Confirmation Of The Nature Of The Absorber In Iras 09104+4109,
2013
Institute of Astronomy, University of Cambridge
Confirmation Of The Nature Of The Absorber In Iras 09104+4109, Chia-Ying Chiang, E. M. Cackett, P. Gandhi, A. C. Fabian
Physics and Astronomy Faculty Research Publications
We present the first long Suzaku observation of the hyperluminous infrared galaxy IRAS 09104+4109 which is dominated by a Type 2 AGN. The infrared to X-ray spectral energy distribution (SED) indicates that the source is an obscured quasar with a Compton-thin absorber. However, the 3σ hard X-ray detection of the source with the BeppoSAX PDS suggested a reflection-dominated, Compton-thick view. The high-energy detection was later found to be possibly contaminated by another Type 2 AGN, NGC 2785, which is only 17 arcmin away. Our new Suzaku observation offers simultaneous soft and hard X-ray coverage and excludes contamination from NGC 2785. …
Revealing The X-Ray Source In Iras 13224-3809 Through Flux-Dependent Reverberation Lags,
2013
Institute of Astronomy, Cambridge
Revealing The X-Ray Source In Iras 13224-3809 Through Flux-Dependent Reverberation Lags, E. Kara, A. C. Fabian, E. M. Cackett, G. Miniutti, P. Uttley
Physics and Astronomy Faculty Research Publications
IRAS 13224-3809 was observed in 2011 for 500 ks with the XMM-Newton observatory. We detect highly significant X-ray lags between soft (0.3-1 keV) and hard (1.2-5 keV) energies. The hard band lags the soft at low frequencies (i.e. hard lag), while the opposite (i.e. soft lag) is observed at high frequencies. In this paper, we study the lag during flaring and quiescent periods. We find that the frequency and absolute amplitude of the soft lag are different during high-flux and low-flux periods. During the low-flux intervals, the soft lag is detected at higher frequencies and with smaller amplitude. Assuming that …
Discovery Of Fe Kα X-Ray Reverberation Around The Black Holes In Mcg-5-23-16 And Ngc 7314,
2013
University of Maryland
Discovery Of Fe Kα X-Ray Reverberation Around The Black Holes In Mcg-5-23-16 And Ngc 7314, A. Zoghbi, C. Reynolds, E. M. Cackett, G. Miniutti, E. Kara, A. C. Fabian
Physics and Astronomy Faculty Research Publications
Several X-ray observations have recently revealed the presence of reverberation time delays between spectral components in active galactic nuclei. Most of the observed lags are between the power-law Comptonization component, seen directly, and the soft excess produced by reflection in the vicinity of the black hole. NGC 4151 was the first object to show these lags in the iron K band. Here, we report the discovery of reverberation lags in the Fe K band in two other sources: MCG-5-23-16 and NGC 7314. In both objects, the 6-7 keV band, where the Fe Kα line peaks, lags the bands at lower …
Application Of The No-Core Symplectic Shell Model To Beryllium And Carbon Isotopes,
2013
Louisiana State University
Application Of The No-Core Symplectic Shell Model To Beryllium And Carbon Isotopes, Mia Cherise Ferriss
Honors Capstones
No abstract provided.
Phys 491/891,
2013
University of Nebraska - Lincoln
Using The Radial Velocity To Search For Orbiting Planets Around Mira,
2013
University of Minnesota - Morris
Using The Radial Velocity To Search For Orbiting Planets Around Mira, Emma Molden
Undergraduate Research Symposium 2013
We researched radio astronomical data from the star Omicron Ceti, more commonly known as Mira, to determine if there is evidence for orbiting planets. There is a variation in the silicon monoxide maser radial velocity of Mira that could have been due to the effect of orbiting planets. We analyzed the radial velocity data collected from Mira over the past forty years. The data were examined for periodicities. A periodicity refers to a repeating pattern within the data. Three possible frequencies were found. Each frequency within the star had the potential to be a pattern caused by an orbiting planet. …
The Nature Of The H2-Emitting Gas In The Crab Nebula,
2013
Michigan State University
The Nature Of The H2-Emitting Gas In The Crab Nebula, C. T. Richardson, J. A. Baldwin, Gary J. Ferland, E. D. Loh, C. A. Kuehn, A. C. Fabian, Philippe Salomé
Physics and Astronomy Faculty Publications
Understanding how molecules and dust might have formed within a rapidly expanding young supernova remnant is important because of the obvious application to vigorous supernova activity at very high redshift. In previous papers, we have mapped the Crab nebula (the Crab) in a rotovibrational H2emission line, and then measured the molecular excitation temperature for a few of the brighter H2-emitting knots that we have found to be scattered throughout the Crab's filaments. We found that H2 emission is often quite strong, correlates with optical low-ionization emission lines and has a surprisingly high excitation temperature. Here, …
Stories Of The Stars: The History And Folklore Of Tibetan Ethnoastronomy,
2013
SIT Study Abroad
Stories Of The Stars: The History And Folklore Of Tibetan Ethnoastronomy, Mara Johnson-Groh
Independent Study Project (ISP) Collection
Traditionally, the night sky played an important role in the lives of Tibetans. Stars and constellations were used in navigation and in telling time. Folklore and proverbs surround these constellations and there are myths about the moon and planets as well. However, many of the stories that can be found today either originate in or are influenced by Indian culture. With the introduction of Buddhism to Tibet, came Vedic texts on astrology, which had a profound impact on the culture of ethnoastronomy in the region. Adapted Vedic astrology, merged with practices from China, eventually replaced traditional ethnoastronomy. Because of the …
A Statistical Analysis Of Electromagnetic Ion Cyclotron (Emic) Waves And Their Correlation To The 11-Year Solar Cycle,
2013
University of New Hampshire - Main Campus
A Statistical Analysis Of Electromagnetic Ion Cyclotron (Emic) Waves And Their Correlation To The 11-Year Solar Cycle, Erik A. Lindgren
Honors Theses and Capstones
This thesis presents a statistical analysis of EMIC waves measured at Halley Research Station from 2008 through 2012. An introduction covering the origin of and theory behind EMIC waves is provided, along with a background covering previous statistical research regarding EMIC waves. Guidelines regarding EMIC wave definition and analysis are described along with examples of how they were used. The data shows an increase in the total number of EMIC waves as well as the number and percentage of EMIC waves with maximum frequency above 1 Hz during the 5-year period. The results suggest that the total number of EMIC …
Transport Of Solar Energetic Particles Accelerated By Icme Shocks: Reproducing The Reservoir Phenomenon,
2013
Chinese Academy of Sciences
Transport Of Solar Energetic Particles Accelerated By Icme Shocks: Reproducing The Reservoir Phenomenon, Gang Qin, Y Wang, Ming Zhang, Silvia Dalla
Aerospace, Physics, and Space Science Faculty Publications
In this work, gradual solar energetic particle (SEP) events observed by multiple spacecraft are investigated with model simulations. Based on a numerical solution of the Fokker-Planck focused transport equation including perpendicular diffusion of particles, we obtained the fluxes of SEPs accelerated by an interplanetary coronal mass ejection driven shock as it propagates outward through the three-dimensional Parker interplanetary magnetic field. The shock is treated as a moving source of energetic particles with an assumed particle distribution function. We look at the time profiles of particle flux as they are observed simultaneously by multiple spacecraft located at different locations. The dependence …
