Opacities Of S-Type Stars: The Singlet B¹⊓−X¹Σ⁺, B¹⊓−A¹Δ, And C¹Σ⁺−X¹Σ⁺ Band Systems Of Zro,
2024
Old Dominion University
Opacities Of S-Type Stars: The Singlet B¹⊓−X¹Σ⁺, B¹⊓−A¹Δ, And C¹Σ⁺−X¹Σ⁺ Band Systems Of Zro, Peter F. Bernath, Manish Bhusal, Jacques Liévin
Chemistry & Biochemistry Faculty Publications
The ZrO B1Π–X1Σ+, B1Π–A1Δ, and C1Σ+–X1Σ+ band systems are important opacity sources in the near-infrared and optical spectra of S-type stars. A total of 21 rovibronic bands with v'' ≤ 7 and v' ⩽ 5 were observed and fit for the B1Π–X1Σ+ transition, five bands for the 90ZrO B1Π–A1Δ transition and one band for the 90ZrO C1Σ+–X1Σ+ transition. All band …
The A²Π–X²Σ⁺ Band System Of Yo,
2024
Old Dominion University
The A²Π–X²Σ⁺ Band System Of Yo, Peter F. Bernath, Manish Bhusal, Adam Pastorek
Chemistry & Biochemistry Faculty Publications
YO bands are conspicuous in the spectra of S stars. The laboratory spectrum of the A2Π–X2Σ+ electronic transition has been recorded with a Fourier transform spectrometer using a composite-wall hollow cathode lamp source. The A2Π–X2Σ+ transition with v ' ≤ 4 and v'' ≤ 4 has been rotationally analyzed using the modern spectral fitting program PGOPHER. Vibronic band strengths were calculated using an ab initio transition dipole moment function. A line list for the A2Π–X2Σ+ transition is provided and can be utilized in the modeling …
Ultradeep Atca Imaging Of 47 Tucanae Reveals A Central Compact Radio Source,
2024
The University of Texas Rio Grande Valley
Ultradeep Atca Imaging Of 47 Tucanae Reveals A Central Compact Radio Source, Alessandro Paduano, Arash Bahramian, James C. A. Miller-Jones, Adela Kawka, Tim J. Galvin, Liliana E. Rivera Sandoval, Sebastian Kamann, Jay Strader, Laura Chomiuk, Craig O. Heinke
Physics & Astronomy Faculty Publications
We present the results of an ultradeep radio continuum survey, containing ∼480 hr of observations, of the Galactic globular cluster 47 Tucanae with the Australia Telescope Compact Array. This comprehensive coverage of the cluster allows us to reach rms noise levels of 1.19 μJy beam−1 at 5.5 GHz, 940 nJy beam−1 at 9 GHz, and 790 nJy beam−1 in a stacked 7.25 GHz image. This is the deepest radio image of a globular cluster and the deepest image ever made with the Australia Telescope Compact Array. We identify ATCA J002405.702-720452.361, a faint (6.3 ± 1.2 μJy at 5.5 …
Agn Storm 2. Ix. Studying The Dynamics Of The Ionized Obscurer In Mrk 817 With High-Resolution X-Ray Spectroscopy,
2024
Massachusetts Institute of Technology
Agn Storm 2. Ix. Studying The Dynamics Of The Ionized Obscurer In Mrk 817 With High-Resolution X-Ray Spectroscopy, Fatima Zaidouni, Erin Kara, Peter Kosec, Missagh Mehdipour, Daniele Rogantini, Gerard A. Kriss, Ehud Behar, Jelle Kaastra, Aaron J. Barth, Edward M. Cackett, Gisella De Rosa, Yasaman Homayouni, Keith Horne, Hermine Landt, Nahum Arav, Misty C. Bentz, Michael S. Brotherton, Elena Dalla Bontà, Maryam Dehghanian, Gary Ferland, Carina Fian, Jonathan Gelbord, Michael R. Goad, Diego H. González Buitrago, Catherine J. Grier, Patrick B. Hall, Chen Hu, Dragana Ilić, Shai Kaspi, Christopher S. Kochanek, Andjelka B. Kovačević, Daniel Kynoch, Collin Lewin, John Montano, Hagai Netzer, Jack M. M. Neustadt, Christos Panagiotou, Ethan R. Partington, Rachel Plesha, Luka Č. Popović, Daniel Proga, Thaisa Storchi-Bergmann, David Sanmartim, Matthew R. Siebert, Matilde Signorini, Marianne Vestergaard, Tim Waters, Ying Zu
Physics and Astronomy Faculty Publications
