Physics Commons^™

Taylor Dispersion In Variable-Density, Variable-Viscosity Pulsatile Flows, Prabakaran Rajamanickam, Adam D. Weiss

Progress in Scale Modeling, an International Journal

The phenomenon of Taylor or shear-induced dispersion of a non-passive scalar field in a pulsatile pipe flow is investigated, accounting for the scalar field's influence on fluid density and transport coefficients. By employing multiple scale analysis, an effective one-dimensional, unsteady mixing problem for the scalar field is obtained, which includes the diffusion coefficient for shear-induced dispersion. The resulting governing equations are applicable to a range of scalar transport problems in pulsatile pipe flows.

A Comparison Of Time-Dependent Cloudy Astrophysical Code Simulations With Experimental X-Ray Spectra From Kev Laser-Generated Argon Plasmas, N. Rathee, F. P. Keenan, R. J. R. Williams, Gary Ferland, S. J. Rose, S. White, D. Riley

Physics and Astronomy Faculty Publications

We have generated strongly photoionized Ar plasmas in experiments designed to use primarily X-ray l-shell line emission generated from Ag foils irradiated by the VULCAN high-power laser at the UK Central Laser Facility. The principle of the experiment is that use of line emission rather than the usual sub-keV quasi-blackbody source allows keV radiation to play a more dominant role compared to softer X-rays and thus mimic the effect of a blackbody with a higher effective spectral temperature. Our aim is to reproduce in the laboratory the extreme photoionization conditions found in accretion-powered astrophysical sources. In this paper, we compare …

Accelerator Based Fusion Reactor With Magnetic Mirror, Keh-Fei Liu

Physics and Astronomy Faculty Publications

We consider an implementation of the novel accelerator-based fusion reactor scheme using a setup in which ion and electron beams are injected into the end openings of an axisymmetric magnetic mirror. While the magnetic mirror ensures transverse confinement of the plasma, the injected beams contribute to axial confinement, thereby extending the overall plasma lifetime. The ion beam energy is initially set above the resonance region of the fusion reactions, allowing fusion to occur both via resonance and thermal mechanisms as the beam slows down to the plasma temperature. Beam energy loss (stopping power) contributes to plasma heating, offsetting radiative losses …

Dynamical Phases Of Higher Dimensional Floquet Cfts, Diptarka Das, Sumit R. Das, Arnab Kundu, Krishnendu Sengupta

Physics and Astronomy Faculty Publications

This paper investigates the dynamical phases of Floquet Conformal Field Theories (CFTs) in space-time dimensions greater than two. Building upon our previous work which introduced quaternionic representations for studying Floquet dynamics in higher-dimensional CFTs, we now explore more general square pulse drive protocols that go beyond a single SU(1,1) subgroup. We demonstrate that, for multi-step drive protocols, the system exhibits distinct dynamical phases characterized by the nature of the eigenvalues of the quaternionic matrix representing time evolution in a single cycle, leading to different stroboscopic responses. Our analysis establishes a fundamental geometric interpretation where these dynamical phases directly correspond to …

Emission-Line Diagnostics At Z ≳ 2: A Probe Of The Ionizing Spectrum And Α-Enhancement Beyond Cosmic Noon, Leonardo Clarke, Natalie Lam, Alice E. Shapley, Michael W. Topping, Gabriel B. Brammer, Ryan L. Sanders, Naveen Reddy, Shreya Karthikeyan

Physics and Astronomy Faculty Publications

We analyze several key rest-optical emission-line ratios in a sample of 828 galaxies as well as composite spectra from JADES DR3 in the range 1.4 <  z <  7. These emission-line ratios include: [O iii]λ5008/Hβ, [N ii]λ6585/Hα, [S ii]λλ6718, 6733/Hα, [O i]λ6302/Hα, O32, R23, Ne3O2, and RO2Ne3. We find evidence for a harder ionizing spectrum at z ∼ 3.5 compared to z ∼ 2 at fixed gas-phase metallicity, resulting in a pronounced shift in the star-forming galaxy locus on the [N ii]/Hα Baldwin-Phillips-Terlevich (BPT) diagram and the O32 versus R23 diagram. At …

