# Astrophysics and Astronomy Commons™

## All Articles in Astrophysics and Astronomy

6,533 full-text articles. Page 193 of 201.

2010 Brigham Young University - Provo

#### Simulating The Fticr-Ms Signal Of A Decaying Beryllium-7 Ion Plasma In A 2d Electrostatic Pic Code, Michael Takeshi Nakata

##### Theses and Dissertations

Beryllium-7 (Be-7) only decays by electron capture into lithium-7 (Li-7) with a half life of 53 days. We study the effect of ionization on this decay rate. We do so by trapping a Be-7 ion plasma in a cylindrical Malmberg-Penning trap and measuring Be-7 and Li-7 concentrations as functions of time by using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). We have simulated these signals in a 2-dimensional electrostatic particle-in-cell (PIC) code. The two spectrum peaks merge at high ion densities whereas at low ion densities they can be resolved. The merged peak shifts linearly according to the relative ...

Microwave Kinetic Inductance Detector Camera Development For Millimeter-Wave Astrophysics, 2010 University of Colorado, Boulder

#### Microwave Kinetic Inductance Detector Camera Development For Millimeter-Wave Astrophysics, James Andrew Schlaerth

##### Physics Graduate Theses & Dissertations

This thesis describes my contribution to the design, assembly and testing required for a camera using antenna-coupled Microwave Kinetic Inductance Detectors (MKIDs). MKIDs are super-conducting resonators in which the resonance frequency and quality factor are sensitive measures of Cooper pairs broken by incident radiation. The MKID camera, called the Multicolor Submillimeter Inductance Camera (MUSIC), is built to detect and characterize the physics of dusty submillimeter galaxies, the primary component of the far-infrared background discovered by the COBE satellite. The camera will have 576 pixels sensitive to 4 colors simultaneously in the range of 150-360 GHz. With these bands, combined with ...

The Determination Of Reddening From Intrinsic Vr Colors Of Rr Lyrae Stars, 2010 Dartmouth College

#### The Determination Of Reddening From Intrinsic Vr Colors Of Rr Lyrae Stars, Andrea Kunder, Brian Chaboyer, Andrew Layden

##### Open Dartmouth: Faculty Open Access Scholarship

New R-band observations of 21 local field RR Lyrae variable stars are used to explore the reliability of minimum light (VR) colors as a tool for measuring interstellar reddening. For each star, R-band intensity mean magnitudes and light amplitudes are presented. Corresponding V-band light curves from the literature are supplemented with the new photometry, and (VR) colors at minimum light are determined for a subset of these stars as well as for other stars in the literature. Two different definitions of minimum light color are examined, one which uses a Fourier decomposition to the V ...

The Acs Survey Of Galactic Globular Clusters. Viii. Effects Of Environment On Globular Cluster Global Mass Functions, 2010 Whitman College

#### The Acs Survey Of Galactic Globular Clusters. Viii. Effects Of Environment On Globular Cluster Global Mass Functions, Nathaniel E. Q. Paust, I. Neill Reid, Giampaolo Piotto, Antonio Aparicio, Jay Anderson, Ata Sarajedini, Luigi R. Bedin, Brian Chaboyer

##### Open Dartmouth: Faculty Open Access Scholarship

We have used observations obtained as part of the Hubble Space Telescope/ACS Survey of Galactic Globular Clusters to construct global present-day mass functions for 17 globular clusters utilizing multi-mass King models to extrapolate from our observations to the global cluster behavior. The global present-day mass functions for these clusters are well matched by power laws from the turnoff, ≈0.8 M , to 0.2-0.3 M on the lower main sequence. The slopes of those power-law fits, α, have been correlated with an extensive set of intrinsic and extrinsic cluster properties to investigate which parameters may influence the form ...

A New Method For Describing The Horizontal Electric Field Induced By A Lightning Strike Return Stroke, 2010 Trinity University

#### A New Method For Describing The Horizontal Electric Field Induced By A Lightning Strike Return Stroke, S L. Meredith, S K. Earles, Niescja E. Turner

##### Physics and Astronomy Faculty Research

No abstract provided.

