The kinematics of the planetary nebulae in the Large Magellanic Cloud

Meatheringham, S. J.; Dopita, Michael A.; Ford, H. C.; Webster, B. Louise

doi:10.1086/166222

Cited by 103 publications

(92 citation statements)

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“…This method has been applied to various tracers, including H I (Rohlfs et al 1984 ;Luks & Rohlfs 1992 ;Kim et al 1998), star clusters (Freeman et al 1983 ;Schommer et al 1992), planetary nebulae (Meatheringham et al 1988), H II regions and supergiants (Feitzinger et al 1977), and C-rich AGB stars (Kunkel et al 1997 ;Gra † et al 2000 ;. Analysis yields the position angle of the "" kinematic # max line of nodes,ÏÏ deÐned as the line of maximum velocity gradient.…”

Section: T He Kinematic Circular Disk Methodsmentioning

confidence: 99%

“…It seems reasonably well established that the outer geometry of the LMC is indeed planar, as supported by many lines of evidence. These include the following : (1) the small vertical scale height indicated by the small line-of-sight velocity dispersion of long-period variables (Bessell, Freeman, & Wood 1986), star clusters (Freeman, Illingworth, & Oemler 1983 ;Schommer et al 1992), planetary nebulae (Meatheringham et al 1988), and C-rich AGB stars ; (2) the scatter in the period-luminosity-color relationships for Cepheids (Caldwell & Coulson 1986) and Mira variables (Feast et al 1989), which would be larger than observed if the LMC had a signiÐcant scale height ; (3) the kinematics of H I (Luks & Rohlfs 1992 ;Kim et al 1998) and other tracers (e.g., Schommer et al 1992), which are well Ðtted by rotating disk models ; and (4) the fact that other Magellanic irregular galaxies similar to the LMC, some of which are seen close to edge-on, are known to have small scale heights (de Vaucouleurs & Freeman 1973 ;McCall 1993). The actual scale height of the LMC is probably population dependent, but the estimates from the line-of-sight velocity dispersion of tracers in the disk indicate values kpc, possibly [0.5 increasing somewhat in the outer parts of the disk .…”

Section: T He Assumption Of a Planar Geometry For The Outer L Mc Diskmentioning

confidence: 99%

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Magellanic Cloud Structure from Near-Infrared Surveys. I. The Viewing Angles of the Large Magellanic Cloud

Marel¹,

Cioni²

2001

The Astronomical Journal

309

138

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We present a detailed study of the viewing angles of the LMC disk plane. We Ðnd that our viewing direction di †ers considerably from the commonly accepted values, which has important implications for the structure of the LMC. The discussion is based on an analysis of spatial variations in the apparent magnitude of features in the near-IR color-magnitude diagrams extracted from the Deep Near-Infrared Southern Sky Survey (DENIS) and Two Micron All-Sky Survey (2MASS). Sinusoidal brightness variations with a peak-to-peak amplitude of D0.25 mag are detected as a function of position angle. The same variations are detected for asymptotic giant branch stars (using the mode of their luminosity function) and for red giant branch stars (using the tip of their luminosity function), and these variations are seen consistently in all of the near-IR photometric bands in both DENIS and 2MASS data. The observed spatial brightness variations are naturally interpreted as the result of distance variations because of one side of the LMC plane being closer to us than the opposite side. There is no evidence that any complicating e †ects, such as possible spatial variations in dust absorption or the age/metallicity of the stellar population, cause large-scale brightness variations in the near-IR at a level that exceeds the formal errors (D0.03 mag). The best-Ðtting geometric model of an inclined plane yields an inclination angle and line-of-nodes position angle The quoted errors are conservai \ 34¡ .7^6¡ .2 # \ 122¡ .5^8¡ .3. tive estimates that take into account the possible inÑuence of systematic errors ; the formal errors are much smaller, and respectively. There is tentative evidence for variations of D10¡ in the viewing 0¡ .7 1¡ .6, angles with distance from the LMC center, suggesting that the LMC disk plane may be warped. Traditional methods to estimate the position angle of the line of nodes have used either the major-axis position angle of the spatial distribution of tracers on the sky or the position angle of the line of # maj # max maximum gradient in the velocity Ðeld, given that for a circular diskThe present # maj \ # max \ #. study does not rely on the assumption of circular symmetry and is considerably more accurate than previous studies of its kind. We Ðnd that the actual position angle of the line of nodes di †ers considerably from both and for which measurements have fallen in the range 140¡È190¡. This indi-# maj # max , cates that the intrinsic shape of the LMC disk is not circular but elliptical. Paper II of this series explores the implications of this result through a detailed study of the shape and structure of the LMC. The inclination angle inferred here is consistent with previous estimates, but this is to some extent a coincidence, given that also for the inclination angle most previous estimates were based on the incorrect assumption of circular symmetry.

