PROPOSAL OVERVIEW | |
Proposal Title | High-redshift quasars: Cosmology and Physics |
Proposal Category | Active Galactic Nuclei, Quasars, BL-Lac Objects and Tidal Disruption Events |
Proposal Type | LARGE PROGRAM |
Proposal Id | 084497 |
Number of Observations | 19 |
Total exposure time (ks) | 1377 |
PI DETAILS | |
PI | Dr Elisabeta Lusso |
Institute | Durham University |
Country | UNITED KINGDOM |
CO-INVESTIGATORS | ||
Name | Country | |
G. Risaliti | ITALY | |
E. Nardini | ITALY | |
M. Elvis | UNITED STATES | |
C. Vignali | ITALY | |
R. Gilli | ITALY | |
S. Bisogni | ITALY | |
F. Salvestrini | ITALY |
ABSTRACT | |
The non-linear X-ray/UV relation in quasars can be used to build a Hubble diagram and test cosmological models at high redshift. To this aim, we were awarded an XMM LP to observe 30 bright quasars at z~3. We found a tighter-than- expected X-ray/UV relation, implying that pointed observations can greatly reduce the uncertainties in the determination of quasar distances, and a new population of X-ray weak quasars that represents ~30% of the z~3 sample. We propose an extensive survey of bright, radio-quiet, SDSS quasars at z~4 with the goals of (1) detecting a 4sigma deviation from the LambdaCDM model using this z~4 sample alone, (2) measuring the X-ray weak fraction of quasars for the first time at z~4 and its evolution with time. |
PAPERS |
- CLASS 1: | papers that present specific XMM-Newton observations |
- CLASS 2: | papers that refer to published XMM-Newton results with complementary observations, follow-up analysis, or theoretical analysis |
- CLASS 3: | further deliveries which resulted from the program and which are made available to the community (e.g. source catalogues, processed images or spectra in public data base) |
- CLASS 4: | comments and suggestions from PI |