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Related papers: Re-evaluation of the cosmic-ray ionization rate in…

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In the interstellar medium, cosmic rays (CRs) generate a field of ultraviolet (UV) photons via the excitation and subsequent radiative decay of $\rm H_2$ molecules. This UV field is a major agent of ionization and dissociation in the inner…

Astrophysics of Galaxies · Physics 2026-01-15 O. Sipilä , P. Caselli , M. Padovani , D. Galli , T. Grassi , H. R. Hrodmarsson , S. S. Jensen , E. Roueff

Context: It has been proposed that H$_2$ near-infrared lines may be excited by cosmic rays and allow for a determination of the cosmic-ray ionization rate in dense gas. One-dimensional models show that measuring both the H$_2$ gas column…

Astrophysics of Galaxies · Physics 2022-08-24 Brandt A. L. Gaches , Shmuel Bialy , Thomas G. Bisbas , Marco Padovani , Daniel Seifried , Stefanie Walch

We present new three-dimensional (3D) interstellar extinction maps in the $V$ and Gaia $G$ filters within 2 kpc of the Sun, a 3D differential extinction (dust spatial distribution density) map along the lines of sight in the same space, a…

Carbon monoxide (CO) is a poor tracer of H$_{2}$ in the diffuse interstellar medium (ISM), where most of the carbon is not incorporated into CO molecules unlike the situation at higher extinctions. We present a novel, indirect method to…

Astrophysics of Galaxies · Physics 2023-12-18 Raphael Skalidis , Paul F. Goldsmith , Philip F. Hopkins , Sam B. Ponnada

We present a new 3D map of interstellar dust reddening, covering three quarters of the sky (declinations greater than -30 degrees) out to a distance of several kiloparsecs. The map is based on high-quality stellar photometry of 800 million…

We report the first ensemble results from the FUSE survey of molecular hydrogen in lines of sight with A_V $\gtrsim$ 1 mag. We have developed techniques for fitting computed profiles to the low-J lines of H2, and thus determining column…

We present an extinction analysis of 9 paths through the LMC and SMC based on FUSE observations. To date, just two LMC sight lines have probed dust grain composition and size distributions in the Clouds using spectra including wavelengths…

We present optical depth and temperature maps of the Perseus molecular cloud, obtained combining dust emission data from the Herschel and Planck satellites and 2MASS/NIR dust extinction maps. The maps have a resolution of 36 arcsec in the…

Solar and Stellar Astrophysics · Physics 2016-03-02 E. Zari , M. Lombardi , J. Alves , C. J. Lada , H. Bouy

Photometric redshifts can be routinely obtained to accuracies of better than 0.1 in Delta(z)/(1+z). However, the issue of dust extinction is one that has still not been well quantified. In this paper the success of two template-fitting…

Astrophysics · Physics 2007-05-23 T. S. R Babbedge , R. Whitaker , S. Morris

A proper modelling of the cosmic-ray ionisation rate within gas clouds is crucial to describe their chemical evolution accurately. However, this modelling is computationally demanding because it requires the propagation of cosmic rays…

Astrophysics of Galaxies · Physics 2025-07-08 G. Latrille , A. Lupi , S. Bovino , T. Grassi , G. Sabatini , M. Padovani

We aim to compare variations in the full-UV dust extinction curve (912-3000 Angstrom), with the HI/H$_2$/total H content along diffuse Milky Way sightlines, to investigate possible connections between ISM conditions and dust properties. We…

Astrophysics of Galaxies · Physics 2023-02-15 Dries Van De Putte , Stefan I. B. Cartledge , Karl D. Gordon , Geoffrey C. Clayton , Julia Roman-Duval

Galactic cosmic rays are a ubiquitous source of ionisation of the interstellar gas, competing with UV and X-ray photons as well as natural radioactivity in determining the fractional abundance of electrons, ions and charged dust grains in…

High Energy Astrophysical Phenomena · Physics 2018-06-27 Marco Padovani , Alexei V. Ivlev , Daniele Galli , Paola Caselli

We have constructed three-dimensional models for the equilibrium abundance of molecular hydrogen within diffuse interstellar clouds of arbitrary geometry that are illuminated by ultraviolet radiation. The position-dependent photo-…

Astrophysics · Physics 2009-10-30 Marco Spaans , David A. Neufeld

Cosmic rays are an essential ingredient in the evolution of the interstellar medium, as they dominate the ionisation of the dense molecular gas, where stars and planets form. However, since they are efficiently scattered by the galactic…

Astrophysics of Galaxies · Physics 2014-09-05 Solenn Vaupré , Pierre Hily-Blant , Cecilia Ceccarelli , Guillaume Dubus , Stefano Gabici , Thierry Montmerle

We present three-dimensional astrochemical simulations and synthetic observations of magnetised, turbulent, self-gravitating molecular clouds. We explore various galactic interstellar medium environments, including cosmic-ray ionization…

Astrophysics of Galaxies · Physics 2021-01-20 Thomas G. Bisbas , Jonathan C. Tan , Kei E. I. Tanaka

We model the interstellar dust content of the reionization era with a suite of cosmological, fluid-dynamical simulations of galaxies with stellar masses ranging from $\sim 10^5 - 10^9 M_{\odot}$ in the first $1.2$ billion years of the…

Astrophysics of Galaxies · Physics 2023-08-24 Clarke J. Esmerian , Nickolay Y. Gnedin

Tracing dust in small dense molecular cores is a powerful tool to study the conditions required for ices to form during the pre-stellar phase. To study these environments, five molecular cores were observed: three with ongoing low-mass star…

Astrophysics of Galaxies · Physics 2021-09-08 Laurie E. U. Chu , Klaus W. Hodapp

3D tomography of the interstellar dust and gas may be useful in many respects, from the physical and chemical evolution of the ISM itself to foreground decontamination of the CMB, or various studies of the environments of specific objects.…

Astrophysics of Galaxies · Physics 2015-05-18 Jean-Luc Vergely , Bernard Valette , Rosine Lallement , Severine Raimond

New low-resolution UV spectra of a sample of reddened OB stars in M31 were obtained with HST/STIS to study the wavelength dependence of interstellar extinction and the nature of the underlying dust grain populations. Extinction curves were…

We present a new dust extinction technique with which we are able to retrieve parsec-scale gas surface density maps for entire nearby galaxies. The method measures the dust attenuation in optical bands on a pixel-by-pixel basis against a…