Shell-shocked: The interstellar medium near Cygnus X-1

P. H. Sell, S. Heinz, E. Richards, T. J. Maccarone, D. M. Russell, E. Gallo, R. Fender, S. Markoff, M. Nowak

Research output: Contribution to journalArticlepeer-review


We conduct a detailed case study of the interstellar shell near the high-mass X-ray binary, Cygnus X-1. We present new WIYN optical spectroscopic and Chandra X-ray observations of this region, which we compare with detailed MAPPINGS III shock models, to investigate the outflow powering the shell. Our analysis places improved, physically motivated constraints on the nature of the shock wave and the interstellar medium (ISM) it is plowing through. We find that the shock is travelling at less than a few hundred km s-1 through a low-density ISM (<5 cm-3). We calculate a robust, 3s upper limit to the total, time-averaged power needed to drive the shock wave and inflate the bubble, <2 × 1038 erg s-1. We then review possible origins of the shock wave. We find that a supernova origin to the shock wave is unlikely and that the black hole jet and/or O-star wind can both be central drivers of the shock wave. We conclude that the source of the Cygnus X-1 shock wave is far from solved.

Original languageEnglish (US)
Pages (from-to)3579-3592
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - Feb 1 2015


  • ISM: jets and outflows
  • Shock waves
  • X-rays: binaries
  • X-rays: individual: cygnus X-1

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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