Flux and brightness calculations for various synchrotron radiation sources

International Nuclear Information System (INIS)

Weber, J.M.; Hulbert, S.L.

1991-11-01

Synchrotron radiation (SR) storage rings are powerful scientific and technological tools. The first generation of storage rings in the US., e.g., SURF (Washington, D.C.), Tantalus (Wisconsin), SSRL (Stanford), and CHESS (Cornell), revolutionized VUV, soft X-ray, and hard X-ray science. The second (present) generation of storage rings, e.g. the NSLS VUV and XRAY rings and Aladdin (Wisconsin), have sustained the revolution by providing higher stored currents and up to a factor of ten smaller electron beam sizes than the first generation sources. This has made possible a large number of experiments that could not performed using first generation sources. In addition, the NSLS XRAY ring design optimizes the performance of wigglers (high field periodic magnetic insertion devices). The third generation storage rings, e.g. ALS (Berkeley) and APS (Argonne), are being designed to optimize the performance of undulators (low field periodic magnetic insertion devices). These extremely high brightness sources will further revolutionize x-ray science by providing diffraction-limited x-ray beams. The output of undulators and wigglers is distinct from that of bending magnets in magnitude, spectral shape, and in spatial and angular size. Using published equations, we have developed computer programs to calculate the flux, central intensity, and brightness output bending magnets and selected wigglers and undulators of the NSLS VUV and XRAY rings, the Advanced Light Source (ALS), and the Advanced Photon Source (APS). Following is a summary of the equations used, the graphs and data produced, and the computer codes written. These codes, written in the C programming language, can be used to calculate the flux, central intensity, and brightness curves for bending magnets and insertion devices on any storage ring

Source brightness fluctuation correction of solar absorption fourier transform mid infrared spectra

Directory of Open Access Journals (Sweden)

T. Ridder

2011-06-01

Full Text Available The precision and accuracy of trace gas observations using solar absorption Fourier Transform infrared spectrometry depend on the stability of the light source. Fluctuations in the source brightness, however, cannot always be avoided. Current correction schemes, which calculate a corrected interferogram as the ratio of the raw DC interferogram and a smoothed DC interferogram, are applicable only to near infrared measurements. Spectra in the mid infrared spectral region below 2000 cm⁻¹ are generally considered uncorrectable, if they are measured with a MCT detector. Such measurements introduce an unknown offset to MCT interferograms, which prevents the established source brightness fluctuation correction. This problem can be overcome by a determination of the offset using the modulation efficiency of the instrument. With known modulation efficiency the offset can be calculated, and the source brightness correction can be performed on the basis of offset-corrected interferograms. We present a source brightness fluctuation correction method which performs the smoothing of the raw DC interferogram in the interferogram domain by an application of a running mean instead of high-pass filtering the corresponding spectrum after Fourier transformation of the raw DC interferogram. This smoothing can be performed with the onboard software of commercial instruments. The improvement of MCT spectra and subsequent ozone profile and total column retrievals is demonstrated. Application to InSb interferograms in the near infrared spectral region proves the equivalence with the established correction scheme.

Brightness enhancement of plasma ion source by utilizing anode spot for nano applications

International Nuclear Information System (INIS)

Park, Yeong-Shin; Lee, Yuna; Chung, Kyoung-Jae; Hwang, Y. S.; Kim, Yoon-Jae; Park, Man-Jin; Moon, Dae Won

2012-01-01

Anode spots are known as additional discharges on positively biased electrode immersed in plasmas. The anode spot plasma ion source (ASPIS) has been investigated as a high brightness ion source for nano applications such as focused ion beam (FIB) and nano medium energy ion scattering (nano-MEIS). The generation of anode spot is found to enhance brightness of ion beam since the anode spot increases plasma density near the extraction aperture. Brightness of the ASPIS has been estimated from measurement of emittance for total ion beam extracted through sub-mm aperture. The ASPIS is installed to the FIB system. Currents and diameters of the focused beams with/without anode spot are measured and compared. As the anode spot is turned on, the enhancement of beam current is observed at fixed diameter of the focused ion beam. Consequently, the brightness of the focused ion beam is enhanced as well. For argon ion beam, the maximum normalized brightness of 12 300 A/m 2 SrV is acquired. The ASPIS is applied to nano-MEIS as well. The ASPIS is found to increase the beam current density and the power efficiency of the ion source for nano-MEIS. From the present study, it is shown that the ASPIS can enhance the performance of devices for nano applications.

Contribution of field effects to the achievement of higher brightness ion sources

International Nuclear Information System (INIS)

Sudraud, P.; Walle, J. van de; Colliex, C.; Castaing, R.

1978-01-01

The use of field effects for the delivery of high brightness ion beams is considered. Two solutions have been experimentally investigated, which are intended to increase the supply function in a field ion microscope: a liquid fed field ionization source and a field desorption source. Their performances and characteristics have been compared and they suggest two different regimes of emission. The field desorption source seems however more likely to produce reliable results. Brightnesses on the source side of the order of 10 8 to 10 9 A/cm 2 sr are expected but much care must be devoted to the design of the electrostatic transfer optics of the gun to take full benefit of the intrinsic properties of such large solid angle emitters. (Auth.)

Bright focused ion beam sources based on laser-cooled atoms

Science.gov (United States)

McClelland, J. J.; Steele, A. V.; Knuffman, B.; Twedt, K. A.; Schwarzkopf, A.; Wilson, T. M.

2016-01-01

Nanoscale focused ion beams (FIBs) represent one of the most useful tools in nanotechnology, enabling nanofabrication via milling and gas-assisted deposition, microscopy and microanalysis, and selective, spatially resolved doping of materials. Recently, a new type of FIB source has emerged, which uses ionization of laser cooled neutral atoms to produce the ion beam. The extremely cold temperatures attainable with laser cooling (in the range of 100 μK or below) result in a beam of ions with a very small transverse velocity distribution. This corresponds to a source with extremely high brightness that rivals or may even exceed the brightness of the industry standard Ga+ liquid metal ion source. In this review we discuss the context of ion beam technology in which these new ion sources can play a role, their principles of operation, and some examples of recent demonstrations. The field is relatively new, so only a few applications have been demonstrated, most notably low energy ion microscopy with Li ions. Nevertheless, a number of promising new approaches have been proposed and/or demonstrated, suggesting that a rapid evolution of this type of source is likely in the near future. PMID:27239245

Bright focused ion beam sources based on laser-cooled atoms

Energy Technology Data Exchange (ETDEWEB)

McClelland, J. J.; Wilson, T. M. [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Steele, A. V.; Knuffman, B.; Schwarzkopf, A. [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); zeroK NanoTech, Gaithersburg, Maryland 20878 (United States); Twedt, K. A. [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Maryland Nanocenter, University of Maryland, College Park, Maryland 20742 (United States)

2016-03-15

Nanoscale focused ion beams (FIBs) represent one of the most useful tools in nanotechnology, enabling nanofabrication via milling and gas-assisted deposition, microscopy and microanalysis, and selective, spatially resolved doping of materials. Recently, a new type of FIB source has emerged, which uses ionization of laser cooled neutral atoms to produce the ion beam. The extremely cold temperatures attainable with laser cooling (in the range of 100 μK or below) result in a beam of ions with a very small transverse velocity distribution. This corresponds to a source with extremely high brightness that rivals or may even exceed the brightness of the industry standard Ga{sup +} liquid metal ion source. In this review, we discuss the context of ion beam technology in which these new ion sources can play a role, their principles of operation, and some examples of recent demonstrations. The field is relatively new, so only a few applications have been demonstrated, most notably low energy ion microscopy with Li ions. Nevertheless, a number of promising new approaches have been proposed and/or demonstrated, suggesting that a rapid evolution of this type of source is likely in the near future.

A SOUTHERN SKY AND GALACTIC PLANE SURVEY FOR BRIGHT KUIPER BELT OBJECTS

International Nuclear Information System (INIS)

Sheppard, Scott S.; Udalski, Andrzej; Kubiak, Marcin; Pietrzynski, Grzegorz; Poleski, Radoslaw; Soszynski, Igor; Szymanski, Michal K.; Ulaczyk, Krzysztof; Trujillo, Chadwick

2011-01-01

About 2500 deg 2 of sky south of declination -25 0 and/or near the Galactic Plane were surveyed for bright outer solar system objects. This survey is one of the first large-scale southern sky and Galactic Plane surveys to detect dwarf planets and other bright Kuiper Belt Objects in the trans-Neptunian region. The survey was able to obtain a limiting R-band magnitude of 21.6. In all, 18 outer solar system objects were detected, including Pluto which was detected near the Galactic center using optimal image subtraction techniques to remove the high stellar density background. Fourteen of the detections were previously unknown trans-Neptunian objects, demonstrating that the southern sky had not been well searched to date for bright outer solar system objects. Assuming moderate albedos, several of the new discoveries from this survey could be in hydrostatic equilibrium and thus could be considered dwarf planets. Combining this survey with previous surveys from the northern hemisphere suggests that the Kuiper Belt is nearly complete to around 21st magnitude in the R band. All the main dynamical classes in the Kuiper Belt are occupied by at least one dwarf-planet-sized object. The 3:2 Neptune resonance, which is the innermost well-populated Neptune resonance, has several large objects while the main outer Neptune resonances such as the 5:3, 7:4, 2:1, and 5:2 do not appear to have any large objects. This indicates that the outer resonances are either significantly depleted in objects relative to the 3:2 resonance or have a significantly different assortment of objects than the 3:2 resonance. For the largest objects (H < 4.5 mag), the scattered disk population appears to have a few times more objects than the main Kuiper Belt (MKB) population, while the Sedna population could be several times more than that of the MKB.

A high brightness source for nano-probe secondary ion mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Smith, N.S. [Oregon Physics LLC, 2704 SE 39th Loop, Suite 109, Hillsboro, OR 97123 (United States)], E-mail: n.smith@oregon-physics.com; Tesch, P.P.; Martin, N.P.; Kinion, D.E. [Oregon Physics LLC, 2704 SE 39th Loop, Suite 109, Hillsboro, OR 97123 (United States)

2008-12-15

The two most prevalent ion source technologies in the field of surface analysis and surface machining are the Duoplasmatron and the liquid metal ion source (LMIS). There have been many efforts in this area of research to develop an alternative source [; N.S. Smith, W.P. Skoczylas, S.M. Kellogg, D.E. Kinion, P.P. Tesch, O. Sutherland, A. Aanesland, R.W. Boswell, J. Vac. Sci. Technol. B 24 (6) (2006) 2902-2906] with the brightness of a LMIS and yet the ability to produce secondary ion yield enhancing species such as oxygen. However, to date a viable alternative has not been realized. The high brightness and small virtual source size of the LMIS are advantageous for forming high resolution probes but a significant disadvantage when beam currents in excess of 100 nA are required, due to the effects of spherical aberration from the optical column. At these higher currents a source with a high angular intensity is optimal and in fact the relatively moderate brightness of today's plasma ion sources prevail in this operating regime. Both the LMIS and Duoplasmatron suffer from a large axial energy spread resulting in further limitations when forming focused beams at the chromatic limit where the figure-of-merit is inversely proportional to the square of the energy spread. Also, both of these ion sources operate with a very limited range of ion species. This article reviews some of the latest developments and some future potential in this area of instrument development. Here we present an approach to source development that could lead to oxygen ion beam SIMS imaging with 10 nm resolution, using a 'broad area' RF gas phase ion source.

Brightness enhancement of plasma ion source by utilizing anode spot for nano applications

Energy Technology Data Exchange (ETDEWEB)

Park, Yeong-Shin; Lee, Yuna; Chung, Kyoung-Jae; Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, Yoon-Jae [Samsung Electronics Co. Ltd., Gyeonggi 445-701 (Korea, Republic of); Park, Man-Jin [Research Institute of Nano Manufacturing System, Seoul National University of Science and Technology, Seoul 139-743 (Korea, Republic of); Moon, Dae Won [Nanobio Fusion Research Center, Korea Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of)

2012-02-15

Anode spots are known as additional discharges on positively biased electrode immersed in plasmas. The anode spot plasma ion source (ASPIS) has been investigated as a high brightness ion source for nano applications such as focused ion beam (FIB) and nano medium energy ion scattering (nano-MEIS). The generation of anode spot is found to enhance brightness of ion beam since the anode spot increases plasma density near the extraction aperture. Brightness of the ASPIS has been estimated from measurement of emittance for total ion beam extracted through sub-mm aperture. The ASPIS is installed to the FIB system. Currents and diameters of the focused beams with/without anode spot are measured and compared. As the anode spot is turned on, the enhancement of beam current is observed at fixed diameter of the focused ion beam. Consequently, the brightness of the focused ion beam is enhanced as well. For argon ion beam, the maximum normalized brightness of 12 300 A/m{sup 2} SrV is acquired. The ASPIS is applied to nano-MEIS as well. The ASPIS is found to increase the beam current density and the power efficiency of the ion source for nano-MEIS. From the present study, it is shown that the ASPIS can enhance the performance of devices for nano applications.

Intrinsic brightness temperatures of blazar jets at 15 GHz

Directory of Open Access Journals (Sweden)

Hovatta Talvikki

2013-12-01

Full Text Available We have developed a new Bayesian Markov Chain Monte Carlo method to deconvolve light curves of blazars into individual flares, including proper estimation of the fit errors. We use the method to fit 15GHzlight curves obtained within the OVRO 40-m blazar monitoring program where a large number of AGN have been monitored since 2008 in support of the Fermi Gamma-Ray Space Telescope mission. The time scales obtained from the fitted models are used to calculate the variability brightness temperature of the sources. Additionally, we have calculated brightness temperatures of a sample of these objects using Very Long Baseline Array data from the MOJAVE survey. Combining these two data sets enables us to study the intrinsic brightness temperature distribution in these blazars at 15 GHz. Our preliminary results indicate that the mean intrinsic brightness temperature in a sample of 14 sources is near the equipartition brightness temperature of ~ 1011K.

The Brightest of Reionizing Galaxies Survey: Constraints on the Bright End of the z ~ 8 Luminosity Function

Science.gov (United States)

Bradley, L. D.; Trenti, M.; Oesch, P. A.; Stiavelli, M.; Treu, T.; Bouwens, R. J.; Shull, J. M.; Holwerda, B. W.; Pirzkal, N.

2012-12-01

We report the discovery of 33 Lyman-break galaxy candidates at z ~ 8 detected in Hubble Space Telescope Wide Field Camera 3 (WFC3) imaging as part of the Brightest of Reionizing Galaxies (BoRG) pure-parallel survey. The ongoing BoRG survey currently has the largest area (274 arcmin2) with Y 098 (or Y 105), J 125, and H 160 band coverage needed to search for z ~ 8 galaxies, about three times the current CANDELS area, and slightly larger than what will be the final CANDELS wide component with Y 105 data (required to select z ~ 8 sources). Our sample of 33 relatively bright Y 098-dropout galaxies have J 125-band magnitudes between 25.5 and 27.4 mag. This is the largest sample of bright (J 125 universe. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy under NASA contract NAS5-26555. These observations are associated with programs 11519, 11520, 11524, 11528, 11530, 11533, 11534, 11541, 11700, 11702, 12024, 12025, and 12572.

Mass Functions of the Active Black Holes in Distant Quasars from the Large Bright Quasar Survey, the Bright Quasar Survey, and the Color-Selected Sample of the SDSS Fall Equatorial Stripe

DEFF Research Database (Denmark)

Vestergaard, Marianne; Osmer, Patrick S.

2009-01-01

We present mass functions of distant actively accreting supermassive black holes residing in luminous quasars discovered in the Large Bright Quasar Survey, the Bright Quasar Survey, and the Fall Equatorial Stripe of the Sloan Digital Sky Survey (SDSS). The quasars cover a wide range of redshifts (0...... functions at similar redshifts based on the SDSS Data Release 3 quasar catalog presented by Vestergaard et al. We see clear evidence of cosmic downsizing in the comoving space density distribution of active black holes in the LBQS sample alone. In forthcoming papers, further analysis, comparison......, and discussion of these mass functions will be made with other existing black hole mass functions, notably that based on the SDSS DR3 quasar catalog. We present the relationships used to estimate the black hole mass based on the MgII emission line; the relations are calibrated to the Hbeta and CIV relations...

A 5-GHz survey of bright southern elliptical and SO galaxies

International Nuclear Information System (INIS)

Disney, M.J.; Wall, J.V.

1977-01-01

The Parkes 64-m telescope has been used in a 5.0 GHz survey of 181 Southern E and SO galaxies from the Reference catalogue of bright galaxies. Of the 39 detections above the nominal limit of 12 mJy, 15 are new, several have radio spectra indicating membership in the active class, and two have shown intensity variations at centimetre wavelengths. The results of this survey combined with results from earlier surveys of lower sensitivity suggest that only about 40 per cent of the E/SO galaxies in the Reference catalogue have Ssub(5GHz)>1 mJy. (author)

High Brightness Neutron Source for Radiography. Final report

International Nuclear Information System (INIS)

Cremer, J.T.; Piestrup, Melvin A.; Gary, Charles K.; Harris, Jack L.; Williams, David J.; Jones, Glenn E.; Vainionpaa, J.H.; Fuller, Michael J.; Rothbart, George H.; Kwan, J.W.; Ludewigt, B.A.; Gough, R.A.; Reijonen, Jani; Leung, Ka-Ngo

2008-01-01

This research and development program was designed to improve nondestructive evaluation of large mechanical objects by providing both fast and thermal neutron sources for radiography. Neutron radiography permits inspection inside objects that x-rays cannot penetrate and permits imaging of corrosion and cracks in low-density materials. Discovering of fatigue cracks and corrosion in piping without the necessity of insulation removal is possible. Neutron radiography sources can provide for the nondestructive testing interests of commercial and military aircraft, public utilities and petrochemical organizations. Three neutron prototype neutron generators were designed and fabricated based on original research done at the Lawrence Berkeley National Laboratory (LBNL). The research and development of these generators was successfully continued by LBNL and Adelphi Technology Inc. under this STTR. The original design goals of high neutron yield and generator robustness have been achieved, using new technology developed under this grant. In one prototype generator, the fast neutron yield and brightness was roughly 10 times larger than previously marketed neutron generators using the same deuterium-deuterium reaction. In another generator, we integrate a moderator with a fast neutron source, resulting in a high brightness thermal neutron generator. The moderator acts as both conventional moderator and mechanical and electrical support structure for the generator and effectively mimics a nuclear reactor. In addition to the new prototype generators, an entirely new plasma ion source for neutron production was developed. First developed by LBNL, this source uses a spiral antenna to more efficiently couple the RF radiation into the plasma, reducing the required gas pressure so that the generator head can be completely sealed, permitting the possible use of tritium gas. This also permits the generator to use the deuterium-tritium reaction to produce 14-MeV neutrons with increases

THE BRIGHTEST OF REIONIZING GALAXIES SURVEY: CONSTRAINTS ON THE BRIGHT END OF THE z {approx} 8 LUMINOSITY FUNCTION

Energy Technology Data Exchange (ETDEWEB)

Bradley, L. D.; Stiavelli, M.; Pirzkal, N. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Trenti, M. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Oesch, P. A. [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Treu, T. [Department of Physics, University of California, Santa Barbara, CA 93106-9530 (United States); Bouwens, R. J. [Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands); Shull, J. M. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Holwerda, B. W. [European Space Agency (ESTEC), Keplerlaan 1, NL-2200 AG, Noordwijk (Netherlands)

2012-12-01

We report the discovery of 33 Lyman-break galaxy candidates at z {approx} 8 detected in Hubble Space Telescope Wide Field Camera 3 (WFC3) imaging as part of the Brightest of Reionizing Galaxies (BoRG) pure-parallel survey. The ongoing BoRG survey currently has the largest area (274 arcmin{sup 2}) with Y {sub 098} (or Y {sub 105}), J {sub 125}, and H {sub 160} band coverage needed to search for z {approx} 8 galaxies, about three times the current CANDELS area, and slightly larger than what will be the final CANDELS wide component with Y {sub 105} data (required to select z {approx} 8 sources). Our sample of 33 relatively bright Y {sub 098}-dropout galaxies have J {sub 125}-band magnitudes between 25.5 and 27.4 mag. This is the largest sample of bright (J {sub 125} {approx}< 27.4) z {approx} 8 galaxy candidates presented to date. Combining our data set with the Hubble Ultra-Deep Field data set, we constrain the rest-frame ultraviolet galaxy luminosity function at z {approx} 8 over the widest dynamic range currently available. The combined data sets are well fitted by a Schechter function, i.e., {phi} (L) = {phi}{sub *} (L/L{sub *}){sup {alpha}} e{sup -(}L{sup /L{sub *})}, without evidence for an excess of sources at the bright end. At 68% confidence, for h = 0.7 we derive {phi}{sub *} = (4.3{sup +3.5} {sub -2.1}) Multiplication-Sign 10{sup -4} Mpc{sup -3}, M {sub *} = -20.26{sup +0.29} {sub -0.34}, and a very steep faint-end slope {alpha} = -1.98{sup +0.23} {sub -0.22}. While the best-fit parameters still have a strong degeneracy, especially between {phi}{sub *} and M {sub *}, our improved coverage at the bright end has reduced the uncertainty of the faint-end power-law slope at z {approx} 8 compared to the best previous determination at {+-}0.4. With a future expansion of the BoRG survey, combined with planned ultradeep WFC3/IR observations, it will be possible to further reduce this uncertainty and clearly demonstrate the steepening of the faint-end slope compared

Very-High-Brightness Picosecond Electron Source

International Nuclear Information System (INIS)

Bluem, H.

2003-01-01

Bright, RF photocathode electron guns are the source of choice for most high-performance research accelerator applications. Some of these applications are pushing the performance boundaries of the present state-of-the-art guns. Advanced Energy Systems is developing a novel photocathode RF gun that shows excellent promise for extending gun performance. Initial gun simulations with only a short booster accelerator easily break the benchmark emittance of one micron for 1 nC of bunch charge. The pulse length in these simulations is less than 2 ps. It is expected that with more detailed optimization studies, the performance can be further improved. The performance details of the gun will be presented. In addition, we will discuss the present design concept along with the status of the project

Electron Source Brightness and Illumination Semi-Angle Distribution Measurement in a Transmission Electron Microscope.

Science.gov (United States)

Börrnert, Felix; Renner, Julian; Kaiser, Ute

2018-05-21

The electron source brightness is an important parameter in an electron microscope. Reliable and easy brightness measurement routes are not easily found. A determination method for the illumination semi-angle distribution in transmission electron microscopy is even less well documented. Herein, we report a simple measurement route for both entities and demonstrate it on a state-of-the-art instrument. The reduced axial brightness of the FEI X-FEG with a monochromator was determined to be larger than 108 A/(m2 sr V).

Bright nanoscale source of deterministic entangled photon pairs violating Bell's inequality

NARCIS (Netherlands)

Jöns, K.D.; Schweickert, L.S.; Versteegh, M.A.M.; Dalacu, Dan; Poole, Philip J.; Gulinatti, Angelo; Giudice, Andrea; Zwiller, V.G.; Reimer, M.E.

2017-01-01

Global, secure quantum channels will require efficient distribution of entangled photons. Long distance, low-loss interconnects can only be realized using photons as quantum information carriers. However, a quantum light source combining both high qubit fidelity and on-demand bright emission has

Bright and durable field emission source derived from refractory taylor cones

Science.gov (United States)

Hirsch, Gregory

2016-12-20

A method of producing field emitters having improved brightness and durability relying on the creation of a liquid Taylor cone from electrically conductive materials having high melting points. The method calls for melting the end of a wire substrate with a focused laser beam, while imposing a high positive potential on the material. The resulting molten Taylor cone is subsequently rapidly quenched by cessation of the laser power. Rapid quenching is facilitated in large part by radiative cooling, resulting in structures having characteristics closely matching that of the original liquid Taylor cone. Frozen Taylor cones thus obtained yield desirable tip end forms for field emission sources in electron beam applications. Regeneration of the frozen Taylor cones in-situ is readily accomplished by repeating the initial formation procedures. The high temperature liquid Taylor cones can also be employed as bright ion sources with chemical elements previously considered impractical to implement.

Considerations for high-brightness electron sources

International Nuclear Information System (INIS)

Jameson, R.A.

1990-01-01

Particle accelerators are now used in many areas of physics research and in industrial and medical applications. New uses are being studied to address major societal needs in energy production, materials research, generation of intense beams of radiation at optical and suboptical wavelengths, treatment of various kinds of waste, and so on. Many of these modern applications require a high intensity beam at the desired energy, along with a very good beam quality in terms of the beam confinement, aiming, or focusing. Considerations for ion and electron accelerators are often different, but there are also many commonalties, and in fact, techniques derived for one should perhaps more often be considered for the other as well. We discuss some aspects of high-brightness electron sources here from that point of view. 6 refs

Three Millisecond Pulsars in Fermi LAT Unassociated Bright Sources

Science.gov (United States)

Ransom, S. M.; Ray, P. S.; Camilo, F.; Roberts, M. S. E.; Celik, O.; Wolff, M. T.; Cheung, C. C.; Kerr, M.; Pennucci, T.; DeCesar, M. E.;

High brightness ion source

International Nuclear Information System (INIS)

Dreyfus, R.W.; Hodgson, R.T.

1975-01-01

A high brightness ion beam is obtainable by using lasers to excite atoms or molecules from the ground state to an ionized state in increments, rather than in one step. The spectroscopic resonances of the atom or molecule are used so that relatively long wavelength, low power lasers can be used to obtain such ion beam

Plans to increase source brightness of NSLS x-ray ring

International Nuclear Information System (INIS)

Safranek, J.; Krinsky, S.

1993-01-01

We discuss plans to increase the NSLS X-Ray ring source brightness by an order of magnitude. Proposed improvements include doubling current from 250 mA to 500 mA, reducing vertical emittance by a factor of 6 and reducing insertion device gaps and periods by up to a factor of two. Experimental results are reported which indicate we have succeeded in reducing the vertical emittance below 2 Angstrom

Studies on a laser driven photoemissive high-brightness electron source and novel photocathodes

International Nuclear Information System (INIS)

Geng Rongli; Song Jinhu; Yu Jin

1997-01-01

A laser driven photoemissive high-brightness electron source at Beijing University is reported. Through a DC accelerating gap of 100 kV voltage, the device is capable of delivering high-brightness electron beam of 35-100 ps pulse duration when irradiated with a mode-locked YAG laser. The geometry of the gun is optimized with the aid of simulation codes EGUN and POISSON. The results of experimental studies on ion implanted photocathode and cesium telluride photocathode are given. The proposed laser driven superconducting RF gun is also discussed

Providing Bright-Hard X-ray Beams from a Lower Energy Light Source

Science.gov (United States)

Robin, David

2002-04-01

At the Advanced Light Source (ALS) there had been an increasing demand for more high brightness harder X-ray sources in the 7 to 40 KeV range. In response to that demand, the ALS storage ring was modified in August 2001. Three 1.3 Tesla normal conducting bending magnets were removed and replaced with three 5 Tesla superconducting magnets (Superbends). The radiation produced by these Superbends is an order of magnitude higher in photon brightness and flux at 12 keV than the 1.3 Tesla bends, making them excellent sources of harder x-rays for protein crystallography and other harder x-ray applications. At the same time the Superbends do not compromise the performance of the facility in the UV and Soft X-ray regions of the spectrum. The Superbends will eventually feed 12 new x-ray beam lines greatly enhancing the facility's capacity in the hard x-ray region. The Superbend project is the biggest upgrade to the ALS storage ring since the ring was commissioned in 1993. In this paper we present, a history of the project, details of the magnet, installation, commissioning, and resulting performance of the ALS with Superbends.

H{sub 2}O Megamasers toward Radio-bright Seyfert 2 Nuclei

Energy Technology Data Exchange (ETDEWEB)

Zhang, J. S.; Liu, Z. W. [Center for Astrophysics, Guangzhou University, Guangzhou, 510006 (China); Henkel, C. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Wang, J. Z. [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Coldwell, G. V., E-mail: jszhang@gzhu.edu.cn [FCEFyN-UNSJ-CONICET, San Juan (Argentina)

2017-02-20

Using the Effelsberg-100 m telescope, we perform a successful pilot survey on H{sub 2}O maser emission toward a small sample of radio-bright Seyfert 2 galaxies with a redshift larger than 0.04. The targets were selected from a large Seyfert 2 sample derived from the spectroscopic Sloan Digital Sky Survey Data Release 7 (SDSS-DR7). One source, SDSS J102802.9+104630.4 ( z ∼ 0.0448), was detected four times during our observations, with a typical maser flux density of ∼30 mJy and a corresponding (very large) luminosity of ∼1135 L {sub ⊙}. The successful detection of this radio-bright Seyfert 2 and an additional tentative detection support our previous statistical results that H{sub 2}O megamasers tend to arise from Seyfert 2 galaxies with large radio luminosity. The finding provides further motivation for an upcoming larger H{sub 2}O megamaser survey toward Seyfert 2s with particularly radio-bright nuclei with the basic goal to improve our understanding of the nuclear environment of active megamaser host galaxies.

High Brightness, Laser-Driven X-ray Source for Nanoscale Metrology and Femtosecond Dynamics

Energy Technology Data Exchange (ETDEWEB)

Siders, C W; Crane, J K; Semenov, V; Betts, S; Kozioziemski, B; Wharton, K; Wilks, S; Barbee, T; Stuart, B; Kim, D E; An, J; Barty, C

2007-02-26

This project developed and demonstrated a new, bright, ultrafast x-ray source based upon laser-driven K-alpha generation, which can produce an x-ray flux 10 to 100 times greater than current microfocus x-ray tubes. The short-pulse (sub-picosecond) duration of this x-ray source also makes it ideal for observing time-resolved dynamics of atomic motion in solids and thin films.

On the Nature of Bright Infrared Sources in the Small Magellanic Cloud: Interpreting MSX through the Lens of Spitzer

Science.gov (United States)

Kraemer, Kathleen E.; Sloan, G. C.

2015-01-01

We compare infrared observations of the Small Magellanic Cloud (SMC) by the Midcourse Space Experiment (MSX) and the Spitzer Space Telescope to better understand what components of a metal-poor galaxy dominate radiative processes in the infrared. The SMC, at a distance of ~60 kpc and with a metallicity of ~0.1-0.2 solar, can serve as a nearby proxy for metal-poor galaxies at high redshift. The MSX Point Source Catalog contains 243 objects in the SMC that were detected at 8.3 microns, the most sensitive MSX band. Multi-epoch, multi-band mapping with Spitzer, supplemented with observations from the Two-Micron All-Sky Survey (2MASS) and the Wide-field Infrared Survey Explorer (WISE), provides variability information, and, together with spectra from Spitzer for ~15% of the sample, enables us to determine what these luminous sources are. How many remain simple point sources? What fraction break up into multiple stars? Which are star forming regions, with both bright diffuse emission and point sources? How do evolved stars and stellar remnants contribute at these wavelengths? What role do young stellar objects and HII regions play? Answering these questions sets the stage for understanding what we will see with the James Webb Space Telescope (JWST).

The emittance and brightness characteristics of negative ion sources suitable for MeV ion implantation

International Nuclear Information System (INIS)

Alton, G.D.

1987-01-01

This paper provides the description and beam properties of ion sources suitable for use with ion implantation devices. Particular emphasis is placed on the emittance and brightness properties of state-of-the-art, high intensity, negative ion sources based on the cesium ion sputter principle

H2O Megamasers toward Radio-bright Seyfert 2 Nuclei

Science.gov (United States)

Zhang, J. S.; Liu, Z. W.; Henkel, C.; Wang, J. Z.; Coldwell, G. V.

2017-02-01

Using the Effelsberg-100 m telescope, we perform a successful pilot survey on H2O maser emission toward a small sample of radio-bright Seyfert 2 galaxies with a redshift larger than 0.04. The targets were selected from a large Seyfert 2 sample derived from the spectroscopic Sloan Digital Sky Survey Data Release 7 (SDSS-DR7). One source, SDSS J102802.9+104630.4 (z ˜ 0.0448), was detected four times during our observations, with a typical maser flux density of ˜30 mJy and a corresponding (very large) luminosity of ˜1135 L ⊙. The successful detection of this radio-bright Seyfert 2 and an additional tentative detection support our previous statistical results that H2O megamasers tend to arise from Seyfert 2 galaxies with large radio luminosity. The finding provides further motivation for an upcoming larger H2O megamaser survey toward Seyfert 2s with particularly radio-bright nuclei with the basic goal to improve our understanding of the nuclear environment of active megamaser host galaxies. Based on observations with the 100 m telescope of the MPIfR (Max-Planck-Institut für Radioastronomie) at Effelsberg.

Illuminating Low Surface Brightness Galaxies with the Hyper Suprime-Cam Survey

Science.gov (United States)

Greco, Johnny P.; Greene, Jenny E.; Strauss, Michael A.; Macarthur, Lauren A.; Flowers, Xzavier; Goulding, Andy D.; Huang, Song; Kim, Ji Hoon; Komiyama, Yutaka; Leauthaud, Alexie; Leisman, Lukas; Lupton, Robert H.; Sifón, Cristóbal; Wang, Shiang-Yu

2018-04-01

We present a catalog of extended low surface brightness galaxies (LSBGs) identified in the Wide layer of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). Using the first ∼200 deg2 of the survey, we have uncovered 781 LSBGs, spanning red (g ‑ i ≥ 0.64) and blue (g ‑ i r eff = 2.″5–14″), our sample is likely dominated by low-redshift objects. We define LSBGs to have mean surface brightnesses {\\bar{μ }}eff}(g)> 24.3 mag arcsec‑2, which allows nucleated galaxies into our sample. As a result, the central surface brightness distribution spans a wide range of μ 0(g) = 18–27.4 mag arcsec‑2, with 50% and 95% of galaxies fainter than 24.3 and 22 mag arcsec‑2, respectively. Furthermore, the surface brightness distribution is a strong function of color, with the red distribution being much broader and generally fainter than that of the blue LSBGs, and this trend shows a clear correlation with galaxy morphology. Red LSBGs typically have smooth light profiles that are well characterized by single-component Sérsic functions. In contrast, blue LSBGs tend to have irregular morphologies and show evidence for ongoing star formation. We cross-match our sample with existing optical, H I, and ultraviolet catalogs to gain insight into the physical nature of the LSBGs. We find that our sample is diverse, ranging from dwarf spheroidals and ultradiffuse galaxies in nearby groups to gas-rich irregulars to giant LSB spirals, demonstrating the potential of the HSC-SSP to provide a truly unprecedented view of the LSBG population.

High-brightness electron guns for linac-based light sources

International Nuclear Information System (INIS)

Lewellen, J.W.

2004-01-01

Most proposed linac-based light sources, such as single-pass free-electron lasers and energy-recovery-linacs, require very high-brightness electron beams in order to achieve their design performance. These beam requirements must be achieved not on an occasional basis, but rather must be met by every bunch produced by the source over extended periods of time. It is widely assumed that the beam source will be a photocathode electron gun; the selection of accelerator technique (e.g., dc or rf) for the gun is more dependent on the application.The current state of the art of electron beam production is adequate but not ideal for the first generation of linac-based light sources, such as the Linac Coherent Light Source (LCLS) x-ray free-electron laser (X-FEL). For the next generation of linac-based light sources, an order of magnitude reduction in the transverse electron beam emittance is required to significantly reduce the cost of the facility. This is beyond the present state of the art, given the other beam properties that must be maintained. The requirements for current and future linac-based light source beam sources are presented here, along with a review of the present state of the art. A discussion of potential paths towards meeting future needs is presented at the conclusion.

Heat sources for bright-rimmed molecular clouds: CO observations of NGC 7822

International Nuclear Information System (INIS)

Elmegreen, B.G.; Dickinson, D.F.; Lada, C.J.

1978-01-01

Observations of the 2.6 mm carbon monoxide line in the bright rim NGC 7822 reveal that the peak excitation and column density of the molecule lie in a ridge ahead of the ionization front. Several possibilities for the excitation of this ridge are discussed. Cosmic rays are shown to provide an excellent heat source for Bok globules, but they can account for only approx.20% of the required heating in NGC 7822. Direct shock or compressional heating of the gas could be adequate only if the pressure inside the cloud is much larger than the thermal pressure. If, in fact, this internal pressure is determined by the source of line broadening (e.g., magnetic fields or turbulence), then shock or compressional heating could be important, and pressure equilibrium may exist between the neutral cloud and the bright rim. Heating by warm grains or by the photoelectric effect is also considered, but such mechanisms are probably not important if the only source of radiation is external to the cloud. This is primarily a result of the low cloud density (approx.10 3 cm -3 ) inferred from our observations. The extent to which unknown embedded stars may provide the required gaseous heating cannot be estimated from our observations of NGC 7822.An interesting and new heat source is suggested which may have important applications to bright-rimmed clouds or to any other predominantly neutral clouds that may have undergone some recent compression. We suggest that the heat input to neutral gas due to the relaxation of internal magnetic fields will be greatly enhanced during cloud compression (with or without a shock). We show that the power input to the gas will increase more with increasing density than will the cooling rate. As a result, cloud compression can lead to an increase in the gas temperature for a period lasting several million years, which is the decay time of the compressed field. The observed ridge in NGC 7822 may be due to stimulated release of internal magnetic energy

GYRO-ORBIT SIZE, BRIGHTNESS TEMPERATURE LIMIT, AND IMPLAUSIBILITY OF COHERENT EMISSION BY BUNCHING IN SYNCHROTRON RADIO SOURCES

International Nuclear Information System (INIS)

Singal, Ashok K.

2012-01-01

We show that an upper limit on the maximum brightness temperature for a self-absorbed incoherent synchrotron radio source is obtained from the size of its gyro orbits, which in turn must lie well within the confines of the total source extent. These temperature limits are obtained without recourse to inverse Compton effects or the condition of equipartition of energy between magnetic fields and relativistic particles. For radio variables, the intra-day variability implies brightness temperatures ∼10 19 K in the comoving rest frame of the source. This, if interpreted purely due to an incoherent synchrotron emission, would imply gyroradii >10 28 cm, the size of the universe, while from the causality arguments the inferred maximum size of the source in such a case is ∼ 15 cm. Such high brightness temperatures are sometimes modeled in the literature as some coherent emission process where bunches of non-thermal particles are somehow formed that radiate in phase. We show that, unlike in the case of curvature radiation models proposed in pulsars, in the synchrotron radiation mechanism the oppositely charged particles would contribute together to the coherent phenomenon without the need to form separate bunches of the opposite charges. At the same time we show that bunches would disperse over dimensions larger than a wavelength in time shorter than the gyro orbital period (∼< 0.1 s). Therefore, a coherent emission by bunches cannot be a plausible explanation of the high brightness temperatures inferred in extragalactic radio sources showing variability over a few hours or longer.

Simple, compact, high brightness source for x-ray lithography and x-ray radiography

International Nuclear Information System (INIS)

Hawryluk, A.M.

1986-01-01

A simple, compact, high brightness x-ray source has recently been built. This source utilizes a commercially available, cylindrical geometry electron beam evaporator, which has been modified to enhance the thermal cooling to the anode. Cooling is accomplished by using standard, low-conductivity laboratory water, with an inlet pressure of less than 50 psi, and a flow rate of approx.0.3 gal/min. The anode is an inverted cone geometry for efficient cooling. The x-ray source has a measured sub-millimeter spot size (FWHM). The anode has been operated at 1 KW e-beam power (10 KV, 100 ma). Higher operating levels will be investigated. A variety of different x-ray lines can be obtained by the simple interchange of anodes of different materials. Typical anodes are made from easily machined metals, or materials which are vacuum deposited onto a copper anode. Typically, a few microns of material is sufficient to stop 10 KV electrons without significantly decreasing the thermal conductivity through the anode. The small size and high brightness of this source make it useful for step and repeat exposures over several square centimeter areas, especially in a research laboratory environment. For an aluminum anode, the estimated Al-K x-ray flux at 10 cms from the source is 70 μW/cm 2

THE HST/ACS COMA CLUSTER SURVEY. II. DATA DESCRIPTION AND SOURCE CATALOGS

International Nuclear Information System (INIS)

Hammer, Derek; Verdoes Kleijn, Gijs; Den Brok, Mark; Peletier, Reynier F.; Hoyos, Carlos; Balcells, Marc; Aguerri, Alfonso L.; Ferguson, Henry C.; Goudfrooij, Paul; Carter, David; Guzman, Rafael; Smith, Russell J.; Lucey, John R.; Graham, Alister W.; Trentham, Neil; Peng, Eric; Puzia, Thomas H.; Jogee, Shardha; Batcheldor, Dan; Bridges, Terry J.

2010-01-01

The Coma cluster, Abell 1656, was the target of an HST-ACS Treasury program designed for deep imaging in the F475W and F814W passbands. Although our survey was interrupted by the ACS instrument failure in early 2007, the partially completed survey still covers ∼50% of the core high-density region in Coma. Observations were performed for 25 fields that extend over a wide range of cluster-centric radii (∼1.75 Mpc or 1 0 ) with a total coverage area of 274 arcmin 2 . The majority of the fields are located near the core region of Coma (19/25 pointings) with six additional fields in the southwest region of the cluster. In this paper, we present reprocessed images and SEXTRACTOR source catalogs for our survey fields, including a detailed description of the methodology used for object detection and photometry, the subtraction of bright galaxies to measure faint underlying objects, and the use of simulations to assess the photometric accuracy and completeness of our catalogs. We also use simulations to perform aperture corrections for the SEXTRACTOR Kron magnitudes based only on the measured source flux and its half-light radius. We have performed photometry for ∼73,000 unique objects; approximately one-half of our detections are brighter than the 10σ point-source detection limit at F814W = 25.8 mag (AB). The slight majority of objects (60%) are unresolved or only marginally resolved by ACS. We estimate that Coma members are 5%-10% of all source detections, which consist of a large population of unresolved compact sources (primarily globular clusters but also ultra-compact dwarf galaxies) and a wide variety of extended galaxies from a cD galaxy to dwarf low surface brightness galaxies. The red sequence of Coma member galaxies has a color-magnitude relation with a constant slope and dispersion over 9 mag (-21 F814W < -13). The initial data release for the HST-ACS Coma Treasury program was made available to the public in 2008 August. The images and catalogs described

Source brightness and useful beam current of carbon nanotubes and other very small emitters

International Nuclear Information System (INIS)

Kruit, P.; Bezuijen, M.; Barth, J.E.

2006-01-01

The potential application of carbon nanotubes as electron sources in electron microscopes is analyzed. The resolution and probe current that can be obtained from a carbon nanotube emitter in a low-voltage scanning electron microscope are calculated and compared to the state of the art using Schottky electron sources. Many analytical equations for probe-size versus probe-current relations in different parameter regimes are obtained. It is shown that for most carbon nanotube emitters, the gun lens aberrations are larger than the emitters' virtual source size and thus restrict the microscope's performance. The result is that the advantages of the higher brightness of nanotube emitters are limited unless the angular emission current is increased over present day values or the gun lens aberrations are decreased. For some nanotubes with a closed cap, it is known that the emitted electron beam is coherent over the full emission cone. We argue that for such emitters the parameter ''brightness'' becomes meaningless. The influence of phase variations in the electron wave front emitted from such a nanotube emitter on the focusing of the electron beam is analyzed

Spatially single-mode source of bright squeezed vacuum

OpenAIRE

Pérez, A. M.; Iskhakov, T. Sh.; Sharapova, P.; Lemieux, S.; Tikhonova, O. V.; Chekhova, M. V.; Leuchs, G.

2014-01-01

Bright squeezed vacuum, a macroscopic nonclassical state of light, can be obtained at the output of a strongly pumped non-seeded traveling-wave optical parametric amplifier (OPA). By constructing the OPA of two consecutive crystals separated by a large distance we make the squeezed vacuum spatially single-mode without a significant decrease in the brightness or squeezing.

VizieR Online Data Catalog: FIR data of IR-bright dust-obscured galaxies (DOGs) (Toba+, 2017)

Science.gov (United States)

Toba, Y.; Nagao, T.; Wang, W.-H.; Matsuhara, H.; Akiyama, M.; Goto, T.; Koyama, Y.; Ohyama, Y.; Yamamura, I.

2017-11-01

We investigate the star-forming activity of a sample of infrared (IR)-bright dust-obscured galaxies (DOGs) that show an extreme red color in the optical and IR regime, (i-[22])AB>7.0. Combining an IR-bright DOG sample with the flux at 22μm>3.8mJy discovered by Toba & Nagao (2016ApJ...820...46T) with the IRAS faint source catalog version 2 and AKARI far-IR (FIR) all-sky survey bright source catalog version 2, we selected 109 DOGs with FIR data. For a subsample of seven IR-bright DOGs with spectroscopic redshifts (0.07DOGs and (2) the contribution of the active galactic nucleus to IR luminosity increases with IR luminosity. By comparing the stellar mass and SFR relation for our DOG sample and the literature, we found that most of the IR-bright DOGs lie significantly above the main sequence of star-forming galaxies at similar redshift, indicating that the majority of IRAS- or AKARI-detected IR-bright DOGs are starburst galaxies. (1 data file).

Variability Properties of Four Million Sources in the TESS Input Catalog Observed with the Kilodegree Extremely Little Telescope Survey

Science.gov (United States)

Oelkers, Ryan J.; Rodriguez, Joseph E.; Stassun, Keivan G.; Pepper, Joshua; Somers, Garrett; Kafka, Stella; Stevens, Daniel J.; Beatty, Thomas G.; Siverd, Robert J.; Lund, Michael B.; Kuhn, Rudolf B.; James, David; Gaudi, B. Scott

2018-01-01

The Kilodegree Extremely Little Telescope (KELT) has been surveying more than 70% of the celestial sphere for nearly a decade. While the primary science goal of the survey is the discovery of transiting, large-radii planets around bright host stars, the survey has collected more than 106 images, with a typical cadence between 10–30 minutes, for more than four million sources with apparent visual magnitudes in the approximate range 7TESS Input catalog and the AAVSO Variable Star Index to precipitate the follow-up and classification of each source. The catalog is maintained as a living database on the Filtergraph visualization portal at the URL https://filtergraph.com/kelt_vars.

Source Plane Reconstruction of the Bright Lensed Galaxy RCSGA 032727-132609

Science.gov (United States)

Sharon, Keren; Gladders, Michael D.; Rigby, Jane R.; Wuyts, Eva; Koester, Benjamin P.; Bayliss, Matthew B.; Barrientos, L. Felipe

2011-01-01

We present new HST/WFC3 imaging data of RCS2 032727-132609, a bright lensed galaxy at z=1.7 that is magnified and stretched by the lensing cluster RCS2 032727-132623. Using this new high-resolution imaging, we modify our previous lens model (which was based on ground-based data) to fully understand the lensing geometry, and use it to reconstruct the lensed galaxy in the source plane. This giant arc represents a unique opportunity to peer into 100-pc scale structures in a high redshift galaxy. This new source reconstruction will be crucial for a future analysis of the spatially-resolved rest-UV and rest-optical spectra of the brightest parts of the arc.

Bright X-ray source from a laser-driven micro-plasma-waveguide

CERN Document Server

Yi, Longqing

2016-01-01

Bright tunable x-ray sources have a number of applications in basic science, medicine and industry. The most powerful sources are synchrotrons, where relativistic electrons are circling in giant storage rings. In parallel, compact laser-plasma x-ray sources are being developed. Owing to the rapid progress in laser technology, very high-contrast femtosecond laser pulses of relativistic intensities become available. These pulses allow for interaction with micro-structured solid-density plasma without destroying the structure by parasitic pre-pulses. The high-contrast laser pulses as well as the manufacturing of materials at micro- and nano-scales open a new realm of possibilities for laser interaction with photonic materials at the relativistic intensities. Here we demonstrate, via numerical simulations, that when coupling with a readily available 1.8 Joule laser, a micro-plasma-waveguide (MPW) may serve as a novel compact x-ray source. Electrons are extracted from the walls by the laser field and form a dense ...

Using the Chandra Source-Finding Algorithm to Automatically Identify Solar X-ray Bright Points

Science.gov (United States)

Adams, Mitzi L.; Tennant, A.; Cirtain, J. M.

2009-01-01

This poster details a technique of bright point identification that is used to find sources in Chandra X-ray data. The algorithm, part of a program called LEXTRCT, searches for regions of a given size that are above a minimum signal to noise ratio. The algorithm allows selected pixels to be excluded from the source-finding, thus allowing exclusion of saturated pixels (from flares and/or active regions). For Chandra data the noise is determined by photon counting statistics, whereas solar telescopes typically integrate a flux. Thus the calculated signal-to-noise ratio is incorrect, but we find we can scale the number to get reasonable results. For example, Nakakubo and Hara (1998) find 297 bright points in a September 11, 1996 Yohkoh image; with judicious selection of signal-to-noise ratio, our algorithm finds 300 sources. To further assess the efficacy of the algorithm, we analyze a SOHO/EIT image (195 Angstroms) and compare results with those published in the literature (McIntosh and Gurman, 2005). Finally, we analyze three sets of data from Hinode, representing different parts of the decline to minimum of the solar cycle.

Development of a high brightness ion source for IFMIF and preliminary test results

International Nuclear Information System (INIS)

Iga, Takashi; Okumura, Yoshikazu; Kashiwagi, Mieko

2001-05-01

Development of a high brightness ion source for the 40MeV/250mA deuteron beam accelerator, IFMIF, is in progress at JAERI. A prototype ion source using hot filament cathodes has been developed. This ion source consists of a multi-cusp plasma generator and a two-stage accelerator. Beam optics has been investigated at the energy of up to 60keV. Experimental results of the beam optics agreed well with the simulation by assuming that the equivalent ion mass is 2.38. Ion beam of 60keV/100mA H+, which corresponds to ion beam of 100keV/220mA D+, was obtained with optimum perveance (minimum divergence). This result indicates that the current requirement for the IFMIF ion source would be satisfied with this ion source. (author)

The ASAS-SN bright supernova catalogue - III. 2016

DEFF Research Database (Denmark)

Holoien, T. W. -S.; Brown, J. S.; Stanek, K. Z.

2017-01-01

This catalogue summarizes information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (m(peak)d......This catalogue summarizes information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (m(peak)d...

The HST/ACS Coma Cluster Survey. II. Data Description and Source Catalogs

Science.gov (United States)

Hammer, Derek; Kleijn, Gijs Verdoes; Hoyos, Carlos; Den Brok, Mark; Balcells, Marc; Ferguson, Henry C.; Goudfrooij, Paul; Carter, David; Guzman, Rafael; Peletier, Reynier F.;

Bright optical synchrotron counterpart of the western hot spot in Pictor A

International Nuclear Information System (INIS)

Roeser, H.J.; Meisenheimer, K.; Royal Observatory, Edinburgh, Scotland)

1987-01-01

A B = 19.5 mag bright, highly polarized object was detected close to the western hot spot in Pictor A during an optical polarization survey of radio hot spots in classical double radio sources. The unresolved source exhibits a featureless continuum between 400 and 800 nm and is identified as the optical counterpart of the radio hot spot. It is surrounded by optical filaments aligned roughly perpendicular to the source axis. The hot spot is also marginally detected in an Einstein IPC frame. 17 references

MILAGRO OBSERVATIONS OF MULTI-TeV EMISSION FROM GALACTIC SOURCES IN THE FERMI BRIGHT SOURCE LIST

International Nuclear Information System (INIS)

Abdo, A. A.; Linnemann, J. T.; Allen, B. T.; Chen, C.; Aune, T.; Berley, D.; Goodman, J. A.; Christopher, G. E.; Kolterman, B. E.; Mincer, A. I.; Nemethy, P.; DeYoung, T.; Dingus, B. L.; Hoffman, C. M.; Ellsworth, R. W.; Gonzalez, M. M.; Hays, E.; McEnery, J. E.; Huentemeyer, P. H.; Morgan, T.

2009-01-01

We present the result of a search of the Milagro sky map for spatial correlations with sources from a subset of the recent Fermi Bright Source List (BSL). The BSL consists of the 205 most significant sources detected above 100 MeV by the Fermi Large Area Telescope. We select sources based on their categorization in the BSL, taking all confirmed or possible Galactic sources in the field of view of Milagro. Of the 34 Fermi sources selected, 14 are observed by Milagro at a significance of 3 standard deviations or more. We conduct this search with a new analysis which employs newly optimized gamma-hadron separation and utilizes the full eight-year Milagro data set. Milagro is sensitive to gamma rays with energy from 1 to 100 TeV with a peak sensitivity from 10 to 50 TeV depending on the source spectrum and declination. These results extend the observation of these sources far above the Fermi energy band. With the new analysis and additional data, multi-TeV emission is definitively observed associated with the Fermi pulsar, J2229.0+6114, in the Boomerang pulsar wind nebula (PWN). Furthermore, an extended region of multi-TeV emission is associated with the Fermi pulsar, J0634.0+1745, the Geminga pulsar.

Time-resolved brightness measurements by streaking

Science.gov (United States)

Torrance, Joshua S.; Speirs, Rory W.; McCulloch, Andrew J.; Scholten, Robert E.

2018-03-01

Brightness is a key figure of merit for charged particle beams, and time-resolved brightness measurements can elucidate the processes involved in beam creation and manipulation. Here we report on a simple, robust, and widely applicable method for the measurement of beam brightness with temporal resolution by streaking one-dimensional pepperpots, and demonstrate the technique to characterize electron bunches produced from a cold-atom electron source. We demonstrate brightness measurements with 145 ps temporal resolution and a minimum resolvable emittance of 40 nm rad. This technique provides an efficient method of exploring source parameters and will prove useful for examining the efficacy of techniques to counter space-charge expansion, a critical hurdle to achieving single-shot imaging of atomic scale targets.

Modal evaluation of the anthropogenic night sky brightness at arbitrary distances from a light source

International Nuclear Information System (INIS)

Bará, Salvador; Ribas, Salvador J; Kocifaj, Miroslav

2015-01-01

The artificial emissions of light contribute to a high extent to the observed brightness of the night sky in many places of the world. Determining the all-sky radiance of anthropogenic origin requires solving the radiative transfer equation for ground-level light sources, generally resorting to a double-scattering approximation in order to account for the observed radiance patterns with a reasonable degree of accuracy. Since the all-sky radiance distribution produced by an elementary light source depends on the distance to the observer in a way that is not immediately obvious, the contributions of sources located at different distances have to be computed on an individual basis, solving for each one the corresponding scattering integrals. In this paper we show that these calculations may be significantly alleviated by using a modal approach, whereby the hemispheric night-sky radiance is expanded in terms of a convenient basis of two-dimensional (2D) orthogonal functions. Since the modal coefficients of this expansion do vary smoothly with the distance to the observer, the all-sky brightness distributions produced by light sources located at arbitrary intermediate distances can be efficiently estimated by interpolation, provided that the coefficients at a discrete set of distances are accurately determined beforehand. (paper)

Search for the sources of the solar wind in the 9.1 cm brightness temperature

International Nuclear Information System (INIS)

George, R.G.

1975-01-01

The sources of solar wind streams have been the object of intensive research for many years, but the various ideas of where and how streams originate on the sun are still incomplete and contradictory. The present study is an attempt to find the solar wind sources by mathematically approximating the 9.1 cm brightness temperature which would be expected at the foot of spacecraft-measured solar wind streams and by then comparing it with actual radio brightness temperature measurements. Several significant results were found from an analysis of the correlation results. Most plasma emanating from the sun was found to come from high solar latitudes and to deviate significantly from the normally expected east-west path in the low corona. Magnetic channelng causes correlation studies to fail when the sun's magnetic configuration is unstable. The travel time of the plasma from the sun's 9.1 cm emission level to the earth is often more than a month

The Extremely Luminous Quasar Survey (ELQS) in SDSS and the high-z bright-end Quasar Luminosity Function

Science.gov (United States)

Schindler, Jan-Torge; Fan, Xiaohui; McGreer, Ian

2018-01-01

Studies of the most luminous quasars at high redshift directly probe the evolution of the most massive black holes in the early Universe and their connection to massive galaxy formation. Unfortunately, extremely luminous quasars at high redshift are very rare objects. Only wide area surveys have a chance to constrain their population. The Sloan Digital Sky Survey (SDSS) nd the Baryon Oscillation Spectroscopic Survey (BOSS) have so far provided the most widely adopted measurements of the type I quasar luminosity function (QLF) at z>3. However, a careful re-examination of the SDSS quasar sample revealed that the SDSS quasar selection is in fact missing a significant fraction of $z~3$ quasars at the brightest end.We have identified the purely optical color selection of SDSS, where quasars at these redshifts are strongly contaminated by late-type dwarfs, and the spectroscopic incompleteness of the SDSS footprint as the main reasons. Therefore we have designed the Extremely Luminous Quasar Survey (ELQS), based on a novel near-infrared JKW2 color cut using WISE AllWISE and 2MASS all-sky photometry, to yield high completeness for very bright (i < 18.0) quasars in the redshift range of 2.8<= z<=5.0. It effectively uses Random Forest machine-learning algorithms on SDSS and WISE photometry for quasar-star classification and photometric redshift estimation.The ELQS is spectroscopically following up ~230 new quasar candidates in an area of ~12000 deg2 in the SDSS footprint, to obtain a well-defined and complete quasar sample for an accurate measurement of the bright-end quasar luminosity function (QLF) at 2.8<= z<=5.0. So far the ELQS has identified 75 bright new quasars in this redshift range and observations of the fall sky will continue until the end of the year. At the AAS winter meeting we will present the full spectroscopic results of the survey, including a re-estimation and extension of the high-z QLF toward higher luminosities.

A bright single-photon source based on a photonic trumpet

DEFF Research Database (Denmark)

Munsch, Mathieu; Malik, Nitin S.; Bleuse, Joël

Fiber-like photonic nanowires, which are optical waveguides made of a high refractive index material n, have recently emerged as non-resonant systems providing an efficient spontaneous emission (SE) control. When they embed a quantum emitter like a quantum dot (QD), they find application to the r......Fiber-like photonic nanowires, which are optical waveguides made of a high refractive index material n, have recently emerged as non-resonant systems providing an efficient spontaneous emission (SE) control. When they embed a quantum emitter like a quantum dot (QD), they find application...... to the realization of bright sources of quantum light and, reversibly, provide an efficient interface between propagating photons and the QD. For a wire diameter ∼ λ/n (λ is the operation wavelength), the fraction of QD SE coupled to the fundamental guided mode exceeds 90%. The collection of the photons can...... be brought close to unity with a proper engineering of the wire ends. In particular, a tapering of the top wire end is necessary to achieve a directive far-field emission pattern [1]. Recently, we have realized a single-photon source featuring a needle-like taper. The source efficiency, though record...

Development of a high brightness ultrafast Transmission Electron Microscope based on a laser-driven cold field emission source.

Science.gov (United States)

Houdellier, F; Caruso, G M; Weber, S; Kociak, M; Arbouet, A

2018-03-01

We report on the development of an ultrafast Transmission Electron Microscope based on a cold field emission source which can operate in either DC or ultrafast mode. Electron emission from a tungsten nanotip is triggered by femtosecond laser pulses which are tightly focused by optical components integrated inside a cold field emission source close to the cathode. The properties of the electron probe (brightness, angular current density, stability) are quantitatively determined. The measured brightness is the largest reported so far for UTEMs. Examples of imaging, diffraction and spectroscopy using ultrashort electron pulses are given. Finally, the potential of this instrument is illustrated by performing electron holography in the off-axis configuration using ultrashort electron pulses. Copyright © 2017 Elsevier B.V. All rights reserved.

Lamp spectrum and spatial brightness at photopic levels

DEFF Research Database (Denmark)

Fotios, Steve; Atli, Deniz; Cheal, Chris

2015-01-01

Light sources are available in a variety of spectral power distributions (SPDs) and this affects spatial brightness in a manner not predicted by quantities such as illuminance. Tuning light source SPD to better match the sensitivity of visual perception may allow the same spatial brightness but a...

Micro-fresnel structures for microscopy of laser generated bright x-ray sources

International Nuclear Information System (INIS)

Ceglio, N.M.; Shavers, D.C.; Flanders, D.C.; Smith, H.I.

