Detection of a Cosmic Microwave Background Decrement toward the ital Z = 3.8 Quasar Pair PC 1643+4631A,B
Abstract
In a 15 GHz Ryle Telescope observation of PC 1643+4631A, B, a pair of quasars at redshifts z = 3.79 and 3.83 separated by 198" on the sky, we find a decrement in the cosmic microwave background (CMB) of -380 +/- 64 μJy in a 110" × 175" beam. Assuming this to be a Sunyaev-Zeldovich effect due to an intervening cluster, the minimum magnitude of the central temperature decrement is 560 μK. A serendipitous ROSAT observation shows that there is no X-ray-luminous cluster in the direction of the decrement at z < 1. The implied gas mass is >~2 × 1014 Msolar (assuming a temperature of ~5 keV), indicating a total mass of more than 1015 Msolar. This result demonstrates the existence of a massive system too distant to be detected by its emission, but which can be found via its imprint on the CMB.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1997
- DOI:
- 10.1086/310564
- arXiv:
- arXiv:astro-ph/9611218
- Bibcode:
- 1997ApJ...479L...1J
- Keywords:
-
- COSMOLOGY: COSMIC MICROWAVE BACKGROUND;
- GALAXIES: CLUSTERS: GENERAL;
- GALAXIES: QUASARS: INDIVIDUAL ALPHANUMERIC: PC 1643+4631A;
- B;
- Cosmology: Cosmic Microwave Background;
- Galaxies: Clusters: General;
- quasars: individual (PC 1643+4631A;
- B);
- Astrophysics
- E-Print:
- 8 pages, LaTeX, 2 PostScript figures. To appear in Astrophysical Journal Letters