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Astrophysics and Astronomy

2021

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Articles 301 - 330 of 430

Full-Text Articles in Physical Sciences and Mathematics

Monitoring The Night Sky For Iceact, Andre Sierra Alderete, John W. Hewitt, Warren Huelsnitz Apr 2021

Monitoring The Night Sky For Iceact, Andre Sierra Alderete, John W. Hewitt, Warren Huelsnitz

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

The neutral subatomic neutrinos are astronomical messengers that can provide us information to investigate the most violent astrophysical sources: supernovas, gamma-ray bursts, and cataclysmic phenomena involving black holes and neutron stars. As these astrophysical neutrinos freely travel from their point of origin without being scattered by interstellar magnetic fields, we can analyze these particles by observing cosmic-ray air showers on the Earth’s atmosphere. These are produced by the energetic neutrinos by interacting with the air particles that produce a wavefront of Cherenkov radiation. To better identify these background neutrinos, IceCube, the South Pole Neutrino Observatory, constructed an imaging air Cherenkov …

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Phenomenology Of Fermion Production During Axion Inflation, Michael Roberts Apr 2021

Phenomenology Of Fermion Production During Axion Inflation, Michael Roberts

Doctoral Dissertations

We study the production of fermions through a derivative coupling to an axion inflaton and the effects of the produced fermions on the scalar and tensor metric perturbations. We show how such a coupling can arise naturally from supergravity with an axion-like field driving large-field inflation and small instanton-like corrections. We present analytic results for the scalar and tensor power spectra, and estimate the amplitude of the non-Gaussianties in the equilateral regime. The scalar spectrum is found to have a red-tilted spectral index, small non-Gaussianities, and can be dominant over the vacuum contribution. In contrast, the tensor power spectrum from …

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Formation Of Supermassive Black Holes In The Early Universe, Arpan Das Apr 2021

Formation Of Supermassive Black Holes In The Early Universe, Arpan Das

Electronic Thesis and Dissertation Repository

The aim of the work presented in this thesis is to understand the formation and growth of the seeds of the supermassive black holes in early universe. Supermassive black holes (SMBH) with masses larger than 108MSun have been observed when the Universe was only 800 Myr old. The formation and accretion history of the seeds of these supermassive black holes are a matter of debate. We consider the scenario of massive seed black hole formation which allows gas to directly collapse into a black hole (DCBH) of similar mass. Considering this scenario, we show that the mass …

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Gorgonians Are Foundation Species On Sponge-Dominated Mesophotic Coral Reefs In The Caribbean, Marc Slattery, Michael P. Lesser Apr 2021

Gorgonians Are Foundation Species On Sponge-Dominated Mesophotic Coral Reefs In The Caribbean, Marc Slattery, Michael P. Lesser

Faculty and Student Publications

Foundation species (FS) regulate ecological processes within communities often facilitating biodiversity and habitat complexity. Typically FS are dominant structure-forming taxa; but less dominant taxa having disproportionate ecological impacts to the community can also be FS. Mesophotic coral ecosystems (MCEs) are deep coral reef (∼30–150 m) communities, often dominated by emergent sponges in the Caribbean Basin. Despite the potential competitive advantage of sponges on MCEs, gorgonians are also common constituents of these reefs. Data from the Bahamas demonstrate increased biodiversity and densities of sponges on mesophotic reefs with gorgonians relative to reefs without these species. Drawing upon fifteen years of field …

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The Role Of Hydrated Minerals And Space Weathering Products In The Bluing Of Carbonaceous Asteroids, David Trang, Michelle S. Thompson, Bet E. Clark, Hannah H. Kaplan, Xiao-Duan Zou, Jian-Yang Li, Salvatore M. Ferrone, Victoria E. Hamilton, Amy A. Simon, Dennis C. Reuter, Lindsay P. Keller, M. Antonietta Barucci, Humberto Campins, Cateline Lantz, Daniella N. Dellagiustina, Ronald-Louis Ballouz, Erica R. Jawin, Harold Connolly Jr., Kevin J. Walsh, Dante Lauretta Apr 2021