A Chandra View Of Spt-Cl J0217–5014: A Massive Galaxy Cluster At A Cosmic Intersection At Z = 0.53, Dan Hu, Shida Fan, Zhongsheng Yuan, Junjie Mao, Norbert Werner, Yuanyuan Su, François Mernier, Yuanyuan Zhao, Liyi Gu, Haiguang Xu

Physics and Astronomy Faculty Publications

Context. Galaxy clusters trace the densest regions of the cosmic web and are crucial laboratories for studying the thermodynamic and chemical evolution of the intracluster medium (ICM). The massive galaxy cluster SPT-CL J0217−5014 (z ∼ 0.53; M₅₀₀ ∼ 3 × 10¹⁴ M_⊙) is one of the Swift X-Ray Telescope serendipitous galaxy clusters with the highest reported Fe abundance (∼1.3 ± 0.4 Z_⊙ within ∼ 1_.^′7) and a potentially disturbed morphology.

Aims. SPT-CL J0217−5014 presents an intriguing opportunity to investigate ICM chemical enrichment and cool-core survival. With this study, we aim to …

A Uniform Analysis Of Gas-Phase Metallicity Evolution With 1–3 Gyr Time Sampling Over The Past 12 Gyr, Shweta Jain, Ryan L. Sanders, Ali Ahmad Khostova, Tucker Jones, Alice E. Shapley, Naveen Reddy, Alex M. Garcia, Paul Torrey, Alison L. Coil

Physics and Astronomy Faculty Publications

We present a systematic investigation of the evolution of the mass–metallicity relation (MZR) and fundamental metallicity relation (FMR) using uniform metallicity diagnostics across redshifts z ∼ 0 to z ∼ 3.3. We present new Keck/Deep Imaging Multi-Object Spectrograph measurements of the [O II]λλ3726, 3729 emission line doublet for star-forming galaxies at z ∼ 1.5 with existing measurements of redder rest-optical lines from the MOSFIRE Deep Evolution Field survey. These new observations enable uniform estimation of the gas-phase oxygen abundance using ratios of the [O II], Hβ, and [O III] lines for mass-binned samples of star-forming galaxies …

Energy Levels Of Multiscale Bound States From Qed Energy-Momentum Trace, Michael I. Eides, Vladimir A. Yerokhin

Physics and Astronomy Faculty Publications

Energy levels of quantum electrodynamics (QED) bound states, which depend on a number of independent mass parameters, can be calculated as matrix elements of the QED energy-momentum tensor trace. As an example of such system we consider muonic hydrogen. The leading one-loop corrections to its energy levels depend on the electron and muon masses. These corrections are calculated as matrix elements of the energy-momentum tensor trace. Respective one-loop trace diagrams are different from the standard Lamb shift diagrams. We explain analytically and diagrammatically why two different sets of diagrams lead to the same results. Similar relationships should also hold beyond …

Fe Xviii–Xxiv Kβ Inner-Shell Absorption Lines In The X-Ray Spectra Of Neutron Star And Black Hole Binaries With Xrism, Masahiro Tsujimoto, Daiki Miura, Hiroya Yamaguchi, Ehud Behar, Chris Done, María Díaz Trigo, Chamani M. Gunasekera, Peter A. M. Van Hoof, Stefano Bianchi, Maryam Dehghanian, Gary J. Ferland

Physics and Astronomy Faculty Publications

The advent of the X-ray microcalorimeter spectrometer Resolve onboard the XRISM space telescope opened a new era for high-resolution X-ray spectroscopy of astrophysical plasmas. Many spectral features were newly detected, including the Kα and Kβ inner-shell transition lines of mildly ionized (F- to Li-like) Fe at 6–8 keV in the spectra of X-ray binaries and active galactic nuclei. The widely used atomic databases contain information on the Kα but not Kβ lines of these ions. We conducted the atomic structure calculation using FAC to derive the Fe Kα and Kβ lines and verified the …

