We model the inspiral of a compact stellar-mass object into a massive non-rotating black hole including all dissipative and conservative first-order-in-the-mass-ratio effects on the orbital motion. The techniques we develop allow inspirals with initial eccentricities as high as e ∼ 0.8 and initial separations as large as p ∼ 50 to be evolved through many thousands of orbits up to the onset of the plunge into the black hole. The inspiral is computed using an osculating elements scheme driven by a hybridized self-force model, which combines Lorenz-gauge self-force results with highly accurate flux data from a Regge-Wheeler-Zerilli code. The high accuracy of our hybrid self-force model allows the orbital phase of the inspirals to be tracked to within ∼ 0.1 radians or better. The difference between self-force models and inspirals computed in the radiative approximation is quantified.
We present an algorithm for calculating the metric perturbations and gravitational self-force for extreme-mass-ratio inspirals (EMRIs) with eccentric orbits. The massive black hole is taken to be Schwarzschild and metric perturbations are computed in Lorenz gauge. The perturbation equations are solved as coupled systems of ordinary differential equations in the frequency domain. Accurate local behavior of the metric is attained through use of the method of extended homogeneous solutions and mode-sum regularization is used to find the self-force. We focus on calculating the self-force with sufficient accuracy to ensure its error contributions to the phase in a long term orbital evolution will be $\delta\Phi \lesssim 10^{-2}$ radians. This requires the orbit-averaged force to have fractional errors $\lesssim 10^{-8}$ and the oscillatory part of the self-force to have errors $\lesssim 10^{-3}$ (a level frequently easily exceeded). Our code meets this error requirement in the oscillatory part, extending the reach to EMRIs with eccentricities of $e \lesssim 0.8$, if augmented by use of fluxes for the orbit-averaged force, or to eccentricities of $e \lesssim 0.5$ when used as a stand-alone code. Further, we demonstrate accurate calculations up to orbital separations of $a \simeq 100 M$, beyond that required for EMRI models and useful for comparison with post-Newtonian theory. Our principal developments include (1) use of fully constrained field equations, (2) discovery of analytic solutions for even-parity static modes, (3) finding a pre-conditioning technique for outer homogeneous solutions, (4) adaptive use of quad-precision and (5) jump conditions to handle near-static modes, and (6) a hybrid scheme for high eccentricities
We calculate the evolution and gravitational-wave emission of a spinning compact object inspiraling into a substantially more massive (non-rotating) black hole. We extend our previous model for a non-spinning binary [Phys. Rev. D 93, 064024] to include the Mathisson-Papapetrou-Dixon spincurvature force. For spin-aligned binaries we calculate the dephasing of the inspiral and associated waveforms relative to models that do not include spin-curvature effects. We find this dephasing can be either positive or negative depending on the initial separation of the binary. For binaries in which the spin and orbital angular momentum are not parallel, the orbital plane precesses and we use a more general osculating element prescription to compute inspirals.
Porous silicon (PS) conductometric gas sensors are used to create a sensitivity matrix for the room temperature detection of NOx (NO, NO2). “P-type” nanopore coated microporous silicon is treated with tin, nickel, copper, and gold, electrolessly deposited onto the PS surface to form SnOx, NiO, CuxO, and AuxO nanostructured centers as confirmed by XPS measurements. The relative sensitivities of these modified PS gas sensor surface sites have been measured under 1–5 ppm NO exposure. An improved sensitivity of up to 10 times that of untreated PS is observed for a 1 ppm exposure. The choice of deposits is based on the hard to soft acid character of the nanostructured metal oxide islands that are fractionally deposited on the semiconductor interface and their effect on the physisorption of NO, a weak base, dictated by an inverse pattern (IHSAB) to the hard-soft acid base concept. NO, a free radical, can interact with oxygen sites on the modified PS sensor interfaces, to effect a transient NO2 signal unique to PS-based NO sensors, which is not observed as other basic analytes including NH3, PH3, H2S, SO2, and CO interact with “p-type” PS.A comparison is made between the current PS sensor systems which operate at room temperature and electrochemical and traditional metal oxide sensors.
We report development of a code to calculate the scalar self-force on a scalar-charged particle moving on generic bound orbits in the Kerr spacetime. The scalar self-force model allows rapid development of computational techniques relevant to generic gravitational extreme-mass-ratio inspirals (EMRIs). Our frequency-domain calculations are made with arbitrary numerical precision code written in Mathematica. We extend spectral source integration techniques to the Kerr spacetime, increasing computational efficiency. We model orbits with nearly arbitrary inclinations 0 ≤ ι < π/2 and eccentricities up to e 0.8. This effort extends earlier work by Warburton and Barack where motion was restricted to the equatorial plane or to inclined spherical orbits. Consistent with a recent discovery by Thornburg and Wardell [1] in time-domain calculations, we observe self-force oscillations during the radially-outbound portion of highly eccentric orbits around a rapidly rotating black hole. As noted previously, these oscillations reflect coupling into the self-force by quasinormal modes excited during pericenter passage. Our results confirm the effect with a frequency-domain code. More importantly, we find that quasinormal bursts (QNBs) appear directly in the waveform following each periastron passage. These faint bursts are shown to be a superposition of the leastdamped overtone (i.e., fundamental) of at least four (l = m ≤ 4) quasinormal modes. Our results suggest that QNBs should appear in gravitational waveforms, and thus provide a gauge-invariant signal. Potentially observable in high signal-to-noise ratio EMRIs, QNBs would provide high-frequency components to the parameter estimation problem that would complement low-frequency elements of the waveform.
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