The 38th Annual New Mexico Symposium
  17 February 2023 - National Radio Astronomy Observatory


To view abstracts and posters (in pdf), click on the posters' titles.

No. Title Presenter

Abstract: Classical photometric and spectroscopic observations of Jupiter and Saturn do not constrain their interior structure, composition, core mass, sub-surface rotation, etc. Such inferences would help resolve competing theories of giant-planet formation, which predict specific interior signatures. Furthermore, giant-planet atmospheres show a rich variety of dynamical phenomena that could help us understand how energy is transferred and is coupled to interior processes. Seismological observations are an exciting potential tool for accessing the deep interiors of giant planets, as well as directly quantifying wind-driven atmospheric dynamics. JIVE is a project that utilizes Sunspot Solar Observatory in New Mexico to provide nearly-continuous Doppler-imaging data for our solar system's giant planets and allow for new ways to study their interior and atmospheric properties. It is very complementary to the science goals of the NASA`s JUNO mission, and could provide instrumentation guidelines for future gas- or ice-giant missions.

Cristo Sanchez (NMSU)

Abstract: Asymptotic Giant Branch (AGB) stars have long been of interest to astronomers. These stars are in a crucial stage of stellar evolution, losing their mass and transitioning into planetary nebulae. Characterizing the long-term evolution of mass loss through a mass-loss formula in these stars has been elusive. To find a mass-loss formula, we analyzed a set of AGB stars in the Large Magellanic Cloud. From models, we expect that a reasonable mass-loss formula should create a sharp turn in luminosity-mass space. We developed a method to determine a mass-loss formula by analyzing the distribution of stars in the pulsation period-luminosity plane, working around the problems present with typical fitting methods. The dimensions of the strip are used to determine a power law formula while minimizing the difference between predicted and observed mass-loss rates. Through this, we found four mass-loss formulas for four different subsets of the AGB population. These formulas reproduce the sharp turn we expect from observations of AGB populations and from theoretical models, putting formulas from theory and observation into agreement. As a next step, we are generating grids of atmospheric models of AGB stars to compare against the stars seen in the Large Magellanic Cloud. We will be examining how models with typical parameters compare, how they compare when these parameters are pushed to their plausible physical limits, and investigating what details and physical processes might need to be accounted for to make these grids fit stars observed in the LMC.

Henry Prager (NMT)

Abstract: The Solar Orbiter (SolO) Polarimetric and Helioseismic Imager (PHI) is now providing the first ever photospheric magnetogram observations taken from off of the Sun-Earth line. These alternate perspectives are particularly valuable for the creation of global solar magnetic maps that are commonly used as the inner boundary condition for coronal, solar wind, and heliospheric models. We present the preliminary integration of SolO/PHI Full Disc Telescope (FDT) observations into the Air Force Data Assimilative Photospheric flux Transport (ADAPT) model. Particular attention is paid to the assimilation of overlapping magnetograms during periods when SolO is near the Sun-Earth line. We also investigate periods when SolO observes flux emergence on the `farside` of the Sun and compare observed flux evolution with the modeled flux transport in ADAPT. Finally, we comment on the future prospects for regular inclusion of these science data in real-time ADAPT products, particularly in light of SolO`s eventual high-latitude orbit. This work utilizes data produced collaboratively between the Air Force Research Laboratory (AFRL) and the National Solar Observatory. The ADAPT model development is supported by AFRL.

Sam Schonfeld (Boston College)

Abstract: Prestellar cores are nitrogen-rich, gravitationally bound dense regions within molecular clouds which will eventually lead to star formation. Throughout the ISM, the two stable isotopes of nitrogen, 14N and 15N, are generally found in a ratio of around 330 (Hily-Blant et al 2020). The nitrogen isotopic fractionation ratio has been observed in fewer than 10 prestellar sources, but no chemodynamical core models have successfully predicted the observed ratio of 14N to 15N, which differs from the global value, or constrained the fractionation of nitrogen-bearing isotopologues. We observed the 14N and 15N isotopes of o-NH2D in prestellar core L43-E using the Kitt Peak ARO 12m radio telescope, and provide constraints on the fractionation ratio as a function of 15NH2D excitation temperature.

