May 13-16th 2019 Madren Conference Center

Clemson University

Laboratory Astrophysics in the Era of Multi-messenger Astronomy

MondayM

ay13thTuesdayM

ay14thWednesdayM

ay15thThursdayM

ay16th

GraduateStudentSymposium

Session1Session5

Session89:00-9:30am

BruceRemington

JimLaw

lerSlavaKookoouline

9:30-10:00amAhm

adNemer

JamesClark

AnthonyDeStefano10:00-10:30am

Bromley/Zhang

CoffeeBreakDieterHartm

annCoffeeBreak

Session210:30-11:00am

Zhou/Flowers

NicoleVasshSCBGExcursion

TomGorczyca

11:00-11:30amLabAstroCareersQ

&A

BradMeyer

PanelDiscussion-Fogle11:30-12:00pm

BrendanMcLaughlin

Wrap-up-Stancil

12:00-12:30pmLunch/CVw

orkshopLunch

12:30-1:00pmLunch

1:00-1:30pmPictureSession3

Session61:30-2:00pm

Gall/Taghadomi

JoanMarler

MarkZam

mit

2:00-2:30pmNam

in/Webster

AvirupRoyMitchPindzola

2:30-3:00pmCoffeeBreak

CoffeeBreakCoffeeBreak

Session4Session7

3:00-3:30pmLabAstroScienceQ

&A

FranGuzman

GillianNave3:30-4:00pm

ManuelBautista

JeffShinpaugh4:00-4:30pm

PosterSessionPosterSession

6:00pm

6:30-7:00pm

SELAC19Welcom

eReceptionConferenceDinner

7:00-7:30pm

SoutheastLaboratoryAstrophysicsCommunityWorkshopGraduate Student Symposium

MONDAY 13 May Session 1 10:00 am Steve Bromley – Clemson University

HighResolutionUV-VISSpectroscopyofAuI,AuII,AuIIIusingPlasmaSources

10:15 am Ziwei Zhang – University of Georgia MolecularProbesinHighlyIrradiatedGas:Non-thermalrotationalandvibrationalemissioninenergeticenvironments

10:30 am Boyi Zhou – University of Georgia TheratecoefficientsofreactivescatteringofHDbyHydrogen

10:45 am Alicia Flowers – University of Georgia

ModelingOpacityforSpectraofHeavyElements

11:00 am Panel Topic: Careers with Laboratory Astrophysics PhD Session 2 1:30 pm Amy Gall – Clemson University

EBITObservationofArDielectronicRecombinationLinesneartheUnknownFaintX-RayFeatureFoundintheStackedSpectrumofGalaxyClusters

1:45 pm Zahra Taghadomi– University of Georgia ModelingOpacityforSpectraofHeavyElements

2:00 pm Mona Namin – University of Georgia MysteriousIce

2:15 pm Ian Webster– University of Georgia

LargePolycyclicAromaticHydrocarbonFormationviaLaser-InducedOligamerization

3:00 pm Panel Topic: Unanswered Questions in Laboratory Astrophysics

SoutheastLaboratoryAstrophysicsCommunityWorkshop

ClemsonUniversity,Clemson,SC

13-16thMay,2019TUESDAY 14 May Session 1 Chair: E. Takacs, Clemson 9:00 am Dr. Bruce Remington – LLNL

ExploringtheuniversethroughDiscoveryScienceonNIF*

9:30 am Mr. Ahmad Nemer - Auburn University Discoveryofenhancedrecombinationinastrophysicalenvironmentsandtheimplicationsforplasmadiagnostics

Session 2 Chair: C. E. Sosolik, Clemson 10:30 am Dr. Nicole Vassh - University of Notre Dame

FissionandLanthanideProductioninr-processNucleosynthesis11:00 am Dr. Brad Meyer - Clemson University

Heavy-ElementNucleosynthesis

11:30 am Dr. Brendan McLaughin - Queen’s University Belfast TheLIGOproject:AuandPtsequencesforneutronstarmergeropacities

Session 3 Chair: M. Fogle, Auburn 1:30 pm Dr. Joan Marler - Clemson University

Spectroscopyofmultichargedheavyatomsforelementformationidentification

2:00 pm Mr. Avirup Roy - University of Wisconsin HighResolutionMeasurementsFollowingChargeExchangewithH:Dataforanewobservationalwindowondiffuseastrophysicalsources

Session 4 Chair: M. Pindzola, Auburn 3:00 pm Dr. Fran Guzman - University of Kentucky

AtomicCollisionsthatshapethelightoftheuniverse:latestdevelopmentsinCloudy

3:30 pm Dr. Manuel Bautista - Western Michigan University

UncertaintiesinR-matrixScatteringCalculations.ConvergedExpansions?and,Convergencetowhat?

WEDNESDAY 15 May Session 5 Chair: P. C. Stancil, University of Georgia 9:00 am Dr. Jim Lawler - -University of Wisconsin

LabAstroforStellarSpectroscopyintheMulti-messengerEra 9:30 am Dr. James Clark – Georgia Tech TheWindowIsOpen!TheCosmicLaboratoryOfLIGO-Virgo

Gravitational-waveObservations 10:00 am Dr. Dieter Hartmann – Clemson University

Multi-MessengerAstrophysicsandTimeDomainAstronomy Session 6 Chair: S. Loch, Auburn 1:30 pm Dr. Mark Zammit – Los Alamos National Labs

Moleculardataforastrophysicalhydrogenplasmamodeling

2:00 pm Dr. Mitch Pindzola - Auburn University ChargeExchangeinBareIonInteractionswithHydrogenandHeliumAtoms

