Physics Commons^™

Jitter Impact On Clock Distribution In Lhc Experiments, S. Baron, Themis Mastoridis, J. Troska, P. Baudrenghien

Physics

The LHC Bunch Clock is one of the most important accelerator signals delivered to the experiments. Being directly derived from the Radio Frequency driving the beams in the accelerator by a simple division of its frequency by a factor of 10, the Bunch Clock signal represents the frequency at which the bunches are crossing each other at each experiment. It is thus used to synchronize all the electronics systems in charge of event detection. Its frequency is around 40.079 MHz, but varies with beam parameters (energy, particle type, etc) by a few hundreds of Hz. The present paper discusses the …

Estimating The R-Value Of Earth's Atmosphere, David Hafemeister

Physics

No abstract provided.

Accretion Properties Of High- And Low-Excitation Young Radio Galaxies, Donghoon Son, Jong-Hak Woo, Sang Chul Kim, Hai Fu, Nozomu Kawakatu, Vardha N. Bennert, Tohru Nagao, Daeseong Park

Physics

Young radio galaxies (YRGs) provide an ideal laboratory to explore the connection between the accretion disk and radio jet thanks to their recent jet formation. We investigate the relationship between the emission-line properties, the black hole accretion rate, and the radio properties using a sample of 34 low-redshift (z < 0.4) YRGs. We classify YRGs as high-excitation galaxies (HEGs) and low-excitation galaxies (LEGs) based on the flux ratio of high-ionization to low-ionization emission lines. Using the Hα luminosities as a proxy of accretion rate, we find that HEGs in YRGs have ~1 dex higher Eddington ratios than LEGs in YRGs, suggesting that HEGs have a higher mass accretion rate or higher radiative efficiency than LEGs. In agreement with previous studies, we find that the luminosities of emission lines, in particular Hα, are correlated with radio core luminosity, suggesting that accretion and young radio activities are fundamentally connected.

Performances And Future Plans Of The Lhc Rf, P. Baudrenghien, T. Mastoridis

Physics

The ramp-up of the LHC operation has been exceptionally fast: from the first acceleration of a single bunch at nominal intensity (1.1E11 p) to 3.5 TeV/c on May 2010, to the accumulation of 11 fb-1 integrated luminosity two years later (June 2012). On the RF side this was made possible by a few key design choices and several developments, that allow reliable LHC operation with 0.35 A DC beam at 4 TeV/c (1380 bunches at 50 ns spacing, 1.5E11 p per bunch). This paper reviews the RF design and presents its performance. Plans are also outlined that would allow operation …

Lhc Impedance Model: Experience With High Intensity Operation In The Lhc, B. Salvant, O. Aberle, G. Arduini, R. Assmann, V. Baglin, M.J. Barnes, P. Baudrenghien, A. Bertarelli, C. Bracco, R. Bruce, X. Buffat, F. Carra, G. Cattenoz, F. Caspers, S. Claudet, H. Day, J. Esteban Mueller, M. Garlasché, L. Gentini, B. Goddard, A. Grudiev, B. Henrist, W. Herr, S. Jakobsen, R. Jones, G. Lanza, L. Lari, T. Mastoridis, E. Métral, N. Mounet, A. Nosych, J.L Nougaret, S. Persichelli, T. Pieloni, A.M. Piguiet, S. Redaelli, F. Roncarolo, G. Rumolo, B. Salvachua, M. Sapinski, E. Shaposhnikova, L. Tavian, M. Timmins, J. Uythoven, A. Vidal, R. Wasef, D. Wollman, A. Burov, S. White

Physics

The CERN Large Hadron Collider (LHC) is now in luminosity production mode and has been pushing its performance in the past months by increasing the proton beam brightness, the collision energy and the machine availability. As a consequence, collective effects have started to become more and more visible and have effectively slowed down the performance increase of the machine. Among these collective effects, the interaction of brighter LHC bunches with the longitudinal and transverse impedance of the machine has been observed to generate beam induced heating, as well as longitudinal and transverse instabilities since 2010. This contribution reviews the current …

