The Radio and Gamma-Ray Luminosities of Blazars

Based on the $\gamma$-ray data of blazars in the third EGRET catalog and radio data at 5 GHz, we studied the correlation between the radio and $\gamma$-ray luminosities using two statistical methods. The first method was the partial correlation analysis method, which indicates that there exist correlations between the radio and $\gamma$-ray luminosities in both high and low states as well as in the average case. The second method involved a comparison of expected $\gamma$-ray luminosity distribution with the observed data using the Kolmogorov-- Smirnov (KS) test. In the second method, we assumed that there is a correlation between the radio and $\gamma$-ray luminosities and that the $\gamma$-ray luminosity function is proportional to the radio luminosity function. The KS test indicates that the expected gamma-ray luminosity distributions are consistent with the observed data in a reasonable parameter range. Finally, we used different $\gamma$-ray luminosity functions to estimate the possible 'observed' $\gamma$-ray luminosity distributions by GLAST.Comment: 8 pages, 4 figures, one table, PASJ, 53 (2001

Cue validity and object-based attention

In a previous study, Egly, Driver, and Rafal (1994) observed both space- and object-based components of visual selective attention. However, the mechanisms underlying these two components and the relationship between them are not well understood. In the present research, with a similar paradigm, these issues were addressed by manipulating cue validity. Behavioral results indicated the presence of both space- and object-based components under high cue validity, similar to the results of Egly et al.'s study. In addition, under low cue validity, the space-based component was absent, whereas the object-based component was maintained. Further event-related potential results demonstrated an object-based effect at a sensory level over the posterior areas of brain, and a space-based effect over the anterior region. The present data suggest that the space- and object-based components reflect mainly voluntary and reflexive mechanisms, respectively

Polarization and Variations of BL Lacertae Objects

BL Lacertae objects are an extreme subclass of AGNs showing rapid and large-amplitude variability, high and variable polarization, and core-dominated radio emissions. If a strong beaming effect is the cause of the extreme observation properties, one would expect that these properties would be correlated with each other. Based on the relativistic beaming model, relationships between the polarization and the magnitude variation in brightness, as well as the core- dominance parameter are derived and used statistically to compare with the observational data of a BL Lacertae object sample. The statistical results are consistent with these correlations, which suggests that the polarization, the variation, and the core-dominance parameter are possible indications of the beaming effect.Comment: 6 pages, two figures, one table, some revisions. PASJ, 53 (2001

Basic properties of Gamma-ray loud blazars

In this paper, a method is proposed to determine the basic properties of $\gamma$-ray loud blazars, among them the central black hole mass, M, the Doppler factor, $\delta$, the propagation angle of the $\gamma$-rays with respect to the symmetric axis of a two-temperature accretion disk, $\Phi$, and the distance (i.e. the height above the accretion disk), d at which the $\gamma$-rays are created, for seven $\gamma$-ray loud blazars with available GeV variability timescales and in which the absorption effect of a $\gamma$-ray and the beaming effect have been taken into account. Our results indicate that, if we take the intrinsic $\gamma$-ray luminosity to be $\lambda$ times the Eddington luminosity, $L_{\gamma}^{in} = \lambda L_{Edd.}$, the masses of the blazars are in the range of $(4 \sim 131)\times 10^{7}M_{\odot}$, the Doppler factors ($\delta$) lie in the range of 0.57 to 5.33 the angle ($\Phi$) is in the range of $13^{\circ}$ to 43$^{\circ}$ and the distance (d) is in the range of 26R_{g} to 411R_{g}. Our model results are independent of $\gamma$-ray emission mechanisms but they do depend on the X-ray emission mechanism of the accretion disk.Comment: 14 pages, 3 tables, A&A accepte

Entangled Husimi distribution and Complex Wavelet transformation

Based on the proceding Letter [Int. J. Theor. Phys. 48, 1539 (2009)], we expand the relation between wavelet transformation and Husimi distribution function to the entangled case. We find that the optical complex wavelet transformation can be used to study the entangled Husimi distribution function in phase space theory of quantum optics. We prove that the entangled Husimi distribution function of a two-mode quantum state |phi> is just the modulus square of the complex wavelet transform of exp{-(|eta|^2)/2} with phi(eta)being the mother wavelet up to a Gaussian function.Comment: 7 page

Into the central 10 pc of the most distant known radio quasar. VLBI imaging observations of J1429+5447 at z=6.21

