The Hydra I cluster offers an excellent opportunity to study and compare the relic old stellar populations in the core of its two brightest galaxies. In addition, the differing kinematics of the two galaxies allows a test of the local validity of general scaling relations. In this work, we present a direct comparison employing full spectral fitting of new high-quality long-slit optical and near-infrared spectroscopic data. We retrieve age, metallicity, and 19 elemental abundances out to similar to 12 kpc within each galaxy, as well as the Initial Mass Function (IMF) in their central regions. Our results suggest that the inner similar to 5 kpc regions of both galaxies, despite their different masses, formed at the same time and evolved with a similar star formation timescale and chemical enrichment, confirming their early formation in the cluster buildup. Only the overall metallicity and IMF radial profiles show differences connected with their different velocity dispersion profiles. The radial trends of the IMF positively correlate with both [Z/H] and sigma. While the trends of the IMF slope values with metallicity agree with a global trend for both galaxies, the trends with the velocity dispersion exhibit differences. The outer regions show signs of mixed stellar populations with large differences in chemical content compared to the centers, but with similarly old ages.
机构:
Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USAUniv Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
Treu, Tommaso
Auger, Matthew W.
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Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USAUniv Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
Auger, Matthew W.
Koopmans, Leon V. E.
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Univ Groningen, Kapteyn Astron Inst, NL-9700 AV Groningen, NetherlandsUniv Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
Koopmans, Leon V. E.
Gavazzi, Raphael
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Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
Univ Paris 06, CNRS, Inst Astrophys Paris, UMR7095, F-75014 Paris, FranceUniv Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
Gavazzi, Raphael
Marshall, Philip J.
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Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USAUniv Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
Marshall, Philip J.
Bolton, Adam S.
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Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA
Univ Utah, Dept Phys & Astron, Salt Lake City, UT 84112 USAUniv Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
机构:
Yale Univ, Astron Dept, New Haven, CT 06511 USAYale Univ, Astron Dept, New Haven, CT 06511 USA
van Dokkum, Pieter
Conroy, Charlie
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h-index: 0
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Harvard Univ, Dept Astron, Cambridge, MA 02138 USAYale Univ, Astron Dept, New Haven, CT 06511 USA
Conroy, Charlie
Villaume, Alexa
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Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USAYale Univ, Astron Dept, New Haven, CT 06511 USA
Villaume, Alexa
Brodie, Jean
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Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USAYale Univ, Astron Dept, New Haven, CT 06511 USA
Brodie, Jean
Romanowsky, Aaron J.
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h-index: 0
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San Jose State Univ, Dept Phys & Astron, San Jose, CA 95192 USA
Univ Calif Observ, 1156 High St, Santa Cruz, CA 95064 USAYale Univ, Astron Dept, New Haven, CT 06511 USA
机构:
Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USAUniv Trieste, Dipartimento Fis, Sez Astron, Via GB Tiepolo 11, I-34100 Trieste, Italy
Cignoni, M.
Tosi, M.
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h-index: 0
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Osservatorio Astron Bologna, INAF, Via Ranzani 1, I-40127 Bologna, ItalyUniv Trieste, Dipartimento Fis, Sez Astron, Via GB Tiepolo 11, I-34100 Trieste, Italy
机构:
Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USAUniv Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
Treu, Tommaso
Auger, Matthew W.
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h-index: 0
机构:
Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USAUniv Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
Auger, Matthew W.
Koopmans, Leon V. E.
论文数: 0引用数: 0
h-index: 0
机构:
Univ Groningen, Kapteyn Astron Inst, NL-9700 AV Groningen, NetherlandsUniv Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
Koopmans, Leon V. E.
Gavazzi, Raphael
论文数: 0引用数: 0
h-index: 0
机构:
Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
Univ Paris 06, CNRS, Inst Astrophys Paris, UMR7095, F-75014 Paris, FranceUniv Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
Gavazzi, Raphael
Marshall, Philip J.
论文数: 0引用数: 0
h-index: 0
机构:
Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USAUniv Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
Marshall, Philip J.
Bolton, Adam S.
论文数: 0引用数: 0
h-index: 0
机构:
Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA
Univ Utah, Dept Phys & Astron, Salt Lake City, UT 84112 USAUniv Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
机构:
Yale Univ, Astron Dept, New Haven, CT 06511 USAYale Univ, Astron Dept, New Haven, CT 06511 USA
van Dokkum, Pieter
Conroy, Charlie
论文数: 0引用数: 0
h-index: 0
机构:
Harvard Univ, Dept Astron, Cambridge, MA 02138 USAYale Univ, Astron Dept, New Haven, CT 06511 USA
Conroy, Charlie
Villaume, Alexa
论文数: 0引用数: 0
h-index: 0
机构:
Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USAYale Univ, Astron Dept, New Haven, CT 06511 USA
Villaume, Alexa
Brodie, Jean
论文数: 0引用数: 0
h-index: 0
机构:
Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USAYale Univ, Astron Dept, New Haven, CT 06511 USA
Brodie, Jean
Romanowsky, Aaron J.
论文数: 0引用数: 0
h-index: 0
机构:
San Jose State Univ, Dept Phys & Astron, San Jose, CA 95192 USA
Univ Calif Observ, 1156 High St, Santa Cruz, CA 95064 USAYale Univ, Astron Dept, New Haven, CT 06511 USA
机构:
Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USAUniv Trieste, Dipartimento Fis, Sez Astron, Via GB Tiepolo 11, I-34100 Trieste, Italy
Cignoni, M.
Tosi, M.
论文数: 0引用数: 0
h-index: 0
机构:
Osservatorio Astron Bologna, INAF, Via Ranzani 1, I-40127 Bologna, ItalyUniv Trieste, Dipartimento Fis, Sez Astron, Via GB Tiepolo 11, I-34100 Trieste, Italy