The origin of broad emission lines in the extragalactic giant H II region NGC 2363

Roy, Jean-René; Aubé, Martin; McCall, Marshall L.; Dufour, R. J.

doi:10.1086/171035

Cited by 54 publications

(50 citation statements)

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“…In this paper, we explore the possibility that the broad emission originates from turbulent mixing at the interface between a hot cluster wind and more quiescent photoionized condensations. In our model, all gas phases are in pressure equilibrium and, because of the high temperature of the wind, the total ionized gas mass contained in the wind is much lower than postulated by Roy et al (1992), by a factor ∼T w /10 4 . Since the upper limits on T w set by the non-detection in the X-rays allows temperature values as high as 10 8 K (Sect.…”

Section: Discussionmentioning

confidence: 83%

“…Four mechanisms have been explored by Roy et al (1992) to account for the extreme gas velocities observed in NGC 2363, namely stellar winds, Thomson scattering by hot electrons, supernova remnants, and a superbubble blowout. These authors reported significant problems with each of these mechanisms and considered them to be unsatisfactory.…”

Section: Discussionmentioning

confidence: 99%

“…In NGC 2363, this broad component, first reported by Roy et al (1992), appears as a faint pedestal under the narrow Hα, Hβ and [O iii] lines of the socalled knot A (Gonzalez-Delgado et al 1994). This pedestal has an fwhm in excess of 2300 km s −1 (Drissen et al 2009, hereafter DUCBR).…”

Section: Introductionmentioning

confidence: 94%

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The broad Hα, [O III] line wings in stellar supercluster A of NGC 2363 and the turbulent mixing layer hypothesis

Binette

Drissen

Úbeda

et al. 2009

A&A

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Context. Supercluster A in the extragalactic H ii region NGC 2363 is remarkable for the hypersonic gas seen as faint extended broad emission lines with a full-width zero intensity of 7000 km s −1 . Aims. We explore the possibility that the observed broad profiles are the result of the interaction of a high-velocity cluster wind with dense photoionized clumps. Methods. The geometry considered is that of near static photoionized condensations at the surface of which turbulent mixing layers arise as a result of the interaction with the hot wind. The approximative treatment of turbulence was carried out using the mixing length approach of Cantó & Raga. The code mappings ic was used to derive the mean quantities describing the flow and to compute the line emissivities within the turbulent layers. The velocity projection in three dimensions of the line sources was carried out analytically. is uncomfortably high and alternative processes that would provide comparable constant acceleration of the emission gas up to 4000 km s −1 might have to be considered.

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Section: Discussionmentioning

confidence: 83%

Section: Discussionmentioning

confidence: 99%

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The broad Hα, [O III] line wings in stellar supercluster A of NGC 2363 and the turbulent mixing layer hypothesis

Binette

Drissen

Úbeda

et al. 2009

A&A

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“…Supersonic line widths have been observed in many intense star formation sites both in nearby galaxies (30 Dor, Chu & Kennicutt 1994;Melnick et al 1999;NGC 604, Yang et al 1996;NGC 2363, Roy et al 1992González-Delgado et al 1994) and in more distant dwarf galaxies (Izotov et al 1996;Homeier & Gallagher 1999;Marlowe et al 1995;Mendez & Esteban 1997;Sidoli et al 2006;Rozas et al 2006). In these studies, gravitational broadening through virial motions of ionized gas clouds (Melnick 1977;Terlevich & Melnick 1981) and multiple unresolved kinematical components along the line of sight (Chu & Kennicutt 1994) have been proposed as explanations for the broadening of the brightest component (what we refer to as c1).…”

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confidence: 94%

Hubble Space TelescopeSpace Telescope Imaging Spectrograph Spectroscopy of the Environment in the Starburst Core of M82

