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2013

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Articles 31 - 60 of 371

Full-Text Articles in Astrophysics and Astronomy

Multiperiodicity, Modulations And Flip-Flops In Variable Star Light Curves Ii. Analysis Of Ii Pegasus Photometry During 1979–2010, Marjaana Lindborg, Maarit J. Mantere, Nigul Olspert, Jaan Pelt, Thomas Hackman, Gregory W. Henry, Lauri Jetsu, Klaus G. Strassmeier Nov 2013

Multiperiodicity, Modulations And Flip-Flops In Variable Star Light Curves Ii. Analysis Of Ii Pegasus Photometry During 1979–2010, Marjaana Lindborg, Maarit J. Mantere, Nigul Olspert, Jaan Pelt, Thomas Hackman, Gregory W. Henry, Lauri Jetsu, Klaus G. Strassmeier

Information Systems and Engineering Management Research Publications

Aims. According to previously published Doppler images of the magnetically active primary giant component of the RS CVn binary II Peg, the surface of the star was dominated by one single active longitude that was clearly drifting in the rotational frame of the binary system during 1994-2002; later imaging for 2004–2010, however, showed decreased and chaotic spot activity, with no signs of the drift pattern. Here we set out to investigate from a more extensive photometric dataset whether this drift is a persistent phenomenon, in which case it could be caused either by an azimuthal dynamo wave or be an …

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Non-Potential Fields In The Quiet Sun Network: Extreme-Ultraviolet And Magnetic Footpoint Observations, David L. Chesney, Hakeem M. Oluseyi, Norton B. Orange Nov 2013

Non-Potential Fields In The Quiet Sun Network: Extreme-Ultraviolet And Magnetic Footpoint Observations, David L. Chesney, Hakeem M. Oluseyi, Norton B. Orange

Aerospace, Physics, and Space Science Faculty Publications

The quiet Sun (QS) magnetic network is known to contain dynamics which are indicative of non-potential fields. Non-potential magnetic fields forming “S-shaped” loop arcades can lead to the breakdown of static activity and have only been observed in high temperature X-ray coronal structures—some of which show eruptive behavior. Thus, analysis of this type of atmospheric structuring has been restricted to large-scale coronal fields. Here we provide the first identification of non-potential loop arcades exclusive to the QS supergranulation network. High-resolution Atmospheric Imaging Assembly data from the Solar Dynamics Observatory have allowed for the first observations of fine-scale “S-shaped” loop arcades …

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Directed Search For Continuous Gravitational Waves From The Galactic Center, J. Aasi, Daniel Bessis, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano, Robert Stone, Lappoon R. Tang, Cristina V. Torres Nov 2013

Directed Search For Continuous Gravitational Waves From The Galactic Center, J. Aasi, Daniel Bessis, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano, Robert Stone, Lappoon R. Tang, Cristina V. Torres

Physics & Astronomy Faculty Publications

We present the results of a directed search for continuous gravitational waves from unknown, isolated neutron stars in the Galactic center region, performed on two years of data from LIGO’s fifth science run from two LIGO detectors. The search uses a semicoherent approach, analyzing coherently 630 segments, each spanning 11.5 hours, and then incoherently combining the results of the single segments. It covers gravitational wave frequencies in a range from 78 to 496 Hz and a frequency-dependent range of first-order spindown values down to −7.86×10−8  Hz/s at the highest frequency. No gravitational waves were detected. The 90% confidence upper limits …

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Mapping Of The Quasi-Periodic Oscillations At The Flank Magnetopause Into The Ionosphere, E. R. Dougal, K. Nykyri, T. W. Moore Nov 2013

Mapping Of The Quasi-Periodic Oscillations At The Flank Magnetopause Into The Ionosphere, E. R. Dougal, K. Nykyri, T. W. Moore

