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NASA NTRS2021

Time series comparisons in Deep Space Network

The Deep Space Network (DSN) is NASA’s international array of antennas that support interplanetary spacecraft missions. DSN provides radar and radio astronomy observations that enhance our understanding of the solar system and the larger universe. A track is a block of continuous multi-dimensional time series from the beginning to end of DSN communication with the target spacecraft, containing 129 monitor data items lasting several hours at a frequency of 0.2-1Hz. Monitor data on each track reports on the performance of specific spacecraft operations and the DSN itself. DSN is receiving signals from 32 spacecraft across the solar system. DSN has pressure to reduce costs while maintaining the quality of support for DSN mission users. DSN operators need to simultaneously monitor multiple tracks and identify anomalies in real time. DSN has seen that as the number of missions increases, the data that needs to be processed increases over time. In this project, we look at the last 8 years of data for analysis. Any anomaly in the track indicates a problem with either the spacecraft, DSN equipment, or weather conditions. DSN operators typically write “discrepancy reports” for further analysis. It is recognized that it would be quite helpful to identify 10 similar historical tracks out of the huge database to quickly find/match anomalies. This tool has three functions: (1) identification of the top 10 similar historical tracks, (2) detection of anomalies compared to the reference normal track, and (3) comparison of statistical differences between two given tracks. The requirements for these features were confirmed by survey responses from 21 DSN operators and engineers. The preliminary machine learning model has shown promising performance (AUC=0.92). We plan to increase the number of data sets and perform additional testing to improve performance further before its planned integration into the Track Visualizer to assist DSN field operators and engineers.

Rebbapragada, Umaa↗

DOE OSTI2020

New Grids of Pure-hydrogen White Dwarf NLTE Model Atmospheres and the HST/STIS Flux Calibration

Nonlocal thermodynamic equilibrium (NLTE) calculations of hot white dwarf (WD) model atmospheres are the cornerstone of modern flux calibrations for the Hubble Space Telescope and for the CALSPEC database. These theoretical spectral energy distributions (SEDs) provide the relative flux versus wavelength, and only the absolute flux level remains to be set by reconciling the measured absolute flux of Vega in the visible with the Midcourse Space Experiment values for Sirius in the mid-IR. The most recent SEDs calculated by the tlusty and tmap NLTE model atmosphere codes for the primary WDs G191-B2B, GD 153, and GD 71 show improved agreement to 1% from 1500 Å to 30 μm, in comparison to the previous 1% consistency only from 2000 Å to 5 μm. These new NLTE models of hot WDs now provide consistent flux standards from the far UV to the mid-IR.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2023

Does Feedback from Supermassive Black Holes Coevolve with the Host in Type 2 Quasars?

The feedback from the accretion of central supermassive black holes (SMBHs) is a hot topic in the coevolution of SMBHs and their host galaxies. By tracing the large-scale outflow using the line profile and bulk velocity shift of [O III ]λ5007, the evolutionary role of outflow is studied here on a large sample of 221 type 2 quasars (QSO2s) extracted from Reyes et al. By following our previous study on local Seyfert 2 galaxies, the current spectral analysis on the Sloan Digital Sky Survey spectroscopic database enables us to arrive at the following results: (1) by using the Lick indices, we confirm that QSO2s are, on average, more frequently associated with younger stellar populations than Seyfert galaxies; (2) QSO2s with a stronger outflow tend to be associated with a younger stellar population, which implies a coevolution between the feedback from SMBHs and the host in QSO2s; (3) although occupied at the high L bol /L Edd end, the QSO2s follow the L bol /L Edd -D n (4000) sequence established from local, less-luminous Seyfert galaxies, which suggests a decrease of the accretion activity of SMBHs and also of feedback as the circumnuclear stellar population continuously ages.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2020

