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2023

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Articles 241 - 270 of 362

Full-Text Articles in Astrophysics and Astronomy

Jwst’S Pearls: Dust Attenuation And Gravitational Lensing In The Backlit-Galaxy System Vv 191, William C. Keel, Rogier A. Windhorst, Rolf A. Jansen, Seth H. Cohen, Jake Summers, Benne Holwerda, Sarah T. Bradford, Clayton D. Robertson, Giovanni Ferrami, Stuart Wyithe, Haojing Yan, Christopher J. Conselice, Simon P. Driver, Aaron Robotham, Norman A. Grogin, Christopher N. A. Willmer, Anton M. Koekemoer, Brenda L. Frye, Nimish P. Hathi, Russell E. Ryan Jr., Nor Pirzkal, Madeline A. Marshall, Dan Coe, Jose M. Diego, Thomas J. Broadhurst, Michael J. Rutkowski, Lifan Wang, S. P. Willner, Andreea Petric, Cheng Cheng, Adi Zitrin Apr 2023

Jwst’S Pearls: Dust Attenuation And Gravitational Lensing In The Backlit-Galaxy System Vv 191, William C. Keel, Rogier A. Windhorst, Rolf A. Jansen, Seth H. Cohen, Jake Summers, Benne Holwerda, Sarah T. Bradford, Clayton D. Robertson, Giovanni Ferrami, Stuart Wyithe, Haojing Yan, Christopher J. Conselice, Simon P. Driver, Aaron Robotham, Norman A. Grogin, Christopher N. A. Willmer, Anton M. Koekemoer, Brenda L. Frye, Nimish P. Hathi, Russell E. Ryan Jr., Nor Pirzkal, Madeline A. Marshall, Dan Coe, Jose M. Diego, Thomas J. Broadhurst, Michael J. Rutkowski, Lifan Wang, S. P. Willner, Andreea Petric, Cheng Cheng, Adi Zitrin

Faculty and Staff Scholarship

We present the first JWST observations of the z = 4.11 luminous radio galaxy TN J1338–1942, obtained as part of the ‘Prime Extragalactic Areas for Reionization and Lensing Science’ (‘PEARLS’) project. Our NIRCam observations, designed to probe the key rest-frame optical continuum and emission line features at this redshift, enable resolved spectral energy distribution modelling that incorporates both a range of stellar population assumptions and radiative shock models. With an estimated stellar mass of log10(M/M⊙) ∼ 10.9, TN J1338–1942 is confirmed to be one of the most massive galaxies known at this epoch. Our observations also reveal extremely high equivalent-width …

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Design Of A Mini Leo Gnss Constellation And A Custom Gnss Signal Simulator Development, Mohamed Mohamed Yaser Apr 2023

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 …

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The Extremes Of Galaxy Formation & Evolution, Kelly E. Whalen Apr 2023

The Extremes Of Galaxy Formation & Evolution, Kelly E. Whalen

Dartmouth College Ph.D Dissertations

Galaxy populations are shaped by the physical processes that regulate their star formation and central black hole growth throughout cosmic time. The primary aim of this thesis is to understand how these processes occur and how they shape evolution in some of the most extreme galaxies in the Universe including quasars, compact starbursts, and ultra-diffuse dwarfs. Gas-rich major mergers funnel large amounts of gas towards the nucleus, triggering rapid AGN accretion and compact star formation. In this work, I study powerful quasars and extreme, massive, compact starburst galaxies within the context of merger-driven galaxy evolution scenarios. One aim of this …

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Evaluating Neutron Star Binding Energies Using Rotating Accreting Models, Nathan Moore Apr 2023

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 …

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Euler And Venus' Suspicious Moon, Michael P. Saclolo Mar 2023

Euler And Venus' Suspicious Moon, Michael P. Saclolo

Euleriana

This is a brief note on Leonhard Euler's published German translation from the French of two memoirs read by Armand Henri Baudouin de Guémadeuc to the Paris Academy of Sciences in 1761 and published the same year. The memoirs report on observations made of the planet Venus, performed in Limoges, France by Jacques Montaigne, where he claimed to have detected a moon orbiting the Morning and Evening Star.

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Population Of Merging Compact Binaries Inferred Using Gravitational Waves Through Gwtc-3, R. Abbott, T. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wen Hui Wang Mar 2023

Population Of Merging Compact Binaries Inferred Using Gravitational Waves Through Gwtc-3, R. Abbott, T. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wen Hui Wang

Physics & Astronomy Faculty Publications

We report on the population properties of compact binary mergers inferred from gravitational-wave observations of these systems during the first three LIGO-Virgo observing runs. The Gravitational-Wave Transient Catalog 3 (GWTC-3) contains signals consistent with three classes of binary mergers: binary black hole, binary neutron star, and neutron star–black hole mergers. We infer the binary neutron star merger rate to be between 10 and 1700  Gpc−3 yr−1 and the neutron star–black hole merger rate to be between 7.8 and 140  Gpc−3 yr−1, assuming a constant rate density in the comoving frame and taking the union of 90% credible intervals for methods …

