NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-08-23 T05:03:23 PDT
Help | Comment | NED Home

For refcode 1992A&A...253..335K:
Retrieve 1 NED object in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by European Southern Observatory (ESO). Reproduced by permission
1992A&A...253..335K Kinematics of the extended H I disk of NGC 628 High velocity gas and deviations from circular rotation Jurjen Kamphuis and Frank Briggs Kapteyn Astronomical Institute Groningen, NL-9700 AY Groningen, The Netherlands University of Pittsburgh, Pittsburgh, PA 15260, U.S.A. Received July 2, accepted September 9, 1991 Abstract. HI observations of the face-on ScI galaxy NGC 628 with the VLA reveal new details in the kinematics for an isolated, extended HI disk. On a global scale, the analysis of the velocity field shows: (1) clear regression of the line-of-the-nodes in the well-known warp, (2) two symmetrically placed high velocity complexes (HVCs) that do not fit into a warped disk model of inclined, circular rings, and (3) an extended arm or tail of HI that arcs over one third of the circumference of NGC 628 and extends outwards to include the most distant HI associated with the galaxy. The extended arc does not have a symmetrically located counter- part, and it is speculated that either the arc is from primordial origin or it represents a tidally dispersed remnant of an HI-rich object (M_HI_ ~ 9 10^8^ M_sun_) that is merging into the outer disk. The presence of the added mass in the outer disk distorts NGC 628 itself, creating the HVCs as tidal by-products. Superimposed on the large scale symmetries and systematic behavior the galaxy as a whole shows a trend of increasingly chaotic motion toward larger radii. We are probably witnessing a stage in the evolution of a large isolated system as it settles toward a flattened disk after enduring numerous accretion events. The evidence for recent accretion helps to solve the problem of warp longevity since the warp is excited by the acquired mass. Key words: Galaxies: individual: NGC 628 - kinematics and dynamics of - Radio lines: 21-cm
Retrieve 1 NED object in this reference.
Please click here for ADS abstract

Back to NED Home