Star Formation in the Cooling Flows of M87/Virgo and NGC 1275/Perseus
Abstract
X-ray observations indicate that M87/Virgo and NGC 1275/Perseus have cooling flows which are associated with accretion rates of ~20-30 and ~300-500 M_sun_ yr^-1^, respectively. By deconvolving X-ray surface brightness profiles of these cooling flow clusters, a number of authors have found the respective accretion rates to decrease inward, suggesting that the bulk of the mass flux is dropping out (presumably to form stars). However, cooling flow models which assume the mass flux is constant with radius (so there is no star formation) have never been calculated self-consistently for these objects. We therefore assess whether star formation is necessarily occurring in these cooling flows by calculating constant mass-flux models for all reasonable parameter space. We assume that the inflow is steady state, and that collisional heating and thermal conduction are insignificant. We find no constant-mass-flux models which are consistent with all of the relevant observations, so we conclude that mass is indeed dropping out of these cooling flows. We then consider a variety of star-forming models in which the X-ray emission due to cooling condensates is taken into account. For M87/Virgo we can find models in which the mass flux vanishes by the center. In NGC 1275/Perseus, we find that the mass flux diminishes by <~40% by the time the flow reaches ~20 kpc (the effective inner limit of the X-ray surface brightness data). The remaining mass flux within 20 kpc is ~300 M_sun_ yr^-1^, which is unacceptably high for the flow temperatures we derive.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 1988
- DOI:
- 10.1086/166959
- Bibcode:
- 1988ApJ...335..688W
- Keywords:
-
- Accretion Disks;
- Interstellar Matter;
- Star Formation;
- Virgo Galactic Cluster;
- X Ray Sources;
- Galactic Mass;
- Hubble Constant;
- Interstellar Gas;
- Mass Flow;
- Astrophysics;
- GALAXIES: INDIVIDUAL MESSIER NUMBER: M87;
- GALAXIES: INDIVIDUAL NGC NUMBER: NGC 1275;
- GALAXIES: INTERSTELLAR MATTER;
- GALAXIES: X-RAYS;
- STARS: FORMATION