THE STRUCTURE AND DYNAMICS OF MASSIVE EARLY-TYPE GALAXIES: ON HOMOLOGY, ISOTHERMALITY, AND ISOTROPY INSIDE ONE EFFECTIVE RADIUS
Based on 58 SLACS strong-lens early-type galaxies (ETGs) with direct total-mass and stellar-velocity dispersion measurements, we find that inside one effective radius massive elliptical galaxies with Meff [> over ~] 3 × 10[superscript 10] M[superscript ☉] are well approximated by a power-law elli...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | en_US |
| Published: |
IOP Publishing
2015
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| Online Access: | http://hdl.handle.net/1721.1/96030 |
| _version_ | 1826209203648200704 |
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| author | Koopmans, L. V. E. Bolton, Adam S. Treu, T. Czoske, O. Auger, M. W. Barnabe, M. Vegetti, S. Gavazzi, R. Moustakas, L. A. Burles, Scott |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Koopmans, L. V. E. Bolton, Adam S. Treu, T. Czoske, O. Auger, M. W. Barnabe, M. Vegetti, S. Gavazzi, R. Moustakas, L. A. Burles, Scott |
| author_sort | Koopmans, L. V. E. |
| collection | MIT |
| description | Based on 58 SLACS strong-lens early-type galaxies (ETGs) with direct total-mass and stellar-velocity dispersion measurements, we find that inside one effective radius massive elliptical galaxies with Meff [> over ~] 3 × 10[superscript 10] M[superscript ☉] are well approximated by a power-law ellipsoid, with an average logarithmic density slope of 〈γ'LD〉 ≡ −dlog(ρ[subscript tot]) [over dlog(r)] = 2.085[superscript +0.025 subscript −0.018] (random error on mean) for isotropic orbits with β[subscript r] = 0, ±0.1 (syst.) and σ[subscript γ'] [< over ~] 0.20 [superscript +0.04 subscript -0.02] intrinsic scatter (all errors indicate the 68% CL). We find no correlation of γ'[subscript LD] with galaxy mass (M[subscript eff]), rescaled radius (i.e., R[subscript einst] [over R[subscript eff]]) or redshift, despite intrinsic differences in density-slope between galaxies. Based on scaling relations, the average logarithmic density slope can be derived in an alternative manner, fully independent from dynamics, yielding 〈γ'[subscript SR]〉 = 1.959 ± 0.077. Agreement between the two values is reached for 〈β[subscript r]〉 = 0.45 ± 0.25, consistent with mild radial anisotropy. This agreement supports the robustness of our results, despite the increase in mass-to-light ratio with total galaxy mass: M[subscript eff] ∝ L[superscript 1.363±0.056 subscript V,eff]. We conclude that massive ETGs are structurally close to homologous with close to isothermal total density profiles ([< over ~]10% intrinsic scatter) and have at most some mild radial anisotropy. Our results provide new observational limits on galaxy formation and evolution scenarios, covering 4 Gyr look-back time. |
| first_indexed | 2024-09-23T14:18:49Z |
| format | Article |
| id | mit-1721.1/96030 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T14:18:49Z |
| publishDate | 2015 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/960302022-10-01T20:32:43Z THE STRUCTURE AND DYNAMICS OF MASSIVE EARLY-TYPE GALAXIES: ON HOMOLOGY, ISOTHERMALITY, AND ISOTROPY INSIDE ONE EFFECTIVE RADIUS Koopmans, L. V. E. Bolton, Adam S. Treu, T. Czoske, O. Auger, M. W. Barnabe, M. Vegetti, S. Gavazzi, R. Moustakas, L. A. Burles, Scott Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research Burles, Scott Based on 58 SLACS strong-lens early-type galaxies (ETGs) with direct total-mass and stellar-velocity dispersion measurements, we find that inside one effective radius massive elliptical galaxies with Meff [> over ~] 3 × 10[superscript 10] M[superscript ☉] are well approximated by a power-law ellipsoid, with an average logarithmic density slope of 〈γ'LD〉 ≡ −dlog(ρ[subscript tot]) [over dlog(r)] = 2.085[superscript +0.025 subscript −0.018] (random error on mean) for isotropic orbits with β[subscript r] = 0, ±0.1 (syst.) and σ[subscript γ'] [< over ~] 0.20 [superscript +0.04 subscript -0.02] intrinsic scatter (all errors indicate the 68% CL). We find no correlation of γ'[subscript LD] with galaxy mass (M[subscript eff]), rescaled radius (i.e., R[subscript einst] [over R[subscript eff]]) or redshift, despite intrinsic differences in density-slope between galaxies. Based on scaling relations, the average logarithmic density slope can be derived in an alternative manner, fully independent from dynamics, yielding 〈γ'[subscript SR]〉 = 1.959 ± 0.077. Agreement between the two values is reached for 〈β[subscript r]〉 = 0.45 ± 0.25, consistent with mild radial anisotropy. This agreement supports the robustness of our results, despite the increase in mass-to-light ratio with total galaxy mass: M[subscript eff] ∝ L[superscript 1.363±0.056 subscript V,eff]. We conclude that massive ETGs are structurally close to homologous with close to isothermal total density profiles ([< over ~]10% intrinsic scatter) and have at most some mild radial anisotropy. Our results provide new observational limits on galaxy formation and evolution scenarios, covering 4 Gyr look-back time. United States. National Aeronautics and Space Administration (Jet Propulsion Laboratory (U.S.)) United States. National Aeronautics and Space Administration (Space Telescope Science Institute (U.S.)) 2015-03-16T14:39:01Z 2015-03-16T14:39:01Z 2009-09 2009-06 Article http://purl.org/eprint/type/JournalArticle 0004-637X 1538-4357 http://hdl.handle.net/1721.1/96030 Koopmans, L. V. E., A. Bolton, T. Treu, O. Czoske, M. W. Auger, M. Barnabè, S. Vegetti, R. Gavazzi, L. A. Moustakas, and S. Burles. “THE STRUCTURE AND DYNAMICS OF MASSIVE EARLY-TYPE GALAXIES: ON HOMOLOGY, ISOTHERMALITY, AND ISOTROPY INSIDE ONE EFFECTIVE RADIUS.” The Astrophysical Journal 703, no. 1 (September 2, 2009): L51–L54. © 2009 The American Astronomical Society en_US http://dx.doi.org/10.1088/0004-637x/703/1/l51 Astrophysical Journal Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf IOP Publishing American Astronomical Society |
| spellingShingle | Koopmans, L. V. E. Bolton, Adam S. Treu, T. Czoske, O. Auger, M. W. Barnabe, M. Vegetti, S. Gavazzi, R. Moustakas, L. A. Burles, Scott THE STRUCTURE AND DYNAMICS OF MASSIVE EARLY-TYPE GALAXIES: ON HOMOLOGY, ISOTHERMALITY, AND ISOTROPY INSIDE ONE EFFECTIVE RADIUS |
| title | THE STRUCTURE AND DYNAMICS OF MASSIVE EARLY-TYPE GALAXIES: ON HOMOLOGY, ISOTHERMALITY, AND ISOTROPY INSIDE ONE EFFECTIVE RADIUS |
| title_full | THE STRUCTURE AND DYNAMICS OF MASSIVE EARLY-TYPE GALAXIES: ON HOMOLOGY, ISOTHERMALITY, AND ISOTROPY INSIDE ONE EFFECTIVE RADIUS |
| title_fullStr | THE STRUCTURE AND DYNAMICS OF MASSIVE EARLY-TYPE GALAXIES: ON HOMOLOGY, ISOTHERMALITY, AND ISOTROPY INSIDE ONE EFFECTIVE RADIUS |
| title_full_unstemmed | THE STRUCTURE AND DYNAMICS OF MASSIVE EARLY-TYPE GALAXIES: ON HOMOLOGY, ISOTHERMALITY, AND ISOTROPY INSIDE ONE EFFECTIVE RADIUS |
| title_short | THE STRUCTURE AND DYNAMICS OF MASSIVE EARLY-TYPE GALAXIES: ON HOMOLOGY, ISOTHERMALITY, AND ISOTROPY INSIDE ONE EFFECTIVE RADIUS |
| title_sort | structure and dynamics of massive early type galaxies on homology isothermality and isotropy inside one effective radius |
| url | http://hdl.handle.net/1721.1/96030 |
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