We present the results of the XMM-Newton and NuSTAR observations taken as part of the ongoing, intensive multiwavelength monitoring program of the Seyfert 1 galaxy Mrk 817 by the AGN Space Telescope and Optical Reverberation Mapping 2 (AGN STORM 2) Project. The campaign revealed an unexpected and transient obscuring outflow, never before seen in this source. Of our four XMM-Newton/NuSTAR epochs, one fortuitously taken during a bright X-ray state has strong narrow absorption lines in the high-resolution grating spectra. From these absorption features, we determine that the obscurer is in fact a multiphase ionized wind with an outflow velocity of …
Agn Storm 2. Viii. Investigating The Narrow Absorption Lines In Mrk 817 Using Hst-Cos Observations,
2024
Virginia Tech
Agn Storm 2. Viii. Investigating The Narrow Absorption Lines In Mrk 817 Using Hst-Cos Observations, Maryam Dehghanian, Nahum Arav, Gerard A. Kriss, Missagh Mehdipour, Doyee Byun, Gwen Walker, Mayank Sharma, Aaron J. Barth, Misty C. Bentz, Benjamin D. Boizelle, Michael S. Brotherton, Edward M. Cackett, Elena Dalla Bontà, Gisella De Rosa, Gary Ferland, Carina Fian, Alexei V. Filippenko, Jonathan Gelbord, Michael R. Goad, Keith Horne, Yasaman Homayouni, Dragana Ilić, Michael D. Joner, Erin A. Kara, Shai Kaspi, Christopher S. Kochanek, Kirk T. Korista, Peter Kosec, Andjelka B. Kovačević, Hermine Landt, Collin Lewin, Ethan R. Partington, Luka Č. Popović, Daniel Proga, Daniele Rogantini, Matthew R. Siebert, Thaisa Storchi-Bergmann, Marianne Vestergaard, Timothy Waters, Jian-Min Wang, Fatima Zaidouni, Ying Zu
Physics and Astronomy Faculty Publications
We observed the Seyfert 1 galaxy Mrk 817 during an intensive multiwavelength reverberation mapping campaign for 16 months. Here, we examine the behavior of narrow UV absorption lines seen in the Hubble Space Telescope/ Cosmic Origins Spectrograph spectra, both during the campaign and in other epochs extending over 14 yr. We conclude that, while the narrow absorption outflow system (at −3750 km s−1 with FWHM = 177 km s−1) responds to the variations of the UV continuum as modified by the X-ray obscurer, its total column density (log NH = 19.5 - +0.13 0.61 cm−2) did not change across all …
Agn Storm 2. Vi. Mapping Temperature Fluctuations In The Accretion Disk Of Mrk 817,
2024
The Ohio State University
Agn Storm 2. Vi. Mapping Temperature Fluctuations In The Accretion Disk Of Mrk 817, Jack M. M. Neustadt, Christopher S. Kochanek, John Montano, Jonathan M. Gelbord, Aaron J. Barth, Gisella De Rosa, Gerard A. Kriss, Edward M. Cackett, Keith Horne, Erin A. Kara, Hermine Landt, Hagai Netzer, Nahum Arav, Misty C. Bentz, Elena Dalla Bontà, Maryam Dehghanian, Pu Du, Rick Edelson, Gary Ferland, Carina Fian, Travis Fischer, Michael R. Goad, Diego H. González Buitrago, Varoujan Gorjian, Catherine J. Grier, Patrick B. Hall, Yasaman Homayouni, Chen Hu, Dragana Ilić, Michael D. Joner, Jelle Kaastra, Shai Kaspi, Kirk T. Korista, Andjelka B. Kovačević, Collin Lewin, Yan-Rong Li, Ian M. Mchardy, Missagh Mehdipour, Jake A. Miller, Christos Panagiotou, Ethan Partington, Rachel Plesha, Richard W. Pogge, Luka Č. Popović, Daniel Proga, Thaisa Storchi-Bergmann, David Sanmartim, Matthew R. Siebert, Matilde Signorini
Physics and Astronomy Faculty Publications
