The Hidden Nuclear Spectrum of the Luminous IRAS Source FSC10214++4724

Optical spectropolarimetry of the luminous IRAS source FSC10214$+$4724 (z$=2.286$) reveals that the strong (\twid17\%) linear polarization detected by Lawrence \etal\/ is shared by both the narrow UV emission lines and the underlying continuum. This observation and the brightness of the source rule out synchrotron emission and dichroic extinction by dust as the polarizing mechanism, leaving scattering as the only plausible cause of the polarized emission. The narrowness of the lines requires that the scatterers be dust grains or cool ($<1.6\times$10$^4$~K) electrons. We can recover the spectrum that is incident on the scattering medium provided we make some reasonable assumptions regarding the source geometry. The scattered UV spectrum has a power law index $\alpha$~ of $-1.2 \pm 0.6$ ($F_\nu\propto\nu^\alpha$), steeper than what would be expected from a young burst of star formation, but similar to many AGN.Comment: 10 pages, with figure, uuencoded postscript Institute for Advanced Study number AST 94/1

Discovery of a Magnetic DZ White Dwarf with Zeeman-Split Lines of Heavy Elements

A spectroscopic survey of previously-unstudied Luyten Half Second proper motion stars has resulted in the discoveries of two new cool magnetic white dwarfs. One (LHS 2273) is a routine DA star, T= 6,500K, with Zeeman-split H alpha and H beta, for which a simple model suggests a polar field strength of 18.5 MG viewed close to equator-on. However, the white dwarf LHS 2534 proves to be the first magnetic DZ showing Zeeman-split Na I and Mg I components, as well as Ca I and Ca II lines for which Zeeman components are blended. The Na I splittings result in a mean surface field strength estimate of 1.92 MG. Apart from the magnetic field, LHS 2534 is one of the most heavily-blanketed and coolest DZ white dwarfs at T ~ 6,000K.Comment: 7 pages, Astrophysical Journal (Letters), in pres

An Extraordinary Scattered Broad Emission Line in a Type 2 QSO

An infrared-selected, narrow-line QSO has been found to exhibit an extraordinarily broad Halpha emission line in polarized light. Both the extreme width (35,000 km/sec full-width at zero intensity) and 3,000 km/sec redshift of the line centroid with respect to the systemic velocity suggest emission in a deep gravitational potential. An extremely red polarized continuum and partial scattering of the narrow lines at a position angle common to the broad-line emission imply extensive obscuration, with few unimpeded lines of sight to the nucleus.Comment: 4 pages, 1 figure, to appear in the Astrophysical Journal Letter

The Polarized Spectrum of Apm 08279+5255

We report the discovery of significant linear polarization (p > 1%) in the hyperluminous z=3.87 BALQSO APM~08279+5255. The polarization spectrum is complex, with properties similar to those of other, lower redshift but more highly polarized BALQSOs. The resonance emission lines are unpolarized while the absorption troughs show polarization similar to or higher than the continuum. In particular, an apparent increase of polarization in the trough covering 1000-1030 angstroms (rest) supports the interpretation of this feature as a broad absorption component associated with OVI/Ly_beta local to the QSO, as opposed to an intervening damped Ly_alpha absorption system. The elevated polarization in some of the absorption features implies that we view the scattered (polarized) spectrum through a sightline with less absorbing material than the direct spectrum. Therefore, the complex structure of the polarization spectrum in this brilliant lensed BALQSO suggests that it will be an important laboratory for studying the structure of QSOs at high redshift.Comment: 8 pages, 1 figure. Accepted for publication in The Astrophysical Journal Letter

XMM-Newton and Optical Observations of Cataclysmic Variables from SDSS

We report on XMM-Newton and optical results for 6 cataclysmic variables that were selected from Sloan Digital Sky Survey spectra because they showed strong HeII emission lines, indicative of being candidates for containing white dwarfs with strong magnetic fields. While high X-ray background rates prevented optimum results, we are able to confirm SDSSJ233325.92+152222.1 as an intermediate polar from its strong pulse signature at 21 min and its obscured hard X-ray spectrum. Ground-based circular polarization and photometric observations were also able to confirm SDSSJ142256.31-022108.1 as a polar with a period near 4 hr. Photometry of SDSSJ083751.00+383012.5 and SDSSJ093214.82+495054.7 solidifies the orbital period of the former as 3.18 hrs and confirms the latter as a high inclination system with deep eclipses.Comment: 31 pages, 14 figures. Accepted for publication in the Astronomical Journa

Phase-resolved HST/STIS spectroscopy of the exposed white dwarf in the high-field polar AR UMa

Phase-resolved HST/STIS ultraviolet spectroscopy of the high-field polar AR UMa confirms that the WD photospheric Ly alpha Zeeman features are formed in a magnetic field of ~200 MG. In addition to the Ly alpha pi and sigma+ components, we detect the forbidden hydrogen 1s0->2s0 transition, which becomes ``enabled'' in the presence of both strong magnetic and electric fields. Our attempt in fitting the overall optical+UV low state spectrum with single temperature magnetic WD models remains rather unsatisfactory, indicating either a shortcoming in the present models or a new physical process acting in AR UMa. As a result, our estimate of the WD temperature remains somewhat uncertain, Twd=20000+-5000K. We detect a broad emission bump centered at ~1445A and present throughout the entire binary orbit, and a second bump near ~1650A, which appears only near the inferior conjunction of the secondary star. These are suggestive of low harmonic cyclotron emission produced by low-level (M-dot~1e-13 Msun/yr) accretion onto both magnetic poles. However, there is no evidence in the power spectrum of light variations for accretion in gas blobs. The observed Ly alpha emission line shows a strong phase dependence with maximum flux and redshift near orbital phase phi~0.3, strongly indicating an origin on the trailing hemisphere of the secondary star. An additional Ly alpha absorption feature with similar phasing as the Ly alpha emission, but a \~700km/s blueshift could tentatively be ascribed to absorption of WD emission in a moderately fast wind. We derive a column density of neutral hydrogen of NH=(1.1+-1.0)1e18 cm**-2, the lowest of any known polar.Comment: 26 pages, 10 figures, AAS TeX 5.0, accepted for publication in the Astrophysical Journa

A ballistic graphene superconducting microwave circuit

Josephson junctions (JJ) are a fundamental component of microwave quantum circuits, such as tunable cavities, qubits and parametric amplifiers. Recently developed encapsulated graphene JJs, with supercurrents extending over micron distance scales, have exciting potential applications as a new building block for quantum circuits. Despite this, the microwave performance of this technology has not been explored. Here, we demonstrate a microwave circuit based on a ballistic graphene JJ embedded in a superconducting cavity. We directly observe a gate-tunable Josephson inductance through the resonance frequency of the device and, using a detailed RF model, we extract this inductance quantitatively. We also observe the microwave losses of the device, and translate this into sub-gap resistances of the junction at {\mu}eV energy scales, not accessible in DC measurements. The microwave performance we observe here suggests that graphene Josephson junctions are a feasible platform for implementing coherent quantum circuits.Comment: 43 pages, 20 figure