Photoionized Herbig–Haro objects in the Orion Nebula through deep high-spectral resolution spectroscopy – I. HH 529 II and III

Méndez-Delgado, J. E.; Esteban, C.; García‐Rojas, J.; Henney, W. J.; Mesa‐Delgado, A.; Arellano-Córdova, K. Z.

doi:10.1093/mnras/stab068

Cited by 20 publications

(17 citation statements)

References 185 publications

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“…The electron temperature can also be determined from the T e sensitive He i λ7281/λ6678 recombination line ratio, following the procedure in Zhang et al (2005). We have used the fitting coefficients computed by Méndez-Delgado et al (2021) to account for weak density dependencies and have then interpolated linearly (their table 7) the coefficients needed to solve their equation 4. For the densities considered in this work, the sensitivity of the He i λ7281/λ6678 line ratio to T e is rather low for T e lower than 2 000 K For the determination of the electron temperature from the Paschen jump (PJ), we define the jump as the difference between the continuum measured at 8100 and 8400 Å, normalized to the intensity of the H i 9-3 line.…”

Section: Electron Temperatures From He I Recombination Lines and Pasc...mentioning

confidence: 99%

MUSE spectroscopy of planetary nebulae with high abundance discrepancies

García‐Rojas

Morisset²,

Jones

et al. 2021

Monthly Notices of the Royal Astronomical Society

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We present MUSE deep integral-field unit spectroscopy of three planetary nebulae (PNe) with high abundance discrepancy factors (ADF > 20): NGC 6778, M 1–42 and Hf 2–2. We have constructed flux maps for more than 40 emission lines, and use them to build extinction, electron temperature (Te), electron density (ne), and ionic abundances maps of a number of ionic species. The effects of the contribution of recombination to the auroral [N ii] and [O ii] lines on Te and the abundance maps of low-ionization species are evaluated using recombination diagnostics. As a result, low Te values and a downward gradient of Te are found toward the inner zones of each PN. Spatially, this nearly coincides with the increase of abundances of heavy elements measured using recombination lines in the inner regions of PNe, and strongly supports the presence of two distinct gas phases: a cold and metal-rich and a warm one with “normal” metal content. We have simultaneously constructed, for the first time, the ADF maps of O+ and O2 + and found that they centrally peak for all three PNe under study. We show that the main issue when trying to compute realistic abundances from either ORLs or CELs is to estimate the relative contribution of each gas component to the H i emission, and we present a method to evaluate it. It is also found that, for the studied high-ADF PNe, the amount of oxygen in the cold and warm regions is of the same order.

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Section: Electron Temperatures From He I Recombination Lines and Pasc...mentioning

confidence: 99%

MUSE spectroscopy of planetary nebulae with high abundance discrepancies

García‐Rojas

Morisset²,

Jones

et al. 2021

Monthly Notices of the Royal Astronomical Society

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“…However, we do not exclude that stellar continuum subtraction might affect the flux measured in those lines as was suggested by Groves et al (2012). In an incoming paper, we will assess the impact of the reddening correction implied by Balmer and Paschen lines calculating E(B − V ) (Rogers et al 2021;Méndez-Delgado et al 2021;Aver et al 2021) using a different set of observations of CLASSY. In particular, the LBT observations of this paper (see Figure 2), which cover a wide range of wavelengths.…”

Section: Comparison Of the E(b − V ) Valuesmentioning

confidence: 99%

CLASSY V: The Impact of Aperture Effects on the Inferred Nebular Properties of Local Star-forming Galaxies

Arellano-Córdova

Mingozzi

Berg

et al. 2022

ApJ

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Strong nebular emission lines are an important diagnostic tool for tracing the evolution of star-forming galaxies across cosmic time. However, different observational setups can affect these lines, and the derivation of the physical nebular properties. We analyze 12 local star-forming galaxies from the COS Legacy Spectroscopy SurveY (CLASSY) to assess the impact of using different aperture combinations on the determination of the physical conditions and gas-phase metallicity. We compare optical spectra observed with the Sloan Digital Sky Survey Data Release aperture, which has a 3″ diameter similar to COS, IFU, and long-slit spectra, including new LBT/MODS observations of five CLASSY galaxies. We calculate the reddening, electron densities and temperatures, metallicities, star formation rates, and equivalent widths (EWs). We find that measurements of the electron densities and temperatures, and metallicity remained roughly constant with aperture size, indicating that the gas conditions are relatively uniform for this sample. However, using IFU observations of three galaxies, we find that the E(B − V) values derived from the Balmer ratios decrease (by up to 53%) with increasing aperture size. The values change most significantly in the center of the galaxies, and level out near the COS aperture diameter of 2.″5. We examine the relative contributions from the gas and stars using the Hα and [O iii] λ5007 EWs as a function of aperture light fraction, but find little to no variations within a given galaxy. These results imply that the optical spectra provide nebular properties appropriate for the far-UV CLASSY spectra, even when narrow 1.″0 long-slit observations are used.

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“…These spectra contain many helium lines beyond the usual strong visible transitions, some from relatively high principal quantum number. For extraction, Méndez-Delgado et al (2021) divide their slit into four "cuts", with cut 4 exclusively containing nebular material. Dereddened fluxes for some of the stronger helium lines are listed under MD09 and MD21 in Table 6, accompanied by our Case B results calculated at the temperatures and densities derived for the nebular material by the respective authors.…”

Section: The Orion Nebula Modelmentioning

confidence: 99%

Helium line emissivities for nebular astrophysics

Del Zanna,

Storey

2022

Preprint

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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 and Planetary Nebulae. Accurate emissivities are required for example to measure the helium abundance in nebulae and as a consequence its primordial value. We compare our results with those obtained by previous models, finding significant differences, well above the target accuracy of one percent. We discuss in some detail our chosen set of atomic rates and the differences with those adopted by previous models. The main differences lie in the treatment of electron and proton collision rates and we discuss which transitions are least sensitive to the choice of these rates and therefore best suited to high precision abundance determinations. We have focused our comparisons on the case B approximation where only He and He `are considered, but also present results of full models including the bare nuclei, photo-excitation and photo-ionisation and either blackbody or observed illuminating spectrum in the case of the Orion nebula, to indicate which spectral lines are affected by opacity. For those transitions, accurate radiative transfer calculations should be performed. We provide tables of emissivities for all transitions within n ď 5 and all those between the n ď 5 and n 1 ď 25 states, in the log T e [K]=10 3.0p0.1q4.6 and log N e [cm ´3]=10 2p0.5q6 ranges, and a FORTRAN code to interpolate to any T e , N e within these ranges.

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Photoionized Herbig–Haro objects in the Orion Nebula through deep high-spectral resolution spectroscopy – I. HH 529 II and III

Cited by 20 publications

References 185 publications

MUSE spectroscopy of planetary nebulae with high abundance discrepancies

MUSE spectroscopy of planetary nebulae with high abundance discrepancies

CLASSY V: The Impact of Aperture Effects on the Inferred Nebular Properties of Local Star-forming Galaxies

Helium line emissivities for nebular astrophysics

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