Colors of barlenses: evidence for connecting them to boxy/peanut bulges

Abstract

We study the colors and orientations of structures in low and intermediate inclination barred galaxies. We test the hypothesis that barlenses, roundish central components embedded in bars, could form a part of the bar in a similar manner to boxy/peanut bulges in the edge-on view. A sample of 79 barlens galaxies was selected from the S${}^4$G and the NIRS0S surveys. The sizes, ellipticities, and orientations of barlenses were measured and used to define the barlens regions in the color measurements. The orientations of barlenses were studied with respect to those of the "thin bars" and the line-of-nodes of the disks. For 47 galaxies color maps were constructed using the SDSS images in five optical bands, u, g, r, i, and z. Colors of bars, barlenses, disks, and central regions of the galaxies were measured using two different approaches and color-color diagrams sensitive to metallicity, stellar surface gravity, and short lived stars were constructed. Color differences between the structure components were calculated for each individual galaxy, and presented in histogram form. We find that the colors of barlenses are very similar to those of the surrounding bars, indicating that most probably they form part of the bar. We also find that barlenses have orientations closer to the disk line-of-nodes than to the thin bars, which is consistent with the idea that they are vertically thick, in a similar manner as the boxy/peanut structures in more inclined galaxies. Typically, the colors of barlenses are similar to those of normal E/S0 galaxies. Galaxy by galaxy studies show that in spiral galaxies very dusty barlenses also exist, along with barlenses with rejuvenated stellar populations. The central regions of galaxies are found to be on average redder than bars or barlenses, although galaxies with bluer central peaks also exist.

24 pages, 10 figures, 3 appendices. Accepted for publication in A&A

References in corpus (10)

• HyperLEDA. III. The catalogue of extragalactic distances
• The structure of galactic disks: Studying late-type spiral galaxies using SDSS
• A Classical Morphological Analysis of Galaxies in the Spitzer Survey of Stellar Structure in Galaxies (S4G)
• K-Band Observations of Boxy Bulges. I. Morphology and Surface Brightness Profiles
• Composite Bulges: The Coexistence of Classical Bulges and Disky Pseudobulges in S0 and Spiral Galaxies
• Milky Way mass galaxies with X-shaped bulges are not rare in the local Universe
• Unravelling the mystery of the M31 bar
• Secular- and merger-built bulges in barred galaxies
• Confirmation of a Kinematic Diagnostic for Face-On B/P Bulges
• Optical imaging for the Spitzer Survey of Stellar Structure in Galaxies. Data release and notes on interacting galaxies

Cited by in corpus (6)

• SDSS IV MaNGA: Visual Morphological and Statistical Characterization of the DR15 sample
• Galactic Rings Revisited. I. CVRHS Classifications of 3962 Ringed Galaxies from the Galaxy Zoo 2 Database
• Composite Bulges -- II. Classical Bulges and Nuclear Discs in Barred Galaxies: The Contrasting Cases of NGC 4608 and NGC 4643
• Building the peanut: simulations and observations of peanut-shaped structures and ansae in face-on disk galaxies
• The Profiles of Bars in Spiral Galaxies
• Tilted outer and inner structures in edge-on galaxies?