HI line observations of 2MASS galaxies in the Zone of Avoidance - Astrophysics > Cosmology and Nongalactic AstrophysicsReport as inadecuate

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Abstract: A pilot survey has been made to obtain 21cm HI emission line profiles for 197objects in the Zone of Avoidance ZoA that were classified as galaxies in the2MASS all-sky near-infrared Extended Source Catalog 2MASX. 116 of the sourceswere observed using the Nancay radio telescope, in the 325 to 11,825 km-srange, and the other 81 sources were observed at Arecibo in the -500 to 11,000km-s range, and for 9 also in the 9,500 to 21,000 km-s range. Global HI lineparameters are presented for the 22 and 29 2MASX objects that were detected atNancay and Arecibo, respectively, as well as upper limits for the undetected2MASX objects. Whereas object 2MASX J08170147-3410277 appears to be a verymassive galaxy with an HI mass of 4.6 x 10E10 Msun, it is clear that only radiosynthesis HI imaging observations will allow a firm conclusion on this.Overall, the global properties of the detected galaxies match those of otherZoA HI surveys. Although the detections are as yet too sparse to give furtherinsight into suspected or unknown large-scale structures in the ZoA, theyalready indicate that an extension of the present pilot survey is bound toquantify filaments, clusters, and voids behind this part of the Milky Way. Itis shown that the number of candidate 2MASS-selected ZoA galaxies to beobserved in HI could have been reduced by about 15% through examination ofcomposite near-infrared images and the application of extinction-correctednear-infrared colour limits. Present results confirm that the Galacticextinction values from Schlegel et al. 1998 are valid for latitudes above|b|=5 degrees, but increasingly less so for lower latitudes.

Author: W. van Driel, S.E. Schneider, R.C. Kraan-Korteweg, D. Monnier Ragaigne

Source: https://arxiv.org/


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