Two Pseudobulges In The "Boxy Bulge" Galaxy NGC 5746
MetadataShow full item record
Galaxy formation and growth under the Lambda CDM paradigm is expected to proceed in a hierarchical, bottom-up fashion by which small galaxies grow into large galaxies; this mechanism leaves behind large "classical bulges" kinematically distinct from "pseudobulges" grown by internal, secular processes. We use archival data (Spitzer Space Telescope 3.6 mu m wavelength, Hubble Space Telescope H-band, Two Micron All Sky Survey K-s-band, and Sloan Digital Sky Survey gri-band) to measure composite minor-and major-axis surface brightness profiles of the almost-edge-on spiral galaxy NGC 5746. These light profiles span a large range of radii and surface brightnesses to reveal an inner, high surface brightness stellar component that is distinct from the well-known boxy bulge. It is well fitted by Sersic functions with indices n = 0.99 +/- 0.08 and 1.17 +/- 0.24 along the minor and major axes, respectively. Since n < 2, we conclude that this innermost component is a secularly evolved pseudobulge that is distinct from the boxy pseudobulge. This inner pseudobulge makes up 0.136 +/- 0.019 of the total light of the galaxy. It is therefore considerably less luminous than the boxy structure, which is now understood to be a bar seen nearly end-on. The infrared imagery shows further evidence for secular evolution in the form of a bright inner ring of inner radius 9.1 kpc and width 1.6 kpc. NGC 5746 is therefore a giant, pure-disk SB(r) bc galaxy with no sign of a merger-built bulge. We do not understand how such galaxies form in a Lambda DM universe.
CitationBarentine, John C., and John Kormendy. "Two Pseudobulges in the 'Boxy Bulge' Galaxy NGC 5746." The Astrophysical Journal 754, No. 2 (Aug., 2012): 140.
Showing items related by title, author, creator and subject.
Papovich, Casey; Bassett, Robert; Lotz, Jennifer M.; van der Wel, A.; Tran, K. V.; Finkelstein, Steven L.; Bell, Eric F.; Conselice, Christopher J.; Dekel, Avishai; Dunlop, J. S.; Guo, Y. C.; Faber, S. M.; Farrah, D.; Ferguson, Henry C.; Finkelstein, Keely D.; Haussler, Boris; Kocevski, D. D.; Koekemoer, A. M.; Koo, D. C.; McGrath, E. J.; McLure, R. J.; McIntosh, Daniel H.; Momcheva, I.; Newman, Jeffrey A.; Rudnick, Gregory; Weiner, B.; Willmer, Christopher N. A.; Wuyts, S. (2012-05)We discuss the structural and morphological properties of galaxies in a z = 1.62 proto-cluster using near-IR imaging data from Hubble Space Telescope Wide Field Camera 3 data of the Cosmic Assembly Near-IR Deep Extragalactic ...
Adams, Joshua J.; Gebhardt, Karl; Blanc, Guillermo A.; Fabricius, Maximillian H.; Hill, Gary J.; Murphy, Jeremy D.; van den Bosch, Remco C. E.; van de Ven, Glenn (2012-01)We study the mass distribution in the late-type dwarf galaxy NGC 2976 through stellar kinematics obtained with the Visible Integral Field ReplicableUnit Spectrograph Prototype and anisotropic Jeans models as a test of ...
Weinzirl, Tim; Jogee, Shardha; Khochfar, S.; Burkert, Andreas; Kormendy, John (2009-05)We use the bulge Sersic index n and bulge-to-total mass ratio (B/T) to explore the fundamental question of how bulges form. We perform two-dimensional bulge-disk-bar decomposition on H-band images of 143 bright, high-mass ...