High-resolution Spectra of Earth-like Planets Orbiting Red Giant Host Stars

In the near future we will have ground- and space-based telescopes that are designed to observe and characterize Earth-like planets. While attention is focused on exoplanets orbiting main-sequence stars, more than 150 exoplanets have already been detected orbiting red giants, opening the intriguing question of what rocky worlds orbiting in the habitable zone (HZ) of red giants would be like and how to characterize them. We present a high-resolution spectral database of reflection and emission spectra for nominal Earth-like planets orbiting in the red giant HZ from the visible to infrared (0.4–20 μm) for planets orbiting at the Earth-equivalent distance. We also show the change of such planetary spectra through the evolution of their red giant hosts. While the luminosity of the host increases the contrast ratio between star and planet, the increased orbital distance of the HZ for red giant hosts relaxes the light suppression requirements close to the star, which could make such planets interesting targets to characterize and search for signs of life, if new coronagraph designs with higher suppression at larger orbital separations could be developed. We assess the feasibility of characterizing atmospheric features including biosignatures for such planets with the proposed mission concept Large UV/Optical/IR Surveyor (LUVOIR).

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS2012

From EXOSAT to the High Energy Astrophysics Science Archive (HEASARC): X-ray Astronomy Comes of Age

In May 1983 the European Space Agency launched EXOSAT, its first X-ray astronomy observatory. Even though it lasted only 3 short years, this mission brought not only new capabilities that resulted in unexpected discoveries, but also a pioneering approach to operations and archiving that changed X-ray astronomy from observations led by small instrument teams, to an observatory approach open to the entire community through a guest observer program. The community use of the observatory was supported by a small dedicated team of scientists, the precursor to the data center activities created to support e.g. Chandra and XMM-Newton. The new science capabilities of EX OS AT included a 90 hr highly eccentric high earth orbit that allow unprecedented continuous coverage of sources as well as direct communication with the satellite that allowed real time decisions to respond to unexpected events through targets of opportunity. The advantages of this orbit demonstrated by EXOSAT resulted in Chandra and XMM-Newton selecting similar orbits. The three instruments on board the EXOSAT observatory were complementary, designed to give complete coverage over a wide energy band pass of 0.05-50 keY. An onboard processor could be programmed to give multiple data modes that could be optimized in response to science discoveries: These new capabilities resulted in many new discoveries including the first comprehensive study of AGN variability, new orbital periods in X-ray binaries and cataclysmic variables, new black holes, quasi-periodic oscillations from neutron stars and black holes and broad band X-ray spectroscopy. The EXOSAT team generated a well-organized database accessible worldwide over the nascent internet, allowing remote selection of data products, making samples and undertaking surveys from the data. The HEASARC was established by NASA at Goddard Space Flight Center in 1990 as the repository of NASA X-ray and Gamma-ray data. The proven EXOSAT database system became the core of the HEASARC infrastructure. The HEASARC pioneered many concepts now taken for granted including standardized formats using FITS files, restoring data from earlier missions, multi-mission analysis tools and a searchable archive over the world wide web.

White, Nicholas E.↗

DOE OSTI2023

Powerful Radio Sources in the Southern Sky. I. Optical Identifications

Since the early sixties, our view of radio galaxies and quasars has been drastically shaped by discoveries made thanks to observations of radio sources listed in the Third Cambridge Catalog and its revised version (3CR). However, the largest fraction of data collected to date on 3CR sources was performed with relatively old instruments, rarely repeated and/or updated. Importantly, the 3CR contains only objects located in the Northern Hemisphere, thus having limited access to new and innovative astronomical facilities. To mitigate these limitations, we present a new catalog of powerful radio sources visible from the Southern Hemisphere, extracted from the GLEAM 4 Jy (G4Jy) catalog and based on equivalent selection criteria as the 3CR. This new catalog, named G4Jy-3CRE, where the E stands for “equivalent,” lists a total of 264 sources at decl. below -5° and with 9 Jy limiting sensitivity at ~178 MHz. We explored archival radio maps obtained with different surveys and compared them with optical images available in the Pan-STARRS, DES, and DSS databases to search for optical counterparts of their radio cores. We compared mid-infrared counterparts, originally associated in the G4Jy, with the optical ones identified here, and we present results of a vast literature search carried out to collect redshift estimates for all G4Jy-3CRE sources resulting in a total of 145 reliable z measurements.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2023

