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Richard S Ellis - One of the best experts on this subject based on the ideXlab platform.
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Accepted version to appear in ApJ Preprint typeset using LATEX style emulateapj v. 11/10/09 THE RISE AND FALL OF PASSIVE DISK GALAXIES: MORPHOLOGICAL EVOLUTION ALONG THE RED SEQUENCE REVEALED BY COSMOS
2016Co-Authors: Kevin Bundy, Richard S Ellis, Claudia Scarlata, C M Carollo, Niv Drory, Philip Hopkins, Peter Capak, Lucia Pozzetti, Nick ScovilleAbstract:The increasing abundance of passive “red-sequence ” galaxies since z ∼ 1–2 is mirrored by a co-incident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show that in detail the correspondence between galaxy morphology and color is not perfect, providing insight into the physical origin of this evolution. Using the COSMOS survey, we study a signifi-cant population of red-sequence galaxies with disk-like morphologies. These passive disks typically have Sa–Sb morphological types with large bulges, but they are not confined to dense environments. They represent nearly one-half of all red-sequence galaxies and dominate at lower masses (. 1010M) where they are increasingly disk-dominated. As a function of time, the abundance of passive disks with M ∗. 1011M increases, but not as fast as red-sequence Spheroidals in the same mass range. At higher mass, the passive disk population has declined since z ∼ 1, likely because they transform into Spheroidals. Based on these trends, we estimate that as much as 60 % of galaxies transitioning onto the red sequence evolve through a passive disk phase. The origin of passive disks therefore has broad implications for our understanding of how star formation shuts down. Because passive disks tend to be more bulge-dominated than their star-forming counterparts, a simple fading of blue disks does not fully explain their origin. We explore the strengths and weaknesses of several more sophisticated explanations, including environmental effects, internal stabilization, and disk regrowth during gas-rich mergers. While previous work has sought to explain color and morphological transformations with a single process, these observations open the way to new insight by highlighting the fact that galaxy evolution may actually proceed through several separate stages
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the rise and fall of passive disk galaxies morphological evolution along the red sequence revealed by cosmos
The Astrophysical Journal, 2010Co-Authors: Kevin Bundy, Richard S Ellis, Claudia Scarlata, C M Carollo, Niv Drory, Philip F Hopkins, M Salvato, Alexie Leauthaud, A M KoekemoerAbstract:The increasing abundance of passive "red-sequence" galaxies since z ~ 1-2 is mirrored by a coincident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show in detail, that, the correspondence between galaxy morphology and color is not perfect, providing insight into the physical origin of this evolution. Using the COSMOS survey, we study a significant population of red-sequence galaxies with disk-like morphologies. These passive disks typically have Sa-Sb morphological types with large bulges, but they are not confined to dense environments. They represent nearly one-half of all red-sequence galaxies and dominate at lower masses (≾10^(10) M_⊙) where they are increasingly disk-dominated. As a function of time, the abundance of passive disks with M_* ≾10^(11) M_⊙ increases, but not as fast as red-sequence Spheroidals in the same mass range. At higher mass, the passive disk population has declined since z ~ 1, likely because they transform into Spheroidals. Based on these trends, we estimate that as much as 60% of galaxies transitioning onto the red sequence evolve through a passive disk phase. The origin of passive disks therefore has broad implications for our understanding of how star formation shuts down. Because passive disks tend to be more bulge-dominated than their star-forming counterparts, a simple fading of blue disks does not fully explain their origin. We explore the strengths and weaknesses of several more sophisticated explanations, including environmental effects, internal stabilization, and disk regrowth during gas-rich mergers. While previous work has sought to explain color and morphological transformations with a single process, these observations open the way to new insight by highlighting the fact that galaxy evolution may actually proceed through several separate stages.