Regulating Galaxy Growth: Ionized Gas Conditions, Star Formation Histories, And Environmental Effects, Shweta Jain

University of Kentucky Doctoral Dissertations

Understanding galaxy formation and evolution requires tracing how baryons cycle between stars, gas, and the interstellar medium (ISM) across cosmic time. The efficiency of star formation, the buildup of metals, and the regulation of gas inflows and outflows are governed by evolving physical conditions within galaxies and their environments. My thesis investigates how the ionized ISM, star formation histories, and environmental processes have shaped galaxy evolution over the past ∼ 12 Gyr. The primary focus of this work is the evolution of the physical conditions of ionized gas in galaxies, including gas-phase metallicity and ionization state. Using new and archival …

Energy Dependence Of Polarized Γγ → E+E− In Peripheral Au + Au Collisions At √Snn = 54.4 And 200 Gev With The Star Experiment At Rhic, Star Collaboration

Physics and Astronomy Faculty Publications

We report the differential yields at mid-rapidity of the Breit-Wheeler process (γ γ → e+e−) in peripheral Au + Au collisions at √s NN = 54.4 and 200 GeV with the STAR experiment at the Relativistic Heavy Ion Collider (RHIC), as a function of energy √s NN , e+e− transverse momentum pT , p2 T , invariant mass Mee, and azimuthal angle. In the invariant mass range of 0.4 < Mee < 2.6 GeV/c2 at low transverse momentum (pT < 0.15 GeV/c), the yields increase while the pair √〈p2 T〉 decreases with increasing √s NN , a feature that is correctly predicted by the QED calculation. The energy dependencies of the measured quantities are sensitive to the nuclear form factor, infrared divergence and photon polarization. The data are compiled and used to extract the charge radius of the Au nucleus.

Measurement Of Two-Point Energy Correlators Within Jets In P+P Collisions At Sqrt[S]=200  Gev, Star Collaboration

Physics and Astronomy Faculty Publications

Hard-scattered partons ejected from high-energy proton-proton collisions undergo parton shower and hadronization, resulting in collimated collections of particles that are clustered into jets. A substructure observable that highlights the transition between the perturbative and nonperturbative regimes of jet evolution in terms of the angle between two particles is the two-point energy correlator (EEC). In this Letter, the first measurement of the EEC at RHIC is presented, using data taken from 200 GeV p þ p collisions by the STAR experiment. The EEC is measured both for all the pairs of particles in jets and separately for pairs with like and …

Design Of The Ecce Detector For The Electron Ion Collider, J. K. Adkins

Physics and Astronomy Faculty Publications

The EIC Comprehensive Chromodynamics Experiment (ECCE) detector has been designed to address the full scope of the proposed Electron Ion Collider (EIC) physics program as presented by the National Academy of Science and provide a deeper understanding of the quark–gluon structure of matter. To accomplish this, the ECCE detector offers nearly acceptance and energy coverage along with excellent tracking and particle identification. The ECCE detector was designed to be built within the budget envelope set out by the EIC project while simultaneously managing cost and schedule risks. This detector concept has been selected to be the basis for the EIC …

Laser–Assisted Free–Free (Laff) Electron Scattering: An Elastic Angular Distribution In Argon And The Use Of A Novel Pulsed-Laser Multipass System In Laff Experiments, Charles M. Weaver

Theses and Dissertations--Physics and Astronomy

Laser–assisted free–free experiments investigate the emission or absorption of photons when an electron scatters from an atom in the presence of a laser field.

