相关论文: Diffuse Gas in Retired Galaxies: Nebular Emission …

We measure the strength of HeII$\lambda$4686 nebular emission in passively evolving ("retired") galaxies, aiming to constrain their populations of hot accreting white dwarfs (WDs) in the context of the single degenerate (SD) scenario of…

Once thought to be devoid of warm and cold interstellar matter, elliptical galaxies are now commonly observed to host extended regions of neutral and ionized gas. Outside of the innermost nuclear regions of these galaxies, the favoured…

We study the gas emission of galaxies with active star formation, consisting mostly of HII galaxies and Starbursts, as well as some Seyfert 2s, and determine chemical and physical parameters. The data consist of 19 high signal-to-noise…

To date, the question of which progenitor channel can reproduce the observed rate of Type Ia supernovae (SNe Ia) remains unresolved, with the single and double degenerate scenarios remaining the leading contenders. The former implies a…

We present a new model for computing consistently the line and continuum emission from galaxies, based on a combination of recent population synthesis and photoionization codes. We use effective parameters to describe the HII regions and…

We present the first systematic investigation of the [NeV] (14um/24um) and [SIII] (18um/33um) infrared line flux ratios, traditionally used to estimate the density of the ionized gas, in a sample of 41 Type 1 and Type 2 active galactic…

We present a new model of the nebular emission from star-forming galaxies in a wide range of chemical compositions, appropriate to interpret observations of galaxies at all cosmic epochs. The model relies on the combination of…

Using a sample of unprecedented size (about 400 objects) of H II galaxies in which the oxygen abundances have been obtained using the temperature derived from the [OIII] 4363/5007 line ratio, we confirm that the H II galaxies form a very…

In non-star-forming, passively evolving galaxies, regions with emission lines dominated by low-ionization species are classified as Low-Ionization Emission Regions (LIERs). The ionization mechanism behind such regions has long been a…

We present numerical models of the nebular emission from H II regions around young stellar populations over a range of compositions and ages. The synthetic stellar pop- ulations include both single stars and interacting binary stars. We…

Using cosmological simulations to make useful, scientifically relevant emission line predictions is a relatively new and rapidly evolving field. However, nebular emission lines have been particularly challenging to model because they are…

The classic single-degenerate model for the progenitors of Type Ia Supernova (SN Ia) predicts that the supernova ejecta should be enriched with solar-like abundance material stripped from the companion star. Spectroscopic observations of…

Galaxies occupy different regions of the [OIII]$\lambda5007$/H$\beta$-versus-[NII]$\lambda6584$/H$\alpha$ emission-line ratio diagram in the distant and local Universe. We investigate the origin of this intriguing result by modelling…

We present a new model of the optical nebular emission from HII regions by combin- ing the results of the Binary Population and Spectral Synthesis (bpass) code with the photoion- ization code cloudy (Ferland et al. 1998). We explore a…

We present a sample of 2865 emission line galaxies with strong nebular He II 4686 emissions in Sloan Digital Sky Survey Data Release 7 and use this sample to investigate the origin of this line in star-forming galaxies. We show that…

The shape of the OB-star spectral energy distribution is a critical component in many diagnostics of the ISM and galaxy properties. We use single-star HII regions from the LMC to quantitatively examine the ionizing SEDs from widely…

We place statistical constraints on Type Ia supernova (SN Ia) progenitors using 227 nebular phase spectra of 111 SNe Ia. We find no evidence of stripped companion emission in any of the nebular phase spectra. Upper limits are placed on the…

Extensive photoionization model grids for single star HII regions using a variety of recent state-of-the-art stellar atmosphere models have been computed with the main aim of constraining/testing their predicted ionizing spectra against…

We present a combined analysis of rest-frame far-UV (1000-2000 A) and rest-frame optical (3600-7000 A) composite spectra formed from very deep observations of a sample of 30 star-forming galaxies with z=2.4+/-0.1, selected to be…

We identify a sample of 22 host galaxies of Type Ia Supernovae (SNe Ia) at redshifts 0.95<z<1.8 discovered in the Hubble Space Telescope (HST) observations of the Great Observatories Origins Deep Survey (GOODS) fields. We measure the…