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- Active galaxies (5)
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- Galaxy abundances (4)
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- Star formation (4)
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- H II regions (3)
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- STAR Collaboration (2)
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- 13th Data Release (1)
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Articles 1 - 30 of 35
Full-Text Articles in Physical Sciences and Mathematics
Spin-Valley Coherent Phases Of The V = 0 Quantum Hall State In Bilayer Graphene, Ganpathy Murthy, Efrat Shimshoni, H. A. Fertig
Spin-Valley Coherent Phases Of The V = 0 Quantum Hall State In Bilayer Graphene, Ganpathy Murthy, Efrat Shimshoni, H. A. Fertig
Physics and Astronomy Faculty Publications
Bilayer graphene (BLG) offers a rich platform for broken-symmetry states stabilized by interactions. In this work, we study the phase diagram of BLG in the quantum Hall regime at filling factor ν = 0 within the Hartree-Fock approximation. In the simplest noninteracting situation, this system has eight (nearly) degenerate Landau levels near the Fermi energy, characterized by spin, valley, and orbital quantum numbers. We incorporate in our study two effects not previously considered: (i) the nonperturbative effect of trigonal warping in the single-particle Hamiltonian, and (ii) short-range SU(4) symmetry-breaking interactions that distinguish the energetics of the orbitals. We find within …
Sdss-Iv Manga: Probing The Kinematic Morphology–Density Relation Of Early-Type Galaxies With Manga, J. E. Greene, A. Leauthaud, E. Emsellem, D. Goddard, J. Ge, B. H. Andrews, J. Brinkman, J. R. Brownstein, J. Greco, D. Law, Y. -T. Lin, K. L. Masters, M. Merrifield, S. More, N. Okabe, D. P. Schneider, D. Thomas, D. A. Wake, Renbin Yan, N. Drory
Sdss-Iv Manga: Probing The Kinematic Morphology–Density Relation Of Early-Type Galaxies With Manga, J. E. Greene, A. Leauthaud, E. Emsellem, D. Goddard, J. Ge, B. H. Andrews, J. Brinkman, J. R. Brownstein, J. Greco, D. Law, Y. -T. Lin, K. L. Masters, M. Merrifield, S. More, N. Okabe, D. P. Schneider, D. Thomas, D. A. Wake, Renbin Yan, N. Drory
Physics and Astronomy Faculty Publications
The "kinematic" morphology–density relation for early-type galaxies posits that those galaxies with low angular momentum are preferentially found in the highest-density regions of the universe. We use a large sample of galaxy groups with halo masses 1012.5 < Mhalo < 1014.5 h-1 M⊙ observed with the Mapping Nearby Galaxies at APO (MaNGA) survey to examine whether there is a correlation between local environment and rotational support that is independent of stellar mass. We find no compelling evidence for a relationship between the angular momentum content of early-type galaxies and either local overdensity or radial position within the group …
Sdss-Iv Manga: Spatially Resolved Star Formation Main Sequence And Li(N)Er Sequence, B. C. Hsieh, Lihwai Lin, J. H. Lin, H. A. Pan, C. H. Hsu, S. F. Sánchez, M. Cano-Díaz, Kai Zhang, Renbin Yan, J. K. Barrera-Ballesteros, M. Boquien, R. Riffel, J. Brownstein, I. Cruz-González, A. Hagen, H. Ibarra, K. Pan, D. Bizyaev, D. Oravetz, A. Simmons
Sdss-Iv Manga: Spatially Resolved Star Formation Main Sequence And Li(N)Er Sequence, B. C. Hsieh, Lihwai Lin, J. H. Lin, H. A. Pan, C. H. Hsu, S. F. Sánchez, M. Cano-Díaz, Kai Zhang, Renbin Yan, J. K. Barrera-Ballesteros, M. Boquien, R. Riffel, J. Brownstein, I. Cruz-González, A. Hagen, H. Ibarra, K. Pan, D. Bizyaev, D. Oravetz, A. Simmons
Physics and Astronomy Faculty Publications
We present our study on the spatially resolved Hα and M* relation for 536 star-forming and 424 quiescent galaxies taken from the MaNGA survey. We show that the star formation rate surface density (ΣSFR), derived based on the Hα emissions, is strongly correlated with the M* surface density (Σ*) on kiloparsec scales for star-forming galaxies and can be directly connected to the global star-forming sequence. This suggests that the global main sequence may be a consequence of a more fundamental relation on small scales. On the other hand, our result suggests that …