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THE RISE AND FALL OF PASSIVE DISK GALAXIES: MORPHOLOGICAL EVOLUTION ALONG THE RED SEQUENCE REVEALED BY COSMOS
The Astrophysical Journal, 2010Co-Authors: Kevin Bundy, Richard S Ellis, Claudia Scarlata, C M Carollo, Niv Drory, M Salvato, Alexie Leauthaud, A M Koekemoer, Philip Hopkins, Norman MurrayAbstract:The increasing abundance of passive “red-sequence” galaxies since z similar to 1-2 is mirrored by a coincident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show in detail, that, the correspondence between galaxy morphology and color is not perfect, providing insight into the physical origin of this evolution. Using the COSMOS survey, we study a significant population of red-sequence galaxies with disk-like morphologies. These passive disks typically have Sa-Sb morphological types with large bulges, but they are not confined to dense environments. They represent nearly one-half of all red-sequence galaxies and dominate at lower masses (less than or similar to 10(10) M(circle dot)) where they are increasingly disk-dominated. As a function of time, the abundance of passive disks with M(*) less than or similar to 10(11) M(circle dot) increases, but not as fast as red-sequence Spheroidals in the same mass range. At higher mass, the passive disk population has declined since z similar to 1, likely because they transform into Spheroidals. Based on these trends, we estimate that as much as 60% of galaxies transitioning onto the red sequence evolve through a passive disk phase. The origin of passive disks therefore has broad implications for our understanding of how star formation shuts down. Because passive disks tend to be more bulge-dominated than their star-forming counterparts, a simple fading of blue disks does not fully explain their origin. We explore the strengths and weaknesses of several more sophisticated explanations, including environmental effects, internal stabilization, and disk regrowth during gas-rich mergers. While previous work has sought to explain color and morphological transformations with a single process, these observations open the way to new insight by highlighting the fact that galaxy evolution may actually proceed through several separate stages.
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the rise and fall of passive disk galaxies morphological evolution along the red sequence revealed by cosmos
arXiv: Cosmology and Nongalactic Astrophysics, 2009Co-Authors: Kevin Bundy, Richard S Ellis, Claudia Scarlata, C M Carollo, Niv Drory, Philip F Hopkins, M Salvato, Alexie Leauthaud, A M Koekemoer, Norman MurrayAbstract:The increasing abundance of passive "red-sequence" galaxies since z=1-2 is mirrored by a coincident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show that in detail the correspondence between galaxy morphology and color is not perfect, providing insight into the physical origin of this evolution. Using the COSMOS survey, we study a significant population of red sequence galaxies with disk-like morphologies. These passive disks typically have Sa-Sb morphological types with large bulges, but they are not confined to dense environments. They represent nearly one-half of all red-sequence galaxies and dominate at lower masses (log Mstar < 10) where they are increasingly disk-dominated. As a function of time, the abundance of passive disks with log Mstar < 11 increases, but not as fast as red-sequence Spheroidals in the same mass range. At higher mass, the passive disk population has declined since z~1, likely because they transform into Spheroidals. We estimate that as much as 60% of galaxies transitioning onto the red sequence evolve through a passive disk phase. The origin of passive disks therefore has broad implications for understanding how star formation shuts down. Because passive disks tend to be more bulge-dominated than their star-forming counterparts, a simple fading of blue disks does not fully explain their origin. We explore several more sophisticated explanations, including environmental effects, internal stabilization, and disk regrowth during gas-rich mergers. While previous work has sought to explain color and morphological transformations with a single process, these observations open the way to new insight by highlighting the fact that galaxy evolution may actually proceed through several separate stages.
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evidence for evolving Spheroidals in the hubble deep fields north and south
Monthly Notices of the Royal Astronomical Society, 2001Co-Authors: F Menanteau, Roberto G Abraham, Richard S EllisAbstract:We investigate the dispersion in the internal colours of faint Spheroidals in the Hubble Deep Fields North and South. In high-redshift rapid-collapse scenarios, the dispersion in internal colours should be small at moderate redshift apart from a small metallicity induced reddening in the enriched cores. However, recently assembled Spheroidals are likely to show non-homologous internal colours, at least until younger stellar populations become fully mixed. Here we find that a remarkably large fraction (≳30 per cent) of the morphologically classified Spheroidals with I814W<24 mag show strong variations in internal colour, which we take as evidence for recent episodes of star formation. In most cases these colour variations manifest themselves via the presence of blue cores, an effect of opposite sign to that expected from metallicity gradients. Examining similarly selected ellipticals in five rich clusters with 0.37
Zhensen Wu - One of the best experts on this subject based on the ideXlab platform.
