UMBC Center for Space Sciences and Technology (CSST) / Center for Research and Exploration in Space Sciences & Technology II (CRSST II)

Permanent URI for this collectionhttp://hdl.handle.net/11603/7798

The Center for Space Sciences and Technology (CSST) is the administrative unit for UMBC’s participation in the CRESST consortium. The NASA Goddard Space Flight Center (NASA/GSFC), The University of Maryland College Park (UMCP), Catholic University, Howard University and Southeastern Universities Research Association (SURA) are our partners in the consortium.

The Center for Research and Exploration in Space Science & Technology (CRESST), is a cooperative agreement between the partner institutions. The CRESST consortium currently has over 120 PhD astronomers and astrophysicists working within the Astrophysics Science Division at GSFC.

CSST was formed in 2006 and currently has over 20 UMBC research faculty, several of which are affiliated to the physics department. The research conducted by the members of CSST focuses on (i) Astrophysical Data Reduction, Interpretation & Archiving, (ii) Space Science Technology: Development & Calibration, and (iii) Theoretical Astrophysics: Simulations & Software.

CSST maintains close relations with (and is housed within) the Physics Department at UMBC. Combined, UMBC astrophysics faculty and CSST scientists contribute to the Undergraduate & Graduate activities (including the Undergrad & Grad internships) by teaching & mentoring students.

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Infrared Band Strengths and Other Properties of Three Interstellar Compounds—Amorphous Isocyanic Acid, Formaldehyde, and Formic Acid
(IOP Science, 2024-12-09) Hudson, Reggie L.; Yarnall, Yukiko; Gerakines, Perry A.
Infrared (IR) spectral features of interstellar and solar system ices have been attributed to solid organic and inorganic compounds for over 50 yr, but in many cases the laboratory IR data needed to fully quantify such work have never been published, forcing researchers to rely on assumptions about gas- or liquid-phase measurements to interpret data for ices. Here, we report the first mid-IR intensity measurements for isocyanic acid (HNCO) ices that are free of such assumptions, providing new results for use by both observational and laboratory astrochemists. We also report similar new IR data for both formaldehyde (H₂CO) and formic acid (HCOOH), which have been discussed in the astrochemical literature for decades, but again without adequate laboratory data to help quantify observational results. Densities and refractive indices of HNCO, H₂CO, and HCOOH as amorphous ices also are reported. Two applications of the new H₂CO work are presented, the first vapor-pressure measurements of solid H₂CO, along with an enthalpy of sublimation, at 100 to 109 K and a set of IR intensities of H₂CO in H₂O + H₂CO ices. Band strengths, absorption coefficients, and optical constants are calculated for all three compounds. Extensive comparisons are made to older results, which are not recommended for future use.
Influence of Bulk Compressibility on Tides in Rocky and Icy Worlds
(2024-12-12) Renaud, Joe P.; Wagner, Nick; Cascioli, Gael; Goossens, Sander J.; Henning, Wade
The tidal response of terrestrial planets or icy moons is a complex interplay between the interior and orbit of the world. A significant factor in this response comes from the thermal and viscoelastic state of the deep interior. Suggesting that if measurements of the tidal and mass-loading (if applicable) response are obtained with sufficient precision, then tides can provide a probe of these properties that are otherwise hidden from other measurement techniques. This has been utilized across the Solar System to constrain questions such as, does Mercury or Venus have a solid core? Does our Moon have significant partial melting in its mantle? Or do icy moons in the outer Solar System contain large, and astrobiologically relevant, liquid oceans? New missions like BepiColombo, VERITAS, Europa Clipper, and more will provide high-precision measurements of tidally-relevant properties such as the Love Number k₂ (and perhaps h₂ and their phase lags). However, linking these observations to the interior requires proper modeling of all the major factors that drive changes in these values.In this study, we look at an often-omitted concept in tidal modeling: Bulk Compressibility, which is the inclusion of bulk modulus in the viscoelastic-gravitational equations used to calculate planetary Love numbers. Including bulk modulus can be mathematically and computationally complex so it is not uncommon to ignore it. This is occasionally justified by the misnomer of “compressibility” being only relevant to large bodies. However, bulk compressibility is not directly dependent on the size or mass of a planet. Instead, it provides another degree of freedom for the world to respond to tidal or loading stresses.In this presentation, we will discuss the background and theory behind bulk compressibility and showcase that its addition can have a measurable impact on tidal and loading Love numbers. For example, work by this team has shown that it can lead to >20% difference in the tidal and loading Love number k₂ and up to 40% difference for h₂. Furthermore, it can significantly alter the phase lag of these numbers which is an important probe of thermal and rheological properties. Finally, we will discuss when bulk compressibility can be ignored and what sort of measurement precision is most affected.
