Broadband spectral energy distributions (SEDs) simultaneously or quasisimultaneously observed with Fermi/LAT and the other instruments are complied from literature for 24 TeV BL Lac objects. Two SEDs are available for each of 11 objects, and the state of the sources is identified as a low or high state according to its flux density at 1 TeV. The well-sampled, clean SEDs without contaminations of the accretion disk and external Compton process of these sources are the best candidates for investigating the radiation mechanisms and the physical properties of the jets. Assuming that the electron spectrum is a broken power-law with a break at γ b and using the peak frequencies and their corresponding lumminosities (ν s , ν c , L s , and L c ) of the SEDs, we fit the SEDs with the single-zone synchrotron + synchrotron-self-Compton (SSC) model and determine the physical parameters of the jets, including the Doppler boosting factor (δ), the magnetic field strength (B), the size of radiating region (R), the bolometric luminosity (L bol ), and the jet total power (P jet ). The model well represents the SEDs, and the observed relation between ν s and ν c also favors the model. In this scenario, we find that γ b is significantly different among sources and even among the low and high states of a given source, but B is distributed narrowly within the range of 0.1−0.6 G, indicating that the shocks in the jets are significantly different among sources and the magnetic field may be independent of the shocks. δ ranges from 14 to 30, and R = (2.6 ∼ 100) × 10 15 cm, suggesting that flux variations with a minimum timescale from an hour to one day may be observed for these sources. Prominent flux variations with a clear spectral shift are observed and the ratio of the flux density at 1 TeV is correlated with the ratio of the γ b in the low and high states, indicating that the relativistic shocks in the jets may be responsible for the flux variations and the spectral shift. δ of the high state is systematically larger than that of the low state, but the ratios of δ and the flux density in the high and low states are not correlated. The ratio of L c /L s is anti-correlated with ν s in the co-moving frame for the sources in both the high and low states, but the slopes of the anti-correlations are significantly different. This anti-correlation is possibly due to the Klein-Nishina effect, but not the cooling effect of the photon fields outside the jet, as proposed for explaining the blazar sequence. No excess in the GeV band due to the interaction between the TeV photons and the extragalactic background light is observed, implying that the strength of the intergalactic magnetic field would be much larger than 10 −16 G. The observed L bol is not correlated with P jet . An anti-correlation between P jet and the mass of the central black hole is observed, i.e., P jet ∝ M −1 BH , disfavoring the scenario of a pure accretion-driven jet. We suggest that the spin energy extraction may be significant for powering jets in these sources, implying t...
In the sixth of the series of papers reporting on a large reverberation mapping (RM) campaign of active galactic nuclei (AGNs) with high accretion rates, we present velocity-resolved time lags of Hβ emission lines for nine objects observed in the campaign during 2012−2013. In order to correct the line-broadening caused by seeing and instruments before the analysis of velocity-resolved RM, we adopt Richardson-Lucy deconvolution to reconstruct their Hβ profiles. The validity and effectiveness of the deconvolution are checked out by Monte Carlo simulation. Five among the nine objects show clear dependence of time delay on velocity. Mrk 335 and Mrk 486 show signatures of gas inflow whereas the clouds in the broad-line regions (BLRs) of Mrk 142 and MCG +06-26-012 tend to be radial outflowing. Mrk 1044 is consistent with the case of virialized motions. The lags of the rest four are not velocity-resolvable. The velocity-resolved RM of super-Eddington accreting massive black holes (SEAMBHs) shows that they have diversity of the kinematics in their BLRs. Comparing with the AGNs with sub-Eddington accretion rates, we do not find significant differences in the BLR kinematics of SEAMBHs.
A fraction of the heavily reddened quasars require a reddening curve which is even steeper than that of the Small Magellanic Cloud. In this paper, we thoroughly characterize the anomalously steep reddening law in quasars, via an exceptional example observed in IRAS 14026+4341. By comparing the observed spectrum to the quasar composite spectrum, we derive a reddening curve in the rest-frame wavelength range of 1200Å-10000Å. It is featured with a steep rise at wavelengths shorter than 3000Å, but no significant reddening at longer wavelengths. The absence of dust reddening in optical continuum is confirmed by the normal broad-line Balmer decrement (the Hα/Hβ ratio) in IRAS 14026+4341. The anomalous reddening curve can be satisfactorily reproduced by a dust model containing silicate grains in a power-law size distribution, dn(a)/da ∝ a −1.4 , truncated at a maximum size a max = 70 nm. The unusual size distribution may be caused by the destruction of large "stardust" grains by quasar activities or a different dust formation mechanism (i.e., the in situ formation of dust grains in quasar outflows). It is also possible that the analogies of the dust grains observed toward the Galactic center is responsible for the steep reddening curve. In addition, we find that IRAS 14026+4341 is a weak emission-line quasar (i.e., PHL 1811 analogies) with heavy dust reddening and blueshifted broad absorption lines.
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