Wine and Cheese Spring 2020: Difference between revisions
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=17 February= | =17 February= | ||
==Duncan Watts (JHU)== | ==Duncan Watts (JHU)== | ||
''' ''' | '''Beyond Optical Depth: Future Determination of Ionization History from the CMB''' | ||
Cosmic microwave background (CMB) photons are partially polarized, both by free electrons around recombination, and by free electrons from reionization. The free electron fraction as a function of redshift directly affects the observed large-scale polarized CMB, by changing both the amplitude and the shape of the E-mode power spectrum. Planck and WMAP have constrained the reionization optical depth, but this integrated quantity can only constrain the redshift of reionization assuming the intergalactic medium (IGM) instantaneously transitions from neutral to ionized. In this talk, I will demonstrate that future CMB measurements with a near cosmic variance-limited E-mode measurement will be able to distinguish between different models of reionization that have not yet been ruled out by direct measurements of the ionization state of the IGM. Specifically, I will consider a simple model with a period of an early ionization fraction of 5% at z~28 in addition to the standard reionization scenario. I will also demonstrate that a cosmic variance measurement requires a moderate sensitivity of 10 μK arcmin, and will be achieved by the CLASS experiment. | |||
== Mihoko Yukita (GSFC) == | == Mihoko Yukita (GSFC) == | ||
'''The Hard X-ray View of Nearby Galaxies with NuSTAR''' | '''The Hard X-ray View of Nearby Galaxies with NuSTAR''' | ||
NuSTAR is the world's first focusing hard X-ray telescope, allowing unprecedented access to the sky above 10 keV. Thanks to its sensitivity and spatial resolution, we are now able to resolve individual X-ray binaries in nearby galaxies and study their populations. X-ray binaries had traditionally been classified via their companion stars, e.g. high-mass or low-mass counterparts. With NuSTAR, we can identify them by their compact objects as black holes or neutron stars and study their accretion states in detail. We have now amassed enough information on X-ray binaries in nearby galaxies with NuSTAR to compare the compact object population to properties of their host galaxies including their mass, star-formation activity, and morphology. | NuSTAR is the world's first focusing hard X-ray telescope, allowing unprecedented access to the sky above 10 keV. Thanks to its sensitivity and spatial resolution, we are now able to resolve individual X-ray binaries in nearby galaxies and study their populations. X-ray binaries had traditionally been classified via their companion stars, e.g. high-mass or low-mass counterparts. With NuSTAR, we can identify them by their compact objects as black holes or neutron stars and study their accretion states in detail. We have now amassed enough information on X-ray binaries in nearby galaxies with NuSTAR to compare the compact object population to properties of their host galaxies including their mass, star-formation activity, and morphology. |
Revision as of 00:56, 14 February 2020
This page records the schedule, titles and abstracts of the JHU/STScI CAS Astrophysics Wine & Cheese Series in Spring 2020.
Wine and Cheese sessions with one talk will have a 50 minute talk with 10 minutes for questions. Sessions with two speakers will have two 25 minute talks, each with 5 minutes for questions. Sessions in the Graduate Student Series will have three 15 minute talks, each with 5 minutes for questions.
Back to W&C Schedule
3 February
Brice Menard (JHU)
Deprojecting Astronomical Sky Maps
We see the sky in 2D but, in order to conduct astrophysical studies, we need 3D information. I will show how to take any large-scale map of the sky, at any wavelength, and extract 3D extragalactic information from it using clustering measurements. I will then apply this technique to observations of galaxies and diffuse components across the electromagnetic spectrum.
10 February
Alberto Bolatto (UMd)
Synergies Between IFU and Molecular Gas Surveys The internal structure of galaxies harbors important clues of the processes that shape their evolution. The last several years have seen the completion of a number of galaxy surveys using Integral Field Units that produce complete spectroscopic mapping at optical wavelengths (MaNGA, CALIFA, SAMI). Those data have produced invaluable information about the stellar and ionized gas components of galaxies. Information about the neutral and molecular phases of the gas, the largest gas reservoirs, has however historically lagged behind. I will present some results from EDGE-CALIFA, a follow up of 126 CALIFA galaxies in CO emission that is currently starting to be expanded with ALMA, and I will discuss future prospects with existing and planned instruments, in particular the ngVLA (a proposal to the Astro2020 Decadal).
17 February
Duncan Watts (JHU)
Beyond Optical Depth: Future Determination of Ionization History from the CMB Cosmic microwave background (CMB) photons are partially polarized, both by free electrons around recombination, and by free electrons from reionization. The free electron fraction as a function of redshift directly affects the observed large-scale polarized CMB, by changing both the amplitude and the shape of the E-mode power spectrum. Planck and WMAP have constrained the reionization optical depth, but this integrated quantity can only constrain the redshift of reionization assuming the intergalactic medium (IGM) instantaneously transitions from neutral to ionized. In this talk, I will demonstrate that future CMB measurements with a near cosmic variance-limited E-mode measurement will be able to distinguish between different models of reionization that have not yet been ruled out by direct measurements of the ionization state of the IGM. Specifically, I will consider a simple model with a period of an early ionization fraction of 5% at z~28 in addition to the standard reionization scenario. I will also demonstrate that a cosmic variance measurement requires a moderate sensitivity of 10 μK arcmin, and will be achieved by the CLASS experiment.
Mihoko Yukita (GSFC)
The Hard X-ray View of Nearby Galaxies with NuSTAR NuSTAR is the world's first focusing hard X-ray telescope, allowing unprecedented access to the sky above 10 keV. Thanks to its sensitivity and spatial resolution, we are now able to resolve individual X-ray binaries in nearby galaxies and study their populations. X-ray binaries had traditionally been classified via their companion stars, e.g. high-mass or low-mass counterparts. With NuSTAR, we can identify them by their compact objects as black holes or neutron stars and study their accretion states in detail. We have now amassed enough information on X-ray binaries in nearby galaxies with NuSTAR to compare the compact object population to properties of their host galaxies including their mass, star-formation activity, and morphology.