1979-01-01

A brief parametric survey of the x-ray characteristics of a gold micro-disk irradiated at 3 x 10 14 watt/cm 2 by a 1 nsec Nd-glass laser pulse has been provided as an example of a laser generated bright x-ray source. It was shown that a simple phenomenological model of the laser generated x-ray source as a microscopic equilibrium plasma radiating as a blackbody for a finite time determined by its hydrodynamic disassembly and radiation losses, serves to provide an adequate approximation to the x-ray characteristics of such sources. The current state of x-ray microscopy within the LLL laser fusion program was briefly reviewed. Kirpatrick--Baez grazing incidence reflection x-ray microscopes are being used to provide 3 to 5 μm resolution, broadband images (ΔE/E approx. 0.3) over a spectral range from .6 keV to 3.5 keV. Zone Plate Coded Imaging is used to provide 5 to 10 μm resolution, broadband (ΔE/E approx. 0.5) images over a spectral range from 3 keV to 50 keV. Efficient x-ray lensing elements with anticipated submicron resolution are being developed for narrowband (ΔE/E approx. 10 -2 ) imaging applications over a spectral range .1 keV to 8 keV. The x-ray lens design is that of a transmission blazed Fresnel phase plate. Micro--Fresnel zone plates with 3200 A minimum linewidth have been fabricated and preliminary resolution tests begun. The first resolution test pattern, having minimum linewidth of 2.5 μm, was imaged in lambda = 8.34 A light with no difficulty. Newer test patterns with submicron minimum line are being prepared for the next stage of resolution testing. An off-axis Fresnel zone plate with 1600 A minimum linewidth is presently being fabricated for use as an imaging spectrometer in order to provide spatially separated, chromatically distinct images of characteristic line emissions from laser fusion targets

The All Sky Automated Survey. The Catalog of Bright Variable Stars in the I-band, South of Declination +28o

Science.gov (United States)

Sitek, M.; Pojmański, G.

2014-06-01

This paper presents the results of our extensive search for the bright variable stars in approximately 30 000 square degrees of the south sky in the I-band data collected by 9o×9o camera of the All Sky Automated Survey between 2002 and 2009. Lists of over 27 000 variable stars brighter than 9 mag at maximum light, with amplitudes ranging from 0.02 mag to 7 mag and variability time-scales from hours to years, as well as corresponding light curves are provided. Automated classification algorithm based on stellar properties (period, Fourier coefficients, 2MASS J, H, K, colors, ASAS V-band data) was used to roughly classify objects. Despite low spatial resolution of the ASAS data (≍15'') we cross-identified all objects with other available data sources. Coordinates of the most probable 2MASS counterparts are provided. 27 705 stars brighter than I=9 mag were found to be variable, of which 7842 objects were detected to be variable for the first time. Brief statistics and discussion of the presented data is provided. All the photometric data is available over the Internet at http://www.astrouw.edu.pl/ gp/asas/AsasBrightI.html

Electron beam brightness with field immersed emission

International Nuclear Information System (INIS)

Boyd, J.K.; Neil, V.K.

1985-01-01

The beam quality or brightness of an electron beam produced with field immersed emission is studied with two models. First, an envelope formulation is used to determine the scaling of brightness with current, magnetic field and cathode radius, and examine the equilibrium beam radius. Second, the DPC computer code is used to calculate the brightness of two electron beam sources

Second ROSAT all-sky survey (2RXS) source catalogue

Science.gov (United States)

Boller, Th.; Freyberg, M. J.; Trümper, J.; Haberl, F.; Voges, W.; Nandra, K.

2016-04-01

Aims: We present the second ROSAT all-sky survey source catalogue, hereafter referred to as the 2RXS catalogue. This is the second publicly released ROSAT catalogue of point-like sources obtained from the ROSAT all-sky survey (RASS) observations performed with the position-sensitive proportional counter (PSPC) between June 1990 and August 1991, and is an extended and revised version of the bright and faint source catalogues. Methods: We used the latest version of the RASS processing to produce overlapping X-ray images of 6.4° × 6.4° sky regions. To create a source catalogue, a likelihood-based detection algorithm was applied to these, which accounts for the variable point-spread function (PSF) across the PSPC field of view. Improvements in the background determination compared to 1RXS were also implemented. X-ray control images showing the source and background extraction regions were generated, which were visually inspected. Simulations were performed to assess the spurious source content of the 2RXS catalogue. X-ray spectra and light curves were extracted for the 2RXS sources, with spectral and variability parameters derived from these products. Results: We obtained about 135 000 X-ray detections in the 0.1-2.4 keV energy band down to a likelihood threshold of 6.5, as adopted in the 1RXS faint source catalogue. Our simulations show that the expected spurious content of the catalogue is a strong function of detection likelihood, and the full catalogue is expected to contain about 30% spurious detections. A more conservative likelihood threshold of 9, on the other hand, yields about 71 000 detections with a 5% spurious fraction. We recommend thresholds appropriate to the scientific application. X-ray images and overlaid X-ray contour lines provide an additional user product to evaluate the detections visually, and we performed our own visual inspections to flag uncertain detections. Intra-day variability in the X-ray light curves was quantified based on the

TH-CD-207B-01: BEST IN PHYSICS (IMAGING): Development of High Brightness Multiple-Pixel X-Ray Source Using Oxide Coated Cathodes

Energy Technology Data Exchange (ETDEWEB)

Kandlakunta, P; Pham, R; Zhang, T [Washington University School of Medicine, St. Louis, MO (United States)

2016-06-15

Purpose: To develop and characterize a high brightness multiple-pixel thermionic emission x-ray (MPTEX) source. Methods: Multiple-pixel x-ray sources allow for designs of novel x-ray imaging techniques, such as fixed gantry CT, digital tomosynthesis, tetrahedron beam computed tomography, etc. We are developing a high-brightness multiple-pixel thermionic emission x-ray (MPTEX) source based on oxide coated cathodes. Oxide cathode is chosen as the electron source due to its high emission current density and low operating temperature. A MPTEX prototype has been developed which may contain up to 41 micro-rectangular oxide cathodes in 4 mm pixel spacing. Electronics hardware was developed for source control and switching. The cathode emission current was evaluated and x-ray measurements were performed to estimate the focal spot size. Results: The oxide cathodes were able to produce ∼110 mA cathode current in pulse mode which corresponds to an emission current density of 0.55 A/cm{sup 2}. The maximum kVp of the MPTEX prototype currently is limited to 100 kV due to the rating of high voltage feedthrough. Preliminary x-ray measurements estimated the focal spot size as 1.5 × 1.3 mm{sup 2}. Conclusion: A MPTEX source was developed with thermionic oxide coated cathodes and preliminary source characterization was successfully performed. The MPTEX source is able to produce an array of high brightness x-ray beams with a fast switching speed.

TH-CD-207B-01: BEST IN PHYSICS (IMAGING): Development of High Brightness Multiple-Pixel X-Ray Source Using Oxide Coated Cathodes

International Nuclear Information System (INIS)

Kandlakunta, P; Pham, R; Zhang, T

2016-01-01

Purpose: To develop and characterize a high brightness multiple-pixel thermionic emission x-ray (MPTEX) source. Methods: Multiple-pixel x-ray sources allow for designs of novel x-ray imaging techniques, such as fixed gantry CT, digital tomosynthesis, tetrahedron beam computed tomography, etc. We are developing a high-brightness multiple-pixel thermionic emission x-ray (MPTEX) source based on oxide coated cathodes. Oxide cathode is chosen as the electron source due to its high emission current density and low operating temperature. A MPTEX prototype has been developed which may contain up to 41 micro-rectangular oxide cathodes in 4 mm pixel spacing. Electronics hardware was developed for source control and switching. The cathode emission current was evaluated and x-ray measurements were performed to estimate the focal spot size. Results: The oxide cathodes were able to produce ∼110 mA cathode current in pulse mode which corresponds to an emission current density of 0.55 A/cm 2 . The maximum kVp of the MPTEX prototype currently is limited to 100 kV due to the rating of high voltage feedthrough. Preliminary x-ray measurements estimated the focal spot size as 1.5 × 1.3 mm 2 . Conclusion: A MPTEX source was developed with thermionic oxide coated cathodes and preliminary source characterization was successfully performed. The MPTEX source is able to produce an array of high brightness x-ray beams with a fast switching speed.

Mechanical design and fabrication of the VHF-gun, the Berkeley normal-conducting continuous-wave high-brightness electron source

Science.gov (United States)

Wells, R. P.; Ghiorso, W.; Staples, J.; Huang, T. M.; Sannibale, F.; Kramasz, T. D.

2016-02-01

A high repetition rate, MHz-class, high-brightness electron source is a key element in future high-repetition-rate x-ray free electron laser-based light sources. The VHF-gun, a novel low frequency radio-frequency gun, is the Lawrence Berkeley National Laboratory (LBNL) response to that need. The gun design is based on a normal conducting, single cell cavity resonating at 186 MHz in the VHF band and capable of continuous wave operation while still delivering the high accelerating fields at the cathode required for the high brightness performance. The VHF-gun was fabricated and successfully commissioned in the framework of the Advanced Photo-injector EXperiment, an injector built at LBNL to demonstrate the capability of the gun to deliver the required beam quality. The basis for the selection of the VHF-gun technology, novel design features, and fabrication techniques are described.

Detection of a Very Bright Source Close to the LMC Supernova SN 1987A: Erratum

Science.gov (United States)

Nisenson, P.; Papaliolios, C.; Karovska, M.; Noyes, R.

1988-01-01

In the Letter "Detection of a Very Bright Source Close to the LMC Supernova SN 1987A" by P. Nisenson, C. Papaliolios, M. Karovska, and R. Noyes (1987 Ap. J. [Letters], 320, L15), two of the figure labels for Figure 1 were inadvertently transposed in the production process. A corrected version of the figure appears as Plate L4. The Journal regrets the error.

Observations of variable and transient X-ray sources with the Ariel V Sky Survey Experiment

International Nuclear Information System (INIS)

Pounds, K.A.; Cooke, B.A.; Ricketts, M.J.; Turner, M.J.; Peacock, A.; Eadie, G.

1976-01-01

Results obtained during the first six months in orbit of Aerial V with the Leicester Sky Survey are reviewed. Among 80 sources found by a scan of the Milky Way, 16 are new, and 11 UHURU sources in the scanned region are not detected. Some of these sources may be transient. The light curve of Cen X-3 in a binary cycle shows a dip between phase 0.5 and 0.75, and a secondary maximum at the centre of the dip. The dip and the maximum get progressively weaker in the succeeding cycles. These features are interpreted in terms of the stellar wind accretion model. Cyg X-1 observation for 14 days gives a broad minimum around superior conjunction. Four bright transient sources of nova-like light curves have been observed. The light curves and the spectra are given for TrA X-1 (A1524-62) and Tau X-T (A0535+26). (Auth.)

Searching for Extragalactic Sources in the VISTA Variables in the Vía Láctea Survey

Science.gov (United States)

Baravalle, Laura D.; Alonso, M. Victoria; Nilo Castellón, José Luis; Beamín, Juan Carlos; Minniti, Dante

2018-01-01

We search for extragalactic sources in the VISTA Variables in the Vía Láctea survey that are hidden by the Galaxy. Herein, we describe our photometric procedure to find and characterize extragalactic objects using a combination of SExtractor and PSFEx. It was applied in two tiles of the survey: d010 and d115, without previous extragalactic IR detections, in order to obtain photometric parameters of the detected sources. The adopted criteria to define extragalactic candidates include CLASSSTAR 0.002 and the colors: 0.5 0.44 mag. We detected 345 and 185 extragalactic candidates in the d010 and d115 tiles, respectively. All of them were visually inspected and confirmed to be galaxies. In general, they are small and more circular objects, due to the near-IR sensitivity to select more compact objects with higher surface brightness. The procedure will be used to identify extragalactic objects in other tiles of the VVV disk, which will allow us to study the distribution of galaxies and filaments hidden by the Milky Way.

High brightness--multiple beamlets source for patterned X-ray production

Science.gov (United States)

Leung, Ka-Ngo [Hercules, CA; Ji, Qing [Albany, CA; Barletta, William A [Oakland, CA; Jiang, Ximan [El Cerrito, CA; Ji, Lili [Albany, CA

2009-10-27

Techniques for controllably directing beamlets to a target substrate are disclosed. The beamlets may be either positive ions or electrons. It has been shown that beamlets may be produced with a diameter of 1 .mu.m, with inter-aperture spacings of 12 .mu.m. An array of such beamlets, may be used for maskless lithography. By step-wise movement of the beamlets relative to the target substrate, individual devices may be directly e-beam written. Ion beams may be directly written as well. Due to the high brightness of the beamlets from extraction from a multicusp source, exposure times for lithographic exposure are thought to be minimized. Alternatively, the beamlets may be electrons striking a high Z material for X-ray production, thereafter collimated to provide patterned X-ray exposures such as those used in CAT scans. Such a device may be used for remote detection of explosives.

Investigating the Bright End of LSST Photometry

Science.gov (United States)

Ojala, Elle; Pepper, Joshua; LSST Collaboration

2018-01-01

The Large Synoptic Survey Telescope (LSST) will begin operations in 2022, conducting a wide-field, synoptic multiband survey of the southern sky. Some fraction of objects at the bright end of the magnitude regime observed by LSST will overlap with other wide-sky surveys, allowing for calibration and cross-checking between surveys. The LSST is optimized for observations of very faint objects, so much of this data overlap will be comprised of saturated images. This project provides the first in-depth analysis of saturation in LSST images. Using the PhoSim package to create simulated LSST images, we evaluate saturation properties of several types of stars to determine the brightness limitations of LSST. We also collect metadata from many wide-field photometric surveys to provide cross-survey accounting and comparison. Additionally, we evaluate the accuracy of the PhoSim modeling parameters to determine the reliability of the software. These efforts will allow us to determine the expected useable data overlap between bright-end LSST images and faint-end images in other wide-sky surveys. Our next steps are developing methods to extract photometry from saturated images.This material is based upon work supported in part by the National Science Foundation through Cooperative Agreement 1258333 managed by the Association of Universities for Research in Astronomy (AURA), and the Department of Energy under Contract No. DE-AC02-76SF00515 with the SLAC National Accelerator Laboratory. Additional LSST funding comes from private donations, grants to universities, and in-kind support from LSSTC Institutional Members.Thanks to NSF grant PHY-135195 and the 2017 LSSTC Grant Award #2017-UG06 for making this project possible.

Bright broadband coherent fiber sources emitting strongly blue-shifted resonant dispersive wave pulses

DEFF Research Database (Denmark)

Tu, Haohua; Lægsgaard, Jesper; Zhang, Rui

2013-01-01

We predict and realize the targeted wavelength conversion from the 1550-nm band of a fs Er:fiber laser to an isolated band inside 370-850 nm, corresponding to a blue-shift of 700-1180 nm. The conversion utilizes resonant dispersive wave generation in widely available optical fibers with good...... efficiency (~7%). The converted band has a large pulse energy (~1 nJ), high spectral brightness (~1 mW/nm), and broad Gaussian-like spectrum compressible to clean transform-limited ~17 fs pulses. The corresponding coherent fiber sources open up portable applications of optical parametric oscillators and dual......-output synchronized ultrafast lasers....

Sources of the Radio Background Considered

Energy Technology Data Exchange (ETDEWEB)

Singal, J.; /KIPAC, Menlo Park /Stanford U.; Stawarz, L.; /KIPAC, Menlo Park /Stanford U. /Jagiellonian U., Astron. Observ.; Lawrence, A.; /Edinburgh U., Inst. Astron. /KIPAC, Menlo Park /Stanford U.; Petrosian, V.; /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.

2011-08-22

We investigate possible origins of the extragalactic radio background reported by the ARCADE 2 collaboration. The surface brightness of the background is several times higher than that which would result from currently observed radio sources. We consider contributions to the background from diffuse synchrotron emission from clusters and the intergalactic medium, previously unrecognized flux from low surface brightness regions of radio sources, and faint point sources below the flux limit of existing surveys. By examining radio source counts available in the literature, we conclude that most of the radio background is produced by radio point sources that dominate at sub {mu}Jy fluxes. We show that a truly diffuse background produced by elections far from galaxies is ruled out because such energetic electrons would overproduce the observed X-ray/{gamma}-ray background through inverse Compton scattering of the other photon fields. Unrecognized flux from low surface brightness regions of extended radio sources, or moderate flux sources missed entirely by radio source count surveys, cannot explain the bulk of the observed background, but may contribute as much as 10%. We consider both radio supernovae and radio quiet quasars as candidate sources for the background, and show that both fail to produce it at the observed level because of insufficient number of objects and total flux, although radio quiet quasars contribute at the level of at least a few percent. We conclude that the most important population for production of the background is likely ordinary starforming galaxies above redshift 1 characterized by an evolving radio far-infrared correlation, which increases toward the radio loud with redshift.

Investigating a population of infrared-bright gamma-ray burst host galaxies

Science.gov (United States)

Chrimes, Ashley A.; Stanway, Elizabeth R.; Levan, Andrew J.; Davies, Luke J. M.; Angus, Charlotte R.; Greis, Stephanie M. L.

2018-04-01

We identify and explore the properties of an infrared-bright gamma-ray burst (GRB) host population. Candidate hosts are selected by coincidence with sources in WISE, with matching to random coordinates and a false alarm probability analysis showing that the contamination fraction is ˜ 0.5. This methodology has already identified the host galaxy of GRB 080517. We combine survey photometry from Pan-STARRS, SDSS, APASS, 2MASS, GALEX and WISE with our own WHT/ACAM and VLT/X-shooter observations to classify the candidates and identify interlopers. Galaxy SED fitting is performed using MAGPHYS, in addition to stellar template fitting, yielding 13 possible IR-bright hosts. A further 7 candidates are identified from previously published work. We report a candidate host for GRB 061002, previously unidentified as such. The remainder of the galaxies have already been noted as potential hosts. Comparing the IR-bright population properties including redshift z, stellar mass M⋆, star formation rate SFR and V-band attenuation AV to GRB host catalogues in the literature, we find that the infrared-bright population is biased toward low z, high M⋆ and high AV. This naturally arises from their initial selection - local and dusty galaxies are more likely to have the required IR flux to be detected in WISE. We conclude that while IR-bright GRB hosts are not a physically distinct class, they are useful for constraining existing GRB host populations, particularly for long GRBs.

Brightness of synchrotron radiation from wigglers

International Nuclear Information System (INIS)

Geloni, Gianluca; Kocharyan, Vitali; Saldin, Evgeni

2014-12-01

According to literature, while calculating the brightness of synchrotron radiation from wigglers, one needs to account for the so called 'depth-of-field' effects. In fact, the particle beam cross section varies along the wiggler. It is usually stated that the effective photon source size increases accordingly, while the brightness is reduced. Here we claim that this is a misconception originating from an analysis of the wiggler source based on geometrical arguments, regarded as almost self-evident. According to electrodynamics, depth-of-field effects do not exist: we demonstrate this statement both theoretically and numerically, using a well-known first-principle computer code. This fact shows that under the usually accepted approximations, the description of the wiggler brightness turns out to be inconsistent even qualitatively. Therefore, there is a need for a well-defined procedure for computing the brightness from a wiggler source. We accomplish this task based on the use of a Wigner function formalism. In the geometrical optics limit computations can be performed analytically. Within this limit, we restrict ourselves to the case of the beam size-dominated regime, which is typical for synchrotron radiation facilities in the X-ray wavelength range. We give a direct demonstration of the fact that the apparent horizontal source size is broadened in proportion to the beamline opening angle and to the length of the wiggler. While this effect is well-understood, a direct proof appears not to have been given elsewhere. We consider the problem of the calculation of the wiggler source size by means of numerical simulations alone, which play the same role of an experiment. We report a significant numerical disagreement between exact calculations and approximations currently used in literature.

THE GALACTIC O-STAR SPECTROSCOPIC SURVEY (GOSSS). II. BRIGHT SOUTHERN STARS

International Nuclear Information System (INIS)

Sota, A.; Apellániz, J. Maíz; Alfaro, E. J.; Morrell, N. I.; Barbá, R. H.; Arias, J. I.; Walborn, N. R.; Gamen, R. C.

2014-01-01

We present the second installment of GOSSS, a massive spectroscopic survey of Galactic O stars, based on new homogeneous, high signal-to-noise ratio, R ∼ 2500 digital observations from both hemispheres selected from the Galactic O-Star Catalog (GOSC). In this paper we include bright stars and other objects drawn mostly from the first version of GOSC, all of them south of δ = –20°, for a total number of 258 O stars. We also revise the northern sample of Paper I to provide the full list of spectroscopically classified Galactic O stars complete to B = 8, bringing the total number of published GOSSS stars to 448. Extensive sequences of exceptional objects are given, including the early Of/WN, O Iafpe, Ofc, ON/OC, Onfp, Of?p, and Oe types, as well as double/triple-lined spectroscopic binaries. The new spectral subtype O9.2 is also discussed. The magnitude and spatial distributions of the observed sample are analyzed. We also present new results from OWN, a multi-epoch high-resolution spectroscopic survey coordinated with GOSSS that is assembling the largest sample of Galactic spectroscopic massive binaries ever attained. The OWN data combined with additional information on spectroscopic and visual binaries from the literature indicate that only a very small fraction (if any) of the stars with masses above 15-20 M ☉ are born as single systems. In the future we will publish the rest of the GOSSS survey, which is expected to include over 1000 Galactic O stars

Development and Utilization of Bright Tabletop Sources of Coherent Soft X-Ray Radiation

International Nuclear Information System (INIS)

Rocca, Jorge J.

2005-01-01

This project investigated aspects of the development and utilization of compact XUV sources based on fast capillary discharges and high order harmonic up conversion. These sources are very compact, yet can generate soft x-ray radiation with peak spectral brightness several orders of magnitude larger than a synchrotron beam lines. The work has included the characterization of some of the important parameters that enable the use of these sources in unique applications, such as the degree of spatial coherence and the wavefront characteristics that affect their focusing capabilities. In relation to source development, they have recently completed preliminary work towards exploring the generation of high harmonics in a pre-ionized medium created by a capillary discharge. Since ions are more difficult to ionize than neutral atoms, the use of pre-ionized nonlinear media may lead to the generation of coherent light at > 1 KeV photon energy. Recent application results include the first study of the damage threshold and damage mechanism of XUV mirrors exposed to intense focalized 46.9 nm laser radiation, and the study of the ablation of polymers with soft x-ray laser light

Survey and alignment for the Swiss Light Source

International Nuclear Information System (INIS)

Wei, F.Q.; Dreyer, K.; Fehlmann, U.; Pochon, J.L.; Wrulich, A.

1999-01-01

The Swiss Light Source (SLS) is a dedicated high brightness synchrotron light source currently under construction at the Paul Scherrer Institute (PSI) in Villigen. It will be commissioned in 2001. The accelerator complex includes a 2.4 GeV electron storage ring (SR) with 288 in circumference, a full energy injection booster synchrotron (Booster) and a 100 MeV linear pre-accelerator. The general alignment method and first results of the network measurements are presented. A laser tracker LTD500 is mainly adopted for network measurements and the alignment of storage ring components. (authors)

FERMI/LARGE AREA TELESCOPE BRIGHT GAMMA-RAY SOURCE LIST

International Nuclear Information System (INIS)

Abdo, A. A.; Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W.; Atwood, W. B.; Axelsson, M.; Battelino, M.; Baldini, L.; Bellazzini, R.; Ballet, J.; Band, D. L.; Barbiellini, G.; Bastieri, D.; Baughman, B. M.; Bignami, G. F.; Bonamente, E.

2009-01-01

Following its launch in 2008 June, the Fermi Gamma-ray Space Telescope (Fermi) began a sky survey in August. The Large Area Telescope (LAT) on Fermi in three months produced a deeper and better resolved map of the γ-ray sky than any previous space mission. We present here initial results for energies above 100 MeV for the 205 most significant (statistical significance greater than ∼10σ) γ-ray sources in these data. These are the best characterized and best localized point-like (i.e., spatially unresolved) γ-ray sources in the early mission data.

Fermi Large Area Telescope Bright Gamma-ray Source List

Energy Technology Data Exchange (ETDEWEB)

Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /KIPAC, Menlo Park /SLAC; Ajello, M.; /KIPAC, Menlo Park /SLAC; Atwood, W.B.; /UC, Santa Cruz; Axelsson, M.; /Stockholm U., OKC /Stockholm U.; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Band, D.L.; /NASA, Goddard /NASA, Goddard; Barbiellini, Guido; /INFN, Trieste /Trieste U.; Bastieri, Denis; /INFN, Padua /Padua U.; Bechtol, K.; /KIPAC, Menlo Park /SLAC; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /KIPAC, Menlo Park /SLAC; Bignami, G.F.; /Pavia U.; Bloom, Elliott D.; /KIPAC, Menlo Park /SLAC; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /KIPAC, Menlo Park /SLAC; Bregeon, J.; /INFN, Pisa; Brigida, M.; /Bari U. /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Burnett, Thompson H.; /Washington U., Seattle /Bari U. /INFN, Bari /KIPAC, Menlo Park /SLAC /IASF, Milan /IASF, Milan /DAPNIA, Saclay /ASDC, Frascati /INFN, Perugia /Perugia U. /KIPAC, Menlo Park /SLAC /George Mason U. /Naval Research Lab, Wash., D.C. /NASA, Goddard /KIPAC, Menlo Park /SLAC /INFN, Perugia /Perugia U. /KIPAC, Menlo Park /SLAC /Montpellier U. /Sonoma State U. /Stockholm U., OKC /Royal Inst. Tech., Stockholm /Stockholm U. /KIPAC, Menlo Park /SLAC /ASDC, Frascati /NASA, Goddard /Maryland U. /Naval Research Lab, Wash., D.C. /INFN, Trieste /Pavia U. /Bari U. /INFN, Bari /KIPAC, Menlo Park /SLAC /UC, Santa Cruz /KIPAC, Menlo Park /SLAC /KIPAC, Menlo Park /SLAC /KIPAC, Menlo Park /SLAC /Montpellier U. /Bari U. /INFN, Bari /Ecole Polytechnique /NASA, Goddard; /more authors..

2009-05-15

Following its launch in 2008 June, the Fermi Gamma-ray Space Telescope (Fermi) began a sky survey in August. The Large Area Telescope (LAT) on Fermi in three months produced a deeper and better resolved map of the {gamma}-ray sky than any previous space mission. We present here initial results for energies above 100 MeV for the 205 most significant (statistical significance greater than {approx}10{sigma}) {gamma}-ray sources in these data. These are the best characterized and best localized point-like (i.e., spatially unresolved) {gamma}-ray sources in the early mission data.

A new sample of faint Gigahertz Peaked Spectrum radio sources

NARCIS (Netherlands)

Snellen, IAG; Schilizzi, RT; de Bruyn, AG; Miley, GK; Rengelink, RB; Rottgering, HJ

The Westerbork Northern Sky Survey (WENSS) has been used to select a sample of Gigahertz Peaked Spectrum (GPS) radio sources at flux densities one to two orders of magnitude lower than bright GPS sources investigated in earlier studies. Sources with inverted spectra at frequencies above 325 MHz have

Development of a high brightness, high current SRF photo-electron source for ERL applications

Energy Technology Data Exchange (ETDEWEB)

Neumann, Axel [Helmholtz-Zentrum Berlin (Germany); Collaboration: bERLinPro Team

2016-07-01

Energy recovery linacs (ERL) offer the potential to combine major beam properties of the two main domains of particle accelerators: The low emittance of linear accelerators and the high average beam current of storage rings, while also allowing to compress to short bunches below the ps regime. This makes among other applications ERLs an ideal candidate for future light sources. The beam properties of the ERL are given by the performance of the injection section and hence of the beam source. Helmholtz-Zentrum Berlin is currently designing and building a high average current all superconducting CW driven ERL as a prototype to demonstrate low normalized beam emittance of 1 mm*mrad at 100 mA and short pulses of about 2 ps. In this contribution we discuss the development of this class of a high brightness, high current SRF photo-electron source and present recent commissioning results. Also, alternative approaches at other laboratories are shortly reviewed.

A Survey of Industrial Involvement in Open Source

OpenAIRE

Røsdal, Andreas

2006-01-01

This thesis presents the results of an explorative survey of industrial involvement in open source. The survey is performed in collaboration with participants from the European ITEA project, COSI (Co-development using inner & Open source in Software Intensive products). The survey was performed to explore aspects of industrial involvement in open source, as industrial management of open source project, industrial use of open source components, related development, and communication processes,...

A daytime measurement of the lunar contribution to the night sky brightness in LSST's ugrizy bands-initial results

Science.gov (United States)

Coughlin, Michael; Stubbs, Christopher; Claver, Chuck

2016-06-01

We report measurements from which we determine the spatial structure of the lunar contribution to night sky brightness, taken at the LSST site on Cerro Pachon in Chile. We use an array of six photodiodes with filters that approximate the Large Synoptic Survey Telescope's u, g, r, i, z, and y bands. We use the sun as a proxy for the moon, and measure sky brightness as a function of zenith angle of the point on sky, zenith angle of the sun, and angular distance between the sun and the point on sky. We make a correction for the difference between the illumination spectrum of the sun and the moon. Since scattered sunlight totally dominates the daytime sky brightness, this technique allows us to cleanly determine the contribution to the (cloudless) night sky from backscattered moonlight, without contamination from other sources of night sky brightness. We estimate our uncertainty in the relative lunar night sky brightness vs. zenith and lunar angle to be between 0.3-0.7 mags depending on the passband. This information is useful in planning the optimal execution of the LSST survey, and perhaps for other astronomical observations as well. Although our primary objective is to map out the angular structure and spectrum of the scattered light from the atmosphere and particulates, we also make an estimate of the expected number of scattered lunar photons per pixel per second in LSST, and find values that are in overall agreement with previous estimates.

RELIABLE IDENTIFICATIONS OF ACTIVE GALACTIC NUCLEI FROM THE WISE, 2MASS, AND ROSAT ALL-SKY SURVEYS

Energy Technology Data Exchange (ETDEWEB)

Edelson, R. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Malkan, M., E-mail: rickedelson@gmail.com [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095-1547 (United States)

2012-05-20

We have developed the ''S{sub IX}'' statistic to identify bright, highly likely active galactic nucleus (AGN) candidates solely on the basis of Wide-field Infrared Survey Explorer (WISE), Two Micron All-Sky Survey (2MASS), and ROSAT all-sky survey (RASS) data. This statistic was optimized with data from the preliminary WISE survey and the Sloan Digital Sky Survey, and tested with Lick 3 m Kast spectroscopy. We find that sources with S{sub IX} < 0 have a {approx}>95% likelihood of being an AGN (defined in this paper as a Seyfert 1, quasar, or blazar). This statistic was then applied to the full WISE/2MASS/RASS dataset, including the final WISE data release, to yield the ''W2R'' sample of 4316 sources with S{sub IX} < 0. Only 2209 of these sources are currently in the Veron-Cetty and Veron (VCV) catalog of spectroscopically confirmed AGNs, indicating that the W2R sample contains nearly 2000 new, relatively bright (J {approx}< 16) AGNs. We utilize the W2R sample to quantify biases and incompleteness in the VCV catalog. We find that it is highly complete for bright (J < 14), northern AGNs, but the completeness drops below 50% for fainter, southern samples and for sources near the Galactic plane. This approach also led to the spectroscopic identification of 10 new AGNs in the Kepler field, more than doubling the number of AGNs being monitored by Kepler. The W2R sample contains better than 1 bright AGN every 10 deg{sup 2}, permitting construction of AGN samples in any sufficiently large region of sky.

Degree of polarization and source counts of faint radio sources from Stacking Polarized intensity

International Nuclear Information System (INIS)

Stil, J. M.; George, S. J.; Keller, B. W.; Taylor, A. R.

2014-01-01

We present stacking polarized intensity as a means to study the polarization of sources that are too faint to be detected individually in surveys of polarized radio sources. Stacking offers not only high sensitivity to the median signal of a class of radio sources, but also avoids a detection threshold in polarized intensity, and therefore an arbitrary exclusion of sources with a low percentage of polarization. Correction for polarization bias is done through a Monte Carlo analysis and tested on a simulated survey. We show that the nonlinear relation between the real polarized signal and the detected signal requires knowledge of the shape of the distribution of fractional polarization, which we constrain using the ratio of the upper quartile to the lower quartile of the distribution of stacked polarized intensities. Stacking polarized intensity for NRAO VLA Sky Survey (NVSS) sources down to the detection limit in Stokes I, we find a gradual increase in median fractional polarization that is consistent with a trend that was noticed before for bright NVSS sources, but is much more gradual than found by previous deep surveys of radio polarization. Consequently, the polarized radio source counts derived from our stacking experiment predict fewer polarized radio sources for future surveys with the Square Kilometre Array and its pathfinders.

Energy-exchange collisions of dark-bright-bright vector solitons.

Science.gov (United States)

Radhakrishnan, R; Manikandan, N; Aravinthan, K

2015-12-01

We find a dark component guiding the practically interesting bright-bright vector one-soliton to two different parametric domains giving rise to different physical situations by constructing a more general form of three-component dark-bright-bright mixed vector one-soliton solution of the generalized Manakov model with nine free real parameters. Moreover our main investigation of the collision dynamics of such mixed vector solitons by constructing the multisoliton solution of the generalized Manakov model with the help of Hirota technique reveals that the dark-bright-bright vector two-soliton supports energy-exchange collision dynamics. In particular the dark component preserves its initial form and the energy-exchange collision property of the bright-bright vector two-soliton solution of the Manakov model during collision. In addition the interactions between bound state dark-bright-bright vector solitons reveal oscillations in their amplitudes. A similar kind of breathing effect was also experimentally observed in the Bose-Einstein condensates. Some possible ways are theoretically suggested not only to control this breathing effect but also to manage the beating, bouncing, jumping, and attraction effects in the collision dynamics of dark-bright-bright vector solitons. The role of multiple free parameters in our solution is examined to define polarization vector, envelope speed, envelope width, envelope amplitude, grayness, and complex modulation of our solution. It is interesting to note that the polarization vector of our mixed vector one-soliton evolves in sphere or hyperboloid depending upon the initial parametric choices.

THE STATISTICS OF RADIO ASTRONOMICAL POLARIMETRY: BRIGHT SOURCES AND HIGH TIME RESOLUTION

International Nuclear Information System (INIS)

Van Straten, W.

2009-01-01

A four-dimensional statistical description of electromagnetic radiation is developed and applied to the analysis of radio pulsar polarization. The new formalism provides an elementary statistical explanation of the modal-broadening phenomenon in single-pulse observations. It is also used to argue that the degree of polarization of giant pulses has been poorly defined in past studies. Single- and giant-pulse polarimetry typically involves sources with large flux-densities and observations with high time-resolution, factors that necessitate consideration of source-intrinsic noise and small-number statistics. Self-noise is shown to fully explain the excess polarization dispersion previously noted in single-pulse observations of bright pulsars, obviating the need for additional randomly polarized radiation. Rather, these observations are more simply interpreted as an incoherent sum of covariant, orthogonal, partially polarized modes. Based on this premise, the four-dimensional covariance matrix of the Stokes parameters may be used to derive mode-separated pulse profiles without any assumptions about the intrinsic degrees of mode polarization. Finally, utilizing the small-number statistics of the Stokes parameters, it is established that the degree of polarization of an unresolved pulse is fundamentally undefined; therefore, previous claims of highly polarized giant pulses are unsubstantiated.

Detection of a very bright source close to the LMC supernova SN 1987A

Science.gov (United States)

Nisenson, P.; Papaliolios, C.; Karovska, M.; Noyes, R.

1987-01-01

High angular resolution observations of the supernova in the Large Magellanic Cloud, SN 1987A, have revealed a bright source separated from the SN by approximately 60 mas with a magnitude difference of 2.7 at 656 nm (H-alpha). Speckle imaging techniques were applied to data recorded with the CfA two-dimensional photon counting detector on the CTIO 4 m telescope on March 25 and April 2 to allow measurements in H-alpha on both nights and at 533 nm and 450 nm on the second night. The nature of this object is as yet unknown, though it is almost certainly a phenomenon related to the SN.

The JCMT Transient Survey: Data Reduction and Calibration Methods

International Nuclear Information System (INIS)

Mairs, Steve; Lane, James; Johnstone, Doug; Kirk, Helen; Lacaille, Kevin; Chapman, Scott; Bower, Geoffrey C.; Bell, Graham S.; Graves, Sarah

2017-01-01

Though there has been a significant amount of work investigating the early stages of low-mass star formation in recent years, the evolution of the mass assembly rate onto the central protostar remains largely unconstrained. Examining in depth the variation in this rate is critical to understanding the physics of star formation. Instabilities in the outer and inner circumstellar disk can lead to episodic outbursts. Observing these brightness variations at infrared or submillimeter wavelengths constrains the current accretion models. The JCMT Transient Survey is a three-year project dedicated to studying the continuum variability of deeply embedded protostars in eight nearby star-forming regions at a one-month cadence. We use the SCUBA-2 instrument to simultaneously observe these regions at wavelengths of 450 and 850 μ m. In this paper, we present the data reduction techniques, image alignment procedures, and relative flux calibration methods for 850 μ m data. We compare the properties and locations of bright, compact emission sources fitted with Gaussians over time. Doing so, we achieve a spatial alignment of better than 1″ between the repeated observations and an uncertainty of 2%–3% in the relative peak brightness of significant, localized emission. This combination of imaging performance is unprecedented in ground-based, single-dish submillimeter observations. Finally, we identify a few sources that show possible and confirmed brightness variations. These sources will be closely monitored and presented in further detail in additional studies throughout the duration of the survey.

The JCMT Transient Survey: Data Reduction and Calibration Methods

Energy Technology Data Exchange (ETDEWEB)

Mairs, Steve; Lane, James [Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8P 1A1 (Canada); Johnstone, Doug; Kirk, Helen [NRC Herzberg Astronomy and Astrophysics, 5071 West Saanich Road, Victoria, BC, V9E 2E7 (Canada); Lacaille, Kevin; Chapman, Scott [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 4R2 (Canada); Bower, Geoffrey C. [Academia Sinica Institute of Astronomy and Astrophysics, 645 N. A‘ohōkū Place, Hilo, HI 96720 (United States); Bell, Graham S.; Graves, Sarah, E-mail: smairs@uvic.ca [East Asian Observatory, 660 North A‘ohōkū Place, University Park, Hilo, Hawaii 96720 (United States); Collaboration: JCMT Transient Team

2017-07-01

Though there has been a significant amount of work investigating the early stages of low-mass star formation in recent years, the evolution of the mass assembly rate onto the central protostar remains largely unconstrained. Examining in depth the variation in this rate is critical to understanding the physics of star formation. Instabilities in the outer and inner circumstellar disk can lead to episodic outbursts. Observing these brightness variations at infrared or submillimeter wavelengths constrains the current accretion models. The JCMT Transient Survey is a three-year project dedicated to studying the continuum variability of deeply embedded protostars in eight nearby star-forming regions at a one-month cadence. We use the SCUBA-2 instrument to simultaneously observe these regions at wavelengths of 450 and 850 μ m. In this paper, we present the data reduction techniques, image alignment procedures, and relative flux calibration methods for 850 μ m data. We compare the properties and locations of bright, compact emission sources fitted with Gaussians over time. Doing so, we achieve a spatial alignment of better than 1″ between the repeated observations and an uncertainty of 2%–3% in the relative peak brightness of significant, localized emission. This combination of imaging performance is unprecedented in ground-based, single-dish submillimeter observations. Finally, we identify a few sources that show possible and confirmed brightness variations. These sources will be closely monitored and presented in further detail in additional studies throughout the duration of the survey.

High-brightness electron injectors

International Nuclear Information System (INIS)

Sheffield, R.L.

1987-01-01

Free-electron laser (FEL) oscillators and synchrotron light sources require pulse trains of high peak brightness and, in some applications, high-average power. Recent developments in the technology of photoemissive and thermionic electron sources in rf cavities for electron-linac injector applications offer promising advances over conventional electron injectors. Reduced emittance growth in high peak-current electron injectors may be achieved by using high field strengths and by linearizing the radial component of the cavity electric field at the expense of lower shunt impedance

The brightness of colour.

Directory of Open Access Journals (Sweden)

David Corney

Full Text Available The perception of brightness depends on spatial context: the same stimulus can appear light or dark depending on what surrounds it. A less well-known but equally important contextual phenomenon is that the colour of a stimulus can also alter its brightness. Specifically, stimuli that are more saturated (i.e. purer in colour appear brighter than stimuli that are less saturated at the same luminance. Similarly, stimuli that are red or blue appear brighter than equiluminant yellow and green stimuli. This non-linear relationship between stimulus intensity and brightness, called the Helmholtz-Kohlrausch (HK effect, was first described in the nineteenth century but has never been explained. Here, we take advantage of the relative simplicity of this 'illusion' to explain it and contextual effects more generally, by using a simple Bayesian ideal observer model of the human visual ecology. We also use fMRI brain scans to identify the neural correlates of brightness without changing the spatial context of the stimulus, which has complicated the interpretation of related fMRI studies.Rather than modelling human vision directly, we use a Bayesian ideal observer to model human visual ecology. We show that the HK effect is a result of encoding the non-linear statistical relationship between retinal images and natural scenes that would have been experienced by the human visual system in the past. We further show that the complexity of this relationship is due to the response functions of the cone photoreceptors, which themselves are thought to represent an efficient solution to encoding the statistics of images. Finally, we show that the locus of the response to the relationship between images and scenes lies in the primary visual cortex (V1, if not earlier in the visual system, since the brightness of colours (as opposed to their luminance accords with activity in V1 as measured with fMRI.The data suggest that perceptions of brightness represent a robust

Bright high-repetition-rate source of narrowband extreme-ultraviolet harmonics beyond 22 eV

Energy Technology Data Exchange (ETDEWEB)

Wang, He [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Xu, Yiming [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Ulonska, Stefan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Robinson, Joseph S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Ranitovic, Predrag [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Kaindl, Robert A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division

2015-06-11

Novel table-top sources of extreme-ultraviolet light based on high-harmonic generation yield unique insight into the fundamental properties of molecules, nanomaterials or correlated solids, and enable advanced applications in imaging or metrology. Extending high-harmonic generation to high repetition rates portends great experimental benefits, yet efficient extreme-ultraviolet conversion of correspondingly weak driving pulses is challenging. In this article, we demonstrate a highly-efficient source of femtosecond extreme-ultraviolet pulses at 50-kHz repetition rate, utilizing the ultraviolet second-harmonic focused tightly into Kr gas. In this cascaded scheme, a photon flux beyond ≈3 × 10¹³ s^-1 is generated at 22.3 eV, with 5 × 10^-5 conversion efficiency that surpasses similar harmonics directly driven by the fundamental by two orders-of-magnitude. The enhancement arises from both wavelength scaling of the atomic dipole and improved spatio-temporal phase matching, confirmed by simulations. Finally, spectral isolation of a single 72-meV-wide harmonic renders this bright, 50-kHz extreme-ultraviolet source a powerful tool for ultrafast photoemission, nanoscale imaging and other applications.

High Brightness Electron Guns for Next-Generation Light Sources and Accelerators

International Nuclear Information System (INIS)

H. Bluem; M.D. Cole; J. Rathke; T. Schultheiss; A.M.M. Todd; I. Ben-Zvi; T. Srinivasan-Rao; P. Colestock; D.C. Nguyen; R.L. Wood; L. Young; D. Janssen; J. Lewellen; G. Neil; H.L. Phillips; J.P. Preble

2004-01-01

Advanced Energy Systems continues to develop advanced electron gun and injector concepts. Several of these projects have been previously described, but the progress and status of each will be updated. The project closest to completion is an all superconducting RF (SRF) gun, being developed in collaboration with the Brookhaven National Laboratory, that uses the niobium of the cavity wall itself as the photocathode material. This gun has been fabricated and will shortly be tested with beam. The cavity string for a closely-coupled DC gun and SRF cavity injector that is expected to provide beam quality sufficient for proposed ERL light sources and FELs will be assembled at the Jefferson Laboratory later this year. We are also collaboration with Los Alamos on a prototype CW normal-conducting RF gun with similar performance, that will undergo thermal testing in late 2004. Another CW SRF gun project that uses a high quantum efficiency photocathode, similar to the FZ-Rossendorf approach, has just begun. Finally, we will present the RF design and cold test results for a fully axisymmetric, ultra-high-brightness x-band RF gun

Automated detection of very Low Surface Brightness galaxies in the Virgo Cluster

Science.gov (United States)

Prole, D. J.; Davies, J. I.; Keenan, O. C.; Davies, L. J. M.

2018-04-01

We report the automatic detection of a new sample of very low surface brightness (LSB) galaxies, likely members of the Virgo cluster. We introduce our new software, DeepScan, that has been designed specifically to detect extended LSB features automatically using the DBSCAN algorithm. We demonstrate the technique by applying it over a 5 degree2 portion of the Next-Generation Virgo Survey (NGVS) data to reveal 53 low surface brightness galaxies that are candidate cluster members based on their sizes and colours. 30 of these sources are new detections despite the region being searched specifically for LSB galaxies previously. Our final sample contains galaxies with 26.0 ≤ ⟨μe⟩ ≤ 28.5 and 19 ≤ mg ≤ 21, making them some of the faintest known in Virgo. The majority of them have colours consistent with the red sequence, and have a mean stellar mass of 106.3 ± 0.5M⊙ assuming cluster membership. After using ProFit to fit Sérsic profiles to our detections, none of the new sources have effective radii larger than 1.5 Kpc and do not meet the criteria for ultra-diffuse galaxy (UDG) classification, so we classify them as ultra-faint dwarfs.

The Atacama Cosmology Telescope: Extragalactic Sources at 148 GHz in the 2008 Survey

Science.gov (United States)

Marriage, T. A.; Juin, J. B.; Lin, Y. T.; Marsden, D.; Nolta, M. R.; Partridge, B.; Ade, P. A. R.; Aguirre, P.; Amiri, M.; Appel, J. W.;

Observation of near-infrared surface brightness of the large Magellanic cloud

International Nuclear Information System (INIS)

Hayakawa, Satio; Koizumi, Yutaka; Matsumoto, Toshio; Murakami, Hiroshi; Uyama, Kiichiro.

1981-01-01

The near-infrared surface brightness of the large Magellanic cloud was observed by an infrared telescope carried by a balloon. The balloon flight was made at Australian Balloon Launching Station. The brightness distribution of 2.4 Mu m radiation was obtained. A part of Bar was bright, and the expansion of the contour at the east end of Bar corresponded to the 30 Dor region. Many near-infrared sources distribute in this region. Discussions on the color and brightness of the center of Bar and the 30 Dor region are presented. (Kato, T.)

Surveys of radio sources at 5 GHz

International Nuclear Information System (INIS)

Pauliny-Toth, I.I.K.

1977-01-01

A number of surveys have been carried out at a frequency of 5 GHz at the National Radio Astronomy Observatory (NRAO) and at the Max-Planck-Institut fuer Radioastronomy (MPIFR) with the aim of determining the number-flux density relation for the sources detected and also of obtaining their radio spectra and optical identifications. The surveys fall into two categories: first, the strong source (S) surveys which are intended in due course to cover the whole northern sky and to be complete above a flux density of about 0.6 Jy; second, surveys of limited areas of sky down to lower levels of the flux density. (Auth.)

The Einstein All-Sky IPC slew survey

Science.gov (United States)

Elvis, Martin; Plummer, David; Fabbiano, G.

1989-01-01

The construction of the Einstein All-Sky Imaging Proportional Counter (IPC) slew survey is considered. It contains approximately 1000 sources between 10(exp -12) and 10(exp -10) erg/sq cm/s with a concentration toward the ecliptic poles and away from the galactic plane. Several sizable samples of bright soft X-ray selected objects for follow-up ROSAT and ASTRO-D observations and statistical study are presented. The survey source list is expected to be available by late 1989. Both paper and remote access online data base versions are to be available. An identification program is considered.

The bright-bright and bright-dark mode coupling-based planar metamaterial for plasmonic EIT-like effect

Science.gov (United States)

Yu, Wei; Meng, Hongyun; Chen, Zhangjie; Li, Xianping; Zhang, Xing; Wang, Faqiang; Wei, Zhongchao; Tan, Chunhua; Huang, Xuguang; Li, Shuti

2018-05-01

In this paper, we propose a novel planar metamaterial structure for the electromagnetically induced transparency (EIT)-like effect, which consists of a split-ring resonator (SRR) and a pair of metal strips. The simulated results indicate that a single transparency window can be realized in the symmetry situation, which originates from the bright-bright mode coupling. Further, a dual-band EIT-like effect can be achieved in the asymmetry situation, which is due to the bright-bright mode coupling and bright-dark mode coupling, respectively. Different EIT-like effect can be simultaneously achieved in the proposed structure with the different situations. It is of certain significance for the study of EIT-like effect.

The Einstein objective grating spectrometer survey of galactic binary X-ray sources

Science.gov (United States)

Vrtilek, S. D.; Mcclintock, J. E.; Seward, F. D.; Kahn, S. M.; Wargelin, B. J.

1991-01-01

The results of observations of 22 bright Galactic X-ray point sources are presented, and the most reliable measurements to date of X-ray column densities to these sources are derived. The results are consistent with the idea that some of the objects have a component of column density intrinsic to the source in addition to an interstellar component. The K-edge absorption due to oxygen is clearly detected in 10 of the sources and the Fe L and Ne K edges are detected in a few. The spectra probably reflect emission originating in a collisionally excited region combined with emission from a photoionized region excited directly by the central source.

High-brightness injector modeling

International Nuclear Information System (INIS)

Lewellen, J.W.

2004-01-01

There are many aspects to the successful conception, design, fabrication, and operation of high-brightness electron beam sources. Accurate and efficient modeling of the injector are critical to all phases of the process, from evaluating initial ideas to successful diagnosis of problems during routine operation. The basic modeling tasks will vary from design to design, according to the basic nature of the injector (dc, rf, hybrid, etc.), the type of cathode used (thermionic, photo, field emitter, etc.), and 'macro' factors such as average beam current and duty factor, as well as the usual list of desired beam properties. The injector designer must be at least aware of, if not proficient at addressing, the multitude of issues that arise from these considerations; and, as high-brightness injectors continue to move out of the laboratory, the number of such issues will continue to expand.

150 southern compact and bright-nucleus galaxies

International Nuclear Information System (INIS)

Fairall, A.P.

1977-01-01

Galaxies having regions of exceptionally high surface brightness have been selected from the ESO Quick Blue Survey and investigated by 'grating photography' -direct photography plus low-dispersion slitless spectroscopy. Two new Seyfert galaxies and a peculiar multiple system have been discovered. Differences in red continua are also noted. (author)

High-brightness beamline for x-ray spectroscopy at the ALS

Energy Technology Data Exchange (ETDEWEB)

Perera, R.C.C.; Jones, G. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States); Lindle, D.W. [Univ. of Nevada, Las Vegas, NV (United States)

1997-04-01

Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1-6 keV photon-energy range, designed to achieve the goals of high energy resolution, high flux, and high brightness at the sample. When completed later this year, it will be the first ALS monochromatic hard x-ray beamline, and its brightness will be an order of magnitude higher than presently available in this energy range. In addition, it will provide flux and resolution comparable to any other beamline now in operation. To achieve these goals, two technical improvements, relative to existing x-ray beamlines, were incorporated. First, a somewhat novel optical design for x-rays, in which matched toroidal mirrors are positioned before and after the double-crystal monochromator, was adopted. This configuration allows for high resolution by passing a collimated beam through the monochromator, and for high brightness by focusing the ALS source on the sample with unit magnification. Second, a new {open_quotes}Cowan type{close_quotes} double-crystal monochromator based on the design used at NSLS beamline X-24A was developed. The measured mechanical precision of this new monochromator shows significant improvement over existing designs, without using positional feedback available with piezoelectric devices. Such precision is essential because of the high brightness of the radiation and the long distance (12 m) from the source (sample) to the collimating (focusing) mirror. This combination of features will provide a bright, high resolution, and stable x-ray beam for use in the x-ray spectroscopy program at the ALS.

2011 Radioactive Materials Usage Survey for Unmonitored Point Sources

Energy Technology Data Exchange (ETDEWEB)

Sturgeon, Richard W. [Los Alamos National Laboratory

2012-06-27

This report provides the results of the 2011 Radioactive Materials Usage Survey for Unmonitored Point Sources (RMUS), which was updated by the Environmental Protection (ENV) Division's Environmental Stewardship (ES) at Los Alamos National Laboratory (LANL). ES classifies LANL emission sources into one of four Tiers, based on the potential effective dose equivalent (PEDE) calculated for each point source. Detailed descriptions of these tiers are provided in Section 3. The usage survey is conducted annually; in odd-numbered years the survey addresses all monitored and unmonitored point sources and in even-numbered years it addresses all Tier III and various selected other sources. This graded approach was designed to ensure that the appropriate emphasis is placed on point sources that have higher potential emissions to the environment. For calendar year (CY) 2011, ES has divided the usage survey into two distinct reports, one covering the monitored point sources (to be completed later this year) and this report covering all unmonitored point sources. This usage survey includes the following release points: (1) all unmonitored sources identified in the 2010 usage survey, (2) any new release points identified through the new project review (NPR) process, and (3) other release points as designated by the Rad-NESHAP Team Leader. Data for all unmonitored point sources at LANL is stored in the survey files at ES. LANL uses this survey data to help demonstrate compliance with Clean Air Act radioactive air emissions regulations (40 CFR 61, Subpart H). The remainder of this introduction provides a brief description of the information contained in each section. Section 2 of this report describes the methods that were employed for gathering usage survey data and for calculating usage, emissions, and dose for these point sources. It also references the appropriate ES procedures for further information. Section 3 describes the RMUS and explains how the survey results are

The Next Generation Virgo Cluster Survey (NGVS). XVIII. Measurement and Calibration of Surface Brightness Fluctuation Distances for Bright Galaxies in Virgo (and Beyond)

Science.gov (United States)

Cantiello, Michele; Blakeslee, John P.; Ferrarese, Laura; Côté, Patrick; Roediger, Joel C.; Raimondo, Gabriella; Peng, Eric W.; Gwyn, Stephen; Durrell, Patrick R.; Cuillandre, Jean-Charles

2018-04-01

We describe a program to measure surface brightness fluctuation (SBF) distances to galaxies observed in the Next Generation Virgo Cluster Survey (NGVS), a photometric imaging survey covering 104 deg2 of the Virgo cluster in the u*, g, i, and z bandpasses with the Canada–France–Hawaii Telescope. We describe the selection of the sample galaxies, the procedures for measuring the apparent i-band SBF magnitude {\\overline{m}}i, and the calibration of the absolute Mibar as a function of observed stellar population properties. The multiband NGVS data set provides multiple options for calibrating the SBF distances, and we explore various calibrations involving individual color indices as well as combinations of two different colors. Within the color range of the present sample, the two-color calibrations do not significantly improve the scatter with respect to wide-baseline, single-color calibrations involving u*. We adopt the ({u}* -z) calibration as a reference for the present galaxy sample, with an observed scatter of 0.11 mag. For a few cases that lack good u* photometry, we use an alternative relation based on a combination of (g-i) and (g-z) colors, with only a slightly larger observed scatter of 0.12 mag. The agreement of our measurements with the best existing distance estimates provides confidence that our measurements are accurate. We present a preliminary catalog of distances for 89 galaxies brighter than B T ≈ 13.0 mag within the survey footprint, including members of the background M and W Clouds at roughly twice the distance of the main body of the Virgo cluster. The extension of the present work to fainter and bluer galaxies is in progress.

Recent advances in high-brightness electron guns at AES

International Nuclear Information System (INIS)

Bluem, H.; Todd, A.M.M.; Cole, M.D.; Rathke, J.; Schultheiss, T.

2003-01-01

We describe a number of active Advanced Energy Systems projects pertaining to the development of advanced, high-brightness electron guns for various applications. These projects include a fully superconducting, CW RF gun, nearing test, that utilizes the niobium surface as the photocathode material. An integrated 100 mA, low emittance DC/SRF gun, ideal as an injector for ERL-type light sources and intended as the injector for a 100 kW FEL, is in late design stage. A parallel high-power, CW, normal-conducting L-band RF gun project has just begun. The early performance analysis for this gun also shows good promise as an injector for ERL-type light sources. Lastly, a fully axisymmetric RF gun, operating in X-band, is being studied as a source of extremely bright electron bunches

DETECTION OF AN ULTRA-BRIGHT SUBMILLIMETER GALAXY BEHIND THE SMALL MAGELLANIC CLOUD

Energy Technology Data Exchange (ETDEWEB)

Takekoshi, Tatsuya; Minamidani, Tetsuhiro; Sorai, Kazuo; Habe, Asao [Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Tamura, Yoichi; Kohno, Kotaro [Institute of Astronomy, University of Tokyo, Osawa, Mitaka, Tokyo 181-0015 (Japan); Oogi, Taira [Department of Physics, Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan); Ezawa, Hajime; Komugi, Shinya; Mizuno, Norikazu; Muller, Erik; Kawamura, Akiko [Chile Observatory, National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Oshima, Tai [Nobeyama Radio Observatory, National Astronomical Observatory of Japan, Minamimaki, Minamisaku, Nagano 384-1305 (Japan); Scott, Kimberly S. [North American ALMA Science Center, National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Austermann, Jason E. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States); Tosaki, Tomoka [Joetsu University of Education, Joetsu, Niigata 943-8512 (Japan); Onishi, Toshikazu [Department of Physical Science, Osaka Prefecture University, Gakuen 1-1, Sakai, 599-8531 Osaka (Japan); Fukui, Yasuo [Department of Astrophysics, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan); Matsuo, Hiroshi [Advanced Technology Center, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Aretxaga, Itziar [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), 72000 Puebla (Mexico); and others

2013-09-10

We report the discovery of a new ultra-bright submillimeter galaxy (SMG) behind the Small Magellanic Cloud (SMC). This SMG is detected as a 43.3 {+-} 8.4 mJy point source (MM J01071-7302, hereafter MMJ0107) in the 1.1 mm continuum survey of the SMC by AzTEC on the ASTE telescope. MMJ0107 is also detected in the radio (843 MHz), Herschel/SPIRE, Spitzer MIPS 24 {mu}m, all IRAC bands, Wide-field Infrared Survey Explorer, and near-infrared (J, H, K{sub S} ). We find an optical (U, B, V) source, which might be the lensing object, at a distance of 1.''4 from near-infrared and IRAC sources. Photometric redshift estimates for the SMG using representative spectral energy distribution templates show the redshifts of 1.4-3.9. We estimate total far-infrared luminosity of (0.3-2.2) Multiplication-Sign 10{sup 14} {mu}{sup -1} L{sub Sun} and a star formation rate of 5600-39, 000 {mu}{sup -1} M{sub Sun} yr{sup -1}, where {mu} is the gravitational magnification factor. This apparent extreme star formation activity is likely explained by a highly magnified gravitational lens system.

High-brightness electron source driven by laser

International Nuclear Information System (INIS)

Zhao Kui; Geng Rongli; Wang Lifang

1996-01-01

A DC high-brightness laser driven by photo emissive electron gun is being developed at Beijing University, in order to produce 50∼100 ps electron bunches of high quality. The gun consists of a photocathode preparation chamber and a DC acceleration cavity. Different ways of fabricating photocathode, such as chemical vapor deposition, ion beam implantation and ion beam enhanced deposition, can be adopted. The acceleration gap is designed with the aid of simulation codes EGUN and POISSON. 100 kV DC high voltage is fed to the anode through a careful designed ceramic insulator. The laser system is a mode locked Nd-YAG oscillator proceeded by an amplifier at 10 Hz repetition rate, which can deliver three different wavelength (1064/532/266 nm). The combination of a superconducting cavity with the photocathode preparation chamber is discussed

Linear feature detection algorithm for astronomical surveys - II. Defocusing effects on meteor tracks

Science.gov (United States)

Bektešević, Dino; Vinković, Dejan; Rasmussen, Andrew; Ivezić, Željko

2018-03-01

Given the current limited knowledge of meteor plasma micro-physics and its interaction with the surrounding atmosphere and ionosphere, meteors are a highly interesting observational target for high-resolution wide-field astronomical surveys. Such surveys are capable of resolving the physical size of meteor plasma heads, but they produce large volumes of images that need to be automatically inspected for possible existence of long linear features produced by meteors. Here, we show how big aperture sky survey telescopes detect meteors as defocused tracks with a central brightness depression. We derive an analytic expression for a defocused point source meteor track and use it to calculate brightness profiles of meteors modelled as uniform brightness discs. We apply our modelling to meteor images as seen by the Sloan Digital Sky Survey and Large Synoptic Survey Telescope telescopes. The expression is validated by Monte Carlo ray-tracing simulations of photons travelling through the atmosphere and the Large Synoptic Survey Telescope telescope optics. We show that estimates of the meteor distance and size can be extracted from the measured full width at half-maximum and the strength of the central dip in the observed brightness profile. However, this extraction becomes difficult when the defocused meteor track is distorted by the atmospheric seeing or contaminated by a long-lasting glowing meteor trail. The full width at half-maximum of satellite tracks is distinctly narrower than meteor values, which enables removal of a possible confusion between satellites and meteors.

Plasmonic EIT-like switching in bright-dark-bright plasmon resonators.

