IGR J16479-4514

Other name =

Type Spectral Type / Orb. period
Super Orb P.
Radio Counterpart Infrared/Optical Counterpart
R.A. (J2000) Dec. (J2000) References R.A. (J2000) Dec. (J2000) References
HXMB/ candidate SFXT O8.5 I /3.32 d
16h 48m 06.8 -45° 12' 08.0" Kennea et al. 2005Atel 599
Miscellaneous :

Kennea et al. 2005 (Atel 599):
  • NH=6.4 ± 0.9 x 1022 cm-2
  • Gamma =1.09 ± 0.25
  • flaring activity
  • Mv=20.4 ± 0.4
Sguera et al. 2005 :
  • Fast transient
  • Recurrent outburst
  • Flares lasting 30 min
  • 20-30 keV peak flux of 850 mCrabs on one occasion
  • Possible type I X-ray burst => LMXB
Sguera et al. 2006:
    20-60 keV ~120 mCrab
Walter et al. 2006:
  • some soft excess and marginal K-alpha line (EW < 280 eV)
  • NH = 7.7(+-1.7)x1022 at/cm2
  • IR counterpart (1.3 arcsec away) has a K-band magnitude of 9.8
  • unabsorbed flux (2-100 keV) is 1.8x10-10 ergs/cm2/s
Chaty et al. 2008:
  • Near infrared observations
  • 2 candidates, candidate suggested by Walter is favoured.
  • J=13.06, H=10.92, Ks=9.79
  • Very red Near IR spectrum with absorption and emission lines
  • The H Brackett serie, HeI HeII and FeII in emission in NIR spectra
  • NIR spectra typical of sg O/B
Rahoui et al. 2008:
  • Medium infrared observations
  • SED fitting => AV=18.5, Tstar=32800 K => O8.5I
  • No need for additional component in SED fitting
  • d=4.9 kpc
Romano et al. 2008 ATel 1435:
  • New outburst with Swift/BAT, consisted of two flares, the second stronger than the first.
  • BAT spectra are powerlaw-like (1st flare) and exponentially cut powerlaw-like (2nd flare)
  • XRT lightcurve composed of several flares,
Sguera et al. 2008:
  • Study of 19 X-ray flares, 10 newly discovered.
  • All flares are well fitted (in the ISGRI band) with either a power law (Gamma=2.2-3) or a bremsstrahlung (kT=21-46 keV).
  • Joint XRT/JEM-X/ISGRI spectrum =>absorbed power law with NH=16x1022cm-2 and Γ=2.5, or absorbed bremsstrahlung with NH=9x1022 and kT=19 keV.
  • Spectral analysis of this quiescent state ISGRI+Swift/XRT spectrum =>absorbed powerlaw or bremstrahlung fit the data equally well with Γ=2.2 or kT=20 keV, with NH=9x1022 cm-2. Assuming a distance of 4.9 kpc they deduce an average 20-60 keV luminosity of 5e34 erg/s.
  • IGR J16479-4514 a possible transition object between other SFXTs and classical SGXBs.
Sidoli et al. 2008:
  • Spectral analysis of the "out-of outburst" Swift data
  • Absorbed pl or bbody fits the data well
  • Γ= 1.6 and NH=7.7x1022cm-2 or kT=1.6 keV and NH=4.5x1022cm-2
  • No variations of NH with outburst value
Romano et al. 2008:
  • 0.2-150 keV spectral analysis of 3 particular intervals during the rise of this source's outburst
  • Spectra well represented with standard models for pulsars X-ray binaries
  • No evidence for variability of the absorption.
  • Compact object in this source is probably a pulsar.
Nespoli et al. 2008:
  • Infrared spectroscopy
  • O9.5 Iab suggested
  • Distance 2.8 (-1.7 +4.9)kpc
  • Local absorption comes from material concentrated around the compact object
Bozzo et al. 2008: MNRAS
  • Long XMM observation triggered just after a bright flare observed with Swift
  • Observation is divided in two parts, one having a count rate higher than the other by a factor of ~50 => probably the tail of the bright burst
  • X-ray spectroscopic analysis =>faint phase is probably due to obscuration of the source of X-rays
  • Favour an X-ray eclipse as the origin
  • Presence of an extended (tens of arcsec) dust scattering halo.
Romano et al. 2009 ATel 1920:
  • Detection of a new outburst with Swift/BAT on January 29 2009 at 06:33:07 UT.
