3 The catalogue

We selected for our final source catalogue only detections with an existence likelihood ratio $LH_{\rm exist}\gt 10$, which is equal to a probability of existence $P\sim(1-\exp(-LH_{\rm exist}))\sim(1-4.5\ 10^{-5})$.We give the value for the extent only in case the extent likelihood ratio is $LH_{\rm extent}\ge10$.

A $90\%$ source error radius was calculated, adding quadratically a $5\hbox{$^{\prime\prime}$}$ systematic error.

$$P_{\rm e} = 2.1\times \sqrt{x_{\rm err}^2 + y_{\rm err}^2 + (5\hbox{$^{\prime\prime}$})^2}.$$ (2)

The positional error derived for large off-axis angles $\Delta$ $^{\gt}\hspace{-0.24cm}_{\sim}$30' may be somewhat underestimated due to the asymmetry of the point-spread-function. But the positional error should not be larger than $\sim1'$.

We catalogued all point-like and moderately extended sources found in this survey in Table 1. A small fraction ($\sim$9%) of catalogued sources may be false (artifacts due to the PSPC detector structure). The source positions were not corrected with respect to the positions of known standard sources (e.g. foreground stars or background active galactic nuclei (AGNs)) because it may easily introduce improper shifts in position. Column 1 gives the source catalogue number and Col. 2 the ROSAT source name. In Cols. 3 and 4 we list source positions, the right ascension (RA) and declination (Dec) for the epoch J2000 with the 90% confidence positional uncertainty (Col. 5). Column 6 gives the total count rate (with the $1\sigma$ errors). We list the soft (HR1) and the hard (HR2) hardness ratio (with $1\sigma$ errors) in Cols. 7 and 8, while in Col. 9 we present the source extent in cases where the likelihood ratio for extent is greater than 10. In Col. 10 is listed the likelihood ratio of existence ($LH_{\rm exist}$) and in Col. 11 the off-axis angle ($\Delta$) for the detection with the highest $LH_{\rm exist}$ from different bands. Columns 12 and 13 give the Einstein index (from the Wang & Wu 1992, catalogue) and the distance to the Einstein source. Columns 14, 15 and 16 list the stellar type, the magnitude of the Simbad identified star and the distance to the Simbad star. In Col. 17 we list the source class according to our classification scheme (Sect. 5, Table 3). In addition four sources are classified as SNRs although they have a smaller extent likelihood ratio as required from the classification. However, they coincide with SNRs detected with Einstein. In Col. 18 we give a refined classification for candidate AGN and hard X-ray binary. In Col. 19 we give some notes on either radio or optical identifications.

For the hard X-ray binary and the AGN class we have refined the classification scheme. We have taken the local Hydrogen column into account and from simulations of power-law slope -2.0 and -2.6 AGN spectra we have predicted hardness ratios which we compared with the measured hardness ratios. In case the classification was not unique we introduced the class AB in Table 1, Col. 18.

In Fig. 1 we show the spatial distribution of all 248 detections in the direction of the SMC overlaid on a merged exposure image. Only the central 45' of the field of view are considered for source detection.

  

Figure 1: Distribution of all X-ray detections in the field of the SMC drawn over integrated exposure map