Properties of barred spiral galaxies

Elmegreen, Bruce G.; Elmegreen, D. M.

doi:10.1086/162810

Cited by 316 publications

(414 citation statements)

References 0 publications

Supporting

Mentioning

360

Contrasting

Order By: Relevance

“…Some of these, particularly in the western arm, form a structure that resembles "beads on a string", which is usually associated with large scale gravitational instabilities along the arms. Our findings agree, thus, with the hypothesis of turbulence-driven hierarchical star formation across galactic scales as has been previously observed with LEGUS from UV images (Elmegreen et al 2014b), resolved stellar populations (Gouliermis et al 2015a), and stars clusters (Grasha et al 2015) in various nearby galaxies. These studies provide evidence that galaxy-wide star formation is organized by large-scale gravitational processes in a pattern analogous to the turbulent self-similar galactic ISM structure.…”

Section: Discussionsupporting

confidence: 92%

Hierarchical star formation across the grand-design spiral NGC 1566

Gouliermis

Elmegreen²,

Elmegreen

et al. 2017

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We investigate how star formation is spatially organized in the grand-design spiral NGC 1566 from deep HST photometry with the Legacy ExtraGalactic UV Survey (LEGUS). Our contour-based clustering analysis reveals 890 distinct stellar conglomerations at various levels of significance. These star-forming complexes are organized in a hierarchical fashion with the larger congregations consisting of smaller structures, which themselves fragment into even smaller and more compact stellar groupings. Their size distribution, covering a wide range in length-scales, shows a power-law as expected from scale-free processes. We explain this shape with a simple "fragmentation and enrichment" model. The hierarchical morphology of the complexes is confirmed by their mass-size relation which can be represented by a powerlaw with a fractional exponent, analogous to that determined for fractal molecular clouds. The surface stellar density distribution of the complexes shows a log-normal shape similar to that for supersonic non-gravitating turbulent gas. Between 50 and 65 per cent of the recentlyformed stars, as well as about 90 per cent of the young star clusters, are found inside the stellar complexes, located along the spiral arms. We find an age-difference between young stars inside the complexes and those in their direct vicinity in the arms of at least 10 Myr. This timescale may relate to the minimum time for stellar evaporation, although we cannot exclude the in situ formation of stars. As expected, star formation preferentially occurs in spiral arms. Our findings reveal turbulent-driven hierarchical star formation along the arms of a grand-design galaxy.

show abstract

Section: Discussionsupporting

confidence: 92%

Hierarchical star formation across the grand-design spiral NGC 1566

Gouliermis

Elmegreen²,

Elmegreen

et al. 2017

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…In contrast, galaxies like NGC 2500 and NGC 1359 show small weak central bars in disks with very little spiral structure of any kind. Previously, we showed that the bars in early Hubble types (taken here to be SBa-SBbc) have B and / light profiles which are approximately constant along the bars ("flat" bars; Elmegreen & Elmegreen 1985). Galaxies in later Hubble types (SBc-SBm) have light profiles which decrease with a scale length virtually indistinguishable from that of the disk ("exponential" bars).…”

Section: Bar Size and Type Versus Hubble Typementioning

confidence: 94%

Bar Properties as a Function of Hubble Type

Elmegreen

1996

International Astronomical Union Colloquium

View full text Add to dashboard Cite

Abstract. Previous optical surface photometry of barred spiral galaxies revealed that there are two distinct types of bars: large bars tend to have a nearly constant surface brightness ("flat" bar), while smaller bars tend to have a decreasing surface brightness with a scale length similar to the disk ("exponential" bar). Statistically, flat bars tend to occur in early Hubble types and exponential bars in later types. Studies of resonances in spirals indicate that flat bars end inside corotation, while exponential bars end between the inner Lindblad and 4:1 resonances. Near-infrared (JHK) surface photometry of bars is presented in order to compare the stellar distributions and bar potentials in flat and exponential barred galaxies. The presence of isophotal twists in some galaxies provides additional information on resonances. The grand design and fiocculent optical structures in the two types of barred galaxies will be compared and contrasted with their near-infrared light distributions.

show abstract

“…In the late-type barred galaxies, the situation is quite different: the slopes of the profiles in the bar regions are larger than those in the outer disks and no cut off is seen at the bar ends. The presence of these two types of bars, that is, flat bar and exponential bar, was first noticed by Elmegreen & Elmegreen (1985) when they examined the profiles along bars and spiral arms. The flat bars tend to reside in early-type galaxies and exponential bars in late-type galaxies.…”

Section: Azimuthal Profilesmentioning

confidence: 98%

“…There are two parameters, c and -; they may be good indicators of discriminating morphology between barred galaxies and unbarred galaxies. Elmegreen & Elmegreen(1985) proposed a clear method of defining the luminosity fraction of a bar. They defined it using the amplitudes of the Fourier components of the azimuthal profiles as (I2 -I^)/IQ.…”

Section: Luminosity Distribution Of a Barmentioning

confidence: 99%

“…Until the seventies, there had been only several barred galaxies which were studied in detail (e.g., Crane 1975;Benedict 1976;Okamura & Takase 1976;Okamura 1978). In the eighties and the nineties, detailed surface photometry of barred galaxies was made extensively (e.g., Blackman 1983;Duval & Athanassoula 1983;Duval & Monnet 1985;Elmegreen & Elmegreen 1985;Pence & de Vaucouleurs 1985;Buta 1986Buta , 1987Ann 1986;Baumgart & Peterson 1986;Ohta, Hamabe, & Wakamatsu 1990;Odewahn 1991;Wozniak & Pierce 1991). In this review I present properties of the surface brightness distribution of barred galaxies mainly based on our work.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation