Physical Sciences and Mathematics | Open Access Articles

Validation Of Argon From Underground Sources For Use In The Darkside-50 Detector, Thomas R. Alexander

Masters Theses

Liquid argon is an attractive target for dark matter searches due to its low cost and exemplary event discrimination. However, atmospherically derived argon contains the beta-emitter 39Ar which confounds the growth of dual-phase time projection chamber (TPC) style detectors to the ton-scale. The DarkSide Collaboration seeks to bypass this limitation by extracting argon from deep underground, from a location known to contain significantly less 39Ar than atmospherically derived argon. This thesis will summarize the e orts taken to produce the first batch of underground argon, focusing on the first operation of the underground argon in a dual-phase TPC to validate …

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The Impact Of Terrestrial Noise On The Detectability And Reconstruction Of Gravitational Wave Signals From Core-Collapse Supernovae, Jessica Mciver

Doctoral Dissertations

Among of the wide range of potentially interesting astrophysical sources for gravitational wave detectors Advanced LIGO and Advanced Virgo are galactic core-collapse supernovae. Although detectable core-collapse supernovae have a low expected rate (a few per century, or less) these signals would yield a wealth of new physics. Of particular interest is the insight into the explosion mechanism driving core-collapse supernovae that can be gleaned from the reconstructed gravitational wave signal. A well-reconstructed waveform will allow us to assess the likelihood of different explosion models, perform model selection, and potentially map unexpected features to new physics. This dissertation presents a series …

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An Empirical Approach To Understanding Of Star Formation In Dark Matter Halos, Zhankui Lu

Doctoral Dissertations

We present a data-driven approach to understand the star formation in dark matter halos over cosmic time. With a simple empirical model and advanced tools for Bayesian inference, we try to constrain how galaxies have assembled their stars across cosmic time using stellar mass functions (SMFs) and the luminosity function of cluster galaxies. The key ingredients of the empirical model include dark halo merger trees and a generic function that links star formation rate (SFR) to the host halos. We found a new characteristic redshift z_c ~ 2 above which the SFR in low mass halos < 10¹¹solar mass …

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Gravitational Wave Astrophysics: Instrumentation, Detector Characterization, And A Search For Gravitational Signals From Gamma-Ray Bursts, Daniel Hoak

Doctoral Dissertations

In the coming years, the second generation of interferometric gravitational wave detectors are widely expected to observe the gravitational radiation emitted by compact, energetic events in the nearby universe. The field of gravitational wave astrophysics has grown into a large international endeavor with a global network of kilometer-scale observatories. The work presented in this thesis spans the field, from optical metrology, to instrument commissioning, to detector characterization and data analysis. The principal results are a method for the precise characterization of optical cavities, the commissioning of the advanced LIGO Output Mode Cleaner at the Hanford observatory, and a search for …

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Exact Solutions In Gravity: A Journey Through Spacetime With The Kerr-Schild Ansatz, Benjamin Ett

Doctoral Dissertations

The Kerr-Schild metric ansatz can be expressed in the form $g_{ab} = \gbar_{ab}+\lambda k_ak_b$, where $\gbar_{ab}$ is a background metric satisfying Einstein's equations, $k_a$ is a null-vector, and $\lambda$ is a free parameter. It was discovered in 1963 while searching for the elusive rotating black hole solutions to Einstein's equations, fifty years after the static solution was found and Einstein first formulated his theory of general relativity. While the ansatz has proved an excellent tool in the search for new exact solutions since then, its scope is limited, particularly with respect to higher dimensional theories. In this thesis, we present …

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The Jcmt Gould Belt Survey: Evidence For Radiative Heating In Serpens Mwc 297 And Its Influence On Local Star Formation, D. Rumble, J. Hatchell, R. A. Gutermuth, H. Kirk, J. Buckle, S.F. Beaulieu, D.S. Berry, H. Broekhoven-Fiene, M.J. Currie, M. Fich, T. Jenness, D. Johnstone, J.C. Mottram, D. Nutter, K. Pattle, J.E. Pineda, C. Quinn, C. Salji, S. Tisi, S. Walker-Smith, J. Di Francesco, M.R. Hogerheijde, D. Ward-Thompson, L.E. Allen, L.A. Cieza, M.M. Dunham, P.M. Harvey, K.R. Stapelfeldt, P. Bastien, H. Bunter, M. Chen, A. Chrysostomou, S. Coude, C.J. Davis, E. Drabek-Maunder, A. Duarte-Cabral, J. Greaves, J. Gregson, W. Holland, G. Joncas, J.M. Kirk, L.B.G. Knee, S. Mairs, K. Marsh, B.C. Matthews, G. Moriarty-Schieven, J. Rawlings, J. Richer, D. Robertson, E. Rosolowsky, S. Sadavoy, H. Thomas, N. Tothill, S. Viti, G.J. White, C.D. Wilson, J. Wouterloot, J. Yates, M. Zhu