The Role Of Hydrated Minerals And Space Weathering Products In The Bluing Of Carbonaceous Asteroids, David Trang, Michelle S. Thompson, Bet E. Clark, Hannah H. Kaplan, Xiao-Duan Zou, Jian-Yang Li, Salvatore M. Ferrone, Victoria E. Hamilton, Amy A. Simon, Dennis C. Reuter, Lindsay P. Keller, M. Antonietta Barucci, Humberto Campins, Cateline Lantz, Daniella N. Dellagiustina, Ronald-Louis Ballouz, Erica R. Jawin, Harold Connolly Jr., Kevin J. Walsh, Dante Lauretta

School of Earth & Environment Faculty Scholarship

The surfaces of airless bodies such as lunar and S-type asteroids typically become spectrally redder in visible to near-infrared reflectance with longer exposures to space weathering. However, some carbonaceous asteroids instead become spectrally bluer. Space weathering experiments on carbonaceous meteorites have provided some clues as to the space weathering products that could produce spectral bluing. We applied these experimental results to our Hapke radiative transfer model, with which we modeled spectral data from the OSIRIS-REx mission in order to determine whether these space weathering products—specifically, nanophase and microphase metallic iron, troilite, and magnetite—could explain the globally blue spectrum of the …

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Distances To Galactic X-Ray Binaries With Gaia Dr2, R. M. Arnason, H. Papei, P. Barmby, A. Bahramian, M. D. Gorski Apr 2021

Distances To Galactic X-Ray Binaries With Gaia Dr2, R. M. Arnason, H. Papei, P. Barmby, A. Bahramian, M. D. Gorski

Physics and Astronomy Publications

Precise and accurate measurements of distances to Galactic X-ray binaries (XRBs) reduce uncertainties in the determination of XRB physical parameters. We have cross-matched the XRB catalogues of Liu, van Paradijs & van den Heuvel to the results of Gaia Data Release 2. We identify 86 XRBs with a Gaia candidate counterpart, of which 32 are low-mass X-ray binaries (LMXBs) and 54 are high-mass X-ray binaries (HMXBs). Distances to Gaia candidate counterparts are, on average, consistent with those measured by Hipparcos and radio parallaxes. When compared to distances measured by Gaia candidate counterparts, distances measured using Type I X-ray bursts are …

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On The Observational Difference Between The Accretion Disk-Corona Connections Among Super- And Sub-Eddington Accreting Active Galactic Nuclei, Hezhen Liu, B. Luo, W. N. Brandt, Michael S. Brotherton, Sarah C. Gallagher, Q. Ni, Ohad Shemmer, J. D. Timlin Apr 2021

On The Observational Difference Between The Accretion Disk-Corona Connections Among Super- And Sub-Eddington Accreting Active Galactic Nuclei, Hezhen Liu, B. Luo, W. N. Brandt, Michael S. Brotherton, Sarah C. Gallagher, Q. Ni, Ohad Shemmer, J. D. Timlin

Physics and Astronomy Publications

We present a systematic X-ray and multiwavelength study of a sample of 47 active galactic nuclei (AGNs) with reverberation mapping measurements. This sample includes 21 super-Eddington accreting AGNs and 26 sub-Eddington accreting AGNs. Using high-state observations with simultaneous X-ray and UV/optical measurements, we investigate whether super-Eddington accreting AGNs exhibit different accretion disk-corona connections compared to sub-Eddington accreting AGNs. We find tight correlations between the X-ray-to-UV/optical spectral slope parameter (α OX) and the monochromatic luminosity at 2500 Å (L 2500Å) for both the super- and sub-Eddington subsamples. The best-fit α OX-L 2500Å relations are consistent overall, indicating that super-Eddington accreting AGNs …

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Ast 101: Introductory Astronomy, Cuny School Of Professional Studies Apr 2021

Ast 101: Introductory Astronomy, Cuny School Of Professional Studies

Open Educational Resources

An exploration of our solar system’s creation and the planets in our solar system using the latest scientific information, recent probe data, and new discoveries in the science of extra-solar planetary astronomy. This course is based in part upon materials developed by the American Museum of Natural History and is used with permission by the School of Professional Studies for this course.

