IGR J17498-2921

Other name = (?)

Type Porb./ Fspin Radio Counterpart Infrared/Optical Counterpart
R.A. (J2000) Dec. (J2000) References R.A. (J2000) Dec. (J2000) References
LMXB, Burster
ms X-ray pulsar
3.8432275 hr / 400.9901872872 Hz
Published Papers
Miscellaneous :

Gibaud et al. 2011ATel 3551:
  • INTEGRAL discovery. IBIS spectrum => power law Γ=1.9
Bozzo et al. 2011ATel 3555:
  • Swift/XRT observations => pile up corrected spectrum absorbed power law, NH=3 x 1022 cm-2, Γ=1.9
Papitto et al. 2011ATel 3556:
  • RXTE Observation => detection of a 401 Hz oscillation => source possibly a ms accreting pulsar
Jonker et al. 2011ATel 3559:
  • Chandra observation => detection of quiescent counterpart at Fx=2.5e 14 erg/cm2/s
Ferrigno et al. 2011ATel 3560:
  • Detection of a type I X-ray burst from INTEGRAL/JEM-X
  • Burst is 15s long and has a decay time of 6s
  • Burst is well fitted by black body kT~1.4 keV and R~19 km (at 10 kpc)
Markwardt et al. 2011ATel 3561:
  • Two candidates orbital solutions at 3.8432 hr and 4.0834 hr from an RXTE observation
Greiss et al. 2011ATel 3562:
  • NIR source has J = 17.45, H = 15.73 and Ks = 15.10
  • Extinction lower than that obtained from fits to the X-ray spectra
  • De-reddened magnitudes are consistent with a late K or early M type star => source is an LMXB
  • If NIR and X-ray sources are associated then system much closer than Galactic bulge
Papitto et al. 2011ATel 3563:
  • Several RXTE obs => orbital solution is 3.84281hr
Linares et al. 2011ATel 3568:
  • RXTE obs => Type I X-ray burst + burst oscillations
  • Burst:
    • total duration (PCA) 30s
    • Absorbed black body model with cooling tail (kT from 2.6 keV to 1.4 keV)
    • Moderate photospheric expansion during burst rise and peaks
    • Burst oscillations at ~401 Hz detected during 2-3 s in the tail after PRE episode
  • Distance estimated to 7.6kpc
  • Total radiated energy = 3.2e39 erg
Markwardt & Strohmayer 2011ATel 3601:
  • Refined orbital solution
  • Coherent pulsation at 400.990187287 Hz (non corrected for the RXTE orbit and without clock correction applied)
  • Orbital period 13865.615 s
  • Projected semi major axis 0.365108 lt-sec
  • Masses between 0.17 and 0.22 Solar masses for the companion depending of the NS mass
Russell et al. 2011ATel 3622:
  • Optical observations with Faulkes telescope
  • 4σ source detected at position consistent with X-ray and quiescent IR counterparts=> likely optical counterpart
  • i'~ 22.5
van der Berg et al. 2011ATel 3634:
  • Optical and NIR observations
  • Optical source consistent with Chandra position and associated to Faulkes counterpart
  • Estimate of i' consistent with no variation between quiescence and outburst => source probably not counterpart to the IGR, probable chance alignment
Torres et al. 2011ATel 3638:
  • NIR and Chandra observations
  • IR counterpart has H~16.0 consistent with pre-outburst value=> not related to X-ray source
  • Chandra spectra => power law with Γ=1.75 and NH=2.87x1022
Chakraborty et al. 2011ATel 3643:
  • Detection and analysis of 10 X-ray bursts
  • One shows photospheric radius expansion
  • burst oscillations detected in the tail of the PRE X-ray flare
Linares et al. 2011 ATel 3661 (see also Chakraborty et al. 2012 for detailed analysis and discussion):
  • Swift monitoring
  • Two X-ray burst were detected two X-ray bursts on Aug. 18 and 28 (2011)
  • The source count rate remained ~constant until Aug. 24
  • The count rate then started to decrease slowly until Sep. 18
  • In the last two observations of this period (Sep. 17 and 18) the source spectrum was soft => fitted with an absorbed blackbody with kT~ 0.6 keV Nh fixed at 3e22 cm-2 (a very soft absorbed power law also fits the data well)
  • Not detected during five Swift-XRT observations on Sep. 19, 20, 22, 24 and 26 => has returned to quiescence
Papitto et al. 2011 (A&A):
  • Analysis of RXTE and Swift observations
  • Coherent pulsation at 400.99018734 Hz,
  • Analysis the modulations of pulsation=> orbital period of ~3.84 hr
  • Mass of the donor between 0.17 Msun (lower limit) and 0.48 Msun (upper limit)
  • Spectra well modeled with absorbed power law with Γ comprised between 1.7 and 2
  • Close to quiescence Γ softer.
Falanga et al. 2012 (A&A):
  • Analysis of simultaneous Swoft, RXTE and INTEGRAL observations
  • Broad band 0.6-300 keV spectrum well described by thermal Comptonisation with kTe~50 keV, kTbb~1 keV and τ=1 in a slab geometry with an area ~ 9 km
  • No spetral variations during outburst => X-ray emission originate above the surface in hot slab (heated NS surface or accretion shock)
  • 2.5ms pulsation detected up to 65 keV
  • Pulsed fraction is energy independent and is found around 6-7%
  • Analysis of burst => hydrogen poor material at ignition => material hydorgen deficient or CNO metallicity up to twice the solar values
  • Burst recurrence time smaller than predicted by He-ignition models

Last updated 22 Aug. 2012

Jerome Rodriguez