Open AccessNuclear spirals in galaxies: gas response to an asymmetric potential – I. Linear theory
Author(s) -
Maciejewski Witold
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.08253.x
Subject(s) - physics , galaxy , astrophysics , gravitational potential , nuclear astrophysics , spiral galaxy , gravitation , galaxy rotation curve , astronomy , galaxy formation and evolution
Nuclear spirals can provide a wealth of information about the nuclear potential in disc galaxies. They are unlikely to form in nuclei with solid‐body rotation, yet they are present in a majority of galactic centres. Their morphology varies depending on whether a central massive black hole (MBH) is present in or absent from the galaxy. In this paper I consider predictions of the linear theory for waves induced in gas by an asymmetric gravitational potential, which are applicable to the nuclear spirals observed in galaxies. The generation and propagation of waves are governed by dynamical resonances, and inclusion of an MBH can move or even create resonances, greatly altering the extent and shape of the nuclear spiral. I will use predictions of the linear theory presented here as a guideline when interpreting hydrodynamical models in the second paper of this series. I also comment on modifications that self‐gravity in gas imposes on the induced waves.