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Title: ASTROCHEMICAL CORRELATIONS IN MOLECULAR CLOUDS

We investigate the spectral correlations between different species used to observe molecular clouds. We use hydrodynamic simulations and a full chemical network to study the abundances of over 150 species in typical Milky Way molecular clouds. We perform synthetic observations in order to produce emission maps of a subset of these tracers. We study the effects of different lines of sight and spatial resolution on the emission distribution and perform a robust quantitative comparison of the species to each other. We use the Spectral Correlation Function (SCF), which quantifies the root mean squared difference between spectra separated by some length scale, to characterize the structure of the simulated cloud in position-position-velocity (PPV) space. We predict the observed SCF for a broad range of observational tracers, and thus identify homologous species. In particular, we show that the pairs C and CO, C{sup +} and CN, and NH{sub 3} and H{sub 2}CS have very similar SCFs. We measure the SCF slope variation as a function of beam size for all species and demonstrate that the beam size has a distinct effect on different species emission. However, for beams of up to 10'', placing the cloud at 1 kpc, the change is not largemore » enough to move the SCF slopes into different regions of parameter space. The results from this study provide observational guidance for choosing the best tracer to probe various cloud length scales.« less
Authors:
;  [1] ;  [2] ;  [3]
  1. Department of Astronomy, University of Massachusetts—Amherst, Amherst, MA (United States)
  2. Department of Physics, University of Alberta, Alberta, CA (Canada)
  3. Department of Physics and Astronomy, University College London, London (United Kingdom)
Publication Date:
OSTI Identifier:
22364275
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 799; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMMONIA; CARBON IONS; CARBON MONOXIDE; CARBON NITRIDES; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; CORRELATION FUNCTIONS; CORRELATIONS; COSMIC GASES; HYDRODYNAMICS; MILKY WAY; MOLECULES; PROBES; SPACE; SPATIAL RESOLUTION; TURBULENCE; VARIATIONS