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Transport Effects In Non-Hermitian Nonreciprocal Systems: General Approach, Hamed Ghaemi-Dizicheh Mar 2023

Transport Effects In Non-Hermitian Nonreciprocal Systems: General Approach, Hamed Ghaemi-Dizicheh

Physics & Astronomy Faculty Publications

In this paper, we present a unifying analytical framework for identifying conditions for transport effects such as reflectionless and transparent transport, lasing, and coherent perfect absorption in non-Hermitian nonreciprocal systems using a generalized transfer matrix method. This provides a universal approach to studying the transport of tight-binding platforms, including higher-dimensional models and those with an internal degree of freedom going beyond the previously studied case of one-dimensional chains with nearest-neighbor couplings. For a specific class of tight-binding models, the relevant transport conditions and their signatures of non-Hermitian, nonreciprocal, and topological behavior are analytically tractable from a general perspective. We investigate …

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Measurement Of The Double-Differential Muon-Neutrino Charged-Current Inclusive Cross Section In The Nova Near Detector, M. A. Acero, P. Adamson, L. Aliaga, N. Anfimov, A. Antoshkin, E. Arrieta-Diaz, L. Asquith, A. Aurisano, A. Back, M. Baird, N. Balashov, P. Baldi, B. A. Bambah, S. Bashar, K. Bays, B. Behera, R. Bernstein, V. Bhatnagar, D. Bhattarai, B. Bhuyan, Roberto Petti, Et. Al. Mar 2023

Measurement Of The Double-Differential Muon-Neutrino Charged-Current Inclusive Cross Section In The Nova Near Detector, M. A. Acero, P. Adamson, L. Aliaga, N. Anfimov, A. Antoshkin, E. Arrieta-Diaz, L. Asquith, A. Aurisano, A. Back, M. Baird, N. Balashov, P. Baldi, B. A. Bambah, S. Bashar, K. Bays, B. Behera, R. Bernstein, V. Bhatnagar, D. Bhattarai, B. Bhuyan, Roberto Petti, Et. Al.

Faculty Publications

We report cross-section measurements of the final-state muon kinematics for νμ charged-current interactions in the NOvA near detector using an accumulated 8.09×1020 protons on target in the NuMI beam. We present the results as a double-differential cross section in the observed outgoing muon energy and angle, as well as single-differential cross sections in the derived neutrino energy, Eν, and square of the four-momentum transfer, Q2. We compare the results to inclusive cross-section predictions from various neutrino event generators via χ2 calculations using a covariance matrix that accounts for bin-to-bin correlations of systematic uncertainties. …

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Off-Shell Effects In Bound Nucleons And Parton Distributions From 1H, 2H, 3H, And 3He Data, S. I. Alekhin, S. A. Kulagin, Roberto Petti Mar 2023

Off-Shell Effects In Bound Nucleons And Parton Distributions From 1H, 2H, 3H, And 3He Data, S. I. Alekhin, S. A. Kulagin, Roberto Petti

Faculty Publications

We report the results of a new global QCD analysis including deep-inelastic scattering data off 1H, 2H, 3H, and 3He targets. Nuclear corrections are treated in terms of a nuclear convolution approach with off-shell bound nucleons. The off-shell (OS) corrections responsible for the modification of the structure functions (SFs) of bound nucleons are constrained in a global fit along with the proton parton distribution functions (PDFs) and the higher-twist (HT) terms. We investigate the proton-neutron difference for the OS correction and discuss our predictions for the SF ratio F n 2 / F p 2 and …

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Estimating The Oblateness Of Dark Matter Halos Using Neutral Hydrogen Velocity Dispersion, Stacy S. Mcgaugh Mar 2023

Estimating The Oblateness Of Dark Matter Halos Using Neutral Hydrogen Velocity Dispersion, Stacy S. Mcgaugh

Faculty Scholarship

We derive the oblateness parameter q of the dark matter halo of a sample of gas-rich, face-on disk galaxies. We have assumed that the halos are triaxial in shape but their axes in the disk plane (a and b) are equal, so that q = c/a measures the halo flattening. We have used the H i velocity dispersion, derived from the stacked H i emission lines and the disk surface density, determined from the H i flux distribution, to determine the disk potential and the halo shape at the R 25 and 1.5R 25 radii. We have applied our model …

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The Quantitative Microanalysis Explorer: Introducing Web-Based Visualization For Optical, Electron, And Quantitative X-Ray Maps For Studying Lunar Samples, Angelina Minocha Mar 2023

The Quantitative Microanalysis Explorer: Introducing Web-Based Visualization For Optical, Electron, And Quantitative X-Ray Maps For Studying Lunar Samples, Angelina Minocha

Senior Honors Papers / Undergraduate Theses

Modern sample imaging techniques produce data in the form of large mosaics, wherein every pixel contains valuable mineralogical information. These heavy data files are challenging for most computers to load and process, furthermore access to lunar and other extraterrestrial samples is limited. We developed the QME Tool to display optical, electron, and quantitative x-ray maps in conjunction with one another to overcome these challenges and advance mineralogy data presentation and analysis. The images and quantitative data was collected using specialized techniques, followed by an extensive image co-registration process. The interface was developed using OpenSeadragon, “An open-source, web-based viewer for high-resolution …

