IGR J17511-3057

Other name =

Type Orb. puls./spin puls. Radio Counterpart Infrared/Optical Counterpart
R.A. (J2000) Dec. (J2000) References R.A. (J2000) Dec. (J2000) References
LMXB/ms X-ray pulsar
X-ray Burster
208.12521min / 244.8339512 Hz 17h 51 08.64 -30o 57' 40.70" Torres et al. 2009 ATel 2216
Published Papers
Miscellaneous :

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)
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
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
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.
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
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.
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.
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.)
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
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)
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
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.
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
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.

Last updated 04 July 2012

Jerome Rodriguez