Session 7 Chair: S. J. Bromley, Clemson 3:00 pm Dr. Gillian Nave – NIST

Comprehensiveatomicdataforsingly-ionizediron-groupelements 3:30 pm Dr. Jeff Shinpaugh –East Carolina University

Ioninducedelectronemissionfromicesandhydratedmetalsurfaces

THURSDAY 16 May Session 8: Chair: J. P. Marler, Clemson 9:00 am Dr. Viatcheslav Kokoouline - University of Central Florida

“Universal”theoreticalapproachfordeterminationofcrosssectionsfordissociativerecombination,rotational,vibrational,electronicexcitationofmolecularions

9:30 am Mr. Anthony De Stefano - University of Alabama – Huntsville HeavyAtomsandtheHeliospheredrivenbyCharge-Exchange

10:00 am Dr. Tom Gorczyca - Western Michigan University X-rayAbsorptionModelsforInterstellarO,Si,andFe:Atomicvs.Molecular/Solid-StateAbsorbers

11:00 am Panel discussion on Physics Frontier Centers Mike Fogle 11:30 am Conference Wrap-Up Phillip Stancil

SoutheastLaboratoryAstrophysicsCommunityWorkshop

Posters

P01 Steve Bromley – Clemson University C. A. Johnson, C. E. Sosolik, D. A. Ennis, P. C. Stancil, S. D. Loch, J. P. Marler HighResolutionUV-VISSpectroscopyofAuI,AuII,AuIII

P02 Benhui Yang– University of Georgia

P. C.Stancil, P. Zhang, J. M. Bowman, N. Balakrishnan,R. C. Forrey Full-dimensionalQuantumDynamicsofCO,CN,SiO,andCSinCollisionswithH2

P03 Kyle Stewart – Auburn University

Stuart Loch, Hans Werner Van Wyk, Adam Foster Estimatinguncertaintiesindielectronicrecombinationratecoefficientsforuseinastrophysicalmodeling

P04 Ian Webster - University of Georgia

Jacob L. Beckham, Natalie M. Johnson, Michael A. Duncan SynthesisandCharacterizationofLargePAHSamplesviaLaserPhotochemicalPolymerization

P05 Norberto Davila – Clemson University

B. Meyer ExplosiveHeliumShellNucleosynthesis

P06 Anthony M. DeStefano - University of Alabama in Huntsville

HeavyAtomsandtheHeliospheredrivenbyCharge-Exchange P07 Hala – NIST

G. Nave; J. E. Lawler AccurateMeasurementofAtomicDataUsingHighResolutionFourierTransformSpectrometers

P08 Alicia Flowers – University of Georgia

Y. Wan, Z. Taghadomi, P. C. Stancil, B. McLaughlin, S. Loch, S. J. Bromley, J. P. Marler, C. E. Sosolik RelativisticAtomicStructureoftheAuIIIsoelectronicSequence:opacitydataforkilonovaejecta

P09 Yier Wan - University of Georgia

Z. Taghadomi, A. Flowers, P. C. Stancil, B.M. McLaughlin, S. Loch, S.J. Bromley, J. P. Marler, and C. E. Sosolik RelativisticAtomicStructureoftheAuIIIIsoelectronicSequence:opacitydataforkilonovaejecta

P10 Zahra Taghadomi – University of Georgia

Y. Wan, A. Flowers, P. Stancil, B. M. McLaughlin, S. Loch, S. J. Bromley, J. P. Marler, C. E. Sosolik RelativisticAtomicStructureoftheAuIVIsoelectronicSequence:opacitydataforkilonovaejecta

P11 Timothy Burke – Clemson University S. J. Bromley, E. Takacs, J. P. Marler ProductionandexplorationofRydbergHighlyChargedIons

Exploring the Universe through Discovery Science on NIF

Bruce A. Remington

Lawrence Livermore National Laboratory, Livermore, CA USA An overview of recent research done on the 2 MJ, 192 beam NIF laser facility at LLNL through the NIF Discovery Science program will be presented. A selection of examples will be drawn from experimental studies of equations of state of H, C, CH, and Fe at high pressures (Pmax > 100 Mbar) and densities relevant to planetary interiors [1 - 5]; heat conduction stabilized Rayleigh-Taylor instability growth relevant to supernova remnants [6, 7]; high velocity, low density interpenetrating plasma flows that can generate collisionless astrophysical shocks relevant to galactic collisions, supernova remnants, Herbig- Haro jets, and particle acceleration leading to cosmic ray generation. [8, 9] We then will focus on and conclude with a summary of recent experiments done on NIF, Omega, and other HED laser facilities to study unique regimes of nuclear astrophysics relevant to star formation (stellar birth), stellar evolution, supernova explosions (stellar death), and stellar and big bang nucleosynthesis. [10-14]

