Astrophysics and Astronomy Commons^™

New Physics In The Age Of Precision Cosmology, Vivian I. Sabla

Dartmouth College Ph.D Dissertations

The Lambda-cold dark matter (LCDM) model has become the standard model of cosmology because of its ability to reproduce a vast array of cosmological observations, from the earliest moments of our Universe, to the current period of accelerated expansion, which it does with great accuracy. However, the success of this model only distracts from its inherent flaws and ambiguities. LCDM is purely phenomenological, providing no physical explanation for the nature of dark matter, responsible for the formation and evolution of large-scale structure, and giving an inconclusive explanation for dark energy, which drives the current period of accelerated expansion.

Furthermore, cracks …

Applying Bioactive Glass Beads For Long-Term Drug Delivery, Marie O. Sykes, Rashi Sharma

Physics and Astronomy Presentations

Bioactive glass beads have been used to distribute medicine over extended periods of time in limited uses. They can be engineered to have a porous and hollow structure, and using Mo-Sci's OL-GL 1756b (1756b), the fundamental notion of dosage distribution can be tested in preparation to design the optimal glass for medicine distribution. A few key factors in this is how long does it take the liquid to release from the beads, how do the beads decay, and how well the glass can bond to human tissue. This research demonstrates the capacities of the 1756b type as a promising start …

Paul Feder Observatory Upgrades And Exoplanet And Variable Star Data, Mara Derung, Tanner Weyer, Emily Watson

Student Academic Conference

Before the upgrade to the dome and telescope, much of the work to use the telescope was done manually. One had to drive an hour round trip to the observatory at dusk and dawn to ensure that the telescope started up and shutdown properly. Proper startup included manually opening the lower dome flap via hand crank and briefly plugging in the top part of the dome to raise the upper slit. Shutting down the telescope during the summer required a person to be at the telescope by 5:00AM, before sunrise to make sure that the dome closed before the sun …

Identifying Gravity Waves Launched By The Hunga Tonga–Hunga Ha’Apai Volcanic Eruption In Mesosphere/Lower-Thermosphere Winds Derived From Condor And The Nordic Meteor Radar Cluster, Gunter Stober, Alan Liu, Alexander Kozlovsky, Zishun Qiao, Witali Krochin, Guochun Shi, Johan Kero, Et Al.

Publications

The Hunga Tonga–Hunga Ha'apai volcano eruption was a unique event that caused many atmospheric phenomena around the globe. In this study, we investigate the atmospheric gravity waves in the mesosphere/lower thermosphere (MLT) launched by the volcanic explosion in the Pacific, leveraging multistatic meteor radar observations from the Chilean Observation Network De Meteor Radars (CONDOR) and the Nordic Meteor Radar Cluster in Fennoscandia. MLT winds are computed using a recently developed 3DVAR+DIV algorithm. We found eastward- and westward-traveling gravity waves in the CONDOR zonal and meridional wind measurements, which arrived 12 and 48 h after the eruption, and we found one …

Lesson Plans In Astronomy, Ecology And Biology, Admin Stem For Success

STEM for Success Showcase

This document contains various lesson plan ideas for concepts within the fields of biology, ecology, astronomy, and geology.

Information Horizon Of Solar Active Regions, Jay R. Johnson, Simon Wing, Carson O'Ffill, Bishwa Neupane

Faculty Publications

Information theory is used to characterize the solar active region periodicities and memories from the Carrington map images 1974–2021. The active regions typically evolve and move from one map to the next. In order to track these active region structures in sequences of images, an innovative method based on information theory is developed. Image entropy provides a measure of the organization of structures in the images. The entropy can also be used as a filter to identify structures and partition the active regions, which are then registered for each image. The partitions are used to compute the mutual information and …

Non-Hermitian Edge Burst Without Skin Localization, Cem Yuce, Hamidreza Ramezani

Physics & Astronomy Faculty Publications

In a class of non-Hermitian quantum walk in lossy lattices with open boundary conditions, an unexpected peak in the distribution of the decay probabilities appears at the edge, referred to as an edge burst. It is proposed that the edge burst originates jointly from the non-Hermitian skin effect (NHSE) and the imaginary gaplessness of the spectrum [W.-T. Xue et al., Phys. Rev. Lett. 128, 120401 (2022)]. Using a particular one-dimensional lossy lattice with a nonuniform loss rate, we show that the edge burst can occur even in the absence of skin localizations. Furthermore, we discuss that the edge …

