Assessing the Jeans Anisotropic Multi-Gaussian Expansion method with the Illustris simulation

Quiescent galaxies with little or no ongoing star formation dominate the galaxy population above M * ∼ 2 × 10 10 M⊙, where their numbers have increased by a factor of ∼ 25 since z ∼ 2 1-4 . Once star formation is initially shut down, perhaps during the quasar phase of rapid accretion onto a supermassive black hole [5][6][7] , an unknown mechanism must remove or heat subsequently accreted gas from stellar mass loss 8 or mergers that would otherwise cool to form stars 9, 10 . Energy output from a black hole accreting at a low rate has been proposed 11-13 , but observational evidence for this in the form of expanding hot gas shells is indirect and limited to radio galaxies at the centers of clusters 14,15 , which are too rare to explain the vast majority of the quiescent population 16 . Here we report bisymmetric emission features co-aligned with strong ionized gas velocity gradients from which we infer the presence of centrallydriven winds in typical quiescent galaxies that host low-luminosity active nuclei. These galaxies are surprisingly common, accounting for as much as 10% of the population at M * ∼ 2 × 10 10 M⊙. In a prototypical example, we calculate that the energy input from the galaxy's low-level active nucleus is capable of driving the observed wind, which contains sufficient mechanical energy to heat ambient, cooler gas (also detected) and thereby suppress star formation.Using optical imaging spectroscopy from the Sloan Digital Sky Survey-IV Mapping Nearby Galaxies at Apache Point Observatory 17 (SDSS-IV MaNGA) program, we define a new class of quiescent galaxies (required to have red rest-frame colors, NUV − r > 5) that is characterized by the presence of narrow bisymmetric patterns in equivalent width (EW) maps of strong emission lines, such as Hα and [O III]. Our selection employs multiband imaging to exclude galaxies with dust lanes and other disk signatures. The observed enhanced emission features are oriented randomly with respect to the optical surface brightness morphology, but roughly align with strong, systematic velocity gradients as traced by the ionized gas emission lines. The gas velocity fields in these galaxies are decoupled from their stellar motions. These galaxies are surprisingly common among the quiescent population, accounting for ∼10% of quiescent galaxies with log M * /M⊙ ∼ 10.3. To illuminate the salient features of this class, we focus on a prototypical example, nicknamed "Akira" (Fig. 1). The SDSS imaging shows Akira to be an unremarkable spheroidal galaxy of moderate stellar mass (log M * /M⊙ = 10.78) that is interacting with a low-mass companion (nicknamed "Tetsuo") at a projected separation of ≈ 32 kpc (67 ′′ ); they are not classified as members of a larger galaxy group 18 and the properties of both galaxies are listed in Table 1. Spectral energy distribution (SED) fitting indicates that Akira is nearly dormant, with almost no detection of ongoing star formation 19 . Resolved spectroscopy, however, reveals intriguing and complex patterns among spectral tracers of gas in Ak...

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“…Although there is some covariance between the model parameters, the resulting total mass profile, is extremely robust 50 .…”

Section: Methodsmentioning

confidence: 99%

Suppressing star formation in quiescent galaxies with supermassive black hole winds

Cheung

Bundy

Cappellari

et al. 2016

Nature

191

256

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“…Among 562 elliptical galaxies observed in the first year, 160 are rejected due to one offour reasons: many pixels having unphysical velocity dispersion (38), having fewer than 20 Voronoi bins (51), having a foreground star (12), orbeing a merger or in a close pair (59). Among the remaining 402 galaxies, we run JAM within aMarkov chain Monte Carlo (MCMC) framework, as described by Li et al (2016). From these, we estimated the statistical uncertainty on the enclosed gravitating mass and the dark matter fraction, using the 1D marginalized MCMC distributions.…”

Section: Enclosed Gravitating Mass and Dark Matter Fractionmentioning

confidence: 99%

Section: Enclosed Gravitating Mass and Dark Matter Fractionmentioning

confidence: 99%

“…In light of the recent work by Li et al (2016), it is apparent that these random errors are dwarfed by the systematic error associated with the JAM method. Li et al (2016) evaluated the accuracy of the JAM method using simulated galaxies from the Illustrius project (Genel et al 2014;Nelson et al 2015). They found that, with a 0.5 kpc imaging resolution and 2 kpc velocity field resolution, the true fractional uncertainty is 11%-16% on the total massand ∼33% on the dark matter mass within 2.5R e , with relatively little bias (3%) in the median value.…”