We fit the UV/optical lightcurves of the Seyfert 1 galaxy Mrk 817 to produce maps of the accretion disk temperature fluctuations δT resolved in time and radius. The δT maps are dominated by coherent radial structures that move slowly (v = c) inward and outward, which conflicts with the idea that disk variability is driven only by reverberation. Instead, these slow-moving temperature fluctuations are likely due to variability intrinsic to the disk. We test how modifying the input lightcurves by smoothing and subtracting them changes the resulting δT maps and find that most of the temperature fluctuations exist over relatively …
Correlations Of Event Activity With Hard And Soft Processes In P + Au Collisions At √S Nn = 200 Gev At The Rhic Star Experiment,
2024
University of Kentucky
Correlations Of Event Activity With Hard And Soft Processes In P + Au Collisions At √S Nn = 200 Gev At The Rhic Star Experiment, Star Collaboration
Physics and Astronomy Faculty Publications
With the STAR experiment at the BNL Relativistic Heavy Ion Collider, we characterize √s NN = 200 GeV p + Au collisions by event activity (EA) measured within the pseudorapidity range η ∈ [−5, −3.4] in the Au-going direction and report correlations between this EA and hard- and soft-scale particle production at midrapidity (η ∈ [−1, 1]). At the soft scale, charged particle production in low-EA p + Au collisions is comparable to that in p + p collisions and increases monotonically with increasing EA. At the hard scale, we report measurements of high transverse momentum (pT ) jets in …
Collision-Energy Dependence Of Deuteron Cumulanorrelations In Au+Au Collisions At Rhicts And Proton-Deuteron C,
2024
University of Kentucky
Collision-Energy Dependence Of Deuteron Cumulanorrelations In Au+Au Collisions At Rhicts And Proton-Deuteron C, The Star Collaboration
Physics and Astronomy Faculty Publications
We report the first measurements of cumulants, up to 4𝑡ℎ order, of deuteron number distributions and proton-deuteron correlations in Au+Au collisions recorded by the STAR experiment in phase-I of Beam Energy Scan (BES) program at the Relativistic Heavy Ion Collider. Deuteron cumulants, their ratios, and proton-deuteron mixed cumulants are presented for different collision centralities covering a range of center-of-mass energy per nucleon pair √𝑠NN = 7.7 to 200 GeV. It is found that the cumulant ratios at lower collision energies favor a canonical ensemble over a grand canonical ensemble in thermal models. An anti-correlation between proton and deuteron multiplicity is …
Estimate Of Background Baseline And Upper Limit On The Chiral Magnetic Effect In Isobar Collisions At √S Nn = 200 Gev At The Bnl Relativistic Heavy Ion Collider,
2024
University of Kentucky
Estimate Of Background Baseline And Upper Limit On The Chiral Magnetic Effect In Isobar Collisions At √S Nn = 200 Gev At The Bnl Relativistic Heavy Ion Collider, Star Collaboration
Physics and Astronomy Faculty Publications
For the search of the chiral magnetic effect (CME), STAR previously presented the results from isobar collisions ( 96/44 Ru + 96/44 Ru, 96/40 Zr + 96/40 Zr) obtained through a blind analysis. The ratio of results in Ru + Ru to Zr + Zr collisions for the CME-sensitive charge-dependent azimuthal correlator (Δγ), normalized by elliptic anisotropy (v2 ), was observed to be close to but systematically larger than the inverse multiplicity ratio. The background baseline for the isobar ratio, Y = (Δγ /v2 )Ru (Δγ /v2 )Zr , is naively expected to be …
Exclusive J/Ψ, Ψ(2s), And E+E− Pair Production In Au + Au Ultraperipheral Collisions At The Bnl Relativistic Heavy Ion Collider,
2024
University of Kentucky