Robert A. Gutermuth

We present SCUBA-2 450 and 850 μm observations of the Serpens MWC 297 region, part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey of nearby star-forming regions. Simulations suggest that radiative feedback influences the star formation process and we investigate observational evidence for this by constructing temperature maps. Maps are derived from the ratio of SCUBA-2 fluxes and a two-component model of the JCMT beam for a fixed dust opacity spectral index of β = 1.8. Within 40 arcsec of the B1.5Ve Herbig star MWC 297, the submillimetre fluxes are contaminated by free–free emission with a spectral index …

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A 24Μm Point Source Catalog Of The Galactic Plane From Spitzer/Mipsgal, R. A. Gutermuth, Mark Heyer

Robert A. Gutermuth

In this contribution, we describe the applied methods to construct a 24 μm based point source catalog derived from the image data of the MIPSGAL 24 μm Galactic Plane Survey and the corresponding data products. The high quality catalog product contains 933,818 sources, with a total of 1,353,228 in the full archive catalog. The source tables include positional and photometric information derived from the 24 μm images, source quality and confusion flags, and counterpart photometry from matched 2MASS, GLIMPSE, and WISE point sources. Completeness decay data cubes are constructed at 1' angular resolution that describe the varying background levels over …

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The Red Radio Ring: A Gravitationally Lensed Hyperluminous Infrared Radio Galaxy At Z=2.553 Discovered Through Citizen Science, J. E. Geach, A. More, A. Verma, P.J. Marshall, N. Jackson, P. E. Belles, R. Beswick, E. Baeten, M. Chavez, C. Cornen, B. E. Cox, T. Erben, N. J. Erickson, S. Garrington, P. A. Harrison, K. Harrington, D. H. Hughes, R. J. Ivison, C. Jordan, Y. T. Lin, A. Leauthaud, C. Lintott, S. Lynn, A. Kapadia, J. P. Kneib, C. Macmillan, M. Makler, G. Miller, A. Montana, R. Mujica, T. Muxlow, Gopal Narayanan, D. O Briain, T. O'Brien, M. Oguri, E. Paget, M. Parrish, N.P. Ross, E. Rozo, E. Rusu, E. S. Rykoff, D. Sanchez-Arguelles, R. Simpson, C. Snyder, F. P. Schloerb, M. Tecza, L. Van Waerbeke, J. Wilcox, M. Viero, G. W. Wilson, M. S. Yun, M. Zeballos

Gopal Narayanan

We report the discovery of a gravitationally lensed hyperluminous infrared galaxy (L_IR~10^13 L_sun) with strong radio emission (L_1.4GHz~10^25 W/Hz) at z=2.553. The source was identified in the citizen science project SpaceWarps through the visual inspection of tens of thousands of iJKs colour composite images of Luminous Red Galaxies (LRGs), groups and clusters of galaxies and quasars. Appearing as a partial Einstein ring (r_e~3") around an LRG at z=0.2, the galaxy is extremely bright in the sub-millimetre for a cosmological source, with the thermal dust emission approaching 1 Jy at peak. The redshift of the lensed galaxy is determined through the …

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The Herschel View Of The Dominant Mode Of Galaxy Growth From Z=4 To The Present Day, C. Schreiber, M. Pannella, D. Elbaz, M. Bethermin, H. Inami, M. Dickinson, B. Magnelli, T. Wang, H. Aussel, E. Daddi, S Juneau, X. Shu, M. T. Sargent, V. Buat, S.M. Faber, H.C. Ferguson, Mauro Giavalisco, A.M. Koekemoer, G. Magdis, G.E. Morrison, C. Papovich, P. Santini, D. Scott

Mauro Giavalisco

No abstract provided.