Science.gov (United States)

Chen, Junxue; Wang, Pei; Chen, Chuncong; Lu, Yonghua; Ming, Hai; Zhan, Qiwen

2011-03-28

In this paper we report the study of the electromagnetically induced transparency (EIT)-like transmission in the bright-dark-bright plasmon resonators. It is demonstrated that the interferences between the dark plasmons excited by two bright plasmon resonators can be controlled by the incident light polarization. The constructive interference strengthens the coupling between the bright and dark resonators, leading to a more prominent EIT-like transparency window of the metamaterial. In contrary, destructive interference suppresses the coupling between the bright and dark resonators, destroying the interference pathway that forms the EIT-like transmission. Based on this observation, the plasmonic EIT switching can be realized by changing the polarization of incident light. This phenomenon may find applications in optical switching and plasmon-based information processing.

Mid infra-red hyper-spectral imaging with bright super continuum source and fast acousto-optic tuneable filter for cytological applications

International Nuclear Information System (INIS)

Farries, Mark; Ward, Jon; Valle, Stefano; Stephens, Gary; Moselund, Peter; Van der Zanden, Koen; Napier, Bruce

2015-01-01

Mid-IR imaging spectroscopy has the potential to offer an effective tool for early cancer diagnosis. Current development of bright super-continuum sources, narrow band acousto-optic tunable filters and fast cameras have made feasible a system that can be used for fast diagnosis of cancer in vivo at point of care. The performance of a proto system that has been developed under the Minerva project is described. (paper)

CHARACTERIZING THE POPULATION OF BRIGHT INFRARED SOURCES IN THE SMALL MAGELLANIC CLOUD

Energy Technology Data Exchange (ETDEWEB)

Kraemer, K. E. [Institute for Scientific Research, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467 (United States); Sloan, G. C. [Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY 14853-6801 (United States); Wood, P. R. [Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston Creek ACT 2611 (Australia); Jones, O. C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Egan, M. P., E-mail: kathleen.kraemer@bc.edu, E-mail: sloan@astro.cornell.edu, E-mail: wood@mso.anu.edu.au, E-mail: michael.p.egan@nga.mil [National Geospatial Intelligence Agency, 7500 GEOINT Drive, Springfield, VA 22150 (United States)

2017-01-10

We have used the Infrared Spectrograph (IRS) on the Spitzer Space Telescope to observe stars in the Small Magellanic Cloud (SMC) selected from the Point Source Catalog of the Midcourse Space Experiment (MSX). We concentrate on the dust properties of the oxygen-rich evolved stars. The dust composition has smaller contributions from alumina compared to the Galaxy. This difference may arise from the lower metallicity in the SMC, but it could be a selection effect, as the SMC sample includes more stars that are brighter and thus more massive. The distribution of the SMC stars along the silicate sequence looks more like the Galactic sample of red supergiants than asymptotic giant branch stars (AGBs). While many of the SMC stars are definitively on the AGB, several also show evidence of hot bottom burning. Three of the supergiants show PAH emission at 11.3 μ m. Two other sources show mixed chemistry, with both carbon-rich and oxygen-rich spectral features. One, MSX SMC 134, may be the first confirmed silicate/carbon star in the SMC. The other, MSX SMC 049, is a candidate post-AGB star. MSX SMC 145, previously considered a candidate OH/IR star, is actually an AGB star with a background galaxy at z  = 0.16 along the same line of sight. We consider the overall characteristics of all the MSX sources, the most infrared-bright objects in the SMC, in light of the higher sensitivity and resolution of Spitzer , and compare them with the object types expected from the original selection criteria. This population represents what will be seen in more distant galaxies by the upcoming James Webb Space Telescope ( JWST ). Color–color diagrams generated from the IRS spectra and the mid-infrared filters on JWST show how one can separate evolved stars from young stellar objects (YSOs) and distinguish among different classes of YSOs.

CHARACTERIZING THE POPULATION OF BRIGHT INFRARED SOURCES IN THE SMALL MAGELLANIC CLOUD

International Nuclear Information System (INIS)

Kraemer, K. E.; Sloan, G. C.; Wood, P. R.; Jones, O. C.; Egan, M. P.

2017-01-01

We have used the Infrared Spectrograph (IRS) on the Spitzer Space Telescope to observe stars in the Small Magellanic Cloud (SMC) selected from the Point Source Catalog of the Midcourse Space Experiment (MSX). We concentrate on the dust properties of the oxygen-rich evolved stars. The dust composition has smaller contributions from alumina compared to the Galaxy. This difference may arise from the lower metallicity in the SMC, but it could be a selection effect, as the SMC sample includes more stars that are brighter and thus more massive. The distribution of the SMC stars along the silicate sequence looks more like the Galactic sample of red supergiants than asymptotic giant branch stars (AGBs). While many of the SMC stars are definitively on the AGB, several also show evidence of hot bottom burning. Three of the supergiants show PAH emission at 11.3 μ m. Two other sources show mixed chemistry, with both carbon-rich and oxygen-rich spectral features. One, MSX SMC 134, may be the first confirmed silicate/carbon star in the SMC. The other, MSX SMC 049, is a candidate post-AGB star. MSX SMC 145, previously considered a candidate OH/IR star, is actually an AGB star with a background galaxy at z  = 0.16 along the same line of sight. We consider the overall characteristics of all the MSX sources, the most infrared-bright objects in the SMC, in light of the higher sensitivity and resolution of Spitzer , and compare them with the object types expected from the original selection criteria. This population represents what will be seen in more distant galaxies by the upcoming James Webb Space Telescope ( JWST ). Color–color diagrams generated from the IRS spectra and the mid-infrared filters on JWST show how one can separate evolved stars from young stellar objects (YSOs) and distinguish among different classes of YSOs.

Finding X-ray counterparts for unidentified sources in the 105 months BAT survey - 1

Science.gov (United States)

Stephen, J. B.; Bassani, L.; Malizia, A.; Masetti, N.; Ubertini, P.

2018-02-01

We provide X-ray counterparts for the unidentified Swift/BAT sources listed in the 105 month catalogue (Oh et al. 2018, ApJS in press). These associations were found by cross-correlating the list of U1,U2 and U3 sources with the ROSAT Bright (RASSBSC, Voges et al. 1999, A & A, 349, 389) and the XMM-Newton Slew (XMMSlew, Saxton et al. 2008, A & A, 480, 611) catalogues.

The Physics and Applications of High Brightness Electron Beams

Science.gov (United States)

Palumbo, Luigi; Rosenzweig, J.; Serafini, Luca

2007-09-01

Plenary sessions. RF deflector based sub-Ps beam diagnostics: application to FEL and advanced accelerators / D. Alesini. Production of fermtosecond pulses and micron beam spots for high brightness electron beam applications / S.G. Anderson ... [et al.]. Wakefields of sub-picosecond electron bunches / K.L.F. Bane. Diamond secondary emitter / I. Ben-Zvi ... [et al.]. Parametric optimization for an X-ray free electron laser with a laser wiggler / R. Bonifacio, N. Piovella and M.M. Cola. Needle cathodes for high-brightness beams / C.H. Boulware ... [et al.]. Non linear evolution of short pulses in FEL cascaded undulators and the FEL harmonic cascade / L. Giannessi and P. Musumeci. High brightness laser induced multi-meV electron/proton sources / D. Giulietti ... [et al.]. Emittance limitation of a conditioned beam in a strong focusing FEL undulator / Z. Huang, G. Stupakov and S. Reiche. Scaled models: space-charge dominated electron storage rings / R.A. Kishek ... [et al.]. High brightness beam applications: energy recovered linacs / G.A. Krafft. Maximizing brightness in photoinjectors / C. Limborg-Deprey and H. Tomizawa. Ultracold electron sources / O.J. Luiten ... [et al.]. Scaling laws of structure-based optical accelerators / A. Mizrahi, V. Karagodsky and L. Schächter. High brightness beams-applications to free-electron lasers / S. Reiche. Conception of photo-injectors for the CTF3 experiment / R. Roux. Superconducting RF photoinjectors: an overview / J. Sekutowicz. Status and perspectives of photo injector developments for high brightness beams / F. Stephan. Results from the UCLA/FNLP underdense plasma lens experiment / M.C. Thompson ... [et al.]. Medical application of multi-beam compton scattering monochromatic tunable hard X-ray source / M. Uesaka ... [et al.]. Design of a 2 kA, 30 fs RF-photoinjector for waterbag compression / S.B. Van Der Geer, O.J. Luiten and M.J. De Loos. Proposal for a high-brightness pulsed electron source / M. Zolotorev ... [et al

Discussion of high brightness rf linear accelerators

International Nuclear Information System (INIS)

Jameson, R.A.

1987-01-01

The fundamental aspects of high-brightness rf linacs are outlined, showing the breadth and complexity of the technology and indicating that synergism with advancements in other areas is important. Areas of technology reviewed include ion sources, injectors, rf accelerator structures, beam dynamics, rf power, and automatic control

Evolutionary tracks of extended radio sources

International Nuclear Information System (INIS)

Baldwin, J.E.

1982-01-01

We know almost nothing about the evolutionary tracks of extragalactic radio sources but those tracks are, however, strongly constrained by the distribution of sources in the radio luminosity, P, overall physical size, D, diagram. The P-D diagram for the 3CR 166 source sample of Jenkins et al. (1977) is presented with later additions. Most of the sources are identified and have known redshifts. Because of doubts about the completeness of the sample in this region, the author has made searches in the 6C 151MHz survey for sources with specific surface brightnesses. The numbers found to a limiting flux density of 1-2 Jy suggest that there is no serious underestimate of the numbers in 166 source sample. (Auth.)

An ASCA Survey of GeV Sources

Science.gov (United States)

Roberts, M. S. E.; Romani, R. W.; Kawai, N.

1999-04-01

We present an ASCA survey of GeV selected EGRET sources with E>1 GeV gamma -ray photon flux >5.0 x 10(-8) cm(-2) s(-1) . A combination of archival and new data covers ~ 75% of the sky contained within the 95% confidence position contours of these sources, and additional data obtained during the current observing cycle will increase this coverage to ~ 90%. We start with flat-fielded 2-10 keV images from the GIS data, and fit power-law spectra to potential counterparts. SIS, ROSAT, and Einstein data are used to confirm source detections and extend survey coverage. We then use the X-ray sources to identify radio counterparts in continuum survey data. Of the 26 GeV sources above our flux threshhold (Lamb and Macomb, 1997), 3 of the 4 at high galactic latitudes (bga 10(deg) ) are known blazars, while 5 of the low latitude sources are young pulsars. Of the remaining sources, 5 are plausibly associated with known young pulsars and/or plerionic SNR, one is at the Galactic center, and one may be associated with LSI+61 303. We focus here on the remaining 11 sources. By comparison with the known radio and X-ray properties of blazars and pulsars, we can identify potential members of these source classes, and potential new classes of gamma -ray emitters. We also estimate source luminosities using distances inferred from nearby tracers of star formation (Yadigaroglu and Romani, 1997). Data from several fields are consistent with these sources being synchrotron nebulae surrounding radio-quiet `Geminga-like' pulsars. These data provide incentives for further searches for pulsations at high energies and in the radio. In other fields identification is more problematic. We compare our results to models of the relative beaming fractions inferred from the radio and gamma -ray ray pulse shapes. The fraction of `pulsar candidate' detections is shown to provide useful constraints on pulsar luminosity evolution and beaming statistics.

Land Streamer Surveying Using Multiple Sources

KAUST Repository

Mahmoud, Sherif

2014-12-11

Various examples are provided for land streamer seismic surveying using multiple sources. In one example, among others, a method includes disposing a land streamer in-line with first and second shot sources. The first shot source is at a first source location adjacent to a proximal end of the land streamer and the second shot source is at a second source location separated by a fixed length corresponding to a length of the land streamer. Shot gathers can be obtained when the shot sources are fired. In another example, a system includes a land streamer including a plurality of receivers, a first shot source located adjacent to the proximal end of the land streamer, and a second shot source located in-line with the land streamer and the first shot source. The second shot source is separated from the first shot source by a fixed overall length corresponding to the land streamer.

The surface brightness of 1550 galaxies in Fornax: automated galaxy surface photometry: Pt. 2

International Nuclear Information System (INIS)

Phillipps, S.; Disney, M.J.; Kibblewhite, E.J.; Cawson, M.G.M.

1987-01-01

A survey of a complete sample of galaxies in the region of the Fornax cluster is presented. Measurements with the Automatic Plate Measuring machine are used to derive the observed distribution of galaxy surface brightness for 1550 objects. Corrections for surface brightness dependent selection effects are then made in order to estimate the true distribution. It is found that the sample (with 16.6 ≤ Msub(APM) ≤ 19.1) is divided into two distinct populations. The 'normal' galaxies with extrapolated central surface brightness Ssub(x) ≤ 22.5 Bμ form a uniformly distributed background of field galaxies. Low surface brightness galaxies (Ssub(x) ≥ 22.5 Bμ), on the other hand, are strongly clumped about the cluster centre. There appear to be few low surface brightness field galaxies. (author)

Finding X-ray counterparts for unidentified sources in the 105 months BAT survey - 2

Science.gov (United States)

Stephen, J. B.; Bassani, L.; Malizia, A.; Masetti, N.; Ubertini, P.

2018-02-01

We provide X-ray counterparts for unidentified Swift/BAT sources in the 105 month catalogue (Oh et al. 2018, ApJS in press). They were found by cross-correlating the list of U1,U2 and U3 sources with the ROSAT Bright (RASSBSC, Voges et al. 1999, A & A, 349, 389) and XMM-Newton Slew (XMMSlew, Saxton et al. 2008, A & A, 480, 611) catalogues and optically identified as reported in Atel #11340.

Adoption of open source digital library software packages: a survey

OpenAIRE

Jose, Sanjo

2007-01-01

Open source digital library packages are gaining popularity nowadays. To build a digital library under economical conditions open source software is preferable. This paper tries to identify the extent of adoption of open source digital library software packages in various organizations through an online survey. It lays down the findings from the survey.

SURVEY-Various Flooding Sources in Natroa County, WY

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Survey data includes spatial datasets and data tables necessary to digitally represent data collected in the survey phase of the study. (Source: FEMA Guidelines and...

SURVEY-Various Flooding Sources in Sevier County, UT

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Survey data includes spatial datasets and data tables necessary to digitally represent data collected in the survey phase of the study. (Source: FEMA Guidelines and...

Survey of residential magnetic field sources interim report

International Nuclear Information System (INIS)

Dunlap, J.H.; Zaffanella, L.E.; Johnson, G.B.

1993-01-01

The Electric Power Research Institute (EPRI) has conducted a nationwide survey to collect engineering data on the sources and the levels of power frequency magnetic fields that exist in residences. The survey involves measurements at approximately 1,000 residences randomly selected in the service area of 25 utilities. The information in this paper contains data from approximately 700 homes measured. The goals of the survey are to identify all significant sources of 60 Hz magnetic field in residences, estimate with sufficient accuracy the fraction of residences in which magnetic field exceeds any specified level, determine the relation between field and source parameters, and characterize spatial and temporal variations and harmonic content of the field. The data obtained relate to the level of the 60 Hz magnetic field and the source of the field, and not to personal exposure to magnetic fields, which is likely to be different due to the activity patterns of people. Magnetic fields from electrical appliances were measured intentionally away from the influence of appliance fields, which is limited to an area close to the appliance. Special measuring techniques were used to determine how the field varied within the living space of the house and over a twenty-four hour period. The field from each source is expressed in terms of how frequently a given field level is exceeded. The following sources of 60 Hz residential magnetic fields were identified: electrical appliances, grounding system of residences, overhead and underground power distribution lines, overhead power transmission lines, ground connections at electrical subpanels, and special wiring situations. Data from the appliance measurements is in a report published by EPRI, open-quotes Survey of Residential Magnetic Field Sources - Interim Reportclose quotes, TR-100194, which also provides much more detailed information on all subjects outlined in this paper

Enhancing the brightness of electrically driven single-photon sources using color centers in silicon carbide

Science.gov (United States)

Khramtsov, Igor A.; Vyshnevyy, Andrey A.; Fedyanin, Dmitry Yu.

2018-03-01

Practical applications of quantum information technologies exploiting the quantum nature of light require efficient and bright true single-photon sources which operate under ambient conditions. Currently, point defects in the crystal lattice of diamond known as color centers have taken the lead in the race for the most promising quantum system for practical non-classical light sources. This work is focused on a different quantum optoelectronic material, namely a color center in silicon carbide, and reveals the physics behind the process of single-photon emission from color centers in SiC under electrical pumping. We show that color centers in silicon carbide can be far superior to any other quantum light emitter under electrical control at room temperature. Using a comprehensive theoretical approach and rigorous numerical simulations, we demonstrate that at room temperature, the photon emission rate from a p-i-n silicon carbide single-photon emitting diode can exceed 5 Gcounts/s, which is higher than what can be achieved with electrically driven color centers in diamond or epitaxial quantum dots. These findings lay the foundation for the development of practical photonic quantum devices which can be produced in a well-developed CMOS compatible process flow.

Optical observations of LIGO source GW 170817 by the Antarctic Survey Telescopes at Dome A, Antarctica

Science.gov (United States)

Hu, Lei; Wu, Xuefeng; Andreoni, Igor; Ashley, Michael C. B.; Cooke, Jeff; Cui, Xiangqun; Du, Fujia; Dai, Zigao; Gu, Bozhong; Hu, Yi; Lu, Haiping; Li, Xiaoyan; Li, Zhengyang; Liang, Ensi; Liu, Liangduan; Ma, Bin; Shang, Zhaohui; Sun, Tianrui; Suntzeff, N. B.; Tao, Charling; Udden, Syed A.; Wang, Lifan; Wang, Xiaofeng; Wen, Haikun; Xiao, Di; Su, Jin; Yang, Ji; Yang, Shihai; Yuan, Xiangyan; Zhou, Hongyan; Zhang, Hui; Zhou, Jilin; Zhu, Zonghong

2017-10-01

The LIGO detection of gravitational waves (GW) from merging black holes in 2015 marked the beginning of a new era in observational astronomy. The detection of an electromagnetic signal from a GW source is the critical next step to explore in detail the physics involved. The Antarctic Survey Telescopes (AST3), located at Dome A, Antarctica, is uniquely situated for rapid response time-domain astronomy with its continuous night-time coverage during the austral winter. We report optical observations of the GW source (GW 170817) in the nearby galaxy NGC 4993 using AST3. The data show a rapidly fading transient at around 1 day after the GW trigger, with the i-band magnitude declining from 17.23±0.13 magnitude to 17.72±0.09 magnitude in ˜ 0.8 hour. The brightness and time evolution of the optical transient associated with GW 170817 are broadly consistent with the predictions of models involving merging binary neutron stars. We infer from our data that the merging process ejected about ˜ 10^{-2} solar mass of radioactive material at a speed of up to 30% the speed of light.

Bright Single-Photon Sources Based on Anti-Reflection Coated Deterministic Quantum Dot Microlenses

Directory of Open Access Journals (Sweden)

Peter Schnauber

2015-12-01

Full Text Available We report on enhancing the photon-extraction efficiency (PEE of deterministic quantum dot (QD microlenses via anti-reflection (AR coating. The AR-coating deposited on top of the curved microlens surface is composed of a thin layer of Ta2O5, and is found to effectively reduce back-reflection of light at the semiconductor-vacuum interface. A statistical analysis of spectroscopic data reveals, that the AR-coating improves the light out-coupling of respective microlenses by a factor of 1.57 ± 0.71, in quantitative agreement with numerical calculations. Taking the enhancement factor into account, we predict improved out-coupling of light with a PEE of up to 50%. The quantum nature of emission from QDs integrated into AR-coated microlenses is demonstrated via photon auto-correlation measurements revealing strong suppression of two-photon emission events with g(2(0 = 0.05 ± 0.02. As such, these bright non-classical light sources are highly attractive with respect to applications in the field of quantum cryptography.

SPIDERS: selection of spectroscopic targets using AGN candidates detected in all-sky X-ray surveys

Science.gov (United States)

Dwelly, T.; Salvato, M.; Merloni, A.; Brusa, M.; Buchner, J.; Anderson, S. F.; Boller, Th.; Brandt, W. N.; Budavári, T.; Clerc, N.; Coffey, D.; Del Moro, A.; Georgakakis, A.; Green, P. J.; Jin, C.; Menzel, M.-L.; Myers, A. D.; Nandra, K.; Nichol, R. C.; Ridl, J.; Schwope, A. D.; Simm, T.

2017-07-01

SPIDERS (SPectroscopic IDentification of eROSITA Sources) is a Sloan Digital Sky Survey IV (SDSS-IV) survey running in parallel to the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) cosmology project. SPIDERS will obtain optical spectroscopy for large numbers of X-ray-selected active galactic nuclei (AGN) and galaxy cluster members detected in wide-area eROSITA, XMM-Newton and ROSAT surveys. We describe the methods used to choose spectroscopic targets for two sub-programmes of SPIDERS X-ray selected AGN candidates detected in the ROSAT All Sky and the XMM-Newton Slew surveys. We have exploited a Bayesian cross-matching algorithm, guided by priors based on mid-IR colour-magnitude information from the Wide-field Infrared Survey Explorer survey, to select the most probable optical counterpart to each X-ray detection. We empirically demonstrate the high fidelity of our counterpart selection method using a reference sample of bright well-localized X-ray sources collated from XMM-Newton, Chandra and Swift-XRT serendipitous catalogues, and also by examining blank-sky locations. We describe the down-selection steps which resulted in the final set of SPIDERS-AGN targets put forward for spectroscopy within the eBOSS/TDSS/SPIDERS survey, and present catalogues of these targets. We also present catalogues of ˜12 000 ROSAT and ˜1500 XMM-Newton Slew survey sources that have existing optical spectroscopy from SDSS-DR12, including the results of our visual inspections. On completion of the SPIDERS programme, we expect to have collected homogeneous spectroscopic redshift information over a footprint of ˜7500 deg2 for >85 per cent of the ROSAT and XMM-Newton Slew survey sources having optical counterparts in the magnitude range 17 < r < 22.5, producing a large and highly complete sample of bright X-ray-selected AGN suitable for statistical studies of AGN evolution and clustering.

Calibrate the aerial surveying instrument by the limited surface source and the single point source that replace the unlimited surface source

CERN Document Server

Lu Cun Heng

1999-01-01

It is described that the calculating formula and surveying result is found on the basis of the stacking principle of gamma ray and the feature of hexagonal surface source when the limited surface source replaces the unlimited surface source to calibrate the aerial survey instrument on the ground, and that it is found in the light of the exchanged principle of the gamma ray when the single point source replaces the unlimited surface source to calibrate aerial surveying instrument in the air. Meanwhile through the theoretical analysis, the receiving rate of the crystal bottom and side surfaces is calculated when aerial surveying instrument receives gamma ray. The mathematical expression of the gamma ray decaying following height according to the Jinge function regularity is got. According to this regularity, the absorbing coefficient that air absorbs the gamma ray and the detective efficiency coefficient of the crystal is calculated based on the ground and air measuring value of the bottom surface receiving cou...

The ASAS-SN bright supernova catalogue - III. 2016

Science.gov (United States)

Holoien, T. W.-S.; Brown, J. S.; Stanek, K. Z.; Kochanek, C. S.; Shappee, B. J.; Prieto, J. L.; Dong, Subo; Brimacombe, J.; Bishop, D. W.; Bose, S.; Beacom, J. F.; Bersier, D.; Chen, Ping; Chomiuk, L.; Falco, E.; Godoy-Rivera, D.; Morrell, N.; Pojmanski, G.; Shields, J. V.; Strader, J.; Stritzinger, M. D.; Thompson, Todd A.; Woźniak, P. R.; Bock, G.; Cacella, P.; Conseil, E.; Cruz, I.; Fernandez, J. M.; Kiyota, S.; Koff, R. A.; Krannich, G.; Marples, P.; Masi, G.; Monard, L. A. G.; Nicholls, B.; Nicolas, J.; Post, R. S.; Stone, G.; Wiethoff, W. S.

2017-11-01

This catalogue summarizes information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (mpeak ≤ 17), spectroscopically confirmed supernovae discovered in 2016. We then gather the near-infrared through ultraviolet magnitudes of all host galaxies and the offsets of the supernovae from the centres of their hosts from public data bases. We illustrate the results using a sample that now totals 668 supernovae discovered since 2014 May 1, including the supernovae from our previous catalogues, with type distributions closely matching those of the ideal magnitude limited sample from Li et al. This is the third of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team.

Night-sky brightness monitoring in Hong Kong: a city-wide light pollution assessment.

Science.gov (United States)

Pun, Chun Shing Jason; So, Chu Wing

2012-04-01

Results of the first comprehensive light pollution survey in Hong Kong are presented. The night-sky brightness was measured and monitored around the city using a portable light-sensing device called the Sky Quality Meter over a 15-month period beginning in March 2008. A total of 1,957 data sets were taken at 199 distinct locations, including urban and rural sites covering all 18 Administrative Districts of Hong Kong. The survey shows that the environmental light pollution problem in Hong Kong is severe-the urban night skies (sky brightness at 15.0 mag arcsec(- 2)) are on average ~ 100 times brighter than at the darkest rural sites (20.1 mag arcsec(- 2)), indicating that the high lighting densities in the densely populated residential and commercial areas lead to light pollution. In the worst polluted urban location studied, the night-sky at 13.2 mag arcsec(- 2) can be over 500 times brighter than the darkest sites in Hong Kong. The observed night-sky brightness is found to be affected by human factors such as land utilization and population density of the observation sites, together with meteorological and/or environmental factors. Moreover, earlier night skies (at 9:30 p.m. local time) are generally brighter than later time (at 11:30 p.m.), which can be attributed to some public and commercial lightings being turned off later at night. On the other hand, no concrete relationship between the observed sky brightness and air pollutant concentrations could be established with the limited survey sampling. Results from this survey will serve as an important database for the public to assess whether new rules and regulations are necessary to control the use of outdoor lightings in Hong Kong.

SIMULTANEOUS MULTI-BAND DETECTION OF LOW SURFACE BRIGHTNESS GALAXIES WITH MARKOVIAN MODELING

International Nuclear Information System (INIS)

Vollmer, B.; Bonnarel, F.; Louys, M.; Perret, B.; Petremand, M.; Lavigne, F.; Collet, Ch.; Van Driel, W.; Sabatini, S.; MacArthur, L. A.

2013-01-01

We present to the astronomical community an algorithm for the detection of low surface brightness (LSB) galaxies in images, called MARSIAA (MARkovian Software for Image Analysis in Astronomy), which is based on multi-scale Markovian modeling. MARSIAA can be applied simultaneously to different bands. It segments an image into a user-defined number of classes, according to their surface brightness and surroundings—typically, one or two classes contain the LSB structures. We have developed an algorithm, called DetectLSB, which allows the efficient identification of LSB galaxies from among the candidate sources selected by MARSIAA. The application of the method to two and three bands simultaneously was tested on simulated images. Based on our tests, we are confident that we can detect LSB galaxies down to a central surface brightness level of only 1.5 times the standard deviation from the mean pixel value in the image background. To assess the robustness of our method, the method was applied to a set of 18 B- and I-band images (covering 1.3 deg 2 in total) of the Virgo Cluster to which Sabatini et al. previously applied a matched-filter dwarf LSB galaxy search algorithm. We have detected all 20 objects from the Sabatini et al. catalog which we could classify by eye as bona fide LSB galaxies. Our method has also detected four additional Virgo Cluster LSB galaxy candidates undetected by Sabatini et al. To further assess the completeness of the results of our method, both MARSIAA, SExtractor, and DetectLSB were applied to search for (1) mock Virgo LSB galaxies inserted into a set of deep Next Generation Virgo Survey (NGVS) gri-band subimages and (2) Virgo LSB galaxies identified by eye in a full set of NGVS square degree gri images. MARSIAA/DetectLSB recovered ∼20% more mock LSB galaxies and ∼40% more LSB galaxies identified by eye than SExtractor/DetectLSB. With a 90% fraction of false positives from an entirely unsupervised pipeline, a completeness of 90% is

Circadian Phase-Shifting Effects of Bright Light, Exercise, and Bright Light + Exercise.

Science.gov (United States)

Youngstedt, Shawn D; Kline, Christopher E; Elliott, Jeffrey A; Zielinski, Mark R; Devlin, Tina M; Moore, Teresa A

2016-02-26

Limited research has compared the circadian phase-shifting effects of bright light and exercise and additive effects of these stimuli. The aim of this study was to compare the phase-delaying effects of late night bright light, late night exercise, and late evening bright light followed by early morning exercise. In a within-subjects, counterbalanced design, 6 young adults completed each of three 2.5-day protocols. Participants followed a 3-h ultra-short sleep-wake cycle, involving wakefulness in dim light for 2h, followed by attempted sleep in darkness for 1 h, repeated throughout each protocol. On night 2 of each protocol, participants received either (1) bright light alone (5,000 lux) from 2210-2340 h, (2) treadmill exercise alone from 2210-2340 h, or (3) bright light (2210-2340 h) followed by exercise from 0410-0540 h. Urine was collected every 90 min. Shifts in the 6-sulphatoxymelatonin (aMT6s) cosine acrophase from baseline to post-treatment were compared between treatments. Analyses revealed a significant additive phase-delaying effect of bright light + exercise (80.8 ± 11.6 [SD] min) compared with exercise alone (47.3 ± 21.6 min), and a similar phase delay following bright light alone (56.6 ± 15.2 min) and exercise alone administered for the same duration and at the same time of night. Thus, the data suggest that late night bright light followed by early morning exercise can have an additive circadian phase-shifting effect.

Bright Stuff on Ceres = Sulfates and Carbonates on CI Chondrites

Science.gov (United States)

Zolensky, Michael; Chan, Queenie H. S.; Gounelle, Matthieu; Fries, Marc

2016-01-01

Recent reports of the DAWN spacecraft's observations of the surface of Ceres indicate that there are bright areas, which can be explained by large amounts of the Mg sulfate hexahydrate (MgSO4•6(H2O)), although the identification appears tenuous. There are preliminary indications that water is being evolved from these bright areas, and some have inferred that these might be sites of contemporary hydro-volcanism. A heat source for such modern activity is not obvious, given the small size of Ceres, lack of any tidal forces from nearby giant planets, probable age and presumed bulk composition. We contend that observations of chondritic materials in the lab shed light on the nature of the bright spots on Ceres

Global Properties of M31's Stellar Halo from the SPLASH Survey. I. Surface Brightness Profile

Science.gov (United States)

Gilbert, Karoline M.; Guhathakurta, Puragra; Beaton, Rachael L.; Bullock, James; Geha, Marla C.; Kalirai, Jason S.; Kirby, Evan N.; Majewski, Steven R.; Ostheimer, James C.; Patterson, Richard J.; Tollerud, Erik J.; Tanaka, Mikito; Chiba, Masashi

2012-11-01

We present the surface brightness profile of M31's stellar halo out to a projected radius of 175 kpc. The surface brightness estimates are based on confirmed samples of M31 red giant branch stars derived from Keck/DEIMOS spectroscopic observations. A set of empirical spectroscopic and photometric M31 membership diagnostics is used to identify and reject foreground and background contaminants. This enables us to trace the stellar halo of M31 to larger projected distances and fainter surface brightnesses than previous photometric studies. The surface brightness profile of M31's halo follows a power law with index -2.2 ± 0.2 and extends to a projected distance of at least ~175 kpc (~2/3 of M31's virial radius), with no evidence of a downward break at large radii. The best-fit elliptical isophotes have b/a = 0.94 with the major axis of the halo aligned along the minor axis of M31's disk, consistent with a prolate halo, although the data are also consistent with M31's halo having spherical symmetry. The fact that tidal debris features are kinematically cold is used to identify substructure in the spectroscopic fields out to projected radii of 90 kpc and investigate the effect of this substructure on the surface brightness profile. The scatter in the surface brightness profile is reduced when kinematically identified tidal debris features in M31 are statistically subtracted; the remaining profile indicates that a comparatively diffuse stellar component to M31's stellar halo exists to large distances. Beyond 90 kpc, kinematically cold tidal debris features cannot be identified due to small number statistics; nevertheless, the significant field-to-field variation in surface brightness beyond 90 kpc suggests that the outermost region of M31's halo is also comprised to a significant degree of stars stripped from accreted objects. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California

Photocathodes inside superconducting cavities. Studies on the feasibility of a superconducting photoelectron source of high brightness. External report

International Nuclear Information System (INIS)

Michalke, A.

1992-01-01

We have done studies and experiments to explore the feasibility of a photoemission RF gun with a superconducting accelerator cavity. This concept promises to provide an electron beam of high brightness in continuous operation. It is thus of strong interest for a free-electron-laser or a linear collider based on a superconducting accelerator. In a first step we studied possible technical solutions for its components, especially the material of the photocathode and the geometrical shape of the cavity. Based on these considerations, we developed the complete design for a prototype electron source. The cathode material was chosen to be alkali antimonide. In spite of its sensitivity, it seems to be the best choice for a gun with high average current due to its high quantum efficiency. The cavity shape was at first a reentrant-type single cell of 500 MHz. It is now replaced by a more regular two-and-half cell shape, an independent half cell added for emittance correction. Its beam dynamics properties are investigated by numerical simulations; we estimated a beam brightness of about 5x10 11 A/(m.rad) 2 . But the mutual interactions between alkali antimonide photocathode and superconducting cavity must be investigated experimentally, because they are completely unkown. (orig.)

Bright spots among the world’s coral reefs

Science.gov (United States)

Cinner, Joshua E.; Huchery, Cindy; MacNeil, M. Aaron; Graham, Nicholas A. J.; McClanahan, Tim R.; Maina, Joseph; Maire, Eva; Kittinger, John N.; Hicks, Christina C.; Mora, Camilo; Allison, Edward H.; D'Agata, Stephanie; Hoey, Andrew; Feary, David A.; Crowder, Larry; Williams, Ivor D.; Kulbicki, Michel; Vigliola, Laurent; Wantiez, Laurent; Edgar, Graham; Stuart-Smith, Rick D.; Sandin, Stuart A.; Green, Alison L.; Hardt, Marah J.; Beger, Maria; Friedlander, Alan; Campbell, Stuart J.; Holmes, Katherine E.; Wilson, Shaun K.; Brokovich, Eran; Brooks, Andrew J.; Cruz-Motta, Juan J.; Booth, David J.; Chabanet, Pascale; Gough, Charlie; Tupper, Mark; Ferse, Sebastian C. A.; Sumaila, U. Rashid; Mouillot, David

2016-07-01

Ongoing declines in the structure and function of the world’s coral reefs require novel approaches to sustain these ecosystems and the millions of people who depend on them. A presently unexplored approach that draws on theory and practice in human health and rural development is to systematically identify and learn from the ‘outliers’—places where ecosystems are substantially better (‘bright spots’) or worse (‘dark spots’) than expected, given the environmental conditions and socioeconomic drivers they are exposed to. Here we compile data from more than 2,500 reefs worldwide and develop a Bayesian hierarchical model to generate expectations of how standing stocks of reef fish biomass are related to 18 socioeconomic drivers and environmental conditions. We identify 15 bright spots and 35 dark spots among our global survey of coral reefs, defined as sites that have biomass levels more than two standard deviations from expectations. Importantly, bright spots are not simply comprised of remote areas with low fishing pressure; they include localities where human populations and use of ecosystem resources is high, potentially providing insights into how communities have successfully confronted strong drivers of change. Conversely, dark spots are not necessarily the sites with the lowest absolute biomass and even include some remote, uninhabited locations often considered near pristine. We surveyed local experts about social, institutional, and environmental conditions at these sites to reveal that bright spots are characterized by strong sociocultural institutions such as customary taboos and marine tenure, high levels of local engagement in management, high dependence on marine resources, and beneficial environmental conditions such as deep-water refuges. Alternatively, dark spots are characterized by intensive capture and storage technology and a recent history of environmental shocks. Our results suggest that investments in strengthening fisheries

High-Energy Compton Scattering Light Sources

CERN Document Server

Hartemann, Fred V; Barty, C; Crane, John; Gibson, David J; Hartouni, E P; Tremaine, Aaron M

2005-01-01

No monochromatic, high-brightness, tunable light sources currently exist above 100 keV. Important applications that would benefit from such new hard x-ray sources include: nuclear resonance fluorescence spectroscopy, time-resolved positron annihilation spectroscopy, and MeV flash radiography. The peak brightness of Compton scattering light sources is derived for head-on collisions and found to scale with the electron beam brightness and the drive laser pulse energy. This gamma 2

Low surface brightness spiral galaxies

International Nuclear Information System (INIS)

Romanishin, W.

1980-01-01

This dissertation presents an observational overview of a sample of low surface brightness (LSB) spiral galaxies. The sample galaxies were chosen to have low surface brightness disks and indications of spiral structure visible on the Palomar Sky Survey. They are of sufficient angular size (diameter > 2.5 arcmin), to allow detailed surface photometry using Mayall 4-m prime focus plates. The major findings of this dissertation are: (1) The average disk central surface brightness of the LSB galaxies is 22.88 magnitude/arcsec 2 in the B passband. (2) From broadband color measurements of the old stellar population, we infer a low average stellar metallicity, on the order of 1/5 solar. (3) The spectra and optical colors of the HII regions in the LSB galaxies indicate a lack of hot ionizing stars compared to HII regions in other late-type galaxies. (4) The average surface mass density, measured within the radius containing half the total mass, is less than half that of a sample of normal late-type spirals. (5) The average LSB galaxy neutral hydrogen mass to blue luminosity ratio is about 0.6, significantly higher than in a sample of normal late-type galaxies. (6) We find no conclusive evidence of an abnormal mass-to-light ratio in the LSB galaxies. (7) Some of the LSB galaxies exhibit well-developed density wave patterns. (8) A very crude calculation shows the lower metallicity of the LSB galaxies compared with normal late-type spirals might be explained simply by the deficiency of massive stars in the LSB galaxies

UHE point source survey at Cygnus experiment

International Nuclear Information System (INIS)

Lu, X.; Yodh, G.B.; Alexandreas, D.E.; Allen, R.C.; Berley, D.; Biller, S.D.; Burman, R.L.; Cady, R.; Chang, C.Y.; Dingus, B.L.; Dion, G.M.; Ellsworth, R.W.; Gilra, M.K.; Goodman, J.A.; Haines, T.J.; Hoffman, C.M.; Kwok, P.; Lloyd-Evans, J.; Nagle, D.E.; Potter, M.E.; Sandberg, V.D.; Stark, M.J.; Talaga, R.L.; Vishwanath, P.R.; Zhang, W.

1991-01-01

A new method of searching for UHE point source has been developed. With a data sample of 150 million events, we have surveyed the sky for point sources over 3314 locations (1.4 degree <δ<70.4 degree). It was found that their distribution is consistent with a random fluctuation. In addition, fifty two known potential sources, including pulsars and binary x-ray sources, were studied. The source with the largest positive excess is the Crab Nebula. An excess of 2.5 sigma above the background is observed in a bin of 2.3 degree by 2.5 degree in declination and right ascension respectively

On the Feasibility of Very-Low-Density Pure Metal Foams as Bright High-Energy X-ray Sources

Science.gov (United States)

Colvin, Jeffrey; Felter, Thomas

2003-10-01

We have used the Busquet approximation (M. Busquet, Phys. Fluids B 5(11), 4191 (1993)) to explore calculationally what the possible x-ray conversion efficiencies into the K-band would be from irradiating very-low-density pure metal foams with tens of kilojoules of 1/3-micron laser light. We will discuss the advantages of pure metal foams as bright high-energy x-ray sources, and some results of this calculational study. We will also present our ideas for how to fabricate pure metal foams with densities of a few milligrams per cubic centimeter. This work was performed under the auspices of the US Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

Kiloamp high-brightness beams

International Nuclear Information System (INIS)

Caporaso, G.J.

1987-01-01

Brightness preservation of high-current relativistic electron beams under two different types of transport is discussed. Recent progress in improving the brightness of laser-guided beams in the Advanced Test Accelerator is reviewed. A strategy for the preservation of the brightness of space-charge-dominated beams in a solenoidal transport system is presented

Technological Challenges for High-Brightness Photo-Injectors

CERN Multimedia

Suberlucq, Guy

2004-01-01

Many applications, from linear colliders to free-electron lasers, passing through light sources and many other electron sources, require high brightness electron beams, usually produced by photo-injectors. Because certain parameters of these applications differ by several orders of magnitude, various solutions were implemented for the design and construction of the three main parts of the photo-injectors: lasers, photocathodes and guns. This paper summarizes the different requirements, how they lead to technological challenges and how R&D programs try to overcome these challenges. Some examples of state-of-the-art parts are presented.

Liquid-metal-jet anode electron-impact x-ray source

International Nuclear Information System (INIS)

Hemberg, O.; Otendal, M.; Hertz, H.M.

2003-01-01

We demonstrate an anode concept, based on a liquid-metal jet, for improved brightness in compact electron-impact x-ray sources. The source is demonstrated in a proof-of-principle experiment where a 50 keV, ∼100 W electron beam is focused on a 75 μm liquid-solder jet. The generated x-ray flux and brightness is quantitatively measured in the 7-50 keV spectral region and found to agree with theory. Compared to rotating-anode sources, whose brightness is limited by intrinsic thermal properties, the liquid-jet anode could potentially be scaled to achieve a brightness >100x higher than current state-of-the-art sources. Applications such as mammography, angiography, and diffraction would benefit from such a compact high-brightness source

A selective deficit in the appreciation and recognition of brightness: brightness agnosia?

Science.gov (United States)

Nijboer, Tanja C W; Nys, Gudrun M S; van der Smagt, Maarten J; de Haan, Edward H F

2009-01-01

We report a patient with extensive brain damage in the right hemisphere who demonstrated a severe impairment in the appreciation of brightness. Acuity, contrast sensitivity as well as luminance discrimination were normal, suggesting her brightness impairment is not a mere consequence of low-level sensory impairments. The patient was not able to indicate the darker or the lighter of two grey squares, even though she was able to see that they differed. In addition, she could not indicate whether the lights in a room were switched on or off, nor was she able to differentiate between normal greyscale images and inverted greyscale images. As the patient recognised objects, colours, and shapes correctly, the impairment is specific for brightness. As low-level, sensory processing is normal, this specific deficit in the recognition and appreciation of brightness appears to be of a higher, cognitive level, the level of semantic knowledge. This appears to be the first report of 'brightness agnosia'.

CHANDRA OBSERVATIONS OF 3C RADIO SOURCES WITH z < 0.3. II. COMPLETING THE SNAPSHOT SURVEY

Energy Technology Data Exchange (ETDEWEB)

Massaro, F. [SLAC National Laboratory and Kavli Institute for Particle Astrophysics and Cosmology, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Tremblay, G. R. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei Muenchen (Germany); Harris, D. E.; O' Dea, C. P. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Kharb, P.; Axon, D. [Department of Physics, Rochester Institute of Technology, Carlson Center for Imaging Science 76-3144, 84 Lomb Memorial Dr., Rochester, NY 14623 (United States); Balmaverde, B.; Capetti, A. [INAF-Osservatorio Astrofisico di Torino, Strada Osservatorio 20, I-10025 Pino Torinese (Italy); Baum, S. A. [Carlson Center for Imaging Science 76-3144, 84 Lomb Memorial Dr., Rochester, NY 14623 (United States); Chiaberge, M.; Macchetto, F. D.; Sparks, W. [Space Telescope Science Institute, 3700 San Martine Drive, Baltimore, MD 21218 (United States); Gilli, R. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Giovannini, G. [INAF-Istituto di Radioastronomia di Bologna, Via Gobetti 101, I-40129 Bologna (Italy); Grandi, P.; Torresi, E. [INAF-IASF-Istituto di Astrofisica Spaziale e fisica Cosmica di Bologna, Via P. Gobetti 101, I-40129 Bologna (Italy); Risaliti, G. [INAF-Osservatorio Astronomico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy)

2012-12-15

We report on the second round of Chandra observations of the 3C snapshot survey developed to observe the complete sample of 3C radio sources with z < 0.3 for 8 ks each. In the first paper, we illustrated the basic data reduction and analysis procedures performed for the 30 sources of the 3C sample observed during Chandra Cycle 9, while here we present the data for the remaining 27 sources observed during Cycle 12. We measured the X-ray intensity of the nuclei and of any radio hot spots and jet features with associated X-ray emission. X-ray fluxes in three energy bands, i.e., soft, medium, and hard, for all the sources analyzed are also reported. For the stronger nuclei, we also applied the standard spectral analysis, which provides the best-fit values of the X-ray spectral index and absorbing column density. In addition, a detailed analysis of bright X-ray nuclei that could be affected by pile-up has been performed. X-ray emission was detected for all the nuclei of the radio sources in our sample except for 3C 319. Among the current sample, there are two compact steep spectrum radio sources, two broad-line radio galaxies, and one wide angle tail radio galaxy, 3C 89, hosted in a cluster of galaxies clearly visible in our Chandra snapshot observation. In addition, we also detected soft X-ray emission arising from the galaxy cluster surrounding 3C 196.1. Finally, X-ray emission from hot spots has been found in three FR II radio sources and, in the case of 3C 459, we also report the detection of X-ray emission associated with the eastern radio lobe as well as X-ray emission cospatial with radio jets in 3C 29 and 3C 402.

BrightFocus Foundation

Science.gov (United States)

... About BrightFocus Foundation Featured Content BrightFocus: Investing in Science to Save Mind and Sight We're here to help. Explore ... recognition is very important. Monday, November 6, 2017 New Diagnosis? Managing a mind and sight disease is a journey. And you’ ...

X-ray-bright optically faint active galactic nuclei in the Subaru Hyper Suprime-Cam wide survey

Science.gov (United States)

Terashima, Yuichi; Suganuma, Makoto; Akiyama, Masayuki; Greene, Jenny E.; Kawaguchi, Toshihiro; Iwasawa, Kazushi; Nagao, Tohru; Noda, Hirofumi; Toba, Yoshiki; Ueda, Yoshihiro; Yamashita, Takuji

2018-01-01

We construct a sample of X-ray-bright optically faint active galactic nuclei by combining Subaru Hyper Suprime-Cam, XMM-Newton, and infrared source catalogs. Fifty-three X-ray sources satisfying i-band magnitude fainter than 23.5 mag and X-ray counts with the EPIC-PN detector larger than 70 are selected from 9.1 deg2, and their spectral energy distributions (SEDs) and X-ray spectra are analyzed. Forty-four objects with an X-ray to i-band flux ratio FX/Fi > 10 are classified as extreme X-ray-to-optical flux sources. Spectral energy distributions of 48 among 53 are represented by templates of type 2 AGNs or star-forming galaxies and show the optical signature of stellar emission from host galaxies in the source rest frame. Infrared/optical SEDs indicate a significant contribution of emission from dust to the infrared fluxes, and that the central AGN is dust obscured. The photometric redshifts determined from the SEDs are in the range of 0.6-2.5. The X-ray spectra are fitted by an absorbed power-law model, and the intrinsic absorption column densities are modest (best-fit log NH = 20.5-23.5 cm-2 in most cases). The absorption-corrected X-ray luminosities are in the range of 6 × 1042-2 × 1045 erg s-1. Twenty objects are classified as type 2 quasars based on X-ray luminsosity and NH. The optical faintness is explained by a combination of redshifts (mostly z > 1.0), strong dust extinction, and in part a large ratio of dust/gas.

Record high-average current from a high-brightness photoinjector

Energy Technology Data Exchange (ETDEWEB)

Dunham, Bruce; Barley, John; Bartnik, Adam; Bazarov, Ivan; Cultrera, Luca; Dobbins, John; Hoffstaetter, Georg; Johnson, Brent; Kaplan, Roger; Karkare, Siddharth; Kostroun, Vaclav; Li Yulin; Liepe, Matthias; Liu Xianghong; Loehl, Florian; Maxson, Jared; Quigley, Peter; Reilly, John; Rice, David; Sabol, Daniel [Cornell Laboratory for Accelerator-Based Sciences and Education, Cornell University, Ithaca, New York 14853 (United States); and others

2013-01-21

High-power, high-brightness electron beams are of interest for many applications, especially as drivers for free electron lasers and energy recovery linac light sources. For these particular applications, photoemission injectors are used in most cases, and the initial beam brightness from the injector sets a limit on the quality of the light generated at the end of the accelerator. At Cornell University, we have built such a high-power injector using a DC photoemission gun followed by a superconducting accelerating module. Recent results will be presented demonstrating record setting performance up to 65 mA average current with beam energies of 4-5 MeV.

Robust brightness enhancement across a luminance range of the glare illusion.

Science.gov (United States)

Tamura, Hideki; Nakauchi, Shigeki; Koida, Kowa

2016-01-01

The glare illusion refers to brightness enhancement and the perception of a self-luminous appearance that occurs when a central region is surrounded by a luminance gradient. The center region appears to be a light source, with its light dispersing into the surrounding region. If the luminous edge is critical for generating the illusion, modulating the perceived luminance of the image, and switching its appearance from luminous to nonluminous, would have a strong impact on lightness and brightness estimation. Here, we quantified the illusion in two ways, by assessing brightness enhancement and examining whether the center region appeared luminous. Thus, we could determine whether the two effects occurred jointly or independently. We examined a wide luminance range of center regions, from 0 to 200% relative to background. Brightness enhancement in the illusion was observed for a wide range of luminances (20% to 200% relative to background), while a luminous-white appearance was observed when the center region luminance was 145% of the background. These results exclude the possibility that brightness enhancement occurs because the stimuli appear self-luminous. We suggest that restoring the original image intensity precedes the perceptual process of lightness estimation.

SIMULTANEOUS MULTI-BAND DETECTION OF LOW SURFACE BRIGHTNESS GALAXIES WITH MARKOVIAN MODELING

Energy Technology Data Exchange (ETDEWEB)

Vollmer, B.; Bonnarel, F.; Louys, M. [CDS, Observatoire Astronomique, UMR 7550, 11 rue de l' universite, F-67000 Strasbourg (France); Perret, B.; Petremand, M.; Lavigne, F.; Collet, Ch. [LSIIT, Universite de Strasbourg, 7, Rue Rene Descartes, F-67084 Strasbourg (France); Van Driel, W. [GEPI, Observatoire de Paris, CNRS, Universite Paris Diderot, 5 place Jules Janssen, F-92190 Meudon (France); Sabatini, S. [INAF/IASF-Roma, via Fosso de Cavaliere 100, I-00133 Roma (Italy); MacArthur, L. A., E-mail: Bernd.Vollmer@astro.unistra.fr [Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria, BC V9E 2E7 (Canada)

2013-02-01

We present to the astronomical community an algorithm for the detection of low surface brightness (LSB) galaxies in images, called MARSIAA (MARkovian Software for Image Analysis in Astronomy), which is based on multi-scale Markovian modeling. MARSIAA can be applied simultaneously to different bands. It segments an image into a user-defined number of classes, according to their surface brightness and surroundings-typically, one or two classes contain the LSB structures. We have developed an algorithm, called DetectLSB, which allows the efficient identification of LSB galaxies from among the candidate sources selected by MARSIAA. The application of the method to two and three bands simultaneously was tested on simulated images. Based on our tests, we are confident that we can detect LSB galaxies down to a central surface brightness level of only 1.5 times the standard deviation from the mean pixel value in the image background. To assess the robustness of our method, the method was applied to a set of 18 B- and I-band images (covering 1.3 deg{sup 2} in total) of the Virgo Cluster to which Sabatini et al. previously applied a matched-filter dwarf LSB galaxy search algorithm. We have detected all 20 objects from the Sabatini et al. catalog which we could classify by eye as bona fide LSB galaxies. Our method has also detected four additional Virgo Cluster LSB galaxy candidates undetected by Sabatini et al. To further assess the completeness of the results of our method, both MARSIAA, SExtractor, and DetectLSB were applied to search for (1) mock Virgo LSB galaxies inserted into a set of deep Next Generation Virgo Survey (NGVS) gri-band subimages and (2) Virgo LSB galaxies identified by eye in a full set of NGVS square degree gri images. MARSIAA/DetectLSB recovered {approx}20% more mock LSB galaxies and {approx}40% more LSB galaxies identified by eye than SExtractor/DetectLSB. With a 90% fraction of false positives from an entirely unsupervised pipeline, a completeness of

Calibrate the aerial surveying instrument by the limited surface source and the single point source that replace the unlimited surface source

International Nuclear Information System (INIS)

Lu Cunheng

1999-01-01

It is described that the calculating formula and surveying result is found on the basis of the stacking principle of gamma ray and the feature of hexagonal surface source when the limited surface source replaces the unlimited surface source to calibrate the aerial survey instrument on the ground, and that it is found in the light of the exchanged principle of the gamma ray when the single point source replaces the unlimited surface source to calibrate aerial surveying instrument in the air. Meanwhile through the theoretical analysis, the receiving rate of the crystal bottom and side surfaces is calculated when aerial surveying instrument receives gamma ray. The mathematical expression of the gamma ray decaying following height according to the Jinge function regularity is got. According to this regularity, the absorbing coefficient that air absorbs the gamma ray and the detective efficiency coefficient of the crystal is calculated based on the ground and air measuring value of the bottom surface receiving count rate (derived from total receiving count rate of the bottom and side surface). Finally, according to the measuring value, it is proved that imitating the change of total receiving gamma ray exposure rate of the bottom and side surfaces with this regularity in a certain high area is feasible

Energy and Emission Characteristics of a Short-Arc Xenon Flash Lamp Under "Saturated" Optical Brightness Conditions

Science.gov (United States)

Kamrukov, A. S.; Kireev, S. G.; Kozlov, N. P.; Shashkovskii, S. G.

2017-09-01

We present the results of a study of the electrical, energy, and spectral brightness characteristics of an experimental three-electrode high-pressure xenon flash lamp under conditions ensuring close to maximum possible spectral brightness for the xenon emission. We show that under saturated optical brightness conditions (brightness temperature in the visible region of the spectrum 30,000 K), emission of a pulsed discharge in xenon is quite different from the emission from an ideal blackbody: the maximum brightness temperatures are 24,000 K in the short-wavelength UV region and 19,000 K in the near IR range. The relative fraction of UV radiation in the emission spectrum of the lamp is >50%, which lets us consider such lamps as promising broadband sources of radiation with high spectral brightness for many important practical applications.

Confusion-limited extragalactic source survey at 4.755 GHz. I. Source list and areal distributions

International Nuclear Information System (INIS)

Ledden, J.E.; Broderick, J.J.; Condon, J.J.; Brown, R.L.

1980-01-01

A confusion-limited 4.755-GHz survey covering 0.00 956 sr between right ascensions 07/sup h/05/sup m/ and 18/sup h/ near declination +35 0 has been made with the NRAO 91-m telescope. The survey found 237 sources and is complete above 15 mJy. Source counts between 15 and 100 mJy were obtained directly. The P(D) distribution was used to determine the number counts between 0.5 and 13.2 mJy, to search for anisotropy in the density of faint extragalactic sources, and to set a 99%-confidence upper limit of 1.83 mK to the rms temperature fluctuation of the 2.7-K cosmic microwave background on angular scales smaller than 7.3 arcmin. The discrete-source density, normalized to the static Euclidean slope, falls off sufficiently rapidly below 100 mJy that no new population of faint flat-spectrum sources is required to explain the 4.755-GHz source counts

Raman beam combining for laser brightness enhancement

Science.gov (United States)

Dawson, Jay W.; Allen, Graham S.; Pax, Paul H.; Heebner, John E.; Sridharan, Arun K.; Rubenchik, Alexander M.; Barty, Chrisopher B. J.

2015-10-27

An optical source capable of enhanced scaling of pulse energy and brightness utilizes an ensemble of single-aperture fiber lasers as pump sources, with each such fiber laser operating at acceptable pulse energy levels. Beam combining involves stimulated Raman scattering using a Stokes' shifted seed beam, the latter of which is optimized in terms of its temporal and spectral properties. Beams from fiber lasers can thus be combined to attain pulses with peak energies in excess of the fiber laser self-focusing limit of 4 MW while retaining the advantages of a fiber laser system of high average power with good beam quality.

X-RAY-EMITTING STARS IDENTIFIED FROM THE ROSAT ALL-SKY SURVEY AND THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Agueeros, Marcel A.; Newsom, Emily R.; Anderson, Scott F.; Hawley, Suzanne L.; Silvestri, Nicole M.; Szkody, Paula; Covey, Kevin R.; Posselt, Bettina; Margon, Bruce; Voges, Wolfgang

2009-01-01

The ROSAT All-Sky Survey (RASS) was the first imaging X-ray survey of the entire sky. Combining the RASS Bright and Faint Source Catalogs yields an average of about three X-ray sources per square degree. However, while X-ray source counterparts are known to range from distant quasars to nearby M dwarfs, the RASS data alone are often insufficient to determine the nature of an X-ray source. As a result, large-scale follow-up programs are required to construct samples of known X-ray emitters. We use optical data produced by the Sloan Digital Sky Survey (SDSS) to identify 709 stellar X-ray emitters cataloged in the RASS and falling within the SDSS Data Release 1 footprint. Most of these are bright stars with coronal X-ray emission unsuitable for SDSS spectroscopy, which is designed for fainter objects (g > 15 [mag]). Instead, we use SDSS photometry, correlations with the Two Micron All Sky Survey and other catalogs, and spectroscopy from the Apache Point Observatory 3.5 m telescope to identify these stellar X-ray counterparts. Our sample of 707 X-ray-emitting F, G, K, and M stars is one of the largest X-ray-selected samples of such stars. We derive distances to these stars using photometric parallax relations appropriate for dwarfs on the main sequence, and use these distances to calculate L X . We also identify a previously unknown cataclysmic variable (CV) as a RASS counterpart. Separately, we use correlations of the RASS and the SDSS spectroscopic catalogs of CVs and white dwarfs (WDs) to study the properties of these rarer X-ray-emitting stars. We examine the relationship between (f X /f g ) and the equivalent width of the Hβ emission line for 46 X-ray-emitting CVs and discuss tentative classifications for a subset based on these quantities. We identify 17 new X-ray-emitting DA (hydrogen) WDs, of which three are newly identified WDs. We report on follow-up observations of three candidate cool X-ray-emitting WDs (one DA and two DB (helium) WDs); we have not

SPT-GMOS: A GEMINI/GMOS-SOUTH SPECTROSCOPIC SURVEY OF GALAXY CLUSTERS IN THE SPT-SZ SURVEY

International Nuclear Information System (INIS)

Bayliss, M. B.; Ruel, J.; Stubbs, C. W.; Allen, S. W.; Applegate, D. E.; Ashby, M. L. N.; Bautz, M.; Benson, B. A.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Bleem, L. E.; Bocquet, S.; Brodwin, M.; Capasso, R.; Chiu, I.; Cho, H-M.; Clocchiatti, A.; Crites, A. T.; Haan, T. de

2016-01-01

We present the results of SPT-GMOS, a spectroscopic survey with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South. The targets of SPT-GMOS are galaxy clusters identified in the SPT-SZ survey, a millimeter-wave survey of 2500 deg 2 of the southern sky using the South Pole Telescope (SPT). Multi-object spectroscopic observations of 62 SPT-selected galaxy clusters were performed between 2011 January and 2015 December, yielding spectra with radial velocity measurements for 2595 sources. We identify 2243 of these sources as galaxies, and 352 as stars. Of the galaxies, we identify 1579 as members of SPT-SZ galaxy clusters. The primary goal of these observations was to obtain spectra of cluster member galaxies to estimate cluster redshifts and velocity dispersions. We describe the full spectroscopic data set and resulting data products, including galaxy redshifts, cluster redshifts, and velocity dispersions, and measurements of several well-known spectral indices for each galaxy: the equivalent width, W , of [O ii] λλ 3727, 3729 and H- δ , and the 4000 Å break strength, D4000. We use the spectral indices to classify galaxies by spectral type (i.e., passive, post-starburst, star-forming), and we match the spectra against photometric catalogs to characterize spectroscopically observed cluster members as a function of brightness (relative to m ⋆ ). Finally, we report several new measurements of redshifts for ten bright, strongly lensed background galaxies in the cores of eight galaxy clusters. Combining the SPT-GMOS data set with previous spectroscopic follow-up of SPT-SZ galaxy clusters results in spectroscopic measurements for >100 clusters, or ∼20% of the full SPT-SZ sample.

