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Articles 511 - 540 of 2944

Full-Text Articles in Astrophysics and Astronomy

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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Three- And Four-Point Functions In Cpt -Even Lorentz-Violating Scalar Qed, Brett Altschul, L. C.T. Brito, J. C.C. Felipe, S. Karki, A. C. Lehum, A. Yu Petrov Feb 2023

Three- And Four-Point Functions In Cpt -Even Lorentz-Violating Scalar Qed, Brett Altschul, L. C.T. Brito, J. C.C. Felipe, S. Karki, A. C. Lehum, A. Yu Petrov

Faculty Publications

The renormalization of quantum field theories usually assumes Lorentz and gauge symmetries, besides the general restrictions imposed by unitarity and causality. However, the set of renormalizable theories can be enlarged by relaxing some of these assumptions. In this work, we consider the particular case of a CPT-preserving but Lorentz-breaking extension of scalar QED. For this theory, we calculate the one-loop radiative corrections to the three- and four-point scalar-vector vertex functions, at the lowest order in the Lorentz-violation parameters, and we explicitly verify that the resulting low-energy effective action is compatible with the usual gauge invariance requirements. With these results, we …

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Measurement Of The VE- Nucleus Charged-Current Double-Differential Cross Section At 〈EV⟩ = 2.4 Gev Using Nova, M. A. Acero, P. Adamson, L. Aliaga, N. Anfimov, A. Antoshkin, E. Arrieta-Diaz, L. Asquith, A. Aurisano, A. Back, M. Biard, N. Balashov, P. Baldi, B. A. Bambah, S. Bashar, K. Bays, R. Bernstein, V. Bhatnagar, D. Bhattarai, B. Bhuyan, J. Bian, Roberto Petti, Et. Al. Feb 2023

Measurement Of The VE- Nucleus Charged-Current Double-Differential Cross Section At 〈EV⟩ = 2.4 Gev Using Nova, M. A. Acero, P. Adamson, L. Aliaga, N. Anfimov, A. Antoshkin, E. Arrieta-Diaz, L. Asquith, A. Aurisano, A. Back, M. Biard, N. Balashov, P. Baldi, B. A. Bambah, S. Bashar, K. Bays, R. Bernstein, V. Bhatnagar, D. Bhattarai, B. Bhuyan, J. Bian, Roberto Petti, Et. Al.

Faculty Publications

The inclusive electron neutrino charged-current cross section is measured in the NOvA near detector using 8.02×1020 protons-on-target in the NuMI beam. The sample of GeV electron neutrino interactions is the largest analyzed to date and is limited by ≃17% systematic rather than the ≃7.4% statistical uncertainties. The double-differential cross section in final-state electron energy and angle is presented for the first time, together with the single-differential dependence on Q2 (squared four-momentum transfer) and energy, in the range 1  GeV≤EνGENIE, GiBUU, NEUT, and NuWro neutrino event generators. The data do not strongly favor a model over the …

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Galfit-Ing Agn Host Galaxies In Cosmos: Hst Versus Subaru, Callum Dewsnap, Pauline Barmby, Sarah C. Gallagher, C. Megan Urry, Aritra Ghosh, Meredith C. Powell Feb 2023

Galfit-Ing Agn Host Galaxies In Cosmos: Hst Versus Subaru, Callum Dewsnap, Pauline Barmby, Sarah C. Gallagher, C. Megan Urry, Aritra Ghosh, Meredith C. Powell

Physics and Astronomy Publications

The COSMOS field has been extensively observed by most major telescopes, including Chandra, HST, and Subaru. HST imaging boasts very high spatial resolution and is used extensively in morphological studies of distant galaxies. Subaru provides lower spatial resolution imaging than HST but a substantially wider field of view with greater sensitivity. Both telescopes provide near-infrared imaging of COSMOS. Successful morphological fitting of Subaru data would allow us to measure morphologies of over 104 known active galactic nucleus (AGN) hosts, accessible through Subaru wide-field surveys, currently not covered by HST. The morphological parameters indicate the types of galaxies that host AGNs. …

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Wallaby Pilot Survey: H I Gas Kinematics Of Galaxy Pairs In Cluster Environment, Shin-Jeong Kim, Se-Heon Oh, Jing Wang, Lister Staveley-Smith, Bärbel S. Koribalski, Minsu Kim, Hye-Jin Park, Shinna Kim, Kristine Spekkens, Juan P. Madrid Feb 2023

Wallaby Pilot Survey: H I Gas Kinematics Of Galaxy Pairs In Cluster Environment, Shin-Jeong Kim, Se-Heon Oh, Jing Wang, Lister Staveley-Smith, Bärbel S. Koribalski, Minsu Kim, Hye-Jin Park, Shinna Kim, Kristine Spekkens, Juan P. Madrid

