Physical Sciences and Mathematics Commons^™

An Additional Pulsating Mode (7.35 Mhz) And Pulsations Timing Variations Of Pg 1613+426, Tomomi Otani, Terry D. Oswalt, Patrice Majewski, Riley Jordan, Marc Amaral, Adam Moss

Publications

We present the detection of an additional pulsation mode (7.35 mHz) of a subdwarf B star, PG 1613+426, and periodic Observed minus Calculated (O-C) variations for two existing pulsations. PG 1613+426 is near the hot end of the sdB instability strip. One pulsation mode (6.94 mHz) was detected so far by Bonanno et al. (2002) and another pulsation mode candidate (7.05 mHz) was proposed with a confidence level above 90% by Kuassivi and Ferlet (2005). To constrain sdB star evolutional scenarios, this star was monitored in 2010, 2011, 2015, and 2017 as a part of a project for finding companions …

Black Hole Hyperaccretion Inflow-Outflow Model. I. Long And Ultra-Long Gamma-Ray Bursts, Tong Liu, Cui-Ying Song, Bing Zhang, Wei-Min Gu, Alexander Heger

Physics & Astronomy Faculty Research

Long-duration gamma-ray bursts (LGRBs) and ultra-LGRBs (ULGRBs) originate from collapsars, in the center of which a newborn rotating stellar-mass black hole (BH) surrounded by a massive accretion disk may form. In the scenario of the BH hyperaccretion inflow-outflow model and Blandford-Znajek (BZ) mechanism to trigger gamma-ray bursts (GRBs), the real accretion rate to power a BZ jet is far lower than the mass supply rate from the progenitor star. The characteristics of the progenitor stars can be constrained by GRB luminosity observations, and the results exceed usual expectations. LGRBs lasting from several seconds to tens of seconds in the rest …

First Narrow-Band Search For Continuous Gravitational Waves From Known Pulsars In Advanced Detector 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

Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signal-to-noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars …

Gamma-Ray Metallic Magnetic Calorimeters With Nbta Passive Persistent Switches And Electroformed Au Absorbers, Ruslan Hummatov

Physics & Astronomy ETDs

Metallic Magnetic Calorimeters (MMCs) are low temperature particle detectors which can be used for a wide range of applications including high-resolution γ -ray spectroscopy. High energy resolution in γ -ray spectroscopy is desired for Non Destructive Assay (NDA) of nuclear material and improved measurements of nuclear data. Our group has been developing γ -ray MMCs that should ultimately provide energy resolution more than an order of magnitude better than the benchmark detector technology, high purity germanium detectors (HPGe). Two components of these MMCs have been developed as a part of this dissertation: an on-chip passive superconducting persistent current switch and …

The Architecture Of The Gw Ori Young Triple-Star System And Its Disk: Dynamical Masses, Mutual Inclinations, And Recurrent Eclipses, I. Czekala, S. M. Andrews, G. Torres, J. E. Rodriguez, Eric L.N. Jensen, K. G. Stassun, D. W. Latham, D. J. Wilner, M. A. Gully-Santiago, K. N. Grankin, M. B. Lund, R. B. Kuhn, D. J. Stevens, R. J. Siverd, D. James, B. S. Gaudi, B. J. Shappee, T. W.-S. Holoien

Physics & Astronomy Faculty Works

We present spatially and spectrally resolved Atacama Large Millimeter/submillimeter Array (ALMA) observations of gas and dust orbiting the pre-main-sequence hierarchical triple-star system GW Ori. A forward modeling of the ¹³CO and C¹⁸O J = 2–1 transitions permits a measurement of the total stellar mass in this system, 5.29 ± 0.09 M_⊙, and the circumtriple disk inclination, 137 fdg 6 ± 2 fdg 0. Optical spectra spanning a 35 yr period were used to derive new radial velocities and, coupled with a spectroscopic disentangling technique, revealed that the A and B components of GW Ori form a …