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Scattering of a spheroidal particle illuminated by a Gaussian beam
Applied Optics, 2001Co-Authors: Zhensen WuAbstract:An approach to expanding a Gaussian beam in terms of the spheroidal wave functions in spheroidal coordinates is presented. The beam-shape coefficients of the Gaussian beam in spheroidal coordinates can be computed conveniently by use of the known expression for beam-shape coefficients, gn, in spherical coordinates. The unknown expansion coefficients of scattered and internal electromagnetic fields are determined by a system of equations derived from the boundary conditions for continuity of the tangential components of the electric and magnetic vectors across the surface of the spheroid. A solution to the problem of scattering of a Gaussian beam by a homogeneous prolate (or oblate) spheroidal particle is obtained. The numerical values of the expansion coefficients and the scattered intensity distribution for incidence of an on-axis Gaussian beam are given.
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The expansion coefficients of a spheroidal particle illuminated by Gaussian beam
IEEE Transactions on Antennas and Propagation, 2001Co-Authors: Zhensen WuAbstract:We study the expansion of the Gaussian beam in terms of the prolate spheroidal vector wavefunction. The expansion coefficients are determined. The numerical values of the spheroidal eigenvalues and expansion coefficients have been computed.
Kevin Bundy - One of the best experts on this subject based on the ideXlab platform.
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Accepted version to appear in ApJ Preprint typeset using LATEX style emulateapj v. 11/10/09 THE RISE AND FALL OF PASSIVE DISK GALAXIES: MORPHOLOGICAL EVOLUTION ALONG THE RED SEQUENCE REVEALED BY COSMOS
2016Co-Authors: Kevin Bundy, Richard S Ellis, Claudia Scarlata, C M Carollo, Niv Drory, Philip Hopkins, Peter Capak, Lucia Pozzetti, Nick ScovilleAbstract:The increasing abundance of passive “red-sequence ” galaxies since z ∼ 1–2 is mirrored by a co-incident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show that in detail the correspondence between galaxy morphology and color is not perfect, providing insight into the physical origin of this evolution. Using the COSMOS survey, we study a signifi-cant population of red-sequence galaxies with disk-like morphologies. These passive disks typically have Sa–Sb morphological types with large bulges, but they are not confined to dense environments. They represent nearly one-half of all red-sequence galaxies and dominate at lower masses (. 1010M) where they are increasingly disk-dominated. As a function of time, the abundance of passive disks with M ∗. 1011M increases, but not as fast as red-sequence Spheroidals in the same mass range. At higher mass, the passive disk population has declined since z ∼ 1, likely because they transform into Spheroidals. Based on these trends, we estimate that as much as 60 % of galaxies transitioning onto the red sequence evolve through a passive disk phase. The origin of passive disks therefore has broad implications for our understanding of how star formation shuts down. Because passive disks tend to be more bulge-dominated than their star-forming counterparts, a simple fading of blue disks does not fully explain their origin. We explore the strengths and weaknesses of several more sophisticated explanations, including environmental effects, internal stabilization, and disk regrowth during gas-rich mergers. While previous work has sought to explain color and morphological transformations with a single process, these observations open the way to new insight by highlighting the fact that galaxy evolution may actually proceed through several separate stages
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the rise and fall of passive disk galaxies morphological evolution along the red sequence revealed by cosmos