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Stellar Binaries And Post-Merger Evolution: A Framework For Stellar Evolution And Nucleosynthesis In R Coronae Borealis Stars, Bradley Munson Mar 2023

Stellar Binaries And Post-Merger Evolution: A Framework For Stellar Evolution And Nucleosynthesis In R Coronae Borealis Stars, Bradley Munson

LSU Doctoral Dissertations

We have developed a framework for simulating binary stars through all three relevant
timescales: the dynamical merger, thermal, and nuclear evolution. The framework begins by simulating a dynamical merger in a 3-dimensional hydrodynamics adaptive mesh refinement code, Octo-Tiger, and performing a spherical averaging calculation to map the post-merger remnant into the 1-dimensional stellar evolution code, MESA. In this work, we primarily utilize this framework for simulating double white dwarf mergers, which are believed to be the progenitor to R Coronae Borealis (RCB) stars. We evolve the post-merger in MESA and compare the computed surface abundances to those observed …

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Powerful Radio Sources In The Southern Sky. I. Optical Identifications, Francesco Massaro, S. V. White, A. García-Pérez, A. Jimenez-Gallardo, A. Capetti, C. C. Cheung, W. R. Forman, C. Mazzucchelli, A. Paggi, Juan P. Madrid Mar 2023

Powerful Radio Sources In The Southern Sky. I. Optical Identifications, Francesco Massaro, S. V. White, A. García-Pérez, A. Jimenez-Gallardo, A. Capetti, C. C. Cheung, W. R. Forman, C. Mazzucchelli, A. Paggi, Juan P. Madrid

Physics & Astronomy Faculty Publications

Since the early sixties, our view of radio galaxies and quasars has been drastically shaped by discoveries made thanks to observations of radio sources listed in the Third Cambridge Catalog and its revised version (3CR). However, the largest fraction of data collected to date on 3CR sources was performed with relatively old instruments, rarely repeated and/or updated. Importantly, the 3CR contains only objects located in the Northern Hemisphere, thus having limited access to new and innovative astronomical facilities. To mitigate these limitations, we present a new catalog of powerful radio sources visible from the Southern Hemisphere, extracted from the GLEAM …

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The Puzzle Of The Formation Of T8 Dwarf Ross 458c, Josefine Gaarn, Ben Burningham, Jacqueline K. Faherty, Channon Visscher, Mark S. Marley, Eileen C. Gonzales, Emily Calamari, Daniella Bardalez Gagliuffi, Roxana Lupu, Richard Freedman Mar 2023

The Puzzle Of The Formation Of T8 Dwarf Ross 458c, Josefine Gaarn, Ben Burningham, Jacqueline K. Faherty, Channon Visscher, Mark S. Marley, Eileen C. Gonzales, Emily Calamari, Daniella Bardalez Gagliuffi, Roxana Lupu, Richard Freedman

Faculty Work Comprehensive List

At the lowest masses, the distinction between brown dwarfs and giant exoplanets is often blurred and literature classifications rarely reflect the deuterium burning boundary. Atmospheric characterization may reveal the extent to which planetary formation pathways contribute to the population of very low mass brown dwarfs, by revealing whether their abundance distributions differ from those of the local field population or, in the case of companions, their primary stars. The T8 dwarf Ross 458c is a possible planetary-mass companion to a pair of M dwarfs, and previous work suggests that it is cloudy. We here present the results of the retrieval …

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A Candidate Magnetic Helium-Core White Dwarf In The Globular Cluster Ngc 6397, Manuel Pichardo Marcano, Liliana E. Rivera Sandoval, Thomas J. Maccarone, Rene D. Rohrmann, Craig O. Heinke, Diogo Belloni, Leandro G. Althaus, Arash Bahramian Mar 2023

A Candidate Magnetic Helium-Core White Dwarf In The Globular Cluster Ngc 6397, Manuel Pichardo Marcano, Liliana E. Rivera Sandoval, Thomas J. Maccarone, Rene D. Rohrmann, Craig O. Heinke, Diogo Belloni, Leandro G. Althaus, Arash Bahramian

Physics & Astronomy Faculty Publications

We report a peculiar variable blue star in the globular cluster (GC) NGC 6397, using Hubble Space Telescope optical imaging. Its position in the colour–magnitude diagrams and its spectrum are consistent with this star being a helium-core white dwarf (He WD) in a binary system. The optical light curve shows a periodicity at 18.5 h. We argue that this periodicity is due to the rotation of the WD and possibly due to magnetic spots on the surface of the WD. This would make this object the first candidate magnetic He WD in any GC, and the first candidate magnetic WD …

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Stellar Atmosphere Models For Select Veritas Stellar Intensity Interferometry Targets, Jackson Ladd Sackrider, Jason P. Aufdenberg, Katelyn Sonnen Mar 2023