Measurements Of The Lhc Longitudinal Resistive Impedance With Beam, J.F. Esteban Muller, T. Argyropoulos, T. Bohl, T. Mastoridis, N. Mounet, G. Papotti, B. Salvant, E. Shaposhnikova, D. Valuch

Physics

The resistive part of the longitudinal impedance contributes to the heat deposition on different elements in the LHC ring including the beam screens, where it has to be absorbed by the cryogenic system and can be a practical limitation for the maximum beam intensity. In this paper, we present the first measurements of the LHC longitudinal resistive impedance with beam, done through synchronous phase shift measurements duringMachine Development sessions in 2012. Synchronous phase shift is measured for different bunch intensities and lengths using the high-precision LHC Beam Phase Module and then data are post-processed to further increase the accuracy. The …

Telescope Assembly Alignment Simulator Performance Optimization, Joshua G. Thompson, Brian Eney, Zaheer Ali, Bob Thompson

STAR Program Research Presentations

The Telescope Assembly Alignment Simulator (TAAS) calibrates scientific instruments (SI’s) that are installed on the Stratospheric Observatory For Infrared Astronomy (SOFIA). An SI’s accuracy is directly dependent on the consistent performance of the TAAS, which has never been fully characterized. After designing various thermal and optical experiments to identify the current unknowns of TAAS, we now have a far better grasp on how the equipment behaves.

The History And Environment Of A Faded Quasar: Hubble Space Telescope Observations Of Hanny’S Voorwerp And Ic 2497, William C. Keel, Chris J. Lintott, Kevin Schawinski, Vardha N. Bennert, Daniel Thomas, Anna Manning, S. Drew Chojnowski, Stuart Lynn

Physics

We present Hubble Space Telescope imaging and spectroscopy, along with supporting Galaxy Evolution Explorer and ground-based data, for the extended high-ionization cloud known as Hanny's Voorwerp, near the spiral galaxy IC 2497. Wide Field Camera 3 images show complex dust absorption near the nucleus of IC 2497. The galaxy core in these data is, within the errors, coincident with the very long baseline interferometry core component marking the active nucleus. Space Telescope Imaging Spectrograph (STIS) optical spectra show the active galactic nucleus (AGN) to be a type 2 Seyfert galaxy of rather low luminosity. The derived ionization parameter log U …

A Local Baseline Of The Black Hole Mass Scaling Relations For Active Galaxies. Ii. Measuring Stellar Velocity Dispersion In Active Galaxies, Chelsea E. Harris, Vardha N. Bennert, Matthew W. Auger, Tommaso Treu, Jong-Hak Woo, Matthew A. Malkan

Physics

We derive spatially resolved stellar kinematics for a sample of 84 out of 104 observed local (0.02 < z < 0.09) galaxies hosting type-1 active galactic nuclei (AGNs), based on long-slit spectra obtained at the 10 m W. M. Keck-1 Telescope. In addition to providing central stellar velocity dispersions, we measure major axis rotation curves and velocity dispersion profiles using three separate wavelength regions, including the prominent Ca H&K, Mg Ib, and Ca II NIR stellar features. In this paper, we compare kinematic measurements of stellar velocity dispersion obtained for different apertures, wavelength regions, and signal-to-noise ratios, and provide recipes to cross-calibrate the measurements reducing systematic effects to the level of a few percent. We also provide simple recipes based on readily observable quantities such as global colors and Ca H&K equivalent width that will allow observers of high-redshift AGN hosts to increase the probability of obtaining reliable stellar kinematic measurements from unresolved spectra in the region surrounding the Ca H&K lines. In subsequent papers in this series, we will combine this unprecedented spectroscopic data set with surface photometry and black hole mass measurements to study in detail the scaling relations between host galaxy properties and black hole mass.