Continuous Filament Network of the Local Universe

Simulated galaxy distributions are suitable for developing filament detection algorithms. However, samples of observed galaxies, being of limited size, cause difficulties that lead to a discontinuous distribution of filaments. We created a new galaxy filament catalog composed of a continuous cosmic web with no lone filaments. The core of our approach is a ridge filter used within the framework of image analysis. We considered galaxies from the HyperLeda database with redshifts 0.02 ≤ z ≤ 0.1, and in the solid angle 120° ≤ R.A. ≤ 240°, 0° ≤ decl. ≤ 60°. We divided the sample into 16 two-dimensional celestial projections with redshift bin Δ z = 0.005, and compared our continuous filament network with a similar recent catalog covering the same region of the sky. We tested our catalog on two application scenarios. First, we compared the distributions of the distances to the nearest filament of various astrophysical sources (Seyfert galaxies and other active galactic nuclei, radio galaxies, low-surface-brightness galaxies, and dwarf galaxies), and found that all source types trace the filaments well, with no systematic differences. Next, among the HyperLeda galaxies, we investigated the dependence of the g - r color distribution on the distance to the nearest filament, and confirmed that early-type galaxies are located on average further from the filaments than late-type ones.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS2006

Overview of the Solar-B Mission

The Solar-B mission is a collaboration between the Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, the National Aeronautics and Space Administration (NASA) and the Particle Physics and Astronomy Research Council (PPARC) of the United Kingdom and the European Space Agency. The principal scientific goals of the mission are to understand the processes of magnetic field generation, transport and ultimate dissipation of solar magnetic fields and how the release of magnetic energy is responsible for the heating and structuring of the chromosphere and corona. The scientific payload consists of three instruments: the Solar Optical Telescope that consists of the Optical Telescope Assembly and the Focal Plane Package (FPP), the X-ray Telescope and the EUV Imaging Spectrometer Each instrument is a result of the combined talents of all the members of the international team and their design and performance is described in separate papers in this session. The instruments are designed to work together as an 'observatory' simultaneously studying the target, at which the spacecraft is pointed, at different levels in the atmosphere. The spacecraft is scheduled for launch in September 2006 from the Uchinoura Space Center into a 600 km circular, sun-synchronous, polar orbit with a nominal elevation of 97.9 degrees. The orbit provides at least two morning and two evening contacts in Japan. Morning contacts are used for recovering quick look science data and the evening contacts for uploading commands. In addition ESA will provide 15 contacts per day from the Norwegian high latitude (78deg 14' N) ground station at Svalbard. The data downloads are transmitted to the ISAS Sirius database. They will be reformatted into FITS files and archived as Level 0 data on the ISAS DARTS system and made available to the scientific community. Scientific operations will be conducted from the IS AS facility located in Sagamihara, Japan. They are separated into planning, implementation and archiving. The planning process involves monthly, weekly and daily planning meetings. All scientific data will be made available after the first six month approximately one week after its collection.

Davis, John M.↗

DOE OSTI2020

The Stellar Velocity Distribution Function in the Milky Way Galaxy

The stellar velocity distribution function in the solar vicinity is reexamined using data from the Sloan Digital Sky Survey Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey’s DR16 and Gaia DR2. By exploiting APOGEE’s ability to chemically discriminate with great reliability the thin-disk, thick-disk, and (accreted) halo populations, we can, for the first time, derive the three-dimensional velocity distribution functions (DFs) for these chemically separated populations. We employ this smaller but more data-rich APOGEE+Gaia sample to build a data-driven model of the local stellar population velocity DFs and use these as basis vectors for assessing the relative density proportions of these populations over the 5 < R < 12 kpc and −1.5 < z < 2.5 kpc range as derived from the larger, more complete (i.e., all-sky, magnitude-limited) Gaia database. We find that 81.9% ± 3.1% of the objects in the selected Gaia data set are thin-disk stars, 16.6% ± 3.2% are thick-disk stars, and 1.5% ± 0.1% belong to the Milky Way stellar halo. We also find the local thick-to-thin-disk density normalization to be ρ {sub T}(R {sub ⊙})/ρ {sub t}(R {sub ⊙}) = 2.1% ± 0.2%, a result consistent with, but determined in a completely different way from, typical star-count/density analyses. Using the same methodology, the local halo-to-disk-density normalization is found to be ρ {sub H}(R {sub ⊙})/(ρ {sub T}(R {sub ⊙}) + ρ {sub t}(R {sub ⊙})) = 1.2% ± 0.6%, a value that may be inflated due to the chemical overlap of halo and metal-weak thick-disk stars.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS2018

