Astron. Astrophys. 359, 113-130 (2000)

Footnotes

1. On-line version at http://simbad.u-strasbg.fr/Simbad .

2. On-line version on the ESO site: http://arch-http.hq.eso.org/cgi-bin/dss .

3. When two possible counterparts are in the error box (this happens only three times, see the finding charts in Appendix B, and Table B1 notes), we take the more luminous in the J-band, since the X-ray luminosity of TTS is correlated with the J-band luminosity (see CMFA, and below 3.2, 7.2).

4. 4 were already PSPC Class III source candidates, and are confirmed by ISOCAM , which detected no IR excess; 3 were probably detected by the PSPC , but due to its lower angular resolution the optical or IR counterpart was uncertain (see Col. 2 of Table B1 and attached notes); 6 are genuine new X-ray detections, probably resulting from variability.

5. Noted in CMFA.

6. 22 Class II sources and 19 Class III sources; for the core F observation we take the mean X-ray luminosity in Col. 13 of Table B1.

7. Version available at http://www.astro.psu.edu/statcodes .

8. In addition one should note that the RASS includes the soft band (0.1-1 keV), which is more sensitive to the extinction than the hard band (1-2.4 keV) taken by CMFA.

9. We took for the HRI field radius, because one of our sources (ROXRF31=SR9), is detected up to this angle from the axis in the Core F field.

10. We have excluded three new ISOCAM Class II sources for which we have only the K magnitude, and thus no estimate. for these sources must be small, and/or high, which implies a high upper limit on the intrinsic . This does not affect the statistical results.

11. When the YSO is in both Core A and Core F field, we use the longer Core F field exposure to estimate the count rate upper limit. using the EXSAS command COMPUTE/UPPER_LIMITS, and we use the extinction estimate from Bontemps et al. (2000) to compute the corresponding limit on the intrinsic X-ray luminosity.

12. We note that this method attributes a larger X-ray luminosity to the TTS having X-ray luminosities below the - correlation. By this effect X-ray undetected TTS can be put above the HRI detection threshold, but this concerns only 5 cases, see Fig. 6.

13. A few faint sources were however detected in spite of being below the nominal HRI detection threshold: they were probably in an X-ray flaring state at the time of the observations. In particular ROXRF32 = GY238, far below the HRI detection threshold, was detected only in the third Core F exposure, which supports this interpretation.

14. A larger FWHM must be used because there are fewer Class III sources than Class II sources and because they are less clustered.

15. The relative differences between these luminosities, and the bolometric corrected ones from spectral types are lower than .

16. In the core F image #3, many 1-15 channel detections with high were not found in the 3-8 channel band. Thus, we decided to take channels 2-8 instead of 3-8 in the three exposures. This third observation was the last of our program, one year after the Core A observation (see Table 1). According to Prestwich et al. (1998), the mean pulse height decreases by 0.5 channels year^-1: this effect might explains why we must decrease the lower channel boundary from 3 to 2. The upper channel boundary seems to be less sensitive, probably due to fewer counts in upper channels (see David et al. 1997).

17. The "legal" designation for a new ROSAT source is RXJHHMMSS.s DDMMSS, where J stands for coordinates in J2000 and s is the cut (not rounded) decimal value. Our tables do not use this notation for simplicity in the discussion, but the correct designation is easy to reconstruct from the position given if required. For example, ROXRF14 = ROXs20B = RXJ162714.9-245140.

18. Note that X-ray source 9B of Kamata et al. (1997) is in fact ROXR1-45 of CMFA.

© European Southern Observatory (ESO) 2000

Online publication: June 30, 2000
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