The Astrophysical Journal, 2010Co-Authors: Kevin Bundy, Richard S Ellis, Claudia Scarlata, C M Carollo, Niv Drory, Philip F Hopkins, M Salvato, Alexie Leauthaud, A M KoekemoerAbstract:The increasing abundance of passive "red-sequence" galaxies since z ~ 1-2 is mirrored by a coincident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show in detail, that, the correspondence between galaxy morphology and color is not perfect, providing insight into the physical origin of this evolution. Using the COSMOS survey, we study a significant population of red-sequence galaxies with disk-like morphologies. These passive disks typically have Sa-Sb morphological types with large bulges, but they are not confined to dense environments. They represent nearly one-half of all red-sequence galaxies and dominate at lower masses (≾10^(10) M_⊙) where they are increasingly disk-dominated. As a function of time, the abundance of passive disks with M_* ≾10^(11) M_⊙ increases, but not as fast as red-sequence Spheroidals in the same mass range. At higher mass, the passive disk population has declined since z ~ 1, likely because they transform into Spheroidals. Based on these trends, we estimate that as much as 60% of galaxies transitioning onto the red sequence evolve through a passive disk phase. The origin of passive disks therefore has broad implications for our understanding of how star formation shuts down. Because passive disks tend to be more bulge-dominated than their star-forming counterparts, a simple fading of blue disks does not fully explain their origin. We explore the strengths and weaknesses of several more sophisticated explanations, including environmental effects, internal stabilization, and disk regrowth during gas-rich mergers. While previous work has sought to explain color and morphological transformations with a single process, these observations open the way to new insight by highlighting the fact that galaxy evolution may actually proceed through several separate stages.
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THE RISE AND FALL OF PASSIVE DISK GALAXIES: MORPHOLOGICAL EVOLUTION ALONG THE RED SEQUENCE REVEALED BY COSMOS
The Astrophysical Journal, 2010Co-Authors: Kevin Bundy, Richard S Ellis, Claudia Scarlata, C M Carollo, Niv Drory, M Salvato, Alexie Leauthaud, A M Koekemoer, Philip Hopkins, Norman MurrayAbstract:The increasing abundance of passive “red-sequence” galaxies since z similar to 1-2 is mirrored by a coincident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show in detail, that, the correspondence between galaxy morphology and color is not perfect, providing insight into the physical origin of this evolution. Using the COSMOS survey, we study a significant population of red-sequence galaxies with disk-like morphologies. These passive disks typically have Sa-Sb morphological types with large bulges, but they are not confined to dense environments. They represent nearly one-half of all red-sequence galaxies and dominate at lower masses (less than or similar to 10(10) M(circle dot)) where they are increasingly disk-dominated. As a function of time, the abundance of passive disks with M(*) less than or similar to 10(11) M(circle dot) increases, but not as fast as red-sequence Spheroidals in the same mass range. At higher mass, the passive disk population has declined since z similar to 1, likely because they transform into Spheroidals. Based on these trends, we estimate that as much as 60% of galaxies transitioning onto the red sequence evolve through a passive disk phase. The origin of passive disks therefore has broad implications for our understanding of how star formation shuts down. Because passive disks tend to be more bulge-dominated than their star-forming counterparts, a simple fading of blue disks does not fully explain their origin. We explore the strengths and weaknesses of several more sophisticated explanations, including environmental effects, internal stabilization, and disk regrowth during gas-rich mergers. While previous work has sought to explain color and morphological transformations with a single process, these observations open the way to new insight by highlighting the fact that galaxy evolution may actually proceed through several separate stages.