Pulsar J1411+2551: A Low-Mass Double Neutron Star System, J. G. Martinez, K. Stovall, P. C.C. Freire, J. S. Deneva, T. M. Tauris, A. Ridolfi, N. Wex, F. A. Jenet, M. A. Mclaughlin, M. Bagchi

Physics and Astronomy Faculty Publications and Presentations

In this work, we report the discovery and characterization of PSR J1411+2551, a new binary pulsar discovered in the Arecibo 327 MHz Drift Pulsar Survey. Our timing observations of the radio pulsar in the system span a period of about 2.5 years. This timing campaign allowed a precise measurement of its spin period (62.4 ms) and its derivative (9.6 ±0.7) ×10 -20 s s -1 ; from these, we derive a characteristic age of >9.1 Gyr and a surface magnetic field strength of <2.6 ×10 9 G. These numbers indicate that this pulsar was mildly recycled by accretion of matter from the progenitor of the companion star. The system has an eccentric (e =0.17) 2.61 day orbit. This eccentricity allows a highly significant measurement of the rate of advance of periastron, . Assuming general relativity accurately describes the orbital motion, this implies a total system mass M =2.538 ±0.022 M o . The minimum companion mass is 0.92 M o and the maximum pulsar mass is 1.62 M o . The large companion mass and the orbital eccentricity suggest that PSR J1411+2551 is a double neutron star system; the lightest known to date including the DNS merger GW170817. Furthermore, the relatively low orbital eccentricity and small proper motion limits suggest that the second supernova had a relatively small associated kick; this and the low system mass suggest that it was an ultra-stripped supernova.

Orbital Misalignment Of The Neptune-Mass Exoplanet Gj 436b With The Spin Of Its Cool Star, Vincent Bourrier, Christophe Lovis, Hervé Beust, David Ehrenreich, Gregory W. Henry, Nicola Astudillo-Defru, Romain Allart, Xavier Bonfils, Damien Ségransan, Xavier Delfosse, Heather M. Cegla, Aurélien Wyttenbach, Kevin Heng, Baptiste Lavie, Francesco Pepe

Information Systems and Engineering Management Research Publications

The angle between the spin of a star and the orbital planes of its planets traces the history of the planetary system. Exoplanets orbiting close to cool stars are expected to be on circular, aligned orbits because of strong tidal interactions with the stellar convective envelope. Spin–orbit alignment can be measured when the planet transits its star, but such ground-based spectroscopic measurements are challenging for cool, slowly rotating stars. Here we report the three-dimensional characterization of the trajectory of an exoplanet around an M dwarf star, derived by mapping the spectrum of the stellar photosphere along the chord transited by …

Gw170608: Observation Of A 19 Solar-Mass Binary Black Hole Coalescence, 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

On 2017 June 8 at 02:01:16.49 UTC, a gravitational-wave (GW) signal from the merger of two stellar-mass black holes was observed by the two Advanced Laser Interferometer Gravitational-Wave Observatory detectors with a network signal-to-noise ratio of 13. This system is the lightest black hole binary so far observed, with component masses of 12 +7 -2 M⨀ and 7 +2 -2 M⨀ (90% credible intervals). These lie in the range of measured black hole masses in low-mass X-ray binaries, thus allowing us to compare black holes detected through GWs with electromagnetic observations. The source’s luminosity distance is 340 +140 -140 Mpc, …

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 …

Unseen Science: Modern Discoveries Too Far Away Or Tiny For Human Eyes, Lucy Huang

Capstones

As science has progressed, scientists have realized that evidence goes beyond the realms of physical sight. Whether it is too small or difficult to find, scientists have developed different ways to get around this problem. We see this in cancer genomics and in extrasolar planetary research. Scientists use what they know and what they measure to validate their work.

https://lucy-huang-9tge.squarespace.com/

First Low-Frequency Einstein@Home All-Sky Search For Continuous Gravitational Waves In Advanced Ligo Data, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. Antier, S. Appert, K. Arai, M. C. Araya

