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Articles 1861 - 1890 of 8856

Full-Text Articles in Astrophysics and Astronomy

Maximum Temperatures In Evolving Protoplanetary Discs And Composition Of Planetary Building Blocks, Min Li, Shichun Huang, Zhaohuan Zhu, Michael I. Petaev, Jason H. Steffen Mar 2021

Maximum Temperatures In Evolving Protoplanetary Discs And Composition Of Planetary Building Blocks, Min Li, Shichun Huang, Zhaohuan Zhu, Michael I. Petaev, Jason H. Steffen

Geoscience Faculty Research

The maximum temperature and radial temperature profile in a protoplanetary disc are important for the condensation of different elements in the disc. We simulate the evolution of a set of protoplanetary discs from the collapse of their progenitor molecular cloud cores as well as the dust decoupling within the discs as they evolve. We show how the initial properties of the cloud cores affect the thermal history of the protoplanetary discs using a simple viscous disc model. Our results show that the maximum mid-plane temperature in the disc occurs within 0.5 au. It increases with the initial cloud temperature and …

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Evidence For X (3872) →J/Ψ Π+ Π-Produced In Single-Tag Two-Photon Interactions, Y. Teramoto, S. Uehara, M. Masuda, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, T. Aushev, R. Ayad, V. Babu, P. Behera, C. Belenõ, J. Bennett, V. Bhardwaj, B. Bhuyan, T. Bilka, J. Biswal, G. Bonvicini Mar 2021

Evidence For X (3872) →J/Ψ Π+ Π-Produced In Single-Tag Two-Photon Interactions, Y. Teramoto, S. Uehara, M. Masuda, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, T. Aushev, R. Ayad, V. Babu, P. Behera, C. Belenõ, J. Bennett, V. Bhardwaj, B. Bhuyan, T. Bilka, J. Biswal, G. Bonvicini

Faculty and Student Publications

We report the first evidence for X(3872) production in two-photon interactions by tagging either the electron or the positron in the final state, exploring the highly virtual photon region. The search is performed in e+e-→e+e-J/ψ π+ π-, using 825 fb-1 of data collected by the Belle detector operated at the KEKB e+e-collider. We observe three X(3872) candidates, where the expected background is 0.11±0.10 events, with a significance of 3.2σ. We obtain an estimated value for γB(X(3872)→J/ψ π+ π-) assuming the Q2 dependence predicted by a cc meson model, where-Q2 is the invariant mass squared of the virtual photon. No X(3915)→J/ψ …

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Computational Development Of A Miniature Quantum Dot Spectrometer For Use In Space, Joseph Richardson Mar 2021

Computational Development Of A Miniature Quantum Dot Spectrometer For Use In Space, Joseph Richardson

Undergraduate Honors Theses

Miniature spectrometers are of great interest to NASA as necessary instrumentation is scaled down and optimized for specific space application. Semiconductor nanocrystals called quantum dots (QD) are being used to create a miniature high-resolution filter-based spectrometer, with the goal of use in space within 5 years. Computational imaging techniques— such as automated image analysis and mathematical spectrum reconstruction algorithms—are key to making the QD spectrometer a reality. This thesis will discuss the process of developing these computational methods, along with the improvements that have occurred from previous work.

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Common-Spectrum Process Versus Cross-Correlation For Gravitational-Wave Searches Using Pulsar Timing Arrays, Joseph D. Romano, ‪Jeffrey S. Hazboun, X. Siemens, Anne M. Archibald Mar 2021

Common-Spectrum Process Versus Cross-Correlation For Gravitational-Wave Searches Using Pulsar Timing Arrays, Joseph D. Romano, ‪Jeffrey S. Hazboun, X. Siemens, Anne M. Archibald

Physics & Astronomy Faculty Publications

The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has recently reported strong statistical evidence for a common-spectrum red-noise process for all pulsars, as seen in their 12.5-yr analysis for an isotropic stochastic gravitational-wave signal. However, there is currently very little evidence for quadrupolar spatial correlations across the pulsars in the array, which is needed to make a confident claim of detection of a stochastic gravitational-wave background. In this paper, we provide a “back-of-the-envelope” illustration of the NANOGrav 12.5-yr results for the nonexpert reader, using a very simple signal+noise model and frequentist statistics. We show that the current lack of …

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A Gravitational-Wave Measurement Of The Hubble Constant Following The Second Observing Run Of Advanced Ligo And Virgo, Ligo Scientific Collaboration, Virgo Collaboration, Tiffany Z. Summerscales Mar 2021

A Gravitational-Wave Measurement Of The Hubble Constant Following The Second Observing Run Of Advanced Ligo And Virgo, Ligo Scientific Collaboration, Virgo Collaboration, Tiffany Z. Summerscales

