Evidence for a Massive, Dark Gravitational Lensing Object in Q2345+007
Abstract
We analyze the narrow absorption line spectra of the double quasar Q2345 +007. The observed pattern of Lyα forest absorption lines gives evidence that the quasar is gravitationally lensed, with 4-to-1 odds in favor of lensing. If Q2345+007 is lensed by an object at z = 1.49, as suggested by observations of heavy-element absorption lines, then a low-luminosity lensing mass of ~10^13^ M_sun_ contained within a transverse distance ~40h^-1^_0_kpc is implied. The Lyα cloud diameters at Z~2 would then be 20+/-10h^-1^_0_kpc [q_0_=0.5] or 28.0+/-14h^-1^_0_kpc [q_0_=0]. If the quasar is not lensed, then the Lyα clouds are larger by a factor of 6.5. We suggest several observational tests which might verify the presence of a massive, dark, lensing object and elucidate its properties.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 1991
- DOI:
- 10.1086/186083
- Bibcode:
- 1991ApJ...375L..41D
- Keywords:
-
- Dark Matter;
- Gravitational Lenses;
- Quasars;
- Absorption Spectra;
- Astronomical Spectroscopy;
- Luminosity;
- Lyman Alpha Radiation;
- Astrophysics;
- DARK MATTER;
- GRAVITATIONAL LENSES;
- QUASARS