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R Coronae Borealis Star Evolution: Simulating 3d Merger Events To 1d Stellar Evolution Including Large-Scale Nucleosynthesis, Bradley Munson, Emmanouil Chatzopoulos, Juhan Frank, Geoffrey Clayton, Courtney Crawford, Pavel A. Denissenkov, Falk Herwig Apr 2021

R Coronae Borealis Star Evolution: Simulating 3d Merger Events To 1d Stellar Evolution Including Large-Scale Nucleosynthesis, Bradley Munson, Emmanouil Chatzopoulos, Juhan Frank, Geoffrey Clayton, Courtney Crawford, Pavel A. Denissenkov, Falk Herwig

Faculty Publications

R Coronae Borealis (RCB) stars are rare hydrogen-deficient carbon-rich variable supergiants thought to be the result of dynamically unstable white dwarf mergers. We attempt to model RCB stars through all the relevant timescales by simulating a merger event in Octo-tiger, a 3D adaptive mesh refinement (AMR) hydrodynamics code, and mapping the post-merger object into MESA, a 1D stellar evolution code. We then post-process the nucleosynthesis on a much larger nuclear reaction network to study the enhancement of s-process elements. We present models that match observations or previous studies in most surface abundances, isotopic ratios, early evolution, and lifetimes. We also …

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Search For The Dark Photon In B 0 → A′A′, A′ → E + E −, Μ + Μ −, And Π + Π − Decays At Belle, S. H. Park, Y. J. Kwon, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, T. Aushev, R. Ayad, V. Babu, P. Behera, J. Bennett, M. Bessner, V. Bhardwaj, B. Bhuyan, T. Bilka, J. Biswal, G. Bonvicini, A. Bozek Apr 2021

Search For The Dark Photon In B 0 → A′A′, A′ → E + E −, Μ + Μ −, And Π + Π − Decays At Belle, S. H. Park, Y. J. Kwon, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, T. Aushev, R. Ayad, V. Babu, P. Behera, J. Bennett, M. Bessner, V. Bhardwaj, B. Bhuyan, T. Bilka, J. Biswal, G. Bonvicini, A. Bozek

Faculty and Student Publications

We present a search for the dark photon A′ in the B0 → A′A′ decays, where A′ subsequently decays to e+e−, μ+μ−, and π+π−. The search is performed by analyzing 772 × 106BB¯ events collected by the Belle detector at the KEKB e+e− energy-asymmetric collider at the ϒ(4S) resonance. No signal is found in the dark photon mass range 0.01 GeV/c2 ≤ mA′ ≤ 2.62 GeV/c2, and we set upper limits of the branching fraction of B0 → A′A′ at the 90% confidence level. The products of branching fractions, ℬ(B0→A′A′)×ℬ(A′→e+e−)2 and ℬ(B0→A′A′)×ℬ(A′→μ+μ−)2, have limits of the order of 10−8 depending …

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Precise Transit And Radial-Velocity Characterization Of A Resonant Pair: The Warm Jupiter Toi-216c And Eccentric Warm Neptune Toi-216b, R. I. Dawson, C. X. Huang, R. Brahm, K. A. Collins, M. J. Hobson, A. Jordán, J. Dong, J. Korth, T. Trifonov, L. Abe, A. Agabi, I. Bruni, R. P. Butler, M. Barbieri, K. I. Collins, D. M. Conti, J. D. Crane, N. Crouzet, G. Dransfield, P. Evans, N. Espinoza, T. Gan, T. Guillot, T. Henning, J. J. Lissauer, Eric L. N. Jensen, W. M. Sainte, D. Mékarnia, G. Myers, S. Nandakumar, H. M. Relles, P. Sarkis, P. Torres, S. Shectman, F.-X. Schmider, A. Shporer, C. Stockdale, J. Teske, A. H. M. J. Triaud, S. X. Wang, C. Ziegler, G. Ricker, R. Vanderspek, D. W. Latham, S. Seager, J. Winn, J. M. Jenkins, L. G. Bouma, J. A. Burt, D. Charbonneau, A. M. Levine, S. Mcdermott, B. Mclean, M. E. Rose, A. Vanderburg, B. Wohler Apr 2021

