Multiple transitions of singly-deuterated ammonia was detected in Sagittarius B2 using the Karl G. Jansky Very Large Array (VLA) with a resolution of 3” and the Australia Telescope Compact Array (ATCA) with a resolution of 10”. Deuterated ammonia was detected in two sources in the Northern core of Sgr B2. The most commonly known source, the Large Molecule Heimat, had a velocity of ~61 km/s. The other source we designate as h had a velocity of ~73 km/s. Multiple transitions of ammonia and the isotopologue 15-ammonia were detected as well. NH3 is a useful tracer of temperature, but in Sgr B2 the transitions were too optically thick to measure accurately. Instead15NH3 was utilized to find a rotation temperature and thus kinetic temperature. The temperature of h was higher than that of LMH, which is unexpected, because LMH is more chemically complex and contains an embedded ultra-compact HII region, suggesting it is the more evolved source, and should have a warmer temperature. The column densities of 15NH3 and NH2D were used to find the deuterated fractions in each source. The ratio of 14N to 15N previously measured in Sgr B2 was used to approximate the amount of ammonia. The deuteration fraction was found to be ~40x higher in h than LMH, which is surprising given h is the hotter source and fractionation reactions that lead to higher deuteration of molecules are favored in cooler temperatures. We will discuss possible explanations for these discrepancies.

Location of deuterated ammonia in Sagittarius B2

249th National Meeting (2015)

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