Section: Enclosed Gravitating Mass and Dark Matter Fractionmentioning

confidence: 99%

See 1 more Smart Citation

SDSS-IV MaNGA IFS GALAXY SURVEY—SURVEY DESIGN, EXECUTION, AND INITIAL DATA QUALITY

Yan

Bundy

Law

et al. 2016

Self Cite

334

161

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The MaNGA Survey (Mapping Nearby Galaxies at Apache Point Observatory) is one of three core programs in the Sloan Digital Sky Survey IV. It is obtaining integral field spectroscopy for 10,000nearby galaxies at a spectral resolution of R∼2000 from 3622 to 10354 Å. The design of the survey is driven by a set of science requirements on the precision of estimates of the following properties: star formation rate surface density, gas metallicity, stellar population age, metallicity, and abundance ratio, and their gradients; stellar and gas kinematics; and enclosed The Astronomical Journal, 152:197 (32pp) 1 gravitational mass as a function of radius. We describe how these science requirements set the depth of the observations and dictate sample selection. The majority of targeted galaxies are selected to ensure uniform spatial coverage in units of effective radius (R e ) while maximizing spatial resolution. About two-thirds of the sample is covered out to 1.5R e (Primary sample), and one-thirdof the sample is covered to 2.5R e (Secondary sample). We describe the survey execution with details that would be useful in the design of similar future surveys. We also present statistics on the achieved data quality, specificallythe point-spread function, sampling uniformity, spectral resolution, sky subtraction, and flux calibration. For our Primary sample, the median r-band signal-to-noise ratio is ∼70 per 1.4 Å pixel for spectra stacked between 1R e and 1.5R e . Measurements of various galaxy properties from the first-year data show that we are meeting or exceeding the defined requirements for the majority of our science goals.

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“…The ability of axisymmetric Jeans models to recover the mass profile and velocity anisotropy of different types of galaxies has already been established statistically with thousands of simulated galaxies in Li et al (2016). We focus on testing how well we are able to distinguish two chemically and kinematically distinct populations from discrete data, while simultaneously recovering the underlying gravitational potential.…”

Section: Application To Mock Datamentioning

confidence: 99%

A discrete chemo-dynamical model of the dwarf spheroidal galaxy Sculptor: mass profile, velocity anisotropy and internal rotation

Zhu

Ven

Watkins³

et al. 2016

Mon. Not. R. Astron. Soc.

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We present a new discrete chemo-dynamical axisymmetric modeling technique, which we apply to the dwarf spheroidal galaxy Sculptor. The major improvement over previous Jeans models is that realistic chemical distributions are included directly in the dynamical modelling of the discrete data. This avoids loss of information due to spatial binning and eliminates the need for hard cuts to remove contaminants and to separate stars based on their chemical properties. Using a combined likelihood in position, metallicity and kinematics, we find that our models naturally separate Sculptor stars into a metal-rich and a metal-poor population. Allowing for non-spherical symmetry, our approach provides a central slope of the dark matter density of γ = 0.5 ± 0.3. The metal-rich population is nearly isotropic (with β red r = 0.0 ± 0.1) while the metal-poor population is tangentially anisotropic (with β blue r = −0.2 ± 0.1) around the half light radius of 0.26 kpc. A weak internal rotation of the metal-rich population is revealed with v max /σ 0 = 0.15 ± 0.15. We run tests using mock data to show that a discrete dataset with ∼ 6000 stars is required to distinguish between a core (γ = 0) and cusp (γ = 1), and to constrain the possible internal rotation to better than 1 σ confidence with our model. We conclude that our discrete chemo-dynamical modelling technique provides a flexible and powerful tool to robustly constrain the internal dynamics of multiple populations, and the total mass distribution in a stellar system.

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Assessing the Jeans Anisotropic Multi-Gaussian Expansion method with the Illustris simulation

Cited by 61 publications

References 59 publications

Suppressing star formation in quiescent galaxies with supermassive black hole winds

Suppressing star formation in quiescent galaxies with supermassive black hole winds

SDSS-IV MaNGA IFS GALAXY SURVEY—SURVEY DESIGN, EXECUTION, AND INITIAL DATA QUALITY

A discrete chemo-dynamical model of the dwarf spheroidal galaxy Sculptor: mass profile, velocity anisotropy and internal rotation

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