Physics & Astronomy Faculty Publications

We examine the H I gas kinematics of galaxy pairs in two clusters and a group using Australian Square Kilometre Array Pathfinder (ASKAP) WALLABY pilot survey observations. We compare the H I properties of galaxy pair candidates in the Hydra I and Norma clusters, and the NGC 4636 group, with those of non-paired control galaxies selected in the same fields. We perform H I profile decomposition of the sample galaxies using a tool, BAYGAUD, which allows us to deblend a line-of-sight velocity profile with an optimal number of Gaussian components. We construct H I superprofiles of the sample galaxies via …

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Effects Of Silicon Dioxide As The Polar Dielectric On The Infrared Absorption Spectrum Ofthemetal-Insulator-Metal Metasurface, Ahmad K. Jafari, Matthew Gaddy, Imtiaz Ahmad, Satya R. Kachiraju, M D. Borhan Mia, Ishtiaque Ahmed, Sergey Nikishin, Myoung-Hwan Kim, Ayrton A. Bernussi Jan 2023

Effects Of Silicon Dioxide As The Polar Dielectric On The Infrared Absorption Spectrum Ofthemetal-Insulator-Metal Metasurface, Ahmad K. Jafari, Matthew Gaddy, Imtiaz Ahmad, Satya R. Kachiraju, M D. Borhan Mia, Ishtiaque Ahmed, Sergey Nikishin, Myoung-Hwan Kim, Ayrton A. Bernussi

Physics & Astronomy Faculty Publications

Metal-insulator-metal metasurfaces have been widely used as high-performance absorbers in almost all electromagnetic spectral ranges. Their absorption spectra can be engineered by making variations in the geometry of the unit cells and/or by embedding materials with specific optical constants. Including a polar dielectric in their structure is another approach for manipulating their absorption spectra. In this research, we have numerically and experimentally investigated the effect of using silicon dioxide (SiO2) as a polar dielectric on the absorption spectrum of a metal-insulator-metal metasurface composed of a tri-layer of Ni-SiO2-Ni. Our results have shown the presence of …

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Measurement Of Near-Threshold Proton Branching Ratios In 31s Important For Novae, Sudarsan Balakrishnan Jan 2023

Measurement Of Near-Threshold Proton Branching Ratios In 31s Important For Novae, Sudarsan Balakrishnan

LSU Doctoral Dissertations

Classical novae are stellar explosions that contribute to the nucleosynthesis of isotopes on the proton-rich side of the valley of stability up to 40Ca. In ONe novae, the incompletely understood reaction rate of 30P(p,γ)31S is known to strongly influence the production rate of several stable isotopes such as 30Si, 31P, and 32,33,34S. A precise measurement of this reaction rate has several potential implications towards matching astrophysical observables to the physical composition of the nova site -- the observed elemental abundance ratios of O/S and S/Al have been suggested as useful `thermometers' to gauge …

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Advanced Thermoluminescence Spectroscopy As A Research Tool For Semiconductor And Photonic Materials: A Review And Perspective, Farida Selim Jan 2023

Advanced Thermoluminescence Spectroscopy As A Research Tool For Semiconductor And Photonic Materials: A Review And Perspective, Farida Selim

Physics and Astronomy Faculty Publications

Thermoluminescence (TL) or thermally stimulated luminescence (TSL) spectroscopy is based on liberating charge carriers from traps in the bandgap by providing enough thermal energy to overcome the potential barrier of the traps. It provides a powerful tool to measure the positions of the localized states/traps in the bandgap. Despite that, its applications in semiconductors are very limited. Herein, the basics of TL spectroscopy and the recent advances in the technique with focus on cryogenic thermally stimulated photoemission spectroscopy (C-TSPS) which extends TL measurements to cryogenic regime and allows the detection of very low concentrations of shallow and deep localized states …

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Solar Cells, Lambert W And The Logwright Functions, Prabhat Lankireddy, Sibibalan Jeevanandam, Aditya Chaudhary, P. C. Deshmukh, Ken Roberts, S. R. Valluri Jan 2023

Solar Cells, Lambert W And The Logwright Functions, Prabhat Lankireddy, Sibibalan Jeevanandam, Aditya Chaudhary, P. C. Deshmukh, Ken Roberts, S. R. Valluri

Physics and Astronomy Publications

Algorithms that calculate the current-voltage (I-V) characteristics of a solar cell play an important role in processes that aim to improve the efficiency of a solar cell. I-V characteristics can be obtained from different models used to represent the solar cell, and the single diode model is a simple yet accurate model for common field implementations. However, the I-V characteristics are obtained by solving implicit equations, which involve repeated iterations and inherent errors associated with numerical methods used. Some methods use the Lambert W function to get an exact explicit formula, but often causes numerical overflow problems. The present work …