Electronics Development For The Cherenkov Telescope Array, Margaret C. Murphy, Justin Vandenbrouke

STAR Program Research Presentations

Gamma-ray astronomy promises to elucidate the highest-energy particle accelerators in the Universe, and could play a key role in identifying the nature of dark matter. The Cherenkov Telescope Array (CTA), currently in the research and development stage, will study and capture gamma-rays with an order of magnitude grater sensitivity than the instruments already in place. Each telescope in the array will be equipped with dozens of camera modules each containing four TeV Array Readout with GSa/s sampling and Event Trigger (TARGET) chips. TARGET 4 has many internal settings, several of which were tested and analyzed to achieve an optimal operating …

Commissioning Of The Asta Laser Lab With Uv Pulse Length Characterization, Daniel Kelley, Jeff Corbett

STAR Program Research Presentations

The Linac Coherent Light Source (LCLS) at SLAC depends on a photocathode electron gun to provide the linear accelerator with the raw material – electrons – used for making X-ray laser pulses. The photocathode used in the LCLS Injector is a clean copper plate in high vacuum. When the cathode is struck with high energy UV light, electrons are liberated from its surface and then accelerated down the linac with radio-frequency electric fields. These fast-moving bunches of electrons are directed through an undulator magnet to radiate X-ray light.

Although scientists have been using photocathode techniques at SLAC for 25 years, …

Analyzing Wind Turbine Controller Effects On Structure Stress, Leo Groner, Susan Frost

STAR Program Research Presentations

Wind turbines generate electric power from clean renewable sources. They must be robust and reliable. Utility-scale turbines are designed to produce power within a set of wind speed parameters. When winds change, wind turbine blade pitch is used to protect the turbine from over speed damage.

Advanced control algorithms can increase power by extending the performance envelope or they can extend lifetime by reducing stress. A FAST simulation written in MATLAB / Simulink is used to simulate the dynamics of the integrated aerodynamic, mechanical and control subsystems of the turbine. Resonance modes may lead to large amplitude displacements and damage. …

Leds And Astronomy, Britny N. Delp, Stephen M. Pompea

STAR Program Research Presentations

Using a Czerny-Turner spectrometer, 45 different types of outdoor lights were categorized. These spectra were used to determine how useful the light is to human eyes and how dark skies friendly these lights are. Dark skies friendly lighting means that little to no light shines above a right angle to the light, and should emit as little as possible below 500nm (green) wavelengths. The short wavelengths present a problem to astronomers in the form of Rayleigh scattering. The following criterion were used in selecting the best source for urban and rural lighting: color rendition measured by color rendering index (CRI), …

Nearshore Internal Bores And Turbulent Mixing In Southern Monterey Bay, Ryan K. Walter, C. Brock Woodson, Robert S. Arthur, Oliver B. Fringer, Stephen G. Monismith

Physics

We observed transient stratification and mixing events associated with nearshore internal bores in southern Monterey Bay using an array of instruments with high spatial and temporal resolution. The arrival of the bores is characterized by surging masses of dense (cold) water that tend to stratify the water column. The bore is followed by a gradual drop in the temperature throughout the water column over several hours (defined here as the bore period) until a sharp warm-front relaxation, followed by high frequency temperature fluctuations, returns the column back to nearly its original state (defined here as the mixing period). Mixing periods …

The Lick Agn Monitoring Project 2011: Dynamical Modeling Of The Broad-Line Region In Mrk 50, Anna Pancoast, Brendon J. Brewer, Tommaso Treu, Aaron J. Barth, Vardha N. Bennert, Gabriela Canalizo, Alexei V. Filippenko, Elinor L. Gates, Jenny E. Greene, Weidong Li, Matthew A. Malkan, David J. Sand, Daniel Stern, Jong-Hak Woo, Roberto J. Assef, Hyun-Jin Bae, Tabitha Buehler, S. Bradley Cenko, Kelsey I. Clubb, Michael C. Cooper, Aleksandar M. Diamond-Stanic, Kyle D. Hiner, Sebastian F. Hönig, Michael D. Joner, Michael T. Kandrashoff, C. David Laney, Mariana S. Lazarova, A.M. Nierenberg, Dawoo Park, Jeffrey M. Silverman, Donghoon Son, Alessandro Sonnenfeld, Shawn J. Thorman, Erik J. Tollerud, Jonelle L. Walsh, Richard Walters

