Astrophysics and Astronomy Commons^™

Constraints On Cosmic Strings Using Data From The Third Advanced Ligo–Virgo Observing Run, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Karla E. Ramirez, W. H. Wang

Physics & Astronomy Faculty Publications

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop …

Comparing The Inner And Outer Star-Forming Complexes In The Nearby Spiral Galaxies Ngc 628, Ngc 5457, And Ngc 6946 Using Uvit Observations, Stacy S. Mcgaugh

Faculty Scholarship

We present a far-UV (FUV) study of the star-forming complexes (SFCs) in three nearby galaxies using the Ultraviolet Imaging Telescope. The galaxies are close to face-on and show significant outer disk star formation. Two of them are isolated (NGC 628 and NGC 6946), and one is interacting with distant companions (NGC 5457). We compared the properties of the SFCs inside and outside the optical radius (R 25). We estimated the sizes, star formation rates (SFRs), metallicities, and Toomre Q parameter of the SFCs. We find that the outer disk SFCs are at least 10 times smaller in area than those …

Attractive And Repulsive Residue Fragments At The Interface Of Sars-Cov-2 And Hace2, Jorge H. Rodriguez

Purdue University Libraries Open Access Publishing Fund

The initial stages of SARS-CoV-2 coronavirus attachment to human cells are mediated by non-covalent interactions of viral spike (S) protein receptor binding domains (S-RBD) with human ACE2 receptors (hACE2). Structural characterization techniques, such as X-ray crystallography (XRC) and cryoelectron microscopy (cryo-EM), previously identified SARS-CoV-2 spike protein conformations and their surface residues in contact with hACE2. However, recent quantum-biochemical calculations on the structurally related S-RBD of SARS-CoV-1 identified some contact-residue fragments as intrinsically attractive and others as repulsive. This indicates that not all surface residues are equally important for hACE2 attachment. Here, using similar quantum-biochemical methods, we report some four-residue fragments …

Tests Of General Relativity With Binary Black Holes From The Second Ligo-Virgo Gravitational-Wave Transient Catalog, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, A. Adams, C. Adams, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, S. Akcay, G. Allen, Tiffany Z. Summerscales

Faculty Publications

Gravitational waves enable tests of general relativity in the highly dynamical and strong-field regime. Using events detected by LIGO-Virgo up to 1 October 2019, we evaluate the consistency of the data with predictions from the theory. We first establish that residuals from the best-fit waveform are consistent with detector noise, and that the low- and high-frequency parts of the signals are in agreement. We then consider parametrized modifications to the waveform by varying post-Newtonian and phenomenological coefficients, improving past constraints by factors of ∼2; we also find consistency with Kerr black holes when we specifically target signatures of the spin-induced …

Tests Of General Relativity With Binary Black Holes From The Second Ligo-Virgo Gravitational-Wave Transient Catalog, Ligo Scientific Collaboration, Virgo Collaboration, Tiffany Z. Summerscales

Faculty Publications

Gravitational waves enable tests of general relativity in the highly dynamical and strong-field regime. Using events detected by LIGO-Virgo up to 1 October 2019, we evaluate the consistency of the data with predictions from the theory. We first establish that residuals from the best-fit waveform are consistent with detector noise, and that the low- and high-frequency parts of the signals are in agreement. We then consider parametrized modifications to the waveform by varying post-Newtonian and phenomenological coefficients, improving past constraints by factors of ∼2; we also find consistency with Kerr black holes when we specifically target signatures of the spin-induced …

Tests Of General Relativity With Binary Black Holes From The Second Ligo-Virgo Gravitational-Wave Transient Catalog, R. Abbott, S. Abraham, F. Acernese, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Karla E. Ramirez, Wenhui Wang

Physics & Astronomy Faculty Publications

Gravitational waves enable tests of general relativity in the highly dynamical and strong-field regime. Using events detected by LIGO-Virgo up to 1 October 2019, we evaluate the consistency of the data with predictions from the theory. We first establish that residuals from the best-fit waveform are consistent with detector noise, and that the low- and high-frequency parts of the signals are in agreement. We then consider parametrized modifications to the waveform by varying post-Newtonian and phenomenological coefficients, improving past constraints by factors of ∼2; we also find consistency with Kerr black holes when we specifically target signatures of the spin-induced …

