Debeamed Sequence of LBAS Blazars

Huang, Bangrong; Zhang, Xiong; Xiong, Dongbin; Zhang, Haojin

doi:10.1007/s12036-014-9235-7

Cited by 4 publications

(4 citation statements)

References 10 publications

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“…A more convincing case for a magnetar antiglitch, with ∆ ν/ν = −3 × 10 −7 and connected with a flux increase, has been recently reported for 1E 2259+586 (Archibald et al 2013). This prompted several interpretations, involving either a sudden event, like the collision with a solid body (Huang & Geng 2014), or a rapid reconfiguration of the magnetosphere with the opening of some of the closed field lines and the emission of an enhanced particle wind (Lyutikov 2013;Tong 2014).…”

Section: X-ray Pulsationsmentioning

confidence: 99%

Magnetars: Properties, Origin and Evolution

2015

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Magnetars are neutron stars in which a strong magnetic field is the main energy source. About two dozens of magnetars, plus several candidates, are currently known in our Galaxy and in the Magellanic Clouds. They appear as highly variable X-ray sources and, in some cases, also as radio and/or optical pulsars. Their spin periods (2-12 s) and spin-down rates (~10^{-13}-10^{-10} s/s) indicate external dipole fields of ~10^{13-15} G, and there is evidence that even stronger magnetic fields are present inside the star and in non-dipolar magnetospheric components. Here we review the observed properties of the persistent emission from magnetars, discuss the main models proposed to explain the origin of their magnetic field and present recent developments in the study of their evolution and connection with other classes of neutron stars.Comment: 24 pages, 8 figures, invited topical review, to be published in The Strongest Magnetic Fields in the Universe (Space Sciences Series of ISSI, Springer), Space Science Review

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Section: X-ray Pulsationsmentioning

confidence: 99%

Magnetars: Properties, Origin and Evolution

2015

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Section: Photon Spectral Index Versus Luminositymentioning

confidence: 99%

“…As a result, there would be a positive correlation between the X-ray luminosity and X-ray photon spectral index, as demonstrated in the panel (5) of Figure 4 (the Spearman's ranking correlation for the overall α-L 3-25keV,observed relation of the five sources is 0.31 with a significance of 3.42 ×10 -13 ). However, the anti-correlation between synchrotron peak energy and luminosity (the blazar sequence) dispears after applying Doppler boosting correction to the observed luminosity (e.g., Nieppola et al 2008;Wu et al 2009;Huang et al 2014;Fan et al 2017). In this work, we performed approximate Doppler-corrections using the equation L intrinsic = L observed /δ 3 , where L intrinsic is the intrinsic luminosity, L observed is the observed luminosity and δ is the lower limit of the γ-ray Doppler factor from Fan et al (2013) that is estimated according to the pairproduction optical depth (Mattox et al 1993): 2.77 for Mrk 421, 2.83 for Mrk 501, 4.15 for PKS 2155-304, 3.30 for PKS 2005-489 and 2.32 for 1ES 1959+650.…”

Section: Photon Spectral Index Versus Luminositymentioning

confidence: 99%

Systematic Investigation of X-Ray Spectral Variability of TeV Blazars during Flares in the RXTE Era

Wang

Xue

Zhu

et al. 2018

ApJ

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Utilizing all the 16-year RXTE observations, we analyze the X-ray spectra of 32 TeV blazars, and perform a systematic investigation of X-ray spectral variability for the 5 brightest sources during their major flares that lasted several days. We obtain photon spectral index (α), flux and synchrotron radiation peak energy (E p ) from empirical spectral fitting, and electron spectral index (p) from theoretical synchrotron radiation modeling. We find that both α and p generally display a harder-when-brighter trend, confirming the results of many previous works. Furthermore, we confirm and strengthen the result that p must vary in order to explain the observed X-ray spectral variability during flares, which would have useful implications for interpreting the associated higher-energy spectral variability. We see apparent electron spectral hysteresis in many but not all p-flux plots that takes a form of "loop" or oblique "8". We obtain a tight p-hardness ratio (HR) relation and a tighter p-α relation using spectra of flaring periods, both of which are also applicable to stacked data of quiescent periods. We demonstrate that these two empirical relations can be used efficiently to estimate p from HR or α that is readily achieved. Finally, we find that, when considering TeV blazars as a whole, α and X-ray luminosity are positively correlated, E p is negatively correlated with p and α, and E p is positively correlated with HR; all these correlations are in line with the blazar sequence. However, after correcting for the Doppler boosting effect, α and intrinsic X-ray luminosity follow an anti-correlation.

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“…For the entire blazar populations, there is an apparent anti-correlation between L p and E p , widely known as the blazar sequence (e.g., Fossati et al 1998;Ghisellini et al 1998;Chen & Bai 2011;Ghisellini et al 2017). However, it is suggested that this trend might be due to the selection bias (e.g., Giommi et al 2012) or might disappear after applying the Doppler boosting correction (e.g., Nieppola et al 2008;Wu et al 2009;Huang et al 2014;Fan et al 2017;Wang et al 2018). Blazars exhibit intense variability in all detectable wavelengths, which, for instance, is illustrated by their seemingly scale-invariant X-ray flares that last from years down to days and even to minutes (e.g., Cui 2004;Xue & Cui 2005;Zhu et al 2018).…”

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confidence: 99%

X-ray spectral variations of synchrotron peak in BL Lacs

Wang,

Zhu,

Xue

et al. 2019

Preprint

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The spectral energy distribution of blazars around the synchrotron peak can be well described by the logparabolic model that has three parameters: peak energy (E p ), peak luminosity (L p ) and the curvature parameter (b). It has been suggested that E p shows relations with L p and b in several sources, which can be used to constrain the physical properties of the emitting region and/or acceleration processes of the emitting particles. We systematically study the E p -L p and E p -(1/b) relations for 14 BL Lac objects using the 3-25 keV RXTE/PCA and 0.3-10 keV Swift/XRT data. Most objects (9/14) exhibit positive E p -L p correlations, three sources show no correlation, and two sources display negative correlations. In addition, most targets (7/14) present no correlation between E p and 1/b, five sources pose negative correlations, and two sources demonstrate positive correlations. 1ES 1959+650 displays two different E p -L p relations in 2002 and 2016. We also analyze E p -L p and E p -(1/b) relations during flares lasting for several days. The E p -L p relation does not exhibit significant differences between flares, while the E p -(1/b) relation varies from flare to flare. For the total sample, when L p < 10 45 erg s -1 , there seems to be a positive E p -L p correlation. L p and the slope of E p -L p relation present an anti-correlation, which indicates that the causes of spectral variations might be different between luminous and faint sources. E p shows a positive correlation with the black hole mass. We discuss the implications of these results.

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Debeamed Sequence of LBAS Blazars

Cited by 4 publications

References 10 publications

Magnetars: Properties, Origin and Evolution

Magnetars: Properties, Origin and Evolution

Systematic Investigation of X-Ray Spectral Variability of TeV Blazars during Flares in the RXTE Era

X-ray spectral variations of synchrotron peak in BL Lacs

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