... band

All the count rates listed here and hereafter have already been corrected for the enclosed energy fraction and the vignetting.

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... observations

This source was not discussed in Soria & Kong (2002) because in that paper we focussed only on transient sources newly detected by XMM

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... AGN

Two candidate "ultra-luminous'' sources in the field of nearby galaxies have recently been recognised as background AGN (Masetti et al. 2003; Foschini et al. 2002). The possibility that CXOU J13651.1+154547 is a background object was discussed by Krauss et al. (2003), but considered unlikely in the absence of any radio or optical counterpart.

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... bmc

The bmc model (Shrader & Titarchuk 1999) describes the thermal or bulk motion Comptonization of a blackbody seed-photon component.

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... comptt

Comptt (Titarchuk 1994) approximates the seed-photon input spectrum with the Wien tail of the blackbody spectrum. Thus, it is simpler but less accurate than the bmc model.

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... detector

The conversion between the XMM-Newton and Chandra count rates in the three bands depends of course on the assumed spectral model and absorption, but these variations are small for the range of column densities and temperatures considered in Table 2. We converted the colours using the correct response matrices generated by the CIAO and SAS software, rather than the default (pre-launch) responses from PIMMS.

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... 1252

The GCN archive is at http://gcn.gsfc.nasa.gov/gcn3_archive.html.

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