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Torque-Limited Growth Of Massive Black Holes In Galaxies Across Cosmic Tim, Daniel Angles-Alcazar, Feryal Ozel, Romeel Dave, Neal S. Katz, Juna Kollmeier, Benjamin D. Oppenheimer

Neal S. Katz

We combine cosmological hydrodynamic simulations with analytic models to evaluate the role of galaxy-scale gravitational torques on the evolution of massive black holes at the centers of star-forming galaxies. We confirm and extend our earlier results to show that torque-limited growth yields black holes and host galaxies evolving on average along the M BH-M bulge relation from early times down to z = 0 and that convergence onto the scaling relation occurs independent of the initial conditions and with no need for mass averaging through mergers or additional self-regulation processes. Smooth accretion dominates the long-term evolution, with black hole mergers …

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Csi 2264: Characterizing Young Stars In Ngc 2264 With Short-Duration, Periodic Flux Dips In Their Light Curves, John Stauffer, Ann Marie Cody, Pauline Mcginnis, Luisa Rebull, Lynne A. Hillenbrand, Neal. J. Turner, John Carpenter, Peter Plavchan, Sean Carey, Susan Terebey, Maria Morales-Calderon, Silvia H.P. Alencar, Jerome Bouvier, Laura Venuti, Lee Hartmann, Nuria Calvet, Giushi Micela, Ettore Flaccomio, Inseok Song, R. A. Gutermuth, David Barrado, Frederick J. Vrba, Kevin Covey, Debbie Padgett, William Herbst, Edward Gillen, Wladimir Lyra, Marcelo Medeiros Guimaraes, Herve Bouy, Fabio Favata

Robert A. Gutermuth

We identify nine young stellar objects (YSOs) in the NGC 2264 star-forming region with optical CoRoT light curves exhibiting short-duration, shallow periodic flux dips. All of these stars have infrared excesses that are consistent with their having inner disk walls near the Keplerian co-rotation radius. The repeating photometric dips have FWHMs generally less than 1 day, depths almost always less than 15%, and periods (3 < P < 11 days) consistent with dust near the Keplerian co-rotation period. The flux dips vary considerably in their depth from epoch to epoch, but usually persist for several weeks and, in two cases, were present in data collected in successive years. For several of these stars, we also measure the photospheric rotation period and find that the rotation and dip periods are the same, as predicted by standard "disk-locking" models. We attribute these flux dips to clumps of material in or near the inner disk wall, passing through our line of sight to the stellar photosphere. In some cases, these dips are also present in simultaneous Spitzer IRAC light curves at 3.6 and 4.5 microns. We characterize the properties of these dips, and compare the stars with light curves exhibiting this behavior to other classes of YSOs in NGC 2264. A number of physical mechanisms could locally increase the dust scale height near the inner disk wall, and we discuss several of those mechanisms; the most plausible mechanisms are either a disk warp due to interaction with the stellar magnetic field or dust entrained in funnel-flow accretion columns arising near the inner disk wall.

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Physical Sciences and Mathematics Commons^™

Full-Text Articles in Physical Sciences and Mathematics

Validation Of Argon From Underground Sources For Use In The Darkside-50 Detector, Thomas R. Alexander

Masters Theses

The Impact Of Terrestrial Noise On The Detectability And Reconstruction Of Gravitational Wave Signals From Core-Collapse Supernovae, Jessica Mciver

Doctoral Dissertations

An Empirical Approach To Understanding Of Star Formation In Dark Matter Halos, Zhankui Lu

Doctoral Dissertations

Gravitational Wave Astrophysics: Instrumentation, Detector Characterization, And A Search For Gravitational Signals From Gamma-Ray Bursts, Daniel Hoak

Doctoral Dissertations

Exact Solutions In Gravity: A Journey Through Spacetime With The Kerr-Schild Ansatz, Benjamin Ett

Doctoral Dissertations

Robert A. Gutermuth

A 24Μm Point Source Catalog Of The Galactic Plane From Spitzer/Mipsgal, R. A. Gutermuth, Mark Heyer

Robert A. Gutermuth

Gopal Narayanan

Mauro Giavalisco

Torque-Limited Growth Of Massive Black Holes In Galaxies Across Cosmic Tim, Daniel Angles-Alcazar, Feryal Ozel, Romeel Dave, Neal S. Katz, Juna Kollmeier, Benjamin D. Oppenheimer

Neal S. Katz

Robert A. Gutermuth