Abstracts for 2023 Western Conference

Abstracts for 2023 Western Conference

OVRO, Bishop, CA, March 17-18, 2023


Keynote speech: Dr. Vikram Ravi, Caltech
Title: Renewing our view of the radio sky

Radio astronomy is changing. Where large, multi-user facilities operated by national observatories were once pre-eminent, the field is entering an era of experiments with diversified, dedicated instrumentation. This is powered by the drastic reduction in cost and democratization of access to cutting-edge receiver and digital signal processing hardware. The Owens Valley Radio Observatory (OVRO) is a microcosm, and pioneer, of this transformation, with several large projects underway that address some of the most exciting questions in astronomy: the habitability of exoplanets, matter at the very edges of black holes, the sources of the enigmatic fast radio bursts (FRBs), and the origins of the foam of galaxies we call the cosmic web. I will focus on the Deep Synoptic Array (DSA) program. The DSA-10 and DSA-110 arrays were targeted at pinpointing FRBs to specific galaxies, thus illuminating their origins, and enabling their use as probes of the large-scale structure of the Universe. In the near future, the DSA-2000 array will be the most powerful radio telescope yet built, exceeding the survey speed of the Square Kilometre Array by a factor of six while matching its sensitivity. Consisting of 2000 5-m dishes operating between 0.7-2 GHz and distributed over a 19x15km site in Nevada, the DSA-2000 will inform our cosmic history from the earliest galaxies to our Milky Way, reveal the rarest types of neutron stars, and unravel the astrophysics of gravitational-wave sources. We are little over a year from construction starting on the DSA-2000, and this talk will be presented from the epicenter of this project!

Title: Observations of Ultra-Low Frequency Waves at Anchorage, Alaska
Whitham D. Reeve

The solar wind is the agent for many interesting geomagnetic phenomena recorded by ground magnetometers. Among these are Ultralow Frequency Waves (ULF Waves), the modern name given to periodic variations in Earth’s magnetic field observed on the ground. The phenomenon has been known throughout the years by several other names including micropulsations and magnetic pulsations. ULF waves have frequencies of a few mHz to a few Hz, corresponding to periods from several minutes to fractions of a second.

ULF Waves have wavelengths comparable to the scale size of the magnetosphere and play a fundamental role in transporting energy throughout the geospace system. Scientific investigations of ULF Waves reveal information about the magnetosphere’s particle density and structure, particularly in the parts of the magnetosphere that are hard to directly measure. An ultimate goal of these studies is a better understanding of space weather and its effects on Earth and technology. In spite of considerable work over many years, the causes of ULF Waves are not yet fully understood. Indeed, the scientific literature contains conflicts in many details.

This paper contains two parts: Part I provides 1) a tutorial on ULF Waves, 2) ULF Wave classifications, 3) a brief description of the Anchorage Radio Observatory, and 4) a description of the SAM-III magnetometer used to collect the data; Part II provides descriptions of ULF Wave observations at Anchorage, Alaska from 2010 to 2022 and a discussion of those observations.

Title: The 2021/2022 Observation Campaign of FRB20201124A
Author: Wolfgang Herrmann, Astropeiler Stockert e.V.

Fast Radio Bursts (FRBs) are bright pulses which are believed to come from cosmological distances due to their large dispersion. Some of these pulses repeat, and such a repeater is known as FRB20201124A. This source has been observed by the 25-m dish of the Astropeiler observatory during the period from April, 2021 to March, 2022, accumulating ~ 1400 hours of on-source time. This observation activity was complemented by observations with the Westerbork (Netherlands), Onsala (Sweden) and Torun (Poland) telescopes. A total of 46 bursts were detected.

The talk will give an overview of the observation campaign and the science results derived from the observations.


Conference Presentations from Athens State University on the STEMSTAT project

Title:  1) STEMSAT-1 Launching December 2023!
Author: Dr. J. Wayne McCain, Athens State University

STEMSAT-1 (formerly known as SARA-SAT1) is manifested for launch late fourth quarter 2023 on a Vaya
Space hybrid rocket from Cape Canaveral Space Force Station along with another commercial satellite. First announced at the 2017 Western Conference, the primary objective of this 3U cubesat is to involve students from kindergarten through college level in various aspects of designing, building, launch, and mission control of the satellite as a STEM learning activity. The secondary scientific mission is to monitor VLF (50-200 KHz range) radio signals that won't otherwise penetrate the Earth's atmosphere and translate that data to a UHF, 430 MHz that is transmitted to ground stations world-wide. This paper will update the progress on STEMSAT, including the project's collaboration with SARA.


