2019MNRAS.484.2089R

We present a morphological and physical analysis of a giant molecular cloud (GMC) using the carbon monoxide isotopologues (¹²CO, ¹³CO, C¹⁸O ³P₂ - ³P₁) survey of the Galactic Plane (Mopra CO Southern Galactic Plane Survey), supplemented with neutral carbon maps from the HEAT telescope in Antarctica. The GMC structure (hereinafter the ring) covers the sky region 332° < l < 333° and b = ±0.5° (hereinafter the G332 region). The mass of the ring and its distance are determined to be ∼2×10⁵ M_☉ and ∼3.7 kpc from the Sun, respectively. The dark molecular gas fraction - estimated from the ¹³CO and [C I] lines - is ∼17 per cent for a CO T_ex between [10,20 K]. Comparing the [C I] integrated intensity and N(H₂) traced by ¹³CO and ¹²CO, we define an X_CI⁸⁰⁹ factor, analogous to the usual X_co, through the [C I] line. X_CI⁸⁰⁹ ranges between [1.8,2.0] ×10²¹ cm^–2 K^–1 km^–1 s. We examined local variation in X_co and T_ex across the cloud, and find in regions where the star formation activity is not in an advanced state, an increase in the mean and dispersion of the X_co factor as the excitation temperature decreases. We present a catalogue of C¹⁸O clumps within the cloud, and report their physical characteristics. The star formation (SF) activity ongoing in the cloud shows a correlation with T_ex, [C I], and CO emissions, and anticorrelation with X_co, suggesting a North-South spatial gradient in the SF activity. We propose a method to disentangle dust emission across the Galaxy, using H I and ¹³CO data. We describe virtual reality and augmented reality data visualization techniques, which open new perspectives in the analysis of radio astronomy data.