IN ISLANDIA, VERITAS: CHARACTERIZATION OF VENUS SURFACE ANALOGS
(USRA, 2024) Nunes, D. C.; Smrekar, S. E.; Hensley, S; Adeli, S.; Alemanno, G.; Cascioli, Gael; Zebker, H.
A RADIO SCIENCE EXPERIMENT TO STUDY THE INTERIOR OF THE URANIAN MOONS.
(Space Pole, 2024) Filice, Valerio; Cascioli, Gael; Le Maistre, Sebastien; Baland, Rose-Marie; Mazarico, Erwan; Goossens, Sander J.
The five largest moons of Uranus, as well as Uranus itself, have mostly been studied through ground-based observations [e.g., 1]. Only Voyager 2 provided in situ measurements that significantly enhanced our understanding of the system [2,3]. As a ten-year launch window approaches, the scientific community has agreed on the importance of prioritizing a robotic mission to Uranus, proposing it as the next NASA flagship-class mission [4]. In response to this, NASA is reviewing the Uranus Orbiter and Probe (UOP) mission concept [5]. The concept was evaluated by the most recent Planetary Science and Astrobiology Decadal Survey [4] as a low-risk, relatively low-cost, and high-reward mission. Upon arrival, the mission would deploy an atmospheric probe, settle into orbit around Uranus for 4.5 Earth years, and conduct flybys of several moons. A Radio Science (RS) experiment that includes multiple satellite flybys (in addition to the orbital phase around Uranus) can provide valuable information about the interior properties, formation, evolution, and potential habitability of the planetary bodies in the Uranian system, as previously demonstrated [6-7]. An RS experiment can answer key science questions regarding the internal structure and rock-to-ice ratios of the large satellites of Uranus, and help identifying significant internal heat sources or possible oceans.
Gravity Science With the Uranus Orbiter
(2024-07-25) Mazarico, Erwan; Cascioli, Gael; Goossens, Sander; Filice, Valerio; Maistre, Sebastien Le
The Cassini and Juno missions have considerably expanded our understanding of Saturn, Jupiter, and their moons. The spacecraft radio tracking data acquired by the NASA Deep Space Network (DSN) have enabled the accurate measurement of gravitational perturbations of these planetary bodies on the spacecraft trajectory. The inferred static zonal gravity fields have been key in understanding the interior structure and dynamics within Jupiter and Saturn. Repeated flybys of moons such as Titan and Enceladus can also constrain their interior properties, putting constraints on their formation and evolution, and potential habitability. The exploration of the Uranus system by NASA’s future flagship mission (Uranus Orbiter and Probe, UOP) holds the promise of making similar gains for Uranus and its moons. Here we address the gravity science that may be possible with UOP.
FIRST LASER RANGING RESULTS FROM THE LUNAR RECONNAISSANCE ORBITER TO THE MINIATURE LASER RETROREFLECTOR ARRAY ON CHANDRAYAAN-3
(USRA, 2024) Sun, X.; Cremons, D. R.; Smith, D. E.; Neumann, G. A.; Mao, D.; Barker, M.K.; Mazarico, E.; Cascioli, Gael; Bertone, S.; Tomio, H.; Head, J. W. III; Robinson, M. S.; Aharonson, O.; Zuber,, M. T.; Petro, N. E.; Veeramuthuvel, P.; Kumar, G. Senthil; Megala, S.
A laser range measurement from the Lunar Reconnaissance Orbiter (LRO) to the Chandrayaan-3 lunar lander has been accomplished. The Lunar Orbiter Laser Altimeter (LOLA) on LRO has successfully detected the signal reflected by the miniaturelaser retroreflector array (LRA) on Chandrayaan-3 of the Indian Space Research Organisation (ISRO).