Physics and Astronomy Faculty Publications and Presentations

We report results of a deep all-sky search for periodic gravitational waves from isolated neutron stars in data from the first Advanced LIGO observing run. This search investigates the low frequency range of Advanced LIGO data, between 20 and 100 Hz, much of which was not explored in initial LIGO. The search was made possible by the computing power provided by the volunteers of the Einstein@Home project. We find no significant signal candidate and set the most stringent upper limits to date on the amplitude of gravitational wave signals from the target population, corresponding to a sensitivity depth of 48.7 …

Relativistic Three-Dimensional Lippman-Schwinger Cross Sections For Space Radiation Applications, Charles M. Werneth, Xiaojing Xu, Ryan B. Norman, Khin M. Maung

Faculty Publications

Radiation transport codes require accurate nuclear cross sections to compute particle fluences inside shielding materials. The Tripathi semi-empirical reaction cross section, which includes over 60 parameters tuned to nucleon-nucleus (NA) and nucleus-nucleus (AA) data, has been used in many of the world’s best-known transport codes. Although this parameterization fits well to reaction cross section data, the predictive capability of any parameterization is questionable when it is used beyond the range of the data to which it was tuned. Using uncertainty analysis, it is shown that a relativistic three-dimensional Lippmann-Schwinger (LS3D) equation model based on Multiple Scattering Theory (MST) that uses …

First Narrow-Band Search For Continuous Gravitational Waves From Known Pulsars In Advanced Detector Data, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier, S. Appert

Physics and Astronomy Faculty Publications and Presentations

Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signal-to-noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars …

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 10^12.5 < M_halo < 10^14.5 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 …

Nonlinear Gravity Wave Forcing As A Source Of Acoustic Waves In The Mesosphere, Thermosphere, And Ionosphere, J. B. Snively

Publications

Numerical simulations demonstrate theoretical predictions that gravity waves with short periods (∼4–8 min) in the mesosphere and lower thermosphere may force secondary acoustic waves, with harmonic periods (∼2-4 minutes), that can reach detectable amplitudes in the thermosphere and ionosphere. The mechanism is through their vertical fluxes of vertical momentum, which lead to forcing as they are disrupted by varying stratification or instability. This is shown likely to occur where horizontally or radially opposing gravity waves interact at large amplitudes, such as above large convective sources, and after overturning. Evanescence and reflection of the waves can lead to further enhancements of …

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 (Σ_SFR), 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 …

Erratum: First Search For Gravitational Waves From Known Pulsars With Advanced Ligo (Astrophysical Journal (2017) 839 (12) Doi: 10.3847/1538-4357/Aa677f), B. P. Abbott, R. Abbott, T. D. Abbott, M. R. Abernathy, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, A. Allocca, P. A. Altin, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. Appert, K. Arai, M. C. Araya, J. S. Areeda, N. Arnaud, K. G. Arun, Tiffany Z. Summerscales

Faculty Publications

© 2017. The American Astronomical Society. All rights reserved. There is an error in Equation?(4) of the original paper, which should instead be (Formula Presented) This makes it consistent with Equation?(3) of Aasi et al. (2014), which was actually used when calculating the value of the Q22 upper limits from the h0 upper limits for the results of this paper.

First Low-Frequency Einstein@Home All-Sky Search For Continuous Gravitational Waves In Advanced Ligo Data, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, B. Hughey, J. W. W. Pratt, E. Schmidt, S. G. Schwalbe, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

We report results of a deep all-sky search for periodic gravitational waves from isolated neutron stars in data from the first Advanced LIGO observing run. This search investigates the low frequency range of Advanced LIGO data, between 20 and 100 Hz, much of which was not explored in initial LIGO. The search was made possible by the computing power provided by the volunteers of the Einstein@Home project. We find no significant signal candidate and set the most stringent upper limits to date on the amplitude of gravitational wave signals from the target population, corresponding to a sensitivity depth of 48.7 …

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 …

Search For Post-Merger Gravitational Waves From The Remnant Of The Binary Neutron Star Merger Gw170817, 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