Stellar Atmosphere Models For Select Veritas Stellar Intensity Interferometry Targets, Jackson Ladd Sackrider, Jason P. Aufdenberg, Katelyn Sonnen

Beyond: Undergraduate Research Journal

Since 2020 the Very Energetic Radiation Imaging Telescope Array System (VERITAS) has observed 48 stellar targets using the technique of Stellar Intensity Interferometry (SII). Angular diameter measurements by VERITAS SII (VSII) in a waveband near 400 nm complement existing angular diameter measurements in the near-infrared. VSII observations will test fundamental predictions of stellar atmosphere models and should be more sensitive to limb darkening and gravity darkening effects than measurements in the near-IR, however, the magnitude of this difference has not been systematically explored in the literature. In order to investigate the synthetic interferometric (as well as spectroscopic) appearance of stars …

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Wallaby Pilot Survey: Hydra Cluster Galaxies Uv And H I Morphometrics, Benne W. Holwerda, Frank Bigiel, Albert Bosma, Helene M. Courtois, Nathan Deg, Helga Dénes, Ahmed Elagali, Bi-Qing For, Baerbel Koribalski, Denis A. Leahy, Karen Lee-Waddell, Ángel R. López-Sánchez, Se-Heon Oh, Tristan N. Reynolds, Jonghwan Rhee, Kristine Spekkens, Jing Wang, Tobias Westmeier, O Ivy Wong Mar 2023

Wallaby Pilot Survey: Hydra Cluster Galaxies Uv And H I Morphometrics, Benne W. Holwerda, Frank Bigiel, Albert Bosma, Helene M. Courtois, Nathan Deg, Helga Dénes, Ahmed Elagali, Bi-Qing For, Baerbel Koribalski, Denis A. Leahy, Karen Lee-Waddell, Ángel R. López-Sánchez, Se-Heon Oh, Tristan N. Reynolds, Jonghwan Rhee, Kristine Spekkens, Jing Wang, Tobias Westmeier, O Ivy Wong

Faculty and Staff Scholarship

Galaxy morphology in atomic hydrogen (H I) and in the ultraviolet (UV) are closely linked. This has motivated their combined use to quantify morphology over the full H I disc for both H I and UV imaging. We apply galaxy morphometrics: concentration, asymmetry, gini, M20 and multimode-intensity-deviation statistics to the first moment-0 maps of the WALLABY Survey of galaxies in the hydra cluster centre. Taking advantage of this new H I survey, we apply the same morphometrics over the full H I extent on archival GALEX FUV and NUV data to explore how well H I truncated, extended ultraviolet …

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Characterization Of A Set Of Small Planets With Tess And Cheops And An Analysis Of Photometric Performance, D. Oddo, D. Dragomir, A. Brandeker, H. P. Osborn, K. Collins, K. G. Stassun, N. Astudillo-Defru, A. Bieryla, S. B. Howell, D. R. Ciardi, S. Quinn, J. M. Almenara, C. Briceño, K. I. Collins, K. D. Colón, D. M. Conti, N. Crouzet, E. Furlan, T. Gan, C. L. Gnilka, R. F. Goeke, E. Gonzales, M. Harris, J. M. Jenkins, Eric L.N. Jensen, D. Latham, N. Law, M. B. Lund, A. W. Mann, B. Massey, F. Murgas, G. Ricker, H. M. Relles, P. Rowden, R. P. Schwarz, J. Schlieder, A. Shporer, S. Seager, G. Srdoc, G. Torres, J. D. Twicken, R. Vanderspek, J. N. Winn, C. Ziegler Mar 2023

Characterization Of A Set Of Small Planets With Tess And Cheops And An Analysis Of Photometric Performance, D. Oddo, D. Dragomir, A. Brandeker, H. P. Osborn, K. Collins, K. G. Stassun, N. Astudillo-Defru, A. Bieryla, S. B. Howell, D. R. Ciardi, S. Quinn, J. M. Almenara, C. Briceño, K. I. Collins, K. D. Colón, D. M. Conti, N. Crouzet, E. Furlan, T. Gan, C. L. Gnilka, R. F. Goeke, E. Gonzales, M. Harris, J. M. Jenkins, Eric L.N. Jensen, D. Latham, N. Law, M. B. Lund, A. W. Mann, B. Massey, F. Murgas, G. Ricker, H. M. Relles, P. Rowden, R. P. Schwarz, J. Schlieder, A. Shporer, S. Seager, G. Srdoc, G. Torres, J. D. Twicken, R. Vanderspek, J. N. Winn, C. Ziegler

Physics & Astronomy Faculty Works

The radius valley carries implications for how the atmospheres of small planets form and evolve, but this feature is visible only with highly precise characterizations of many small planets. We present the characterization of nine planets and one planet candidate with both NASA TESS and ESA CHEOPS observations, which adds to the overall population of planets bordering the radius valley. While five of our planets—TOI 118 b, TOI 262 b, TOI 455 b, TOI 560 b, and TOI 562 b—have already been published, we vet and validate transit signals as planetary using follow-up observations for four new TESS planets, including …