EXPLORING THE VENUS CRUST AND LITHOSPHERE WITH THE VERITAS GRAVITY SCIENCE
(USRA, 2023) Mazarico, Erwan; Iess, Luciano; Cascioli, Gael; Durante, Daniele; Marchi, Fabrizio De; Smrekar, Suzanne
The Venus Emissivity, Radio Science, InSAR, Topography And Spectroscopy (VERITAS) mission [1] was selected under NASA’s Discovery program in June 2021. Along with DAVINCI and EnVision, the decade of Venus is now on the horizon. VERITAS will answer key questions related to the geologic and volcanic history of Venus and inform on the current structure of the interior, from crust to core [2]. This will address important gaps in our understanding of the diverging evolutionary paths taken by Earth and Venus over the courses of the past few billions of years. The interferometric radar VISAR [3] will map the planet morphology and topography at high resolution, well surpassing the Magellan datasets and bringing our knowledge of Venus in line with other terrestrial bodies (Moon, Mars, Mercury). The gravity science investigation will constrain the subsurface structure by measuring the gravity field to high resolution, as well as the deep interior through its lowdegree gravity and orientation dynamics. Here, we focus on the former, and particularly the cr
DETECTABILITY OF TECTONO-MAGMATIC STRUCTURES IN THE VENUS GRAVITY FIELD
(USRA, 2024) Gülcher, Anna; Mazarico, Erwan; Smrekar, Suzanne E; Schools, Joe W
This study models coronae gravity signals, addressing formation scenarios and distinguishing active from inactive ones. Utilizing topographic and gravity data, the research anticipates insights from the upcoming VERITAS mission.
Constraining the interior structure of crustal plateaus on Venus in the context of future space missions.
(Europlanet Science Congress, 2024-07-03) Baccarin, Jacopo; Maia, Julia; Cascioli, Gael; Plesa, Ana-Catalina; Mueller, Nils; Mazarico, Erwan; Breuer, Doris; Smrekar, Suzanne
Crustal plateaus are large, high elevation physiographic features on Venus associated with the strongly deformed tessera terrains. They present positive, low magnitude gravity anomalies, and they are stratigraphically the oldest surfaces on the planet [1]. Previous investigations of the gravity and topography signatures of the plateaus have shown that these regions are consistent with shallow support via crustal thickening [2, 3]. In addition, surface emissivity data obtained by Venus Express have shown that the plateaus are associated with low emissivity anomalies, which could be indicative of a felsic composition [4]. Given these observational data sets that are summarized in Figure 1 for Alpha Regio, crustal plateaus could be analogues to the continents on Earth, which would have major implications for our understanding of the tectonic and geodynamic processes that operated throughout Venus’ evolution. Therefore, a careful investigation of the origin and evolution of these features is one of the main objectives of the future missions to Venus.
X-ray properties of coronal emission in radio quiet Active Galactic Nuclei
(2024-12-20) Laha, Sibasish; Ricci, Claudio; Mather, John C.; Behar, Ehud; Gallo, Luigi C.; Marin, Frederic; Mbarek, Rostom; Hankla, Amelia
Active galactic nuclei (AGN) are powerful sources of panchromatic radiation. All AGN emit in X-rays, contributing around ∼5−10% of the AGN bolometric luminosity. The X-ray emitting region, popularly known as the corona, is geometrically and radiatively compact with a size typically ≲10RG (gravitational radii). The rapid and extreme variability in X-rays also suggest that the corona must be a dynamic structure. Decades of X-ray studies have shed much light on the topic, but the nature and origin of AGN corona are still not clearly understood. This is mostly due to the complexities involved in several physical processes at play in the high-gravity, high-density and high-temperature region in the vicinity of the supermassive black hole (SMBH). It is still not clear how exactly the corona is energetically and physically sustained near a SMBH. The ubiquity of coronal emission in AGN points to their fundamental role in black hole accretion processes. In this review we discuss the X-ray observational properties of corona in radio quiet AGN.
