List of Past Astronomy Colloquia : 01-Sep-2018 to 31-Dec-2018

Date:   Wednesday 12-Sep-2018
Speaker:   EDI Panel: Dr. Carrie Anderson (GSFC), Marcia Segura (UMD), and Dr. Amy Simon (GSFC)
Title:  Harassment, Bias, and Bullying in Astronomy and Planetary Science


The Astronomy Department Equity/Diversity/Inclusion committee presents the first colloquium of the semester - a panel discussion about harassment, bias, and bullying in science. Join Dr. Carrie Anderson (GSFC), Marcia Segura (UMD), and Dr. Amy Simon (GSFC), as they discuss their personal experiences over the course of their academic and professional careers. We will also discuss audience examples and questions and how these situations can be handled. Join the dialogue on Wednesday, September 12 at 3:30 pm (note the time change)


Dr. Anderson is a planetary astronomer at GSFC as a civil servant since 2009. Her research focuses on the remote sensing of planetary atmospheres. Dr. Anderson is currently involved in future mission and instrument concept studies including serving as the Deputy Principal Investigator (DPI) on a submillimeter hetero-dyne spectrometer, aimed at a mission proposal concept to Enceladus.

Ms. Segura is a principal faculty specialist with UMD. Her career in mission planning and operations has spanned 4 decades. She has been involved with three NASA flagship missions - Voyager. She has received the NASA award for Technical Excellence and NASA's Exceptional Public Service Medal for her efforts on the Galileo and Cassini missions.

Dr. Simon is a Senior Scientist studying planetary atmospheres at GSFC, where she's been a civil servant since 2001. She was an organizer of the 2003 and 2009 Women in Astronomy conferences and was a member of the AAS Committee on the Status of Women for 6 years.

Date:   Wednesday 19-Sep-2018
Speaker:   Dr. Lia Corrales (University of Wisconsin-Madison)
Title:  Are we star stuff? Solving mysteries of astromineralogy and dust grain growth with X-ray imaging and spectroscopy

The journey that interstellar metals take – from their nuclear reactive origins to their incorporation in planets, plants, and animals – is a highly uncertain one. The X-ray energy band is sensitive to absorption by all abundant metals in the interstellar medium (ISM), both in gas and dust form, enabling us to answer key questions in dust grain growth and processing. X-ray photoelectric absorption edges observed in high resolution spectra of Galactic X-ray binaries directly reveal the mineral composition of interstellar dust. X-ray imaging of dust scattering halos is an important tool for measuring dust grain sizes and their 3D spatial distribution. I will review open problems in the field of astromineralogy, including problems in reconciling X-ray absorption spectroscopy with ISM observations at other wavelengths. I will describe how X-ray missions in process for the near future — XRISM, ARCUS, and AXIS — will contribute. Finally, I will discuss multi-wavelength synergistic opportunities for obtaining the complete picture of dust grain evolution in the diffuse ISM.

Date:   Wednesday 26-Sep-2018
Speaker:   Dr. Sebastian Sanchez (Instituto de Astronomia Universidad Nacional Autonoma de Mexico)
Title:  The kiloparsec scale in galaxies: clues about their evolution

Galaxies were spatially resolved even before they were known to be galaxies. Despite this fact, we still study their evolution as if they were unresolved objects. The advent of large photometric and spectroscopic galaxy surveys (like 2dF,SDSS,GAMA), which supplied us with integrated or average properties of hundred of thousand or million of objects, have reinforced this approach to understand galaxy evolution. In more recent times, however, Integral Field Spectroscopy techniques opened a new window to the statistical exploration of galaxy properties, spatially resolved, at a kiloparsec scale.

I summarize here the sate-of-the-art of IFS galaxy surveys, highlighting some of their main results. In particular I will focus on the exploration of well-known scaling/evolutionary relations (such as the SK, SFMS and MZ-relations), which have their physical origin in the their kiloparsec-scale counterparts, and discuss their implications.

Date:   Wednesday 03-Oct-2018
Speaker:   Dr. Ashlee Wilkins (American Astronomical Society)
Title:  Science and Space Policy in the Current Era

As science educators, researchers, communicators, and/or supporters, we cannot deny the connection between science and government. The ability to send missions to Mars, to study star formation in a galaxy, and to model the early universe primarily depends on both government -- i.e., taxpayer -- money and public -- i.e., not just scientist -- support. Scientists can and do engage in work to determine the direction of our field and how society prioritizes science. As we approach the 2018 midterms, two years in to a new administration, how is science faring on a national stage? In this talk, I will discuss the current environment for science and space policy in general, and current events dominating policy discussions in the astronomical sciences in particular, including NASA flagship mission development, sexual harassment in the sciences, NSF facilities funding (and lack thereof), and how Congress has responded to the Trump administration's science priorities. I will discuss the role of the American Astronomical Society (AAS) in such discussions and in advocating for the astronomical sciences in Washington and what individual scientists can do to effectively engage in the political process.

Date:   Wednesday 10-Oct-2018
Speaker:   Dr. Keith Gendreau (NASA)
Title:  NICER Early Operations and Initial Results

The Neutron Star Interior Composition Explorer (NICER) was launched to the International Space Station (ISS) on June 3, 2017. NICER is a pointed X-ray timing and spectroscopy instrument that provides better than 100 nanosecond measurements of the arrival times of X-ray photons while providing moderate X-ray energy resolution in the 200-12000 eV energy range. The mission focus is to understand ultra-dense matter through X-ray timing of neutron stars. In addition, NICER has demonstrated autonomous pulsar based navigation for the first time. Initial operations on the ISS as well as early science and technology results will be discussed.

