THE STRUCTURE AND STELLAR CONTENT OF THE OUTER DISKS OF GALAXIES: A NEW VIEW FROM THE Pan-STARRS1 MEDIUM DEEP SURVEY

Zheng, Zheng; Thilker, David A.; Heckman, T.; Meurer, G. R.; Burgett, W. S.; Chambers, K.; Huber, M.; Kaiser, N.; Magnier, E. A.; Metcalfe, N.; Price, P. A.; Tonry, J.; Wainscoat, R. J.; Waters, C.

doi:10.1088/0004-637x/800/2/120

Cited by 49 publications

(82 citation statements)

References 68 publications

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“…This is in agreement with the results of Roškar et al (2008) presenting simulations with a downbending disc profile induced by a star formation threshold and outward migration, and with observations e.g. in Radburn-Smith et al (2012) and Zheng et al (2015), and thus adds a further argument to those presented in A16 that the remnant of a major merger is a disc galaxy and behaves in all aspects as such.…”

Section: Migration and Angular Momentumsupporting

confidence: 92%

Forming disc galaxies in major mergers – III. The effect of angular momentum on the radial density profiles of disc galaxies

Peschken

Athanassoula

Родионов

2017

Monthly Notices of the Royal Astronomical Society

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We study the effect of angular momentum on the surface density profiles of disc galaxies, using high resolution simulations of major mergers whose remnants have downbending radial density profiles (type II). As described in the previous papers of this series, in this scenario, most of the disc mass is acquired after the collision via accretion from a hot gaseous halo. We find that the inner and outer disc scalelengths, as well as the break radius, correlate with the total angular momentum of the initial merging system, and are larger for high angular momentum systems. We follow the angular momentum redistribution in our simulated galaxies, and find that, like the mass, the disc angular momentum is acquired via accretion, i.e. to the detriment of the gaseous halo. Furthermore, high angular momentum systems give more angular momentum to their discs, which affects directly their radial density profile. Adding simulations of isolated galaxies to our sample, we find that the correlations are valid also for disc galaxies evolved in isolation. We show that the outer part of the disc at the end of the simulation is populated mainly by inside-out stellar migration, and that in galaxies with higher angular momentum, stars travel radially further out. This, however, does not mean that outer disc stars (in type II discs) were mostly born in the inner disc. Indeed, generally the break radius increases over time, and not taking this into account leads to overestimating the number of stars born in the inner disc.

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Section: Migration and Angular Momentumsupporting

confidence: 92%

Forming disc galaxies in major mergers – III. The effect of angular momentum on the radial density profiles of disc galaxies

Peschken

Athanassoula

Родионов

2017

Monthly Notices of the Royal Astronomical Society

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“…Similar age or colour gradient turnover have been noted for local galaxies (e.g. Bakos et al 2008;Radburn-Smith et al 2012;D'Souza et al 2014;Zheng et al 2015). Also Wuyts et al (2012) finds disks with older stellar ages in the outskirts at z ∼ 1.…”

Section: Basic Findings On Stacked Colour Gradientssupporting

confidence: 77%

UVI colour gradients of 0.4 < z < 1.4 star-forming main-sequence galaxies in CANDELS: dust extinction and star formation profiles