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Tess Discovery Of Twin Planets Near 2:1 Resonance Around Early M Dwarf Toi 4342, E. Tey, C. X. Huang, M. Kunimoto, A. Vanderburg, A. Shporer, S. N. Quinn, G. Zhou, K. A. Collins, K. I. Collins, Eric L.N. Jensen, R. P. Schwarz, R. Sefako, T. Gan, E. Furlan, C. L. Gnilka, S. B. Howell, K. V. Lester, C. Ziegler, C. Briceño, N. Law, A. W. Mann, G. R. Ricker, R. K. Vanderspek, D. W. Latham, S. Seager, J. M. Jenkins, J. N. Winn, D. A. Caldwell, D. Charbonneau, C. J. Burke, Z. Essack Mar 2023

Tess Discovery Of Twin Planets Near 2:1 Resonance Around Early M Dwarf Toi 4342, E. Tey, C. X. Huang, M. Kunimoto, A. Vanderburg, A. Shporer, S. N. Quinn, G. Zhou, K. A. Collins, K. I. Collins, Eric L.N. Jensen, R. P. Schwarz, R. Sefako, T. Gan, E. Furlan, C. L. Gnilka, S. B. Howell, K. V. Lester, C. Ziegler, C. Briceño, N. Law, A. W. Mann, G. R. Ricker, R. K. Vanderspek, D. W. Latham, S. Seager, J. M. Jenkins, J. N. Winn, D. A. Caldwell, D. Charbonneau, C. J. Burke, Z. Essack

Physics & Astronomy Faculty Works

With data from the Transiting Exoplanet Survey Satellite (TESS), we showcase improvements to the MIT Quick Look Pipeline (QLP) through the discovery and validation of a multiplanet system around M dwarf TOI 4342 (Tmag = 11.032, M⋆ = 0.63 M⊙, R⋆ = 0.60 R⊙, Teff = 3900 K, d = 61.54 pc). With updates to QLP, including a new multiplanet search, as well as faster cadence data from TESS's First Extended Mission, we discovered two sub-Neptunes (Rb = 2.266 (+0.038)/(-0.038) R⊕ and Rc = 2.415 (+0.043)/(-0.040) R …

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The Jwst Early-Release Science Program For Direct Observations Of Exoplanetary Systems Ii: A 1 To 20 Μm Spectrum Of The Planetary-Mass Companion Vhs 1256-1257 B, Brittany E. Miles, Beth A. Biller, Polychronis Patapis, Kadin Worthen, Emily Rickman, Kielan K.W. Hoch, Andrew Skemer, Marshall D. Perrin, Niall Whiteford, Christine H. Chen, B. Sargent, Sagnick Mukherjee, Caroline V. Morley, Sarah E. Moran, Mickael Bonnefoy, Simon Petrus, Aarynn L. Carter, Elodie Choquet, Sasha Hinkley, Kimberly Ward-Duong, Jarron M. Leisenring, Maxwell A. Millar-Blanchaer, Laurent Pueyo, Shrishmoy Ray, Steph Sallum, Karl R. Stapelfeldt, Jordan M. Stone, Jason J. Wang, Olivier Absil, William O. Balmer, Anthony Boccaletti, Mariangela Bonavita Mar 2023

The Jwst Early-Release Science Program For Direct Observations Of Exoplanetary Systems Ii: A 1 To 20 Μm Spectrum Of The Planetary-Mass Companion Vhs 1256-1257 B, Brittany E. Miles, Beth A. Biller, Polychronis Patapis, Kadin Worthen, Emily Rickman, Kielan K.W. Hoch, Andrew Skemer, Marshall D. Perrin, Niall Whiteford, Christine H. Chen, B. Sargent, Sagnick Mukherjee, Caroline V. Morley, Sarah E. Moran, Mickael Bonnefoy, Simon Petrus, Aarynn L. Carter, Elodie Choquet, Sasha Hinkley, Kimberly Ward-Duong, Jarron M. Leisenring, Maxwell A. Millar-Blanchaer, Laurent Pueyo, Shrishmoy Ray, Steph Sallum, Karl R. Stapelfeldt, Jordan M. Stone, Jason J. Wang, Olivier Absil, William O. Balmer, Anthony Boccaletti, Mariangela Bonavita

Astronomy: Faculty Publications

We present the highest fidelity spectrum to date of a planetary-mass object. VHS 1256 b is a (∼8″, a = 150 au), young, planetary-mass companion that shares photometric colors and spectroscopic features with the directly imaged exoplanets HR 8799c, d, and e. As an L-to-T transition object, VHS 1256 b exists along the region of the color-magnitude diagram where substellar atmospheres transition from cloudy to clear. We observed VHS 1256 b with JWST's NIRSpec IFU and MIRI MRS modes for coverage from 1 to 20 μm at resolutions of ∼1000-3700. Water, methane, carbon monoxide, carbon dioxide, sodium, and potassium are …

