Abstract
We examine the gravitational redshift of radiation emitted from within the potential of a cluster. Spectral lines from the intracluster medium (ICM) are redshifted in proportion to the emission-weighted mean potential along the line of sight, amounting to ≈50 km s-1 at a radius of 100 kpc h-1, for a cluster dispersion of 1200 km s-1. We show that the relative redshifts of different ionization states of metals in the ICM provide a unique probe of the three-dimensional matter distribution. An examination of the reported peculiar velocities of cD galaxies in well-studied Abell clusters reveals that they are typically redshifted by an average of ∼200 km s-1. This can be achieved by gravity with the addition of a steep central potential associated with the cD galaxy. Note that, in general, gravitational redshifts cause a small overestimate of the recessional velocities of clusters by an average of ∼20 km s-1.
Original language | English (US) |
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Pages (from-to) | L93-L97 |
Journal | Astrophysical Journal |
Volume | 533 |
Issue number | 2 PART 2 |
DOIs | |
State | Published - Apr 20 2000 |
Externally published | Yes |
Keywords
- Cosmology: observations
- Galaxies: clusters: general
- Techniques: spectroscopic
- X-rays: galaxies
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science