Faculty Publications

This paper presents the gravitational-wave measurement of the Hubble constant (H0) using the detections from the first and second observing runs of the Advanced LIGO and Virgo detector network. The presence of the transient electromagnetic counterpart of the binary neutron star GW170817 led to the first standard-siren measurement of H0. Here we additionally use binary black hole detections in conjunction with galaxy catalogs and report a joint measurement. Our updated measurement is H0 = km s−1 Mpc−1 (68.3% of the highest density posterior interval with a flat-in-log prior) which is an improvement by a factor of …

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Acoustic Orbital Angular Momentum Hall Effect And Realization Using A Metasurface, Xu Dong Fan, Likun Zhang Mar 2021

Acoustic Orbital Angular Momentum Hall Effect And Realization Using A Metasurface, Xu Dong Fan, Likun Zhang

Faculty and Student Publications

Vortex beams with a twisted wavefront possess both intrinsic and extrinsic orbital angular momenta. Their coupling (viz. orbital-orbital coupling) leads to an orbital angular momentum Hall effect previously found in light, providing applications in light manipulation. Here an analogous orbital Hall effect in acoustics is reported via modeling vortex beam propagation in an inhomogeneous medium. A shift of the beam center perpendicular to the inhomogeneous direction is numerically observed to follow a path predicted by ray theory in the weak inhomogeneity approximation where the coupling and conservation of total angular momenta are identified. Experimental observation of the acoustic phenomenon with …

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Frequentist Versus Bayesian Analyses: Cross-Correlation As An Approximate Sufficient Statistic For Ligo-Virgo Stochastic Background Searches, Andrew Matas, Joseph D. Romano Mar 2021

Frequentist Versus Bayesian Analyses: Cross-Correlation As An Approximate Sufficient Statistic For Ligo-Virgo Stochastic Background Searches, Andrew Matas, Joseph D. Romano

Physics & Astronomy Faculty Publications

Sufficient statistics are combinations of data in terms of which the likelihood function can be rewritten without loss of information. Depending on the data volume reduction, the use of sufficient statistics as a preliminary step in a Bayesian analysis can lead to significant increases in efficiency when sampling from posterior distributions of model parameters. Here we show that the frequency integrand of the cross-correlation statistic and its variance are approximate sufficient statistics for ground-based searches for stochastic gravitational-wave backgrounds. The sufficient statistics are approximate because one works in the weak-signal approximation and uses measured estimates of the autocorrelated power in …

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Measurement Of Branching Fractions Of Λc+ →Η Λπ+, Η Σ0Π+, Λ (1670)Π+, And Η Σ (1385)+, J. Y. Lee, K. Tanida, Y. Kato, S. K. Kim, S. B. Yang, I. Adachi, J. K. Ahn, H. Aihara, S. Al Said, D. M. Asner, T. Aushev, R. Ayad, V. Babu, S. Bahinipati, P. Behera, C. Beleño, J. Bennett, M. Bessner, B. Bhuyan Mar 2021

Measurement Of Branching Fractions Of Λc+ →Η Λπ+, Η Σ0Π+, Λ (1670)Π+, And Η Σ (1385)+, J. Y. Lee, K. Tanida, Y. Kato, S. K. Kim, S. B. Yang, I. Adachi, J. K. Ahn, H. Aihara, S. Al Said, D. M. Asner, T. Aushev, R. Ayad, V. Babu, S. Bahinipati, P. Behera, C. Beleño, J. Bennett, M. Bessner, B. Bhuyan

Faculty and Student Publications

We report branching fraction measurements of four decay modes of the Λc+ baryon, each of which includes an η meson and a Λ baryon in the final state, and all of which are measured relative to the Λc+→pK-π+ decay mode. The results are based on a 980 fb-1 data sample collected by the Belle detector at the KEKB asymmetric-energy e+e- collider. Two decays, Λc+→ης0π+ and Λ(1670)π+, are observed for the first time, while the measurements of the other decay modes, Λc+→ηΛπ+ and ης(1385)+, are more precise than those made previously. We obtain relative branching fractions of B(Λc+→ηΛπ+)/B(Λc+→pK-π+)=0.293±0.003±0.014, B(Λc+→ης0π+)/B(Λc+→pK-π+)=0.120±0.006±0.010, B(Λc+→Λ(1670)π+)×B(Λ(1670)→ηΛ)/B(Λc+→pK-π+)=(5.54±0.29±0.73)×10-2, and …

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Identifying, Analyzing, And Using Discriminatory Variables For Classification Of Neutrino Signal And Background Noise In Multivariate Analysis In The Askaryan Radio Array Experiment, Jesse Osborn Mar 2021

Identifying, Analyzing, And Using Discriminatory Variables For Classification Of Neutrino Signal And Background Noise In Multivariate Analysis In The Askaryan Radio Array Experiment, Jesse Osborn

Honors Program: Senior Projects (Public)

