Query : 2011A&A...531A..64F

2011A&A...531A..64F - Astronomy and Astrophysics, volume 531A, 64-64 (2011/7-1)

A tale of two galaxies: light and mass in NGC 891 and NGC 7814.


Abstract (from CDS):

The two edge-on galaxies NGC 891 and NGC 7814 are representative of two extreme morphologies: the former is disk-dominated while the latter is almost entirely bulge-dominated. It has been argued that since the two galaxies, which are optically so different, have similar rotation curves their total mass distributions cannot be related in any way to the light distributions. This would lead to the conclusion that dark matter is the dominating component of the mass. We have derived new rotation curves from recent, high-sensitivity HI observations and have found that the shapes of the rotation curves are significantly different for the two galaxies. They indicate that in NGC 7814 the mass is more concentrated to the centre as compared to NGC 891. This reflects the distribution of light which is more centrally concentrated in NGC 7814 than in NGC 891. Mass and light do seem to be closely related. This is confirmed by the analysis of the rotation curves in mass components: solutions close to the maximum light (bulge+disk) do provide excellent fits. In NGC 891 bulge and disk can explain the rotation curve without any need for dark matter out to ∼15kpc. In NGC 7814 the bulge dominates in the inner parts; further out the rotation curve is well reproduced by a maximum disk but its M/L ratio is excessively high. A substantial dark matter contribution, closely coupled to the luminous component, seems, therefore, necessary.

Abstract Copyright:

Journal keyword(s): galaxies: kinematics and dynamics - galaxies: structure - galaxies: individual: NGC 891 - galaxies: individual: NGC 7814

Simbad objects: 2

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Number of rows : 2
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 NGC 7814 GiG 00 03 14.947 +16 08 42.82   12.0       ~ 279 0
2 NGC 891 H2G 02 22 32.907 +42 20 53.95 11.08 10.81 9.93 7.86   ~ 1620 2

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