SPT-GMOS: A Gemini/GMOS-South Spectroscopic Survey of Galaxy Clusters in the SPT-SZ Survey

Science.gov (United States)

Bayliss, M. B.; Ruel, J.; Stubbs, C. W.; Allen, S. W.; Applegate, D. E.; Ashby, M. L. N.; Bautz, M.; Benson, B. A.; Bleem, L. E.; Bocquet, S.; Brodwin, M.; Capasso, R.; Carlstrom, J. E.; Chang, C. L.; Chiu, I.; Cho, H.-M.; Clocchiatti, A.; Crawford, T. M.; Crites, A. T.; de Haan, T.; Desai, S.; Dietrich, J. P.; Dobbs, M. A.; Doucouliagos, A. N.; Foley, R. J.; Forman, W. R.; Garmire, G. P.; George, E. M.; Gladders, M. D.; Gonzalez, A. H.; Gupta, N.; Halverson, N. W.; Hlavacek-Larrondo, J.; Hoekstra, H.; Holder, G. P.; Holzapfel, W. L.; Hou, Z.; Hrubes, J. D.; Huang, N.; Jones, C.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; von der Linden, A.; Luong-Van, D.; Mantz, A.; Marrone, D. P.; McDonald, M.; McMahon, J. J.; Meyer, S. S.; Mocanu, L. M.; Mohr, J. J.; Murray, S. S.; Padin, S.; Pryke, C.; Rapetti, D.; Reichardt, C. L.; Rest, A.; Ruhl, J. E.; Saliwanchik, B. R.; Saro, A.; Sayre, J. T.; Schaffer, K. K.; Schrabback, T.; Shirokoff, E.; Song, J.; Spieler, H. G.; Stalder, B.; Stanford, S. A.; Staniszewski, Z.; Stark, A. A.; Story, K. T.; Vanderlinde, K.; Vieira, J. D.; Vikhlinin, A.; Williamson, R.; Zenteno, A.

2016-11-01

We present the results of SPT-GMOS, a spectroscopic survey with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South. The targets of SPT-GMOS are galaxy clusters identified in the SPT-SZ survey, a millimeter-wave survey of 2500 deg2 of the southern sky using the South Pole Telescope (SPT). Multi-object spectroscopic observations of 62 SPT-selected galaxy clusters were performed between 2011 January and 2015 December, yielding spectra with radial velocity measurements for 2595 sources. We identify 2243 of these sources as galaxies, and 352 as stars. Of the galaxies, we identify 1579 as members of SPT-SZ galaxy clusters. The primary goal of these observations was to obtain spectra of cluster member galaxies to estimate cluster redshifts and velocity dispersions. We describe the full spectroscopic data set and resulting data products, including galaxy redshifts, cluster redshifts, and velocity dispersions, and measurements of several well-known spectral indices for each galaxy: the equivalent width, W, of [O II] λλ3727, 3729 and H-δ, and the 4000 Å break strength, D4000. We use the spectral indices to classify galaxies by spectral type (i.e., passive, post-starburst, star-forming), and we match the spectra against photometric catalogs to characterize spectroscopically observed cluster members as a function of brightness (relative to m⋆). Finally, we report several new measurements of redshifts for ten bright, strongly lensed background galaxies in the cores of eight galaxy clusters. Combining the SPT-GMOS data set with previous spectroscopic follow-up of SPT-SZ galaxy clusters results in spectroscopic measurements for >100 clusters, or ∼20% of the full SPT-SZ sample.

Space charge and wake field analysis for a high brightness electron source

International Nuclear Information System (INIS)

Parsa, Z.

1991-01-01

We present a brief overview of the formalism used, and some simulation results for transverse and longitudinal motion of a bunch of particles moving through a cavity (e.g., the Brookhaven National Laboratory high brightness photocathode gun), including effects of the accelerating field, space charge forces (e.g., arising from the interaction of the cavity surface and the self field of the bunch). 3 refs., 12 figs

Unidentified point sources in the IRAS minisurvey

Science.gov (United States)

Houck, J. R.; Soifer, B. T.; Neugebauer, G.; Beichman, C. A.; Aumann, H. H.; Clegg, P. E.; Gillett, F. C.; Habing, H. J.; Hauser, M. G.; Low, F. J.

1984-01-01

Nine bright, point-like 60 micron sources have been selected from the sample of 8709 sources in the IRAS minisurvey. These sources have no counterparts in a variety of catalogs of nonstellar objects. Four objects have no visible counterparts, while five have faint stellar objects visible in the error ellipse. These sources do not resemble objects previously known to be bright infrared sources.

Intermittent episodes of bright light suppress myopia in the chicken more than continuous bright light.

Directory of Open Access Journals (Sweden)

Weizhong Lan

Full Text Available PURPOSE: Bright light has been shown a powerful inhibitor of myopia development in animal models. We studied which temporal patterns of bright light are the most potent in suppressing deprivation myopia in chickens. METHODS: Eight-day-old chickens wore diffusers over one eye to induce deprivation myopia. A reference group (n = 8 was kept under office-like illuminance (500 lux at a 10:14 light:dark cycle. Episodes of bright light (15 000 lux were super-imposed on this background as follows. Paradigm I: exposure to constant bright light for either 1 hour (n = 5, 2 hours (n = 5, 5 hours (n = 4 or 10 hours (n = 4. Paradigm II: exposure to repeated cycles of bright light with 50% duty cycle and either 60 minutes (n = 7, 30 minutes (n = 8, 15 minutes (n = 6, 7 minutes (n = 7 or 1 minute (n = 7 periods, provided for 10 hours. Refraction and axial length were measured prior to and immediately after the 5-day experiment. Relative changes were analyzed by paired t-tests, and differences among groups were tested by one-way ANOVA. RESULTS: Compared with the reference group, exposure to continuous bright light for 1 or 2 hours every day had no significant protective effect against deprivation myopia. Inhibition of myopia became significant after 5 hours of bright light exposure but extending the duration to 10 hours did not offer an additional benefit. In comparison, repeated cycles of 1:1 or 7:7 minutes of bright light enhanced the protective effect against myopia and could fully suppress its development. CONCLUSIONS: The protective effect of bright light depends on the exposure duration and, to the intermittent form, the frequency cycle. Compared to the saturation effect of continuous bright light, low frequency cycles of bright light (1:1 min provided the strongest inhibition effect. However, our quantitative results probably might not be directly translated into humans, but rather need further amendments in clinical studies.

Intermittent episodes of bright light suppress myopia in the chicken more than continuous bright light.

Science.gov (United States)

Lan, Weizhong; Feldkaemper, Marita; Schaeffel, Frank

2014-01-01

Bright light has been shown a powerful inhibitor of myopia development in animal models. We studied which temporal patterns of bright light are the most potent in suppressing deprivation myopia in chickens. Eight-day-old chickens wore diffusers over one eye to induce deprivation myopia. A reference group (n = 8) was kept under office-like illuminance (500 lux) at a 10:14 light:dark cycle. Episodes of bright light (15 000 lux) were super-imposed on this background as follows. Paradigm I: exposure to constant bright light for either 1 hour (n = 5), 2 hours (n = 5), 5 hours (n = 4) or 10 hours (n = 4). Paradigm II: exposure to repeated cycles of bright light with 50% duty cycle and either 60 minutes (n = 7), 30 minutes (n = 8), 15 minutes (n = 6), 7 minutes (n = 7) or 1 minute (n = 7) periods, provided for 10 hours. Refraction and axial length were measured prior to and immediately after the 5-day experiment. Relative changes were analyzed by paired t-tests, and differences among groups were tested by one-way ANOVA. Compared with the reference group, exposure to continuous bright light for 1 or 2 hours every day had no significant protective effect against deprivation myopia. Inhibition of myopia became significant after 5 hours of bright light exposure but extending the duration to 10 hours did not offer an additional benefit. In comparison, repeated cycles of 1:1 or 7:7 minutes of bright light enhanced the protective effect against myopia and could fully suppress its development. The protective effect of bright light depends on the exposure duration and, to the intermittent form, the frequency cycle. Compared to the saturation effect of continuous bright light, low frequency cycles of bright light (1:1 min) provided the strongest inhibition effect. However, our quantitative results probably might not be directly translated into humans, but rather need further amendments in clinical studies.

Radio identifications of IRAS point sources with b greater than 30 deg

International Nuclear Information System (INIS)

Condon, J.J.; Broderick, J.J.; Virginia Polytechnic Institute and State Univ., Blacksburg)

1986-01-01

The present radio identifications of IRAS point sources on the basis of Green Bank 1400 MHz survey maps notes that 365 hot IR sources are not detectable radio sources, and that nearly all cool high latitude IRAS sources are extragalactic. The fainter IR-source identifications encompass optically bright quasars, BL Lac objects, Seyfert galaxies, and elliptical galaxies. No IRAS sources could be identified with distant elliptical radio galaxies, so that although the radio and IR fluxes of most IRAS extragalactic sources are tightly correlated, complete samples of strong radio and IR sources are almost completely disjoint; no more than 1 percent of the IR sources are radio sources and less than 1 percent of the radio sources are IR ones. 35 references

Low-Surface-Brightness Galaxies: Hidden Galaxies Revealed

Science.gov (United States)

Bothun, G.; Impey, C.; McGaugh, S.

1997-07-01

In twenty years, low surface brightness (LSB) galaxies have evolved from being an idiosyncratic notion to being one of the major baryonic repositories in the Universe. The story of their discovery and the characterization of their properties is told here. Their recovery from the noise of the night sky background is a strong testament to the severity of surface brightness selection effects. LSB galaxies have a number of remarkable properties which distinguish them from the more familiar Hubble Sequence of spirals. The two most important are 1) they evolve at a significantly slower rate and may well experience star formation outside of the molecular cloud environment, 2) they are embedded in dark matter halos which are of lower density and more extended than the halos around high surface brightness (HSB) disk galaxies. Compared to HSB disks, LSB disks are strongly dark matter dominated at all radii and show a systematic increase in $M/L$ with decreasing central surface brightness. In addition, the recognition that large numbers of LSB galaxies actually exist has changed the form of the galaxy luminosity function and has clearly increased the space density of galaxies at z =0. Recent CCD surveys have uncovered a population of red LSB disks that may be related to the excess of faint blue galaxies detected at moderate redshifts. LSB galaxies offer us a new window into galaxy evolution and formation which is every bit as important as those processes which have produced easy to detect galaxies. Indeed, the apparent youth of some LSB galaxies suggest that galaxy formation is a greatly extended process. While the discovery of LSB galaxies have lead to new insights, it remains unwise to presume that we now have a representative sample which encompasses all galaxy types and forms. (SECTION: Invited Review Paper)

Bright galaxies at z=9-11 from pure-parallel HST observations: Building a unique sample for JWST with Spitzer/IRAC

Science.gov (United States)

Bouwens, Rychard; Morashita, Takahiro; Stefanon, Mauro; Magee, Dan

2018-05-01

The combination of observations taken by Hubble and Spitzer revealed the unexpected presence of sources as bright as our own Milky Way as early as 400 Myr after the Big Bang, potentially highlighting a new highly efficient regime for star formation in L>L* galaxies at very early times. Yet, the sample of high-quality z>8 galaxies with both HST and Spitzer/IRAC imaging is still small, particularly at the highest luminosities. We propose here to remedy this situation and use Spitzer/IRAC to efficiently follow up the most promising z>8 sources from our Hubble Brightest of Reionizing Galaxies (BoRG) survey, which covers a footprint on the sky similar to CANDELS, provides a deeper search than ground-based surveys like UltraVISTA, and is robust against cosmic variance because of its 210 independent lines of sight. The proposed new 3.6 micron observations will continue our Spitzer cycle 12 and 13 BORG911 programs, targeting 15 additional fields, leveraging over 200 new HST orbits to identify a final sample of about 8 bright galaxies at z >= 8.5. For optimal time use (just 20 hours), our goal is to readily discriminate between z>8 sources (undetected or marginally detected in IRAC) and z 2 interlopers (strongly detected in IRAC) with just 1-2 hours per pointing. The high-quality candidates that we will identify with IRAC will be ideal targets for further studies investigating the ionization state of the distant universe through near-IR Keck/VLT spectroscopy. They will also be uniquely suited to measurement of the redshift and stellar population properties through JWST/NIRSPEC observations, with the potential to elucidate how the first generations of stars are assembled in the earliest stages of the epoch of reionization.

A Survey for Low Surface Brightness Dwarf Galaxies Around M31

OpenAIRE

Armandroff, Taft E.; Davies, James E.; Jacoby, George H.

1998-01-01

By applying a digital filtering technique to 1550 square degrees of the POSS-II in the vicinity of M31, we found two previously unidentified very low surface brightness dwarf galaxies which we designate And V and VI. Follow-up imaging with the KPNO 4-m telescope resolved these into stars easily. The V- and I- band images of And V indicate a distance similar to that of M31, and approximately -1.5. All evidence strongly supports its classification as a dwarf spheroidal companion to M31. Data f...

A selective deficit in the appreciation and recognition of brightness: brightness agnosia?

NARCIS (Netherlands)

Nijboer, T.C.W.; Nys, G.M.S.; van der Smagt, M.J.; de Haan, E.H.F.

2009-01-01

We report a patient with extensive brain damage in the right hemisphere who demonstrated a severe impairment in the appreciation of brightness. Acuity, contrast sensitivity as well as luminance discrimination were normal, suggesting her brightness impairment is not a mere consequence of low-level

The Southern HII Region Discovery Survey: The Bright Catalog

Science.gov (United States)

Wenger, Trey V.; Dickey, John M.; Jordan, Christopher H.; Balser, Dana; Armentrout, William Paul; Anderson, Loren; Bania, Thomas; Dawson, Joanne; McClure-Griffiths, Naomi M.; Shea, Jeanine

2018-01-01

HII regions, the zones of ionized gas surrounding recently formed high-mass stars, are the archetypical tracers of Galactic structure. The census of Galactic HII regions in the Southern sky is vastly incomplete due to a lack of sensitive radio recombination line (RRL) surveys. The Southern HII Region Discovery Survey (SHRDS) is a 900-hour Australia Telescope Compact Array cm-wavelength RRL and continuum emission survey of hundreds of third and fourth quadrant Galactic HII region candidates. These candidates are identified in the Widefield Infrared Survey Explorer (WISE) Catalog of Galactic HII Regions based on coincident 10 micron (WISE) and 20 cm (Southern Galactic Plane Survey) emission. The SHRDS is an extension of HII Region Discovery Surveys in the Northern sky with the Green Bank Telescope and Arecibo Telescope which discovered ~800 new HII regions. In the first 500 hours of the SHRDS, we targeted the 249 brightest HII region candidates and 33 previously known HII regions. We discuss the data reduction, analysis, and preliminary results from this first stage of the survey.

Survey of residential magnetic field sources

International Nuclear Information System (INIS)

Zaffanella, L.E.

1992-09-01

A nationwide survey of 1000 residences is underway to determine the sources and characteristics of magnetic fields in the home. This report describes the goals, statistical sampling methods, measurement protocols, and experiences in measuring the first 707 residences of the survey. Some preliminary analysis of the data is also included. Investigators designed a sampling method to randomly select the participating utilities as well as the residential customers for the study. As a first step in the project, 18 utility employee residences were chosen to validate a relatively simple measurement protocol against the results of a more complete and intrusive method. Using the less intrusive measurement protocol, researchers worked closely with representatives from EPRI member utilities to enter customer residences and measure the magnetic fields found there. Magnetic field data were collected in different locations inside and around the residences. Twenty-four-hour recorders were left in the homes overnight. Tests showed that the simplified measurement protocol is adequate for achieving the goals of the study. Methods were developed for analyzing the field caused by a residence's ground current, the lateral field profiles of field lines, and the field measured around the periphery of the residences. Methods of residential source detection were developed that allow identification of sources such as ground connections at an electrical subpanel, two-wire multiple-way switches, and underground or overhead net currents exiting the periphery of a residence

All-sky brightness monitoring of light pollution with astronomical methods.

Science.gov (United States)

Rabaza, O; Galadí-Enríquez, D; Estrella, A Espín; Dols, F Aznar

2010-06-01

This paper describes a mobile prototype and a protocol to measure light pollution based on astronomical methods. The prototype takes three all-sky images using BVR filters of the Johnson-Cousins astronomical photometric system. The stars are then identified in the images of the Hipparcos and General Catalogue of Photometric Data II astronomical catalogues, and are used as calibration sources. This method permits the measurement of night-sky brightness and facilitates an estimate of which fraction is due to the light up-scattered in the atmosphere by a wide variety of man-made sources. This is achieved by our software, which compares the sky background flux to that of many stars of known brightness. The reduced weight and dimensions of the prototype allow the user to make measurements from virtually any location. This prototype is capable of measuring the sky distribution of light pollution, and also provides an accurate estimate of the background flux at each photometric band. (c) 2010 Elsevier Ltd. All rights reserved.

High-brightness rf linear accelerators

International Nuclear Information System (INIS)

Jameson, R.A.

1986-01-01

The issue of high brightness and its ramifications in linacs driven by radio-frequency fields is discussed. A history of the RF linacs is reviewed briefly. Some current applications are then examined that are driving progress in RF linacs. The physics affecting the brightness of RF linacs is then discussed, followed by the economic feasibility of higher brightness machines

The effects of variability on the number-flux-density relationship for radio sources

International Nuclear Information System (INIS)

Schuch, N.J.

1981-01-01

It has been known for some time that the number-flux-density relationship for radio sources requires a population of sources whose properties evolve with cosmological epoch, at least in models where the redshifts are all taken to be cosmological. In particular, the surveys made at metre wavelengths show, for bright sources, a slope of the log N -log S curve which is steeper than the value -1.5 expected in a static, non-evolving Euclidean universe. Here, N is the number of radio sources brighter than flux density S. Expansion without evolution in conventional geometrical models predicts slopes flatter than -1.5. If the radio survey is carried out at higher frequencies (typically 2.7 or 5 GHz - 11 or 6 cm wavelength), the slope of the log N -log S curve is steeper than -1.5 but not so steep as the slopes found for the low-frequency surveys. Many of the sources found in high-frequency surveys have radio spectra with relatively higher flux-densities in the centimetre range; these sources are frequently variable at high frequencies, with time-scales from a month or two upwards. Some possible effects of the variations on the observed counts of radio sources are considered. (author)

Powerful warm infrared sources in early-type galaxies

International Nuclear Information System (INIS)

Dressel, L.L.

1988-01-01

IRAS far-infrared sources have been identified with 129 S0, Sa, Sb, and Sc galaxies in a statistically complete sample of 738 galaxies brighter than 14.5 mag and smaller than 4.0 arcmin. In most cases, the far-IR colors and the ratios of far-IR flux to radio flux density are those of normal galactic disks and/or starbursts. The most powerful far-IR sources in S0 and Sa galaxies are just as powerful as the strongest far-IR sources in Sb and Sc galaxies. Bright-IR sources in S0 and Sa galaxies are warm; those in Sc galaxies are cool. Sb galaxies have both warm and cool IR sources. Bright warm IR sources occur much more frequently in barred galaxies than in galaxies without bars for types S0, Sa, and Sb. Bright, cool IR sources are found with increasing frequency along the Hubble sequence, regardless of the presence or absence of a bar. At least some S0 galaxies with warm, bright IR sources have peculiar morphologies and ambiguous classifications. 22 references

THE ACS FORNAX CLUSTER SURVEY. IV. DEPROJECTION OF THE SURFACE BRIGHTNESS PROFILES OF EARLY-TYPE GALAXIES IN THE VIRGO AND FORNAX CLUSTERS: INVESTIGATING THE 'CORE/POWER-LAW DICHOTOMY'

International Nuclear Information System (INIS)

Glass, Lisa; Ferrarese, Laura; Cote, Patrick; Blakeslee, John P.; Chen, Chin-Wei; Jordan, Andres; Infante, Leopoldo; Peng, Eric; Mei, Simona; Tonry, John L.; West, Michael J.

2011-01-01

Although early observations with the Hubble Space Telescope (HST) pointed to a sharp dichotomy among early-type galaxies in terms of the logarithmic slope γ' of their central surface brightness profiles, several studies in the past few years have called this finding into question. In particular, recent imaging surveys of 143 early-type galaxies belonging to the Virgo and Fornax Clusters using the Advanced Camera for Surveys (ACS) on board HST have not found a dichotomy in γ', but instead a systematic progression from central luminosity deficit to excess relative to the inward extrapolation of the best-fitting global Sersic model. Given that earlier studies also found that the dichotomy persisted when analyzing the deprojected density profile slopes, we investigate the distribution of the three-dimensional luminosity density profiles of the ACS Virgo and Fornax Cluster Survey galaxies. Having fitted the surface brightness profiles with modified Sersic models, we then deproject the galaxies using an Abel integral and measure the inner slopes γ 3D of the resulting luminosity density profiles at various fractions of the effective radius R e . We find no evidence of a dichotomy, but rather, a continuous variation in the central luminosity profiles as a function of galaxy magnitude. We introduce a parameter, Δ 3D , that measures the central deviation of the deprojected luminosity profiles from the global Sersic fit, showing that this parameter varies smoothly and systematically along the luminosity function.

Survey, alignment, and beam stability at the Advanced Light Source

International Nuclear Information System (INIS)

Krebs, G.F.

1997-10-01

This paper describes survey and alignment at the Lawrence Berkeley Laboratories Advanced Light Source (ALS) accelerators from 1993 to 1997. The ALS is a third generation light source requiring magnet alignment to within 150 microns. To accomplish this, a network of monuments was established and maintained. Monthly elevation surveys show the movement of the floor over time. Inclinometers have recently been employed to give real time information about magnet, vacuum tank and magnet girder motion in the ALS storage ring

Modeling laser brightness from cross Porro prism resonators

Science.gov (United States)

Forbes, Andrew; Burger, Liesl; Litvin, Igor Anatolievich

2006-08-01

Laser brightness is a parameter often used to compare high power laser beam delivery from various sources, and incorporates both the power contained in the particular mode, as well as the propagation of that mode through the beam quality factor, M2. In this study a cross Porro prism resonator is considered; crossed Porro prism resonators have been known for some time, but until recently have not been modeled as a complete physical optics system that allows the modal output to be determined as a function of the rotation angle of the prisms. In this paper we consider the diffraction losses as a function of the prism rotation angle relative to one another, and combine this with the propagation of the specific modes to determine the laser output brightness as a function of the prism orientation.

High brightness fiber laser pump sources based on single emitters and multiple single emitters

Science.gov (United States)

Scheller, Torsten; Wagner, Lars; Wolf, Jürgen; Bonati, Guido; Dörfel, Falk; Gabler, Thomas

2008-02-01

Driven by the potential of the fiber laser market, the development of high brightness pump sources has been pushed during the last years. The main approaches to reach the targets of this market had been the direct coupling of single emitters (SE) on the one hand and the beam shaping of bars and stacks on the other hand, which often causes higher cost per watt. Meanwhile the power of single emitters with 100μm emitter size for direct coupling increased dramatically, which also pushed a new generation of wide stripe emitters or multi emitters (ME) of up to 1000μm emitter size respectively "minibars" with apertures of 3 to 5mm. The advantage of this emitter type compared to traditional bars is it's scalability to power levels of 40W to 60W combined with a small aperture which gives advantages when coupling into a fiber. We show concepts using this multiple single emitters for fiber coupled systems of 25W up to 40W out of a 100μm fiber NA 0.22 with a reasonable optical efficiency. Taking into account a further efficiency optimization and an increase in power of these devices in the near future, the EUR/W ratio pushed by the fiber laser manufacturer will further decrease. Results will be shown as well for higher power pump sources. Additional state of the art tapered fiber bundles for photonic crystal fibers are used to combine 7 (19) pump sources to output powers of 100W (370W) out of a 130μm (250μm) fiber NA 0.6 with nominal 20W per port. Improving those TFB's in the near future and utilizing 40W per pump leg, an output power of even 750W out of 250μm fiber NA 0.6 will be possible. Combined Counter- and Co-Propagated pumping of the fiber will then lead to the first 1kW fiber laser oscillator.

Completion of the brightness upgrade of the ALS

International Nuclear Information System (INIS)

Steier, C; Madur, A; Bailey, B; Berg, K; Biocca, A; Black, A; Casey, P; Colomb, D; Gunion, B; Li, N; Marks, S; Nishimura, H; Pappas, C; Petermann, K; Portmann, G; Prestemon, S; Rawlins, A; Robin, D; Rossi, S; Scarvie, T

2014-01-01

The Advanced Light Source (ALS) at Berkeley Lab remains one of the brightest sources for soft x-rays worldwide. A multiyear upgrade of the ALS is underway, which includes new and replacement x-ray beamlines, a replacement of many of the original insertion devices and many upgrades to the accelerator. The accelerator upgrade that affects the ALS performance most directly is the ALS brightness upgrade [1], which reduces the horizontal emittance from 6.3 to 2.0 nm (2.5 nm effective). Magnets for this upgrade were installed in late 2012 and early 2013 followed by user operation with the reduced emittance.

A Survey of Open Source Tools for Business Intelligence

DEFF Research Database (Denmark)

Thomsen, Christian; Pedersen, Torben Bach

2009-01-01

The industrial use of open source Business Intelligence (BI) tools is becoming more common, but is still not as widespread as for other types of software. It is therefore of interest to explore which possibilities are available for open source BI and compare the tools. In this survey paper, we co...

INTERFEROMETRIC MONITORING OF GAMMA-RAY BRIGHT AGNs. I. THE RESULTS OF SINGLE-EPOCH MULTIFREQUENCY OBSERVATIONS

Energy Technology Data Exchange (ETDEWEB)

Lee, Sang-Sung; Wajima, Kiyoaki; Algaba, Juan-Carlos; Zhao, Guang-Yao; Hodgson, Jeffrey A.; Byun, Do-Young; Kang, Sincheol; Kim, Soon-Wook; Kino, Motoki [Korea Astronomy and Space Science Institute, 776 Daedeok-daero, Yuseong-gu, Daejeon 34055 (Korea, Republic of); Kim, Dae-Won; Park, Jongho; Kim, Jae-Young; Trippe, Sascha [Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826 (Korea, Republic of); Miyazaki, Atsushi [Japan Space Forum, 3-2-1, Kandasurugadai, Chiyoda-ku, Tokyo 101-0062 Japan (Japan); Kim, Jeong-Sook, E-mail: sslee@kasi.re.kr [National Astronomical Observatory of Japan, 2211 Osawa, Mitaka, Tokyo 1818588 (Japan)

2016-11-01

We present results of single-epoch very long baseline interferometry (VLBI) observations of gamma-ray bright active galactic nuclei (AGNs) using the Korean VLBI Network (KVN) at the 22, 43, 86, and 129 GHz bands, which are part of a KVN key science program, Interferometric Monitoring of Gamma-Ray Bright AGNs. We selected a total of 34 radio-loud AGNs of which 30 sources are gamma-ray bright AGNs with flux densities of >6 × 10{sup −10} ph cm{sup −2} s{sup −1}. Single-epoch multifrequency VLBI observations of the target sources were conducted during a 24 hr session on 2013 November 19 and 20. All observed sources were detected and imaged at all frequency bands, with or without a frequency phase transfer technique, which enabled the imaging of 12 faint sources at 129 GHz, except for one source. Many of the target sources are resolved on milliarcsecond scales, yielding a core-jet structure, with the VLBI core dominating the synchrotron emission on a milliarcsecond scale. CLEAN flux densities of the target sources are 0.43–28 Jy, 0.32–21 Jy, 0.18–11 Jy, and 0.35–8.0 Jy in the 22, 43, 86, and 129 GHz bands, respectively. Spectra of the target sources become steeper at higher frequency, with spectral index means of −0.40, −0.62, and −1.00 in the 22–43 GHz, 43–86 GHz and 86–129 GHz bands, respectively, implying that the target sources become optically thin at higher frequencies (e.g., 86–129 GHz).

On the completeness of a sample of bright quasars selected by colour excess in the direction of the North Galactic Pole

International Nuclear Information System (INIS)

Warnock, A. III; Usher, P.D.

1986-01-01

The Medium Bright Quasar survey (MBQS) shows evidence for a dearth of bright quasars in a Palomar Schmidt field centred on Selected Area (SA) 57 near the North Galactic Pole, compared to similar fields centred on SA 28, 29, 55, and 94. The SA 57 field has been searched again for bright quasar candidates with the held of a second survey plate exposed according to a slightly modified Haro-Luyten three-colour (Tonantzintla) prescription. Candidates so selected have both a blue and ultraviolet excess (B-UVX). The main result of the paper is that there appear to be no B-UVX quasars in the SA 57 field that are brighter than B=17.25 mag. The significance of this apparent anomaly is briefly discussed. (author)

RELIABLE IDENTIFICATIONS OF ACTIVE GALACTIC NUCLEI FROM THE WISE, 2MASS, AND ROSAT ALL-SKY SURVEYS

International Nuclear Information System (INIS)

Edelson, R.; Malkan, M.

2012-01-01

We have developed the ''S IX '' statistic to identify bright, highly likely active galactic nucleus (AGN) candidates solely on the basis of Wide-field Infrared Survey Explorer (WISE), Two Micron All-Sky Survey (2MASS), and ROSAT all-sky survey (RASS) data. This statistic was optimized with data from the preliminary WISE survey and the Sloan Digital Sky Survey, and tested with Lick 3 m Kast spectroscopy. We find that sources with S IX 95% likelihood of being an AGN (defined in this paper as a Seyfert 1, quasar, or blazar). This statistic was then applied to the full WISE/2MASS/RASS dataset, including the final WISE data release, to yield the ''W2R'' sample of 4316 sources with S IX 2 , permitting construction of AGN samples in any sufficiently large region of sky.

THE STAR FORMATION AND NUCLEAR ACCRETION HISTORIES OF NORMAL GALAXIES IN THE AGES SURVEY

International Nuclear Information System (INIS)

Watson, Casey R.; Kochanek, Christopher S.; Forman, William R.; Hickox, Ryan C.; Jones, Christine J.; Kenter, Almus T.; Murray, Steve S.; Vikhlinin, Alexey; Fazio, Giovani G.; Green, Paul J.; Brown, Michael J. I.; Brand, Kate; Dey, Arjun; Jannuzi, Buell T.; Rieke, Marcia; Eisenstein, Daniel J.; McNamara, Brian R.; Shields, Joseph C.

2009-01-01

We combine IR, optical, and X-ray data from the overlapping, 9.3 deg 2 NOAO Deep Wide-Field Survey, AGN and Galaxy Evolution Survey (AGES), and XBooetes Survey to measure the X-ray evolution of 6146 normal galaxies as a function of absolute optical luminosity, redshift, and spectral type over the largely unexplored redshift range 0.1 ∼ 3±1 , in agreement with the trends found for samples of bright, individually detectable starburst galaxies and AGN. Our work also corroborates the results of many previous stacking analyses of faint source populations, with improved statistics.

Beam extraction dynamics at the space-charge-limit of the high brightness E-XFEL electron source at DESY-PITZ

Energy Technology Data Exchange (ETDEWEB)

Chen, Ye; Gjonaj, Erion; Weiland, Thomas [TEMF, Technische Universitaet Darmstadt, Schlossgartenstrasse 8, 64289 Darmstadt (Germany)

2015-07-01

The physics of the photoemission, as one of the key issues for successful operation of linac based free-electron lasers like the European X-ray Free Electron Laser (E-XFEL) and the Free-electron Laser in Hamburg (FLASH), is playing an increasingly important role in the high brightness DESY-PITZ electron source. We study photoemission physics and discuss full three-dimensional numerical modeling of the electron bunch emission. The beam extraction dynamics at the photocathode has been investigated through the 3D fully electromagnetic (EM) Particle-in-Cell (PIC) solver of CST Particle Studio under the assumption of the photoemission source operating at or close to its space charge limit. PIC simulation results have shown good agreements with measurements on total emitted bunch charge for distinct experimental parameters. Further comparisons showed a general failure for the conventional Poisson solver based tracking algorithm to correctly predict the beam dynamics at the space charge limit. It is furthermore found, that fully EM PIC simulations are also consistent with a simple emission model based on the multidimensional Child-Langmuir law.

A review on brightness preserving contrast enhancement methods for digital image

Science.gov (United States)

Rahman, Md Arifur; Liu, Shilong; Li, Ruowei; Wu, Hongkun; Liu, San Chi; Jahan, Mahmuda Rawnak; Kwok, Ngaiming

2018-04-01

Image enhancement is an imperative step for many vision based applications. For image contrast enhancement, popular methods adopt the principle of spreading the captured intensities throughout the allowed dynamic range according to predefined distributions. However, these algorithms take little or no consideration into account of maintaining the mean brightness of the original scene, which is of paramount importance to carry the true scene illumination characteristics to the viewer. Though there have been significant amount of reviews on contrast enhancement methods published, updated review on overall brightness preserving image enhancement methods is still scarce. In this paper, a detailed survey is performed on those particular methods that specifically aims to maintain the overall scene illumination characteristics while enhancing the digital image.

VizieR Online Data Catalog: The CLASS blazar survey. I. (Marcha+, 2001)

Science.gov (United States)

Marcha, M. J.; Caccianiga, A.; Browne, I. W. A.; Jackson, N.

2002-04-01

This paper presents a new complete and well-defined sample of flat-spectrum radio sources (FSRS) selected from the Cosmic Lens All-Sky Survey (CLASS), with the further constraint of a bright (mag<=17.5) optical counterpart. The sample has been designed to produce a large number of low-luminosity blazars in order to test the current unifying models in the low-luminosity regime. In this first paper the new sample is presented and the radio properties of the 325 sources contained therein are discussed. (1 data file).

Do Low Surface Brightness Galaxies Host Stellar Bars?

International Nuclear Information System (INIS)

Cervantes Sodi, Bernardo; Sánchez García, Osbaldo

2017-01-01

With the aim of assessing if low surface brightness galaxies host stellar bars and by studying the dependence of the occurrence of bars as a function of surface brightness, we use the Galaxy Zoo 2 data set to construct a large volume-limited sample of galaxies and then segregate these galaxies as having low or high surface brightness in terms of their central surface brightness. We find that the fraction of low surface brightness galaxies hosting strong bars is systematically lower than that found for high surface brightness galaxies. The dependence of the bar fraction on the central surface brightness is mostly driven by a correlation of the surface brightness with the spin and the gas richness of the galaxies, showing only a minor dependence on the surface brightness. We also find that the length of the bars is strongly dependent on the surface brightness, and although some of this dependence is attributed to the gas content, even at a fixed gas-to-stellar mass ratio, high surface brightness galaxies host longer bars than their low surface brightness counterparts, which we attribute to an anticorrelation of the surface brightness with the spin.

Do Low Surface Brightness Galaxies Host Stellar Bars?

Energy Technology Data Exchange (ETDEWEB)

Cervantes Sodi, Bernardo; Sánchez García, Osbaldo, E-mail: b.cervantes@irya.unam.mx, E-mail: o.sanchez@irya.unam.mx [Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Campus Morelia, A.P. 3-72, C.P. 58089 Michoacán, México (Mexico)

2017-09-20

With the aim of assessing if low surface brightness galaxies host stellar bars and by studying the dependence of the occurrence of bars as a function of surface brightness, we use the Galaxy Zoo 2 data set to construct a large volume-limited sample of galaxies and then segregate these galaxies as having low or high surface brightness in terms of their central surface brightness. We find that the fraction of low surface brightness galaxies hosting strong bars is systematically lower than that found for high surface brightness galaxies. The dependence of the bar fraction on the central surface brightness is mostly driven by a correlation of the surface brightness with the spin and the gas richness of the galaxies, showing only a minor dependence on the surface brightness. We also find that the length of the bars is strongly dependent on the surface brightness, and although some of this dependence is attributed to the gas content, even at a fixed gas-to-stellar mass ratio, high surface brightness galaxies host longer bars than their low surface brightness counterparts, which we attribute to an anticorrelation of the surface brightness with the spin.

Survey of tritiated oil sources and handling practices

International Nuclear Information System (INIS)

Miller, J.M.

1994-08-01

Tritium interactions with oil sources (primarily associated with pumps) in tritium-handling facilities can lead to the incorporation of tritium in the oil and the production of tritiated hydrocarbons. This results in a source of radiological hazard and the need for special handling considerations during maintenance, decontamination, decommissioning and waste packaging and storage. The results of a general survey of tritiated-oil sources and their associated characteristics, handling practices, analysis techniques and waste treatment/storage methods are summarized here. Information was obtained from various tritium-handling laboratories, fusion devices, and CANDU plants. 38 refs., 1 fig

10C survey of radio sources at 15.7 GHz - II. First results

Science.gov (United States)

AMI Consortium; Davies, Mathhew L.; Franzen, Thomas M. O.; Waldram, Elizabeth M.; Grainge, Keith J. B.; Hobson, Michael P.; Hurley-Walker, Natasha; Lasenby, Anthony; Olamaie, Malak; Pooley, Guy G.; Riley, Julia M.; Rodríguez-Gonzálvez, Carmen; Saunders, Richard D. E.; Scaife, Anna M. M.; Schammel, Michel P.; Scott, Paul F.; Shimwell, Timothy W.; Titterington, David J.; Zwart, Jonathan T. L.

2011-08-01

In a previous paper (Paper I), the observational, mapping and source-extraction techniques used for the Tenth Cambridge (10C) Survey of Radio Sources were described. Here, the first results from the survey, carried out using the Arcminute Microkelvin Imager Large Array (LA) at an observing frequency of 15.7 GHz, are presented. The survey fields cover an area of ≈27 deg2 to a flux-density completeness of 1 mJy. Results for some deeper areas, covering ≈12 deg2, wholly contained within the total areas and complete to 0.5 mJy, are also presented. The completeness for both areas is estimated to be at least 93 per cent. The 10C survey is the deepest radio survey of any significant extent (≳0.2 deg2) above 1.4 GHz. The 10C source catalogue contains 1897 entries and is available online. The source catalogue has been combined with that of the Ninth Cambridge Survey to calculate the 15.7-GHz source counts. A broken power law is found to provide a good parametrization of the differential count between 0.5 mJy and 1 Jy. The measured source count has been compared with that predicted by de Zotti et al. - the model is found to display good agreement with the data at the highest flux densities. However, over the entire flux-density range of the measured count (0.5 mJy to 1 Jy), the model is found to underpredict the integrated count by ≈30 per cent. Entries from the source catalogue have been matched with those contained in the catalogues of the NRAO VLA Sky Survey and the Faint Images of the Radio Sky at Twenty-cm survey (both of which have observing frequencies of 1.4 GHz). This matching provides evidence for a shift in the typical 1.4-GHz spectral index to 15.7-GHz spectral index of the 15.7-GHz-selected source population with decreasing flux density towards sub-mJy levels - the spectra tend to become less steep. Automated methods for detecting extended sources, developed in Paper I, have been applied to the data; ≈5 per cent of the sources are found to be extended

Much Ado about Microbunching: Coherent Bunching in High Brightness Electron Beams

Energy Technology Data Exchange (ETDEWEB)

Ratner, Daniel [Stanford Univ., CA (United States)

2011-05-01

The push to provide ever brighter coherent radiation sources has led to the creation of correspondingly bright electron beams. With billions of electrons packed into normalized emittances (phase space) below one micron, collective effects may dominate both the preservation and use of such ultra-bright beams. An important class of collective effects is due to density modulations within the bunch, or microbunching. Microbunching may be deleterious, as in the case of the Microbunching Instability (MBI), or it may drive radiation sources of unprecedented intensity, as in the case of Free Electron Lasers (FELs). In this work we begin by describing models of microbunching due to inherent beam shot noise, which sparks both the MBI as well as SLAC's Linac Coherent Light Source, the world's first hard X-ray laser. We first use this model to propose a mechanism for reducing the inherent beam shot noise as well as for predicting MBI effects. We then describe experimental measurements of the resulting microbunching at LCLS, including optical radiation from the MBI, as well as the first gain length and harmonic measurements from a hard X-ray FEL. In the final chapters, we describe schemes that use external laser modulations to microbunch light sources of the future. In these sections we describe coherent light source schemes for both both linacs and storage rings.

A MID-INFRARED CENSUS OF STAR FORMATION ACTIVITY IN BOLOCAM GALACTIC PLANE SURVEY SOURCES

International Nuclear Information System (INIS)

Dunham, Miranda K.; Robitaille, Thomas P.; Evans, Neal J. II; Schlingman, Wayne M.; Cyganowski, Claudia J.; Urquhart, James

2011-01-01

We present the results of a search for mid-infrared signs of star formation activity in the 1.1 mm sources in the Bolocam Galactic Plane Survey (BGPS). We have correlated the BGPS catalog with available mid-IR Galactic plane catalogs based on the Spitzer Space Telescope GLIMPSE legacy survey and the Midcourse Space Experiment (MSX) Galactic plane survey. We find that 44% (3712 of 8358) of the BGPS sources contain at least one mid-IR source, including 2457 of 5067 (49%) within the area where all surveys overlap (10 deg. s tarlessBGPS sources which were not matched to any mid-IR sources. The mean 1.1 mm flux of each group increases with increasing probability of active star formation. We also find that the 'starless' BGPS sources are the most compact, while the sources with the highest probability of star formation activity are on average more extended with large skirts of emission. A subsample of 280 BGPS sources with known distances demonstrates that mass and mean H 2 column density also increase with probability of star formation activity.

Atmospheric extinction coefficients and night sky brightness at the Xuyi Observation Station

International Nuclear Information System (INIS)

Zhang Hui-Hua; Liu Xiao-Wei; Zhang Hua-Wei; Xiang Mao-Sheng; Yuan Hai-Bo; Zhao Hai-Bin; Yao Jin-Sheng

2013-01-01

We present measurements of the optical broadband atmospheric extinction coefficients and the night sky brightness at the Xuyi Observation Station of Purple Mountain Observatory. The measurements are based on CCD imaging data taken in the Sloan Digital Sky Survey's g, r and i bands with the Xuyi 1.04/1.20 m Schmidt Telescope for the Xuyi Schmidt Telescope Photometric Survey of the Galactic Anti-center (XSTPS-GAC), the photometric part of the Digital Sky Survey of the Galactic Anti-center (DSS-GAC). The data were collected during more than 140 winter nights from 2009 to 2011. We find that the atmospheric extinction coefficients for the g, r and i bands are 0.69, 0.55 and 0.38 mag/airmass, respectively, based on observations taken on several photometric nights. The night sky brightness determined from images with good quality has median values of 21.7, 20.8 and 20.0 mag arcsec −2 and reaches 22.1, 21.2 and 20.4 mag arcsec −2 under the best observing conditions for the g, r and i bands, respectively. The relatively large extinction coefficients compared with other good astronomical observing sites are mainly due to the relatively low elevation (i.e. 180 m) and high humidity at the station.

Proxy magnetometry of the photosphere: why are G-band bright points so bright?

NARCIS (Netherlands)

Rutten, R.J.; Kiselman, Dan; Voort, Luc Rouppe van der; Plez, Bertrand

2000-01-01

We discuss the formation of G-band bright points in terms of standard uxtube modeling, in particular the 1D LTE models constructed by Solanki and coworkers. Combined with LTE spectral synthesis they explain observed G-band bright point contrasts quite well. The G-band contrast increase over the

PePSS - A portable sky scanner for measuring extremely low night-sky brightness

Science.gov (United States)

Kocifaj, Miroslav; Kómar, Ladislav; Kundracik, František

2018-05-01

A new portable sky scanner designed for low-light-level detection at night is developed and employed in night sky brightness measurements in a rural region. The fast readout, adjustable sensitivity and linear response guaranteed in 5-6 orders of magnitude makes the device well suited for narrow-band photometry in both dark areas and bright urban and suburban environments. Quasi-monochromatic night-sky brightness data are advantageous in the accurate characterization of spectral power distribution of scattered and emitted light and, also allows for the possibility to retrieve light output patterns from whole-city light sources. The sky scanner can operate in both night and day regimes, taking advantage of the complementarity of both radiance data types. Due to its inherent very high sensitivity the photomultiplier tube could be used in night sky radiometry, while the spectrometer-equipped system component capable of detecting elevated intensities is used in daylight monitoring. Daylight is a source of information on atmospheric optical properties that in turn are necessary in processing night sky radiances. We believe that the sky scanner has the potential to revolutionize night-sky monitoring systems.

Is 4C+29.48 a γ-ray source?

Science.gov (United States)

Gabányi, K. É.; Frey, S.; An, T.

2018-05-01

Context. The Fermi Large Area Telescope revealed that the extragalactic γ-ray sky is dominated by blazars, active galactic nuclei (AGN) whose jet is seen at very small angle to the line of sight. To associate and then classify the γ-ray sources, data have been collected from lower frequency surveys and observations. Since those have superior angular resolution and positional accuracy compared to the γ-ray observations, some associations are not straightforward. Aims: The γ-ray source 3FGL J1323.0+2942 is associated with the radio source 4C+29.48 and classified as a blazar of unknown type, lacking optical spectrum and redshift. The higher-resolution radio data showed that 4C+29.48 comprises three bright radio-emitting features located within a 1'-diameter area. We aim to reveal their nature and pinpoint the origin of the γ-ray emission. Methods: We (re-)analyzed archival Very Large Array (VLA) and unpublished very long baseline interferometry (VLBI) observations conducted by the Very Long Baseline Array (VLBA) and the European VLBI Network of 4C+29.48. We also collected data form optical, infrared and X-ray surveys. Results: According to the VLBI data, the northernmost complex of 4C+29.48 contains a blazar with a high brightness temperature compact core and a steep-spectrum jet feature. The blazar is positionally coincident with an optical source at a redshift of 1.142. Its mid-infrared colors also support its association with a γ-ray emitting blazar. The two other radio complexes have steep radio spectra similar to AGN-related lobes and do not have optical or infrared counterparts in currently available surveys. Based on the radio morphology, they are unlikely to be related to the blazar. There is an optical source between the two radio features, also detected in infrared wavebands. We discuss the possibilities whether the two radio features are lobes of a radio galaxy, or gravitationally lensed images of a background source. Conclusions: We propose to

Unveiling the Low Surface Brightness Stellar Peripheries of Galaxies

Science.gov (United States)

Ferguson, Annette M. N.

2018-01-01

The low surface brightness peripheral regions of galaxies contain a gold mine of information about how minor mergers and accretions have influenced their evolution over cosmic time. Enormous stellar envelopes and copious amounts of faint tidal debris are natural outcomes of the hierarchical assembly process and the search for and study of these features, albeit highly challenging, offers the potential for unrivalled insight into the mechanisms of galaxy growth. Over the last two decades, there has been burgeoning interest in probing galaxy outskirts using resolved stellar populations. Wide-field surveys have uncovered vast tidal debris features and new populations of very remote globular clusters, while deep Hubble Space Telescope photometry has provided exquisite star formation histories back to the earliest epochs. I will highlight some recent results from studies within and beyond the Local Group and conclude by briefly discussing the great potential of future facilities, such as JWST, Euclid, LSST and WFIRST, for major breakthroughs in low surface brightness galaxy periphery science.

The bright and choked gamma-ray burst contribution to the IceCube and ANTARES low-energy excess

Science.gov (United States)

Denton, Peter B.; Tamborra, Irene

2018-04-01

The increasing statistics of the high-energy neutrino flux observed by the IceCube Observatory points towards an excess of events above the atmospheric neutrino background in the 30–400 TeV energy range. Such an excess is compatible with the findings of the ANTARES Telescope and it would naturally imply the possibility that more than one source class contributes to the observed flux. Electromagnetically hidden sources have been invoked to interpret this excess of events at low energies. By adopting a unified model for the electromagnetically bright and choked gamma-ray bursts and taking into account particle acceleration at the internal and collimation shock radii, we discuss whether bright and choked bursts are viable candidates. Our findings suggest that, although producing a copious neutrino flux, choked and bright astrophysical jets cannot be the dominant sources of the excess of neutrino events. A fine tuning of the model parameters or distinct scenarios for choked jets should be invoked in order to explain the low-energy neutrino data of IceCube and ANTARES.

THROUGH THE LOOKING GLASS: BRIGHT, HIGHLY MAGNIFIED GALAXY CANDIDATES AT z {approx} 7 BEHIND A1703

Energy Technology Data Exchange (ETDEWEB)

Bradley, L. D.; Coe, D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Bouwens, R. J.; Smit, R. [Leiden Observatory, Leiden University, Postbus 9513, 2300 RA Leiden (Netherlands); Zitrin, A. [School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Ford, H. C.; Zheng, W. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Illingworth, G. D. [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California Santa Cruz, Santa Cruz, CA 95064 (United States); Benitez, N. [Instituto de Astrofisica de Andalucia (CSIC), C/Camino Bajo de Huetor 24, Granada 18008 (Spain); Broadhurst, T. J. [Department of Theoretical Physics, University of Basque Country UPV/EHU, Leioa (Spain)

2012-03-01

We report the discovery of seven strongly lensed Lyman-break galaxy (LBG) candidates at z {approx} 7 detected in Hubble Space Telescope Wide Field Camera 3 (WFC3) imaging of A1703. The brightest candidate, called A1703-zD1, has an observed (lensed) magnitude of 24.0 AB (26{sigma}) in the WFC3/IR F160W band, making it 0.2 mag brighter than the z{sub 850}-dropout candidate recently reported behind the Bullet Cluster and 0.7 mag brighter than the previously brightest known z {approx} 7.6 galaxy, A1689-zD1. With a cluster magnification of {approx}9, this source has an intrinsic magnitude of H{sub 160} = 26.4 AB, a strong z{sub 850} - J{sub 125} break of 1.7 mag, and a photometric redshift of z {approx} 6.7. Additionally, we find six other bright LBG candidates with H{sub 160}-band magnitudes of 24.9-26.4, photometric redshifts z {approx} 6.4 - 8.8, and magnifications {mu} {approx} 3-40. Stellar population fits to the Advanced Camera for Surveys, WFC3/IR, and Spitzer/Infrared Array Camera data for A1703-zD1 and A1703-zD4 yield stellar masses (0.7 - 3.0) Multiplication-Sign 10{sup 9} M{sub Sun }, stellar ages 5-180 Myr, and star formation rates {approx}7.8 M{sub Sun} yr{sup -1}, and low reddening with A{sub V} {<=} 0.7. The source-plane reconstruction of the exceptionally bright candidate A1703-zD1 exhibits an extended structure, spanning {approx}4 kpc in the z {approx} 6.7 source plane, and shows three resolved star-forming knots of radius r {approx} 0.4 kpc.

Nasu 1.4 GHz Interferometer Transient Radio Source Survey and Improvement in Detection of Radio Sources

International Nuclear Information System (INIS)

Matsumura, Nobuo; Kuniyoshi, Masaya; Takefuji, Kazuhiro; Niinuma, Kotaro; Kida, Sumiko; Takeuchi, Akihiko; Asuma, Kuniyuki; Daishido, Tsuneaki

2006-01-01

We have surveyed 1.4GHz transient radio sources in Nasu Pulsar Observatory. To investigate such sources, both immediacy and accuracy are severely maintained. We have developed Data Transfer System and improved antenna control system. Now we have received the fringe data from transient radio source candidates. To get reliable information, we carefully analyze with Fringe Band Pass Filter software and Fringe Fitting method

Intermittent Episodes of Bright Light Suppress Myopia in the Chicken More than Continuous Bright Light

OpenAIRE

Lan, Weizhong; Feldkaemper, Marita; Schaeffel, Frank

2014-01-01

PURPOSE: Bright light has been shown a powerful inhibitor of myopia development in animal models. We studied which temporal patterns of bright light are the most potent in suppressing deprivation myopia in chickens. METHODS: Eight-day-old chickens wore diffusers over one eye to induce deprivation myopia. A reference group (n = 8) was kept under office-like illuminance (500 lux) at a 10:14 light:dark cycle. Episodes of bright light (15 000 lux) were super-imposed on this background as follows....

Optical Observations of X-ray Bright, Optically Normal Galaxies

Science.gov (United States)

Sadun, Alberto C.; Aryan, N. S.; Ghosh, K. K.

2007-05-01

X-ray bright, optically normal galaxies (XBONGs) are galaxies that seem to have normal spectra and morphology, but are relatively bright x-ray sources. The large ratio of the x-ray to optical emission suggests that some activity, similar to that of active galactic nuclei (AGN), is occurring. Since the galaxies do not show any obvious sign of nuclear activity in their optical spectra, one possible explanation is that these galaxies do not have an optically thick accretion disk at small radii, as previously assumed. Previous data for NGC 7626 classifies it as an XBONG, and so we are studying optical features of this galaxy in order to determine better its features. After confirming an x-ray jet, we are now comparing this to optical features that we have found, including warped dust lanes and a possible optical jet.

Bright luminance from silicon dioxide film with carbon nanotube electron beam exposure

Energy Technology Data Exchange (ETDEWEB)

Lee, Su Woong; Hong, Ji Hwan; Kang, Jung Su; Callixte, Shikili; Park, Kyu Chang, E-mail: kyupark@khu.ac.kr

2016-02-15

We observed the bright bluish-white luminescence with naked eye from carbon nanotube electron beam exposed silicon dioxide (SiO{sub 2}) thin film on Si substrate. The luminescence shows a peak intensity at 2.7 eV (460 nm) with wide spread up to 600 nm after the C-beam exposed on SiO{sub 2} thin film. The C-beam exposure system is composed of carbon nanotube emitters as electron beam source. The brightness strongly depend on the exposure condition. Luminescence characteristic was optimized by C-beam adjustment to observe with the naked eye. The cause of luminescence in the C-beam exposed SiO{sub 2} thin film is analyzed by CL microscopy, FT-IR, AFM and ellipsometer. Decrease of Si–O bonding was observed after C-beam exposure, and this reveals that oxygen deficient defects which are irradiation-sensitive cause 2.7 eV peak of luminescence. - Highlights: • We observed bright luminescence for SiO{sub 2} thin film with naked eye by carbon nanotube electron beam (C-beam) exposure technique. • The bright luminance from C-beam exposed SiO{sub 2} film will open novel silicon optoelectronics.

Survey of sources of manpower supply for the nuclear power industry

International Nuclear Information System (INIS)

1981-01-01

The following is a report of a survey designed to determine sources of manpower supply available to the Nuclear Power Industry. The survey is part of a larger research effort which is also designed to investigate occupational employment and training in the Nuclear Power Industry and competing sources of demand for technically qualified manpower. The results of those other studies have been published separately and are available upon request. This report includes a brief discussion of the background of the study, the research methods employed, the results obtained, and some implications of those findings. The appendices contain copies of the questionnaires used in the survey as well as some additional related data

THE REDSHIFT DISTRIBUTION OF GIANT ARCS IN THE SLOAN GIANT ARCS SURVEY

International Nuclear Information System (INIS)

Bayliss, Matthew B.; Gladders, Michael D.; Koester, Benjamin P.; Oguri, Masamune; Hennawi, Joseph F.; Sharon, Keren; Dahle, Haakon

2011-01-01

We measure the redshift distribution of a sample of 28 giant arcs discovered as a part of the Sloan Giant Arcs Survey. Gemini/GMOS-North spectroscopy provides precise redshifts for 24 arcs, and 'redshift desert' constrains for the remaining 4 arcs. This is a direct measurement of the redshift distribution of a uniformly selected sample of bright giant arcs, which is an observable that can be used to inform efforts to predict giant arc statistics. Our primary giant arc sample has a median redshift z = 1.821 and nearly two-thirds of the arcs, 64%, are sources at z ∼> 1.4, indicating that the population of background sources that are strongly lensed into bright giant arcs resides primarily at high redshift. We also analyze the distribution of redshifts for 19 secondary strongly lensed background sources that are not visually apparent in Sloan Digital Sky Survey imaging, but were identified in deeper follow-up imaging of the lensing cluster fields. Our redshift sample for the secondary sources is not spectroscopically complete, but combining it with our primary giant arc sample suggests that a large fraction of all background galaxies that are strongly lensed by foreground clusters reside at z ∼> 1.4. Kolmogorov-Smirnov tests indicate that our well-selected, spectroscopically complete primary giant arc redshift sample can be reproduced with a model distribution that is constructed from a combination of results from studies of strong-lensing clusters in numerical simulations and observational constraints on the galaxy luminosity function.

A PRECISION MULTI-BAND TWO-EPOCH PHOTOMETRIC CATALOG OF 44 MILLION SOURCES IN THE NORTHERN SKY FROM A COMBINATION OF THE USNO-B AND SLOAN DIGITAL SKY SURVEY CATALOGS

International Nuclear Information System (INIS)

Madsen, G. J.; Gaensler, B. M.

2013-01-01

A key science driver for the next generation of wide-field optical and radio surveys is the exploration of the time variable sky. These surveys will have unprecedented sensitivity and areal coverage, but will be limited in their ability to detect variability on time scales longer than the lifetime of the surveys. We present a new precision, multi-epoch photometric catalog that spans 60 yr by combining the US Naval Observatory-B (USNO-B) and Sloan Digital Sky Survey (SDSS) Data Release 9 (DR9) catalogs. We recalibrate the photometry of the original USNO-B catalog and create a catalog with two epochs of photometry in up to five different bands for 43,647,887 optical point sources that lie in the DR9 footprint of the northern sky. The recalibrated objects span a magnitude range 14 ≲ m ≲ 20 and are accurate to ≈0.1 mag. We minimize the presence of spurious objects and those with inaccurate magnitudes by identifying and removing several sources of systematic errors in the two originating catalogs, with a focus on spurious objects that exhibit large apparent magnitude variations. After accounting for these effects, we find ≈250,000 stars and quasars that show significant (≥4σ) changes in brightness between the USNO-B and SDSS DR9 epochs. We discuss the historical value of the catalog and its application to the study of long time scale, large amplitude variable stars and quasars

Entangling quantum-logic gate operated with an ultrabright semiconductor single-photon source.

Science.gov (United States)

Gazzano, O; Almeida, M P; Nowak, A K; Portalupi, S L; Lemaître, A; Sagnes, I; White, A G; Senellart, P

2013-06-21

We demonstrate the unambiguous entangling operation of a photonic quantum-logic gate driven by an ultrabright solid-state single-photon source. Indistinguishable single photons emitted by a single semiconductor quantum dot in a micropillar optical cavity are used as target and control qubits. For a source brightness of 0.56 photons per pulse, the measured truth table has an overlap with the ideal case of 68.4±0.5%, increasing to 73.0±1.6% for a source brightness of 0.17 photons per pulse. The gate is entangling: At a source brightness of 0.48, the Bell-state fidelity is above the entangling threshold of 50% and reaches 71.0±3.6% for a source brightness of 0.15.

Bright X-ray transient in the LMC

Science.gov (United States)

Saxton, R.; Read, A. M.; Li, D. Y.

2018-01-01

We report a bright X-ray transient in the LMC from an XMM-Newton slew made on 5th January 2018. The source, XMMSL2 J053629.4-675940, had a soft X-ray (0.2-2 keV) count rate in the EPIC-pn detector, medium filter of 1.82+/-0.56 c/s, equivalent to a flux Fx=2.3+/-0.7E-12 ergs/s/cm2 for a nominal spectrum of a power-law of slope 2 absorbed by a column NH=3E20 cm^-2.

(Almost) Dark Galaxies in the ALFALFA Survey: Isolated H i-bearing Ultra-diffuse Galaxies

Energy Technology Data Exchange (ETDEWEB)

Leisman, Lukas; Haynes, Martha P.; Giovanelli, Riccardo [Cornell Center for Astrophysics and Planetary Science, Space Sciences Building, Cornell University, Ithaca, NY 14853 (United States); Janowiecki, Steven [International Centre for Radio Astronomy Research (ICRAR), University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Hallenbeck, Gregory [Department of Physics and Astronomy, Union College, Schenectady, NY 12308 (United States); Józsa, Gyula [SKA South Africa Radio Astronomy Research Group, 3rd Floor, The Park, Park Road, Pinelands 7405 (South Africa); Adams, Elizabeth A. K. [ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA, Dwingeloo (Netherlands); Neira, David Bernal [Departamento de Física, Universidad de los Andes, Cra. 1 No. 18A-10, Edificio Ip, Bogotá (Colombia); Cannon, John M. [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Janesh, William F.; Rhode, Katherine L.; Salzer, John J. [Department of Astronomy, Indiana University, 727 East Third Street, Bloomington, IN 47405 (United States)

2017-06-20

We present a sample of 115 very low optical surface brightness, highly extended, H i-rich galaxies carefully selected from the ALFALFA survey that have similar optical absolute magnitudes, surface brightnesses, and radii to recently discovered “ultra-diffuse” galaxies (UDGs). However, these systems are bluer and have more irregular morphologies than other UDGs, are isolated, and contain significant reservoirs of H i. We find that while these sources have normal star formation rates for H i-selected galaxies of similar stellar mass, they have very low star formation efficiencies. We further present deep optical and H i-synthesis follow-up imaging of three of these H i-bearing ultra-diffuse sources. We measure H i diameters extending to ∼40 kpc, but note that while all three sources have large H i diameters for their stellar mass, they are consistent with the H i mass–H i radius relation. We further analyze the H i velocity widths and rotation velocities for the unresolved and resolved sources, respectively, and find that the sources appear to inhabit halos of dwarf galaxies. We estimate spin parameters, and suggest that these sources may exist in high spin parameter halos, and as such may be potential H i-rich progenitors to the ultra-diffuse galaxies observed in cluster environments.

BrightStat.com: free statistics online.

Science.gov (United States)

Stricker, Daniel

2008-10-01

Powerful software for statistical analysis is expensive. Here I present BrightStat, a statistical software running on the Internet which is free of charge. BrightStat's goals, its main capabilities and functionalities are outlined. Three different sample runs, a Friedman test, a chi-square test, and a step-wise multiple regression are presented. The results obtained by BrightStat are compared with results computed by SPSS, one of the global leader in providing statistical software, and VassarStats, a collection of scripts for data analysis running on the Internet. Elementary statistics is an inherent part of academic education and BrightStat is an alternative to commercial products.

