THEORETICAL EVOLUTION OF OPTICAL STRONG LINES ACROSS COSMIC TIME

By Lisa J. Kewley, M. Dopita, C. Leitherer, R. Dav'e, T. Yuan, M. Allen, B. Groves, R. Sutherland. 2013

267 citations recorded by the source corpus.

We use the chemical evolution predictions of cosmological hydrodynamic simulations with our latest theoretical stellar population synthesis, photoionization, and shock models to predict the strong line evolution of ensembles of galaxies from z = 3 to the present day. In this paper, we focus on the brightest optical emission-line ratios, [N ii]/Hα and [O iii]/Hβ. We use the optical diagnostic Baldwin–Phillips–Terlevich (BPT) diagram as a tool for investigating the spectral properties of ensembles of active galaxies. We use four redshift windows chosen to exploit new near-infrared multi-object spectrographs. We predict how the BPT diagram will appear in these four redshift windows given different sets of assumptions. We show that the position of star-forming galaxies on the BPT diagram traces the interstellar medium conditions and radiation field in galaxies at a given redshift. Galaxies containing active galactic nucleus (AGN) form a mixing sequence with purely star-forming galaxies. This mixing sequence may change dramatically with cosmic time, due to the metallicity sensitivity of the optical emission-lines. Furthermore, the position of the mixing sequence may probe metallicity gradients in galaxies as a function of redshift, depending on the size of the AGN narrow-line region. We apply our latest slow shock models for gas shocked by galactic-scale winds. We show that at high redshift, galactic wind shocks are clearly separated from AGN in line ratio space. Instead, shocks from galactic winds mimic high metallicity starburst galaxies. We discuss our models in the context of future large near-infrared spectroscopic surveys.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/fa17dd4662b1bfd2b80228b78d13fc8870177edb

