IGR J17191-2821

Other name = (?)

Type NS Spin Radio Counterpart Infrared/Optical Counterpart
R.A. (J2000) Dec. (J2000) References R.A. (J2000) Dec. (J2000) References
Burster, NS primary
LMXB, Atoll
294 Hz
2 possible object within Swift error circle
(RA,DEC) = (259.811453,-28.297926)
(RA,DEC) = (259.812253 -28.297579) +-0.4" for each
Klein-Wolt et al. 2007ATel 1070
Published Papers
Miscellaneous :

Tuerler et al. 2007ATel 1021:
  • 20-40 keV flux of ~9mCrab, marginal det. in 40-80 keV (5.8 mCrab)
  • Mention 2 nearby sources: 1RXS J171909.4-282041 (at 1.4') and IRAS 17159-2819 (@ 1.6') and indicate presence of the unidentified EGRET source 3EG J1717-2737 located at RA=17h 17m 12s, dec=-27deg 37' 48" (+-0.64 deg @95% confidence).
Swank et al. 2007ATel 1022:
  • RXTE detection of source with position coincident
  • 2-10 keV flux of 10 mCrab.
  • Nothing detected with < 0.5 mCrab in following obs
  • Source not detected the following day, and no flares brighter than 2 mCrab seen in a reanalysis of all scans from this region since 1999, Feb 5.
  • Maximum duration of 1.7d of its activity and its hard spectrum.
  • IGR J17191-2821 is a binary with a compact object and a high mass companion.
  • Low-mass companion cannot be excluded, but very short outburst and an unusually hard spectrum then.
  • A stellar flare from a near-by star or an outburst from a magnetar cannot be ruled out either.
Klein-Wolt et al. 2007ATel 1025:
  • No source seen with Swift in INTEGRAL error circle with an upper limit of 0.0021 cnts/s.
  • Translates into an 2-10 keV unabsorbed flux of 8.7*10E-14 erg/s/cm^2 or 0.004 mCrab (Gamma=1.8 and Nh=3.4e21 cm-2)
  • In 1 pointing detection of source at ~3.5' from the INTEGRAL position.
  • The flux is 3.6*10E-13 erg/s/cm^2 (unasorbed) or 0.02 mCrab (same Nh and photon index as above)
  • Source not visible any more in the following pointing.
  • Although the formal INTEGRAL error circle on the position of IGR J17191-2821 indicate that the sources are unrelated, still a small possibility that both sources are one and the same
  • Over the span of 5 days (from March 3 to March 8) IGR J17191-2821 has decreased by a factor 500 or more.
Klein-Wolt et al. 2007ATel 1065:
  • Swift XRT spectrum absorbed powerlaw => NH=5.30 x 1021 cm-2, Γ = 1.75, ~1.2 x 10-9 erg/sec/cm2 (absorbed 2-10 keV flux)
  • Type-I X-ray burst that lasted for about 50 seconds and during which the Swift count rate increased by a factor ~3
  • Burst spectrum fitted with a black body of temperature 0.99 +/- 0.08 keV.
  • Upper limit for the distance of 23 kpc (likely to be closer)
  • Type I burst => NS probably, in a low mass system.
Markwardt et al. 2007ATel 1068:
  • RXTE/PCA detection of an X-ray burst and high frequency oscillations during the burst.
  • The oscillation frequency drifted from about 292 Hz to 294 Hz.
  • Neutron star spin frequency is probably near the maximum oscillation frequency, or 294 Hz.
  • Refine a new distance upper limit of ~11 kpc.
Klein-Wolt et al. 2007ATel 1070:
  • Refinement of the X-ray position
  • V, I and H-band images of the field of IGR J17191-2821 using the SMARTS 1.3m telescope and ANDICAM instrument on May 4.295 UT.
  • Two sources at (RA,DEC) = (259.811453,-28.297926) and (259.812253 -28.297579) +- 0.4", in all three bands.
  • Those sources were previsously indetected in USNO B1.0 and 2MASS catalogues.
Klein-Wolt et al.: 2007ATel 1075:
  • kHz QPO in the range between 700 and 900 Hz in RXTE observations
  • Detection of an additional kHz QPO at a frequency of ~1030 Hz on several occasions.
  • Latter with the upper kHz QPO and the one at lower frequencies with the lower kHz QPO. The frequency separation is about 330 Hz and is consistent within 3 sigma with the spin frequency
  • Behaves during its outburst as a typical neutron star atoll sources in outburst.
Chakrabarti et al. 2007ATel 1096:
  • Chandra obs do not detect any source within 30" from the best position
  • With Γ=1.71 and NH=5.7 x1021 cm-2 => 2-10 keV source flux <6.9 x10-14 erg/cm2/s (<3.2E-3 mCrab) <=> 0.3-10 keV luminosity <1.2 x 1033 ergs/s(11 kpc upper limit)
Altamirano et al. 2010 (MNRAS):
  • X-ray spectral and temporal analysis during outburst (Swift and RXTE)
  • 5 type I X-ray bursts => similar profile, radius and temp. 2 keV < kTmax <3 keV
  • High frequency (605-1185 Hz) QPO => constant Δν when a pair is detected
  • Precursor to the main outburst
  • Spectral transition from soft Banana to hard/extreme island, and back to the soft state => Source is an atoll
  • Nearly coherent burst oscillations at 291-295 Hz => spin of NS ~ 294 Hz
Gangopadhyay et al. 2011 (New Astr.):
  • Estimate mass and compactness from differences between kHz QPOs
  • M=0.843 Msun, and R=6.762 km.

Last updated 16 Feb 2011

Jerome Rodriguez