SDSS-IV MaNGA: the inner density slopes of nearby galaxies

Journal Article · 13 September 2019 · Monthly Notices of the Royal Astronomical Society

DOI: https://doi.org/10.1093/mnras/stz2565 · OSTI ID:1571323

Li, Ran  ^[1]; Li, Hongyu ^[1]; Shao, Shi  ^[2]; Lu, Shengdong ^[3]; Zhu, Kai ^[3]; Wang, Chunxiang ^[3]; Gao, Liang ^[4]; Mao, Shude ^[5]; Dutton, Aaron A.  ^[6]; Ge, Junqiang ^[7]; Wang, Yunchong  ^[8]; Leauthaud, Alexie  ^[9]; Zheng, Zheng ^[7]; Bundy, Kevin ^[9]; Brownstein, Joel R.  ^[10]

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1. National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012, China, Key laboratory for Computational Astrophysics, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China, School of Astronomy and Space Science, University of Chinese Academy of Science, Beijing 100049, China
2. Institute for Computational Cosmology, Department of Physics, University of Durham, South Road, Durham DH1 3LE, UK
3. National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012, China, Key laboratory for Computational Astrophysics, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China
4. National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012, China, Key laboratory for Computational Astrophysics, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China, School of Astronomy and Space Science, University of Chinese Academy of Science, Beijing 100049, China, Institute for Computational Cosmology, Department of Physics, University of Durham, South Road, Durham DH1 3LE, UK
5. Physics Department and Tsinghua Centre for Astrophysics, Tsinghua University, Beijing 100084, China, National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012, China
6. New York University Abu Dhabi, PO Box 129188, Abu Dhabi, United Arab Emirates
7. National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012, China
8. Physics Department and Tsinghua Centre for Astrophysics, Tsinghua University, Beijing 100084, China
9. Department of Astronomy and Astrophysics, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
10. Department of Physics and Astronomy, University of Utah, 115 S. 1400 E., Salt Lake City, UT 84112, USA

ABSTRACT We derive the mass-weighted total density slopes within the effective (half-light) radius, γ′, for more than 2000 nearby galaxies from the SDSS-IV (Sloan Digital Sky Survey IV) MaNGA survey using Jeans-anisotropic-models applied to integral field unit observations. Our galaxies span a wide range of the stellar mass (109 M⊙ < M* < 1012 M⊙) and the velocity dispersion (30 km s−1 < σv < 300 km s−1). We find that for galaxies with velocity dispersion σv > 100 km s−1, the density slope has a mean value 〈γ′〉 = 2.24 and a dispersion σγ = 0.22, almost independent of velocity dispersion, consistent with previous lensing and stellar dynamical analysis. We also quantitatively confirm with high accuracy a turnover in the γ′–σv relation is present at σ ∼ 100 km s−1, below which the density slope decreases rapidly with σv, consistent with the results reported by previous analysis of $${\rm ATLAS^{\rm 3D}}$$ survey. Our analysis shows that a large fraction of dwarf galaxies (below M* = 1010 M⊙) have total density slopes shallower than 1, which implies that they may reside in cold dark matter haloes with shallow density slopes. We compare our results with that of galaxies in hydrodynamical simulations of EAGLE, Illustris, and IllustrisTNG projects, and find all simulations predict shallower density slopes for massive galaxies with high σv. Finally, we explore the dependence of γ′ on the positions of galaxies in haloes, namely centrals versus satellites, and find that for the same velocity dispersion, the amplitude of γ′ is higher for satellite galaxies by about 0.1.

• Sponsoring Organization: USDOE
• OSTI ID: 1571323
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Vol. 490 Journal Issue: 2; ISSN 0035-8711
• Publisher: Oxford University PressCopyright Statement
• Country of Publication: United Kingdom
• Language: English