The Apollo Sample Suite: 50 Years of Solar System Insight

The Apollo program was undoubtable a crowning achievement in human history. In addition to the obvious cultural significance, scientific results from the Apollo program had a lasting impression on a range of scientific fields, none more so that the effect the samples had on the fields of geology and cosmochemistry. The six Apollo missions collected 382 kg of rock, regolith, and core samples from geologically diverse locations on the Moon. In the nearly 50 years since the first samples were returned, there have been over 3000 different requests for samples, each yielding insights into fields as disparate as biology, medicine, astronomy, engineering, material science, and of course geology. Early studies of the Apollo samples revealed primary insights into the origin and evolution of the Moon, and of the Earth-Moon system, but the results also had implications for bodies throughout the solar system, e.g., defining crater counting rates. Over the decades, continued study of the Apollo samples by new generations of scientists using new instruments have continued to yield significant new discoveries, including the presence of endogenous water in the Moon and the possible presence of a lunar cataclysm, that in turn has contributed to new models of solar system formation and evolution. The Apollo samples have often been used as a proxy for studying other bodies like Mercury or asteroids. The Apollo samples have also directly contributed to the interpretation of remotely sensed data sets, including their use as ground truth for both Clementine and Lunar Prospector global geochemical maps. Despite the Apollo samples being a static collection, recent efforts will ensure that investigators continue to have access to new samples. For example, there was a recent solicitation for study of previously unopened Apollo samples in vacuum-sealed containers, as well as new access to samples stored frozen or in a He atmosphere. Similarly, the use of X-ray computed tomography as part of the curation process is identifying new clasts within polymict breccias that are available for study. Finally, the MoonDB project is putting all previously published lunar geochemical analyses into a searchable database, which should facilitate new investigations.

Zeigler, Ryan↗

DOE OSTI2023

Carbon-enhanced metal-poor star candidates from BP/RP spectra in Gaia DR3

ABSTRACT Carbon-enhanced metal-poor (CEMP) stars comprise almost a third of stars with [Fe/H] < −2, although their origins are still poorly understood. It is highly likely that one sub-class (CEMP-s stars) is tied to mass-transfer events in binary stars, while another sub-class (CEMP-no stars) are enriched by the nucleosynthetic yields of the first generations of stars. Previous studies of CEMP stars have primarily concentrated on the Galactic halo, but more recently they have also been detected in the thick disc and bulge components of the Milky Way. Gaia DR3 has provided an unprecedented sample of over 200 million low-resolution (R ≈ 50) spectra from the BP and RP photometers. Training on the CEMP catalogue from the SDSS/SEGUE database, we use XGBoost to identify the largest all-sky sample of CEMP candidate stars to date. In total, we find 58 872 CEMP star candidates, with an estimated contamination rate of 12 per cent. When comparing to literature high-resolution catalogues, we positively identify 60–68 per cent of the CEMP stars in the data, validating our results and indicating a high completeness rate. Our final catalogue of CEMP candidates spans from the inner to outer Milky Way, with distances as close as r ∼ 0.8 kpc from the Galactic centre, and as far as r > 30 kpc. Future higher resolution spectroscopic follow-up of these candidates will provide validations of their classification and enable investigations of the frequency of CEMP-s and CEMP-no stars throughout the Galaxy, to further constrain the nature of their progenitors.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS2020