Reynier Squillace (University of Arizona)

Abstract: tarless and gravitationally-bound prestellar cores are the incipient phase of star and planet formation. We must understand the evolution of the physical and chemical structure of prestellar cores since the initial conditions of the future planet-forming disk are set during this phase. Deuteration, where deuterium replaces one or more hydrogen atoms in a molecule, is a chemical probe of cold, dense gas that may be used to constrain the evolution rate of starless and prestellar cores. Deuterium fractionation proceeds via either gas-phase reactions (i.e. NH2D, N2D+) or on the icy surfaces of grains (CH2DOH, HDCO). It was long thought that deuteration on grain surfaces would be difficult to observe until a forming protostar`s heat sublimated the ices, but recent observations of starless and prestellar cores indicate that (still not well understood) desorption processes liberate some molecules from the surface ices into the gas phase where they can be observed via rotational spectroscopy. The Barnard 10 (B10) region of Taurus is a pristine environment, undisturbed by feedback from protostar formation, to study the evolution of a dozen starless and prestellar cores. We surveyed the core peak positions of B10 in HDCO with the Arizona Radio Observatory 12m telescope and discovered that this molecule is prevalent (100% detection rate) and bright (lines up to 0.8 K, much brighter than CH2DOH lines towards the same sources). In this study, we compare the column density of HDCO and abundance ratio of HDCO/H2CO to the observed and modeled properties of the cores.

Hanga Andras-Letanovszky (University of Arizona)

Abstract: Before stars form, their material exists as dense clouds of gas and dust called pre-stellar cores that occur in interstellar molecular clouds. When observing pre-stellar cores with single telescopes, it is difficult to observe low frequency radio lines due to the poor spatial resolution which is often several arc-minutes and larger than the physical size of the cores. To circumvent this problem, we are matching the locations of pre-stellar cores with locations of bright background galaxies from the Very Large Array Sky Survey (VLASS) that can backlight these cores and provide absorption line observations along a narrow line-of-sight.

Initially, we focused on the locations of pre-stellar cores in the Taurus and Cepheus molecular clouds identified by the Herschel Gould Belt Survey Archive. Using data from the VLASS, we looked for large, bright, compact objects, namely galaxies, that matched locations of the pre-stellar cores in the Herschel Gould Belt Survey. Through visual analysis, we identified several candidates for background sources that match the location of pre-stellar cores. HI has been observed globally in molecular clouds and pre-stellar cores at ~3" resolution as a narrow line absorption feature against bright, extended HI background emission (HINSA). OH is typically observed as a weak emission line and no single dish observations resolve the OH emission toward pre-stellar cores. We propose to use the VLA to observe these "best" candidates in spectral lines of HI and OH to determine the column density along "pencil-beam" lines-of-sight to compare with global measurements from a single dish telescope.

Hannah Gruber (University of Arizona)

Abstract: We present circumstellar analysis of oxygen-rich (M-type) Mira variables. These highly evolved low-to-intermediate mass stars are characterized by their efficient dust and molecule production, making them excellent laboratories for studying enrichment processes within circumstellar environments (CSEs). We combine mid-IR spectral analysis from the Spitzer Infrared Spectrograph (IRS) with interferometric measurements taken with the Palomar Testbed Interferometer (PTI) to provide unprecedented access to dust and molecule production region of M-type atmospheres.

In the Spitzer spectra we have identified several ro-vibrational Q-branch bandheads of CO2 that are not observable with ground based instruments because telluric features dominate at these wavelengths. These features exhibit dynamic behavior that is likely tied to the pulsational nature of the atmosphere. We adapted the radiative transfer code RADEX for use at wavelengths between 10-20 μm to model these features. The RADEX models provide physical characteristics of the gas such as kinetic temperature, density, and optical depth. Meanwhile, we have ~10 years of interferometric measurements taken with PTI that when combined with parallax distances to the stars provide a direct measurement of the radial size of the star (among other fundamental parameters). Combining the physical size of the star with RADEX models determines the emitting region of the gas, allowing us to fully characterize the gas in the circumstellar environment. This approach has led us to observational evidence of a "refrigeration zone" between 2-5 R★ where the temperature radically departs from equilibrium predictions, which can have profound impact on dust formation.

Dana K. Baylis-Aguirre (NMT)
8. Withdrawn

Abstract: Stellar modeling is still mostly done through hydrostatic, one-dimensional models. Yet observations, in particular asteroseismology, and multidimensional simulations clearly show that this picture is insufficient. Modern high-performance computing and advances in numerical methods allow us to open a new window into the interior of stars.

In this contribution we show the challenges in stellar hydrodynamics simulations and how we solve them using new methods from the applied mathematics community. We apply these to core and shell convection in stars to study mixing at boundaries and the generation of internal gravity waves. We also use these simulations to make inferences on the observed asteroseismological signal and to study chemical mixing caused by waves.

