HERA Commissioning Trip

I spent the first week of September at the HERA site in South Africa in preparation for our first season of science observing. My primary mission was to familiarize myself with the actual hardware of the telescope, establish a “ground truth” for the configuration, and create tools so we can quickly diagnose problems and get them fixed. This involved meeting the folks at the SKA-South Africa office in Cape Town and the locals from the town of Carnarvon who are actually building the HERA dishes. I also had the chance to explore the array, and change out a front end module. Below are a couple panoramic images I took on the trip.

View from a HERA feed

View from feed – Spherical Image – RICOH THETA

Building a dish

Dish building – Spherical Image – RICOH THETA

As far as diagnostic tools go, HERA now sends me an email every morning with some nice plots showing the health of the array and a summary of antennas that might be misbehaving. We started the trip with at least four problem-antennas, and now we’re down to a half (one out of two polarizations). Of course troubleshooting is a bit slower now that I’m back in the states, but we also established some communication channels with the builders out there, so we can get about daily updates and fixes.

Science observing, here we come!


We got some great news this week — the National Science Foundation has awarded us an Advanced Technologies and Instrumentation (ATI) grant to deploy the EPIC correlator on the Long Wavelength Array station in Sevilleta, New Mexico. This is a great opportunity to further develop the technology which will open the doors to very large, compact radio telescopes, as well as wide-field, high time resolution surveys.

LWA-SV, photo credit Greg Taylor

HERA gets an extension

Thanks to the monumental efforts of Jackie Hewitt at MIT, the HERA telescope will be receiving a significant boost from the Gordon and Betty Moore Foundation. The added funding will allow us to develop front-end feeds to be sensitive to a wider range of radio frequencies (and thus a larger portion of the history of the Universe), and to build 110 additional dishes (for a total of 350). Many of the additional dishes will be “outriggers” which will significantly improve HERA’s imaging ability — a key aspect for combining HERA’s measurements with other probes like the James Webb Space Telescope.

A full story on the funding can be found here: MIT’s Jacqueline Hewitt and HERA team given $5.8M boost to detect cosmic dawn.

HERA dishes
Some of the first HERA dishes. Photo credit Josh Dillon.

NSF Fellowship

This week I received an offer for the NSF Astronomy and Astrophysics Postdoctoral Fellowship! The research under this fellowship will be to  to develop an imaging-based power spectrum pipeline for the HERA experiment, building on my previous work as well as new observations from the MWA phase two — an imaging/redundant hybrid array configuration that I designed. I will also push forward on the framework to extract useful science from cross studies between 21cm EoR observations and other probes such as galaxy surveys with the JWST.

The NSF AAPF is unique because it also includes an educational component, which I’m particularly excited about. I will engage a group of undergraduates at ASU to upgrade the Very Small Radio Telescope program. I plan to incorporate technologies which are becoming more and more affordable, such as the Raspberry Pi and Software Defined Radios, to lower the investment cost of the VSRT and make it accessible to more college and high school classrooms.

This is a very exciting opportunity, and I can’t wait to get started!

Meeting, Busy Days, and a Conference

I’ve spent the last week on the Caltech campus for an MWA project meeting, EoR “busy days”, and the third annual Science at Low Frequencies conference. It has been a really great mix of getting caught up on lots of science going on, exploring new collaborations, and rolling up our sleeves to get work done. Here are a few highlights:

  • We officially released Version 1.0 of pyuvdata and submitted it to the Journal of Open Source Software (JOSS). This code will transform the way our growing collaborations analyze and compare data, and use simulations to interpret results.
  • I gave an update on my group’s progress towards enabling direct imaging radio arrays with our software implementation of the MOFF correlator.
  • I had a lot of great conversations with current and future collaborators. In particular, I discussed expanding my direct imaging work to projects looking for extra terrestrial intelligence with the MWA as well as observing lightning at low frequencies (5-10 MHz) with the LWA. I’m looking forward to getting my hands on both types of data and digging in.

In general it’s really exciting to see the science output explode in low frequency radio astronomy. Advances in digital signal processing and high performance computing have enabled a lot of new instruments, and the last few years have seen a huge shift from demonstrating these telescopes to reaping the scientific output.

Earth and Space Open House

Last week was the first Earth and Space Open House of the year at SESE. I missed a few of them last year, so I was happy I could participate this time around – especially because I could report that HERA has officially received funding. The LoCo group had a lot of fun talking about radio frequencies and the radio sky with folks from all over the Valley of the Sun. I’m always surprised at how few kids know what a “rabbit-ear antenna” is. It makes it hard to use my go-to explanation for how simple radio telescopes can be.img_0330

The next Open House is coming up in just a couple weeks on October 14!

Office Shenanigans

Contrary to most places in the Unites States, Arizona summer means most of your time is spent indoors under the protection of glorious air conditioning. The prolonged confinement can sometimes drive one a bit stir crazy – especially around the office. As we finish up papers and dig deep into HERA commissioning, the office at ISTB4-690 has taken on a couple “side projects.”


Our new office door name plate. “Cosmologies observed, while U wait” — we didn’t say how long you have to wait.

Inspired by Sean Carroll’s blog post following the announcement of LIGO’s gravitational wave detection, officemate Danny Jacobs and I decided to make our own set of wagers on the progress of science over the next ~decade. For each milestone, we pick an over/under date, and the name means that person chose “under” – in other words that person thinks the milestone will be achieved before the date.

Because the text is tiny, here are the wagers for future reference:

  1. Directly detect dark matter, 5 November 2021, Danny
  2. Discover particle not in the Standard Model (5-sigma), 1 December 2018, Adam
  3. Convincing evidence of non-Earth life, 5 October 2021, Danny
  4. Detect EoR via 21cm (accepted to journal), 5 May 2020, Adam
  5. $1000/kg launch to low earth orbit, January 2020, Danny
  6. Person on Mars, 1 April 2025, Adam

A few clarification for the record – Judd is the final judge, so if he’s convinced of non-earth life, it counts. The EoR must be detected through 21cm, but not necessarily power spectrum (although we’ll do everything we can to make sure it’s HERA).

You’ll notice the wagers were placed August 3, one day before the CMS collaboration announced that a bump at 750 GeV has gone away. I’m not ready to admit defeat on that one yet, but that bump is what I was hoping would pan out. Oh well…

MWA Phase 2 – Hexes!

The installation of 128 new MWA tiles is well underway, and the Cosmos Consultant (Gregory Rowbotham of ICRAR) has been documenting the progress on his blog. Check it out:

MWA Phase 2
Week 2 – Day 3 – Dipoles, Dipoles, Dipoles, The Cosmos Consultant

The picture above shows a piece of the new MWA “hexes” – two new array cores featuring antennas arranged in hexagons. I’m particularly excited about these cores because they will enable new analysis techniques like delay spectra and redundant calibration. Plus, I designed the layout 🙂

HERA Data Busy Week

Last week marked a major milestone for HERA data processing. After three and a half intense days of coding in Cape Cod, we internally released the data from the first commissioning run. I worked primarily on a new python module, pyuvdata, for handling interferometric data. This is meant to be a general purpose tool for radio interferometry, but will be especially crucial for the HERA collaboration to get as many people as possible looking at the data with all kinds of analysis workflows. I wrote a lot of unit tests and checks to ensure the code is working properly. At the end of the week the tests cover 94% of the code. I’d say that’s pretty good, especially when I had two other scientists sitting next to me aggressively adding code the whole time.

Screen Shot 2016-06-03 at 11.01.07 AM

We also had a little time to enjoy the beach 🙂