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Section: T He Kinematic Circular Disk Methodsmentioning

confidence: 99%

Section: T He Assumption Of a Planar Geometry For The Outer L Mc Diskmentioning

confidence: 99%

Magellanic Cloud Structure from Near-Infrared Surveys. I. The Viewing Angles of the Large Magellanic Cloud

Marel¹,

Cioni²

2001

The Astronomical Journal

309

138

View full text Add to dashboard Cite

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“…Two thorough investigations (Meatheringham et al 1988;Luks & Rohlfs 1992) document that the radial rotation curve has an amplitude of ∼ 60 km s −1 . The lateral motion of the LMC was recently derived by Kroupa & Bastian (1997) from an analysis of proper motion measurements of stars in the field of the LMC by Hipparcos.…”

Section: Velocity Rotation and Inclination Of The Lmcmentioning

confidence: 99%

Bow Shock Induced Star Formation in the LMC

Boer

Braun²,

Vallenari³

et al. 1999

Symp. - Int. Astron. Union

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Abstract. The structure of supergiant shells, in particular of LMC 4, is hard to explain with stochastic selfpropagating star formation. A series of supergiant structures lies along the outer edge of the LMC and form a sequence increasing clockwise in age. We have considered the rotation of the LMC and its motion through the halo of the Milky Way and propose that these structures find their origin in star formation induced in the bow-shock formed at the leading edge of the LMC. Due to the rotation of the LMC these structures then move aside.

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“…The proper motion for the LMC is an average of three studies : Jones, Klemola, & Lin (1994), Kroupa, & Roser, Bastian (1994), and Kroupa & Bastian (1997). The adopted heliocentric distance to the LMC is 49^5 kpc, and the heliocentric radial velocity is 270^4 km s~1 (see, e.g., Kroupa & Bastian 1997 ;Meatheringham et al 1988). Two proper-motion determinations are presented for Sgr : the one derived by Irwin et al (1996) from Schmidt plates (Sgr 1), and the one derived by Ibata, Irwin, & Lewis (2001) from HST WFPC2 frames (Sgr 2) and quoted in Irwin (1998).…”

Section: Orbit T Ypes Of Globular Clusters and Galactic Satellitesmentioning

confidence: 99%

Orbits of Globular Clusters in the Outer Galaxy: NGC 7006

Dinescu

Majewski

Girard

et al. 2001

The Astronomical Journal

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We present a proper-motion study of the distant globular cluster NGC 7006 based on the measurement of 25 photographic plates spanning a 40 yr interval. The absolute proper motion determined with respect to extragalactic objects is [1.14)^(0.35, 0.40) mas yr~1. The total space96, velocity of NGC 7006 in a Galactocentric rest frame is 279 km s~1, placing the cluster on one of the most energetic orbits kpc) known to date for clusters within 40 kpc from the Galactic center. (R a \ 102 We compare the orbitsÈas determined from full space velocitiesÈof four clusters that have apocentric radii larger than 80 kpc with those of Galactic satellites with well-measured proper motions. These clusters are NGC 5466, 6934, and 7006 and Pal 13, and the satellites are the Sagittarius dwarf spheroidal galaxy (dSph), the Large Magellanic Cloud, the Ursa Minor dSph, and the Sculptor dSph. Only NGC 5466 and 6934 seem to have similar orbital parameters, indicating a possible phase-space association. NGC 7006, Pal 13, and the "" pair ÏÏ NGC 5466 and 6934 do not show any dynamical association with the Galactic satellites considered here. NGC 5466, 6934, and 7006 and Pal 13 have orbits that are highly eccentric and of various inclinations with respect to the Galactic plane. In contrast, the orbits of the Galactic satellites are of low to moderate eccentricity and highly inclined. Based on orbit types, chemical abundances, and cluster parameters, we discuss the properties of the hypothetical host systems of the remote globular clusters in the Searle-Zinn paradigm. It is apparent that clusters such as NGC 5466, 6934, and 7006 formed in systems that more likely resemble the Fornax dSph rather than the Sagittarius dSph. We also discuss plausible causes for the di †erence found so far between the orbit type of outer halo clusters and that of Galactic satellites and for the tentative, yet suggestive, phase-space scatter found among outer halo clusters.

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The kinematics of the planetary nebulae in the Large Magellanic Cloud

Cited by 103 publications

References 0 publications

Magellanic Cloud Structure from Near-Infrared Surveys. I. The Viewing Angles of the Large Magellanic Cloud

Magellanic Cloud Structure from Near-Infrared Surveys. I. The Viewing Angles of the Large Magellanic Cloud

Bow Shock Induced Star Formation in the LMC

Orbits of Globular Clusters in the Outer Galaxy: NGC 7006

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