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Related papers: Calcium H & K Induced by Galaxy Halos

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Many of the baryons in our Galaxy probably lie outside the well known disk and bulge components. Despite a wealth of evidence for the presence of some gas in galactic halos, including absorption line systems in the spectra of quasars, high…

Astrophysics of Galaxies · Physics 2017-04-10 Huanian Zhang , Dennis Zaritsky

We explore the behaviour of [CII]-157.74um forbidden fine-structure line observed in a sample of 28 galaxies selected from ~50deg^2 of the H-ATLAS survey. The sample is restricted to galaxies with flux densities higher than S_160um>150mJy…

Newly-computed collisional rate coefficients for the excitation of C$_2$ in collisions with H$_2$, presented recently by Najar and Kalugina (2020), are significantly larger than the values adopted previously in models for the excitation of…

At present, all physical models of diffuse Galactic gamma-ray emission assume that the distribution of cosmic-ray sources traces the observed populations of either OB stars, pulsars, or supernova remnants. However, since H2-rich regions…

High Energy Astrophysical Phenomena · Physics 2016-09-14 Eric Carlson , Tim Linden , Stefano Profumo

We present results from the Keck Baryonic Structure Survey (KBSS), a unique spectroscopic survey designed to explore the connection between galaxies and intergalactic baryons. The KBSS is optimized for the redshift range z ~ 2-3, combining…

We describe a moderate-resolution FUSE survey of H2 along 70 sight lines to the Small and Large Magellanic Clouds, using hot stars as background sources. FUSE spectra of 67% of observed Magellanic Cloud sources (52% of LMC and 92% of SMC)…

The main chromospheric activity indicator is the S index, which is esentially the ratio of the flux in the core of the Ca II H and K lines to the continuum nearby, and is well studied basically for stars from F to K. Another usual…

Astrophysics · Physics 2008-11-26 Carolina Cincunegui , Rodrigo F. Díaz , Pablo J. D. Mauas

We characterize the physical properties of the cool T ~10^4 K circumgalactic medium surrounding z ~2-3 quasar host galaxies, which are predicted to evolve into present day massive ellipticals. Using a statistical sample of 14 quasar pairs…

Astrophysics of Galaxies · Physics 2016-10-26 Marie Wingyee Lau , J. Xavier Prochaska , Joseph F. Hennawi

We perform a systematic study of physical properties and distribution of neutral and ionised gas in the halo of the Milky Way (MW). Beside the large neutral intermediate- and high-velocity cloud (IVC, HVC) complexes there exists a…

Astrophysics of Galaxies · Physics 2010-07-21 N. Ben Bekhti , P. Richter , B. Winkel , J. Kerp , P. Kalberla , U. Klein , M. T. Murphy

Lyman- and Werner-band absorption of molecular hydrogen (H$_2$) is detected in $\sim$50% of low redshift ($z<1$) DLAs/sub-DLAs with $N$(H$_2$) > 10$^{14.4}$ cm$^{-2}$. However the true origin(s) of the H$_2$ bearing gas remain elusive. Here…

Astrophysics of Galaxies · Physics 2016-06-01 Sowgat Muzahid , Glenn G. Kacprzak , Jane C. Charlton , Christopher W. Churchill

We report the discovery of a rare Mg II $\lambda$$\lambda$ 2796, 2803 doublet emission halo around a star forming galaxy with $\log (M_\star$/M$_\odot) = 10.3 \pm 0.3$ at $z=0.737$ in deep (9.94 h) VLT/MUSE data from the MUSE-HUDF mosaic.…

We explore the circumgalactic metal content traced by commonly observed low ion absorbers, including C II, Si II, Si III, Si IV, and Mg II. We use a set of cosmological hydrodynamical zoom simulations run with the EAGLE model and including…

Astrophysics of Galaxies · Physics 2018-08-29 Benjamin D. Oppenheimer , Joop Schaye , Robert A. Crain , Jessica K. Werk , Alexander J. Richings

The circumgalactic medium (CGM) serves as a baryon reservoir that connects galaxies to the intergalactic medium and fuels star formation. The spatial distribution of the metal-enriched cool CGM has not yet been directly revealed at cosmic…

We study the contribution of galaxies with different properties to the global densities of star formation rate (SFR), atomic (HI) and molecular hydrogen (H2) as a function of redshift. We use the GALFORM model of galaxy formation, which is…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Claudia del P. Lagos , C. M. Baugh , M. A. Zwaan , C. G. Lacey , V. Gonzalez-Perez , C. Power , A. M. Swinbank , E. van Kampen

Galaxies can form in a sufficiently deep gravitational potential so that efficient gas cooling occurs. We estimate that such potential is provided by a halo of mass $M \gtsim M_{c} \approx 7.0 \times 10^{12} ~ (\Delta_{c}(z)…

Astrophysics · Physics 2009-09-07 Hung-Yu Jian , Chia-Hung Chien , Tzihong Chiueh

Physical conditions within DLAs can reveal the star formation history, determine the chemical composition of the associated ISM, and hence document the first steps in the formation of present day galaxies. Here we present calculations that…

Astrophysics · Physics 2009-09-29 Raghunathan Srianand , Gargi Shaw , Gary Ferland , Patrick Petitjean , Cedric Ledoux

Low-metallicity dwarf galaxies often show no or little CO emission, despite the intense star formation observed in local samples. Both simulations and resolved observations indicate that molecular gas in low-metallicity galaxies may reside…

We present a census of neutral gas in the Milky Way disk and halo down to limiting column densities of $N$(HI)$\sim10^{14}$ cm$^{-2}$ using measurements of HI Lyman-series absorption from the Far Ultraviolet Spectroscopic Explorer (FUSE).…

Because the 157.74 micron [C II] line is the dominant coolant of star-forming regions, it is often used to infer the global star-formation rates of galaxies. By characterizing the [C II] and far-infrared emission from nearby Galactic…