The Thermodynamics Of Dna Loop Formation, From J To Z,
2013
The University of Texas Rio Grande Valley
The Thermodynamics Of Dna Loop Formation, From J To Z, Stephen D. Levene, Stefan M. Giovan, Andreas Hanke, Massa J. Shoura
Physics & Astronomy Faculty Publications
The formation of DNA loops is a ubiquitous theme in biological processes, including DNA replication, recombination and repair, and gene regulation. These loops are mediated by proteins bound at specific sites along the contour of a single DNA molecule, in some cases many thousands of base pairs apart. Loop formation incurs a thermodynamic cost that is a sensitive function of the length of looped DNA as well as the geometry and elastic properties of the DNA-bound protein. The free energy of DNA looping is logarithmically related to a generalization of the Jacobson-Stockmayer factor for DNA cyclization, termed the J factor. …
Testing Galaxy Formation Models With The Ghosts Survey : The Color Profile Of M81'S Stellar Halo.,
2013
University of Michigan-Ann Arbor
Testing Galaxy Formation Models With The Ghosts Survey : The Color Profile Of M81'S Stellar Halo., Antonela Monachesi, Eric F. Bell, David J. Radburn-Smith, Marija Vlajic, Roelof S. De Jong, Jeremy Bailin, Julianne J. Dalcanton, Benne W. Holwerda, David Streich
Faculty and Staff Scholarship
We study the properties of the stellar populations in M81’s outermost part, which hereafter we will call the stellar halo, using Hubble Space Telescope (HST) Advanced Camera for Surveys observations of 19 fields from the GHOSTS survey. The observed fields probe the stellar halo out to a projected distance of ∼50 kpc from the galactic center. Each field was observed in both F606W and F814W filters. The 50% completeness levels of the color–magnitude diagrams (CMDs) are typically at 2 mag below the tip of the red giant branch (TRGB). Fields at distances closer than 15 kpc show evidence of disk-dominated …
Rainich-Type Conditions For Null Electrovacuum Spacetimes I,
2013
Department of Physics, Utah State University
Rainich-Type Conditions For Null Electrovacuum Spacetimes I, Charles G. Torre
Research Vignettes
In this worksheet I describe local Rainich-type conditions on a spacetime geometry which are necessary and sufficient for the existence of a solution of the Einstein-Maxwell equations with a null electromagnetic field. When it exists, the electromagnetic field is easily constructed.
Determination Of Average Loss Lifetimes For Near‐Earth Electrons In Solar Storms,
2013
Washington University in St Louis
Determination Of Average Loss Lifetimes For Near‐Earth Electrons In Solar Storms, John Blears
Undergraduate Theses—Unrestricted
The rate of electron wave‐particle scattering in the near‐Earth magnetosphere is investigated using multiple simulations of solar storms from solar cycle 23 (1996‐2005). Simulations are created using the Hot Electron and Ion Drift Integrator (HEIDI) model, which analyzes the drifts of keV‐energy electrons through the inner magnetosphere and identifies the precipitation of these particles into the upper atmosphere. The loss lifetime formulation used by HEIDI, which represents the rate at which the keV‐energy of the electrons is extinguished, predicts unreasonably large loss lifetimes deep in the inner magnetosphere. This discrepancy between the values used by the HEIDI model and those …
Multi-Wavelength Observations Of Supernova 2011ei: Time-Dependent Classification Of Type Iib And Ib Supernovae And Implications For Their Progenitors,
2013
Harvard-Smithsonian Center for Astrophysics
Multi-Wavelength Observations Of Supernova 2011ei: Time-Dependent Classification Of Type Iib And Ib Supernovae And Implications For Their Progenitors, Dan Milisavljevic, Raffaella Margutti, Alicia M. Soderberg, Giuliano Pignata, Laura Chomiuk, Robert A. Fesen
Dartmouth Scholarship