Loop Quantum Black Hole Extensions Within The Improved Dynamics, Rodolfo Gambini, Javier Olmedo, Jorge Pullin

Faculty Publications

We continue our investigation of an improved quantization scheme for spherically symmetric loop quantum gravity. We find that in the region where the black hole singularity appears in the classical theory, the quantum theory contains semi-classical states that approximate general relativity coupled to an effective anisotropic fluid. The singularity is eliminated and the space-time can be continued into a white hole space-time. This is similar to previously considered scenarios based on a loop quantum gravity quantization.

Double Polarisation Observable G For Single Pion Photoproduction From The Proton, N. Zachariou, D. P. Watts, J. Mcandrew, L. Zana, M. Bashkanov, I. I. Strakovsky, R. Workman, A. V. Sarantsev, V. Nikonov, K. P. Adhikari, S. Adhikari, M. J. Amaryan, G. Angelini, W. R. Armstrong, H. Atac, N. A. Baltzell, L. Barion, M. Battaglieri, I. Bedlinskiy, F. Benmokhtar, Steffen Strauch, Et. Al.

Faculty Publications

We report measurements of π⁺ and π⁰ meson photoproduction from longitudinally spin-polarised protons by an energy tagged (0.73-2.3 GeV) and linearly polarised photon beam. A close to complete solid angle coverage for the reaction products was provided by the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The double-polarisation observable G is extracted from Maximum Likelihood fits to the data, enabling the first accurate determination for the reaction γ p → π⁺n, while also significantly extending the kinematic coverage for γ p → π⁰ p. This large data set provides an important constraint on the properties …

Quark Matter Contribution To The Heat Capacity Of Magnetized Neutron Stars, Efrain J. Ferrer, Vivian De La Incera, P. Sanson

Physics & Astronomy Faculty Publications

In this paper, we find the heat capacity of the magnetic dual chiral density wave (MDCDW) phase of dense quark matter and use it to explore the feasibility of this phase for a neutron star interior. MDCDW is a spatially inhomogeneous phase of quark matter known to be favored at intermediate densities over the chirally symmetric phase and the color-flavor-locked superconducting phase. By comparing our result to the lower limit of the core heat capacity established from observations of transiently accreting neutron stars, we show that the heat capacity of MDCDW quark matter is well above that lower limit and …

The Effects Of Water Ice Sublimation On Slope Failures Of Icy Regolith, Christopher Cox, Madison Weinberg, Trisha Joseph

The Pegasus Review: UCF Undergraduate Research Journal

The frost line in a planetary system represents the distance from the central star inside of which conditions are too warm for ice to form, while beyond this line it will be stable. When an icy object passes that line heading toward the Sun it will begin to sublimate and outgas, potentially causing mass loss and surface changes. One example is surface failures, which can lead to material being removed from the object. Evidence of this has been seen on cometary surfaces, where surfaces often show structures that appear to have suffered various mechanical failures like cracking and landslides. By …

Gwtc-2: Compact Binary Coalescences Observed By Ligo And Virgo During The First Half Of The Third Observing Run, R. Abbott, T. D. Abbott, S. Abraham, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Karla E. Ramirez, W. H. Wang

Physics & Astronomy Faculty Publications

We report on gravitational-wave discoveries from compact binary coalescences detected by Advanced LIGO and Advanced Virgo in the first half of the third observing run (O3a) between 1 April 2019 15∶00 UTC and 1 October 2019 15∶00 UTC. By imposing a false-alarm-rate threshold of two per year in each of the four search pipelines that constitute our search, we present 39 candidate gravitational-wave events. At this threshold, we expect a contamination fraction of less than 10%. Of these, 26 candidate events were reported previously in near-real time through gamma-ray coordinates network notices and circulars; 13 are reported here for the …