Publications

We have estimated the ionospheric location, area, and travel time of quasi-periodic oscillations originating from the magnetospheric flanks. This was accomplished by utilizing global and local MHD models and Tsyganenko semi-empirical magnetic field model on multiple published and four new cases believed to be caused by the Kelvin– Helmholtz Instability. Finally, we used auroral, magnetometer, and radar instruments to observe the ionospheric signatures. The ionospheric magnetic latitude determined using global MHD and Tsyganenko models ranged from 58.3–80.2 degrees in the Northern Hemisphere and −59.6 degrees to −83.4 degrees in the Southern Hemisphere. The ionospheric magnetic local time ranged between 5.0–13.8 …

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Freezing Out Early Dark Energy, Jannis Bielefeld, W. L. Kimmy Wu, Robert R. Caldwell, Olivier Doré Nov 2013

Freezing Out Early Dark Energy, Jannis Bielefeld, W. L. Kimmy Wu, Robert R. Caldwell, Olivier Doré

Dartmouth Scholarship

A phenomenological model of dark energy that tracks the baryonic and cold dark matter at early times but resembles a cosmological constant at late times is explored. In the transition between these two regimes, the dark energy density drops rapidly as if it were a relic species that freezes out, during which time the equation of state peaks at +1. Such an adjustment in the dark energy density, as it shifts from scaling to potential domination, could be the signature of a trigger mechanism that helps explain the late-time cosmic acceleration. We show that the non-negligible dark energy density at …

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The Xmm-Newton Spectrum Of A Candidate Recoiling Supermassive Black Hole: An Elusive Inverted P-Cygni Profile, G. Lanzuisi, F. Civano, S. Marchesi, A. Comastri Nov 2013

The Xmm-Newton Spectrum Of A Candidate Recoiling Supermassive Black Hole: An Elusive Inverted P-Cygni Profile, G. Lanzuisi, F. Civano, S. Marchesi, A. Comastri

Dartmouth Scholarship

We present a detailed spectral analysis of new XMM-Newton data of the source CXOC J100043.1+020637, also known as CID-42, detected in the COSMOS survey at z = 0.359. Previous works suggested that CID-42 is a candidate recoiling supermassive black hole (SMBH) showing also an inverted P-Cygni profile in the X-ray spectra at ~6 keV (rest) with an iron emission line plus a redshifted absorption line (detected at 3σ in previous XMM-Newton and Chandra observations). Detailed analysis of the absorption line suggested the presence of ionized material flowing into the black hole at high velocity. In the …

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Spectral Distortion In A Radially Inhomogeneous Cosmology, R. R. Caldwell, N. A. Maksimova Nov 2013

Spectral Distortion In A Radially Inhomogeneous Cosmology, R. R. Caldwell, N. A. Maksimova

Dartmouth Scholarship

The spectral distortion of the cosmic microwave background blackbody spectrum in a radially inhomogeneous space-time, designed to exactly reproduce a ΛCDM expansion history along the past light cone, is shown to exceed the upper bound established by COBE-FIRAS by a factor of approximately 3700. This simple observational test helps uncover a slew of pathological features that lie hidden inside the past light cone, including a radially contracting phase at decoupling and, if followed to its logical extreme, a naked singularity at the radially inhomogeneous big bang.

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The Stochastic Background: Scaling Laws And Time To Detection For Pulsar Timing Arrays, X. Siemens, Justin A. Ellis, Fredrick A. Jenet, Joseph D. Romano Nov 2013

The Stochastic Background: Scaling Laws And Time To Detection For Pulsar Timing Arrays, X. Siemens, Justin A. Ellis, Fredrick A. Jenet, Joseph D. Romano

Physics & Astronomy Faculty Publications

We derive scaling laws for the signal-to-noise ratio of the optimal cross-correlation statistic, and show that the large power-law increase of the signal-to-noise ratio as a function of the observation time T that is usually assumed holds only at early times. After enough time has elapsed, pulsar timing arrays enter a new regime where the signal to noise only scales as . In addition, in this regime the quality of the pulsar timing data and the cadence become relatively unimportant. This occurs because the lowest frequencies of the pulsar timing residuals become gravitational-wave dominated. Pulsar timing arrays enter this regime …

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Searching For Millisecond Pulsars: Surveys, Techniques And Prospects, Kevin Stovall, Duncan R. Lorimer, R. S. Lynch Nov 2013