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the rise and fall of passive disk galaxies morphological evolution along the red sequence revealed by cosmos
arXiv: Cosmology and Nongalactic Astrophysics, 2009Co-Authors: Kevin Bundy, Richard S Ellis, Claudia Scarlata, C M Carollo, Niv Drory, Philip F Hopkins, M Salvato, Alexie Leauthaud, A M Koekemoer, Norman MurrayAbstract:The increasing abundance of passive "red-sequence" galaxies since z=1-2 is mirrored by a coincident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show that in detail the correspondence between galaxy morphology and color is not perfect, providing insight into the physical origin of this evolution. Using the COSMOS survey, we study a significant population of red sequence galaxies with disk-like morphologies. These passive disks typically have Sa-Sb morphological types with large bulges, but they are not confined to dense environments. They represent nearly one-half of all red-sequence galaxies and dominate at lower masses (log Mstar < 10) where they are increasingly disk-dominated. As a function of time, the abundance of passive disks with log Mstar < 11 increases, but not as fast as red-sequence Spheroidals in the same mass range. At higher mass, the passive disk population has declined since z~1, likely because they transform into Spheroidals. We estimate that as much as 60% of galaxies transitioning onto the red sequence evolve through a passive disk phase. The origin of passive disks therefore has broad implications for understanding how star formation shuts down. Because passive disks tend to be more bulge-dominated than their star-forming counterparts, a simple fading of blue disks does not fully explain their origin. We explore several more sophisticated explanations, including environmental effects, internal stabilization, and disk regrowth during gas-rich mergers. While previous work has sought to explain color and morphological transformations with a single process, these observations open the way to new insight by highlighting the fact that galaxy evolution may actually proceed through several separate stages.
A M Koekemoer - One of the best experts on this subject based on the ideXlab platform.
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the rise and fall of passive disk galaxies morphological evolution along the red sequence revealed by cosmos
The Astrophysical Journal, 2010Co-Authors: Kevin Bundy, Richard S Ellis, Claudia Scarlata, C M Carollo, Niv Drory, Philip F Hopkins, M Salvato, Alexie Leauthaud, A M KoekemoerAbstract:The increasing abundance of passive "red-sequence" galaxies since z ~ 1-2 is mirrored by a coincident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show in detail, that, the correspondence between galaxy morphology and color is not perfect, providing insight into the physical origin of this evolution. Using the COSMOS survey, we study a significant population of red-sequence galaxies with disk-like morphologies. These passive disks typically have Sa-Sb morphological types with large bulges, but they are not confined to dense environments. They represent nearly one-half of all red-sequence galaxies and dominate at lower masses (≾10^(10) M_⊙) where they are increasingly disk-dominated. As a function of time, the abundance of passive disks with M_* ≾10^(11) M_⊙ increases, but not as fast as red-sequence Spheroidals in the same mass range. At higher mass, the passive disk population has declined since z ~ 1, likely because they transform into Spheroidals. Based on these trends, we estimate that as much as 60% of galaxies transitioning onto the red sequence evolve through a passive disk phase. The origin of passive disks therefore has broad implications for our understanding of how star formation shuts down. Because passive disks tend to be more bulge-dominated than their star-forming counterparts, a simple fading of blue disks does not fully explain their origin. We explore the strengths and weaknesses of several more sophisticated explanations, including environmental effects, internal stabilization, and disk regrowth during gas-rich mergers. While previous work has sought to explain color and morphological transformations with a single process, these observations open the way to new insight by highlighting the fact that galaxy evolution may actually proceed through several separate stages.
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THE RISE AND FALL OF PASSIVE DISK GALAXIES: MORPHOLOGICAL EVOLUTION ALONG THE RED SEQUENCE REVEALED BY COSMOS
The Astrophysical Journal, 2010Co-Authors: Kevin Bundy, Richard S Ellis, Claudia Scarlata, C M Carollo, Niv Drory, M Salvato, Alexie Leauthaud, A M Koekemoer, Philip Hopkins, Norman MurrayAbstract:The increasing abundance of passive “red-sequence” galaxies since z similar to 1-2 is mirrored by a coincident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show in detail, that, the correspondence between galaxy morphology and color is not perfect, providing insight into the physical origin of this evolution. Using the COSMOS survey, we study a significant population of red-sequence galaxies with disk-like morphologies. These passive disks typically have Sa-Sb morphological types with large bulges, but they are not confined to dense environments. They represent nearly one-half of all red-sequence galaxies and dominate at lower masses (less than or similar to 10(10) M(circle dot)) where they are increasingly disk-dominated. As a function of time, the abundance of passive disks with M(*) less than or similar to 10(11) M(circle dot) increases, but not as fast as red-sequence Spheroidals in the same mass range. At higher mass, the passive disk population has declined since z similar to 1, likely because they transform into Spheroidals. Based on these trends, we estimate that as much as 60% of galaxies transitioning onto the red sequence evolve through a passive disk phase. The origin of passive disks therefore has broad implications for our understanding of how star formation shuts down. Because passive disks tend to be more bulge-dominated than their star-forming counterparts, a simple fading of blue disks does not fully explain their origin. We explore the strengths and weaknesses of several more sophisticated explanations, including environmental effects, internal stabilization, and disk regrowth during gas-rich mergers. While previous work has sought to explain color and morphological transformations with a single process, these observations open the way to new insight by highlighting the fact that galaxy evolution may actually proceed through several separate stages.
