Understanding Galaxy Evolution Through Emission Lines

Kewley, Lisa J.; Nicholls, David C.; Sutherland, Ralph S.

doi:10.1146/annurev-astro-081817-051832

Cited by 436 publications

(512 citation statements)

References 432 publications

(469 reference statements)

Supporting

Mentioning

480

Contrasting

Order By: Relevance

“…Our ξ ion measurements are lower compared to model predictions and such differences could be driven by differences in the stellar population/ISM properties (e.g., Kewley et al 2019), calibration uncertainties, and/or the choice of the dust attenuation curve. In Nanayakkara et al (2016) we showed that the relative calibration between ZFIRE spectra and ZFOURGE photometry agrees within 10%.…”

Section: The Observed Distribution Of ξ Ionmentioning

confidence: 55%

Reconstructing the Observed Ionizing Photon Production Efficiency at z ∼ 2 Using Stellar Population Models

Nanayakkara

Brinchmann

Glazebrook

et al. 2020

ApJ

View full text Add to dashboard Cite

The ionizing photon production efficiency, ξ ion , is a critical parameter that provides a number of physical constraints to the nature of the early Universe, including the contribution of galaxies to the timely completion of the reionization of the Universe. Here we use KECK/MOSFIRE and ZFOURGE multi-band photometric data to explore the ξ ion of a population of galaxies at z ∼ 2 with log 10 (M * /M ) ∼ 9.0 − 11.5. Our 130 Hα detections show a median log 10 (ξ ion [Hz/erg]) of 24.8 ± 0.5 when dust corrected using a Calzetti et al. (2000) dust prescription. Our values are typical of mass/magnitude selected ξ ion values observed in the z ∼ 2 Universe. Using BPASSv2.2.1 and Starburst99 stellar population models with simple parametric star-formation-histories (SFH), we find that even with models that account for effects of stellar evolution with binaries/stellar rotation, model galaxies at log 10 (ξ ion [Hz/erg]) 25.0 have low Hα equivalent widths (EW) and redder colors compared to our z ∼ 2 observed sample. We find that introducing star-bursts to the SFHs resolve the tension with the models, however, due to the rapid time evolution of ξ ion , Hα EWs, and rest-frame optical colors, our Monte Carlo simulations of star-bursts show that random distribution of star-bursts in evolutionary time of galaxies are unlikely to explain the observed distribution. Thus, either our observed sample is specially selected based on their past SFH or stellar models require additional mechanisms to reproduce the observed high UV luminosity of galaxies for a given production rate of hydrogen ionizing photons.

show abstract

Section: The Observed Distribution Of ξ Ionmentioning

confidence: 55%

Reconstructing the Observed Ionizing Photon Production Efficiency at z ∼ 2 Using Stellar Population Models

Nanayakkara

Brinchmann

Glazebrook

et al. 2020

ApJ

View full text Add to dashboard Cite

show abstract

“…As discussed in Kewley et al (2019) and in Section 4.3, small-scale (< 100 pc) observations are the missing piece to disentangle the contribution of contaminating factors to galaxy-wide quantities and relations between these. A prominent example of this is the effect of the diffuse ionized gas on measurements of e.g.…”

Section: The Diffuse Ionized Gasmentioning

confidence: 99%

Stellar Feedback and Resolved Stellar IFU Spectroscopy in the Nearby Spiral Galaxy NGC 300