Wang

Faber

Liu

et al. 2017

Monthly Notices of the Royal Astronomical Society

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This paper uses radial colour profiles to infer the distributions of dust, gas and star formation in z = 0.4-1.4 star-forming main sequence galaxies. We start with the standard UVJ -based method to estimate dust extinction and specific star formation rate (sSFR). By replacing J with I band, a new calibration method suitable for use with ACS+WFC3 data is created (i.e. UVI diagram). Using a multi-wavelength multiaperture photometry catalogue based on CANDELS, UVI colour profiles of 1328 galaxies are stacked in stellar mass and redshift bins. The resulting colour gradients, covering a radial range of 0.2-2.0 effective radii, increase strongly with galaxy mass and with global A V . Colour gradient directions are nearly parallel to the Calzetti extinction vector, indicating that dust plays a more important role than stellar population variations. With our calibration, the resulting A V profiles fall much more slowly than stellar mass profiles over the measured radial range. sSFR gradients are nearly flat without central quenching signatures, except for M > 10 10.5 M , where central declines of 20-25 per cent are observed. Both sets of profiles agree well with previous radial sSFR and (continuum) A V measurements. They are also consistent with the sSFR profiles and, if assuming a radially constant gas-to-dust ratio, gas profiles in recent hydrodynamic models. We finally discuss the striking findings that SFR scales with stellar mass density in the inner parts of galaxies, and that dust content is high in the outer parts despite low stellar-mass surface densities there.

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“…However, comparisons to observation are complicated by the fact that observed profiles can be different in different wavebands, e.g., due to stellar population gradients (e.g., Bakos, et al 2008, Herrmann, et al 2013, Zheng, et al 2015. Also there may be radial variations in mass-to-light ratios, so mass and light profiles may differ (Zheng, et al 2015). Azimuthal velocity and velocity dispersion profiles will help constrain combinations of the exponents and the factor χ1.…”

Section: Examples With More Complex (Sérsic-type)mentioning

confidence: 99%

“…The early observations did not extend to very faint surface brightnesses, nor over many scale lengths. Recent observations have gone much deeper (e.g., Bland-Hawthorn, et al 2005Gadotti 2009, Erwin, et al 2005, Pohlen & Trujillo 2006, Herrmann, et al 2013, and Zheng, et al 2015, showing the continuation of exponential form over about 10 scale lengths in some cases. As originally noted by Freeman (1970) the radial profiles often have a break, either turning downward in the outer parts (Type II) or upward (Type III) (also see Erwin, et al 2005, Pohlen & Trujillo 2006, Herrmann, et al 2013).…”

Section: Introductionmentioning

confidence: 98%

Near-exponential surface densities as hydrostatic, non-equilibrium profiles in galaxy discs

Struck

Elmegreen

2016

Mon. Not. R. Astron. Soc.

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Apparent exponential surface density profiles are nearly universal in galaxy discs across Hubble types, over a wide mass range, and a diversity of gravitational potential forms. Several processes have been found to produce exponential profiles, including the actions of bars and spirals, and clump scattering, with star scattering a common theme in these. Based on reasonable physical constraints, such as minimal entropy gradients, we propose steady state distribution functions for disc stars, applicable over a range of gravitational potentials. The resulting surface density profiles are generally a power-law term times a Sérsic-type exponential. Over a modest range of Sérsic index values, these profiles are often indistinguishable from Type I exponentials, except at the innermost radii. However, in certain parameter ranges these steady states can appear as broken, Type II or III profiles. The corresponding velocity dispersion profiles are low order power-laws. A chemical potential associated with scattering can help understand the effects of long range scattering. The steady profiles are found to persist through constant velocity expansions or contractions in evolving discs. The proposed distributions and profiles are simple and solve the stellar hydrodynamic equations. They may be especially relevant to thick discs, which have settled to a steady form via scattering.

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THE STRUCTURE AND STELLAR CONTENT OF THE OUTER DISKS OF GALAXIES: A NEW VIEW FROM THE Pan-STARRS1 MEDIUM DEEP SURVEY

Cited by 49 publications

References 68 publications

Forming disc galaxies in major mergers – III. The effect of angular momentum on the radial density profiles of disc galaxies

Forming disc galaxies in major mergers – III. The effect of angular momentum on the radial density profiles of disc galaxies

UVI colour gradients of 0.4 < z < 1.4 star-forming main-sequence galaxies in CANDELS: dust extinction and star formation profiles

Near-exponential surface densities as hydrostatic, non-equilibrium profiles in galaxy discs

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