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The Tess Grand Unified Hot Jupiter Survey. Ii. Twenty New Giant Planets, S. W. Yee, J. N. Winn, J. D. Hartman, L. G. Bouma, G. Zhou, S. N. Quinn, D. W. Latham, A. Bieryla, J. E. Rodriguez, K. A. Collins, O. Alfaro, K. Barkaoui, C. Beard, A. A. Belinski, Z. Benkhaldoun, P. Benni, K. Bernacki, A. W. Boyle, R. P. Butler, D. A. Caldwell, A. Chontos, J. L. Christiansen, D. R. Ciardi, K. I. Collins, D. M. Conti, J. D. Crane, T. Daylan, C. D. Dressing, J. D. Eastman, Z. Essack, P. Evans, M. E. Everett, S. Fajardo-Acosta, R. Forés-Toribio, E. Furlan, M. Ghachoui, M. Gillon, C. Hellier, I. Helm, A. W. Howard, S. B. Howell, H. Isaacson, E. Jehin, J. M. Jenkins, Eric L.N. Jensen, J. F. Kielkopf, D. Laloum, N. Leonhardes-Barboza, P. Lewin, S. E. Logsdon, J. Lubin, M. B. Lund, M. G. Macdougall, A. W. Mann, N. A. Maslennikova, B. Massey, K. K. Mcleod, J. A. Muñoz, P. Newman, V. Orlov, P. Plavchan, A. Popowicz, F. J. Pozuelos, T. A. Pritchard, D. J. Radford, M. Reefe, G. R. Ricker, A. Rudat, B. S. Safonov, R. P. Schwarz, H. Schweiker, N. J. Scott, S. Seager, S. A. Shectman, C. Stockdale, T.-G. Tan, J. K. Teske, N. B. Thomas, M. Timmermans, R. Vanderspek, D. Vermilion, D. Watanabe, L. M. Weiss, R. G. West, J. Van Zandt, M. Zejmo, C. Ziegler Mar 2023

The Tess Grand Unified Hot Jupiter Survey. Ii. Twenty New Giant Planets, S. W. Yee, J. N. Winn, J. D. Hartman, L. G. Bouma, G. Zhou, S. N. Quinn, D. W. Latham, A. Bieryla, J. E. Rodriguez, K. A. Collins, O. Alfaro, K. Barkaoui, C. Beard, A. A. Belinski, Z. Benkhaldoun, P. Benni, K. Bernacki, A. W. Boyle, R. P. Butler, D. A. Caldwell, A. Chontos, J. L. Christiansen, D. R. Ciardi, K. I. Collins, D. M. Conti, J. D. Crane, T. Daylan, C. D. Dressing, J. D. Eastman, Z. Essack, P. Evans, M. E. Everett, S. Fajardo-Acosta, R. Forés-Toribio, E. Furlan, M. Ghachoui, M. Gillon, C. Hellier, I. Helm, A. W. Howard, S. B. Howell, H. Isaacson, E. Jehin, J. M. Jenkins, Eric L.N. Jensen, J. F. Kielkopf, D. Laloum, N. Leonhardes-Barboza, P. Lewin, S. E. Logsdon, J. Lubin, M. B. Lund, M. G. Macdougall, A. W. Mann, N. A. Maslennikova, B. Massey, K. K. Mcleod, J. A. Muñoz, P. Newman, V. Orlov, P. Plavchan, A. Popowicz, F. J. Pozuelos, T. A. Pritchard, D. J. Radford, M. Reefe, G. R. Ricker, A. Rudat, B. S. Safonov, R. P. Schwarz, H. Schweiker, N. J. Scott, S. Seager, S. A. Shectman, C. Stockdale, T.-G. Tan, J. K. Teske, N. B. Thomas, M. Timmermans, R. Vanderspek, D. Vermilion, D. Watanabe, L. M. Weiss, R. G. West, J. Van Zandt, M. Zejmo, C. Ziegler

Physics & Astronomy Faculty Works

NASA's Transiting Exoplanet Survey Satellite (TESS) mission promises to improve our understanding of hot Jupiters by providing an all-sky, magnitude-limited sample of transiting hot Jupiters suitable for population studies. Assembling such a sample requires confirming hundreds of planet candidates with additional follow-up observations. Here we present 20 hot Jupiters that were detected using TESS data and confirmed to be planets through photometric, spectroscopic, and imaging observations coordinated by the TESS Follow-up Observing Program. These 20 planets have orbital periods shorter than 7 days and orbit relatively bright FGK stars (10.9 < G < 13.0). Most of the planets are comparable in mass to Jupiter, although there are four planets with masses less than that of Saturn. TOI-3976b, the longest-period planet in our sample (P = 6.6 days), may be on a moderately eccentric orbit (e = 0.18 ± 0.06), while observations of the other …

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Calculating MBh Scaling Relations For Agns Using 2d Galaxy Decomposition Software To Analyse Hst Images, Jewel A. Capili Mar 2023

Calculating MBh Scaling Relations For Agns Using 2d Galaxy Decomposition Software To Analyse Hst Images, Jewel A. Capili

Physics

This study uses the 2D galaxy decomposition software GALFIT developed by Dr. Chien Peng to analyse Hubble Space Telescope images of 14 Active Galactic Nuclei (AGNs) and obtain their M_BH-spheroid luminosity scaling relations for comparison with previous studies.