The first observation of a binary neutron star (NS) coalescence by the Advanced LIGO and Advanced Virgo gravitational-wave (GW) detectors offers an unprecedented opportunity to study matter under the most extreme conditions. After such a merger, a compact remnant is left over whose nature depends primarily on the masses of the inspiraling objects and on the equation of state of nuclear matter. This could be either a black hole (BH) or an NS, with the latter being either long-lived or too massive for stability implying delayed collapse to a BH. Here, we present a search for GWs from the remnant …

Flow Anisotropy Due To Thread-Like Nanoparticle Agglomerations In Dilute Ferrofluids, Alexander Cali, Wah-Keat Lee, A. David Trubatch, Philip Yecko

Department of Applied Mathematics and Statistics Faculty Scholarship and Creative Works

Improved knowledge of the magnetic field dependent flow properties of nanoparticle-based magnetic fluids is critical to the design of biomedical applications, including drug delivery and cell sorting. To probe the rheology of ferrofluid on a sub-millimeter scale, we examine the paths of 550 μm diameter glass spheres falling due to gravity in dilute ferrofluid, imposing a uniform magnetic field at an angle with respect to the vertical. Visualization of the spheres’ trajectories is achieved using high resolution X-ray phase-contrast imaging, allowing measurement of a terminal velocity while simultaneously revealing the formation of an array of long thread-like accumulations of magnetic …

Exterior Giant Planet Effects On Terrestrial Architecture, Anna Corinne Childs

UNLV Theses, Dissertations, Professional Papers, and Capstones

Terrestrial planet formation is a chaotic and violent process which is not fully understood. Prior to Kepler, Solar System observations were the basis for planet formation models. How- ever, Kepler observations have shown that exoplanet systems are very different from our solar system, thus requiring a more complete planet formation model. With advancements in com- putational ability, N-body integrators, and collision models, we can explore planet formation by experimenting with simulations in different parameter space. Our Solar System has shown us that exterior giant planets can play a vital role in the shaping of the final terrestrial planet system. Our …

Probing Broad Line Regions Of Active Galactic Nuclei, Champika Sandamali Weerasooriya

UNLV Theses, Dissertations, Professional Papers, and Capstones

The broad line regions (BLR) of Type I Active galactic nuclei (AGN) are too small to be spatially resolved even with the most powerful telescopes available. Observations suggest that BLR gas is moving under the influence of the gravitational potential of the central supermassive black-hole (SMBH) and responds to the variations in the ionizing continuum flux of the accretion disk, giving rise to broad emission line variations with a time delay. Reverberation mapping campaigns seek to use this time variability to resolve the BLRs in the time domain instead of spatial domain, providing a way to infer geometry and kinematics …

Facing The Sun, Frank Prendergast, Muiris O'Sullivan, Ken Williams, Gabriel Cooney

Articles

December 2017 marked 50 years since archaeologist Michael J. O’Kelly first observed the solar illumination of the burial chamber in the Neolithic passage tomb at Newgrange during the period of the winter solstice. O’Kelly subsequently recorded direct sunlight entering Newgrange through the ‘especially contrived slit which lies under the roof-box at the outer end of the passage roof’ on 21 December 1969. The discovery of this historic phenomenon, dating back over 5,000 years, captured the public interest and imagination at that time and ever since. In this major article published in the Winter 2017 edition of Archaeology Ireland (date of …

Deep Subaru Hyper Suprime-Cam Observations Of Milky Way Satellites Columba I And Triangulum Ii*, Jeffrey Carlin, David Sand, Ricardo Muñoz, Kristine Spekkens, Beth Willman, Denija Crnojević, Duncan Forbes, Jonathan Hargis, Evan Kirby, Annika Peter, Aaron Romanowsky, Jay Strader