The Hubble Pancet Program: Long-Term Chromospheric Evolution And Flaring Activity Of The M Dwarf Host Gj 3470★, Vincent Bourrier, Leonardo A. Dos Santos, Jorge Sanz-Forcada, Antonio García Muñoz, Gregory W. Henry, Panayotis Lavvas, Alain Lecavelier, Mercedes López-Morales, Thomas Mikal-Evans, David K. Sing, Hannah R. Wakeford, David Ehrenreich

Information Systems and Engineering Management Research Publications

Neptune-size exoplanets seem particularly sensitive to atmospheric evaporation, making it essential to characterize the stellar high-energy radiation that drives this mechanism. This is particularly important with M dwarfs, which emit a large and variable fraction of their luminosity in the ultraviolet and can display strong flaring behavior. The warm Neptune GJ 3470b, hosted by an M2 dwarf, was found to harbor a giant exosphere of neutral hydrogen thanks to three transits observed with the Hubble Space Telescope Imaging Spectrograph (HST/STIS). Here we report on three additional transit observations from the Panchromatic Comparative Exoplanet Treasury program, obtained with the HST Cosmic …

An Ultra-Short-Period Transiting Super-Earth Orbiting The M3 Dwarf Toi-1685, P. Bluhm, E. Pallé, K. Molaverdikhani, J. Kemmer, A. P. Hatzes, D. Kossakowski, S. Stock, J. A. Caballero, J. Lillo-Box, V. J. S. Béjar, M. G. Soto, P. J. Amado, P. Brown, C. Cadieux, R. Cloutier, K. A. Collins, K. I. Collins, M. Cortés-Contreras, R. Doyon, S. Dreizler, N. Espinoza, A. Fukui, E. González-Álvarez, T. Henning, K. Horne, S. V. Jeffers, J. M. Jenkins, Eric L.N. Jensen, A. Kaminski, J. F. Kielkopf, N. Kusakabe, M. Kürster, D. Lafrenière, R. Luque, F. Murgas, D. Montes, J. C. Morales, N. Narita, V. M. Passegger, A. Quirrenbach, P. Schöfer, S. Reffert, A. Reiners, I. Ribas, G. R. Ricker, S. Seager, A. Schweitzer, R. P. Schwarz, M. Tamura, T. Trifonov, R. Vanderspek, J. Winn, M. Zechmeister, M. R. Zapatero Osorio

Physics & Astronomy Faculty Works

Dynamical histories of planetary systems, as well as the atmospheric evolution of highly irradiated planets, can be studied by characterizing the ultra-short-period planet population, which the TESS mission is particularly well suited to discover. Here, we report on the follow-up of a transit signal detected in the TESS sector 19 photometric time series of the M3.0 V star TOI-1685 (2MASS J04342248+4302148). We confirm the planetary nature of the transit signal, which has a period of Pb = 0.6691403−0.0000021+0.0000023 d, using precise radial velocity measurements taken with the CARMENES spectrograph. From the joint photometry and radial velocity analysis, we estimate the …

Analysis Of The Primary Volatile Compositions In The Oort Cloud And Jupiter-Family Comets Towards The Goal Of Understanding Their Origin And Diversity, Mohammad Saki

Dissertations

Knowledge of the initial conditions present in the early solar nebula is required to understand the evolution and its current volatile content. Comets were some of the first objects to accrete in the solar nebula. They are among the most pristine (primitive) remnants of the solar system formation, and their present-day volatile composition likely reflects the composition and conditions where (and when) they formed. Therefore, they are fossils of the solar system formation. High-resolution near-infrared spectroscopy is a valuable tool for sampling the parent volatile (i.e., ices subliming directly from the nucleus) composition of comets via analysis of fluorescence emission …

Observations With The Differential Speckle Survey Instrument. X. Preliminary Orbits Of K-Dwarf Binaries And Other Stars, Elliott P. Horch, Kyle G. Broderick, Dana I. Casetti-Dinescu, Todd J. Henry, Francis C. Fekel, Matthew W. Muterspaugh, Daryl W. Willmarth, Jennifer G. Winters, Gerard T. Van Belle, Catherine A. Clark, Mark E. Everett

