Query : 2011A&A...529A..51G

2011A&A...529A..51G - Astronomy and Astrophysics, volume 529A, 51-51 (2011/5-1)

The apparent ``reversed'' motion of gas and stars in M 82.


Abstract (from CDS):

We summarize earlier and unpublished long-slit spectroscopic measurements of radial velocities of ionized gas and stars along and parallel to M82's major axis to a radial distance of ~±2.5kpc (~±140'') from the center. In the position-velocity diagram, these measurements indicate a velocity reversal of ∼100km/s of gas and/or stars at ~±1.0kpc (~±50-70'') on either side of the center, outside the bar. Although seen in earlier observations, and perhaps neglected because they were assumed to be only an effect of heavy local extinction, the positional symmetry of the velocity reversal with respect to the center of M82, as well as the absence of the reversal in the motion of stars seen in the near-IR Caii absorption lines, points to another origin. M82's two-armed spiral, as outlined by Mayya et al. (2005ApJ...628L..33M), may explain a part of the velocity reversal, although this interpretation leaves inconsistencies so that other explanations must also be investigated. A simple, conclusive explanation of the velocity reversal has not yet been found. While restricted observationally in radial distance to ∼120'' (2kpc), the near-IR stellar CaII absorption lines, which do not show the velocity reversal, indicate a flat radial velocity curve of the stellar disk that remained after the encounter with M81.

Abstract Copyright:

Journal keyword(s): galaxies: individual: M82 - galaxies: kinematics and dynamics

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
1 M 81 Sy2 09 55 33.1726556496 +69 03 55.062505368   7.89 6.94     ~ 4441 3
2 M 82 AGN 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 5852 6
3 NGC 3077 GiP 10 03 19.0965510921 +68 44 01.556166166 11.23 10.85 10.14 9.74   ~ 770 0
4 NGC 4151 Sy1 12 10 32.5759813872 +39 24 21.063527532   12.18 11.48     ~ 3687 2

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