Exclusive J/Ψ, Ψ(2s), And E+E− Pair Production In Au + Au Ultraperipheral Collisions At The Bnl Relativistic Heavy Ion Collider, Star Collaboration
Physics and Astronomy Faculty Publications
Measurements of exclusive J/ψ, ψ (2s), and electron-positron (e+e−) pair photoproduction in Au + Au ultraperipheral collisions are reported by the STAR experiment at √sNN = 200 GeV. We report several first measurements at the BNL Relativistic Heavy Ion Collider, which are (i) J/ψ photoproduction with large momentum transfer up to 2.2 (GeV/c)2 , (ii) coherent J/ψ photoproduction associated with neutron emissions from nuclear breakup, (iii) the rapidity dependence of incoherent J/ψ photoproduction, (iv) the ψ (2s) photoproduction cross section at midrapidity, and (v) e+e− pair photoproduction up to high invariant mass of 6 GeV/c2 . For measurement (ii), the …
Jet-Hadron Correlations With Respect To The Event Plane In √S Nn = 200 Gev Au + Au Collisions In Star,
2024
University of Kentucky
Jet-Hadron Correlations With Respect To The Event Plane In √S Nn = 200 Gev Au + Au Collisions In Star, Star Collaboration
Physics and Astronomy Faculty Publications
Angular distributions of charged particles relative to jet axes are studied in √s NN = 200 GeV Au+Au collisions as a function of the jet orientation with respect to the event plane. This differential study tests the expected path-length dependence of energy loss experienced by a hard-scattered parton as it traverses the hot and dense medium formed in heavy-ion collisions. A second-order event plane is used in the analysis as an experimental estimate of the reaction plane formed by the collision impact parameter and the beam direction. Charged-particle jets with 15 < pT,jet < 20 and 20 < pT,jet < 40 GeV/c were reconstructed with the anti-kT algorithm with radius parameter setting of R = 0.4 in the 20–50% centrality bin to maximize the initial-state eccentricity of the interaction region. The reaction plane fit method is implemented to remove the flow-modulated background with better precision than prior methods. Yields and widths of jet-associated charged-hadron distributions are extracted in three angular bins between the jet axis and the event plane. The event-plane (EP) dependence is further quantified by ratios of the associated yields in different EP bins. No dependence on orientation of the jet axis with respect to the event plane is seen within the uncertainties in the kinematic regime studied. This finding is consistent with a similar experimental observation by ALICE in √s NN = 2.76 TeV Pb-Pb collision data.
Measurements Of Charged-Particle Multiplicity Dependence Of Higher-Order Net-Proton Cumulants In 𝑝+𝑝 Collisions At √𝑠 = 200 Gev From Star At Rhic,
2024
University of Kentucky
Measurements Of Charged-Particle Multiplicity Dependence Of Higher-Order Net-Proton Cumulants In 𝑝+𝑝 Collisions At √𝑠 = 200 Gev From Star At Rhic, Star Collaboration
Physics and Astronomy Faculty Publications
We report on the charged-particle multiplicity dependence of net-proton cumulant ratios up to sixth order from√𝑠 = 200 GeV 𝑝+𝑝 collisions at the Relativistic Heavy Ion Collider (RHIC). The measured ratios 𝐶4 ∕𝐶2, 𝐶5 ∕𝐶1, and 𝐶6 ∕𝐶2 decrease with increased charged-particle multiplicity and rapidity acceptance. Neither the Skellam baselines nor PYTHIA8 calculations account for the observed multiplicity dependence. In addition, the ratios 𝐶5 ∕𝐶1 and 𝐶6 ∕𝐶2 approach negative values in the highest-multiplicity events, which implies that thermalized QCD matter may be formed in 𝑝+𝑝 collisions.