Information Systems and Engineering Management Research Publications

This paper details speckle observations of binary stars taken at the Lowell Discovery Telescope, the WIYN telescope, and the Gemini telescopes between 2016 January and 2019 September. The observations taken at Gemini and Lowell were done with the Differential Speckle Survey Instrument (DSSI), and those done at WIYN were taken with the successor instrument to DSSI at that site, the NN-EXPLORE Exoplanet Star and Speckle Imager (NESSI). In total, we present 378 observations of 178 systems, and we show that the uncertainty in the measurement precision for the combined data set is ∼2 mas in separation, ∼1°–2° in position angle …

Sphincs_Bssn: A General Relativistic Smooth Particle Hydrodynamics Code For Dynamical Spacetimes, S. Rosswog, P. Diener

Faculty Publications

We present a new methodology for simulating self-gravitating general-relativistic fluids. In our approach the fluid is modelled by means of Lagrangian particles in the framework of a general-relativistic (GR) smoothed particle hydrodynamics (SPH) formulation, while the spacetime is evolved on a mesh according to the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) formulation that is also frequently used in Eulerian GR-hydrodynamics. To the best of our knowledge this is the first Lagrangian fully general relativistic hydrodynamics code (all previous SPH approaches used approximations to GR-gravity). A core ingredient of our particle-mesh approach is the coupling between the gas (represented by particles) and the spacetime (represented …

Dna-Topology Simplification By Topoisomerases, Andreas Hanke, Riccardo Ziraldo, Stephen D. Levene

Physics & Astronomy Faculty Publications

The topological properties of DNA molecules, supercoiling, knotting, and catenation, are intimately connected with essential biological processes, such as gene expression, replication, recombination, and chromosome segregation. Non-trivial DNA topologies present challenges to the molecular machines that process and maintain genomic information, for example, by creating unwanted DNA entanglements. At the same time, topological distortion can facilitate DNA-sequence recognition through localized duplex unwinding and longer-range loop-mediated interactions between the DNA sequences. Topoisomerases are a special class of essential enzymes that homeostatically manage DNA topology through the passage of DNA strands. The activities of these enzymes are generally investigated using circular DNA …

Measurement Of The Branching Fraction Of The Decay B+ →Π+Π-ℓ+Νℓ In Fully Reconstructed Events At Belle, C. Beleño, A. Frey, I. Adachi, H. Aihara, D. M. Asner, H. Atmacan, T. Aushev, R. Ayad, P. Behera, J. Bennett, F. Bernlochner, V. Bhardwaj, T. Bilka, J. Biswal, G. Bonvicini, A. Bozek, M. Bračko, T. E. Browder, M. Campajola

Faculty and Student Publications

We present an analysis of the exclusive B+→π+π-ℓ+νℓ decay, where ℓ represents an electron or a muon, with the assumption of charge-conjugation symmetry and lepton universality. The study exploits the full ϒ(4S) data sample collected by the Belle detector, corresponding to 711 fb-1 of integrated luminosity. Events are selected by fully reconstructing one B meson in hadronic decay modes, subsequently determining the properties of the other B meson. We extract the signal yields using a binned maximum-likelihood fit to the missing-mass squared distribution in bins of the invariant mass of the two pions or the momentum transfer squared. We measure …

Measurements Of Branching Fractions And Asymmetry Parameters Of Ξc0→ΛK¯∗0 , Ξc0→Σ0K¯∗0 , And Ξc0→Σ+K∗− Decays, S. Jia, S. S. Tang, C. P. Shen, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, S. Bahinipati, P. Behera, J. Bennett, M. Bessner, T. Bilka, J. Biswal, A. Bobrov, G. Bonvicini

