... While there is practically no detector noise present at energies above , X-ray data below are considerably contaminated by noise events, which become more and more dominant towards the lowest transmitted energies (Fig. ... Investigations of 40 hours of in-orbit calibration data with the filter wheel closed, taken over a period of more than two years, showed that the noise properties vary with position and energy, but are fairly stable in time for most areas on the detector. ...

Instrument Summary -- Why Use the GHRS? Here we provide a brief overview of the basic properties of the GHRS. ... The GHRS can obtain spectra from about 1150 to 3200 . ... The repeatability of fluxes is even better, being better than 1%; i.e., it is possible to compare measures of the same wavelength in the same star at different times to within 1% for observations with the LSA. ... The source to be observed may be placed in a Large Science Aperture (LSA) or a Small Science Aperture (SSA). ...

Next: Analysis in the Up: MIDAS utilities for Previous: Fourier analysis . For the detection of smooth signals, e.g. sinusoids, use either SCARGLE/TSA or AOV/TSA with bins. ... SCARGLE/TSA -- . Scargle sine model: This command computes Scargle's (1982) periodogram for unevenly spaced observations x . ... In this way, the command can be used to perform a CLEAN-like analysis manually by removing individual oscillations one by one in the time domain (see Roberts et al. ... AOV/TSA -- . ...

... 314 Astronomical Data Analysis Software and Systems XIII, eds. F. Ochsenbein, M. Allen, & D. Egret (San Francisco: ASP), 812 . ... Abstract: The calculation of flux upper limits in the source-free ("background") regions of photon-limited images is complicated by instrumental and statistical modeling and requires non-trivial computational effort. ... The principal component in this is the time taken to pre-process and handle the 30 GB of RASS data rather than the calculation of each upper limit. ...

... The parameter y   characterizes the ratio between the gravitational and magnetic ``properties'' of a star and will, therefore, be called the gravimagnetic parameter . Two magnetic rotators having quite different magnetic fields, subjected to different external conditions but with identical gravimagnetic parameters, have similar magnetospheres, as long as the accretion rate is quite low ( ). ... For isolated rotators, the accretion rate  yr is assumed. ...

Proposal Identification No.: P2789 Arecibo Observatory Date Received: 2015-Mar-02 16:14:03 William E. Gordon Telescope Observing Time Request COVER SHEET Section I - General Information Submitted for Mar 1 2015. ... For these observations night-time is not needed. Begin ­ End Interval­Interval 18:02 ­ 20:17 17:58 ­ 20:58 ­ ­ 2 Days Needed at This Interval 6 14 Time Constraints (Must Be Justified in the Prop osal Text) The first set of observation sessions require monthly scheduling. ...

... The behaviour of the polarization efficiency (see Eq. ( 14 )) for non-absorbing and absorbing spheroids is shown in Fig. 11 for the case when a maximum polarization is expected (PF alignment, ). ... Figure 11: Polarization efficiency against for prolate and oblate spheroids with and , picket fence orientation, . The size/shape effects are illustrate