IGR J00291+5934

Type Mass Radio Counterpart Infrared/Optical Counterpart
R.A. (J2000) Dec. (J2000) References R.A. (J2000) Dec. (J2000) References
Accreting millisecond pulsar
NS <1.6 Msol
  • 1.1 mJy @ 15 GHz (Ryle)
  • 0.250 mJy @ 5 GHz (WSRT later)
  • 0.17 mJy @ 4.86 GHz (VLA even later)
00h 29m 03.07s (±0.4") +59° 34' 19.12" (±0.4") Fox and Kulkarni 2004 Atel 354
D'avanzo et al. 2007 (this position)
Torres et al. 2007
Published Papers
Miscellaneous :

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
Remillard 2004 Atel 357: possible recurrence time of 3 years
Fox and Kulkarni 2004, Atel 354: R~17.4 in outburst
Roelofs et al. 2004 Atel 356: (Optical) emission lines features near the HeII line (4686 A) and near the Halpha line (6563 A)
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
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)
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
Shaw et al. 2005, A&A: Comptonised spectrum kTe~25 keV, and Tau~3.5
Bikmaev et al. 2005, Atel 395: Optical monitoring, exponential decay e-folding time~5.7 days. R light curve available here
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
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
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
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
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)
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
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.
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.
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.

New Outburst August 2008

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
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.
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.
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
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
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.
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
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
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

Last updated 4 Aug. 2015

Jerome Rodriguez