TOPOGRAPHIC DATA ACQUISITION FOR THE VERITAS 2023 ICELAND FIELD CAMPAIGN
(USRA, 2024) Mazarico, Erwan; Nunes, Daniel C.; Cascioli, Gael; Smrekar, Suzanne E.; Andrews-Hanna, Jeffrey; M黮ler, Nils; Iess, Luciano; Domac, Akin; Whitten, Jennifer L.; Buczkowski, Debra L.; Jozwiak, Lauren M.; Di Achille, Gaetano; Mastrogiuseppe, Marco; Hamilton, Christopher W.; Pedersen, Gro
The NASA Discovery mission VERITAS (Venus Emissivity, Radio Science, InSAR,Topography, and Spectroscopy) will explore Venus in the early 2030s, acquiring foundational global datasets that will reshape our understanding of planetary evolution [1]. In addition to a gravity science investigation [2] and a near-infrared spectrometer(VEM) [3], a synthetic aperture radar (VISAR) [4] will globally map the surface at X-band wavelength (~4 cm). To better interpret the radar backscatter measurements,relate them to physical properties such as surface roughness, and intercompare them with other radar datasets (Magellan S-band and EnVision VenSAR Sband), the VERITAS science team conducted a field campaign in Iceland, in collaboration with a multi-bandradar mapping airborne campaign by the German Aerospace Center (DLR) [5,6]
TOPOGRAPHIC DATA REDUCTION FOR THE VERITAS 2023 ICELAND FIELD CAMPAIGN
(USRA, 2024) Mazarico, E; Nunes, D; Smrekar, S; G黮cher, A; Whitten, J; Raguso, M C; Head, J
We report here on the amount and quality of the surface characterization dataset, discuss the data reduction strategy, and provide a first look at the final dataset that will be made publicly available to the scientific community.
THE VERITAS 2023 ICELAND ANALOG CAMPAIGN � DIELECTRIC PERMITTIVITY AND SAMPLING
(USRA, 2024) Nunes, D C; Buczkowski, D; Dyar, M D; Hensley, S; Jozwiak, L; Mastrogiuseppe, M; Smrekar, S E; Stock, J; Whitten, J L; Zebker, H; Science Team, VERITAS; Cascioli, Gael
The VERITAS Science Team conducted a Venus field-analog campaign to support interpretation of X-band and NIR data, test data processing algorithms, and comparison with S-band SAR from other missions (Magellan, EnVision).
The XRISM/Resolve View of the Fe K Region of Cyg X-3
(IOP Science, 2024-12) XRISM Collaboration; Audard, Marc; Awaki, Hisamitsu; Ballhausen, Ralf; Bamba, Aya; Behar, Ehud; Boissay-Malaquin, Rozenn; Brenneman, Laura; Brown, Gregory V.; Corrales, Lia; Costantini, Elisa; Cumbee, Renata; Trigo, Mar韆 D韆z; Done, Chris; Dotani, Tadayasu; Ebisawa, Ken; Eckart, Megan E.; Eckert, Dominique; Eguchi, Satoshi; Enoto, Teruaki; Ezoe, Yuichiro; Foster, Adam; Fujimoto, Ryuichi; Fujita, Yutaka; Fukazawa, Yasushi; Fukushima, Kotaro; Furuzawa, Akihiro; Gallo, Luigi; Garc韆, Javier A.; Gu, Liyi; Guainazzi, Matteo; Hagino, Kouichi; Hamaguchi, Kenji; Hatsukade, Isamu; Hayashi, Katsuhiro; Hayashi, Takayuki; Hell, Natalie; Hodges-Kluck, Edmund; Hornschemeier, Ann; Ichinohe, Yuto; Ishida, Manabu; Ishikawa, Kumi; Ishisaki, Yoshitaka; Kaastra, Jelle; Kallman, Timothy; Kara, Erin; Katsuda, Satoru; Kanemaru, Yoshiaki; Kelley, Richard; Kilbourne, Caroline; Kitamoto, Shunji; Kobayashi, Shogo; Kohmura, Takayoshi; Kubota, Aya; Leutenegger, Maurice; Loewenstein, Michael; Maeda, Yoshitomo; Markevitch, Maxim; Matsumoto, Hironori; Matsushita, Kyoko; McCammon, Dan; McNamara, Brian; Mernier, Fran鏾is; Miller, Eric D.; Miller, Jon M.; Mitsuishi, Ikuyuki; Mizumoto, Misaki; Mizuno, Tsunefumi; Mori, Koji; Mukai, Koji; Murakami, Hiroshi; Mushotzky, Richard; Nakajima, Hiroshi; Nakazawa, Kazuhiro; Ness, Jan-Uwe; Nobukawa, Kumiko; Nobukawa, Masayoshi; Noda, Hirofumi; Odaka, Hirokazu; Ogawa, Shoji; Ogorzalek, Anna; Okajima, Takashi; Ota, Naomi; Paltani, Stephane; Petre, Robert; Plucinsky, Paul; Porter, Frederick