2021 ngVLA Summer Short Talk Series


The next-generation Very Large Array Science Advisory Council (SAC) is organizing a cycle of weekly short online talks over the summer that focus on timely open science questions. Talks are scheduled to be 20-25 min, with another 15-20 min reserved for questions from the audience. 

The goal of the series is to draw a contingent of early-career researchers and students who are interested in open astronomy problems by facilitating discussions on topics that are particularly important and/or timely covering a broad range of astronomy research areas, while also drawing connections to a present or future facilities (e.g., ALMA, JWST, SKA, ngVLA, the ELTs, LSST/Rubin, or a proposed NASA observatory). 

The talks will be held online via Zoom Thursdays at 2 pm EDT and recorded/archived (along with the Q&A sessions) here for broader viewing.  We ask that you please use the link below to register for the entire series (it is free!) so that you receive all necessary Zoom connection information.  


Please Click Here to Register for the Webinar Series

Talk Schedule

Date Speaker Title Abstract/Video Recording
6/24/2021 Jonathan Tan (UVa / Chalmers University) Open Questions in Massive Star and Cluster Formation

Massive stars are powerful engines for driving the physical and chemical evolution of galaxies, while star clusters are the birth environments of most stars, including massive ones. It is thus important to study the origin of massive stars and clusters together as an integrated process. I briefly overview the many open questions that remain outstanding in this research field and highlight areas where ngVLA will be able to make important contributions.

7/01/2021 No Talk -- 4th of July Holiday
7/08/2021 Susanne Aalto (Chalmers University) Thick As Thieves! – What Is Hiding Inside the Most Compact and Obscured Galaxy Nuclei?

Cold gas plays a central role in feeding and regulating star formation and growth of supermassive black holes (SMBH) in galaxy nuclei. Particularly powerful activity occurs when interactions of gas-rich galaxies funnel large amounts of gas and dust into nuclei of luminous and ultra luminous infrared galaxies (LIRGs/ULIRGs). These dusty objects are of key importance to galaxy mass assembly over cosmic time and studying them is fundamental to our understanding of galaxy evolution. Recent studies reveal that some (U)LIRGS have very deeply embedded galaxy nuclei – hiding an unknown luminosity source: the Compact Obscured Nuclei (CONs). Our ALMA observations show that CONs are common in U/LIRGs – but what is lurking behind the masses of dust? A hidden phase of efficient black hole accretion – and/or an extremely compact burst of star formation? We need to go to long wavelengths to probe behind the veil of dust: mm/submm wavelengths with ALMA, cm wavelengths with VLA and the future ngVLA or SKA. We can also go to the far-infrared using space-based telescopes. I will present some initial ALMA high-resolution studies of the CON-LIRG IC860, the ex-CON lenticular NGC1377 – and demonstrate the power of high resolution and sensitivity in probing the enshrouded nuclei and their feedback. I will also show the first results from the ALMA CONquest survey and also how the VLA can reach behind the curtain of dust to undertake new studies of heretofore hidden, rapid evolutionary phases of galaxy nuclei. Do CONs represent a new, unknown evolutionary phase of nuclear growth?

7/15/2021 Jill Tarter (SETI)

When Is The Evidence Sufficient To Claim The Discovery of Extraterrestrial Life?


Organizing a press conference to tell the world about the detection of life beyond Earth, particularly a signal from a distant technological civilization, is a daunting prospect. How confident do you need to be before you pull that trigger? What are the consequences if you get it wrong? Dealing with that last question; we’ve already done that experiment. 2016 was a very good year for extraterrestrials, with multiple reports of detected ETIs. Those claims were all disputable, but doing the disputing consumed a huge fraction of time for everyone that the media identified as being part of the SETI community. The world did not stop as the result of these false positive claims, but the credibility of the claimants was diminished. For a scientific exploration that may take generations to bear fruit (if ever), and require continual funding, it is important to preserve credibility over time and be mindful of the circumstances that may yield only ambiguous results. Today the scientific community is pondering the reported detection of phosphine gas in the clouds of Venus, and debating whether this a valid biosignature; i.e. its production demands a biological component, as is the case for all sources we know on Earth. How do you design searches for technosignatures, some of which may be lacking in terrestrial exemplars, whose results will be credible? There are some practices we can employ.