[1] Raymond F. Smith et al., “Equation of state of iron under core conditions of large rocky exoplanets,” Nature Astronomy 2, 452 (June 2018). [2] R. F. Smith et al., “Ramp compression of diamond to five terapascals,” Nature 511, 330 (2014). [3] Tilo Doppner et al, “Absolute Equation-of-State measurement from 25 to 60 Mbar using a spherically converging shock wave,” Physical Review Letters 121, 025001 (2018). [4] Andrea Kritcher et al., “Equation of state measurements in the atomic pressure regime, exceeding 300 million atmospheres,” Nature Physics, to be submitted (Jan. 2019). [5] Bruce A. Remington et al., “From microjoules to megajoules and kilobars to gigabars: probing matter at extreme states of deformation,” Physics of Plasmas 22, 090501 (2015). [6] Carolyn C. Kuranz et al, “How high energy fluxes may affect Rayleigh-Taylor instability growth in young supernova remnants,” Nature Communications 9, 1564 (2018). [7] B.A. Remington et al., “Rayleigh-Taylor instabilities in high-energy-density settings on NIF,” Proceedings of the National Academy of Sciences of the United States of America (June 26, 2018), <www.pnas.org/cgi/cgi/doi/10.1073/pnas.1717236115>. [8] J. S. Ross et al., “Transition from collisional to collisionless regimes in interpenetrating plasma flows on the NIF,” Physical Review Letters 118, 185003 (2017). [9] C.M. Huntington et al., “Observation of magnetic field generation via the Weibel instability in interpenetrating plasma flows,” Nature Physics 11, 173 (2015). [10] Daniel T. Casey et al., “Thermonuclear reactions probed at stellar-core conditions with laser-based inertial-confinement fusion,” Nature Physics 13, 1227 (2017). [11] D. B. Sayre et al., “Measurement of the T + T neutron spectrum using the NIF,” Physical Review Letters 111, 052501 (2013).

[12] A.B. Zylstra et al., “Using inertial fusion implosions to measure the T + 3He fusion cross section at nucleosynthesis – relevant energies,” Physical Review Letters 117, 035202 (2016). [13] A.B. Zylstra et al., “Proton spectra from 3He + T and 3He + 3He fusion at low center-of-mass energy, with potential implications for solar fusion cross sections,” Physical Review Letters 119, 222701 (2017). [14] M. Gatu Johnson et al., “Development of an inertial confinement fusion platform to study charged-particle- producing nuclear reactions relevant to nuclear astrophysics,” Physics of Plasmas 24, 041407 (2017).

Discovery of enhanced recombination in astrophysical environments and the implications for plasma diagnostics

A. Nemer1, N. C. Sterling2, J. Raymond3, A.K. Dupree3 J. García-

Rojas4,5, Qianxia Wang,1,6, M.S. Pindzola1, C. P. Ballance7, and S.D. Loch1 

1 Auburn University, Auburn, AL. 2University of West Georgia, Carrollton, GA. 

3 Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA. 4 Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain. 

5 Universidad de La Laguna, Dpto. Astrofísica, La Laguna, Tenerife, Spain. 6 Department of Physics and Astronomy, Rice University, Houston, TX

7 Queen’s University of Belfast, Belfast, UK.

There are two main types of photoionized gaseous nebulae that exist in the universe: H II regions and Planetary Nebulae (PNe) [1]. These nebulae mark the endpoints of stellar evolution and understanding their composition will lead to a better understanding of stellar evolution processes, galactic chemical nucleosynthesis, and the evolution of the universe as a whole. Elemental abundances are estimated through photo-ionization codes that include all relevant atomic processes for the plasma. Robicheaux et al. [2] proposed that the mechanism of Dielectronic Recombination (DR) which typically occurs in plasma through free electrons would extend to Rydberg states transitioning to below threshold doubly excited states. We call this process Rydberg Enhanced Recombination (RER) and it is currently not considered in modeling codes. We investigate the implications of this new process, while also searching for observational evidence of the mechanism in astrophysical spectra. In this work we present the first evidence of RER through observed optical spectra from eight PNe, and UV spectra of Symbiotic binaries. We use Cloudy simulations to investigate the effects of RER on charge state balance and temperature in PNe, finding that it can make significant changes to both. [1] M. Peimbert, A. Peimbert, and G. Delgado-Inglada, “Nebular spectroscopy: A

guide on HII regions and planetary nebulae,” Publ. Astron. Soc. Pacific, vol. 129, no. 978, 2017.

[2] F. Robicheaux, S. Loch, M. Pindzola, and C. Ballance, “Contribution of Near Threshold States to Recombination in Plasmas,” Phys. Rev. Lett., vol. 105, no. December, p. 233201, 2010.

Fission and Lanthanide Production in r-process Nucleosynthesis

N. Vassh1, M. R. Mumpower2, R. Surman1, G. C. McLaughlin3, and R. Vogt4,5

1University of Notre Dame 2Los Alamos National Laboratory 3North Carolina State University

4Lawerence Livermore National Laboratory 5University of California, Davis

The observations of the GW170817 electromagnetic counterpart suggested lanthanides were produced in this neutron star merger event. Lanthanide production in heavy element nucleosynthesis is subject to large uncertainties from nuclear physics and astrophysics unknowns. Specifically, the rare-earth abundance peak, a feature of enhanced lanthanide production at A~164 seen in the solar r-process residuals, is not robustly produced in r-process calculations. The proposed dynamical mechanism of peak formation requires the presence of a nuclear physics feature in the rare-earth region which may be within reach of experiments performed at, for example, the CPT at CARIBU and the upcoming FRIB. To take full advantage of such measurements, we employ Markov Chain Monte Carlo to "reverse engineer" the nuclear masses capable of producing a peak compatible with the observed solar r-process abundances and compare directly with experimental mass data [1]. Here I will present our latest results and demonstrate how the method may be used to the learn which astrophysical conditions are consistent with both observational and experimental data. Uncertainties in the astrophysical conditions also make it difficult to know if merger events are responsible for populating the heaviest observed nuclei, the actinides. Here I will discuss a potential direct signature of actinide production in merger environments [2]. However, an r process which reaches the actinides is also likely to host fission, which is largely experimentally uncharted for neutron-rich nuclei [3]. The influence of fission on lanthanide abundances, and the potential for future experimental and theoretical efforts to refine our knowledge of fission in the r process, will be discussed. The question of where nature primarily produces the heavy elements can only be answered through such collaborative efforts between experiment, theory, and observation. [1] R. Orford, N. Vassh, et al, Phys. Rev. Lett. 120, 262702 (2018). [2] Y. Zhu, et al, ApJL 863, L23 (2018). [3] N. Vassh et al, accepted to J. Phys. G (2019), arXiv:1810.08133.