S.; Pottschmidt, Katja; Sato, Kosuke; Sato, Toshiki; Sawada, Makoto; Seta, Hiromi; Shidatsu, Megumi; Simionescu, Aurora; Smith, Randall; Suzuki, Hiromasa; Szymkowiak, Andrew; Takahashi, Hiromitsu; Takeo, Mai; Tamagawa, Toru; Tamura, Keisuke; Tanaka, Takaaki; Tanimoto, Atsushi; Tashiro, Makoto; Terada, Yukikatsu; Terashima, Yuichi; Tsuboi, Yohko; Tsujimoto, Masahiro; Tsunemi, Hiroshi; Tsuru, Takeshi; Uchida, Hiroyuki; Uchida, Nagomi; Uchida, Yuusuke; Uchiyama, Hideki; Ueda, Yoshihiro; Uno, Shinichiro; Vink, Jacco; Watanabe, Shin; Williams, Brian J.; Yamada, Satoshi; Yamada, Shinya; Yamaguchi, Hiroya; Yamaoka, Kazutaka; Yamasaki, Noriko; Yamauchi, Makoto; Yamauchi, Shigeo; Yaqoob, Tahir; Yoneyama, Tomokage; Yoshida, Tessei; Yukita, Mihoko; Zhuravleva, Irina; Tomaru, Ryota; Hayashi, Tasuku; Hakamata, Tomohiro; Miura, Daiki; Koljonen, Karri; McCollough, Mike
The X-ray binary system Cygnus X-3 (4U 2030+40, V1521 Cyg) is luminous but enigmatic owing to the high intervening absorption. High-resolution X-ray spectroscopy uniquely probes the dynamics of the photoionized gas in the system. In this Letter, we report on an observation of Cyg X-3 with the XRISM/Resolve spectrometer, which provides unprecedented spectral resolution and sensitivity in the 2� keV band. We detect multiple kinematic and ionization components in absorption and emission whose superposition leads to complex line profiles, including strong P Cygni profiles on resonance lines. The prominent Fe xxv He? and Fe xxvi Ly? emission complexes are clearly resolved into their characteristic fine-structure transitions. Self-consistent photoionization modeling allows us to disentangle the absorption and emission components and measure the Doppler velocity of these components as a function of binary orbital phase. We find a significantly higher velocity amplitude for the emission lines than for the absorption lines. The absorption lines generally appear blueshifted by ??500�0 km s?1. We show that the wind decomposes naturally into a relatively smooth and large-scale component, perhaps associated with the background wind itself, plus a turbulent, denser structure located close to the compact object in its orbit.
Probing the X-ray Reprocessing Geometry in High-Mass X-ray Binaries with the Chandra High Energy Transmission Grating
(University of Liège, 2024-12-16) Tzanavaris, Panayiotis; Yaqoob, Tahir
A majority of stars reside in multiple systems, and a majority of massive stars appear in binaries. An important subset goes through an X-ray binary (XRB) phase, but the geometry of their X-ray reprocessing matter that gives rise to prominent spectral features such iron fluorescent X-ray emission remains not well understood. The similarity of XRB spectral features to those of Active Galactic Nuclei (AGN) in the X-rays motivates us to apply similar physical modeling for 10 well-known Galactic High Mass X-ray Binaries (HMXBs) observed with the Chandra High Energy Transmission Grating (HETG). Using two different state-of-the art models for X-ray reprocessing, that self-consistently model together Fe Kα fluorescent emission and scattered X-ray continua, we obtain unique insights into the geometry and kinematics of the accretion flow in these systems. Here, we present constraints on the shape as well as distance of the X-ray reprocessor from the accretion disk.
