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Atacama Large Millimeter/submillimeter Array Karl G. Jansky Very Large Array Robert C. Byrd Green Bank Telescope Very Long Baseline Array Studies of Star.

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Presentation on theme: "Atacama Large Millimeter/submillimeter Array Karl G. Jansky Very Large Array Robert C. Byrd Green Bank Telescope Very Long Baseline Array Studies of Star."— Presentation transcript:

1 Atacama Large Millimeter/submillimeter Array Karl G. Jansky Very Large Array Robert C. Byrd Green Bank Telescope Very Long Baseline Array Studies of Star Formation in the Nearby Universe Jeff Mangum NRAO

2 ALMA 2

3 Extragalactic Star Formation 3 Multi-transition analysis of molecular excitation within high spatial density (n(H2) > 10^5 cm^-3) and high kinetic temperature (Tk > 100 K) environments Atomic fine structure transition measurements of the warm neutral and ionized gas Herschel SPIRE apodized FTS spectrum of M82 from Panuzzo etal. (2010). Spatial resolution is 43.4 arcsec. Filled circles show SPIRE fluxes measured within the same beam. Herschel SPIRE spectrum of Arp220 (Rangwala etal. 2012)

4 ALMA Extragalactic Environmental Analysis 4 Silicon-bearing species which track shock environments (SiO) Ions which are chemical tracers of UV emission (HCO +, DCO + ) Isomer species which can be used as diagnostics of heating mechanisms within star formation regions (HCN/HNC, etc.) More complex symmetric and asymmetric top molecules which can be used as targeted density and temperature probes of dense gas (H 2 CO, etc.)

5 ALMA Extragalactic Heating Processes 5

6 ALMA Extragalactic Heating Processes 6 PDR model predictions of the HCN and HNC abundances as a function of column density for varying amounts of cosmic ray (zeta) and mechanical (gamma_mech) heating from Meijerink etal. (2010). HCN/HNC ratio a sensitive monitor of heating processes HNC + H  HCN + H E barrier = 200 K

7 ALMA Extragalactic Star Formation 7 H 2 CO K-doublet excitation used as density monitor Transition ratios used as density and temperature probe Mangum etal (2008, 2013)

8 ALMA Extragalactic Star Formation 8

9 ALMA Extragalactic Star Formation: Spatial Density 9 H 2 CO K-doublet excitation used as density monitor Mangum etal (2008, 2013)

10 ALMA Extragalactic Star Formation: Kinetic Temperature 10 H 2 CO excitation used as kinetic temperature monitor Mangum & Wootten (1993)

11 ALMA Star Formation in the Nearby Universe at Band 2 11 Trace extragalactic star formation heating processes (HCN/HNC) Measure spatial density and kinetic temperature (H 2 CO K-doublets) Trace UV penetration into dense environments (HCO +, DCO + ) Identify shock environments (SiO)

12 12 The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. www.nrao.edu science.nrao.edu


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