The 4MOST facility simulator: instrument and science optimisation

This paper describes the design and implementation of a facility simulator for the 4 metre Multi-Object Spectroscopic Telescope (4MOST) project, a new survey instrument proposed for the ESO VISTA telescope. The 4MOST Facility Simulator (4FS) has several roles, firstly to optimise the design of the instrument, secondly to devise a survey strategy for the wide field design reference surveys that are proposed for 4MOST, and thirdly to verify that 4MOST, as designed, can indeed achieve its primary science goals. We describe the overall structure of the 4FS, together with details of some important 4FS subsystems. We present the initial results from the 4FS which illustrate clearly the value of having a functioning facility simulator very early in the conceptual design phase of this large project.Comment: 7 pages, 7 figures, 1 tabl

XMM-Newton study of the ULIRG NGC 6240

A recently performed XMM-Newton observation of the ULIRG NGC 6240 clearly indicates the presence of an AGN contribution to its X-ray spectrum. In the 5.0 - 7.0 keV energy range there is a clear signature of the fluorescent Fe K lines at 6.4, 6.7 and 6.9 keV, respectively. The line strength of the 6.4 keV line cannot be produced by a thermal component. The 0.3 - 10.0 keV spectral energy distribution is characterized by the following components: (I) two hot thermal components (the starburst), (II) one direct component (heavily absorbed; AGN is hidden), (III) one reflection component (the AGN), (IV) three narrow Fe lines. The model parameters for the broad-band spectral energy distribution are consistent with the results of previously works.Comment: 2 pages incl. 2 figures, to appear in the proceedings of the "New Century of X-ray Astronomy" symposium held in Yokohama, Japan (March 6-8, 2001), eds. H. Kunieda and H. Inoue, ASP pres

ROSAT Results on Narrow-Line Seyfert 1 Galaxies

The excellent soft X-ray sensitivity of the PSPC detector onboard the ROSAT satellite provided the first chance to study precisely the spectral and timing properties of Narrow-Line Seyfert 1 galaxies. ROSAT observations of Narrow-Line Seyfert 1 galaxies have revealed (1) the existence of a giant soft X-ray excess, (2) a striking, clear correlation between the strength of the soft X-ray excess emission and the FWHM of the H-beta line, (3) the general absence of significant soft X-ray absorption by neutral hydrogen above the Galactic column, (4) short doubling time scales down to about 1000 seconds, (5) the existence of persistent giant (above a factor of 10), and rapid (less than 1 day) X-ray variability in extragalactic sources. The soft X-ray results on Narrow-Line Seyfert 1 galaxies indicate that their black hole regions are directly visible, further supporting the Seyfert 1 nature of these objects. The extreme X-ray properties of Narrow-Line Seyfert 1 galaxies make them ideal objects for understanding many of the problems raised generally by the Seyfert phenomenon.Comment: Invited talk presented at the Joint MPE,AIP,ESO workshop on NLS1s, Bad Honnef, Dec. 1999, to appear in New Astronomy Reviews; also available at http://wave.xray.mpe.mpg.de/conferences/nls1-worksho

X-ray variability and spectral scaling: a measure of BLR sizes in AGN

We apply a new method of determination of the size of the broad emission-line region (BLR) in active galactic nuclei. This method relates the radius of the broad-line region of AGN to the soft X-ray luminosity and spectral index. Comparing the BLR distances calculated from our photoionization scaling model to the BLR distances determined by reverberation mapping shows that the scaling law agrees with the $R\sim L^{1/2}$ empirical relation. We investigate a complimentary method of estimating the BLR distance - based on the Keplerian broadening of the emission lines and the central mass estimated from X-ray variability.Comment: 4 page latex file, 2 figs. Complete uuencoded compressed PS file is also available at ftp://saba.fiz.huji.ac.il/~pub/wandel/blrx_ts.uu or at http://shum.cc.huji.ac.il/~amri/papers/blrx_ts(tex,ps) to appear in Proc. of Astronomical Time Serie