The Askaryan Radio Array Experiment, located near the South Pole, works to pinpoint specific instances of neutrinos from outside the solar system interacting with nucleons inside the Antarctic ice, emitting radio waves. I have taken data from the ARA stations which is presumed to be background noise and compared it to simulated data meant to look like a neutrino signal. I developed a suite of variables for discrimination between the two data sets, using a computer algorithm to generate a single output variable which can be used to distinguish noise events from signal events. I maximized this discrimination process for …

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All-Sky Search In Early O3 Ligo Data For Continuous Gravitational-Wave Signals From Unknown Neutron Stars In Binary Systems, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, K. E. Ramirez, W. H. Wang Mar 2021

All-Sky Search In Early O3 Ligo Data For Continuous Gravitational-Wave Signals From Unknown Neutron Stars In Binary Systems, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, K. E. Ramirez, W. H. Wang

Physics & Astronomy Faculty Publications

Rapidly spinning neutron stars are promising sources of continuous gravitational waves. Detecting such a signal would allow probing of the physical properties of matter under extreme conditions. A significant fraction of the known pulsar population belongs to binary systems. Searching for unknown neutron stars in binary systems requires specialized algorithms to address unknown orbital frequency modulations. We present a search for continuous gravitational waves emitted by neutron stars in binary systems in early data from the third observing run of the Advanced LIGO and Advanced Virgo detectors using the semicoherent, GPU-accelerated, BinarySkyHough pipeline. The search analyzes the most sensitive frequency …

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All-Sky Search In Early O3 Ligo Data For Continuous Gravitational-Wave Signals From Unknown Neutron Stars In Binary Systems, 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, K. M. Aleman, Tiffany Summerscales Mar 2021

All-Sky Search In Early O3 Ligo Data For Continuous Gravitational-Wave Signals From Unknown Neutron Stars In Binary Systems, 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, K. M. Aleman, Tiffany Summerscales

Faculty Publications

Rapidly spinning neutron stars are promising sources of continuous gravitational waves. Detecting such a signal would allow probing of the physical properties of matter under extreme conditions. A significant fraction of the known pulsar population belongs to binary systems. Searching for unknown neutron stars in binary systems requires specialized algorithms to address unknown orbital frequency modulations. We present a search for continuous gravitational waves emitted by neutron stars in binary systems in early data from the third observing run of the Advanced LIGO and Advanced Virgo detectors using the semicoherent, GPU-accelerated, binaryskyhough pipeline. The search analyzes the most sensitive frequency …

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All-Sky Search In Early O3 Ligo Data For Continuous Gravitational-Wave Signals From Unknown Neutron Stars In Binary Systems, Ligo Scientific Collaboration, Virgo Collaboration, Tiffany Z. Summerscales Mar 2021

All-Sky Search In Early O3 Ligo Data For Continuous Gravitational-Wave Signals From Unknown Neutron Stars In Binary Systems, Ligo Scientific Collaboration, Virgo Collaboration, Tiffany Z. Summerscales

Faculty Publications

Rapidly spinning neutron stars are promising sources of continuous gravitational waves. Detecting such a signal would allow probing of the physical properties of matter under extreme conditions. A significant fraction of the known pulsar population belongs to binary systems. Searching for unknown neutron stars in binary systems requires specialized algorithms to address unknown orbital frequency modulations. We present a search for continuous gravitational waves emitted by neutron stars in binary systems in early data from the third observing run of the Advanced LIGO and Advanced Virgo detectors using the semicoherent, GPU-accelerated, binaryskyhough pipeline. The search analyzes the most sensitive frequency …

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A Gravitational-Wave Measurement Of The Hubble Constant Following The Second Observing Run Of Advanced Ligo And Virgo, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Karla E. Ramirez, Satzhan Sitmukhambetov, Robert Stone, D. Tuyenbayev, Wenhui Wang, Adam Zadrozny Mar 2021

A Gravitational-Wave Measurement Of The Hubble Constant Following The Second Observing Run Of Advanced Ligo And Virgo, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Karla E. Ramirez, Satzhan Sitmukhambetov, Robert Stone, D. Tuyenbayev, Wenhui Wang, Adam Zadrozny

Physics & Astronomy Faculty Publications

This paper presents the gravitational-wave measurement of the Hubble constant (H0) using the detections from the first and second observing runs of the Advanced LIGO and Virgo detector network. The presence of the transient electromagnetic counterpart of the binary neutron star GW170817 led to the first standard-siren measurement of H0. Here we additionally use binary black hole detections in conjunction with galaxy catalogs and report a joint measurement. Our updated measurement is H0 = - 69+8 16 km s−1 Mpc−1 (68.3% of the highest density posterior interval with a flat-in-log prior) which is an improvement by a factor of 1.04 …

