Results 21 to 30 of about 1,260 (183)

Vibrationally Resolved Absorption and Fluorescence Cross Sections of Adamantane in the Far-ultraviolet Spectral Range on an Absolute Scale

The Astrophysical Journal Supplement Series, 2023
High-resolution absorption, dispersed fluorescence emission, and photoionization cross sections are presented for gas-phase adamantane excited by synchrotron radiation in the exciting-photon energy range of 6–30 eV. Relative and absolute absorption cross
Lutz Marder, Alexander Breier, Nelson de Oliveira, Philipp Reiss, Philipp Schmidt, Christian Ozga, Catmarna Küstner-Wetekam, Thomas Giesen, Laurent Nahon, Andreas Hans, André Knie, Arno Ehresmann   +11 more
doaj   +1 more source

Interstellar absorption lines in the spectrum of 3C 273

The Astrophysical Journal, 1983
Absorption lines near the rest wavelengths of the Si IV doublet (wavelengths 1393.76, 1402.77) with equivalent widths 533 and 235 mA are reported in the spectrum of QSO 3C 273. The profiles show the nature of hot gas along a high-latitude (b = 64 deg) line of sight through our entire halo.
D. G. York, C. C. Wu, J. C. Blades, S. Ratcliff, L. L. Cowie, D. C. Morton   +5 more
openaire   +1 more source

Photochemical effects of Mars‐like UV irradiation on carboxylic acids in carbonaceous chondrites and expectations for abiotic background organics on Mars

Meteoritics &Planetary Science, EarlyView.
Abstract In the search for life on Mars, understanding the origin of preserved organics is critical. Expected sources include exogenous delivery, endogenous synthesis, and potentially life. Environmental processing by ultraviolet (UV) irradiation can alter these organics, obscuring hallmarks of their origin. To deconvolve these effects, we conducted an
D. K. Buckner, J. C. Aponte, A. C. Schuerger, D. I. Foustoukos, F. Seguin, M. B. Wilhelm, G. Cooper, A. J. Williams   +7 more
wiley   +1 more source

Interstellar Absorption Lines in the Direction of the Cataclysmic Variable SS Cygni [PDF]

Publications of the Astronomical Society of the Pacific, 2013
We present an analysis of interstellar absorption lines in high-resolution optical echelle spectra of SS Cyg obtained during an outburst in 2013 June and in archival Hubble Space Telescope and Far Ultraviolet Spectroscopic Explorer data. The Ca II K and Na I D lines toward SS Cyg are compared with those toward nearby B and A stars in an effort to place
Ritchey, Adam M., Wallerstein, George, McKeever, Jean   +2 more
openaire   +3 more sources

CLASSY VII Lyα Profiles: The Structure and Kinematics of Neutral Gas and Implications for LyC Escape in Reionization-era Analogs

The Astrophysical Journal, 2023
Ly α line profiles are a powerful probe of interstellar medium (ISM) structure, outflow speed, and Lyman-continuum escape fraction. In this paper, we present the Ly α line profiles of the Cosmic Origins Spectrograph (COS) Legacy Archive Spectroscopic ...
Weida Hu, Crystal L. Martin, Max Gronke, Simon Gazagnes, Matthew Hayes, John Chisholm, Timothy Heckman, Matilde Mingozzi, Namrata Roy, Peter Senchyna, Xinfeng Xu, Danielle A. Berg, Bethan L. James, Daniel P. Stark, Karla Z. Arellano-Córdova, Alaina Henry, Anne E. Jaskot, Nimisha Kumari, Kaelee S. Parker, Claudia Scarlata, Aida Wofford, Ricardo O. Amorín, Naunet Leonhardes-Barboza, Jarle Brinchmann, Cody Carr, Alessandra Aloisi   +25 more
doaj   +1 more source

Regarding the Detection of Interstellar C4 and C5 Molecules

The Astrophysical Journal
Analysis of very high signal-to-noise ratio (S/N) spectra of reddened stars allowed us to determine an upper limit (UL) of the column density N (C _4 ).
G. A. Galazutdinov, E. I. Kazanina, J. Krełowski   +2 more
doaj   +1 more source

Investigating interstellar dust along the line of sight of GX 13+1 using different dust-size distributions

Astronomy & Astrophysics
Context. High-resolution X-ray spectroscopy offers a powerful tool to investigate the physical and chemical properties of dust grains, especially through the analysis of absorption edges of elements such as oxygen, magnesium, silicon, and iron, which are
Vaia B., Zeegers S. T., Abril-Cabezas I., Costantini E.   +3 more
doaj   +1 more source

Chemical Kinetics of 2‐, 4‐, and 2,4‐Seleno‐Uracils at Low Temperatures: Tautomerizations and Rotamerizations on Inert Matrices

International Journal of Chemical Kinetics, Volume 58, Issue 10, Page 881-889, October 2026.
ABSTRACT In the interstellar medium, chemical reactions proceed under conditions vastly different to those on Earth; these include extremely low temperatures and densities and take place in the gas phase and on water–ice grains. Understanding the energetics and more importantly the kinetics of such reactions is of relevance to the consequences on how ...
Judith Wurmel, John M. Simmie
wiley   +1 more source

Mapping Our Path through the Local Interstellar Medium: High-resolution Ultraviolet Absorption Spectroscopy of Sight Lines along the Sun’s Historical Trajectory

The Astrophysical Journal
Using high-resolution UV data obtained from the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, we focus on eight sight lines along the Sun’s historical trajectory to reconstruct the morphology of our most recent interstellar ...
Hunter Vannier, Seth Redfield, Brian E. Wood, Hans-Reinhard Müller, Jeffrey L. Linsky, Priscilla C. Frisch   +5 more
doaj   +1 more source

Interstellar absorption lines in the galaxy NGC 1705

The Astrophysical Journal, 1990
The possibility is considered, and shown to be plausible, that the strong C IV and Si IV absorption lines in low-resolution ultraviolet spectra of gas-rich dwarf galaxies are primarily interstellar, not stellar as has been supposed. The argument is based on analogies with H II regions in the Local Group, on low-resolution equivalent width measurements ...
D. G. York, A. Caulet, P. Rybski, J. Gallagher, J. C. Blades, D. C. Morton, W. Wamsteker   +6 more
openaire   +1 more source