Chemical Composition and Mixing in Giant H<scp>ii</scp>Regions: NGC 3603, 30 Doradus, and N66

Lebouteiller, V.; Bernard─Salas, J.; Brandl, Bernhard R.; Whelan, David G.; Wu, Yanling; Charmandaris, V.; Devost, D.; Houck, J. R.

doi:10.1086/587503

Cited by 69 publications

(101 citation statements)

References 75 publications

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“…The heliocentric radial velocity of DdDm-1 is À310:3 AE 1:4 km s À1 . 8 See also the discussion of Ne and S abundances in H ii regions in Lebouteiller et al (2008).…”

Section: Discussionmentioning

confidence: 99%

A Multiwavelength Analysis of the Halo Planetary Nebula DdDm‐1

Henry

Kwitter

Dufour

et al. 2008

ApJ

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We present new HST optical imagery as well as new UVand IR spectroscopic data obtained with the Hubble Space Telescope and Spitzer Space Telescope, respectively, of the halo planetary nebula DdDm-1. For the first time we present a resolved image of this object, which indicates that the morphology of DdDm-1 can be described as two orthogonal elliptical components in the central part surrounded by an extended halo. The extent of the emission is somewhat larger than was previously reported in the literature. We combine the spectral data with our own previously published optical measurements to derive nebular abundances of He, C, N, O, Ne, Si, S, Cl, Ar, and Fe. The metallicity, as gauged by oxygen, is found to be 0.60 dex below the solar value, confirming DdDm-1's status as a halo PN. In addition, we find that Si and Fe are markedly underabundant, suggesting their depletion onto dust. The very low C/O ratio suggests that the chemistry of the nebula should be consistent with an oxygen-rich environment. With regard to the unexpectedly low S abundance relative to O often seen in PNe, we find that the sulfur abundance of DdDm-1 is only slightly below the value expected based on the normal lockstep behavior between S and O observed in H ii regions and blue compact galaxies. We performed a photoionization model analysis from which we inferred a central star effective temperature and luminosity of 55,000 K and 1000 L , respectively, implying an initial progenitor mass of <1 M . Finally, we report on a new radial velocity determination from echelle observations.

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“…The heliocentric radial velocity of DdDm-1 is À310:3 AE 1:4 km s À1 . 8 See also the discussion of Ne and S abundances in H ii regions in Lebouteiller et al (2008).…”

Section: Discussionmentioning

confidence: 99%

A Multiwavelength Analysis of the Halo Planetary Nebula DdDm‐1

Henry

Kwitter

Dufour

et al. 2008

ApJ

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“…by Indebetouw et al (2009) using the package PAHFIT (Smith et al 2007b). Finally, we also use the Spitzer/IRS highresolution spectra presented by Lebouteiller et al (2008) to measure the H 2 lines.…”

Section: Spitzer/irs Spectroscopymentioning

confidence: 99%

A milestone toward understanding PDR properties in the extreme environment of LMC-30 Doradus

