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| Miscellaneous :
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Baldovin et al. 2009 ATel 2196:
- Detected by INTEGRAL in the 3-7, 7-11, 11-20 (JEM-X) and
20-40, 40-80 keV (IBIS) mosaics (2009-09-12 03:21:34 to 2009-09-12 05:27:22).
- 3-100 keV (JEM-X/ISGRI) spectrum <=> power-law with Γ~2.0
- 3-20 keV flux (resp. 20-100 keV) = 5.7e-10 erg/cm2/s (4.8e-10 erg/cm2/s)
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Markwardt et al. 2009 ATel 2197:
- RXTE =>barycentred pulse frequency of 244.8337 Hz
- orbital period of 207.4 min.
- Minimum mass of 0.13 Msol for the companion.
- Source is not XTE J1751-305
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Bozzo et al. 2009 ATel 2198:
- Swift => thermonuclear X-ray burst, most likely an He burst
- Spectrum <=> absorbed cut off power law with
NH=0.6 x 1022 cm-2, Ecut~3.3 keV,
Γ~0.2
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Watts et al. 2009 ATel 2199:
- RXTE => burst oscillations @ 245 Hz, during the type
I X-ray burst of IGR J17511-3057 observed on Sept. 14th, 2009.
- Burst oscillation amplitude exceeds 10% rms in the 2-60 keV energy range.
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Nowak et al. 2009 ATel 2215:
- Chandra obs.
- 5" offset wrt Swift pos.=>pile up of Swift rendered the
uncertainty on the source position larger than the 3.5"
- X-ray burst during observation
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Torres et al. 2009 ATel 2216:
- NIR observaiton
- Preliminar Ks=18.0 objetc in Chandra error
- Source is a viable counterpart
for the millisecond pulsar.
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Papitto et al. 2009 ATel 2220:
- XMM observations=> position consistent with Chandra
- Spectrum fitted with a multicolor
disk black body (kTin=0.13 keV) plus a single temperature black body
(kT=0.73keV) and a power law of with Γ=1.71
- Timing analysis reveals the
source is spinning at a frequency of 244.8339512 Hz.
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Riggio et al. 2009 ATel 2221:
- Pulsation is
present in all the RXTE observations of the source.
- Raw pulse fraction is 12%.
- no spin up/spin down trend, but some phase delays fluctuations
- Orbital ephemeris:
- Orbital period: 12487.5126 s,
- Projected semimajor axis: 275.194 lt-ms,
- Time of passage for ascending node: 55088.0320280 MJD,
- Eccentricity e: < 6e-5 (2 sigma c.l.)
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Bozzo et al. 2010 A&A:
- First weeks of Swift monitoring
- Occurrences of X-ray bursts
- Persistent emission cannot be fitted by a single absorbed power law component, but
always requires the addition of a black body with temperature ~1 keV and radius ~3.6-6.3 km
- BB interpreted as arising from the surface of the neutron star (hot spots)
- NH compatible with the Galactic value on the line
of sight
- Spectral analysis of the burst do not reveal any photospheric radius expansion.
- Nature of the bursts likely produced by the ignition
of pure Helium
- => upper limit of ~10.1 kpc for the distance to the source
- Recurrence time of bursts like expected from
nuclear burning of helium
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Papitto et al. 2010 MNRAS:
- XMM and RXTE analysis
- Pulsations at 244.8339512 Hz the outburst, pulse fraction of 14.4%
- Derive an orbital period ~3.5 hours.
- 2 type I X-ray bursts attributed to pure helium environment
- No photospheric radius expansion => d>~ 6.5 kpc
- Source probably belongs to the Galactic bulge
- XMM and XMM+RXTE spectral analysis =>
thermal components due to an accretion disc, and of the neutron star surface,
thermal comptonisation, reflection on the accretion disc (skewed iron line, and
compton hump)
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Altamirano et al. 2010 MNRAS:
- Discovery of burst oscillationsat the spin frequency mainly from RXTE observations
- Fine spectral and temporal analysis of data showing type I burst
- Properties of the burst oscillations similar to those of other
persistent accreting ms pulsar, but oscillations
not detected during the whole duration of the bursts
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Kalamkar et al. 2011 (ApJ):
- Possible discovery of twin kHz QPOs with RXTE
- Behaviour of this source similar to that of Atoll NS-LMXBs
- Source spent its outburst in the extreme Island state
- Frequency difference between the two kHz QPO is consistent with half
the spin frequency of the NS, a
behaviour usually seen in fast rotators.
- Peculiar source which could play an important role in the understanding of kHz QPOs in
NS LMXBs and AMPs.
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Ibragimov et al. 2011 (MNRAS):
- In-depth analysis of the 2009 outburst from Swift and RXTE observations.
- Spectra well fitted with a model of Comptonization (accretion shock, kTe~30 keV, τ~2)
plus a black body (NS hot spot,kT~1 keV)+ presence of a cold disk (~0.2 keV), and
NH~0.9 x1022 cm-2
- Weak reflection component and an iron line
- Pulse profile do not evolve significantly in shape, and show a moderate decrease in pulse
amplitude
- Time lags between the soft and hard pulses increase during the outburst
- Mention in particular that the behavior of the lags could be for example due
to a displacement of the accretion shock relative to the hot spot, other scenario presented
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Paizis et al. 2012 (ApJ):
- 20-ks Chandra grating observation
- Most accurate X-ray position available
- Detection of type-I X-ray burst. Average luminosity (0.5-8 keV) of 1.6e37 erg/s
- X-ray spectrum during (54s-long) burst modeled with 1.6 keV blackbody(on average),
with variations from 2.5 keV at the peak of the burst to 1.3 keV at the tail
- Relative size of the emitting region (5 km) does not change significantly.
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