Precise Transit And Radial-Velocity Characterization Of A Resonant Pair: The Warm Jupiter Toi-216c And Eccentric Warm Neptune Toi-216b, R. I. Dawson, C. X. Huang, R. Brahm, K. A. Collins, M. J. Hobson, A. Jordán, J. Dong, J. Korth, T. Trifonov, L. Abe, A. Agabi, I. Bruni, R. P. Butler, M. Barbieri, K. I. Collins, D. M. Conti, J. D. Crane, N. Crouzet, G. Dransfield, P. Evans, N. Espinoza, T. Gan, T. Guillot, T. Henning, J. J. Lissauer, Eric L. N. Jensen, W. M. Sainte, D. Mékarnia, G. Myers, S. Nandakumar, H. M. Relles, P. Sarkis, P. Torres, S. Shectman, F.-X. Schmider, A. Shporer, C. Stockdale, J. Teske, A. H. M. J. Triaud, S. X. Wang, C. Ziegler, G. Ricker, R. Vanderspek, D. W. Latham, S. Seager, J. Winn, J. M. Jenkins, L. G. Bouma, J. A. Burt, D. Charbonneau, A. M. Levine, S. Mcdermott, B. Mclean, M. E. Rose, A. Vanderburg, B. Wohler

Physics & Astronomy Faculty Works

TOI-216 hosts a pair of warm, large exoplanets discovered by the TESS mission. These planets were found to be in or near the 2:1 resonance, and both of them exhibit transit timing variations (TTVs). Precise characterization of the planets' masses and radii, orbital properties, and resonant behavior can test theories for the origins of planets orbiting close to their stars. Previous characterization of the system using the first six sectors of TESS data suffered from a degeneracy between planet mass and orbital eccentricity. Radial-velocity measurements using HARPS, FEROS, and the Planet Finder Spectrograph break that degeneracy, and an expanded TTV …

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Comparing Dust In Other Galaxies To Dust In Our Galaxy, Fatima Elkhatib Apr 2021

Comparing Dust In Other Galaxies To Dust In Our Galaxy, Fatima Elkhatib

Senior Theses

Interstellar dust in galaxies has a profound effect on the galaxies’ light output and apparent properties as well as on the physical processes connected to star formation. Therefore, to understand the true properties of the galaxies around us, it is important to understand the dust in those galaxies and compare it to the dust in our galaxy. To do this, we study the effects of dust on background quasars by analyzing interstellar reddening and extinction. It has been shown that many quasars look redder and dimmer than the average quasar when observing them from Earth, due to the dust in …

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A Hot Mini-Neptune In The Radius Valley Orbiting Solar Analogue Hd 110113, H. P. Osborn, D. J. Armstrong, V. Adibekyan, K. A. Collins, E. Delgado-Mena, S. B. Howell, C. Hellier, G. W. King, J. Lillo-Box, L. D. Nielsen, J. F. Otegi, N. C. Santos, C. Ziegler, D. R. Anderson, C. Briceño, C. Burke, D. Bayliss, D. Barrado, E. M. Bryant, D. J. A. Brown, S. C. C. Barros, F. Bouchy, D. A. Caldwell, D. M. Conti, R. F. Díaz, D. Dragomir, M. Deleuil, O. D. S. Demangeon, C. Dorn, T. Daylan, P. Figueira, R. Helled, S. Hoyer, J. M. Jenkins, Eric L.N. Jensen, D. W. Latham, N. Law, D. R. Louie, A. W. Mann, A. Osborn, D. L. Pollacco, D. R. Rodriguez, B. V. Rackham, G. Ricker, N. J. Scott, S. G. Sousa, S. Seager, K. G. Stassun, J. C. Smith, P. Strøm, S. Udry, J. Villaseñor, R. Vanderspek, R. West, P. J. Wheatley, J. N. Winn Apr 2021