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Updated Miniboone Neutrino Oscillation Results With Increased Data And New Background Studies, A. A. Aguilar-Arevalo, B. C. Brown, J. M. Conrad, R. Dharmapalan, A. Diaz, Z. Djurcic, D. A. Finley, R. Ford, G. T. Garvey, S. Gollapinni, A. Hourlier, E-C Huang, N. W. Kamp, G. Karagiorgi, T. Katori, T. Kobilarcik, K. Lin, W. C. Louis, C. Mariani, W. Marsh, G. B. Mills, J. Mirabal-Martinez, C. D. Moore, R. H. Nelson, J. Nowak, I Parmaksiz, Z. Pavlovic, H. Ray, B. P. Roe, A. D. Russell, A. Schneider, M. H. Shaevitz, H. Siegel, J. Spitz, I. Stancu, R. Tayloe, R. T. Thornton, M. Tzanov, R. G. Van De Water, D. H. White, E. D. Zimmerman Mar 2021

Updated Miniboone Neutrino Oscillation Results With Increased Data And New Background Studies, A. A. Aguilar-Arevalo, B. C. Brown, J. M. Conrad, R. Dharmapalan, A. Diaz, Z. Djurcic, D. A. Finley, R. Ford, G. T. Garvey, S. Gollapinni, A. Hourlier, E-C Huang, N. W. Kamp, G. Karagiorgi, T. Katori, T. Kobilarcik, K. Lin, W. C. Louis, C. Mariani, W. Marsh, G. B. Mills, J. Mirabal-Martinez, C. D. Moore, R. H. Nelson, J. Nowak, I Parmaksiz, Z. Pavlovic, H. Ray, B. P. Roe, A. D. Russell, A. Schneider, M. H. Shaevitz, H. Siegel, J. Spitz, I. Stancu, R. Tayloe, R. T. Thornton, M. Tzanov, R. G. Van De Water, D. H. White, E. D. Zimmerman

Faculty Publications

The MiniBooNE experiment at Fermilab reports a total excess of 638.0 +/- 52.1(stat) +/- 122.2(syst) electronlike events from a data sample corresponding to 18.75 x 10(20) protons-on-target in neutrino mode, which is a 46% increase in the data sample with respect to previously published results and 11.27 x 10(20) protons-on-target in antineutrino mode. The overall significance of the excess, 4.8 sigma, is limited by systematic uncertainties, assumed to be Gaussian, as the statistical significance of the excess is 12.2 sigma. The additional statistics allow several studies to address questions on the source of the excess. First, we provide two-dimensional plots …

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Implications Of An Improved Water Equation Of State For Water-Rich Planets, Chenling Huang, David R. Rice, Zachary M. Grande, Dean Smith, John H. Boisvert, Oliver Tschauner, Ashkan Salamat, Jason Steffen Mar 2021

Implications Of An Improved Water Equation Of State For Water-Rich Planets, Chenling Huang, David R. Rice, Zachary M. Grande, Dean Smith, John H. Boisvert, Oliver Tschauner, Ashkan Salamat, Jason Steffen

Geoscience Faculty Research

Water (H2O), in all forms, is an important constituent in planetary bodies, controlling habitability and influencing geological activity. Under conditions found in the interior of many planets, as the pressure increases, the H-bonds in water gradually weaken and are replaced by ionic bonds. Recent experimental measurements of the water equation of state (EOS) showed both a new phase of H-bonded water ice, ice-VIIt, and a relatively low transition pressure just above 30 GPa to ionic bonded ice-X, which has a bulk modulus 2.5 times larger. The higher bulk modulus of ice-X produces larger planets for a given mass, thereby either …

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Celebrating The Mars Landings, Erik Johnson Mar 2021

Celebrating The Mars Landings, Erik Johnson

Natural Science Faculty

Last month, three robotic missions launched from different countries reached Mars, including the first successful missions sent by China and the United Arab Emirates. Along with Tianwen-1 and Hope, NASA sent a rover to Mars named Perseverance, which will soon deploy a helicopter named Ingenuity. To celebrate these arrivals, the staff of the William M. Staerkel Planetarium at Parkland College offered a series of virtual programs and videos that are still available to the public.

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A Nearby Transiting Rocky Exoplanet That Is Suitable For Atmospheric Investigation, T. Trifonov, J. A. Caballero, J. C. Morales, A. Seifahrt, I. Ribas, A. Reiners, J. L. Bean, R. Luque, H. Parviainen, E. Pallé, S. Stock, M. Zechmeister, P. J. Amado, G. Anglada-Escudé, M. Azzaro, T. Barclay, V. J. S. Béjar, P. Bluhm, N. Casasayas-Barris, C. Cifuentes, K. A. Collins, K. I. Collins, M. Cortés-Contreras, J. De Leon, S. Dreizler, C. D. Dressing, E. Esparza-Borges, N. Espinoza, M. Fausnaugh, A. Fukui, A. P. Hatzes, C. Hellier, T. Henning, C. E. Henze, E. Herrero, S. V. Jeffers, J. M. Jenkins, Eric L.N. Jensen, A. Kaminski, D. Kasper, D. Kossakowski, M. Kürster, M. Lafarga, D. W. Latham, A. W. Mann, K. Molaverdikhani, D. Montes, B. T. Montet, F. Murgas, N. Narita, M. Oshagh, V. M. Passegger, D. Pollacco, S. N. Quinn, A. Quirrenbach, G. R. Ricker, C. Rodríguez López, J. Sanz-Forcada, R. P. Schwarz, A. Schweitzer, S. Seager, A. Shporer, M. Stangret, J. Stürmer, T. G. Tan, P. Tenenbaum, J. D. Twicken, R. Vanderspek, J. N. Winn Mar 2021