Title: 2) Building A Simple, Low-Cost Ground Tracking Station For Receiving the STEMSAT
Authors: David O. Ausley, Athens State University Alumnus, Amelia Claire McCain, Student, Athens Middle School

Once the STEMSAT small satellite is launched into orbit, ground stations worldwide (ranging from Hawaii, South Africa, to Wales) will be able to capture the translated VLF radio signal data on the 70 cm Ham Radio band. This paper summarizes simple and homebuilt antennas and inexpensive handheld radios that can serve to receive the satellite data.

Title: 3) VLF Radio Signals From Space - What Can STEMSAT Expect?
Authors: Dr. Mel Blake, Resident Astronomer, University of North Alabama (UNA), Harmonie R. Wildharber, Student, UNA

What are some of the radio signals that the STEMSAT satellite may encounter in its low to medium altitude Earth orbit and what is the significance of their translation to UHF frequency and transmission/reception on Earth? This paper is based on research into these topics by UNA student Harmonie Wildharber (an Alabama Academy of Science research winner) and her faculty advisor and Resident Astronomer Dr. Mel Blake.

Title: 4) The Future Is Now - An Overview of the BS in Aerospace Systems at Athens State University
Authors: Dr. Mary Jo Marggraff, Adjunct Professor Athens State University, Dr. J. Wayne McCain, Professor

There is a new 'space race' underway driven largely by the involvement of commercial players such as Elon Musk's SPACE-X and others in the marketplace. To the Moon - then Mars! But, shortages in professional labor sources abound in the aviation and space-based industries. This paper introduces a new degree program at Athens State University to facilitate training in the very skill sets that are required to ease these labor shortfalls.

The program includes Aviation Management and Space Systems concentrations. Athens State has teamed with Wallace State Community College for actual pilot training.


Title: Exploring Pulsar Timing Residuals
Dan Layne, Deep Space Exploration Society

Pulsars are highly magnetized, rapidly rotating neutron stars. Pulsar timing is the regular monitoring of the rotation of a neutron star by tracking the arrival times of the radio pulses at the telescope. Averaging over many pulses yields an average pulse profile. Although the shapes of individual pulses can vary considerably, the shape of the average profile at a given observing frequency is quite stable. For timing, the average pulse profile is correlated with a high signal-to-noise template to determine the pulse time of arrival (TOA). Timing residuals are the differences between the observed TOAs and the predicted TOAs based on the current timing model parameters. Strong millisecond pulsars (MSPs) with narrow pulse profiles provide the most accurate arrival times. An array of such MSPs spread over the sky is called a pulsar timing array (PTA). The goal of a PTA is to detect correlated structures in the timing residuals of dozens of MSPs, potentially including distortions of interstellar space from nanohertz (i.e., periods of years) gravitational waves passing through our galaxy. The purpose of this paper is to explore timing residuals and noise modeling of individual MSPs from the NANOGrav PTA project. Specifically, narrowband parametric models and TOA timing data from the NANOGrav 12.5 year data set are used to analyze a few brighter MSPs, including PSRs J1713+0747, B1937+21 and J2145-0750. Pulsar detection is illustrated with PRESTO plots from the Green Bank Observatory 20-meter telescope, while the actual NANOGrav timing data was collected with Arecibo and the Green Bank 100-meter Telescope from 2004 to 2017. The narrowband models are based on a generalized least squares fit of parameters that includes uncorrelated white noise as well as red noise. Software tools include TEMPO2 and PINT (high precision pulsar timing), as well as ENTERPRISE, which provides Bayesian inference methods for reasoning with uncertain timing and noise models.

Title: Principles of and a Proposed Phased Array Radio Telescope
Author: Curt Kinghorn

An explanation will be made of the principles and components of phased arrays as applied to a radio astronomy telescope including a comparison of a phased array telescope to an interferometer and a single antenna system. In addition, the presentation will also include a brief description of antennas,

their applications to radio astronomy systems generally and in particular to phased array telescopes. Using these phased array principals, a proposed am ateur aperture synthesis phased array telescope system will be presented.  The telescope, though amateur, would be a scientifically powerful and useful

scope. The scientific purpose of the telescope will be to measure time-varying radio phenomena on time scales of microseconds to an hour and also on time scales of several months. The proposed telescope will be able to record data at four frequencies, 50 MHz, 100 MHz, 200 MHz and 400 MHz to provide a spectral sky survey as well. The System should be able to identify and map FRBs, pulsars, transients and the evolution of phenomena such as expanding supernova remnants. The proposed scope should also complement the astrometric and photometric work being done to great effect in visual astronomy. Similar to the SuperSID distributed by SARA, the proposed system would be deployed continent-wide by amateurs in any number of locations. The telescope would be an improvement on and add to the scientific knowledge shown in a 2003 paper titled A Survey for Transient Astronomical Radio Emission at 611 MHz, Katz, C.A., Hewitt, J. N. et al, https://arxiv.org/abs/astro-ph/0304260