The DDO IVC distance project: Survey description and the distance to G139.6+47.6

Christopher R. Burns, Christopher Tycner, Megan McClure, Kris Blindert, Rosemary McNaughton, Michael D. Gladders, Allen Attard

Research output: Contribution to journalReview articlepeer-review


We present a detailed analysis of the distance determination for one intermediate-velocity cloud (IVC, G139.6+47.6) from the ongoing DDO IVC Distance Project. Stars along the line of sight to G139.6+47.6 are examined for the presence of sodium absorption attributable to the cloud, and the distance bracket is established by astrometric and spectroscopic parallax measurements of demonstrated foreground and background stars. We detail our strategy regarding target selection, observational setup, and analysis of the data, including a discussion of wavelength calibration and sky subtraction uncertainties. We find a distance estimate of 129 ± 10 pc for the lower limit and 257-33+211 for the upper limit, Given the high number of stars showing absorption due to this IVC, we also discuss the small-scale covering factor of the cloud and the likely significance of nondetections for subsequent observations of this and other similar IVCs. Distance measurements of the remaining targets in the DDO IVC project will be detailed in a companion paper.

Original languageEnglish
Pages (from-to)2584-2589
Number of pages6
JournalAstronomical Journal
Issue number5 1769
StatePublished - May 2003


  • ISM: clouds
  • ISM: individual (G139.6+47.6)
  • ISM: structure
  • Stars: distances
  • Techniques: spectroscopic


Dive into the research topics of 'The DDO IVC distance project: Survey description and the distance to G139.6+47.6'. Together they form a unique fingerprint.

Cite this