VLA & VLBA News

Mark McKinnon (Assistant Director, New Mexico Operations)

On 13 March, the NRAO announced the closure of its facilities in New Mexico, Virginia, and West Virginia in response to school closures in those states due to concerns over the COVID-19 coronavirus. Despite the NRAO facility (i.e. building) closures, science observations with the Jansky Very Large Array (VLA) and the Very Long Baseline Array (VLBA) continue.

A small crew, such as telescope operators and VLBA site technicians, support observing as usual, while the remainder of the New Mexico staff work from home. They are accessible via email and endeavor to provide their telescope and user support services remotely. Scientific and technical staff are also on call, primarily during daylight hours, to troubleshoot and repair any critical failures that may occur. Due to these remote support arrangements, telescope reliability and observing efficiency may decline in the near future. We appreciate our users understanding and support of our health initiatives as we continue to support science observations with the VLA and VLBA.

Visit the VLA and VLBA websites for the latest information on their current operational status.

Upcoming Sched Release & VLBA Correlator Model Update

Walter Brisken

The "Sched" program, which is used to produce observing schedules for the Very Long Baseline Array (VLBA), the High Sensitivity Array, and many other Very Long Baseline Interferometry (VLBI) observing systems around the world, will have a new release, version 11.6, very shortly.

This release comes without any significant changes to the actual software. Its main changes are updates to catalogs and setup files. The bundled source catalog has been updated based on the third International Celestial Reference Frame (ICRF3) solutions with flux densities provided by the Radio Fundamental Catalog (RFC). The coordinates of many antennas, including those of all VLBA antennas, have been updated to improved values based on the recent GSFC 2019d Geodetic Solution. The changes in positions, compared to the previous catalog, for VLBA stations, are at the 1-2 cm level. New setup files have been introduced that implement new 4 Gbps recording modes. The vlbi@nrao.edu email list will announce the availability of the new release.

The VLBA correlator will switch to correlation using Goddard's CALC version 11 delay model for projects scheduled with the new Sched release. Support for the previous delay model, CALC 9.1, will be discontinued at a date to be determined in the future, but at least one year from now. A comparison of CALC 9.1 and CALC 11 was performed and documented in VLBA Sensitivity Upgrade (VSU) memo 45. Users in the middle of long-term astrometric observing programs should continue to use Sched 11.5 to ensure continuity of the delay model. All new projects should switch to using Sched 11.6 as soon as possible.

Projects requesting the current software versions (Sched 11.5 and CALC 9.1) should add a line to their *.key file similar to:
       note1 = 'Please schedule with Sched 11.5'

This will ensure the new version of Sched is not run. The choice of CALC version will be made automatically based on the sched version used.

References:
ICRF3, RFC, VSU memo 45

ngVLA Project News

Eric Murphy

Compact Objects and Energetic Phenomena in the Multi-Messenger Era

On 14-16 July 2020, the NRAO and the ngVLA Project tentatively plan to convene a science conference titled Compact Objects and Energetic Phenomena in the Multi-Messenger Era in Saint Paul, MN, USA. The deadline to submit oral abstracts and requests for travel support is 10 April. The conference organizers are monitoring the COVID-19 situation and will promptly notify the community if it is decided to postpone the conference.

Dr. Anne Kinney, head of the National Science Foundation’s Directorate for Mathematical and Physical Sciences, will give a keynote talk to open the conference. Kinney is responsible for determining how the Directorate pursues NSF’s 10 Big Ideas for future investment. One of the Big Ideas, Windows on the Universe, is focused on maturing the nascent field of multi-messenger astrophysics. Nature Astronomy has commissioned a conference report and will be sponsoring a prize competition for poster presentations.

Young Radio AGN in the ngVLA Era

Pallavi Patil (University of Virginia) & Kristina Nyland (National Research Council, U.S. Naval Research Laboratory)

VLBA continuum images of young, compact radio AGN with extents of tens of parsecs. The high sensitivity and angular resolution of the ngVLA will facilitate deep, spatially-resolved surveys of compact radio jets with comparable extents in a wide range of systems, providing new insights into the energetic impact of young radio jets under a variety of host galaxy conditions and properties.

