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We report multi-frequency Very Large Array observations of three massive star formation regions (MSFRs) containing radio continuum components that were identified as broad radio recombination line (RRL) sources and hypercompact (HC) H II…

星系天体物理 · 物理学 2015-05-28 M. Sewilo , E. Churchwell , S. Kurtz , W. M. Goss , P. Hofner

Carbon radio recombination lines (RRLs) at low frequencies (<=500 MHz) trace the cold, diffuse phase of the interstellar medium, which is otherwise difficult to observe. We present the detection of carbon RRLs in absorption in M82 with…

Interstellar molecules are excellent tools for studying the physical and chemical environments of massive star-forming regions. In particular, vibrationally excited HC$_3$N (HC$_3$N*) lines are the key tracers for probing hot cores…

We use the Low Frequency Array to perform a systematic high spectral resolution investigation of the low-frequency 33-78 MHz spectrum along the line of sight to Cassiopeia A. We complement this with a 304-386 MHz Westerbork Synthesis Radio…

An international consortium is presently constructing a beamformer for the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile that will be available as a facility instrument. The beamformer will aggregate the entire collecting…

In dense hot star winds, the infrared and radio continua are dominated by free-free opacity and recombination emission line spectra. In the case of a spherically symmetric outflow that is isothermal and expanding at constant radial speed,…

天体物理学 · 物理学 2015-05-13 Richard Ignace

We have performed a multi-species hydrodynamical simulation of the formation and evolution of Lyman alpha clouds in a flat CDM dominated universe with an external flux of ionizing radiation. We solve the fully coupled non-equilibrium rate…

天体物理学 · 物理学 2009-10-28 Yu Zhang , Peter Anninos , Michael L. Norman

Spectral observations below Lyman-alpha are now obtained with the Cosmic Origin Spectrograph (COS) on the Hubble Space Telescope (HST). It is therefore necessary to provide an accurate treatment of the blue wing of the Lyman-alpha line that…

太阳与恒星天体物理 · 物理学 2021-07-21 F. Spiegelman , N. F. Allard , J. F. Kielkopf

The Atacama Large Millimeter/sub-millimeter Array (ALMA) is already revolutionising our understanding of the Universe. However, ALMA is not yet equipped with all of its originally planned receiver bands, which will allow it to observe over…

We have detected the radio recombination lines H91-alpha and H92-alpha with rest frequencies of 8.6 GHz and 8.3 GHz from the starburst nucleus NGC 3256 at an angular resolution of 16.4" x 9.6" using the Australia Telescope Compact Array and…

天体物理学 · 物理学 2009-11-10 A. L. Roy , W. M. Goss , Niruj R. Mohan , K. R. Anantharamaiah

We present the results of ALMA band-5 (~170 GHz) observations of the merging ultraluminous infrared galaxy, the "Superantennae" (IRAS 19254-7245) at z=0.0617, which has been diagnosed as containing a luminous obscured active galactic…

星系天体物理 · 物理学 2021-02-03 Masatoshi Imanishi , Yoshiaki Hagiwara , Shinji Horiuchi , Takuma Izumi , Kouichiro Nakanishi

We investigate the prospects of blind and targeted searches in the radio domain (10 MHz to 1 THz) for high-n hydrogen recombination lines from the first generation of galaxies, at z < 10. The expected optically thin spontaneous alpha-line…

宇宙学与河外天体物理 · 物理学 2015-06-17 Evan Rule , Abraham Loeb , Vladimir Strelnitski

In this paper we consider the effects of resonance and electron scattering on the escape of Lyman alpha photons during cosmological hydrogen recombination. We pay particular attention to the influence of atomic recoil, Doppler boosting and…

宇宙学与河外天体物理 · 物理学 2015-05-13 J. Chluba , R. A. Sunyaev

The resonantly scattered Lyman-$\alpha$ line illuminates the extended halos of neutral hydrogen in the circumgalactic medium of galaxies. We present integral field Keck Cosmic Web Imager observations of double-peaked, spatially extended…

We present a Deep-Learning (DL) pipeline developed for the detection and characterization of astronomical sources within simulated Atacama Large Millimeter/submillimeter Array (ALMA) data cubes. The pipeline is composed of six DL models: a…

天体物理仪器与方法 · 物理学 2022-11-22 Michele Delli Veneri , Lukasz Tychoniec , Fabrizia Guglielmetti , Giuseppe Longo , Eric Villard

We present a systematic study of the intensity mapping technique using updated models for the different emission lines from galaxies and identify which ones are more promising for cosmological studies of the post reionization epoch. We…

宇宙学与河外天体物理 · 物理学 2017-05-25 José Fonseca , Marta B. Silva , Mário G. Santos , Asantha Cooray

Orion KL has served as a benchmark for spectral line searches throughout the (sub)millimeter regime. The main goal is to systematically study spectral characteristics of Orion KL in the 1.3 cm band. We carried out a spectral line survey…

星系天体物理 · 物理学 2015-09-03 Y. Gong , C. Henkel , S. Thorwirth , S. Spezzano , K. M. Menten , C. M. Walmsley , F. Wyrowski , R. Q. Mao , B. Klein

We compute the molecular line emission of massive protostellar disks by solving the equation of radiative transfer through the cores and disks produced by the recent radiation-hydrodynamic simulations of Krumholz, Klein, & McKee. We find…

天体物理学 · 物理学 2009-06-23 Mark R. Krumholz , Richard I. Klein , Christopher F. McKee

Radiative transfer in hydrogen lines in supernova remnant (SNR) shock waves is studied taking into account the population of the hydrogen atom 2s-state. Measurements of Balmer line emission, especially of H~$\alpha$, are often relied upon…

高能天体物理现象 · 物理学 2019-03-27 Jiro Shimoda , J. Martin Laming

Recombination lines involving high principal quantum numbers populate the radio spectrum in large numbers. Low-frequency (<1 GHz) observations of radio recombination lines (RRLs) primarily from carbon and hydrogen offer a new, if not…