1803.05917
The Telltale Heartbeat: detection and characterization of eccentric orbiting planets via tides on their host star
Penoyre, Stone
Present an analytic description of tides raised on a star by a small orbiting body. In particular, highlight the disproportionate effect of eccentricity and thus the scope for using these tides to detect and characterize the orbits of exoplanets and brown dwarfs. The tidal distortions of the star produced by an eccentric orbit are, in comparison to a circular orbit, much richer in detail, and potentially visible from any viewing angle. The magnitude of these variations is much larger than that in a circular orbit of the same semi-major axis. These variations are visible in both photometric and spectroscopic data, and dominate other regular sources of phase variability (e.g. reflection and Doppler beaming) over a particularly interesting portion of parameter space. These tidal signatures will be a useful tool for planet detection on their own, and used in concert with other methods provide powerful constraints on planetary and stellar properties.
1803.05952
Observational constraints on the sub-galactic matter-power spectrum from galaxy-galaxy strong gravitational lensing
Bayer, et al
Constraining the sub-galactic matter-power spectrum in 1-10 kpc scales would make it possible to distinguish between the concordance LCDM model and various alternative DM models due to the significantly different levels of predicted mass structure. Here, demonstrate a novel approach to observationally constrain the population of overall low-mass density fluctuations in the inner regions of massive elliptical lens galaxies, based on the power spectrum of the associated surface-brightness perturbations observable in highly magnified galaxy-scale Einstein rings and gravitational arcs. The application of the method to the SLACS lens system SDSS J0252+0039 results in the following limits (at the 99% CL) on the dimensionless convergence-power spectrum (and the associated standard deviation in aperture mass): Delta^2_{delta kappa}< 1 (sigma_AM<0.8e8 Msun) on 0.5 kpc scale, Delta^2_{delta kappa}<0.1 (sigma_AM < 1e8 Msun) on 1kpc scale and Delta^2_{delta kappa}<0.01 (sigma_AM<3e8 Msun) on 3 kpc scale. The estimated effect of CDM sub-haloes lies considerably below these first observational upper-limit constraints on the level of inhomogeneities in the projected total mass distribution of galactic haloes. Future analysis for a larger sample of gg SL systems will narrow down these constraints and rule out all cosmological models predicting a significantly larger level of clumsiness on these critical sub-galactic scales.
The Telltale Heartbeat: detection and characterization of eccentric orbiting planets via tides on their host star
Penoyre, Stone
Present an analytic description of tides raised on a star by a small orbiting body. In particular, highlight the disproportionate effect of eccentricity and thus the scope for using these tides to detect and characterize the orbits of exoplanets and brown dwarfs. The tidal distortions of the star produced by an eccentric orbit are, in comparison to a circular orbit, much richer in detail, and potentially visible from any viewing angle. The magnitude of these variations is much larger than that in a circular orbit of the same semi-major axis. These variations are visible in both photometric and spectroscopic data, and dominate other regular sources of phase variability (e.g. reflection and Doppler beaming) over a particularly interesting portion of parameter space. These tidal signatures will be a useful tool for planet detection on their own, and used in concert with other methods provide powerful constraints on planetary and stellar properties.
1803.05952
Observational constraints on the sub-galactic matter-power spectrum from galaxy-galaxy strong gravitational lensing
Bayer, et al
Constraining the sub-galactic matter-power spectrum in 1-10 kpc scales would make it possible to distinguish between the concordance LCDM model and various alternative DM models due to the significantly different levels of predicted mass structure. Here, demonstrate a novel approach to observationally constrain the population of overall low-mass density fluctuations in the inner regions of massive elliptical lens galaxies, based on the power spectrum of the associated surface-brightness perturbations observable in highly magnified galaxy-scale Einstein rings and gravitational arcs. The application of the method to the SLACS lens system SDSS J0252+0039 results in the following limits (at the 99% CL) on the dimensionless convergence-power spectrum (and the associated standard deviation in aperture mass): Delta^2_{delta kappa}< 1 (sigma_AM<0.8e8 Msun) on 0.5 kpc scale, Delta^2_{delta kappa}<0.1 (sigma_AM < 1e8 Msun) on 1kpc scale and Delta^2_{delta kappa}<0.01 (sigma_AM<3e8 Msun) on 3 kpc scale. The estimated effect of CDM sub-haloes lies considerably below these first observational upper-limit constraints on the level of inhomogeneities in the projected total mass distribution of galactic haloes. Future analysis for a larger sample of gg SL systems will narrow down these constraints and rule out all cosmological models predicting a significantly larger level of clumsiness on these critical sub-galactic scales.
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