The 13th Data Release Of The Sloan Digital Sky Survey: First Spectroscopic Data From The Sdss-Iv Survey Mapping Nearby Galaxies At Apache Point Observatory, Franco D. Albareti, Carlos Allende Prieto, Andres Almeida, Friedrich Anders, Scott Anderson, Brett H. Andrews, Alfonso Aragón-Salamanca, Maria Argudo-Fernández, Eric Armengaud, Eric Aubourg, Vladimir Avila-Reese, Carles Badenes, Stephen Bailey, Beatriz Barbuy, Kat Barger, Jorge Barrera-Ballesteros, Curtis Bartosz, Sarbani Basu, Dominic Bates, Giuseppina Battaglia, Falk Baumgarten, Julien Baur, Julian Bautista, Timothy C. Beers, Francesco Belfiore, Matthew Bershady, Sara Bertran De Lis, Jonathan C. Bird, Dmitry Bizyaev, Guillermo A. Blanc, Renbin Yan, Kai Zhang
The 13th Data Release Of The Sloan Digital Sky Survey: First Spectroscopic Data From The Sdss-Iv Survey Mapping Nearby Galaxies At Apache Point Observatory, Franco D. Albareti, Carlos Allende Prieto, Andres Almeida, Friedrich Anders, Scott Anderson, Brett H. Andrews, Alfonso Aragón-Salamanca, Maria Argudo-Fernández, Eric Armengaud, Eric Aubourg, Vladimir Avila-Reese, Carles Badenes, Stephen Bailey, Beatriz Barbuy, Kat Barger, Jorge Barrera-Ballesteros, Curtis Bartosz, Sarbani Basu, Dominic Bates, Giuseppina Battaglia, Falk Baumgarten, Julien Baur, Julian Bautista, Timothy C. Beers, Francesco Belfiore, Matthew Bershady, Sara Bertran De Lis, Jonathan C. Bird, Dmitry Bizyaev, Guillermo A. Blanc, Renbin Yan, Kai Zhang
Physics and Astronomy Faculty Publications
The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in 2014 July. It pursues three core programs: the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2), Mapping Nearby Galaxies at APO (MaNGA), and the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). As well as its core program, eBOSS contains two major subprograms: the Time Domain Spectroscopic Survey (TDSS) and the SPectroscopic IDentification of ERosita Sources (SPIDERS). This paper describes the first data release from SDSS-IV, Data Release 13 (DR13). DR13 makes publicly available the first 1390 spatially resolved integral field unit observations of nearby galaxies from MaNGA. It …
Biases In Metallicity Measurements From Global Galaxy Spectra: The Effects Of Flux Weighting And Diffuse Ionized Gas Contamination, Ryan L. L. Sanders, Alice E. Shapley, Kai Zhang, Renbin Yan
Biases In Metallicity Measurements From Global Galaxy Spectra: The Effects Of Flux Weighting And Diffuse Ionized Gas Contamination, Ryan L. L. Sanders, Alice E. Shapley, Kai Zhang, Renbin Yan
Physics and Astronomy Faculty Publications
Galaxy metallicity scaling relations provide a powerful tool for understanding galaxy evolution, but obtaining unbiased global galaxy gas-phase oxygen abundances requires proper treatment of the various line-emitting sources within spectroscopic apertures. We present a model framework that treats galaxies as ensembles of H II and diffuse ionized gas (DIG) regions of varying metallicities. These models are based upon empirical relations between line ratios and electron temperature for H II regions, and DIG strong-line ratio relations from SDSS-IV MaNGA IFU data. Flux-weighting effects and DIG contamination can significantly affect properties inferred from global galaxy spectra, biasing metallicity estimates by more than …
An Exactly Solvable Quench Protocol For Integrable Spin Models, Diptarka Das, Sumit R. Das, Damián A. Galante, Robert C. Myers, Krishnendu Sengupta
An Exactly Solvable Quench Protocol For Integrable Spin Models, Diptarka Das, Sumit R. Das, Damián A. Galante, Robert C. Myers, Krishnendu Sengupta
Physics and Astronomy Faculty Publications
Quantum quenches in continuum field theory across critical points are known to display different scaling behaviours in different regimes of the quench rate. We extend these results to integrable lattice models such as the transverse field Ising model on a one-dimensional chain and the Kitaev model on a two-dimensional honeycomb lattice using a nonlinear quench protocol which allows for exact analytical solutions of the dynamics. Our quench protocol starts with a finite mass gap at early times and crosses a critical point or a critical region, and we study the behaviour of one point functions of the quenched operator at …
Evolution Of Galactic Outflows At Z ~ 0–2 Revealed With Sdss, Deep2, And Keck Spectra, Yuma Sugahara, Masami Ouchi, Lihwai Lin, Crystal L. Martin, Yoshiaki Ono, Yuichi Harikane, Takatoshi Shibuya, Renbin Yan
Evolution Of Galactic Outflows At Z ~ 0–2 Revealed With Sdss, Deep2, And Keck Spectra, Yuma Sugahara, Masami Ouchi, Lihwai Lin, Crystal L. Martin, Yoshiaki Ono, Yuichi Harikane, Takatoshi Shibuya, Renbin Yan