Physics

We present dynamical modeling of the broad-line region (BLR) in the Seyfert 1 galaxy Mrk 50 using reverberation mapping data taken as part of the Lick AGN Monitoring Project (LAMP) 2011. We model the reverberation mapping data directly, constraining the geometry and kinematics of the BLR, as well as deriving a black hole mass estimate that does not depend on a normalizing factor or virial coefficient. We find that the geometry of the BLR in Mrk 50 is a nearly face-on thick disk, with a mean radius of 9.6^+1.2 _–0.9 light days, a width of the BLR of 6.9 …

Cuore Crystal Validation Runs: Results On Radioactive Contamination And Extrapolation To Cuore Background, F. Alessandria, E. Andreotti, R. Ardito, C. Arnaboldi, F. T. Avignone Iii, M. Balata, I. Bandac, T. I. Banks, G. Bari, J. Beeman, F. Bellini, A. Bersani, M. Biassoni, T. Bloxham, C. Brofferio, A. Bryant, C. Bucci, X. Z. Cai, L. Canonica, S. Capelli, L. Carbone, L. Cardani, M. Carrettoni, N. Chott, M. Clemenza, C. Cosmelli, O. Cremonesi, R. J. Creswick, I. Dafinei, A. Dally, A. De Biasi, M. P. Decowski, M. M. Deninno, A. De Waard, S. Di Domizio, L. Ejzak, R. Faccini, D. Q. Fang, H. A. Farach, E. Ferri, F. Ferroni, E. Fiorini, L. Foggetta, S. J. Freedman, G. Frossati, A. Giachero, L. Gironi, A. Giuliani, P. Gorla, C. Gotti, E. Guardincerri, T. D. Gutierrez, E. E. Haller, K. Han, K. M. Heeger, H. Z. Huang, K. Ichimura, R. Kadel, K. Kazkaz, G. Keppel, L. Kogler, Yu. G. Kolomensky, S. Kraft, D. Lenz, Y. L. Li, X. Liu, E. Longo, Y. G. Ma, C. Maiano, G. Maier, C. Martinez, M. Martinez, R. H. Maruyama, N. Moggi, S. Morganti, S. Newman, S. Nisi, C. Nones, E. B. Norman, A. Nucciotti, F. Orio, D. Orlandi, J. L. Ouellet, M. Pallavicini, V. Palmieri, L. Pattavina, M. Pavan, M. Pedretti, G. Pessina, S. Pirro, E. Previtali, V. Rampazzo, F. Rimondi, C. Rosenfeld, C. Rusconi, C. Salvioni, S. Sangiorgio, D. Schaeffer, N. D. Scielzo, M. Sisti, A. R. Smith, F. Stivanello, L. Taffarello, G. Terenziani, W. D. Tian, C. Tomei, S. Trentalange, G. Ventura, M. Vignati, B. S. Wang, H. W. Wang, C. A. Whitten Jr., T. Wise, A. Woodcraft, N. Xu, L. Zanotti, C. Zarra, B. X. Zhu, S. Zucchelli

Physics

The CUORE Crystal Validation Runs (CCVRs) have been carried out since the end of 2008 at the Gran Sasso National Laboratories, in order to test the performance and the radiopurity of the TeO₂ crystals produced at SICCAS (Shanghai Institute of Ceramics, Chinese Academy of Sciences) for the CUORE experiment. In this work the results of the first 5 validation runs are presented. Results have been obtained for bulk contaminations and surface contaminations from several nuclides. An extrapolation to the CUORE background has been performed.