Spectral Index Changes with Brightness for γ-Ray Loud Blazars J. H. ...

Indian Academy of Sciences (India)

spectral index changes depending on γ-ray brightness is obtained. ... the γ-ray band. Key words. Active galactic nuclei (AGN): blazars: γ-ray emission: spectral index. 1. Introduction. Generally, the spectrum of one source changes with its .... Pearl River Scholar Funded Scheme (GDUPS) (2009), Yangcheng Scholar Funded.

High-brightness electron beams for production of high intensity, coherent radiation for scientific and industrial applications

International Nuclear Information System (INIS)

Kim, K.-J.

1999-01-01

Relativistic electron beams with high six-dimensional phase space densities, i.e., high-brightness beams, are the basis for efficient generation of intense and coherent radiation beams for advanced scientific and industrial applications. The remarkable progress in synchrotrons radiation facilities from the first generation to the current, third-generation capability illustrates this point. With the recent development of the high-brightness electron gun based on laser-driven rf photocathodes, linacs have become another important option for high-brightness electron beams. With linacs of about 100 MeV, megawatt-class infrared free-electron lasers can be designed for industrial applications such as power beaming. With linacs of about 10 GeV, 1- angstrom x-ray beams with brightness and time resolution exceeding by several orders of magnitude the current synchrotrons radiation sources can be generated based on self-amplified spontaneous emission. Scattering of a high-brightness electron beam by high power laser beams is emerging as a compact method of generating short-pulse, bright x-rays. In the high-energy frontier, photons of TeV quantum energy could be generated by scattering laser beams with TeV electron beams in future linear colliders

Working group II report: Production and dynamics of high brightness beams

International Nuclear Information System (INIS)

Sheffield, R.L.

1996-01-01

This paper summarizes the main discussions of the Working Group on the Production and Dynamics of High Brightness Beams. The following topics are covered in this paper. Proposed new electron sources and needed research on existing sources is covered. The discussions on issues relating to the description of phase space on non-thermalized electron beam distributions and the theoretical modeling on non-thermalized electron beam distributions is presented. Finally, the present status of the theoretical modeling of beam transport in bends is given

ROLE OF DIAMOND SECONDARY EMITTERS IN HIGH BRIGHTNESS ELECTRON SOURCES

International Nuclear Information System (INIS)

2005-01-01

In this paper we explore the possibility of using diamond secondary emitter in a high average current electron injector to amplify the current from the photocathode and to isolate the cathode and the injector from each other to increase the life time of the cathode and preserve the performance of the injector. Secondary electron yield of 225 and current density of 0.8 a/cm 2 have been measured in the transmission mode from type 2 a natural diamond. Although the diamond will be heated during normal operation in the injector, calculations indicate that by cryogenically cooling the diamond, the temperature gradient along the diamond can be maintained within the acceptable range. The electron energy and temporal distributions are expected to be narrow from this device resulting in high brightness beams. Plans are underway to measure the SEY in emission mode, fabricate photocathode-diamond capsule and test diamond and capsule in superconducting RF injector

Brightness and transparency in the early visual cortex.

Science.gov (United States)

Salmela, Viljami R; Vanni, Simo

2013-06-24

Several psychophysical studies have shown that transparency can have drastic effects on brightness and lightness. However, the neural processes generating these effects have remained unresolved. Several lines of evidence suggest that the early visual cortex is important for brightness perception. While single cell recordings suggest that surface brightness is represented in the primary visual cortex, the results of functional magnetic resonance imaging (fMRI) studies have been discrepant. In addition, the location of the neural representation of transparency is not yet known. We investigated whether the fMRI responses in areas V1, V2, and V3 correlate with brightness and transparency. To dissociate the blood oxygen level-dependent (BOLD) response to brightness from the response to local border contrast and mean luminance, we used variants of White's brightness illusion, both opaque and transparent, in which luminance increments and decrements cancel each other out. The stimuli consisted of a target surface and a surround. The surround luminance was always sinusoidally modulated at 0.5 Hz to induce brightness modulation to the target. The target luminance was constant or modulated in counterphase to null brightness modulation. The mean signal changes were calculated from the voxels in V1, V2, and V3 corresponding to the retinotopic location of the target surface. The BOLD responses were significantly stronger for modulating brightness than for stimuli with constant brightness. In addition, the responses were stronger for transparent than for opaque stimuli, but there was more individual variation. No interaction between brightness and transparency was found. The results show that the early visual areas V1-V3 are sensitive to surface brightness and transparency and suggest that brightness and transparency are represented separately.

A radio monitoring survey of ultra-luminous X-ray sources

Science.gov (United States)

Körding, E.; Colbert, E.; Falcke, H.

2005-06-01

We present the results of a radio monitoring campaign to search for radio emission from nearby ultra-luminous X-ray sources (ULXs). These sources are bright off-nuclear X-ray point sources with luminosities exceeding LX > 1039 erg s-1. A well-defined sample of the 9 nearest ULXs has been monitored eight times over 5 months with the Very Large Array in A and B configuration. Our limiting sensitivity is ≈0.15 mJy (4σ) for radio flares and ≈60 μJy for continuous emission. In M 82 two ULXs seem to have coincident compact radio sources, which are probably supernova remnants. No continuous or flaring radio emission has been detected from any other ULX. Thus, ULXs do not generally emit steady-state radio emission above radio powers of 1.5 × 1017 W/Hz. The non-detections of the continuous emission are consistent with beamed or unbeamed radio emission from accreting black holes of ≤ 103 M⊙ based on the radio/X-ray correlation. Other published radio detections (M 82, NGC 5408) are also discussed in this context. Both detections are significantly above our detection limit. If ULXs have flaring radio emission above 4 × 1017 W/Hz we can give an upper limit on the duty cycle of the flares of 6%. This upper limit is in agreement with the observed number of flares in Galactic radio transients. Additionally we present a yet unreported radio double structure in the nearby low-luminosity AGN NGC 4736.

A radio/infrared/optical study of candidate supernova remnants from the Clark Lake 30.9 MHz Galactic plane survey

International Nuclear Information System (INIS)

Gorham, P.W.

1990-01-01

In this paper, it is shown that more than half of the SNR candidates from the first Galactic quadrant in the Clark Lake 30.9 MHz survey show independent evidence of being associated with SNRs. In most cases, these appear to be low surface brightness SNRs which have escaped detection in the past. About a fifth of the candidates should be strongly considered for classification as new SNRs, and a third of these are also probable IR sources, consistent with the detected fraction of known Galactic SNRs seen in a recent IR survey. Two of the confirmed candidates share the characteristic of appearing considerably larger at 30.9 MHz than they do at centimeter or optical wavelengths. This characteristic suggests the possibility of extended, low surface brightness emission that may extend considerably beyond the nominal boundaries of some SNRs. 27 refs

Record productions establish RF-driven sources as the standard for generating high-duty-factor, high-current H- beams for accelerators (Winner of the ICIS 2017 Brightness Award)

Science.gov (United States)

Stockli, Martin P.; Welton, Robert F.; Han, Baoxi

2018-05-01

The Spallation Neutron Source operates reliably at 1.2 MW and will gradually ramp to 1.4 MW. This paper briefly recalls some of the struggles when the unprecedented project was started and ramped to 1 MW over a 3½ year period. This was challenging, especially for the H- ion source and the low-energy beam transport system, which make up the H- injector. It took several more years to push the H- injector to the 1.4 MW requirements, and even longer to reach close to 100% injector availability. An additional breakthrough was the carefully staged, successful extension of the H- source service cycle so that disruptive source changes became rare events. More than 7 A.h of extracted H- ions have been demonstrated with a single source without maintenance, more than twice the single-source quantity of ions produced by any other high-current H- accelerator facility. Achieving the 1.4 MW requirements with close to 100% availability and record-breaking source service cycles were the basis for the 2017 Brightness Award.

A survey of open source tools for business intelligence

DEFF Research Database (Denmark)

Thomsen, Christian; Pedersen, Torben Bach

2005-01-01

The industrial use of open source Business Intelligence (BI) tools is not yet common. It is therefore of interest to explore which possibilities are available for open source BI and compare the tools. In this survey paper, we consider the capabilities of a number of open source tools for BI....... In the paper, we consider three Extract-Transform-Load (ETL) tools, three On-Line Analytical Processing (OLAP) servers, two OLAP clients, and four database management systems (DBMSs). Further, we describe the licenses that the products are released under. It is argued that the ETL tools are still not very...

143 GHz BRIGHTNESS MEASUREMENTS OF URANUS, NEPTUNE, AND OTHER SECONDARY CALIBRATORS WITH BOLOCAM BETWEEN 2003 AND 2010

International Nuclear Information System (INIS)

Sayers, J.; Czakon, N. G.; Golwala, S. R.

2012-01-01

Bolocam began collecting science data in 2003 as the long-wavelength imaging camera at the Caltech Submillimeter Observatory. The planets, along with a handful of secondary calibrators, have been used to determine the flux calibration for all of the data collected with Bolocam. Uranus and Neptune stand out as the only two planets that are bright enough to be seen with high signal-to-noise in short integrations without saturating the standard Bolocam readout electronics. By analyzing all of the 143 GHz observations made with Bolocam between 2003 and 2010, we find that the brightness ratio of Uranus to Neptune is 1.027 ± 0.006, with no evidence for any variations over that period. Including previously published results at ≅ 150 GHz, we find a brightness ratio of 1.029 ± 0.006 with no evidence for time variability over the period 1983-2010. Additionally, we find no evidence for time variability in the brightness ratio of either Uranus or Neptune to the ultracompact H II region G34.3 or the protostellar source NGC 2071IR. Using recently published Wilkinson Microwave Anisotropy Probe results we constrain the absolute 143 GHz brightness of both Uranus and Neptune to ≅ 3%. Finally, we present ≅ 3% absolute 143 GHz peak flux density values for the ultracompact H II regions G34.3 and K3-50A and the protostellar source NGC 2071IR.

An Ultra-Bright Pulsed Electron Beam with Low Longitudinal Emittance

CERN Document Server

Zolotorev, Max S; Denes, Peter; Heifets, Samuel; Hussain, Zahid; Lebedev, Gennadi; Lidia, Steven M; Robin, David; Sannibale, Fernando; Schönlein, Robert W; Vogel, Robert; Wan, Weishi

2005-01-01

We describe a novel scheme for an electron source in the 10 - 100 eV range with the capability of approaching the brightness quantum-limit and of lowering the effective temperature of the electrons orders of magnitude with respect to existing sources. Such a device can open the way for a wide range of novel applications that utilize angstrom-scale spatial resolution and ?eV-scale energy resolution. Possible examples include electron microscopy, electron holography, and investigations of dynamics on a picosecond time scale using pump-probe techniques. In this paper we describe the concepts for such a source including a complete and consistent set of parameters for the construction of a real device based on the presented scheme.

Bright PanSTARRS Nuclear Transients – what are they?

Directory of Open Access Journals (Sweden)

Smartt S.

2012-12-01

Full Text Available We present an initial analysis of 49 bright transients occurring in the nuclei of galaxies with no previous known Active Galactic Nucleus (AGN. They have been discovered as part of the PanSTARRs 3π survey, and followed up with the Liverpool Telescope. Based on colours, light curve shape, and a small number with optical spectra, these transients seem to fall into three groups. Red/fast transients are nuclear supernovae of various types. Some bright nuclear transients are blue and decay on a timescale of a few months; these may be candidates for tidal disruption events. However most of the events we have found are blue and are either still rising or decaying slowly, on a timescale of years; the few spectra we have show AGN at z ∼ 1. We argue that these transients are background AGN microlensed by stars in foreground galaxies by a factor 10–100. Monitoring such events gives us very promising prospects for measuring the structure of AGN and so testing current theories.

VizieR Online Data Catalog: IR-bright MSX sources in the SMC with Spitzer/IRS (Kraemer+, 2017)

Science.gov (United States)

Kraemer, K. E.; Sloan, G. C.; Wood, P. R.; Jones, O. C.; Egan, M. P.

2017-07-01

Our original set of infrared spectra of MSX SMC sources was obtained in Spitzer Cycle 1 (Program ID 3277, P.I. M. Egan). This program included 35 targets from the MSX SMC catalog. 24 targets were discussed in previous papers; this paper examines the remaining 11 sources in the sample. We also selected 4 objects in the MSX SMC catalog with similar photometric characteristics in an effort to uncover additional sources with crystalline dust. We observed these targets in Spitzer Cycle 3 (Program ID 30355, P.I. J. Houck). See tables 1 and 2 for observation data and basic properties of the targets. Table 3 lists 20 additional MSX SMC sources that were observed by other Spitzer IRS programs. Overall, 59 MSX SMC sources were observed with the IRS. The spectra were observed using the low-resolution modules of the IRS, Short-Low (SL) and Long-Low (LL), which provided spectra in the 5-14 and 14-37um ranges, respectively, at a resolution between ~60 and 120. For 10 evolved stars with oxygen-rich dust in our Cycle 1 program, we obtained spectra from 0.45 to 1.03um with the Double-Beam Spectrograph at the 2.3m telescope of the Australian National University at Siding Spring Observatory. A 0.45-0.89um spectrum for one of the stars in program 30355 was also observed. These spectra have a resolution of 10Å. Tables 5-7: catalog based on the 243 sources detected in the MSX survey of the SMC, updated with positions and photometry from more recent space-based missions and ground-based surveys. See the Appendix section for more details. The SMC catalog from MSX consists of the 243 sources in the main MSX catalog (Egan+ 2003, see V/114) that lie within the region 7°

Does low surface brightness mean low density?

NARCIS (Netherlands)

deBlok, WJG; McGaugh, SS

1996-01-01

We compare the dynamical properties of two galaxies at identical positions on the Tully-Fisher relation, but with different surface brightnesses. We find that the low surface brightness galaxy UGC 128 has a higher mass-to-light ratio, and yet has lower mass densities than the high surface brightness

The optical spectra of 24 mu m galaxies in the cosmos field. I. Spitzer MIPS bright sources in the zCOSMOS-bright 10k catalog

NARCIS (Netherlands)

Caputi, K. I.; Lilly, S. J.; Aussel, H.; Sanders, D.; Frayer, D.; Le Fevre, O.; Renzini, A.; Zamorani, G.; Scodeggio, M.; Contini, T.; Scoville, N.; Carollo, C. M.; Hasinger, G.; Iovino, A.; Le Brun, V.; Le Floc'h, E.; Maier, C.; Mainieri, V.; Mignoli, M.; Salvato, M.; Schiminovich, D.; Silverman, J.; Surace, J.; Tasca, L.; Abbas, U.; Bardelli, S.; Bolzonella, M.; Bongiorno, A.; Bottini, D.; Capak, P.; Cappi, A.; Cassata, P.; Cimatti, A.; Cucciati, O.; de la Torre, S.; de Ravel, L.; Franzetti, P.; Fumana, M.; Garilli, B.; Halliday, C.; Ilbert, O.; Kampczyk, P.; Kartaltepe, J.; Kneib, J. -P.; Knobel, C.; Kovac, K.; Lamareille, F.; Leauthaud, A.; Le Borgne, J. F.; Maccagni, D.; Marinoni, C.; McCracken, H.; Meneux, B.; Oesch, P.; Pello, R.; Perez-Montero, E.; Porciani, C.; Ricciardelli, E.; Scaramella, R.; Scarlata, C.; Tresse, L.; Vergani, D.; Walcher, J.; Zamojski, M.; Zucca, E.

2008-01-01

We study zCOSMOS-bright optical spectra for 609 Spitzer MIPS 24 mu m-selected galaxies with S-24 (mu m) > 0: 30 mJy and I <22.5 (AB mag) over 1.5 deg(2) of the COSMOS field. From emission-line diagnostics we find the following: (1) SFRs derived from the observed H alpha lambda 6563 and H beta lambda

A survey of open source multiphysics frameworks in engineering

NARCIS (Netherlands)

Babur, O.; Smilauer, V.; Verhoeff, T.; Brand, van den M.G.J.

2015-01-01

This paper presents a systematic survey of open source multiphysics frameworks in the en- gineering domains. These domains share many commonalities despite the diverse application areas. A thorough search for the available frameworks with both academic and industrial ori- gins has revealed numerous

SEDS: THE SPITZER EXTENDED DEEP SURVEY. SURVEY DESIGN, PHOTOMETRY, AND DEEP IRAC SOURCE COUNTS

International Nuclear Information System (INIS)

Ashby, M. L. N.; Willner, S. P.; Fazio, G. G.; Huang, J.-S.; Hernquist, L.; Hora, J. L.; Arendt, R.; Barmby, P.; Barro, G.; Faber, S.; Guhathakurta, P.; Bell, E. F.; Bouwens, R.; Cattaneo, A.; Croton, D.; Davé, R.; Dunlop, J. S.; Egami, E.; Finlator, K.; Grogin, N. A.

2013-01-01

The Spitzer Extended Deep Survey (SEDS) is a very deep infrared survey within five well-known extragalactic science fields: the UKIDSS Ultra-Deep Survey, the Extended Chandra Deep Field South, COSMOS, the Hubble Deep Field North, and the Extended Groth Strip. SEDS covers a total area of 1.46 deg 2 to a depth of 26 AB mag (3σ) in both of the warm Infrared Array Camera (IRAC) bands at 3.6 and 4.5 μm. Because of its uniform depth of coverage in so many widely-separated fields, SEDS is subject to roughly 25% smaller errors due to cosmic variance than a single-field survey of the same size. SEDS was designed to detect and characterize galaxies from intermediate to high redshifts (z = 2-7) with a built-in means of assessing the impact of cosmic variance on the individual fields. Because the full SEDS depth was accumulated in at least three separate visits to each field, typically with six-month intervals between visits, SEDS also furnishes an opportunity to assess the infrared variability of faint objects. This paper describes the SEDS survey design, processing, and publicly-available data products. Deep IRAC counts for the more than 300,000 galaxies detected by SEDS are consistent with models based on known galaxy populations. Discrete IRAC sources contribute 5.6 ± 1.0 and 4.4 ± 0.8 nW m –2 sr –1 at 3.6 and 4.5 μm to the diffuse cosmic infrared background (CIB). IRAC sources cannot contribute more than half of the total CIB flux estimated from DIRBE data. Barring an unexpected error in the DIRBE flux estimates, half the CIB flux must therefore come from a diffuse component.

The European large area ISO survey - III. 90-mu m extragalactic source counts

DEFF Research Database (Denmark)

Efstathiou, A.; Oliver, S.; Rowan-Robinson, M.

2000-01-01

We present results and source counts at 90 mum extracted from the preliminary analysis of the European Large Area ISO Survey (ELAIS). The survey covered about 12 deg(2) of the sky in four main areas and was carried out with the ISOPHOT instrument onboard the Infrared Space Observatory (ISO...... or small groups of galaxies, suggesting that the sample may include a significant fraction of luminous infrared galaxies. The source counts extracted from a reliable subset of the detected sources are in agreement with strongly evolving models of the starburst galaxy population....

Uncovering extreme AGN variability in serendipitous X-ray source surveys

Science.gov (United States)

Moran, Edward C.; Garcia Soto, Aylin; LaMassa, Stephanie; Urry, Meg

2018-01-01

Constraints on the duty cycle and duration of accretion episodes in active galactic nuclei (AGNs) are vital for establishing how most AGNs are fueled, which is essential for a complete picture of black hole/galaxy co-evolution. Perhaps the best handle we have on these activity parameters is provided by AGNs that have displayed dramatic changes in their bolometric luminosities and, in some cases, spectroscopic classifications. Given that X-ray emission is directly linked to black-hole accretion, X-ray surveys should provide a straightforward means of identifying AGNs that have undergone dramatic changes in their accretion states. However, it appears that such events are very rare, so wide-area surveys separated in time by many years are needed to maximize discovery rates. We have cross-correlated the Einstein IPC Two-Sigma Catalog with the ROSAT All-Sky Survey Faint Source Catalog to identify a sample of soft X-ray sources that varied by factors ranging from 7 to more than 100 over a ten year timescale. When possible, we have constructed long-term X-ray light curves for the sources by combining the Einstein and RASS fluxes with those obtained from serendipitous pointed observations by ROSAT, Chandra,XMM, and Swift. Optical follow-up observations indicate that many of the extremely variable sources in our sample are indeed radio-quiet AGNs. Interestingly, the majority of objects that dimmed between ~1980 and ~1990 are still (or are again) broad-line AGNs rather than“changing-look” candidates that have more subtle AGN signatures in their spectra — despite the fact that none of the sources examined thus far has returned to its highest observed luminosity. Future X-ray observations will provide the opportunity to characterize the X-ray behavior of these anonymous, extreme AGNs over a four decade span.

Electromagnetically induced transparency control in terahertz metasurfaces based on bright-bright mode coupling

Science.gov (United States)

Yahiaoui, R.; Burrow, J. A.; Mekonen, S. M.; Sarangan, A.; Mathews, J.; Agha, I.; Searles, T. A.

2018-04-01

We demonstrate a classical analog of electromagnetically induced transparency (EIT) in a highly flexible planar terahertz metamaterial (MM) comprised of three-gap split-ring resonators. The keys to achieve EIT in this system are the frequency detuning and hybridization processes between two bright modes coexisting in the same unit cell as opposed to bright-dark modes. We present experimental verification of two bright modes coupling for a terahertz EIT-MM in the context of numerical results and theoretical analysis based on a coupled Lorentz oscillator model. In addition, a hybrid variation of the EIT-MM is proposed and implemented numerically to dynamically tune the EIT window by incorporating photosensitive silicon pads in the split gap region of the resonators. As a result, this hybrid MM enables the active optical control of a transition from the on state (EIT mode) to the off state (dipole mode).

NIGHT SKY BRIGHTNESS ABOVE ZAGREB 2012.-2017.

Directory of Open Access Journals (Sweden)

Željko Andreić

2018-01-01

Full Text Available The night sky brightness at the RGN site (near the centre of Zagreb, Croatia was monitored form January 2012. to December 2017. The gathered data show that the average night sky brightness in this period did not change significantly, apart from differences caused by yearly variations in meteorological parameters. The nightly minima, maxima and mean values of the sky brightness do change considerably due to changes in meteorological conditions, often being between 2 and 3 magnitudes. The seasonal probability curves and histograms are constructed and are used to obtain additional information on the light pollution at the RGN site. They reveal that the night sky brightness clutters around two peaks, at about 15.0 mag/arcsec2 and at about 18.2 mag/arcsec2. The tendency to slightly lower brightness values in spring and summer can also be seen in the data. Two peaks correspond to cloudy and clear nights respectively, the difference in brightness between them being about 3 magnitudes. A crude clear/cloudy criterion can be defined too: the minimum between two peaks is around 16.7 mag/arcsec2. The brightness values smaller than thisare attributed to clear nights and vice-versa. Comparison with Vienna and Hong-Kong indicates that the light pollution of Zagreb is a few times larger.

SOLAR CYCLE VARIATIONS OF THE RADIO BRIGHTNESS OF THE SOLAR POLAR REGIONS AS OBSERVED BY THE NOBEYAMA RADIOHELIOGRAPH

Energy Technology Data Exchange (ETDEWEB)

Nitta, Nariaki V.; DeRosa, Marc L. [Lockheed Martin Advanced Technology Center, Dept/A021S, B/252, 3251 Hanover Street, Palo Alto, CA 94304 (United States); Sun, Xudong; Hoeksema, J. Todd [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

2014-01-10

We have analyzed daily microwave images of the Sun at 17 GHz obtained with the Nobeyama Radioheliograph (NoRH) in order to study the solar cycle variations of the enhanced brightness in the polar regions. Unlike in previous works, the averaged brightness of the polar regions is obtained from individual images rather than from synoptic maps. We confirm that the brightness is anti-correlated with the solar cycle and that it has generally declined since solar cycle 22. Including images up to 2013 October, we find that the 17 GHz brightness temperature of the south polar region has decreased noticeably since 2012. This coincides with a significant decrease in the average magnetic field strength around the south pole, signaling the arrival of solar maximum conditions in the southern hemisphere more than a year after the northern hemisphere. We do not attribute the enhanced brightness of the polar regions at 17 GHz to the bright compact sources that occasionally appear in synthesized NoRH images. This is because they have no correspondence with small-scale bright regions in images from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory with a broad temperature coverage. Higher-quality radio images are needed to understand the relationship between microwave brightness and magnetic field strength in the polar regions.

Linking optical and infrared observations with gravitational wave sources through transient variability

International Nuclear Information System (INIS)

Stubbs, C W

2008-01-01

Optical and infrared observations have thus far detected more celestial cataclysms than have been seen in gravity waves (GW). This argues that we should search for gravity wave signatures that correspond to transient variables seen at optical wavelengths, at precisely known positions. There is an unknown time delay between the optical and gravitational transient, but knowing the source location precisely specifies the corresponding time delays across the gravitational antenna network as a function of the GW-to-optical arrival time difference. Optical searches should detect virtually all supernovae that are plausible gravitational radiation sources. The transient optical signature expected from merging compact objects is not as well understood, but there are good reasons to expect detectable transient optical/IR emission from most of these sources as well. The next generation of deep wide-field surveys (for example PanSTARRS and LSST) will be sensitive to subtle optical variability, but we need to fill the 'blind spots' that exist in the galactic plane, and for optically bright transient sources. In particular, a galactic plane variability survey at λ∼ 2 μm seems worthwhile. Science would benefit from closer coordination between the various optical survey projects and the gravity wave community

SHARDS: Survey for High-z Absorption Red & Dead Sources

Science.gov (United States)

Pérez-González, P. G.; Cava, A.

2013-05-01

SHARDS, an ESO/GTC Large Program, is an ultra-deep (26.5 mag) spectro-photometric survey with GTC/OSIRIS designed to select and study massive passively evolving galaxies at z=1.0-2.3 in the GOODS-N field using a set of 24 medium-band filters (FWHM~17 nm) covering the 500-950 nm spectral range. Our observing strategy has been planned to detect, for z>1 sources, the prominent Mg absorption feature (at rest-frame ~280 nm), a distinctive, necessary, and sufficient feature of evolved stellar populations (older than 0.5 Gyr). These observations are being used to: (1) derive for the first time an unbiased sample of high-z quiescent galaxies, which extends to fainter magnitudes the samples selected with color techniques and spectroscopic surveys; (2) derive accurate ages and stellar masses based on robust measurements of spectral features such as the Mg_UV or D(4000) indices; (3) measure their redshift with an accuracy Δz/(1+z)<0.02; and (4) study emission-line galaxies (starbursts and AGN) up to very high redshifts. The well-sampled optical SEDs provided by SHARDS for all sources in the GOODS-N field are a valuable complement for current and future surveys carried out with other telescopes (e.g., Spitzer, HST, and Herschel).

The Advanced Light Source Upgrade

International Nuclear Information System (INIS)

Chemla, Daniel S.; Feinberg, Benjamin; Hussain, Zahid; Krebs, Gary F.; Padmore, Howard A.; Robin, David S.; Robinson, Arthur L.; Smith, Neville V.

2003-01-01

The ALS, a third-generation synchrotron light source at Berkeley Lab, has been operating for almost a decade and is generating forefront science by exploiting the high brightness of a third-generation source in three areas: (1) high resolving power for spectroscopy; (2) high spatial resolution for microscopy and spectromicroscopy; and (3) high coherence for experiments such as speckle. However, the ALS was one of the first third-generation machines to be designed, and accelerator and insertion-device technology have significantly changed since its conception. As a result, its performance will inevitably be outstripped by newer, more advanced sources. To remain competitive and then set a new standard, the performance of the ALS, in particular its brightness, must be enhanced. Substantial improvements in brightness and current have always been feasible in principle, but they incur the penalty of a much reduced lifetime, which is totally unacceptable to our users. Significant brightness improvements can be realized in the core soft x-ray region by going to top-off operation, where injection would be quasi-continuous and the lifetime objections disappear. In top-off mode with higher average current, a reduced vertical emittance and beta function, and small-gap permanent-magnet or superconducting insertion devices, one to two orders of magnitude improvement in brightness can be had in the soft x-ray range. These improvements also extend the high energy range of the undulator radiation beyond the current limit of 2000 eV. Descriptions of the upgrade and the important new science achievable are presented

Forward Global Photometric Calibration of the Dark Energy Survey

Science.gov (United States)

Burke, D. L.; Rykoff, E. S.; Allam, S.; Annis, J.; Bechtol, K.; Bernstein, G. M.; Drlica-Wagner, A.; Finley, D. A.; Gruendl, R. A.; James, D. J.; Kent, S.; Kessler, R.; Kuhlmann, S.; Lasker, J.; Li, T. S.; Scolnic, D.; Smith, J.; Tucker, D. L.; Wester, W.; Yanny, B.; Abbott, T. M. C.; Abdalla, F. B.; Benoit-Lévy, A.; Bertin, E.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Cunha, C. E.; D’Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; García-Bellido, J.; Gruen, D.; Gutierrez, G.; Honscheid, K.; Kuehn, K.; Kuropatkin, N.; Maia, M. A. G.; March, M.; Marshall, J. L.; Melchior, P.; Menanteau, F.; Miquel, R.; Plazas, A. A.; Sako, M.; Sanchez, E.; Scarpine, V.; Schindler, R.; Sevilla-Noarbe, I.; Smith, M.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Tarle, G.; Walker, A. R.; DES Collaboration

2018-01-01

Many scientific goals for the Dark Energy Survey (DES) require the calibration of optical/NIR broadband b = grizY photometry that is stable in time and uniform over the celestial sky to one percent or better. It is also necessary to limit to similar accuracy systematic uncertainty in the calibrated broadband magnitudes due to uncertainty in the spectrum of the source. Here we present a “Forward Global Calibration Method (FGCM)” for photometric calibration of the DES, and we present results of its application to the first three years of the survey (Y3A1). The FGCM combines data taken with auxiliary instrumentation at the observatory with data from the broadband survey imaging itself and models of the instrument and atmosphere to estimate the spatial and time dependences of the passbands of individual DES survey exposures. “Standard” passbands that are typical of the passbands encountered during the survey are chosen. The passband of any individual observation is combined with an estimate of the source spectral shape to yield a magnitude {m}b{std} in the standard system. This “chromatic correction” to the standard system is necessary to achieve subpercent calibrations and in particular, to resolve ambiguity between the broadband brightness of a source and the shape of its SED. The FGCM achieves a reproducible and stable photometric calibration of standard magnitudes {m}b{std} of stellar sources over the multiyear Y3A1 data sample with residual random calibration errors of σ =6{--}7 {mmag} per exposure. The accuracy of the calibration is uniform across the 5000 {\\deg }2 DES footprint to within σ =7 {mmag}. The systematic uncertainties of magnitudes in the standard system due to the spectra of sources are less than 5 {mmag} for main-sequence stars with 0.5< g-i< 3.0.

Teradiode's high brightness semiconductor lasers

Science.gov (United States)

Huang, Robin K.; Chann, Bien; Burgess, James; Lochman, Bryan; Zhou, Wang; Cruz, Mike; Cook, Rob; Dugmore, Dan; Shattuck, Jeff; Tayebati, Parviz

2016-03-01

TeraDiode is manufacturing multi-kW-class ultra-high brightness fiber-coupled direct diode lasers for industrial applications. A fiber-coupled direct diode laser with a power level of 4,680 W from a 100 μm core diameter, BPP) of 3.5 mm-mrad and is the lowest BPP multi-kW-class direct diode laser yet reported. This laser is suitable for industrial materials processing applications, including sheet metal cutting and welding. This 4-kW fiber-coupled direct diode laser has comparable brightness to that of industrial fiber lasers and CO2 lasers, and is over 10x brighter than state-of-the-art direct diode lasers. We have also demonstrated novel high peak power lasers and high brightness Mid-Infrared Lasers.

The Feasibility of Using the BrightHearts Biofeedback-Assisted Relaxation Application for the Management of Pediatric Procedural Pain: A Pilot Study.

Science.gov (United States)

Burton, Karen L O; Morrow, Angela M; Beswick, Brooke V; Khut, George P

2018-04-17

The objective of this pilot study was to assess the acceptability and feasibility of using BrightHearts, a biofeedback-assisted relaxation application (app), in children undergoing painful procedures. Thirty children 7 to 18 years of age undergoing a medical procedure (peripheral blood collection, botulinum toxin injection, or intravenous cannula insertion) participated. Participants used BrightHearts, a heart rate-controlled biofeedback-assisted relaxation training app delivered via an iPad with heart rate measured through a pulse oximeter worn on the ear or thumb. Feasibility was assessed through observations and patient, parent/carer, and healthcare professional feedback. Patient, parent/carer, and healthcare professional satisfaction with BrightHearts was rated using investigator-developed surveys. Eighty-three percent of child participants reported that they found BrightHearts helpful during the procedure and that they would use BrightHearts again. All parents and 96% of healthcare professionals indicated they would use BrightHearts again. Sixty-four percent of healthcare providers perceived that BrightHearts assisted with the ease of performing the procedure. Qualitative analyses found 2 themes: (1) BrightHearts calms through providing distraction and biofeedback and (2) the impact of BrightHearts on the procedure. This pilot study demonstrates the feasibility of using biofeedback-assisted relaxation delivered via the BrightHearts app in children undergoing peripheral blood collection and cannulation. Future studies are required to evaluate BrightHearts' efficacy in reducing pain and anxiety during painful procedures and distinguish the effects of a biofeedback-mediated app from distraction. © 2018 World Institute of Pain.

A Silicon-Chip Source of Bright Photon-Pair Comb

Science.gov (United States)

2012-10-16

quantum light sources. Nature Photon. 1, 215 (2007). 14 Kwait, P. G., Mattle, K., Weinfurter, H., & Zeilinger , A. New High-Intensity Source of...Jennewein, T., & Zeilinger , A. A wavelength-tunable fiber-coupled 26 source of narrowband entangled photons. Opt. Express 15, 15377 (2007). 18 Chen...Lett. 101, 051108 (2012). 47 Ramelow, S., Ratschbacher, L., Fedrizzi, A., Langford, N. K., & Zeilinger , A. Discrete tunable color entanglement. Phys

The Variability of Atmospheric Deuterium Brightness at Mars: Evidence for Seasonal Dependence

Science.gov (United States)

Mayyasi, Majd; Clarke, John; Bhattacharyya, Dolon; Deighan, Justin; Jain, Sonal; Chaffin, Michael; Thiemann, Edward; Schneider, Nick; Jakosky, Bruce

2017-10-01

The enhanced ratio of deuterium to hydrogen on Mars has been widely interpreted as indicating the loss of a large column of water into space, and the hydrogen content of the upper atmosphere is now known to be highly variable. The variation in the properties of both deuterium and hydrogen in the upper atmosphere of Mars is indicative of the dynamical processes that produce these species and propagate them to altitudes where they can escape the planet. Understanding the seasonal variability of D is key to understanding the variability of the escape rate of water from Mars. Data from a 15 month observing campaign, made by the Mars Atmosphere and Volatile Evolution Imaging Ultraviolet Spectrograph high-resolution echelle channel, are used to determine the brightness of deuterium as observed at the limb of Mars. The D emission is highly variable, with a peak in brightness just after southern summer solstice. The trends of D brightness are examined against extrinsic as well as intrinsic sources. It is found that the fluctuations in deuterium brightness in the upper atmosphere of Mars (up to 400 km), corrected for periodic solar variations, vary on timescales that are similar to those of water vapor fluctuations lower in the atmosphere (20-80 km). The observed variability in deuterium may be attributed to seasonal factors such as regional dust storm activity and subsequent circulation lower in the atmosphere.

High spatial resolution and high brightness ion beam probe for in-situ elemental and isotopic analysis

Science.gov (United States)

Long, Tao; Clement, Stephen W. J.; Bao, Zemin; Wang, Peizhi; Tian, Di; Liu, Dunyi

2018-03-01

A high spatial resolution and high brightness ion beam from a cold cathode duoplasmatron source and primary ion optics are presented and applied to in-situ analysis of micro-scale geological material with complex structural and chemical features. The magnetic field in the source as well as the influence of relative permeability of magnetic materials on source performance was simulated using COMSOL to confirm the magnetic field strength of the source. Based on SIMION simulation, a high brightness and high spatial resolution negative ion optical system has been developed to achieve Critical (Gaussian) illumination mode. The ion source and primary column are installed on a new Time-of-Flight secondary ion mass spectrometer for analysis of geological samples. The diameter of the ion beam was measured by the knife-edge method and a scanning electron microscope (SEM). Results show that an O2- beam of ca. 5 μm diameter with a beam intensity of ∼5 nA and an O- beam of ca. 5 μm diameter with a beam intensity of ∼50 nA were obtained, respectively. This design will open new possibilities for in-situ elemental and isotopic analysis in geological studies.

Study of Three-Dimensional Image Brightness Loss in Stereoscopy

Directory of Open Access Journals (Sweden)

Hsing-Cheng Yu

2015-10-01

Full Text Available When viewing three-dimensional (3D images, whether in cinemas or on stereoscopic televisions, viewers experience the same problem of image brightness loss. This study aims to investigate image brightness loss in 3D displays, with the primary aim being to quantify the image brightness degradation in the 3D mode. A further aim is to determine the image brightness relationship to the corresponding two-dimensional (2D images in order to adjust the 3D-image brightness values. In addition, the photographic principle is used in this study to measure metering values by capturing 2D and 3D images on television screens. By analyzing these images with statistical product and service solutions (SPSS software, the image brightness values can be estimated using the statistical regression model, which can also indicate the impact of various environmental factors or hardware on the image brightness. In analysis of the experimental results, comparison of the image brightness between 2D and 3D images indicates 60.8% degradation in the 3D image brightness amplitude. The experimental values, from 52.4% to 69.2%, are within the 95% confidence interval

CHANDRA ACIS SURVEY OF X-RAY POINT SOURCES: THE SOURCE CATALOG

Energy Technology Data Exchange (ETDEWEB)

Wang, Song; Liu, Jifeng; Qiu, Yanli; Bai, Yu; Yang, Huiqin; Guo, Jincheng; Zhang, Peng, E-mail: jfliu@bao.ac.cn, E-mail: songw@bao.ac.cn [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

2016-06-01

The Chandra archival data is a valuable resource for various studies on different X-ray astronomy topics. In this paper, we utilize this wealth of information and present a uniformly processed data set, which can be used to address a wide range of scientific questions. The data analysis procedures are applied to 10,029 Advanced CCD Imaging Spectrometer observations, which produces 363,530 source detections belonging to 217,828 distinct X-ray sources. This number is twice the size of the Chandra Source Catalog (Version 1.1). The catalogs in this paper provide abundant estimates of the detected X-ray source properties, including source positions, counts, colors, fluxes, luminosities, variability statistics, etc. Cross-correlation of these objects with galaxies shows that 17,828 sources are located within the D {sub 25} isophotes of 1110 galaxies, and 7504 sources are located between the D {sub 25} and 2 D {sub 25} isophotes of 910 galaxies. Contamination analysis with the log N –log S relation indicates that 51.3% of objects within 2 D {sub 25} isophotes are truly relevant to galaxies, and the “net” source fraction increases to 58.9%, 67.3%, and 69.1% for sources with luminosities above 10{sup 37}, 10{sup 38}, and 10{sup 39} erg s{sup −1}, respectively. Among the possible scientific uses of this catalog, we discuss the possibility of studying intra-observation variability, inter-observation variability, and supersoft sources (SSSs). About 17,092 detected sources above 10 counts are classified as variable in individual observation with the Kolmogorov–Smirnov (K–S) criterion ( P {sub K–S} < 0.01). There are 99,647 sources observed more than once and 11,843 sources observed 10 times or more, offering us a wealth of data with which to explore the long-term variability. There are 1638 individual objects (∼2350 detections) classified as SSSs. As a quite interesting subclass, detailed studies on X-ray spectra and optical spectroscopic follow-up are needed to

HIGH-RESOLUTION IMAGING OF THE ATLBS REGIONS: THE RADIO SOURCE COUNTS

Energy Technology Data Exchange (ETDEWEB)

Thorat, K.; Subrahmanyan, R.; Saripalli, L.; Ekers, R. D., E-mail: kshitij@rri.res.in [Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India)

2013-01-01

The Australia Telescope Low-brightness Survey (ATLBS) regions have been mosaic imaged at a radio frequency of 1.4 GHz with 6'' angular resolution and 72 {mu}Jy beam{sup -1} rms noise. The images (centered at R.A. 00{sup h}35{sup m}00{sup s}, decl. -67 Degree-Sign 00'00'' and R.A. 00{sup h}59{sup m}17{sup s}, decl. -67 Degree-Sign 00'00'', J2000 epoch) cover 8.42 deg{sup 2} sky area and have no artifacts or imaging errors above the image thermal noise. Multi-resolution radio and optical r-band images (made using the 4 m CTIO Blanco telescope) were used to recognize multi-component sources and prepare a source list; the detection threshold was 0.38 mJy in a low-resolution radio image made with beam FWHM of 50''. Radio source counts in the flux density range 0.4-8.7 mJy are estimated, with corrections applied for noise bias, effective area correction, and resolution bias. The resolution bias is mitigated using low-resolution radio images, while effects of source confusion are removed by using high-resolution images for identifying blended sources. Below 1 mJy the ATLBS counts are systematically lower than the previous estimates. Showing no evidence for an upturn down to 0.4 mJy, they do not require any changes in the radio source population down to the limit of the survey. The work suggests that automated image analysis for counts may be dependent on the ability of the imaging to reproduce connecting emission with low surface brightness and on the ability of the algorithm to recognize sources, which may require that source finding algorithms effectively work with multi-resolution and multi-wavelength data. The work underscores the importance of using source lists-as opposed to component lists-and correcting for the noise bias in order to precisely estimate counts close to the image noise and determine the upturn at sub-mJy flux density.

The lowest surface brightness disc galaxy known

International Nuclear Information System (INIS)

Davies, J.I.; Phillipps, S.; Disney, M.J.

1988-01-01

The discovery of a galaxy with a prominent bulge and a dominant extremely low surface brightness disc component is reported. The profile of this galaxy is very similar to the recently discovered giant low surface brightness galaxy Malin 1. The disc central surface brightness is found to be ∼ 26.4 Rμ, some 1.5 mag fainter than Malin 1 and thus by far the lowest yet observed. (author)

Discovery of source fault in the region without obvious active fault. Geophysical survey in the source area of the 1984 western Nagano prefecture earthquake

International Nuclear Information System (INIS)

Aoyagi, Yasuhira; Abe, Shintaro

2009-01-01

The 1984 Western Nagano Prefecture Earthquake (MJ6.8) occurred at shallow part of the southern foot of Mt. Ontake volcano, central Japan. Despite the large magnitude neither clear surface rupture nor active fault has been found around the source area. Therefore the earthquake is an issue for seismic assessment based on active fault survey. The purpose of this study is to find any tectonic geomorphologic features in the source area and to elucidate its relation to the source fault. In order to achieve it, an integrated survey with (1) micro earthquake observation, (2) airborne LIDAR, and (3) seismic reflection survey was demonstrated in the source area from 2006 to 2008. The survey area of airborne LIDAR (18 km x 4 km) covers main part of the aftershock distribution just after the mainshock. A linear zone with abrupt change of topographic roughness was found in ENE-WSW direction at the center of the LIDAR target area. River valleys flowing down to SSE direction change their directions and widths abruptly across the linear zone. Seismic reflection survey across the source region detect deformation zone just beneath the linear zone. These features of topographic and crustal deformation coincide well with the aftershock distribution. Therefore they indicate an active structure formed by the cumulative displacement of the source fault. (author)

Brightness masking is modulated by disparity structure.

Science.gov (United States)

Pelekanos, Vassilis; Ban, Hiroshi; Welchman, Andrew E

2015-05-01

The luminance contrast at the borders of a surface strongly influences surface's apparent brightness, as demonstrated by a number of classic visual illusions. Such phenomena are compatible with a propagation mechanism believed to spread contrast information from borders to the interior. This process is disrupted by masking, where the perceived brightness of a target is reduced by the brief presentation of a mask (Paradiso & Nakayama, 1991), but the exact visual stage that this happens remains unclear. In the present study, we examined whether brightness masking occurs at a monocular-, or a binocular-level of the visual hierarchy. We used backward masking, whereby a briefly presented target stimulus is disrupted by a mask coming soon afterwards, to show that brightness masking is affected by binocular stages of the visual processing. We manipulated the 3-D configurations (slant direction) of the target and mask and measured the differential disruption that masking causes on brightness estimation. We found that the masking effect was weaker when stimuli had a different slant. We suggest that brightness masking is partly mediated by mid-level neuronal mechanisms, at a stage where binocular disparity edge structure has been extracted. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Brightness and darkness as perceptual dimensions

NARCIS (Netherlands)

Vladusich, T.; Lucassen, M.P.; Cornelissen, F.W.

2007-01-01

A common-sense assumption concerning visual perception states that brightness and darkness cannot coexist at a given spatial location. One corollary of this assumption is that achromatic colors, or perceived grey shades, are contained in a one-dimensional (1-D) space varying from bright to dark. The

Effect of evening exposure to bright or dim light after daytime bright light on absorption of dietary carbohydrates the following morning.

Science.gov (United States)

Hirota, Naoko; Sone, Yoshiaki; Tokura, Hiromi

2010-01-01

We had previously reported on the effect of exposure to light on the human digestive system: daytime bright light exposure has a positive effect, whereas, evening bright light exposure has a negative effect on the efficiency of dietary carbohydrate absorption from the evening meal. These results prompted us to examine whether the light intensity to which subjects are exposed in the evening affects the efficiency of dietary carbohydrate absorption the following morning. In this study, subjects were exposed to either 50 lux (dim light conditions) or 2,000 lux (bright light conditions) in the evening for 9 h (from 15:00 to 24:00) after staying under bright light in the daytime (under 2,000 lux from 07:00 to 15:00). We measured unabsorbed dietary carbohydrates using the breath-hydrogen test the morning after exposure to either bright light or dim light the previous evening. Results showed that there was no significant difference between the two conditions in the amount of breath hydrogen. This indicates that evening exposure to bright or dim light after bright light exposure in the daytime has no varying effect on digestion or absorption of dietary carbohydrates in the following morning's breakfast.

Inversion methods for analysis of neutron brightness measurements in tokamaks

International Nuclear Information System (INIS)

Gorini, G.; Gottardi, N.

1990-02-01

The problem of determining neutron emissivity from neutron brightness measurements in magnetic fusion plasmas is addressed. In the case of two-dimensional measurements with two orthogonal cameras, a complete, tomographic analysis of the data can in principle be performed. The results depend critically on the accuracy of the measurements and alternative solutions can be sought under the assumption of a known emissivity topology (Generalized Abel Inversion). In this work, neutron brightness data from the JET tokamak have been studied with both methods. We find that with the present experimental uncertainty (levels 10-20%) the Abel inversion method works best, while two-dimensional information cannot in general be deduced. This is confirmed by studies of the error propagation in the inversion using artificial data, which are also presented here. An important application of emissivity profile information is the determination of the plasma deuterium temperature profile, T D (R). Results are presented here from the analysis of JET data and the errors in T D (R) are discussed in some detail. It is found that, for typical JET plasma conditions, the dominant source of uncertainty arises from the high plasma impurity level and the fact that it is poorly known; these problems can be expected to be remedied and neutron brightness measurements would be expected to be very effective (especially in high density plasmas) as a T D (R) diagnostics. (author)

VizieR Online Data Catalog: XXL Survey: First results (Pierre+, 2016)

Science.gov (United States)

Pierre, M.; Pacaud, F.; Adami, C.; Alis, S.; Altieri, B.; Baran, B.; Benoist, C.; Birkinshaw, M.; Bongiorno, A.; Bremer, M. N.; Brusa, M.; Butler, A.; Ciliegi, P.; Chiappetti, L.; Clerc, N.; Corasaniti, P. S.; Coupon, J.; De Breuck, C.; Democles, J.; Desai, S.; Delhaize, J.; Devriendt, J.; Dubois, Y.; Eckert, D.; Elyiv, A.; Ettori, S.; Evrard, A.; Faccioli, L.; Farahi, A.; Ferrari, C.; Finet, F.; Fotopoulou, S.; Fourmanoit, N.; Gandhi, P.; Gastaldello, F.; Gastaud, R.; Georgantopoulos, I.; Giles, P.; Guennou, L.; Guglielmo, V.; Horellou, C.; Husband, K.; Huynh, M.; Iovino, A.; Kilbinger, M.; Koulouridis, E.; Lavoie, S.; Le Brun, A. M. C.; Lefevre, J. P.; Lidman, C.; Lieu, M.; Lin, C. A.; Mantz, A.; Maughan, B. J.; Maurogordato, S.; McCarthy, I. G.; McGee, S.; Melin, J. B.; Melnyk, O.; Menanteau, F.; Novak, M.; Paltani, S.; Plionis, M.; Poggianti, B. M.; Pomarede, D.; Pompei, E.; Ponman, T. J.; Ramos-Ceja, M. E.; Ranalli, P.; Rapetti, D.; Raychaudury, S.; Reiprich, T. H.; Rottgering, H.; Rozo, E.; Ryko, E.; Sadibekova, T.; Santos, J.; Sauvageot, J. L.; Schimd, C.; Sereno, M.; Smith, G. P.; Smolcic, V.; Snowden, S.; Spergel, D.; Stanford, S.; Surdej, J.; Valageas, P.; Valotti, A.; Valtchanov, I.; Vignali, C.; Willis, J.; Ziparo, F.

2016-03-01

Paper I. Scientific motivations - XMM-Newton observing plan. Follow-up observations and simulation programme. The table xxlpoint.dat is a list of all XMM survey-type observations (quality and ancillary information. Paper II. The bright cluster sample: catalogue and luminosity function. Paper III. Luminosity-temperature relation of the bright cluster sample. Paper IV. Mass-temperature relation of the bright cluster sample. This article presents the XXL bright cluster sample, a subsample of 100 galaxy clusters selected from the full XXL catalogue by setting a lower limit of 3*10-14erg/cm2/s on the source flux within a 1' aperture. The selection function was estimated using a mixture of Monte Carlo simulations and analytical recipes that closely reproduce the source selection process. An extensive spectroscopic follow-up provided redshifts for 97 of the 100 clusters. We derived accurate X-ray parameters for all the sources. Scaling relations were self-consistently derived from the same sample in other publications of the series. On this basis, we study the number density, luminosity function, and spatial distribution of the sample. The bright cluster sample consists of systems with masses between M500=7*10+14 and 3*10+14Mȯ, mostly located between z=0.1 and 0.5. The observed sky density of clusters is slightly below the predictions from the WMAP9 model, and significantly below the prediction from the Planck 2015 cosmology. In general, within the current uncertainties of the cluster mass calibration, models with higher values of σ8 and/or ΩM appear more difficult to accommodate. We provide tight constraints on the cluster differential luminosity function and find no hint of evolution out to z~1. We also find strong evidence for the presence of large-scale structures in the XXL bright cluster sample and identify five new superclusters. We provide the XXL-100-GC catalogue (xxl100gc.dat), the master catalogue of the 100 brightest galaxy clusters from the XXL Survey

A Survey of Open Source Tools for Business Intelligence

DEFF Research Database (Denmark)

Thomsen, Christian; Pedersen, Torben Bach

The industrial use of open source Business Intelligence (BI) tools is becoming more common, but is still not as widespread as for other types of software.  It is therefore of interest to explore which possibilities are available for open source BI and compare the tools. In this survey paper, we c......The industrial use of open source Business Intelligence (BI) tools is becoming more common, but is still not as widespread as for other types of software.  It is therefore of interest to explore which possibilities...... are available for open source BI and compare the tools. In this survey paper, we consider the capabilities of a number of open source tools for BI. In the paper, we consider a number of Extract‐Transform‐Load (ETL) tools, database management systems (DBMSs), On‐Line Analytical Processing (OLAP) servers, and OLAP clients. We find that, unlike the situation a few years ago, there now...

A 31 GHz Survey of Low-Frequency Selected Radio Sources

Science.gov (United States)

Mason, B. S.; Weintraub, L.; Sievers, J.; Bond, J. R.; Myers, S. T.; Pearson, T. J.; Readhead, A. C. S.; Shepherd, M. C.

2009-10-01

The 100 m Robert C. Byrd Green Bank Telescope and the 40 m Owens Valley Radio Observatory telescope have been used to conduct a 31 GHz survey of 3165 known extragalactic radio sources over 143 deg2 of the sky. Target sources were selected from the NRAO VLA Sky Survey in fields observed by the Cosmic Background Imager (CBI); most are extragalactic active galactic nuclei (AGNs) with 1.4 GHz flux densities of 3-10 mJy. The resulting 31 GHz catalogs are presented in full online. Using a maximum-likelihood analysis to obtain an unbiased estimate of the distribution of the 1.4-31 GHz spectral indices of these sources, we find a mean 31-1.4 GHz flux ratio of 0.110 ± 0.003 corresponding to a spectral index of α = -0.71 ± 0.01 (S ν vprop να) 9.0% ± 0.8% of sources have α > - 0.5 and 1.2% ± 0.2% have α > 0. By combining this spectral-index distribution with 1.4 GHz source counts, we predict 31 GHz source counts in the range 1 mJy S 31) = (16.7 ± 1.7) deg-2(S 31/1 mJy)-0.80±0.07. We also assess the contribution of mJy-level (S 1.4 GHz < 3.4 mJy) radio sources to the 31 GHz cosmic microwave background power spectrum, finding a mean power of ell(ell + 1)C src ell/(2π) = 44 ± 14 μK2 and a 95% upper limit of 80 μK2 at ell = 2500. Including an estimated contribution of 12 μK2 from the population of sources responsible for the turn-up in counts below S 1.4 GHz = 1 mJy, this amounts to 21% ± 7% of what is needed to explain the CBI high-ell excess signal, 275 ± 63 μK2. These results are consistent with other measurements of the 31 GHz point-source foreground.

Multiwavelength Study of Gamma-Ray Bright Blazars

Science.gov (United States)

Morozova, Daria; Larionov, V. M.; Hagen-Thorn, V. A.; Jorstad, S. G.; Marscher, A. P.; Troitskii, I. S.

2011-01-01

We investigate total intensity radio images of 6 gamma-ray bright blazars (BL Lac, 3C 279, 3C 273, W Com, PKS 1510-089, and 3C 66A) and their optical and gamma-ray light curves to study connections between gamma-ray and optical brightness variations and changes in the parsec-scale radio structure. We use high-resolution maps obtained by the BU group at 43 GHz with the VLBA, optical light curves constructed by the St.Petersburg State U. (Russia) team using measurements with the 0.4 m telescope of St.Petersburg State U. (LX200) and the 0.7 m telescope of the Crimean Astrophysical Observatory (AZT-8), and gamma-ray light curves, which we have constructed with data provided by the Fermi Large Area Telescope. Over the period from August 2008 to November 2009, superluminal motion is found in all 6 objects with apparent speed ranging from 2c to 40c. The blazars with faster apparent speeds, 3C 273, 3C 279, PKS 1510-089, and 3C 66A, exhibit stronger variability of the gamma-ray emission. There is a tendency for sources with sharply peaked gamma-ray flares to have faster jet speed than sources with gamma-ray light curves with no sharp peaks. Gamma-ray light curves with sharply peaked gamma-ray flares possess a stronger gamma-ray/optical correlations. The research at St.Petersburg State U. was funded by the Minister of Education and Science of the Russian Federation (state contract N#P123). The research at BU was funded in part by NASA Fermi Guest Investigator grant NNX08AV65G and by NSF grant AST-0907893. The VLBA is an instrument of the National Radio Astronomy Observatory, a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

No time for dead time: timing analysis of bright black hole binaries with NuSTAR

DEFF Research Database (Denmark)

Bachetti, Matteo; Harrison, Fiona A.; Cook, Rick

2015-01-01

Timing of high-count-rate sources with the NuSTAR Small Explorer Mission requires specialized analysis techniques. NuSTAR was primarily designed for spectroscopic observations of sources with relatively low count rates rather than for timing analysis of bright objects. The instrumental dead time ...... techniques. We apply this technique to NuSTAR observations of the black hole binaries GX 339-4, Cyg X-1, and GRS 1915+105....

Investigation of fundamental limits to beam brightness available from photoinjectors

International Nuclear Information System (INIS)

Bazarov, Ivan

2015-01-01

The goal of this project was investigation of fundamental limits to beam brightness available from photoinjectors. This basic research in accelerator physics spanned over 5 years aiming to extend the fundamental understanding of high average current, low emittance sources of relativistic electrons based on photoemission guns, a necessary prerequisite for a new generation of coherent X-ray synchrotron radiation facilities based on continuous duty superconducting linacs. The program focused on two areas critical to making advances in the electron source performance: 1) the physics of photocathodes for the production of low emittance electrons and 2) control of space charge forces in the immediate vicinity to the cathode via 3D laser pulse shaping.

Investigation of fundamental limits to beam brightness available from photoinjectors

Energy Technology Data Exchange (ETDEWEB)

Bazarov, Ivan [Cornell Univ., Ithaca, NY (United States)

2015-07-09

The goal of this project was investigation of fundamental limits to beam brightness available from photoinjectors. This basic research in accelerator physics spanned over 5 years aiming to extend the fundamental understanding of high average current, low emittance sources of relativistic electrons based on photoemission guns, a necessary prerequisite for a new generation of coherent X-ray synchrotron radiation facilities based on continuous duty superconducting linacs. The program focused on two areas critical to making advances in the electron source performance: 1) the physics of photocathodes for the production of low emittance electrons and 2) control of space charge forces in the immediate vicinity to the cathode via 3D laser pulse shaping.

Final Report on DTRA Basic Research Project #BRCALL08-Per3-C-2-0006 "High-Z Non-Equilibrium Physics and Bright X-ray Sources with New Laser Targets"

Energy Technology Data Exchange (ETDEWEB)

Colvin, Jeffrey D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-06-01

This project had two major goals. Final Goal: obtain spectrally resolved, absolutely calibrated x-ray emission data from uniquely uniform mm-scale near-critical-density high-Z plasmas not in local thermodynamic equilibrium (LTE) to benchmark modern detailed atomic physics models. Scientific significance: advance understanding of non-LTE atomic physics. Intermediate Goal: develop new nano-fabrication techniques to make suitable laser targets that form the required highly uniform non-LTE plasmas when illuminated by high-intensity laser light. Scientific significance: advance understanding of nano-science. The new knowledge will allow us to make x-ray sources that are bright at the photon energies of most interest for testing radiation hardening technologies, the spectral energy range where current x-ray sources are weak. All project goals were met.

The night sky brightness at McDonald Observatory

Science.gov (United States)

Kalinowski, J. K.; Roosen, R. G.; Brandt, J. C.

1975-01-01

Baseline observations of the night sky brightness in B and V are presented for McDonald Observatory. In agreement with earlier work by Elvey and Rudnick (1937) and Elvey (1943), significant night-to-night and same-night variations in sky brightness are found. Possible causes for these variations are discussed. The largest variation in sky brightness found during a single night is approximately a factor of two, a value which corresponds to a factor-of-four variation in airglow brightness. The data are used to comment on the accuracy of previously published surface photometry of M 81.

Source finding in linear polarization for LOFAR, and SKA predecessor surveys, using Faraday moments

Science.gov (United States)

Farnes, J. S.; Heald, G.; Junklewitz, H.; Mulcahy, D. D.; Haverkorn, M.; Van Eck, C. L.; Riseley, C. J.; Brentjens, M.; Horellou, C.; Vacca, V.; Jones, D. I.; Horneffer, A.; Paladino, R.

2018-03-01

The optimal source-finding strategy for linear polarization data is an unsolved problem, with many inhibitive factors imposed by the technically challenging nature of polarization observations. Such an algorithm is essential for Square Kilometre Array (SKA) pathfinder surveys, such as the Multifrequency Snapshot Sky Survey with the LOw Frequency ARray (LOFAR), as data volumes are significant enough to prohibit manual inspection. We present a new strategy of `Faraday Moments' for source-finding in linear polarization with LOFAR, using the moments of the frequency-dependent full-Stokes data (i.e. the mean, standard deviation, skewness, and excess kurtosis). Through simulations of the sky, we find that moments can identify polarized sources with a high completeness: 98.5 per cent at a signal to noise of 5. While the method has low reliability, rotation measure (RM) synthesis can be applied per candidate source to filter out instrumental and spurious detections. This combined strategy will result in a complete and reliable catalogue of polarized sources that includes the full sensitivity of the observational bandwidth. We find that the technique can reduce the number of pixels on which RM Synthesis needs to be performed by a factor of ≈1 × 105 for source distributions anticipated with modern radio telescopes. Through tests on LOFAR data, we find that the technique works effectively in the presence of diffuse emission. Extensions of this method are directly applicable to other upcoming radio surveys such as the POlarization Sky Survey of the Universe's Magnetism with the Australia Square Kilometre Array Pathfinder, and the SKA itself.