Searching For Millisecond Pulsars: Surveys, Techniques And Prospects, Kevin Stovall, Duncan R. Lorimer, R. S. Lynch

Physics & Astronomy Faculty Publications

Searches for millisecond pulsars (which we here loosely define as those with periods < 20 ms) in the galactic field have undergone a renaissance in the past five years. New or recently refurbished radio telescopes utilizing cooled receivers and state-of-the art digital data acquisition systems are carrying out surveys of the entire sky at a variety of radio frequencies. Targeted searches for millisecond pulsars in point sources identified by the Fermi Gamma-ray Space Telescope have proved phenomenally successful, with over 50 discoveries in the past five years. The current sample of millisecond pulsars now numbers almost 200 and, for the first time in 25 years, now outnumbers their counterparts in galactic globular clusters. While many of these searches are motivated to find pulsars which form part of pulsar timing arrays, a wide variety of interesting systems are now being found. Following a brief overview of the millisecond pulsar phenomenon, we describe these searches and present some of …

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Hard X-Ray Lags In Active Galactic Nuclei: Testing The Distant Reverberation Hypothesis With Ngc 6814, D. J. Walton, A. Zoghbi, E. M. Cackett, P. Uttley, F. A. Harrison, A. C. Fabian, E. Kara, J. M. Miller, R. C. Reis, C. S. Reynolds Nov 2013

Hard X-Ray Lags In Active Galactic Nuclei: Testing The Distant Reverberation Hypothesis With Ngc 6814, D. J. Walton, A. Zoghbi, E. M. Cackett, P. Uttley, F. A. Harrison, A. C. Fabian, E. Kara, J. M. Miller, R. C. Reis, C. S. Reynolds

Physics and Astronomy Faculty Research Publications

We present an X-ray spectral and temporal analysis of the variable active galaxy NGC 6814, observed with Suzaku during 2011 November. Remarkably, the X-ray spectrum shows no evidence for the soft excess commonly observed amongst other active galaxies, despite its relatively low level of obscuration, and is dominated across the whole Suzaku bandpass by the intrinsic powerlaw-like continuum. Despite this, we clearly detect the presence of a low-frequency hard lag of ~1600 s between the 0.5-2.0 and 2.0-5.0 keV energy bands at greater than 6σ significance, similar to those reported in the literature for a variety of other active galactic …

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High-Resolution Near-Infrared Spectroscopy Of Hd 100546. Ii. Analysis Of Variable Rovibrational Co Emission Lines, Sean D. Brittain, Joan Najita, John S. Carr, Joseph Liskowsky, Matthew R. Troutman, Greg W. Doppmann Nov 2013

High-Resolution Near-Infrared Spectroscopy Of Hd 100546. Ii. Analysis Of Variable Rovibrational Co Emission Lines, Sean D. Brittain, Joan Najita, John S. Carr, Joseph Liskowsky, Matthew R. Troutman, Greg W. Doppmann

Publications

We present observations of rovibrational CO in HD 100546 from four epochs spanning 2003 January through 2010 December. We show that the equivalent widths of the CO lines vary during this time period with the v = 1–0 CO lines brightening more than the UV fluoresced lines from the higher vibrational states.While the spectroastrometric signal of the hot band lines remains constant during this period, the spectroastrometric signal of the v = 1–0 lines varies substantially. At all epochs, the spectroastrometric signals of the UV fluoresced lines are consistent with the signal one would expect from gas in an axisymmetric …

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High-Resolution Near-Infrared Spectroscopy Of Hd 100546. I. Analysis Of Asymmetric Ro-Vibrational Oh Emission Lines, Joseph Liskowsky, Sean D. Brittain, Joan R. Najita, John S. Carr, Greg W. Doppman, Matthew R. Troutman Nov 2013

High-Resolution Near-Infrared Spectroscopy Of Hd 100546. I. Analysis Of Asymmetric Ro-Vibrational Oh Emission Lines, Joseph Liskowsky, Sean D. Brittain, Joan R. Najita, John S. Carr, Greg W. Doppman, Matthew R. Troutman