Origins Of The Extragalactic Background At 1mm From A Combined Analysis Of The Aztec And Mambo Data In Goods-N, 2010 University of Massachusetts - Amherst

#### Origins Of The Extragalactic Background At 1mm From A Combined Analysis Of The Aztec And Mambo Data In Goods-N, Kyle Penner, Alexandra Pope, Edward Chapin, Thomas Greve, Frank Bertoldi, Mark Brodwin, Ranga-Ram Chary, Christopher Conselice, Kristen Coppin, Mauro Giavalisco, David Hughes, Rob Ivison, Thushara Perera, Douglas Scott, Kimberly Scott, Grant Wilson

##### Scholarship

We present a study of the cosmic infrared background, which is a measure of the dust obscured activity in all galaxies in the Universe. We venture to isolate the galaxies responsible for the background at 1mm; with spectroscopic and photometric redshifts we constrain the redshift distribution of these galaxies. We create a deep 1.16mm map (sigma ~ 0.5mJy) by combining the AzTEC 1.1mm and MAMBO 1.2mm datasets in GOODS-N. This combined map contains 41 secure detections, 13 of which are new. By averaging the 1.16mm flux densities of individually undetected galaxies with 24um flux densities > 25uJy ...

Observations Of Ozone Production In A Dissipating Tropical Convective Cell During Tc4, 2010 Valparaiso University

#### Observations Of Ozone Production In A Dissipating Tropical Convective Cell During Tc4, Gary A. Morris, A. M. Thompson, K. E. Pickering, S. Chen, E. J. Bucsela, P. A. Kucera

##### Physics and Astronomy Faculty Publications

From 13 July–9 August 2007, 25 ozonesondes were launched from Las Tablas, Panama as part of the Tropical Composition, Cloud, and Climate Coupling (TC4) mission. On 5 August, a strong convective cell formed in the Gulf of Panama. World Wide Lightning Location Network (WWLLN) data indicated 563 flashes (09:00–17:00 UTC) in the Gulf. NO2 data from the Ozone Monitoring Instrument (OMI) show enhancements, suggesting lightning production of NOx. At 15:05 UTC, an ozonesonde ascended into the southern edge of the now dissipating convective cell as it moved west across the Azuero Peninsula. The balloon oscillated ...

Globe Walk, 2010 University of Massachusetts - Amherst

#### Globe Walk, Rob Snyder

##### IPY STEM Polar Connections

A “Globe Walk” can be used as a demonstration or classroom activity to guide students toward a better understanding of the affects that Earth’s axial tilt, rotation on Earth’s axis, and orbital motion have on the angles of incidence of sunlight, the lengths of daytimes, and solar insolation.

Computational Fluctuating Fluid Dynamics, 2010 San Jose State University

#### Computational Fluctuating Fluid Dynamics, Alejandro Garcia, John B. Bell, Sarah Williams

##### Alejandro Garcia

This paper describes the extension of a recently developed numerical solver for the Landau-Lifshitz Navier-Stokes (LLNS) equations to binary mixtures in three dimensions. The LLNS equations incorporate thermal fluctuations into macroscopic hydrodynamics by using white-noise fluxes. These stochastic PDEs are more complicated in three dimensions due to the tensorial form of the correlations for the stochastic fluxes and in mixtures due to couplings of energy and concentration fluxes (e.g., Soret effect). We present various numerical tests of systems in and out of equilibrium, including time-dependent systems, and demonstrate good agreement with theoretical results and molecular simulation

A Hybrid Particle-Continuum Method For Hydrodynamics Of Complex Fluids, 2010 San Jose State University

#### A Hybrid Particle-Continuum Method For Hydrodynamics Of Complex Fluids, Alejandro Garcia, Aleksandar Donev, John B. Bell, Berni Alder

##### Alejandro Garcia

A previously developed hybrid particle-continuum method [J. B. Bell, A. Garcia, and S. A. Williams, Multiscale Model. Simul., 6 (2008), pp. 1256–1280] is generalized to dense fluids and two- and three-dimensional flows. The scheme couples an explicit fluctuating compressible Navier–Stokes solver with the isotropic direct simulation Monte Carlo (DSMC) particle method [A. Donev, A. L. Garcia, and B. J. Alder, J. Stat. Mech. Theory Exp., 2009 (2009), article P11008]. To achieve bidirectional dynamic coupling between the particle (microscale) and continuum (macroscale) regions, the continuum solver provides state-based boundary conditions to the particle subdomain, while the particle solver provides ...

