SIMBAD references

PSR J1811-1736 (P=104ms) is a binary pulsar in a highly eccentric orbit (P_orb= 18.8 d) around an unidentified companion. Here, an optical follow-up investigation of the pulsar field, performed using photographic plates from the UK-SERC Equatorial red survey, is reported. No object is detected at the pulsar position down to R∼22. At the pulsar distance of 6kpc, this implies, for a likely value of A_R (≃5), an absolute magnitude M_R≥3 for the companion star. Although the present upper limit is deep enough to rule out a red giant, it still leaves open the possibility of a main sequence star or a red dwarf companion. Deeper optical observations are thus required to investigate the presence of white dwarf or a neutron star.