We measured the relative differential cross sections for 350 eV electrons scattered by an argon target in the presence of 1.17 eV photons from a Nd:YAG laser. The angular distribution for elastically scattered 350 eV electrons was measured over scattering angles from 4◦ to 80◦. This distribution exhibits a pronounced maximum near 47◦ and is symmetric about this angle, as predicted by a Kroll–Watson approximation (KWA) calculation for the experimental kinematics. These measurements directly test a …

Light Nuclei Femtoscopy And Baryon Interactions In 3 Gev Au+Au Collisions At Rhic, The Star Collaboration

Physics and Astronomy Faculty Publications

We report the measurements of proton-deuteron (𝑝-𝑑) and deuteron-deuteron (𝑑-𝑑) correlation functions in Au+Au collisions at √𝑠NN = 3 GeV using fixed-target mode with the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). For the first time, the source size (𝑅 𝐺), scattering length (𝑓0), and effective range (𝑑0) are extracted from the measured correlation functions with a simultaneous fit. The spin-averaged 𝑓0 for 𝑝-𝑑 and 𝑑-𝑑 interactions are determined to be -5.28 ± 0.11(stat.) ± 0.82(syst.) fm and -2.62 ± 0.02(stat.) ± 0.24(syst.) fm, respectively. The measured 𝑝-𝑑 interaction is consistent with theoretical calculations and low- energy scattering experiment …

Electric-Charge-Dependent Directed Flow Splitting Of Produced Quarks In Au+Au Collisions, The Star Collaboration

Physics and Astronomy Faculty Publications

We report directed flow (𝑣1) of multistrange baryons (Ξ and Ω) and improved 𝑣1 data for 𝐾−, ̄ 𝑝, ̄ Λ and 𝜙 in Au+Au collisions at √𝑠NN =27 and 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). We focus on particles whose constituent quarks are not transported from the incoming nuclei but instead are produced in the collisions. At intermediate impact parameters, we examine quark coalescence behavior for particle combinations with identical quark content, and search for any departure from this behavior (“splitting”) for combinations having non-identical quark content. Under the assumption of quark …

Measurement Of Directed Flow In Au+Au Collisions At √Snn = 19.6 And 27 Gev With The Star Event Plane Detector, Star Collaboration

Physics and Astronomy Faculty Publications

In heavy-ion collision experiments, the global collectivity of final-state particles can be quantified by anisotropic flow coefficients (vn). The first-order flow coefficient, also referred to as the directed flow (v1 ), describes the collective sideward motion of produced particles and nuclear fragments in heavy-ion collisions. It carries information on the very early stage of the collision, especially at large pseudorapidity (η), where it is believed to be generated during the nuclear passage time. Directed flow therefore probes the onset of bulk collective dynamics during thermalization, providing valuable experimental guidance to models of the pre-equilibrium stage. In 2018, the Event Plane …

Simulations Of Electron Detection Systematic Errors For A Ucna+ Experiment, Rashika Gupta

Theses and Dissertations--Physics and Astronomy

The Ultracold Neutron Asymmetry+ (UCNA+) experiment at the Los Alamos Neu- tron Science Center (LANSCE) Ultracold Neutron source is an upgrade of the UCNA experiment, designed to measure the neutron beta decay asymmetry parameter, A 0 , with a precision of less than 0.2% using polarized ultracold neutrons (UCN). Neutron beta decay is governed by the weak interaction, and a precise measurement of A 0 provides a determination of the axial-vector to vector coupling ratio, λ = gA /gV . When combined with a measurement of the neutron lifetime, this allows the extraction of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element Vud …

Optimizing External Radioactive Calibration Source Strength To Maximize The Livetime Of The Nexo Detector, Thakur P. Bhatta

Theses and Dissertations--Physics and Astronomy

The proposed next Enriched Xenon Observatory (nEXO) experiment aims to detect neutrinoless double beta decay in 136Xe, a rare process with profound implications for particle physics and our understanding of the neutrino. Achieving the required sensitivity demands ultra-low background conditions, making both material radiop urity screening and precise detector calibration essential. This dissertation addresses two key calibration challenges in preparation for nEXO. First, I investigated discrepancies in calibration efficiency measurements of the high-purity germanium (HPGe) detector named as GeIV located 4850 feet under ground at the Sanford Underground Research Facility, Lead, SD. The root cause for the discrepancy was found …