Approaches To Control Nitrate Pollution In The San Joaquin Watershed, Misgana K. Muleta, Stephen Clayton

Physics

Modeling of the San Joaquin valley using SWAT can give a comprehensive overview of hydrologic traits of the San Joaquin River and its tributaries, specifically for nutrients like nitrate. The San Joaquin valley is a site of intense modeling interest and policy making, as the San Joaquin River joins the Sacramento River to feed into the Delta. The environmental impact of dissolved oxygen on aquatic life on the Delta is a particularly key concern (Quinn 2000). The San Joaquin watershed also represents considerable investment in agriculture on the valley floor and has been studied for nitrate, sediment, and salinity concerns …

Lhc One-Turn Delay Feedback Commissioning, T. Mastoridis, P. Baudrenghien, J. Molendijk

Physics

The LHC One-Turn delay FeedBack (OTFB) is an FPGA based feedback system part of the LHC cavity controller, which produces gain only around the revolution frequency (frev = 11.245 kHz) harmonics. As such, it helps reduce the transient beam loading and effective cavity impedance. Consequently, it increases the stability margin for Longitudinal Coupled Bunch Instabilities driven by the cavity impedance at the fundamental and allows reliable operation at higher beam currents. The OTFB was commissioned on all sixteen cavities in mid-October 2011 and has been used in operation since. The commissioning procedure and algorithms for setting-up are presented. The resulting …

Proposal For An Rf Roadmap Towards Ultimate Intensity In The Lhc, P. Baudrenghien, T. Mastoridis

Physics

The LHC currently operates with 1380 bunches at 50 ns spacing and 1.4 1011 p per bunch (0.35A DC). In this paper the RF operation with ultimate bunch intensity (1.7 1011 p per bunch) and 25 ns spacing (2808 bunches per beam) summing up to 0.86A DC is presented. With the higher beam current, the demanded klystron power will be increased and the longitudinal stability margin reduced. One must also consider the impact of a klystron trip (voltage and power transients in the three turns latency before the beam is actually dumped). In this work a scheme is proposed that …

Evaluating Alternative Hydraulic Solutions To Limit Nutrient Contamination Of An Aquifer In Southern California Read More: Http://Ascelibrary.Org/Doi/Abs/10.1061/9780784412312.009, Misgana K. Muleta, Jake M. Perry

Physics

Many small communities depend on groundwater sources for drinking water and they often use septic tanks for wastewater treatment and disposal. Nitrate and other pollutants leaking from poorly designed septic tank systems can percolate to the aquifers and alter quality of the groundwater. This study describes a groundwater model developed using Visual MODFLOW for an aquifer that is used as a water supply source for the communities of Beaumont and Cherry Valley, CA. The aquifer has been contaminated by nitrates leaking from septic tank systems. The model will assist in clarifying the extent of interactions between nitrate pollutants, percolation from …

Uncertainty Analysis And Calibration Of Swmm Using A Formal Bayesian Methodology Read More: Http://Ascelibrary.Org/Doi/Abs/10.1061/9780784412312.060, Misgana K. Muleta

Physics

Importance of uncertainty analysis (UA) to estimate the degree of reliability associated with model predictions is being understood. Consequently, literature that describes various Bayesian methods for the assessment of parameter and model predictive uncertainty has been steadily rising. Applications dealing with urban stormwater management are, however, very limited. This study demonstrates successful application of a formal Bayesian methodology for UA of the U.S. EPA Stormwater Management Model (SWMM), a widely used urban stormwater management model, and illustrates the methodology using a highly urbanized watershed in southern California. DREAM_(ZS), a recently developed effective and efficient sampling algorithm, and a …

A Formal, Bayesian Approach For Uncertainty Analysis Of A Watershed Model, Misgana K. Muleta