Selection effects in the bivariate brightness distribution for spiral galaxies

International Nuclear Information System (INIS)

Phillipps, S.; Disney, M.

1986-01-01

The joint distribution of total luminosity and characteristic surface brightness (the bivariate brightness distribution) is investigated for a complete sample of spiral galaxies in the Virgo cluster. The influence of selection and physical limits of various kinds on the apparent distribution are detailed. While the distribution of surface brightness for bright galaxies may be genuinely fairly narrow, faint galaxies exist right across the (quite small) range of accessible surface brightnesses so no statement can be made about the true extent of the distribution. The lack of high surface brightness bright galaxies in the Virgo sample relative to an overall RC2 sample (mostly field galaxies) supports the contention that the star-formation rate is reduced in the inner region of the cluster for environmental reasons. (author)

Contingent valuation method applied to survey on personal preferences on choice of electric power source

International Nuclear Information System (INIS)

Takahashi, Reiko; Nakagome, Yoshihiro

2004-01-01

A Survey was conducted on personal preferences regarding their choice of electric power source to verify the applicability of Contingent Valuation Method (CVM) to such analysis. The survey was carried out on local and urban inhabitants in two steps, first by mail and thereafter by direct interview. A choice of four typical forms of power source was presented: nuclear, coal, hydro and green power; and the question was asked whether the respondent would be willing to pay additional charge for specifying their preferable power source. The mail survey indicated more than half of the respondents hold some willingness to pay either for disuse of nuclear power or expansion of green power. The interview survey revealed various complex motives lying behind their answers. Consequently, it was found that their preference is significantly correlated to their personal image or knowledge of power sources, their thinking or attitude toward energy conservation, their sense of consumption and their private view of life. It is concluded that CVM is pertinently applicable to quantitative analysis of individual opinions, particularly in terms of their motivation to participate in national energy issues. A number of modifications, however, should be required to be brought to the survey design in order to ensure smooth application in practice. (author)

THE PANCHROMATIC HUBBLE ANDROMEDA TREASURY. I. BRIGHT UV STARS IN THE BULGE OF M31

International Nuclear Information System (INIS)

Rosenfield, Philip; Johnson, L. Clifton; Dalcanton, Julianne J.; Williams, Benjamin F.; Gilbert, Karoline M.; Girardi, Léo; Bressan, Alessandro; Lang, Dustin; Guhathakurta, Puragra; Dorman, Claire E.; Howley, Kirsten M.; Lauer, Tod R.; Olsen, Knut A. G.; Bell, Eric F.; Bianchi, Luciana; Caldwell, Nelson; Dolphin, Andrew; Kalirai, Jason; Larsen, Søren S.; Rix, Hans-Walter

2012-01-01

As part of the Panchromatic Hubble Andromeda Treasury multi-cycle program, we observed a 12' × 6.'5 area of the bulge of M31 with the WFC3/UVIS filters F275W and F336W. From these data we have assembled a sample of ∼4000 UV-bright, old stars, vastly larger than previously available. We use updated Padova stellar evolutionary tracks to classify these hot stars into three classes: Post-AGB stars (P-AGB), Post-Early AGB (PE-AGB) stars, and AGB-manqué stars. P-AGB stars are the end result of the asymptotic giant branch (AGB) phase and are expected in a wide range of stellar populations, whereas PE-AGB and AGB-manqué (together referred to as the hot post-horizontal branch; HP-HB) stars are the result of insufficient envelope masses to allow a full AGB phase, and are expected to be particularly prominent at high helium or α abundances when the mass loss on the red giant branch is high. Our data support previous claims that most UV-bright sources in the bulge are likely hot (extreme) horizontal branch (EHB) stars and their progeny. We construct the first radial profiles of these stellar populations and show that they are highly centrally concentrated, even more so than the integrated UV or optical light. However, we find that this UV-bright population does not dominate the total UV luminosity at any radius, as we are detecting only the progeny of the EHB stars that are the likely source of the UV excess. We calculate that only a few percent of main-sequence stars in the central bulge can have gone through the HP-HB phase and that this percentage decreases strongly with distance from the center. We also find that the surface density of hot UV-bright stars has the same radial variation as that of low-mass X-ray binaries. We discuss age, metallicity, and abundance variations as possible explanations for the observed radial variation in the UV-bright population.

Dark-Bright Soliton Dynamics Beyond the Mean-Field Approximation

Science.gov (United States)

Katsimiga, Garyfallia; Koutentakis, Georgios; Mistakidis, Simeon; Kevrekidis, Panagiotis; Schmelcher, Peter; Theory Group of Fundamental Processes in Quantum Physics Team

2017-04-01

The dynamics of dark bright solitons beyond the mean-field approximation is investigated. We first examine the case of a single dark-bright soliton and its oscillations within a parabolic trap. Subsequently, we move to the setting of collisions, comparing the mean-field approximation to that involving multiple orbitals in both the dark and the bright component. Fragmentation is present and significantly affects the dynamics, especially in the case of slower solitons and in that of lower atom numbers. It is shown that the presence of fragmentation allows for bipartite entanglement between the distinguishable species. Most importantly the interplay between fragmentation and entanglement leads to the decay of each of the initial mean-field dark-bright solitons into fast and slow fragmented dark-bright structures. A variety of excitations including dark-bright solitons in multiple (concurrently populated) orbitals is observed. Dark-antidark states and domain-wall-bright soliton complexes can also be observed to arise spontaneously in the beyond mean-field dynamics. Deutsche Forschungsgemeinschaft (DFG) in the framework of the SFB 925 ``Light induced dynamics and control of correlated quantum systems''.

Diagnostics for high-brightness beams

International Nuclear Information System (INIS)

Shafer, R.E.

1990-01-01

Special techniques are required for beam diagnostics on high-brightness particle beams. Examples of high-brightness beams include low-emittance proton linacs (either pulsed or CW), electron linacs suitable for free-electron-laser applications, and future linear colliders. Non-interceptive and minimally-interceptive techniques for measuring beam current, position, profile, and transverse and longitudinal emittance will be reviewed. Included will be stripline, wire scanner, laser neutralization, beam-beam scattering, interceptive microgratings, spontaneous emission, optical transition radiation, and other techniques. 24 refs

Characterization of Various Survey Meters by Car-borne Survey in Java Island as Basis Data for Searching Orphan Sources

International Nuclear Information System (INIS)

Yus Rusdian Akhmad

2004-01-01

Recently, an international collaboration in securing and managing radioactive sources, particularly orphan sources, is established. For developing countries such as Indonesia which possesses relatively inadequate resources, an effective approach in dealing with the problem is crucial. In order to deal with this situation, an activity was performed including: 1) assessment of available technical means, 2) car-borne survey during the dry and rainy seasons to identify the impact of Rn daughter washout on the interpretation of search results, 3) search for anomalies in the radioactive exposure map of the Java island, and 4) investigation of anomalies found, using more sophisticated instrument, to detect and secure orphan and illicit radioactive sources. The performance of four selected instruments in a car-borne survey which covers a large area in western part of Java was evaluated. Data series of moving background were divided into two measurement groups; control group and test group. These data series were arranged in, order to determine the value of alarm level. For this purpose, statistic procedures relying on Mann-Whitney U test and a simple moving average test (Moving Background) were applied. Among the four selected survey meters, the most convenient detection system for implementing the activity is Exploranium GR-130. There was little concern on the effect of Rn-daughters washouts on the proposed methods, provided that the operator could recognise the transition period between the clear and rainy weather as it could give rise to false alarm. The Moving Background method was generally superior to Mann-Whitney U test for detecting anomalous radiation level. During the survey, an anomaly in steel industrial area was detected. Using portable gamma spectrometers, it was concluded that the anomaly was generated from naturally occurring radioactive materials (NORM). Analyses upon survey data in the big cities showed anomalies due to concrete structures, especially

A Survey of Open-Source UAV Flight Controllers and Flight Simulators

DEFF Research Database (Denmark)

Ebeid, Emad Samuel Malki; Skriver, Martin; Terkildsen, Kristian Husum

2018-01-01

The current disruptive innovation in civilian drone (UAV) applications has led to an increased need for research and development in UAV technology. The key challenges currently being addressed are related to UAV platform properties such as functionality, reliability, fault tolerance, and endurance......-source drone platform elements that can be used for research and development. The survey covers open-source hardware, software, and simulation drone platforms and compares their main features....

High brightness semiconductor lasers with reduced filamentation

DEFF Research Database (Denmark)

McInerney, John; O'Brien, Peter.; Skovgaard, Peter M. W.

1999-01-01

High brightness semiconductor lasers have applications in spectroscopy, fiber lasers, manufacturing and materials processing, medicine and free space communication or energy transfer. The main difficulty associated with high brightness is that, because of COD, high power requires a large aperture...

The optical, infrared and radio properties of extragalactic sources observed by SDSS, 2mass and first surveys

International Nuclear Information System (INIS)

Z. Ivezic et al.

2002-01-01

We positionally match sources observed by the Sloan Digital Sky Survey (SDSS), the Two Micron All Sky Survey (2MASS), and the Faint Images of the Radio Sky at Twenty-cm (FIRST) survey. Practically all 2MASS sources are matched to an SDSS source within 2 arcsec; ∼ 11% of them are optically resolved galaxies and the rest are dominated by stars. About 1/3 of FIRST sources are matched to an SDSS source within 2 arcsec; ∼ 80% of these are galaxies and the rest are dominated by quasars. Based on these results, we project that by the completion of these surveys the matched samples will include about 10 7 and 10 6 galaxies observed by both SDSS and 2MASS, and about 250,000 galaxies and 50,000 quasars observed by both SDSS and FIRST. Here we present a preliminary analysis of the optical, infrared and radio properties for the extragalactic sources from the matched samples. In particular, we find that the fraction of quasars with stellar colors missed by the SDSS spectroscopic survey is probably not larger than ∼ 10%, and that the optical colors of radio-loud quasars are ∼ 0.05 mag. redder (with 4σ significance) than the colors of radio-quiet quasars

The XMM-SERVS survey: new XMM-Newton point-source catalog for the XMM-LSS field

Science.gov (United States)

Chen, C.-T. J.; Brandt, W. N.; Luo, B.; Ranalli, P.; Yang, G.; Alexander, D. M.; Bauer, F. E.; Kelson, D. D.; Lacy, M.; Nyland, K.; Tozzi, P.; Vito, F.; Cirasuolo, M.; Gilli, R.; Jarvis, M. J.; Lehmer, B. D.; Paolillo, M.; Schneider, D. P.; Shemmer, O.; Smail, I.; Sun, M.; Tanaka, M.; Vaccari, M.; Vignali, C.; Xue, Y. Q.; Banerji, M.; Chow, K. E.; Häußler, B.; Norris, R. P.; Silverman, J. D.; Trump, J. R.

2018-04-01

We present an X-ray point-source catalog from the XMM-Large Scale Structure survey region (XMM-LSS), one of the XMM-Spitzer Extragalactic Representative Volume Survey (XMM-SERVS) fields. We target the XMM-LSS region with 1.3 Ms of new XMM-Newton AO-15 observations, transforming the archival X-ray coverage in this region into a 5.3 deg2 contiguous field with uniform X-ray coverage totaling 2.7 Ms of flare-filtered exposure, with a 46 ks median PN exposure time. We provide an X-ray catalog of 5242 sources detected in the soft (0.5-2 keV), hard (2-10 keV), and/or full (0.5-10 keV) bands with a 1% expected spurious fraction determined from simulations. A total of 2381 new X-ray sources are detected compared to previous source catalogs in the same area. Our survey has flux limits of 1.7 × 10-15, 1.3 × 10-14, and 6.5 × 10-15 erg cm-2 s-1 over 90% of its area in the soft, hard, and full bands, respectively, which is comparable to those of the XMM-COSMOS survey. We identify multiwavelength counterpart candidates for 99.9% of the X-ray sources, of which 93% are considered as reliable based on their matching likelihood ratios. The reliabilities of these high-likelihood-ratio counterparts are further confirmed to be ≈97% reliable based on deep Chandra coverage over ≈5% of the XMM-LSS region. Results of multiwavelength identifications are also included in the source catalog, along with basic optical-to-infrared photometry and spectroscopic redshifts from publicly available surveys. We compute photometric redshifts for X-ray sources in 4.5 deg2 of our field where forced-aperture multi-band photometry is available; >70% of the X-ray sources in this subfield have either spectroscopic or high-quality photometric redshifts.

Burkina Faso - BRIGHT II

Data.gov (United States)

Millennium Challenge Corporation — Millennium Challenge Corporation hired Mathematica Policy Research to conduct an independent evaluation of the BRIGHT II program. The three main research questions...

HERschel key program heritage: A far-infrared source catalog for the Magellanic Clouds

International Nuclear Information System (INIS)

Seale, Jonathan P.; Meixner, Margaret; Sewiło, Marta; Babler, Brian; Engelbracht, Charles W.; Misselt, Karl; Montiel, Edward; Gordon, Karl; Roman-Duval, Julia; Hony, Sacha; Okumura, Koryo; Panuzzo, Pasquale; Sauvage, Marc; Boyer, Martha L.; Chen, C.-H. Rosie; Indebetouw, Remy; Matsuura, Mikako; Oliveira, Joana M.; Loon, Jacco Th. van; Srinivasan, Sundar

2014-01-01

Observations from the HERschel Inventory of the Agents of Galaxy Evolution (HERITAGE) have been used to identify dusty populations of sources in the Large and Small Magellanic Clouds (LMC and SMC). We conducted the study using the HERITAGE catalogs of point sources available from the Herschel Science Center from both the Photodetector Array Camera and Spectrometer (PACS; 100 and 160 μm) and Spectral and Photometric Imaging Receiver (SPIRE; 250, 350, and 500 μm) cameras. These catalogs are matched to each other to create a Herschel band-merged catalog and then further matched to archival Spitzer IRAC and MIPS catalogs from the Spitzer Surveying the Agents of Galaxy Evolution (SAGE) and SAGE-SMC surveys to create single mid- to far-infrared (far-IR) point source catalogs that span the wavelength range from 3.6 to 500 μm. There are 35,322 unique sources in the LMC and 7503 in the SMC. To be bright in the FIR, a source must be very dusty, and so the sources in the HERITAGE catalogs represent the dustiest populations of sources. The brightest HERITAGE sources are dominated by young stellar objects (YSOs), and the dimmest by background galaxies. We identify the sources most likely to be background galaxies by first considering their morphology (distant galaxies are point-like at the resolution of Herschel) and then comparing the flux distribution to that of the Herschel Astrophysical Terahertz Large Area Survey (ATLAS) survey of galaxies. We find a total of 9745 background galaxy candidates in the LMC HERITAGE images and 5111 in the SMC images, in agreement with the number predicted by extrapolating from the ATLAS flux distribution. The majority of the Magellanic Cloud-residing sources are either very young, embedded forming stars or dusty clumps of the interstellar medium. Using the presence of 24 μm emission as a tracer of star formation, we identify 3518 YSO candidates in the LMC and 663 in the SMC. There are far fewer far-IR bright YSOs in the SMC than the LMC

HERschel key program heritage: A far-infrared source catalog for the Magellanic Clouds

Energy Technology Data Exchange (ETDEWEB)

Seale, Jonathan P.; Meixner, Margaret; Sewiło, Marta [The Johns Hopkins University, Department of Physics and Astronomy, 366 Bloomberg Center, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Babler, Brian [Department of Astronomy, 475 North Charter St., University of Wisconsin, Madison, WI 53706 (United States); Engelbracht, Charles W.; Misselt, Karl; Montiel, Edward [Steward Observatory, University of Arizona, 933 North Cherry Ave., Tucson, AZ 85721 (United States); Gordon, Karl; Roman-Duval, Julia [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Hony, Sacha; Okumura, Koryo; Panuzzo, Pasquale; Sauvage, Marc [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Boyer, Martha L. [Observational Cosmology Laboratory, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Chen, C.-H. Rosie [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Indebetouw, Remy [National Radio Astronomy Observatory, 520 Edgemont Road Charlottesville, VA 22903 (United States); Matsuura, Mikako [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Oliveira, Joana M.; Loon, Jacco Th. van [School of Physical and Geographical Sciences, Lennard-Jones Laboratories, Keele University, Staffordshire ST5 5BG (United Kingdom); Srinivasan, Sundar [UPMC-CNRS UMR7095, Institute d' Astrophysique de Paris, F-75014 Paris (France); and others

2014-12-01

Observations from the HERschel Inventory of the Agents of Galaxy Evolution (HERITAGE) have been used to identify dusty populations of sources in the Large and Small Magellanic Clouds (LMC and SMC). We conducted the study using the HERITAGE catalogs of point sources available from the Herschel Science Center from both the Photodetector Array Camera and Spectrometer (PACS; 100 and 160 μm) and Spectral and Photometric Imaging Receiver (SPIRE; 250, 350, and 500 μm) cameras. These catalogs are matched to each other to create a Herschel band-merged catalog and then further matched to archival Spitzer IRAC and MIPS catalogs from the Spitzer Surveying the Agents of Galaxy Evolution (SAGE) and SAGE-SMC surveys to create single mid- to far-infrared (far-IR) point source catalogs that span the wavelength range from 3.6 to 500 μm. There are 35,322 unique sources in the LMC and 7503 in the SMC. To be bright in the FIR, a source must be very dusty, and so the sources in the HERITAGE catalogs represent the dustiest populations of sources. The brightest HERITAGE sources are dominated by young stellar objects (YSOs), and the dimmest by background galaxies. We identify the sources most likely to be background galaxies by first considering their morphology (distant galaxies are point-like at the resolution of Herschel) and then comparing the flux distribution to that of the Herschel Astrophysical Terahertz Large Area Survey (ATLAS) survey of galaxies. We find a total of 9745 background galaxy candidates in the LMC HERITAGE images and 5111 in the SMC images, in agreement with the number predicted by extrapolating from the ATLAS flux distribution. The majority of the Magellanic Cloud-residing sources are either very young, embedded forming stars or dusty clumps of the interstellar medium. Using the presence of 24 μm emission as a tracer of star formation, we identify 3518 YSO candidates in the LMC and 663 in the SMC. There are far fewer far-IR bright YSOs in the SMC than the LMC

A connection between the X-ray spectral branches and the radio brightness in GX17+2

International Nuclear Information System (INIS)

Penninx, Wim; Lewin, W.H.G.; Paradijs, J. van; Klis, M. van der

1988-01-01

GX17 + 2(4U 1813 - 14) is a bright X-ray binary in which matter is accreting on to a neutron star from a nearby companion. X-ray bursts are sometimes observed, as well as quasiperiodic oscillations in the X-ray flux. The frequencies of the quasiperiodic oscillations depend on the spectral state of the source, which manifests itself as three distinct spectral 'branches' in an X-ray colour-colour diagram. GX17 + 2 is also a variable radio source; there is no believable optical counterpart. We report here on simultaneous X-ray and radio observations which showed a connection between the spectral branches and the radio brightness. The 6-cm and 20-cm flux density increased by factors of 30±5 and 40± 10, respectively, as the X-ray state changed from the so-called 'flaring branch' to the 'horizontal branch'. (author)

The Andromeda Optical and Infrared Disk Survey

Science.gov (United States)

Sick, J.; Courteau, S.; Cuillandre, J.-C.

2014-03-01

The Andromeda Optical and Infrared Disk Survey has mapped M31 in u* g' r' i' JKs wavelengths out to R = 40 kpc using the MegaCam and WIRCam wide-field cameras on the Canada-France-Hawaii Telescope. Our survey is uniquely designed to simultaneously resolve stars while also carefully reproducing the surface brightness of M31, allowing us to study M31's global structure in the context of both resolved stellar populations and spectral energy distributions. We use the Elixir-LSB method to calibrate the optical u* g' r' i' images by building real-time maps of the sky background with sky-target nodding. These maps are stable to μg ≲ 28.5 mag arcsec-2 and reveal warps in the outer M31 disk in surface brightness. The equivalent WIRCam mapping in the near-infrared uses a combination of sky-target nodding and image-to-image sky offset optimization to produce stable surface brightnesses. This study enables a detailed analysis of the systematics of spectral energy distribution fitting with near-infrared bands where asymptotic giant branch stars impose a significant, but ill-constrained, contribution to the near-infrared light of a galaxy. Here we present panchromatic surface brightness maps and initial results from our near-infrared resolved stellar catalog.

On the errors in measurements of Ohio 5 radio sources in the light of the GB survey

International Nuclear Information System (INIS)

Machalski, J.

1975-01-01

Positions and flux densities of 405 OSU 5 radio sources surveyed at 1415 MHz down to 0.18 f.u. (Brundage et al. 1971) have been examined in the light of data from the GB survey made at 1400 MHz (Maslowski 1972). An identification analysis has shown that about 56% of OSU sources reveal themselves as single, 18% - as confused, 20% - as unresolved and 6% - having no counterparts in the GB survey down to 0.09 f.u. - seem to be spurious. The single OSU sources are strongly affected by the underestimation of their flux densities due to base-line procedure in their vicinity. The average value of about 0.03 f.u. has been found for the systematic underestimation. The second systematic error is due to the presence of a significant number of confused sources with strong overestimation of their flux densities. The confusion effect gives a characteristic non-Gaussian tail in the difference distribution between observed and real flux densities. The confusion effect has a strong influence on source counts from the OSU 5 survey. Differential number-counts relatively to that from the GB survey shows that the counts agree between themselves within the statistical uncertainty up to about 0.40 f.u., which is approximately 4 delta (delta - average rms flux density error in the OSU 5 survey). Below 0.40 f.u. the number of sources missing due to the confusion effect is significantly greater than the number-overestimation due to the noise error. Thus, this part of the OSU 5 source counts cannot be treated seriously, even in the statistical sense. An analysis of the approximate reliability and completeness of the OSU 5 survey shows that, although the total reliability estimated by the authors of the survey is good, the completeness is significantly lower due to the underestimation of the confusion effect magnitude. In fact, the OSU 5 completeness is 67% at 0.18 f.u. and 79% at 0.25 f.u. (author)

Evaluation of the brightness of lightning channels and branches using the magnitude system: Application of astronomical photometry

Directory of Open Access Journals (Sweden)

Nobuaki Shimoji

Full Text Available In this paper, we have evaluated the brightness of lightning leaders shown in a digital still image by applying the astronomical magnitude system. In order to analyze the only lightning leaders, these were extracted from the digital still image. For photometry of the lightning leaders, there is no a standard reference source such as Vega in astronomical photometry. Therefore, assuming the maximum pixel value 255 (in 256 levels as the brightness of a standard reference source, the magnitude of the lightning leaders was obtained. The result showed that the magnitude of the lightning leaders vary spatially (i.e. 2D spatial variability. Furthermore, the result suggested that a low current channel is high magnitude and a high current channel is low magnitude. Keywords: Lightning, Fechner’s law, Magnitude system, Astronomical photometry, Image analysis

CARMA SURVEY TOWARD INFRARED-BRIGHT NEARBY GALAXIES (STING). III. THE DEPENDENCE OF ATOMIC AND MOLECULAR GAS SURFACE DENSITIES ON GALAXY PROPERTIES

International Nuclear Information System (INIS)

Wong, Tony; Xue, Rui; Bolatto, Alberto D.; Fisher, David B.; Vogel, Stuart N.; Leroy, Adam K.; Blitz, Leo; Rosolowsky, Erik; Bigiel, Frank; Ott, Jürgen; Rahman, Nurur; Walter, Fabian

2013-01-01

We investigate the correlation between CO and H I emission in 18 nearby galaxies from the CARMA Survey Toward IR-Bright Nearby Galaxies (STING) at sub-kpc and kpc scales. Our sample, spanning a wide range in stellar mass and metallicity, reveals evidence for a metallicity dependence of the H I column density measured in regions exhibiting CO emission. Such a dependence is predicted by the equilibrium model of McKee and Krumholz, which balances H 2 formation and dissociation. The observed H I column density is often smaller than predicted by the model, an effect we attribute to unresolved clumping, although values close to the model prediction are also seen. We do not observe H I column densities much larger than predicted, as might be expected were there a diffuse H I component that did not contribute to H 2 shielding. We also find that the H 2 column density inferred from CO correlates strongly with the stellar surface density, suggesting that the local supply of molecular gas is tightly regulated by the stellar disk

Life-threatening motor vehicle crashes in bright sunlight

OpenAIRE

Redelmeier, Donald A.; Raza, Sheharyar

2017-01-01

Abstract Bright sunlight may create visual illusions that lead to driver error, including fallible distance judgment from aerial perspective. We tested whether the risk of a life-threatening motor vehicle crash was increased when driving in bright sunlight. This longitudinal, case-only, paired-comparison analysis evaluated patients hospitalized because of a motor vehicle crash between January 1, 1995 and December 31, 2014. The relative risk of a crash associated with bright sunlight was estim...

High-brightness fiber-coupled pump laser development

Science.gov (United States)

Price, Kirk; Karlsen, Scott; Leisher, Paul; Martinsen, Robert

2010-02-01

We report on the continued development of high brightness laser diode modules at nLIGHT Photonics. These modules, based on nLIGHT's PearlTM product platform, demonstrate excellence in output power, brightness, wavelength stabilization, and long wavelength performance. This system, based on 14 single emitters, is designed to couple diode laser light into a 105 μm fiber at an excitation NA of under 0.14. We demonstrate over 100W of optical power at 9xx nm with a diode brightness exceeding 20 MW/cm2-str with an operating efficiency of approximately 50%. Additional results show over 70W of optical coupled at 8xx nm. Record brilliance at wavelengths 14xx nm and longer will also be demonstrated, with over 15 W of optical power with a beam quality of 7.5 mm-mrad. These results of high brightness, high efficiency, and wavelength stabilization demonstrate the pump technology required for next generation solid state and fiber lasers.

AGN classification for X-ray sources in the 105 month Swift/BAT survey

Science.gov (United States)

Masetti, N.; Bassani, L.; Palazzi, E.; Malizia, A.; Stephen, J. B.; Ubertini, P.

2018-03-01

We here provide classifications for 8 hard X-ray sources listed as 'unknown AGN' in the 105 month Swift/BAT all-sky survey catalogue (Oh et al. 2018, ApJS, 235, 4). The corresponding optical spectra were extracted from the 6dF Galaxy Survey (Jones et al. 2009, MNRAS, 399, 683).

Automated detection of extended sources in radio maps: progress from the SCORPIO survey

Science.gov (United States)

Riggi, S.; Ingallinera, A.; Leto, P.; Cavallaro, F.; Bufano, F.; Schillirò, F.; Trigilio, C.; Umana, G.; Buemi, C. S.; Norris, R. P.

2016-08-01

Automated source extraction and parametrization represents a crucial challenge for the next-generation radio interferometer surveys, such as those performed with the Square Kilometre Array (SKA) and its precursors. In this paper, we present a new algorithm, called CAESAR (Compact And Extended Source Automated Recognition), to detect and parametrize extended sources in radio interferometric maps. It is based on a pre-filtering stage, allowing image denoising, compact source suppression and enhancement of diffuse emission, followed by an adaptive superpixel clustering stage for final source segmentation. A parametrization stage provides source flux information and a wide range of morphology estimators for post-processing analysis. We developed CAESAR in a modular software library, also including different methods for local background estimation and image filtering, along with alternative algorithms for both compact and diffuse source extraction. The method was applied to real radio continuum data collected at the Australian Telescope Compact Array (ATCA) within the SCORPIO project, a pathfinder of the Evolutionary Map of the Universe (EMU) survey at the Australian Square Kilometre Array Pathfinder (ASKAP). The source reconstruction capabilities were studied over different test fields in the presence of compact sources, imaging artefacts and diffuse emission from the Galactic plane and compared with existing algorithms. When compared to a human-driven analysis, the designed algorithm was found capable of detecting known target sources and regions of diffuse emission, outperforming alternative approaches over the considered fields.

Analysis of a high brightness photo electron beam with self field and wake field effects

International Nuclear Information System (INIS)

Parsa, Z.

1991-01-01

High brightness sources are the basic ingredients in the new accelerator developments such as Free-Electron Laser experiments. The effects of the interactions between the highly charged particles and the fields in the accelerating structure, e.g. R.F., Space charge and Wake fields can be detrimental to the beam and the experiments. We present and discuss the formulation used, some simulation and results for the Brookhaven National Laboratory high brightness beam that illustrates effects of the accelerating field, space charge forces (e.g. due to self field of the bunch), and the wake field (e.g. arising from the interaction of the cavity surface and the self field of the bunch)

The surface brightness of spiral galaxies

International Nuclear Information System (INIS)

Phillipps, S.; Disney, M.

1983-01-01

It is proposed that Freeman's discovery that the extrapolated central surface brightness of spiral galaxies is approximately constant can be simply explained if the galaxies contain a spheroidal component which dominates the light in their outer isophotes. Calculations of an effective central surface brightness indicate a wide spread of values. This requires either a wide spread in disc properties or significant spheroidal components or, most probably, both. (author)

The effect of bright lines in environmental risk communication

International Nuclear Information System (INIS)

Wilson, K.N.; Desvousges, W.H.; Smith, K.V.; Payne, J.

1993-01-01

Bright lines in environmental risk communication refer to the specific levels at which an environmental risk becomes a serious health threat and action should be taken to mitigate its effects. This study examined the effect of ''bright lines'' in risk communication by emphasizing the radon exposure threshold level of 4 picocuries per liter. Specifically, the authors developed a computer-assisted interview containing bright-line versions of risk information. The bright-line version contained a range of possible radon levels, the corresponding number of estimated lung cancer cases, the relative health risk from radon compared to other health risks, and the EPA guidelines for mitigating levels above 4 picocuries in the home. The non-bright line version was identical to the bright-line version, except it did not include the EPA's mitigation recommendations. Effect measures included respondents' change in perceived risk after reading their materials, intended testing behavior, and advice to their neighbor for a specified radon level either above or below the 4 picocury threshold level. This paper discusses broader policy implications for designing effective risk communication programs

HI-bearing Ultra Diffuse Galaxies in the ALFALFA Survey

Science.gov (United States)

Leisman, Lukas; Janowiecki, Steven; Jones, Michael G.; ALFALFA Almost Darks Team

2018-01-01

The Arecibo Legacy Fast ALFA (Arecibo L-band Feed Array) extragalactic HI survey, with over 30,000 high significance extragalactic sources, is well positioned to locate gas-bearing, low surface brightness sources missed by optical detection algorithms. We investigate the nature of a population of HI-bearing sources in ALFALFA with properties similar to "ultra-diffuse" galaxies (UDGs): galaxies with stellar masses of dwarf galaxies, but radii of L* galaxies. These "HI-bearing ultra-diffuse" sources (HUDS) constitute a small, but pertinent, fraction of the dwarf-mass galaxies in ALFALFA. They are bluer and have more irregular morphologies than the optically-selected UDGs found in clusters, and they appear to be gas-rich for their stellar mass, indicating low star formation efficiency. To illuminate potential explanations for the extreme properties of these sources we explore their environments and estimate their halo properties. We conclude that environmental mechanism are unlikely the cause of HUDS' properties, as they exist in environments equivalent to that of the other ALFALFA sources of similar HI-masses, however, we do find some suggestion that these HUDS may reside in high spin parameter halos, a potential explanation for their "ultra-diffuse" nature.

Bright boys the making of information technology

CERN Document Server

Green, Tom

2010-01-01

Everything has a beginning. None was more profound-and quite as unexpected-than Information Technology. Here for the first time is the untold story of how our new age came to be and the bright boys who made it happen. What began on the bare floor of an old laundry building eventually grew to rival in size the Manhattan Project. The unexpected consequence of that journey was huge---what we now know as Information Technology. For sixty years the bright boys have been totally anonymous while their achievements have become a way of life for all of us. "Bright Boys" brings them home. By 1950 they'd

The Galactic Distribution of Massive Star Formation from the Red MSX Source Survey

Science.gov (United States)

Figura, Charles C.; Urquhart, J. S.

2013-01-01

Massive stars inject enormous amounts of energy into their environments in the form of UV radiation and molecular outflows, creating HII regions and enriching local chemistry. These effects provide feedback mechanisms that aid in regulating star formation in the region, and may trigger the formation of subsequent generations of stars. Understanding the mechanics of massive star formation presents an important key to understanding this process and its role in shaping the dynamics of galactic structure. The Red MSX Source (RMS) survey is a multi-wavelength investigation of ~1200 massive young stellar objects (MYSO) and ultra-compact HII (UCHII) regions identified from a sample of colour-selected sources from the Midcourse Space Experiment (MSX) point source catalog and Two Micron All Sky Survey. We present a study of over 900 MYSO and UCHII regions investigated by the RMS survey. We review the methods used to determine distances, and investigate the radial galactocentric distribution of these sources in context with the observed structure of the galaxy. The distribution of MYSO and UCHII regions is found to be spatially correlated with the spiral arms and galactic bar. We examine the radial distribution of MYSOs and UCHII regions and find variations in the star formation rate between the inner and outer Galaxy and discuss the implications for star formation throughout the galactic disc.

Star formation and the surface brightness of spiral galaxies

International Nuclear Information System (INIS)

Phillipps, S.; Disney, M.

1985-01-01

The (blue) surface brightness of spiral galaxies is significantly correlated with their Hα linewidth. This can be most plausibly interpreted as a correlation of surface brightness with star formation rate. There is also a significant difference in surface brightness between galaxies forming stars in a grand design spiral pattern and those with floc star formation regions. (author)

AERIAL SURVEYING UAV BASED ON OPEN-SOURCE HARDWARE AND SOFTWARE

Directory of Open Access Journals (Sweden)

J. Mészáros

2012-09-01

Full Text Available In the last years the functionality and type of UAV-systems increased fast, but unfortunately these systems are hardly available for researchers in some cases. A simple and low-cost solution was developed to build an autonomous aerial surveying airplane, which can fulfil the necessities (aerial photographs with very-high resolution of other departments at the university and very useful and practical for teaching photogrammetry.. The base was a commercial, remote controlled model airplane and an open-source GPS/IMU system (MatrixPilot was adapted to achieve the semi-automatic or automatic stabilization and navigation of the model airplane along predefined trajectory. The firmware is completely open-source and easily available on the website of the project. The first used camera system was a low-budget, low-quality video camera, which could provide only 1.2 megapixel photographs or low resolution video depending on the light conditions and the desired spatial resolution. A field measurement test was carried out with the described system: the aerial surveying of an undiscovered archaeological site, signed by a crop-mark in mountain Pilis (Hungary.

The optical counterpart of the bright X-ray transient Swift J1745-26

NARCIS (Netherlands)

Muñoz-Darias, T.; de Ugarte Postigo, A.; Russell, D.M.; Guziy, S.; Gorosabel, J.; Casares, J.; Armas Padilla, M.; Charles, P.A.; Fender, R.P.; Belloni, T.M.; Lewis, F.; Motta, S.; Castro-Tirado, A.; Mundell, C.G.; Sánchez-Ramirez, R.; Thöne, C.C.

2013-01-01

We present a 30-day monitoring campaign of the optical counterpart of the bright X-ray transient Swift J1745−26, starting only 19 min after the discovery of the source. We observe the system peaking at i′ ∼ 17.6 on day six (MJD 561 92) to then decay at a rate of ∼0.04 mag d−1. We show that the

Joint Source-Channel Decoding of Variable-Length Codes with Soft Information: A Survey

Directory of Open Access Journals (Sweden)

Pierre Siohan

2005-05-01

Full Text Available Multimedia transmission over time-varying wireless channels presents a number of challenges beyond existing capabilities conceived so far for third-generation networks. Efficient quality-of-service (QoS provisioning for multimedia on these channels may in particular require a loosening and a rethinking of the layer separation principle. In that context, joint source-channel decoding (JSCD strategies have gained attention as viable alternatives to separate decoding of source and channel codes. A statistical framework based on hidden Markov models (HMM capturing dependencies between the source and channel coding components sets the foundation for optimal design of techniques of joint decoding of source and channel codes. The problem has been largely addressed in the research community, by considering both fixed-length codes (FLC and variable-length source codes (VLC widely used in compression standards. Joint source-channel decoding of VLC raises specific difficulties due to the fact that the segmentation of the received bitstream into source symbols is random. This paper makes a survey of recent theoretical and practical advances in the area of JSCD with soft information of VLC-encoded sources. It first describes the main paths followed for designing efficient estimators for VLC-encoded sources, the key component of the JSCD iterative structure. It then presents the main issues involved in the application of the turbo principle to JSCD of VLC-encoded sources as well as the main approaches to source-controlled channel decoding. This survey terminates by performance illustrations with real image and video decoding systems.

Joint Source-Channel Decoding of Variable-Length Codes with Soft Information: A Survey

Science.gov (United States)

Guillemot, Christine; Siohan, Pierre

2005-12-01

Multimedia transmission over time-varying wireless channels presents a number of challenges beyond existing capabilities conceived so far for third-generation networks. Efficient quality-of-service (QoS) provisioning for multimedia on these channels may in particular require a loosening and a rethinking of the layer separation principle. In that context, joint source-channel decoding (JSCD) strategies have gained attention as viable alternatives to separate decoding of source and channel codes. A statistical framework based on hidden Markov models (HMM) capturing dependencies between the source and channel coding components sets the foundation for optimal design of techniques of joint decoding of source and channel codes. The problem has been largely addressed in the research community, by considering both fixed-length codes (FLC) and variable-length source codes (VLC) widely used in compression standards. Joint source-channel decoding of VLC raises specific difficulties due to the fact that the segmentation of the received bitstream into source symbols is random. This paper makes a survey of recent theoretical and practical advances in the area of JSCD with soft information of VLC-encoded sources. It first describes the main paths followed for designing efficient estimators for VLC-encoded sources, the key component of the JSCD iterative structure. It then presents the main issues involved in the application of the turbo principle to JSCD of VLC-encoded sources as well as the main approaches to source-controlled channel decoding. This survey terminates by performance illustrations with real image and video decoding systems.

The stakeholders' project in neuropsychological report writing: a survey of neuropsychologists' and referral sources' views of neuropsychological reports.

Science.gov (United States)

Postal, Karen; Chow, Clifton; Jung, Sharon; Erickson-Moreo, Kalen; Geier, Flannery; Lanca, Margaret

2018-04-01

Though some neuropsychological groups have proposed criteria and suggestions for clinical report writing there has never been professional consensus or accepted published guidelines on how to write reports. Given the paucity of guidelines and the evolving practice climate, we sought to survey neuropsychologists and referral source stakeholders to understand current report writing practices. The data were collected in two SurveyMonkey surveys via professional list servs, email, and LinkedIn clinical interest groups. Results of the survey indicate many neuropsychologists spend multiple hours writing reports that they believe will not be read completely by stakeholders. A striking 73% of referral sources reported slow turnaround time of neuropsychological reports negatively affected their patient care. Referral sources reported they value the diagnosis/impression and recommendations sections the most; in contrast, they did not find the history, behavioral observations, emotional functioning, or descriptions of cognitive domains sections as useful. The survey findings highlight the disjuncture between what neuropsychologists typically do in their practice of report writing versus what they believe is useful for patients and referral sources. The survey also highlights differences between writing practices of neuropsychologists and what referral sources identify as the most valuable aspects of reports to assist them in caring for their patients.

THE NATURE OF THE BRIGHT ULX X-2 IN NGC 3921: A CHANDRA POSITION AND HST CANDIDATE COUNTERPART

Energy Technology Data Exchange (ETDEWEB)

Jonker, P. G.; Heida, M.; Torres, M. A. P.; Ratti, E. M. [SRON, Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht (Netherlands); Miller-Jones, J. C. A. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, WA 6845 (Australia); Fabian, A. C.; Walton, D. J. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Miniutti, G. [Centro de Astrobiologia (CSIC-INTA), Departamento de Astrofisica, ESA, P.O. Box 78, E-28691 Villanueva de la Canada, Madrid (Spain); Roberts, T. P., E-mail: p.jonker@sron.nl [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)

2012-10-10

We report on Chandra observations of the bright ultraluminous X-ray (ULX) source in NGC 3921. Previous XMM-Newton observations reported in the literature show the presence of a bright ULX at a 0.5-10 keV luminosity of 2 Multiplication-Sign 10{sup 40} erg s{sup -1}. Our Chandra observation finds the source at a lower luminosity of Almost-Equal-To 8 Multiplication-Sign 10{sup 39} erg s{sup -1}; furthermore, we provide a Chandra position of the ULX accurate to 0.''7 at 90% confidence. The X-ray variability makes it unlikely that the high luminosity is caused by several separate X-ray sources. In three epochs of archival Hubble Space Telescope observations, we find a candidate counterpart to the ULX. There is direct evidence for variability between the two epochs of WFPC2 F814W observations with the observation obtained in 2000 showing a brighter source. Furthermore, converting the 1994 F336W and 2000 F300W WFPC2 and the 2010 F336W WFC3 observations to the Johnson U-band filter assuming a spectral type of O7I, we find evidence for a brightening of the U-band light in 2000. Using the higher resolution WFC3 observations, we resolve the candidate counterpart into two sources of similar color. We discuss the nature of the ULX and the probable association with the optical counterpart(s). Finally, we investigate a potential new explanation for some (bright) ULXs as the decaying stages of flares caused by the tidal disruption of a star by a recoiled supermassive black hole. However, we find that there should be at most only one of such systems within z = 0.08.

The surface brightness of spiral galaxies

International Nuclear Information System (INIS)

Disney, M.; Phillipps, S.

1985-01-01

The intrinsic surface brightness Ssub(e) of 500 disc galaxies (0<=T<=9) drawn from the Second Reference Catalogue is computed and it is shown that Ssub(e) does not correlate significantly with Msub(B), (B-V) or type. This is consistent with the notion that there is a heavy selection bias in favour of disc galaxies with that particular surface brightness which allows inclusion in the catalogue over the largest volume of space. (author)

SURFACE PHOTOMETRY OF LOW SURFACE BRIGHTNESS GALAXIES

NARCIS (Netherlands)

DEBLOK, WJG; VANDERHULST, JM; BOTHUN, GD

1995-01-01

Low surface brightness (LSB) galaxies are galaxies dominated by an exponential disc whose central surface brightness is much fainter than the value of mu(B)(0) = 21.65 +/- 0.30 mag arcsec(-2) found by Freeman. In this paper we present broadband photometry of a sample of 21 late-type LSB galaxies.

Atomic physics with high-brightness synchrotron x-ray sources

International Nuclear Information System (INIS)

Jones, K.W.; Johnson, B.M.; Meron, M.

1985-11-01

A description of atomic physics experiments that we intend to carry out at the National Synchrotron Light Source is given. Emphasis is given to work that investigates the properties of multiply charged ions. The use of a synchrotron storage ring for highly charged heavy ions is proposed as a way to produce high current beams which will make possible experiments to study the photoexcitation and ionization of multiply charged ions for the first time. Experiments along the same lines which are feasible at the proposed Advanced Light Source are considered briefly. 7 refs., 2 figs

Development of Langmuir probe diagnostic system for 13.56 MHz plasma sources

International Nuclear Information System (INIS)

Ranjini, K.; Nabhiraj, P.Y.; Mallik, C.; Bhandari, R.K.

2006-01-01

A work on development of high brightness ion source has been started recently. Plasma parameters are strongly linked to the brightness of the ion beams produced from the ion sources. A self compensated Langmuir probe and related automation system for the measurement of plasma parameters is developed. This paper describes design of the probe, software, hardware and the results. (author)

A cold atom electron source

NARCIS (Netherlands)

Taban, G.

2009-01-01

Pulsed bright electron sources offer the possibility to study the structure of matter in great spatial and temporal detail. An example of an indirect method is to generate hard X-ray °ashes with high brilliance, a new Free Electron Laser facility is under construction. It requires an electron source

Characterizing Walk Trips in communities by Using Data from 2009 National Household Travel Survey, American Community Survey, and Other Sources

Energy Technology Data Exchange (ETDEWEB)

Hwang, Ho-Ling [ORNL; Reuscher, Tim [Macrosys; Wilson, Daniel W [ORNL; Murakami, Elaine [FHWA USDOT

2013-01-01

Non-motorized travel (i.e. walking and bicycling) are of increasing interest to the transportation profession, especially in context with energy consumption, reducing vehicular congestion, urban development patterns, and promotion of healthier life styles. This research project aimed to identify factors impacting the amount of travel for both walk and bike trips at the Census block group or tract level, using several public and private data sources. The key survey of travel behavior is the 2009 National Household Travel Survey (NHTS) which had over 87,000 walk trips for persons 16 and over, and over 6000 bike trips for persons 16 and over. The NHTS, in conjunction with the Census Bureau s American Community Survey, street density measures using Census Bureau TIGER, WalkScore , Nielsen Claritas employment estimates, and several other sources were used for this study. Stepwise Logistic Regression modeling techniques as well as Discriminant Analysis were applied using the integrated data set. While the models performed reasonably well for walk trips, travel by bike was abandoned due to sparseness of data. This paper discusses data sources utilized and modeling processes conducted under this study. It also presents a summary of findings and addresses data challenges and lesson-learned from this research effort.

Optical Performance of Carbon-Nanotube Electron Sources

International Nuclear Information System (INIS)

Jonge, Niels de; Allioux, Myriam; Oostveen, Jim T.; Teo, Kenneth B. K.; Milne, William I.

2005-01-01

The figure of merit for the electron optical performance of carbon-nanotube (CNT) electron sources is presented. This figure is given by the relation between the reduced brightness and the energy spread in the region of stable emission. It is shown experimentally that a CNT electron source exhibits a highly stable emission process that follows the Fowler-Nordheim theory for field emission, fixing the relationship among the energy spread, the current, and the radius. The performance of the CNT emitter under realistic operating conditions is compared with state-of-the-art electron point sources. It is demonstrated that the reduced brightness is a function of the tunneling parameter, a measure of the energy spread at low temperatures, only, independent of the geometry of the emitter

The surface brightness of spiral galaxies: Pt. 4

International Nuclear Information System (INIS)

Phillipps, S.; Disney, M.; Ohio State Univ., Columbus

1988-01-01

Using measurements from IRAS correlations are found between optical surface brightness and both infrared-to-optical flux ratio and infrared colour temperature, in the sense that galaxies with high surface brightness have higher FIR emission and higher temperatures. (author)

Bright point study

International Nuclear Information System (INIS)

Tang, F.; Harvey, K.; Bruner, M.; Kent, B.; Antonucci, E.

1982-01-01

Transition region and coronal observations of bright points by instruments aboard the Solar Maximum Mission and high resolution photospheric magnetograph observations on September 11, 1980 are presented. A total of 31 bipolar ephemeral regions were found in the photosphere from birth in 9.3 hours of combined magnetograph observations from three observatories. Two of the three ephemeral regions present in the field of view of the Ultraviolet Spectrometer-Polarimeter were observed in the C IV 1548 line. The unobserved ephemeral region was determined to be the shortest-lived (2.5 hr) and lowest in magnetic flux density (13G) of the three regions. The Flat Crystal Spectrometer observed only low level signals in the O VIII 18.969 A line, which were not statistically significant to be positively identified with any of the 16 ephemeral regions detected in the photosphere. In addition, the data indicate that at any given time there lacked a one-to-one correspondence between observable bright points and photospheric ephemeral regions, while more ephemeral regions were observed than their counterparts in the transition region and the corona

Giant Low Surface Brightness Galaxies

Science.gov (United States)

Mishra, Alka; Kantharia, Nimisha G.; Das, Mousumi

2018-04-01

In this paper, we present radio observations of the giant low surface brightness (LSB) galaxies made using the Giant Metrewave Radio Telescope (GMRT). LSB galaxies are generally large, dark matter dominated spirals that have low star formation efficiencies and large HI gas disks. Their properties suggest that they are less evolved compared to high surface brightness galaxies. We present GMRT emission maps of LSB galaxies with an optically-identified active nucleus. Using our radio data and archival near-infrared (2MASS) and near-ultraviolet (GALEX) data, we studied morphology and star formation efficiencies in these galaxies. All the galaxies show radio continuum emission mostly associated with the centre of the galaxy.

Helmholtz bright and boundary solitons

International Nuclear Information System (INIS)

Christian, J M; McDonald, G S; Chamorro-Posada, P

2007-01-01

We report, for the first time, exact analytical boundary solitons of a generalized cubic-quintic nonlinear Helmholtz (NLH) equation. These solutions have a linked-plateau topology that is distinct from conventional dark soliton solutions; their amplitude and intensity distributions are spatially delocalized and connect regions of finite and zero wave-field disturbances (suggesting also the classification as 'edge solitons'). Extensive numerical simulations compare the stability properties of recently derived Helmholtz bright solitons, for this type of polynomial nonlinearity, to those of the new boundary solitons. The latter are found to possess a remarkable stability characteristic, exhibiting robustness against perturbations that would otherwise lead to the destabilizing of their bright-soliton counterparts

High-intensity sources for light ions

International Nuclear Information System (INIS)

Leung, K.N.

1995-10-01

The use of the multicusp plasma generator as a source of light ions is described. By employing radio-frequency induction discharge, the performance of the multicusp source is greatly improved, both in lifetime and in high brightness H + and H - beam production. A new technique for generating multiply-charged ions in this type of ion source is also presented

A control system of a mini survey facility for photometric monitoring

Science.gov (United States)

Tsutsui, Hironori; Yanagisawa, Kenshi; Izumiura, Hideyuki; Shimizu, Yasuhiro; Hanaue, Takumi; Ita, Yoshifusa; Ichikawa, Takashi; Komiyama, Takahiro

2016-08-01

We have built a control system for a mini survey facility dedicated to photometric monitoring of nearby bright (Kdome and a small (30-mm aperture) wide-field (5 × 5 sq. deg. field of view) infrared (1.0-2.5 microns) camera on an equatorial fork mount, as well as power sources and other associated equipment. All the components other than the camera are controlled by microcomputerbased I/O boards that were developed in-house and are in many of the open-use instruments in our observatory. We present the specifications and configuration of the facility hardware, as well as the structure of its control software.

Brightness waves of electroluminescence in ZnO:La electroluminor

International Nuclear Information System (INIS)

Bhushan, S.; Pandey, A.N.; Kaza, Balakrishna Rao

1979-01-01

A cryostat for the measurement of different luminescent characteristics from liquid N 2 temperature to above has been fabricated. Using this cryostat brightness waves due to sinusoidal excitations for ZnO:La electroluminor (EL) has been studied at different temperatures from -168deg C. Brightness waves for this system consist of two primary peaks during each cycle of excitation. Each primary peak is associated with a secondary peak. This secondary peak at -168deg C exists at the left arm of the primary peak. As the temperature is increased to 18deg C it moves towards the right arm of the primary peak. At an intermediate temperature the secondary peaks are most pronounced. Possible mechanism for these phenomena have been discussed. Temperature dependence of time averaged EL brightness for this system has also been studied and three peaks have been found. The results of brightness waves have also been discussed in the light of temperature dependence of time averaged EL brightness. (auth.)

VizieR Online Data Catalog: UV-bright quasars (Syphers+, 2009)

Science.gov (United States)

Syphers, D.; Anderson, S. F.; Zheng, W.; Haggard, D.; Meiksin, A.; Schneider, D. P.; York, D. G.

2010-03-01

Absorption along quasar sightlines remains among the most sensitive direct measures of HeII reionization in much of the intergalactic medium (IGM). Until recently, fewer than a half-dozen unobscured quasar sightlines suitable for the HeII Gunn-Peterson test were known; although these handful demonstrated great promise, the small sample size limited confidence in cosmological inferences. We have recently added nine more such clean HeII quasars, exploiting Sloan Digital Sky Survey (SDSS) quasar samples, broadband ultraviolet (UV) imaging from Galaxy Evolution Explorer (GALEX), and high-yield UV spectroscopic confirmations from Hubble Space Telescope (HST). Here we markedly expand this approach by cross-correlating SDSS DR7 and GALEX GR4+5 to catalog 428 SDSS and 165 other quasars with z>2.78 having likely (~70%) GALEX detections, suggesting they are bright into the far-UV. Reconnaissance HST Cycle 16 Supplemental prism data for 29 of these new quasar-GALEX matches spectroscopically confirm 17 as indeed far-UV bright. At least 10 of these confirmations have clean sightlines all the way down to HeII Lyα, substantially expanding the number of known clean HeII quasars, and reaffirming the order of magnitude enhanced efficiency of our selection technique. Combined confirmations from this and our past programs yield more than 20 HeII quasars, quintupling the sample. These provide substantial progress toward a sample of HeII quasar sightlines large enough, and spanning a sufficient redshift range, to enable statistical IGM studies that may avoid individual object peculiarity and sightline variance. Our expanded catalog of hundreds of high-likelihood far-UV-bright QSOs additionally will be useful for understanding the extreme-UV properties of the quasars themselves. (2 data files).

LIGHT SOURCE: A simulation study of Tsinghua Thomson scattering X-ray source

Science.gov (United States)

Tang, Chuan-Xiang; Li, Ren-Kai; Huang, Wen-Hui; Chen, Huai-Bi; Du, Ying-Chao; Du, Qiang; Du, Tai-Bin; He, Xiao-Zhong; Hua, Jian-Fei; Lin, Yu-Zhen; Qian, Hou-Jun; Shi, Jia-Ru; Xiang, Dao; Yan, Li-Xin; Yu, Pei-Cheng

2009-06-01

Thomson scattering X-ray sources are compact and affordable facilities that produce short duration, high brightness X-ray pulses enabling new experimental capacities in ultra-fast science studies, and also medical and industrial applications. Such a facility has been built at the Accelerator Laboratory of Tsinghua University, and upgrade is in progress. In this paper, we present a proposed layout of the upgrade with design parameters by simulation, aiming at high X-ray pulses flux and brightness, and also enabling advanced dynamics studies and applications of the electron beam. Design and construction status of main subsystems are also presented.

The DES Bright Arcs Survey: Hundreds of Candidate Strongly Lensed Galaxy Systems from the Dark Energy Survey Science Verification and Year 1 Observations

Energy Technology Data Exchange (ETDEWEB)

Diehl, H. T.; Buckley-Geer, E. J.; Lindgren, K. A.; Nord, B.; Gaitsch, H.; Gaitsch, S.; Lin, H.; Allam, S.; Odden, C.; Pellico, A.; Tucker, D. L.; Kuropatkin, N.; Soares-Santos, M. [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Collett, T. E. [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom); Furlanetto, C.; Nightingale, J. [University of Nottingham, School of Physics and Astronomy, Nottingham NG7 2RD (United Kingdom); Gill, M. S. S. [SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); More, A. [Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Costa, L. N. da; Neto, A. Fausti, E-mail: diehl@fnal.gov [Laboratório Interinstitucional de e-Astronomia—LIneA, Rua Gal. José Cristino 77, Rio de Janeiro, RJ—20921-400 (Brazil); Collaboration: DES Collaboration; and others

2017-09-01

We report the results of searches for strong gravitational lens systems in the Dark Energy Survey (DES) Science Verification and Year 1 observations. The Science Verification data span approximately 250 sq. deg. with a median i -band limiting magnitude for extended objects (10 σ ) of 23.0. The Year 1 data span approximately 2000 sq. deg. and have an i -band limiting magnitude for extended objects (10 σ ) of 22.9. As these data sets are both wide and deep, they are particularly useful for identifying strong gravitational lens candidates. Potential strong gravitational lens candidate systems were initially identified based on a color and magnitude selection in the DES object catalogs or because the system is at the location of a previously identified galaxy cluster. Cutout images of potential candidates were then visually scanned using an object viewer and numerically ranked according to whether or not we judged them to be likely strong gravitational lens systems. Having scanned nearly 400,000 cutouts, we present 374 candidate strong lens systems, of which 348 are identified for the first time. We provide the R.A. and decl., the magnitudes and photometric properties of the lens and source objects, and the distance (radius) of the source(s) from the lens center for each system.

Stunningly bright optical emission

Science.gov (United States)

Heinke, Craig O.

2017-12-01

The detection of bright, rapid optical pulsations from pulsar PSR J1023+0038 have provided a surprise for researchers working on neutron stars. This discovery poses more questions than it answers and will spur on future work and instrumentation.

A Survey of Open-Source UAV Flight Controllers and Flight Simulators

DEFF Research Database (Denmark)

Ebeid, Emad Samuel Malki; Skriver, Martin; Terkildsen, Kristian Husum

2018-01-01

, which are all tightly linked to the UAV flight controller hardware and software. The lack of standardization of flight controller architectures and the use of proprietary closed-source flight controllers on many UAV platforms, however, complicates this work: solutions developed for one flight controller...... may be difficult to port to another without substantial extra development and testing. Using open-source flight controllers mitigates some of these challenges and enables other researchers to validate and build upon existing research. This paper presents a survey of the publicly available open...

Synchrotron source may have a bright future

International Nuclear Information System (INIS)

Rotman, D.

1988-01-01

If all goes well on Capitol Hill, construction of the proposed $456 million 7-GeV Advanced Photon Source (APS) at Argonne National Laboratory (Argonne, IL) could start next year. President Ronald Reagan's fiscal 1989 federal budget proposed $6 million for the construction and the request now awaits congressional approval. The long-planned facility will emit X rays that are 10,000 times more brilliant than any currently produced for research purposes. According to many scientists, it will be a major boost to a variety of fields, including chemistry, materials science and medicine. Because of the brilliance of its X rays, the APS facility will permit experiments that reveal atomic and molecular structures faster and in greater detail than is now possible

Bright Merger-nova Emission Powered by Magnetic Wind from a Newborn Black Hole

Science.gov (United States)

Ma, Shuai-Bing; Lei, Wei-Hua; Gao, He; Xie, Wei; Chen, Wei; Zhang, Bing; Wang, Ding-Xiong

2018-01-01

Mergers of neutron star–neutron star (NS–NS) or neutron star–black hole (NS–BH) binaries are candidate sources of gravitational waves (GWs). At least a fraction of the merger remnants should be a stellar mass BH with sub-relativistic ejecta. A collimated jet is launched via the Blandford–Znajek mechanism from the central BH to trigger a short gamma-ray burst (sGRB). At the same time, a near-isotropic wind may be driven by the Blandford–Payne mechanism (BP). In previous work, additional energy injection to the ejecta from the BP mechanism was ignored, and radioactive decay has long been thought to be the main source of the kilonova energy. In this Letter, we propose that the wind driven by the BP mechanism from the newborn BH’s disk can heat up and push the ejecta during the prompt emission phase or even at late times when there is fall-back accretion. Such a BP-powered merger-nova could be bright in the optical band even for a low-luminosity sGRB. The detection of a GW merger event with a BH clearly identified as a remnant, accompanied by a bright merger-nova, would provide robust confirmation of our model.

LARGER PLANET RADII INFERRED FROM STELLAR ''FLICKER'' BRIGHTNESS VARIATIONS OF BRIGHT PLANET-HOST STARS

International Nuclear Information System (INIS)

Bastien, Fabienne A.; Stassun, Keivan G.; Pepper, Joshua

2014-01-01

Most extrasolar planets have been detected by their influence on their parent star, typically either gravitationally (the Doppler method) or by the small dip in brightness as the planet blocks a portion of the star (the transit method). Therefore, the accuracy with which we know the masses and radii of extrasolar planets depends directly on how well we know those of the stars, the latter usually determined from the measured stellar surface gravity, log g. Recent work has demonstrated that the short-timescale brightness variations ( f licker ) of stars can be used to measure log g to a high accuracy of ∼0.1-0.2 dex. Here, we use flicker measurements of 289 bright (Kepmag < 13) candidate planet-hosting stars with T eff = 4500-6650 K to re-assess the stellar parameters and determine the resulting impact on derived planet properties. This re-assessment reveals that for the brightest planet-host stars, Malmquist bias contaminates the stellar sample with evolved stars: nearly 50% of the bright planet-host stars are subgiants. As a result, the stellar radii, and hence the radii of the planets orbiting these stars, are on average 20%-30% larger than previous measurements had suggested

Beam brightness calculation for analytical and empirical distribution functions

International Nuclear Information System (INIS)

Myers, T.J.; Boulais, K.A.; O, Y.S.; Rhee, M.J.

1992-01-01

The beam brightness, a figure of merit for a beam quality useful for high-current low-emittance beams, was introduced by van Steenbergen as B = I/V 4 , where I is the beam current and V 4 is the hypervolume in the four-dimensional trace space occupied by the beam particles. Customarily, the brightness is expressed in terms of the product of emittances ε x ε y as B = ηI/(π 2 ε x ε y ), where η is a form factor of order unity which depends on the precise definition of emittance and hypervolume. Recently, a refined definition of the beam brightness based on the arithmetic mean value defined in statistics is proposed. The beam brightness is defined as B triple-bond 4 > = I -1 ∫ ρ 4 2 dxdydx'dy', where I is the beam current given by I ∫ ρ 4 dxdydx'dy'. Note that in this definition, neither the hypervolume V 4 nor the emittance, are explicitly used; the brightness is determined solely by the distribution function. Brightnesses are unambiguously calculated and expressed analytically in terms of the respective beam current and effective emittance for a few commonly used distribution functions, including Maxwellian and water-bag distributions. Other distributions of arbitrary shape frequently encountered in actual experiments are treated numerically. The resulting brightnesses are expressed in the form B = ηI/(π 2 ε x ε y ), and η is found to be weakly dependent on the form of velocity distribution as well as spatial distribution

Color and emotion: effects of hue, saturation, and brightness.