Faculty and Student Publications

Using a data sample of 980 fb−1 collected with the Belle detector at the KEKB asymmetric-energy e+e− collider, we study the processes of Ξc0→ΛK¯∗0, Ξc0→Σ0K¯∗0, and Ξc0→Σ+K∗− for the first time. The relative branching ratios to the normalization mode of Ξc0→Ξ−π+ are measured to beB(Ξc0→ΛK¯∗0)/B(Ξc0→Ξ−π+)=0.18±0.02(stat.)±0.01(syst.),B(Ξc0→Σ0K¯∗0)/B(Ξc0→Ξ−π+)=0.69±0.03(stat.)±0.03(syst.),B(Ξc0→Σ+K∗−)/B(Ξc0→Ξ−π+)=0.34±0.06(stat.)±0.02(syst.), where the uncertainties are statistical and systematic, respectively. We obtainB(Ξc0→ΛK¯∗0)=(3.3±0.3(stat.)±0.2(syst.)±1.0(ref.))×10−3,B(Ξc0→Σ0K¯∗0)=(12.4±0.5(stat.)±0.5(syst.)±3.6(ref.))×10−3,B(Ξc0→Σ+K∗0)=(6.1±1.0(stat.)±0.4(syst.)±1.8(ref.))×10−3, where the uncertainties are statistical, systematic, and from B(Ξc0→Ξ−π+), respectively. The asymmetry parameters α(Ξc0→ΛK¯∗0) and α(Ξc0→Σ+K∗−) are 0.15 ± 0.22(stat.) ± 0.04(syst.) and −0.52 ± 0.30(stat.) ± 0.02(syst.), respectively, where the uncertainties are statistical followed by systematic. [Figure not available: see fulltext.]

Measurement Of The Energy Dependence Of The E + E − → Bb¯ , Bb¯ ∗ And B∗B¯ ∗ Exclusive Cross Sections, R. Mizuk, A. Bondar, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, S. Bahinipati, P. Behera, K. Belous, J. Bennett, M. Bessner, T. Bilka, J. Biswal, A. Bobrov

Faculty and Student Publications

We report the first measurement of the exclusive cross sections e+e− → BB¯ , e+e− → BB¯ ∗, and e+e− → B∗B¯ ∗ in the energy range from 10.63 GeV to 11.02 GeV. The B mesons are fully reconstructed in a large number of hadronic final states and the three channels are identified using a beam-constrained-mass variable. The shapes of the exclusive cross sections show oscillatory behavior with several maxima and minima. The results are obtained using data collected by the Belle experiment at the KEKB asymmetric-energy e+e− collider. [Figure not available: see fulltext.]

First Determination Of The Spin And Parity Of The Charmed-Strange Baryon Ξc (2970)+, T. J. Moon, K. Tanida, Y. Kato, S. K. Kim, I. Adachi, J. K. Ahn, H. Aihara, S. Al Said, D. M. Asner, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, S. Bahinipati, P. Behera, C. Beleño, J. Bennett, M. Bessner, B. Bhuyan

Faculty and Student Publications

We report results from a study of the spin and parity of Ξc(2970)+ using a 980 fb-1 data sample collected by the Belle detector at the KEKB asymmetric-energy e+e- collider. The decay angle distributions in the chain Ξc(2970)+→Ξc(2645)0π+→Ξc+π-π+ are analyzed to determine the spin of this charmed-strange baryon. The angular distributions strongly favor the Ξc(2970)+ spin J=1/2 over 3/2 or 5/2, under an assumption that the lowest partial wave dominates in the decay. We also measure the ratio of Ξc(2970)+ decay branching fractions R=B[Ξc(2970)+→Ξc(2645)0π+]/B[Ξc(2970)+→Ξc′0π+]=1.67±0.29(stat)-0.09+0.15(syst)±0.25(IS), where the last uncertainty is due to possible isospin-symmetry-breaking effects. This R value favors the spin-parity …

Measurement Of The Resonant And Nonresonant Branching Ratios In Ξc0 → Ξ0k+K-, J. T. Mcneil, J. Yelton, J. Bennett, I. Adachi, K. Adamczyk, J. K. Ahn, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, S. Bahinipati, P. Behera, M. Bessner, T. Bilka, J. Biswal

Faculty and Student Publications

Using the entire data sample of 980 fb-1 integrated luminosity collected with the Belle detector at the KEKB asymmetric-energy e+e- collider, we present an amplitude analysis measuring the branching fractions of the Cabibbo-allowed, W-exchange resonant decay Ξc0→Ξ0φ(→K+K-) with a polarized φ and the nonresonant decay via a direct process Ξc0→Ξ0K+K-. We present these measurements, relative to the normalization mode Ξ-π+, and find branching ratios B(Ξc0→Ξ0φ(→K+K-))(BΞc0→Ξ-π+)=0.036±0.004(stat.)±0.002(syst.) and B(Ξc0→Ξ0K+K-)B(Ξc0→Ξ-π+)=0.039±0.004(stat.)±0.002(syst.), which suggest that only minor cusping peaks occur in the combinatorial background of ω∗-→Ξ0K- due to these Ξc0 decays.