Publications

We present observations of ro-vibrational OH and CO emission from the Herbig Be star HD 100546. The emission from both molecules arises from the inner region of the disk extending from approximately 13 AU from the central star. The velocity profiles of the OH lines are narrower than the velocity profile of the [O i] λ6300 line, indicating that the OH in the disk is not cospatial with the Oi. This suggests that the inner optically thin region of the disk is largely devoid of molecular gas. Unlike the ro-vibrational CO emission lines, the OH lines are highly asymmetric. We …

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Broad Iron Lines In Neutrons Stars: Dynamical Broadening Or Wind Scattering?, E. M. Cackett, Jon M. Miller Nov 2013

Broad Iron Lines In Neutrons Stars: Dynamical Broadening Or Wind Scattering?, E. M. Cackett, Jon M. Miller

Physics and Astronomy Faculty Research Publications

Broad iron emission lines are observed in many accreting systems from black holes in active galactic nuclei and X-ray binaries to neutron star low-mass X-ray binaries. The origin of the line broadening is often interpreted as due to dynamical broadening and relativistic effects. However, alternative interpretations have been proposed, included broadening due to Compton scattering in a wind or accretion disk atmosphere. Here we explore the observational signatures expected from broadening in a wind, in particular that the iron line width should increase with an increase in the column density of the absorber (due to an increase in the number …

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Calculating Time Lags From Unevenly Sampled Light Curves, A. Zoghbi, C. Reynolds, E. M. Cackett Nov 2013

Calculating Time Lags From Unevenly Sampled Light Curves, A. Zoghbi, C. Reynolds, E. M. Cackett

Physics and Astronomy Faculty Research Publications

Timing techniques are powerful tools to study dynamical astrophysical phenomena. In the X-ray band, they offer the potential of probing accretion physics down to the event horizon. Recent work has used frequency- and energy-dependent time lags as tools for studying relativistic reverberation around the black holes in several Seyfert galaxies. This was achieved due to the evenly sampled light curves obtained using XMM-Newton. Continuously sampled data are, however, not always available and standard Fourier techniques are not applicable. Here, building on the work of Miller et al., we discuss and use a maximum likelihood method to obtain frequency-dependent lags that …

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0112+1703_Nir_Gnirs, Michael C. Liu Nov 2013

0112+1703_Nir_Gnirs, Michael C. Liu

Publications and Research

No abstract provided.

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2114-2251_Nir_Gnirs, Michael C. Liu Nov 2013

2114-2251_Nir_Gnirs, Michael C. Liu

Publications and Research

No abstract provided.

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Absolute Properties Of The Eclipsing Binary Vv Corvi, Francis C. Fekel, Gregory W. Henry, James R. Sowell Oct 2013

Absolute Properties Of The Eclipsing Binary Vv Corvi, Francis C. Fekel, Gregory W. Henry, James R. Sowell

Information Systems and Engineering Management Research Publications

We have obtained red-wavelength spectroscopy and Johnson B and V differential photoelectric photometry of the eclipsing binary VV Crv = HR 4821. The system is the secondary of the common proper motion double star ADS 8627, which has a separation of 52. VV Crv has an orbital period of 3.144536 days and a low but non-zero eccentricity of 0.085. With the Wilson–Devinney program we have determined a simultaneous solution of our spectroscopic and photometric observations. Those orbital elements produce masses of M1 = 1.978 ± 0.010 M☉ and M2 = 1.513 ± 0.008 M☉, and …

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Finding Rare Agn: Xmm-Newton And Chandra Observations Of Sdss Stripe 82, Stephanie M. Lamassa, C. Megan Urry, Nico Cappelluti, Francesca Civano Oct 2013

Finding Rare Agn: Xmm-Newton And Chandra Observations Of Sdss Stripe 82, Stephanie M. Lamassa, C. Megan Urry, Nico Cappelluti, Francesca Civano