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the rise and fall of passive disk galaxies morphological evolution along the red sequence revealed by cosmos
arXiv: Cosmology and Nongalactic Astrophysics, 2009Co-Authors: Kevin Bundy, Richard S Ellis, Claudia Scarlata, C M Carollo, Niv Drory, Philip F Hopkins, M Salvato, Alexie Leauthaud, A M Koekemoer, Norman MurrayAbstract:The increasing abundance of passive "red-sequence" galaxies since z=1-2 is mirrored by a coincident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show that in detail the correspondence between galaxy morphology and color is not perfect, providing insight into the physical origin of this evolution. Using the COSMOS survey, we study a significant population of red sequence galaxies with disk-like morphologies. These passive disks typically have Sa-Sb morphological types with large bulges, but they are not confined to dense environments. They represent nearly one-half of all red-sequence galaxies and dominate at lower masses (log Mstar < 10) where they are increasingly disk-dominated. As a function of time, the abundance of passive disks with log Mstar < 11 increases, but not as fast as red-sequence Spheroidals in the same mass range. At higher mass, the passive disk population has declined since z~1, likely because they transform into Spheroidals. We estimate that as much as 60% of galaxies transitioning onto the red sequence evolve through a passive disk phase. The origin of passive disks therefore has broad implications for understanding how star formation shuts down. Because passive disks tend to be more bulge-dominated than their star-forming counterparts, a simple fading of blue disks does not fully explain their origin. We explore several more sophisticated explanations, including environmental effects, internal stabilization, and disk regrowth during gas-rich mergers. While previous work has sought to explain color and morphological transformations with a single process, these observations open the way to new insight by highlighting the fact that galaxy evolution may actually proceed through several separate stages.
Alexie Leauthaud - One of the best experts on this subject based on the ideXlab platform.
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the rise and fall of passive disk galaxies morphological evolution along the red sequence revealed by cosmos
The Astrophysical Journal, 2010Co-Authors: Kevin Bundy, Richard S Ellis, Claudia Scarlata, C M Carollo, Niv Drory, Philip F Hopkins, M Salvato, Alexie Leauthaud, A M KoekemoerAbstract:The increasing abundance of passive "red-sequence" galaxies since z ~ 1-2 is mirrored by a coincident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show in detail, that, the correspondence between galaxy morphology and color is not perfect, providing insight into the physical origin of this evolution. Using the COSMOS survey, we study a significant population of red-sequence galaxies with disk-like morphologies. These passive disks typically have Sa-Sb morphological types with large bulges, but they are not confined to dense environments. They represent nearly one-half of all red-sequence galaxies and dominate at lower masses (≾10^(10) M_⊙) where they are increasingly disk-dominated. As a function of time, the abundance of passive disks with M_* ≾10^(11) M_⊙ increases, but not as fast as red-sequence Spheroidals in the same mass range. At higher mass, the passive disk population has declined since z ~ 1, likely because they transform into Spheroidals. Based on these trends, we estimate that as much as 60% of galaxies transitioning onto the red sequence evolve through a passive disk phase. The origin of passive disks therefore has broad implications for our understanding of how star formation shuts down. Because passive disks tend to be more bulge-dominated than their star-forming counterparts, a simple fading of blue disks does not fully explain their origin. We explore the strengths and weaknesses of several more sophisticated explanations, including environmental effects, internal stabilization, and disk regrowth during gas-rich mergers. While previous work has sought to explain color and morphological transformations with a single process, these observations open the way to new insight by highlighting the fact that galaxy evolution may actually proceed through several separate stages.
