47 U The alternative counterpart is 0.7arcsec more distant and 0.8mag fainter,
 47    although more stellar.
 56 U The alternative counterpart is 0.7mag fainter and much more diffuse, 
 56    although 0.3arcsec closer.
 57 U The alternative counterpart is 1.7mag fainter and 0.3arcsec more distant. 
 57    Neither counterpart is particularly close to the Chandra centroid but the
 57    source is 10.7' from the Chandra axis.
 85 P The alternative counterpart is 0.9mag fainter and 1.6arcsec more distant.
 95 P The alternative candidate is 3.4mag fainter and much more 
 95    distant (1.6arcsec).
102 U In this case the identification is completely uncertain. The alternative 
102    candidate is 0.3mag brighter, but 0.25arcsec more distant, and is less 
102    stellar.
115 U Both candidates are very faint (26mag) and so could be chance 
115    coincidences. The alternative candidate is 1.3arcsec more distant.
122 P The alternative candidate is 0.5mag fainter, more diffuse, and 0.9arcsec 
122    more distant.
130 U The identification may be with a cluster. The alternative candidate is 
130    0.2mag brighter, but 0.7arcsec more distant.
149 U The alternative candidate is 0.9mag brighter but 0.8arcsec more distant.
154 P The alternative candidate is 1.3mag fainter, and 1.4arcsec more distant.
162 U Both candidates are at similar distances from the Chandra centroid. The 
162    alternative candidate is 1.3mag fainter. The identification may, however,
162    be with a cluster as other objects are nearby.
170 U The alternative candidate is 1.6arcsec more distant and 0.4mag fainter.
173 U The alternative candidate is 1.5arcsec more distant and 3.5mag fainter.
188 U SExtractor finds no candidate within 2arcsec. However, examination of the 
188    optical image shows a bright galaxy whose centre is over 3arcsec to the 
188    north-west. That is too far to be a reasonable identification. However, 
188    to the south-east, and also to the north-west of the galaxy, there are 
188    bright components. We cannot tell if these two components are part of the
188    same structure, e.g. a bright disc, seen edge on, or whether they are 
188    separate objects, e.g. QSOs. The south-east component lies very close to 
188    the Chandra centroid and so its position is listed in Table 2.
192 U The identification may be with a cluster. The nominally primary candidate 
192    is 1.2arcsec closer but 1.2mag fainter.
200 U This source is almost on-axis so its position will be very accurate. Hence
200    we list, as the primary identification, an object which is 2mag fainter, 
200    but 1.2arcsec closer to the Chandra centroid, than the alternative 
200    candidate.
202 U The alternative candidate is 4mag fainter and 0.7arcsec more distant.
204 U Both candidates have similar magnitudes but the primary candidate 
204    is 1.6arcsec closer.
210 U There are two almost equally likely candidates, at similar distances. On 
210    the basis that it is a relatively bright radio source we list the 
210    fainter, by 2.8mag, and more stellar, as the slightly more likely 
210    candidate.