Heavy-Element Nucleosynthesis

Bradley S. Meyer1

1Department of Physics and Astronomy, Clemson University, Clemson, SC 29634-0978 Nuclear reactions in the first minutes and hours of the universe produced hydrogen, helium, and trace amounts of lithium, beryllium, and boron. Stars acting over the subsequent roughly ten billion years produced the other elements found in nature. The elements with atomic number less than or roughly equal to that of iron were made in mainline, stable phases of stellar burning. The heavier elements were dominantly made in neutron-capture processes either in helium-burning phases in stellar shells (the slow neutron-capture pro-cess) or in explosive nucleosynthesis in supernovae or neutron star merger events (the rapid neutron-capture process) (e.g., [1]). This talk will review these principal processes of nu-cleosynthesis of elements heavier than iron and the chemical environment in which those elements were likely ejected into the interstellar medium. It will also cover some minor, less well-known stellar nucleosynthesis processes responsible for modifying pre-existing abundances of heavy elements, namely, the gamma process and neutron-burst nucleosyn-thesis. Finally, it will also present some open-source software and other resources for stud-ying heavy-element nucleosynthesis [2]. [1] Meyer, B. S. (1994) Ann. Rev. Astron. Astrophys. 32, 153-190. [2] See: http://sourceforge.net/u/mbradle/blog

The LIGO project: Au and Pt ions for neutron star merger opacities+

Brendan M McLaughlin1

1Centre for Theoretical Atomic, Molecular and Optical Physics (CTAMOP), School of Mathematics and Physics,

Queens University of Belfast, Belfast BT7 1NN, UK

The astrophysical origin of heavy Z elements remains an open question. Spectroscopy of neutron star merger ejecta provides a new opportunity to directly probe regions where heavy elements may be forming, as a result of active r-process nucleosynthesis. As seen from the NIST tabulations, laboratory or theoretical atomic data is scare, even for low charge states of heavy Z elements. In this talk I will address the atomic structure (energy levels, oscillator strengths/transition probabilities) and the photoionization cross section data for the Au and Pt sequences. Data from these atomic processes are required to calculate the Roseland mean opacity. The opacity is defined as a quantity which determines the transport of radiation through matter [1]. The GRASP code [2] is used to perform large-scale atomic structure calculations. In the case of our radiative dynamical studies for these sequences, we utilize the parallel DARC codes [3] running efficiently on high performance computers [4], to obtain the necessary photoionization cross sections. Results will be presented for the heavy elements; Au I, Au II, Au III, AIV and Pt I, Pt II, Pt III, Pt IV. Our large-scale structure and photoionization cross section results are compared (where available) with prior results, recent measurements from the Advanced Light Source (ALS) radiation facility in Berkeley, California and configuration averaged distorted wave (CADW) calculations [5] +This work was supported by NSF grant 1815932. References [1] Seaton M J 1987 J. Phys. B: At. Mol. Opt. Phys. 20 6363 [2] Dyall K G, Johnson C T, Grant I P, Parpia F, and Plummer E P 1989 Comput. Phys. Commun. 55 425 [3] DARC codes, URL http://connorb.freeshell.org [4] McLaughlin B M, Ballance C P, Pindzola M S, Stancil P C, Babb J F, Schippers S and Mueller A 2019 PAMOP2: Towards Exascale Computations Supporting Experiments and Astrophysics, High Performance Computing in Science and Engineering '18 Transactions of the High Performance Computing Center, Stuttgart (HLRS) 2018, ed Nagel W E, Kroener D H and Resch M M (Cham Heidelberg New York Dordrecht London: Springer International Publishing) Chpt.3 [5] Pindzola M S, private communication (2019)

Spectroscopy of multicharged heavy atoms for element formation identification

J. P. Marler1, S. J. Bromley1, C.E. Soslik1, C. A. Johnson2, D. A. Ennis2, S. D. Loch2, M. Pindzola2, P. C. Stancil3, B. M. McLaughlin4

1Clemson University, Clemson, SC 2Auburn University, Auburn, AL

3University of Georgia, Athens, GA 4Queen’s University, Belfast, Ireland

The astrophysical origin of the heavy elements (masses greater than Rb) remains an open question. A new opportunity to directly probe regions where heavy elements may have formed, specifically as a result of active r-process nucleosynthesis, is provided by recent measurements of spectroscopy of neutron star merger ejecta. Optical and infrared spectra of the recent neutron star merger heralded by the first observation of a gravitational wave were obtained by an armada of ground- and space-based telescopes. However, laboratory spectroscopic data on the vast range of heavy elements are so severely limited that emission models are only in qualitative agreement with the observed spectra. Recent experimental results by our group for the electronic structure of singly to triply-charged gold atoms, obtained at the Compact Toroidal Hybrid plasma experiment at Auburn University provide insight into the astrophysically observed spectra. Future experiments at the Clemson University Electron Beam Ion Trap will provide much needed data for even higher charge states.

+This work was supported by USDOE grant DE-FG02-00ER54610 and NSF grant 1815932.

