Astrophysics and Astronomy Commons^™

The Power Of Principled Bayesian Methods In The Study Of Stellar Evolution, Ted Von Hippel, David Van Dyk, David Stenning, Elliot Robinson, Elizabeth Jeffery, Nathan Stein, William Jefferys, Erin M. O'Malley

Publications

It takes years of effort employing the best telescopes and in- struments to obtain high-quality stellar photometry, astrometry, and spectroscopy. Stellar evolution models contain the experience of life- times of theoretical calculations and testing. Yet most astronomers fit these valuable models to these precious datasets by eye. We show that a principled Bayesian approach to fitting models to stellar data yields substantially more information over a range of stellar astrophysics. We highlight advances in determining the ages of star clusters, mass ratios of binary stars, limitations in the accuracy of stellar models, post-main-sequence mass loss, and the ages of individual …

Bayesian Analysis For Stellar Evolution With Nine Parameters (Base-9): User's Manual, Ted Von Hippel, Elliot Robinson, Elizabeth Jeffery, Rachel Wagner-Kaiser, Steven Degennaro, Nathan Stein, David Stenning, William H. Jefferys, David Van Dyk

Publications

BASE-9 is a Bayesian software suite that recovers star cluster and stellar parameters from photometry. BASE-9 is useful for analyzing single-age, single-metallicity star clusters, binaries, or single stars, and for simulating such systems. BASE-9 uses Markov chain Monte Carlo and brute-force numerical integration techniques to estimate the posterior probability distributions for the age, metallicity, helium abundance, distance modulus, and line-of-sight absorption for a cluster, and the mass, binary mass ratio, and cluster membership probability for every stellar object. BASE-9 is provided as open source code on a version-controlled web server. The executables are also available as Amazon Elastic Compute Cloud …

Measuring The Shock-Heating Rate In The Winds Of O Stars Using X-Ray Line Spectra, David H. Cohen, Zequn Li , '16, K. G. Gayley, S. P. Owocki, J. O. Sundqvist, V. Petit, M. A. Leutenegger

Physics & Astronomy Faculty Works

We present a new method for using measured X-ray emission line fluxes from O stars to determine the shock-heating rate due to instabilities in their radiation-driven winds. The high densities of these winds means that their embedded shocks quickly cool by local radiative emission, while cooling by expansion should be negligible. Ignoring for simplicity any non-radiative mixing or conductive cooling, the method presented here exploits the idea that the cooling post-shock plasma systematically passes through the temperature characteristic of distinct emission lines in the X-ray spectrum. In this way, the observed flux distribution among these X-ray lines can be used …

The Optical Luminosity Function Of Gamma-Ray Bursts Deduced From Rotse-Iii Observations, X. H. Cui, X. F. Wu, J. J. Wei, F. Yuan, W. K. Zheng, E. W. Liang, C. W. Akerlof, M. C. B. Ashley, H A. Flewelling, E. Göǧüş, T. Güver, Ü. Kızıloǧlu, T. A. Mckay, S. B. Pandey, E. S. Rykoff, W. Rujopakarn, B. E. Schaefer, J. C. Wheeler, Sarah A. Yost

Physics Faculty Publications

We present the optical luminosity function (LF) of gamma-ray bursts (GRBs) estimated from a uniform sample of 58 GRBs from observations with the Robotic Optical Transient Search Experiment III (ROTSE-III). Our GRB sample is divided into two sub-samples: detected afterglows (18 GRBs) and those with upper limits (40 GRBs). We derive R-band fluxes for these two sub-samples 100 s after the onset of the burst. The optical LFs at 100 s are fitted by assuming that the co-moving GRB rate traces the star formation rate. While fitting the optical LFs using Monte Carlo simulations, we take into account the …

Recoiling Supermassive Black Holes: A Search In The Nearby Universe, Davide Lena, Andrew Edward Robinson, Alessandro Marconi, David J. Axon, Alessandro Capetti, David Merritt, Daniel P. Batcheldor