Physics and Astronomy Faculty Publications
We conduct a systematic study of galactic outflows in star-forming galaxies at z ~ 0–2 based on the absorption lines of optical spectra taken from SDSS DR7, DEEP2 DR4, and Keck (Erb et al.). We carefully make stacked spectra of homogeneous galaxy samples with similar stellar mass distributions at z ~ 0–2 and perform the multicomponent fitting of model absorption lines and stellar continua to the stacked spectra. We obtain the maximum (vmax) and central (vout) outflow velocities and estimate the mass loading factors (η), a ratio of the mass outflow rate …
Sdss-Iv Manga: Constraints On The Conditions For Star Formation In Galaxy Discs, David V. Stark, Kevin A. Bundy, Matthew E. Orr, Philip F. Hopkins, Kyle Westfall, Matthew Bershady, Cheng Li, Dmitry Bizyaev, Karen L. Masters, Anne-Marie Weijmans, Ivan Lacerna, Daniel Thomas, Niv Drory, Renbin Yan, Kai Zhang
Sdss-Iv Manga: Constraints On The Conditions For Star Formation In Galaxy Discs, David V. Stark, Kevin A. Bundy, Matthew E. Orr, Philip F. Hopkins, Kyle Westfall, Matthew Bershady, Cheng Li, Dmitry Bizyaev, Karen L. Masters, Anne-Marie Weijmans, Ivan Lacerna, Daniel Thomas, Niv Drory, Renbin Yan, Kai Zhang
Physics and Astronomy Faculty Publications
Regions of disc galaxies with widespread star formation tend to be both gravitationally unstable and self-shielded against ionizing radiation, whereas extended outer discs with little or no star formation tend to be stable and unshielded on average. We explore what drives the transition between these two regimes, specifically whether discs first meet the conditions for self-shielding (parametrized by dust optical depth, τ) or gravitational instability (parametrized by a modified version of Toomre's instability parameters, Qthermal, which quantifies the stability of a gas disc that is thermally supported at T = 104 K). We first introduce a new …
The Carbon And Nitrogen Abundance Ratio In The Broad Line Region Of Tidal Disruption Events, Chenwei Yang, Tinggui Wang, Gary J. Ferland, Liming Dou, Hongyan Zhou, Ning Jiang, Zhenfeng Sheng
The Carbon And Nitrogen Abundance Ratio In The Broad Line Region Of Tidal Disruption Events, Chenwei Yang, Tinggui Wang, Gary J. Ferland, Liming Dou, Hongyan Zhou, Ning Jiang, Zhenfeng Sheng
Physics and Astronomy Faculty Publications
The rest-frame UV spectra of three recent tidal disruption events (TDEs), ASASSN-14li, PTF15af, and iPTF16fnl, display strong nitrogen emission lines but weak or undetectable carbon lines. In these three objects, the upper limits of the C III] λ1908/N III] λ1750 ratio are about two orders of magnitude lower than those of quasars, suggesting a high abundance ratio of [N/C]. With detailed photoionization simulations, we demonstrate that C2+ and N2+ are formed in the same zone, so the CIII]/N III] ratio depends only moderately on the physical conditions in the gas and weakly on the shape of …
Quantum Quench And Scaling Of Entanglement Entropy, Pawel Caputa, Sumit R. Das, Masahiro Nozaki, Akio Tomiya
Quantum Quench And Scaling Of Entanglement Entropy, Pawel Caputa, Sumit R. Das, Masahiro Nozaki, Akio Tomiya
Physics and Astronomy Faculty Publications
Global quantum quench with a finite quench rate which crosses critical points is known to lead to universal scaling of correlation functions as functions of the quench rate. In this work, we explore scaling properties of the entanglement entropy of a subsystem in a harmonic chain during a mass quench which asymptotes to finite constant values at early and late times and for which the dynamics is exactly solvable. When the initial state is the ground state, we find that for large enough subsystem sizes the entanglement entropy becomes independent of size. This is consistent with Kibble–Zurek scaling for slow …
Photoelectrochemical Cell Including Ga(SbX)N1-X Semiconductor Electrode, Madhu Menon, Michael Sheetz, Mahendra Kumar Sunkara, Chandrashekhar Pendyala, Swathi Sunkara, Jacek B. Jasinksi
Photoelectrochemical Cell Including Ga(SbX)N1-X Semiconductor Electrode, Madhu Menon, Michael Sheetz, Mahendra Kumar Sunkara, Chandrashekhar Pendyala, Swathi Sunkara, Jacek B. Jasinksi
Physics and Astronomy Faculty Patents
The composition of matter comprising Ga(Sbx)N1−x where x=0.01 to 0.06 is characterized by a band gap between 2.4 and 1.7 eV. A semiconductor device includes a semiconductor layer of that composition. A photoelectric cell includes that semiconductor device.