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Young, compact radio sources associated with accreting supermassive black holes represent a poorly understood phase in the life cycles of jetted active galactic nuclei (AGN). These objects have (re)ignited their central engines within the past 100-10,000 years, resulting in sub-galactic jet extents of ~ 10 parsecs to a few kiloparsecs. Young radio AGN may hold vital clues about many open questions regarding radio jet triggering, duty cycles, and the role of radio jets in imparting AGN feedback to their host galaxies. Therefore, the investigation of these newborn radio AGN can give us a direct view of many transient processes and better inform simulations of galaxy formation and evolution.

The broad frequency coverage (1.2-116 GHz) and improved sensitivity (10X better than the Jansky Very Large Array) of the next generation Very Large Array (ngVLA) will provide a unique parameter space to conduct statistical studies of young radio AGN across a broad range of AGN luminosities and redshifts (Nyland et al. 2018, Patil et al. 2018). The Main Array will provide the sub-arcsecond resolution needed to resolve the sub-kiloparsec structures of sources found at z ~ 1-6, while the Long Baseline Array will provide the finer resolution needed to resolve the parsec scale radio emission at z ~ 2 in the highest frequency band. In combination with low-frequency (< 1 GHz) observations from prospective instruments such as the Square Kilometre Array and next generation Low Band Observatory, the ngVLA will enable the robust characterization of the spectral energy distributions of young radio AGN, which will place constraints on their ages and evolutionary stages. Ultimately, the ngVLA will enable us to obtain the structural, spectral, and polarimetric information on radio jets necessary to quantify their energetic impact on their hosts and improve our understanding of their role in galaxy evolution.

This article continues a regular feature intended to highlight contributions to the ngVLA Science Book. We are especially interested in showcasing work done by early-career researchers. Anyone wishing to volunteer to author a feature should contact Joan Wrobel.

New Assistant Director for Science Support & Research

Tony Beasley (NRAO Director)

Prof. Patricia Henning

I am pleased to announce that Prof. Patricia (Trish) Henning will be the next NRAO Assistant Director for Science Support and Research (AD/SSR), initially based primarily in Charlottesville, but with significant presence in New Mexico. 

Dr. Henning began her research career as a postdoctoral research associate in the Netherlands at Dwingeloo/Netherlands Foundation for Research in Astronomy, after gaining her Ph.D. in Astronomy at the University of Maryland. Later, she moved to the University of New Mexico (UNM) as an Assistant Professor (eventually full Professor), held the position of Director of the UNM Institute for Astrophysics for more than fifteen years, and most recently was the UNM Associate Vice President for Research. In these roles, Dr. Henning has successfully continued her research career while taking on significant administrative responsibilities, and has been highly active in public outreach and mentoring. She has held several senior committee roles throughout her career, including Head of User Programs for the Long Wavelength Array, Chair of the U.S. Square Kilometre Array Consortium, and NRAO User Committee member. In recent years, she has personally contributed to several Diversity and Inclusion initiatives, and this area is a strong interest. 

Her time working in Europe, the U.S., China, South Africa, and Australia will bring a wealth of experience in administration, understanding of radio astronomy research, experience with facilities, project management, and recruitment and mentoring of scientists and students. Her collaborative approach, with a focus on respect, communication, and relationships, will greatly assist her in supporting the scientific environment and scientific staff here at the Observatory. 

I would like to thank Dale Frail for his excellent efforts as interim AD/SSR over the past several months, including handling several key initiatives. Dale will be returning to his outstanding research program focused around time-domain astronomy.

Dr. Henning will arrive in Charlottesville and take up the position as AD/SSR in late August. Please join me in welcoming her to NRAO! 

