Galaxy Disks

By P. Kruit, Kenneth C. Freeman. 2011

197 citations recorded by the source corpus.

The disks of disk galaxies contain a substantial fraction of their baryonic matter and angular momentum, and much of the evolutionary activity in these galaxies, such as the formation of stars, spiral arms, bars and rings and the various forms of secular evolution, takes place in their disks. The formation and evolution of galactic disks is therefore particularly important for understanding how galaxies form and evolve, and the cause of the variety in which they appear to us. Ongoing large surveys, made possible by new instrumentation at wavelengths from the ultraviolet (GALEX), via optical (HST and large groundbased telescopes) and infrared (Spitzer) to the radio are providing much new information about disk galaxies over a wide range of redshift. Although progress has been made, the dynamics and structure of stellar disks, including their truncations, are still not well understood. We do now have plausible estimates of disk mass-to-light ratios, and estimates of Toomre’s Q parameter show that they are just locally stable. Disks are mostly very flat and sometimes very thin, and have a range in surface brightness from canonical disks with a central surface brightness of about 21.5 B-mag arcsec−2 down to very low surface brightnesses. It appears that galaxy disks are not maximal, except possibly in the largest systems. Their HI layers display warps whenever HI can be detected beyond the stellar disk, with low-level star formation going on out to large radii. Stellar disks display abundance gradients which flatten at larger radii and sometimes even reverse. The existence of a well-defined baryonic (stellar + HI) Tully-Fisher relation hints at an approximately uniform baryonic to dark matter ratio. Thick disks are common in disk galaxies and their existence appears unrelated to the presence of a bulge component; they are old, but their formation is not yet understood. Disk formation was already advanced at redshifts of ∼ 2, but at that epoch disks were not yet quiescent and in full rotational equilibrium. Downsizing (the gradual reduction with time in the mass of the most actively star-forming galaxies) is now well-established. The formation and history of star formation in S0s is still not fully understood. The final version of this chapter as it will appear in Annual Reviews of Astronomy & Astrophysics, vol. 49 (2011), will have fewer figures and a somewhat shortened text. 1 ar X iv :1 10 1. 17 71 v3 [ as tr oph .G A ] 1 3 Ja n 20 11

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/419bd51781a48b4f71e1b0b28dbb7ae47b583874

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Citations in the corpus

DOES THE STELLAR DISTRIBUTION FLARE? A COMPARISON OF STELLAR SCALE HEIGHTS WITH LAB H i DATA (2014, background): “This, however, is hard to understand physically since the radial decrease in surface density needs to be precisely compensated by the fall-off of the stellar vertical velocity dispersion σz (van der Kruit & Freeman 2011, see Section 3.2.3 for discussion).”
The Evolution of Galaxy Structure Over Cosmic Time (2014, background): “For nearby galaxy’s a few recent relevant reviews are Blanton & Moustakas (2009), van der Kruit & Freeman (2011), and Conroy (2013).”
Galaxy Masses: A Review (2013, background): “…show spiral arm features, truncations, anti-truncations, and other deviations from a pure exponential surface density distribution (see e.g. van der Kruit & Freeman 2011) that are best modeled through a free form reconstruction of the stellar mass by inversion of the light profile as discussed…”
One Law to Rule Them All: The Radial Acceleration Relation of Galaxies (2016, background): “…2016), late-type galaxies (LTGs) like spirals and irregulars (e.g., Rubin et al. 1985; van Albada & Sancisi 1986; Persic & Salucci 1991; van der Kruit & Freeman 2011), and dwarf spheroidals (dSphs) in the Local Group (e.g., Mateo 1998; Battaglia et al. 2008; Strigari et al. 2008; Walker et al.…”
A REVISED PARALLEL-SEQUENCE MORPHOLOGICAL CLASSIFICATION OF GALAXIES: STRUCTURE AND FORMATION OF S0 AND SPHEROIDAL GALAXIES (2011, background): “Second, the outer disk of NGC 4452 is warped and thicker than the “superthin” edge-on, late-type galaxies seen in isolated environments (van der Kruit & Freeman 2011).”
THE UNIVERSAL RELATION OF GALACTIC CHEMICAL EVOLUTION: THE ORIGIN OF THE MASS–METALLICITY RELATION (2014, background): “Galaxies have gas disks that extend well beyond their stellar and star-forming disks (van der Kruit & Freeman 2011).”
Idealized models for galactic disc formation and evolution in ‘realistic’ ΛCDM haloes (2012, background): “…is general agreement on the formation and structure of dark matter haloes in CDM (e.g. Springel et al. 2008), and on the observational side, a detailed picture of the structure of disc galaxies has been assembled over the last few decades (see van der Kruit & Freeman 2011 for a recent review).”
The Milky Way’s stellar disk (2013, background): “For its stellar mass, the structural parameters of the Disk are also not exceptional (e.g., van der Kruit & Freeman 2011).”
Mapping the Milky Way with LAMOST– III. Complicated spatial structure in the outer disc (2018, methodology): “In the vertical direction, an alternative sech2 form is also freguently used as the density profile model (van der Kruit 1988; van der Kruit & Freeman 2011).”
INSIDE OUT AND UPSIDE DOWN: TRACING THE ASSEMBLY OF A SIMULATED DISK GALAXY USING MONO-AGE STELLAR POPULATIONS (2013, background): “In the same model galaxy, the vertical velocity dispersion of an isothermal, non-migrating population also scales with disk surface density but has an additional dependence on the scale height of the population as a function of radius (hz), i.e., σvz,non ∝ √ Σhz (e.g., van der Kruit & Freeman 2011).”
Radial migration does little for Galactic disc thickening (2012, background): “7 by van der Kruit and Freeman 2011).”
The Galaxy in Context: Structural, Kinematic, and Integrated Properties (2016, background): “For the past thirty years, some have argued for a longer disk scale length when comparing the Galaxy, with its high mass and luminosity, with external galaxies (q.v. van der Kruit & Freeman 2011).”
Theoretical Challenges in Galaxy Formation (2016, background): “…density profile (de Vaucouleurs 1948) and a flattened, rotationally supported disk/spiral component, which is typically somewhat larger (apart from the highest mass systems) and has a roughly exponential profile (e.g. Blanton & Moustakas 2009, Shen et al. 2003, van der Kruit & Freeman 2011).”