Aerospace, Physics, and Space Science Faculty Publications

The coalescence of a binary black hole can be accompanied by a large gravitational recoil due to anisotropic emission of gravitational waves. A recoiling supermassive black hole (SBH) can subsequently undergo long-lived oscillations in the potential well of its host galaxy, suggesting that offset SBHs may be common in the cores of massive ellipticals. We have analyzed Hubble Space Telescope archival images of 14 nearby core ellipticals, finding evidence for small (≲ 10 pc) displacements between the active galactic nucleus (AGN; the location of the SBH) and the center of the galaxy (the mean photocenter) in 10 of them. Excluding …

Ion Composition In Interchange Injection Events In Saturn's Magnetosphere, M. F. Thomsen, Daniel B. Reisenfeld, R. J. Wilson, M. Andriopoulou, F. J. Crary, G. B. Hospodarsky, C. M. Jackman, X. Jia, K. K. Khurana, C. Paranicas, E. Roussos, N. Sergis, R. L. Tokar

Physics and Astronomy Faculty Publications

Interchange injection events are commonly observed by the Cassini spacecraft in the region between about 6 and 12 R_s (1 R_s = 60,268 km) and even frequently beyond. In this study, 13 examples of interchange injection events are identified in Cassini-Cassini Plasma Spectrometer data under special conditions such that time-of-flight (TOF) mass spectra could be obtained from entirely within the events. Using the TOF data to separate the main ion species H⁺, H₂⁺, and W⁺, approximate densities of each species are calculated under the assumption that all distributions were isotropic. The …

Candels/Goods-S, Cdfs, And Ecdfs: Photometric Redshifts For Normal And X-Ray-Detected Galaxies, Li-Ting Hsu, Mara Salvato, Kirpal Nandra, Marcella Brusa, Ralf Bender, Johannes Buchner, Jennifer L. Dooley, Dale D. Kocevski, Yicheng Guo, Nimish P. Hathi, Cyprian Rangel, S. P. Willner, Murray Brightman, Antonis Georgakakis, Tamás Budavári, Alexander S. Szalay, Matthew L.N. Ashby, Guillermo Barro, Tomas Dahlen, Sandra M. Faber, Henry C. Ferguson, Audrey Galametz, Andrea Grazian, Norman A. Grogin, Kuang-Han Huang, Anton M. Koekemoer, Ray A. Lucas, Elizabeth Mcgrath, Bahram Mobasher, Michael Peth, David J. Rosario, Jonathan R. Trump

Physics and Astronomy Faculty Publications

We present photometric redshifts and associated probability distributions for all detected sources in the Extended Chandra Deep Field South (ECDFS). This work makes use of the most up-to-date data from the Cosmic Assembly Near-IR Deep Legacy Survey (CANDELS) and the Taiwan ECDFS Near-Infrared Survey (TENIS) in addition to other data. We also revisit multi-wavelength counterparts for published X-ray sources from the 4 Ms CDFS and 250 ks ECDFS surveys, finding reliable counterparts for 1207 out of 1259 sources (~96%). Data used for photometric redshifts include intermediate-band photometry deblended using the TFIT method, which is used for the first time in …

Defining The Flora Family: Orbital Properties, Reflectance Properties And Age, Melissa J. Dykhuis, Lawrence Molnar, Samuel J. Van Kooten, Richard Greenberg

University Faculty Publications and Creative Works

The Flora family resides in the densely populated inner main belt, bounded in semimajor axis by the ν6 secular resonance and the Jupiter 3:1 mean motion resonance. The presence of several large families that overlap dynamically with the Floras (e.g., the Vesta, Baptistina, and Nysa-Polana families), and the removal of a significant fraction of Floras via the nearby ν6 resonance complicates the Flora family's distinction in both proper orbital elements and reflectance properties. Here we use orbital information from the Asteroids Dynamic Site (AstDyS), color information from the Sloan Digital Sky Survey (SDSS), and albedo information from the Wide-field Infrared …

