IGR J18179-1621

Other name = (?)

Type Spin P./ Orb. P. Radio Counterpart Infrared/Optical Counterpart
R.A. (J2000) Dec. (J2000) References R.A. (J2000) Dec. (J2000) References
HMXB 11.82s / 2MASS J18175218-1621316 Li et al. 2012 ATel 3950
Published Papers
Miscellaneous :
Tuerler et al. 2012 ATel 3947:
  • Discovery and detection both by JEM-X and ISGRI onboard INTEGRAL
  • Combined JEM-X and IBIS/ISGRI spectrum => cut-off power-law (Γ~-0.5, Ecut~4.9 keV) + broad Gaussian absorption line at ~20.8 keV
  • If absorption line = cyclotron scattering => source is a high mass X-ray binary pulsar with B~1.7e12 G
Halpern 2012: ATel 3949
  • Swift XRT observation=>strong signal in the periodogram at 11.82s
  • Pulse fraction of 27%.
  • Interpreted as the signature of a HMXB with pulsar
Li et al. 2012: ATel 3950
  • Swift XRT observation=>refined X-ray position (after correction for pile up)
  • Spectra (2 Swift observations) => absorbed power law with NH,1=11.0 x 1022 cm-2 and NH,2=15.1 x 1022cm-2 Γ1=0.4 and Γ2=0.7
  • 3-10 keV fluxes compatible with JEMX detection
  • 2MASS J18175218-1621316 (RA =274.467438 dec=-16.358791) is a Ks=11.4 IR counterpart
Finger et al. 2012: ATel 3961
  • Detection of 11.82s pulsations with Fermi/GBM
  • Pulsations detected at 84.5896 mHz (84.5908 mHz) with rms amplitude 5.9 mCrab (8.5 mCrab) in data of Feb. 20-23 (Feb. 24-27) 2012.
Paizis et al. 2012: ATel 3988
  • Chandra refined position
  • 2MASS has Ks=13.136 and is confirmed as the IR counterpart
Li et al. 2012 (MNRAS) and Bozzo et al.2012 (A&A):
  • Swift and INTEGRAL observations
  • Confirm the detection of a 11.82s pulsation, with a pulse fraction of 22%
  • Presence of an absorption feature at 21.5 keV in addition to an absorbed (NH=12.3 x1022 cm-2) cutoff power law (Γ=0.59, Ecut =9.97 keV)
  • Absorption line, ifattributed to a cyclotron resonant scattering feature, => B~2.4e12 G
  • Source is an accreting pulsar.
Nowak et al. 2012 (ApJ):
  • Chandra and NIR observations
  • NIR observations => source compatible with 2MASS source, with Ks=13.14, Hn=16.0 and Jn> 18
  • No variability in NIR source when comparing to previous (eg UKIDSS) measurements at time of no X-ray emission
  • Strong periodic signal at 11.82s confirming pulsating nature of the source
  • Quasi simultaneous Chandra+Swift spectra => absorbed power law (NH2.2 x 1023 cm-2, Γ=0.4)
  • LMXB nature unlikely, and an HMXB is preferred although the source is unusual in many ways

Last updated 22 Aug. 2012

Jerome Rodriguez