Dartmouth Scholarship

We have analysed the XMM–Newton and Chandra data overlapping ∼16.5 deg2 of Sloan Digital Sky Survey Stripe 82, including ∼4.6 deg2 of proprietary XMM–Newton data that we present here. In total, 3362 unique X-ray sources are detected at high significance. We derive the XMM–Newton number counts and compare them with our previously reported Chandra logN–logS relations and other X-ray surveys. The Stripe 82 X-ray source lists have been matched to multiwavelength catalogues using a maximum likelihood estimator algorithm. We discovered the highest redshift (z = 5.86) quasar yet identified in an X-ray survey. We …

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Using Open Datasets And Simulations In Laboratories, Jim Crumley Oct 2013

Using Open Datasets And Simulations In Laboratories, Jim Crumley

Physics Faculty Publications

While advances in instrumentation physics have made many areas more accessible to undergraduate physics laboratories, other areas are still beyond reach. Open data sets and simulations can open up some other frontiers of physics, such as Space Physics and Astronomy. In this talk, I will give an overview of some resources for open data and simulations, and then describe my experiences using these tools in both introductory and advanced labs in our curriculum.

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Hubble Space Telescope Hot Jupiter Transmission Spectral Survey: A Detection Of Na And Strong Optical Absorption In Hat-P-1b, Nikolay Nikolov, David K. Sing, Frederic Pont, Adam S. Burrows, Jonathan J. Fortney, Gilda E. Ballester, Thomas M. Evans, Catherine M. Huitson, Hannah R. Wakeford, Paul A. Wilson, Suzanne Aigrain, Drake Deming, Neale P. Gibson, Gregory W. Henry, Heather Knutson, Alain Lecavelier Des Etangs, Adam P. Showman, Alfred Vidal-Madjar, Kevin J. Zahnle Oct 2013

Hubble Space Telescope Hot Jupiter Transmission Spectral Survey: A Detection Of Na And Strong Optical Absorption In Hat-P-1b, Nikolay Nikolov, David K. Sing, Frederic Pont, Adam S. Burrows, Jonathan J. Fortney, Gilda E. Ballester, Thomas M. Evans, Catherine M. Huitson, Hannah R. Wakeford, Paul A. Wilson, Suzanne Aigrain, Drake Deming, Neale P. Gibson, Gregory W. Henry, Heather Knutson, Alain Lecavelier Des Etangs, Adam P. Showman, Alfred Vidal-Madjar, Kevin J. Zahnle

Information Systems and Engineering Management Research Publications

We present an optical to near-infrared transmission spectrum of the hot Jupiter HAT-P-1b, based on Hubble Space Telescope observations, covering the spectral regime from 0.29 to 1.027 μm with Space Telescope Imaging Spectrograph (STIS), which is coupled with a recent Wide Field Camera 3 (WFC3) transit (1.087 to 1.687 μm). We derive refined physical parameters of the HAT-P-1 system, including an improved orbital ephemeris. The transmission spectrum shows a strong absorption signature shortward of 0.55 μm, with a strong blueward slope into the near-ultraviolet. We detect atmospheric sodium absorption at a 3.3σ significance level, but find no evidence for the …

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Discovery Of A New Tev Gamma-Ray Source: Ver J0521+211, P. T. Reynolds, Veritas Oct 2013

Discovery Of A New Tev Gamma-Ray Source: Ver J0521+211, P. T. Reynolds, Veritas

Physical Sciences Publications

We report the detection of a new TeV gamma-ray source, VER J0521+211, based on observations made with the VERITAS imaging atmospheric Cherenkov Telescope Array. These observations were motivated by the discovery of a cluster of >30 GeV photons in the first year of Fermi Large Area Telescope observations. VER J0521+211 is relatively bright at TeV energies, with a mean photon flux of (1.93 ± 0.13stat ± 0.78sys) × 10–11 cm–2 s–1 above 0.2 TeV during the period of the VERITAS observations. The source is strongly variable on a daily timescale across all wavebands, from optical to TeV, with a peak …

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The Role Of Cross-Shock Potential On Pickup Ion Shock Acceleration In The Framework Of Focused Transport Theory, Pingbing Zuo, Ming Zhang, Hamid K. Rassoul Oct 2013