Measurement Of Branching Fractions And Cp Asymmetries For Ds+ →K+ (Η,Π0) And Ds+ →Π+ (Η,Π0) Decays At Belle, Y. Guan, A. J. Schwartz, K. Kinoshita, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, P. Behera, J. Bennett, M. Bessner, V. Bhardwaj, B. Bhuyan, T. Bilka, J. Biswal

Faculty and Student Publications

We report measurements of the branching fractions and CP asymmetries for Ds+→K+η, Ds+→K+π0, and Ds+→π+η decays, and the branching fraction for Ds+→π+π0. Our results are based on a data sample corresponding to an integrated luminosity of 921 fb-1 collected by the Belle detector at the KEKB e+e- asymmetric-energy collider. Our measurements of CP asymmetries in these decays are the most precise to date; no evidence for CP violation is found.

Diving Below The Spin-Down Limit: Constraints On Gravitational Waves From The Energetic Young Pulsar Psr J0537-6910, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Karla E. Ramirez, W. H. Wang

Physics & Astronomy Faculty Publications

We present a search for quasi-monochromatic gravitational-wave signals from the young, energetic X-ray pulsar PSR J0537-6910 using data from the second and third observing runs of LIGO and Virgo. The search is enabled by a contemporaneous timing ephemeris obtained using Neutron star Interior Composition Explorer (NICER) data. The NICER ephemeris has also been extended through 2020 October and includes three new glitches. PSR J0537-6910 has the largest spin-down luminosity of any pulsar and exhibits fRequent and strong glitches. Analyses of its long-term and interglitch braking indices provide intriguing evidence that its spin-down energy budget may include gravitational-wave emission from a …

Environmental Noise In Advanced Ligo Detectors, P. Nguyen, R. M. S. Schofield, A. Effler, C. Austin, V. B. Adya, M. Ball, S. Banagiri, K. Banowetz, C. Billman, Karla E. Ramirez

Physics & Astronomy Faculty Publications

The sensitivity of the advanced LIGO detectors to gravitational waves can be affected by environmental disturbances external to the detectors themselves. Since the transition from the former initial LIGO phase, many improvements have been made to the equipment and techniques used to investigate these environmental effects. These methods have aided in tracking down and mitigating noise sources throughout the first three observing runs of the advanced detector era, keeping the ambient contribution of environmental noise below the background noise levels of the detectors. In this paper we describe the methods used and how they have led to the mitigation of …

Gravity K-Band Spectroscopy Of Hd 206893 B, Jens Kammerer, S. Lacour, T. Stolker, P. Mollière, D. K. Sing, E. Nasedkin, Pierre Kervella, J. J. Wang, Kimberly Ward-Duong, Et Al

Astronomy: Faculty Publications

Context. Near-infrared interferometry has become a powerful tool for studying the orbital and atmospheric parameters of substellar companions.

Aims. We aim to reveal the nature of the reddest known substellar companion HD 206893 B by studying its near-infrared colors and spectral morphology and by investigating its orbital motion. Methods. We fit atmospheric models for giant planets and brown dwarfs and perform spectral retrievals with petitRADTRANS and ATMO on the observed GRAVITY, SPHERE, and GPI spectra of HD 206893 B. To recover its unusual spectral features, first and foremost its extremely red near-infrared color, we include additional extinction by high-altitude dust …

Fabrication Of Nd3+ And Yb3+ Doped Nir Emitting Nano Fluorescent Probe: A Candidate For Bioimaging Applications, D. Karthickraja, G. A. Kumar, D. K. Sardar, S. Karthi, Gamage C. Dannangoda, Karen S. Martirosyan, M. Prasath, M. Gowri, E. L. Girija

