Wine and Cheese Spring 2024

This page records the schedule, titles and abstracts of the JHU/STScI CAS Astrophysics Wine & Cheese Series in Fall 2022.

Wine and Cheese sessions with one speaker 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.

29 February

Michael Fall (JHU)

Galaxy Scaling Relations: What They Reveal About Galaxy Formation
Despite the apparent complexity of galaxies, some of their most basic properties (mass M, binding energy E, angular momentum J, etc) obey simple power-law scaling relations. Such relations provide a useful but generally under-exploited window into galaxy formation. This talk focuses on the relations between circular velocity V (a proxy for specific energy e = E/M) and mass M and between specific angular momentum j = J/M and mass M. The observed forms of these scaling relations for the stellar components of galaxies are closely related to those of their dark matter halos, which in turn are inherited from the primordial spectrum of cosmic density perturbations. This talk presents some new observations, new interpretations, and comparisons with recent cosmological hydrodynamical simulations of galaxy formation. The analysis presented here offers insights into the physical origins of several basic properties of galaxies, including their sizes, morphologies (disk vs spheroid) and feedback drivers (stars vs active galactic nuclei).

05 February

Robert Wilson (GSFC)

TRExS. Transits in the Roman galactic EXoplanet Survey
As one of its three Core Community Surveys, the Nancy Grace Roman Space Telescope (Roman, expected to launch in late 2026) will monitor 100s of millions of stars toward the center of the Milky Way, providing a powerful set of high-cadence, time-series data. Among the scientific investigations made possible by this dataset includes the detection of over 60,000 to 200,000 exoplanets via transit. The allure of this transiting exoplanet sample is threefold: First, in the statistical power offered by the order of magnitude increase in the number of known exoplanets, providing strict constraints on the demographics of intrinsically rare systems. Second, in the depth and distances of the surveyed stars, which represent nearly every major stellar population in the Galaxy. And third, in the near-infrared bandpass and color information which will enable the direct detection of 1000s of transiting exoplanet atmospheres and provide population-level constraints into their cloudiness and atmospheric circulation. In this talk, I will discuss Roman's scientific potential for transiting exoplanets, challenges in compiling the anticipated catalog of transiting exoplanet detections, and the actions that we in the TRExS collaboration are taking to harness Roman’s capabilities and enable a broad range of transiting exoplanet science in the Galactic Bulge.

K.D. Kuntz (JHU/GSFC)

The Line Emission Mapper (LEM): An X-ray Probe
The Line Emission Mapper (LEM) is a recently submitted Probe proposal for a large-grasp X-ray imaging spectrometer with a 30' FOV and an energy resolution of 0.9 eV at the center of the FOV, and <2 eV for the remainder of the FOV. With such resolution we will be able to do velocity mapping of SNR, galaxies, and clusters of galaxies, separate the WHIM emission from the Galactic halo emission using their velocities, and resolve the forest of lines in soft thermal spectra. LEM will open up vast new opportunities across astrophysics, from planetary physics to cosmology.

12 February

Andy Harris (UMd)

The Central Molecular Zone of the Galaxy in C+ from upGREAT/SOFIA
The Galactic center, deep at the bottom of the Galaxy's gravitational potential well, is a region of complex dynamics and regions of massive star formation. Observing it through the disk of the Galaxy, the pileup of emission from line-of-sight structures makes discrimination by excitation and velocity resolution essential. I will discuss fully-sampled spatial and velocity-resolved 158um [C II] SOFIA-upGREAT spectroscopic imaging of the center's 200pc wide Central Molecular Zone. These new data provide a high-resolution view that helps us understand center's structure, star formation, and gas flows into the Galactic center and onto the central black hole Sgr A*. They also serve as guides to interpreting far-infrared fine structure emission from other galactic nuclei. I will focus on two regions in the CMZ: Sgr A and B. Toward Sgr A, [C II] explores the possible interaction between the Sgr A(East) SNR and the Circum-nuclear Disk (CND) around the central black hole. At larger scales, the data provide insights into the origin of the Sgr A Thermal Arched Filaments. Toward Sgr B, [C II] imaging firmly establishes that the region extends as a coherent structure spanning some 34 pc along the Galactic plane. The extreme star formation cores of Sgr B2 contribute negligible amounts of [C II] intensity, a local example of the "C+ deficit" toward ULIRGs. The velocity structure across Sgr B constrains mechanisms for gas flow from the Galactic disk into the central regions. As a tracer of star formation in galactic nuclei, [C II] preferentially traces extended star formation rather than the most compact cores.

