8 research outputs found
Massive Black Hole Binaries as LISA Precursors in the Roman High Latitude Time Domain Survey
With its capacity to observe faint active galactic nuclei
(AGN) out to redshift , Roman is poised to reveal a population of
black holes during an epoch of vigorous galaxy
assembly. By measuring the light curves of a subset of these AGN and looking
for periodicity, Roman can identify several hundred massive black hole binaries
(MBHBs) with 5-12 day orbital periods, which emit copious gravitational
radiation and will inevitably merge on timescales of years. During
the last few months of their merger, such binaries are observable with the
Laser Interferometer Space Antenna (LISA), a joint ESA/NASA gravitational wave
mission set to launch in the mid-2030s. Roman can thus find LISA precursors,
provide uniquely robust constraints on the LISA source population, help
identify the host galaxies of LISA mergers, and unlock the potential of
multi-messenger astrophysics with massive black hole binaries.Comment: White Paper for the Nancy Grace Roman Space Telescope's Core
Community Surveys (https://roman.gsfc.nasa.gov/science/ccs_white_papers.html
Where are the Water Worlds?: Self-Consistent Models of Water-Rich Exoplanet Atmospheres
It remains to be ascertained whether sub-Neptune exoplanets primarily possess
hydrogen-rich atmospheres or whether a population of HO-rich "water worlds"
lurks in their midst. Addressing this question requires improved modeling of
water-rich exoplanetary atmospheres, both to predict and interpret
spectroscopic observations and to serve as upper boundary conditions on
interior structure calculations. Here we present new models of
hydrogen-helium-water atmospheres with water abundances ranging from solar to
100% water vapor. We improve upon previous models of high water content
atmospheres by incorporating updated prescriptions for water self-broadening
and a non-ideal gas equation of state. Our model grid
(https://umd.box.com/v/water-worlds) includes temperature-pressure profiles in
radiative-convective equilibrium, along with their associated transmission and
thermal emission spectra. We find that our model updates primarily act at high
pressures, significantly impacting bottom-of-atmosphere temperatures, with
implications for the accuracy of interior structure calculations. Upper
atmosphere conditions and spectroscopic observables are less impacted by our
model updates, and we find that under most conditions, retrieval codes built
for hot Jupiters should also perform well on water-rich planets. We
additionally quantify the observational degeneracies among both thermal
emission and transmission spectra. We recover standard degeneracies with clouds
and mean molecular weight for transmission spectra, and we find thermal
emission spectra to be more readily distinguishable from one another in the
water-poor (i.e. near-solar) regime.Comment: Accepted for publication in ApJ. Full model grid is available at
https://umd.box.com/v/water-world
Massive Black Hole Binaries as LISA Precursors in the Roman High Latitude Time Domain Survey
International audienceWith its capacity to observe faint active galactic nuclei (AGN) out to redshift , Roman is poised to reveal a population of black holes during an epoch of vigorous galaxy assembly. By measuring the light curves of a subset of these AGN and looking for periodicity, Roman can identify several hundred massive black hole binaries (MBHBs) with 5-12 day orbital periods, which emit copious gravitational radiation and will inevitably merge on timescales of years. During the last few months of their merger, such binaries are observable with the Laser Interferometer Space Antenna (LISA), a joint ESA/NASA gravitational wave mission set to launch in the mid-2030s. Roman can thus find LISA precursors, provide uniquely robust constraints on the LISA source population, help identify the host galaxies of LISA mergers, and unlock the potential of multi-messenger astrophysics with massive black hole binaries
Massive Black Hole Binaries as LISA Precursors in the Roman High Latitude Time Domain Survey
International audienceWith its capacity to observe faint active galactic nuclei (AGN) out to redshift , Roman is poised to reveal a population of black holes during an epoch of vigorous galaxy assembly. By measuring the light curves of a subset of these AGN and looking for periodicity, Roman can identify several hundred massive black hole binaries (MBHBs) with 5-12 day orbital periods, which emit copious gravitational radiation and will inevitably merge on timescales of years. During the last few months of their merger, such binaries are observable with the Laser Interferometer Space Antenna (LISA), a joint ESA/NASA gravitational wave mission set to launch in the mid-2030s. Roman can thus find LISA precursors, provide uniquely robust constraints on the LISA source population, help identify the host galaxies of LISA mergers, and unlock the potential of multi-messenger astrophysics with massive black hole binaries
Massive Black Hole Binaries as LISA Precursors in the Roman High Latitude Time Domain Survey
International audienceWith its capacity to observe faint active galactic nuclei (AGN) out to redshift , Roman is poised to reveal a population of black holes during an epoch of vigorous galaxy assembly. By measuring the light curves of a subset of these AGN and looking for periodicity, Roman can identify several hundred massive black hole binaries (MBHBs) with 5-12 day orbital periods, which emit copious gravitational radiation and will inevitably merge on timescales of years. During the last few months of their merger, such binaries are observable with the Laser Interferometer Space Antenna (LISA), a joint ESA/NASA gravitational wave mission set to launch in the mid-2030s. Roman can thus find LISA precursors, provide uniquely robust constraints on the LISA source population, help identify the host galaxies of LISA mergers, and unlock the potential of multi-messenger astrophysics with massive black hole binaries
Massive Black Hole Binaries as LISA Precursors in the Roman High Latitude Time Domain Survey
International audienceWith its capacity to observe faint active galactic nuclei (AGN) out to redshift , Roman is poised to reveal a population of black holes during an epoch of vigorous galaxy assembly. By measuring the light curves of a subset of these AGN and looking for periodicity, Roman can identify several hundred massive black hole binaries (MBHBs) with 5-12 day orbital periods, which emit copious gravitational radiation and will inevitably merge on timescales of years. During the last few months of their merger, such binaries are observable with the Laser Interferometer Space Antenna (LISA), a joint ESA/NASA gravitational wave mission set to launch in the mid-2030s. Roman can thus find LISA precursors, provide uniquely robust constraints on the LISA source population, help identify the host galaxies of LISA mergers, and unlock the potential of multi-messenger astrophysics with massive black hole binaries
Massive Black Hole Binaries as LISA Precursors in the Roman High Latitude Time Domain Survey
International audienceWith its capacity to observe faint active galactic nuclei (AGN) out to redshift , Roman is poised to reveal a population of black holes during an epoch of vigorous galaxy assembly. By measuring the light curves of a subset of these AGN and looking for periodicity, Roman can identify several hundred massive black hole binaries (MBHBs) with 5-12 day orbital periods, which emit copious gravitational radiation and will inevitably merge on timescales of years. During the last few months of their merger, such binaries are observable with the Laser Interferometer Space Antenna (LISA), a joint ESA/NASA gravitational wave mission set to launch in the mid-2030s. Roman can thus find LISA precursors, provide uniquely robust constraints on the LISA source population, help identify the host galaxies of LISA mergers, and unlock the potential of multi-messenger astrophysics with massive black hole binaries