Philipp V. F. Edelmann (LANL)

Abstract: We present evidence for a strong pulsar candidate and the detection of radio transients in the stellar cluster Glimpse C01. Using images from the VLA Low-band Ionosphere and Transient Experiment (VLITE) centered at a frequency of 340 MHz, we searched 94 globular clusters for steep spectrum radio sources. We cross-correlated with several radio sky surveys including VLASS to further analyze the sources and to calculate spectral indices. We identified a strong pulsar candidate with a steep spectral index (alpha ~ -2.7), which is well within the expected range for pulsars. There is ongoing debate about the classification of Glimpse C01, and confirming that a pulsar is present in the cluster is especially important because it will provide insight on the age of the cluster. In addition, it demonstrates that searches for steep spectrum sources as pulsar candidates are effective in areas of high dispersion. We also observed transient radio emission following the X-ray outburst MAXI J1848-015. This has been identified with a black hole in the center of the cluster; if associated, then the radio emission may be caused by jets from the black hole that appeared within a year of the X-ray outburst.

Amaris McCarver (TTU)

Abstract: In an X-ray binary, a spin-orbit misalignment is an angular momenta misalignment between the binary orbit and the black hole (BH). Conventional theory predicts that the rotational axis of the X-ray emitting inner disk regions aligns with the BH spin axis, as does the jet axis. Therefore, measuring the orientation of the inner disk (or jet) probes the BH spin orientation. Our goal is to robustly measure the inner disk inclination angle in GRO J1655-40, whose jet and orbital inclinations are known.We reduce X-ray data from five Swift/XRT observations of GRO J1655-40 in the high/soft state, which are contaminated by photon pile-up and dust-scattering halos. To eliminate these effects, we develop an analysis pipeline that extracts the appropriate region of the point spread function and models the dust-scattered emission. By repurposing the disk continuum fitting technique, typically used to measure BH spin, we measure the inner disk inclination angle. This allows us to test the expectation of disk-jet alignment and independently verify the spin-orbit misalignment in GRO J1655-40. Our work offers an important step toward understanding the 3D orientations of spinning BHs.

Zuzana Turonova (LANL, Silesian University in Opava)

Abstract: The merger of two galaxies, each hosting a supermassive black hole (SMBH) of mass 10^6 M_sun or more, could yield a bound SMBH binary. For the early-type galaxy NGC4472, we study how astrometry with a next-generation Very Large Array (ngVLA) could be used to monitor the reflex motion of the primary SMBH of mass M_pri, as it is tugged on by the secondary SMBH of mass M_sec. Casting the orbit of the putative SMBH binary in terms of its period P, semimajor axis a_bin, and mass ratio q = M_sec / M_pri < 1, we find the following: (1) Orbits with fiducial periods of P = 4 yr and 40 yr could be spatially resolved and monitored. (2) For a 95% accuracy of 2 microas per monitoring epoch, sub-parsec values of a_bin could be accessed over a range of mass ratios notionally encompassing major (q > 1/4) and minor (q < 1/4) galaxy mergers. (3) If no reflex motion is detected for M_pri after 1(10) yr of monitoring, a SMBH binary with period P = 4(40) yr and mass ratio q > 0.01(0.003) could be excluded. This would suggest no present-day evidence for a past major merger like that recently simulated, where scouring by a q ~ 1 SMBH binary formed a stellar core with kinematic traits like those of NGC4472. (4) Astrometric monitoring could independently check the upper limits on q from searches for continuous gravitational waves from NGC4472.

Joan Wrobel (NRAO)

Abstract: Approximately one-third of existing γ-ray sources identified by the Fermi Gamma-Ray Space Telescope are considered to be unassociated, with no known counterpart at other frequencies/wavelengths. These sources have been the subject of intense scrutiny and observational effort during the observatory's mission lifetime, and here we present a method of leveraging existing radio catalogs to examine these sources without the need for specific dedicated observations, which can be costly and complex. Via the inclusion of many sensitive low-frequency catalogs we specifically target steep spectrum sources such as pulsars. This work has found steep-spectrum radio sources contained inside 591 Fermi unassociated fields, with at least 21 of them being notable for having pulsar-like γ-ray properties as well. We also identify a number of other fields of interest based on various radio and γ-ray selections.