19 February

Kristen Garofoli (JHU/GSFC)

Tracing Feedback from X-ray Binaries Across Cosmic Time
Feedback from X-ray binaries is a key ingredient in regulating how reionization proceeded in the early Universe. I will provide an overview of the importance of feedback from X-ray binaries in star-forming environments, and summarize our current understanding of this component of feedback based on resolved population studies in nearby galaxies, recent measurements of the cosmic 21-cm signal, and binary population synthesis models. Finally, I will present prospects for future X-ray missions to directly trace the evolution of X-ray binary emission across key cosmic epochs, and discuss the importance of X-ray binaries to the ionizing photon budget in star-forming galaxies.

Pallavi Patil (JHU)

WISE-NVSS Selected Heavily Obscured, Jetted Quasars: Probing the Peak of Black Hole Growth at Cosmic Noon
Active Galactic Nuclei (AGN) feedback at z ~ 1-3 is believed to occur in the presence of thick columns of gas and dust, leading to heavily obscured systems that are challenging to detect at optical/X-rays but are transparent at radio and MIR wavelengths. By combining MIR and radio diagnostics, we have identified a sample of 155 ultra-luminous and obscured quasars (0.4 < z < 3) selected to have extremely red MIR colors in WISE and compact, bright radio emission in the NVSS/FIRST. In this talk, I will provide updates on our ongoing multiwavelength efforts to understand the nature of this unique sample in the context of jet-ISM feedback. High-resolution studies with VLA and VLBA confirm that most of the sample is compact with angular scales <0.2” (1.7 kpc at z~2). A radio spectral analysis reveals many sources show peaked/curved spectra consistent with being young radio AGN. A snapshot imaging survey with the VLBA at 5 GHz of 90 sample sources reveals a range of small jet structures and also unresolved sources. I will also discuss our follow-up study that includes deep multi-frequency VLA imaging and 870μm ALMA continuum and line (CO and HCN) observations, LBT imaging and spectroscopy, and NuSTAR data revealing a Compton-thick AGN. Overall, our sample is consistent with a population of recently triggered, young radio jets caught in a unique evolutionary stage in which they reside in a dense ISM. Finally, I discuss the implications of our study for understanding the impact of young jets on the ISM and star formation rates in powerful young AGNs.

26 February

Howard Hui (JPL)

SPHEREx: An all-sky near-infrared spectral survey
SPHEREx, an upcoming NASA medium-class Explorer Mission, will perform the first all-sky near infrared spectral survey. With a targeted launch date in early 2025, SPHEREx will map the entire sky at 6.2 arcsec from 0.75 to 5μm with a spectral resolution R>35 and 5σ sensitivity AB>19 over the nominal two-year mission. We will use this data set to 1) study the cosmic inflation by mapping the large-scale distribution of galaxies; 2) measure the light produced by stars and galaxies over cosmic history; and 3) determine the abundance of interstellar water and organic ices available to proto-planetary systems. In this talk, I will give a summary of the SPHEREx instrument design, survey plan and the expected data product, and highlight the potential science cases that can be done with this full-sky legacy archive available to the community.