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THE RISE AND FALL OF PASSIVE DISK GALAXIES: MORPHOLOGICAL EVOLUTION ALONG THE RED SEQUENCE REVEALED BY COSMOS
The Astrophysical Journal, 2010Co-Authors: Kevin Bundy, Richard S Ellis, Claudia Scarlata, C M Carollo, Niv Drory, M Salvato, Alexie Leauthaud, A M Koekemoer, Philip Hopkins, Norman MurrayAbstract:The increasing abundance of passive “red-sequence” galaxies since z similar to 1-2 is mirrored by a coincident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show in detail, that, the correspondence between galaxy morphology and color is not perfect, providing insight into the physical origin of this evolution. Using the COSMOS survey, we study a significant population of red-sequence galaxies with disk-like morphologies. These passive disks typically have Sa-Sb morphological types with large bulges, but they are not confined to dense environments. They represent nearly one-half of all red-sequence galaxies and dominate at lower masses (less than or similar to 10(10) M(circle dot)) where they are increasingly disk-dominated. As a function of time, the abundance of passive disks with M(*) less than or similar to 10(11) M(circle dot) increases, but not as fast as red-sequence Spheroidals in the same mass range. At higher mass, the passive disk population has declined since z similar to 1, likely because they transform into Spheroidals. Based on these trends, we estimate that as much as 60% of galaxies transitioning onto the red sequence evolve through a passive disk phase. The origin of passive disks therefore has broad implications for our understanding of how star formation shuts down. Because passive disks tend to be more bulge-dominated than their star-forming counterparts, a simple fading of blue disks does not fully explain their origin. We explore the strengths and weaknesses of several more sophisticated explanations, including environmental effects, internal stabilization, and disk regrowth during gas-rich mergers. While previous work has sought to explain color and morphological transformations with a single process, these observations open the way to new insight by highlighting the fact that galaxy evolution may actually proceed through several separate stages.
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the rise and fall of passive disk galaxies morphological evolution along the red sequence revealed by cosmos
arXiv: Cosmology and Nongalactic Astrophysics, 2009Co-Authors: Kevin Bundy, Richard S Ellis, Claudia Scarlata, C M Carollo, Niv Drory, Philip F Hopkins, M Salvato, Alexie Leauthaud, A M Koekemoer, Norman MurrayAbstract:The increasing abundance of passive "red-sequence" galaxies since z=1-2 is mirrored by a coincident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show that in detail the correspondence between galaxy morphology and color is not perfect, providing insight into the physical origin of this evolution. Using the COSMOS survey, we study a significant population of red sequence galaxies with disk-like morphologies. These passive disks typically have Sa-Sb morphological types with large bulges, but they are not confined to dense environments. They represent nearly one-half of all red-sequence galaxies and dominate at lower masses (log Mstar < 10) where they are increasingly disk-dominated. As a function of time, the abundance of passive disks with log Mstar < 11 increases, but not as fast as red-sequence Spheroidals in the same mass range. At higher mass, the passive disk population has declined since z~1, likely because they transform into Spheroidals. We estimate that as much as 60% of galaxies transitioning onto the red sequence evolve through a passive disk phase. The origin of passive disks therefore has broad implications for understanding how star formation shuts down. Because passive disks tend to be more bulge-dominated than their star-forming counterparts, a simple fading of blue disks does not fully explain their origin. We explore several more sophisticated explanations, including environmental effects, internal stabilization, and disk regrowth during gas-rich mergers. While previous work has sought to explain color and morphological transformations with a single process, these observations open the way to new insight by highlighting the fact that galaxy evolution may actually proceed through several separate stages.