The Role Of Cross-Shock Potential On Pickup Ion Shock Acceleration In The Framework Of Focused Transport Theory, Pingbing Zuo, Ming Zhang, Hamid K. Rassoul

Aerospace, Physics, and Space Science Faculty Publications

The focused transport theory is appropriate to describe the injection and acceleration of low-energy particles at shocks as an extension of diffusive shock acceleration (DSA). In this investigation, we aim to characterize the role of cross-shock potential (CSP) originated in the charge separation across the shock ramp on pickup ion (PUI) acceleration at various types of shocks with a focused transport model. The simulation results of energy spectrum and spatial density distribution for the cases with and without CSP added in the model are compared.With sufficient acceleration time, the focused transport acceleration finally falls into the DSA regime with the …

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Gaussian Representation Of Active Galactic Nuclei, Jeffrey W. Klimes, Matthew Lister Oct 2013

Gaussian Representation Of Active Galactic Nuclei, Jeffrey W. Klimes, Matthew Lister

The Summer Undergraduate Research Fellowship (SURF) Symposium

Active galactic nuclei (AGN) are the areas around the centers of galaxies with high luminosity in much of the electromagnetic spectrum. The existing model of AGN describes the high luminosity as the result of accretion of matter around a black hole at the galaxy’s center. Many AGN generate superluminal jets of density higher than the surrounding interstellar medium. The cause for and mechanics driving the relativistic jets are not well understood. In addition, the jets often change direction decaparsecs away from their associated cores, the cause of which has not been well explained. In order to better understand the mechanics …

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Hst Hot-Jupiter Transmission Spectral Survey: Evidence For Aerosols And Lack Of Tio In The Atmosphere Of Wasp-12b, David K. Sing, Alain Lecavelier Des Etangs, Jonathan J. Fortney, Adam Burrows, Frederic Pont, Hannah R. Wakeford, Gilda E. Ballester, Nikolay Nikolov, Gregory W. Henry, Suzanne Aigrain, Drake Deming, Thomas M. Evans, Neale P. Gibson, Catherine M. Huitson, Heather Knutson, Adam P. Showman, Alfred Vidal-Madjar, Paul A. Wilson, Michael H. Williamson, Kevin J. Zahnle Oct 2013

Hst Hot-Jupiter Transmission Spectral Survey: Evidence For Aerosols And Lack Of Tio In The Atmosphere Of Wasp-12b, David K. Sing, Alain Lecavelier Des Etangs, Jonathan J. Fortney, Adam Burrows, Frederic Pont, Hannah R. Wakeford, Gilda E. Ballester, Nikolay Nikolov, Gregory W. Henry, Suzanne Aigrain, Drake Deming, Thomas M. Evans, Neale P. Gibson, Catherine M. Huitson, Heather Knutson, Adam P. Showman, Alfred Vidal-Madjar, Paul A. Wilson, Michael H. Williamson, Kevin J. Zahnle

Information Systems and Engineering Management Research Publications

We present Hubble Space Telescope (HST) optical transmission spectra of the transiting hot-Jupiter WASP-12b, taken with the Space Telescope Imaging Spectrograph instrument. The resulting spectra cover the range 2900–10 300 Å which we combined with archival Wide Field Camera 3 spectra and Spitzer photometry to cover the full optical to infrared wavelength regions. With high spatial resolution, we are able to resolve WASP-12A's stellar companion in both our images and spectra, revealing that the companion is in fact a close binary M0V pair, with the three stars forming a triple-star configuration. We derive refined physical parameters of the WASP-12 system, …

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Broadband Monitoring Tracing The Evolution Of The Jet And Disk In The Black Hole Candidate X-Ray Binary Maxi J1659-152, A. J. Horst, P. A. Curran, J. C. A. Miller-Jones, J. D. Linford, J. Gorosabel, D. M. Russell, A. De Ugarte Postigo, A. A. Lundgren, G. B. Taylor, D Maitra, S Guziy, T M. Belloni, C Kouveliotou, P G. Jonker, A Kamble, Z Paragi, J Homan, E Kuulkers, J Granot, D Altamirano, M M. Buxton, A Castro-Tirado, R P. Fender, M A. Garrett, N Gehrels, Dieter H. Hartmann, J A. Kennea, H A. Krimm, V Mangano, E Ramirez-Ruiz, P Romano, R.A.M.J. Wijers, R Wijnands, Y J. Yang Oct 2013

