The HiParkes Zone of Avoidance Survey: The Northern Extension

We present the results of the northern extension of the HI Parkes Zone ofAvoidance Survey, a blind HI survey utilizing the multibeam receiver on theParkes 64-m telescope. In the two regions studied here, l=36 to 52 deg. andl=196 to 212 deg., |b|<5 deg., we have detected 77 HI galaxies, twenty of whichhave been previously detected in HI. The survey has a median rms noise of 6.0mJy/beam and is complete to a mean flux density of 22 mJy. We have searched formultiwavelength counterparts to the 77 galaxies detected here: 19, 27, and 11have a likely optical, 2MASS, and IRAS cataloged counterpart, respectively. Afurther 16 galaxies have likely visible counterparts on the Digitized SkySurvey. The detection of these 77 galaxies allows a closer inspection of thelarge-scale structures in these regions. We see several filaments crossing theGalactic plane, one of which appears to be the continuation of a sine-wave likefeature that can be traced across the whole southern sky. An analysis of the HImass function suggests that the regions studied here may be underdense. Oneparticularly noteworthy galaxy is HIZOA J0630+08 (l,b = 203 deg., -0.9 deg.)with a velocity of 367 km/s. We suggest that it belongs to the nearby OrionGroup which includes a small number of dwarf galaxies. The newly detectedgalaxies improve our understanding of the properties of several voids, such asthe Orion, Gemini, and Canis Major Voids.Comment: 18 pages, 15 figures, 6 tables, accepted for publication in The Astronomical Journal (January 2005 issue