Holographic Entanglement Entropy Of A 1 + 1 Dimensional P-Wave Superconductor, Sumit R. Das, Mitsutoshi Fujita, Bom Soo Kim
Holographic Entanglement Entropy Of A 1 + 1 Dimensional P-Wave Superconductor, Sumit R. Das, Mitsutoshi Fujita, Bom Soo Kim
Physics and Astronomy Faculty Publications
We examine the behavior of entanglement entropy S A EE of a subsystem A in a fully backreacted holographic model of a 1 + 1 dimensional p wave superconductor across the phase transition. For a given temperature, the system goes to a superconducting phase beyond a critical value of the charge density. The entanglement entropy, considered as a function of the charge density at a given temperature, has a cusp at the critical point. In addition, we find that there are three different behaviors in the condensed phase, depending on the subsystem size. For a subsystem size l smaller than …
Three Dimensional View Of The Syk/Ads Duality, Sumit R. Das, Antal Jevicki, Kenta Suzuki
Three Dimensional View Of The Syk/Ads Duality, Sumit R. Das, Antal Jevicki, Kenta Suzuki
Physics and Astronomy Faculty Publications
We show that the spectrum of the SYK model can be interpreted as that of a 3D scalar coupled to gravity. The scalar has a mass which is at the Breitenholer-Freedman bound of AdS2, and subject to a delta function potential at the center of the interval along the third direction. This, through Kaluza-Klein procedure on AdS2 × (S1)/Z2, generates the spectrum reproducing the bi-local propagator at strong coupling. Furthermore, the leading 1/J correction calculated in this picture reproduces the known correction to the poles of the SYK propagator, providing …
Space Telescope And Optical Reverberation Mapping Project. Vii. Understanding The Ultraviolet Anomaly In Ngc 5548 With X-Ray Spectroscopy, S. Mathur, A. Gupta, K. Page, R. W. Pogge, Y. Krongold, M. R. Goad, S. M. Adams, M. D. Anderson, P. Arévalo, A. J. Barth, C. Bazhaw, T. G. Beatty, M. C. Bentz, A. Bigley, S. Bisogni, G. A. Borman, T. A. Boroson, M. C. Bottorff, W. N. Brandt, A. A. Breeveld, J. E. Brown, J. S. Brown, E. M. Cackett, G. Canalizo, M. T. Carini, K. I. Clubb, J. M. Comerford, C. T. Coker, E. M. Corsini, D. M. Crenshaw, Gary J. Ferland
Space Telescope And Optical Reverberation Mapping Project. Vii. Understanding The Ultraviolet Anomaly In Ngc 5548 With X-Ray Spectroscopy, S. Mathur, A. Gupta, K. Page, R. W. Pogge, Y. Krongold, M. R. Goad, S. M. Adams, M. D. Anderson, P. Arévalo, A. J. Barth, C. Bazhaw, T. G. Beatty, M. C. Bentz, A. Bigley, S. Bisogni, G. A. Borman, T. A. Boroson, M. C. Bottorff, W. N. Brandt, A. A. Breeveld, J. E. Brown, J. S. Brown, E. M. Cackett, G. Canalizo, M. T. Carini, K. I. Clubb, J. M. Comerford, C. T. Coker, E. M. Corsini, D. M. Crenshaw, Gary J. Ferland
Physics and Astronomy Faculty Publications
During the Space Telescope and Optical Reverberation Mapping Project observations of NGC 5548, the continuum and emission-line variability became decorrelated during the second half of the six-month-long observing campaign. Here we present Swift and Chandra X-ray spectra of NGC 5548 obtained as part of the campaign. The Swift spectra show that excess flux (relative to a power-law continuum) in the soft X-ray band appears before the start of the anomalous emission-line behavior, peaks during the period of the anomaly, and then declines. This is a model-independent result suggesting that the soft excess is related to the anomaly. We divide the …
Inside-Out Growth Or Inside-Out Quenching? Clues From Colour Gradients Of Local Galaxies, Jianhui Lian, Renbin Yan, Michael Blanton, Xu Kong
Inside-Out Growth Or Inside-Out Quenching? Clues From Colour Gradients Of Local Galaxies, Jianhui Lian, Renbin Yan, Michael Blanton, Xu Kong
Physics and Astronomy Faculty Publications
We constrain the spatial gradient of star formation history (SFH) within galaxies using the colour gradients in NUV − u (where NUV stands for near-ultraviolet) and u − i for a local spatially resolved galaxy sample. By splitting each galaxy into an inner and an outer part, we find that most galaxies show negative gradients in these two colours. We first rule out dust extinction gradient and metallicity gradient as the dominant source for the colour gradient. Then using stellar population models, we explore variations in SFH to explain the colour gradients. As shown by our earlier work, a two-phase …
Entanglement Entropy With Background Gauge Fields, Bom Soo Kim
Entanglement Entropy With Background Gauge Fields, Bom Soo Kim
Physics and Astronomy Faculty Publications