X-Ray Emission From Magnetic Massive Stars, Y. Nazé, V. Petit, M. Rinbrand, David H. Cohen, S. Owocki, A. Ud-Doula, G. A. Wade

Physics & Astronomy Faculty Works

Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. To clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM-Newton observations, corresponding to all available exposures of known massive magnetic stars (over 100 exposures covering ~60% of stars compiled in the catalog of Petit et al.). We show that the X-ray luminosity is strongly correlated with the stellar wind mass-loss rate, with a power-law form that is slightly steeper than linear for the majority of the less luminous, lower-${\dot{M}}$ B stars and flattens for the …

Separation Of The Ribbon From Globally Distributed Energetic Neutral Atom Flux Using The First Five Years Of Ibex Observations, N. A. Schwadron, E. Moebius, S. A. Fuselier, D. J. Mccomas, H. O. Funsten, Paul H. Janzen, Daniel B. Reisenfeld, H. Kucharek, M. A. Lee, K. Fairchild, F. Allegrini, M. Dayeh, G. Livadiotis, M. Reno, M. Bzowski, J. M. Sokol, M. A. Kubiak, E. R. Christian, R. Demajistre, P. Frisch, A. Galli, P. Wurz, M. Gruntman

Physics and Astronomy Faculty Publications

The Interstellar Boundary Explorer (IBEX) observes the IBEX ribbon, which stretches across much of the sky observed in energetic neutral atoms (ENAs). The ribbon covers a narrow (∼20^◦–50^◦) region that is believed to be roughly perpendicular to the interstellar magnetic field. Superimposed on the IBEX ribbon is the globally distributed flux that is controlled by the processes and properties of the heliosheath. This is a second study that utilizes a previously developed technique to separate ENA emissions in the ribbon from the globally distributed flux. A transparency mask is applied over the ribbon and …

Nasa's Search For Life Beyond The Earth, John W. Delano Prof

Atmospheric and Environmental Science Faculty Scholarship

Invited presentation (November 3, 2014 for the 119th Annual Conference of the Science Teachers Association of New York State) provides an overview of NASA's search for worlds orbiting other nearby stars on the Milky Way galaxy.

The Mass Evolution Of The First Galaxies: Stellar Mass Functions And Star Formation Rates At 4 < Z < 7 In The Candels Goods-South Field, K. Duncan, C. J. Conselice, A. Mortlock, W. G. Hartley, Y. Guo, H. C. Ferguson, R. Davé, Y. Lu, J. Owensworth, M. L. N. Ashby, A. Dekel, M. Dickinson, S. Faber, M. Giavalisco, N. Grogin, Dale D. Kocevski, A. Koekemoer, R. S. Somerville, C. E. White

Physics and Astronomy Faculty Publications

We measure new estimates for the galaxy stellar mass function and star formation rates for samples of galaxies at z ∼ 4, 5, 6 and 7 using data in the CANDELS GOODS South field. The deep near-infrared observations allow us to construct the stellar mass function at z ≥ 6 directly for the first time. We estimate stellar masses for our sample by fitting the observed spectral energy distributions with synthetic stellar populations, including nebular line and continuum emission. The observed UV luminosity functions for the samples are consistent with previous observations; however, we find that the observed M_{UV …}

Single Spin Asymmetries In Charged Kaon Production From Semi-Inclusive Deep Inelastic Scattering On A Transversely Polarized 3He Target, C. Dutta, A. Kolarkar, Wolfgang Korsch, Y. X. Zhao, Y. Wang, K. Allada, K. Aniol, J. R. M. Annand, T. Averett, F. Benmokhtar, W. Bertozzi, P. C. Bradshaw, P. Bosted

Physics and Astronomy Faculty Publications

We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized ³He target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of 0.1<x_bj<0.4 for K⁺ and K⁻ production. While the Collins and Sivers moments for K⁺ are consistent with zero within the experimental uncertainties, both moments for K⁻ favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fit to the …