X-ray emission measurements following charge exchange with atomic H using merged beams

A. Roy1, C. Ambarish1, D. Wulf1, F. Jaeckel1, D. McCammon1, D.G. Seely2, V. M. Andrianarijaona3, R. T. Zhang4, C. C. Havener4

1Dep. of Physics, University of Wisconsin, Madison, WI 53706 2Dep. of Physics, Albion College, Albion, MI49224

3Dep. of Physics, Pacific Union College, Angwin, CA 94508 4Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831

A novel experiment to study X-ray emission following charge exchange between highly charged ions and atomic hydrogen is currently in progress using the University of Wisconsin and Goddard Space Flight Center X-ray quantum micro calorimeter detector (XQC). Ions present in the solar wind and planetary exospheres can be generated by an ECR ion source at Oak Ridge National Laboratory (ORNL) and merged with a neutral H beam spanning six orders of magnitude in collision energy. The (n,l) distributions of the captured electron with atomic H as a target is the remaining elusive benchmark for modeling of CX processes. Our measurements on Balmer series line ratio with Ne[IX] + He are compared to ratios constructed from Multi-channel Landau-Zener (MCLZ) calculations [1], which used to produce atomic data needed to characterize X-ray emissions from a variety of astrophysical objects. The measured line ratios are in excellent agreement with the calculations for the 4s → 4p emission, also they indicate an increasing state-selectivity for the 4d and 4f states. Details of the apparatus design with initial low background spectra will also be presented.

[1] D. Lyons, R. S. Cumbee, and P. C. Stancil, Astrophys. J 232, 27 (2017).

Atomic Collisions that shape the light of the universe: latest developments in Cloudy

F. Guzman

University of Kentucky, Lexington, KY

Cloudy is a Spectral simulation code widely used in astrophysics. Cloudy is developed interactively with, and in response to the necessities of the astronomical community. Cloudy deals with the atomic and molecular physical processes that emit and absorb light in astrophysical plasmas to self- consistently calculate the final emitted spectrum. The complexity and big number of processes involved presents a computational and a theoretical challenge. I shall discuss latest advances in atomic physics in the spectral code Cloudy, as well as ongoing development that should be of interest to observers and modelers alike. One of the most significant changes has been the export of atomic and ionic data sets to external data bases, Chianti and Stout. This enables Cloudy to compute spectra with much more rigor and detail than was previously possible. The treatment of the correction of the isotropic radiation fields and optical depths have been greatly improved. In addition, the atomic data for the H-like and He-like iso-sequences have undergone major review. The recent assessment of collisional data on iso- sequence hydrogen- and helium-like ions will permit the accurate modeling of optical and radio recombination line spectrum. Other ongoing efforts will enable Cloudy to compute spectra of discontinuous shocks, such as those produced by supernovae.

Uncertainties in R-matrix Scattering Calculations. Converged Expansions? and, Convergence to what?

Manuel Bautista1

1Department of Physics, Western Michigan University, Kalamazoo, MI 49008

The new era of multi-messenger astronomy open the possibility to study a large variety of physical phenomena previously inaccessible to us. These new science also posse new demands for reliable atomic and molecular data, including data for heavy (trans-iron) atoms and ions and molecular species. Such systems are orders of magnitude more complex than the lighter atoms we generally treated. Thus, multi-configuration treatments of the new systems of interest ought comparatively much more limited, given present computational capabilities. This begs the question, how accurately can we describe such systems?

To attempt to answer the question above we look at different sources of uncertainty in R-matrix scattering calculations. These include truncation uncertainties set by the size of the close coupling expansion and errors from the radial and angular properties of the target basis-set. We show that the quality of the of the basis-set is determinant on the ultimate accuracy of the results. For a given basis-set close coupling expansions reach a point of negative returns with increasing expansion size. Further, we are developing a method to estimate the uncertainties in the uncertainties in resonance positions and widths in cross sections, which are the dominant sources of errors in scattering transition rates.

Lab Astro for Stellar Spectroscopy in the Multi-messenger Era

J. E. Lawler1, C. Sneden2, E. A. Den Hartog1, and J. J. Cowan3

1 Dept. of Physics, Univ. of Wisconsin – Madison, Madison, WI 53706 2Dept. of Astronomy and McDonald Observatory, Univ. of Texas, Austin, TX 78712

3Homer L. Dodge Dept. of Physics & Astronomy, Univ. of Oklahoma, Norman, OK 73019