Membership Probabilities Of White Dwarfs In Open Star Clusters, Sarah Phillips

Honors Theses

This thesis explores the relationship between astronomical position data and star cluster membership. Our research project focuses on the mathematical probability of cluster membership for white dwarf stars (WDs), specifically membership candidates within the open cluster Messier 35. Through Gaussian analysis of proper motion data, we examine the membership probability of each candidate. Establishing cluster membership has broad applications and can allow further determination of a star’s characteristics including stellar age and evolution. Of particular interest are two WD member candidates for Messier 35: LAWDS 4, a DB WD with a helium-dominated atmosphere as opposed to the more common hydrogen-dominated …

Cold Gas Disks In Main-Sequence Galaxies At Cosmic Noon: Low Turbulence, Flat Rotation Curves, And Disk-Halo Degeneracy, Stacy S. Mcgaugh

Faculty Scholarship

We study the dynamics of cold molecular gas in two main-sequence galaxies at cosmic noon (zC-488879 at z ≃ 1.47 and zC-400569 at z ≃ 2.24) using new high-resolution ALMA observations of multiple 12CO transitions. For zC-400569 we also reanalyze high-quality Hα data from the SINS/zC-SINF survey. We find that (1) both galaxies have regularly rotating CO disks and their rotation curves are flat out to ∼8 kpc contrary to previous results pointing to outer declines in the rotation speed Vrot; (2) the intrinsic velocity dispersions are low (σCO ≲ 15 km s-1 for CO and σHα ≲ 37 km …

Wallaby Pre-Pilot Survey: Radio Continuum Properties Of The Eridanus Supergroup, J. A. Grundy, O. I. Wong, K. Lee-Waddell, N. Seymour, B. -Q. For, C. Murugeshan, B. S. Koribalski, Juan P. Madrid, J. Rhee, T. Westmeier

Physics & Astronomy Faculty Publications

We present the highest resolution and sensitivity ∼ 1.4 GHz continuum observations of the Eridanus supergroup obtained as a part of the Widefield Australian Square Kilometer Array Pathfinder (ASKAP) L-band Legacy All-sky Blind surveY (WALLABY) pre-pilot observations using the ASKAP. We detect 9461 sources at 1.37 GHz down to a flux density limit of ∼ 0.1 mJy at 6.1′′×7.9′′ resolution with a median root mean square of 0.05 mJy beam −1 . We find that the flux scale is accurate to within 5 % (compared to NVSS at 1.4 GHz). We then determine the global properties of eight Eridanus supergroup …

Analog Cosmology And Superfluidity In Atomic Gases And Electronic Materials, Anshuman Bhardwaj

LSU Doctoral Dissertations

We present a study of analog cosmological models in Bose-Einstein condensates (BEC) and in graphene, and superfluidity in a box-shaped traps. We start by examining the dynamics of a Bose-Einstein condensate (BEC) trapped inside an expanding toroid that can realize an analog inflationary universe. The expanding condensate forces phonons to undergo redshift and damping due to quantum pressure, owing to the thinness of the ring. We predict that such expanding BECs can exhibit spontaneous phonon creation from the vacuum state and show how it would manifest in the atom density and density correlations and discuss connections with the inflationary theory. …

Phys 142h

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 442/842

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 231

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 422/822

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 813

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 914

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 928

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 221 Lab

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 222 Lab

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 213

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 451/851

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 142 Lab

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 223 Lab

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 211

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 916

Department of Physics and Astronomy: Syllabi

No abstract provided.