A Nearby Transiting Rocky Exoplanet That Is Suitable For Atmospheric Investigation, T. Trifonov, J. A. Caballero, J. C. Morales, A. Seifahrt, I. Ribas, A. Reiners, J. L. Bean, R. Luque, H. Parviainen, E. Pallé, S. Stock, M. Zechmeister, P. J. Amado, G. Anglada-Escudé, M. Azzaro, T. Barclay, V. J. S. Béjar, P. Bluhm, N. Casasayas-Barris, C. Cifuentes, K. A. Collins, K. I. Collins, M. Cortés-Contreras, J. De Leon, S. Dreizler, C. D. Dressing, E. Esparza-Borges, N. Espinoza, M. Fausnaugh, A. Fukui, A. P. Hatzes, C. Hellier, T. Henning, C. E. Henze, E. Herrero, S. V. Jeffers, J. M. Jenkins, Eric L.N. Jensen, A. Kaminski, D. Kasper, D. Kossakowski, M. Kürster, M. Lafarga, D. W. Latham, A. W. Mann, K. Molaverdikhani, D. Montes, B. T. Montet, F. Murgas, N. Narita, M. Oshagh, V. M. Passegger, D. Pollacco, S. N. Quinn, A. Quirrenbach, G. R. Ricker, C. Rodríguez López, J. Sanz-Forcada, R. P. Schwarz, A. Schweitzer, S. Seager, A. Shporer, M. Stangret, J. Stürmer, T. G. Tan, P. Tenenbaum, J. D. Twicken, R. Vanderspek, J. N. Winn

Physics & Astronomy Faculty Works

Spectroscopy of transiting exoplanets can be used to investigate their atmospheric properties and habitability. Combining radial velocity (RV) and transit data provides additional information on exoplanet physical properties. We detect a transiting rocky planet with an orbital period of 1.467 days around the nearby red dwarf star Gliese 486. The planet Gliese 486 b is 2.81 Earth masses and 1.31 Earth radii, with uncertainties of 5%, as determined from RV data and photometric light curves. The host star is at a distance of ~8.1 parsecs, has a J-band magnitude of ~7.2, and is observable from both hemispheres of Earth. On …

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Crafts For Fast Radio Bursts: Extending The Dispersion-Fluence Relation With New Frbs Detected By Fast, Chen Hui Niu, Di Li, Rui Luo, Wei Yang Wang, Jumei Yao, Bing Zhang, Wei Wei Zhu, Pei Wang, Haoyang Ye, Yong Kun Zhang, Jia Rui Niu, Ning Yu Tang, Ran Duan, Marko Krco, Shi Dai, Yi Feng, Chenchen Miao, Zhichen Pan, Lei Qian, Mengyao Xue, Mao Yuan, Youling Yue, Lei Zhang, Xinxin Zhang Mar 2021

Crafts For Fast Radio Bursts: Extending The Dispersion-Fluence Relation With New Frbs Detected By Fast, Chen Hui Niu, Di Li, Rui Luo, Wei Yang Wang, Jumei Yao, Bing Zhang, Wei Wei Zhu, Pei Wang, Haoyang Ye, Yong Kun Zhang, Jia Rui Niu, Ning Yu Tang, Ran Duan, Marko Krco, Shi Dai, Yi Feng, Chenchen Miao, Zhichen Pan, Lei Qian, Mengyao Xue, Mao Yuan, Youling Yue, Lei Zhang, Xinxin Zhang

Physics & Astronomy Faculty Research

We report three new FRBs discovered by the Five-hundred-meter Aperture Spherical radio Telescope (FAST), namely FRB 181017.J0036+11, FRB 181118, and FRB 181130, through the Commensal Radio Astronomy FAST Survey (CRAFTS). Together with FRB 181123, which was reported earlier, all four FAST-discovered FRBs share the same characteristics of low fluence (≤0.2 Jy ms) and high dispersion measure (DM, >1000 pc cm-3), consistent with the anticorrelation between DM and fluence of the entire FRB population. FRB 181118 and FRB 181130 exhibit band-limited features. FRB 181130 is prominently scattered (τ s ≃ 8 ms) at 1.25 GHz. FRB 181017.J0036+11 has full-bandwidth emission with …

