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70 th International Symposium on Molecular Spectroscopy June 2015 First Scientific Observations with the New ALMA Prototype Antenna of the Arizona Radio.

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Presentation on theme: "70 th International Symposium on Molecular Spectroscopy June 2015 First Scientific Observations with the New ALMA Prototype Antenna of the Arizona Radio."— Presentation transcript:

1 70 th International Symposium on Molecular Spectroscopy June 2015 First Scientific Observations with the New ALMA Prototype Antenna of the Arizona Radio Observatory: HCN and CCH in the Helix Nebula Lucy M. Ziurys and Deborah R. Schmidt Dept. of Astronomy, Dept. of Chemistry Arizona Radio Observatory University of Arizona

2 70 th International Symposium on Molecular Spectroscopy June 2015 In January 2015, “test” observations began at the new ARO 12 m ….

3 70 th International Symposium on Molecular Spectroscopy June 2015 Installation of the Dual Polarization ALMA Band 3 Receiver Old 12 m: 4 separate receiver bays ALMA 12 m: receiver cabin (carbon fiber) with ONE flange All previous receivers: Repackaged for use ALMA Band 3 (84-116 GHz) Dual polarization, sideband-separating

4 70 th International Symposium on Molecular Spectroscopy June 2015 Why Study the Helix Nebula ? Helix: one of oldest know planetary nebula (PNe) PNe phase: important in stellar evolution Final stage in life cycle of ~1-8 M  stars Most stars go through this phase Follows the Asymptotic Giant Branch (AGB) During AGB phase, high mass loss occurs  creates molecule-rich circumstellar shell Mass loss continues into PNe phase Central Star: Hot UV-emitting white dwarf Remnant AGB shell flows far from star  becomes highly ionized Ejected into diffuse ISM Timescales of 10,000 yrs. IR image: AGB star What finally becomes of AGB molecular material ?? PNe

5 70 th International Symposium on Molecular Spectroscopy June 2015 e Are PNe providing the diffuse ISM With Molecular Material ????  Study oldest nebula known  HELIX Molecules In Molecules Out ?

6 70 th International Symposium on Molecular Spectroscopy June 2015 Previous Studies of the Helix Detections of Polyatomic Molecules at one position: (-372,0) HCN, HNC, HCO +, H 2 CO, C 2 H, c-C 3 H 2 Work by Bachiller et al. 1997 Then Tenenbaum et al. 2009 using ARO Followed by more global studies at ARO H 2 CO and HCO + detected at 8 NEW positions across Helix (Zack & Ziurys 2013) Molecular gas DENSE and WARM n(H 2 ) ~ 0.3 - 8 x 10 5 cm -3 ; T K ~ 20 – 45 K Full Map of J = 1 → 0 transition of HCO + (Zeigler et al. 2013) HCO + Present at most positions Emission follows optical atomic image

7 70 th International Symposium on Molecular Spectroscopy June 2015 HCO + H 2 CO Zack & Ziurys 2013 Each position: samples different velocity structure Fractional Abundances across nebula f(HCO + ) ~ 0.3 – 7 x 10 -8 f(H 2 CO) ~ 0.3 – 3 x 10 -7 Map of HCO + showed bipolar structure

8 70 th International Symposium on Molecular Spectroscopy June 2015 Christmas 2014: Telescope ready for First Action ??? Helix good test source Velocity structure is so distinct Study HCN: J = 1→0 and CCH: N = 1→0 87 – 88 GHz: Band 3 HCN: quadrupole hyperfine structure 1:5:3 ratio CCH: magnetic hyperfine structure Two components HCO + H 2 CO HCN

9 70 th International Symposium on Molecular Spectroscopy June 2015 Christmas 2014: Telescope ready for First Action ??? Helix good test source Velocity structure is so distinct Study HCN: J = 1→0 and CCH: N = 1→0 87 – 88 GHz: Band 3 HCN: quadrupole hyperfine structure 1:5:3 ratio CCH: magnetic hyperfine structure Two components CCH

10 70 th International Symposium on Molecular Spectroscopy June 2015 Velocity Structure in the Helix Nebula HCN: J = 1→0 CCH: N = 1→0

11 70 th International Symposium on Molecular Spectroscopy June 2015 Current Results for HCN and CCH in the Helix HCN and CCH detected across the Helix Nebula Exhibits same velocity structure as HCO + and H 2 CO Polyatomic molecules: well-mixed and widespread Column densities: N tot (HCN) ~ 0.55 – 2.1 x 10 12 cm -2 N tot (CCH) ~0.5 - 2 x 10 12 cm -2 Fractional abundances: CCH: f ~ 10 -7 ; HCN: f~ 0.7-3 x 10 -7 Comparable to H 2 CO Onto ever more complicated species: c-C 3 H 2 Found at 3 new positions and counting Polyatomic molecules ABUNDANT in oldest PNe! Seeding the diffuse ISM with polyatomic molecules

12 70 th International Symposium on Molecular Spectroscopy June 2015 Debbie Schmidt Nick Woolf Lindsay Zack, PhD Jessica Edwards PhD Thanks to NSF and NASA for funding Staff of ARO Welcome the new 12 m Telescope at Kitt Peak ! PhD


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