The 2017 observation of a n(eutron)-star merger by the LIGO/VIRGO and Fermi-LAT collaborations as well as a long list of ground based astronomical teams [1] will likely be remembered as the grand beginning of Multi-messenger Astronomy. This event is surely the first confirmed r(apid)-process n-capture nucleosynthesis event. Naturally these observations lead to many suggestions that n-star mergers were the dominant or perhaps even only r-process site. Such suggestions are premature. Astronomers have been searching for the r-process site(s) since the mechanism was identified many decades ago as the source of about half of heavy (beyond the Fe-group) isotopes [2]. Progress in Lab Astro [e.g. 3] and many observations [e.g. 4] on old, metal-poor (MP) stars has revealed a r-process abundance pattern that is stable across space and time and was robust when the Universe was young. The Lab Astro progress was made by using time-resolved laser-induced-fluorescence to measure accurate absolute radiative lifetimes and combining those with emission branching fractions to determine atomic transition probabilities with small uncertainties. The observations on MP stars were boosted with the increasing availability of large ground based and orbiting telescopes such as the Hubble Space Telescope with high-resolution spectrometers. The initial burst of r-process nucleosynthesis observed in some MP stars is difficult to reconcile with n-star mergers. Models that predict the creation of a large number of n-star binaries with small separation very early in the evolution of the Universe appear to be too contrived. The first generation of stars were likely short-lived and massive with rapid rotation. These Pop III stars, which are thought to be the source of Long Gamma Ray Bursts observed today, are very different than stars undergoing core-collapse in our local Universe. There are other options for making r-process isotopes [e.g. 5, 6]. [1] Abbott, B. P., et al. 2017 "Gravitational Waves and Gamma Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A”, ApJL, 848, L12. [2] Burbidge, M., Burbidge, G., Fowler, W. A., and Hoyle, F., 1957 ."Synthesis of the Elements in Stars”, RMP 29, 547 [3] Lawler, J. E., C. Sneden, C. Cowan, J. J. Ivans, and I. I. Den Hartog, E. A. 2009, “Improved Laboratory Transition Probabilities for Ce II, Application to the Cerium Abundances of the Sun and Five r-Process Rich, Metal-Poor Stars, and Rare Earth Lab Data Summary”, ApJS 182, 51. [4] Sneden, C., Lawler, J. E., Cowan, J. J., Ivans, I. I., and Den Hartog, E. A. 2009, “Rare Earth Element Abundance Distributions for the Sun and Five r-Process-Rich Very Metal-Poor Stars”, ApJS. 182, 80 [5] Cowan, J. J., Sneden, C., Lawler, J. E., Aprahamian, A., Wiescher, M., Martínez-Pinedo, G., Langanke, K., and Thielemann, F-K 2019, “Making the Heaviest Elements in the Universe: A Review of the Rapid Neutron Capture Process” RMP, submitted. [6] Metzger, B. D., Thompson, T. A., and Quataert, E. 2018, “A Magnetar Origin for the Kilonova Ejecta in GW170817”, ApJ 856, 101

The Window Is Open! The Cosmic Laboratory Of LIGO-Virgo Gravitational-wave

Observations

James Clark

Georgia Tech University While the LIGO and Virgo collaborations were still reeling from the excitement of a summer of binary black hole merger observations, the transient astronomy community was rocked by the cataclysmic blast of electromagnetic and gravitational radiation from the fortuitously nearby collision of a pair of neutron stars. This multi-messenger event precipitated one of the largest astronomical follow-up campaigns, if not the largest, in history and the multi-wavelength electromagnetic observations, gravitational wave inferences and even joint searches for high energy neutrinos from this single event continue to provide a vast playground to probe Cosmology, nuclear physics and the mechanisms for gamma-ray bursts. The third LIGO-Virgo observing run began on April 1st this year with the detectors operating at unprecedented sensitivity. In the past six weeks, a number of new gravitational wave detection candidates have been reported in low-latency to the astronomical community. Many of these detection candidates exhibit the now familiar signature of binary black hole mergers and, in some, there is evidence for the collision of neutron stars. Truly, the gravitational-wave window is open! In this talk, I will describe the current status of observations and I will review the results and their astrophysical implications from the previous LIGO-Virgo observing runs.

Multi-Messenger Astrophysics and Time Domain Astronomy

Dieter H. Hartmann

Clemson University, Department of Physics and Astronomy Multi-messenger Time-Domain astrophysics is not a new concept, but the discovery of a short Gamma-Ray Burst following a gravitational wave event on Aug 17, 2017 widely opened this window into the Universe. Transient phenomena require unique observational capabilities to reveal the underlying nature of the system, involving all-sky monitoring, rapid pointing of telescopes, fast and accurate localization and dissemination of positions for coordinated follow-up by globally distributed observatories. We discuss two classes of Gamma-Ray Bursts (GRBs) in view of their multi-messenger signatures. We survey the wider landscape of transients with an eye on upcoming observational facilities. In particular, we describe the search for electromagnetic counterparts of gravitational wave events with the proposed Transient Astrophysical Probe (TAP) mission, and connect to crucial complementary advances needed in Laboratory Astrophysics.

Molecular data for astrophysical hydrogen plasma modeling

M. C. Zammit1, J. Colgan1, D. P. Kilcrease1, C. J. Fontes1, P. Hakel1, J. Leiding1,

E. Timmermans1, L. H. Scarlett2, J. K. Tapley2, J. S. Savage2, D. V. Fursa2, and I. Bray2

1Los Alamos National Laboratory, Los Alamos, United States

2Curtin University, Perth, Australia

Low-temperature hydrogen plasmas are ubiquitous throughout the Universe. They exist

in solar atmospheres, planetary atmospheres, primordial gas clouds, protostars, and

determined much of the chemistry of the early Universe. To model these plasmas in local

thermodynamic equilibrium (LTE) and non-LTE requires the constituents transition cross

sections or rate coefficients to calculate populations (for non-LTE plasmas), opacities,

emissivities and power losses.

Recently we have embarked on the projects of calculating electron- and photon-

molecule data of diatomics utilizing first-principle approaches [1-4]. Here we present a

wide-variety of results required to model LTE and non-LTE molecular hydrogen plasmas,

including electron- and photon-molecule cross sections, rate coefficients and the

molecular emission spectra of LTE plasmas at various temperatures.

To model electron-molecule collisions we have developed the molecular

convergent close-coupling (MCCC) method [1-3]. Results from these studies are the first

of their kind: calculating vibrationally resolved cross sections over a broad range of

impact energies and explicitly demonstrating convergence of the cross sections.

Generally, the results are in good agreement with experiments, however, for some

important processes large discrepancies are seen with generally “accepted” and used data.

Subsequent new experiments have confirmed the MCCC predictions [5].