Measurements Of The 𝑍0 ∕𝛾∗ Cross Section And Transverse Single Spin Asymmetry In 510 Gev 𝑝+𝑝 Collisions,
2024
University of Kentucky
Measurements Of The 𝑍0 ∕𝛾∗ Cross Section And Transverse Single Spin Asymmetry In 510 Gev 𝑝+𝑝 Collisions, The Star Collaboration
Physics and Astronomy Faculty Publications
The differential cross section for 𝑍0 production, measured as a function of the boson’s transverse momentum (𝑝T), provides important constraints on the evolution of the transverse momentum dependent parton distribution functions (TMDs). The transverse single spin asymmetry (TSSA) of the 𝑍0 is sensitive to one of the polarized TMDs, the Sivers function, which is predicted to have the opposite sign in 𝑝 + 𝑝 → 𝑊 ∕𝑍 + 𝑋 from that which enters in semi-inclusive deep inelastic scattering. In this Letter, the STAR Collaboration reports the first measurement of the 𝑍0 ∕𝛾∗ differential cross section as a function of its …
Measurement Of Flow Coefficients In High-Multiplicity P + Au, D + Au, And 3 He + Au Collisions At √S Nn = 200 Gev,
2024
University of Kentucky
Measurement Of Flow Coefficients In High-Multiplicity P + Au, D + Au, And 3 He + Au Collisions At √S Nn = 200 Gev, Star Collaboration
Physics and Astronomy Faculty Publications
Flow coefficients (v2 and v3 ) are measured in high-multiplicity p + Au, d + Au, and 3 He + Au collisions at a center-of-mass energy of √s NN = 200 GeV using the STAR detector. The measurements utilize two-particle correlations with a pseudorapidity requirement of |η| < 0.9 and a pair gap of |Δη| > 1.0. The primary focus is on analysis methods, particularly the subtraction of nonflow contributions. Four established nonflow subtraction methods are applied to determine vn, validated using the HIJING event generator. vn values are compared across the three collision systems at similar multiplicities; this comparison cancels the final-state effects and isolates the …
Reaction Plane Correlated Triangular Flow In Au+Au Collisions At √S Nn = 3 Gev,
2024
University of Kentucky
Reaction Plane Correlated Triangular Flow In Au+Au Collisions At √S Nn = 3 Gev, Star Collaboration
Physics and Astronomy Faculty Publications
We measure triangular flow relative to the reaction plane at 3 GeV center-of-mass energy in Au+Au collisions at the BNL Relativistic Heavy Ion Collider. A significant v3 signal for protons is observed, which increases for higher rapidity, higher transverse momentum, and more peripheral collisions. The triangular flow is essentially rapidity-odd with a slope at midrapidity, dv3/dy|(y=0), opposite in sign compared to the slope for directed flow. No significant v3 signal is observed for charged pions and kaons. Comparisons with models suggest that a mean field potential is required to describe these results, and that the triangular shape of the participant …
Results On Elastic Cross Sections In Proton–Proton Collisions At √𝑠 = 510 Gev With The Star Detector At Rhic,
2024
University of Kentucky
Results On Elastic Cross Sections In Proton–Proton Collisions At √𝑠 = 510 Gev With The Star Detector At Rhic, The Star Collaboration
Physics and Astronomy Faculty Publications
We report results on an elastic cross section measurement in proton–proton collisions at a center-of-mass energy√𝑠 = 510 GeV, obtained with the Roman Pot setup of the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The elastic differential cross section is measured in the four-momentum transfer squared range 0.23 ≤ −𝑡 ≤ 0.67 GeV2. This is the only measurement of the proton-proton elastic cross section in this 𝑡 range for collision energies above the Intersecting Storage Rings (ISR) and below the Large Hadron Collider (LHC) colliders. We find that a constant slope 𝐵 does not fit the data in …