A Hot Mini-Neptune In The Radius Valley Orbiting Solar Analogue Hd 110113, H. P. Osborn, D. J. Armstrong, V. Adibekyan, K. A. Collins, E. Delgado-Mena, S. B. Howell, C. Hellier, G. W. King, J. Lillo-Box, L. D. Nielsen, J. F. Otegi, N. C. Santos, C. Ziegler, D. R. Anderson, C. Briceño, C. Burke, D. Bayliss, D. Barrado, E. M. Bryant, D. J. A. Brown, S. C. C. Barros, F. Bouchy, D. A. Caldwell, D. M. Conti, R. F. Díaz, D. Dragomir, M. Deleuil, O. D. S. Demangeon, C. Dorn, T. Daylan, P. Figueira, R. Helled, S. Hoyer, J. M. Jenkins, Eric L.N. Jensen, D. W. Latham, N. Law, D. R. Louie, A. W. Mann, A. Osborn, D. L. Pollacco, D. R. Rodriguez, B. V. Rackham, G. Ricker, N. J. Scott, S. G. Sousa, S. Seager, K. G. Stassun, J. C. Smith, P. Strøm, S. Udry, J. Villaseñor, R. Vanderspek, R. West, P. J. Wheatley, J. N. Winn

Physics & Astronomy Faculty Works

We report the discovery of HD 110113 b (TESS object of interest-755.01), a transiting mini-Neptune exoplanet on a 2.5-d orbit around the solar-analogue HD 110113 (Teff = 5730 K). Using TESS photometry and High Accuracy Radial velocity Planet Searcher (HARPS) radial velocities gathered by the NCORES program, we find that HD 110113 b has a radius of 2.05 ± 0.12  R⊕ and a mass of 4.55 ± 0.62  M⊕. The resulting density of 2.90+0.75−0.59  g cm−3 is significantly lower than would be expected from a pure-rock world; therefore HD 110113 b must be a mini-Neptune with a significant volatile atmosphere. …

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Tic 168789840: A Sextuply Eclipsing Sextuple Star System, B. P. Powell, V. B. Kostov, S. A. Rappaport, T. Borkovits, P. Zasche, A. Tokovinin, E. Kruse, D. W. Latham, B. T. Montet, Eric L.N. Jensen, R. Jayaraman, K. A. Collins, M. Mašek, C. Hellier, P. Evans, T.-G. Tan, J. E. Schlieder, G. Torres, A. P. Smale, A. H. Friedman, T. Barclay, R. Gagliano, E. V. Quintana, T. L. Jacobs, E. A. Gilbert, M. H. Kristiansen, K. D. Colón, D. M. Lacourse, G. Olmschenk, M. Omohundro, J. D. Schnittman, H. M. Schwengeler, R. K. Barry, I. A. Terentev, P. Boyd, A. R. Schmitt, S. M. Quinn, A. Vanderburg, E. Palle, J. Armstrong, G. R. Ricker, R. Vanderspek, S. Seager, J. N. Winn, J. M. Jenkins, D. A. Caldwell, B. Wohler, B. Shiao, C. J. Burke, T. Daylan, J. Villaseñor Apr 2021

Tic 168789840: A Sextuply Eclipsing Sextuple Star System, B. P. Powell, V. B. Kostov, S. A. Rappaport, T. Borkovits, P. Zasche, A. Tokovinin, E. Kruse, D. W. Latham, B. T. Montet, Eric L.N. Jensen, R. Jayaraman, K. A. Collins, M. Mašek, C. Hellier, P. Evans, T.-G. Tan, J. E. Schlieder, G. Torres, A. P. Smale, A. H. Friedman, T. Barclay, R. Gagliano, E. V. Quintana, T. L. Jacobs, E. A. Gilbert, M. H. Kristiansen, K. D. Colón, D. M. Lacourse, G. Olmschenk, M. Omohundro, J. D. Schnittman, H. M. Schwengeler, R. K. Barry, I. A. Terentev, P. Boyd, A. R. Schmitt, S. M. Quinn, A. Vanderburg, E. Palle, J. Armstrong, G. R. Ricker, R. Vanderspek, S. Seager, J. N. Winn, J. M. Jenkins, D. A. Caldwell, B. Wohler, B. Shiao, C. J. Burke, T. Daylan, J. Villaseñor

Physics & Astronomy Faculty Works

We report the discovery of a sextuply eclipsing sextuple star system from TESS data, TIC 168789840, also known as TYC 7037-89-1, the first known sextuple system consisting of three eclipsing binaries. The target was observed in Sectors 4 and 5 during Cycle 1, with lightcurves extracted from TESS Full Frame Image data. It was also previously observed by the WASP survey and ASAS-SN. The system consists of three gravitationally bound eclipsing binaries in a hierarchical structure of an inner quadruple system with an outer binary subsystem. Follow-up observations from several different observatories were conducted as a means of determining additional …