Context: There are about 60 quasars known at redshifts z>5.7 to date. Only three of them are detected in the radio above 1 mJy flux density at 1.4 GHz frequency. Among them, J1429+5447 (z=6.21) is the highest-redshift radio quasar known at present. These rare, distant, and powerful objects provide important insight into the activity of the supermassive black holes in the Universe at early cosmological epochs, and on the physical conditions in their environment. Aims: We studied the compact radio structure of J1429+5447 on the milli-arcsecond (mas) angular scale, in order to compare the structural and spectral properties with those of other two z~6 radio-loud quasars, J0836+0054 (z=5.77) and J1427+3312 (z=6.12). Methods: We performed Very Long Baseline Interferometry (VLBI) imaging observations of J1429+5447 with the European VLBI Network (EVN) at 1.6 GHz on 2010 June 8, and at 5 GHz on 2010 May 27. Results: Based on its observed radio properties, the compact but somewhat resolved structure on linear scales of <100 pc, and the steep spectrum, the quasar J1429+5447 is remarkably similar to J0836+0054 and J1427+3312. To answer the question whether the compact steep-spectrum radio emission is a "universal" feature of the most distant radio quasars, it is essential to study more, yet to be discovered radio-loud active galactic nuclei at z>6.Comment: 4 pages, 2 figures, accepted for publication as a Letter to the editor in Astronomy & Astrophyic

The C IV Mass Density of the Universe at Redshift 5

In order to search for metals in the Lyman alpha forest at redshifts z > 4, we have obtained spectra of high S/N and resolution of three QSOs at z > 5.4 discovered by the Sloan Digital Sky Survey. These data allow us to probe to metal enrichment of the intergalactic medium at early times with higher sensitivity than previous studies. We find 16 C IV absorption systems with column densities log N(C IV) = 12.50 - 13.98 over a total redshift path Delta X = 3.29. In the redshift interval z = 4.5-5.0, where our statistics are most reliable, we deduce a comoving mass density of C IV ions Omega(C IV) = (4.3 +/- 2.5) x 10(-8) (90% confidence limits) for absorption systems with log N(C IV) > 13.0 (for an Einstein-de Sitter cosmology with h = 0.65). This value of Omega(C IV) is entirely consistent with those measured at z < 4; we confirm the earlier finding by Songaila (2001) that neither the column density distribution of C IV absorbers nor its integral show significant redshift evolution over a period of time which stretches from 1.25 to 4.5 Gyr after the big bang. This somewhat surprising conclusion may be an indication that the intergalactic medium was enriched in metals at redshifts much greater than 5, perhaps by the sources responsible for its reionization. Alternatively, the C IV systems we see may be associated with outflows from massive star-forming galaxies at later times, while the truly intergalactic metals may reside in regions of the Lyman alpha forest of lower density than those probed up to now.Comment: 24 pages including 5 figures. Accepted for publication in the Astrophysical Journal (September 10, 2003 issue

Probing the Ionization State of the Universe at z>6

We present high signal-to-noise ratio Keck ESI spectra of the two quasars known to have Gunn-Peterson absorption troughs, SDSS J1030+0524 (z=6.28) and SDSS J1148+5251 (z=6.37). The Ly alpha and Ly beta troughs for SDSS J1030+0524 are very black and show no evidence for any emission over a redshift interval of ~0.2 starting at z=6. On the other hand, SDSS J1148+5251 shows a number of emission peaks in the Ly beta Gunn-Peterson trough along with a single weak peak in the Ly alpha trough. The Ly alpha emission has corresponding Ly beta emission, suggesting that it is indeed a region of lower optical depth in the intergalactic medium at z=6.08. The stronger Ly beta peaks in the spectrum of SDSS J1148+5251 could conceivably also be the result of "leaks" in the IGM, but we suggest that they are instead Ly alpha emission from an intervening galaxy at z=4.9. This hypothesis gains credence from a strong complex of C IV absorption at the same redshift and from the detection of continuum emission in the Ly alpha trough at the expected brightness. If this proposal is correct, the quasar light has probably been magnified through gravitational lensing by the intervening galaxy. The Stromgren sphere observed in the absorption spectrum of SDSS J1148+5251 is significantly smaller than expected based on its brightness, which is consistent with the hypothesis that the quasar is lensed. If our argument for lensing is correct, the optical depths derived from the troughs of SDSS J1148+5251 are only lower limits (albeit still quite strong, with tau(LyA)>16 inferred from the Ly beta trough.) The Ly beta absorption trough of SDSS J1030+0524 gives the single best measurement of the IGM transmission at z>6, with an inferred optical depth tau(LyA)>22.Comment: To appear in July 2003 AJ, 34 pages, 11 figures; minor changes/typos fixe