The Arecibo Galactic Chemistry Survey Chris Salter Arecibo

The Arecibo Galactic Chemistry Survey Chris Salter Arecibo Observatory (National Astronomy & Ionosphere Center)

Molecular-Line Studies CH 2 NH in Arp 220 H 2 O maser in host galaxy of QSO J 0414+0534 (z=2. 64) monitored at 6 week intervals Top Formaldehyde Absorption and (bottom) excited-line OH maser emission in LIRG, NGC 660 CH main line at 724 MHz in W 51

An Arecibo Galactic Chemistry Survey • First proposal made in 2007 to make a 1 – 10 GHz survey of a number of representative Galactic sources using the Mock Spectrometer in single-pixel mode. • Unbiased spectral line surveys → information needed to characterize physical and chemical conditions. • The full range 1 – 10 GHz is relatively unexplored for Galactic sources and many complex molecules have lines at λ < 3 cm. • “Line confusion” is very much less in this range than at millimeter wavelengths.

Precursor Observations • Observations made in Oct-Nov 2008. • Targets were star-forming region, NGC 2264, and C-rich, evolved PPN, CRL 618. • The single-pixel Mock mode was not ready, so the precursor observations were made with the WAPPs. • A shallow, but full, 1 – 10 GHz coverage was made for both objects with a velocity resolution of 0. 7 kms-1. Excited satellite line OH maser in PPN, CRL 618 Methanol in NGC 2264 -IRS 1 HC 3 N in NGC 2264 -IRS 1

Test Set-Up: Oct 5 th 2009 • A second proposal was submitted in Feb. 2009 to make a full 1 – 10 GHz survey of the ultra-compact source W 51 e 2 in W 51 IRS 1. This was graded 'A', and awarded 112 hr. • A preliminary version of the singlepixel Mock mode was made available by Phil Perillat this fall. • An hour's test time was used to try out a first AGCS C-band set-up for the Mocks on October 5 th 2009.