NRAO Newsletter
Volume Vol#, Issue Iss#
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NRAO Newsletter
Volume Vol#, Issue Iss# • Day# Month# Year#
The Atacama Large Millimeter/submillimeter Array (ALMA) on the Chajnantor Plateau in Chile. Photo by Jeff Hellerman (NRAO/AUI/NSF).
Upcoming Events
IAU General Assembly XXXII
August 6-15, 2024 | Cape Town, South Africa
NRDZ Partnership and Workshop Series
Sept 9 - 11, 2024 | Green Bank, West Virginia
Follow the Monarchs: A Journey to Explore the Cosmos at (Sub)milliarcsecond Scales with the ngVLA
Nov 11 - 14, 2024 | Morelia, Mexico
ngVLA Project News
Technology Development at Canada's Herzberg Astronomy & Astrophysics
Image Credit: Sara Salem Hesari/HAA/NRC
Engineers at HAA are working on the preliminary designs for the ngVLA Band 5 receiver system. Band 5 is one of the high-frequency receiver systems planned for the ngVLA, spanning the 30-50 GHz range. This development leverages HAA's previous experience building ALMA's workhorse Band 3 receivers, spanning 84-116 GHz. Canadian Band 5 development and manufacture could become an important component of the ngVLA project going forward.
Follow the Monarchs: A Journey to Explore the Cosmos at (Sub)milliarcsecond Scales with the ngVLA
This ngVLA international science conference will be held November 11-14 in person in the UNESCO World Heritage site of Morelia, Mexico. The conference will highlight and explore the novel scientific opportunities that will unfold with the unprecedented angular resolution and sensitivity capabilities offered by this new flagship facility. The conference will coincide with the Monarch butterflies completing their migration journey from Canada and the US to the mountains surrounding Morelia. Abstract submission for oral presentations closes Monday, July 29, and early registration is available until September 1. To take these actions, see the conference website.
ngVLA Science - Prospects of Detecting a Jet in Sgr A*
Above: Detecting Sgr A*'s simulated jet requires next-generation VLBI arrays (red outline). 115 GHz is optimal for jet detection but offered only by the ngVLA. Adapted from Chavez et al. (2024).
At the center of the Galaxy lies a 4 million solar-mass black hole, Sgr A*. The Event Horizon Telescope (EHT) has resolved the structure of Sgr A*’s accretion flow and magnetic field structure on event horizon scales (EHTC 2022a, 2024b).
Numerical simulations of the accretion flow best supported by the observations predict a relativistic jet (EHTC 2022e), yet one has never been detected. If this prediction is true, how could it be that a jet in the Galactic Center could remain undiscovered in the five decades of study of Sgr A* since its discovery (Balick & Brown 1974), and could this jet be detected with VLBI?
If Sgr A* has a jet, it is likely hidden in plain sight: ionized plasma in the line of sight to the Galactic Center scatters light at radio wavelengths, which blurs and distorts the image. The effects of scattering decrease with increasing frequency: 86 GHz is the lowest frequency at which Sgr A*'s source structure overcomes scattering effects (Issaoun et al. 2019). However at these frequencies, the jet is faint and difficult to detect. For example, at 86 GHz the simulated jet contributes only about ~15% of the total flux density (Chavez et al. 2024).
Our imaging tests of the simulated jet with existing VLBI arrays confirm that they are unable to detect the faint jet: next-generation VLBI is needed (see figure, Chavez et al. 2024). Various next-generation arrays, including the ngEHT and the ngVLA, are capable of jet detection at 86 GHz. But the ngVLA uniquely offers observing capabilities at 115 GHz, which is a "sweet spot" for jet detection. At 115 GHz the jet has a comparable brightness to 86 GHz, but the effects of interstellar scattering are significantly reduced. Also, the high sensitivity and dense (u-v) coverage at ~100 microarcsecond scales makes the ngVLA ideal for capturing the diffuse, extended emission from the jet. Next-generation VLBI arrays such as the ngVLA will be essential to determining the true nature of Sgr A* and the Galactic Center environment.
Since 2015 the acronym ngVLA has appeared in 1170+ publications indexed in the SAO/NASA Astrophysics Data System. This article continues a regular feature intended to showcase some of those publications. We are especially interested in showcasing work done by early-career researchers. The collection of showcase articles can be viewed online. Anyone wishing to volunteer to author a feature should contact Joan Wrobel.
ALMA Program News
Image Credit - Pablo Carrillo (ALMA)
ALMA Observing Status
ALMA continues normal Cycle 10 observations. The 12-m Array is currently completing repositioning from configuration C-6 to configuration C-5, which provides a 0.54" beam at 1.3mm on 1400m baselines, before moving to more compact configurations to finish out Cycle 10. Although atmospheric water vapor varies, it is best during current altiplanic winter months; daytime highs are generally below freezing during altiplanic winter under prevailing dry westerly winds.
Cycle 11 Status
Cycle 11 Principal Investigators were informed of the status of their Cycle 11 Observing Proposals during the fourth week of July. ALMA proposals are selected by competitive peer review through either the distributed peer review process or the ALMA Proposal Review Committee (APRC). Cycle 11 is currently scheduled for observations from October 2024 to September 2025.
