Cyano radical emission at small spatial scales towards massive
  protostars
  The cyano radical (CN), one of the first detected interstellar molecular
species, is a key molecule in many astrochemical chains. Particularly, it is
detected towards molecular cores, the birth places of the stars, and it is
known that it is involved in the rich chemistry that takes place in these
sites. At present there are not so many studies about the emission of this
molecular species at small spatial scales towards massive young stellar
objects. Thus, we present a high-angular resolution CN study towards a sample
of massive protostars, with the aim of unveiling the spatial distribution at
the small scale of the emission of this radical in relation to the star-forming
processes. The interstellar CN has a strong emission line at the rest frequency
226874.764 MHz, thus, we search for observing projects in the ALMA database
regarding high-mass star-forming regions observed at Band 6. A sample of ten
high-mass star-forming regions were selected in base on that they present a
clear emission of CN at the mentioned frequency. We found that the CN traces
both molecular condensations and diffuse and extended gas surrounding them. In
general, the molecular condensations traced by the maximums of the CN emission
do not spatially coincide with the peaks of the continuum emission at 1.3 mm,
which trace the molecular cores where the massive stars born. Based on the
presence or lack of near-IR emission associated with such cores, we suggest
that our sample is composed by sources at different stages of evolution. The CN
is present at both, suggesting that this radical may be ubiquitous along the
different star formation stages, and hence it may be involved in different
chemical reactions occurring along the time in the formation of the stars.
Additionally, other complex molecules were detected towards the continuum peaks
of some of the analyzed cores.
