Optical Discovery of Intracluster Matter on the Palomar Observatory Sky Survey: The Star Pile in A545
Abstract
This Letter reports the first probable discovery of intracluster matter on the Palomar Observatory Sky Survey: a low surface density feature located in the second richest cluster in Abell's catalog, A545. Galaxy counts show it is located near the cluster center. The feature is present on both the E and O prints, and is red, elongated, ~ 70h^-1^ kpc in diameter (H_0_ = 100h km s^-1^ Mpc^-1^, q_0_ = 0), and at least two nuclei are located within it. Counts of binary galaxies show it is also located at their centroid; two binary galaxies are located at its periphery. The possibility that the feature is interstellar or circumstellar is considered; this seems unlikely because of its color index and central location in the cluster. The purpose of this Letter is to direct attention to the feature for further examination.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 1988
- DOI:
- 10.1086/185197
- Bibcode:
- 1988ApJ...330L..25S
- Keywords:
-
- Galactic Clusters;
- Galactic Structure;
- Sky Surveys (Astronomy);
- Interstellar Matter;
- Statistical Analysis;
- Astrophysics;
- GALAXIES: CLUSTERING