Overionized plasma in the supernova remnant Sagittarius A East anchored by XRISM observations
(2024-12-01) XRISM Collaboration; Boissay-Malaquin, Rozenn; Hamaguchi, Kenji; Hayashi, Takayuki; Mukai, Koji; Pottschmidt, Katja; Tamura, Keisuke; Yaqoob, Tahir
Sagittarius A East is a supernova remnant with a unique surrounding environment, as it is located in the immediate vicinity of the supermassive black hole at the Galactic center, Sagittarius A*. The X-ray emission of the remnant is suspected to show features of overionized plasma, which would require peculiar evolutionary paths. We report on the first observation of Sagittarius A East with X-Ray Imaging and Spectroscopy Mission (XRISM). Equipped with a combination of high-resolution microcalorimeter spectrometer and large field-of-view CCD imager, we for the first time resolved the Fe XXV K-shell lines into fine structure lines and measured the forbidden-to-resonance intensity ratio to be 1.39+/-0.12, which strongly suggests the presence of overionized plasma. We obtained a reliable constraint on the ionization temperature just before the transition into the overionization state, to be > 4 keV. The recombination timescale was constrained to be < 8e11 cm-3 s. The small velocity dispersion of 109+/-6 km s-1 indicates a low Fe ion temperature < 8 keV and a small expansion velocity < 200 km s-1. The high initial ionization temperature and small recombination timescale suggest that either rapid cooling of the plasma via adiabatic expansion from dense circumstellar material or intense photoionization by Sagittarius A* in the past may have triggered the overionization.
Near-Infrared Data Acquisition for the VERITAS 2023 Iceland Field Campaign
(Europlanet Science Congress, 2024-07-03) Adeli, Solmaz; Garland, Stephen; Nunes, Daniel; Smrekar, Sue; Mueller, Nils; Domac, Akin; Alemanno, Giulia; Hamilton, Christopher; Pedersen, Gro; Cascioli, Gael; Althaus, Christian; Hauber, Ernst; Trauthan, Frank; Barraud, Oceane; Wendler, Dennis; Demirok, Rana; Chauhan, Shreya; Helbert, Joern; The VERITAS Science Team
In this campaign, we collected in-situ NIR data and 60 kg of samples of Venus analog materials. We are currently at the post-processing phase of the data and sample analyses. Correlation with the surface roughness and permittivity is also planned for the near future. By comparing the field and laboratory datasets, we can assess the capabilities of the VEM instrument in distinguishing lava types and compositions. Correlation with other field datasets will help finding close synergies with other instruments in preparation for the Venus missions. This work lays a foundation for detailed interpretation of Venus mineralogy and is vital preparation for the scientific goals of the NASA VERITAS and ESA EnVision.
Monodromy eigenvalues of the radial Teukolsky equation and their connection to the renormalized angular momentum
(2024-12-09) Nasipak, Zachary
The Teukolsky equation describes perturbations of Kerr spacetime and is central to the study of rotating black holes and gravitational waves. In the frequency domain, the Teukolsky equation separates into radial and angular ordinary differential equations. Mano, Suzuki, and Takasugi (MST) found semi-analytic solutions to the homogeneous radial Teukolsky equation in terms of series of analytic special functions. The MST expansions hinge on an auxiliary parameter known as the renormalized angular momentum $\nu$, which one must calculate to ensure the convergence of these series solutions. In this work, we present a method for calculating $\nu$ via monodromy eigenvalues, which capture the behavior of ordinary differential equations and their solutions in the complex domain near their singular points. We directly relate the monodromy data of the radial Teukolsky equation to the parameter $\nu$ and provide a numerical scheme for calculating $\nu$ based on monodromy. With this method we evaluate $\nu$ in different regions of parameter space and analyze the numerical stability of this approach. We also highlight how, through $\nu$, monodromy data are linked to scattering amplitudes for generic (linear) perturbations of Kerr spacetime.