X-Ray Emission From Magnetic Massive Stars, Yaël Nazé, Véronique Petit, Melanie Rinbrand, David H. Cohen, Stanley P. Owocki, Asif Ud-Doula, Gregg A. Wade

Aerospace, Physics, and Space Science Faculty Publications

Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. To clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM-Newton observations, corresponding to all available exposures of known massive magnetic stars (over 100 exposures covering 60% of stars compiled in the catalog of Petit et al.). We show that the X-ray luminosity is strongly correlated with the stellar wind mass-loss rate, with a power-law form that is slightly steeper than linear for the majority of the less luminous, lower- B stars and flattens for the …

Measurement Of “Pretzelosity” Asymmetry Of Charged Pion Production In Semi-Inclusive Deep Inelastic Scattering On A Polarized 3He Target, K. Allada, C. Dutta, A. Kolarkar, Wolfgang Korsch, Y. Zhang, X. Qian, J. Huang, J. Katich, Y. Wang, K. Aniol, J. R. M. Annand, T. Averett

Physics and Astronomy Faculty Publications

An experiment to measure single-spin asymmetries of semi-inclusive production of charged pions in deep-inelastic scattering on a transversely polarized ³He target was performed at Jefferson Laboratory in the kinematic region of 0.16<x<0.35 and 1.42<2.7 GeV² Pretzelosity asymmetries on ³He, which are expressed as the convolution of the h^⊥_1T transverse-momentum-dependent distribution functions and the Collins fragmentation functions in the leading order, were measured for the first time. Under the effective polarization approximation, we extracted the corresponding neutron asymmetries from the measured ³He asymmetries and cross-section ratios between the proton and ³He. Our results show that both …

Searching For Chemical Signatures Of Multiple Stellar Populations In The Old, Massive Open Cluster Ngc 6791, Angela Bragaglia, Christopher Sneden, Eugenio Carretta, Raffaele G. Gratton, Sara Lucatello, Peter F. Bernath, James S. A. Brooke, Ram S. Ram

Chemistry & Biochemistry Faculty Publications

Galactic open and globular clusters (OCs, GCs) appear to inhabit separate regions of the age-mass plane. However, the transition between them is not easily defined because there is some overlap between high-mass, old OCs and low-mass, young GCs. We are exploring the possibility of a clear-cut separation between OCs and GCs using an abundance feature that has been found so far only in GCs: (anti)correlations between light elements. Among the coupled abundance trends, the Na-O anticorrelation is the most widely studied. These anticorrelations are the signature of self-enrichment, i.e., of a formation mechanism that implies multiple generations of stars. Here …

Model-Independent Plotting Of The Cosmological Scale Factor As A Function Of Lookback Time, H. I. Ringermacher, L. R. Mead

Faculty Publications

In this work we describe a model-independent method of developing a plot of scale factor a(t) versus lookback time t_L from the usual Hubble diagram of modulus data against redshift. This is the first plot of this type. We follow the model-independent methodology of Daly & Djorgovski used for their radio-galaxy data. Once the a(t)data plot is completed, any model can be applied and will display as described in the standard literature. We then compile an extensive data set to z = 1.8 by combining Type Ia supernovae (SNe Ia) data from SNLS3 …

Pulsar J0453+1559, The 10th Double Neutron Star System In The Universe, Jose Guadalupe Martinez

Theses and Dissertations - UTB/UTPA

Pulsars are neutron stars that spin rapidly, are highly magnetized, and they emit beams of electromagnetic radiation like a lighthouse out in space. These beams of radiation are only observed when the beams face towards Earth and can be measured by a radio telescope. Pulsar studies have an abundance of scientific implementations in solid state physics, general relativity, galactic astronomy, astronomy, planetary physics and have even opened windows in cosmology. This thesis reports the results of a study of pulsar (PSR) J0453+1559, a new binary pulsar discovered in the Arecibo All-Sky 327 MegaHertz Drift Pulsar Survey. The recorded observations of …

