Spectral study of GX 339-4 with TCAF using Swift and NuSTAR observation

Santanu Mondal, Sandip K. Chakrabarti, Dipak Debnath

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


We fit spectra of galactic transient source GX 339-4 during its 2013 outburst using Two Component Advective Flow (TCAF) solution. For the first time, we are fitting combined NuSTAR and Swift observation with TCAF. We use TCAF to fit 0.8–9.0 keV Swift and 4–79 keV NuSTAR spectra along with the LAOR model. To fit the data we use disk accretion rate, halo accretion rate, size of the Compton cloud and the density jump of advective flows at this cloud boundary as model parameters. From TCAF fitted flow parameters, and energy spectral index we conclude that the source was in the hard state throughout this particular outburst. The present analysis also gives some idea about the broadening of Fe Kα with the accretion rate. Since TCAF does not include Fe line yet, we make use of the ‘LAOR model’ as a phenomenological model and find an estimate of the Kerr parameter to be ∼ 0.99 for this candidate.

Original languageEnglish
Article number309
JournalAstrophysics and Space Science
Issue number9
StatePublished - 1 Sep 2016
Externally publishedYes


  • Accretion disks
  • Black holes
  • Radiation hydrodynamics
  • Spectrum
  • Stars: individual (GX 339-4)
  • X-rays: binaries

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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