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Citations in the corpus

Analyzing Inverse Problems with Invertible Neural Networks (2018, background): “To study this, astronomers measure emission lines from chemical elements such as hydrogen or oxygen [1, 21].”
The SINS/zC-SINF Survey of z ∼ 2 Galaxy Kinematics: SINFONI Adaptive Optics–assisted Data and Kiloparsec-scale Emission-line Properties (2018, methodology): “…ISM conditions, and possible N/O abundance variations on the [N II]/Hα ratio, as amply discussed in the literature 5 (e.g., Kewley & Dopita 2002; Kewley et al. 2013; Pérez-Montero & Contini 2009; Yuan et al. 2012; Andrews & Martini 2013; Steidel et al. 2014; Shapley et al. 2015; Sanders et…”
Using Lyman-α to detect galaxies that leak Lyman continuum (2014, background): “The observed ratio of [O iii]/[O ii] ∼ 15 of Tol 1214−277 is very high, suggesting high ionisation (and/or low metallicity) of the H ii region (Kewley & Dopita 2002; Kewley et al. 2013; Jaskot & Oey 2013; Nakajima & Ouchi 2014).”
GRB hosts through cosmic time - VLT/X-Shooter emission-line spectroscopy of 96 γ-ray-burst-selected galaxies at 0.1 (2015, methodology): “…we plot the logarithmic space density of 330000 local (z ∼ 0) SDSS (Abazajian et al. 2009) galaxies from the MPA-JHU catalogue (e.g., Kauffmann et al. 2003), as well as the redshift-dependent classification lines between AGN and star-forming galaxies as gray dashed lines (Kewley et al. 2013b).”
THE MOSDEF SURVEY: ELECTRON DENSITY AND IONIZATION PARAMETER AT z ∼ 2.3 (2015, background): “It has been proposed that the position of high-redshift galaxies in the [O iii]/Hβ vs. [N ii]/Hα diagram can be explained by a systematically harder ionizing spectrum compared to that of local galaxies with similar metallicity (Kewley et al. 2013a; Steidel et al. 2014).”
RELATIONS BETWEEN CENTRAL BLACK HOLE MASS AND TOTAL GALAXY STELLAR MASS IN THE LOCAL UNIVERSE (2015, background): “…AGN, which are likely to reside in lowmass galaxies, have line ratios significantly different from Seyferts in more metal-rich systems and overlap with low-metallicity starbursts in the [OIII]/Hβ vs. [NII]/Hα (i.e., BPT) diagram (Groves et al. 2006; Kewley et al. 2013; Reines et al. 2014).”
PHYSICAL PROPERTIES OF EMISSION-LINE GALAXIES AT z ∼ 2 FROM NEAR-INFRARED SPECTROSCOPY WITH MAGELLAN FIRE (2014, background): “The elevated [O iii]/Hβ ratios in the classical BPT diagram could be at least partially due to AGN activity in such galaxies (Trump et al. 2011, 2013; Kewley et al. 2013a).”
THE MOSDEF SURVEY: EXCITATION PROPERTIES OF z ∼ 2.3 STAR-FORMING GALAXIES (2014, methodology): “…inspired many different explanations, including evolution with redshift in the typical interstellar pressure, and typical H II-region ionization parameters, electron densities, density structure, and ionizing spectra (Liu et al. 2008; Brinchmann et al. 2008; Kewley et al. 2013; Yeh et al. 2013).”
Physical Models of Galaxy Formation in a Cosmological Framework (2014, background): “However, calibration uncertainties in metallicity measures owing to evolving ISM conditions (Kewley et al. 2013) make the redshift independence difficult to robustly confirm, and even the existence of this second-parameter trend with SFR is not as clear at higher redshifts (Sanders et al. 2014,…”
EVIDENCE FOR WIDE-SPREAD ACTIVE GALACTIC NUCLEUS-DRIVEN OUTFLOWS IN THE MOST MASSIVE z ∼ 1–2 STAR-FORMING GALAXIES (2014, background): “These ratios are at or above the highest values explainable by stellar photoionization for super-solar metallicity (Veilleux & Osterbrock 1987; Kewley et al. 2001, 2006, 2013).”
Deriving Physical Properties from Broadband Photometry with Prospector: Description of the Model and a Demonstration of its Accuracy Using 129 Galaxies in the Local Universe (2016, background): “This is due to their sensitivity to the ionization parameter (Kewley et al. 2013).”
ALMA SPECTROSCOPIC SURVEY IN THE HUBBLE ULTRA DEEP FIELD: THE INFRARED EXCESS OF UV-SELECTED z = 2–10 GALAXIES AS A FUNCTION OF UV-CONTINUUM SLOPE AND STELLAR MASS (2016, background): “…to output large amounts of ionizing radiation tens of million of years after an initial burst of star formation (e.g., Yoon et al. 2006; Eldridge & Stanway 2009, 2012; Levesque et al. 2012; de Mink et al. 2013; Kewley et al. 2013; Leitherer et al. 2014; Szécsi et al. 2015; Gräfener et al. 2015).”
FORMING COMPACT MASSIVE GALAXIES (2015, background): “Such winds can be driven by star formation (e.g., Heckman, Armus, & Miley 1987) and/or AGNs (e.g., Proga, Stone, & Kallman 2000) and are ubiquitous in star forming galaxies at high redshifts (Franx et al. 1997; Pettini et al. 1998; Förster Schreiber et al. 2014; Genzel et al. 2014a).”
Metallicity evolution, metallicity gradients, and gas fractions at z ~ 3.4 (2013, background): “It has been recently argued that the excitation conditions in high-z galaxies are different from the local ones and that, therefore, the local calibrations may not apply to high redshift (Kewley et al. 2013).”
Chemical abundances in high-redshift galaxies: a powerful new emission line diagnostic (2016, background): “It is likely that a change in both ionization parameter and in the ISM pressure is responsible for this difference (Brinchmann et al. 2008; Liu et al. 2008; Hainline et al. 2009; Bian et al. 2010; Nakajima et al. 2012; Kewley et al. 2013a).”
SDSS-IV MaNGA : the impact of diffuse ionized gas on emission-line ratios, interpretation of diagnostic diagrams and gas metallicity measurements (2016, background): “When metallicity, ionization parameter, density, or ionizing spectrum change, the location of ionized gas on the BPT diagram changes (e.g., Dopita et al. 2000, 2013; Kewley et al. 2002, 2013a,b).”
STRONG NEBULAR LINE RATIOS IN THE SPECTRA of z ∼ 2–3 STAR FORMING GALAXIES: FIRST RESULTS FROM KBSS-MOSFIRE (2014, methodology): “Expectations for the behavior of high-redshift AGN in the BPT plane have been explored in some detail by Kewley et al. (2013a), who pointed out that AGN in low metallicity hosts (which appear to be extremely rare at z ' 0) could conceivably be found with high [OIII]/Hβ but low [NII]/Hα.”
Spectroscopy of superluminous supernova host galaxies. A preference of hydrogen-poor events for extreme emission line galaxies (2014, methodology): “In the region of interest for H-poor SLSN hosts, an increase in q leads to an increase in the [O III]/Hβ ratio and we have marked this on our graph with a qualitative arrow similar to Kewley et al. (2013b).”