For the photon-molecule project, we have recently developed a self-consistent

first-principle approach with the goal of calculating comprehensive opacity tables that are

accurate across the entire range of temperature space, from molecular dominated

opacities through to ion dominated opacities. We have calculated cross sections, rate

coefficients and the emission spectra of H2+ [4] and H2, as well as investigated isotopic

effects and the effect of including electronically excited states in the emission

calculations.

[1] M. C. Zammit et al. Phys. Rev. Lett. 116, 233201 (2016).

[2] M. C. Zammit et al. Phys. Rev. A 95, 022708 (2017).

[3] M. C. Zammit et al. Phys. Rev. A 90, 022711 (2014).

[4] M. C. Zammit et al. Astrophys. J. 851, 64 (2017).

[5] M Zawadzki et al. Phys. Rev. A 98, 062704 (2018).

Charge Exchange in Bare Ion Interactions with Hydrogen and Helium Atoms

M. S. Pindzola1, M. Fogle1, P.C. Stancil2, J. P. Marler3

1Auburn University, Auburn, AL 2University of Georgia, Athens, GA 3Clemson University, Clemson, SC

The discovery of highly charged atomic ions in the solar wind and their interaction with interstellar and planetary atoms has renewed interest in accurate charge exchange data in the astrophysical community. A time-dependent lattice method has been used to calculate state selective charge transfer cross sections for C+6 and O+8 collisions with H and He atoms[1,2]. Using standard radiative transition rates, Lyman line ratios are calculated to interpret astrophysical observations. We are currently investigating Mg+12 collisions with H and He atoms and with H2 molecules in support of Clemson CUEBIT experiments.

[1] M. S. Pindzola and M. Fogle, J. Phys. B 48, 205203 (2015).��

[2]M. S. Pindzola, M. Fogle, and P. C. Stancil, J. Phys. B 51, 065204 (2018). �

Comprehensive atomic data for singly-ionized iron-group elements

Gillian Nave1, Hala1, Jacob W. Ward1, Juliet C. Pickering2, Florence S. Liggins2, Christian Clear2, Marie Teresa Belmonte Sainz-Ezquerra2

1National Institute of Standards & Technology, Gaithersburg, MD

2Imperial College London, United Kingdom The high cosmic abundance and rich spectra of iron-group elements mean that they are important contributors to the spectra of a wide variety of objects. Iron-group elements are so dominant in the spectra of many A and B-type stars that it is nearly impossible to perform an abundance analysis of any other element without accurate atomic data for iron group elements. Even high-excitation energy levels, which give rise to few spectral lines in laboratory atomic spectra, can be of importance in interpreting stellar spectra. In order to understand these spectra, it is thus necessary to obtain and analyze high-resolution, high signal-to-noise ratio laboratory spectra over the whole wavelength region from the vacuum ultraviolet to the near infrared, to derive accurate wavelengths and energy levels for all of the neutral and singly-ionized elements from scandium through nickel. Several years ago, the atomic spectroscopy groups at the National Institute of Standards and Technology (NIST) and Imperial College London (ICL) joined forces for a concerted effort to improve the database of neutral, singly-ionized, and doubly-ionized iron-group elements [1]. We initially focused on wavelengths, energy levels, and hyperfine structure constants, measured using high-resolution Fourier transform (FT) and grating spectrometers at NIST and ICL. As a result of this effort, we have decreased the uncertainties of the singly-ionized iron elements by an order of magnitude and increased the number of known lines by factors of two to five. The combined wavelength region of our measurements extends from 82 nm to 5000 nm and covers the region of almost all of the allowed lines of astrophysical interest from these elements. More recently we have been collaborating with the University of Wisconsin-Madison program to measure oscillator strengths in the ultraviolet for the analysis of metal-poor stars. The uncertainties in these oscillator strength measurements are now dominated by the branching fractions rather than the lifetimes, particularly when lines used for abundance measurements are widely separated in wavelength from the dominant lines from the upper level of the transition. We are now extending these measurements to the vacuum ultraviolet, where few oscillator strengths have been measured, focusing initially on the spectra of Fe II and Cr II. [1] G. Nave, C. J. Sansonetti, K. Townley-Smith, J. C. Pickering, A. P Thorne, F. Liggins & C. Clear, Can. J. Phys. 95, 811 (2017).

Ion induced electron emission from ices and hydrated metal surfaces

J.L. Shinpaugh, E.C. Maertz, W.L. Hawkins, R.A. McLawhorn, L.H. Toburen, and M. Dingfelder

Department of Physics, East Carolina University, Greenville, NC 27858

Recent experimental and theoretical results for energy deposition and electron emission from water and hydrocarbon ices induced by fast ion impact are presented. The experiments were conducted at the ion beam facility at East Carolina University using the 2 MV Pelletron accelerator for protons and carbon ions in the energy range of 1 – 6 MeV, and for higher energies at the J.R. Macdonald Laboratory at Kansas State University. Absolute doubly differential electron emission yields were measured from thin films of hydrocarbons and water ice (amorphous solid water) condensed on a cryogenic substrate induced by fast ion impact; representative spectra are shown in Figure 1. In addition, absolute yields from water ice are compared to results from the PARTRAC Monte Carlo track structure simulation code for electron transport in liquid water. The model calculations work well for higher emitted electron energies (i.e., >50 eV) but overestimates the yields of low-energy electrons, which are important for microdosimetry calculations. [1]

Figure 1: Electron emission spectra for 6-MeV protons traversing 200 monolayers of water ice condensed on 1-μm copper foil at 40K for various emission angles. While earlier atomic collisions experiments at ECU focused primarily on ion-atom and ion-molecule interaction processes for gas-phase targets, current experiments have focused on fast-ion induced energy deposition and electron transport in condensed-phase targets (ices) and metal surfaces. Over the last decade, the primary application for these studies has been for modelling radiation dosimetry in biologic systems; however, other applications, such as for modelling astrophysical environments, may exist. An overview of current experimental capabilities for atomic collisions experiments will be presented. [1] L.H. Toburen, S.L. McLawhorn, R.A. McLawhorn, K.D. Carnes, M. Dingfelder and J.L. Shinpaugh, Radiation Research 174, 107 (2010).

