PSR B1931+24 is the first intermittent radio pulsar discovered to date , characterized by a 0.8 s pulsation which turns on and off quasi-periodically every \sim 35 days , with a duty cycle of \sim 10 % .
We present here X–ray and optical observations of PSR B1931+24 performed with the Chandra X-ray Observatory and Isaac Newton Telescope , respectively .
Simultaneous monitoring from the Jodrell Bank Observatory showed that this intermittent pulsar was in the radio–on phase during our observations .
We do not find any X–ray or optical counterpart to PSR B1931+24 , translating into an upper limit of \sim 2 \times 10 ^ { 31 } erg s ^ { -1 } on the X–ray luminosity , and of g ^ { \prime } > 22.6 on the optical magnitude .
If the pulsar is isolated , these limits can not constrain the dim X-ray and optical emission expected for a pulsar of that age ( \sim 1.6 Myr ) .
We discuss the possibility that the quasi–periodic intermittent behavior of PSR B1931+24 is due to the presence of a low mass companion star or gaseous planet , tight with the pulsar in an eccentric orbit .
In order to constrain the parameters of this putative binary system we re-analysed the pulsar radio timing residuals and we found that ( if indeed hosted in a binary system ) , PSR B1931+24 should have a very low mass companion and an orbit of low inclination .