English
Related papers

Related papers: PyEMILI: A New Generation Computer-aided Spectral …

200 papers

We uniformly analyze 136 optically detected PNe and candidates from the GLIMPSE-I survey in order to to develop robust, multi-wavelength, classification criteria to augment existing diagnostics and provide pure PN samples. PNe represent…

Astrophysics of Galaxies · Physics 2015-05-20 Martin Cohen , Quentin A. Parker , Anne J. Green , Brent Miszalski , David J. Frew , Tara Murphy

Spectroscopy in the infrared provides a means to assess important properties of the plasma in gaseous nebulae. We present some of our own work that illustrates the need for interactions between the themes of this conference - astronomical…

We present high signal-to-noise echelle spectra of the compact high surface brightness, low ionization planetary nebula IC 418. These reveal 807 emission lines down to intensities less than 10$^{-5}$ that of H$\beta$ for which we determine…

Astrophysics · Physics 2009-11-10 Brian Sharpee , Jack A. Baldwin , Robert Williams

We present a new spectroscopic pipeline designed to analyse large numbers of hot massive stars homogeneously. The pipeline has been developed to utilise large grids of FASTWIND non-LTE, line blanketed models in which spherical geometry is…

Solar and Stellar Astrophysics · Physics 2025-10-31 PA Crowther , JM Bestenlehner

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 the results of several collisional-radiative models describing optically-thin emissivities of the main lines in neutral helium formed by recombination, for a grid of electron temperatures and densities, typical of H II regions…

Astrophysics of Galaxies · Physics 2022-04-13 G. Del Zanna , P. J. Storey

The emission lines emitted from gaseous nebulae carry valuable information about the physical conditions and chemical abundances of ionized gases in these objects, as well as the interstellar extinction. "proEQUIB" is a library containing…

Instrumentation and Methods for Astrophysics · Physics 2024-12-09 Ashkbiz Danehkar

We present a new code named pyHIIextractor, which detects and extracts the main features (positions and radii) of clumpy ionized regions, i.e. candidate HII regions, using H{\alpha} emission line images. Our code is optimized to be used on…

Accurately determining the elemental abundances of a low metallicity nebula strongly depends on measuring the density (n$_e$) and temperature (T$_e$) of the gas. Because these two parameters are inherently degenerate when derived solely…

Spectra emitted from ionized nebulae typically contain collisionally excited and recombination lines, which can be used to trace physical conditions and chemical abundances of the interstellar medium in our Galaxy and other galaxies.…

Instrumentation and Methods for Astrophysics · Physics 2024-11-26 A. Danehkar

We present a new version of the FIT3D and Pipe3D codes, two packages to derive properties of the stellar populations and the ionized emission lines from optical spectroscopy and integral field spectroscopy data respectively. The new codes…

We carry out plasma diagnostic analyses for 123 planetary nebulae (PNe) and 42 H II regions using the N II and O II optical recombination lines (ORLs). New effective recombination coefficients for the N II and O II optical recombination…

Astrophysics of Galaxies · Physics 2015-06-12 Ian A. McNabb , Xuan Fang , Xiaowei Liu , Robert J. Bastin , Peter J. Storey

Infrared and nebular lines provide some of our best probes of the physics regulating the properties of the interstellar medium (ISM) at high-redshift. However, interpreting the physical conditions of high-redshift galaxies directly from…

Diagnostic diagrams of emission-line ratios have been used extensively to categorize extragalactic emission regions; however, these diagnostics are occasionally at odds with each other due to differing definitions. In this work, we study…

Planetary nebulae (PNe) provide tests of stellar evolution, can serve as tracers of chemical evolution in the Milky Way and other galaxies, and are also used as a calibrator of the cosmological distance ladder. Current and upcoming large…

Solar and Stellar Astrophysics · Physics 2019-07-10 George Vejar , Rodolfo Montez , Margaret Morris , Keivan G. Stassun

The circumstellar environments of PNe are wonderful chemically rich astrophysical laboratories in which the ionization of atoms and the formation of simple and complex molecules can be studied. The new high-sensitivity receivers open the…

Planetary nebulae (PNe) are strong H$\alpha$ line-emitters and a lot of new PNe discoveries have been made by the SuperCOSMOS AAO/UKST H$\alpha$ Survey (SHS) and the Isaac Newton Telescope Photometric H$\alpha$ Survey (IPHAS). However, the…

Solar and Stellar Astrophysics · Physics 2019-08-20 Stavros Akras , Lizette Guzman-Ramirez , Denise R. Gonçalves

This paper continues our study of the behaviour of near infrared helium recombination lines in planetary nebula. We find that the 1.7007um 4^3D-3^3P HeI line is a good measure of the HeI recombination rate, since it varies smoothly with the…

Astrophysics · Physics 2009-11-07 S. L. Lumsden , P. J. Puxley , M. G. Hoare

We present an analysis of physical conditions in planetary nebulae (PNe) in terms of collisionally-excited line (CEL) and optical-recombination line (ORL) profiles. We aim to investigate whether line profiles could be used to study the…

Astrophysics · Physics 2009-11-13 Yong Zhang

Using the Cloudy_3D code (Morisset, this conference), we run a set of models to build a catalog of emission line profiles of PNe. The goal is to cover the main morphologies (spherical, ellipsoidal, bipolar, thin or thick shells) and to…

Astrophysics · Physics 2009-11-11 C. Morisset , G. Stasinska