SDSS IV MaNGA: Metallicity and ionisation parameter in local star-forming galaxies from Bayesian fitting to photoionisation models

Mingozzi, Matilde; Belfiore, Francesco; Cresci, G.; Bundy, Kevin; Bershady, Matthew A.; Bizyaev, Dmitry; Blanc, Guillermo A.; Boquien, M.; Drory, Niv; Fu, Hai; Maiolino, R.; Riffel, Rogemar A.; Schaefer, Adam L.; Storchi‐Bergmann, Thaisa; Telles, E.; Tremonti, Christy; Zakamska, Nadia L.; K, Zhang

doi:10.1051/0004-6361/201937203

Cited by 72 publications

(78 citation statements)

References 163 publications

(240 reference statements)

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“…The strong relation between EW(H𝛼) and position on the BPT can also be seen in the MaNGA data, as shown in Fig. 2 (Westfall et al 2019;Belfiore et al 2019;Mingozzi et al 2020): when the 4686 AGN-hosting galaxies (∼9% of the total sample) are removed using the central spectrum, the remaining spaxels with high EW(H𝛼) also have line ratios typical of star-forming galaxies, while gas ionized by shock and post-AGB stars shows low values of EW(H𝛼).…”

Section: Dig Definitionsupporting

confidence: 57%

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The diffuse ionized gas (DIG) in star-forming galaxies: the influence of aperture effects on local H ii regions

Mannucci

Belfiore

Curti

et al. 2021

Monthly Notices of the Royal Astronomical Society

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The Diffuse Ionized Gas (DIG) contributes to the nebular emission of galaxies, resulting in emission line flux ratios that can be significantly different from those produced by H ii regions. Comparing the emission of [SII]λ6717,31 between pointed observations of H ii regions in nearby galaxies and integrated spectra of more distant galaxies, it has been recently claimed that the DIG can also deeply affect the emission of bright, star-forming galaxies, and that a large correction must be applied to observed line ratios to recover the genuine contribution from H ii regions. Here we show instead that the e?ect of DIG on the integrated spectra of star-forming galaxies is lower than assumed in previous work. Indeed, aperture effects on the spectroscopy of nearby H ii regions are largely responsible for the observed difference: when spectra of local H ii regions are extracted using large enough apertures while still avoiding the DIG, the observed line ratios are the same as in more distant galaxies. This result is highly relevant for the use of strong-line methods to measure metallicity.

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Section: Dig Definitionsupporting

confidence: 57%

“…In (Luridiana et al 2015;Mingozzi et al 2020). A second spectrum is extracted at the same position with apertures up to 9 ×9 (140-420 pc), large enough to sample most of the H region emission.…”

Section: Spectra Of H Regions Of Different Aperturesmentioning

confidence: 99%

The diffuse ionized gas (DIG) in star-forming galaxies: the influence of aperture effects on local H ii regions

Mannucci

Belfiore

Curti

et al. 2021

Monthly Notices of the Royal Astronomical Society

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“…Finally, the low ionization lines are also affected by diffuse ionized gas (DIG) in galaxies, as recently discussed by Mingozzi et al (2020), Shapley et al (2019), Sanders et al (2020), and others. In the LyC emitters studied here, the contribution of the DIG would presumably be low, if we adopt the observed scaling of the DIG contribution with surface density of star-formation (e.g., Oey et al 2007;Shapley et al 2019), since the LyC emitters are compact by selection, and have a very high SFR surface density (Izotov et al 2018b).…”

Section: Low Ionization Line Diagnostics: Progress and Caveatsmentioning

confidence: 74%

“…This offset of standard photoionization models has been shown in previous work (e.g., Pérez-Montero & Vílchez 2009;Kehrig et al 2006), in which such models fail to explain the hardening in ionizing radiation shown by most lowmass, low-metallicity H ii galaxies in the O32−S23 plane. Problems with the sulfur line strengths have often been reported in the past (see, e.g., Garnett 1989;Kewley et al 2019;Mingozzi et al 2020, and references therein) ratio have for example recently been shown by Mingozzi et al (2020). Considering that this only seems to affect sulfur lines, these latter authors suggest that this is due to limitations in stellar atmosphere modeling and/or the atomic data for sulfur.…”

Section: Low Ionization Line Diagnostics: Progress and Caveatsmentioning

confidence: 97%

“…Considering that this only seems to affect sulfur lines, these latter authors suggest that this is due to limitations in stellar atmosphere modeling and/or the atomic data for sulfur. Based on the observation that the discrepancy holds for single H ii regions (from Kreckel et al 2019), Mingozzi et al (2020) exclude the role of diffuse ionized gas as a cause of this issue. However, in our study, we see in Fig.…”