We study the entanglement entropy, the Rényi entropy, and the mutual (Rényi) information of Dirac fermions on a 2 dimensional torus in the presence of constant gauge fields. We derive their general formulas using the equivalence between twisted boundary conditions and the background gauge fields. Novel and interesting physical consequences have been presented in arXiv:1705.01859. Here we provide detailed computations of the entropies and mutual information in a low temperature limit, a large radius limit, and a high temperature limit. The high temperature limit reveals rather different physical properties compared to those of the low temperature one: there exist …
Energy Dependence Of J/Ψ Production In Au + Au Collisions At √SNn = 39, 62.4 And 200 Gev, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, N. N. Ajitanand, I. Alekseev, D. M. Anderson, R. Aoyama, A. Aparin, D. Arkhipkin, E. C. Aschenauer, M. U. Ashraf, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, A. Behera, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. Bouchet, J. D. Brandenburg, A. V. Brandin, D. Brown, Renee H. Fatemi, Suvarna Ramachandran
Energy Dependence Of J/Ψ Production In Au + Au Collisions At √SNn = 39, 62.4 And 200 Gev, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, N. N. Ajitanand, I. Alekseev, D. M. Anderson, R. Aoyama, A. Aparin, D. Arkhipkin, E. C. Aschenauer, M. U. Ashraf, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, A. Behera, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. Bouchet, J. D. Brandenburg, A. V. Brandin, D. Brown, Renee H. Fatemi, Suvarna Ramachandran
Physics and Astronomy Faculty Publications
The inclusive J/ψ transverse momentum spectra and nuclear modification factors are reported at midrapidity (|y| < 1.0) in Au + Au collisions at √sNN = 39, 62.4 and 200 GeV taken by the STAR experiment. A suppression of J/ψ production, with respect to the production in p + p scaled by the number of binary nucleon–nucleon collisions, is observed in central Au + Au collisions at these three energies. No significant energy dependence of nuclear modification factors is found within uncertainties. The measured nuclear modification factors can be described by model calculations that take into account both suppression of direct J/ψ production due to …
The Sdss-Iv Manga Sample: Design, Optimization, And Usage Considerations, David A. Wake, Kevin Bundy, Aleksandar M. Diamond-Stanic, Renbin Yan, Michael R. Blanton, Matthew A. Bershady, José R. Sánchez-Gallego, Niv Drory, Amy Jones, Guinevere Kauffmann, David R. Law, Cheng Li, Nicholas Macdonald, Karen Masters, Daniel Thomas, Jeremy Tinker, Anne-Marie Weijmans, Joel R. Brownstein
The Sdss-Iv Manga Sample: Design, Optimization, And Usage Considerations, David A. Wake, Kevin Bundy, Aleksandar M. Diamond-Stanic, Renbin Yan, Michael R. Blanton, Matthew A. Bershady, José R. Sánchez-Gallego, Niv Drory, Amy Jones, Guinevere Kauffmann, David R. Law, Cheng Li, Nicholas Macdonald, Karen Masters, Daniel Thomas, Jeremy Tinker, Anne-Marie Weijmans, Joel R. Brownstein
Physics and Astronomy Faculty Publications
We describe the sample design for the SDSS-IV MaNGA survey and present the final properties of the main samples along with important considerations for using these samples for science. Our target selection criteria were developed while simultaneously optimizing the size distribution of the MaNGA integral field units (IFUs), the IFU allocation strategy, and the target density to produce a survey defined in terms of maximizing signal-to-noise ratio, spatial resolution, and sample size. Our selection strategy makes use of redshift limits that only depend on i-band absolute magnitude (Mi ), or, for a small subset of our sample, …
Accelerator Based Fusion Reactor, Keh-Fei Liu, Alexander Wu Chao
Accelerator Based Fusion Reactor, Keh-Fei Liu, Alexander Wu Chao
Physics and Astronomy Faculty Publications
A feasibility study of fusion reactors based on accelerators is carried out. We consider a novel scheme where a beam from the accelerator hits the target plasma on the resonance of the fusion reaction and establish characteristic criteria for a workable reactor. We consider the reactions d+t→n+α, d+3He→p+α and p+11B→3α in this study. The critical temperature of the plasma is determined from overcoming the stopping power of the beam with the fusion energy gain. The needed plasma lifetime is determined …
Milky Way Tomography With K And M Dwarf Stars: The Vertical Structure Of The Galactic Disk, Deborah Ferguson, Susan Gardner, Brian Yanny