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Tess Delivers Five New Hot Giant Planets Orbiting Bright Stars From The Full-Frame Images, J. E. Rodriguez, S. N. Quinn, G. Zhou, A. Vanderburg, L. D. Nielsen, R. A. Wittenmyer, R. Brahm, P. A. Reed, C. X. Huang, S. Vach, D. R. Ciardi, R. J. Oelkers, K. G. Stassun, C. Hellier, B. S. Gaudi, J. D. Eastman, K. A. Collins, A. Bieryla, S. Christian, D. W. Latham, I. Carleo, D. J. Wright, E. Matthews, E. J. Gonzales, C. Ziegler, C. D. Dressing, S. B. Howell, T.-G. Tan, J. Wittrock, P. Plavchan, K. K. Mcleod, D. Baker, G. Wang, D. J. Radford, R. P. Schwarz, M. Esposito, G. R. Ricker, R. K. Vanderspek, S. Seager, J. N. Winn, J. M. Jenkins, B. Addison, D. R. Anderosn, T. Barclay, T. G. Beatty, P. Berlind, F. Bouchy, M. Bowen, B. P. Bowler, C. E. Brasseur, C. Briceño, D. A. Caldwell, M. L. Calkins, S. Cartwright, P. Chaturvedi, G. Chaverot, S. Chimaladinne, J. L. Christiansen, K. I. Collins, I. J. M. Crossfield, K. Eastridge, N. Espinoza, G. A. Esquerdo, D. L. Felix, T. Fenske, W. Fong, T. Gan, S. Giacalone, H. Gill, L. Gordon, A. Granados, N. Grieves, E. W. Guenther, N. Guerrero, T. Henning, C. E. Henze, K. Hesse, M. J. Hobson, J. Horner, D. J. James, Eric L. N. Jensen, M. Jimenez, A. Jordán, S. R. Kane, J. Kielkopf, K. Kim, R. B. Kuhn, N. Latouf, N. M. Law, A. M. Levine, M. B. Lund, A. W. Mann, S. Mao, R. A. Matson, M. W. Mengel, J. Mink, P. Newman, T. O’Dwyer, J. Okumura, E. Palle, J. Pepper, E. V. Quintana, P. Sarkis, A. B. Savel, J. E. Schlieder, C. Schnaible, A. Shporer, R. Sefako, J. V. Seidel, R. J. Siverd, B. Skinner, M. Stalport, D. J. Stevens, C. Stibbards, C. G. Tinney, R. G. West, D. A. Yahalomi, H. Zhang Apr 2021

Tess Delivers Five New Hot Giant Planets Orbiting Bright Stars From The Full-Frame Images, J. E. Rodriguez, S. N. Quinn, G. Zhou, A. Vanderburg, L. D. Nielsen, R. A. Wittenmyer, R. Brahm, P. A. Reed, C. X. Huang, S. Vach, D. R. Ciardi, R. J. Oelkers, K. G. Stassun, C. Hellier, B. S. Gaudi, J. D. Eastman, K. A. Collins, A. Bieryla, S. Christian, D. W. Latham, I. Carleo, D. J. Wright, E. Matthews, E. J. Gonzales, C. Ziegler, C. D. Dressing, S. B. Howell, T.-G. Tan, J. Wittrock, P. Plavchan, K. K. Mcleod, D. Baker, G. Wang, D. J. Radford, R. P. Schwarz, M. Esposito, G. R. Ricker, R. K. Vanderspek, S. Seager, J. N. Winn, J. M. Jenkins, B. Addison, D. R. Anderosn, T. Barclay, T. G. Beatty, P. Berlind, F. Bouchy, M. Bowen, B. P. Bowler, C. E. Brasseur, C. Briceño, D. A. Caldwell, M. L. Calkins, S. Cartwright, P. Chaturvedi, G. Chaverot, S. Chimaladinne, J. L. Christiansen, K. I. Collins, I. J. M. Crossfield, K. Eastridge, N. Espinoza, G. A. Esquerdo, D. L. Felix, T. Fenske, W. Fong, T. Gan, S. Giacalone, H. Gill, L. Gordon, A. Granados, N. Grieves, E. W. Guenther, N. Guerrero, T. Henning, C. E. Henze, K. Hesse, M. J. Hobson, J. Horner, D. J. James, Eric L. N. Jensen, M. Jimenez, A. Jordán, S. R. Kane, J. Kielkopf, K. Kim, R. B. Kuhn, N. Latouf, N. M. Law, A. M. Levine, M. B. Lund, A. W. Mann, S. Mao, R. A. Matson, M. W. Mengel, J. Mink, P. Newman, T. O’Dwyer, J. Okumura, E. Palle, J. Pepper, E. V. Quintana, P. Sarkis, A. B. Savel, J. E. Schlieder, C. Schnaible, A. Shporer, R. Sefako, J. V. Seidel, R. J. Siverd, B. Skinner, M. Stalport, D. J. Stevens, C. Stibbards, C. G. Tinney, R. G. West, D. A. Yahalomi, H. Zhang

