Galaxy Zoo: star formation versus spiral arm number
Spiral arms are common features in low-redshift disc galaxies, and are prominent sites of star formation and dust obscuration. However, spiral structure can take many forms: from galaxies displaying two strong ‘grand design’ arms to those with many ‘flocculent’ arms. We investigate how these differe...
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| Format: | Article |
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Oxford University Press
2017
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| Online Access: | https://eprints.nottingham.ac.uk/43376/ |
| _version_ | 1848796674226388992 |
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| author | Hart, Ross E. Bamford, Steven P. Casteels, Kevin R.V. Kruk, Sandor J. Lintott, Chris J. Masters, Karen L. |
| author_facet | Hart, Ross E. Bamford, Steven P. Casteels, Kevin R.V. Kruk, Sandor J. Lintott, Chris J. Masters, Karen L. |
| author_sort | Hart, Ross E. |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | Spiral arms are common features in low-redshift disc galaxies, and are prominent sites of star formation and dust obscuration. However, spiral structure can take many forms: from galaxies displaying two strong ‘grand design’ arms to those with many ‘flocculent’ arms. We investigate how these different arm types are related to a galaxy's star formation and gas properties by making use of visual spiral arm number measurements from Galaxy Zoo 2. We combine ultraviolet and mid-infrared (MIR) photometry from GALEX and WISE to measure the rates and relative fractions of obscured and unobscured star formation in a sample of low-redshift SDSS spirals. Total star formation rate has little dependence on spiral arm multiplicity, but two-armed spirals convert their gas to stars more efficiently. We find significant differences in the fraction of obscured star formation: an additional ∼10 per cent of star formation in two-armed galaxies is identified via MIR dust emission, compared to that in many-armed galaxies. The latter are also significantly offset below the IRX–β relation for low-redshift star-forming galaxies. We present several explanations for these differences versus arm number: variations in the spatial distribution, sizes or clearing time-scales of star-forming regions (i.e. molecular clouds), or contrasting recent star formation histories. |
| first_indexed | 2025-11-14T19:51:44Z |
| format | Article |
| id | nottingham-43376 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:51:44Z |
| publishDate | 2017 |
| publisher | Oxford University Press |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-433762020-05-04T18:53:12Z https://eprints.nottingham.ac.uk/43376/ Galaxy Zoo: star formation versus spiral arm number Hart, Ross E. Bamford, Steven P. Casteels, Kevin R.V. Kruk, Sandor J. Lintott, Chris J. Masters, Karen L. Spiral arms are common features in low-redshift disc galaxies, and are prominent sites of star formation and dust obscuration. However, spiral structure can take many forms: from galaxies displaying two strong ‘grand design’ arms to those with many ‘flocculent’ arms. We investigate how these different arm types are related to a galaxy's star formation and gas properties by making use of visual spiral arm number measurements from Galaxy Zoo 2. We combine ultraviolet and mid-infrared (MIR) photometry from GALEX and WISE to measure the rates and relative fractions of obscured and unobscured star formation in a sample of low-redshift SDSS spirals. Total star formation rate has little dependence on spiral arm multiplicity, but two-armed spirals convert their gas to stars more efficiently. We find significant differences in the fraction of obscured star formation: an additional ∼10 per cent of star formation in two-armed galaxies is identified via MIR dust emission, compared to that in many-armed galaxies. The latter are also significantly offset below the IRX–β relation for low-redshift star-forming galaxies. We present several explanations for these differences versus arm number: variations in the spatial distribution, sizes or clearing time-scales of star-forming regions (i.e. molecular clouds), or contrasting recent star formation histories. Oxford University Press 2017-06-30 Article PeerReviewed Hart, Ross E., Bamford, Steven P., Casteels, Kevin R.V., Kruk, Sandor J., Lintott, Chris J. and Masters, Karen L. (2017) Galaxy Zoo: star formation versus spiral arm number. Monthly Notices of the Royal Astronomical Society, 468 (2). pp. 1850-1863. ISSN 1365-2966 Galaxies Galaxies spiral Star formation Structure of galaxies https://doi.org/10.1093/mnras/stx581 doi:10.1093/mnras/stx581 doi:10.1093/mnras/stx581 |
| spellingShingle | Galaxies Galaxies spiral Star formation Structure of galaxies Hart, Ross E. Bamford, Steven P. Casteels, Kevin R.V. Kruk, Sandor J. Lintott, Chris J. Masters, Karen L. Galaxy Zoo: star formation versus spiral arm number |
| title | Galaxy Zoo: star formation versus spiral arm number |
| title_full | Galaxy Zoo: star formation versus spiral arm number |
| title_fullStr | Galaxy Zoo: star formation versus spiral arm number |
| title_full_unstemmed | Galaxy Zoo: star formation versus spiral arm number |
| title_short | Galaxy Zoo: star formation versus spiral arm number |
| title_sort | galaxy zoo: star formation versus spiral arm number |
| topic | Galaxies Galaxies spiral Star formation Structure of galaxies |
| url | https://eprints.nottingham.ac.uk/43376/ https://eprints.nottingham.ac.uk/43376/ https://eprints.nottingham.ac.uk/43376/ |