Westmoquette

Smith

Gallagher

et al. 2007

ApJ

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We present optical HST STIS observations made with two slits crossing four of the optically brightest starburst clumps near the nucleus of M82. These provide H kinematics, extinction, electron density, and emission measures. From the radial velocity curves derived from both slits we confirm the presence of a stellar bar. We derive a new model for the orientation of the bar and disk with respect to the main starburst clumps and the cluster M82-A1. We propose that clump A has formed within the bar region as a result of gas interactions between the bar orbits, whereas region C lies at the edge of the bar and regions D and E are located farther out from the nucleus but heavily obscured. We derive extremely high interstellar densities of 500Y900 cm À3 , corresponding to ISM pressures of P/k % (0:5Y1:0) ; 10 7 cm À3 K, and discuss the implications of the measured gas properties on the production and evolution of the galactic wind. Despite varying pressures, the ionization parameter is uniform down to parsec scales, and we discuss why this might be so. Where the signal-to-noise ratios of our spectra are high enough, we identify multiple emission-line components. Through detailed Gaussian line fitting, we identify a ubiquitous broad (200Y300 km s À1 ) underlying component to the bright H line and discuss the physical mechanism(s) that could be responsible for such widths. We conclude that evaporation and/or ablation of material from interstellar gas clouds caused by the impact of highenergy photons and fast flowing cluster winds produce a highly turbulent layer on the surface of the clouds from which the emission arises.

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“…Modeling of the physical conditions in NGC 2363, based on observations from the literature, has been carried out by Luridiana et al (1999). Using Fabry-Perot and optical spectroscopic observations, Roy et al (1991Roy et al ( , 1992 have discovered an expanding supernova bubble in NGC 2363. There are other H ii regions in NGC 2366 in addition to NGC 2363.…”

Section: Introductionmentioning

confidence: 99%

AHSTStudy of the Stellar Populations in the Cometary Dwarf Irregular Galaxy NGC 2366

Thuan

Izotov

2005

ApJ

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We present Vand I photometry of the resolved stars in the cometary dwarf irregular galaxy NGC 2366, using Wide Field Planetary Camera 2 images obtained with the Hubble Space Telescope. The resulting color-magnitude diagram reaches down to I $ 26:0 mag. It reveals not only a young population of blue main-sequence stars (age P30 Myr) but also an intermediate-age population of blue and red supergiants (20 Myr P age P100 Myr) and older evolved populations of asymptotic giant branch (AGB) stars (age k100 Myr) and red giant branch (RGB) stars (age k1 Gyr). The measured magnitude I ¼ 23:65 AE 0:10 mag of the RGB tip results in a distance modulus m À M ¼ 27:67 AE 0:10, which corresponds to a distance of 3:42 AE 0:15 Mpc, in agreement with previous distance determinations. The youngest stars are associated with the bright complex of H ii regions NGC 2363 (=Mrk 71) in the southwest extremity of the galaxy. As a consequence of the diffusion and relaxation processes of stellar ensembles, the older the stellar population is, the smoother and more extended is its spatial distribution. An underlying population of older stars is found throughout the body of NGC 2366. The most notable feature of this older population is the presence of numerous relatively bright AGB stars. The number ratio of AGB to RGB stars and the average absolute brightness of AGB stars in NGC 2366 are appreciably higher than in the BCD VII Zw 403, indicating a younger age of the AGB stars in NGC 2366. In addition to the present burst of age P100 Myr, there has been strong star formation activity in the past of NGC 2366, from $100 Myr to P3 Gyr ago.

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The origin of broad emission lines in the extragalactic giant H II region NGC 2363

Cited by 54 publications

References 0 publications

The broad Hα, [O III] line wings in stellar supercluster A of NGC 2363 and the turbulent mixing layer hypothesis

The broad Hα, [O III] line wings in stellar supercluster A of NGC 2363 and the turbulent mixing layer hypothesis

Hubble Space TelescopeSpace Telescope Imaging Spectrograph Spectroscopy of the Environment in the Starburst Core of M82

AHSTStudy of the Stellar Populations in the Cometary Dwarf Irregular Galaxy NGC 2366

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