Science.gov (United States)

Wilms, Lisa; Oberfeld, Daniel

2017-06-13

Previous studies on emotional effects of color often failed to control all the three perceptual dimensions of color: hue, saturation, and brightness. Here, we presented a three-dimensional space of chromatic colors by independently varying hue (blue, green, red), saturation (low, medium, high), and brightness (dark, medium, bright) in a factorial design. The 27 chromatic colors, plus 3 brightness-matched achromatic colors, were presented via an LED display. Participants (N = 62) viewed each color for 30 s and then rated their current emotional state (valence and arousal). Skin conductance and heart rate were measured continuously. The emotion ratings showed that saturated and bright colors were associated with higher arousal. The hue also had a significant effect on arousal, which increased from blue and green to red. The ratings of valence were the highest for saturated and bright colors, and also depended on the hue. Several interaction effects of the three color dimensions were observed for both arousal and valence. For instance, the valence ratings were higher for blue than for the remaining hues, but only for highly saturated colors. Saturated and bright colors caused significantly stronger skin conductance responses. Achromatic colors resulted in a short-term deceleration in the heart rate, while chromatic colors caused an acceleration. The results confirm that color stimuli have effects on the emotional state of the observer. These effects are not only determined by the hue of a color, as is often assumed, but by all the three color dimensions as well as their interactions.

Quantitative Brightness Analysis of Fluorescence Intensity Fluctuations in E. Coli.

Directory of Open Access Journals (Sweden)

Kwang-Ho Hur

Full Text Available The brightness measured by fluorescence fluctuation spectroscopy specifies the average stoichiometry of a labeled protein in a sample. Here we extended brightness analysis, which has been mainly applied in eukaryotic cells, to prokaryotic cells with E. coli serving as a model system. The small size of the E. coli cell introduces unique challenges for applying brightness analysis that are addressed in this work. Photobleaching leads to a depletion of fluorophores and a reduction of the brightness of protein complexes. In addition, the E. coli cell and the point spread function of the instrument only partially overlap, which influences intensity fluctuations. To address these challenges we developed MSQ analysis, which is based on the mean Q-value of segmented photon count data, and combined it with the analysis of axial scans through the E. coli cell. The MSQ method recovers brightness, concentration, and diffusion time of soluble proteins in E. coli. We applied MSQ to measure the brightness of EGFP in E. coli and compared it to solution measurements. We further used MSQ analysis to determine the oligomeric state of nuclear transport factor 2 labeled with EGFP expressed in E. coli cells. The results obtained demonstrate the feasibility of quantifying the stoichiometry of proteins by brightness analysis in a prokaryotic cell.

SPECTRAL PROPERTIES OF BRIGHT FERMI-DETECTED BLAZARS IN THE GAMMA-RAY BAND

International Nuclear Information System (INIS)

Abdo, A. A.; Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W.; Bouvier, A.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bonamente, E.; Brigida, M.

2010-01-01

The gamma-ray energy spectra of bright blazars of the LAT Bright AGN Sample (LBAS) are investigated using Fermi-LAT data. Spectral properties (hardness, curvature, and variability) established using a data set accumulated over 6 months of operation are presented and discussed for different blazar classes and subclasses: flat spectrum radio quasars (FSRQs), low-synchrotron peaked BLLacs (LSP-BLLacs), intermediate-synchrotron peaked BLLacs (ISP-BLLacs), and high-synchrotron peaked BLLacs (HSP-BLLacs). The distribution of photon index (Γ, obtained from a power-law fit above 100 MeV) is found to correlate strongly with blazar subclass. The change in spectral index from that averaged over the 6 months observing period is < 0.2-0.3 when the flux varies by about an order of magnitude, with a tendency toward harder spectra when the flux is brighter for FSRQs and LSP-BLLacs. A strong departure from a single power-law spectrum appears to be a common feature for FSRQs. This feature is also present for some high-luminosity LSP-BLLacs, and a small number of ISP-BLLacs. It is absent in all LBAS HSP-BLLacs. For 3C 454.3 and AO 0235+164, the two brightest FSRQ source and LSP-BLLac source, respectively, a broken power law (BPL) gives the most acceptable of power law, BPL, and curved forms. The consequences of these findings are discussed.

BRIGHTNESS AND FLUCTUATION OF THE MID-INFRARED SKY FROM AKARI OBSERVATIONS TOWARD THE NORTH ECLIPTIC POLE

International Nuclear Information System (INIS)

Pyo, Jeonghyun; Jeong, Woong-Seob; Matsumoto, Toshio; Matsuura, Shuji

2012-01-01

We present the smoothness of the mid-infrared sky from observations by the Japanese infrared astronomical satellite AKARI. AKARI monitored the north ecliptic pole (NEP) during its cold phase with nine wave bands covering from 2.4 to 24 μm, out of which six mid-infrared bands were used in this study. We applied power-spectrum analysis to the images in order to search for the fluctuation of the sky brightness. Observed fluctuation is explained by fluctuation of photon noise, shot noise of faint sources, and Galactic cirrus. The fluctuations at a few arcminutes scales at short mid-infrared wavelengths (7, 9, and 11 μm) are largely caused by the diffuse Galactic light of the interstellar dust cirrus. At long mid-infrared wavelengths (15, 18, and 24 μm), photon noise is the dominant source of fluctuation over the scale from arcseconds to a few arcminutes. The residual fluctuation amplitude at 200'' after removing these contributions is at most 1.04 ± 0.23 nW m –2 sr –1 or 0.05% of the brightness at 24 μm and at least 0.47 ± 0.14 nW m –2 sr –1 or 0.02% at 18 μm. We conclude that the upper limit of the fluctuation in the zodiacal light toward the NEP is 0.03% of the sky brightness, taking 2σ error into account.

Visible Color and Photometry of Bright Materials on Vesta

Science.gov (United States)

Schroder, S. E.; Li, J. Y.; Mittlefehldt, D. W.; Pieters, C. M.; De Sanctis, M. C.; Hiesinger, H.; Blewett, D. T.; Russell, C. T.; Raymond, C. A.; Keller, H. U.

2012-01-01

The Dawn Framing Camera (FC) collected images of the surface of Vesta at a pixel scale of 70 m in the High Altitude Mapping Orbit (HAMO) phase through its clear and seven color filters spanning from 430 nm to 980 nm. The surface of Vesta displays a large diversity in its brightness and colors, evidently related to the diverse geology [1] and mineralogy [2]. Here we report a detailed investigation of the visible colors and photometric properties of the apparently bright materials on Vesta in order to study their origin. The global distribution and the spectroscopy of bright materials are discussed in companion papers [3, 4], and the synthesis results about the origin of Vestan bright materials are reported in [5].

Helmholtz bright and boundary solitons

Energy Technology Data Exchange (ETDEWEB)

Christian, J M [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom); McDonald, G S [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom); Chamorro-Posada, P [Departmento de TeorIa de la Senal y Comunicaciones e IngenierIa Telematica, Universidad de Valladolid, ETSI Telecomunicacion, Campus Miguel Delibes s/n, 47011 Valladolid (Spain)

2007-02-16

We report, for the first time, exact analytical boundary solitons of a generalized cubic-quintic nonlinear Helmholtz (NLH) equation. These solutions have a linked-plateau topology that is distinct from conventional dark soliton solutions; their amplitude and intensity distributions are spatially delocalized and connect regions of finite and zero wave-field disturbances (suggesting also the classification as 'edge solitons'). Extensive numerical simulations compare the stability properties of recently derived Helmholtz bright solitons, for this type of polynomial nonlinearity, to those of the new boundary solitons. The latter are found to possess a remarkable stability characteristic, exhibiting robustness against perturbations that would otherwise lead to the destabilizing of their bright-soliton counterparts.

High Brightness Injectors Based On Photocathode DC Gun

International Nuclear Information System (INIS)

B. Yunn

2001-01-01

Sample results of new injector design method based on a photocathode dc gun are presented, based on other work analytically proving the validity of the emittance compensation scheme for the case even when beam bunching is involved. We have designed several new injectors appropriate for different bunch charge ranges accordingly. Excellent beam quality produced by these injectors clearly shows that a photocathode dc gun can compete with a rf gun on an equal footing as the source of an electron beam for the bunch charge ranging up to 2 nano Coulomb (nC). This work therefore elevates a dc gun based injector to the preferred choice for many ongoing high brightness accelerator projects considering the proven operational stability and high average power capability of the dc gun

Advanced high brightness ion rf accelerator applications in the nuclear energy

International Nuclear Information System (INIS)

Jameson, R.A.

1991-01-01

The capability of modern rf linear accelerators to provide intense high quality beams of protons, deuterons, or heavier ions is opening new possibilities for transmuting existing nuclear wastes, for generating electricity from readily available fuels with minimal residual wastes, for building intense neutron sources for materials research, for inertial confinement fusion using heavy ions, and for other new applications. These are briefly described, couched in a perspective of the advances in the understanding of the high brightness beams that has enabled these new programs. 32 refs., 2 figs

Human CD56bright NK Cells

DEFF Research Database (Denmark)

Michel, Tatiana; Poli, Aurélie; Cuapio, Angelica

2016-01-01

Human NK cells can be subdivided into various subsets based on the relative expression of CD16 and CD56. In particular, CD56(bright)CD16(-/dim) NK cells are the focus of interest. They are considered efficient cytokine producers endowed with immunoregulatory properties, but they can also become c...... NK cell subsets is not fully defined, nor is their precise hematopoietic origin. In this article, we summarize recent studies about CD56(bright) NK cells in health and disease and briefly discuss the current controversies surrounding them....

Music for a Brighter World: Brightness Judgment Bias by Musical Emotion.

Science.gov (United States)

Bhattacharya, Joydeep; Lindsen, Job P

2016-01-01

A prevalent conceptual metaphor is the association of the concepts of good and evil with brightness and darkness, respectively. Music cognition, like metaphor, is possibly embodied, yet no study has addressed the question whether musical emotion can modulate brightness judgment in a metaphor consistent fashion. In three separate experiments, participants judged the brightness of a grey square that was presented after a short excerpt of emotional music. The results of Experiment 1 showed that short musical excerpts are effective emotional primes that cross-modally influence brightness judgment of visual stimuli. Grey squares were consistently judged as brighter after listening to music with a positive valence, as compared to music with a negative valence. The results of Experiment 2 revealed that the bias in brightness judgment does not require an active evaluation of the emotional content of the music. By applying a different experimental procedure in Experiment 3, we showed that this brightness judgment bias is indeed a robust effect. Altogether, our findings demonstrate a powerful role of musical emotion in biasing brightness judgment and that this bias is aligned with the metaphor viewpoint.

Development of a High-Brightness VHF Electron Source at LBNL

International Nuclear Information System (INIS)

Lidia, Steven M.; Sannibale, Fernando; Staples, John W.; Virostek, Steve P.; Wells, Russell P.

2007-01-01

Currently proposed ERL and high average power FEL projects require electron beam sources that can generate ∼1nC bunch charges at high repetition rates. Many proposed sources are based around either high voltage DC or microwave RF guns, each with its particular set of technological limits and system complications. We propose a novel solution that greatly diminishes high voltage breakdown issues while also decreasing peak RF power requirements in a warm copper device, and that has the benefit of mapping the rf oscillation period much more closely to the required beam repetition rate. We present the initial RF and mechanical design for a 750kV electron source and beam injection system utilizing a gun resonant in the VHF band. Beam dynamics simulations demonstrate excellent beam quality preservation and transport

Hybrid white organic light emitting diodes with low efficiency roll-off, stable color and extreme brightness

Energy Technology Data Exchange (ETDEWEB)

Liu, Baiquan; Zou, Jianhua [Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640 (China); State Key Laboratory of Luminescent Materials and Devices, Guangzhou 510640 (China); Su, Yueju; Gao, Dongyu [New Vision Opto-Electronic Technology Co., Ltd, Guangzhou 510640 (China); Lan, Linfeng [Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640 (China); State Key Laboratory of Luminescent Materials and Devices, Guangzhou 510640 (China); Tao, Hong, E-mail: tao.h@scut.edu.cn [Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640 (China); State Key Laboratory of Luminescent Materials and Devices, Guangzhou 510640 (China); Peng, Junbiao [Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640 (China); State Key Laboratory of Luminescent Materials and Devices, Guangzhou 510640 (China)

2014-07-01

Highly efficient and bright hybrid white organic light emitting diodes (WOLEDs) based on simple architectures have been successfully fabricated and characterized. The optimized device can reach a maximum forward-viewing power efficiency (PE) of 20.2 lm/W, a peak forward-viewing current efficiency (CE) of 30.7 cd/A, an extremely high brightness of 95,683 cd/m{sup 2}, and a Commission International de l’E clairage chromaticity coordinates of (0. 436, 0.425) at 12 V. Even at the illumination-relevant brightness of 1000 cd/m{sup 2}, a forward-viewing PE of 17.0 lm/W and CE of 30.7 cd/A are obtained. Moreover, it is found that the device not only suffers slight efficiency roll-off but also exhibits a stable color during a large range of brightness, indicating that the device can satisfy the future commercial requirements. Undoubtedly, the results will be beneficial to the design of both material and device architecture for high-performance WOLEDs and next-generation solid-state lighting sources. - Highlights: • A simple HWOLED with B/O/B structure has been successfully developed. • A extremely high brigthness of 95,683 cd/m{sup 2} is obtained. • A high forward-viewing CE of 30.7 cd/A and PE of 20.2 lm/W are achieved. • Efficiency roll-off is very low and color is relatively stable.

Simultaneous brightness contrast of foraging Papilio butterflies

Science.gov (United States)

Kinoshita, Michiyo; Takahashi, Yuki; Arikawa, Kentaro

2012-01-01

This study focuses on the sense of brightness in the foraging Japanese yellow swallowtail butterfly, Papilio xuthus. We presented two red discs of different intensity on a grey background to butterflies, and trained them to select one of the discs. They were successfully trained to select either a high intensity or a low intensity disc. The trained butterflies were tested on their ability to perceive brightness in two different protocols: (i) two orange discs of different intensity presented on the same intensity grey background and (ii) two orange discs of the same intensity separately presented on a grey background that was either higher or lower in intensity than the training background. The butterflies trained to high intensity red selected the orange disc of high intensity in protocol 1, and the disc on the background of low intensity grey in protocol 2. We obtained similar results in another set of experiments with purple discs instead of orange discs. The choices of the butterflies trained to low intensity red were opposite to those just described. Taken together, we conclude that Papilio has the ability to learn brightness and darkness of targets independent of colour, and that they have the so-called simultaneous brightness contrast. PMID:22179808

Low surface brightness galaxies in the Fornax Cluster: automated galaxy surface photometry

International Nuclear Information System (INIS)

Davies, J.I.; Phillipps, S.; Disney, M.J.

1988-01-01

A sample is presented of low surface brightness galaxies (with extrapolated central surface brightness fainter than 22.0 Bμ) in the Fornax Cluster region which has been measured by the APM machine. Photometric parameters, namely profile shape, scale length, central brightness and total magnitude, are derived for the sample galaxies and correlations between the parameters of low surface brightness dwarf galaxies are discussed, with particular reference to the selection limits. Contrary to previous authors we find no evidence for a luminosity-surface brightness correlation in the sense of lower surface brightness galaxies having lower luminosities and scale sizes. In fact, the present data suggest that it is the galaxies with the largest scale lengths which are more likely to be of very low surface brightness. In addition, the larger scale length galaxies occur preferentially towards the centre of the Cluster. (author)

Error sources in the retrieval of aerosol information over bright surfaces from satellite measurements in the oxygen A band

Science.gov (United States)

Nanda, Swadhin; de Graaf, Martin; Sneep, Maarten; de Haan, Johan F.; Stammes, Piet; Sanders, Abram F. J.; Tuinder, Olaf; Pepijn Veefkind, J.; Levelt, Pieternel F.

2018-01-01

Retrieving aerosol optical thickness and aerosol layer height over a bright surface from measured top-of-atmosphere reflectance spectrum in the oxygen A band is known to be challenging, often resulting in large errors. In certain atmospheric conditions and viewing geometries, a loss of sensitivity to aerosol optical thickness has been reported in the literature. This loss of sensitivity has been attributed to a phenomenon known as critical surface albedo regime, which is a range of surface albedos for which the top-of-atmosphere reflectance has minimal sensitivity to aerosol optical thickness. This paper extends the concept of critical surface albedo for aerosol layer height retrievals in the oxygen A band, and discusses its implications. The underlying physics are introduced by analysing the top-of-atmosphere reflectance spectrum as a sum of atmospheric path contribution and surface contribution, obtained using a radiative transfer model. Furthermore, error analysis of an aerosol layer height retrieval algorithm is conducted over dark and bright surfaces to show the dependence on surface reflectance. The analysis shows that the derivative with respect to aerosol layer height of the atmospheric path contribution to the top-of-atmosphere reflectance is opposite in sign to that of the surface contribution - an increase in surface brightness results in a decrease in information content. In the case of aerosol optical thickness, these derivatives are anti-correlated, leading to large retrieval errors in high surface albedo regimes. The consequence of this anti-correlation is demonstrated with measured spectra in the oxygen A band from the GOME-2 instrument on board the Metop-A satellite over the 2010 Russian wildfires incident.

Discussion on the source survey method in a natural evaporation pond

International Nuclear Information System (INIS)

Dai Xiaoshu; Fan Chengrong; Fu Yunshan

2014-01-01

A natural evaporation pond intended to be decommissioned. The survey of the pond focused on investigating radioactive contamination distribution and estimating the total amount of deposits in the pond, in order to provide support for subsequent decommissioning activities. Based on the source survey in the pond, this paper introduced how to implement radiation measurements and sampling (such as water and sediment) in the water. The movable work platform was built on the pond to facilitate sampling and measurement. In addition, a sludge sampler had been designed so as to accurately determine the amount of sampling and its depth. This paper also described the distribution of sampling points. (authors)

THE INFRARED PROPERTIES OF SOURCES MATCHED IN THE WISE ALL-SKY AND HERSCHEL ATLAS SURVEYS

Energy Technology Data Exchange (ETDEWEB)

Bond, Nicholas A.; Benford, Dominic J.; Gardner, Jonathan P. [Cosmology Laboratory (Code 665), NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Amblard, Alexandre [Astrophysics Branch, NASA/Ames Research Center, MS 245-6, Moffett Field, CA 94035 (United States); Fleuren, Simone [School of Mathematical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom); Blain, Andrew W. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Dunne, Loretta; Maddox, Steve J.; Hoyos, Carlos; Bourne, Nathan [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Smith, Daniel J. B.; Bonfield, David [Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield, Herts AL10 9AB (United Kingdom); Baes, Maarten [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent (Belgium); Bridge, Carrie [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Buttiglione, Sara; De Zotti, Gianfranco [INAF-Osservatorio Astronomico di Padova, Vicolo Osservatorio 5, I-35122 Padova (Italy); Cava, Antonio [Departamento de Astrofisica, Facultad de CC. Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Clements, David [Imperial College, Astrophysics Group, Blackett Lab, Prince Consort Road, London SW7 2AZ (United Kingdom); Cooray, Asantha [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Dariush, Ali [Physics Department, Imperial College London, South Kensington Campus, SW7 2AZ (United Kingdom); and others

2012-05-01

We describe the infrared properties of sources detected over {approx}36 deg{sup 2} of sky in the GAMA 15 hr equatorial field, using data from both the Herschel Astrophysical Terahertz Large-Area Survey (H-ATLAS) and Wide-field Infrared Survey (WISE). With 5{sigma} point-source depths of 34 and 0.048 mJy at 250 {mu}m and 3.4 {mu}m, respectively, we are able to identify 50.6% of the H-ATLAS sources in the WISE survey, corresponding to a surface density of {approx}630 deg{sup -2}. Approximately two-thirds of these sources have measured spectroscopic or optical/near-IR photometric redshifts of z < 1. For sources with spectroscopic redshifts at z < 0.3, we find a linear correlation between the infrared luminosity at 3.4 {mu}m and that at 250 {mu}m, with {+-}50% scatter over {approx}1.5 orders of magnitude in luminosity, {approx}10{sup 9}-10{sup 10.5} L{sub Sun }. By contrast, the matched sources without previously measured redshifts (r {approx}> 20.5) have 250-350 {mu}m flux density ratios which suggest either high-redshift galaxies (z {approx}> 1.5) or optically faint low-redshift galaxies with unusually low temperatures (T {approx}< 20). Their small 3.4-250 {mu}m flux ratios favor a high-redshift galaxy population, as only the most actively star-forming galaxies at low redshift (e.g., Arp 220) exhibit comparable flux density ratios. Furthermore, we find a relatively large active galactic nucleus fraction ({approx}30%) in a 12 {mu}m flux-limited subsample of H-ATLAS sources, also consistent with there being a significant population of high-redshift sources in the no-redshift sample.

High-energy Neutrino Flares from X-Ray Bright and Dark Tidal Disruption Events

Energy Technology Data Exchange (ETDEWEB)

Senno, Nicholas; Murase, Kohta; Mészáros, Peter [Department of Physics, The Pennsylvania State University, University Park, PA 16802 (United States)

2017-03-20

X-ray and γ-ray observations by the Swift satellite revealed that a fraction of tidal disruption events (TDEs) have relativistic jets. Jetted TDEs have been considered to be potential sources of very-high-energy cosmic-rays and neutrinos. In this work, using semi-analytical methods, we calculate neutrino spectra of X-ray bright TDEs with powerful jets and dark TDEs with possible choked jets, respectively. We estimate their neutrino fluxes and find that non-detection would give us an upper limit on the baryon loading of the jet luminosity contained in cosmic-rays ξ {sub cr} ≲ 20–50 for Sw J1644+57. We show that X-ray bright TDEs make a sub-dominant (≲5%–10%) contribution to IceCube’s diffuse neutrino flux, and study possible contributions of X-ray dark TDEs given that particles are accelerated in choked jets or disk winds. We discuss future prospects for multi-messenger searches of the brightest TDEs.

EQ-10 electrodeless Z-pinch EUV source for metrology applications

Science.gov (United States)

Gustafson, Deborah; Horne, Stephen F.; Partlow, Matthew J.; Besen, Matthew M.; Smith, Donald K.; Blackborow, Paul A.

2011-11-01

With EUV Lithography systems shipping, the requirements for highly reliable EUV sources for mask inspection and resist outgassing are becoming better defined, and more urgent. The sources needed for metrology applications are very different than that needed for lithography; brightness (not power) is the key requirement. Suppliers for HVM EUV sources have all resources working on high power and have not entered the smaller market for metrology. Energetiq Technology has been shipping the EQ-10 Electrodeless Z-pinchTM light source since 19951. The source is currently being used for metrology, mask inspection, and resist development2-4. These applications require especially stable performance in both output power and plasma size and position. Over the last 6 years Energetiq has made many source modifications which have included better thermal management to increase the brightness and power of the source. We now have introduced a new source that will meet requirements of some of the mask metrology first generation tools; this source will be reviewed.

Quantum Interference between Autonomous Single-Photon Sources from Doppler-Broadened Atomic Ensemble

OpenAIRE

Jeong, Teak; Lee, Yoon-Seok; Park, Jiho; Kim, Heonoh; Moon, Han Seb

2017-01-01

To realize a quantum network based on quantum entanglement swapping, bright and completely autonomous sources are essentially required. Here, we experimentally demonstrate Hong-Ou-Mandel (HOM) quantum interference between two independent bright photon pairs generated via the spontaneous four-wave mixing in Doppler-broadened ladder-type 87Rb atoms. Bright autonomous heralded single photons are operated in a continuous-wave (CW) mode with no synchronization or supplemental filters. The four-fol...

Bright THz Instrument and Nonlinear THz Science

Science.gov (United States)

2017-10-30

Report: Bright THz Instrument and Nonlinear THz Science The views, opinions and/or findings contained in this report are those of the author(s) and...Number: W911NF-16-1-0436 Organization: University of Rochester Title: Bright THz Instrument and Nonlinear THz Science Report Term: 0-Other Email: xi...exploring new cutting-edge research and broader applications, following the significant development of THz science and technology in the late 80’s, is the

Micro Coronal Bright Points Observed in the Quiet Magnetic Network by SOHO/EIT

Science.gov (United States)

Falconer, D. A.; Moore, R. L.; Porter, J. G.

1997-01-01

When one looks at SOHO/EIT Fe XII images of quiet regions, one can see the conventional coronal bright points (> 10 arcsec in diameter), but one will also notice many smaller faint enhancements in brightness (Figure 1). Do these micro coronal bright points belong to the same family as the conventional bright points? To investigate this question we compared SOHO/EIT Fe XII images with Kitt Peak magnetograms to determine whether the micro bright points are in the magnetic network and mark magnetic bipoles within the network. To identify the coronal bright points, we applied a picture frame filter to the Fe XII images; this brings out the Fe XII network and bright points (Figure 2) and allows us to study the bright points down to the resolution limit of the SOHO/EIT instrument. This picture frame filter is a square smoothing function (hlargelyalf a network cell wide) with a central square (quarter of a network cell wide) removed so that a bright point's intensity does not effect its own background. This smoothing function is applied to the full disk image. Then we divide the original image by the smoothed image to obtain our filtered image. A bright point is defined as any contiguous set of pixels (including diagonally) which have enhancements of 30% or more above the background; a micro bright point is any bright point 16 pixels or smaller in size. We then analyzed the bright points that were fully within quiet regions (0.6 x 0.6 solar radius) centered on disk center on six different days.

Diagnosing the doctors' departure: survey on sources of dissatisfaction among Irish junior doctors.

LENUS (Irish Health Repository)

Bruce-Brand, R

2012-01-01

There has been a significant decline in the number of applications for non-consultant hospital doctor (NCHD) posts in Ireland over the last 18 months. We conducted an online, anonymous survey of Irish NCHDs to establish levels of satisfaction, sources of dissatisfaction and the major reasons for junior doctors seeking work abroad. 522 NCHDs took the survey, including 64 (12.3%) currently working outside of the Republic. 219 (45.8%) were slightly dissatisfied and 142 (29.7%) were extremely dissatisfied with practising medicine in Ireland. Major sources of dissatisfaction included the state of the health care system, staffing cover for leave and illness, the dearth of consultant posts and the need to move around Ireland. The most important reason for NCHDs wishing to leave was to seek better training and career opportunities abroad.

Music for a Brighter World: Brightness Judgment Bias by Musical Emotion.

Directory of Open Access Journals (Sweden)

Joydeep Bhattacharya

Full Text Available A prevalent conceptual metaphor is the association of the concepts of good and evil with brightness and darkness, respectively. Music cognition, like metaphor, is possibly embodied, yet no study has addressed the question whether musical emotion can modulate brightness judgment in a metaphor consistent fashion. In three separate experiments, participants judged the brightness of a grey square that was presented after a short excerpt of emotional music. The results of Experiment 1 showed that short musical excerpts are effective emotional primes that cross-modally influence brightness judgment of visual stimuli. Grey squares were consistently judged as brighter after listening to music with a positive valence, as compared to music with a negative valence. The results of Experiment 2 revealed that the bias in brightness judgment does not require an active evaluation of the emotional content of the music. By applying a different experimental procedure in Experiment 3, we showed that this brightness judgment bias is indeed a robust effect. Altogether, our findings demonstrate a powerful role of musical emotion in biasing brightness judgment and that this bias is aligned with the metaphor viewpoint.

Richard Bright and his neurological studies.

Science.gov (United States)

Pearce, J M S

2009-01-01

Richard Bright was one of the famous triumvirate of Guy's Hospital physicians in the Victorian era. Remembered for his account of glomerulonephritis (Bright's disease) he also made many important and original contributions to medicine and neurology. These included his work on cortical epileptogenesis, descriptions of simple partial (Jacksonian) seizures, infantile convulsions, and a variety of nervous diseases. Most notable were his reports of neurological studies including papers on traumatic tetanus, syringomyelia, arteries of the brain, contractures of spinal origin, tumours of the base of the brain, and narcolepsy. His career and these contributions are outlined. Copyright 2009 S. Karger AG, Basel.

Sky brightness and twilight measurements at Jogyakarta city, Indonesia

International Nuclear Information System (INIS)

Herdiwijaya, Dhani

2016-01-01

The sky brightness measurements were performed using a portable photometer. A pocket-sized and low-cost photometer has 20 degree area measurement, and spectral ranges between 320-720 nm with output directly in magnitudes per arc second square (mass) unit. The sky brightness with 3 seconds temporal resolutions was recorded at Jogyakarta city (110° 25’ E; 70° 52’ S; elevation 100 m) within 136 days in years from 2014 to 2016. The darkest night could reach 22.61 mpass only in several seconds, with mean value 18.8±0.7 mpass and temperature variation 23.1±1.2 C. The difference of mean sky brightness between before and after midnight was about -0.76 mpass or 2.0 times brighter. Moreover, the sky brightness and temperature fluctuations were more stable in after midnight than in before midnight. It is suggested that city light pollution affects those variations, and subsequently duration of twilight. By comparing twilight brightness for several places, we also suggest a 17° solar dip or about 66 minutes before sunrise for new time of Fajr prayer. (paper)

Generation of a high-brightness pulsed positron beam for the Munich scanning positron microscope

Energy Technology Data Exchange (ETDEWEB)

Piochacz, Christian

2009-11-20

Within the present work the prerequisites for the operation of the Munich scanning positron microscope (SPM) at the high intense neutron induced positron source Munich (NEPOMUC) were established. This was accomplished in two steps: Firstly, a re-moderation device was installed at the positron beam facility NEPOMUC, which enhances the brightness of the positron beam for all connected experiments. The second step was the design, set up and initial operation of the SPM interface for the high efficient conversion of the continuous beam into a bunched beam. The in-pile positron source NEPOMUC creates a positron beam with a diameter of typically 7 mm, a kinetic energy of 1 keV and an energy spread of 50 eV. The NEPOMUC re-moderator generates from this beam a low energy positron beam (20 - 200 eV) with a diameter of less than 2 mm and an energy spread well below 2.5 eV. This was achieved with an excellent total efficiency of 6.55{+-}0.25 %. The re-moderator was not only the rst step to implement the SPM at NEPOMUc, it enables also the operation of the pulsed low energy positron beam system (PLEPS). Within the present work, at this spectrometer rst positron lifetime measurements were performed, which revealed the defect types of an ion irradiated uranium molybdenum alloy. Moreover, the instruments which were already connected to the positron beam facility bene ts considerably of the high brightness enhancement. In the new SPM interface an additional re-moderation stage enhances the brightness of the beam even more and will enable positron lifetime measurements at the SPM with a lateral resolution below 1 {mu}m. The efficiency of the re-moderation process in this second stage was 24.5{+-}4.5 %. In order to convert high efficiently the continuous positron beam into a pulsed beam with a repetition rate of 50 MHz and a pulse duration of less than 50 ps, a sub-harmonic pre-bucher was combined with two sine wave bunchers. Furthermore, the additional re-moderation stage of the

Generation of a high-brightness pulsed positron beam for the Munich scanning positron microscope

International Nuclear Information System (INIS)

Piochacz, Christian

2009-01-01

Within the present work the prerequisites for the operation of the Munich scanning positron microscope (SPM) at the high intense neutron induced positron source Munich (NEPOMUC) were established. This was accomplished in two steps: Firstly, a re-moderation device was installed at the positron beam facility NEPOMUC, which enhances the brightness of the positron beam for all connected experiments. The second step was the design, set up and initial operation of the SPM interface for the high efficient conversion of the continuous beam into a bunched beam. The in-pile positron source NEPOMUC creates a positron beam with a diameter of typically 7 mm, a kinetic energy of 1 keV and an energy spread of 50 eV. The NEPOMUC re-moderator generates from this beam a low energy positron beam (20 - 200 eV) with a diameter of less than 2 mm and an energy spread well below 2.5 eV. This was achieved with an excellent total efficiency of 6.55±0.25 %. The re-moderator was not only the rst step to implement the SPM at NEPOMUc, it enables also the operation of the pulsed low energy positron beam system (PLEPS). Within the present work, at this spectrometer rst positron lifetime measurements were performed, which revealed the defect types of an ion irradiated uranium molybdenum alloy. Moreover, the instruments which were already connected to the positron beam facility bene ts considerably of the high brightness enhancement. In the new SPM interface an additional re-moderation stage enhances the brightness of the beam even more and will enable positron lifetime measurements at the SPM with a lateral resolution below 1 μm. The efficiency of the re-moderation process in this second stage was 24.5±4.5 %. In order to convert high efficiently the continuous positron beam into a pulsed beam with a repetition rate of 50 MHz and a pulse duration of less than 50 ps, a sub-harmonic pre-bucher was combined with two sine wave bunchers. Furthermore, the additional re-moderation stage of the SPM

Getting to the Source: a Survey of Quantitative Data Sources Available to the Everyday Librarian: Part II: Data Sources from Specific Library Applications

Directory of Open Access Journals (Sweden)

Lisa Goddard

2007-03-01

Full Text Available This is the second part of a two-part article that provides a survey of data sources which are likely to be immediately available to the typical practitioner who wishes to engage in statistical analysis of collections and services within his or her own library. Part I outlines the data elements which can be extracted from web server logs, and discusses web log analysis tools. Part II looks at logs, reports, and data sources from proxy servers, resource vendors, link resolvers, federated search engines, institutional repositories, electronic reference services, and the integrated library system.

Update on the KELT Transit Survey: Hot Planets around Hot Stars

Science.gov (United States)

Gaudi, B. Scott; Stassun, Keivan G.; Pepper, Joshua; KELT Collaboration

2018-01-01

The KELT Transit Survey consists of a pair of small-aperture, wide-angle automated telescopes located at Winer Observatory in Sonoita, Arizona and the South African Astronomical Observatory (SAAO) in Sutherland, South Africa. Together, they are surveying roughly 70% of the sky for transiting planets. By virtue of their small apertures (42 mm) and large fields-of-view (26 degrees x 26 degrees), KELT is most sensitive to hot Jupiters transiting relatively bright (V~8-11), and thus relatively hot stars. I will provide an update on the planets discovered by KELT, focusing in detail on our recent discoveries of very hot planets transiting several bright A and early F stars.

The Los Alamos high-brightness photoinjector

Energy Technology Data Exchange (ETDEWEB)

O' Shea, P.G.

1991-01-01

For a number of years Los Alamos National Laboratory has been developing photocathode RF guns for high-brightness electron beam applications such as free-electron lasers (FELs). Previously thermionic high-voltage guns have been the source of choice for the electron accelerators used to drive FELs. The performance of such FELs is severely limited by the emittance growth produced by the subharmonic bunching process and also by the low peak current of the source. In a photoinjector, a laser driven photocathode is placed directly in a high-gradient RF accelerating cavity. A photocathode allows unsurpassed control over the current, and the spatial and temporal profile of the beam. In addition the electrodeless emission'' avoids many of the difficulties associated with multi-electrode guns, i.e. the electrons are accelerated very rapidly to relativistic energies, and there are no electrodes to distort the accelerating fields. For the past two years we have been integrating a photocathode into our existing FEL facility by replacing our thermionic gun and subharmonic bunchers with a high-gradient 1.3 GHz photoinjector. The photoinjector, which is approximately 0.6 m in length, produces 6 MeV, 300 A, 15 ps linac, and accelerated to a final energy of 40 MeV. We have recently begun lasing at wavelengths near 3 {mu}m. 16 refs., 2 figs., 5 tabs.

Deep 20-GHz survey of the Chandra Deep Field South and SDSS Stripe 82: source catalogue and spectral properties

Science.gov (United States)

Franzen, Thomas M. O.; Sadler, Elaine M.; Chhetri, Rajan; Ekers, Ronald D.; Mahony, Elizabeth K.; Murphy, Tara; Norris, Ray P.; Waldram, Elizabeth M.; Whittam, Imogen H.

2014-04-01

We present a source catalogue and first results from a deep, blind radio survey carried out at 20 GHz with the Australia Telescope Compact Array, with follow-up observations at 5.5, 9 and 18 GHz. The Australia Telescope 20 GHz (AT20G) deep pilot survey covers a total area of 5 deg2 in the Chandra Deep Field South and in Stripe 82 of the Sloan Digital Sky Survey. We estimate the survey to be 90 per cent complete above 2.5 mJy. Of the 85 sources detected, 55 per cent have steep spectra (α _{1.4}^{20} law spectra between 1.4 and 18 GHz, while the spectral indices of the flat- or inverted-spectrum sources tend to steepen with frequency. Among the 18 inverted-spectrum (α _{1.4}^{20} ≥ 0.0) sources, 10 have clearly defined peaks in their spectra with α _{1.4}^{5.5} > 0.15 and α 9^{18} Cambridge and Tenth Cambridge surveys: there is a shift towards a steeper-spectrum population when going from ˜1 Jy to ˜5 mJy, which is followed by a shift back towards a flatter-spectrum population below ˜5 mJy. The 5-GHz source-count model by Jackson & Wall, which only includes contributions from FRI and FRII sources, and star-forming galaxies, does not reproduce the observed flattening of the flat-spectrum counts below ˜5 mJy. It is therefore possible that another population of sources is contributing to this effect.

Relationship of magnetic field strength and brightness of fine-structure elements in the solar temperature minimum region

Science.gov (United States)

Cook, J. W.; Ewing, J. A.

1990-01-01

A quantitative relationship was determined between magnetic field strength (or magnetic flux) from photospheric magnetograph observations and the brightness temperature of solar fine-structure elements observed at 1600 A, where the predominant flux source is continuum emission from the solar temperature minimum region. A Kitt Peak magnetogram and spectroheliograph observations at 1600 A taken during a sounding rocket flight of the High Resolution Telescope and Spectrograph from December 11, 1987 were used. The statistical distributions of brightness temperature in the quiet sun at 1600 A, and absolute value of magnetic field strength in the same area were determined from these observations. Using a technique which obtains the best-fit relationship of a given functional form between these two histogram distributions, a quantitative relationship was determined between absolute value of magnetic field strength B and brightness temperature which is essentially linear from 10 to 150 G. An interpretation is suggested, in which a basal heating occurs generally, while brighter elements are produced in magnetic regions with temperature enhancements proportional to B.

THE NEXT GENERATION VIRGO CLUSTER SURVEY (NGVS). I. INTRODUCTION TO THE SURVEY

International Nuclear Information System (INIS)

Ferrarese, Laura; Côté, Patrick; Gwyn, S. D. J.; MacArthur, Lauren A.; McConnachie, Alan W.; Blakeslee, John P.; Cuillandre, Jean-Charles; Peng, Eric W.; Duc, Pierre-Alain; Boselli, A.; Mei, Simona; Erben, Thomas; Durrell, Patrick R.; Christopher Mihos, J.; Jordán, Andrés; Puzia, Thomas H.; Lançon, Ariane; Emsellem, Eric; Balogh, Michael L.; Van Waerbeke, Ludovic

2012-01-01

The Next Generation Virgo Cluster Survey (NGVS) is a program that uses the 1 deg 2 MegaCam instrument on the Canada-France-Hawaii Telescope to carry out a comprehensive optical imaging survey of the Virgo cluster, from its core to its virial radius—covering a total area of 104 deg 2 —in the u*griz bandpasses. Thanks to a dedicated data acquisition strategy and processing pipeline, the NGVS reaches a point-source depth of g ≈ 25.9 mag (10σ) and a surface brightness limit of μ g ∼ 29 mag arcsec –2 (2σ above the mean sky level), thus superseding all previous optical studies of this benchmark galaxy cluster. In this paper, we give an overview of the technical aspects of the survey, such as areal coverage, field placement, choice of filters, limiting magnitudes, observing strategies, data processing and calibration pipelines, survey timeline, and data products. We also describe the primary scientific topics of the NGVS, which include: the galaxy luminosity and mass functions; the color-magnitude relation; galaxy scaling relations; compact stellar systems; galactic nuclei; the extragalactic distance scale; the large-scale environment of the cluster and its relationship to the Local Supercluster; diffuse light and the intracluster medium; galaxy interactions and evolutionary processes; and extragalactic star clusters. In addition, we describe a number of ancillary programs dealing with 'foreground' and 'background' science topics, including the study of high-inclination trans-Neptunian objects; the structure of the Galactic halo in the direction of the Virgo Overdensity and Sagittarius Stream; the measurement of cosmic shear, galaxy-galaxy, and cluster lensing; and the identification of distant galaxy clusters, and strong-lensing events.

High brightness single photon sources based on photonic wires

DEFF Research Database (Denmark)

Claudon, J.; Bleuse, J.; Bazin, M.

2009-01-01

We present a novel single-photon-source based on the emission of a semiconductor quantum dot embedded in a single-mode photonic wire. This geometry ensures a very large coupling (> 95%) of the spontaneous emission to the guided mode. Numerical simulations show that a photon collection efficiency...

A New Sky Brightness Monitor

Science.gov (United States)

Crawford, David L.; McKenna, D.

2006-12-01

A good estimate of sky brightness and its variations throughout the night, the months, and even the years is an essential bit of knowledge both for good observing and especially as a tool in efforts to minimize sky brightness through local action. Hence a stable and accurate monitor can be a valuable and necessary tool. We have developed such a monitor, with the financial help of Vatican Observatory and Walker Management. The device is now undergoing its Beta test in preparation for production. It is simple, accurate, well calibrated, and automatic, sending its data directly to IDA over the internet via E-mail . Approximately 50 such monitors will be ready soon for deployment worldwide including most major observatories. Those interested in having one should enquire of IDA about details.

AzTEC on ASTE Survey of Submillimeter Galaxies

Science.gov (United States)

Kohno, K.; Tamura, Y.; Hatsukade, B.; Nakanishi, K.; Iono, D.; Takata, T.; Wilson, G. W.; Yun, M. S.; Perera, T.; Austermann, J. E.; Scott, K. S.; Hughes, H.; Aretxaga, I.; Tanaka, K.; Oshima, T.; Yamaguchi, N.; Matsuo, H.; Ezawa, H.; Kawabe, R.

2008-10-01

We have conducted an unprecedented survey of submillimeter galaxies (SMGs) using the 144 pixel bolometer camera AzTEC mounted on the ASTE 10-m dish in Chile. We have already obtained many (>20) wide (typically 12' × 12' or wider) and deep (1 σ sensitivity of 0.5-1.0 mJy) 1.1 mm continuum images of known blank fields and over-density regions/protoclusters across a wide range of redshifts with a spatial resolution of ˜ 30''. It has resulted in the numerous (˜ a few 100, almost equivalent to the total number of the previously known SMGs) new and secure detections of SMGs. In this paper, we present initial results of two selected fields, SSA 22 and AKARI Deep Field South (ADF-S). A significnat clustering of bright SMGs toward the density peak of LAEs is found in SSA 22. We derived the differential and cumulative number counts from the detected sources in ADF-S, which probe the faintest flux densities (down to ˜1 mJy) among 1-mm blank field surveys to date.

GASS: THE PARKES GALACTIC ALL-SKY SURVEY. I. SURVEY DESCRIPTION, GOALS, AND INITIAL DATA RELEASE

International Nuclear Information System (INIS)

McClure-Griffiths, N. M.; Calabretta, M. R.; Ford, H. Alyson; Newton-McGee, K.

2009-01-01

The Parkes Galactic All-Sky Survey (GASS) is a survey of Galactic atomic hydrogen (H I) emission in the Southern sky covering declinations δ ≤ 1 0 using the Parkes Radio Telescope. The survey covers 2π steradians with an effective angular resolution of ∼16', at a velocity resolution of 1.0 km s -1 , and with an rms brightness temperature noise of 57 mK. GASS is the most sensitive, highest angular resolution survey of Galactic H I emission ever made in the Southern sky. In this paper, we outline the survey goals, describe the observations and data analysis, and present the first-stage data release. The data product is a single cube at full resolution, not corrected for stray radiation. Spectra from the survey and other data products are publicly available online.

MOIRCS DEEP SURVEY. V. A UNIVERSAL RELATION FOR STELLAR MASS AND SURFACE BRIGHTNESS OF GALAXIES

International Nuclear Information System (INIS)

Ichikawa, Takashi; Kajisawa, Masaru; Yamada, Toru; Akiyama, Masayuki; Yoshikawa, Tomohiro; Onodera, Masato; Konishi, Masahiro

2010-01-01

We present a universal linear correlation between the stellar mass and surface brightness (SB) of galaxies at 0.3 -2.0∼-0.8 , in addition to dimming as (1 + z) 4 by the cosmological expansion effect. The brightening depends on galaxy color and stellar mass. The blue population (rest-frame U - V -0.8±0.3 in the rest-V band. On the other hand, the red population (U - V>0) and the massive galaxies (M * >10 10 M sun ) show stronger brightening, (1 + z) -1.5±0.1 . By comparison with galaxy evolution models, the phenomena are well understood by the pure luminosity evolution of galaxies out to z ∼ 3.

Measuring brightness temperature distributions of plasma bunches

International Nuclear Information System (INIS)

Kirko, V.I.; Stadnichenko, I.A.

1981-01-01

The possibility of restoration of brightness temperature distribution along plasma jet on the base of a simple ultra high- speed photography and subsequent photometric treatment is shown. The developed technique has been applied for finding spectral radiation intensity and brightness temperature of plasma jets of a tubular gas-cumulative charge and explosive plasma compressor. The problem of shock wave front has been successfully solved and thus distribution of above parameters beginning from the region preceeding the shock wave has been obtained [ru

Conceptual design of a bright electron injector based on a laser-driven photocathode rf electron gun

International Nuclear Information System (INIS)

Chattopadhyay, S.; Chen, Y.J.; Hopkins, D.; Kim, K.J.; Kung, A.; Miller, R.; Sessler, A.; Young, T.

1988-09-01

Conceptual design of a bright electron injector for the 1 GeV high gradient test experiment, envisaged by the LLNL-SLAC-LBL collaboration on the Relativistic Klystron is presented. The design utilizes a high-brightness laser-driven rf photocathode electron gun, similar to the pioneering LANL early studies in concept (different parametrically however), together with achromatic magnetic bunching and transport systems and diagnostics. The design is performed with attention to possible use in an FEL as well. A simple but realistic analytic model including longitudinal and transverse space-charge and rf effects and extensive computer simulation form the basis of the parametric choice for the source. These parameters are used as guides for the design of the picosecond laser system and magnetic bunching section. 4 refs., 5 figs., 2 tabs

Edge integration and the perception of brightness and darkness

NARCIS (Netherlands)

Vladusich, T.; Lucassen, M.P.; Cornelissen, F.W.

2006-01-01

How do induced brightness and darkness signals from local and remote surfaces interact to determine the final achromatic color percept of a target surface? An emerging theory of achromatic color perception posits that brightness and darkness percepts are computed by weighting and summing the

High Brightness OLED Lighting

Energy Technology Data Exchange (ETDEWEB)

Spindler, Jeffrey [OLEDWorks LLC; Kondakova, Marina [OLEDWorks LLC; Boroson, Michael [OLEDWorks LLC; Hamer, John [OLEDWorks LLC

2016-05-25

In this work we describe the technology developments behind our current and future generations of high brightness OLED lighting panels. We have developed white and amber OLEDs with excellent performance based on the stacking approach. Current products achieve 40-60 lm/W, while future developments focus on achieving 80 lm/W or higher.

STARS4ALL Night Sky Brightness Photometer

Directory of Open Access Journals (Sweden)

Jaime Zamorano

2017-06-01

Full Text Available We present the main features of TESS-W, the first version of a series of inexpensive but reliable photometers that will be used to measure night sky brightness. The bandpass is extended to the red with respect of that of the Sky Quality Meter (SQM. TESS-W connects to a router via WIFI and it sends automatically the brightness values to a data repository using Internet of Things protocols. The device includes an infrared sensor to estimate the cloud coverage. It is designed for fixed stations to monitor the evolution of the sky brightness. The photometer could also be used in local mode connected to a computer or tablet to gather data from a moving vehicle. The photometer is being developed within STARS4ALL project, a collective awareness platform for promoting dark skies in Europe, funded by the EU. We intend to extend the existing professional networks to a citizen-based network of photometers. 

Measuring our Universe from Galaxy Redshift Surveys.

Science.gov (United States)

Lahav, Ofer; Suto, Yasushi

2004-01-01

Galaxy redshift surveys have achieved significant progress over the last couple of decades. Those surveys tell us in the most straightforward way what our local Universe looks like. While the galaxy distribution traces the bright side of the Universe, detailed quantitative analyses of the data have even revealed the dark side of the Universe dominated by non-baryonic dark matter as well as more mysterious dark energy (or Einstein's cosmological constant). We describe several methodologies of using galaxy redshift surveys as cosmological probes, and then summarize the recent results from the existing surveys. Finally we present our views on the future of redshift surveys in the era of precision cosmology.

Bright environments vision of the Intelligent Lighting Institute (ILI)

NARCIS (Netherlands)

Özçelebi, T.

2014-01-01

The Bright Environments research program of the Eindhoven University of Technology Intelligent Lighting Institute aims to find new methods of intelligent lighting control and human interaction. We present a summary of the institute’s work on this research field and the research vision of the Bright

Galaxy Size Evolution at High Redshift and Surface Brightness Selection Effects: Constraints from the Hubble Ultra Deep Field

Science.gov (United States)

Bouwens, R. J.; Illingworth, G. D.; Blakeslee, J. P.; Broadhurst, T. J.; Franx, M.

2004-08-01

We use the exceptional depth of the Ultra Deep Field (UDF) and UDF-parallel Advanced Camera for Surveys fields to study the sizes of high-redshift (z~2-6) galaxies and address long-standing questions about possible biases in the cosmic star formation rate due to surface brightness dimming. Contrasting B-, V-, and i-dropout samples culled from the deeper data with those obtained from the shallower Great Observatories Origins Deep Survey fields, we demonstrate that the shallower data are essentially complete at bright magnitudes to z~0.4", >~3 kpc) low surface brightness galaxies are rare. A simple comparison of the half-light radii of the Hubble Deep Field-North + Hubble Deep Field-South U-dropouts with B-, V-, and i-dropouts from the UDF shows that the sizes follow a (1+z)-1.05+/-0.21 scaling toward high redshift. A more rigorous measurement compares different scalings of our U-dropout sample with the mean profiles for a set of intermediate-magnitude (26.0dropouts from the UDF. The best fit is found with a (1+z)-0.94+0.19-0.25 size scaling (for fixed luminosity). This result is then verified by repeating this experiment with different size measures, low-redshift samples, and magnitude ranges. Very similar scalings are found for all comparisons. A robust measurement of size evolution is thereby demonstrated for galaxies from z~6 to 2.5 using data from the UDF. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

Dynamics of bright-bright solitons in Bose-Einstein condensate with Raman-induced one-dimensional spin-orbit coupling

Science.gov (United States)

Wen, Lin; Zhang, Xiao-Fei; Hu, Ai-Yuan; Zhou, Jing; Yu, Peng; Xia, Lei; Sun, Qing; Ji, An-Chun

2018-03-01

We investigate the dynamics of bright-bright solitons in one-dimensional two-component Bose-Einstein condensates with Raman-induced spin-orbit coupling, via the variational approximation and the numerical simulation of Gross-Pitaevskii equations. For the uniform system without trapping potential, we obtain two population balanced stationary solitons. By performing the linear stability analysis, we find a Goldstone eigenmode and an oscillation eigenmode around these stationary solitons. Moreover, we derive a general dynamical solution to describe the center-of-mass motion and spin evolution of the solitons under the action of spin-orbit coupling. The effects of a harmonic trap have also been discussed.

Recalculating the quasar luminosity function of the extended Baryon Oscillation Spectroscopic Survey

Science.gov (United States)

Caditz, David M.

2017-12-01

Aims: The extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey provides a uniform sample of over 13 000 variability selected quasi-stellar objects (QSOs) in the redshift range 0.68 based on this survey may be in error because the k-correction has apparently been misapplied, which results in underestimating the intrinsic brightness of roughly half of the eBOSS sources. This work provides new estimates of the QLF based on a corrected eBOSS dataset. Methods: Intrinsic luminosities were recalculated using the appropriate g-band k-correction function. The QLF was determined for the corrected dataset using a model-weighted estimator, and parametric models were refit to the corrected luminosity function. Projected number counts based on the corrected models are also provided. Results: At redshifts higher than the "pivot" redshift, zp = 2.2, the original and recalculated results differ significantly; in particular, the new results show stronger high-redshift evolution in the best-fit models than the original eBOSS analysis. A new seven-parameter QLF model is provided that fits the corrected eBOSS dataset.

PG 1553 + 11 - A bright optically selected BL Lacertae object

International Nuclear Information System (INIS)

Falomo, R.; Treves, A.

1990-01-01

A detailed study of the bright optically selected BL Lac object PG 1553 + 11 is presented. UV observations, obtained during a high state of the source, together with simultaneous optical spectrophotometry and near-IR photometry, allow the spectral flux distribution to be examined from 8 x 10 to the 13th to 2.5 x 10 to the 15th Hz. This distribution is compared with that derived from quasi-simultaneous observations obtained when the source was a factor of about 3 fainter. It is found that, in the higher state, the spectrum can be described by two power laws connected by a break at about 10 to the 15th Hz, while in the low state the shape is more complex. The overall spectrum of the object is compared with the average energy distribution of X-ray and radio-selected BL Lac objects, showing that it is closer to the former class. 25 refs

Phase advancing human circadian rhythms with morning bright light, afternoon melatonin, and gradually shifted sleep: can we reduce morning bright-light duration?

Science.gov (United States)

Crowley, Stephanie J; Eastman, Charmane I

2015-02-01

Efficient treatments to phase-advance human circadian rhythms are needed to attenuate circadian misalignment and the associated negative health outcomes that accompany early-morning shift work, early school start times, jet lag, and delayed sleep phase disorder. This study compared three morning bright-light exposure patterns from a single light box (to mimic home treatment) in combination with afternoon melatonin. Fifty adults (27 males) aged 25.9 ± 5.1 years participated. Sleep/dark was advanced 1 h/day for three treatment days. Participants took 0.5 mg of melatonin 5 h before the baseline bedtime on treatment day 1, and an hour earlier each treatment day. They were exposed to one of three bright-light (~5000 lux) patterns upon waking each morning: four 30-min exposures separated by 30 min of room light (2-h group), four 15-min exposures separated by 45 min of room light (1-h group), and one 30-min exposure (0.5-h group). Dim-light melatonin onsets (DLMOs) before and after treatment determined the phase advance. Compared to the 2-h group (phase shift = 2.4 ± 0.8 h), smaller phase-advance shifts were seen in the 1-h (1.7 ± 0.7 h) and 0.5-h (1.8 ± 0.8 h) groups. The 2-h pattern produced the largest phase advance; however, the single 30-min bright-light exposure was as effective as 1 h of bright light spread over 3.25 h, and it produced 75% of the phase shift observed with 2 h of bright light. A 30-min morning bright-light exposure with afternoon melatonin is an efficient treatment to phase-advance human circadian rhythms. Copyright © 2014 Elsevier B.V. All rights reserved.

Phase advancing human circadian rhythms with morning bright light, afternoon melatonin, and gradually shifted sleep: can we reduce morning bright light duration?

Science.gov (United States)

Crowley, Stephanie J.; Eastman, Charmane I.

2015-01-01

OBJECTIVE Efficient treatments to phase advance human circadian rhythms are needed to attenuate circadian misalignment and the associated negative health outcomes that accompany early morning shift work, early school start times, jet lag, and delayed sleep phase disorder. This study compared three morning bright light exposure patterns from a single light box (to mimic home treatment) in combination with afternoon melatonin. METHODS Fifty adults (27 males) aged 25.9±5.1 years participated. Sleep/dark was advanced 1 hour/day for 3 treatment days. Participants took 0.5 mg melatonin 5 hours before baseline bedtime on treatment day 1, and an hour earlier each treatment day. They were exposed to one of three bright light (~5000 lux) patterns upon waking each morning: four 30-minute exposures separated by 30 minutes of room light (2 h group); four 15-minute exposures separated by 45 minutes of room light (1 h group), and one 30-minute exposure (0.5 h group). Dim light melatonin onsets (DLMOs) before and after treatment determined the phase advance. RESULTS Compared to the 2 h group (phase shift=2.4±0.8 h), smaller phase advance shifts were seen in the 1 h (1.7±0.7 h) and 0.5 h (1.8±0.8 h) groups. The 2-hour pattern produced the largest phase advance; however, the single 30-minute bright light exposure was as effective as 1 hour of bright light spread over 3.25 h, and produced 75% of the phase shift observed with 2 hours of bright light. CONCLUSIONS A 30-minute morning bright light exposure with afternoon melatonin is an efficient treatment to phase advance human circadian rhythms. PMID:25620199

Measuring and mapping the night sky brightness of Perth, Western Australia

Science.gov (United States)

Biggs, James D.; Fouché, Tiffany; Bilki, Frank; Zadnik, Marjan G.

2012-04-01

In order to study the light pollution produced in the city of Perth, Western Australia, we have used a hand-held sky brightness meter to measure the night sky brightness across the city. The data acquired facilitated the creation of a contour map of night sky brightness across the 2400 km2 area of the city - the first such map to be produced for a city. Importantly, this map was created using a methodology borrowed from the field of geophysics - the well proven and rigorous techniques of geostatistical analysis and modelling. A major finding of this study is the effect of land use on night sky brightness. By overlaying the night sky brightness map on to a suitably processed Landsat satellite image of Perth we found that locations near commercial and/or light industrial areas have a brighter night sky, whereas locations used for agriculture or having high vegetation coverage have a fainter night sky than surrounding areas. Urban areas have intermediate amounts of vegetation and are intermediate in brightness compared with the above-mentioned land uses. Regions with a higher density of major highways also appear to contribute to increased night sky brightness. When corrected for the effects of direct illumination from high buildings, we found that the night sky brightness in the central business district (CBD) is very close to that expected for a city of Perth's population from modelling work and observations obtained in earlier studies. Given that our night sky brightness measurements in Perth over 2009 and 2010 are commensurate with that measured in Canadian cities over 30 years earlier implies that the various lighting systems employed in Perth (and probably most other cities) have not been optimised to minimize light pollution over that time. We also found that night sky brightness diminished with distance with an exponent of approximately -0.25 ± 0.02 from 3.5 to 10 km from the Perth CBD, a region characterized by urban and commercial land use. For distances

Variation reduction of brightness and pH of pulp sent to a paper mill

Directory of Open Access Journals (Sweden)

Napassavong Rojanarowan

2015-03-01

Full Text Available The variance of the brightness of pulp sent to the paper mill during the changing period of dry pulp grades affects the chemical control in the paper mill. This research aims to determine the mixing formula of pulp with different brightness from the EOP and D1 stages to handle this variation issue. This research uses response surface design with Central Composite Design type, regression technique and optimization technique to find the optimal setting of the mixing formula for each of the seven brightness levels to obtain the target brightness of 86% and the pH of 5.25. The mixing formulas are determined by the pulp mixing percentage and the sulfuric acid consumption. The experimental results reveal that when using higher EOP mixing ratio, the brightness decreases and the pH increases. Regarding the effect of the sulfuric acid, increasing the sulfuric acid makes the brightness and the pH decrease. After implementing the optimal formula in the production line, the mean of pulp brightness is closer to the target compared with the brightness before improvement and the brightness variation decreases without affecting the quality of other pulp grades, average of brightness decreased from 87.4% to 86.3% and standard deviation of brightness decreased from 1.09 to 0.46.

Advanced laser technologies for high-brightness photocathode electron gun

International Nuclear Information System (INIS)

Tomizawa, Hiromitsu

2012-01-01

A laser-excited photocathode RF gun is one of the most reliable high-brightness electron beam sources for XFELs. Several 3D laser shaping methods have been developed as ideal photocathode illumination sources at SPring-8 since 2001. To suppress the emittance growth caused by nonlinear space-charge forces, the 3D cylindrical UV-pulse was optimized spatially as a flattop and temporally as squarely stacked chirped pulses. This shaping system is a serial combination of a deformable mirror that adaptively shapes the spatial profile with a genetic algorithm and a UV-pulse stacker that consists of four birefringent α-BBO crystal rods for temporal shaping. Using this 3D-shaped pulse, a normalized emittance of 1.4 πmm mrad was obtained in 2006. Utilizing laser's Z-polarization, Schottky-effect-gated photocathode gun was proposed in 2006. The cathode work functions are reduced by a laser-induced Schottky effect. As a result of focusing a radially polarized laser pulse with a hollow lens in vacuum, the Z-field (Z-polarization) is generated at the cathode. (author)

Advanced Laser Technologies for High-brightness Photocathode Electron Gun

Science.gov (United States)

Tomizawa, Hiromitsu

A laser-excited photocathode RF gun is one of the most reliable high-brightness electron beam sources for XFELs. Several 3D laser shaping methods have been developed as ideal photocathode illumination sources at SPring-8 since 2001. To suppress the emittance growth caused by nonlinear space-charge forces, the 3D cylindrical UV-pulse was optimized spatially as a flattop and temporally as squarely stacked chirped pulses. This shaping system is a serial combination of a deformable mirror that adaptively shapes the spatial profile with a genetic algorithm and a UV-pulse stacker that consists of four birefringent α-BBO crystal rods for temporal shaping. Using this 3D-shaped pulse, a normalized emittance of 1.4 π mm mrad was obtained in 2006. Utilizing laser's Z-polarization, Schottky-effect-gated photocathode gun was proposed in 2006. The cathode work functions are reduced by a laser-induced Schottky effect. As a result of focusing a radially polarized laser pulse with a hollow lens in vacuum, the Z-field (Z-polarization) is generated at the cathode.

