The Virgo High-Resolution CO Survey: I. CO Atlas

• Published in: Publications of the Astronomical Society of Japan 2003-02, Vol.55 (1), p.17-58
• Main Authors: Sofue, Yoshiaki, Koda, Jin, Nakanishi, Hiroyuki, Onodera, Sachiko, Kohno, Kotaro, Tomita, Akihiko, Okumura, Sachiko K.
• Format: Article
• Language: English
• ISSN: 0004-6264; 2053-051X
• DOI: 10.1093/pasj/55.1.17

We present the results of the Virgo high-resolution CO survey (ViCS) obtained with the Nobeyama Millimeter-wave Array (NMA). This survey was made during the course of a long-term project at Nobeyama from 1999 December through 2002 April. The objects were selected from Virgo cluster members, while considering the CO richness from the single-dish flux, mild inclination, and a lack of strong tidal perturbations. The central ${1{}^{\mathrm {\prime }}}$ regions ( $\sim 4.7 \,\mathrm{kpc}$ ) of 15 spiral galaxies were observed with resolutions of ${2{}^{\mathrm {\prime \prime }}} \hbox{-} {5{}^{\mathrm {\prime \prime }}}$ and $10 \hbox{-} 20 \,\mathrm{km} \,\mathrm{s}^{-1}$ , and sensitivities of $\sim 20 \,\mathrm{mJy} \,\mathrm{beam}^{-1}$ for a $10 \,\mathrm{km} \,\mathrm{s}^{-1}$ channel. The objects lie at the same distance of the Virgo cluster (16.1 Mpc), which is advantageous for comparisons among individual galaxies. We describe the details of observations and data reduction, and present an atlas of integrated CO intensity maps, velocity fields and position–velocity diagrams along the major axes. The molecular gas morphology in the Virgo galaxies shows a wealth of variety, not specifically depending on the Hubble types. Several galaxies show a strong concentration of gas in the central few kpc region, where the CO morphology shows either a “single-peak” or a “twin-peaks”. The morphology of more extended CO components can be classified into “arm-type”, “bar-type”, and “amorphous-type”.