Quantum Hall Phases In Monolayer Graphene, Jincheng An

Theses and Dissertations--Physics and Astronomy

In the presence of a perpendicular magnetic field, monolayer graphene at and near charge neutrality forms a quantum Hall ferromagnet—a correlated electronic state where the interplay of interactions, spin, and valley degrees of freedom leads to spontaneous symmetry breaking. While the dominant Coulomb interaction has $SU(4)$ symmetry, the ground state is ultimately determined by subdominant terms: residual lattice-scale anisotropic interactions, Zeeman, and sublattice couplings. Relaxing the ultra-short-range limit of anisotropic interactions unveils diverse symmetry-breaking phases in both integer and fractional quantum Hall regimes. Haldane pseudopotentials, which quantify interactions between particle pairs with fixed relative angular momentum, provide a readily parameterizable …

Interplay Between Computational Techniques And Quantum Theory: Advancing Quantum Chaos And Quantum Error Correction, Refaat Ismail

Theses and Dissertations--Physics and Astronomy

This dissertation investigates computational techniques addressing critical problems arising within quantum chaos and quantum error correction (QEC). First, we investigate quantum dynamics via the Lanczos algorithm, establishing how its computational features — branching patterns, convergence, and complexity saturation — relate to physical properties like spectral statistics and operator matrix elements. We derive a formula connecting Lanczos coefficients to spectral densities for two-branched Lanczos sequences, revealing how branching patterns encode level repulsion—a hallmark of quantum chaos. Furthermore, we develop an analytic framework predicting Krylov complexity saturation from static system properties alone. Specifically, we decompose the saturation value into a spectral density-dependent …

Structural And Physical Properties Of Solid State Materials: Cegage, Cssni3, And Yb2Si2-XGeXAl, Liam J. Scanlon

Theses and Dissertations--Physics and Astronomy

We present studies of three independent solid state materials: CeGaGe, CsSnI₃, and Yb₂Si_2-xGe_xAl.

CeGaGe is a magnetic candidate Weyl semimetal. Magnetic Weyl semimetals have possible technological applications due to their electronically conducting bulk states, magnetic states, and topologically protected surface states. We grew single crystals of CeGaGe using the zone-refinement method and flux-growth method. With single crystal X-ray and neutron diffraction, we found that zone-refined CeGaGe crystallizes with the I4₁md symmetry (space group 109). With single crystal X-ray diffraction, we found that flux-grown samples of CeGaGe have the …

Effects Of A-Site Cation Structure And B-Site Metal On Optical And Electronic Properties Of 2d Ruddlesden-Popper Phase Tin-Based Hybrid Perovskites, Henry Pruett

Theses and Dissertations--Chemistry

Organic metal halide perovskites (HPs) are attractive materials for a variety of electronic applications due to their low cost, tunable band gaps, excellent charge transport properties, and high photoluminescence efficiency. As such, HPs are being investigated for use in solar cells, photodetectors, X-ray detectors, light emitting diodes, field effect transistors, lasers, resistive random-access memory, etc. Currently the most popular metal used in HPs is lead, but the use of lead comes with the potential for heavy metal exposure. Tin-based perovskites offer a less hazardous alternative, but their optoelectronic properties lag behind those of lead and less work has been done …

Dual Light Emission Of Cssni3-Based Powders Synthesized Via A Mechanochemical Process, Xuan Huang, Xiaobing Tang, Xiyu Wen, Yuebin Charles Lu, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Lead toxicity has hindered the wide applications of lead halide perovskites in optoelec- tronics and bioimaging. A significant amount of effort has been made to synthesize lead-free halide perovskites as alternatives to lead halide perovskites. In this work, we demonstrate the feasibility of synthesizing CsSnI3-based powders mechanochemically with dual light emissions under ambi- ent conditions from CsI and SnI2 powders. The formed CsSnI3-based powders are divided into CsSnI3-dominated powders and CsSnI3-contained powders. Under the excitation of ultraviolet light of 365 nm in wavelength, the CsSnI3-dominated powders emit green light with a wavelength centered at 540 nm, and the CsSnI3-contained powders …