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Modelling Of Covid-19 Using Fractional Differential Equations, Rishi Patel, P. Sainani, M. Brar, R. Patel, X. Li, J. Drozd, F. A. Chishtie, A. Benterki, T. C. Scott, S. R. Valluri Jan 2023

Modelling Of Covid-19 Using Fractional Differential Equations, Rishi Patel, P. Sainani, M. Brar, R. Patel, X. Li, J. Drozd, F. A. Chishtie, A. Benterki, T. C. Scott, S. R. Valluri

Physics and Astronomy Publications

In this work, we have described the mathematical modeling of COVID-19 transmission using fractional differential equations. The mathematical modeling of infectious disease goes back to the 1760s when the famous mathematician Daniel Bernoulli used an elementary version of compartmental modeling to find the effectiveness of deliberate smallpox inoculation on life expectancy. We have used the well-known SIR (Susceptible, Infected and Recovered) model of Kermack & McKendrick to extend the analysis further by including exposure, quarantining, insusceptibility and deaths in a SEIQRDP model. Further, we have generalized this model by using the solutions of Fractional Differential Equations to test the accuracy …

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The Role Of R-Modes In Pulsar Spindown, Pulsar Timing And Gravitational Waves, Varenya Upadhyaya, Xiyuan Li, Xiyang Zhang, S. R. Valluri Jan 2023

The Role Of R-Modes In Pulsar Spindown, Pulsar Timing And Gravitational Waves, Varenya Upadhyaya, Xiyuan Li, Xiyang Zhang, S. R. Valluri

Physics and Astronomy Publications

Pulsars are fast spinning neutron stars that lose their rotational energy via various processes such as gravitational and magnetic radiation, particle acceleration and mass loss processes. This dissipation can be quantified by a spin-down equation that measures the rate of change of the frequency as a function of the rotational frequency itself. We explore the pulsar spin-down and consider the spin-down equation upto the seventh order in frequency. This seventh order term accounts for energy loss due to the gravitational radiation caused by a current type quadrupole in the pulsar due to r-modes. We derive the rotational frequency due to …

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Jwst/Nirspec Measurements Of The Relationships Between Nebular Emission-Line Ratios And Stellar Mass At Z ∼ 3–6, Alice E. Shapley, Naveen Reddy, Ryan L. Sanders, Michael W. Topping, Gabriel B. Brammer Jan 2023

Jwst/Nirspec Measurements Of The Relationships Between Nebular Emission-Line Ratios And Stellar Mass At Z ∼ 3–6, Alice E. Shapley, Naveen Reddy, Ryan L. Sanders, Michael W. Topping, Gabriel B. Brammer

Physics and Astronomy Faculty Publications

We analyze the rest-optical emission-line ratios of star-forming galaxies at 2.7 ≤ z < 6.5 drawn from the Cosmic Evolution Early Release Science (CEERS) Survey and their relationships with stellar mass (M *). Our analysis includes both line ratios based on the [N ii] λ6583 feature ([N ii] λ6583/Hα, ([O iii] λ5007/Hβ)/([N ii] λ6583/Hα) (O3N2), and [N ii] λ6583/[O ii] λ3727) and those featuring α-elements ([O iii] λ5007/Hβ, [O iii] λ5007/[O ii] λ3727 (O32), ([O iii] λλ4959, 5007 + [O ii] λ3727)/Hβ (R23), and [Ne iii] λ3869/[O ii] λ3727). Given the typical flux levels of [N ii] λ6583 and [Ne iii] λ3869, which are undetected in the majority of individual CEERS galaxies at 2.7 …

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Higher-Order Cumulants And Correlation Functions Of Proton Multiplicity Distributions In √Snn = 3 Gev Au+Au Collisions At The Rhic Star Experiment, The Star Collaboration Jan 2023

Higher-Order Cumulants And Correlation Functions Of Proton Multiplicity Distributions In √Snn = 3 Gev Au+Au Collisions At The Rhic Star Experiment, The Star Collaboration

Physics and Astronomy Faculty Publications

We report a measurement of cumulants and correlation functions of event-by-event proton multiplicity distributions from fixed-target Au+Au collisions at √sNN = 3 GeV measured by the STAR experiment. Protons are identified within the rapidity (y) and transverse momentum (pT ) region −0.9 < y < 0 and 0.4 < pT < 2.0 GeV/c in the center-of-mass frame. A systematic analysis of the proton cumulants and correlation functions up to sixth order as well as the corresponding ratios as a function of the collision centrality, pT , and y are presented. The effect of pileup and initial volume fluctuations on these observables and the respective corrections are discussed in detail. The results are compared to calculations from the hadronic transport UrQMD model as well as a hydrodynamic model. In the most central 5% collisions, the value of proton cumulant ratio C4/C2 is negative, drastically different from the values observed in Au+Au collisions at higher energies. Compared to model calculations including lattice QCD, a hadronic transport model, and a hydrodynamic model, the strong suppression in the ratio of C4/C2 at 3 GeV Au+Au collisions indicates an energy regime dominated by hadronic interactions.

