Influence of Barlens on the Bulge Parameters in the 2D Image Decomposition

Abstract

Recent observations and simulations have shown that a buckled bar in the face-on view can be considered as a combination of a long flat bar and a short round barlens (corresponding to the boxy/peanut bulge in the edge-on view). However, the barlens component can be misidentified as the bulge, potentially leading to inaccurate bulge parameter measurements in two-dimensional (2D) image decomposition. Our goal is to explore the optimal method for modeling the barlens component and to understand its impact on bulge parameter measurements in 2D image decomposition. We first analyze mock images from two different simulations (with/without bulge) to verify our decomposition method. We then apply the method to two nearby barred galaxies, NGC 1533 and NGC 7329, from the Carnegie-Irvine Galaxy Survey (CGS). Using GALFIT, we conduct 2D image decomposition by gradually increasing the complexity of model configurations. We also explore the effects of inclination by projecting the simulated galaxy to various viewing angles and analyzing the variations in bulge and barlens parameters. From the mock images, we find that the bulge-to-total ratio (B/T) could be overestimated by 50$\%$ without considering the barlens component; the Sérsic index and effective radius of the bulge are also affected to varying degrees. The decomposition results of the two CGS galaxies are consistent with our mock image tests. Uncertainties of the structural parameters of the bulge and barlens are larger at higher inclination angels due to the strong projection effect in the central region. Our findings underscore the necessity of accurately modeling the barlens, revealing that its inclusion in 2D image decomposition can lead to a decrease in B/T by $\sim$30-50$\%$, with other bulge parameters, such as the Sérsic index and effective radius, also affected.

20 pages, 16 figures, accepted for publication in Astronomy & Astrophysics, comments are welcomed

References in corpus (21)

• Structural Properties of Pseudo-Bulges, Classical Bulges and Elliptical Galaxies: an SDSS Perspective
• Dynamics of Barred Galaxies
• A Near-Infrared Study of 2MASS Bars in Local Galaxies: An Anchor for High Redshift Studies
• The Structure of Classical Bulges And Pseudobulges: The Link Between Pseudobulges And Sersic Index
• A Classical Morphological Analysis of Galaxies in the Spitzer Survey of Stellar Structure in Galaxies (S4G)
• Imfit: A Fast, Flexible New Program for Astronomical Image Fitting
• Image Decomposition of Barred Galaxies and AGN Hosts
• The Dependence of Bar Frequency on Galaxy Mass, Colour, and Gas Content -- and Angular Resolution -- in the Local Universe
• Composite Bulges: The Coexistence of Classical Bulges and Disky Pseudobulges in S0 and Spiral Galaxies
• The Carnegie-Irvine Galaxy Survey. III. The Three-Component Structure of Nearby Elliptical Galaxies
• Milky Way mass galaxies with X-shaped bulges are not rare in the local Universe
• Three Mechanisms for Bar Thickening
• An Optimal Strategy for Accurate Bulge-to-disk Decomposition of Disk Galaxies
• Barlenses and X-shape features compared: different manifestations of Boxy/Peanut bulges
• The Carnegie-Irvine Galaxy Survey. V. Statistical study of bars and buckled bars
• Revealing the cosmic evolution of boxy/peanut-shaped bulges from HST COSMOS and SDSS
• The Carnegie-Irvine Galaxy Survey. IX. Classification of Bulge Types and Statistical Properties of Pseudo Bulges
• Composite Bulges -- II. Classical Bulges and Nuclear Discs in Barred Galaxies: The Contrasting Cases of NGC 4608 and NGC 4643
• Is the late buckling stage inevitable in the bar life?
• The secular growth of bars revealed by flat (peak + shoulders) density profiles
• Galaxies decomposition with spiral arms -- II: A multiwavelength case study of M 51