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I describe recent progress in terms of 3D hydrodynamical model atmospheres and 3D line formation and their applications to stellar abundance analyses of late-type stars. Such 3D studies remove the free parameters inherent in classical 1D…

天体物理学 · 物理学 2007-05-23 Martin Asplund

Uncertainties in the radial distribution of galaxies, $\boldsymbol{n}(\boldsymbol{z})$, are one of the major contributions to the error budget of early Stage-IV galaxy survey analyses of weak gravitational lensing, galaxy clustering and…

We describe the addition of Lyman-alpha resonant line transfer to our dust continuum radiation transfer code SKIRT, verifying our implementation with published results for spherical problems and using some self-designed three-dimensional…

天体物理仪器与方法 · 物理学 2021-08-04 Peter Camps , Christoph Behrens , Maarten Baes , Anand Utsav Kapoor , Robert Grand

In this paper, we provide a physical model for the origin of variations in the shapes and bump strengths of dust attenuation laws in galaxies by combining a large suite of cosmological "zoom-in" galaxy formation simulations with 3D Monte…

星系天体物理 · 物理学 2018-12-26 Desika Narayanan , Charlie Conroy , Romeel Dave , Benjamin Johnson , Gergo Popping

A numerical code for solving various Lyman alpha (Lya) radiative transfer (RT) problems is presented. The code is suitable for an arbitrary, three-dimensional distribution of Lya emissivity, gas temperature, density, and velocity field.…

天体物理学 · 物理学 2009-08-24 Peter Laursen , Alexei O. Razoumov , Jesper Sommer-Larsen , ;

Hydrogen recombination lines (HRLs) are valuable diagnostics of the physical conditions in ionized regions around high-mass stars. Understanding their broadening mechanisms and intensity trends can provide insights into the densities,…

Present grids of stellar atmosphere models are the workhorses in interpreting stellar observations, and determining their fundamental parameters. These models rely on greatly simplified models of convection, however, lending less predictive…

太阳与恒星天体物理 · 物理学 2015-06-15 Regner Trampedach , Martin Asplund , Remo Collet , Åke Nordlund , Robert F. Stein

Realistic stellar atmospheric models of two typical metal-poor giant stars in Omega Centauri that include a chromosphere influence the formation of optical lines of Oxygen I: the forbidden lines (630nm, 636nm) and the infrared triplet…

太阳与恒星天体物理 · 物理学 2016-04-20 A. K. Dupree , E. H. Avrett , R. L. Kurucz

The Lyman-alpha emission line is the strongest feature in the spectrum of most high redshift galaxies, and is typically observed as being highly asymmetric due to galactic outflows. Quantifying this asymmetry is challenging. Here, we…

星系天体物理 · 物理学 2018-08-08 Henry J. T. Childs , Elizabeth R. Stanway

In the course of our ongoing search for serendipitous high-redshift Lyman alpha (LyA) Emissionin deep archival Keck spectra, we discovered two very high equivalent width (W_{obs} ~ 450A, 2-sigma) LyA emission line candidates at z ~3 in a…

天体物理学 · 物理学 2009-10-31 Curtis Manning , Daniel Stern , Hyron Spinrad , Andrew J. Bunker

We perform non-LTE calculations of lithium in late-type stars for a wide range of stellar parameters, including quantum mechanical cross-sections for collisions with neutral hydrogen and the negative hydrogen ion. Non-LTE abundance…

太阳与恒星天体物理 · 物理学 2015-05-13 K. Lind , M. Asplund , P. S. Barklem

Stellar models with masses ranging from 0.5 to $1.3~M_\odot$ were constructed in order to compare to young cluster observations of Li and of rotation velocities. The amount of Li depletion in cool stars is sensitive to the amount of…

天体物理学 · 物理学 2009-10-22 Brian Chaboyer , P. Demarque , M. H. Pinsonneault

We calculate models of extended stellar atmospheres with a temperature in the range of 12000-40000K and a mass loss rate of $10^{-6}-10^{-4} M_{\odot}$ yr$^{-1}$. A large number of objects with emission spectra, such as luminous blue…

高能天体物理现象 · 物理学 2021-05-26 A. Kostenkov , A. Vinokurov , Y. Solovyeva , K. Atapin , S. Fabrika

We present our analysis of UV attenuation by internal dust of a large sample (N=906 galaxies) of Lyman Break Galaxies (LBGs). Using spectral energy distributions (SEDs) from the P\'EGASE galaxy spectral evolution model we apply dust…

天体物理学 · 物理学 2009-11-07 Uma P. Vijh , Adolf N. Witt , Karl D. Gordon

We highlight and discuss the importance of accounting for nebular emission in the SEDs of high redshift galaxies, as lines and continuum emission can contribute significantly or subtly to broad-band photometry. Physical parameters such as…

宇宙学与河外天体物理 · 物理学 2015-06-03 Daniel Schaerer , Stephane de Barros

With the Multi Unit Spectroscopic Explorer (MUSE), it is now possible to detect spatially extended Lyman alpha emission from individual faint (M_UV ~ -18) galaxies at redshifts, 3 < z < 6, tracing gas out to circum-galactic scales…

星系天体物理 · 物理学 2021-01-13 Peter Mitchell , Jérémy Blaizot , Corentin Cadiou , Yohan Dubois , Thibault Garel , Joakim Rosdahl

Models of radiation transport in stellar atmospheres are the hinge of modern astrophysics. Our knowledge of stars, stellar populations, and galaxies is only as good as the theoretical models, which are used for the interpretation of their…

太阳与恒星天体物理 · 物理学 2016-07-27 Maria Bergemann

We revised the treatment of interstellar dust in the KOSMA-\tau\ PDR model code to achieve a consistent description of the dust-related physics in the code. The detailed knowledge of the dust properties is then used to compute the dust…

天体物理仪器与方法 · 物理学 2012-11-16 M. Röllig , R. Szczerba , V. Ossenkopf , C. Glück

I provide an overview about star-forming galaxies at high redshift and their physical properties. Starting from the populations of Ly-$\alpha$ emitters and Lyman break galaxies, I summarize their common features and distinction. Then I…

星系天体物理 · 物理学 2018-03-14 Daniel Schaerer

We provide a brief overview of the modelling of the atmospheres of red giant stars with the 3D radiation-hydrodynamics code CO5BOLD. We emphasize aspects where 3D modelling provides additional insight beyond standard hydrostatic 1D models,…

太阳与恒星天体物理 · 物理学 2015-05-30 Hans-Gunter Ludwig , Matthias Steffen