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Azimuthal Anisotropy Measurement Of (Multi)Strange Hadrons In Au+Au Collisions At √S Nn = 54.4 Gev, Star Collaboration Jan 2023

Azimuthal Anisotropy Measurement Of (Multi)Strange Hadrons In Au+Au Collisions At √S Nn = 54.4 Gev, Star Collaboration

Physics and Astronomy Faculty Publications

Azimuthal anisotropy of produced particles is one of the most important observables used to access the collective properties of the expanding medium created in relativistic heavy-ion collisions. In this paper, we present second (v2) and third (v3) order azimuthal anisotropies of KS0, φ, Λ, Ξ, and ω at midrapidity (|y|< 1) in Au+Au collisions at sNN=54.4 GeV measured by the STAR detector. The v2 and v3 are measured as a function of transverse momentum and centrality. Their energy dependence is also studied. v3 is found to be more sensitive to the change in the center-of-mass energy than v2. Scaling by constituent quark number is found to hold for v2 within 10%. This observation could be evidence for the development of partonic collectivity in 54.4 GeV Au+Au collisions. Differences in v2 and v3 between baryons and antibaryons are presented, and ratios of v3/v23/2 are studied and motivated by hydrodynamical calculations. The ratio of v2 of φ mesons to that of antiprotons [v2(φ)/v2(p¯)] shows centrality dependence at low transverse momentum, presumably resulting from the larger effects from hadronic interactions on antiproton v2.

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Gauging The Mass Of Metals In The Gas Phase Of Galaxies From The Local Universe To The Epoch Of Reionization, K. E. Heintz, Alice E. Shapley, Ryan L. Sanders, M. Killi, D. Watson, G. Magdis, F. Valentino, M. Ginolfi, D. Narayanan, T. R. Greve, J. P. U. Fynbo, D. Vizgan, S. N. Wilson Jan 2023

Gauging The Mass Of Metals In The Gas Phase Of Galaxies From The Local Universe To The Epoch Of Reionization, K. E. Heintz, Alice E. Shapley, Ryan L. Sanders, M. Killi, D. Watson, G. Magdis, F. Valentino, M. Ginolfi, D. Narayanan, T. R. Greve, J. P. U. Fynbo, D. Vizgan, S. N. Wilson

Physics and Astronomy Faculty Publications

The chemical enrichment of dust and metals are vital processes in constraining the star formation history of the universe. These are important ingredients in the formation and evolution of galaxies overall. Previously, the dust masses of high-redshift star-forming galaxies have been determined through their far-infrared continuum, however, equivalent, and potentially simpler, approaches to determining the metal masses have yet to be explored at z ≳ 2. Here, we present a new method of inferring the metal mass in the interstellar medium (ISM) of galaxies out to z 8, using the far-infrared [C II]- 158† μm emission line as a proxy. …

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Jwst/Nirspec Balmer-Line Measurements Of Star Formation And Dust Attenuation At Z ∼ 3–6, Alice E. Shapley, Ryan L. Sanders, Naveen Reddy, Michael W. Topping, Gabriel B. Brammer Jan 2023

Jwst/Nirspec Balmer-Line Measurements Of Star Formation And Dust Attenuation At Z ∼ 3–6, Alice E. Shapley, Ryan L. Sanders, Naveen Reddy, Michael W. Topping, Gabriel B. Brammer

Physics and Astronomy Faculty Publications

We present an analysis of the star formation rates (SFRs) and dust attenuation properties of star-forming galaxies at 2.7 ≤ z < 6.5 drawn from the Cosmic Evolution Early Release Science Survey. Our analysis is based on JWST/NIRSpec Micro-Shutter Assembly R ∼ 1000 spectroscopic observations covering approximately 1-5 μm. Our primary rest-frame optical spectroscopic measurements are Hα/Hβ Balmer decrements, which we use as an indicator of nebular dust attenuation. In turn, we use Balmer decrements to obtain dust-corrected Hα-based SFRs (i.e., SFR(Hα)). We construct the relationship between SFR(Hα) and stellar mass (M *) in three bins of redshift (2.7 ≤ z < 4.0, 4.0 ≤ z < 5.0, and 5.0 ≤ z < 6.5), which represents the first time the star-forming main sequence has been traced at these redshifts using direct spectroscopic measurements of Balmer emission as a proxy for SFR. In tracing the relationship between SFR(Hα) and M * back to such early times (z > 3), it is essential to use a conversion factor between Hα and SFR that accounts for the subsolar metallicity prevalent among distant galaxies. We also use measured Balmer decrements to investigate the relationship between dust attenuation and stellar mass out to z ∼ 6. The lack of significant redshift evolution in attenuation at fixed stellar mass, previously confirmed using Balmer decrements out …