A Coherent Method For The Detection And Parameter Estimation Of Continuous Gravitational Wave Signals Using A Pulsar Timing Array, Yan Wang, Soumya D. Mohanty, F. A. Jenet

Physics & Astronomy Faculty Publications

The use of a high precision pulsar timing array is a promising approach to detecting gravitational waves in the very low frequency regime (10-6-10-9 Hz) that is complementary to ground-based efforts (e.g., LIGO, Virgo) at high frequencies (∼10-103 Hz) and space-based ones (e.g., LISA) at low frequencies (10-4-10-1 Hz). One of the target sources for pulsar timing arrays is individual supermassive black hole binaries which are expected to form in galactic mergers. In this paper, a likelihood-based method for detection and parameter estimation is presented for a monochromatic continuous gravitational wave signal emitted by such a source. The so-called pulsar …

Spitzer/Infrared Array Camera Near-Infrared Features In The Outer Parts Of S4g Galaxies., Seppo Laine, Johan H. Knapen, Juan Carlos Munoz-Mateos, Taehyun Kim, Sebastien Comeron, Marie Martig, Benne W. Holwerda, E. Athanassoula, Albert Bosma, Peter H. Johansson, Santiago Erroz-Ferrer, Dimitri A. Gadotti, Armando Gil De Paz, Joannah Hinz, Jarkko Laine, Eija Laurikainen, Karin Menendez-Delmestre, Trisha Mizusawa, Michael Regan, Heikki Salo, Kartik Sheth, Mark Seibert, Ronald J. Buta, Mauricio Cisternas, Bruce G. Elmegreen, Debra M. Elmegreen, Luis C. Ho, Barry F. Madore, Dennis Zaritsky

Faculty and Staff Scholarship

We present a catalogue and images of visually detected features, such as asymmetries, extensions, warps, shells, tidal tails, polar rings, and obvious signs of mergers or interactions, in the faint outer regions (at and outside of R25) of nearby galaxies. This catalogue can be used in future quantitative studies that examine galaxy evolution due to internal and external factors. We are able to reliably detect outer region features down to a brightness level of 0.03 MJy sr−1 pixel−1 at 3.6 μm in the Spitzer Survey of Stellar Structure in Galaxies (S4G). We also tabulate companion galaxies. We find asymmetries …

Galaxy And Mass Assembly (Gama) : Galaxy Close Pairs, Mergers And The Future Fate Of Stellar Mass., A. S. G. Robotham, S. P. Driver, L. J. M. Davies, A. M. Hopkins, I. K. Baldry, N. K. Agius, A. E. Bauer, J. Bland-Hawthorn, S. Brough, M. J. I. Brown, M. Cluver, R. De Propis, M. J. Drinkwater, Benne W. Holwerda, L. S. Kelvin, M. A. Lara-Lopez, J. Liske, Angel R. Lopez-Sanchez, J. Loveday, S. Mahajan, T. Mcnaught-Roberts, A. Moffett, P. Norberg, D. Obreschkow, M. S. Owers, S. J. Penny, K. A. Pimbblet, M. Prescott, E. N. Taylor, E. Van Kampen, S. M. Wilkins

Faculty and Staff Scholarship

We use a highly complete subset of the Galaxy And Mass Assembly II (GAMA-II) redshift sample to fully describe the stellar mass dependence of close pairs and mergers between 108 and 1012 M⊙. Using the analytic form of this fit we investigate the total stellar mass accreting on to more massive galaxies across all mass ratios. Depending on how conservatively we select our robust merging systems, the fraction of mass merging on to more massive companions is 2.0–5.6 per cent. Using the GAMA-II data we see no significant evidence for a change in the close pair fraction between redshift z …

Evidence For The Concurrent Growth Of Thick Discs And Central Mass Concentrations From S4g Imaging., S. Comeron, B. G. Elmegreen, H. Salo, E. Laurikainen, Benne W. Holwerda, J. H. Knapen

