8 research outputs found
Jupiter Atmospheric Models and Outer Boundary Conditions for Giant Planet Evolutionary Calculations
We present updated atmospheric tables suitable for calculating the
post-formation evolution and cooling of Jupiter and Jupiter-like exoplanets.
These tables are generated using a 1D radiative transfer modeling code that
incorporates the latest opacities and realistic prescriptions for stellar
irradiation and ammonia clouds. To ensure the accuracy of our model parameters,
we calibrate them against the measured temperature structure and geometric
albedo spectrum of Jupiter, its effective temperature, and its inferred
internal temperature. As a test case, we calculate the cooling history of
Jupiter using an adiabatic and homogeneous interior and compare with extant
models now used to evolve Jupiter and the giant planets. We find that our model
reasonably matches Jupiter after evolving a hot-start initial condition to the
present age of the solar system, with a discrepancy in brightness
temperature/radius within two per cent. Our algorithm allows us to customize
for different cloud, irradiation, and metallicity parameters. This class of
boundary conditions can be used to study the evolution of solar-system giant
planets and exoplanets with more complicated interior structures and
non-adiabatic, inhomogeneous internal profiles.Comment: 11 pages, 5 figures. Accepted to Ap
Cosmological inference using gravitational wave standard sirens: A mock data analysis
International audienceThe observation of binary neutron star merger GW170817, along with its optical counterpart, provided the first constraint on the Hubble constant H0 using gravitational wave standard sirens. When no counterpart is identified, a galaxy catalog can be used to provide the necessary redshift information. However, the true host might not be contained in a catalog which is not complete out to the limit of gravitational-wave detectability. These electromagnetic and gravitational-wave selection effects must be accounted for. We describe and implement a method to estimate H0 using both the counterpart and the galaxy catalog standard siren methods. We perform a series of mock data analyses using binary neutron star mergers to confirm our ability to recover an unbiased estimate of H0. Our simulations used a simplified universe with no redshift uncertainties or galaxy clustering, but with different magnitude-limited catalogs and assumed host galaxy properties, to test our treatment of both selection effects. We explore how the incompleteness of catalogs affects the final measurement of H0, as well as the effect of weighting each galaxyâs likelihood of being a host by its luminosity. In our most realistic simulation, where the simulated catalog is about three times denser than the density of galaxies in the local universe, we find that a 4.4% measurement precision can be reached using galaxy catalogs with 50% completeness and âŒ250 binary neutron star detections with sensitivity similar to that of Advanced LIGOâs second observing run
Cosmological Inference using Gravitational Wave Standard Sirens: A Mock Data Challenge
The observation of binary neutron star merger GW170817, along with its optical counterpart, provided the first constraint on the Hubble constant using gravitational wave standard sirens. When no counterpart is identified, a galaxy catalog can be used to provide complementary redshift information. However, the true host might not be contained in a catalog which is not complete out to the limit of gravitational-wave detectability. These electromagnetic and gravitational-wave selection effects must be accounted for. We describe and implement a method to estimate using both the counterpart and the galaxy catalog standard siren methods. We perform a series of mock data challenges using binary neutron star mergers to confirm our ability to recover an unbiased estimate of . Our simulations used a simplified universe with no redshift uncertainties or galaxy clustering, but with different magnitude-limited catalogs and assumed host galaxy properties, to test our treatment of both selection effects. We explore how the incompleteness of catalogs affects the final measurement of , as well as the effect of weighting each galaxy's likelihood of being a host by its luminosity. In our most realistic simulation, where the simulated catalog is about three times denser than the density of galaxies in the local universe, we find that a 4.4\% measurement precision can be reached using galaxy catalogs with 50\% completeness and 249 binary neutron star detections with sensitivity similar to that of Advanced LIGO's second observing run
Model comparison from LIGOâVirgo data on GW170817âs binary components and consequences for the merger remnant
International audienceGW170817 is the very first observation of gravitational waves originating from the coalescence of two compact objects in the mass range of neutron stars, accompanied by electromagnetic counterparts, and offers an opportunity to directly probe the internal structure of neutron stars. We perform Bayesian model selection on a wide range of theoretical predictions for the neutron star equation of state. For the binary neutron star hypothesis, we find that we cannot rule out the majority of theoretical models considered. In addition, the gravitational-wave data alone does not rule out the possibility that one or both objects were low-mass black holes. We discuss the possible outcomes in the case of a binary neutron star merger, finding that all scenarios from prompt collapse to long-lived or even stable remnants are possible. For long-lived remnants, we place an upper limit of 1.9âkHz on the rotation rate. If a black hole was formed any time after merger and the coalescing stars were slowly rotating, then the maximum baryonic mass of non-rotating neutron stars is at most , and three equations of state considered here can be ruled out. We obtain a tighter limit of for the case that the merger results in a hypermassive neutron star
Open data from the first and second observing runs of Advanced LIGO and Advanced Virgo
Advanced LIGO and Advanced Virgo are monitoring the sky and collecting gravitational-wave strain data with sufficient sensitivity to detect signals routinely. In this paper we describe the data recorded by these instruments during their first and second observing runs. The main data products are gravitational-wave strain time series sampled at 16384 Hz. The datasets that include this strain measurement can be freely accessed through the Gravitational Wave Open Science Center at http://gw-openscience.org, together with data-quality information essential for the analysis of LIGO and Virgo data, documentation, tutorials, and supporting software
Search for intermediate-mass black hole binaries in the third observing run of Advanced LIGO and Advanced Virgo
International audienceIntermediate-mass black holes (IMBHs) span the approximate mass range 100â105âMâ, between black holes (BHs) that formed by stellar collapse and the supermassive BHs at the centers of galaxies. Mergers of IMBH binaries are the most energetic gravitational-wave sources accessible by the terrestrial detector network. Searches of the first two observing runs of Advanced LIGO and Advanced Virgo did not yield any significant IMBH binary signals. In the third observing run (O3), the increased network sensitivity enabled the detection of GW190521, a signal consistent with a binary merger of mass âŒ150âMâ providing direct evidence of IMBH formation. Here, we report on a dedicated search of O3 data for further IMBH binary mergers, combining both modeled (matched filter) and model-independent search methods. We find some marginal candidates, but none are sufficiently significant to indicate detection of further IMBH mergers. We quantify the sensitivity of the individual search methods and of the combined search using a suite of IMBH binary signals obtained via numerical relativity, including the effects of spins misaligned with the binary orbital axis, and present the resulting upper limits on astrophysical merger rates. Our most stringent limit is for equal mass and aligned spin BH binary of total mass 200âMâ and effective aligned spin 0.8 at 0.056 Gpcâ3 yrâ1 (90% confidence), a factor of 3.5 more constraining than previous LIGO-Virgo limits. We also update the estimated rate of mergers similar to GW190521 to 0.08 Gpcâ3 yrâ1.Key words: gravitational waves / stars: black holes / black hole physicsCorresponding author: W. Del Pozzo, e-mail: [email protected]â Deceased, August 2020