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Azimuthal Anisotropy Measurement Of (Multi)Strange Hadrons In Au+Au Collisions At √𝑠𝑁⁢𝑁=54.4 Gev, Star Collaboration Jan 2023

Azimuthal Anisotropy Measurement Of (Multi)Strange Hadrons In Au+Au Collisions At √𝑠𝑁⁢𝑁=54.4 Gev, Star Collaboration

Physics and Astronomy Faculty Publications

Azimuthal anisotropy of produced particles is one of the most important observables used to access the collective properties of the expanding medium created in relativistic heavy-ion collisions. In this paper, we present second (v2) and third (v3) order azimuthal anisotropies of KS0, φ, Λ, Ξ, and ω at midrapidity (|y|< 1) in Au+Au collisions at sNN=54.4 GeV measured by the STAR detector. The v2 and v3 are measured as a function of transverse momentum and centrality. Their energy dependence is also studied. v3 is found to be more sensitive to the change in the center-of-mass energy than v2. Scaling by constituent quark number is found to hold for v2 within 10%. This observation could be evidence for the development of partonic collectivity in 54.4 GeV Au+Au collisions. Differences in v2 and v3 between baryons and antibaryons are presented, and ratios of v3/v23/2 are studied and motivated by hydrodynamical calculations. The ratio of v2 of φ mesons to that of antiprotons [v2(φ)/v2(p¯)] shows centrality dependence at low transverse momentum, presumably resulting from the larger effects from hadronic interactions on antiproton v2.

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Beam Energy Dependence Of Fifth- And Sixth-Order Net-Proton Number Fluctuations In Au + Au Collisions At Rhic, Star Collaboration Jan 2023

Beam Energy Dependence Of Fifth- And Sixth-Order Net-Proton Number Fluctuations In Au + Au Collisions At Rhic, Star Collaboration

Physics and Astronomy Faculty Publications

We report the beam energy and collision centrality dependence of fifth and sixth order cumulants (C5, C6) and factorial cumulants (κ5, κ6) of net-proton and proton number distributions, from center-of-mass energy (sNN) 3 GeV to 200 GeV Au+Au collisions at RHIC. Cumulant ratios of net-proton (taken as proxy for net-baryon) distributions generally follow the hierarchy expected from QCD thermodynamics, except for the case of collisions at 3 GeV. The measured values of C6/C2 for 0%-40% centrality collisions show progressively negative trend with decreasing energy, while it is positive for the lowest energy studied. These observed negative signs are consistent with …

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Measurement Of Sequential ϒ Suppression In Au + Au Collisions At √Snn = 200 Gev With The Star Experiment, Star Collaboration Jan 2023

Measurement Of Sequential ϒ Suppression In Au + Au Collisions At √Snn = 200 Gev With The Star Experiment, Star Collaboration

Physics and Astronomy Faculty Publications

We report on measurements of sequential ϒ suppression in Au+Au collisions at sNN=200 GeV with the STAR detector at the Relativistic Heavy Ion Collider (RHIC) through both the dielectron and dimuon decay channels. In the 0%-60% centrality class, the nuclear modification factors (RAA), which quantify the level of yield suppression in heavy-ion collisions compared to p+p collisions, for ϒ(1S) and ϒ(2S) are 0.40±0.03(stat)±0.03(sys)±0.09(norm) and 0.26±0.08(stat)±0.02(sys)±0.06(norm), respectively, while the upper limit of the ϒ(3S) RAA is 0.17 at a 95% confidence level. This provides experimental evidence that the ϒ(3S) is significantly more suppressed than the ϒ(1S) at RHIC. The level of …

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Measurementus Magnetic Moment To 0.20 Ppm Of The Positive Muon Anomalo, The Muon G − 2 Collaboration Jan 2023

Measurementus Magnetic Moment To 0.20 Ppm Of The Positive Muon Anomalo, The Muon G − 2 Collaboration

Physics and Astronomy Faculty Publications

We present a new measurement of the positive muon magnetic anomaly, aμ(gμ-2)/2, from the Fermilab Muon g-2 Experiment using data collected in 2019 and 2020. We have analyzed more than 4 times the number of positrons from muon decay than in our previous result from 2018 data. The systematic error is reduced by more than a factor of 2 due to better running conditions, a more stable beam, and improved knowledge of the magnetic field weighted by the muon distribution, p′, and of the anomalous precession frequency corrected for beam dynamics effects, ωa. From the ratio ωa/p′, together with precisely …