Date:   Wednesday 17-Oct-2018
Speaker:   Dr. Mark Voit (Michigan State University)
Title:  “Waterfalls or Rain: How does gas get into galaxies?”

Galaxies are commonly thought to acquire much of the gas that fuels star formation through streams of cold gas that flow along filaments of larger-scale structure: waterfalls. However, the universe's largest galaxies appear to have a different gas supply: precipitation of cold clouds out of hot circumgalactic gas via radiative cooling and condensation. I will present both observational and theoretical support for the precipitation model in large galaxies and show how it may apply to galaxies of all masses. One of the attractive features of the precipitation model is that it makes observationally testable predictions about the state of the circumgalactic medium, if most star-forming galaxies are indeed in a precipitating state.

Date:   Wednesday 24-Oct-2018
Speaker:   Dr. Armin Rest (STScI)
Title:  High-cadence Light Curves of Transients from the Kepler Telescope

Despite the expanding set of SNe discovered in recent surveys like PS1, ATLAS, PTF, and ASAS-SN, several fundamental questions remain of the nature of these explosions and their progenitor systems. The early light curves of SNe contain the critical information to understanding the nature of the progenitors and explosion physics: detonation, deflagration, and inwards-moving diffusion waves and much more. However, it has been difficult to obtain early light curve data with sufficient cadence and accuracy from the ground. With K2, and in the future TESS, we are now able to obtain high-cadence early light curves with exquisite photometric accuracy for thermonuclear and core-collapse SNe. I will discuss our growing and diverse sample of transients with high cadence light curves, ranging from SN Ia and IIPs to more exotic events like IIb's, fast transients, and TDEs.

Date:   Wednesday 31-Oct-2018
Speaker:   Dr. David Neufeld (JHU/UMD)
Title:  Dark matter that interacts with baryons: density distribution within the Earth, new constraints on the interaction cross-section, and a dark matter search currently under way in my basement

For dark matter (DM) particles with masses in the 0.6 - 6 proton mass range, we may set stringent constraints on the interaction cross-sections for scattering with ordinary baryonic matter. These constraints follow from the recognition that such particles can be captured by - and thermalized within - the Earth, leading to a substantial accumulation and concentration of DM that interact with baryons. I will discuss the probability that DM intercepted by the Earth will be captured, the number of DM particles thereby accumulated over Earth's lifetime, the fraction of such particles retained in the face of evaporation, and the density distribution of such particles within the Earth. This analysis provides an estimate of the DM particle density at Earth's surface, which may exceed 1.E+14 cm-3, and leads to constraints on various scattering cross-sections, which are placed by: (1) the lifetime of the relativistic proton beam at the Large Hadron Collider; (2) the orbital decay of spacecraft in low Earth orbit; (3) the vaporization rate of cryogenic liquids in well-insulated storage dewars; and (4) the thermal conductivity of Earth's crust. For the scattering cross-sections that were invoked recently in Barkana's original explanation for the anomalously deep 21 cm absorption reported by EDGES, DM particle masses in the 0.6 - 4 GeV/c^2 range are excluded. Finally, I will discuss a tabletop experiment (that we are currently conducting in my basement) to further constrain the interaction cross-sections for a variety of atomic nuclei.

Date:   Wednesday 07-Nov-2018
Speaker:   Dr. Jonathan Fortney (University of California Santa Cruz)
Title:  New Windows on Giant Planet Structure and Composition

In our current era of planetary physics we can use the astronomical perspective to look for trends in giant planet structure that can only be seen with a large sample size. We can also use detailed observations of Jupiter and Saturn, provided by Juno and Cassini, to test if long-held assumptions about giant planets really hold true. I will discuss several exoplanet topics including the giant planet mass-metallicity relation, connections with atmospheric abundances, and the radius anomaly of hot Jupiters. These works rest on a standard modeling framework for giant planet structure and evolution that can be tested in detail for Jupiter and Saturn. For Saturn specifically, I will show how Cassini inferences of the gravity field and internal oscillations probe the planet's interior structure in new ways.

Date:   Wednesday 14-Nov-2018
Speaker:   Dr. Yuri Levin (Flatiron Institute New York)
Title:  Fun with black holes.

Gravitational wave observations finally give us firm evidence that god is playing billiards with black holes. I will discuss a couple of interesting BH-related phenomena that one might look for in the GW sky. Firstly, I will discuss GW memory, which is potentially detectable by LISA (very likely), LIGO (if we are patient), and Pulsar Timing Arrays (if we and our descendants are patient). Secondly I will discuss vibrating nets of black holes connected by cosmic strings, physically interesting objects that may arise in the early Universe if both cosmic strings and primordial BHs are present. A possible third fun thing might also be discussed.

Date:   Wednesday 21-Nov-2018

Date:   Wednesday 28-Nov-2018
Speaker:   Dr. Ricardo Arevalo (UMD)
Title:  Technical and Scientific Prospects for in situ Planetary Exploration

The evolving priorities of the scientific community and the current White House Administration have put renewed focus on the search for biosignatures on potentially viable ocean worlds, and the exploration/exploitation of the lunar surface, respectively. In order to meet demanding science objectives within the limited resources of these near-term mission opportunities, the development of advanced technologies need needs to be accelerated. Here, I will introduce the analytical promise, instrument design, and development pathway for a laser-enabled Orbitrap mass spectrometer that will enable the comprehensive characterization of planetary materials derived from both ocean worlds and the lunar (sub)surface.

Date:   Wednesday 05-Dec-2018
Speaker:   NONE

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