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Aggregate Effects Of Proliferating Low-Earth-Orbit Objects And Implications For Astronomical Data Lost In The Noise, John C. Barentine, Aparna Venkatesan, Jessica Heim, James Lowenthal, Miroslav Kocifaj, Salvador Bará Mar 2023

Aggregate Effects Of Proliferating Low-Earth-Orbit Objects And Implications For Astronomical Data Lost In The Noise, John C. Barentine, Aparna Venkatesan, Jessica Heim, James Lowenthal, Miroslav Kocifaj, Salvador Bará

Astronomy: Faculty Publications

The rising population of artificial satellites and associated debris in low-altitude orbits is increasing the overall brightness of the night sky, threatening ground-based astronomy as well as a diversity of stakeholders and ecosystems reliant on dark skies. We present calculations of the potentially large rise in global sky brightness from space objects in low Earth orbit, including qualitative and quantitative assessments of how professional astronomy may be affected. Debris proliferation is of special concern: we calculate that all log-decades in debris size contribute approximately the same amount of night sky radiance, so debris-generating events are expected to lead to a …

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Correlating Changes In Spot Filling Factors With Stellar Rotation: The Case Of Lkca 4, Facundo Pérez Paolino, Jeffrey S. Bary, Michael S. Petersen, Kimberly Ward-Duong, Benjamin M. Tofflemire, Katherine B. Follette, Heidi Mach Mar 2023

Correlating Changes In Spot Filling Factors With Stellar Rotation: The Case Of Lkca 4, Facundo Pérez Paolino, Jeffrey S. Bary, Michael S. Petersen, Kimberly Ward-Duong, Benjamin M. Tofflemire, Katherine B. Follette, Heidi Mach

Astronomy: Faculty Publications

We present a multi-epoch spectroscopic study of LkCa 4, a heavily spotted non-accreting T Tauri star. Using SpeX at NASA’s Infrared Telescope Facility (IRTF), 12 spectra were collected over five consecutive nights, spanning ≈1.5 stellar rotations. Using the IRTF SpeX Spectral Library, we constructed empirical composite models of spotted stars by combining a warmer (photosphere) standard star spectrum with a cooler (spot) standard weighted by the spot filling factor, f spot. The best-fit models spanned two photospheric component temperatures, T phot = 4100 K (K7V) and 4400 K (K5V), and one spot component temperature, T spot = 3060 K (M5V) …

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Direct Discovery Of The Inner Exoplanet In The Hd 206893 System: Evidence For Deuterium Burning In A Planetary-Mass Companion, S. Hinkley, S. Lacour, G. D. Marleau, A. M. Lagrange, J. J. Wang, J. Kammerer, A. Cumming, M. Nowak, L. Rodet, T. Stolker, W. O. Balmer, S. Ray, M. Bonnefoy, P. Mollière, C. Lazzoni, G. Kennedy, C. Mordasini, R. Abuter, S. Aigrain, A. Amorim, R. Asensio-Torres, C. Babusiaux, M. Benisty, J. P. Berger, H. Beust, S. Blunt, A. Boccaletti, Kimberly Ward-Huong, Et Al Mar 2023

Direct Discovery Of The Inner Exoplanet In The Hd 206893 System: Evidence For Deuterium Burning In A Planetary-Mass Companion, S. Hinkley, S. Lacour, G. D. Marleau, A. M. Lagrange, J. J. Wang, J. Kammerer, A. Cumming, M. Nowak, L. Rodet, T. Stolker, W. O. Balmer, S. Ray, M. Bonnefoy, P. Mollière, C. Lazzoni, G. Kennedy, C. Mordasini, R. Abuter, S. Aigrain, A. Amorim, R. Asensio-Torres, C. Babusiaux, M. Benisty, J. P. Berger, H. Beust, S. Blunt, A. Boccaletti, Kimberly Ward-Huong, Et Al

Astronomy: Faculty Publications

Aims. HD 206893 is a nearby debris disk star that hosts a previously identified brown dwarf companion with an orbital separation of ~ 10 au. Long-Term precise radial velocity (RV) monitoring, as well as anomalies in the system proper motion, has suggested the presence of an additional, inner companion in the system. Methods. Using information from ongoing precision RV measurements with the HARPS spectrograph, as well as Gaia host star astrometry, we have undertaken a multi-epoch search for the purported additional planet using the VLTI/GRAVITY instrument. Results. We report a high-significance detection over three epochs of the companion HD 206893c, …

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Speed Of Sound For Hadronic And Quark Phases In A Magnetic Field, Efrain J. Ferrer, Aric Hackebill Mar 2023

Speed Of Sound For Hadronic And Quark Phases In A Magnetic Field, Efrain J. Ferrer, Aric Hackebill