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Ai-Assisted Optimization Of The Ecce Tracking System At The Electron Ion Collider, C. Fanelli, Z. Papandreou, K. Suresh Jan 2023

Ai-Assisted Optimization Of The Ecce Tracking System At The Electron Ion Collider, C. Fanelli, Z. Papandreou, K. Suresh

Physics and Astronomy Faculty Publications

The Electron-Ion Collider (EIC) is a cutting-edge accelerator facility that will study the nature of the ‘‘glue’’ that binds the building blocks of the visible matter in the universe. The proposed experiment will be realized at Brookhaven National Laboratory in approximately 10 years from now, with detector design and R&D currently ongoing. Notably, EIC is one of the first large-scale facilities to leverage Artificial Intelligence (AI) already starting from the design and R&D phases. The EIC Comprehensive Chromodynamics Experiment (ECCE) is a consortium that proposed a detector design based on a 1.5 T solenoid. The EIC detector proposal review concluded …

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Scientific Computing Plan For The Ecce Detector At The Electron Ion Collider, J. C. Bernauer, C. T. Dean, C. Fanelli, J. Huang, K. Kauder, D. Lawrence, J. D. Osborn Jan 2023

Scientific Computing Plan For The Ecce Detector At The Electron Ion Collider, J. C. Bernauer, C. T. Dean, C. Fanelli, J. Huang, K. Kauder, D. Lawrence, J. D. Osborn

Physics and Astronomy Faculty Publications

The Electron Ion Collider (EIC) is the next generation of precision QCD facility to be built at Brookhaven National Laboratory in conjunction with Thomas Jefferson National Laboratory. There are a significant number of software and computing challenges that need to be overcome at the EIC. During the EIC detector proposal development period, the ECCE consortium began identifying and addressing these challenges in the process of producing a complete detector proposal based upon detailed detector and physics simulations. In this document, the software and computing efforts to produce this proposal are discussed; furthermore, the computing and software model and resources required …

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Paschen-Line Constraints On Dust Attenuation And Star Formation At Z ∼ 1–3 With Jwst/ Nirspec, Naveen Reddy, Michael W. Topping, Ryan L. Sanders, Alice E. Shapley, Gabriel B. Brammer Jan 2023

Paschen-Line Constraints On Dust Attenuation And Star Formation At Z ∼ 1–3 With Jwst/ Nirspec, Naveen Reddy, Michael W. Topping, Ryan L. Sanders, Alice E. Shapley, Gabriel B. Brammer

Physics and Astronomy Faculty Publications

We use medium-resolution JWST/NIRSpec observations from the Cosmic Evolution Early Release Science Survey to place the first constraints on dust attenuation and star formation based on Paschen lines for a sizable sample of 63 galaxies at redshifts z = 1.0-3.1. Our analysis indicates strong correlations between the Balmer decrement, Hα/Hβ, and line ratios that include Paschen lines (i.e., Paα/Hβ, Paβ/Hβ, and the Paschen decrement, Paα/Paβ), suggesting that the former is sensitive to the overall dust obscuration toward H ii regions in high-redshift galaxies. The line ratios are used to derive nebular reddening, E(B − V)neb, and star formation …

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The Gas And Stellar Content Of A Metal-Poor Galaxy At Z = 8.496 As Revealed By Jwst And Alma, K. E. Heintz, C. Giménez-Arteaga, S. Fujimoto, Gabriel B. Brammer, D. Espada, S. Gillman, J. González-López, T. R. Greve, Yuichi Harikane, B. Hatsukade, K. K. Knudsen, Anton M. Koekemoer, K. Kohno, V. Kokorev, M. M. Lee, Georgios E. Magdis, E. J. Nelson, F. Rizzo, Ryan L. Sanders, D. Schaerer, Alice E. Shapley, V. B. Strait, S. Toft, F. Valentino, A. Van Der Wel, A. P. Vijayan, D. Watson, F. E. Bauer, Amber Christiansen, C. R. Christiansen, S. N. Wilson Jan 2023

The Gas And Stellar Content Of A Metal-Poor Galaxy At Z = 8.496 As Revealed By Jwst And Alma, K. E. Heintz, C. Giménez-Arteaga, S. Fujimoto, Gabriel B. Brammer, D. Espada, S. Gillman, J. González-López, T. R. Greve, Yuichi Harikane, B. Hatsukade, K. K. Knudsen, Anton M. Koekemoer, K. Kohno, V. Kokorev, M. M. Lee, Georgios E. Magdis, E. J. Nelson, F. Rizzo, Ryan L. Sanders, D. Schaerer, Alice E. Shapley, V. B. Strait, S. Toft, F. Valentino, A. Van Der Wel, A. P. Vijayan, D. Watson, F. E. Bauer, Amber Christiansen, C. R. Christiansen, S. N. Wilson

