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| Miscellaneous :
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Markwardt et al 2004 Atel 353, Atel 360 :
- NH~7 x 1021 cm-2
- Gamma~1.7
- pulsation at 598.88 Hz with 6% amplitude
- Orbital period 147.412 min
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| Remillard 2004 Atel 357: possible recurrence time of 3 years |
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| Fox and Kulkarni 2004, Atel 354: R~17.4 in outburst |
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| Roelofs et al. 2004 Atel 356: (Optical) emission lines features near the HeII line (4686 A)
and near the Halpha line (6563 A) |
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Steeghs et al. 2004 ATel 363: - Infrared counterpart with
J=16.8 ± 0.1, H=16.8 ± 0.3, K=16.1 ± 0.2, fading rapidly, Optical counterpart R=18.3 ± 0.4 (5 days after first
detection reported in Atel 354).
- Infrared images available
here
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| Filippenko et al. 2004 Atel 366: Optical
spectroscopy with the KECK telescope. Broad emission lines (FWHM = 1200 km/s): H alpha (EW=0.96 nm),
H-beta (EW = 0.54 nm), He I 667.8nm (EW = 0.1 nm). Weak and narrow (FWHM = 300 km/s) feature identified as
He II 468.6 nm (EW=0.06nm) |
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| Nowak et al. 2004, Atel 369: Improved X-ray position, association with Optical reinforced,
NH~2.8 +/- 0.4 x 1021 cm-2, and Gamma = 1.9 +/-0.1, possible Iron line |
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| Shaw et al. 2005, A&A: Comptonised spectrum kTe~25 keV, and Tau~3.5 |
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| Bikmaev et al. 2005, Atel 395: Optical monitoring, exponential decay e-folding time~5.7 days. R light curve available
here |
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Galloway et al. 2005, ApJL: - Pulse in 6-9 keV lags pulse at lower energy by up to 85 microsecond
- Pulse RMS decreses with energy
- Distance (at least but not much larger than) 4 kpc, although caution is expressed
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Jonker et al.
2005, MNRAS : - Source detected in quiescence by Rosat in 1992
- 3 Chandra observations similar to the Rosat one -> in quiescence more than 30 days after discovery
- Spectra = simple black body with (high) temperature ~0.3 keV or BB+ powerlaw with kT=0.28 keV
- Variability on X-ray flux even in quiescence, similar to what reported for other NS XRT
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Paizis et al. 2005: : - Spectra can be fitted with a two component model involving a thermal component and a
power law.
- Along the outburst the power law component show no particular trend
- Thermal component (interpreted as a hot spot on the surface of the pulsar) becomes weaker
until it is not detected any more.
- Simultaneous Chandra/RXTE observations: the 1~keV hot spot has
disappeared while a 0.4 keV thermal component shows up in the spectra -> manifestation of the accretion disc.
- possible presence of the 6.4 keV iron line with an
excess around 6.8 keV and an absorption feature around 7.1 keV -> may originate in an expanding hot corona, with high outflow velocities
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Falanga et al. 2005: : - RXTE & INTEGRAL spectra indicative of thermal Comptonisation.
- Spectral parameters roughly constant over the outburst
- Pulse detected up to 150 keV
- The pulse fraction increases with energy.
- Spin up rate ~8.4 e-13 Hz/s
- Soft lags with complex structure
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Burderi et al. 2007,ApJ : - pulse frequency = 598.89213053(2) Hz.
- spin-up frequency = 8.5 e-13 Hz/s. (depending on modeling, 0.85, 1.17 or 1.11 e-12)
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Linares et al. 2007:
- power density spectra typical of low luminosity and hard spectral
state of Atoll sources (flat top noise, below a break frequency,
3 broad lorentzians to account for features at Nu> Nu break, and
2 LF QPOs)
- overall 0.1-100 Hz fractional
rms amplitude is very high (42-58 %)
- no significant power at frequencies > 100 Hz.
- Properties of aperiodic variability typical of BHs
- results refute a simple mass-frequency
relation for the variability components of LMXBs
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D'Avanzo et al. 2007:
- Optical and Infra red observations of the field
around IGR J00291+5934 during quiescence.
- Detect the source in VRIJ and H bands
while provide an upper limit in K.
- The reported magnitudes are :
V=24.0, R=23.2, I=22.4, J=21.4, H=20.4 and K> 19.3 (3sig)
- Variability of the source at a period consistent
with the orbital period of the system.
- SED fitting=> Optical/NIR quiescent luminosity can be modeled with a
irradiated companion star.
- Deduce a lower limit to the B field of the pulsar, B> 6e7 G.
- Only way to obtain the irradiated luminosity => energy is provided by
the rotational energy of the NS emitted in the form of a
relativistic particle wind.
