Related papers: Galaxy emission line classification using 3D line …
We propose a new diagram, the Kinematic-Excitation diagram (KEx diagram), which uses the [OIII]/H\beta\ line ratio and the [OIII]5007 emission line width (\sigma_{[OIII]}) to diagnose the ionization source and physical properties of the…
Optical diagnostic diagrams are frequently ambiguous as a test of the photoionization or fast shock models of the narrow line regions of active galaxies. Here, we present a set of UV line ratio diagrams which can discriminate between pure…
We review the use of emission-lines for understanding galaxy evolution, focusing on excitation source, metallicity, ionization parameter, ISM pressure and electron density. We show that the UV, optical and infrared contain complementary…
Optical emission lines are used to categorize galaxies into three groups according to their dominant central radiation source: active galactic nuclei, star formation, or low-ionization (nuclear) emission regions [LI(N)ERs] that may trace…
In the optical spectra of galaxies, methods for the separation of line emission arising from star formation and an additional hard component, such as shocks or AGN, is well-understood and possible with current diagnostics. However, such…
We present new quantitative classification methods for emission-line galaxies, which are specially designed to be used in deep galaxy redshift surveys. A good segregation between starbursts and active galactic nuclei, i.e. Seyferts 2s and…
The excitation sources in galaxies are frequently mixed due to AGN and stellar feedback, including star formation, active galactic nuclei (AGNs), and shock excitation. Disentangling the star formation, AGN, and shocks in galaxy…
The usual approach to classify the ionizing source using optical spectroscopy is based on the use of diagnostic diagrams that compares the relative strength of pairs of collisitional metallic lines (e.g., [O iii] and [N ii]) with respect to…
Studies of the Diffuse Ionized Gas (DIG) have progressed without providing so far any strict criterion to distinguish DIGs from HII regions. In this work, we compile the emission line measurements of 29 galaxies that are available in the…
We have carried out extensive and detailed photoionization modeling to successfully constrain the locations of different emission-line galaxies in optical and mid-infrared diagnostic diagrams. Our model grids cover a wide range in parameter…
We analyze the validity of optical diagnostic diagrams relying on emission-lines ratios and in the context of classifying Active Galactic Nuclei (AGNs) according to the cosmic metallicity evolution in the redshift range 0 < z < 11.2. In…
In this paper we present a classification of emission-line galaxies at intermediate and high redshifts (0.52.5 for near-infrared spectra), using the Dn(4000) index as a supplementary diagnostic. Our goal is to complement the diagnostic…
(abridged) The overwhelming majority of diagnostic tools for galactic activity are focused on active galaxies. Passive or dormant galaxies are often excluded from these diagnostics which usually employ emission line features. In this work,…
Buried active galactic nuclei and obscured young stellar clusters pose significant challenges to traditional optical diagnostic diagrams. Therefore, developing new tools to trace the excitation sources across the spectrum is a necessary…
Narrow emission-line galaxies can be distinguished in the well-known BPT diagrams through narrow emission line properties. However, there are no boundaries visible to the naked eye between type-2 AGN and HII galaxies in BPT diagrams,…
Optical emission-line diagnostic diagrams, such as the classical BPT, are widely used to identify ionisation mechanisms in galaxies but often suffer from degeneracies, especially when multiple sources coexist. We critically evaluate the…
Optical diagnostic diagrams are powerful tools to separate different ionizing sources in galaxies. However, the model-constraining power of the most widely-used diagrams is very limited and challenging to visualize. In addition, there have…
Gas metallicity, ionization parameter, and gas pressure can affect the observed ratios of specific strong emission lines within galaxies. While the theoretical strong lines diagnostics for gas metallicity, ionization parameters, and gas…
Line intensity mapping is emerging as a novel method that can measure the collective intensity fluctuations of atomic/molecular line emission from distant galaxies. Several observational programs with various wavelengths are ongoing and…
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…