The Horizontal Electric Field Induced By A Lightning Return Stroke, 2010 Trinity University

#### The Horizontal Electric Field Induced By A Lightning Return Stroke, S L. Meredith, S K. Earles, Niescja E. Turner

##### Physics and Astronomy Faculty Research

Problem statement: Develop a new formula which describes the horizontal electric field induced by a lightning return stroke in contact with an imperfect conductive surface. Approach: A new method for describing the horizontal electric field induced by a lightning return stroke will be presented. The method presented here had utilized an approach which purposely downplayed the physics of how image theory was employed in the presence of an imperfect conductive surface. It did so by adopting a technique which had focused on the geometry that existed between the lightning channel and surface ground. In doing so, new expressions for surface ...

Observations Of Ozone Production In A Dissipating Tropical Convective Cell During Tc4, 2010 Valparaiso University

#### Observations Of Ozone Production In A Dissipating Tropical Convective Cell During Tc4, Gary A. Morris, A. M. Thompson, K. E. Pickering, S. Chen, E. J. Bucsela, P. A. Kucera

##### Gary A. Morris

From 13 July–9 August 2007, 25 ozonesondes were launched from Las Tablas, Panama as part of the Tropical Composition, Cloud, and Climate Coupling (TC4) mission. On 5 August, a strong convective cell formed in the Gulf of Panama. World Wide Lightning Location Network (WWLLN) data indicated 563 flashes (09:00–17:00 UTC) in the Gulf. NO2 data from the Ozone Monitoring Instrument (OMI) show enhancements, suggesting lightning production of NOx. At 15:05 UTC, an ozonesonde ascended into the southern edge of the now dissipating convective cell as it moved west across the Azuero Peninsula. The balloon oscillated ...

Unveiling The Nature Of Submillimeter Galaxy Sxdf 850.6 (Vol 711, Pg 974, 2010), 2010 University of Massachusetts - Amherst

#### Unveiling The Nature Of Submillimeter Galaxy Sxdf 850.6 (Vol 711, Pg 974, 2010), B Hatsukade, D Iono, T Yoshikawa, M Akiyama, Js Dunlop, Rj Ivison, Ab Peck, S Ikarashi, A Biggs, H Ezawa, H Hanami, P Ho, Dh Hughes, R Kawabe, K Kohno, S Matsushita, K Nakanishi, N Padilla, G Petitpas, Y Tamura, J Wagg, Dj Wilner, Gw Wilson, T Yamada, Min Yun

##### Astronomy Department Faculty Publication Series

We present an 880 μm Submillimeter Array (SMA) detection of the submillimeter galaxy SXDF 850.6. SXDF 850.6 is a bright source (S 850 μm = 8 mJy) detected in the SCUBA Half Degree Extragalactic Survey and has multiple possible radio counterparts in its deep radio image obtained at the VLA. Our new SMA detection finds that the submillimeter emission coincides with the brightest radio emission that is found ~8'' north of the coordinates determined from SCUBA. Despite the lack of detectable counterparts in deep UV/optical images, we find a source at the SMA position in near-infrared and longer ...

Galactic Outflows And The Kinematics Of Damped Lyman Alpha Absorbers, 2010 University of Massachusetts - Amherst

#### Galactic Outflows And The Kinematics Of Damped Lyman Alpha Absorbers, S Hong, N Katz, R Dave, M Fardal, D Keres, B Oppenheimer

##### Astronomy Department Faculty Publication Series

The kinematics of damped Lyman alpha absorbers (DLAs) are difficult to reproduce in hierarchical galaxy formation models, particularly the preponderance of wide systems. We investigate DLA kinematics at z=3 using high-resolution cosmological hydrodynamical simulations that include a heuristic model for galactic outflows. Without outflows, our simulations fail to yield enough wide DLAs, as in previous studies. With outflows, predicted DLA kinematics are in much better agreement with observations. Comparing two outflow models, we find that a model based on momentum-driven wind scalings provides the best match to the observed DLA kinematic statistics of Prochaska & Wolfe. In this model, DLAs ...

Extinction Toward The Compact Hii Regions G-0.02-0.07, 2010 University of Massachusetts - Amherst

#### Extinction Toward The Compact Hii Regions G-0.02-0.07, Ea Mills, Mr Morris, Cc Lang, A Cotera, H Dong, Qd Wang, Sr Stolovy

##### Astronomy Department Faculty Publication Series

The four HII regions in the Sgr A East complex: A, B, C, and D, represent evidence of recent massive star formation in the central ten parsecs. Using Paschen-alpha images taken with HST and 8.4 GHz VLA data, we construct an extinction map of A-D, and briefly discuss their morphology and location.

