Related papers: Galactic Abundance Patterns via Peimbert Types I &…
Planetary nebulae (PNe) can be used to trace intermediate and old stellar populations in galaxies and the intracluster medium out to approximately 20 Mpc. PNe can be easily identified with narrow-band surveys, and their chemical abundances…
In the last decade, ground-based Imaging Atmospheric Cherenkov Telescopes have discovered about 175 very-high-energy (VHE; $E >$ 100 GeV) gamma-ray sources, with more to follow with the development of H.E.S.S. II and CTA. Nearly 40 of these…
Iron suffers from high levels of depletion in the highly ionized environments of planetary nebulae, making the direct determination of undepleted elemental iron abundances difficult. Zinc, which does not suffer from the same depletion…
Understanding which stars explode as which type of supernovae (SNe) is crucial to measure their contribution to the metal production and feedback halting star formation. Most of the studies of the gas in the environment of SNe are limited…
This paper examines, compares and plots optical, near- and mid-infrared (MIR) photometric data for 605 planetary nebulae (PNe) in the Large Magellanic Cloud (LMC). With the aid of multi-wavelength surveys such as the Spitzer legacy…
Planetary nebulae (PN) are an essential tool in the study of the chemical evolution of the Milky Way and galaxies of the Local Group, particularly the Magellanic Clouds. In this work, we present some recent results on the determination of…
The detailed study of supernovae (SNe) and their progenitors allows to better understand the evolution of massive stars and how these end their lives. Despite its importance, the range of physical parameters for the most common type of…
The majority of planetary nebulae (PNe) are not spherical, and current single-star models cannot adequately explain all the morphologies we observe. This has led to the Binary Hypothesis, which states that PNe are preferentially formed by…
This paper represents the conclusion of a project that had two main goals: (1) to investigate to what extent planetary nebulae (PNe) are chemically homogeneous; and (2) to provide physical constraints on the central star properties of each…
We present spectroscopy of three planetary nebulae (PNe) in the Northern Spur of the Andromeda Galaxy (M31) obtained with the Double Spectrograph on the 5.1 m Hale Telescope at the Palomar Observatory. The samples are selected from the…
Emission-line abundances have been uncertain for more than a decade due to unexplained discrepancies in the relative intensities of the forbidden lines and weak permitted recombination lines in planetary nebulae (PNe) and H II regions. The…
We present the first results of our search for new, extended Planetary Nebulae (PNe) based on careful, systematic, visual scrutiny of the imaging data from the INT Photometric H-alpha Survey of the Northern Galactic Plane (IPHAS). The newly…
We investigate the oxygen and nitrogen abundance distributions across the optical disks of 130 nearby late-type galaxies using around 3740 published spectra of HII regions. We use these data in order to provide homogeneous abundance…
Elemental abundance ratios as tracers of stellar populations are discussed with emphasis on F, G, and K stars providing a `fossil' record of the chemical evolution of the Galaxy. Most abundance studies have been based on homogeneous 1D…
We explore a method for metallicity determinations based on quantitative spectroscopy of type II-Plateau (II-P) supernovae (SNe). For consistency, we first evolve a set of 15Msun main sequence stars at 0.1, 0.4, 1, and 2 x the solar…
Utilising the optical imaging Fourier transform spectrograph SITELLE, the Star-formation, Ionized Gas and Nebular Abundances Legacy Survey (SIGNALS) is designed to study the connection between star-forming regions and their environments.…
We present results of our study of two planetary nebulae (PNe), PB1 and PC 19. We use the optical spectra of these two PNe observed at 2 m Himalayan Chandra Telescope and also archival and literature data for the study. We use the…
Recent analyses of nebular spectra have resulted in discrepant abundances from CNO forbidden and recombination lines. We consider independent methods of determining ion abundances for emission nebulae, comparing ion emission measures with…
Chemical evolution models are useful for understanding the formation and evolution of stars and galaxies. Model predictions will be more robust as more observational constraints are used. We present chemical evolution models for the dwarf…
Our unified chemical and spectrophotometric evolution code allows to simultaneously study the ISM abundances of a series of elements and the spectral properties of the stellar population in our model galaxies. We use stellar evolutionary…