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Redefining Nietzsche’S Greatest Weight Into Contemporary Cosmology, Christian E. Coffinet-Crean Mar 2021

Redefining Nietzsche’S Greatest Weight Into Contemporary Cosmology, Christian E. Coffinet-Crean

Scholarly Horizons: University of Minnesota, Morris Undergraduate Journal

Friedrich Nietzsche’s theory of eternal recurrence and it’s cosmological value has been discredited and cast aside because of the lack of scientific backing the original theory had. In this essay, Nietzche’s eternal recurrence will be observed and analyzed through some of his major works and defended from outside criticism. Furthermore, Roger Penrose’s Conformal Cyclic Cosmology and Jean-Paul Luminet’s research are used in support for eternal recurrence as a cosmological theory. Luminet’s research of cosmic background radiation concludes that the universe has an odd but finite shape. Penrose’s research theorizes a sort of repeating universe, allowing time to be treated as …

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Test Of Lepton Flavor Universality And Search For Lepton Flavor Violation In B → Kℓℓ Decays, S. Choudhury, S. Sandilya, K. Trabelsi, A. Giri, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, S. Bahinipati, P. Behera, C. Beleño, K. Belous, J. Bennett, F. Bernlochner, M. Bessner Mar 2021

Test Of Lepton Flavor Universality And Search For Lepton Flavor Violation In B → Kℓℓ Decays, S. Choudhury, S. Sandilya, K. Trabelsi, A. Giri, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, S. Bahinipati, P. Behera, C. Beleño, K. Belous, J. Bennett, F. Bernlochner, M. Bessner

Faculty and Student Publications

We present measurements of the branching fractions for the decays B → Kμ+μ− and B → Ke+e−, and their ratio (RK), using a data sample of 711 fb−1 that contains 772 × 106BB¯ events. The data were collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. The ratio RK is measured in five bins of dilepton invariant-mass-squared (q2): q2 ∈ (0.1, 4.0), (4.00, 8.12), (1.0, 6.0), (10.2, 12.8) and (> 14.18) GeV2/c4, along with the whole q2 region. The RK value for q2 ∈ (1.0, 6.0) GeV2/c4 is 1.03−0.24+0.28 ± 0.01. The first and …

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Gibbs Point Process Model For Young Star Clusters In M33, Dayi Li, Pauline Barmby Mar 2021

Gibbs Point Process Model For Young Star Clusters In M33, Dayi Li, Pauline Barmby

Physics and Astronomy Publications

We demonstrate the power of Gibbs point process models from the spatial statistics literature when applied to studies of resolved galaxies. We conduct a rigorous analysis of the spatial distributions of objects in the star formation complexes of M33, including giant molecular clouds (GMCs) and young stellar cluster candidates (YSCCs). We choose a hierarchical model structure from GMCs to YSCCs based on the natural formation hierarchy between them. This approach circumvents the limitations of the empirical two-point correlation function analysis by naturally accounting for the inhomogeneity present in the distribution of YSCCs. We also investigate the effects of GMCs' properties …

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Constraining The Nature Of The Pds 70 Protoplanets With Vlti/Gravity, J. J. Wang, A. Vigan, S. Lacour, M. Nowak, T. Stolker, R. J. De Rosa, S. Ginzburg, P. Gao, R. Abuter, A. Amorim, R. Asensio-Torres, M. Bauböck, M. Benisty, J. P. Berger, H. Beust, J. L. Beuzit, S. Blunt, A. Boccaletti, A. Bohn, M. Bonnefoy, H. Bonnet, W. Brandner, F. Cantalloube, P. Caselli, B. Charnay, G. Chauvin, E. Choquet, V. Christiaens, Y. Clénet, V. Coudé Du Foresto, A. Cridland, P. T. De Zeeuw, K. Ward-Duong, Et Al Mar 2021

Constraining The Nature Of The Pds 70 Protoplanets With Vlti/Gravity, J. J. Wang, A. Vigan, S. Lacour, M. Nowak, T. Stolker, R. J. De Rosa, S. Ginzburg, P. Gao, R. Abuter, A. Amorim, R. Asensio-Torres, M. Bauböck, M. Benisty, J. P. Berger, H. Beust, J. L. Beuzit, S. Blunt, A. Boccaletti, A. Bohn, M. Bonnefoy, H. Bonnet, W. Brandner, F. Cantalloube, P. Caselli, B. Charnay, G. Chauvin, E. Choquet, V. Christiaens, Y. Clénet, V. Coudé Du Foresto, A. Cridland, P. T. De Zeeuw, K. Ward-Duong, Et Al

