SDSS IV MaNGA: full spectroscopic bulge-disc decomposition of MaNGA early-type galaxies

Tabor, Martha; Merrifield, Michael; Arag�n-Salamanca, Alfonso; Fraser-Mckelvie, Amelia; Peterken, Thomas; Smethurst, Rebecca; Drory, Niv; Lane, Richard R.

Abstract

By applying spectroscopic decomposition methods to a sample of MaNGA early-type galaxies, we separate out spatially and kinematically distinct stellar populations, allowing us to explore the similarities and differences between galaxy bulges and discs, and how they affect the global properties of the galaxy. We find that the components have interesting variations in their stellar populations, and display different kinematics. Bulges tend to be consistently more metal rich than their disc counterparts, and while the ages of both components are comparable, there is an interesting tail of younger, more metal-poor discs. Bulges and discs follow their own distinct kinematic relationships, both on the plane of the stellar spin parameter, λR, and ellipticity, ϵ, and in the relation between stellar mass, M*, and specific angular momentum, j*, with the location of the galaxy as a whole on these planes being determined by how much bulge and disc it contains. As a check of the physical significance of the kinematic decompositions, we also dynamically model the individual galaxy components within the global potential of the galaxy. The resulting components exhibit kinematic parameters consistent with those from the spectroscopic decomposition, and though the dynamical modelling suffers from some degeneracies, the bulges and discs display systematically different intrinsic dynamical properties. This work demonstrates the value in considering the individual components of galaxies rather than treating them as a single entity, which neglects information that may be crucial in understanding where, when, and how galaxies evolve into the systems we see today.

Citation

Tabor, M., Merrifield, M., Aragón-Salamanca, A., Fraser-Mckelvie, A., Peterken, T., Smethurst, R., …Lane, R. R. (2019). SDSS IV MaNGA: full spectroscopic bulge-disc decomposition of MaNGA early-type galaxies. Monthly Notices of the Royal Astronomical Society, 485(2), 1546–1558. https://doi.org/10.1093/mnras/stz431

• Journal Article Type: Article
• Acceptance Date: Feb 8, 2019
• Online Publication Date: Feb 13, 2019
• Publication Date: May 11, 2019
• Deposit Date: Feb 13, 2019
• Publicly Available Date: Feb 13, 2019
• Journal: MNRAS
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 485
• Issue: 2
• Pages: 1546–1558
• DOI: https://doi.org/10.1093/mnras/stz431
• Keywords: galaxies: kinematics and dynamics; galaxies: elliptical and lenticular; galaxies: evolution
• Public URL: https://nottingham-repository.worktribe.com/output/1544960
• Publisher URL: https://academic.oup.com/mnras/article/485/2/1546/5318637
• Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2019 The authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.