Chevance

Madden

Lebouteiller

et al. 2016

A&A

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103

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Context. More complete knowledge of galaxy evolution requires understanding the process of star formation and the interaction between the interstellar radiation field and interstellar medium (ISM) in galactic environments traversing a wide range of physical parameter space. We focus on the impact of massive star formation on the surrounding low metallicity ISM in 30 Doradus in the Large Magellanic Cloud (LMC). A low metal abundance, which can characterizes some galaxies of the early Universe, results in less ultraviolet (UV) shielding for the formation of the molecular gas necessary for star formation to proceed. The half-solar metallicity gas in this region is strongly irradiated by the super star cluster R136, making it an ideal laboratory to study the structure of the ISM in an extreme environment. Aims. Our goal is to construct a comprehensive, self-consistent picture of the density, radiation field, and ISM structure in the most active star-forming region in the LMC, 30 Doradus. Our spatially resolved study investigates the gas heating and cooling mechanisms, particularly in the photodissociation regions (PDR) where the chemistry and thermal balance are regulated by far-UV photons (6 eV < hν < 13.6 eV). Methods. We present Herschel observations of far-infrared (FIR) fine-structure lines obtained with PACS and SPIRE/FTS. We combined atomic fine-structure lines from Herschel and Spitzer observations with ground-based CO data to provide diagnostics on the properties and structure of the gas by modeling it with the Meudon PDR code. For each tracer we estimate the possible contamination from the ionized gas to isolate the PDR component. We derive the spatial distribution of the radiation field, the pressure, the size, and the filling factor of the photodissociated gas and molecular clouds. Results. We find a range of pressure of ∼10 5 −1.7×10 6 cm −3 K and a range of incident radiation field G UV ∼ 10 2 −2.5×10 4 through PDR modeling. Assuming a plane-parallel geometry and a uniform medium, we find a total extinction A max V of 1-3 mag, which corresponds to a PDR cloud size of 0.2 to 3pc with small CO depth scale of 0.06 to 0.5 pc. At least 90% of the [C ii] originates in PDRs in this region, while a significant fraction of the L FIR (up to 70% in some places) can be associated with an ionized gas component. Theratio (2 to 60) throughout the observed map, correlated with the filling factor, reveals the porosity of the ISM in this region, which is traversed by hard UV photons surrounding small PDR clumps. We also determine the three-dimensional structure of the gas, showing that the clouds are distributed 20 to 80 pc away from the main ionizing cluster, R136.

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“…The structure of the ISM and infrared sources were examined with MIR observations (Nürnberger 2003;Nürnberger & Stanke 2003). MIR spectroscopic observations were performed using the Spitzer/IRS and spatial variations in both polycyclic aromatic hydrocarbons (PAHs) and elemental abundances were examined (Lebouteiller et al 2007(Lebouteiller et al , 2008.…”

Section: Targetsmentioning

confidence: 99%

Properties of active galactic star-forming regions probed by imaging spectroscopy with the Fourier transform spectrometer (FTS) onboard AKARI

Okada

Kawada

Murakami

et al. 2010

A&A

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Aims. We investigate the structure of the interstellar medium (ISM) and identify the location of possible embedded excitation sources from far-infrared (FIR) line and mid-infrared continuum emission maps. Methods. We carried out imaging spectroscopic observations of four giant Galactic star-forming regions with the Fourier transform spectrometer (FTS) onboard AKARI. We obtained [O III] 88 μm and [C II] 158 μm line intensity maps of all the regions: G3.270-0.101, G333.6-0.2, NGC 3603, and M 17. Results. For G3.270-0.101, we obtained high-spatial-resolution [O III] 88 μm line-emission maps and a FIR continuum map for the first time, which imply that [O III] 88 μm emission identifies the excitation sources more clearly than the radio continuum emission. In G333.6-0.2, we found a local [O III] 88 μm emission peak, which is indicative of an excitation source. This is supported by the 18 μm continuum emission, which is considered to trace the hot dust distribution. For all regions, the [C II] 158 μm emission is distributed widely as suggested by previous observations of star-forming regions. Conclusions. We conclude that [O III] 88 μm emission traces the excitation sources more accurately than the radio continuum emission, especially where there is a high density and/or column density gradient. The FIR spectroscopy provides a promising means of understanding the nature of star-forming regions.

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Chemical Composition and Mixing in Giant HiiRegions: NGC 3603, 30 Doradus, and N66

Cited by 69 publications

References 75 publications

A Multiwavelength Analysis of the Halo Planetary Nebula DdDm‐1

A Multiwavelength Analysis of the Halo Planetary Nebula DdDm‐1

A milestone toward understanding PDR properties in the extreme environment of LMC-30 Doradus

Properties of active galactic star-forming regions probed by imaging spectroscopy with the Fourier transform spectrometer (FTS) onboard AKARI

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