Milky Way Tomography With K And M Dwarf Stars: The Vertical Structure Of The Galactic Disk, Deborah Ferguson, Susan Gardner, Brian Yanny
Physics and Astronomy Faculty Publications
We use the number density distributions of K and M dwarf stars with vertical height from the Galactic disk, determined using observations from the Sloan Digital Sky Survey, to probe the structure of the Milky Way disk across the survey's footprint. Using photometric parallax as a distance estimator we analyze a sample of several million disk stars in matching footprints above and below the Galactic plane, and we determine the location and extent of vertical asymmetries in the number counts in a variety of thin- and thick-disk subsamples in regions of some 200 square degrees within 2 kpc in vertical …
The Validity Of 21 Cm Spin Temperature As A Kinetic Temperature Indicator In Atomic And Molecular Gas, Gargi Shaw, Gary J. Ferland, I. Hubeny
The Validity Of 21 Cm Spin Temperature As A Kinetic Temperature Indicator In Atomic And Molecular Gas, Gargi Shaw, Gary J. Ferland, I. Hubeny
Physics and Astronomy Faculty Publications
The gas kinetic temperature (TK) of various interstellar environments is often inferred from observations that can deduce level populations of atoms, ions, or molecules using spectral line observations; H I 21 cm is perhaps the most widely used, and has a long history. Usually the H I 21 cm line is assumed to be in thermal equilibrium and the populations are given by the Boltzmann distribution. A variety of processes, many involving Lyα, can affect the 21 cm line. Here we show how this is treated in the spectral simulation code Cloudy, and present numerical …
Direct Virtual Photon Production In Au+Au Collisions At √SNn = 200 Gev, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, N. N. Ajitanand, I. Alekseev, D. M. Anderson, R. Aoyama, A. Aparin, D. Arkhipkin, E. C. Aschenauer, M. U. Ashraf, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, A. Behera, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. Bouchet, J. D. Brandenburg, A. V. Brandin, D. Brown, Renee H. Fatemi, Suvarna Ramachandran
Direct Virtual Photon Production In Au+Au Collisions At √SNn = 200 Gev, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, N. N. Ajitanand, I. Alekseev, D. M. Anderson, R. Aoyama, A. Aparin, D. Arkhipkin, E. C. Aschenauer, M. U. Ashraf, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, A. Behera, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. Bouchet, J. D. Brandenburg, A. V. Brandin, D. Brown, Renee H. Fatemi, Suvarna Ramachandran
Physics and Astronomy Faculty Publications
We report the direct virtual photon invariant yields in the transverse momentum ranges 1 < pT < 3 GeV/c and 5 < pT < 10 GeV/c at mid-rapidity derived from the dielectron invariant mass continuum region 0.10 < Mee < 0.28 GeV/c2 for 0–80% minimum-bias Au+Au collisions at √sNN = 200 GeV. A clear excess in the invariant yield compared to the nuclear overlap function TAA scaled p + p reference is observed in the pT range 1 < pT < 3 GeV/c. For pT > 6 GeV/c the production follows TAA scaling. Model calculations with contributions from thermal radiation …
Ionic Thermoelectric Paper, Fei Jiao, Ali Naderi, Dan Zhao, Joshua Schlueter, Maryam Shahi, Jonas Sundström, Hjalmar Granberg, Jesper Edberg, Ujwala Ail, Joseph W. Brill, Tom Lindström, Magnus Berggren, Xavier Crispin
Ionic Thermoelectric Paper, Fei Jiao, Ali Naderi, Dan Zhao, Joshua Schlueter, Maryam Shahi, Jonas Sundström, Hjalmar Granberg, Jesper Edberg, Ujwala Ail, Joseph W. Brill, Tom Lindström, Magnus Berggren, Xavier Crispin
Physics and Astronomy Faculty Publications
Ionic thermoelectric materials, for example, polyelectrolytes such as polystyrene sulfonate sodium (PSSNa), constitute a new class of materials which are attracting interest because of their large Seebeck coefficient and the possibility that they could be used in ionic thermoelectric SCs (ITESCs) and field effect transistors. However, pure polyelectrolyte membranes are not robust or flexible. In this paper, the preparation of ionic thermoelectric paper using a simple, scalable and cost-effective method is described. After a composite was fabricated with nanofibrillated cellulose (NFC), the resulting NFC–PSSNa paper is flexible and mechanically robust, which is desirable if it is to be used in …