Astronomy: Faculty Publications

We present K-band interferometric observations of the PDS 70 protoplanets along with their host star using VLTI/ GRAVITY. We obtained K-band spectra and 100 μas precision astrometry of both PDS 70 b and c in two epochs, as well as spatially resolving the hot inner disk around the star. Rejecting unstable orbits, we found a nonzero eccentricity for PDS 70 b of 0.17 ± 0.06, a near-circular orbit for PDS 70 c, and an orbital configuration that is consistent with the planets migrating into a 2:1 mean motion resonance. Enforcing dynamical stability, we obtained a 95% upper limit on the …

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Dynamical Modelling Of Cxogbs J175553.2-281633: A 10 H Long Orbital Period Cataclysmic Variable, Sebastian Gomez, Manuel A. P. Torres, Peter G. Jonker, Zuzanna Kostrzewa-Rutkowska, Theo F. J. Van Grunsven, Andrzej Udalski, Robert I. Hynes, Craig O. Heinke, Thomas J. Maccarone, Ricardo Salinas, Jay Strader Mar 2021

Dynamical Modelling Of Cxogbs J175553.2-281633: A 10 H Long Orbital Period Cataclysmic Variable, Sebastian Gomez, Manuel A. P. Torres, Peter G. Jonker, Zuzanna Kostrzewa-Rutkowska, Theo F. J. Van Grunsven, Andrzej Udalski, Robert I. Hynes, Craig O. Heinke, Thomas J. Maccarone, Ricardo Salinas, Jay Strader

Faculty Publications

We present modelling of the long-term optical light and radial velocity curves of the binary stellar system CXOGBS J175553.2-281633, first detected in X-rays in the Chandra Galactic Bulge Survey. We analysed 7 yr of optical I-band photometry from Optical Gravitational Lensing Experiment and found long-term variations from year to year. These long-term variations can most likely be explained with by either variations in the luminosity of the accretion disc or a spotted secondary star. The phased light curve has a sinusoidal shape, which we interpret as being due to ellipsoidal modulations. We improve the orbital period to be P = …

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Planet Hunters Tess Ii: Findings From The First Two Years Of Tess, N. L. Eisner, O. Barragan, C. Lintott, S. Aigrain, B. Nicholson, T. S. Boyajian, S. Howell, C. Johnston, B. Lakeland, G. Miller, A. Mcmaster, H. Parviainen, E. J. Safron, M. E. Schwamb, L. Trouille, S. Vaughan, N. Zicher, C. Allen, S. Allen, M. Bouslog, C. Johnson, M. N. Simon, Z. Wolfenbarger, E. M. L. Baeten, D. M. Bundy, T. Hoffman Mar 2021

Planet Hunters Tess Ii: Findings From The First Two Years Of Tess, N. L. Eisner, O. Barragan, C. Lintott, S. Aigrain, B. Nicholson, T. S. Boyajian, S. Howell, C. Johnston, B. Lakeland, G. Miller, A. Mcmaster, H. Parviainen, E. J. Safron, M. E. Schwamb, L. Trouille, S. Vaughan, N. Zicher, C. Allen, S. Allen, M. Bouslog, C. Johnson, M. N. Simon, Z. Wolfenbarger, E. M. L. Baeten, D. M. Bundy, T. Hoffman

Faculty Publications

We present the results from the first two years of the Planet Hunters TESS (PHT) citizen science project, which identifies planet candidates in the TESS (Transiting Exoplanet Survey Satellite) data by engaging members of the general public. Over 22000 citizen scientists from around the world visually inspected the first 26 sectors of TESS data in order to help identify transit-like signals. We use a clustering algorithm to combine these classifications into a ranked list of events for each sector, the top 500 of which are then visually vetted by the science team. We assess the detection efficiency of this methodology …

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Studying The Conditions For Magnetic Reconnection In Solar Flares With And Without Precursor Flares, Seth H. Garland Mar 2021

Studying The Conditions For Magnetic Reconnection In Solar Flares With And Without Precursor Flares, Seth H. Garland

Theses and Dissertations

Forecasting of solar flares remains a challenge due to the limited understanding of the triggering mechanisms associated with magnetic reconnection, the primary physical phenomenon connected to these events. Consequently, methods continue to rely on the climatology of solar flare events as opposed to the underlying physics principles. Models of magnetic reconnection in the solar atmosphere places the null point of the reconnection within the corona. Though as of now the coronal magnetic field cannot be directly measured, the field is tied to the photospheric magnetic field, which can be. This study utilized data from the Solar Dynamics Observatory Helioseismic and …

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How And Why Mars Lost Its Water, Sana Akhter, Andre Beikircher Feb 2021

How And Why Mars Lost Its Water, Sana Akhter, Andre Beikircher

2021 Honors Council of the Illinois Region

The topic of this paper is to investigate how and why Mars lost its water. It is important to study the loss of water on Mars because it can give us a better understanding of how Mars once looked, if life were possible, and how it could have changed so drastically to what it is now. The paper aims to address which factors led to Mars losing its water and how long ago this happened. Using our data, we will predict how quickly Mars’ core cooled, when its magnetic field weakened, and when the water was lost. We learned that …

