Science Working Groups

by Davis Murphy last modified Sep 28, 2015 by Mark Adams

Working Group 1: The Cradle of Life

External chair: Andrea Isella (Rice University); Internal chairs: Arielle Moullet, Chat Hull (NRAO)

Topics:

(proto-)planetary systems and formation; cloud cores to stars; astrochemistry/biology; Solar System; SETI

The high resolution and sensitivity of the NGVLA in the 1-100 GHz frequency regime would pave the way for revolutionary new science in the fields of star and planet formation.  Major science drivers include (1) low-mass, embedded objects, where the longer wavelengths will allow us both to probe disk properties extremely close to the parent protostar and to reveal binaries and multiplicity out to much larger distances in our galaxy; (2) high-mass star formation, where the high sensitivity will allow us to resolve the density structure and dynamics of the youngest HII regions and high-mass protostellar jets; (3) protoplanetary disks, where the longer wavelengths and the unprecedented angular resolution will allow us to map planet forming regions around young stars and investigate the evolution of dust grains; (4) planetary science, where the unprecedented sensitivity will allow deep mapping of planetary atmosphere on very short time scales; and (5) SETI (the Search for ExtraterrestrialIntelligence), where the vast frequency and sky coverage of the NGVLA, coupled with improved targeting information from space missions such as GAIA and TESS, would bring the search for life outside of our own solar system into a new era.


Working Group 2: Galaxy Ecosystems (baryon cycle)

External chair: Eric Murphy (Caltech); Internal Chair: Adam Leroy (Ohio State)

Topics:

Galactic structure; interstellar medium and star formation; star formation laws, nearby galaxies; outflows and inflows; supermassive black holes (SMBHs)

The NGVLA would be a powerful tool to study the detailed astrophysics of star formation both within the Milky Way and nearby galaxies. With an unprecedented combination of high angular resolution and both line and continuum sensitivity, this revolutionary facility would: (1) provide new insight on the fundamental physics behind radio emission; (2) allow detailed spectroscopic characterization of the interstellar medium in all sorts of astronomical systems; (3) directly measure the ionizing photon rate of newly formed massive stars with the ability to penetrate through high columns of dust for extremely compact, embedded systems; (4) study dust physics by accessing the cold/massive dust component that powers the Raleigh-Jeans tail of dust spectral energy distributions; and (5) directly study the role of magnetic fields on the star formation process by increasingly pushing into the Faraday-thin regime where polarization observations should begin to probe deep into star forming regions.   The combination of sensitivity and astrometric accuracy promised by the NGVLA would further allow studies of the motions around black holes and at the base of jets, measurements of proper motions in Local Group galaxies, and refinements to our knowledge of Galactic structure.


Working Group 3: Galaxy Assembly through Cosmic Time (High z Universe)

External chair: Caitlin Casey (Texas);  Internal chairs: Mark Lacy (NRAO), Jackie Hodge (Leiden)

Topics:

cool gas and dust; dynamics; Active Galactic Nuclei (AGN)/SMBHs

The combination of unique capabilities offered by a Next-Generation VLA would enable great advances in studies of galaxy assemble over cosmic time. The sensitivity and frequency coverage would allow the detection of cool gas and dust in relatively 'normal' distant galaxies, including molecular gas tracers such as low-J CO, H20, HCN, and HCO+; synchrotron and free-free continuum emission; and even the exciting possibility of thermal emission at the highest (z~7) redshifts. The ultra-wide bandwidths would allow a complete sampling of radio/submillimeter SEDs, as well as the simultaneous detection of multiple emission lines. Finally, the superb angular resolution would move us beyond detection experiments and allow detailed studies of the morphology and dynamics of these systems, such as dynamical modeling of disks/mergers, determining the properties of outflows, measuring black hole masses from gas disks, and resolving multiple AGN nuclei. Our working group will explore the contribution of a NGVLA to these areas and more, as well as synergies with current and upcoming facilities including ALMA, SKA, TMT/ELT, and JWST.


Working Group 4: Time domain, Cosmology, Physics

External chair: Geoff Bower (ASIAA); Internal chair: Paul Demorest (NRAO)

Topics:

Transient sky; synoptic surveys; AGN physics; high energy phenomena; stellar phenomena; pulsars.

The NGVLA will provide powerful probes of the transient and high energy universe, revealing new physics.  Millisecond pulsars orbiting Sgr A* have the potential to measure black hole mass and spin to unprecedented accuracy, as well as probe the fundamentals of general relativity. Electromagnetic counterparts to gravitational wave events provide a window into extreme physics of neutron star mergers.  Tidal disruption of stars around massive black holes provides a unique laboratory for accretion-jet physics and explores the growth of black holes in galactic centers.  The physics of plasmas, from the Sun to galaxy clusters, are also uniquely probed by this instrument.

The same instrument is important for cosmological measurements.  Precision spectroscopy of molecular lines at high redshift can measure the evolution of fundamental constants, the change in redshift over time, the acceleration of objects relative to the cosmic flow, and the Hubble constant.