Sample of LMXBs in the Galactic bulge - I. Optical and near-infrared constraints from the Virtual Observatory

We report on the archival optical and near-infrared observations of six low-mass X-ray binaries situated in the Galactic bulge. We process several recent Chandra and XMM-Newton as well as Einstein data sets of binary systems suspected to be ultracompact, which give us arcsec-scale positional uncertainty estimates. We then undertake a comprehensive search in existing archives and other Virtual Observatory resources in order to discover unpublished optical/near-infrared data on these objects. We find and analyse data from European Southern Observatory Archive and UKIRT Infrared Deep Sky Survey on SLX 1735-269, 3A 1742-294, SLX 1744-299, SLX 1744-300, GX 3+1 and IGR J17505-2644 systems and publish their finding charts and optical flux constraints in this paper, as well as simple estimates of the physical parameters of these objects.