7/22/2021 Paola Caselli (Max-Planck-Institute for Extraterrestrial Physics) From clouds to planets: the astrochemical link

All ingredients to make stars like our Sun and planets like our Earth are present in dense cold interstellar clouds. In these "stellar-system precursors" an active chemistry is already at work, as demonstrated by the presence of a rich variety of organic molecules in the gas phase and icy mantles encapsulating the sub-micrometer dust grains, the building blocks of planets. Here, I’ll present a journey from the earliest phases of star formation to protoplanetary disks, with links to our Solar System, highlighting the crucial role of astrochemistry as powerful diagnostic tool of the various steps present in the journey. The fundamental role of present and future facilities to make this connection possible will also be highlighted.

7/29/2021 Ryan Loomis (NRAO) Complex Chemistry During Planet Formation The chemical composition of nascent planets is set by the molecular inventories of the dust and gas rich protoplanetary disks in which they form. Understanding these environments is therefore crucial to predicting potential habitability, as well as uncovering the origin of Earth's organic reservoir. Recent gains in the sensitivity and resolution of (sub)mm observations have revolutionized our understanding of disk chemistry, enabling the detection of complex species and potential prebiotic precursors such as HC3N, CH3CN, CH3OH, and HCOOH. Major challenges remain, however, including how to connect ALMA observations of gas-phase disk organics with the bulk icy midplane reservoir responsible for comet and planet formation. Such extrapolations require both (1) complete disk molecular inventories and (2) detailed characterization of molecular abundance distributions. 

In this talk I discuss recent observational progress toward these two goals, highlighting results from the ALMA large program MAPS (Molecules At Planet-forming Scales). In particular, I focus on the role that lower frequency observations (ALMA Band 3 and below) are playing in rapidly advancing our understanding of complex chemistry in disks. Building on these results, I show how future observations with the ngVLA will play a critical role in unlocking the chemical composition of the disk midplane.
8/05/2021 Michael Kramer (Max-Planck-Institute for Radio Astronomy) Finding the Next Gravity Labs

New generations of telescopes offer the chance to discover and exploit new radio pulsars, either found in extreme binary systems or orbiting stellar and super-massive black holes. I will briefly summarise the current state of art and will present new results from searching and timing with the MeerKAT telescope as an SKA precursor. These include new discoveries as well as observations of relativistic binaries as probes of gravity, demonstrating the power of radio astronomy in providing unique and complementary insight into fundamental physics.

8/12/2021 Erik Rosolowsky (University of Alberta) Atomic Hydrogen at the Crossroads of Galaxy Evolution

Galaxy evolution is shaped by internal processes and environmental effects, and we hope to understand the galaxy population we see today through understanding this mix of processes. In this talk, I will show how the atomic gas in a galaxy connects and traces several different processes at work in galaxy evolution. In particular, I will present high resolution observations atomic gas in Local Group galaxies made with the Jansky Very Large Array. With these new three-dimensional spectral images, I will show how our research team is tracing the formation of star forming regions, measuring the inflow and outflow of gas from a galaxy, and characterizing turbulence in the interstellar medium. The amazing quality of these data is offering great insights about our nearest galactic neighbors, but with the ngVLA and the SKA we will be able to expand these studies across the galaxy population as a whole.

8/19/2021 Alex Tetarenko (East Asian Observatory's James Clerk Maxwell Telescope) Unraveling how black holes power explosive outflows with the time-domain

One of the key open questions in high energy astrophysics is understanding how black holes act as powerful cosmic engines, accreting large amounts of material and expelling matter in the form of relativistic jets. Time-domain observations now offer a promising new way to address this question. Through detecting and characterizing rapid flux variability in black hole systems across a wide range of frequency/energy bands, we can measure properties that are difficult, if not impossible, to measure by traditional spectral and imaging methods (e.g., size scales, geometry, jet speeds, the sequence of events leading to jet launching). While variability studies in the X-ray bands are a staple in the community, there are many challenges that accompany such studies at longer wavelengths. However, through utilizing the unique ability of the VLA to operate in sub-array mode, we can manufacture the data-sets we need to overcome these challenges. In this talk, I will discuss exciting new results from fast radio timing observations of several black hole X-ray binary sources. With this work, I will highlight how we can directly connect variability properties to internal jet physics, deriving fundamental jet properties from time-series signals alone. Additionally, I will discuss a new global observing program aimed at obtaining more of these invaluable fast timing data sets, and the key role that next-generation instruments (e.g., ngVLA, SKA, JWST) will play in driving new discoveries through this science.

8/26/2021 Eduardo Bañados (Max Planck Institute for Astronomy) Cancelled