McLeod

Kruijssen

Weisz

et al. 2020

ApJ

View full text Add to dashboard Cite

We present MUSE Integral Field Unit (IFU) observations of five individual HII regions in two giant (> 100 pc in radius) star-forming complexes in the low-metallicity (Z ∼ 0.33 Z ) nearby (D ∼ 2 Mpc) dwarf spiral galaxy NGC 300. We combine the IFU data with high spatial resolution Hubble Space Telescope photometry to demonstrate the extraction of stellar spectra and the classification of individual stars from ground-based data at the distance of 2 Mpc. For the two star-forming complexes, in which no O-type stars had previously been identified, we find a total of 13 newly identified O-type stars in the mass range 15−50 M , as well as 4 Wolf-Rayet stars (two already known sources and two Wolf-Rayet star candidates that are now confirmed in this work). We use the derived massive stellar content to analyze the impact of stellar feedback on the HII regions. As already found for HII regions in the Magellanic Clouds, the dynamics of the analyzed NGC 300 HII regions are dominated by a combination of the pressure of the ionized gas and stellar winds. By comparing the derived ionized gas mass loading factors to the total gas mass loading factor across the NGC 300 disk, we find that the latter is an order of magnitude higher, either indicating very early evolutionary stages for these HII regions, or being a direct result of the multi-phase nature of feedback-driven bubbles. Moreover, we analyze the relation between the star formation rate and the pressure of the ionized gas as derived from small (< 100 pc) scales, as both quantities are systematically overestimated when derived on galactic scales. With the wealth of ongoing and upcoming IFU instruments and programs, this study serves as a pathfinder for the systematic investigation of resolved stellar feedback in nearby galaxies, and it delivers the necessary analysis tools to enable massive stellar content and feedback studies sampling an unprecedented range of HII region properties across entire galaxies in the nearby Universe.

show abstract

“…The grey shaded region shows a 0.3 dex spread from the one-to-one relationship. In some cases, the optical metallicity errors may be underestimated, and ±0.3 dex represents the typical systematic errors inherent in optical strong line methods (Kewley et al 2019b).…”

Section: [Si Iii] λ18831893mentioning

confidence: 99%

A Comparison of UV and Optical Metallicities in Star-forming Galaxies

Byler

Kewley

Rigby

et al. 2020

ApJ

Self Cite

View full text Add to dashboard Cite

Our ability to study the properties of the interstellar medium (ISM) in the earliest galaxies will rely on emission line diagnostics at rest-frame ultraviolet (UV) wavelengths. In this work, we identify metallicity-sensitive diagnostics using UV emission lines. We compare UV-derived metallicities with standard, well-established optical metallicities using a sample of galaxies with rest-frame UV and optical spectroscopy. We find that the He2-O3C3 diagnostic (He II λ1640Å / C III] λ1906,1909Å vs. [O III] λ1666Å / C III] λ1906,9Å) is a reliable metallicity tracer, particularly at low metallicity (12 + log 10 (O/H) ≤ 8), where stellar contributions are minimal. We find that the Si3-O3C3 diagnostic ([Si III] λ1883Å / C III] λ1906Å vs. [O III] λ1666Å / C III] λ1906,9Å) is a reliable metallicity tracer, though with large scatter (0.2-0.3 dex), which we suggest is driven by variations in gas-phase abundances. We find that the C4-O3C3 diagnostic (C IV λ 1548,50Å / [O III] λ 1666Å vs. [O III] λ 1666Å / C III] λ 1906,9Å) correlates poorly with optically-derived metallicities. We discuss possible explanations for these discrepant metallicity determinations, including the hardness of the ionizing spectrum, contribution from stellar wind emission, and non-solar-scaled gas-phase abundances. Finally, we provide two new UV oxygen abundance diagnostics, calculated from polynomial fits to the model grid surface in the He2-O3C3 and Si3-O3C3 diagrams.

show abstract

Understanding Galaxy Evolution Through Emission Lines

Cited by 436 publications

References 432 publications

Reconstructing the Observed Ionizing Photon Production Efficiency at z ∼ 2 Using Stellar Population Models

Reconstructing the Observed Ionizing Photon Production Efficiency at z ∼ 2 Using Stellar Population Models

Stellar Feedback and Resolved Stellar IFU Spectroscopy in the Nearby Spiral Galaxy NGC 300

A Comparison of UV and Optical Metallicities in Star-forming Galaxies

Contact Info

Product

Resources

About