Physics & Astronomy Faculty Publications

The intentional design of rare earth doped luminescent architecture exhibits unique optical properties and it can be considered as a promising and potential probe for optical imaging applications. Calcium fluoride (CaF2) nanoparticles doped with optimum concentration of Nd3+ and Yb3+ as sensitizer and activator, respectively, were synthesized by wet precipitation method and characterized by x-ray diffraction (XRD) and photoluminescence. In spite of the fact that the energy transfer takes place from Nd3+ to Yb3+, the luminescence intensity was found to be weak due to the lattice defects generated from the doping of trivalent cations (Nd3+ and Yb3+) for divalent host …

The Observable Supernova Rate In Galaxy–Galaxy Lensing Systems With The Tess Satellite, Benne Holwerda, S Knabel, R C. Steele, L Strolger, J Kielkopf, A Jacques, W Roemer

Faculty and Staff Scholarship

The Transiting Exoplanet Survey Satellite (TESS) is the latest observational effort to find exoplanets and map bright transient optical phenomena. Supernovae (SNe) are particularly interesting as cosmological standard candles for cosmological distance measures. The limiting magnitude of TESS strongly constrains SN detection to the very nearby Universe (m ∼ 19, z < 0.05). We explore the possibility that more distant SNe that are gravitationally lensed and magnified by a foreground galaxy can be detected by TESS, an opportunity to measure the time delay between light paths and constrain the Hubble constant independently. We estimate the rate of occurrence of such systems, assuming reasonable distributions of magnification, host dust attenuation, and redshift. There are approximately 16 Type Ia SNe (SNIa) and …

Diving Below The Spin-Down Limit: Constraints On Gravitational Waves From The Energetic Young Pulsar Psr J0537-6910, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, A. Adams, C. Adams, R. X. Adhikari, V. B. Adya, C. Affeldt, D. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, T. Akutsu, Tiffany Z. Summerscales

Faculty Publications

We present a search for quasi-monochromatic gravitational-wave signals from the young, energetic X-ray pulsar PSR J0537-6910 using data from the second and third observing runs of LIGO and Virgo. The search is enabled by a contemporaneous timing ephemeris obtained using Neutron star Interior Composition Explorer (NICER) data. The NICER ephemeris has also been extended through 2020 October and includes three new glitches. PSR J0537-6910 has the largest spin-down luminosity of any pulsar and exhibits fRequent and strong glitches. Analyses of its long-term and interglitch braking indices provide intriguing evidence that its spin-down energy budget may include gravitational-wave emission from a …

Predicting The Spectrum Of Ugc 2885, Rubin’S Galaxy With Machine Learning, Benne Holwerda, John F. Wu, William C. Keel, Jason Young, Ren Mullins, Joannah Hinz, K. E. Saavik Ford, Pauline Barmby, Rupali Chandar, Jeremy Bailin, Josh Peek, Tim Pickering, Torsten Böker

Faculty and Staff Scholarship

Wu & Peek predict SDSS-quality spectra based on Pan-STARRS broadband grizy images using machine learning (ML). In this article, we test their prediction for a unique object, UGC 2885 ("Rubin's galaxy"), the largest and most massive, isolated disk galaxy in the local universe (D < 100 Mpc). After obtaining the ML predicted spectrum, we compare it to all existing spectroscopic information that is comparable to an SDSS spectrum of the central region: two archival spectra, one extracted from the VIRUS-P observations of this galaxy, and a new, targeted MMT/Binospec observation. Agreement is qualitatively good, though the ML prediction prefers line ratios slightly more toward those of an active galactic nucleus (AGN), compared to archival and VIRUS-P observed values. The MMT/Binospec nuclear spectrum unequivocally shows strong emission lines except Hβ, the ratios of which are consistent with AGN activity. The ML approach to galaxy spectra may be a viable way to identify AGN supplementing NIR colors. How such a massive disk galaxy (M* = 1011 M⊙), which uncharacteristically shows no sign of interaction or mergers, manages to fuel its central …