2014/06/30 by E. Laurikainen, H. Salo, E. Athanassoula +2 · 1 citation
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Milky Way #Physics #astro-ph.GA
paper · pdf · doi:10.1093/mnrasl/slu118
First submission (sent to astro-ph in June 2014) replaced with the version accepted to MNRAS Letters (Vol. 444, L80-84). The biggest difference to the previous submission is Fig. 2
openalex publication_date 2014/08/18 · arxiv created 2014/08/22 · arxiv updated 2014/08/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract Boxy/Peanut/X-shaped (B/P/X) bulges are studied using the 3.6 μm images from the Spitzer Survey of Stellar Structure in Galaxies, and the Ks-band images from the Near-IR S0 galaxy Survey. They are compared with the properties of barlenses, defined as lens-like structures embedded in bars, with sizes of ∼50 per cent of bars and axial ratios of ∼0.6–0.9. Based on observations (extending Laurikainen et al.) and recent simulation models, we show evidence that barlenses are the more face-on counterparts of B/P/X-shaped bulges. Using unsharp masks 18 new X-shaped structures are identified, covering a large range of galaxy inclinations. The similar masses and red B−3.6 μm colours of the host galaxies, and the fact that the combined axial ratio distribution of the host galaxy discs is flat, support the interpretation that barlenses and X-shapes are physically the same phenomenon. In Hubble types −3 ≤ T ≤ 2 even half of the bars contain either a barlens or an X-shaped structure. Our detailed 2D multicomponent decompositions for 29 galaxies, fitting the barlens/X-shape with a separate component, indicate very small or non-existent classical bulges. Taking into account that the structures we study have similar host galaxy masses as the Milky Way (MW), our results imply that MW mass galaxies with no significant classical bulges are common in the nearby Universe.