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We describe the design, construction, and characterization of the Band 9 heterodyne receivers (600-720 GHz) for the Atacama Large Millimeter / submillimeter Array (ALMA). The ALMA Band 9 receiver units ("cartridges"), which are installed in…

We investigate the correlations between the observed fraction of Lyman alpha emission from star-forming galaxies and the large scale structure by post-processing snapshots of a large, high resolution hydrodynamical simulation with a Lyman…

宇宙学与河外天体物理 · 物理学 2013-07-23 Christoph Behrens , Jens Niemeyer

(abridged) Radio recombination lines (RRLs) at frequencies $\nu$ < 250 MHz trace the cold, diffuse phase of the ISM. Next generation low frequency interferometers, such as LOFAR, MWA and the future SKA, with unprecedented sensitivity,…

天体物理仪器与方法 · 物理学 2020-02-26 K. L. Emig , P. Salas , F. de Gasperin , J. B. R. Oonk , M. C. Toribio , A. P. Mechev , H. J. A. Rottgering , A. G. G. M. Tielens

At intermediate to high densities, electron (de-)excitation collisions are the dominant process for populating or depopulating high Rydberg states. In particular, the accurate knowledge of the energy changing ($n$-changing) collisional…

星系天体物理 · 物理学 2019-04-10 F. Guzmán , M. Chatzikos , P. A. M. van Hoof , Dana S. Balser , M. Dehghanian , N. R. Badnell , G. J. Ferland

We have started a long-term reverberation mapping project using the Wyoming Infrared Observatory 2.3 meter telescope titled "Monitoring AGNs with H\beta\ Asymmetry" (MAHA). The motivations of the project are to explore the geometry and…

The Aim of our study is to understand the variety of observed Lyman-alpha (Lya) line profiles and strengths in Lyman Break Galaxies (LBGs) and Lya emitters (LAEs), the physical parameters governing them, and hence deriving constraints on…

天体物理学 · 物理学 2009-11-13 Anne Verhamme , Daniel Schaerer , Hakim Atek , Christian Tapken

We present a multiple emission lines study of $\sim$1300 H$\alpha$ emitters (HAEs) at $z \sim 2.3$ in the ZFOURGE survey. In contrast to the traditional spectroscopic method, our sample is selected based on the flux excess in the…

In 2017, an Atacama Large Millimeter/submillimeter Array (ALMA) high-frequency long baseline campaign was organized to test image capabilities with baselines up to 16 km at submillimeter (submm) wavelengths. We investigated image qualities…

We present a detailed analysis of the spatially and spectrally resolved 12CO J=2-1 and J=3-2 emission lines from the TW Hya circumstellar disk, based on science verification data from the Atacama Large Millimeter/Submillimeter Array (ALMA).…

We investigate the effects of horizontal radiative transfer (RT) a NLTE on important diagnostic iron lines in a realistic 3-D HD simulation. Using a multi-level atom we compute and compare widely used Fe I line profiles at 3 different…

太阳与恒星天体物理 · 物理学 2015-06-16 R. Holzreuter , S. K. Solanki

Aims: A pilot project has been carried out to measure circumstellar CO emission from three OH/IR stars close to the Galactic centre. The intention was to find out whether it would be possible to conduct a large-scale survey for mass-loss…

星系天体物理 · 物理学 2009-11-13 A. Winnberg , S. Deguchi , M. J. Reid , J. Nakashima , H. Olofsson , H. J. Habing

In the past few years, the ALMA radio telescope has become available for solar observations. ALMA diagnostics of the solar atmosphere are of high interest because of the theoretically expected linear relationship between the brightness…

太阳与恒星天体物理 · 物理学 2020-04-08 Juan Martinez-Sykora , Bart De Pontieu , Jaime de la Cruz Rodriguez , Georgios Chintzoglou

The velocity profiles of weak metal absorption lines can be used to observationally probe the kinematic state of gas in damped Lyman-alpha systems. Prochaska and Wolfe have argued that the flat distribution of velocity widths combined with…

天体物理学 · 物理学 2009-10-31 Ariyeh H. Maller , Rachel S. Somerville , Jason X. Prochaska , Joel R. Primack

We present a new three-dimensional radiative transfer (RT) code, RADAMESH, based on a ray-tracing, photon-conserving and adaptive (in space and time) scheme. RADAMESH uses a novel Monte Carlo approach to sample the radiation field within…

宇宙学与河外天体物理 · 物理学 2015-05-19 Sebastiano Cantalupo , Cristiano Porciani

We present a Radio Recombination Line (RRL) survey of the Galactic Plane from the HI Parkes All-sky Survey and associated Zone of Avoidance survey, which mapped the region l=196degr -- 0degr --52degr and |b| < 5degr at 1.4 GHz and 14.4…

We present images of $\eta$ Carinae in the recombination lines H30$\alpha$ and He30$\alpha$ and the underlying continuum with 50~mas resolution (110 AU), obtained with ALMA. For the first time, the 230 GHz continuum image is resolved into a…

太阳与恒星天体物理 · 物理学 2020-09-30 Z. Abraham , P. P. B. Beaklini , P. Cox , L-Å. Nyman , D. Falceta-Gonçalves

Recently, \citet{Nicholls12}, inspired by \emph{in situ} observations of solar system astrophysical plasmas, suggested that the electrons in \HII regions are characterised by a $\kappa$-distribution of electron energies rather than by a…

宇宙学与河外天体物理 · 物理学 2015-06-16 Michael A. Dopita , Ralph S. Sutherland , David C. Nicholls , Lisa J. Kewley , Frédéric P. A. Vogt

Recent work has shown that UV-luminous reionization-era galaxies often exhibit strong Lyman-alpha emission despite being situated at redshifts where the IGM is thought to be substantially neutral. It has been argued that this enhanced…

We discuss the detection of redshifted line and continuum emission at radio wavelengths using a Square Kilometer Array (SKA), specifically from low-excitation rotational molecular line transitions of CO and HCN (molecular lines), the…

天体物理学 · 物理学 2009-11-10 Andrew W. Blain , C. L. Carilli , Jeremy Darling

The importance of the Atacama Large Millimeter Array (ALMA) to the study of high-redshift dusty gas-rich galaxies is described. ALMA will have dramatically greater sensitivity and angular resolution than existing millimetre(mm) and…

天体物理学 · 物理学 2007-05-23 Andrew W. Blain