Periodic Gamma-Ray Modulation of the Blazar PG 1553+113 Confirmed by Fermi-LAT and Multiwavelength Observations
(IOP, 2024-11-25) Abdollahi, S.; Baldini, L.; Barbiellini, G.; Bellazzini, R.; Berenji, B.; Bissaldi, E.; Blandford, R. D.; Bonino, R.; Bruel, P.; Buson, S.; Cameron, R. A.; Caraveo, P. A.; Casaburo, F.; Cavazzuti, E.; Cheung, C. C.; Chiaro, G.; Ciprini, S.; Cozzolongo, G.; Orestano, P. Cristarella; Cutini, S.; D’Ammando, F.; Lalla, N. Di; Dirirsa, F.; Venere, L. Di; Domínguez, A.; Fegan, S. J.; Ferrara, E. C.; Fiori, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Garrappa, S.; Gasparrini, D.; Germani, S.; Giglietto, N.; Giordano, F.; Giroletti, M.; Green, D.; Grenier, I. A.; Guiriec, S.; Hays, E.; Horan, D.; Kuss, M.; Larsson, S.; Laurenti, M.; Li, J.; Liodakis, I.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Maldera, S.; Malyshev, D.; Manfreda, A.; Marcotulli, L.; Martí-Devesa, G.; Mazziotta, M. N.; Mereu, I.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Negro, M.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Perri, M.; Persic, M.; Pesce-Rollins, M.; Porter, T. A.; Principe, G.; Rainò, S.; Rando, R.; Rani, Bindu; Razzano, M.; Reimer, A.; Reimer, O.; Parkinson, P. M. Saz; Scotton, L.; Serini, D.; Sesana, A.; Sgrò, C.; Siskind, E. J.; Spandre, G.; Spinelli, P.; Suson, D. J.; Tajima, H.; Takahashi, M. N.; Tak, D.; Thayer, J. B.; Thompson, D. J.; Torres, D. F.; Valverde, Janeth; Verrecchia, F.; Zaharijas, G.
A 2.1 yr periodic oscillation of the gamma-ray flux from the blazar PG 1553+113 has previously been tentatively identified in ?7 yr of data from the Fermi Large Area Telescope. After 15 yr of Fermi sky-survey observations, doubling the total time range, we report >7 cycle gamma-ray modulation with an estimated significance of 4? against stochastic red noise. Independent determinations of oscillation period and phase in the earlier and the new data are in close agreement (chance probability <0.01). Pulse timing over the full light curve is also consistent with a coherent periodicity. Multiwavelength new data from Swift X-Ray Telescope, Burst Alert Telescope, and UVOT, and from KAIT, Catalina Sky Survey, All-Sky Automated Survey for Supernovae, and Owens Valley Radio Observatory ground-based observatories as well as archival Rossi X-Ray Timing Explorer satellite-All Sky Monitor data, published optical data of Tuorla, and optical historical Harvard plates data are included in our work. Optical and radio light curves show clear correlations with the gamma-ray modulation, possibly with a nonconstant time lag for the radio flux. We interpret the gamma-ray periodicity as possibly arising from a pulsational accretion flow in a sub-parsec binary supermassive black hole system of elevated mass ratio, with orbital modulation of the supplied material and energy in the jet. Other astrophysical scenarios introduced include instabilities, disk and jet precession, rotation or nutation, and perturbations by massive stars or intermediate-mass black holes in polar orbit.
Visualization for Cyber Complex Systems: Application, Issues and Future Work
(2024) Nikolov, Georgi; Varga, Margaret; Träber-Burdin, Susan; Winkelholz, Carsten; Kullman, Kaur; Lavigne, Valérie
Technology advances at a rapid pace; new components are being developed, offering opportunities to create even more intricate networks of devices, interconnected on both local and global scale, offering ever faster processing while generating vast amounts of data. Technological advancements facilitate improvements for individuals’ daily lives, our work environment, societal enhancements, military defense capabilities, etc. Unfortunately, when an issue manifests in these new networks, it is often difficult to immediately identify the origin and apply an appropriate solution in a timely fashion. The infrastructure built to sustain our society’s needs has become complicated and interconnected, evolving into a complex system rather than a complicated one. Complex systems are difficult to manage without an in-depth knowledge of the underlying components and their interactions - where the whole is greater than the sum of its parts. To aid in this task, new ways to visualize such a system of systems need to be developed to represent them accordingly and enable its operators to identify problems and apply actionable solutions. In this paper, we offer a detailed explanation on what complex systems are, the difficulty of maintaining actionable situational awareness and understanding, and how Visual Analytics and Data Visualization can help in resolving some of these issues. Examples of visual representations will be discussed, together with techniques used for their evaluations in terms of their usefulness and usability. Finally, a brief overview of possible future advancements that can support better understanding and management of complex systems will be discussed.

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