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200 papers

Based on measurements with the Effelsberg 100-m telescope, a multi-line study of molecular species is presented toward the south-western source of the gravitational lens system PKS 1830-211, which is by far the best known target to study…

Astrophysics of Galaxies · Physics 2015-02-04 A. Schulz , C. Henkel , K. M. Menten , S. Muller , D. Muders , J. Bagdonaite , W. Ubachs

Combining our own observations with data from the literature, we consider the incidence of HI absorption in Gigahertz Peaked Spectrum (GPS) and Compact Steep Spectrum (CSS) sources. Here we present our preliminary results, where we find…

Astrophysics · Physics 2009-11-07 Y. M. Pihlstroem , J. E. Conway , R. C. Vermeulen

The interstellar medium (ISM) has a number of tracers such as the Na I D 5890, 5896 AA absorption lines that are evident in the spectra of galaxies but also in those of individual astrophysical sources such as stars, novae or quasars. Here,…

Despite much searching, redshifted decimetre and millimetre-band absorption by molecular gas remains very rare, limited to just six systems at z > 0.05. Detection of these transitions can yield precise diagnostics of the conditions of the…

Astrophysics of Galaxies · Physics 2021-10-04 S. J. Curran

We build HI absorption spectra towards Supernova Remnant (SNRs) G16.7+0.1 and G15.9+0.2 using the THOR survey data. With the absorption spectra, we give a new distance range of 7 to 16 kpc for G15.9+0.2. We also resolve the near/far-side…

Astrophysics of Galaxies · Physics 2019-09-25 W. W. Tian , H. Zhu , M. F. Zhang , H. K. Chang , S. S. Shan , D. A. Leahy

This paper presents data from the BIMA interferometer showing spatially resolved absorption spectra of the gravitationally lensed quasar PKS 1830-211. High-resolution (1.2 km/s) spectra were taken in two spectral windows centered on the…

Astrophysics · Physics 2009-11-06 J. Swift , W. J. Welch , B. Frye

We present the first results of an ALMA spectral survey of strong absorption lines for common interstellar species in the z=0.89 molecular absorber toward the lensed blazar PKS1830-211. The dataset brings essential information on the…

With the Plateau de Bure interferometer, we have measured the C, N, O and S isotopic abundance ratios in the arm of a spiral galaxy with a redshift of 0.89. The galaxy is seen face-on according to HST images. Its bulge intercepts the line…

Astrophysics · Physics 2009-11-11 Sebastien Muller , Michel Guelin , Michael Dumke , Robert Lucas , Francoise Combes

We report on WSRT observations of HI and OH absorption at z=0.885 towards the radio lens PKS 1830-21, mm wave transitions of several molecular species have already been observed at this redshift. At mm wavelengths the source structure is…

Astrophysics · Physics 2011-05-23 Jayaram N. Chengalur , A. G. de Bruyn , D. Narasimha

High-mass gamma-ray binaries consist of a presumptive pulsar in orbit with a massive star. The intense outflows from the star can absorb radio emission from the pulsar, making the detection of pulsation difficult. In this work, we present…

High Energy Astrophysical Phenomena · Physics 2021-08-11 A. M. Chen , Y. D. Guo , Y. W. Yu , J. Takata

This paper analyzes the 53.3um line in the ISO LWS spectra towards a similar sample of OH/IR sources. We find 137 LWS spectra covering 53.3um and associated with 47 galactic OH/IR sources. Ten of these galactic OH/IR sources are found to…

Astrophysics · Physics 2007-05-23 J. H. He , P. S. Chen

We present photoionization models accounting for both photoelectric and resonant absorption. Resonance absorption lines from C, O, Ne, Mg, Si S and Fe between 0.1 and 10 keV are treated. In particular we consider the complex of almost 60…

Astrophysics · Physics 2009-10-31 Fabrizio Nicastro , Fabrizio Fiore , Giorgio Matt

The BL Lac PKS 1413+135 was observed by the Large Survey Project "MeerKAT Absorption Line Survey" (MALS) in the L-band, at 1139 MHz and 1293-1379 MHz, targeting the HI and OH lines in absorption at z = 0.24671. The radio continuum is…

While the small sticking coefficient for molecular hydrogen on the Si(001) surface apparently requires a large energy barrier of adsorption, no such barrier is observed in desorption experiments. We have calculated the potential-energy…

mtrl-th · Physics 2009-10-28 E. Pehlke , M. Scheffler

The interstellar hydride hydroxyl (OH) is a potential tracer of CO-dark molecular gas. We present new absorption line observations of OH at 18-cm wavelength towards four continuum sources. We compare these to the [CII] line at 1.9 THz…

We report on a survey for associated HI 21-cm and OH 18-cm absorption with the Giant Metrewave Radio Telescope at redshifts z = 0.2-0.4. Although the low redshift selection ensures that our targets are below the critical ultra-violet…

Astrophysics of Galaxies · Physics 2017-03-29 S. J. Curran , M. T. Whiting , J. R. Allison , A. Tanna E. M. Sadler , R. Athreya

We present preliminary results from the recent multi-epoch HI absorption measurements toward several pulsars using the Arecibo telescope. We do not find significant variations in optical depth profiles over periods of 4 months and 9 years.…

Astrophysics · Physics 2009-11-10 S. Stanimirovic , J. M. Weisberg , A. Hedden , K. Devine , T. Greent , S. B. Anderson

The dependence of the turnover frequency on the linear size is presented for a sample of GPS and CSS radio sources derived from complete samples. The dependence of the luminosity of the emission at the peak frequency with the linear size…

Astrophysics of Galaxies · Physics 2016-04-20 Solai Jeyakumar

Existing studies of the atomic hydrogen gas content in distant galaxies, through the absorption of the 21-cm line, often infer that the total column density is anti-correlated with the linear extent of the background radio source. We…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 S. J. Curran , J. R. Allison , M. Glowacki , M. T. Whiting , E. M. Sadler

Absorption spectra of small molecular aggregates (oligomers) are considered. The dipole-dipole interaction between the monomers leads to shifts of the oligomer spectra with respect to the monomer absorption. The line-shapes of monomer as…

Chemical Physics · Physics 2011-02-03 Jan Roden , Walter T. Strunz , Alexander Eisfeld