Related papers: Hydrodynamical models of cometary HII regions
We present an evolutionary sequence of models of the photoionized disk-wind outflow around forming massive stars based on the Core Accretion model. The outflow is expected to be the first structure to be ionized by the protostar and can…
The properties of molecular clouds associated with 10 HII regions were studied using CO observations. We identified 142 dense clumps within our sample and found that our sources are divided into two categories: those with clumps that show a…
Fragmentation and evolution for the molecular shells of the compact HII regions are less explored compared to their evolved counterparts. We map nine compact HII regions with a typical diameter of 0.4 pc that are surrounded by molecular…
We analyze the distribution of the interstellar matter in the environs of the HII region Gum31, excited by the open cluster NGC3324, located in the complex Carina region, with the aim of investigating the action of the massive stars on the…
(Abridged) We present the results of three-dimensional radiation-hydrodynamics simulations of the formation and evolution of early HII/HeIII regions around the first stars. Cooling (by H2 and HD) and recollapse of the gas in the relic HII…
We simulate the ionization environment of z ~ 20 luminous objects formed within the framework of the current CDM cosmology and compute their UV escape fraction. These objects are likely single very massive stars that are copious UV…
We analyze the dynamical expansion of the HII region, photodissociation region, and the swept-up shell, solving the UV- and FUV-radiative transfer, the thermal and chemical processes in the time-dependent hydrodynamics code. Following our…
We study the presence of low intensity high velocity components, which we have termed wing features in the integrated Halpha emission line profiles of the HII region populations of the spiral barred galaxies NGC 1530, NGC 3359 and NGC 6951.…
Our goal is to identify bipolar HII regions and to understand their morphology, their evolution, and the role they play in the formation of new generations of stars. We use the Spitzer and Herschel Hi-GAL surveys to identify bipolar HII…
We present multiwavelength investigation of morphology, physical-environment, stellar contents and star formation activity in the vicinity of star-forming region Sh 2-100. It is found that the Sh 2-100 region contains seven HII regions of…
We build, as far as theory will permit, self consistent model HII regions around central clusters of aging stars. These produce strong emission line diagnostics applicable to either individual HII regions in galaxies, or to the integrated…
We develop a simple analytic model for what happens when an O star (or compact cluster of OB stars) forms in a shock compressed layer and carves out an approximately circular hole in the layer, at the waist of a bipolar HII Region (HIIR).…
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…
We present observations of the H91$\alpha$ recombination line emission towards a sample of nine HII regions associated with 6.7-GHz methanol masers, and report arcsecond-scale emission around compact cores. We derive physical parameters for…
The S254-258 star-forming complex is a place of massive star formation where five OB-stars have created HII regions, visible as optical nebulae, and disrupted the parental molecular gas. In this work, we study the 3D structure of these \HII…
We analyze the expansion signatures of 35 HII regions mapped in [CII] 158 micron emission by the Stratospheric Observatory for Infrared Astronomy (SOFIA). The [CII] emission primarily traces photodissociation regions (PDRs) at the…
We present deep Very Large Array H66$\alpha$ radio recombination line (RRL) observations of the two cometary HII regions in DR 21. With these sensitive data, we test the "hybrid" bow shock/champagne flow model previously proposed for the DR…
The nebular properties (electronic density, extinction, age, O/H abundances) of HII regions found along the bars of the sample of barred spiral galaxies studied by Martin & Friedli (1997) are examined. From line ratio diagnostic diagrams,…
We present near-IR SINFONI observations of three Galactic HII regions: RVW79, RCW82 and RCW120. We identify the ionizing stars of each region: they are early to late O stars, close to the main sequence. We derive their stellar and wind…
Data from the Canadian Galactic Plane Survey reveal an abundance of HI shells and arcs in the disk of our galaxy. While their shape is suggestive of stellar winds or supernovae influence, very few of these structures have been examined in…