TY - JOUR
T1 - Extremely Rapid X-Ray Flares of TeV Blazars in the RXTE Era
AU - Zhu, S. F.
AU - Xue, Y. Q.
AU - Brandt, W. N.
AU - Cui, W.
AU - Wang, Y. J.
N1 - Funding Information:
We thank the anonymous referee for his/her helpful comments that improved the paper. S.F.Z., Y.Q.X., and Y.J. W. acknowledge support from the 973 Program (2015CB857004), NSFC-11473026, NSFC-11421303, the CAS Frontier Science Key Research Program (QYZDJ-SSWSLH006), and the Fundamental Research Funds for the Central Universities. S.F.Z. and W.N.B. acknowledge support from Chandra X-ray Center grant G04-15093X.
Funding Information:
We thank the anonymous referee for his/her helpful comments that improved the paper. S.F.Z., Y.Q.X., and Y.J. W. acknowledge support from the 973 Program (2015CB857004), NSFC-11473026, NSFC-11421303, the CAS Frontier Science Key Research Program (QYZDJ-SSW-SLH006), and the Fundamental Research Funds for the Central Universities. S.F.Z. and W.N.B. acknowledge support from Chandra X-ray Center grant G04-15093X.
Publisher Copyright:
© 2018. The American Astronomical Society. All rights reserved.
PY - 2018/1/20
Y1 - 2018/1/20
N2 - Rapid flares from blazars in very high-energy (VHE) γ-rays challenge the common understanding of jets of active galactic nuclei (AGNs). The same population of ultra-relativistic electrons is often thought to be responsible for both X-ray and VHE emission. We thus systematically searched for X-ray flares at sub-hour timescales of TeV blazars in the entire Rossi X-ray Timing Explorer archival database. We found rapid flares from PKS 2005-489 and S5 0716+714, and a candidate rapid flare from 1ES 1101-232. In particular, the characteristic rise timescale of PKS 2005-489 is less than half a minute, which, to our knowledge, is the shortest among known AGN flares at any wavelengths. The timescales of these rapid flares indicate that the size of the central supermassive black hole is not a hard lower limit on the physical size of the emission region of the flare. PKS 2005-489 shows possible hard lags in its flare, which could be attributed to particle acceleration (injection); its flaring component has the hardest spectrum when it first appears. For all flares, the flaring components show similar hard spectra with , and we estimate the magnetic field strength B ∼ 0.1-1.0 G by assuming synchrotron cooling. These flares could be caused by inhomogeneity of the jets. Models that can only produce rapid γ-ray flares but little synchrotron activity are less favorable.
AB - Rapid flares from blazars in very high-energy (VHE) γ-rays challenge the common understanding of jets of active galactic nuclei (AGNs). The same population of ultra-relativistic electrons is often thought to be responsible for both X-ray and VHE emission. We thus systematically searched for X-ray flares at sub-hour timescales of TeV blazars in the entire Rossi X-ray Timing Explorer archival database. We found rapid flares from PKS 2005-489 and S5 0716+714, and a candidate rapid flare from 1ES 1101-232. In particular, the characteristic rise timescale of PKS 2005-489 is less than half a minute, which, to our knowledge, is the shortest among known AGN flares at any wavelengths. The timescales of these rapid flares indicate that the size of the central supermassive black hole is not a hard lower limit on the physical size of the emission region of the flare. PKS 2005-489 shows possible hard lags in its flare, which could be attributed to particle acceleration (injection); its flaring component has the hardest spectrum when it first appears. For all flares, the flaring components show similar hard spectra with , and we estimate the magnetic field strength B ∼ 0.1-1.0 G by assuming synchrotron cooling. These flares could be caused by inhomogeneity of the jets. Models that can only produce rapid γ-ray flares but little synchrotron activity are less favorable.
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U2 - 10.3847/1538-4357/aa9f21
DO - 10.3847/1538-4357/aa9f21
M3 - Article
AN - SCOPUS:85041130515
SN - 0004-637X
VL - 853
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 34
ER -