Speaker: Arshia Maria Jacob
Title : CH as a tracer for molecular hydrogen: forming synergies between its FIR and radio fingerprints
The existence of “CO-dark” molecular hydrogen has motivated the search
for alternative chemical tracers for H2 in diffuse clouds. A search that
resulted in the use and establishment of interstellar hydrides such as
HF, CH and OH as tracers for the same. CH stands out from its hydride
counterparts for a number of reasons and the aim of this work is to
reveal its power as a suitable tracer by studying transitions of CH at
different wavelengths. However, the plot thickens as the interpretation
of the ground state radio lines of CH display characteristics of a weak
maser due to anomalous excitation.
In this talk I would like to discuss the synergies formed between the
FIR and radio spectra of CH towards W49N and W51 and the various methods
employed in deriving parameters like column density and the physical and
excitation conditions that prevail in the surrounding medium.