Uniting the Quiescent Emission and Burst Spectra of Magnetar Candidates

Nakagawa, Y. E.; Yoshida, A.; Yamaoka, K.; Shibazaki, N.

doi:10.1093/pasj/61.1.109

Cited by 31 publications

(52 citation statements)

References 90 publications

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“…Interestingly a similar correlation between the hot and cool BB for AXPs and SGRs has been observed (Nakagawa et al 2009, see their …”

Section: The 2 Blackbodies In Quiescencesupporting

confidence: 73%

See 1 more Smart Citation

Quark-nova remnants

Ouyed¹,

Leahy²,

Niebergal³

2010

A&A

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XTE J1810−197 and 1E 1547.0−5408 are two transient anomalous X-rays pulsars (AXPs) exhibiting radio emission with unusual properties. In addition, their spin down rates during outburst show opposite trends, which so far has no explanation. Here, we extend our quark-nova model for AXPs to include transient AXPs, in which the outbursts are caused by transient accretion events from a Keplerian (iron-rich) degenerate ring. For a ring with inner and outer radii of 23.5 km and 26.5 km, respectively, our model gives a good fit to the observed X-ray outburst from XTE J1810−197 and the behavior of temperature, luminosity, and area of the two X-ray blackbodies with time. The two blackbodies in our model are related to a heat front (i.e. Bohm diffusion front) propagating along the ring's surface and an accretion hot spot on the quark star surface. Radio pulsations in our model are caused by dissipation at the light cylinder of magnetic bubbles, produced near the ring during the X-ray outburst. The delay between X-ray peak emission and radio emission in our model is related to the propagation time of these bubbles to the light cylinder and scale with the period as t prop. ∝ P 7 2 − α 2 /Ṗ 1/2 where α defines the radial dependence of matter density in the magnetosphere (∝r −α ); for an equatorial wind, α = 1, we predict a ∼1 year and ∼1 month delay for XTE J1810−197 and 1E 1547.0−5408, respectively. The observed flat spectrum, erratic pulse profile, and the pulse duration are all explained in our model as a result of X-point reconnection events induced by the dissipation of the bubbles at the light cylinder. The spin down rate of the central quark star can either increase or decrease depending on how the radial drift velocity of the magnetic islands changes with distance from the central star. We suggest an evolutionary connection between transient AXPs and typical AXPs in our model.

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“…Interestingly a similar correlation between the hot and cool BB for AXPs and SGRs has been observed (Nakagawa et al 2009, see their …”

Section: The 2 Blackbodies In Quiescencesupporting

confidence: 73%

“…We suggest, the relations in Fig. 6 in Nakagawa et al (2009) can be explained in the context of reprocessing during both quiescence and burst. .…”

Section: Model Features and Predictionsmentioning

confidence: 69%

Quark-nova remnants

Ouyed¹,

Leahy²,

Niebergal³

2010

A&A

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“…b Preceding Suzaku studies: SGR 1806−20 (Esposito et al 2007;Nakagawa et al 2009), 1E 1841−45 (Morii et al 2010), SGR 1900+14 (Nakagawa et al 2009) 4U 0142+61 Makishima et al 2014), AX J1818.8−586 (Mereghetti et al 2012), 1E 1547.0−5408 (Enoto et al 2010b;Iwahashi et al 2013;Enoto et al 2012;Makishima et al 2015), SGR 0501+4516 (Enoto et al 2009(Enoto et al , 2010cNakagawa et al 2011) CXOU J164710.2−455216 (Naik et al 2008), SGR 1833−0832 ), Swift J1822.3−1606, and Paper I. c Objects are sorted by the dipole field B d calculated from the period P and its derivativeṖ assuming the magnetic dipole radiation. d Type of observations: PV (Performance Verification phase, i.e., first 9 month after the launch), AO (Announcement of Opportunity observations), ToO (Target of Opportunity observations), and Key (Key Project observations).…”

Section: Reduction Of Broad-band Suzaku Spectramentioning

confidence: 99%

Magnetar Broadband X-Ray Spectra Correlated with Magnetic Fields: Suzaku Archive of SGRs and AXPs Combined with NuSTAR, Swift, and RXTE

Enoto¹,

Shibata²,

Kitaguchi³

et al. 2017

ApJS

116

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Studies were made of the 1-70 keV persistent spectra of fifteen magnetars as a complete sample observed with Suzaku from 2006 to 2013. Combined with early NuSTAR observations of four hard X-ray emitters, nine objects showed a hard power-law emission dominating at 10 keV with the 15-60 keV flux of ∼1-11 × 10 −11 ergs s −1 cm −2 . The hard X-ray luminosity L h , relative to that of a soft-thermal surface radiation L s , tends to become higher toward younger and strongly magnetized objects. Updated from the previous study, their hardness ratio, defined as ξ = L h /L s , is correlated with the measured spin-down rateṖ as ξ = 0.62 × (Ṗ /10 −11 s s −1 ) 0.72 , corresponding with positive and negative correlations of the dipole field strength B d (ξ ∝ B d) and the characteristic age τ c (ξ ∝ τ −0.68 c ), respectively. Among our sample, five transients were observed during X-ray outbursts, and the results are compared with their long-term 1-10 keV flux decays monitored with Swift/XRT and RXTE/PCA. Fading curves of three bright outbursts are approximated by an empirical formula used in the seismology, showing a ∼10-40 d plateau phase. Transients show the maximum luminosities of L s ∼1035 erg s −1 , which is comparable to those of the persistently bright ones, and fade back to 10 32 erg s −1 . Spectral properties are discussed in a framework of the magnetar hypothesis.

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“…where we adopted a surface magnetic field strength of B 0 2× 10 15 G (Nakagawa et al 2009). Incidentally, the synchrotron cooling time will decrease in the case of a globally twisted magnetic field (Thompson et al 2002).…”

Section: Synchrotron Cooling Time and Lower Limit To The Size Of The Comentioning

confidence: 99%

Magnetar giant flare high-energy emission

Elenbaas

Huppenkothen

Omand

et al. 2017

Monthly Notices of the Royal Astronomical Society

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High energy (> 250 keV) emission has been detected persisting for several tens of seconds after the initial spike of magnetar giant flares. It has been conjectured that this emission might arise via inverse Compton scattering in a highly extended corona generated by super-Eddington outflows high up in the magnetosphere. In this paper we undertake a detailed examination of this model. We investigate the properties of the required scatterers, and whether the mechanism is consistent with the degree of pulsed emission observed in the tail of the giant flare. We conclude that the mechanism is consistent with current data, although the origin of the scattering population remains an open question. We propose an alternative picture in which the emission is closer to that star and is dominated by synchrotron radiation. The RHESSI observations of the December 2004 flare modestly favor this latter picture. We assess the prospects for the Fermi Gamma-Ray Space Telescope to detect and characterize a similar high energy component in a future giant flare. Such a detection should help to resolve some of the outstanding issues.

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Uniting the Quiescent Emission and Burst Spectra of Magnetar Candidates

Cited by 31 publications

References 90 publications

Quark-nova remnants

Quark-nova remnants

Magnetar Broadband X-Ray Spectra Correlated with Magnetic Fields: Suzaku Archive of SGRs and AXPs Combined with NuSTAR, Swift, and RXTE

Magnetar giant flare high-energy emission

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