Physics

Uncertainty analysis (UA) has received substantial attention in water resources during the last decade. Bayesian approaches are often preferred for UA. This study describes a formal Bayesian approach for the assessment of parameter uncertainty and predictive uncertainty using a spatially distributed hydrologic model and will demonstrate its application using data from a well monitored experimental watershed. A Markov-Chain Monte Carlo (MCMC) scheme has been used to sample posterior parameter distributions. A formal, flexible likelihood function that explicitly accounts for heteroscedasticity, temporal correlation and non-normality of simulation residuals has been used to describe closeness of the simulated and observed streamflow. Performance …

Computing Accurate Age And Distance Factors In Cosmology, Jodi L. Christiansen, Andrew Siver

Physics

As the universe expands astronomical observables such as brightness and angular size on the sky change in ways that differ from our simple Cartesian expectation. We show how observed quantities depend on the expansion of space and demonstrate how to calculate such quantities using the Friedmann equations. The general solution to the Friedmann equations requires a numerical solution which is easily coded in any computing language (including EXCEL). We use these numerical calculations in four student projects that help to build their understanding of high-redshift phenomena and cosmology. Instructions for these projects are available as supplementary materials.

Search For Double-Β Decay Of 130te To The First 0+ Excited State Of 130xe With The Cuoricino Experiment Bolometer Array, E. Andreotti, C. Arnaboldi, F.T. Avignone Iii, M. Balata, I. Bandac, M. Barucci, J.W. Beeman, F. Bellini, C. Brofferio, A. Bryant, C. Bucci, L. Canonica, S. Capelli, L. Carbone, M. Carrettoni, M. Clemenza, O. Cremonesi, R.J. Creswick, S. Di Domizio, M.J. Dolinski, L. Ejzak, R. Faccini, H.A. Farach, E. Ferri, E. Fiorini, L. Foggetta, A. Giachero, L. Gironi, A. Giuliani, P. Gorla, E. Guardincerri, T.D. Gutierrez, E.E. Haller, K. Kazkaz, L. Kogler, S. Kraft, C. Maiano, C. Martinez, M. Martinez, R.H. Maruyama, S. Newman, S. Nisi, C. Nones, E.B. Norman, A. Nucciotti, F. Orio, M. Pallavicini, V. Palmieri, L. Pattavina, M. Pavan, M. Pedretti, G. Pessina, S. Pirro, E. Previtali, L. Risegari, C. Rosenfeld, C. Rusconi, C. Salvioni, S. Sangiorgio, D. Schaeffer, N.D. Scielzo, M. Sisti, A.R. Smith, C. Tomei, G. Ventura, M. Vignati

Physics

The CUORICINO experiment was an array of 62 TeO2 single-crystal bolometers with a total 130Te mass of 11.3kg. The experiment finished in 2008 after more than 3 yr of active operating time. Searches for both 0ν and 2ν double-β decay to the first excited 0+ state in 130Xe were performed by studying different coincidence scenarios. The analysis was based on data representing a total exposure of N(130Te)⋅t=9.5×1025yr. No evidence for a signal was found. The resulting lower limits on the half-lives are T2ν12(130Te→130Xe∗)>1.3×1023yr (90% C.L.), and T0ν12(130Te→130Xe∗)>9.4×1023yr (90% CL).

Reflections On The Forum At Forty, David Hafemeister

Physics

No abstract provided.

The Lick Agn Monitoring Project 2011: Recalibrating Single-Epoch Virial Black Hole Mass Estimates, Daeseong Park, Jong-Hak Woo, Tommaso Treu, Aaron J. Barth, Misty C. Bentz, Vardha N. Bennert, Gabriela Canalizo, Alexei V. Filippenko, Elinor Gates, Jenny E. Greene, Matthew A. Malkan, Jonelle Walsh

