A dataset provided by the European Space Agency

Name 078474
Title Testing Accretion Disc Theory: X-ray - UVW1 Lag Measurement in NGC 4593


DOI https://doi.org/10.5270/esa-m63x5og
Author Prof Ian McHardy
Description Recent Swift UV-optical lag measurements show that UV-optical variability in NGC5548 comes from reprocessing of X-rays by the accretion disc. However the implied disc size is 3x larger than predicted by standard Shakura-Sunyaev theory. Before speculating about the discrepancy we should measure high S-N lags in AGN with different disc parameters. A very large Swift campaign has been proposed for NGC4593, mass 7x lower than NGC5548, with guaranteed continuous Kepler, daily HST and 3x daily griz monitoring. Swift will measure UV-optical lags easily but struggles to measure the estimated 20ks X-ray-UV lag. This timescale is, however, perfectly suited to XMM, as our recent PN-OM fast mode observations of NGC4395 show. Here we propose a 130ks observation to measure the crucial X-ray-UVW1 lag.
Publication No observations found associated with the current proposal
Instrument EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage 2016-07-14T19:08:29Z/2016-07-16T10:36:49Z
Version 17.56_20190403_1200
Mission Description The European Space Agency's (ESA) X-ray Multi-Mirror Mission (XMM-Newton) was launched by an Ariane 504 on December 10th 1999. XMM-Newton is ESA's second cornerstone of the Horizon 2000 Science Programme. It carries 3 high throughput X-ray telescopes with an unprecedented effective area, and an optical monitor, the first flown on a X-ray observatory. The large collecting area and ability to make long uninterrupted exposures provide highly sensitive observations.
Since Earth's atmosphere blocks out all X-rays, only a telescope in space can detect and study celestial X-ray sources. The XMM-Newton mission is helping scientists to solve a number of cosmic mysteries, ranging from the enigmatic black holes to the origins of the Universe itself. Observing time on XMM-Newton is being made available to the scientific community, applying for observational periods on a competitive basis.
Creator Contact https://www.cosmos.esa.int/web/xmm-newton/xmm-newton-helpdesk
Date Published 2017-08-02T22:00:00Z
Publisher And Registrant European Space Agency
Credit Guidelines European Space Agency, 2017-08-02T22:00:00Z, 078474, 17.56_20190403_1200. https://doi.org/10.5270/esa-m63x5og