| 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.
- 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.
- 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
- 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.
- 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.
- 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.
- 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.:
- 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.
- 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.