The XRISM Science Data Center: Optimizing the Scientific Return from a Unique X-ray Observatory

The X-Ray Imaging and Spectroscopy Mission, XRISM, is currently scheduled to launch in 2022 with the objective of building on the brief, but significant, successes of the ASTRO-H (Hitomi) mission in solving outstanding astrophysical questions using high resolution X-ray spectroscopy. The XRISM Science Operations Team (SOT) consists of the JAXA-led Science Operations Center (SOC) and NASA-led Science Data Center (SDC), which work together to optimize the scientific output from the Resolve high-resolution spectrometer and the Xtend wide-field imager through planning and scheduling of observations, processing and distribution of data, development and distribution of software tools and the calibration database (CaldB), support of ground and in-flight calibration, and support of XRISM users in their scientific investigations of the energetic universe. Here, we summarize the roles and responsibilities of the SDC and its current status and future plans. The Resolve instrument poses particular challenges due to its unprecedented combination of high spectral resolution and throughput, broad spectral coverage, and relatively small field-of-view and large pixel-size. We highlight those challenges and how they are being met.

XRISM↗

DOE OSTI2021

A Deep Study of an Intermediate-age Open Cluster SAI 35 (Juchert 20) Using Ground-based Imaging and Gaia EDR3 Astrometry

We present a CCD UBVI photometric study of poorly studied intermediate-age open cluster SAI 35 (Juchert 20) for the first time. To accomplish this study, we also used LAMOST DR5, Two Micron All Sky Survey, and Gaia EDR3 databases. We identified 214 most probable cluster members with membership probability higher than 50%. The mean proper motion of the cluster is found as μ{sub α}cos δ=1.10±0.01 and μ {sub δ} = −1.66 ± 0.01 mas yr{sup −1}. We find the normal interstellar extinction law using the various two-color diagrams. The age, distance, reddening, and radial velocity of the cluster are estimated to be 360 ± 40 Myr, 2.9 ± 0.15 kpc, 0.72 ± 0.05 mag, and −91.62 ± 6.39 km s{sup −1}, respectively. The overall mass function slope for main-sequence stars is found to be 1.49 ± 0.16 within the mass range 1.1–3.1 M {sub ⊙}, which is in agreement with Salpeter’s value within uncertainty. The present study demonstrates that SAI 35 is dynamically relaxed. Galactic orbital parameters are determined using Galactic potential models. We found that this object follows a circular path around the Galactic center.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2024

Rotational state-to-state transition rate coefficients for H 2 O + H 2 O collisions at nonequilibrium conditions

Aims.The goal is to develop a database of rate coefficients for rotational state-to-state transitions in H 2 O + H 2 O collisions that is suitable for the modeling of energy transfer in nonequilibrium conditions, in which the distribution of rotational states of H 2 O deviates from local thermodynamic equilibrium. Methods.A two-temperature model was employed that assumed that although there is no equilibrium between all possible degrees of freedom in the system, the translational and rotational degrees of freedom can be expected to achieve their own equilibria independently, and that they can be approximately characterized by Boltzmann distributions at two different temperatures,T kin andT rot . Results.Upon introducing our new parameterization of the collisional rates, taking into account their dependence on bothT kin andT rot , we find a change of up to 20% in the H 2 O rotational level populations for both ortho and para-H 2 O for the part of the cometary coma where the nonequilibrium regime occurs.

