Molecules in Radio Astronomy

General Information and Introductions

• Molecular Rotational Spectra: Excellent overview of molecular spectroscopy by Yancy Shirley.
• Molecular Column Density Calculation: Detailed description of molecular rotational spectroscopy and its relationship to molecular column density calculation. Written both for students and seasoned observers.
• Molecular Emission: A molecular emission primer by Al Wootten.
• Planetary Astrophysics and Star Formation: Introductory presentation describing the study of planets, comets, and star formation from a millimeter-astronomy perspective. Written for summer students, but also appropriate for novice millimeter astronomers.

Modelling

• Large Velocity Gradient Approximation:
  • A Generalization of the Sobolev Method for Radiation Transport with Local and Nonlocal Line Overlap (Pavlakis & Kylafis; ApJ 467, 292 (1996))
  • HCN Hyperfine Anomalies in Dark Clouds (Gonzalez-Alfonso and Cernicharo; A&A, 279, 506 (1993)). Description of LVG code which includes line (hyperfine) overlap.
• Monte Carlo Method:
  • An Accelerated Monte Carlo Method to Solve Two-Dimensional Radiative Transfer and Molecular Excitation (Hogerheijde & van der Tak; A&A 362, 697 (2000)
  • RATRAN radiative transfer code description

Molecular Excitation

• Symmetric Tops:
  • CH3CN (Methyl Cyanide)
    • Ammonia and Methyl Cyanide in Hot Cores (Olmi, Cesaroni, & Walmsley; A&A 276, 489 (1993))
    • The Methyl Cyanide Hot and Warm Cores in Orion - Statistical Equilibrium Excitation Models of a Symmetric-Top Molecule (Loren & Mundy; ApJ 286, 232 (1984))
  • H2CO (Formaldehyde; which is not really a symmetric top but only slightly asymmetric)
    • Formaldehyde as a Probe of Physical Conditions in Dense Molecular Clouds (Mangum & Wootten, ApJS 89, 123 (1993))

• Ions:
  • N2H+ (Diazenylium)
    • The Excitation of N2H+ in Interstellar Molecular Clouds. I. Models (Daniel, Cernicharo, and Dubernet; ApJ 648, 461 (2006))
      • Excellent overview of N2H+ excitation including hyperfine overlap.
      • Use for reference to method for dealing with line overlap. & Collisional Excitation Rate Coefficients of N2H+ by He (Daniel, Dubernet, Meuwly, and Cernicharo; MNRAS, 363, 1083 (2005))