2017/08/10 by André Z. Vitorelli, A Z Vitorelli, Eduardo S. Cypriano +8 · 18 citations
Physics and Astronomy · #Apparent magnitude #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Magnitude (astronomy) #Measure (data warehouse) #Physics #Redshift #Stars #Stellar, planetary, and galactic studies #Weak gravitational lensing #astro-ph.CO
paper · pdf · doi:10.1093/mnras/stx2791
published in Monthly Notices of the Royal Astronomical Society 474(1), 866-875 (Oxford University Press) · 10 pages, 5 figures, 5 tables, submitted to the MNRAS
arxiv created 2017/08/10 · openalex created_date 2017/08/31 · openalex publication_date 2017/10/26 · arxiv updated 2017/12/20 · openalex updated_date 2026/08/06
Galaxy systems with large magnitude gaps -defined as the difference in magnitude between the central galaxy and the brightest satellite in the central region, such as fossil groups -are claimed to have earlier formation times. In this study, we measure the mass concentration, as an indicator of the formation epoch, of ensembles of galaxy systems divided by redshift and magnitude gaps in the r band. We use cross-correlation weak-lensing measurements with NFW parametric mass profiles to measure masses and concentrations of these ensembles from a catalogue of systems built from the SDSS Coadd by the redMaPPer algorithm. The lensing shear data come from the CFHT Stripe 82 (CS82) survey, and consists of i-band images of the SDSS Stripe 82 region. We find that the stack made up of systems with larger magnitude gaps has a high probability of being more concentrated, in the lowest redshift slice (0.2 < z < 0.4), both when dividing in quartiles (P = 0.98) and tertiles (P = 0.85). These results lend credibility to the claim that systems with large magnitude gaps tend to have been formed early.