2. Discrete sources towards the MCs

2.1. Discrete radio sources towards the LMC

Catalogues of discrete radio sources towards the LMC at six radio frequencies are presented in Papers IV and IVa of this series and in Filipovic (1996). The total number of catalogued radio sources is 483: 192 at 1.40 GHz, 119 at 2.30 GHz, 338 at 2.45 GHz, 373 at 4.75 GHz, 332 at 4.85 GHz and 212 at 8.55 GHz. As clear radio detections, we listed only radio sources that are stronger than 5 or seen at two or more frequencies.

2.2. Discrete X-ray sources towards the LMC

A catalogue of RASS X-ray sources towards the LMC is published in Pietsch et al. (in preparation). In addition to this catalogue we compared Parkes radio and RASS images and found eight additional X-ray sources which are not catalogued in Pietsch et al. (in preparation). These eight sources are listed in Table 1 (click here) which follows the format of the table in Pietsch et al. (in preparation). Source positions, RA and Dec, are given in J2000 coordinates in Col. 2 and Col. 3, respectively. Positional error is given in Col. 4 and the exposure time in Col. 5. The definitions of likelihood existence (LH) (Col. 6), count rate (Col. 7), hardness ratios (HR1) and (HR2) (Cols. 8 and 9, respectively) are the same as in Pietsch et al. (in preparation). Count rates of the sources have been derived for the five standard energy bands: "broad'' (0.11-2.4 keV), "soft'' (0.11-0.41 keV), "hard'' (0.52-2.01 keV), "hard1'' (0.52-0.90 keV) and "hard2'' (0.91-2.01 keV). HR1 is defined as and HR2 is defined as . LH is the maximum likelihood of source existence and may be converted into probabilities via . That means that LH=9.7 corresponds to about four Gaussian sigma significance. All sources have .

   

(1) (2) (3) (4) (5) (6) (7)       (8)                (9)                (10)       

No. RA (2000) Dec (2000) Exposure LH Count Rate HR1 HR2 Other Names

0h 0m 0s0  (s) (cts ks^-1)

9001 04 28 36.7 -67 49 10 19 1420 13

9002 04 46 09.0 -72 04 53 40 1019 10

9003 04 54 21.3 -68 00 11 30 2028 08

9004 05 13 42.2 -67 24 19 29 2293 08 N 30; DEML112

9005 05 24 10.0 -66 20 54 21 2110 11 N 46; DEML162

9006 05 28 49.3 -65 39 41 26 3250 08

9007 05 34 59.3 -64 38 27 47 1827 09

9008 05 38 34.7 -69 06 06 37 2199 19 30 Dor; N 157A

Table 1: Additional LMC RASS sources found after comparison with Parkes radio data (Paper IV) and not listed in Pietsch et al. (in preparation). Entries in this table follow the format of Pietsch et al. (in preparation)

We believe that a number of other radio sources could have X-ray counterparts, but because most of these sources belong to confused regions, we could not resolve them in the RASS. We expect that these "confused'' sources will be resolved in the ROSAT-pointed observations (PSPC) which have better resolution.

We use the common area of the radio and X-ray surveys defined in Paper IV of 100 square degrees between to and  to . In this area we expect about eight sources to have positional coincidence by chance alignment, based on the number of sources at each frequency and  search criterion for coincidence. Also, we have checked this number of chance coincidences by simulation. We shifted one set of positions in either coordinate by 5 to   and found the number of spurious coincidences to be over repeated trials.

We now have 325 RASS sources towards the LMC field defined by the radio surveys (see Sect. 2.1) and we compare these with 483 radio sources in the same field.

2.3. Discrete radio sources towards the SMC

The new catalogues of radio sources in the SMC at five radio frequencies: 1.42 GHz (86 sources), 2.45 GHz (107 sources), 4.75 GHz (99 sources), 4.85 GHz (187 sources) and 8.55 GHz (41 sources) are given in Paper V and in Filipovic (1996). There is a total of 224 radio sources towards the SMC. As clear radio detections, again we listed only radio sources that are stronger than 5 or seen in at least two frequencies.

2.4. Discrete X-ray sources towards the SMC

A catalogue of the ROSAT PSPC sources in the field of the SMC is published in Kahabka et al. (in preparation) and combines the results of nine pointed observations. These observations (exposure corrected) of the SMC were carried out with the ROSAT PSPC detector in the energy range 0.1-0.4 keV and 0.4-2.4 keV.

Using the common area of the radio and X-ray surveys ( square degrees between to and Dec to ) and the search criterion, we expect about nine sources to have positional coincidence by chance alignment. In this area, there are 86 radio sources from our Parkes radio surveys and they are compared with 248 X-ray PSPC sources from Kahabka et al. (in preparation).