相关论文: Regulated star formation in forming disk galaxies …
Regions of disc galaxies with widespread star formation tend to be both gravitationally unstable and self-shielded against ionizing radiation, whereas extended outer discs with little or no star formation tend to be stable and unshielded on…
Circumstellar disks are an essential ingredient of the formation of low-mass stars. It is unclear, however, whether the accretion-disk paradigm can also account for the formation of stars more massive than about 10 solar masses, in which…
About 20 percent of all nearby early-type galaxies ($M_{\star} \gtrsim 6 \times 10^{9}$ M$_{\odot}$) outside the Virgo cluster are surrounded by a disc or ring of low-column-density neutral hydrogen (HI) gas with typical radii of tens of…
The radial profiles of gas, stars, and far ultraviolet radiation in 20 dwarf Irregular galaxies are converted to stability parameters and scale heights for a test of the importance of two-dimensional (2D) instabilities in promoting star…
The cosmic ultraviolet background (UVB) heats the intergalactic medium (IGM), as a result the gas in dark matter halos below a certain mass is too hot to cool within a Hubble time. The UVB effectively suppresses the formation of dwarf…
There is strong evidence that the diffuse ionized gas (DIG) in disc galaxies is photoionized by radiation from UV luminous O and B stars in the galactic disc, both from observations and detailed numerical models. However, it is still not…
The pancake collapse of pregalactic clouds under UV background radiation is explored with a one-dimensional sheet model. Here, attention is concentrated on elucidating the basic physics on the thermal evolution of pregalactic clouds exposed…
We argue that star formation in the disks of low-surface-brightness (LSB) galaxies shares a similar nature with that occurring in the far outer regions of normal-brightness spiral galaxies, such as those with the extended ultraviolet (XUV)…
We explore the possibility of the formation of globular clusters under ultraviolet (UV) background radiation. One-dimensional spherical symmetric radiation hydrodynamics (RHD) simulations by Hasegawa et al. have demonstrated that the…
We investigate the evolution of star-forming gas-rich disks, using a 3D chemodynamical model including a dark halo, stars, and a two-phase interstellar medium with feedback processes from the stars. We show that galaxy evolution proceeds…
Radiation feedback is typically implemented using subgrid recipes in hydrodynamical simulations of galaxies. Very little work has so far been performed using radiation-hydrodynamics (RHD), and there is no consensus on the importance of…
Star formation depends on the available gaseous "fuel" as well as galactic environment, with higher specific star formation rates where gas is predominantly molecular and where stellar (and dark matter) densities are higher. The partition…
Star formation in galaxies is triggered by a combination of processes, including gravitational instabilities, spiral wave shocks, stellar compression, and turbulence compression. Some of these persist in the far outer regions where the…
We present ultraviolet integrated and azimuthally-averaged surface photometric properties of a sample of 44 dIm, BCD, and Sm galaxies measured from archival NUV and FUV images obtained with GALEX. We compare the UV to Halpha and V-band…
(Abridged). We model gravitational instability in a wide range of isolated disk galaxies, using GADGET, a three-dimensional, smoothed particle hydrodynamics code. The model galaxies include a dark matter halo and a disk of stars and…
The importance of radiation pressure feedback in galaxy formation has been extensively debated over the last decade. The regime of greatest uncertainty is in the most actively star-forming galaxies, where large dust columns can potentially…
We have examined star formation in two very luminous (M_V=-22 to -23) Sc-type spiral galaxies, NGC 801 and UGC 2885, using ultra-deep Halpha images. We combine these with UBV and 2MASS JHK images and HI maps to explore the star formation…
The vast majority of young stars hosting planet-forming disks exist within clustered environments, like the Orion Nebula, implying that seemingly `extreme' UV environments (10^4 G_0 and above) are not so atypical in the context of planet…
Observations indicate that some extended outer disks have a sharp cut off in the surface density of neutral hydrogen when this approaches the value of $\sim 2\times 10^{19}$ cm$^{-2}$. In this paper we model these HI edges as places where…
Disk galaxies at intermediate redshift ($z\sim0.7$) have been found in previous work to display more optically thick behaviour than their local counterparts in the rest-frame B-band surface brightness, suggesting an evolution in dust…