Diffuse Reflectance Spectroscopy For Optical Characterizations Of Orthotopic Head And Neck Cancer Models In Vivo, Pranto Soumik Saha, Jing Yan, Caigang Zhu

Markey Cancer Center Faculty Publications

We demonstrated an easy-to-build, portable diffuse reflectance spectroscopy device along with a Monte Carlo inverse model to quantify tissue absorption and scattering-based parameters of orthotopic head and neck cancer models in vivo. Both tissue-mimicking phantom studies and animal studies were conducted to verify the optical spectroscopy system and Monte Carlo inverse model for the accurate extraction of tissue optical properties. For the first time, we reported the tissue absorption and scattering coefficients of mouse normal tongue tissues and tongue tumor tissues. Our in vivo animal studies showed reduced total hemoglobin concentration, lower tissue vascular oxygen saturation, and increased tissue scattering …

Shorting At Long Duration: Impact Of Extended Discharge Capacity On Battery Solid Electrolytes, Ryan C. Hill, Amanda S. Peretti, Leo J. Small, Erik D. Spoerke, Yang-Tse Cheng

Chemical and Materials Engineering Faculty Publications

Long-duration energy storage (LDES) is critical to a stable, resilient, and decarbonized electric grid. While batteries are emerging as important LDES devices, extended, high-power discharges necessary for cost-competitive LDES present new materials challenges. Focusing on a new generation of low-temperature molten sodium batteries, we explore here unique phenomena related to long-duration discharge through a well-known solid electrolyte, NaSICON. Specifically, molten sodium symmetric cells at 110 ° C were cycled at 0.1 A cm−2 for 1–23 h discharges. Longer discharges led to unstable overpotentials, reduced resistances, and decreased electrolyte strength, caused by massive sodium penetration not observed in shorter duration discharges. …

Myeloid-Derived Suppressor Cell Mitochondrial Fitness Governs Chemotherapeutic Efficacy In Hematologic Malignancies, Saeed Daneshmandi, Jee Eun Choi, Qi Yan, Cameron R. Macdonald, Manu Pandey, Mounika Goruganthu, Nathan Roberts, Prashant K. Singh, Richard M. Higashi, Andrew N. Lane, Teresa W-M Fan, Jianmin Wang, Philip L. Mccarthy, Elizabeth A. Repasky, Hemn Mohammadpour

Markey Cancer Center Faculty Publications

Myeloid derived suppressor cells (MDSCs) are key regulators of immune responses and correlate with poor outcomes in hematologic malignancies. Here, we identify that MDSC mitochondrial fitness controls the efficacy of doxorubicin chemotherapy in a preclinical lymphoma model. Mechanistically, we show that triggering STAT3 signaling via β2-adrenergic receptor (β2-AR) activation leads to improved MDSC function through metabolic reprogram- ing, marked by sustained mitochondrial respiration and higher ATP generation which reduces AMPK signaling, altering energy metabolism. Furthermore, induced STAT3 signaling in MDSCs enhances glutamine consumption via the TCA cycle. Metabolized glutamine generates itaconate which downregulates mitochondrial reactive oxygen species via regulation of …

Imaging Shapes Of Atomic Nuclei In High-Energy Nuclear Collisions, Star Collaboration

Physics and Astronomy Faculty Publications

Atomic nuclei are self-organized, many-body quantum systems bound by strong nuclear forces within femtometre-scale space. These complex systems manifest a variety of shapes1–3 , traditionally explored using non-invasive spectroscopic techniques at low energies4,5 . However, at these energies, their instantaneous shapes are obscured by long-timescale quantum fluctuations, making direct observation challenging. Here we introduce the collective-flow-assisted nuclear shape-imaging method, which images the nuclear global shape by colliding them at ultrarelativistic speeds and analysing the collective response of outgoing debris. This technique captures a collision-specific snapshot of the spatial matter distribution within the nuclei, which, through the hydrodynamic expansion, imprints patterns …

