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Title: The stellar halos of massive elliptical galaxies. III. Kinematics at large radius

Abstract

We present a two-dimensional kinematic analysis out to ∼2-5 effective radii (R{sub e} ) of 33 massive elliptical galaxies with stellar velocity dispersions σ > 150 km s{sup –1}. Our observations were taken using the Mitchell Spectrograph (formerly VIRUS-P), a spectrograph with a large 107 × 107 arcsec{sup 2} field of view that allows us to construct robust, spatially resolved kinematic maps of V and σ for each galaxy extending to at least 2 R{sub e} . Using these maps, we study the radial dependence of the stellar angular momentum and other kinematic properties. We see the familiar division between slow and fast rotators persisting out to a large radius in our sample. Centrally slow rotating galaxies, which are almost universally characterized by some form of kinematic decoupling or misalignment, remain slowly rotating in their halos. The majority of fast-rotating galaxies show either increases in specific angular momentum outward or no change beyond R{sub e} . The generally triaxial nature of the slow rotators suggests that they formed through mergers, consistent with a 'two-phase' picture of elliptical galaxy formation. However, we do not observe the sharp transitions in kinematics proposed in the literature as a signpost of moving from centralmore » dissipationally formed components to outer accretion-dominated halos.« less

Authors:
; ;  [1]
  1. Department of Astrophysics, Princeton University, Princeton, NJ 08540 (United States)
Publication Date:
OSTI Identifier:
22357042
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 786; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANGULAR MOMENTUM; DECOUPLING; DISPERSIONS; GALAXIES; MAPS; MECHANICS; STARS; TWO-DIMENSIONAL CALCULATIONS; VELOCITY

Citation Formats

Raskutti, Sudhir, Greene, Jenny E., and Murphy, Jeremy D. The stellar halos of massive elliptical galaxies. III. Kinematics at large radius. United States: N. p., 2014. Web. doi:10.1088/0004-637X/786/1/23.
Raskutti, Sudhir, Greene, Jenny E., & Murphy, Jeremy D. The stellar halos of massive elliptical galaxies. III. Kinematics at large radius. United States. https://doi.org/10.1088/0004-637X/786/1/23
Raskutti, Sudhir, Greene, Jenny E., and Murphy, Jeremy D. 2014. "The stellar halos of massive elliptical galaxies. III. Kinematics at large radius". United States. https://doi.org/10.1088/0004-637X/786/1/23.
@article{osti_22357042,
title = {The stellar halos of massive elliptical galaxies. III. Kinematics at large radius},
author = {Raskutti, Sudhir and Greene, Jenny E. and Murphy, Jeremy D.},
abstractNote = {We present a two-dimensional kinematic analysis out to ∼2-5 effective radii (R{sub e} ) of 33 massive elliptical galaxies with stellar velocity dispersions σ > 150 km s{sup –1}. Our observations were taken using the Mitchell Spectrograph (formerly VIRUS-P), a spectrograph with a large 107 × 107 arcsec{sup 2} field of view that allows us to construct robust, spatially resolved kinematic maps of V and σ for each galaxy extending to at least 2 R{sub e} . Using these maps, we study the radial dependence of the stellar angular momentum and other kinematic properties. We see the familiar division between slow and fast rotators persisting out to a large radius in our sample. Centrally slow rotating galaxies, which are almost universally characterized by some form of kinematic decoupling or misalignment, remain slowly rotating in their halos. The majority of fast-rotating galaxies show either increases in specific angular momentum outward or no change beyond R{sub e} . The generally triaxial nature of the slow rotators suggests that they formed through mergers, consistent with a 'two-phase' picture of elliptical galaxy formation. However, we do not observe the sharp transitions in kinematics proposed in the literature as a signpost of moving from central dissipationally formed components to outer accretion-dominated halos.},
doi = {10.1088/0004-637X/786/1/23},
url = {https://www.osti.gov/biblio/22357042}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 786,
place = {United States},
year = {Thu May 01 00:00:00 EDT 2014},
month = {Thu May 01 00:00:00 EDT 2014}
}