Astronomy & Astrophysics

All Figures

$\begin{figure} \par\resizebox{8.8cm}{!}{\includegraphics{0220fg01.eps}} % \end{figure}$ Figure 1: Domains in ${\it FPP}$ vs. Sample Size covered by the four formulae. The labels indicate the number of the equation used to calculate the probability. The structures in the dark grey area are due to the different validity criteria for even and odd numbers in Eq. (6)
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In the text

$\begin{figure} \par\resizebox{8.8cm}{!}{\includegraphics{0220fg02.eps}} % \end{figure}$ Figure 2: Sensitivities of Kuiper's and Rayleigh's tests as a function of the S/N between the pulse and the continuum. a) 20 counts in the pulse; b) 100 counts; c) 500 counts. In each graph, the curves are (from top to bottom) w=1, w=3/4, w=1/2, w=1/4. The w=3/4 and w=1/4 curves are highlighted in light grey for visual identification. The solid line is Kuiper's test; the dashed line Rayleigh's.
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In the text

$\begin{figure} \par\resizebox{8.8cm}{!}{\includegraphics{0220fg03.eps}} % \end{figure}$ Figure 3: Ratio $R(k)=n_{{\rm eff}}/n$ as a function of k for five different "observations'': two continuous (20 and 200 photons) ones, and three corresponding to obs. RP300093N00, RP300262N00, and RP700232N00 with 100, 1596, and 377 photons. The grey area shows the uncertainties for one of the five curves. The dashed line has a slope -1.
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In the text

$\begin{figure} \par\resizebox{8.8cm}{!}{\includegraphics{0220fg04.eps}} % \end{figure}$ Figure 4: Effect of the GTIs on Rayleigh's (top) and Kuiper's (bottom) tests. a-b) Simulated 1000 s 1000-photon observation. c-d) 433-photon source in ROSAT obs. RF500043A01 (8 GTIs). e-f) Simulated 300-photon periodic source with the GTIs of obs. RP600121N00. The dashed line indicates the location of the true period P=10⁴ s.
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In the text

$\begin{figure} \par\resizebox{8.8cm}{!}{\includegraphics{0220fg05.eps}} % \end{figure}$ Figure 5: Kuiper periodograms of EX Hya (a) and UW Pic (b). The grey lines show the 3953 s and 8047 s periods respectively. The dotted lines indicate the 10^-4 significance threshold. In a) the short-dash and long-dash lines show respectively the $3 \cdot 3953$ s and the possible 98-min period. In both panels the insets show the results of Rayleigh's test.
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In the text

$\begin{figure} \par\includegraphics[width=14.3cm,clip]{0220fg06.eps} \end{figure}$ Figure 6: Kuiper periodograms of the 28 candidates listed in Table 1. The candidate frequency is highlighted with a grey line. The horizontal dotted line is the 10^-4 significance limit corrected for the number of trials. Contamination related to the wobble frequency is indicated with a black circle. Contamination related to the revolution frequency is indicated with a black triangle. The numbers are the "ID'' column in Table 1.
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In the text

$\begin{figure} \resizebox{8.8cm}{!}{\includegraphics{0220fga1.eps}} % \end{figure}$ Figure A.1: Fractions of false-positives compared to the expectation for 7 different probability thresholds, from 10^-1 to 10^-7, and different sample sizes. The empty circles have been calculated using Eq. (3). The black symbols use different RNGs (see text).

In the text

$\begin{figure} \resizebox{8.8cm}{!}{\includegraphics{0220fgb1.eps}} % \end{figure}$ Figure B.1: Correction factor R for successive chunks of 1000 frequencies for two simulated 100-photon observations using the GTIs of obs. RP201045N00 a) and RP800035A01 b).

In the text

$\begin{figure} \resizebox{8.8cm}{!}{\includegraphics{0220fgb2.eps}} % \end{figure}$ Figure B.2: Correction factor R for the 30 sources from Table 1 as a function of N (a), $N_{\rm F}$ (b), and the on-time vs. total duration ratio (c). The dashed line is the best linear fit.

In the text

$\begin{figure} \par\resizebox{8.8cm}{!}{\includegraphics{0220fg01.eps}} % \end{figure}$	Figure 1: Domains in ${\it FPP}$ vs. Sample Size covered by the four formulae. The labels indicate the number of the equation used to calculate the probability. The structures in the dark grey area are due to the different validity criteria for even and odd numbers in Eq. (6)
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$\begin{figure} \par\resizebox{8.8cm}{!}{\includegraphics{0220fg03.eps}} % \end{figure}$	Figure 3: Ratio $R(k)=n_{{\rm eff}}/n$ as a function of k for five different "observations'': two continuous (20 and 200 photons) ones, and three corresponding to obs. `RP300093N00`, `RP300262N00`, and `RP700232N00` with 100, 1596, and 377 photons. The grey area shows the uncertainties for one of the five curves. The dashed line has a slope -1.
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$\begin{figure} \par\resizebox{8.8cm}{!}{\includegraphics{0220fg04.eps}} % \end{figure}$	Figure 4: Effect of the GTIs on Rayleigh's (top) and Kuiper's (bottom) tests. a-b) Simulated 1000 s 1000-photon observation. c-d) 433-photon source in ROSAT obs. `RF500043A01` (8 GTIs). e-f) Simulated 300-photon periodic source with the GTIs of obs. `RP600121N00`. The dashed line indicates the location of the true period P=10⁴ s.
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$\begin{figure} \par\resizebox{8.8cm}{!}{\includegraphics{0220fg05.eps}} % \end{figure}$	Figure 5: Kuiper periodograms of EX Hya (a) and UW Pic (b). The grey lines show the 3953 s and 8047 s periods respectively. The dotted lines indicate the 10^-4 significance threshold. In a) the short-dash and long-dash lines show respectively the $3 \cdot 3953$ s and the possible 98-min period. In both panels the insets show the results of Rayleigh's test.
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