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Torres et al. 2008:
- Optical, near infrared and X-ray observations
- Rate of decline of 5.2 day/mag in the R band => peak brightness
of R=17.03 mag
- The magnitude of the counterpart in quiscence is determined to R=23.1
- Emission lines in the spectra of the counterpart
- SED => near infrared excess that may be due to a jet.
- Quiescence =>(0.5-10 keV) flux is 7.9e-14 erg/cm2/s with some variability
- Inclination angle between 22 and 32 degrees,
- Mass of the donor between 0.04 and 0.11 solar masses (for a 1.4 Msol
neutron star)
- Distance between 2 and 3.4 kpc
- B<3e8 G.
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Jonker et al. 2008:
- I-Band optical and Chandra observations
- Source inquiescence, unabsorbed F0.5-10 keV= 10-13 erg/cm2/s
- I-band lightcurve shows evidence for a strong flaring activity.
- Sinusoidal modulation of I-band lc => result of superhump
- Differences in quiescent level with previous obs.
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Seen with RXTE (Chakrabarti et al. 2008
ATel 1660), Swift (Markwardt & Swank 2008 ATel 1664, and Marshall et al. ATel 1668), and in Optical the source has brightened by more
than 4 magnitudes (Torres et al. 2008:
ATel 1665, Russel et al. 2008:
ATel 1666). But not detected in radio at 4.9 GHz with a 3-σ
upper limit of 160µJy (Linares et al. 2008 ATel 1667
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Lewis et al. 2008:
ATel
1726
- re-brigthening in optical and X-rays
- Renewed activity of the source was first seen in optical
on 18th September with a detection at i' = 17.38 <=>~0.2 mag fainter
than the outburst peak on 15th August.
- Swift pointing confirmed the re-brightening: X-ray flux is
a factor of ~2 fainter than that of the peak in august.
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Galloway et al. 2008:
ATel
1786
- Short summary of last outburst
- Double outburst seen with RXTE at X-ray energies, and in optical.
- First maximum between Aug 13 and 15, at a 2.5-25 level of 6.3e-10 erg/cm^2/s.
- Decreased to ~7e-11 erg/cm^2/s by 21 Aug, and stayed at this low
luminosity level until mid-Sept.
- Optical counterpart had also faded significantly by Aug 24.
- Rebrightening in the optical and X-ray bands on Sep 18
- On Sept. 21 the 2.5-25 keV flux =2.3e-10 erg/cm^2/s, and pulsations
were detected again
- 2nd peak had a flux of 5e-10 erg/cm^2/s and occured between Sep 24 and 26.
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Campana et al. 2008:
- First observation of thermal emission from an accreting MXP while in quiescence (XMM obs)
- Either neutron star atmosphere (64 eV) or a black body (110 eV)
- Thermal emission compatible with cooling of the neutron star surface
- Neutron star Mass < 1.6 sol Masses
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Lewis et al. 2010: (A&A)
- Multi-wavelength analysis (from radio to X-rays, + most detailed IR-UV SED of an AMXP)
of 2008 double-peaked outburst
- First peak (Aug. 2008) exhibits a rapid decline, whereas the second peak (Sep., 2008),
has a shape similar to the 2004 outburst (optical)
- Plateau phase lasting ~10 days that also present in the X-rays
- No periodicities seen in light curve (even atorbital period of 2.46 hours)
- Optical spectrum = blue component plus a double-peaked H-alpha profile => typical of an irradiated
accretion disk
- Transient NIR excess consistent with an optically-thin synchrotron jet
- Discussion on the morphology of the double-peaked outburst in relation to the more
common single-peaked outbursts
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Papitto et al. 2011: (A&A)
- RXTE observations => estimate the neutron star spin (~598.892 ms) over 3 period of observations (2004,
2008a and 2008b outbursts)
- Refine orbital solution of the system
- Measure spin up of the source during outbursts
- Discover source spins down during period of quiescence (average rate -4.1e-15 Hz/s)
- Favour model based of magneto dipole emission as the origin of the spin down
- In this framework => upper limit to the magnetic field B<3e8 G.
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Sanna et al. 2015 ATel
7836:
- New outburst => Swift ToO
- absorbed power law to fit XRT spectrum => NH=7 E21 cm-2 Γ=1.4
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Kuin et al. 2015 ATel
7849:
- Further Swift observation
- Enhanced UVOT position to RA = 7.26275°, Dec = 59.57198° ± 0.43"
- 1st snapshot of data parameterised by exponential decay, with efold time=115s
- Absorbed black body with kT 1.2 keV provides slightly better fit than power law
- Consistent with cooling tail of type I burst => first one ever reported for this source
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Bozzo et al. 2015 ATel
7852:
- Time resolved analysis of Swift XRT observations during the burst.
- All spectra well fitted by absorbed black body
- BB temperature decreasing from 1.8 to 1.01 keV
- Supposed Duration of burst longer than typical H burst => ignited in a pure layer of He
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