Physics & Astronomy Faculty Publications

In this paper we calculate the speed of sound for three phases that may exist inside a magnetized hybrid neutron star at different density regions: A hadronic phase at low densities, quark-matter in the magnetic dual chiral density wave (MDCDW) phase at intermediate densities and a free-quark phase modeled by the MIT bag model at higher densities. It is found that the speed of sound exhibits a non-monotonic behavior, that goes from values smaller than the conformal limit ( c 2 s < 1 / 3 ) in the hadronic phase, to peak ( c 2 s > 1 / 3 ) in the MDCDW phase, to finally reach the conformal limit ( c 2 s …

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Non-Hermitian Floquet-Free Analytically Solvable Time-Dependent Systems, Hamed Ghaemi-Dizicheh, Hamidreza Ramezani Mar 2023

Non-Hermitian Floquet-Free Analytically Solvable Time-Dependent Systems, Hamed Ghaemi-Dizicheh, Hamidreza Ramezani

Physics & Astronomy Faculty Publications

The non-Hermitian models, which are symmetric under parity (P) and time-reversal (T) operators, are the cornerstone for the fabrication of new ultra-sensitive optoelectronic devices. However, providing the gain in such systems usually demands precise control of nonlinear processes, limiting their application. In this paper, to bypass this obstacle, we introduce a class of time-dependent non-Hermitian Hamiltonians (not necessarily Floquet) that can describe a two-level system with temporally modulated on-site potential and couplings. We show that implementing an appropriate non-Unitary gauge transformation converts the original system to an effective one with a balanced gain and loss. This …

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Merging Black Holes: Assessing The Performance Of Two Analytic Gravitational Waves Models, Dillon Buskirk, Maria Babiuc-Hamilton Mar 2023

Merging Black Holes: Assessing The Performance Of Two Analytic Gravitational Waves Models, Dillon Buskirk, Maria Babiuc-Hamilton

Physics Faculty Research

Merging black holes produce the loudest signal in the detectors. However, this is the most difficult signal to accurately predict with analytical techniques. Only computer simulations can account for the nonlinear physics during the collision, but they are inherently complex, costly, and affected by numerical errors. In order to bypass this problem, two analytical models for the merger have been developed: the Implicit Rotating Source (IRS) and the newer Backwards one Body (BoB). In this work, we assess the performance of the BoB model by comparing it with the older IRS model and with the numerical data, identifying its strengths …

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Evolution Of Coronal Magnetic Field Parameters During X5.4 Solar Flare, Seth H. Garland, Benjamin F. Akers, Vasyl B. Yurchyshyn, Robert D. Loper, Daniel J. Emmons Mar 2023

Evolution Of Coronal Magnetic Field Parameters During X5.4 Solar Flare, Seth H. Garland, Benjamin F. Akers, Vasyl B. Yurchyshyn, Robert D. Loper, Daniel J. Emmons

Faculty Publications

The coronal magnetic field over NOAA Active Region 11,429 during a X5.4 solar flare on 7 March 2012 is modeled using optimization based Non-Linear Force-Free Field extrapolation. Specifically, 3D magnetic fields were modeled for 11 timesteps using the 12-min cadence Solar Dynamics Observatory (SDO) Helioseismic and Magnetic Imager photospheric vector magnetic field data, spanning a time period of 1 hour before through 1 hour after the start of the flare. Using the modeled coronal magnetic field data, seven different magnetic field parameters were calculated for 3 separate regions: areas with surface |Bz| ≥ 300 G, areas of flare brightening seen …

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Clumpy Wind Studies And The Nondetection Of A Cyclotron Line In Oao 1657–415, Pragati Pradhan, Carlo Ferrigno, Biswajit Paul, Enrico Bozzo, Ileyk El Mellah, David P. Huenemoerder, James F. Steiner, Victoria Grinberg, Felix Furst, Chandreyee Maitra, Patrizia Romano, Peter Kretschmar, Jamie Kennea, Deepto Chakrabarty Mar 2023

Clumpy Wind Studies And The Nondetection Of A Cyclotron Line In Oao 1657–415, Pragati Pradhan, Carlo Ferrigno, Biswajit Paul, Enrico Bozzo, Ileyk El Mellah, David P. Huenemoerder, James F. Steiner, Victoria Grinberg, Felix Furst, Chandreyee Maitra, Patrizia Romano, Peter Kretschmar, Jamie Kennea, Deepto Chakrabarty

Publications

Winds of massive stars are suspected to be inhomogeneous (or clumpy), which biases the measures of their mass-loss rates. In high-mass X-ray binaries (HMXBs), the compact object can be used as an orbiting X-ray point source to probe the wind and constrain its clumpiness. We perform a spectrotiming analysis of the HMXB OAO 1657–415 with nonsimultaneous NuSTAR and NICER observations. We compute the hardness ratio from the energy-resolved light curves, and, using an adaptive rebinning technique, we thus select appropriate time segments to search for rapid spectral variations on timescales of a few hundred to thousands of seconds. The column …

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