Abstract
The fraction of galaxies supported by internal rotation compared to galaxies stabilized by internal pressure provides a strong constraint on galaxy formation models. In integral field spectroscopy surveys, this fraction is biased because survey instruments typically only trace the inner parts of the most massive galaxies. We present aperture corrections for the two most widely used stellar kinematic quantities V/σ and λ R (spin parameter proxy). Our demonstration involves integral field data from the SAMI (Sydney-AAO Multi-object Integral-field spectrograph) Galaxy Survey and the ATLAS 3D survey. We find a tight relation for both V/σ and λ R when measured in different apertures that can be used as a linear transformation as a function of radius, i.e. a first-order aperture correction. In degraded seeing, however, the aperture corrections are more significant as the steeper inner profile is more strongly affected by the point spread function than the outskirts. We find that V/σ and λ R radial growth curves are well approximated by second-order polynomials. By only fitting the inner profile (0.5R e ), we successfully recover the profile out to one R e if a constraint between the linear and quadratic parameter in the fit is applied. However, the aperture corrections for V/σ and λ R derived by extrapolating the profiles perform as well as applying a first-order correction. With our aperture-corrected λ R measurements, we find that the fraction of slow rotating galaxies increases with stellar mass. For galaxies with logM*/M ⊙ > 11, the fraction of slow rotators is 35.9 ± 4.3 per cent, but is underestimated if galaxies without coverage beyond one R e are not included in the sample (24.2 ± 5.3 per cent). With measurements out to the largest aperture radius, the slow rotator fraction is similar as compared to using aperture-corrected values (38.3 ± 4.4 per cent). Thus, aperture effects can significantly bias stellar kinematic integral field spectrograph studies, but this bias can now be removed with the method outlined here.
| Original language | English |
|---|---|
| Pages (from-to) | 1272-1285 |
| Number of pages | 14 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 472 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 2017 Jan 1 |
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All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
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The SAMI Galaxy Survey : Revising the fraction of slow rotators in IFS galaxy surveys. / van de Sande, Jesse; Bland-Hawthorn, Joss; Brough, Sarah; Croom, Scott M.; Cortese, Luca; Foster, Caroline; Scott, Nicholas; Bryant, Julia J.; d'Eugenio, Francesco; Tonini, Chiara; Goodwin, Michael; Konstantopoulos, Iraklis S.; Lawrence, Jon S.; Medling, Anne M.; Owers, Matt S.; Richards, Samuel N.; Schaefer, Adam L.; Yi, Sukyoung K.
In: Monthly Notices of the Royal Astronomical Society, Vol. 472, No. 2, 01.01.2017, p. 1272-1285.Research output: Contribution to journal › Article
TY - JOUR
T1 - The SAMI Galaxy Survey
T2 - Revising the fraction of slow rotators in IFS galaxy surveys
AU - van de Sande, Jesse
AU - Bland-Hawthorn, Joss
AU - Brough, Sarah
AU - Croom, Scott M.
AU - Cortese, Luca
AU - Foster, Caroline
AU - Scott, Nicholas
AU - Bryant, Julia J.
AU - d'Eugenio, Francesco
AU - Tonini, Chiara
AU - Goodwin, Michael
AU - Konstantopoulos, Iraklis S.
AU - Lawrence, Jon S.
AU - Medling, Anne M.
AU - Owers, Matt S.
AU - Richards, Samuel N.
AU - Schaefer, Adam L.
AU - Yi, Sukyoung K.
PY - 2017/1/1
Y1 - 2017/1/1
N2 - The fraction of galaxies supported by internal rotation compared to galaxies stabilized by internal pressure provides a strong constraint on galaxy formation models. In integral field spectroscopy surveys, this fraction is biased because survey instruments typically only trace the inner parts of the most massive galaxies. We present aperture corrections for the two most widely used stellar kinematic quantities V/σ and λ R (spin parameter proxy). Our demonstration involves integral field data from the SAMI (Sydney-AAO Multi-object Integral-field spectrograph) Galaxy Survey and the ATLAS 3D survey. We find a tight relation for both V/σ and λ R when measured in different apertures that can be used as a linear transformation as a function of radius, i.e. a first-order aperture correction. In degraded seeing, however, the aperture corrections are more significant as the steeper inner profile is more strongly affected by the point spread function than the outskirts. We find that V/σ and λ R radial growth curves are well approximated by second-order polynomials. By only fitting the inner profile (0.5R e ), we successfully recover the profile out to one R e if a constraint between the linear and quadratic parameter in the fit is applied. However, the aperture corrections for V/σ and λ R derived by extrapolating the profiles perform as well as applying a first-order correction. With our aperture-corrected λ R measurements, we find that the fraction of slow rotating galaxies increases with stellar mass. For galaxies with logM*/M ⊙ > 11, the fraction of slow rotators is 35.9 ± 4.3 per cent, but is underestimated if galaxies without coverage beyond one R e are not included in the sample (24.2 ± 5.3 per cent). With measurements out to the largest aperture radius, the slow rotator fraction is similar as compared to using aperture-corrected values (38.3 ± 4.4 per cent). Thus, aperture effects can significantly bias stellar kinematic integral field spectrograph studies, but this bias can now be removed with the method outlined here.
AB - The fraction of galaxies supported by internal rotation compared to galaxies stabilized by internal pressure provides a strong constraint on galaxy formation models. In integral field spectroscopy surveys, this fraction is biased because survey instruments typically only trace the inner parts of the most massive galaxies. We present aperture corrections for the two most widely used stellar kinematic quantities V/σ and λ R (spin parameter proxy). Our demonstration involves integral field data from the SAMI (Sydney-AAO Multi-object Integral-field spectrograph) Galaxy Survey and the ATLAS 3D survey. We find a tight relation for both V/σ and λ R when measured in different apertures that can be used as a linear transformation as a function of radius, i.e. a first-order aperture correction. In degraded seeing, however, the aperture corrections are more significant as the steeper inner profile is more strongly affected by the point spread function than the outskirts. We find that V/σ and λ R radial growth curves are well approximated by second-order polynomials. By only fitting the inner profile (0.5R e ), we successfully recover the profile out to one R e if a constraint between the linear and quadratic parameter in the fit is applied. However, the aperture corrections for V/σ and λ R derived by extrapolating the profiles perform as well as applying a first-order correction. With our aperture-corrected λ R measurements, we find that the fraction of slow rotating galaxies increases with stellar mass. For galaxies with logM*/M ⊙ > 11, the fraction of slow rotators is 35.9 ± 4.3 per cent, but is underestimated if galaxies without coverage beyond one R e are not included in the sample (24.2 ± 5.3 per cent). With measurements out to the largest aperture radius, the slow rotator fraction is similar as compared to using aperture-corrected values (38.3 ± 4.4 per cent). Thus, aperture effects can significantly bias stellar kinematic integral field spectrograph studies, but this bias can now be removed with the method outlined here.
UR - http://www.scopus.com/inward/record.url?scp=85044018029&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85044018029&partnerID=8YFLogxK
U2 - 10.1093/mnras/stx1751
DO - 10.1093/mnras/stx1751
M3 - Article
AN - SCOPUS:85044018029
VL - 472
SP - 1272
EP - 1285
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 2
ER -