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Related papers: The Electron Temperature Gradient in the Galactic …

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We present a high spatial resolution map of the columnar electron temperature (Tc) of a region to the south west of the Trapezium in the Orion Nebula. This map was derived from Hubble Space Telescope images that isolated the primary lines…

Astrophysics · Physics 2009-11-07 C. R. O'Dell , M. Peimbert , A. Peimbert

The rest-frame UV spectra of star-forming galaxies are increasingly important as they become one of the primary windows to probe the physical properties of cosmic dawn (z>8) galaxies with the James Webb Space Telescope. However, the…

The problem of determination of the electron temperature t_2 in the OII zone of high-metallicity HII region was examined. It was shown that the ratio of nebular to auroral nitrogen line intensities, which is an indicator of the electron…

Astrophysics · Physics 2008-11-26 L. S. Pilyugin

Using G dwarfs from the Sloan Extension for Galactic Understanding and Exploration (SEGUE) survey, we have determined a vertical metallicity gradient over a large volume of the Milky Way's disk, and examined how this gradient varies for…

Open clusters offer a unique possibility to study the time evolution of the radial metallicity gradients of several elements in our Galaxy, because they span large intervals in age and Galactocentric distance, and both quantities can be…

Astrophysics · Physics 2009-11-13 Laura Magrini , Paola Sestito , Sofia Randich , Daniele Galli

The diffuse high-energy gamma-ray emission of the Milky Way arises from interactions of cosmic-rays (CRs) with interstellar gas and radiation field in the Galaxy. The neutral hydrogen (H I) gas component is by far the most massive and…

High Energy Astrophysical Phenomena · Physics 2019-08-13 Gudlaugur Johannesson , Igor Moskalenko , Seth Digel

We present a study of the filamentary structure in the atomic hydrogen (HI) emission at the 21 cm wavelength toward the Galactic plane using the observations in the HI4PI survey. Using the Hessian matrix method across radial velocity…

The temperatures of interstellar dust grains are analyzed using stochastic simulations, taking into account the grain composition and size and the discreteness of the photon flux. [...] The distribution of grain temperatures is calculated…

Astrophysics · Physics 2007-09-21 Kobi Horn , Hagai B. Perets , Ofer Biham

We report a new, reliable determination of the CN excitation temperature of diffuse molecular clouds in the Milky Way, based on ultra high spectral resolution observations. Our determination is based on CN $B^{2}\Sigma^{+}-X^{2}\Sigma^{+}$…

Astrophysics of Galaxies · Physics 2024-12-09 Ryan J. Cooke , Louise Welsh

The Central Molecular Zone (CMZ) at the center of our Galaxy is the best template to study star formation processes under extreme conditions, similar to those in high-redshift galaxies. We observed on-the-fly maps of para-H$_{2}$CO…

Astrophysics of Galaxies · Physics 2016-11-09 K. Immer , J. Kauffmann , T. Pillai , A. Ginsburg , K. M. Menten

Atomic Hydrogen-21 cm transition (HI) is an excellent tracer to study and understand the properties of the atomic gas in the Galaxy. Using the Westerbork Synthesis Radio Telescope (WSRT), we observed 12 quasar sightlines to detect galactic…

Astrophysics of Galaxies · Physics 2024-03-19 Narendra Nath Patra , Nirupam Roy

Using data from the LAMOST Medium-Resolution Spectroscopic Survey of Nebulae, we create a sample of 17,821 diffuse ionized gas (DIG) spectra in the anti-center region of the Milky Way, by excluding fibers in the directions of H II regions…

Cosmic-ray and X-ray heating are derived from the electron energy loss calculations of Dalgarno, Yan and Liu for hydrogen-helium gas mixtures. These authors treated the heating from elastic scattering and collisional de-excitation of…

Astrophysics of Galaxies · Physics 2015-06-11 Alfred E. Glassgold , Daniele Galli , Marco Padovani

The observed radial and vertical metallicity distribution of old stars in the Milky Way disk provides a powerful constraint on the chemical enrichment and dynamical history of the disk. We present the radial metallicity gradient,…

Synchrotron emission pervades the Galactic plane at low radio frequencies, originating from cosmic ray electrons interacting with the Galactic magnetic field. Using a low-frequency radio telescope, the Murchison Widefield Array (MWA), we…

The structure, formation, and evolution of the Milky Way bulge is a matter of debate. Important diagnostics for discriminating between bulge models include alpha-abundance trends with metallicity, and spatial abundance and metallicity…

Astrophysics of Galaxies · Physics 2015-12-23 N. Ryde , M. Schultheis , V. Grieco , F. Matteucci , R. M. Rich , S. Uttenthaler

We examine far-infrared and submillimeter spectral energy distributions for galaxies in the Infrared Space Observatory Atlas of Bright Spiral Galaxies. For the 71 galaxies where we had complete 60-180 micron data, we fit blackbodies with…

We have carried out deep, high velocity resolution, interferometric Galactic HI 21 cm absorption spectroscopy towards 32 compact extra-galactic radio sources with the Giant Metrewave Radio Telescope (GMRT) and the Westerbork Synthesis Radio…

Astrophysics of Galaxies · Physics 2014-07-30 Nirupam Roy , Nissim Kanekar , Robert Braun , Jayaram N. Chengalur

While uniform temperature has no effect on equilibrium properties of hard-core systems, its gradient might substantially change their behaviour. In particular, in hard-disk system subject to temperature difference $\Delta T$ disks are…

Statistical Mechanics · Physics 2015-05-18 Sebastian Woloszczuk , Adam Lipowski

We calculate the effective temperature ($T_{\rm eff}$) of ionizing star(s), oxygen abundance of the gas phase $(\rm O/H)$, and the ionization parameter $U$ for a sample of H\,{\sc ii} regions located in the disks of 59 spiral galaxies in…

Astrophysics of Galaxies · Physics 2018-12-19 I. A. Zinchenko , O. L. Dors , G. F. Hagele , M. V. Cardaci , A. C. Krabbe