Broadband Monitoring Tracing The Evolution Of The Jet And Disk In The Black Hole Candidate X-Ray Binary Maxi J1659-152, A. J. Horst, P. A. Curran, J. C. A. Miller-Jones, J. D. Linford, J. Gorosabel, D. M. Russell, A. De Ugarte Postigo, A. A. Lundgren, G. B. Taylor, D Maitra, S Guziy, T M. Belloni, C Kouveliotou, P G. Jonker, A Kamble, Z Paragi, J Homan, E Kuulkers, J Granot, D Altamirano, M M. Buxton, A Castro-Tirado, R P. Fender, M A. Garrett, N Gehrels, Dieter H. Hartmann, J A. Kennea, H A. Krimm, V Mangano, E Ramirez-Ruiz, P Romano, R.A.M.J. Wijers, R Wijnands, Y J. Yang

Publications

MAXI J1659−152 was discovered on 2010 September 25 as a new X-ray transient, initially identified as a gamma-ray burst, but was later shown to be a new X-ray binary with a blackhole as the most likely compact object. Dips in the X-ray light curves have revealed that MAXI J1659−152 is the shortest period black hole candidate identified to date. Here we present the results of a large observing campaign at radio, submillimetre, near-infrared (nIR), optical and ultraviolet (UV) wavelengths. We have combined this very rich data set with the available X-ray observations to compile a broad-band picture of the evolution …

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Wesleyan's Mark Evans Observatory Designated Official Site, Kim Hill Oct 2013

Wesleyan's Mark Evans Observatory Designated Official Site, Kim Hill

News and Events (Discontinued Series)

No abstract provided.

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Bound Orbits And Virial Theorem In A Dark Energy Universe, Kristen Lackeos Oct 2013

Bound Orbits And Virial Theorem In A Dark Energy Universe, Kristen Lackeos

Von Braun Symposium Student Posters

No abstract provided.

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New Precision Orbits Of Bright Double-Lined Spectroscopic Binaries. Viii. Hr 1528, Hr 6993, 2 Sagittae, And 18 Vulpeculae, Francis C. Fekel, Jocelyn Tomkin, Michael H. Williamson Oct 2013

New Precision Orbits Of Bright Double-Lined Spectroscopic Binaries. Viii. Hr 1528, Hr 6993, 2 Sagittae, And 18 Vulpeculae, Francis C. Fekel, Jocelyn Tomkin, Michael H. Williamson

Information Systems and Engineering Management Research Publications

Improved orbital elements for four A-star double-lined spectroscopic binaries have been determined with numerous new radial velocities. Three of the four systems, HR 1528, 2 Sge, and 18 Vul, have moderately short orbital periods of 7.05, 7.39, and 9.31 days, respectively, and also have circular or nearly circular orbits. Only HR 6993 with a period of 14.68 days has a significantly eccentric orbit. The close visual companion of 2 Sge has been detected spectroscopically, and its velocity measured. The orbital dimensions (a1 sin i and a2 sin i) and minimum masses (m1 sin3 i and m2 sin3 i) of the …

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Current-Sheet-Like Structures In Solar Winds And Their Effects On The Solar Wind Mhd Turbulence, Junxiang Hu, Allison Bratcher Oct 2013

Current-Sheet-Like Structures In Solar Winds And Their Effects On The Solar Wind Mhd Turbulence, Junxiang Hu, Allison Bratcher

Von Braun Symposium Student Posters

No abstract provided.

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Design Reference Space Radiation Environments For Spacecraft Design And Mission Planning, Z Robinson Oct 2013

Design Reference Space Radiation Environments For Spacecraft Design And Mission Planning, Z Robinson

Von Braun Symposium Student Posters

No abstract provided.

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