THE Arizona RADIO OBSERVATORY CO MAPPING SURVEY of GALACTIC MOLECULAR CLOUDS. V. the SH2-235 CLOUD in CO J = 2 - 1, 13CO J >= 2 - 1, and CO J = 3 - 2

John H. Bieging, Saahil Patel, William L. Peters, L. Viktor Toth, G. Marton, Sarolta Zahorecz

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

We present the results of a program to map the Sh2-235 molecular cloud complex in the CO and 13CO J = 2 - 1 transitions using the Heinrich Hertz Submillimeter Telescope. The map resolution is 38″ (FWHM), with an rms noise of 0.12 K brightness temperature, for a velocity resolution of 0.34 km s-1. With the same telescope, we also mapped the CO J = 3 - 2 line at a frequency of 345 GHz, using a 64 beam focal plane array of heterodyne mixers, achieving a typical rms noise of 0.5 K brightness temperature with a velocity resolution of 0.23 km s-1. The three spectral line data cubes are available for download. Much of the cloud appears to be slightly sub-thermally excited in the J = 3 level, except for in the vicinity of the warmest and highest column density areas, which are currently forming stars. Using the CO and 13CO J = 2 - 1 lines, we employ an LTE model to derive the gas column density over the entire mapped region. Examining a 125 pc2 region centered on the most active star formation in the vicinity of Sh2-235, we find that the young stellar object surface density scales as approximately the 1.6-power of the gas column density. The area distribution function of the gas is a steeply declining exponential function of gas column density. Comparison of the morphology of ionized and molecular gas suggests that the cloud is being substantially disrupted by expansion of the H ii regions, which may be triggering current star formation.

Original languageEnglish (US)
Article number13
JournalAstrophysical Journal, Supplement Series
Volume226
Issue number1
DOIs
StatePublished - Sep 2016

Keywords

  • ISM: clouds
  • ISM: individual objects (Sh2-235)
  • ISM: kinematics and dynamics
  • ISM: molecules Supporting material: FITS files

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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