Physics and Astronomy Faculty Publications

We present a joint analysis of the galaxy S04590 at z = 8.496 based on NIRSpec, NIRCam, and NIRISS observations obtained as part of the Early Release Observations program of the James Webb Space Telescope (JWST) and the far-infrared [C ii] 158 μm emission line detected by dedicated Atacama Large Millimeter/submillimeter Array (ALMA) observations. We determine the physical properties of S04590 from modeling of the spectral energy distribution (SED) and through the redshifted optical nebular emission lines detected with JWST/NIRSpec. The best-fit SED model reveals a low-mass (M ⋆ = 107.2-108 M ⊙) galaxy with a …

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A Jwst/Nirspec Exploration Of The Connection Between Ionization Parameter, Electron Density, And Star-Formation-Rate Surface Density In Z = 2.7–6.3 Galaxies, Naveen Reddy, Michael W. Topping, Ryan L. Sanders, Alice E. Shapley, Gabriel B. Brammer Jan 2023

A Jwst/Nirspec Exploration Of The Connection Between Ionization Parameter, Electron Density, And Star-Formation-Rate Surface Density In Z = 2.7–6.3 Galaxies, Naveen Reddy, Michael W. Topping, Ryan L. Sanders, Alice E. Shapley, Gabriel B. Brammer

Physics and Astronomy Faculty Publications

We examine the factors responsible for the variation in the ionization parameter (U) of high-redshift star-forming galaxies based on medium-resolution JWST/NIRSpec observations obtained by the Cosmic Evolution Early Release Science survey. The sample consists of 48 galaxies with redshifts zspec = 2.7−6.3, which are largely representative of typical galaxies at these redshifts. The [S II] λλ6718, 6733 doublet is used to estimate electron densities (n e), and dust-corrected Hα luminosities are used to compute ionizing photon rates (Q). Using composite spectra of galaxies in bins of [O III] λλ4960, 5008/[O II] λλ3727, 3730 (O32) as a proxy for U, we …

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An Updated Dust-To-Star Geometry: Dust Attenuation Does Not Depend On Inclination In 1.3 <= Z <= 2.6 Star-Forming Galaxies From Mosdef, Brian Lorenz, Mariska Kriek, Alice E. Shapley, Naveen Reddy, Ryan L. Sanders, Guillermo Barro, Alison L. Coil, Bahram Mobasher, Sedona H. Price, Jordan N. Runco, Irene Shivaei, Brian Siana, Daniel R. Weisz Jan 2023

An Updated Dust-To-Star Geometry: Dust Attenuation Does Not Depend On Inclination In 1.3 <= Z <= 2.6 Star-Forming Galaxies From Mosdef, Brian Lorenz, Mariska Kriek, Alice E. Shapley, Naveen Reddy, Ryan L. Sanders, Guillermo Barro, Alison L. Coil, Bahram Mobasher, Sedona H. Price, Jordan N. Runco, Irene Shivaei, Brian Siana, Daniel R. Weisz

Physics and Astronomy Faculty Publications

We investigate dust attenuation and its dependence on viewing angle for 308 star-forming galaxies at 1.3 < = z < = 2.6 from the MOSFIRE Deep Evolution Field survey. We divide galaxies with a detected Hα emission line and coverage of Hβ into eight groups by stellar mass, star formation rate (SFR), and inclination (i.e., axis ratio), and we then stack their spectra. From each stack, we measure the Balmer decrement and gas-phase metallicity, and then we compute the median AV and UV continuum spectral slope (β). First, we find that none of the dust properties (Balmer decrement, AV , or β) varies with the axis ratio. Second, both stellar and nebular attenuation increase with increasing galaxy mass, showing little residual dependence on SFR or metallicity. Third, nebular emission is more attenuated than stellar emission, and this difference grows even larger at higher galaxy masses and SFRs. Based on these results, we propose a three-component dust model in which attenuation predominantly occurs in star-forming regions and large, dusty star-forming clumps, with minimal attenuation in the diffuse ISM. In this model, nebular attenuation primarily originates in clumps, while stellar attenuation is dominated by star-forming regions. Clumps become larger and more common with increasing galaxy mass, creating the above mass trends. Finally, we argue that a fixed metal yield naturally leads to mass regulating dust attenuation. Infall of low-metallicity gas increases the SFR and lowers the metallicity, but leaves the dust column density mostly unchanged. We quantify this idea using the Kennicutt–Schmidt and fundamental metallicity relations, showing that galaxy mass is indeed the primary driver of dust attenuation.

