In this paper, we investigate the influences of two continuum radiation pressures of the central engines on the black hole mass estimates for 40 active galactic nuclei (AGNs) with high accretion rates. The two continuum radiation pressure forces, usu
ally believed negligible or not considered, are from the free electron Thomson scattering, and the recombination and re-ionization of hydrogen ions that continue to absorb ionizing photons to compensate for the recombination. The masses counteracted by the two radiation pressures $M_{rm{RP}}$ depend sensitively on the percent of ionized hydrogen in the clouds $beta$, and are not ignorable compared to the black hole virial masses $M_{rm{RM}}$, estimated from the reverberation mapping method, for these AGNs. As $beta$ increases, $M_{rm{RP}}$ also does. The black hole masses $M_{rm{bullet}}$ could be underestimated at least by a factor of 30--40 percent for some AGNs accreting around the Eddington limit, regardless of redshifts of sources $z$. Some AGNs at $z < 0.3$ and quasars at $z ga 6.0$ have the same behaviors in the plots of $M_{rm{RP}}$ versus $M_{rm{RM}}$. The complete radiation pressures will be added as AGNs match $M_{rm{RP}}ga 0.3 M_{rm{RM}}$ due to the two continuum radiation pressures. Compared to $M_{rm{RM}}$, $M_{rm{bullet}}$ might be extremely underestimated if considering the complete radiation pressures for the AGNs accreting around the Eddington limit.
By means of oxide molecular beam epitaxy with shutter-growth mode, we have fabricated a series of electron-doped (Sr1-xLax)2IrO4(001)(x = 0, 0.05, 0.1 and 0.15) single crystalline thin films and then investigated the doping dependence of electronic s
tructure utilizing in-situ angle-resolved photoemission spectroscopy. We find that with increasing doping proportion, the Fermi levels of samples progressively shift upward. Prominently, an extra electron pocket crossing the Fermi level around the M point has been evidently observed in 15 % nominal doping sample. Moreover, bulk-sensitive transport measurements confirm that doping effectively suppresses the insulating state with respect to the as-grown Sr2IrO4, though doped samples still remain insulating at low temperatures due to the localization effect possibly stemming from disorders including oxygen deficiencies. Our work provides another feasible doping method to tune electronic structure of Sr2IrO4.
In this paper, we investigated the issue of black hole masses and minimum timescales of jet emission for blazars. We proposed a sophisticated model that sets an upper limit to the central black hole masses $M_{bullet}$ with the minimum timescales $De
lta t^{rm{ob}}_{rm{min}}$ of variations observed in blazars. The value of $Delta t^{rm{ob}}_{rm{min}}$ presents an upper limit to the size of blob in jet. The blob is assumed to be generated in the jet-production region in the vicinity of black hole, and then the expanding blob travels outward along the jet. We applied the model to 32 blazars, 29 of which were detected in gamma rays by satellites, and these $Delta t^{rm{ob}}_{rm{min}}$ are on the order of hours with large variability amplitudes. In general, these $M_{bullet}$ estimated with this method are not inconsistent with those masses reported in the literatures. This model is natural to connect $M_{bullet}$ with $Delta t^{rm{ob}}_{rm{min}}$ for blazars, and seems to be applicable to constrain $M_{bullet}$ in the central engines of blazars.
The remarkable scientific return and legacy of LSST, in the era that it will define, will not only be realized in the breakthrough science that will be achieved with catalog data. This Big Data survey will shape the way the entire astronomical commun
ity advances -- or fails to embrace -- new ways of approaching astronomical research and data. In this white paper, we address the NRC template questions 4,5,6,8 and 9, with a focus on the unique challenges for smaller, and often under-resourced, institutions, including institutions dedicated to underserved minority populations, in the efficient and effective use of LSST data products to maximize LSSTs scientific return.