Section: Low Ionization Line Diagnostics: Progress and Caveatsmentioning

confidence: 99%

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Reconciling escape fractions and observed line emission in Lyman-continuum-leaking galaxies

Ramambason

Schaerer

Stasińska

et al. 2020

A&A

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Context. Finding and elucidating the properties of Lyman-continuum(LyC)-emitting galaxies is an important step in improving our understanding of cosmic reionization. Aims. Although the z ∼ 0.3 − 0.4 LyC emitters found recently show strong optical emission lines, no consistent quantitative photoionization model taking into account the escape of ionizing photons and inhomogenous interstellar medium (ISM) geometry of these galaxies has yet been constructed. Furthermore, it is unclear to what extent these emission lines can be used to distinguish LyC emitters. Methods. To address these questions we construct one- and two-zone photoionization models accounting for the observed LyC escape, which we compare to the observed emission line measurements. The main diagnostics used include lines of [O III], [O II], and [O I] plus sulfur lines ([S II], [S III]) and a nitrogen line ([N II]), which probe regions of different ionization in the ISM. Results. We find that single (one-zone) density-bounded photoionization models cannot reproduce the emission lines of the LyC leakers, as pointed out by earlier studies, because they systematically underpredict the lines of species of low ionization potential, such as [O I] and [S II]. Introducing a two-zone model, with differing ionization parameter and a variable covering fraction and where one of the zones is density-bounded, we show that the observed emission line ratios of the LyC emitters are well reproduced. Furthermore, our model yields LyC escape fractions, which are in fair agreement with the observations and independent measurements. The [O I] λ6300 excess, which is observed in some LyC leakers, can be naturally explained in this model, for example by emission from low-ionization and low-filling-factor gas. LyC emitters with a high escape fraction (fesc ≳ 38%) are deficient both in [O I] λ6300 and in [S II] λλ6716,6731. We also confirm that a [S II] λλ6716,6731 deficiency can be used to select LyC emitter candidates, as suggested earlier. Finally, we find indications for a possible dichotomy in terms of escape mechanisms for LyC photons between galaxies with relatively low (fesc ≲ 10%) and higher escape fractions. Conclusions. We conclude that two-zone photoionization models are sufficient and required to explain the observed emission line properties of z ∼ 0.3 − 0.4 LyC emitters. This is in agreement with UV absorption line studies, which also show the co-existence of regions with high hydrogen column density (i.e., no escape of ionizing photons) and density-bounded or very low column density regions responsible for the observed escape of LyC radiation. These simple but consistent models provide a first step towards the use of optical emission lines and their ratios as quantitative diagnostics of LyC escape from galaxies.

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A fast radio burst source at a complex magnetized site in a barred galaxy

Niu

Chen

et al. 2022

Nature

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127

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Fast radio bursts (FRBs) are highly dispersed radio bursts prevailing in the universe [1][2][3] . The recent detection of FRB 200428 from a Galactic magnetar [4][5][6][7][8] suggested that at least some FRBs originate from magnetars, but it is unclear whether the majority of cosmological FRBs, especially the actively repeating ones, are produced from the magnetar channel. Here we report the detection of 1863 polarised bursts from the repeating source FRB 20201124A 9 during a dedicated radio observational campaign of Five-hundred-meter Aperture Spherical radio Telescope (FAST). The large sample of radio bursts detected in 88 hr over 54 days indicate a significant, irregular, short-time variation of the Faraday rotation measure (RM) of the source during the first 36 days, followed by a constant RM during the later 18 days. Significant circular polarisation up to 75% was observed in a good fraction of bursts. Evidence suggests that some low-level circular polarisation originates from the conversion from linear polarisation during the propagation of the radio waves, but an intrinsic radiation mechanism is required to produce the higher degree of circular polarisation. All of these features provide evidence for a more complicated, dynamically evolving, magnetised immediate environment around this FRB source. Its host galaxy was previously known 10-12 . Our optical observations reveal that it is a Milky-Way-sized, metal-rich, barred-spiral galaxy at redshift z = 0.09795 ± 0.00003, with the FRB source residing in a low stellar density, interarm region

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SDSS IV MaNGA: Metallicity and ionisation parameter in local star-forming galaxies from Bayesian fitting to photoionisation models

Cited by 72 publications

References 163 publications

The diffuse ionized gas (DIG) in star-forming galaxies: the influence of aperture effects on local H ii regions

The diffuse ionized gas (DIG) in star-forming galaxies: the influence of aperture effects on local H ii regions

Reconciling escape fractions and observed line emission in Lyman-continuum-leaking galaxies

A fast radio burst source at a complex magnetized site in a barred galaxy

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