Figure 1: The deviation in RA and Dec between
X-ray positions (LECS, MECS1, MECS2, MECS3) and optical positions. The
short-dashed circle has a radius of 30 arcsec. Note that coordinates differences
have been computed subtracting the X-ray value from the optical one and
that RA differences are corrected by the factor cos(Dec). "Delta RA" values
represent therefore the true separation in the sky.