Sloan Digital Sky Survey Iv: Mapping The Milky Way, Nearby Galaxies, And The Distant Universe, Michael R. Blanton, Matthew A. Bershady, Bela Abolfathi, Franco D. Albareti, Carlos Allende Prieto, Andres Almeida, Javier Alonso-García, Friedrich Anders, Scott F. Anderson, Brett Andrews, Erik Aquino-Ortíz, Alfonso Aragón-Salamanca, Maria Argudo-Fernández, Eric Armengaud, Eric Aubourg, Vladimir Avila-Reese, Carles Badenes, Stephen Bailey, Kathleen A. Barger, Jorge Barrera-Ballesteros, Curtis Bartosz, Dominic Bates, Falk Baumgarten, Julian Bautista, Rachael Beaton, Francesco Belfiore, Chad F. Bender, Andreas A. Berlind, Mariangela Bernardi, Florian Beutler, Renbin Yan, Daniel Lazarz, Kai Zhang
Sloan Digital Sky Survey Iv: Mapping The Milky Way, Nearby Galaxies, And The Distant Universe, Michael R. Blanton, Matthew A. Bershady, Bela Abolfathi, Franco D. Albareti, Carlos Allende Prieto, Andres Almeida, Javier Alonso-García, Friedrich Anders, Scott F. Anderson, Brett Andrews, Erik Aquino-Ortíz, Alfonso Aragón-Salamanca, Maria Argudo-Fernández, Eric Armengaud, Eric Aubourg, Vladimir Avila-Reese, Carles Badenes, Stephen Bailey, Kathleen A. Barger, Jorge Barrera-Ballesteros, Curtis Bartosz, Dominic Bates, Falk Baumgarten, Julian Bautista, Rachael Beaton, Francesco Belfiore, Chad F. Bender, Andreas A. Berlind, Mariangela Bernardi, Florian Beutler, Renbin Yan, Daniel Lazarz, Kai Zhang
Physics and Astronomy Faculty Publications
We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median z ~ 0.03). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between z ~ 0.6 and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, …
Atomic Data Revisions For Transitions Relevant To Observations Of Interstellar, Circumgalactic, And Intergalactic Matter, Frances H. Cashman, Varsha P. Kulkarni, Romas Kisielius, Gary J. Ferland, Pavel Bogdanovich
Atomic Data Revisions For Transitions Relevant To Observations Of Interstellar, Circumgalactic, And Intergalactic Matter, Frances H. Cashman, Varsha P. Kulkarni, Romas Kisielius, Gary J. Ferland, Pavel Bogdanovich
Physics and Astronomy Faculty Publications
Measurements of element abundances in galaxies from astrophysical spectroscopy depend sensitively on the atomic data used. With the goal of making the latest atomic data accessible to the community, we present a compilation of selected atomic data for resonant absorption lines at wavelengths longward of 911.753 Å (the H I Lyman limit), for key heavy elements (heavier than atomic number 5) of astrophysical interest. In particular, we focus on the transitions of those ions that have been observed in the Milky Way interstellar medium (ISM), the circumgalactic medium (CGM) of the Milky Way and/or other galaxies, and the intergalactic medium …
Emission Line Ratios Of Fe Iii As Astrophysical Plasma Diagnostics, Sibasish Laha, Niall B. Tyndall, Francis P. Keenan, Connor P. Ballance, Catherine A. Ramsbottom, Gary J. Ferland, Alan Hibbert
Emission Line Ratios Of Fe Iii As Astrophysical Plasma Diagnostics, Sibasish Laha, Niall B. Tyndall, Francis P. Keenan, Connor P. Ballance, Catherine A. Ramsbottom, Gary J. Ferland, Alan Hibbert
Physics and Astronomy Faculty Publications
Recent, state-of-the-art calculations of A-values and electron impact excitation rates for Fe III are used in conjunction with the Cloudy modeling code to derive emission-line intensity ratios for optical transitions among the fine-structure levels of the 3d6 configuration. A comparison of these with high-resolution, high signal-to-noise spectra of gaseous nebulae reveals that previous discrepancies found between theory and observation are not fully resolved by the latest atomic data. Blending is ruled out as a likely cause of the discrepancies, because temperature- and density-independent ratios (arising from lines with common upper levels) match well with those predicted by theory. For …
Swift Monitoring Of Ngc 4151: Evidence For A Second X-Ray/Uv Reprocessing, R. Edelson, J. Gelbord, E. Cackett, S. Connolly, C. Done, M. Fausnaugh, E. Gardner, N. Gehrels, M. Goad, K. Horne, I. Mchardy, B. M. Peterson, S. Vaughan, M. Vestergaard, A. Breeveld, A. J. Barth, M. Bentz, M. Bottorff, W. N. Brandt, S. M. Crawford, E. Dalla Bontà, D. Emmanoulopoulos, P. Evans, R. Figuera Jaimes, A. V. Filippenko, Gary J. Ferland, D. Grupe, M. Joner, J. Kennea, K. T. Korista
Swift Monitoring Of Ngc 4151: Evidence For A Second X-Ray/Uv Reprocessing, R. Edelson, J. Gelbord, E. Cackett, S. Connolly, C. Done, M. Fausnaugh, E. Gardner, N. Gehrels, M. Goad, K. Horne, I. Mchardy, B. M. Peterson, S. Vaughan, M. Vestergaard, A. Breeveld, A. J. Barth, M. Bentz, M. Bottorff, W. N. Brandt, S. M. Crawford, E. Dalla Bontà, D. Emmanoulopoulos, P. Evans, R. Figuera Jaimes, A. V. Filippenko, Gary J. Ferland, D. Grupe, M. Joner, J. Kennea, K. T. Korista
