…

星系天体物理 · 物理学 2016-01-13 Harvey Liszt , Maryvonne Gerin

We have recently used the Faint Images of the Radio Sky at Twenty-centimeters (FIRST) survey to show that red quasars have fundamentally different radio properties to typical blue quasars: a significant (factor $\sim3$) enhancement in the…

We present first results of neutral carbon ([CI], 3P1 - 3P0 at 492 GHz) and carbon monoxide (13CO, J = 1 - 0) mapping in the Vela Molecular Ridge cloud C (VMR-C) and G333 giant molecular cloud complexes with the NANTEN2 and Mopra…

星系天体物理 · 物理学 2015-06-23 N. Lo , M. R. Cunningham , P. A. Jones , L. Bronfman , P. C. Cortes , R. Simon , V. Lowe , L. Fissel , G. Novak

We consider an alternative to conventional three-point statistics such as the bispectrum, which is purely based on the Fourier phases of the density field: the line correlation function. This statistic directly probes the non-linear…

宇宙学与河外天体物理 · 物理学 2017-01-25 Alexander Eggemeier , Robert E. Smith

This paper reports the latest results from a millimeter-wave (CO) spectroscopic survey of IRAS-detected radio galaxies with L_1.4GHz ~ 10^23-28 W/Hz in the redshift range z ~ 0.02-0.15. The IRAS flux-limited sample contains 33 radio…

天体物理学 · 物理学 2009-11-11 A. S. Evans , J. M. Mazzarella , J. A. Surace , D. T. Frayer , K. Iwasawa , D. B. Sanders

Studying the redshifted 21-cm signal from the the neutral hydrogen during the Epoch of Reionization and Cosmic Dawn is fundamental for understanding the physics of the early universe. One of the challenges that 21-cm experiments face is the…

The supernova remnant Cassiopeia A is a prime candidate for accelerating cosmic ray protons and ions. Gamma rays have been observed at GeV and TeV energies, which indicates hadronic interactions, but they could also be caused by…

高能天体物理现象 · 物理学 2011-09-19 A. Summa , D. Elsaesser , K. Mannheim

LOFAR (Low Frequency Array) is an innovative radio telescope optimized for the frequency range 30-240 MHz. The telescope is realized as a phased aperture array without any moving parts. Digital beam forming allows the telescope to point to…