Molecular Distribution in the Central Region of M87

The central region of M87 has been observed by the Atacama Large Millimeter/submillimeter Array (ALMA) several times to resolve its molecular cloud distribution. We present the ALMA CO(1-0), CO(2-1), and CO(3-2) observations of the M87 circumnuclear region. The CO(1-0) shows emission as well as molecular absorption features toward its nucleus, indicating the existence of cold molecular clouds/gas. ALMA imaging of the CO(1-0) observations show the distribution of molecular clouds toward the nucleus of M87 with a radius of similar to 105 pc. The clouds seen in the CO(1-0) are moving with very high velocity and have an apparent motion in the range of -1000 to 3600 km s-1 relative to the central supermassive black hole, which has a systemic velocity of similar to 1266 km s-1. The molecular gas mass was estimated to be about 1.08 +/- 0.64 x 107 M circle dot in the central 210 pc of M87. We calculated the optical depths using the absorption lines of the CO(1-0) and CO(2-1). The excitation temperature was estimated to be similar to 7.133 +/- 0.03 K using the optical depth ratio of the CO(2-1) to CO(1-0). We also found the line-of-sight column density to be similar to 2.25 x 1015 cm-2, which corresponds to a hydrogen column density of similar to 0.28 x 1020 cm-2.