Faculty Publications

We present deep, wide-field Subaru Hyper Suprime-Cam photometry of two recently discovered satellites of the Milky Way (MW): Columba I (Col I) and Triangulum II (Tri II). The color–magnitude diagrams of both objects point to exclusively old and metal-poor stellar populations. We re-derive structural parameters and luminosities of these satellites, and find for Col I and for Tri II, with corresponding half-light radii of pc and pc. The properties of both systems are consistent with observed scaling relations for MW dwarf galaxies. Based on archival data, we derive upper limits on the neutral gas content of these dwarfs, and find …

Probing The Black-Hole-Mass-Galaxy Connection Of Active Galaxies Using 2d Galaxy Fitting Techniques On Near-Infrared Images, Isak Dan Stomberg

Physics

Active Galactic Nuclei (AGNs) provide a unique opportunity to measure the mass of supermassive black holes located in the centers of their host galaxies. This enables studying the scaling relations between the mass of the black hole and the properties of the host galaxy.

In this thesis, we present an investigation of the relationship between black hole masses and the host galaxy bulge and total luminosity for a pilot sample of 15 objects imaged in the near-infrared with the 8m telescope of Gemini North observatory. We perform a 2D decomposition of the host galaxies using the software Galfit and obtain …

Search For High-Energy Neutrinos From Binary Neutron Star Merger Gw170817 With Antares, Icecube, And The Pierre Auger Observatory, M. G. Aartsen, 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

The Advanced LIGO and Advanced Virgo observatories recently discovered gravitational waves from a binary neutron star inspiral. A short gamma-ray burst (GRB) that followed the merger of this binary was also recorded by the Fermi Gamma-ray Burst Monitor (Fermi-GBM), and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), indicating particle acceleration by the source. The precise location of the event was determined by optical detections of emission following the merger. We searched for high-energy neutrinos from the merger in the GeV–EeV energy range using the ANTARES, IceCube, and Pierre Auger Observatories. No neutrinos directionally coincident …

Estimating The Contribution Of Dynamical Ejecta In The Kilonova Associated With Gw170817, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier

Physics and Astronomy Faculty Publications and Presentations

The source of the gravitational-wave (GW) signal GW170817, very likely a binary neutron star merger, was also observed electromagnetically, providing the first multi-messenger observations of this type. The two-week-long electromagnetic (EM) counterpart had a signature indicative of an r-process-induced optical transient known as a kilonova. This Letter examines how the mass of the dynamical ejecta can be estimated without a direct electromagnetic observation of the kilonova, using GW measurements and a phenomenological model calibrated to numerical simulations of mergers with dynamical ejecta. Specifically, we apply the model to the binary masses inferred from the GW measurements, and use the resulting …

Detection Of Survival And Proliferation Of Sulfate Reducers Under Simulated Martian Atmospheric And Soil Conditions, Sergio Mosquera Mora

Graduate Theses and Dissertations

Numerous studies have tried to determine the survivability and proliferation of microorganisms under simulated Martian conditions. Furthermore, most of them have been focused on the ability of these microbes to cope with high brines’ salt (NaCl) concentrations inherent of the Martian surface. However, there are not studies related to the ability of bacteria to survive on subsurface environments that have increasing concentrations of sulfate compounds. For this research, a group of microorganisms known as sulfate-reducing bacteria or simply sulfate reducers were chosen due to their ability to use sulfate compounds as terminal electron acceptors to produce metabolic energy, their tolerance …

On The Progenitor Of Binary Neutron Star Merger Gw170817, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier

Physics and Astronomy Faculty Publications and Presentations

On 2017 August 17 the merger of two compact objects with masses consistent with two neutron stars was discovered through gravitational-wave (GW170817), gamma-ray (GRB 170817A), and optical (SSS17a/AT 2017gfo) observations. The optical source was associated with the early-type galaxy NGC 4993 at a distance of just ∼40 Mpc, consistent with the gravitational-wave measurement, and the merger was localized to be at a projected distance of ∼2 kpc away from the galaxy's center. We use this minimal set of facts and the mass posteriors of the two neutron stars to derive the first constraints on the progenitor of GW170817 at the …