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Related papers: The Search for Intergalactic Hydrogen Clouds in Vo…

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We study void galaxies in the TNG300 simulation between redshifts $z=3$ and $z=0$. Cosmic void catalogs were constructed using a watershed-based void-finding algorithm, and we define four populations of field galaxies for our investigation:…

Astrophysics of Galaxies · Physics 2025-12-18 Olivia Curtis , Bryanne McDonough , Tereasa Brainerd

We have carried out a sensitive high-latitude (|b| > 15deg.) HI 21cm-line absorption survey towards 102 sources using the GMRT. With a 3-sigma detection limit in optical depth of ~0.01, this is the most sensitive HI absorption survey. We…

Astrophysics · Physics 2009-11-10 Rekhesh Mohan , K. S. Dwarakanath , G. Srinivasan

A new molecular hydrogen cloud is found in the sub-damped Ly-alpha absorber [log N(HI)=19.88+/-0.05] at the redshift z=1.15 toward the bright quasar HE0515-4414 (zem = 1.71). More than 30 absorption features in the Lyman band system of H2…

Astrophysics · Physics 2009-11-10 D. Reimers , R. Baade , R. Quast , S. A. Levshakov

Using a simple model of photodissociated atomic hydrogen on a galactic scale, it is possible to derive total hydrogen volume densities. These densities, obtained through a combination of atomic hydrogen, far-ultraviolet and metallicity…

Astrophysics of Galaxies · Physics 2015-06-11 J. S. Heiner , J. R. Sánchez-Gallego , L. Rousseau-Nepton , J. H. Knapen

Cosmic voids, the under-dense regions of the cosmic web, are widely used to constrain cosmology. Voids contain few, isolated galaxies, presumably expected to be less evolved and preserving memory of the pristine Universe. We use the…

Astrophysics of Galaxies · Physics 2020-02-12 Melanie Habouzit , Alice Pisani , Andy Goulding , Yohan Dubois , Rachel S. Somerville , Jenny E. Greene

One of the most striking features in galaxy redshift surveys is the ubiquitous presence of voids. However, voids have not been extensively studied due to observational limitations. Until recently, galaxy redshift surveys included only a few…

Astrophysics · Physics 2007-05-23 Fiona Hoyle , Michael S Vogeley

We investigate the environmental dependence of galaxy population properties in a complete volume-limited sample of 91566 galaxies in the redshift range 0.05 <= z <= 0.095 and with M_r <= -20.0, selected from the Sloan Digital Sky Survey…

Astrophysics · Physics 2009-11-11 G. Sorrentino , V. Antonuccio-Delogu , A. Rifatto

We have recently identified several high velocity (V < -100 km/s) clouds in the directions of Mrk 509 and PKS 2155-304 that have unusual ionization properties. The clouds exhibit strong C IV absorption with little or no detectable low ion…

Astrophysics · Physics 2009-10-30 Kenneth R. Sembach , Blair D. Savage , Limin Lu , Edward M. Murphy

Cold gas streaming along the dark-matter filaments of the cosmic web is predicted to be the major provider of resources for disc buildup, violent disk instability and star formation in massive galaxies in the early universe. We study to…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Tobias Goerdt , Avishai Dekel , Amiel Sternberg , Orly Gnat , Daniel Ceverino

We model the kinematics of the high- and intermediate- velocity clouds (HVCs and IVCs) observed in absorption towards a sample of 55 Galactic halo stars with accurate distance measurements. We employ a simple model of a thick disc whose…

Astrophysics of Galaxies · Physics 2022-05-25 A. Marasco , F. Fraternali , N. Lehner , J. C. Howk

Aims: Highly resolved maps of the local Galactic dust are an important ingredient for sky emission models. In nearly the whole electromagnetic spectrum one can see imprints of dust, many of which originate from dust clouds within 300pc.…

Astrophysics of Galaxies · Physics 2019-10-16 R. H. Leike , T. A. Enßlin

We study the physical conditions of the circum-galactic medium (CGM) around z=0.25 galaxies as traced by HI and metal line absorption, using cosmological hydrodynamic simulations that include galactic outflows. Using lines of sight targeted…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-17 Amanda Brady Ford , Benjamin D. Oppenheimer , Romeel Davé , Neal Katz , Juna A. Kollmeier , David H. Weinberg

We present ultraviolet (UV) follow-up of a sample of potential dwarf galaxy candidates selected for their neutral hydrogen (HI) properties, taking advantage of the low UV background seen by the GALEX satellite and its large and publicly…

Astrophysics of Galaxies · Physics 2015-08-06 Jennifer Donovan Meyer , J. E. G. Peek , Mary Putman , Jana Grcevich

From the $\Lambda$ cold dark matter paradigm it is expected that galaxies merge and grow in their environments. These processes form various tidal features depending on the merger mass ratio, orbital parameters, and gas richness. We…

Astrophysics of Galaxies · Physics 2025-02-21 Jan-Niklas Pippert , Matthias Kluge , Ralf Bender

CONTEXT. Hydrodynamical cosmological simulations predict flows of the intergalactic medium along the radial vector of the voids, approximately in the direction of the infall of matter at the early stages of the galaxy formation. AIMS. These…

The [CII] fine--structure line at 158um is an excellent tracer of the warm diffuse gas in the ISM and the interfaces between molecular clouds and their surrounding atomic and ionized envelopes. Here we present the initial results from…

Analysis of interstellar absorption lines observed in high-resolution {\em HST} spectra of nearby stars provides temperatures, turbulent velocities, and kinetic properties of warm interstellar clouds. Previous studies identified 15 warm…

Astrophysics of Galaxies · Physics 2022-08-31 Jeffrey L. Linsky , Seth Redfield , Diana Ryder , Adina Chasan-Taber

As a complement to the HyGAL Stratospheric Observatory for Infrared Astronomy Legacy Program, we report the results of a ground-based absorption line survey of simple molecules in diffuse and translucent Galactic clouds. Using the Institut…

We derived the dust-to-HI ratio of the intermediate-velocity clouds (IVCs), the high-velocity clouds (HVCs), and the local HI gas, by carrying out a multiple-regression analysis of the 21cm HI emission combined with the sub-mm dust optical…

Astrophysics of Galaxies · Physics 2024-01-24 Takahiro Hayakawa , Yasuo Fukui

Recent submillimeter and far-infrared wavelength observations of absorption in the rotational ground-state lines of various simple molecules against distant Galactic continuum sources have opened the possibility of studying the chemistry of…

Astrophysics of Galaxies · Physics 2017-02-21 B. Winkel , H. Wiesemeyer , K. M. Menten , M. Sato , A. Brunthaler , F. Wyrowski , D. Neufeld , M. Gerin , N. Indriolo