Faculty and Staff Scholarship

We have produced 3.6 μm + 4.5 μm vertically integrated radial luminosity profiles of 69 edge-on galaxies from the Spitzer Survey of Stellar Structure in Galaxies (S4G). We decomposed the luminosity profiles into a disc and a central mass concentration (CMC). These fits, combined with thin/thick disc decompositions from our previous studies, allow us to estimate the masses of the CMCs, the thick discs, and the thin discs (ℳCMC, ℳT, and ℳT). We obtained atomic disc masses (ℳg) from the literature. We then consider the CMC and the thick disc to be dynamically hot components and the thin …

Book Review: Planetary Rings: A Post-Equinox View 2nd Ed, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Planetary Rings : a Post-Equinox View 2nd Ed. by Larry W. Esposito, Cambridge, 2014 246p bibl index, 9781107028821 $120.00

Small Carbon Chains In Circumstellar Envelopes, R. J. Hargreaves, K. Hinkle, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

Observations of carbon-rich circumstellar envelopes were made using the Phoenix spectrograph on the Gemini South telescope to determine the abundance of small carbon chain molecules. Vibration-rotation lines of the ν3 antisymmetric stretch of C₃ near 2040 cm^-1 (4.902 μm) have been used to determine the column density for four carbon-rich circumstellar envelopes: CRL 865, CRL 1922, CRL 2023 and IRC +10216. We additionally calculate the column density of C₅ for IRC +10216, and provide an upper limit for five more objects. An upper limit estimate for the C₇ column density is also provided for IRC+10216. A …

Investigation Of Waves In The Very Local Interstellar Medium, Parisa Mostafavi

Von Braun Symposium Student Posters

No abstract provided.

Digital Optical Correlator X-Ray Telescope Alignment Tracking System, Tomasz Marek Lis

Von Braun Symposium Student Posters

No abstract provided.

Can We Use The Nasa Gamma-Ray Burst Satellites, Fermi And Swift, To Aid The Search For The First Gravitational Wave Detection?, E Burns

Von Braun Symposium Student Posters

No abstract provided.

Instability And Particle Acceleration In Relativistic Jets, Qiana Hunt, Kyle Rettke

Von Braun Symposium Student Posters

No abstract provided.

Tracing Evolutionary Processes In Stellar Disks In Nearby Dwarf Galaxies From X-Ray Light, Sarthak Dasadia

Von Braun Symposium Student Posters

No abstract provided.

Keck-I Mosfire Spectroscopy Of Compact Star-Forming Galaxies At Z ≳ 2: High Velocity Dispersions In Progenitors Of Compact Quiescent Galaxies, Guillermo Barro, Jonathan R. Trump, David C. Koo, Avishai Dekel, Susan A. Kassin, Dale D. Kocevski, Sandra M. Faber, Arjen Van Der Wel, Yicheng Guo, Pablo G. Pérez-González, Elisa Toloba, Jerome J. Fang, Camilla Pacifici, Raymond Simons, Randy D. Campbell, Daniel Ceverino, Steven L. Finkelstein, Bob Goodrich, Marc Kassis, Anton M. Koekemoer, Nicholas P. Konidaris, Rachel C. Livermore, James E. Lyke, Bahram Mobasher, Hooshang Nayyeri, Michael Peth, Joel R. Primack, Luca Rizzi, Rachel S. Somerville, Gregory D. Wirth, Adi Zolotov

Physics and Astronomy Faculty Publications

We present Keck-I MOSFIRE near-infrared spectroscopy for a sample of 13 compact star-forming galaxies (SFGs) at redshift 2 ≤ z ≤ 2.5 with star formation rates of SFR ~ 100 M _☉ yr^–1 and masses of log(M/M _☉) ~10.8. . . .

For the remainder of the abstract, please visit:

http://dx.doi.org/10.1088/0004-637X/795/2/145