Detalles de publicación
PP 08028
Discovery of a Giant Stellar Tidal Stream Around the Disk Galaxy NGC 4013
(1)IAC (2) Max-Planck Institut für Astronomie, Heidelberg, Germany (3) Ramón y Cajal Fellow (4) Cardiff University, School of Physics & Astronomy, Cardiff, UK (5) Kapteyn Institut, Rijksuniversiteit Groningen, Groningen, The Netherlands (6) BlackBird Observatory, Mayhill, New Mexico USA (7) Department of Astronomy, University of Virginia, Charlottesville, USA (8) Department of Physics & Astronomy, University of Vitoria, Canada (9) Visiting Astronomer, Kitt Peak National Observatory (10) Now at Department of Astronomy, Penn State University, Davey Lab, University Park
We report the discovery of a giant, loop-like stellar structure around the edge-on spiral galaxy NGC 4013. This arcing feature extends 6' (~ 26 kpc in projected distance) northeast from the center and 3' (~12 kpc) from the disk plane; likely related features are also apparent on the southwest side of the disk, extending to 4' (~ 17 kpc). The detection of this low surface-brightness (~ 27.0 mag/arcsec^2) structure is independently confirmed in three separate datasets from three different telescopes.
Although its true three dimensional geometry is unknown, the sky-projected morphology of this structure displays a match with the theoretical predictions for the edge-on, projected view of a stellar tidal stream of a dwarf satellite moving in a low inclinated (~25º), nearly circular orbit. Using the recent model of the Monoceros tidal stream in the Milky Way by Peñarrubia et al. as template, we find that the progenitor system may have been a galaxy with an initial mass 6x10^8 Ms, of which current position and final fate is unknown. According to this simulation, the tidal stream may be approximately ~2.8 Gyr of age.
Our results demostrate that NGC 4013, previously considered a prototypical isolated disk galaxy in spite of having on of the most prominent HI warps detected thus far, may have in fact suffered a recent minor merger. This discovery highlights that undisturbed disks at high surface brightness levels in the optical but warped in HI maps in fact reveal complex signatures of recent accretion events in deep photometric surveys.
Although its true three dimensional geometry is unknown, the sky-projected morphology of this structure displays a match with the theoretical predictions for the edge-on, projected view of a stellar tidal stream of a dwarf satellite moving in a low inclinated (~25º), nearly circular orbit. Using the recent model of the Monoceros tidal stream in the Milky Way by Peñarrubia et al. as template, we find that the progenitor system may have been a galaxy with an initial mass 6x10^8 Ms, of which current position and final fate is unknown. According to this simulation, the tidal stream may be approximately ~2.8 Gyr of age.
Our results demostrate that NGC 4013, previously considered a prototypical isolated disk galaxy in spite of having on of the most prominent HI warps detected thus far, may have in fact suffered a recent minor merger. This discovery highlights that undisturbed disks at high surface brightness levels in the optical but warped in HI maps in fact reveal complex signatures of recent accretion events in deep photometric surveys.