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A Preview Of Jwst Metallicity Studies At Cosmic Noon: The First Detection Of Auroral [O Ii] Emission At High Redshift, Ryan L. Sanders, Alice E. Shapley, Leonardo Clarke, Michael W. Topping, Naveen Reddy, Mariska Kriek, Tucker Jones, Daniel P. Stark, Mengtao Tang Jan 2023

A Preview Of Jwst Metallicity Studies At Cosmic Noon: The First Detection Of Auroral [O Ii] Emission At High Redshift, Ryan L. Sanders, Alice E. Shapley, Leonardo Clarke, Michael W. Topping, Naveen Reddy, Mariska Kriek, Tucker Jones, Daniel P. Stark, Mengtao Tang

Physics and Astronomy Faculty Publications

We present ultradeep Keck/MOSFIRE rest-optical spectra of two star-forming galaxies at z = 2.18 in the COSMOS field with bright emission lines, representing more than 20 hr of total integration. The fidelity of these spectra enabled the detection of more than 20 unique emission lines for each galaxy, including the first detection of the auroral [O II]λλ7322, 7332 lines at high redshift. We use these measurements to calculate the electron temperature in the low-ionization O+ zone of the ionized interstellar medium and derive abundance ratios of O/H, N/H, and N/O using the direct method. The N/O and α/Fe abundance patterns …

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Early Results From Glass–Jwst. Xxi. Rapid Asembly Of A Galaxy At Z = 6.23 Revealed By Its C/O Abundance, Tucker Jones, Ryan L. Sanders, Yuguang Chen, Xin Wang, Takahiro Morishita, Guido Roberts-Borsani, Tommaso Treu, Alan Dressler, Emiliano Merlin, Diego Paris, Paola Santini, Pietro Bergamini, A. Henry, Erin Huntzinger, Themiya Nanayakkara, Kristan Boyett, Marusa Bradac, Gabriel B. Brammer, Antonello Calabró, Karl Glazebrook, Kathryn Grasha, Sara Mascia, Laura Pentericci, Michele Trenti, Benedetta Vulcani Jan 2023

Early Results From Glass–Jwst. Xxi. Rapid Asembly Of A Galaxy At Z = 6.23 Revealed By Its C/O Abundance, Tucker Jones, Ryan L. Sanders, Yuguang Chen, Xin Wang, Takahiro Morishita, Guido Roberts-Borsani, Tommaso Treu, Alan Dressler, Emiliano Merlin, Diego Paris, Paola Santini, Pietro Bergamini, A. Henry, Erin Huntzinger, Themiya Nanayakkara, Kristan Boyett, Marusa Bradac, Gabriel B. Brammer, Antonello Calabró, Karl Glazebrook, Kathryn Grasha, Sara Mascia, Laura Pentericci, Michele Trenti, Benedetta Vulcani

Physics and Astronomy Faculty Publications

The abundance of carbon relative to oxygen (C/O) is a promising probe of star formation history in the early universe, as the ratio changes with time due to production of these elements by different nucleosynthesis pathways. We present a measurement of log ( C / O ) = − 1.01 ± 0.12 (stat) ±0.15 (sys) in a z = 6.23 galaxy observed as part of the GLASS-JWST Early Release Science Program. Notably, we achieve good precision thanks to the detection of the rest-frame ultraviolet O iii], C iii], and C iv emission lines delivered by JWST/NIRSpec. The C/O abundance is …

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Co Emission, Molecular Gas, And Metallicity In Main-Sequence Star-Forming Galaxies At Z ∼ 2.3, Ryan L. Sanders, Alice E. Shapley, Tucker Jones, Irene Shivaei, Gergö Popping, Naveen Reddy, Romeel Davé, Sedona H. Price, Bahram Mobasher, Mariska Kriek, Alison L. Coil, Brian Siana Jan 2023

Co Emission, Molecular Gas, And Metallicity In Main-Sequence Star-Forming Galaxies At Z ∼ 2.3, Ryan L. Sanders, Alice E. Shapley, Tucker Jones, Irene Shivaei, Gergö Popping, Naveen Reddy, Romeel Davé, Sedona H. Price, Bahram Mobasher, Mariska Kriek, Alison L. Coil, Brian Siana

Physics and Astronomy Faculty Publications

We present observations of CO(3−2) in 13 main-sequence z = 2.0-2.5 star-forming galaxies at log ( M * / M ⊙ ) = 10.2 - 10.6 that span a wide range in metallicity (O/H) based on rest-optical spectroscopy. We find that L CO ( 3 − 2 ) ′ /SFR decreases with decreasing metallicity, implying that the CO luminosity per unit gas mass is lower in low-metallicity galaxies at z ∼ 2. We constrain the CO-to-H2 conversion factor (α CO) and find that α CO inversely correlates with metallicity at z ∼ 2. We derive molecular gas masses …

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