Physics & Astronomy Faculty Works

We present the discovery and characterization of five hot and warm Jupiters—TOI-628 b (TIC 281408474; HD 288842), TOI-640 b (TIC 147977348), TOI-1333 b (TIC 395171208, BD+47 3521A), TOI-1478 b (TIC 409794137), and TOI-1601 b (TIC 139375960)—based on data from NASA's Transiting Exoplanet Survey Satellite (TESS). The five planets were identified from the full-frame images and were confirmed through a series of photometric and spectroscopic follow-up observations by the TESS Follow-up Observing Program Working Group. The planets are all Jovian size (RP = 1.01–1.77 RJ) and have masses that range from 0.85 to 6.33 MJ. The host stars of these systems …

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A Neural Network Approach To Identifying Ysos And Exploring Solar Neighborhood Star-Forming History, Aidan Mcbride, Ryan Lingg, Marina Kounkel, Kevin Covey, Brian Hutchinson Apr 2021

A Neural Network Approach To Identifying Ysos And Exploring Solar Neighborhood Star-Forming History, Aidan Mcbride, Ryan Lingg, Marina Kounkel, Kevin Covey, Brian Hutchinson

WWU Honors College Senior Projects

Stellar ages can act as a marker of birth cluster membership for young stellar objects (YSOs), which allows for an improved understanding of the history of star formation in the solar neighborhood. However, the ages of YSOs have historically been difficult to predict on a large scale. Here, we develop a system of convolution neural network models to differentiate between YSOs and their more-evolved counterparts and predict YSO ages using Gaia and 2MASS photometry. The full model and resulting catalog recovers the properties of well-studied young stellar populations to a distance of five kiloparsecs, with significantly higher sensitivity within one …

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Gwtc-2: Compact Binary Coalescences Observed By Ligo And Virgo During The First Half Of The Third Observing Run, Ligo Scientific Collaboration, Virgo Collaboration, Tiffany Z. Summerscales Apr 2021

Gwtc-2: Compact Binary Coalescences Observed By Ligo And Virgo During The First Half Of The Third Observing Run, Ligo Scientific Collaboration, Virgo Collaboration, Tiffany Z. Summerscales

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 …

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A New Method For Estimating The Physical Characteristics Of Martian Dust Devils, Shelly Cahoon Mann Apr 2021

A New Method For Estimating The Physical Characteristics Of Martian Dust Devils, Shelly Cahoon Mann

Mechanical & Aerospace Engineering Theses & Dissertations

Critical to the future exploration of Mars is having a detailed understanding of the atmospheric environment and its potential dangers. The dust devil is one of these potential dangers. The transport of dust through saltation is believed to be the driving mechanism responsible for Martian weather patterns. The two primary mechanisms for dust transport are dust storms and dust devils. Dust devils on Mars are a frequent occurrence with one in five so called giant dust devils being large enough to leave scars on the surface that are visible from space. Due to the thin atmosphere, winds of 60 mph …

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Galaxy And Mass Assembly (Gama): The Inferred Mass–Metallicity Relation From Z = 0 To 3.5 Via Forensic Sed Fitting, Sabine Bellstedt, Aaron S G Robotham, Simon P. Driver, Jessica E. Thorne, Luke J M Davies, Benne Holwerda, Andrew M. Hopkins, Maritza A. Lara-Lopez, Ángel R. López-Sánchez, Steven Phillipps Mar 2021

