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| Miscellaneous :
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Kennea et al. 2005 (Atel 500):
- NH~5.2 x 1022 cm-2
- Gamma~2.12
- F0.5-10 keV=8.4 x 10-10
erg/s/cm2
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Juett et al. 2005 (Atel 521):
- Ks=16.2
- Not a obscured HMXB
- Magellan I/PANIC image available here (courtesy A.M. Juett)
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Torres et al. 2005 (Atel 634):
- Confirm that candidate proposed by Juett et al, 2005 (ATel 521), is indeed the NIR counterpart.
- This counterpart has dimmed (not detected at 3-sigma upper limit magnitude of Ks>17.4).
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Del Monte et al. 2008 (Atel 1445):
- Detection of a burst with the super Agile detector onboard AGILE
- The burst detected on 26 March 2008, 23:19:40 UT, and
lasted ~40 s, significant only in the
energy range 17-25 keV.
- For d~8.5 kpc, the 17-25 keV luminosity~ 0.9e38 erg/s=> consistent with an Eddington
limited flux for a neutron star mass.
- Burst is a Type I X-ray burst => IGR J17473-2721 is an X-ray burster
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Altamirano et al. 2008 (Atel 1459):
- XRT observation => X-ray position consistent with the Chandra
- Confirms the association with the detection of a type I burst by Agile.
- XRT spectrum well fitted by an absorbed power law
with Γ=1.68 and NH=3.8e22cm-2.
- Detection of a 100s long X-ray burst, black body of 2.3 keV, no
photospheric radius expansion
- Upper limit to the distance between 3.9 and 5.4 kpc.
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Markwardt et al. 2008 (Atel 1460):
- RXTE monitoring scan => persistent activity on 2008-03-28 and 2008-03-31 at 2-10
keV fluxes of about 13 and 18 mCrab.
- Previous scans consistent with quiescent level with 2 sigma upper limit of
6 mCrab.
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Kuulkers et al. 2008 (Atel 1461):
- INTEGRAL/ISGRI detection during Galactic bulge monitoring.
- 18-40 keV and 40-80 keV fluxes of 41 mCrab and 42 mCrab respectively => hard spectral state.
- Previous observation (2008 March 22): source possibly seen near detection limit :6.5 mCrab (18-40 keV).
- Images and details can be found at
http://isdc.unige.ch/Science/BULGE/ (courtesy Erik Kuulker).
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Baldovin Saavedra et al. 2008 (Atel 1468):
- Source flux has increased by a factor of 3 in 8 days
- Detected by ISGRI up to 250 keV. 20-250 keV flux 2.7 10-9
erg/cm2/s
- 50s long X-ray burst detected, with 0.1-100 keV flux 3.7 10-8
erg/cm2/s, with a BB of kT=2.4 keV
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Altamiraino et al. 2008 (Atel 1651):
- RXTE monitoring, maximum reached unabsorbed flux of ~1.30E-8 ergs
cm-2 s-1 (2-10 keV, with nH=3.8e22cm-2) on June 22nd 2008
- Switch from hard state to soft state and back during outburst
- During the soft state: 6 observations show a kHz QPO at frequency up
to ~900 Hz, reaching up to 8% rms => neutron star atoll sources.
- 16 type-I X-ray bursts, 2 with photospheric radius expansion
=>distance between 4.9-5.7 kpc.
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Zhang et al.
2009 (A&A):
- Swift and RXTE observations of 2 periods of outbursts
- Outburst separated in different sequences. Spectral analysis of these.
- State transition hard state->soft state-> hard state showing an hysteresis
- Discussion of the origin of state evolution
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Chen et al.
2010 (A&A):
- RXTE analysis of Type I X-ray bursts from 2 outbursts
- 18 bursts, 3 of which show photospheric radius expansion
=> distance 6.4 kpc (15% error).
- Duration of bursts correlated L/LEdd
- End of the most recent
outburst: profile of the bbody radius anticorrelated with the bbody
temperature
- Discussion in the context of type I bursts in LXMB and Atoll sources in general
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Chenevez et al.
2011 (MNRAS):
- RXTE, Swift, INTEGRAL, Agile observations => total of 57 thermonuclear bursts during 2008 ouburst
- Study of spectral and temporal properties of all bursts, and study the bursting behaviour and burst properties
Burst rate first increases with the accretion rate until it stops. It resumes at a much lower
accretion rate =>Hysteresis whose origin is discussed
- Occurrence of a (missed) super burst as the origin of the quenching of bursting activity
- Some bursts identified as photospheric radius expansion bursts=> distance to the source of 5.5±0.8 kpc
- 7 phases of burst behaviour<=> 4 burst regimes:
Mixed H/He flashes, pure He flashes (with stable H burning), rich He flashes at low dot(m)
and no burst ie stable H and He burning.
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Chen et al. 2011 (A&A):
- RXTE, Swift, INTEGRAL, observations
- Study relation between duration of types I X-ray bursts and source flux
=>
confirm the correlation seen in other sources
=>Slope of the correlation differs between the increasing and decaying part of outburst
- Cut-off energy of X-ray spectra decreases from quiescence to and through the hard state
=> cooling of the coronal electrons by soft photons coming either from the disc or the NS surface
- Corona sits on top of the disc rather than on the NS surface
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