The G292.0+1.8 pulsar wind nebula in the mid-infrared

摘要

Context. G292.0+1.8 is a Cas A-like supernova remnant thatcontains the young pulsar PSRJ1124-5916 powering a compacttorus-like pulsar wind nebula visible in X-rays. A likely counterpartto the nebula has been detected in the optical VRI bands. Aims. To confirm the counterpart candidate nature, we examinedarchival mid-infrared data obtained with the Spitzer Space Telescope. Methods. Broad-band images taken at 4.5, 8, 24, and 70m were analyzed and compared with available optical and X-ray data. Results. The extended counterpart candidate is firmly detected in the 4.5 and 8mbands. It is brighter and more extended in the bands than in theoptical, and its position and morphology agree well with thecoordinates and morphology of the torus-like pulsar wind nebula inX-rays. The source is not visible in 24 and 70mimages, which are dominated by bright emission from the remnant shelland filaments. We compiled the infrared fluxes of the nebula, whichprobably contains a contribution from an unresolved pulsar in itscenter, with the optical and X-ray data. The resulting unabsorbedmultiwavelength spectrum is described by power laws of significantlysteeper slope in the infrared-optical than in X-rays, implying adouble-knee spectral break between the optical and X-rays. The 24 and70mflux upper limits suggest a second break and a flatter spectrum at thelong wavelength limit. These features are common to two other pulsarwind nebulae associated with the remnants B0540-69.3 and 3C58 andobserved in all three ranges. Conclusions. The position, morphology, and spectral propertiesof the detected source allow us to confirm that it is theinfrared-optical counterpart to both the pulsar and its wind nebulasystem in the G292.0+1.8 supernova remnant. Key words: ISM: supernova remnants - pulsars: individual: PSRJ1124-5916 - stars: winds, outflows - infrared: general - radiationmechanisms: non-thermal - ISM: individual objects: G292.0+1.8