The causes of the red sequence, the blue cloud, the green valley, and the green mountain
The galaxies found in optical surveys fall in two distinct regions of a diagram of optical colour versus absolute magnitude: the red sequence and the blue cloud, with the green valley in between. We show that the galaxies found in a submillimetre survey have almost the opposite distribution in this...
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Oxford University Press
2018
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| Subjects: | |
| Online Access: | https://eprints.nottingham.ac.uk/55528/ |
| _version_ | 1848799177827418112 |
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| author | Eales, S.A. Baes, M. Bourne, N. Bremer, Malcolm Brown, M.J.I. Clarke, Christopher de Vis, Pieter Driver, Simon Dunne, Loretta Dye, S. Furlanetto, Cristina Holwerda, Benne W. Ivison, Rob Kelvin, Lee S. Lara-Lopez, Maritza A. Leeuw, L. Loveday, Jon Maddox, Steve Michalowski, Michal Phillipps, Steven Robotham, Aaron Smith, Dan Smith, Matthew Valiante, Elisabetta van der Werf, Paul Wright, Angus |
| author_facet | Eales, S.A. Baes, M. Bourne, N. Bremer, Malcolm Brown, M.J.I. Clarke, Christopher de Vis, Pieter Driver, Simon Dunne, Loretta Dye, S. Furlanetto, Cristina Holwerda, Benne W. Ivison, Rob Kelvin, Lee S. Lara-Lopez, Maritza A. Leeuw, L. Loveday, Jon Maddox, Steve Michalowski, Michal Phillipps, Steven Robotham, Aaron Smith, Dan Smith, Matthew Valiante, Elisabetta van der Werf, Paul Wright, Angus |
| author_sort | Eales, S.A. |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | The galaxies found in optical surveys fall in two distinct regions of a diagram of optical colour versus absolute magnitude: the red sequence and the blue cloud, with the green valley in between. We show that the galaxies found in a submillimetre survey have almost the opposite distribution in this diagram, forming a ‘green mountain’. We show that these distinctive distributions follow naturally from a single, continuous, curved Galaxy Sequence in a diagram of specific star formation rate versus stellar mass, without there being the need for a separate star-forming galaxy main sequence and region of passive galaxies. The cause of the red sequence and the blue cloud is the geometric mapping between stellar mass/specific star formation rate and absolute magnitude/colour, which distorts a continuous Galaxy Sequence in the diagram of intrinsic properties into a bimodal distribution in the diagram of observed properties. The cause of the green mountain is Malmquist bias in the submillimetre waveband, with submillimetre surveys tending to select galaxies on the curve of the Galaxy Sequence, which have the highest ratios of submillimetre-to-optical luminosity. This effect, working in
reverse, causes galaxies on the curve of the Galaxy Sequencee to be under-represented in optical samples, deepening the green valley. The green valley is therefore not evidence (1) for there being two distinct populations of galaxies, (2) for galaxies in this region evolving more quickly than galaxies in the blue cloud and the red sequence, and (3) for rapid-quenching processes in
the galaxy population. |
| first_indexed | 2025-11-14T20:31:32Z |
| format | Article |
| id | nottingham-55528 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T20:31:32Z |
| publishDate | 2018 |
