English
Related papers

Related papers: Topology and Sizes of HII Regions during Cosmic Re…

200 papers

We explore to what extent simple algebraic models can be used to describe H II regions when winds, radiation pressure, gravity and photon breakout are included. We a) develop algebraic models to describe the expansion of photoionised H II…

Astrophysics of Galaxies · Physics 2020-01-08 Sam Geen , Eric Pellegrini , Rebekka Bieri , Ralf Klessen

Ultracompact and hypercompact HII regions appear when a star with a mass larger than about 15 solar masses starts to ionize its own environment. Recent observations of time variability in these objects are one of the pieces of evidence that…

Astrophysics of Galaxies · Physics 2015-05-28 Roberto Galván-Madrid , Thomas Peters , Eric Keto , Mordecai-Mark Mac Low , Robi Banerjee , Ralf S. Klessen

We present MUSE integral field data of two HII region complexes in the Large Magellanic Cloud (LMC), N44 and N180. Both regions consist of a main superbubble and a number of smaller, more compact HII regions that formed on the edge of the…

Astrophysics of Galaxies · Physics 2018-10-17 A. F. McLeod , J. E. Dale , C. J. Evans , A. Ginsburg , J. M. D. Kruijssen , E. W. Pellegrini , S. K. Ramsay , L. Testi

The emission line ratios [OIII]5007/H-beta and [NII]6584/H-alpha have been adopted as an empirical way to distinguish between the fundamentally different mechanisms of ionization in emission-line galaxies. However, detailed interpretation…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Sherry C. C. Yeh , Silvia Verdolini , Mark R. Krumholz , Christopher D. Matzner , Alexander G. G. M. Tielens

Using the CoDa II simulation, we study the Ly$\alpha$ transmissivity of the intergalactic medium (IGM) during reionization. At $z>6$, a typical galaxy without an active galactic nucleus fails to form a proximity zone around itself due to…

We present in here the exploration of the physical properties of the sample of HII regions and aggregations of the last HII regions catalog of the CALIFA survey. This sample comprises the optical spectroscopic properties of more than…

The concordance model of cosmology and structure formation predicts the formation of isolated very massive stars at high redshifts in dark matter dominated halos of 10^5 to 10^6 Msun. These stars photo-ionize their host primordial molecular…

Astrophysics · Physics 2008-11-26 Tom Abel , John H. Wise , Greg L. Bryan

Medium-resolution spectra from 3650 angstroms to 10,000 angstroms are presented for 96 giant H II regions distributed in 20 spiral galaxies. We have calculated two separate grids of photoionization models, adopting single-star atmospheres…

Astrophysics · Physics 2009-10-30 F. Bresolin , R. C. Kennicutt , D. R. Garnett

We provide new ionization correction factors (ICFs) for carbon, nitrogen, neon, sulfur, chlorine, and argon in giant H II regions. The ICFs were computed using the most representative photoionization models from a large initial grid. The…

Astrophysics of Galaxies · Physics 2021-06-09 A. Amayo , G. Delgado-Inglada , G. Stasinska

We analyze the statistical properties of the circumnuclear HII regions of a sample of 52 nearby galaxies ($v < 1000km/s) from archival HST/NICMOS H-band and Pa alpha (1.87micron) observations at unprecedented spatial resolutions of between…

Astrophysics · Physics 2009-11-06 Almudena Alonso-Herrero , Johan H. Knapen

We present cosmological, radiation-hydrodynamics simulations of galaxy formation during the epoch of reionization in an effort towards modelling the interstellar medium (ISM) and interpreting ALMA observations. Simulations with and without…

Astrophysics of Galaxies · Physics 2018-05-02 Harley Katz , Taysun Kimm , Debora Sijacki , Martin Haehnelt

During the EoR, the first stars and galaxies appear while creating ionized bubbles that will eventually percolate near z=6. These ionized bubbles and percolation process are nowadays under a lot of scrutiny since observations of the HI gas…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-14 Emilie Thélie , Dominique Aubert , Nicolas Gillet , Pierre Ocvirk

We use radiative transfer to study the growth of ionized regions around the brightest, z=8 quasars in a large cosmological hydrodynamic simulation that includes black hole growth and feedback (the MassiveBlack simulation). We find that in…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Yu Feng , Rupert A. C. Croft , Tiziana Di Matteo , Nishikanta Khandai

One of the fundamental factors regulating the evolution of galaxies is stellar feedback. However, we still do not have strong observational constraints on the relative importance of the different feedback mechanisms (e.g. radiation, ionised…

The TYPHOON program is producing an atlas of spectroscopic data cubes of 44 large-angular-sized galaxies with complete spatial coverage from 3650-9000 A. This survey provides an unparalleled opportunity to study variations in the…

Astrophysics of Galaxies · Physics 2022-11-14 Kathryn Grasha

The spatial inhomogeneity is one of the important features for understanding the reionization process; however, it has not yet been fully quantified. To map this inhomogeneous distribution, we simultaneously detect Ly$\alpha$ emitters…

In this work we present a new hybrid method to simulate the thermal effects of the reionization in cosmological hydrodynamical simulations. The method improves upon the standard approach used in simulations of the intergalactic medium (IGM)…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-11 Jose Oñorbe , F. B. Davies , Z. Lukić , J. F. Hennawi , D. Sorini

We conduct Smoothed Particle Hydrodynamics simulations of the `collect and collapse' scenario (Elmegreen and Lada, 1977) for star formation triggered by an expanding HII region. We simulate the evolution of a spherical uniform molecular…

Astrophysics · Physics 2008-11-26 J. E. Dale , I. A. Bonnell , A. P. Whitworth

Redshifted 21cm measurements of the structure of ionised regions that grow during reionization promise to provide a new probe of early galaxy and structure formation. One of the challenges of modelling reionization is to account both for…

Astrophysics of Galaxies · Physics 2015-12-16 Han-Seek Kim , J. Stuart B. Wyithe , Jaehong Park , Gregory B. Poole , C. G. Lacey , C. M. Baugh

The epoch of reionization is one of the least known chapters in the evolutionary history of the Universe. This thesis investigates two major approaches to unveil the reionization history of the Universe using HI 21-cm maps.The most…

Cosmology and Nongalactic Astrophysics · Physics 2009-06-04 Kanan K. Datta
‹ Prev 1 3 4 5 6 7 10 Next ›