First detection of methyl formate in the hot molecular core IRAS 18566+0408

The studies of the complex molecular emission lines in the millimeter and submillimeter wavelengths towards the hot molecular cores reveal valuable details about the chemical complexity in the interstellar medium (ISM). We presented the first detection of the rotational emission lines of the complex organic molecule methyl formate (CH3OCHO) towards the hot molecular core region IRAS 18566+0408 using the high-resolution Atacama Large Millimeter/Submillimeter Array (ALMA) band 3 observation. The estimated column density of CH3OCHO using the rotational diagram analysis was (4.1 +/- 0.1)x 10(15) cm(-2) with a rotational temperature of 102.8 +/- 1.2 K. The estimated fractional abundance of CH3OCHO relative to hydrogen (H-2) towards the IRAS 18566+0408 was 3.90x10(-9). We noted that the estimated fractional abundance of CH3OCHO is fairly consistent with the simulation value predicted by the three-phase warm-up model from Garrod (2013). We also discussed the possible formation mechanism of CH3OCHO towards the IRAS 18566+0408.