| publisher | Oxford University Press |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-555282018-11-12T14:58:48Z https://eprints.nottingham.ac.uk/55528/ The causes of the red sequence, the blue cloud, the green valley, and the green mountain Eales, S.A. Baes, M. Bourne, N. Bremer, Malcolm Brown, M.J.I. Clarke, Christopher de Vis, Pieter Driver, Simon Dunne, Loretta Dye, S. Furlanetto, Cristina Holwerda, Benne W. Ivison, Rob Kelvin, Lee S. Lara-Lopez, Maritza A. Leeuw, L. Loveday, Jon Maddox, Steve Michalowski, Michal Phillipps, Steven Robotham, Aaron Smith, Dan Smith, Matthew Valiante, Elisabetta van der Werf, Paul Wright, Angus The galaxies found in optical surveys fall in two distinct regions of a diagram of optical colour versus absolute magnitude: the red sequence and the blue cloud, with the green valley in between. We show that the galaxies found in a submillimetre survey have almost the opposite distribution in this diagram, forming a ‘green mountain’. We show that these distinctive distributions follow naturally from a single, continuous, curved Galaxy Sequence in a diagram of specific star formation rate versus stellar mass, without there being the need for a separate star-forming galaxy main sequence and region of passive galaxies. The cause of the red sequence and the blue cloud is the geometric mapping between stellar mass/specific star formation rate and absolute magnitude/colour, which distorts a continuous Galaxy Sequence in the diagram of intrinsic properties into a bimodal distribution in the diagram of observed properties. The cause of the green mountain is Malmquist bias in the submillimetre waveband, with submillimetre surveys tending to select galaxies on the curve of the Galaxy Sequence, which have the highest ratios of submillimetre-to-optical luminosity. This effect, working in reverse, causes galaxies on the curve of the Galaxy Sequencee to be under-represented in optical samples, deepening the green valley. The green valley is therefore not evidence (1) for there being two distinct populations of galaxies, (2) for galaxies in this region evolving more quickly than galaxies in the blue cloud and the red sequence, and (3) for rapid-quenching processes in the galaxy population. Oxford University Press 2018-08-23 Article PeerReviewed application/pdf en https://eprints.nottingham.ac.uk/55528/1/eales2018.pdf Eales, S.A., Baes, M., Bourne, N., Bremer, Malcolm, Brown, M.J.I., Clarke, Christopher, de Vis, Pieter, Driver, Simon, Dunne, Loretta, Dye, S., Furlanetto, Cristina, Holwerda, Benne W., Ivison, Rob, Kelvin, Lee S., Lara-Lopez, Maritza A., Leeuw, L., Loveday, Jon, Maddox, Steve, Michalowski, Michal, Phillipps, Steven, Robotham, Aaron, Smith, Dan, Smith, Matthew, Valiante, Elisabetta, van der Werf, Paul and Wright, Angus (2018) The causes of the red sequence, the blue cloud, the green valley, and the green mountain. Monthly Notices of the Royal Astronomical Society, 481 (1). pp. 1183-1194. ISSN 1365-2966 galaxies: evolution galaxies: general https://academic.oup.com/mnras/article/481/1/1183/5078380 doi:10.1093/mnras/sty2220 doi:10.1093/mnras/sty2220 |
| spellingShingle | galaxies: evolution galaxies: general Eales, S.A. Baes, M. Bourne, N. Bremer, Malcolm Brown, M.J.I. Clarke, Christopher de Vis, Pieter Driver, Simon Dunne, Loretta Dye, S. Furlanetto, Cristina Holwerda, Benne W. Ivison, Rob Kelvin, Lee S. Lara-Lopez, Maritza A. Leeuw, L. Loveday, Jon Maddox, Steve Michalowski, Michal Phillipps, Steven Robotham, Aaron Smith, Dan Smith, Matthew Valiante, Elisabetta van der Werf, Paul Wright, Angus The causes of the red sequence, the blue cloud, the green valley, and the green mountain |
| title | The causes of the red sequence, the blue cloud, the green valley, and the green mountain |
| title_full | The causes of the red sequence, the blue cloud, the green valley, and the green mountain |
| title_fullStr | The causes of the red sequence, the blue cloud, the green valley, and the green mountain |
| title_full_unstemmed | The causes of the red sequence, the blue cloud, the green valley, and the green mountain |
| title_short | The causes of the red sequence, the blue cloud, the green valley, and the green mountain |
| title_sort | causes of the red sequence, the blue cloud, the green valley, and the green mountain |
| topic | galaxies: evolution galaxies: general |
| url | https://eprints.nottingham.ac.uk/55528/ https://eprints.nottingham.ac.uk/55528/ https://eprints.nottingham.ac.uk/55528/ |