The demographics of galactic bulges in the SDSS database
We present a new database of our two-dimensional bulge–disk decompositions for 14,233 galaxies drawn from Sloan Digital Sky Survey DR12 in order to examine the properties of bulges residing in the local universe (0.005 < z < 0.05). We performed decompositions in the g and r bands by utilizing...
| Main Authors: | , , , , , |
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| Format: | Article |
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American Astronomical Society
2016
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| Online Access: | https://eprints.nottingham.ac.uk/39705/ |
| _version_ | 1848795895135469568 |
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| author | Kim, Keunho Oh, Sree Jeong, Hyunjin Aragón-Salamanca, Alfonso Smith, Rory Yi, Sukyoung K. |
| author_facet | Kim, Keunho Oh, Sree Jeong, Hyunjin Aragón-Salamanca, Alfonso Smith, Rory Yi, Sukyoung K. |
| author_sort | Kim, Keunho |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | We present a new database of our two-dimensional bulge–disk decompositions for 14,233 galaxies drawn from Sloan Digital Sky Survey DR12 in order to examine the properties of bulges residing in the local universe (0.005 < z < 0.05). We performed decompositions in the g and r bands by utilizing the galfit software. The bulge colors and bulge-to-total ratios are found to be sensitive to the details in the decomposition technique, and hence we hereby provide full details of our method. The g − r colors of bulges derived are almost constantly red regardless of bulge size, except for the bulges in the low bulge-to-total ratio galaxies (B/T r lesssim 0.3). Bulges exhibit similar scaling relations to those followed by elliptical galaxies, but the bulges in galaxies with lower bulge-to-total ratios clearly show a gradually larger departure in slope from the elliptical galaxy sequence. The scatters around the scaling relations are also larger for the bulges in galaxies with lower bulge-to-total ratios. Both the departure in slopes and larger scatters likely originate from the presence of young stars. The bulges in galaxies with low bulge-to-total ratios show signs of a frosting of young stars so substantial that their luminosity-weighted Balmer-line ages are as small as 1 Gyr in some cases. While bulges seem largely similar in optical properties to elliptical galaxies, they do show clear and systematic departures as a function of bulge-to-total ratio. The stellar properties and perhaps associated formation processes of bulges seem much more diverse than those of elliptical galaxies. |
| first_indexed | 2025-11-14T19:39:21Z |
| format | Article |
| id | nottingham-39705 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:39:21Z |
| publishDate | 2016 |
| publisher | American Astronomical Society |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-397052020-05-04T18:01:42Z https://eprints.nottingham.ac.uk/39705/ The demographics of galactic bulges in the SDSS database Kim, Keunho Oh, Sree Jeong, Hyunjin Aragón-Salamanca, Alfonso Smith, Rory Yi, Sukyoung K. We present a new database of our two-dimensional bulge–disk decompositions for 14,233 galaxies drawn from Sloan Digital Sky Survey DR12 in order to examine the properties of bulges residing in the local universe (0.005 < z < 0.05). We performed decompositions in the g and r bands by utilizing the galfit software. The bulge colors and bulge-to-total ratios are found to be sensitive to the details in the decomposition technique, and hence we hereby provide full details of our method. The g − r colors of bulges derived are almost constantly red regardless of bulge size, except for the bulges in the low bulge-to-total ratio galaxies (B/T r lesssim 0.3). Bulges exhibit similar scaling relations to those followed by elliptical galaxies, but the bulges in galaxies with lower bulge-to-total ratios clearly show a gradually larger departure in slope from the elliptical galaxy sequence. The scatters around the scaling relations are also larger for the bulges in galaxies with lower bulge-to-total ratios. Both the departure in slopes and larger scatters likely originate from the presence of young stars. The bulges in galaxies with low bulge-to-total ratios show signs of a frosting of young stars so substantial that their luminosity-weighted Balmer-line ages are as small as 1 Gyr in some cases. While bulges seem largely similar in optical properties to elliptical galaxies, they do show clear and systematic departures as a function of bulge-to-total ratio. The stellar properties and perhaps associated formation processes of bulges seem much more diverse than those of elliptical galaxies. American Astronomical Society 2016-07-13 Article PeerReviewed Kim, Keunho, Oh, Sree, Jeong, Hyunjin, Aragón-Salamanca, Alfonso, Smith, Rory and Yi, Sukyoung K. (2016) The demographics of galactic bulges in the SDSS database. Astrophysical Journal Supplement Series, 225 (1). 6/1-6/14. ISSN 1538-4365 galaxies: bulges; galaxies: elliptical and lenticular cD; galaxies: formation; galaxies: spiral; galaxies: stellar content; galaxies: structure http://iopscience.iop.org/article/10.3847/0067-0049/225/1/6/meta; doi:10.3847/0067-0049/225/1/6 doi:10.3847/0067-0049/225/1/6 |
| spellingShingle | galaxies: bulges; galaxies: elliptical and lenticular cD; galaxies: formation; galaxies: spiral; galaxies: stellar content; galaxies: structure Kim, Keunho Oh, Sree Jeong, Hyunjin Aragón-Salamanca, Alfonso Smith, Rory Yi, Sukyoung K. The demographics of galactic bulges in the SDSS database |
| title | The demographics of galactic bulges in the SDSS database |
| title_full | The demographics of galactic bulges in the SDSS database |
| title_fullStr | The demographics of galactic bulges in the SDSS database |
| title_full_unstemmed | The demographics of galactic bulges in the SDSS database |
| title_short | The demographics of galactic bulges in the SDSS database |
| title_sort | demographics of galactic bulges in the sdss database |
| topic | galaxies: bulges; galaxies: elliptical and lenticular cD; galaxies: formation; galaxies: spiral; galaxies: stellar content; galaxies: structure |
| url | https://eprints.nottingham.ac.uk/39705/ https://eprints.nottingham.ac.uk/39705/ https://eprints.nottingham.ac.uk/39705/ |