Deep optical observations of the gamma-ray pulsar PSR J0007+7303 in the CTA 1 supernova remnant

作者：Mignani R P^*; de Luca A; Rea N; Shearer A; Collins S; Torres D F; Hadasch D; Caliandro A

来源：Monthly Notices of the Royal Astronomical Society, 2013, 430(2): 1354-1358.

DOI：10.1093/mnras/stt013

• stars: neutron
• pulsars: individual: PSR J0007+7303

The Fermi Large Area Telescope discovered the time signature of a radio-silent pulsar coincident with RX J0007.0+7302, a plerion-like X-ray source at the centre of the CTA 1 supernova remnant. The inferred timing parameters of the gamma-ray pulsar PSR J0007+7303 (P = 315.8 ms;. (P) over dot similar to 3.6 x 10(-13) s s(-1)) point to a Vela-like neutron star, with an age comparable to that of CTA 1. The PSR J0007+7303 low distance (similar to 1.4 kpc), interstellar absorption (A(V) similar to 1.6), and relatively high energy loss rate ((E) over dot similar to 4.5 x 1035 erg s-1), make it a suitable candidate for an optical follow-up. Here, we present deep optical observations of PSR J0007+7303. The pulsar is not detected in the Gran Telescopio Canarias images down to a limit of r' similar to 27.6 (3 sigma), the deepest ever obtained for this pulsar, while William Herschel Telescope images yield a limit of V similar to 26.9. Our r' -band limit corresponds to an optical emission efficiency eta(opt) = L-opt/(E) over dot less than or similar to 9.4 x 10(-8). This limit is more constraining than those derived for other Vela-like pulsars, but is still above the measured optical efficiency of the Vela pulsar. We compared the optical upper limits with the extrapolation of the XMM-Newton X-ray spectrum and found that the optical emission is compatible with the extrapolation of the X-ray power-law component, at variance with what is observed, e.g. in the Vela pulsar.

• 出版日期2013-4