Overview of the Near-IR S0 Galaxy Survey (NIRS0S)

An overview of the results of the near-IR S0 galaxy survey (NIRS0S) is presented. NIRS0S is a magnitude- (mB⩽12.5 mag) and inclination- (<65∘) limited sample of ̃200 nearby galaxies, mainly S0s, but includes also Sa and E galaxies. It uses deep Ks-band images, typically reaching a surface brightn...

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Main Authors: E. Laurikainen, H. Salo, R. Buta, J. H. Knapen
Format: Article
Language:English
Published: Wiley 2011-01-01
Series:Advances in Astronomy
Online Access:http://dx.doi.org/10.1155/2011/516739
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author E. Laurikainen
H. Salo
R. Buta
J. H. Knapen
author_facet E. Laurikainen
H. Salo
R. Buta
J. H. Knapen
author_sort E. Laurikainen
collection DOAJ
description An overview of the results of the near-IR S0 galaxy survey (NIRS0S) is presented. NIRS0S is a magnitude- (mB⩽12.5 mag) and inclination- (<65∘) limited sample of ̃200 nearby galaxies, mainly S0s, but includes also Sa and E galaxies. It uses deep Ks-band images, typically reaching a surface brightness of 23.5 mag arcsec−2. Detailed visual and photometric classifications were made, for the first time coding also the lenses in a systematic manner. As a comparison sample, a similar sized spiral galaxy sample with similar image quality was used. Based on our analysis, the Hubble sequence was revisited: following the early idea by van den Bergh we suggested that the S0s are spread throughout the Hubble sequence in parallel tuning forks as spirals (S0a, S0b, S0c, etc.). This is evidenced by our improved bulge-to-total (B/T) flux ratios in the S0s, reaching small values typical to late-type spirals. The properties of bulges and disks in S0s were found to be similar to those in spirals and, also, the masses and scale parameters of the bulges and disks to be coupled. It was estimated that the spiral bulges brighter than −20 mag in K-band are massive enough to be converted into the bulges of S0s merely by star formation. Bars were found to be fairly robust both in S0s and spirals, but, inspite of that, bars might evolve significantly within the Hubble sequence.
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spelling doaj-art-43bd02be53be49c99e2920d5519ff1002025-02-03T05:49:41ZengWileyAdvances in Astronomy1687-79691687-79772011-01-01201110.1155/2011/516739516739Overview of the Near-IR S0 Galaxy Survey (NIRS0S)E. Laurikainen0H. Salo1R. Buta2J. H. Knapen3Astronomy Division, Department of Physics, University of Oulu, 90014 Oulu, FinlandAstronomy Division, Department of Physics, University of Oulu, 90014 Oulu, FinlandDepartment of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487, USAInstituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, SpainAn overview of the results of the near-IR S0 galaxy survey (NIRS0S) is presented. NIRS0S is a magnitude- (mB⩽12.5 mag) and inclination- (<65∘) limited sample of ̃200 nearby galaxies, mainly S0s, but includes also Sa and E galaxies. It uses deep Ks-band images, typically reaching a surface brightness of 23.5 mag arcsec−2. Detailed visual and photometric classifications were made, for the first time coding also the lenses in a systematic manner. As a comparison sample, a similar sized spiral galaxy sample with similar image quality was used. Based on our analysis, the Hubble sequence was revisited: following the early idea by van den Bergh we suggested that the S0s are spread throughout the Hubble sequence in parallel tuning forks as spirals (S0a, S0b, S0c, etc.). This is evidenced by our improved bulge-to-total (B/T) flux ratios in the S0s, reaching small values typical to late-type spirals. The properties of bulges and disks in S0s were found to be similar to those in spirals and, also, the masses and scale parameters of the bulges and disks to be coupled. It was estimated that the spiral bulges brighter than −20 mag in K-band are massive enough to be converted into the bulges of S0s merely by star formation. Bars were found to be fairly robust both in S0s and spirals, but, inspite of that, bars might evolve significantly within the Hubble sequence.http://dx.doi.org/10.1155/2011/516739
spellingShingle E. Laurikainen
H. Salo
R. Buta
J. H. Knapen
Overview of the Near-IR S0 Galaxy Survey (NIRS0S)
Advances in Astronomy
title Overview of the Near-IR S0 Galaxy Survey (NIRS0S)
title_full Overview of the Near-IR S0 Galaxy Survey (NIRS0S)
title_fullStr Overview of the Near-IR S0 Galaxy Survey (NIRS0S)
title_full_unstemmed Overview of the Near-IR S0 Galaxy Survey (NIRS0S)
title_short Overview of the Near-IR S0 Galaxy Survey (NIRS0S)
title_sort overview of the near ir s0 galaxy survey nirs0s
url http://dx.doi.org/10.1155/2011/516739
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