Cosmology, Relativity, and Gravity | Open Access Articles

On The Time Variation Of Dust Extinction And Gas Absorption For Type Ia Supernovae Observed Through A Nonuniform Interstellar Medium, Xiaosheng Huang, G Aldering, M. Biederman, B. Herger

Physics and Astronomy

For Type Ia supernovae (SNe Ia) observed through a nonuniform interstellar medium (ISM) in its host galaxy, we investigate whether the nonuniformity can cause observable time variations in dust extinction and in gas absorption due to the expansion of the SN photosphere with time. We show that, owing to the steep spectral index of the ISM density power spectrum, sizable density fluctuation amplitudes at the length scale of typical ISM structures () will translate to much smaller fluctuations on the scales of an SN photosphere. Therefore, the typical amplitude of time variation due to a nonuniform ISM, of absorption equivalent …

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A Gravitational-Wave Standard Siren Measurement Of The Hubble Constant, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, E. M. Gretarrson, B. Hughey, M. Muratore, J. W. W. Pratt, S. G. Schwalde, K. Staats, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

The detection of GW170817 (Abbott et al. 2017a) in both gravitational waves and electromagnetic waves heralds the age of gravitational-wave multi-messenger astronomy. On 17 August 2017 the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) (LIGO Scientific Collaboration et al. 2015) and Virgo (Acernese et al. 2015) detectors observed GW170817, a strong signal from the merger of a binary neutron-star system. Less than 2 seconds after the merger, a gamma-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO-Virgo-derived location of the gravitational-wave source (Abbott et al. 2017b; Goldstein et al. 2017; Savchenko et al. 2017). …

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Production Of Cosmological Observables During The Inflationary Epoch, Cody Goolsby-Cole

Doctoral Dissertations

This dissertation proposal explores the production of present day cosmological observables which might have been produced during the inflationary era. The first observable is the current net electric charge of our observable universe produced by charge fluctuations during inflation. Next, we examine the possibility of a signal in the primordial gravitational wave power spectrum produced by a scalar field with a time dependent mass. Finally, we examine primordial magnetic fields produced during inflation through the Ratra model coupling with the Schwinger effect.

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Full Band All-Sky Search For Periodic Gravitational Waves In The O1 Ligo Data, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, E. M. Gretarsson, B. Hughey, M. Muratore, J. W. W. Pratt, S. G. Schwalbe, K. Staats, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

We report on an all-sky search for periodic gravitational waves in the frequency band 20–475 Hz and with a frequency time derivative in the range of [−1.0,+0.1]×10−8 Hz/s. Such a signal could be produced by a nearby spinning and slightly nonaxisymmetric isolated neutron star in our galaxy. This search uses the data from Advanced LIGO’s first observational run, O1. No periodic gravitational wave signals were observed, and upper limits were placed on their strengths. The lowest upper limits on worst-case (linearly polarized) strain amplitude h0 are ∼4×10−25 near 170 Hz. For a circularly polarized source (most favorable orientation), the smallest …

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The Extinction Properties Of And Distance To The Highly Reddened Type Ia Supernova Sn 2012cu, Xiaosheng Huang, Z. Raha, G. Aldering, P. Antilogus, S. Bailey, C. Baltay, K. Barbary, D. Baugh, K. Boone, S. Bongard, C. Buton, J. Chen, N. Chotard, Y. Copin, P. Fagrelius, H. K. Fakhouri, U. Feindt, D. Fouchez, E. Gangler, B. Hayden, W. Hillebrandt, A. G. Kim, M. Kowalski, P. F. Leget, S. Lombardo, J. Nordin, R. Pain, E. Pecontal, R. Pereira, S. Perlmutter, D. Rabinowitz, M. Rigault, D. Rubin, K. Runge, C. Saunders, G. Smadja, C. Sofiatti, A. Stocker, N. Suzuki, S. Taubenberger, C. Tao, R. C. Thomas

Physics and Astronomy

Correcting Type Ia Supernova brightnesses for extinction by dust has proven to be a vexing problem. Here we study the dust foreground to the highly reddened SN 2012cu, which is projected onto a dust lane in the galaxy NGC 4772. The analysis is based on multi-epoch, spectrophotometric observations spanning from 3300–9200 Å, obtained by the Nearby Supernova Factory. Phase-matched comparison of the spectroscopically twinned SN 2012cu and SN 2011fe across 10 epochs results in the best-fit color excess of (, RMS) = (1.00, 0.03) and total-to-selective extinction ratio of (R V , RMS) = (2.95, 0.08) toward SN 2012cu …

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Testing Atomic Collision Theory With The Two-Photon Continuum Of Astrophysical Nebulae, Francisco Guzmán, N. R. Badnell, Marios Chatzikos, P. A. M. Van Hoof, R. J. R. Williams, Gary J. Ferland

Physics and Astronomy Faculty Publications

Accurate rates for energy-degenerate l-changing collisions are needed to determine cosmological abundances and recombination. There are now several competing theories for the treatment of this process, and it is not possible to test these experimentally. We show that the H i two-photon continuum produced by astrophysical nebulae is strongly affected by l-changing collisions. We perform an analysis of the different underlying atomic processes and simulate the recombination and two-photon spectrum of a nebula containing H and He. We provide an extended set of effective recombination coefficients and updated l-changing 2s − 2p transition rates using …

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Edgar Allan Poe’S Cosmology And Natural Theology: A Constructive Postmodern Appreciation, Theodore Walker

Perkins Faculty Research and Special Events

Contrary to some literary classifications, Edgar Allan Poe’s book-length prose poem Eureka is not intended to be fiction. In Eureka Poe was seriously attempting to advance ‘truth’ about the universe. Poe was doing natural science and poetry in the tradition of Samuel Taylor Coleridge and other natural philosophers. Poe’s prose poem is natural scientific astronomy and cosmology, plus natural theology, not science fiction.

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Cosmology, Relativity, and Gravity Commons^™

Full-Text Articles in Cosmology, Relativity, and Gravity

On The Time Variation Of Dust Extinction And Gas Absorption For Type Ia Supernovae Observed Through A Nonuniform Interstellar Medium, Xiaosheng Huang, G Aldering, M. Biederman, B. Herger

Physics and Astronomy

A Gravitational-Wave Standard Siren Measurement Of The Hubble Constant, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, E. M. Gretarrson, B. Hughey, M. Muratore, J. W. W. Pratt, S. G. Schwalde, K. Staats, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

Production Of Cosmological Observables During The Inflationary Epoch, Cody Goolsby-Cole

Doctoral Dissertations

Full Band All-Sky Search For Periodic Gravitational Waves In The O1 Ligo Data, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, E. M. Gretarsson, B. Hughey, M. Muratore, J. W. W. Pratt, S. G. Schwalbe, K. Staats, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

Physics and Astronomy

Testing Atomic Collision Theory With The Two-Photon Continuum Of Astrophysical Nebulae, Francisco Guzmán, N. R. Badnell, Marios Chatzikos, P. A. M. Van Hoof, R. J. R. Williams, Gary J. Ferland

Physics and Astronomy Faculty Publications

Edgar Allan Poe’S Cosmology And Natural Theology: A Constructive Postmodern Appreciation, Theodore Walker

Perkins Faculty Research and Special Events