Physics

We investigate the calibration and uncertainties of black hole (BH) mass estimates based on the single-epoch (SE) method, using homogeneous and high-quality multi-epoch spectra obtained by the Lick Active Galactic Nucleus (AGN) Monitoring Project for nine local Seyfert 1 galaxies with BH masses <10⁸ M _☉. By decomposing the spectra into their AGNs and stellar components, we study the variability of the SE Hβ line width (full width at half-maximum intensity, FWHM_Hβ or dispersion, σ_Hβ) and of the AGN continuum luminosity at 5100 Å (L ₅₁₀₀). From the distribution of the "virial products" ( …

The Galaxy Zoo Survey For Giant Agn-Ionized Clouds: Past And Present Black Hole Accretion Events, William C. Keel, Drew Chojnowski, Vardha N. Bennert, Kevin Schawinski, Chris J. Lintott, Stuart Lynn, Anna Pancoast, Chelsea Harris, A. M. Nierenberg, Alessandro Sonnenfeld, Richard Proctor

Physics

Some active galactic nuclei (AGN) are surrounded by extended emission-line regions (EELRs), which trace both the illumination pattern of escaping radiation and its history over the light travel time from the AGN to the gas. From a new set of such EELRs, we present evidence that the AGN in many Seyfert galaxies undergo luminous episodes 0.2–2 ×105 years in duration. Motivated by the discovery of the spectacular nebula known as Hanny’s Voorwerp, ionized by a powerful AGN which has apparently faded dramatically within ≈ 105 years, Galaxy Zoo volunteers have carried out both targeted and serendipitous searches for similar emission-line …

Novel Magnetite-Producing Magnetotactic Bacteria Belonging To The Gammaproteobacteria, Christopher T. Lefèvre, Nathan Viloria, Marian L. Schmidt, Mihály Pósfai, Richard B. Frankel, Dennis A. Bazylinski

Physics

Two novel magnetotactic bacteria (MTB) were isolated from sediment and water collected from the Badwater Basin, Death Valley National Park and southeastern shore of the Salton Sea, respectively, and were designated as strains BW-2 and SS-5, respectively. Both organisms are rod-shaped, biomineralize magnetite, and are motile by means of flagella. The strains grow chemolithoautotrophically oxidizing thiosulfate and sulfide microaerobically as electron donors, with thiosulfate oxidized stoichiometrically to sulfate. They appear to utilize the Calvin–Benson–Bassham cycle for autotrophy based on ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) activity and the presence of partial sequences of RubisCO genes. Strains BW-2 and SS-5 biomineralize chains of octahedral …

Forum History At Forty (2012), David Hafemeister

Physics

Physics is a major component of many of society's difficult issues: nuclear arms and their proliferation, energy shortages and energy impacts, climate change, and technical innovation. Because physics principles underlie so many of these societal issues and because physics offers a way to quantify some aspects of them, members of the American Physical Society (APS) should be encouraged to understand, analyze and debate them. This is precisely why APS members formed the Forum on Physics and Society (FPS). To those of us who have been involved in FPS affairs for a long time, it seems like only yesterday that we …

Very Early Ultraviolet And Optical Observations Of The Type Ia Supernova 2009ig, Ryan J. Foley, P. J. Challis, A. V. Filippenko, M. Ganeshalingam, W. Landsman, W. Li, G. H. Marion, J. M. Silverman, R. L. Beaton, V. N. Bennert, S. B. Cenko, M. Childress, P. Guhathakurta, L. Jiang, J. S. Kalirai, R. P. Kirshner, A. Stockton, E. J. Tollerud, J. Vinkó, J. C. Wheeler, J.-H. Woo

Physics

Supernova (SN) 2009ig was discovered 17 hr after explosion by the Lick Observatory Supernova Search, promptly classified as a normal Type Ia SN (SN Ia), peaked at V = 13.5 mag, and was equatorial, making it one of the foremost SNe for intensive study in the last decade. Here, we present ultraviolet (UV) and optical observations of SN 2009ig, starting about 1 day after explosion until around maximum brightness. Our data include excellent UV and optical light curves, 25 premaximum optical spectra, and 8 UV spectra, including the earliest UV spectrum ever obtained of an SN Ia. SN 2009ig is …