Agn Storm 2. Vii. A Frequency-Resolved Map Of The Accretion Disk In Mrk 817: Simultaneous X-Ray Reverberation And Uvoir Disk Reprocessing Time Lags, Collin Lewin, Erin Kara, Aaron J. Barth, Edward M. Cackett, Gisella De Rosa, Yasaman Homayouni, Keith Horne, Gerard A. Kriss, Hermine Landt, Jonathan Gelbord, John Montano, Nahum Arav, Misty C. Bentz, Benjamin D. Boizelle, Elena Dalla Bontà, Michael S. Brotherton, Maryam Dehghanian, Gary Ferland, Carina Fian, Michael R. Goad, Juan V. Hernández Santisteban, Dragana Ilić, Jelle Kaastra, Shai Kaspi, Kirk T. Korista, Peter Kosec, Andjelka B. Kovačević, Missagh Mehdipour, Jake A. Miller, Hagai Netzer, Jack M. M. Neustadt, Christos Panagiotou, Ethan R. Partington, Luka Č. Popović, David Sanmartim, Marianne Vestergaard, Martin J. Ward, Fatima Zaidouni

Physics and Astronomy Faculty Publications

X-ray reverberation mapping is a powerful technique for probing the innermost accretion disk, whereas continuum reverberation mapping in the UV, optical, and infrared (UVOIR) reveals reprocessing by the rest of the accretion disk and broad-line region (BLR). We present the time lags of Mrk 817 as a function of temporal frequency measured from 14 months of high-cadence monitoring from Swift and ground-based telescopes, in addition to an XMM-Newton observation, as part of the AGN STORM 2 campaign. The XMM-Newton lags reveal the first detection of a soft lag in this source, consistent with reverberation from the innermost accretion flow. These …

Agn Storm 2. V. Anomalous Behavior Of The C Iv Light Curve Of Mrk 817, Y. Homayouni, Gerard A. Kriss, Gisella De Rosa, Rachel Plesha, Edward M. Cackett, Michael R. Goad, Kirk Korista, Keith Horne, Travis Fischer, Tim Waters, Aaron J. Barth, Erin A. Kara, Hermine Landt, Nahum Arav, Benjamin D. Boizelle, Misty C. Bentz, Michael S. Brotherton, Doron Chelouche, Elena Dalla Bontà, Maryam Dehghanian, Pu Du, Gary Ferland, Carina Fian, Jonathan Gelbord, Catherine J. Grier, Patrick B. Hall, Chen Hu, Dragana Ilić, Michael D. Joner, Jelle Kaastra, Shai Kaspi, Andjelka B. Kovačević, Daniel Kynoch, Yan-Rong Li, Missagh Mehdipour, Jake A. Miller, Jake Mitchell, John Montano, Hagai Netzer, Jack M. M. Neustadt, Ethan Partington, Luka Č. Popović, Daniel Proga, Thaisa Storchi-Bergmann, David Sanmartim, Matthew R. Siebert, Tommaso Treu, Marianne Vestergaard, Jian-Min Wang, Martin J. Ward, Fatima Zaidouni, Ying Zu

Physics and Astronomy Faculty Publications

An intensive reverberation mapping campaign of the Seyfert 1 galaxy Mrk 817 using the Cosmic Origins Spectrograph on the Hubble Space Telescope revealed significant variations in the response of broad UV emission lines to fluctuations in the continuum emission. The response of the prominent UV emission lines changes over an ∼60 day duration, resulting in distinctly different time lags in the various segments of the light curve over the 14 month observing campaign. One-dimensional echo-mapping models fit these variations if a slowly varying background is included for each emission line. These variations are more evident in the C IV light …