A background galaxy in the field of the \u3b2 Pictoris debris disk

Herschel images in six photometric bands show the thermal emission of the debris disk surrounding \u3b2 Pic. In the three PACS bands at 70\u2009\u3bcm, 100\u2009\u3bcm and 160\u2009\u3bcm and in the 250\u2009\u3bcm SPIRE band, the disk is well-resolved, and additional photometry is available in the SPIRE bands at 350\u2009\u3bcm and 500\u2009\u3bcm, where the disk is only marginally resolved. The SPIRE maps reveal a blob to the southwest of \u3b2 Pic, coinciding with submillimetre detection of excess emission in the disk. We investigated the nature of this blob. Our comparison of the colours, spectral energy distribution and size of the blob, the disk and the background sources shows that the blob is most likely a background source with a redshift between z = 1.0 and z = 1.6.Peer reviewed: YesNRC publication: Ye