“Universal” theoretical approach for determination of cross sections for dissociative recombination, rotational, vibrational, electronic excitation

of molecular ions.

V. Kokoouline

Department of Physics, University of Central Florida, Orlando, Florida

Plasma at relatively low temperatures, a few eV and below, contains not only atomic, but also molecular ions. This is the reason why molecular ions play an important role in plasma properties, its evolution and decay at low temperatures. Thus, it is important to take the molecular ions into account when one deals with low-temperature atomic plasma. Depending on the temperature, electronic (for T<10 eV), vibrational (T<1 eV), or rotational (T<0.0.5 eV) structure of the molecular ions should be accounted for to describe the behavior of the plasma. Measuring cross sections for different processes involving the molecular ions is difficult, especially because dozens or even hundreds processes should be taken into account for a reasonable modeling of plasma. In this situation, plasma modeling should rely on theoretical approaches for determination of properties and cross sections of species present in molecular plasma.

It this talk, I will describe different theoretical techniques developed during the last decade to compute cross sections for different processes involving electron-molecule collisions: dissociative recombination, rotational, vibrational, electronic excitation of molecular ions, dissociative electron attachment to neutral molecules, radiative processes in electron-molecule collisions.

Heavy Atoms and the Heliosphere driven by Charge-Exchange

Anthony M. DeStefano1

1University of Alabama in Huntsville, Space Science Department The heliosphere is a cavity carved out of the interstellar medium by the supersonic outflow of solar wind from the Sun. The local interstellar medium is partially ionized with the neutral particles penetrating the heliosphere unimpeded by the electric and magnetic fields. Throughout these plasmas, the main constituents are protons and electrons. However, heavy atoms are present in smaller amounts with helium as the next most significant component of the plasma in addition to oxygen and neon. There is strong evidence that NASA’s Interstellar Boundary Explorer (IBEX) has observed energetic neutral atoms (ENAs) of helium [1], oxygen, and neon [2] originating from just outside the heliosphere, called the outer heliosheath. The driving mechanism that dominates ENA generation is thought to be charge-exchange, not only in the heliosphere but in planetary magnetosheaths as well. The importance of charge-exchange will be discussed and how heavy atoms play a role in heliospheric dynamics. [1] Bzowski, M., Kubiak, M.A., Czechowski, A. and Grygorczuk, J., 2017. The Helium Warm Breeze in IBEX Observations As a Result of Charge-exchange Collisions in the Outer Heliosheath. The Astrophysical Journal, 845(1), p.15. [2] Park, J., Kucharek, H., Möbius, E., Galli, A., Livadiotis, G., Fuselier, S.A. and McComas, D.J., 2015. Statistical analysis of the heavy neutral atoms measured by IBEX. The Astrophysical Journal Supplement Series, 220(2), p.34.

X-ray Absorption Models for Interstellar O, Si, and Fe: Atomic vs. Molecular/Solid-State Absorbers

Thomas W. Gorczyca1, Manuel A. Bautista1, Javier Garcia2, Connor P. Ballance3, and

Timothy R. Kallman4

1 Western Michigan University 2 California Institute of Technology

3Queen’s University, Belfast 4NASA Goddard Space Flight Center

X-ray absorbers in the interstellar medium can be found as both atomic gas, but also as molecular gas or as dust (e.g., silicate or ice particles). Spectral models of the rich resonant absorption features near inner-shell thresholds can reveal the elemental abundances and chemical forms, but require photoabsorption data not only for atomic systems, but also for molecular or solid-state absorbers. This talk will review the status of data available for spectral modeling codes, particularly the XSTAR code, which relies on the ISMabs photoabsorption database. Results from recent R-matrix calculations for atomic oxygen are first presented, along with the final spectral model, indicating that X-ray spectra from Chandra, for instance, can be modeled assuming only atomic ISM oxygen. New R-matrix results for atomic silicon and iron, near their K- and L-shell edges, respectively, are also presented. For these heavier systems, the observed inner-edge Chandra spectra indicate mostly solid-state form, and the atomic contribution seems unimportant. In an attempt to treat molecular and solid-state absorption calculations in a similar fashion, we are developing two lines of approach, as will be discussed in the talk. First, since the atomic cross section is routinely fit using a quantum defect theory-like approach for producing analytical expressions of the inner-shell Rydberg series photoabsorption cross sections, this resultant atomic expression can be modified to consider the effects of neighboring atoms. The fitting modifications preserve two of the important features of inner-shell Rydberg absorption spectra: 1) adherence to the Thomas-Reiche-Kuhn oscillator strength sum rule, and 2) independence of the elemental form on the asymptotic background cross sections (away from threshold). The modifications are based on physical considerations of continuum lowering due to multiple atomic potentials.

The second development to be discussed is the direct theoretical computation for molecular photoabsorption, using the UKRMol suite of codes, which are based on the atomic Belfast R-matrix codes, and also for solid-state photoabsorption, using multiple scattering theory via the Fermi model of perturbed atomic scattering. The ultimate astrophysical relevance of this work is to help answer the open question: where are oxygen, silicon, and iron found in the universe and in what abundances and physical and chemical forms?