Hst Pa Survey Of The Galactic Center – Searching The Missing Young Stellar Populations Within The Galactic Center, 2010 University of Massachusetts - Amherst

#### Hst Pa Survey Of The Galactic Center – Searching The Missing Young Stellar Populations Within The Galactic Center, H Dong, Qd Wang, A Cortera, S Stolovy, Mr Morris, J Mauerhan, Ea Mills, G Schneider, C Lang

##### Astronomy Department Faculty Publication Series

We present preliminary results of our \hst Pa$\alpha$ survey of the Galactic Center (\gc), which maps the central 0.65$\times$0.25 degrees around Sgr A*. This survey provides us with a more complete inventory of massive stars within the \gc, compared to previous observations. We find 157 Pa$\alpha$ emitting sources, which are evolved massive stars. Half of them are located outside of three young massive star clusters near Sgr A*. The loosely spatial distribution of these field sources suggests that they are within less massive star clusters/groups, compared to the three massive ones. Our Pa ...

100 M And 160 M Emission As Resolved Star–Formation Rate Estimators In M33 (Herm33es, 2010 University of Massachusetts - Amherst

#### 100 M And 160 M Emission As Resolved Star–Formation Rate Estimators In M33 (Herm33es, M Boquien, D Calzetti

##### Astronomy Department Faculty Publication Series

Context. Over the past few years several studies have provided estimates of the SFR (star–formation rate) or the total infrared luminosity from just one infrared band. However these relations are generally derived for entire galaxies, which are known to contain a large scale diuse emission that is not necessarily related to the latest star–formation episode. Aims. We provide new relations to estimate the SFR from resolved star–forming regions at 100 m and 160 m. Methods. We select individual star–forming regions in the nearby (840 kpc) galaxy M33. We estimate the SFR combining the emission in H ...

2010 University of Massachusetts - Amherst

#### X-Raying Galaxies: A Chandra Legacy, Qd Wang

##### Astronomy Department Faculty Publication Series

This presentation reviews Chandra's major contribution to the understanding of nearby galaxies.
After a brief summary on signicant advances in characterizing various types of discrete X-ray
sources, the presentation focuses on the global hot gas in and around galaxies, especially normal
ones like our own. The hot gas is a product of stellar and AGN feedback | the least understood
part in theories of galaxy formation and evolution. Chandra observations have led to the rst
characterization of the spatial, thermal, chemical, and kinetic properties of the gas in our Galaxy.
The gas is concentrated around the Galactic bulge and disk ...

The Lthe Luminosity, Mass, And Age Distributions Of Compact Star Clusters In M83 Based On Hubble Space Telescope/Wide Field Camera 3 Observations, 2010 University of Massachusetts - Amherst

#### The Lthe Luminosity, Mass, And Age Distributions Of Compact Star Clusters In M83 Based On Hubble Space Telescope/Wide Field Camera 3 Observations, R Chandar, B Whitmore, H Kim, C Kaleida, M Mutchler, D Calzetti

##### Astronomy Department Faculty Publication Series

The newly installed Wide Field Camera 3 (WFC3) on the Hubble Space Telescope has been used to obtain multi-band images of the nearby spiral galaxy M83. These new observations are the deepest and highest resolution images ever taken of a grand-design spiral, particularly in the near-ultraviolet, and allow us to better differentiate compact star clusters from individual stars and to measure the luminosities of even faint clusters in the U band. We find that the luminosity function (LF) for clusters outside of the very crowded starburst nucleus can be approximated by a power law, dN/dL vprop L α, with ...

Understanding Global Galactic Star Formation, 2010 University of Massachusetts - Amherst

#### Understanding Global Galactic Star Formation, P Scowen, R Jansen, M Beasley, D Calzetti

##### Astronomy Department Faculty Publication Series

We propose to the community a comprehensive UV/optical/NIR imaging survey of Galactic star formation regions to probe all aspects of the star formation process. The primary goal of such a study is to understand the evolution of circumstellar protoplanetary disks and other detailed aspects of star formation in a wide variety of different environments. This requires a comprehensive emission-line survey of nearby star-forming regions in the Milky Way, where a high spatial resolution telescope+camera will be capable of resolving circumstellar material and shock structures. In addition to resolving circumstellar disks themselves, such observations will study shocks in ...