4 March

Grecco Oyarzun Martinez (JHU)

The HI Gas Reservoirs of Galaxies at z~2
Neutral hydrogen gas (HI) is fundamental for galaxy formation. The accretion of HI gas from the intergalactic medium fuels star-formation, while the removal of HI gas explains why some galaxies quench. In this talk, I will focus on how we study the HI gas reservoirs around galaxies at z~2. First, I will discuss the major difficulty in carrying out these studies at this redshift: the faintness of HI gas in emission. Because of this limitation, to probe HI gas at z~2 we must instead turn to absorption signatures (DLAs) in the spectra of background quasars. Then, I will present a search for the galaxies associated with 14 DLAs at z~2 in Lyman-alpha emission. We detect a total of 6 Ly-alpha emitters, all of which are associated with intermediate metallicity DLAs (-1.5 < [M/H] < -0.3). This result hints that moderately enriched HI gas is typically associated with Lyman-alpha emitting, low stellar mass galaxies. Metal-rich DLAs, on the other hand, often feature massive galaxies that are bright in the sub-millimeter. This correspondence between the properties of galaxies and DLAs suggests that galaxies and HI gas reservoirs are already intertwined at z~2.

Kristen Garofoli (JHU/GSFC)

Tracing Feedback from X-ray Binaries Across Cosmic Time
Feedback from X-ray binaries is a key ingredient in regulating how reionization proceeded in the early Universe. I will provide an overview of the importance of feedback from X-ray binaries in star-forming environments, and summarize our current understanding of this component of feedback based on resolved population studies in nearby galaxies, recent measurements of the cosmic 21-cm signal, and binary population synthesis models. Finally, I will present prospects for future X-ray missions to directly trace the evolution of X-ray binary emission across key cosmic epochs, and discuss the importance of X-ray binaries to the ionizing photon budget in star-forming galaxies.

11 March

Lindsey Bleem (Argonne)

Cosmology Constraints from Cluster Abundances with Galaxy Clusters Discovered by the South Pole Telescope Over the past decade wide-area high-resolution cosmic microwave background (CMB) surveys conducted by the South Pole Telescope (SPT), Atacama Cosmology Telescope, and Planck have enabled the discovery of thousands of clusters via the Sunyaev-Zel'dovich (SZ) effect. The abundance of such clusters is a powerful cosmological probe as it depends sensitively upon both the expansion history of the universe and the growth of density fluctuations. In this talk I will overview recent progress in the field, particularly highlighting results from the SPT cluster cosmology program. This work, combining SPT-selected clusters with external galaxy lensing data from the Dark Energy Survey and Hubble Space Telescope, has led to tight constraints on LCDM cosmological model parameters. Looking to the future, SZ cluster cosmology will be significantly improved with data from the ongoing SPT-3G and future Simons Observatory and CMB-S4 experiments. These experiments, beyond identifying over an order of magnitude more clusters than previous generation projects, will also provide internal mass calibration for cluster samples via weak lensing of the CMB.

25 March

Ruth Daly (PSU)

The Outflow Method of Measuring Black Hole Spin with an Application to Sagittarius A*
The outflow method of measuring black hole spin will be described and applied to various source samples including supermassive and stellar-mass black holes. Excellent agreement is indicated by the comparison of spin values obtained with independent methods for individual black holes. Spin values allow a determination of the different mass components that comprise the total black hole mass. These components, including the rotational mass-energy, the irreducible mass-energy, and the spin mass-energy available for extraction from the black hole, will be described. The outflow method developed and presented by Daly (2019) to determine black hole spin functions, and the use of the spin function to study the mass components that comprise a black hole developed and presented by Daly (2022), will be applied to Sagittarius A* to determine the spin properties and mass components of this supermassive black hole, as described by Daly et al. (2024).

01 April

Miguel Zumalacarregui (AEI)

Lensing of Gravitational Waves: New Opportunities for Fundamental Physics
Just like light, gravitational waves (GWs) are deflected and magnified by massive objects in the Universe, a phenomenon known as gravitational lensing. In addition, their low frequency, phase coherence and lack of absorption make GWs complementary to lensed electromagnetic sources. Hence, in addition to well known effects (such as the formation of multiple images), lensed GWs allow for new wave-propagation phenomena like diffraction, the bending of the signal's wavefront. Lensing diffraction causes a frequency-dependent modulation of the signal, which encodes information about lens’ mass and distribution. I will describe the rich phenomenology of lensing diffraction, its observational prospects and its potential to probe the dark matter distribution.