Studies of Star Formation in the Nearby Universe

Atacama Large Millimeter/submillimeter Array

Karl G. Jansky Very Large ArrayRobert C. Byrd Green Bank Telescope

Very Long Baseline Array

Studies of Star Formation in the Nearby Universe

Jeff MangumNRAO

ALMA

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ALMAExtragalactic Star Formation

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• 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)

ALMAExtragalactic Environmental Analysis

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• 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 (H2CO, etc.)

ALMAExtragalactic Heating Processes

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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 + HEbarrier = 200 K

ALMAExtragalactic Star Formation

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• H2CO K-doublet excitation used as density monitor

• Transition ratios used as density and temperature probe

Mangum etal (2008, 2013)

ALMAExtragalactic Star Formation

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ALMAExtragalactic Star Formation: Spatial Density

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H2CO K-doublet excitation used as density monitor

Mangum etal (2008, 2013)

ALMAExtragalactic Star Formation: Kinetic Temperature

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H2CO excitation used as kinetic temperature monitor

Mangum & Wootten (1993)

ALMAStar Formation in the Nearby Universe at Band 2

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• Trace extragalactic star formation heating processes (HCN/HNC)• Measure spatial density and kinetic temperature (H2CO

K-doublets)• Trace UV penetration into dense environments (HCO+,

DCO+)• Identify shock environments (SiO)

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