Exploring molecular complexity with alma (EMoCA): high-angular-resolution observations of sagittarius B2(N) at 3 mm

Abstract

Sagittarius (Sgr for short) B2 is the most massive and luminous star-forming region in our Galaxy, located close to the Galactic Center. We have carried out a molecular line survey with the IRAM~30~m telescope toward its two major sites of star-formation, Sgr~B2(M) and (N).footnote{A. Belloche et al., textit{A&A} textbf{559} (2013) Art. No. A47.} Toward the latter source, which is particularly rich in Complex Organic Molecules (COMs), we detected three molecules for the first time in space, aminoacetonitrile, ethyl formate, and textit{n}-propyl cyanide. We have recently obtained ALMA data of Sgr~B2(N) between $sim$84 and $sim$111~GHz within Cycle~0 and one additional setup up to 114.4~GHz within Cycle~1. At angular resolutions of $1.8''$ and $1.4''$, respectively, the two main hot cores, the prolific Sgr~B2(N-LMH) (or Sgr~B2(N)-SMA1) and the likely less evolved Sgr~B2(N)-SMA2 are well separated, and line confusion is reduced greatly for the latter. As a consequence, we have been able to identify the first branched alkyl molecule in space, textit{iso}-propyl cyanide, toward Sgr~B2(N)-SMA2.footnote{A. Belloche et al., textit{Science} textbf{345} (2014) 1584.} Our ongoing analyses include investigations of cyanides and isocyanides, alkanols and thioalkanols, and deuterated molecules among others. We will present some of our results