Intensive disc-reverberation mapping of Fairall 9: first year of Swift and LCO monitoring

ABSTRACT We present results of time-series analysis of the first year of the Fairall 9 intensive disc-reverberation campaign. We used Swift and the Las Cumbres Observatory global telescope network to continuously monitor Fairall 9 from X-rays to near-infrared at a daily to subdaily cadence. The cross-correlation function between bands provides evidence for a lag spectrum consistent with the τ ∝ λ4/3 scaling expected for an optically thick, geometrically thin blackbody accretion disc. Decomposing the flux into constant and variable components, the variable component’s spectral energy distribution is slightly steeper than the standard accretion disc prediction. We find evidence at the Balmer edge in both the lag and flux spectra for an additional bound-free continuum contribution that may arise from reprocessing in the broad-line region. The inferred driving light curve suggests two distinct components, a rapidly variable (<4 d) component arising from X-ray reprocessing, and a more slowly varying (>100 d) component with an opposite lag to the reverberation signal.

Charm quark mass determined from a pair of sum rules

In this paper, we present preliminary results of the determination of the charm quark mass [Formula: see text] from QCD sum rules of moments of the vector current correlator calculated in perturbative QCD at [Formula: see text]. Self-consistency between two different sum rules allow to determine the continuum contribution to the moments without requiring experimental input, except for the charm resonances below the continuum threshold. The existing experimental data from the continuum region is used, then, to confront the theoretical determination and reassess the theoretic uncertainty.

THE CONTINUUM AND INTERFERENCE EFFECT IN $e^+e^-\to D^0\bar{D}^0$, D+D- Processes

In the e+e- annihilation processes [Formula: see text], D+D- near or above the threshold of [Formula: see text], there are not only the resonance contribution [Formula: see text], D+D-, but also the continuum contribution through virtual photon directly [Formula: see text], D+D-. The amplitudes through virtual photon directly and through resonance can interfere seriously. We consider the continuum and interference effect in the [Formula: see text] production process in e+e- annihilation. We find that the effect is significant near and above the threshold of the [Formula: see text] mesons.

Dust Properties of Planetary Nebulae

Shells of planetary nebulae (PNe) are usually modeled applying photoionization only although there is a significant fraction of dust embedded in the nebular shells. The calculated temperature and dust-to-gas ratio from IRAS colors is “faked” by the IR flux continuum contribution from the gas and by transiently heated dust grains. Also the effects of grain growth time and thus maximum grain size lead to strong deviations from the model input values, adopting the IRAS data fits.