2020 Jansky Fellowships Awarded

Dale Frail (Interim AD, Science Support & Research)

The National Radio Astronomy Observatory (NRAO) Jansky Fellowship program provides outstanding opportunities for research in astronomy. Jansky Fellows formulate and carry out investigations either independently or in collaboration with others within the wide framework of interests of the Observatory. The program is open each fall to candidates with interest in radio astronomy techniques, instrumentation, computation, and theory. Multi-wavelength projects leading to a synergy with NRAO instruments are encouraged. We are pleased to announce that five new Jansky Fellows will be joining NRAO in fall 2020.

Kimberly Emig is completing her Ph.D. at the Leiden Observatory with Alexander Tielens and Huub Rottgering. She explores the dynamical evolution of the interstellar medium (ISM) and its coupling with star formation largely through an expertise in radio recombination lines. Kimberly has demonstrated that radio recombination lines are viable pathways to probe the physical properties of the ISM out to cosmological distances. As a Jansky Fellow, she will use radio recombination line observations in large populations of galaxies and in the local ISM to investigate the characteristics of photo-ionized gas, its relationship to massive stars, and its role in the evolution of galaxies.

Bang Nhan received his Ph.D. from the University of Colorado at Boulder under the supervision of Prof. Jack Burns and Dr. Richard Bradley as a Reber Fellow. His thesis work involved developing the Cosmic Twilight Polarimeter (CTP), a testbed system to constrain the foreground synchrotron spectrum for the spatially-averaged (global) cosmological 21-cm measurement using dynamical polarimetry. As a Jansky Fellow, Bang will lead the development effort of the next generation CTP, which consists of upgraded frontend and antenna design for better instrumental calibration and stability.

Pallavi Patil is a Ph.D. candidate and Reber Fellow at the University of Virginia. Her dissertation research focuses on understanding the nature of a rare sample of heavily obscured radio quasars with compact and newly-triggered jets, found at the epoch of cosmic noon. As a Jansky Fellow, she will continue to use NRAO radio facilities to investigate the role and impact of radio jets on their surrounding medium during early phases in the life cycles of luminous radio AGN.

Dyas Utomo received his Ph.D. from the University of California, Berkeley and went on to Ohio State University as a postdoc. His goal as a Jansky Fellow will be to understand the physical process that governs the conversion from atomic to molecular gas and from molecular clouds to star formation. To achieve that objective, he will use multi-wavelength observations to measure the properties of gas, dust, and star formation at high physical resolution (~ 100 pc) in a large sample of nearby galaxies. Dyas is a member of the PHANGS, EDGE, and z0MGS collaborations, where he lead the PHANGS-VLA project to observe the atomic gas (HI) in galaxies that have CO measurements from the PHANGS-ALMA.

Jacob White received his Ph.D. from the University of British Columbia and was previously a Research Fellow at the Konkoly Observatory (Budapest, Hungary). Jacob has extensive experience observing with ALMA and VLA to constrain the abundance, distribution, and morphological features of the gas and dust in the circumstellar disks. Jacob is also leading an effort to build more comprehensive submillimeter to centimeter wavelength spectra of stars. Accurate stellar spectra at long wavelengths are required to study unresolved debris systems with ALMA and VLA and to constrain the impacts of space weather on habitability of planets orbiting ultracool dwarf stars.  As a Jansky Fellow, Jacob will continue to use NRAO facilities to study circumstellar debris and the radio emission of stars.

Recent Media Releases

The Strange Orbits of 'Tatooine' Planetary Disks 19 March 2020

From the Archives

Ellen Bouton

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About this month's photo: Honoring the "March Madness" that did not happen in 2020. Over the years, NRAO staff members have participated in a variety of sports, organized in differing degrees from occasional informal games to regular league play: softball, volleyball, golf, bowling, basketball, and even cricket in Socorro in 1980-1981. This photo of basketball in Charlottesville was taken in the late 1970s.  Left to right: Bill Wireman, Bob Fromm, Gail Browning, Barry Turner, Stan Hansen, and Betty Stobie.

From the Archives is an ongoing series illustrating NRAO and U.S. radio astronomy history via images selected from our collections of individuals' and institutional papers. If readers have images they believe would be of interest to the Archives, please contact Ellen Bouton.