Seth Bruzewski (UNM)
14. Withdrawn

Abstract: Radio Frequency Interference (RFI) can impact astronomical measurements when radio signals produced by man-made devices, such as cell phones and satellites, interfere with sensitive instrumentation. Instruments that are especially vulnerable to RFI can be placed in radio-quiet or `dark` sites, typically remote areas where transmissions are restricted to protect instrumentation from interference. RFI can be a problem for Cosmic Microwave Background (CMB) experiments, as their technology makes them sensitive to a broad range of frequencies. As more commercial satellites are launched and as portable consumer electronic devices utilize an increasingly broad range of the electromagnetic spectrum, the prevalence of RFI may be increasing, even at remote radio-quiet sites. We analyzed publicly available data collected by a dedicated RFI monitor operated by the BICEP/Keck team alongside their CMB survey instruments. This RFI monitor has run almost continuously in the South Pole`s Dark Sector since 2014, which provides a long and comprehensive record of RFI to study its prevalence by season and over time. Understanding long-term trends in the prevalence of RFI can help understand its impact on survey sensitivity and inform future mitigation efforts.

Simon Matin (UNM)

Abstract: The Very Large Array Sky Survey (VLASS) will observe ~80% of the sky (Declination > -40deg) over three epochs (split into 6 total observing cycles over 7 years) producing full polarization, high angular resolution data between 2-4 GHz. Each epoch will generate 35,500 sets of image products, where each set of products covers approximately 1 square degree of sky. During past observation cycles, a quality assurance (QA) process was manually applied to each dataset before it was released to the community as a set of Quick-Look (QL) calibrated data and image products. The manual process of QL imaging QA required an individual to examine each image, which was time consuming and the repetitive nature was prone to random human error. Automation strategies are currently being investigated to alleviate these bottlenecks in production. This approach includes using Convolutional Neural Networks and/or heuristic based methodologies to detect artifacts such as Radio Frequency Interference, Primary Beam Holes, and High Weights in the images. Implementing automation into the QL workflow will reduce the number of manually QAed QL images by at least 80% and allow for a faster delivery of QL image products. The methods developed from automating QL imaging QA will provide a foundation for applying automation to the general VLASS QA process for other image products.

Karlee Radford (NRAO)

Abstract: Operating since 1993 the Very Long Baseline Array (VLBA) has been a workhorse in radio astronomy, providing a dedicated year-round very long baseline interferometry (VLBI) array with baselines ranging from 200-8000 km. The VLBA is currently undergoing a series of electronic upgrades (Digital Backend, GPS Timing, Real-time System) which will replace aging components, increase the reliability of the instrument, and finally to enhance capabilities of the array. These upgrades will also provide opportunities for research into better ways to observe, calibrate, and reduce VLBI data. The goal of this poster is to inform the community about these upgrades and what they can expect to see in the near future.

Steven Tremblay (NRAO)

Abstract: The origin of the cosmic diffuse gamma-ray (CDG) background in the 0.3 – 10 MeV energy range is a mystery that has persisted for over 40 years. The best existing measurements have large systematic uncertainties, and the latest theoretical models based on emission from active galactic nuclei and supernovae differ significantly from these data below 1 MeV. The Mini Astrophysical MeV Background Observatory (MAMBO) is a new CubeSat mission under development at Los Alamos National Laboratory with the goal of making high-quality measurements of the MeV CDG. The concept is motivated by the fact that, since the MeV CDG is relatively bright, only a small detector is required to make high-quality measurements of it. Indeed, the sensitivity of space-based gamma-ray instruments to the CDG is limited not by size, but by the locally generated instrumental background produced by interactions of energetic particles in spacecraft materials. Comparatively tiny CubeSat platforms provide a uniquely quiet environment relative to previous gamma-ray science missions. The MAMBO mission will provide the best measurements ever made of the MeV CDG spectrum and angular distribution, utilizing two key innovations: 1) low instrumental background on a 12U CubeSat platform; and 2) an innovative shielded spectrometer design that simultaneously measures signal and background. Los Alamos is partnering with commercial vendors for the 12U CubeSat bus and ground station network, which we expect will become a new paradigm for low-cost, fast-turnaround space science missions. We describe the MAMBO instrument and mission concept in detail and present the expected scientific return.

Peter Bloser (LANL)

Abstract: For amateur astronomers, getting useful science out of their observations is not straightforward due to inaccessibility of tools. Only after probing into the depths of the scientific community do methods of conducting practical science come to light. Our goal is to develop an easily accessible program dedicated for night sky observation with a specialization in asteroid tracking. This will include automatic data processing and detail the procedural guidelines on efficient search methods. While building the groundwork for this project, we have determined the inefficiency that lies within manually searching for near-earth asteroids. We have experimented with manual image correction and panorama stitching, a technique that an average amateur astronomer would use uninstructed. As a solution, we have written a code that can automatically process data for use in building composite images to search for any anomalous motion in astronomical pictures. The expected timeframe for the analysis of the night sky will be radically reduced through this program. Because of this, aspiring astronomers can make their own discoveries. We are pursuing to utilize newer resources more accessible to the public. With this program, faster image processing and more efficient data collection for the amateur astronomer could be a tangible reality.