Quantum phase transitions play an important role in many-body systems and have been a research focus in conventional condensed matter physics over the past few decades. Artificial atoms, such as superconducting qubits that can be individually manipul
ated, provide a new paradigm of realising and exploring quantum phase transitions by engineering an on-chip quantum simulator. Here we demonstrate experimentally the quantum critical behaviour in a highly-controllable superconducting circuit, consisting of four qubits coupled to a common resonator mode. By off-resonantly driving the system to renormalise the critical spin-field coupling strength, we have observed a four-qubit non-equilibrium quantum phase transition in a dynamical manner, i.e., we sweep the critical coupling strength over time and monitor the four-qubit scaled moments for a signature of a structural change of the systems eigenstates. Our observation of the non-equilibrium quantum phase transition, which is in good agreement with the driven Tavis-Cummings theory under decoherence, offers new experimental approaches towards exploring quantum phase transition related science, such as scaling behaviours, parity breaking and long-range quantum correlations.
In the paper, we investigate correlation between broad-line and radio variations for broad-line radio galaxy 3C 120. By the z-transformed discrete correlation function method and the model-independent flux randomization/random subset selection (FR/RS
S) Monte Carlo method, we find that the broad Hbeta line variations lead the 15 GHz variations. The FR/RSS method shows that the Hbeta line variations lead the radio variations by a factor of tau_{ob}=0.34 +/- 0.01 yr. This time lag can be used to locate the position of emitting region of radio outbursts in jet, on the order of ~ 5 light-years, from the central engine. This distance is much larger than the size of broad-line region. The large separation of the radio outburst emitting region from the broad-line region will observably influence the gamma-ray emission in 3C 120.
The comprehensive study of the temperature dependent x-ray absorption spectroscopy (XAS) reveals a dynamical spectral weight $alpha$ in YBa$_2$Cu$_3$O$_y$ (YBCO). Large spectral weight changes for both the Upper Hubbard band and the Zhang-Rice band d
ue to dynamics of holes are experimentally found in the underdoped regime. A large value of $alpha geq 0.3$ is indispensable to describing XAS of YBCO with the conservation of states. The value of $alpha$ is linearly proportional to the pseudogap temperature in the underdoped regime, but becomes smaller as the doping level goes to the undoped limit. Our results clearly indicate that the pseudogap is related to the double occupancy and originates from bands in higher energies.
We propose and explore a stationary 1+log slicing condition for the construction of solutions to Einsteins constraint equations. For stationary spacetimes, these initial data will give a stationary foliation when evolved with moving puncture gauge co
nditions that are often used in black hole evolutions. The resulting slicing is time-independent and agrees with the slicing generated by being dragged along a time-like Killing vector of the spacetime. When these initial data are evolved with moving puncture gauge conditions, numerical errors arising from coordinate evolution are minimized. In the construction of initial data for binary black holes it is often assumed that there exists an approximate helical Killing vector that generates the binarys orbit. We show that, unfortunately, 1+log slices that are stationary with respect to such a helical Killing vector cannot be asymptotically flat, unless the spacetime possesses an additional axial Killing vector.
In pp collisions at 1.25 GeV kinetic energy, the HADES collaboration aimed at investigating the di-electron production related to $Delta$ (1232) Dalitz decay ($Delta^+ to pe^+e^-$). In order to constrain the models predicting the cross section and th
e production mechanisms of $Delta$ resonance, the hadronic channels have been measured and studied in parallel to the leptonic channels. The analyses of $ppto nppi^+$ and $ppto pppi^0$ channels and the comparison to simulations are presented in this contribution, in particular the angular distributions being sensitive to $Delta$ production and decay. The accurate acceptance corrections have been performed as well, which could be tested in all the phase space region thanks to the high statistic data. These analyses result in an overall agreement with the one-$pi$ exchange model and previous data.
We demonstrated for the first time the characterization of absolute frequency stability of three reference cavities by cross beating three laser beams which are independently locked to these reference cavities. This method shows the individual featur
e of each reference cavity, while conventional beatnote measurement between two cavities can only provide an upper bound. This method allows for numerous applications such as optimizing the performance of the reference cavity for optical clockwork.