Astronomy & Astrophysics↗

DOE OSTI2023

First measurement of polarisation transfer $C$$^{n}_{x'}$ in deuteron photodisintegration

A first measurement of the polarisation transfer from a circularly-polarised photon to the final state neutron ($C$$^{n}_{x'}$) in deuterium photodisintegration has been carried out. This quantity is determined over the photon energy range 370 – 700 MeV and for neutron centre-of-mass breakup angles ~ 45 – 120°. The polarisation of the final state neutrons was determined by an ancillary large-acceptance nucleon polarimeter, surrounding a cryogenic liquid deuterium target within the Crystal Ball detector at MAMI. The polarimeter characterised (n, p) charge exchange of the ejected neutrons to determine their polarisation. The new $C$$^{n}_{x'}$ data are also compared to a theoretical model based on nucleonic and nucleon resonance degrees of freedom constrained by the current world-database of deuterium photodisintegration measurements. Structures in $C$$^{n}_{x'}$ observed in the region of the d*(2380) could not be explained by conventional models of deuteron photodisintegration.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2023

Searching in H I for Massive Low Surface Brightness Galaxies: Samples from HyperLeda and the UGC

A search has been made for 21 cm H I line emission in a total of 350 unique galaxies from two samples whose optical properties indicate they may be massive. The first consists of 241 low surface brightness (LSB) galaxies of morphological type Sb and later selected from the HyperLeda database and the second consists of 119 LSB galaxies from the UGC with morphological types Sd-m and later. Of the 350 unique galaxies, 239 were observed at the Nançay Radio Telescope, 161 at the Green Bank Telescope, and 66 at the Arecibo telescope. A total of 295 (84.3%) were detected, of which 253 (72.3%) appear to be uncontaminated by any other galaxies within the telescope beam. Finally, of the total detected, uncontaminated galaxies, at least 31 appear to be massive LSB galaxies, with a total H I mass ≥ 10 10 M ⊙ , for H 0 = 70 kms -1 Mpc -1 . If we expand the definition to also include galaxies with significant total (rather than just gas) mass, i.e., those with an inclination-corrected H I line width W 50,cor > 500 km s -1 , this brings the total number of massive LSB galaxies to 41. There are no obvious trends between the various measured global galaxy properties, particularly between mean surface brightness and galaxy mass.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2021

The Most Massive White Dwarfs in the Solar Neighborhood

We present an analysis of the most massive white dwarf candidates in the Montreal White Dwarf Database 100 pc sample. We identify 25 objects that would be more massive than 1.3M ⊙ if they had pure H atmospheres and CO cores, including two outliers with unusually high photometric mass estimates near the Chandrasekhar limit. We provide follow-up spectroscopy of these two white dwarfs and show that they are indeed significantly below this limit. We expand our model calculations for CO core white dwarfs up to M = 1.334 M ⊙ , which corresponds to the high-density limit of our equation-of-state tables, ρ = 109 g cm -3 . We find many objects close to this maximum mass of our CO core models. A significant fraction of ultramassive white dwarfs are predicted to form through binary mergers. Merger populations can reveal themselves through their kinematics, magnetism, or rapid rotation rates. We identify four outliers in transverse velocity, four likely magnetic white dwarfs (one of which is also an outlier in transverse velocity), and one with rapid rotation, indicating that at least 8 of the 25 ultramassive white dwarfs in our sample are likely merger products.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2020

Utilizing a Database of Simulated Geometric Albedo Spectra for Photometric Characterization of Rocky Exoplanet Atmospheres

In anticipation of future flagship missions focused on the goal of achieving direct imaging of rocky exoplanets, we have developed a database of models to help the community examine the potential spectral characteristics of a broad range of rocky planet atmospheres. Using the publicly available Planetary Spectrum Generator, we have computed a grid of 141,600 rocky exoplanet geometric albedo spectra across a seven-dimensional parameter space. Using this grid, we have performed a color–color analysis seeking to identify the most useful near-UV and red or near-infrared photometric follow-up channels to combine with a green-optical (discovery) spectral channel. We found that a combination of filters at 0.4, 0.58, and ∼0.8 μm were able to distinguish between atmospheres with moderate-to-high concentrations of four different dominant absorbing constituents, given at least 10 hr of observation on a star at 10 parsec with a 15 m class space telescope; however, more moderate abundances similar to those of solar system rocky bodies would be more challenging to detect. We recommend that future missions seeking to characterize directly imaged rocky exoplanets by colors alone further consider multiband photometry as a first discriminator for planetary characteristics.

79 ASTRONOMY AND ASTROPHYSICS↗