Multifrequency VLBI Observations of the Broad Absorption Line Quasar J1020+4320: Recently Restarted Jet Activity?

This paper reports very-long-baseline interferometry observations of the radio-loud broad absorption line (BAL) quasar J1020+4320 at 1.7, 2.3, 6.7, and 8.4 GHz using the Japanese VLBI network (JVN) and European VLBI network (EVN). The radio morphology is compact with a size of ~10 pc. The convex radio spectrum is stable over the last decade; an observed peak frequency of 3.2 GHz is equivalent to 9.5 GHz in the rest frame, suggesting an age of the order of ~100 years as a radio source, according to an observed correlation between linear size and peak frequency of compact steep spectrum (CSS) and giga-hertz peaked spectrum (GPS) radio sources. A low-frequency radio excess suggests relic of past jet activity. J1020+4320 may be one of the quasars with recurrent and short-lived jet activity during a BAL-outflowing phase.Comment: 7 pages, 2 figures, 2 tables, accepted for publication in PAS

The Structure of Pre-transitional Protoplanetary Disks I: Radiative Transfer Modeling of the Disk+Cavity in the PDS 70 system

Through detailed radiative transfer modeling, we present a disk+cavity model to simultaneously explain both the SED and Subaru H-band polarized light imaging for the pre-transitional protoplanetary disk PDS 70. Particularly, we are able to match not only the radial dependence, but also the absolute scale, of the surface brightness of the scattered light. Our disk model has a cavity 65 AU in radius, which is heavily depleted of sub-micron-sized dust grains, and a small residual inner disk which produces a weak but still optically thick NIR excess in the SED. To explain the contrast of the cavity edge in the Subaru image, a factor of ~1000 depletion for the sub-micron-sized dust inside the cavity is required. The total dust mass of the disk may be on the order of 1e-4 M_sun, only weakly constrained due to the lack of long wavelength observations and the uncertainties in the dust model. The scale height of the sub-micron-sized dust is ~6 AU at the cavity edge, and the cavity wall is optically thick in the vertical direction at H-band. PDS 70 is not a member of the class of (pre-)transitional disks identified by Dong et al. (2012), whose members only show evidence of the cavity in the millimeter-sized dust but not the sub-micron-sized dust in resolved images. The two classes of (pre-)transitional disks may form through different mechanisms, or they may just be at different evolution stages in the disk clearing process.Comment: 28 pages (single column), 7 figures, 1 table, ApJ accepte

NuSTAR and swift observations of the fast rotating magnetized white dwarf AE Aquarii

AE Aquarii is a cataclysmic variable with the fastest known rotating magnetized white dwarf (P_(spin) = 33.08 s). Compared to many intermediate polars, AE Aquarii shows a soft X-ray spectrum with a very low luminosity (L X ~ 10^(31) erg s^(–1)). We have analyzed overlapping observations of this system with the NuSTAR and the Swift X-ray observatories in 2012 September. We find the 0.5-30 keV spectra to be well fitted by either an optically thin thermal plasma model with three temperatures of 0.75^(+0.18)_(-0.45), 2.29^(+0.96)_(-0.82), and 9.33^(+6.07)_(-2.18) keV, or an optically thin thermal plasma model with two temperatures of 1.00^(+0.34)_(-0.23) and 4.64^(+1.58)_(-0.84) keV plus a power-law component with photon index of 2.50^(+0.17)_(-0.23). The pulse profile in the 3-20 keV band is broad and approximately sinusoidal, with a pulsed fraction of 16.6% ± 2.3%. We do not find any evidence for a previously reported sharp feature in the pulse profile

In-flight Calibration of Hitomi Soft X-ray Spectrometer (3) Effective Area

We present the result of the in-flight calibration of the effective area of the Soft X-ray Spectrometer (SXS) onboard the Hitomi X-ray satellite using an observation of the Crab nebula. We corrected for the artifacts when observing high count rate sources with the X-ray microcalorimeter. We then constructed a spectrum in the 0.5-20 keV band, which we modeled with a single power-law continuum attenuated by an interstellar extinction. We evaluated the systematic uncertainty upon the spectral parameters by various calibration items. In the 2-12 keV band, the SXS result is consistent with the literature values in flux (2.20 $\pm$ 0.08) $\times$10$^{-8}$ erg s$^{-1}$ cm$^{-2}$ with a 1$\sigma$ statistical uncertainty) but is softer in the power-law index (2.19 $\pm$ 0.11). The discrepancy is attributable to the systematic uncertainty of about $+$6/$-$7% and $+$2/$-$5% respectively for the flux and the power-law index. The softer spectrum is affected primarily by the systematic uncertainty of the Dewar gate valve transmission and the event screening.Comment: 13 pages, 7 figures.PASJ accepte

