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A combined photometric and kinematic recipe for evaluating the nature of bulges using the CALIFA sample

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A combined photometric and kinematic recipe for evaluating the nature of bulges using the CALIFA sample. / Neumann, J.; CALIFA Collaboration.

In: Astronomy and Astrophysics, Vol. 604, A30, 01.08.2017.

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Neumann, J. ; CALIFA Collaboration. / A combined photometric and kinematic recipe for evaluating the nature of bulges using the CALIFA sample. In: Astronomy and Astrophysics. 2017 ; Vol. 604.

Bibtex

@article{9ee87532d0104b1b9223119d1c2291d6,
title = "A combined photometric and kinematic recipe for evaluating the nature of bulges using the CALIFA sample",
abstract = "Understanding the nature of bulges in disc galaxies can provide important insights into the formation and evolution of galaxies. For instance, the presence of a classical bulge suggests a relatively violent history. In contrast, the presence of an inner disc instead (also referred to as a {"}pseudobulge{"}) indicates the occurrence of secular evolution processes in the main disc. However, we still lack criteria to effectively categorise bulges, limiting our ability to study their impact on the evolution of the host galaxies. Here we present a recipe to separate inner discs from classical bulges by combining four different parameters from photometric and kinematic analyses: the bulge S{\'e}rsic index nb, the concentration index C20,50, the Kormendy (1977, ApJ, 217, 406) relation and the inner slope of the radial velocity dispersion profile ∇σ. With that recipe we provide a detailed bulge classification for a sample of 45 galaxies from the integral-field spectroscopic survey CALIFA. To aid in categorising bulges within these galaxies, we perform 2D image decomposition to determine bulge S{\'e}rsic index, bulge-to-total light ratio, surface brightness and effective radius of the bulge and use growth curve analysis to derive a new concentration index, C20,50. We further extract the stellar kinematics from CALIFA data cubes and analyse the radial velocity dispersion profile. The results of the different approaches are in good agreement and allow a safe classification for approximately 95% of the galaxies. In particular, we show that our new {"}inner{"} concentration index performs considerably better than the traditionally used C50,90 when yielding the nature of bulges. We also found that a combined use of this index and the Kormendy relation gives a very robust indication of the physical nature of the bulge. ",
keywords = "galaxies: bulges, galaxies: photometry, galaxies: kinematics and dynamics, galaxies: structure",
author = "J. Neumann and L. Wisotzki and Choudhury, {O. S.} and Gadotti, {D. A.} and Walcher, {C. J.} and J. Bland-Hawthorn and R. Garc{\'i}a-Benito and {Gonz{\'a}lez Delgado}, {R. M.} and B. Husemann and Marino, {R. A.} and I. M{\'a}rquez and S{\'a}nchez, {S. F.} and B. Ziegler and {CALIFA Collaboration}",
year = "2017",
month = aug,
day = "1",
doi = "10.1051/0004-6361/201730601",
language = "English",
volume = "604",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",

}

RIS

TY - JOUR

T1 - A combined photometric and kinematic recipe for evaluating the nature of bulges using the CALIFA sample

AU - Neumann, J.

AU - Wisotzki, L.

AU - Choudhury, O. S.

AU - Gadotti, D. A.

AU - Walcher, C. J.

AU - Bland-Hawthorn, J.

AU - García-Benito, R.

AU - González Delgado, R. M.

AU - Husemann, B.

AU - Marino, R. A.

AU - Márquez, I.

AU - Sánchez, S. F.

AU - Ziegler, B.

AU - CALIFA Collaboration

PY - 2017/8/1

Y1 - 2017/8/1

N2 - Understanding the nature of bulges in disc galaxies can provide important insights into the formation and evolution of galaxies. For instance, the presence of a classical bulge suggests a relatively violent history. In contrast, the presence of an inner disc instead (also referred to as a "pseudobulge") indicates the occurrence of secular evolution processes in the main disc. However, we still lack criteria to effectively categorise bulges, limiting our ability to study their impact on the evolution of the host galaxies. Here we present a recipe to separate inner discs from classical bulges by combining four different parameters from photometric and kinematic analyses: the bulge Sérsic index nb, the concentration index C20,50, the Kormendy (1977, ApJ, 217, 406) relation and the inner slope of the radial velocity dispersion profile ∇σ. With that recipe we provide a detailed bulge classification for a sample of 45 galaxies from the integral-field spectroscopic survey CALIFA. To aid in categorising bulges within these galaxies, we perform 2D image decomposition to determine bulge Sérsic index, bulge-to-total light ratio, surface brightness and effective radius of the bulge and use growth curve analysis to derive a new concentration index, C20,50. We further extract the stellar kinematics from CALIFA data cubes and analyse the radial velocity dispersion profile. The results of the different approaches are in good agreement and allow a safe classification for approximately 95% of the galaxies. In particular, we show that our new "inner" concentration index performs considerably better than the traditionally used C50,90 when yielding the nature of bulges. We also found that a combined use of this index and the Kormendy relation gives a very robust indication of the physical nature of the bulge.

AB - Understanding the nature of bulges in disc galaxies can provide important insights into the formation and evolution of galaxies. For instance, the presence of a classical bulge suggests a relatively violent history. In contrast, the presence of an inner disc instead (also referred to as a "pseudobulge") indicates the occurrence of secular evolution processes in the main disc. However, we still lack criteria to effectively categorise bulges, limiting our ability to study their impact on the evolution of the host galaxies. Here we present a recipe to separate inner discs from classical bulges by combining four different parameters from photometric and kinematic analyses: the bulge Sérsic index nb, the concentration index C20,50, the Kormendy (1977, ApJ, 217, 406) relation and the inner slope of the radial velocity dispersion profile ∇σ. With that recipe we provide a detailed bulge classification for a sample of 45 galaxies from the integral-field spectroscopic survey CALIFA. To aid in categorising bulges within these galaxies, we perform 2D image decomposition to determine bulge Sérsic index, bulge-to-total light ratio, surface brightness and effective radius of the bulge and use growth curve analysis to derive a new concentration index, C20,50. We further extract the stellar kinematics from CALIFA data cubes and analyse the radial velocity dispersion profile. The results of the different approaches are in good agreement and allow a safe classification for approximately 95% of the galaxies. In particular, we show that our new "inner" concentration index performs considerably better than the traditionally used C50,90 when yielding the nature of bulges. We also found that a combined use of this index and the Kormendy relation gives a very robust indication of the physical nature of the bulge.

KW - galaxies: bulges

KW - galaxies: photometry

KW - galaxies: kinematics and dynamics

KW - galaxies: structure

U2 - 10.1051/0004-6361/201730601

DO - 10.1051/0004-6361/201730601

M3 - Article

VL - 604

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

M1 - A30

ER -

ID: 20946267