Toi-836: A Super-Earth And Mini-Neptune Transiting A Nearby K-Dwarf, F. Hawthorn, D. Bayliss, T. G. Wilson, A. Bonfanti, V. Adibekyan, Y. Alibert, S. G. Sousa, K. A. Collins, E. M. Bryant, A. Osborn, D. J. Armstrong, L. Abe, J. S. Acton, B. C. Addison, K. Agabi, R. Alonso, D. R. Alves, G. Anglada-Escudé, T. Bárczy, T. Barclay, D. Barrado, S. C. C. Barros, W. Baumjohann, P. Bendjoya, W. Benz, A. Bieryla, X. Bonfils, F. Bouchy, A. Brandeker, C. Broeg, D. J. A. Brown, M. R. Burleigh, M. Buttu, J. Cabrera, D. A. Caldwell, S. L. Casewell, D. Charbonneau, S. Charnoz, R. Cloutier, A. Collier Cameron, K. I. Collins, D. M. Conti, N. Crouzet, S. Czismadia, M. B. Davies, M. Deleuil, E. Delgado-Mena, L. Delrez, O. D. S. Demangeon, B.-O. Demoray, G. Dransfield, X. Dumusque, J. A. Egger, D. Ehrenreich, P. Eigmüller, A. Erickson, Z. Essack, A. Fortier, L. Fossati, M. Fridlund, M. N. Günther, M. Güdel, D. Gandolfi, H. Gillard, M. Gillon, C. Gnilka, M. R. Goad, R. F. Goeke, T. Guillot, A. Hadjigeorghiou, C. Hellier, B. A. Henderson, K. Heng, M. J. Hooton, K. Horne, S. B. Howell, S. Hoyer, J. M. Irwin, J. S. Jenkins, J. M. Jenkins, Eric L.N. Jensen, S. R. Kane, A. Kendall, J. F. Kielkopf, L. L. Kiss, G. Lacedelli, J. Laskar, D. W. Latham, A. Lecavalier Des Etangs, A. Leleu, M. Lendl, J. Lillo-Box, C. Lovis, D. Mékarnia, B. Massey, T. Masters, P. F. L. Maxted, V. Nascimbeni, L. D. Nielsen, S. M. O'Brien, G. Olofsson, H. P. Osborn, I. Pagano, E. Pallé, C. M. Persson, G. Piotto, P. Plavchan, D. Pollacco, D. Queloz, R. Ragazzoni, H. Rauer, I. Ribas, G. Ricker, D. Ségransan, S. Salmon, A. Santerne, N. C. Santos, G. Scandariato, F.-X. Schmider, R. P. Schwarz, S. Seager, A. Shporer, A. E. Simon, A. M. S. Smith, G. Srdoc, M. Steller, O. Suarez, G. M. Szabó, J. Teske, N. Thomas, R. H. Tilbrook, A. H. M. J. Triaud, S. Udry, V. Van Grootel, N. Walton, S. X. Wang, P. J. Wheatley, J. N. Winn, R. A. Wittenmyer, H. Zhang

Physics & Astronomy Faculty Works

We present the discovery of two exoplanets transiting TOI-836 (TIC 440887364) using data from TESS Sector 11 and Sector 38. TOI-836 is a bright (T = 8.5 mag), high proper motion (∼200 mas yr⁻¹), low metallicity ([Fe/H]≈−0.28) K-dwarf with a mass of 0.68 ± 0.05 M_⊙ and a radius of 0.67 ± 0.01 R⊙. We obtain photometric follow-up observations with a variety of facilities, and we use these data sets to determine that the inner planet, TOI-836 b, is a 1.70 ± 0.07 R_⊕ super-Earth in a 3.82-d orbit, placing it directly within the so-called …

Design Of A Mini Leo Gnss Constellation And A Custom Gnss Signal Simulator Development, Mohamed Mohamed Yaser

Theses

This thesis is concerned with Low Earth Orbit (LEO) Global Navigation Satellite Systems (GNSS) constellations and signals, and how can they provide rapid Positioning, Navigation, and Timing (PNT) services for the emerging technologies. The first objective of this thesis is to perform a simulation of a new mini-LEO GNSS constellation at 1000 km and assess its performance in different scenarios. The second objective is to design a signal simulator for two signals that are propriety of the Global Navigation Satellite Augmentation Systems (GNSSaS), which are the BOC(2,2) and ATLBOC(7.5, BOC(2,2)) modulation schemes. To simulate the mini-LEO GNSS constellation, two software …

Sporadic Spin-Orbit Variations In Compact Multiplanet Systems And Their Influence On Exoplanet Climate, Howard Chen, Gongjie Li, Adiv Paradise, Ravi K. Kopparapu

Aerospace, Physics, and Space Science Faculty Publications

Climate modeling has shown that tidally influenced terrestrial exoplanets, particularly those orbiting M-dwarfs, have unique atmospheric dynamics and surface conditions that may enhance their likelihood to host viable habitats. However, sporadic libration and rotation induced by planetary interactions, such as those due to mean motion resonances (MMR) in compact planetary systems, may destabilize attendant exoplanets away from synchronized states (1:1 spin-orbit ratios). Here, we use a three-dimensional N-rigid-body integrator and an intermediately complex general circulation model to simulate the evolving climates of TRAPPIST-1 e and f with different orbitaland spin-evolution pathways. Planet f scenarios perturbed by MMR effects with chaotic …

Evaluating Neutron Star Binding Energies Using Rotating Accreting Models, Nathan Moore

Honors Theses

Neutron star binding energy increases due to accreting matter from neighboring astronomical bodies, and decreases due to the star spinning up, increasing its angular velocity. We present a novel set of models that account for both increasing angular velocity and accreting matter to track a neutron star’s evolution. We arrive at these models through studying and reconfiguring computational investigations from the past, particularly a code which generates a model for a given fixed baryon mass and angular velocity and another that takes it from one baryon mass and angular velocity to the next one through accretion, to obtain a full …