Galaxy And Mass Assembly (Gama): The Inferred Mass–Metallicity Relation From Z = 0 To 3.5 Via Forensic Sed Fitting, Sabine Bellstedt, Aaron S G Robotham, Simon P. Driver, Jessica E. Thorne, Luke J M Davies, Benne Holwerda, Andrew M. Hopkins, Maritza A. Lara-Lopez, Ángel R. López-Sánchez, Steven Phillipps

Faculty Scholarship

We analyse the metallicity histories of ∼4500 galaxies from the GAMA survey at z < 0.06 modelled by the SED-fitting code PROSPECT using an evolving metallicity implementation. These metallicity histories, in combination with the associated star formation histories, allow us to analyse the inferred gas-phase mass–metallicity relation. Furthermore, we extract the mass– metallicity relation at a sequence of epochs in cosmic history, to track the evolving mass–metallicity relation with time. Through comparison with observations of gas-phase metallicity over a large range of redshifts, we show that, remarkably, our forensic SED analysis has produced an evolving mass–metallicity relationship that is consistent with observations at all epochs. We additionally analyse the three-dimensional mass–metallicity–SFR space, showing that galaxies occupy a clearly defined plane. This plane is shown to be subtly evolving, displaying an increased tilt with time caused by general enrichment, and also the slowing down of star formation with cosmic time. This evolution is most apparent at lookback times greater than 7 Gyr. The trends in metallicity recovered in this work highlight that the evolving metallicity implementation used within the SED-fitting code PROSPECT produces reasonable metallicity results over the history of a galaxy. This is expected to provide a significant improvement to the accuracy of the SED-fitting outputs.

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Determining The Origins Of Helix Glitches In Ligo’S H1 Detector, Kara Shepard Mar 2021

Determining The Origins Of Helix Glitches In Ligo’S H1 Detector, Kara Shepard

Honors Scholars & Undergraduate Research Poster Symposium Programs

The LIGO detectors are ultra-sensitive, making them susceptible to glitches from the noise that can block gravitational wave signals. In order to reduce the number of glitches that occur in the detector, the cause of the glitches must be found. I am researching the Helix glitch to try and determine its origin. This is accomplished by studying the times at which the glitch occurred in the detector and then looking for factors that may have caused a glitch to happen around the same time, to see if there are any correlations.

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Light And Truth: Measuring Unseen Harm In Individuals And Communities, Hannah Pfost Mar 2021

Light And Truth: Measuring Unseen Harm In Individuals And Communities, Hannah Pfost

Undergraduate Honors Theses

While the fields of physics and international development may seem disparate, the insights gained from studying each one of them can improve understanding of the other. Here, I demonstrate that concept as applied to computational optics and historical memory. Thus, the purpose of this project is threefold: (1) to computationally model light transport through tissue, and use that model to inform choices about a physical system; (2) to determine the types of historical memory recommended in the final reports of truth commissions; and (3) to give evidence for the usefulness of human-centered design in both areas. To model light transport, …

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Primordial Power Spectrum From A Matter-Ekpyrotic Bounce Scenario In Loop Quantum Cosmology, Bao-Fei Li, Sahil Saini, Parampreet Singh Mar 2021

Primordial Power Spectrum From A Matter-Ekpyrotic Bounce Scenario In Loop Quantum Cosmology, Bao-Fei Li, Sahil Saini, Parampreet Singh

Faculty Publications

A union of matter bounce and ekpyrotic scenarios is often studied in an attempt to combine the most promising features of these two models. Since nonperturbative quantum geometric effects in loop quantum cosmology (LQC) result in natural bouncing scenarios without any violation of energy conditions or fine tuning, an investigation of matter-ekpyrotic bounce scenario is interesting to explore in this quantum gravitational setting. In this work, we explore this unified phenomenological model for a spatially flat Friedmann-Lemaistre-Robertson-Walker (FLRW) universe in LQC filled with dust and a scalar field in an ekpyrotic scenario like negative potential. Background dynamics and the power …

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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 and Astronomy Faculty Publications and Presentations

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 and Astronomy Faculty Publications and Presentations

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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