NAASC Call for Conference and Workshop Support is Open
The NAASC invites members of the North American scientific community to apply for funding in support of conferences and workshops which encourage the participation of students, postdocs, and early career researchers. Events must be scheduled between Oct 1, 2024 and September 30, 2025 to be eligible. For awarded events, the NAASC can provide monetary funding (up to $15,000 per event). As needed, the NAASC can also provide logistical support (e.g., webinar platform, event website), access to facilities (NRAO rooms and auditorium in Charlottesville) and content.
Proposals requesting more than $5,000 should apply before Wednesday, August 28, 2024 for full consideration. For other proposals with lower monetary requests, we will accept applications at any time while funds for fiscal year 2025 last. For instructions on how to apply, eligibility criteria and other details on this program, please look at the program webpage.
ALMA Primer Video Series
The ALMA Primer Instructional Video series, which can be found on the Science Portal, is designed to provide a basic introduction to radio interferometry, calibration, imaging, and other topics in short (5-10 minute), easy-to-digest segments. As a work in progress, new videos are released periodically. A new video, an Introduction to Sidebands, Basebands and Spectral Windows, was released in early July, and several more will be released later this summer.
Other videos in the series include an Introduction to Radio Interferometry, Calibration, CLEAN, and much more. Subscribe to the ALMA Primer Video Series YouTube channel to be alerted to new videos as they are released.
We are always looking for ideas for new videos, and especially looking for people who would like to help with script generation, animation, and narration. If you have an idea or would like to join the Primer Video Working Group (at any level of effort), please contact Gerald Schieven.
NAASC Activities
The Cool Stars conference, Cool Stars 22, was held in a hybrid format (both in-person and online) in San Diego from the 24th to the 28th of June, with some support from the ALMA North American Science Center. The conference Program may be found at the conference website. It was announced that Cool Stars 23 will be held in Tokyo, Japan!
Upcoming Meetings
- September 24-27, 2024: Born in Fire: Eruptive Stars and Planet Formation, Santiago, Chile - NAASC sponsored
Astronomical Data Analysis Software and Systems 2024 - Registration now Open
Registration is now open for the 34th annual conference on Astronomical Data Analysis Software and Systems. The conference will be held November 10-14, 2024 at the University of Malta Valletta Campus, hosted by the Institute of Space Sciences and Astronomy. The meeting is an in-person event with a virtual component.
ADASS provides a forum for scientists and programmers concerned with algorithms, software and software systems employed in the acquisition, reduction, analysis, and dissemination of astronomical data. An important element of the programme is to foster communication between developers and users with a range of expertise in the production and use of software and systems. The programme consists of invited talks, contributed oral and display papers, tutorials, user group meetings and special interest group meetings (collectively "Birds of a Feather" meetings).
Key dates:
- Registration Opens: 14 June 2024
- Financial Aid Registration Deadline: 28 July 2024
- Early Bird Registration Deadline: 20 September 2024
- Final Registration Deadline: 04 November 2024
SMA Call for Standard Observing Proposals - 2024B Semester
The Call for Standard Observing Proposals for observations with the Submillimeter Array (SMA) is for the 2024B semester with observing period nominally 16 Nov 2024 - 15 May 2025 (subject to adjustment as needed).
The deadline for proposals for the 2024B semester will be:
12 Sep 2024 9PM Cambridge (EDT) = 13 Sep 2024 1AM GMT = 13 Sep 2024 9AM Taipei
Please note the change in the deadline time of day relative to previous calls.
The SMA proposal system will open for users to begin crafting their submissions on or before August 15 at the SMA Observer Center (SMAOC) and will include full details on time available, and the proposal submission process.
Details on the SMA capabilities and status can be found at the SMA status website; proposal creation and submission is also done through the SMAOC. We are happy to answer any questions and provide assistance in proposal submission; simply email with any inquiries.
Recent Science Media Releases
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Telescope Tag-Team Discovers Galactic Cluster's Bizarre Secrets
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Old Data, New Tricks Discover Pulsar in Galactic Plane |
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AUI and the NSF NRAO Announce the Recipients of the 2024 AUI Board of Trustees NAC Bridge Scholarship Award |
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Contact the NRAO press office to share your new and exciting science results. |
From the Archives
Ellen Bouton
About this month's photo: On 6 August 1956, the West Virginia Radio Astronomy Zoning Act became the first legislation in the world intended specifically to protect basic research, and on 19 November 1958 The National Radio Quiet Zone (NRQZ) was established by the Federal Communications Commission to minimize potential harmful interference to the NRAO in Green Bank, WV, as well as to the radio receiving facilities for the US Navy in Sugar Grove, WV. This 1979 photo shows NRAO's frequency van, used to detect sources of interference in and around Green Bank, long before the era of ubiquitous computers, cell phones, drones, and satellites, when threats were more likely to come from malfunctioning household appliances or poorly sited TV broadcast towers. NRAO has a 60-year history of involvement in national and international spectrum management, advocating for the protection of the radio astronomy service, and is currently working with various stakeholders towards a mutually beneficial National Spectrum Strategy (NSS); see NRAO comments on the NSS, endorsed by the AAS. NRAO's Spectrum Management site describes current spectrum activities.
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.