Physics and Astronomy Faculty Publications
Swift monitoring of NGC 4151 with an ~6 hr sampling over a total of 69 days in early 2016 is used to construct light curves covering five bands in the X-rays (0.3–50 keV) and six in the ultraviolet (UV)/optical (1900–5500 Å). The three hardest X-ray bands (> 2.5 keV) are all strongly correlated with no measurable interband lag, while the two softer bands show lower variability and weaker correlations. The UV/optical bands are significantly correlated with the X-rays, lagging ~3–4 days behind the hard X-rays. The variability within the UV/optical bands is also strongly correlated, with the UV appearing to …
A Local Leaky-Box Model For The Local Stellar Surface Density-Gas Surface Density-Gas Phase Metallicity Relation, Guangtun Ben Zhu, Jorge K. Barrera-Ballesteros, Timothy M. Heckman, Nadia L. Zakamska, Sebastian F. Sánchez, Renbin Yan, Jonathan Brinkman
A Local Leaky-Box Model For The Local Stellar Surface Density-Gas Surface Density-Gas Phase Metallicity Relation, Guangtun Ben Zhu, Jorge K. Barrera-Ballesteros, Timothy M. Heckman, Nadia L. Zakamska, Sebastian F. Sánchez, Renbin Yan, Jonathan Brinkman
Physics and Astronomy Faculty Publications
We revisit the relation between the stellar surface density, the gas surface density and the gas-phase metallicity of typical disc galaxies in the local Universe with the SDSS-IV/MaNGA survey, using the star formation rate surface density as an indicator for the gas surface density. We show that these three local parameters form a tight relationship, confirming previous works (e.g. by the PINGS and CALIFA surveys), but with a larger sample. We present a new local leaky-box model, assuming star-formation history and chemical evolution is localized except for outflowing materials. We derive closed-form solutions for the evolution of stellar surface density, …
Which Stars Are Ionizing The Orion Nebula?, C. R. O'Dell, W. Kollatschny, Gary J. Ferland
Which Stars Are Ionizing The Orion Nebula?, C. R. O'Dell, W. Kollatschny, Gary J. Ferland
Physics and Astronomy Faculty Publications
The common assumption that θ1 Ori C is the dominant ionizing source for the Orion Nebula is critically examined. This assumption underlies much of the existing analysis of the nebula. In this paper we establish through comparison of the relative strengths of emission lines with expectations from Cloudy models and through the direction of the bright edges of proplyds that θ2 Ori A, which lies beyond the Bright Bar, also plays an important role. θ1 Ori C does dominate ionization in the inner part of the Orion Nebula, but outside of the Bright Bar as far as …
Space Telescope And Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign And Emission-Line Analysis For Ngc 5548, L. Pei, M. M. Fausnaugh, A. J. Barth, B. M. Peterson, M. C. Bentz, G. De Rosa, K. D. Denney, M. R. Goad, C. S. Kochanek, K. T. Korista, G. A. Kriss, R. W. Pogge, V. N. Bennert, M. Brotherton, K. I. Clubb, E. Dalla Bontà, A. V. Filippenko, J. E. Greene, C. J. Grier, M. Vestergaard, W. Zheng, Scott M. Adams, Thomas G. Beatty, A. Bigley, Jacob E. Brown, Jonathan S. Brown, G. Canalizo, J. M. Comerford, Carl T. Coker, E. M. Corsini, Gary J. Ferland, S. A. Klimanov
Space Telescope And Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign And Emission-Line Analysis For Ngc 5548, L. Pei, M. M. Fausnaugh, A. J. Barth, B. M. Peterson, M. C. Bentz, G. De Rosa, K. D. Denney, M. R. Goad, C. S. Kochanek, K. T. Korista, G. A. Kriss, R. W. Pogge, V. N. Bennert, M. Brotherton, K. I. Clubb, E. Dalla Bontà, A. V. Filippenko, J. E. Greene, C. J. Grier, M. Vestergaard, W. Zheng, Scott M. Adams, Thomas G. Beatty, A. Bigley, Jacob E. Brown, Jonathan S. Brown, G. Canalizo, J. M. Comerford, Carl T. Coker, E. M. Corsini, Gary J. Ferland, S. A. Klimanov
Physics and Astronomy Faculty Publications
We present the results of an optical spectroscopic monitoring program targeting NGC 5548 as part of a larger multiwavelength reverberation mapping campaign. The campaign spanned 6 months and achieved an almost daily cadence with observations from five ground-based telescopes. The Hβ and He ii λ4686 broad emission-line light curves lag that of the 5100 Å optical continuum by 4.17+0.36 -0.36 days and 0.79+0.35-0.34 days respectively. The Hβ lag relative to the 1158 Å ultraviolet continuum light curve measured by the Hubble Space Telescope is ~50% longer than that measured against the optical continuum, and …