  • All spectral parameters consistent with those of previous outburst seen 315 days before
La Parola et al. 2009 ATel 1929:
  • New bright flare with Swift=> part of the same outburst that triggered Swift/BAT on January 29
  • Swift/XRT light curve obtained from the monitoting of the source shows a large variability, with the source being always detected =>still active since January 29.
  • Bright flares spaced by a few days are part of the same outburst : this could be the case also in other SFXTs.
Jain et al. 2009:
  • Strong modulation of the 18-50 keV BAT light curve at 3.32 day => orbital period of the system
  • Period less evident in the ASM data, but still significant once the light curve is folded
  • Presence of a 0.6d eclipsing phase in the light curves
  • Eclipse is seen at the same phase with both Swift and RXTE
Bozzo et al. 2009:
  • Swift observations during outburst in 2009, january and comparison to previous ones.
  • Outbursts precede the eclipse
  • Onset of the 2005, 2008 and 2009 outbursts (seen with Swift/BAT) occur respectively at orbital phases 0.36, 0.3654 and 0.36 => interpret this as an evidence that the outburst, although rare, are connected to the orbital phase
Romano et al. 2009:
  • Results of Swift monitoring of the source
  • Duty cycle 17%
  • Confirm detection P=3.32 d with BAT
  • Complete spectral analysis => spectra well fitted with either an absorbed power law or an absorbed black body
Ducci et al. 2010:
  • Applcation to clumpy wind model=> parameters of the wind slightly different from that of other systems.
  • Study possible other mechanism of flaring activity
  • X-ray photoionisation can lead to formation of a transient accretion disc in this source (and other short orbital period ones).
Ratti et al. 2010:
  • Chandra + optical observation of the counterpart
  • NIR colour indicate a late type red giant or a supergiant earlier than O9 => counterpart peculiar in the NIR region
Romano et al. 2011:
  • 2 years of Swift monitoring
  • duty cycle of inactivity ~ 19%
  • X-ray spectroscopy in different luminosity phases of activity
Wang & Chang 2012 (A&A):
  • Mention of a 2.14s period (refering to http://hera.ph1.uni-koeln.de/~heintzma/Integral/SFXT.htm which worngly refer to Sguera et al.), but no evidence for such a pulse has ever been found
  • Study retrograde wind accretion scenario
  • => spin and orbital period => R corrotation ~ 9.9e9 cm and source is a retrograde accretor
Sidoli et al. 2013 (MNRAS):
  • 80% of the orbit followed with Suzaku
  • Variability of more than two orders of magnitude, with the begining of the observation made during the eclipse by the Sg companion
  • No evidence for variability of the absorption column density (@ ~ 1023 cm-2)
  • Wind density estimated to ρ~ 7x 10-14 g.cm-3
  • Mechanism is to be invoked to reduce the mass accretion rate to be consistent with the luminosity observed
Corbet et al. 2013 ATel 5126 (see also ApJ paper):
  • SuperOrbital modulation found at a period 11.880 days in Swift/BAT data
  • Light curve folded on this period <=> relatively sharp rise from minimum to maximum followed by a plateau.
  • Time of minimum flux is ~ MJD 55993 with Fmax occurring approximately 0.25 in phase after this.
  • A=(Fmax - Fmin)/(Fmean ~ 130%
  • Ratio Psuperorb/Porb~ 3.6 similar to other wind accretion HXMB with superorbital periods
Drave et al. 2013 ATel 5131:
  • Confirmation of SuperOrbital modulation with INTEGRAL at 11.891 d
  • Same profile for the folded light curve as that seen with Swift. A=160%

Last updated 8 Nov. 2013

Jerome Rodriguez