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Quasinormal Modes And Their Overtones At The Common Horizon In A Binary Black Hole Merger, Pierre Mourier, Xisco Jimenez Forteza, Daniel Pook-Kolb, Dadri Krishnan, Erik Schnetter Feb 2021

Quasinormal Modes And Their Overtones At The Common Horizon In A Binary Black Hole Merger, Pierre Mourier, Xisco Jimenez Forteza, Daniel Pook-Kolb, Dadri Krishnan, Erik Schnetter

Faculty Publications

It is expected that all astrophysical black holes in equilibrium are well described by the Kerr solution. Moreover, any black hole far away from equilibrium, such as one initially formed in a compact binary merger or by the collapse of a massive star, will eventually reach a final equilibrium Kerr state. At sufficiently late times in this process of reaching equilibrium, we expect that the black hole is modeled as a perturbation around the final state. The emitted gravitational waves will then be damped sinusoids with frequencies and damping times given by the quasinormal mode spectrum of the final Kerr …

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Differential Cross Sections For Λ(1520) Using Photoproduction At Clas, U. Shrestha, T. Chetry, C. Djalali, K. Hicks, S. I. Nam, K. P. Adhikari, M. Amaryan, G. Angelini, H. Atac, L. Barion, M. Battaglieri, I. Bedlinskiy, F. Benmokhtar, A. Bianconi, A. S. Biselli, M. Bondi, F. Bossú, S. Boiarinov, W. J. Briscoe, W. K. Brooks, Steffen Strauch, Et. Al. Feb 2021

Differential Cross Sections For Λ(1520) Using Photoproduction At Clas, U. Shrestha, T. Chetry, C. Djalali, K. Hicks, S. I. Nam, K. P. Adhikari, M. Amaryan, G. Angelini, H. Atac, L. Barion, M. Battaglieri, I. Bedlinskiy, F. Benmokhtar, A. Bianconi, A. S. Biselli, M. Bondi, F. Bossú, S. Boiarinov, W. J. Briscoe, W. K. Brooks, Steffen Strauch, Et. Al.

Faculty Publications

The reaction 𝛾⁢𝑝→𝐾+⁢Λ⁡(1520) using photoproduction data from the CLAS 𝑔⁡12 experiment at Jefferson Lab is studied. The decay of Λ⁡(1520) into two exclusive channels, Σ+⁢𝜋− and Σ−⁢𝜋+, is studied from the detected 𝐾+, 𝜋+, and 𝜋− particles. A good agreement is established for the Λ⁡(1520) differential cross sections with the previous CLAS measurements. The differential cross sections as a function of center-of-mass angle are extended to higher photon energies. Newly added are the differential cross sections as a function of invariant four-momentum transfer 𝑡, which is the natural variable to use for a theoretical model based on a Regge-exchange reaction …

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The Pencil Code, A Modular Mpi Code For Partial Differential Equations And Particles: Multipurpose And Multiuser-Maintained, The Pencil Code Collaboration, Chao-Chin Yang Feb 2021

The Pencil Code, A Modular Mpi Code For Partial Differential Equations And Particles: Multipurpose And Multiuser-Maintained, The Pencil Code Collaboration, Chao-Chin Yang

Physics & Astronomy Faculty Research

The Pencil Code is a highly modular physics-oriented simulation code that can be adapted to a wide range of applications. It is primarily designed to solve partial differential equations (PDEs) of compressible hydrodynamics and has lots of add-ons ranging from astrophysical magnetohydrodynamics (MHD) (A. Brandenburg & Dobler, 2010) to meteorological cloud microphysics (Li et al., 2017) and engineering applications in combustion (Babkovskaia et al., 2011). Nevertheless, the framework is general and can also be applied to situations not related to hydrodynamics or even PDEs, for example when just the message passing interface or input/output strategies of the code are to …

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Dft Study Of “Unlayered Graphene Solid” Formation, In Liquid Carbon Droplets At Low Pressures, Chathuri Silva, Philip Chrostoski, Phil Fraundorf Feb 2021

Dft Study Of “Unlayered Graphene Solid” Formation, In Liquid Carbon Droplets At Low Pressures, Chathuri Silva, Philip Chrostoski, Phil Fraundorf

Physics Faculty Works

This atomistic modeling study is companion to new experimental work on carbon vapor slow-cooled in (a) the laboratory and (b) the atmosphere of ancient carbon-synthesizing stars. It specifically follows up on TEM clues about the nucleation of unlayered graphene sheets in a solidifying carbon liquid, to show that 5 atom loops may help explain evidence for faceted pentacones in a slow-cooled melt. This is also first in a series of modeling studies that may open the door to laboratory studies of (i) condensation in cool-giant star atmospheres and (ii) liquid carbon at low pressures.

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