We present X-ray, UV/optical, and radio observations of the stripped-envelope, core-collapse supernova (SN) 2011ei, one of the least luminous SNe IIb or Ib observed to date. Our observations begin with a discovery within 1 day of explosion and span several months afterward. Early optical spectra exhibit broad, Type II-like hydrogen Balmer profiles that subside rapidly and are replaced by Type Ib-like He-rich features on the timescale of one week. High-cadence monitoring of this transition suggests that absorption attributable to a high velocity (> 12,000 km/s) H-rich shell is not rare in Type Ib events. Radio observations imply a shock velocity …
Experimental Analysis Of Energy-Based Acoustic Arrays For Measurement Of Rocket Noise Fields,
2013
Brigham Young University - Provo
Experimental Analysis Of Energy-Based Acoustic Arrays For Measurement Of Rocket Noise Fields, Jarom Henry Giraud
Theses and Dissertations
Microphone arrays are useful for measuring acoustic energy quantities (e.g. acoustic intensity) in the near-field of a full-scale solid rocket motor. Proper characterization of a rocket plume as a noise source will allow for more accurate predictions in engineering models that design for protection of structures, payloads and personnel near the rockets. Acoustic intensity and energy density quantities were measured in three rocket noise fields and have shown that the apparent source region of the rocket becomes smaller and moves upstream as frequency increases. Theoretical results accounting for some scattering and finite-difference errors arising in these types of energy-based measurements …
Brief History Of Curvature,
2013
Dartmouth College
Brief History Of Curvature, Robert R. Caldwell, Steven S. Gubser
Dartmouth Scholarship
The trace of the stress-energy tensor of the cosmological fluid, proportional to the Ricci scalar curvature in general relativity, is determined on cosmic scales for times ranging from the inflationary epoch to the present day in the expanding Universe. The post-inflationary epoch and the thermal history of the relativistic fluid, in particular the QCD transition from asymptotic freedom to confinement and the electroweak phase transition, leave significant imprints on the scalar curvature. These imprints can be of either sign and are orders of magnitude larger than the values that would be obtained by naively extrapolating the pressureless matter of the …
Superfluidity In Neutron Stars,
2013
Washington University in St Louis
Superfluidity In Neutron Stars, Samuel J. Witte
Undergraduate Theses—Unrestricted
Nucleon pairing is studied with specific considerations directed toward the possible influence on neutron star cooling. We present an in-depth analysis of BCS theory using realistic nuclear potentials and consider the impact short-range correlations can have on the gap. Gap calculations are incorporated into neutron star cooling simulations and the significance of the 3P2 −3F2 channel in various hadronic cooling models is closely examined. An analysis of the 1S0 gap in neutron matter suggests short-range correlations can drastically alter the magnitude, density range, and temperature dependence of the gap. While the newly constructed 1S0 gap does not significantly alter the …
Impact And Signatures Of Deglaciation On The Cryosphere, Landscape, And Habitability Of Earth And Mars,
2013
SETI Institute/CSC and NASA Ames Research Center
Impact And Signatures Of Deglaciation On The Cryosphere, Landscape, And Habitability Of Earth And Mars, Nathalie A. Cabrol, Andrew G. Fountain, J. S. Kargel
Geology Faculty Publications and Presentations
Science questions can help bridge Astrobiology and Earth Science disciples around the theme of planetary deglaciation.
An X-Rays Survey Of The Young Stellar Population Of The Lynds 1641 And Iota Orionis Regions,
2013
Harvard University
An X-Rays Survey Of The Young Stellar Population Of The Lynds 1641 And Iota Orionis Regions, I. Pillitteri, S. J. Wolk, S. T. Megeath, L. Allen, J. Bally, Marc Gagné, R. A. Gutermuth, L. Hartman, G. Micela, P. Myers, J. M. Oliveira, S. Sciortino, F. Walter, L. Rebull, J. Stauffer
Earth & Space Sciences Faculty Publications
We present an XMM-Newton survey of the part of Orion A cloud south of the Orion Nebula. This survey includes the Lynds 1641 (L1641) dark cloud, a region of the Orion A cloud with very few massive stars and hence a relatively low ambient UV flux, and the region around the O9 III star Orionis. In addition to proprietary data, we used archival XMM data of the Orion Nebula Cluster (ONC) to extend our analysis to a major fraction of the Orion A cloud. We have detected 1060 X-ray sources in L1641 and Ori region. About 94% of the sources …