The role of the second zero-dispersion wavelength in generation of supercontinua and bright-bright soliton-pairs across the zero-dispersion wavelength: erratum

DEFF Research Database (Denmark)

Frosz, Michael Henoch; Falk, Peter Andreas; Bang, Ole

2007-01-01

An erratum is presented explaining that the observation in the original paper (Optics Express, volume 13, issue 16, page 6181-6192, 2005), of a bright-bright soliton with one color in the anomalous dispersion region and the other color in the normal dispersion region was mistaken; both parts...

High brightness K+ ion source for heavy ion fusion linear induction accelerators

International Nuclear Information System (INIS)

Henestroza, E.; Eylon, S.; Chupp, W.; Rutkowski, H.

1992-01-01

Low emittance, high current, singly charged potassium thermionic ion sources are being developed for the Induction Linac System Experiment injector, ILSE. The ILSE, now in study at LBL, will address the physics issues of particle beams in a heavy ion fusion driver scenario. The K + ion beam considered is emitted thermionically into a diode gap from alumino-silicate layers (zeolite) coated on a porous tungsten cup. The Single Beam Transport Experiment (SBTE) 120keV cesium source was redesigned and modified with the aid of an ion optics and gun design program (EGUN) to enable the evaluation of the K + source performance at high extraction currents of about 80mA from a one inch diameter source. The authors report on the source fabrication technique and performance, including total current and current density profile measurements using Faraday cups, phase space distributions using the double slit scanning technique, and source emitting surface temperature dependence on heating power using a wire pyrometer

THE BOLOCAM GALACTIC PLANE SURVEY. IX. DATA RELEASE 2 AND OUTER GALAXY EXTENSION

Energy Technology Data Exchange (ETDEWEB)

Ginsburg, Adam; Glenn, Jason; Ellsworth-Bowers, Timothy P.; Battersby, Cara; Bally, John; Stringfellow, Guy [CASA, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Rosolowsky, Erik [Department of Physics, 4-181 CCIS, University of Alberta, Edmonton, AB T6G 2E1 (Canada); Dunham, Miranda [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States); Merello, Manuel; Evans II, Neal J. [Department of Astronomy, The University of Texas, 2515 Speedway, Stop C1400 Austin, TX 78712-1205 (United States); Shirley, Yancy [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Aguirre, James, E-mail: Adam.Ginsburg@colorado.edu [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States)

2013-10-01

We present a re-reduction and expansion of the Bolocam Galactic Plane Survey (BGPS), first presented by Aguirre et al. and Rosolowsky et al. The BGPS is a 1.1 mm survey of dust emission in the Northern galactic plane, covering longitudes –10° < l < 90° and latitudes |b| < 0.°5 with a typical 1σ rms sensitivity of 30-100 mJy in a ∼33'' beam. Version 2 of the survey includes an additional ∼20 deg{sup 2} of coverage in the third and fourth quadrants and ∼2 deg{sup 2} in the first quadrant. The new data release has improved angular recovery, with complete recovery out to ∼80'' and partial recovery to ∼300'', and reduced negative bowls around bright sources resulting from the atmospheric subtraction process. We resolve the factor of 1.5 flux calibration offset between the v1.0 data release and other data sets and determine that there is no offset between v2.0 and other data sets. The v2.0 pointing accuracy is tested against other surveys and is demonstrated to be accurate and an improvement over v1.0. We present simulations and tests of the pipeline and its properties, including measurements of the pipeline's angular transfer function. The Bolocat cataloging tool was used to extract a new catalog, which includes 8594 sources, with 591 in the expanded regions. We have demonstrated that the Bolocat 40'' and 80'' apertures are accurate even in the presence of strong extended background emission. The number of sources is lower than in v1.0, but the amount of flux and area included in identified sources is larger.

Brightness-normalized Partial Least Squares Regression for hyperspectral data

International Nuclear Information System (INIS)

Feilhauer, Hannes; Asner, Gregory P.; Martin, Roberta E.; Schmidtlein, Sebastian

2010-01-01

Developed in the field of chemometrics, Partial Least Squares Regression (PLSR) has become an established technique in vegetation remote sensing. PLSR was primarily designed for laboratory analysis of prepared material samples. Under field conditions in vegetation remote sensing, the performance of the technique may be negatively affected by differences in brightness due to amount and orientation of plant tissues in canopies or the observing conditions. To minimize these effects, we introduced brightness normalization to the PLSR approach and tested whether this modification improves the performance under changing canopy and observing conditions. This test was carried out using high-fidelity spectral data (400-2510 nm) to model observed leaf chemistry. The spectral data was combined with a canopy radiative transfer model to simulate effects of varying canopy structure and viewing geometry. Brightness normalization enhanced the performance of PLSR by dampening the effects of canopy shade, thus providing a significant improvement in predictions of leaf chemistry (up to 3.6% additional explained variance in validation) compared to conventional PLSR. Little improvement was made on effects due to variable leaf area index, while minor improvement (mostly not significant) was observed for effects of variable viewing geometry. In general, brightness normalization increased the stability of model fits and regression coefficients for all canopy scenarios. Brightness-normalized PLSR is thus a promising approach for application on airborne and space-based imaging spectrometer data.

A spectral k-means approach to bright-field cell image segmentation.

Science.gov (United States)

Bradbury, Laura; Wan, Justin W L

2010-01-01

Automatic segmentation of bright-field cell images is important to cell biologists, but difficult to complete due to the complex nature of the cells in bright-field images (poor contrast, broken halo, missing boundaries). Standard approaches such as level set segmentation and active contours work well for fluorescent images where cells appear as round shape, but become less effective when optical artifacts such as halo exist in bright-field images. In this paper, we present a robust segmentation method which combines the spectral and k-means clustering techniques to locate cells in bright-field images. This approach models an image as a matrix graph and segment different regions of the image by computing the appropriate eigenvectors of the matrix graph and using the k-means algorithm. We illustrate the effectiveness of the method by segmentation results of C2C12 (muscle) cells in bright-field images.

LENSING NOISE IN MILLIMETER-WAVE GALAXY CLUSTER SURVEYS

International Nuclear Information System (INIS)

Hezaveh, Yashar; Vanderlinde, Keith; Holder, Gilbert; De Haan, Tijmen

2013-01-01

We study the effects of gravitational lensing by galaxy clusters of the background of dusty star-forming galaxies (DSFGs) and the cosmic microwave background (CMB), and examine the implications for Sunyaev-Zel'dovich-based (SZ) galaxy cluster surveys. At the locations of galaxy clusters, gravitational lensing modifies the probability distribution of the background flux of the DSFGs as well as the CMB. We find that, in the case of a single-frequency 150 GHz survey, lensing of DSFGs leads both to a slight increase (∼10%) in detected cluster number counts (due to a ∼50% increase in the variance of the DSFG background, and hence an increased Eddington bias) and a rare (occurring in ∼2% of clusters) 'filling-in' of SZ cluster signals by bright strongly lensed background sources. Lensing of the CMB leads to a ∼55% reduction in CMB power at the location of massive galaxy clusters in a spatially matched single-frequency filter, leading to a net decrease in detected cluster number counts. We find that the increase in DSFG power and decrease in CMB power due to lensing at cluster locations largely cancel, such that the net effect on cluster number counts for current SZ surveys is subdominant to Poisson errors

T1 bright appendix sign to exclude acute appendicitis in pregnant women

International Nuclear Information System (INIS)

Shin, Ilah; An, Chansik; Lim, Joon Seok; Kim, Myeong-Jin; Chung, Yong Eun

2017-01-01

To evaluate the diagnostic value of the T1 bright appendix sign for the diagnosis of acute appendicitis in pregnant women. This retrospective study included 125 pregnant women with suspected appendicitis who underwent magnetic resonance (MR) imaging. The T1 bright appendix sign was defined as a high intensity signal filling more than half length of the appendix on T1-weighted imaging. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the T1 bright appendix sign for normal appendix identification were calculated in all patients and in those with borderline-sized appendices (6-7 mm). The T1 bright appendix sign was seen in 51% of patients with normal appendices, but only in 4.5% of patients with acute appendicitis. The overall sensitivity, specificity, PPV, and NPV of the T1 bright appendix sign for normal appendix diagnosis were 44.9%, 95.5%, 97.6%, and 30.0%, respectively. All four patients with borderline sized appendix with appendicitis showed negative T1 bright appendix sign. The T1 bright appendix sign is a specific finding for the diagnosis of a normal appendix in pregnant women with suspected acute appendicitis. (orig.)

T1 bright appendix sign to exclude acute appendicitis in pregnant women

Energy Technology Data Exchange (ETDEWEB)

Shin, Ilah; An, Chansik; Lim, Joon Seok; Kim, Myeong-Jin; Chung, Yong Eun [Yonsei University College of Medicine, Department of Radiology, Research Institute of Radiological Science, Severance Hospital, 50-1 Yonsei-ro, Seodaemun-gu, Seoul (Korea, Republic of)

2017-08-15

To evaluate the diagnostic value of the T1 bright appendix sign for the diagnosis of acute appendicitis in pregnant women. This retrospective study included 125 pregnant women with suspected appendicitis who underwent magnetic resonance (MR) imaging. The T1 bright appendix sign was defined as a high intensity signal filling more than half length of the appendix on T1-weighted imaging. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the T1 bright appendix sign for normal appendix identification were calculated in all patients and in those with borderline-sized appendices (6-7 mm). The T1 bright appendix sign was seen in 51% of patients with normal appendices, but only in 4.5% of patients with acute appendicitis. The overall sensitivity, specificity, PPV, and NPV of the T1 bright appendix sign for normal appendix diagnosis were 44.9%, 95.5%, 97.6%, and 30.0%, respectively. All four patients with borderline sized appendix with appendicitis showed negative T1 bright appendix sign. The T1 bright appendix sign is a specific finding for the diagnosis of a normal appendix in pregnant women with suspected acute appendicitis. (orig.)

Quantitative measurement of brightness from living cells in the presence of photodepletion.

Directory of Open Access Journals (Sweden)

Kwang-Ho Hur

Full Text Available The brightness of fluorescently labeled proteins provides an excellent marker for identifying protein interactions in living cells. Quantitative interpretation of brightness, however, hinges on a detailed understanding of the processes that affect the signal fluctuation of the fluorescent label. Here, we focus on the cumulative influence of photobleaching on brightness measurements in cells. Photobleaching within the finite volume of the cell leads to a depletion of the population of fluorescently labeled proteins with time. The process of photodepletion reduces the fluorescence signal which biases the analysis of brightness data. Our data show that even small reductions in the signal can introduce significant bias into the analysis of the data. We develop a model that quantifies the bias and introduce an analysis method that accurately determines brightness in the presence of photodepletion as verified by experiments with mammalian and yeast cells. In addition, photodepletion experiments with the fluorescent protein EGFP reveal the presence of a photoconversion process, which leads to a marked decrease in the brightness of the EGFP protein. We also identify conditions where the effect of EGFP's photoconversion on brightness experiments can be safely ignored.

Dark and bright solitons in a quasi-one-dimensional Bose-Einstein condensate

International Nuclear Information System (INIS)

Wang, Shun-Jin; Jia, Cheng-Long; An, Jun-Hong; Zhao, Dun; Luo, Hong-Gang

2003-01-01

The analytical dark and bright soliton solutions of the one-dimensional Gross-Pitaevskii equation with a confining potential are obtained. For the bright soliton, the recent experimental finding is studied, and the particle number of the soliton and the window of the particle numbers for the bright soliton to occur are estimated analytically and in good agreement with the experimental data. The existence of dark soliton for the attractive interaction and bright soliton for the repulsive interaction is predicted under proper conditions

CHANDRA ACIS SURVEY OF X-RAY POINT SOURCES IN NEARBY GALAXIES. II. X-RAY LUMINOSITY FUNCTIONS AND ULTRALUMINOUS X-RAY SOURCES

Energy Technology Data Exchange (ETDEWEB)

Wang, Song; Qiu, Yanli; Liu, Jifeng [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Bregman, Joel N., E-mail: songw@bao.ac.cn, E-mail: jfliu@bao.ac.cn [University of Michigan, Ann Arbor, MI 48109 (United States)

2016-09-20

Based on the recently completed Chandra /ACIS survey of X-ray point sources in nearby galaxies, we study the X-ray luminosity functions (XLFs) for X-ray point sources in different types of galaxies and the statistical properties of ultraluminous X-ray sources (ULXs). Uniform procedures are developed to compute the detection threshold, to estimate the foreground/background contamination, and to calculate the XLFs for individual galaxies and groups of galaxies, resulting in an XLF library of 343 galaxies of different types. With the large number of surveyed galaxies, we have studied the XLFs and ULX properties across different host galaxy types, and confirm with good statistics that the XLF slope flattens from lenticular ( α ∼ 1.50 ± 0.07) to elliptical (∼1.21 ± 0.02), to spirals (∼0.80 ± 0.02), to peculiars (∼0.55 ± 0.30), and to irregulars (∼0.26 ± 0.10). The XLF break dividing the neutron star and black hole binaries is also confirmed, albeit at quite different break luminosities for different types of galaxies. A radial dependency is found for ellipticals, with a flatter XLF slope for sources located between D {sub 25} and 2 D {sub 25}, suggesting the XLF slopes in the outer region of early-type galaxies are dominated by low-mass X-ray binaries in globular clusters. This study shows that the ULX rate in early-type galaxies is 0.24 ± 0.05 ULXs per surveyed galaxy, on a 5 σ confidence level. The XLF for ULXs in late-type galaxies extends smoothly until it drops abruptly around 4 × 10{sup 40} erg s{sup −1}, and this break may suggest a mild boundary between the stellar black hole population possibly including 30 M {sub ⊙} black holes with super-Eddington radiation and intermediate mass black holes.

Quadrature measurements of a bright squeezed state via sideband swapping

DEFF Research Database (Denmark)

Schneider, J.; Glockl, O.; Leuchs, G.

2009-01-01

The measurement of an arbitrary quadrature of a bright quantum state of light is a commonly requested action in many quantum information protocols, but it is experimentally challenging with previously proposed schemes. We suggest that the quadrature be measured at a specific sideband frequency...... of a bright quantum state by transferring the sideband modes under interrogation to a vacuum state and subsequently measuring the quadrature via homodyne detection. The scheme is implemented experimentally, and it is successfully tested with a bright squeezed state of light....

Condensate bright solitons under transverse confinement

International Nuclear Information System (INIS)

Salasnich, L.; Reatto, L.; Parola, A.

2002-01-01

We investigate the dynamics of Bose-Einstein condensate bright solitons made of alkali-metal atoms with negative scattering length and under harmonic confinement in the transverse direction. Contrary to the one-dimensional (1D) case, the 3D bright soliton exists only below a critical attractive interaction that depends on the extent of confinement. Such a behavior is also found in multisoliton condensates with box boundary conditions. We obtain numerical and analytical estimates of the critical strength beyond which the solitons do not exist. By using an effective 1D nonpolynomial nonlinear Schroedinger equation, which accurately takes into account the transverse dynamics of cigarlike condensates, we numerically simulate the dynamics of the 'soliton train' reported in a recent experiment [Nature (London) 417, 150 (2002)]. Then, analyzing the macroscopic quantum tunneling of the bright soliton on a Gaussian barrier, we find that its interference in the tunneling region is strongly suppressed with respect to nonsolitonic case; moreover, the tunneling through a barrier breaks the shape invariance of the matter wave. Finally, we show that the collapse of the soliton is induced by the scattering on the barrier or by the collision with another matter wave when the density reaches a critical value, for which we derive an accurate analytical formula

Possible Bright Starspots on TRAPPIST-1

Science.gov (United States)

Morris, Brett M.; Agol, Eric; Davenport, James R. A.; Hawley, Suzanne L.

2018-04-01

The M8V star TRAPPIST-1 hosts seven roughly Earth-sized planets and is a promising target for exoplanet characterization. Kepler/K2 Campaign 12 observations of TRAPPIST-1 in the optical show an apparent rotational modulation with a 3.3-day period, though that rotational signal is not readily detected in the Spitzer light curve at 4.5 μm. If the rotational modulation is due to starspots, persistent dark spots can be excluded from the lack of photometric variability in the Spitzer light curve. We construct a photometric model for rotational modulation due to photospheric bright spots on TRAPPIST-1 that is consistent with both the Kepler and Spitzer light curves. The maximum-likelihood model with three spots has typical spot sizes of R spot/R ⋆ ≈ 0.004 at temperature T spot ≳ 5300 ± 200 K. We also find that large flares are observed more often when the brightest spot is facing the observer, suggesting a correlation between the position of the bright spots and flare events. In addition, these flares may occur preferentially when the spots are increasing in brightness, which suggests that the 3.3-day periodicity may not be a rotational signal, but rather a characteristic timescale of active regions.

SKYMONITOR: A Global Network for Sky Brightness Measurements

Science.gov (United States)

Davis, Donald R.; Mckenna, D.; Pulvermacher, R.; Everett, M.

2010-01-01

We are implementing a global network to measure sky brightness at dark-sky critical sites with the goal of creating a multi-decade database. The heart of this project is the Night Sky Brightness Monitor (NSBM), an autonomous 2 channel photometer which measures night sky brightness in the visual wavelengths (Mckenna et al, AAS 2009). Sky brightness is measured every minute at two elevation angles typically zenith and 20 degrees to monitor brightness and transparency. The NSBM consists of two parts, a remote unit and a base station with an internet connection. Currently these devices use 2.4 Ghz transceivers with a range of 100 meters. The remote unit is battery powered with daytime recharging using a solar panel. Data received by the base unit is transmitted via email protocol to IDA offices in Tucson where it will be collected, archived and made available to the user community via a web interface. Two other versions of the NSBM are under development: one for radio sensitive areas using an optical fiber link and the second that reads data directly to a laptop for sites without internet access. NSBM units are currently undergoing field testing at two observatories. With support from the National Science Foundation, we will construct and install a total of 10 units at astronomical observatories. With additional funding, we will locate additional units at other sites such as National Parks, dark-sky preserves and other sites where dark sky preservation is crucial. We will present the current comparison with the National Park Service sky monitoring camera. We anticipate that the SKYMONITOR network will be functioning by the end of 2010.

Temporary blinding from bright light sources as a significant impact on occupational safety and health

International Nuclear Information System (INIS)

Reidenbach, Hans-Dieter

2008-01-01

Low power laser and high-brightness LEDs (HB-LEDs) have been applied in specially developed and computer assisted test setups in order to determine the duration and progression of colours in afterimages, the disturbance of visual acuity as well as the impairment of colour and contrast vision. Interrelationships between wavelength, exposure duration, optical power and energy have been investigated. Afterimage durations up to 300 seconds were found if the fovea of the human retina is irradiated from a laser beam at less than 30 μW, whereas lower values are valid in the Parafoveal region and in the periphery. The visual acuity was strongly reduced during about 30 % of the afterimage time. The time-dependent progression of the afterimage colours was determined for 4 different dominant wavelengths of HB-LEDs, i.e. 455 nm, 530 nm, 590 nm and 625 nm, in the power range between 0.05 m W and 0.5 m W for exposure durations between 0.5 s and 5 s. The flight of colours obtained with 5 test persons is given as 8-bit RGB-values and illustrated as a function of the applied optical energy in the CIE chromaticity diagram together with the respective total afterimage durations. The colour contrast capability was investigated for 3 volunteers with specially developed test charts in 7 colours, namely without and after glare from 4 coloured high-brightness LEDs. Each subject completed 56 time-consuming tests since adequate adaptation was necessary between the respective tests. Glare increases the identification times about 14 s and 16 s and even stronger impairment is observable especially at low colour contrast. Tests with 40 subjects and 4 different pseudoisochromatic colour plates have shown that colour vision was impaired for periods between 27 s and 186 s depending on the applied colour plate and respective LED colour. Such relatively long lasting visual disturbances could be of particular concern connected with performing safety critical operations such as working with machines

A surface brightness analysis of eight RR Lyrae stars

International Nuclear Information System (INIS)

Hawley, S.L.; Barnes, T.G. III; Moffett, T.J.

1987-01-01

The authors have used a surface brightness, (V-R) relation to analyze new contemporaneous photometry and radial velocity data for 6 RR-ab type stars and to re-analyze previously published data for RR Lyrae and X Arietis. Systematic effects were found in the surface brightness at phases near minimum radius. Excluding these phases, they determine the slope of the surface brightness relation and the mean radius for each star. They also find a zero point which includes both a distance term and the zero point of the surface brightness relation. The sample includes stars with Preston's metallicity indicator ΔS = 0 to 9, with periods ranging from 0.397 days to 0.651 days. Their results indicate a log(R/R solar ) vs. log P relation in the sense that stars with longer periods have larger radii, in agreement with theoretical predictions. Their radii are consistent with bolometric magnitudes in the range 0.2 - 0.8 magnitude but accurate magnitudes must await a reliable T e - color calibration

Solar brightness distribution at 8.6 mm from interferometer observations

International Nuclear Information System (INIS)

Kawabata, K.; Fujishita, M.; Kato, T.; Ogawa, H.; Omodaka, T.

1980-01-01

The radial brightness distribution of the quiet Sun at 8.6 mm is synthesized from observations using a sixteen element east-west interferometer in Nagoya. The observed brightness is flat from the disk center to 0.8 Rsub(sun). A slight darkening appeared between 0.8 Rsub(sun) and the limb. No evidence if the bright ring near the limb is found. The radio radius at 8.6 mm is 1.015 +- 0.005 Rsub(sun). In addition there exists a coronal component just outside the radio limb. (orig.)

Cross-dimensional mapping of number, length and brightness by preschool children.

Directory of Open Access Journals (Sweden)

Maria Dolores de Hevia

Full Text Available Human adults in diverse cultures, children, infants, and non-human primates relate number to space, but it is not clear whether this ability reflects a specific and privileged number-space mapping. To investigate this possibility, we tested preschool children in matching tasks where the dimensions of number and length were mapped both to one another and to a third dimension, brightness. Children detected variation on all three dimensions, and they reliably performed mappings between number and length, and partially between brightness and length, but not between number and brightness. Moreover, children showed reliably better mapping of number onto the dimension of length than onto the dimension of brightness. These findings suggest that number establishes a privileged mapping with the dimension of length, and that other dimensions, including brightness, can be mapped onto length, although less efficiently. Children's adeptness at number-length mappings suggests that these two dimensions are intuitively related by the end of the preschool years.

T1 bright appendix sign to exclude acute appendicitis in pregnant women.

Science.gov (United States)

Shin, Ilah; An, Chansik; Lim, Joon Seok; Kim, Myeong-Jin; Chung, Yong Eun

2017-08-01

To evaluate the diagnostic value of the T1 bright appendix sign for the diagnosis of acute appendicitis in pregnant women. This retrospective study included 125 pregnant women with suspected appendicitis who underwent magnetic resonance (MR) imaging. The T1 bright appendix sign was defined as a high intensity signal filling more than half length of the appendix on T1-weighted imaging. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the T1 bright appendix sign for normal appendix identification were calculated in all patients and in those with borderline-sized appendices (6-7 mm). The T1 bright appendix sign was seen in 51% of patients with normal appendices, but only in 4.5% of patients with acute appendicitis. The overall sensitivity, specificity, PPV, and NPV of the T1 bright appendix sign for normal appendix diagnosis were 44.9%, 95.5%, 97.6%, and 30.0%, respectively. All four patients with borderline sized appendix with appendicitis showed negative T1 bright appendix sign. The T1 bright appendix sign is a specific finding for the diagnosis of a normal appendix in pregnant women with suspected acute appendicitis. • Magnetic resonance imaging is increasingly used in emergency settings. • Acute appendicitis is the most common cause of acute abdomen. • Magnetic resonance imaging is widely used in pregnant population. • T1 bright appendix sign can be a specific sign representing normal appendix.

State survey of silviculture nonpoint source programs: a comparison of the 2000 northeastern and national results

Science.gov (United States)

Pamela J. Edwards; Gordon W. Stuart

2002-01-01

The National Association of State Foresters conducts surveys of silviculture nonpoint source (NPS) pollution control programs to measure progress and identify needs. The 2000 survey results are summarized here for the nation and for the 20-state northeastern region. Current emphasis of NPS pollution programs is on education, training, and monitoring. Educational...

Survey on the Sources of Information in Science, Technology and Commerce in the State of Penang, Malaysia

Science.gov (United States)

Tee, Lim Huck; Fong, Tang Wan

1973-01-01

Penang, Malaysia is undergoing rapid industrialization to stimulate its economy. A survey was conducted to determine what technical, scientific, and commercial information sources were available. Areas covered in the survey were library facilities, journals, commercial reference works and audio-visual materials. (DH)

Measuring our Universe from Galaxy Redshift Surveys

Directory of Open Access Journals (Sweden)

Lahav Ofer

2004-07-01

Full Text Available Galaxy redshift surveys have achieved significant progress over the last couple of decades. Those surveys tell us in the most straightforward way what our local Universe looks like. While the galaxy distribution traces the bright side of the Universe, detailed quantitative analyses of the data have even revealed the dark side of the Universe dominated by non-baryonic dark matter as well as more mysterious dark energy (or Einstein's cosmological constant. We describe several methodologies of using galaxy redshift surveys as cosmological probes, and then summarize the recent results from the existing surveys. Finally we present our views on the future of redshift surveys in the era of precision cosmology.

A Bright Short Period M-M Eclipsing Binary from the KELT Survey: Magnetic Activity and the Mass-Radius Relationship for M Dwarfs

Science.gov (United States)

Lubin, Jack B.; Rodriguez, Joseph E.; Zhou, George; Conroy, Kyle E.; Stassun, Keivan G.; Collins, Karen; Stevens, Daniel J.; Labadie-Bartz, Jonathan; Stockdale, Christopher; Myers, Gordon; Colón, Knicole D.; Bento, Joao; Kehusmaa, Petri; Petrucci, Romina; Jofré, Emiliano; Quinn, Samuel N.; Lund, Michael B.; Kuhn, Rudolf B.; Siverd, Robert J.; Beatty, Thomas G.; Harlingten, Caisey; Pepper, Joshua; Gaudi, B. Scott; James, David; Jensen, Eric L. N.; Reichart, Daniel; Kedziora-Chudczer, Lucyna; Bailey, Jeremy; Melville, Graeme

2017-08-01

We report the discovery of KELT J041621-620046, a moderately bright (J ˜ 10.2) M-dwarf eclipsing binary system at a distance of 39 ± 3 pc. KELT J041621-620046 was first identified as an eclipsing binary using observations from the Kilodegree Extremely Little Telescope (KELT) survey. The system has a short orbital period of ˜1.11 days and consists of components with {M}1={0.447}+0.052-0.047 {M}⊙ and {M}2={0.399}+0.046-0.042 {M}⊙ in nearly circular orbits. The radii of the two stars are {R}1={0.540}+0.034-0.032 {R}⊙ and {\\text{}}{R}2=0.453+/- 0.017 {R}⊙ . Full system and orbital properties were determined (to ˜10% error) by conducting an EBOP (Eclipsing Binary Orbit Program) global modeling of the high precision photometric and spectroscopic observations obtained by the KELT Follow-up Network. Each star is larger by 17%-28% and cooler by 4%-10% than predicted by standard (non-magnetic) stellar models. Strong Hα emission indicates chromospheric activity in both stars. The observed radii and temperature discrepancies for both components are more consistent with those predicted by empirical relations that account for convective suppression due to magnetic activity.

Fifty shades of white: how white feather brightness differs among species

Science.gov (United States)

Igic, Branislav; D'Alba, Liliana; Shawkey, Matthew D.

2018-04-01

White colouration is a common and important component of animal visual signalling and camouflage, but how and why it varies across species is poorly understood. White is produced by wavelength-independent and diffuse scattering of light by the internal structures of materials, where the degree of brightness is related to the amount of light scattered. Here, we investigated the morphological basis of brightness differences among unpigmented pennaceous regions of white body feathers across 61 bird species. Using phylogenetically controlled comparisons of reflectance and morphometric measurements, we show that brighter white feathers had larger and internally more complex barbs than duller white feathers. Higher brightness was also associated with more closely packed barbs and barbules, thicker and longer barbules, and rounder and less hollow barbs. Larger species tended to have brighter white feathers than smaller species because they had thicker and more complex barbs, but aquatic species were not significantly brighter than terrestrial species. As similar light scattering principals affect the brightness of chromatic signals, not just white colours, these findings help broaden our general understanding of the mechanisms that affect plumage brightness. Future studies should examine how feather layering on a bird's body contributes to differences between brightness of white plumage patches within and across species.

Characterizing the Motion of Solar Magnetic Bright Points at High Resolution

Science.gov (United States)

Van Kooten, Samuel J.; Cranmer, Steven R.

2017-11-01

Magnetic bright points in the solar photosphere, visible in both continuum and G-band images, indicate footpoints of kilogauss magnetic flux tubes extending to the corona. The power spectrum of bright-point motion is thus also the power spectrum of Alfvén wave excitation, transporting energy up flux tubes into the corona. This spectrum is a key input in coronal and heliospheric models. We produce a power spectrum of bright-point motion using radiative magnetohydrodynamic simulations, exploiting spatial resolution higher than can be obtained in present-day observations, while using automated tracking to produce large data quantities. We find slightly higher amounts of power at all frequencies compared to observation-based spectra, while confirming the spectrum shape of recent observations. This also provides a prediction for observations of bright points with DKIST, which will achieve similar resolution and high sensitivity. We also find a granule size distribution in support of an observed two-population distribution, and we present results from tracking passive tracers, which show a similar power spectrum to that of bright points. Finally, we introduce a simplified, laminar model of granulation, with which we explore the roles of turbulence and of the properties of the granulation pattern in determining bright-point motion.

Selection of high-brightness, laser-driven cathodes for electron accelerators and FELS

International Nuclear Information System (INIS)

Oettinger, P.E.

1987-01-01

Very intense, low emittance pulsed beams of electrons can be generated from laser-driven cathodes either by thermionic- or photo-emission. Several hundreds of amperes of electrons per square centimeter were observed for pulse lengths up to 50 ns. A normalized beam brightness of 10 7 A/cm 2 /rad 2 has been measured. These beams can be emission-gated at the cathode surface by modulating the laser-beam. Such beam bunching will generate picosecond-to-microsecond-long pulses at the source. A variety of cathodes are described, and a method of selection for specific applications is presented

First results from the high-brightness x-ray spectroscopy beamline at ALS

Energy Technology Data Exchange (ETDEWEB)

Perera, R.C.C.; Ng, W.; Jones, G. [Lawrence Berkeley National Lab., CA (United States)] [and others

1997-04-01

Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1-6 keV photon-energy range, designed to achieve the goal of high brightness at the sample for use in the X-ray Atomic and Molecular Spectroscopy (XAMS) science, surface and interface science, biology and x-ray optical development programs at ALS. X-ray absorption and time of flight photo emission measurements in 2 - 5 keV photon energy in argon along with the flux, resolution, spot size and stability of the beamline will be discussed. Prospects for future XAMS measurements will also be presented.

Who purchases cigarettes from cheaper sources in China? Findings from the ITC China Survey.

Science.gov (United States)

Yao, Tingting; Huang, Jidong; Sung, Hai-Yen; Ong, Michael K; Mao, Zhengzhong; Jiang, Yuan; Fong, Geoffrey T; Max, Wendy

2014-03-01

The availability of cigarettes from cheaper sources constitutes a major challenge to public health throughout the world, including China, because it may counteract price-based tobacco control policies. The goal of this study was to identify factors associated with purchasing cigarettes from cheaper sources among adult smokers in China. Data were analysed from Waves 1 to 3 of the International Tobacco Control China Survey conducted in 2006-2009 among adult smokers in six cities in China (N=7980). One survey question asked, "In the last 6 months, have you purchased cheaper cigarettes than you can get from local stores for economic reasons?" We examined whether sociodemographic factors and smoking intensity were associated with purchasing cigarettes from cheaper sources using the general estimating equations model. Sociodemographic factors considered were gender, age, marital status, monthly household income, education, employment status and city of residence. 15.6% of smokers reported purchasing cigarettes from cheaper sources. After controlling for other covariates, the associations of the behaviour of purchasing cigarettes from cheaper sources with age (adjusted OR (AOR)=1.49, 95% CI 1.17 to 3.92 for age 18-24 compared with age 55+) and with income (AOR=2.93, 95% CI 2.27 to 3.79 for low income compared with high income) were statistically significant, but there was no statistically significant relationship with smoking intensity. Our findings indicate that young and low-income smokers are more likely than older and high-income smokers to purchase cigarettes from cheaper sources in China. Tobacco control policies that reduce the availability of cigarettes from cheaper sources could have an impact on reducing cigarette consumption among young and low-income smokers in China.

On the Relation Between Facular Bright Points and the Magnetic Field

Science.gov (United States)

Berger, Thomas; Shine, Richard; Tarbell, Theodore; Title, Alan; Scharmer, Goran

1994-12-01

Multi-spectral images of magnetic structures in the solar photosphere are presented. The images were obtained in the summers of 1993 and 1994 at the Swedish Solar Telescope on La Palma using the tunable birefringent Solar Optical Universal Polarimeter (SOUP filter), a 10 Angstroms wide interference filter tuned to 4304 Angstroms in the band head of the CH radical (the Fraunhofer G-band), and a 3 Angstroms wide interference filter centered on the Ca II--K absorption line. Three large format CCD cameras with shuttered exposures on the order of 10 msec and frame rates of up to 7 frames per second were used to create time series of both quiet and active region evolution. The full field--of--view is 60times 80 arcseconds (44times 58 Mm). With the best seeing, structures as small as 0.22 arcseconds (160 km) in diameter are clearly resolved. Post--processing of the images results in rigid coalignment of the image sets to an accuracy comparable to the spatial resolution. Facular bright points with mean diameters of 0.35 arcseconds (250 km) and elongated filaments with lengths on the order of arcseconds (10(3) km) are imaged with contrast values of up to 60 % by the G--band filter. Overlay of these images on contemporal Fe I 6302 Angstroms magnetograms and Ca II K images reveals that the bright points occur, without exception, on sites of magnetic flux through the photosphere. However, instances of concentrated and diffuse magnetic flux and Ca II K emission without associated bright points are common, leading to the conclusion that the presence of magnetic flux is a necessary but not sufficient condition for the occurence of resolvable facular bright points. Comparison of the G--band and continuum images shows a complex relation between structures in the two bandwidths: bright points exceeding 350 km in extent correspond to distinct bright structures in the continuum; smaller bright points show no clear relation to continuum structures. Size and contrast statistical cross

THE ALMA SPECTROSCOPIC SURVEY IN THE HUBBLE ULTRA DEEP FIELD: IMPLICATIONS FOR SPECTRAL LINE INTENSITY MAPPING AT MILLIMETER WAVELENGTHS AND CMB SPECTRAL DISTORTIONS

Energy Technology Data Exchange (ETDEWEB)

Carilli, C. L.; Walter, F. [National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM 87801 (United States); Chluba, J. [Jodrell Bank Centre for Astrophysics, University of Manchester, Oxford Road, M13 9PL (United Kingdom); Decarli, R. [Max-Planck Institute for Astronomy, D-69117 Heidelberg (Germany); Aravena, M. [Nucleo de Astronomia, Facultad de Ingenieria, Universidad Diego Portales, Av. Ejercito 441, Santiago (Chile); Wagg, J. [Square Kilometre Array Organisation, Lower Withington, Cheshire (United Kingdom); Popping, G. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748, Garching (Germany); Cortes, P. [Joint ALMA Observatory—ESO, Av. Alonso de Cordova, 3104, Santiago (Chile); Hodge, J. [Leiden Observatory, Leiden University, Niels Bohrweg 2, NL2333 RA Leiden (Netherlands); Weiss, A. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Bertoldi, F. [Argelander Institute for Astronomy, University of Bonn, Auf dem Hügel 71, D-53121 Bonn (Germany); Riechers, D., E-mail: ccarilli@aoc.nrao.edu [Cornell University, 220 Space Sciences Building, Ithaca, NY 14853 (United States)

2016-12-10

We present direct estimates of the mean sky brightness temperature in observing bands around 99 and 242 GHz due to line emission from distant galaxies. These values are calculated from the summed line emission observed in a blind, deep survey for spectral line emission from high redshift galaxies using ALMA (the ALMA spectral deep field observations “ASPECS” survey). In the 99 GHz band, the mean brightness will be dominated by rotational transitions of CO from intermediate and high redshift galaxies. In the 242 GHz band, the emission could be a combination of higher order CO lines, and possibly [C ii] 158 μ m line emission from very high redshift galaxies ( z  ∼ 6–7). The mean line surface brightness is a quantity that is relevant to measurements of spectral distortions of the cosmic microwave background, and as a potential tool for studying large-scale structures in the early universe using intensity mapping. While the cosmic volume and the number of detections are admittedly small, this pilot survey provides a direct measure of the mean line surface brightness, independent of conversion factors, excitation, or other galaxy formation model assumptions. The mean surface brightness in the 99 GHZ band is: T{sub B}  = 0.94 ± 0.09 μ K. In the 242 GHz band, the mean brightness is: T{sub B}  = 0.55 ± 0.033 μ K. These should be interpreted as lower limits on the average sky signal, since we only include lines detected individually in the blind survey, while in a low resolution intensity mapping experiment, there will also be the summed contribution from lower luminosity galaxies that cannot be detected individually in the current blind survey.

ALMA Discovery of Solar Umbral Brightness Enhancement at λ = 3 mm

Energy Technology Data Exchange (ETDEWEB)

Iwai, Kazumasa [Institute for Space-Earth Environmental Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 (Japan); Loukitcheva, Maria [Center for Solar-Terrestrial Research, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, Newark, NJ 07102 (United States); Shimojo, Masumi [Chile Observatory, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Solanki, Sami K. [Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, D-37073 Göttingen (Germany); White, Stephen M., E-mail: k.iwai@isee.nagoya-u.ac.jp [Space Vehicles Directorate, Air Force Research Laboratory, Albuquerque, NM (United States)

2017-06-01

We report the discovery of a brightness enhancement in the center of a large sunspot umbra at a wavelength of 3 mm using the Atacama Large Millimeter/sub-millimeter Array (ALMA). Sunspots are among the most prominent features on the solar surface, but many of their aspects are surprisingly poorly understood. We analyzed a λ = 3 mm (100 GHz) mosaic image obtained by ALMA that includes a large sunspot within the active region AR12470, on 2015 December 16. The 3 mm map has a 300″ × 300″ field of view and 4.″9 × 2.″2 spatial resolution, which is the highest spatial resolution map of an entire sunspot in this frequency range. We find a gradient of 3 mm brightness from a high value in the outer penumbra to a low value in the inner penumbra/outer umbra. Within the inner umbra, there is a marked increase in 3 mm brightness temperature, which we call an umbral brightness enhancement. This enhanced emission corresponds to a temperature excess of 800 K relative to the surrounding inner penumbral region and coincides with excess brightness in the 1330 and 1400 Å slit-jaw images of the Interface Region Imaging Spectrograph ( IRIS ), adjacent to a partial lightbridge. This λ = 3 mm brightness enhancement may be an intrinsic feature of the sunspot umbra at chromospheric heights, such as a manifestation of umbral flashes, or it could be related to a coronal plume, since the brightness enhancement was coincident with the footpoint of a coronal loop observed at 171 Å.

A Survey of Information Source Preferences of Parents of Individuals with Autism Spectrum Disorder.

Science.gov (United States)

Gibson, Amelia N; Kaplan, Samantha; Vardell, Emily

2017-07-01

For parents of children with an Autism spectrum disorder (ASD), high quality, easily accessible information and a strong peer network can be the key to raising a happy, healthy child, and maintaining family well-being and emotional resilience. This article reports the findings of an anonymous survey examining the information source preferences for 935 parents of individuals with ASDs in North Carolina. Data indicates that parents show similar information seeking patterns across the age spectrum, that availability of information (as indicated by overall information source selection) decrease as children age. It also shows that parents rely heavily on local sources of information, preferring them to nonlocal sources (such as the internet) for many types of information.

Bright-Dark Mixed N-Soliton Solutions of the Multi-Component Mel'nikov System

Science.gov (United States)

Han, Zhong; Chen, Yong; Chen, Junchao

2017-10-01

By virtue of the Kadomtsev-Petviashvili (KP) hierarchy reduction technique, we construct the general bright-dark mixed N-soliton solution to the multi-component Mel'nikov system. This multi-component system comprised of multiple (say M) short-wave components and one long-wave component with all possible combinations of nonlinearities including all-positive, all-negative and mixed types. Firstly, the two-bright-one-dark (2-b-1-d) and one-bright-two-dark (1-b-2-d) mixed N-soliton solutions in short-wave components of the three-component Mel'nikov system are derived in detail. Then we extend our analysis to the M-component Mel'nikov system to obtain its general mixed N-soliton solution. The formula obtained unifies the all-bright, all-dark and bright-dark mixed N-soliton solutions. For the collision of two solitons, an asymptotic analysis shows that for an M-component Mel'nikov system with M ≥ 3, inelastic collision takes place, resulting in energy exchange among the short-wave components supporting bright solitons only if the bright solitons appear in at least two short-wave components. In contrast, the dark solitons in the short-wave components and the bright solitons in the long-wave component always undergo elastic collision which is only accompanied by a position shift.

An unusually strong Einstein ring in the radio source PKS1830-211

International Nuclear Information System (INIS)

Jauncey, D.L.

1991-01-01

RADIO observations of the strong, flat-spectrum radio source PKS1830-211 revealed a double structure, with a separation of 1 arcsec, suggesting that it might be a gravitationally lensed object. We have now obtained high-resolution radio images of PKS1830-211 from several interferometric radiotelescope networks, which show an unusual elliptical ring-like structure connecting the two brighter components. The presence of the ring, and the similarity of the two brighter spots, argue strongly that this is indeed a gravitationally lensed system, specifically an Einstein ring in which lens and lensed object are closely aligned. Although the source is close to the galactic plane, it seems that both the lens and background (lensed) object are extragalactic. This object is one hundred times brighter than either of the two previously discovered radio Einstein rings, and is among the six brightest flat-spectrum sources in the sky. Its brightness makes it a peculiar object: it must involve either a chance alignment of a lensing object with an unusually bright background source, or an alignment with a less bright object but amplified to an unusual degree. (author)

The Einstein@Home Gamma-ray Pulsar Survey. II. Source Selection, Spectral Analysis, and Multiwavelength Follow-up

Science.gov (United States)

Wu, J.; Clark, C. J.; Pletsch, H. J.; Guillemot, L.; Johnson, T. J.; Torne, P.; Champion, D. J.; Deneva, J.; Ray, P. S.; Salvetti, D.; Kramer, M.; Aulbert, C.; Beer, C.; Bhattacharyya, B.; Bock, O.; Camilo, F.; Cognard, I.; Cuéllar, A.; Eggenstein, H. B.; Fehrmann, H.; Ferrara, E. C.; Kerr, M.; Machenschalk, B.; Ransom, S. M.; Sanpa-Arsa, S.; Wood, K.

2018-02-01

We report on the analysis of 13 gamma-ray pulsars discovered in the Einstein@Home blind search survey using Fermi Large Area Telescope (LAT) Pass 8 data. The 13 new gamma-ray pulsars were discovered by searching 118 unassociated LAT sources from the third LAT source catalog (3FGL), selected using the Gaussian Mixture Model machine-learning algorithm on the basis of their gamma-ray emission properties being suggestive of pulsar magnetospheric emission. The new gamma-ray pulsars have pulse profiles and spectral properties similar to those of previously detected young gamma-ray pulsars. Follow-up radio observations have revealed faint radio pulsations from two of the newly discovered pulsars and enabled us to derive upper limits on the radio emission from the others, demonstrating that they are likely radio-quiet gamma-ray pulsars. We also present results from modeling the gamma-ray pulse profiles and radio profiles, if available, using different geometric emission models of pulsars. The high discovery rate of this survey, despite the increasing difficulty of blind pulsar searches in gamma rays, suggests that new systematic surveys such as presented in this article should be continued when new LAT source catalogs become available.

DEEP SPITZER OBSERVATIONS OF INFRARED-FAINT RADIO SOURCES: HIGH-REDSHIFT RADIO-LOUD ACTIVE GALACTIC NUCLEI?

International Nuclear Information System (INIS)

Norris, Ray P.; Mao, Minnie; Afonso, Jose; Cava, Antonio; Farrah, Duncan; Oliver, Seb; Huynh, Minh T.; Mauduit, Jean-Christophe; Surace, Jason; Ivison, R. J.; Jarvis, Matt; Lacy, Mark; Maraston, Claudia; Middelberg, Enno; Seymour, Nick

2011-01-01

Infrared-faint radio sources (IFRSs) are a rare class of objects which are relatively bright at radio wavelengths but very faint at infrared and optical wavelengths. Here we present sensitive near-infrared observations of a sample of these sources taken as part of the Spitzer Extragalactic Representative Volume Survey. Nearly all the IFRSs are undetected at a level of ∼1 μJy in these new deep observations, and even the detections are consistent with confusion with unrelated galaxies. A stacked image implies that the median flux density is S 3.6μm ∼ 0.2 μJy or less, giving extreme values of the radio-infrared flux density ratio. Comparison of these objects with known classes of object suggests that the majority are probably high-redshift radio-loud galaxies, possibly suffering from significant dust extinction.

Single-stage plasma-based correlated energy spread compensation for ultrahigh 6D brightness electron beams

Science.gov (United States)

Manahan, G. G.; Habib, A. F.; Scherkl, P.; Delinikolas, P.; Beaton, A.; Knetsch, A.; Karger, O.; Wittig, G.; Heinemann, T.; Sheng, Z. M.; Cary, J. R.; Bruhwiler, D. L.; Rosenzweig, J. B.; Hidding, B.

2017-06-01

Plasma photocathode wakefield acceleration combines energy gains of tens of GeV m-1 with generation of ultralow emittance electron bunches, and opens a path towards 5D-brightness orders of magnitude larger than state-of-the-art. This holds great promise for compact accelerator building blocks and advanced light sources. However, an intrinsic by-product of the enormous electric field gradients inherent to plasma accelerators is substantial correlated energy spread--an obstacle for key applications such as free-electron-lasers. Here we show that by releasing an additional tailored escort electron beam at a later phase of the acceleration, when the witness bunch is relativistically stable, the plasma wave can be locally overloaded without compromising the witness bunch normalized emittance. This reverses the effective accelerating gradient, and counter-rotates the accumulated negative longitudinal phase space chirp of the witness bunch. Thereby, the energy spread is reduced by an order of magnitude, thus enabling the production of ultrahigh 6D-brightness beams.

Core or Cusps: The Central Dark Matter Profile of a Strong Lensing Cluster with a Bright Central Image at Redshift 1

Energy Technology Data Exchange (ETDEWEB)

Collett, Thomas E.; Buckley-Geer, Elizabeth; Lin, Huan; Bacon, David; Nichol, Robert C.; Nord, Brian; Morice-Atkinson, Xan; Amara, Adam; Birrer, Simon; Kuropatkin, Nikolay; More, Anupreeta; Papovich, Casey; Romer, Kathy K.; Tessore, Nicolas; Abbott, Tim M. C.; Allam, Sahar; Annis, James; Benoit-Lévy, Aurlien; Brooks, David; Burke, David L.; Carrasco Kind, Matias; Castander, Francisco Javier J.; D’Andrea, Chris B.; da Costa, Luiz N.; Desai, Shantanu; Diehl, H. Thomas; Doel, Peter; Eifler, Tim F.; Flaugher, Brenna; Frieman, Josh; Gerdes, David W.; Goldstein, Daniel A.; Gruen, Daniel; Gschwend, Julia; Gutierrez, Gaston; James, David J.; Kuehn, Kyler; Kuhlmann, Steve; Lahav, Ofer; Li, Ting S.; Lima, Marcos; Maia, Marcio A. G.; March, Marisa; Marshall, Jennifer L.; Martini, Paul; Melchior, Peter; Miquel, Ramon; Plazas, Andrs A.; Rykoff, Eli S.; Sanchez, Eusebio; Scarpine, Vic; Schindler, Rafe; Schubnell, Michael; Sevilla-Noarbe, Ignacio; Smith, Mathew; Sobreira, Flavia; Suchyta, Eric; Swanson, Molly E. C.; Tarle, Gregory; Tucker, Douglas L.; Walker, Alistair R.

2017-07-10

We report on SPT-CLJ2011-5228, a giant system of arcs created by a cluster at $z=1.06$. The arc system is notable for the presence of a bright central image. The source is a Lyman Break galaxy at $z_s=2.39$ and the mass enclosed within the 14 arc second radius Einstein ring is $10^{14.2}$ solar masses. We perform a full light profile reconstruction of the lensed images to precisely infer the parameters of the mass distribution. The brightness of the central image demands that the central total density profile of the lens be shallow. By fitting the dark matter as a generalized Navarro-Frenk-White profile---with a free parameter for the inner density slope---we find that the break radius is $270^{+48}_{-76}$ kpc, and that the inner density falls with radius to the power $-0.38\\pm0.04$ at 68 percent confidence. Such a shallow profile is in strong tension with our understanding of relaxed cold dark matter halos; dark matter only simulations predict the inner density should fall as $r^{-1}$. The tension can be alleviated if this cluster is in fact a merger; a two halo model can also reconstruct the data, with both clumps (density going as $r^{-0.8}$ and $r^{-1.0}$) much more consistent with predictions from dark matter only simulations. At the resolution of our Dark Energy Survey imaging, we are unable to choose between these two models, but we make predictions for forthcoming Hubble Space Telescope imaging that will decisively distinguish between them.

Bright galaxies in the Fornax cluster. Automated galaxy surface photometry: Pt. 7

International Nuclear Information System (INIS)

Disney, M.J.; Phillipps, S.; Davies, J.L.; Cawson, M.G.M.; Kibblewhite, E.J.

1990-01-01

We have determined surface-brightness profiles for all galaxies down to magnitude B = 16 in the central region of the Fornax cluster. Using existing redshift data, we have determined the distributions of surface brightness for both the whole sample and for cluster disc galaxies only. Although both distributions peak at extrapolated central surface brightness ∼ 21.7B mag/arcsec 2 (the canonical result), it is shown that they are, in fact, consistent with very broad distributions of disc central surface brightness once selection effects and the effects of bulge contamination of the profile are taken into account. (author)

The potential use of diamond coated tungsten tips as a field ionisation source

Energy Technology Data Exchange (ETDEWEB)

Brown, A.; Prawer, S.; Legge, G.J.F.; Kostidis, L.I. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1996-12-31

Tungsten tips are convenient for use in a high brightness gaseous phase field ionisation source. However, the lifetime of these tips is not adequate for practical use. The authors are investigating whether coating tungsten tips with diamond using Chemical Vapor Deposition (CVD) will improve the practicality of using these tips by an improvement in longevity of the source and/or an improvement in brightness due to the effects of the property of negative electron affinity which has been observed on CVD diamond. 1 ref.

The potential use of diamond coated tungsten tips as a field ionisation source

Energy Technology Data Exchange (ETDEWEB)

Brown, A; Prawer, S; Legge, G J.F.; Kostidis, L I [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1997-12-31

Tungsten tips are convenient for use in a high brightness gaseous phase field ionisation source. However, the lifetime of these tips is not adequate for practical use. The authors are investigating whether coating tungsten tips with diamond using Chemical Vapor Deposition (CVD) will improve the practicality of using these tips by an improvement in longevity of the source and/or an improvement in brightness due to the effects of the property of negative electron affinity which has been observed on CVD diamond. 1 ref.

The NuSTAR  Extragalactic Surveys: X-Ray Spectroscopic Analysis of the Bright Hard-band Selected Sample

Science.gov (United States)

Zappacosta, L.; Comastri, A.; Civano, F.; Puccetti, S.; Fiore, F.; Aird, J.; Del Moro, A.; Lansbury, G. B.; Lanzuisi, G.; Goulding, A.; Mullaney, J. R.; Stern, D.; Ajello, M.; Alexander, D. M.; Ballantyne, D. R.; Bauer, F. E.; Brandt, W. N.; Chen, C.-T. J.; Farrah, D.; Harrison, F. A.; Gandhi, P.; Lanz, L.; Masini, A.; Marchesi, S.; Ricci, C.; Treister, E.

2018-02-01

We discuss the spectral analysis of a sample of 63 active galactic nuclei (AGN) detected above a limiting flux of S(8{--}24 {keV})=7× {10}-14 {erg} {{{s}}}-1 {{cm}}-2 in the multi-tiered NuSTAR extragalactic survey program. The sources span a redshift range z=0{--}2.1 (median =0.58). The spectral analysis is performed over the broad 0.5–24 keV energy range, combining NuSTAR with Chandra and/or XMM-Newton data and employing empirical and physically motivated models. This constitutes the largest sample of AGN selected at > 10 {keV} to be homogeneously spectrally analyzed at these flux levels. We study the distribution of spectral parameters such as photon index, column density ({N}{{H}}), reflection parameter ({\\boldsymbol{R}}), and 10–40 keV luminosity ({L}{{X}}). Heavily obscured ({log}[{N}{{H}}/{{cm}}-2]≥slant 23) and Compton-thick (CT; {log}[{N}{{H}}/{{cm}}-2]≥slant 24) AGN constitute ∼25% (15–17 sources) and ∼2–3% (1–2 sources) of the sample, respectively. The observed {N}{{H}} distribution agrees fairly well with predictions of cosmic X-ray background population-synthesis models (CXBPSM). We estimate the intrinsic fraction of AGN as a function of {N}{{H}}, accounting for the bias against obscured AGN in a flux-selected sample. The fraction of CT AGN relative to {log}[{N}{{H}}/{{cm}}-2]=20{--}24 AGN is poorly constrained, formally in the range 2–56% (90% upper limit of 66%). We derived a fraction (f abs) of obscured AGN ({log}[{N}{{H}}/{{cm}}-2]=22{--}24) as a function of {L}{{X}} in agreement with CXBPSM and previous zvalues.

XMM-Newton 13H deep field - I. X-ray sources

Science.gov (United States)

Loaring, N. S.; Dwelly, T.; Page, M. J.; Mason, K.; McHardy, I.; Gunn, K.; Moss, D.; Seymour, N.; Newsam, A. M.; Takata, T.; Sekguchi, K.; Sasseen, T.; Cordova, F.

2005-10-01

We present the results of a deep X-ray survey conducted with XMM-Newton, centred on the UK ROSAT13H deep field area. This region covers 0.18 deg2, and is the first of the two areas covered with XMM-Newton as part of an extensive multiwavelength survey designed to study the nature and evolution of the faint X-ray source population. We have produced detailed Monte Carlo simulations to obtain a quantitative characterization of the source detection procedure and to assess the reliability of the resultant sourcelist. We use the simulations to establish a likelihood threshold, above which we expect less than seven (3 per cent) of our sources to be spurious. We present the final catalogue of 225 sources. Within the central 9 arcmin, 68 per cent of source positions are accurate to 2 arcsec, making optical follow-up relatively straightforward. We construct the N(>S) relation in four energy bands: 0.2-0.5, 0.5-2, 2-5 and 5-10 keV. In all but our highest energy band we find that the source counts can be represented by a double power law with a bright-end slope consistent with the Euclidean case and a break around 10-14yergcm-2s-1. Below this flux, the counts exhibit a flattening. Our source counts reach densities of 700, 1300, 900 and 300 deg-2 at fluxes of 4.1 × 10-16,4.5 × 10-16,1.1 × 10-15 and 5.3 × 10-15ergcm-2s-1 in the 0.2-0.5, 0.5-2, 2-5 and 5-10 keV energy bands, respectively. We have compared our source counts with those in the two Chandra deep fields and Lockman hole, and found our source counts to be amongst the highest of these fields in all energy bands. We resolve >51 per cent (>50 per cent) of the X-ray background emission in the 1-2 keV (2-5 keV) energy bands.

Search for bright stars with infrared excess

Energy Technology Data Exchange (ETDEWEB)

Raharto, Moedji, E-mail: moedji@as.itb.ac.id [Astronomy Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

2014-03-24

Bright stars, stars with visual magnitude smaller than 6.5, can be studied using small telescope. In general, if stars are assumed as black body radiator, then the color in infrared (IR) region is usually equal to zero. Infrared data from IRAS observations at 12 and 25μm (micron) with good flux quality are used to search for bright stars (from Bright Stars Catalogues) with infrared excess. In magnitude scale, stars with IR excess is defined as stars with IR color m{sub 12}−m{sub 25}>0; where m{sub 12}−m{sub 25} = −2.5log(F{sub 12}/F{sub 25})+1.56, where F{sub 12} and F{sub 25} are flux density in Jansky at 12 and 25μm, respectively. Stars with similar spectral type are expected to have similar color. The existence of infrared excess in the same spectral type indicates the existence of circum-stellar dust, the origin of which is probably due to the remnant of pre main-sequence evolution during star formation or post AGB evolution or due to physical process such as the rotation of those stars.

The high brightness temperature of B0529+483 revealed by RadioAstron and implications for interstellar scattering

Science.gov (United States)

Pilipenko, S. V.; Kovalev, Y. Y.; Andrianov, A. S.; Bach, U.; Buttaccio, S.; Cassaro, P.; Cimò, G.; Edwards, P. G.; Gawroński, M. P.; Gurvits, L. I.; Hovatta, T.; Jauncey, D. L.; Johnson, M. D.; Kovalev, Yu A.; Kutkin, A. M.; Lisakov, M. M.; Melnikov, A. E.; Orlati, A.; Rudnitskiy, A. G.; Sokolovsky, K. V.; Stanghellini, C.; de Vicente, P.; Voitsik, P. A.; Wolak, P.; Zhekanis, G. V.

2018-03-01

The high brightness temperatures, Tb ≳ 1013 K, detected in several active galactic nuclei by RadioAstron space VLBI observations challenge theoretical limits. Refractive scattering by the interstellar medium may affect such measurements. We quantify the scattering properties and the sub-mas scale source parameters for the quasar B0529+483. Using RadioAstron correlated flux density measurements at 1.7, 4.8, and 22 GHz on projected baselines up to 240 000 km we find two characteristic angular scales in the quasar core, about 100 and 10 μas. Some indications of scattering substructure are found. Very high brightness temperatures, Tb ≥ 1013 K, are estimated at 4.8 and 22 GHz even taking into account the refractive scattering. Our findings suggest a clear dominance of the particle energy density over the magnetic field energy density in the core of this quasar.

THE 31 DEG{sup 2} RELEASE OF THE STRIPE 82 X-RAY SURVEY: THE POINT SOURCE CATALOG

Energy Technology Data Exchange (ETDEWEB)

LaMassa, Stephanie M.; Urry, C. Megan; Ananna, Tonima; Civano, Francesca; Marchesi, Stefano; Pecoraro, Robert [Yale Center for Astronomy and Astrophysics, Physics Department, P.O. Box 208120, New Haven, CT 06520 (United States); Cappelluti, Nico; Comastri, Andrea; Brusa, Marcella [INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Böhringer, Hans; Chon, Gayoung [Max-Planck-Institut für extraterrestrische Physik, D-85748 Garching (Germany); Glikman, Eilat [Department of Physics, Middlebury College, Middlebury, VT 05753 (United States); Richards, Gordon [Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Cardamone, Carie [Department of Math and Science, Wheelock College, 200 Riverway, Boston, MA 02215 (United States); Farrah, Duncan [Department of Physics MC 0435, Virginia Polytechnic Institute and State University, 850 West Campus Drive, Blacksburg, VA 24061 (United States); Gilfanov, Marat [Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Str. 1, Postfach 1317, D-85741 Garching (Germany); Green, Paul [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Komossa, S. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Lira, Paulina [Departamento de Astronomia, Universidad de Chile, Camino del Observatorio 1515, Santiago (Chile); Makler, Martin [Centro Brasileiro de Pesquisas Fisicas, Rua Dr Xavier Sigaud 150, Rio de Janeiro, RJ 22290-180 (Brazil); and others

2016-02-01