Adaptive Optics Spectroscopy of the [Fe II] Outflows from HL Tauri and RW Aurigae

We present new results of [Fe II] 1.644-micron spectroscopy toward the jets from HL Tau and RW Aur carried out with the Subaru Telescope combined with the adaptive optics system. We observed the regions within 2" - 3" from the stars with the sub-arcsecond resolutions of 0."5 and 0."2 for HL Tau and RW Aur, respectively. In addition to the strong, high velocity emission extended along each jet, we detected a blueshifted low velocity emission feature seen as a wing or shoulder of the high velocity emission at each stellar position. Detailed analysis shows that the position-velocity diagrams (PVDs) of HL Tau and RW Aur show a characteristic similar to those of the cold disk wind and X-wind models in that the [Fe II] line width is broad in the vicinity of the stellar position and is narrower at the extended jet. A closer comparison suggests, however, that the disk wind model tends to have too large line width at the jet while the X-wind model has excess emission on the redshifted side at the stellar position. The narrow velocity width with symmetric line profiles of the observed high velocity emission supports an X-wind type model where the launching region is localized in a small radial range, while the low velocity emission located away from the star favors the presence of a disk wind. The [Fe II] emission from the HL Tau jet shows a gap of 0."8 between the redshifted jet and the star, indicating the presence of an optically thick disk of ~ 160 AU in radius. The [Fe II] emission from the RW Aur jet shows a marked drop from the redshifted peak at Y ~ -0."2 toward the star, suggesting that its disk radius is smaller than 40 AU.Comment: Accepted in the ApJ (October 2006, v649n2), AAS LaTEX macros v 5.2, Total 25 pages with 7 figure

A Young Brown Dwarf Companion to DH Tauri

We present the detection of a young brown dwarf companion DH Tau B associated with the classical T Tauri star DH Tau. Near-infrared coronagraphic observations with CIAO on the Subaru Telescope have revealed DH Tau B with H = \~15 mag located at 2.3" (330 AU) away from the primary DH Tau A. Comparing its position with a Hubble Space Telescope archive image, we confirmed that DH Tau A and B share the common proper motion, suggesting that they are physically associated with each other. The near-infrared color of DH Tau B is consistent with those of young stellar objects. The near-infrared spectra of DH Tau B show deep water absorption bands, a strong K I absorption line, and a moderate Na I absorption line. We derived its effective temperature and surface gravity of Teff = 2700 -- 2800 K and log g = 4.0--4.5, respectively, by comparing the observed spectra with synthesized spectra of low-mass objects. The location of DH Tau B on the HR diagram gives its mass of 30 -- 50 M_Jupiter.Comment: 10 pages, 14 figures, 1 table, accepted for publication in Ap

Significance of antiprothrombin antibodies in patients with systemic lupus erythematosus: clinical evaluation of the antiprothrombin assay and the antiphosphatidylserine/prothrombin assay, and comparison with other antiphospholipid antibody assays

Antibodies against prothrombin are detected by enzyme immunoassays (EIA) in sera of patients with antiphospholipid syndrome (APS). However, there are two methods for antiprothrombin EIA; one that uses high binding plates (aPT-A), and another that utilizes phosphatidylserine bound plates (aPS/PT). We aimed to evaluate and compare aPT-A and aPS/PT in a clinical setting. We performed EIA for anti-PT, anti-PS/PT, IgG, and IgM anticardiolipin antibodies (aCL), and IgG β2-glycoprotein I-dependent aCL (aβ2GPI/CL) with serum samples from 139 systemic lupus erythematosus (SLE) patients (16 with history of at least one thrombotic episode) and 148 controls. We observed that: (1) although titers of anti-PT and anti-PS/PT were significantly related with each other (P < 0.0001, ρ = 0.548), titer of anti-PT and anti-PS/PT differed greatly in some samples; (2) odds ratio and 95% confidence interval for each assay was 3.556 (1.221–10.355) for aPT-A, 4.591 (1.555–15.560) for aPS/PT, 4.204 (1.250–14.148) for IgG aCL, 1.809 (0.354–9.232) for IgM aCL, and 7.246 (2.391–21.966) for aβ2GPI/CL. We conclude that, while all EIA performed in this study except IgM aCL are of potential value in assessing the risk of thrombosis, aPS/PT and aβ2GPI/CL seemed to be highly valuable in clinical practice, and that autoantibodies detected by anti-PT and anti-PS/PT are not completely identical