New high resolution VLA mosaic at 1.4 GHz of the SNR Puppis A

CASTELLETTI G.; DUBNER G.; GOLAP K.; GOSS W. M.

Pucón

Simposio; XI IAU Regional Latin American Meeting of Astronomy; 2005

Unión Internacional de Astronomía

We present new observations at 1.4 GHz of the supernova remnant (SNR) Puppis A made with the VLA in the hybrid DnC and CnB configurations (in 2003 and 2004, respectively). We observed this extended remnant (about 55´ diameter) applying a mosaicking technique to combine 39 different pointings. The data were reduced using the AIPS++ software package. The multiscale clean method was used to deconvolve the image. The interferometric image was combined with single dish data extracted from the Parkes Southern Galactic Plane Survey (McClure-Griffiths et al. 2001, AJ, 551, 394) following a feathering technique which involves Fourier transforming of both the single dish and interferometric data onto identical grids. The new image produced by uniformly weighted visibility data, has a final angular resolution of 34 arcsec × 16 arcsec and an rms noise level of 0.5 mJy/beam; the improvement represents a factor of two in angular resolution and almost ten times in sensitivity compared to the best previous image of Puppis A at 1515 MHz (Dubner et al. 1991, AJ, 101, 1466; HPBW 77 arcsec × 43arcsec, rms noise 3 mJy/beam). For the first time a highly structured border encircling a diffuse, almost featureless interior was revealed in Puppis A. In particular the northern half of Puppis A displays a wealth of structure along the periphery consisting of short arcs that appear to be oriented rather perpendicular to the shock front on the northeast quadrant, but tangential to it on the northweast side.