We observed the middle-aged radio pulsar B0656+14 with a CCD detector at the 6-m telescope. Broadband BVRI images show the following magnitudes of the pulsar counterpart: B = 24.85 (+0.19, -0.16),\ V = 24.90 (+0.16, -0.14),\ R = 24.52 (+0.12, -0.11),\ I = 23.81 (+0.27, -0.21). We fitted the UV-optical (space + ground-based) data with a two-component model which combines a power law (non-thermal component) with a thermal spectrum emitted by the neutron star surface. The power law component, with the energy power-law index alpha =1.5 (+1.1,-1.2), dominates in the observed range. Constraints on the thermal component correspond to the Rayleigh-Jeans parameter Gequiv T_6(R10/d500)(2) =4.1 (+2.1, -4.1), where T=10(6T_6) K is the brightness temperature, R_infty = 10 R10 km is the neutron star radius as seen by a distant observer, and d=500 d500 pc is the distance. The shape of the optical-UV spectrum of PSR B0656+14 differs considerably from those observed from other pulsars: the middle-aged Geminga and young Crab, Vela.
Astronomy and Astrophysics
- Pub Date:
- May 1998
- PULSARS: INDIVIDUAL: PSR B0656+14;
- STARS: PRE-MAIN SEQUENCE;
- STARS: NEUTRON;
- 11 pages, 8 Postscript figures, Latex, l-aa.sty and psfig.sty included, submitted to Astronomy and Astrophysics