Upper Limit On The Chiral Magnetic Effect In Isobar Collisions At The Relativistic Heavy-Ion Collider,
2024
University of Kentucky
Upper Limit On The Chiral Magnetic Effect In Isobar Collisions At The Relativistic Heavy-Ion Collider, Star Collaboration
Physics and Astronomy Faculty Publications
The chiral magnetic effect (CME) is a phenomenon that arises from the QCD anomaly in the presence of an external magnetic field. The experimental search for its evidence has been one of the key goals of the physics program of the Relativistic Heavy-Ion Collider. The STAR Collaboration has previously presented the results of a blind analysis of isobar collisions (96 44 Ru + 96 44 Ru, 96 40 Zr + 96 40 Zr) in the search for the CME. The isobar ratio (Y ) of CME-sensitive observable, charge separation scaled by elliptic anisotropy, is close to but systematically larger than …
Production Of Protons And Light Nuclei In Au+Au Collisions At √S Nn = 3 Gev With The Star Detector,
2024
University of Kentucky
Production Of Protons And Light Nuclei In Au+Au Collisions At √S Nn = 3 Gev With The Star Detector, Star Collaboration
Physics and Astronomy Faculty Publications
We report the systematic measurement of protons and light nuclei production in Au+Au collisions at √s NN = 3 GeV by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The transverse momentum (pT ) spectra of protons (p), deuterons (d), tritons (t), 3 He, and 4 He have been measured from midrapidity to target rapidity for different collision centralities. We present the rapidity and centrality dependence of particle yields (dN/dy), average transverse momentum (〈pT 〉), yield ratios (d/p, t/p, 3 He /p, 4 He /p), as well as the coalescence parameters (B2 , B3 ). The 4π yields …
Visible Opacities Of S-Type Stars: The D³Φ–A³Δ Band System Of Zro,
2024
Old Dominion University
Visible Opacities Of S-Type Stars: The D³Φ–A³Δ Band System Of Zro, Peter F. Bernath, Manish Bhusal, Jacques Liévin
Chemistry & Biochemistry Faculty Publications
ZrO is a well-studied metal monoxide because of its astrophysical importance in characterizing S stars. The bands of the d³Φ–a³Δ system (γ system) with v′≤4 and v" ≤ 5 are rotationally analyzed using the PGOPHER program to provide spectroscopic constants. The high-resolution ZrO emission spectrum was recorded with a Fourier transform spectrometer using a high-temperature carbon furnace source. New ab initio calculations of the transition dipole moment were carried out in order to determine the vibronic band strengths. The spectroscopic constants, along with the band strengths, are used to calculate a line list for the γ system. This line list …
Microstructural, Mineralogical, And Chemical Characterization Of The Handys Bend And Flax Creek Meteorites, Kentucky: Relevance For The Iron Meteorite Record,
2024
University of Kentucky
Microstructural, Mineralogical, And Chemical Characterization Of The Handys Bend And Flax Creek Meteorites, Kentucky: Relevance For The Iron Meteorite Record, Ethan S.L. Davis
Theses and Dissertations--Earth and Environmental Sciences
Iron meteorites remain the only material view into planetary cores. Despite their scientific relevance, iron meteorites are relatively rare. In June 2021 and March 2022, the Kentucky Geological Survey received requests to identify two metallic specimens discovered in central Kentucky. The specimens were given the provisional names Handys Bend (3175.2 g) and Flax Creek (286.2 g). The goal of this project is to confirm meteoritic origin, characterize their structures and chemistry, assign genetic classifications, and examine potential relations to previous discoveries. Petrography was conducted using scanning electron microscopy. Mineral phases were examined using X-Ray diffraction crystallography. Chemical compositions were determined …