Nathaniel Serda (NMT)

Abstract: Since the advent of space-based photometric missions, thousands of new stellar oscillators have been observed with unprecedented precision, motivating changes to our understanding of oscillation driving mechanisms, interior physical processes, and stellar models. In order to refine our models of stellar structure and evolution, we need well-constrained stellar pulsators to study. Kepler binary star systems are ideal testbeds as the constraints of binarity provide precise derived stellar parameters and the high frequency resolution of continuous observations allows for detailed analysis of stellar oscillations. Studies of Kepler pulsating binaries thus far have provided robust constraints on stellar models, but the current sample is limited in size and biased in parameter space.

This project will expand the sample of Kepler pulsating binaries by identifying Kepler targets that display frequency signatures of two distinct stars but no photometric signs of binarity. Using spectroscopic observations to detect orbital motion, additional systems that were previously "hidden," or non-eclipsing, can be identified. 21 Kepler red giants that displayed signatures of solar-like and classical oscillations were considered as potential pulsating hidden binaries. Using the ARCES spectrograph on the 3.5-meter telescope at Apache Point Observatory, 17 of these targets have been observed multiple times. Through the detection of Doppler shifted lines and the derivation of radial velocities, our observations have confirmed 14 of these targets as spectroscopic binaries. With ample observations to provide sufficient phase coverage, dynamical modeling of the binary star systems will be performed to provide constraints on the component stellar pulsators.

Anne Hedlund (LANL/NMSU)

Abstract: From 2009 to 2013, the NASA Kepler spacecraft obtained 30-minute cadence high-precision photometric data on stars in a 200 x 200 pixel (4 arcsec/pixel) ‘superstamp’ field centered on the 2.4 billion-year-old star cluster NGC 6819. We analyzed the photometric data to identify delta Scuti and gamma Doradus pulsating variables. These stars are on or near the main sequence, have masses 1.4 to 2 solar masses, and pulsate in multiple radial and nonradial modes. For nine stars, we found many (20 to over 200) significant frequencies. Four confirmed cluster members are ‘blue stragglers’, i.e., they are still on the main sequence above the cluster turnoff but should have already left the main sequence to become red giants. The observed frequencies can be used to determine properties of the stars that are difficult to obtain in any other way. For example, the average frequency separations of delta Scuti stars can be used to determine their mean densities, and, in conjunction with effective temperature, surface gravity, and luminosity, to derive their masses. The slopes of period-spacing sequences for gamma Doradus variables can be used to determine their near-core rotation rates. We present our findings and implications for the formation and evolution of these stars, particularly for the NGC 6819 blue stragglers.

Joyce A. Guzik (LANL)

Abstract: We present preliminary results from a study on UCHII region G10.47+0.03 using a plethora of Ammonia inversion transitions. This study visits typical optically thin and optically thick approximation approaches for determining density, kinetic temperature and environmental conditions. This study provides new approaches to describing the environment around Hot Molecular Cores by analyzing the spectral contribution from nonmetastable transitions instead of the traditional metastable approaches. We present maps, spectra and rotation diagrams using a variety of new methods to combine results from the assortment of ammonia inversion transitions.

James Price (NMT)

Abstract: As astronomy gains more access to exceptionally large amounts of data through all sky surveys and publicly available data there is a need to review data with greater efficiency. One approach to solve such problem in big data is to use machine learning algorithms that can achieve accurate results much faster than any one person. We propose an unsupervised learning method to find blazar candidates utilizing agglomerative hierarchical clustering. Using cross-matched data from Sloan Digital Sky Survey 16th data release (SDSS DR16), the second ROSAT All Sky Survey , the AllWISE Data Release and VLASS QL Ep.1 Catalog we obtain a high-dimension feature space in which unsupervised learning is useful for finding similarities between objects. After our machine learning clusters have been obtained, we cross-matched them with the Blazar Radio and Optical Survey (BROS) catalog to identify the machine learning cluster with the highest percentage of blazars. We obtain a machine learning cluster with approximately 55% of blazars and blazar candidates identified in BROS. The remaining machine learning cluster members can be viewed as blazar candidates. These blazar candidates could be followed up with VLBA observations to determine whether they can help provide new calibrator candidates that can assist in the ngVLA era.

John Morales (TTU)

Last updated on 17 February 2023 by Anna D. Kapinska.