Note that this page of links is assembled automatically via software
algorithm and sometimes it gets a little confused. Also, this is certainly NOT a complete list of resources, its just some of the ones that are easy to retrieve online.
Recent Physics-Related News Articles
These links point to recent Physics-related news articles from the popular press and more "physics oriented" sites.
NASA Delays Next Mars Rover Mission (Fri Dec 5 3:27 am)
NASA has pushed back the launching of the Mars Science Laboratory by two years because of lengthening delays and lingering technical issues, officials announced.
Gene Test Shows Spain’s Jewish and Muslim Mix (Fri Dec 5 2:11 am)
A study of genetic signatures has provided new evidence of the mass conversions of Sephardic Jews and Muslims to Catholicism in the 14th and 15th centuries.
As More Eat Meat, a Bid to Cut Emissions (Thu Dec 4 12:13 pm)
Farm emissions are being discussed during international talks on a new treaty to combat global warming.
Skin Deep: New Products Bring Side Effect: Nanophobia (Thu Dec 4 10:06 am)
In a world where there are so many things to be afraid of, add one more to the list - tiny components engineered on the nanoscale that could run amok inside the body.
Panel Seeks Changes in E.P.A. Reviews (Thu Dec 4 1:26 am)
The Environmental Protection Agency must revise its approach to assessing environmental health hazards and other risks, an expert panel is reporting.
Parents Torn Over Fate of Frozen Embryos (Thu Dec 4 2:06 am)
Couples around the country are having difficulty deciding whether to discard or donate extra embryos created by in vitro fertilization.
NASA Delays Next Mars Rover Mission (Thu Dec 4 6:10 pm)
NASA has pushed back the launching of the Mars Science Laboratory by two years because of lengthening delays and lingering technical issues, officials announced.
Study Illuminates Star Explosion From 16th Century (Wed Dec 3 8:20 pm)
A new study confirms that Tycho Brahe saw a common kind of star explosion that involves the explosion of a white dwarf star with a nearby companion in 1572.
Arduous Space Mission in the Homestretch (Fri Nov 28 1:25 am)
The shuttle Endeavour will separate from the International Space Station on Friday and will land as early as Sunday at 1:18 p.m., weather permitting.
NASA Scales Back Flagship Mars Mission (Fri Nov 21 4:41 pm)
NASA has decided to slash the storage bin from the Mars Science Laboratory’s payload in order to try and meet an October 2009 launch deadline.
National Briefing | Science: Spacewalk Goes Well (Fri Nov 21 1:09 am)
The second spacewalk during a mission of the shuttle Endeavour to the International Space Station proceeded without mishap.
Shuttle Departs With Gear for Space Station (Sat Nov 15 4:46 am)
The space shuttle Endeavour lit the skies over Florida to begin a 15-day mission to the International Space Station.
How GPS Units Work (Wed Dec 3 11:00 pm)
This holiday season all kinds of products are coming equipped with GPS receivers to tell consumers exactly where on earth they are. The choices include dashboard navigators for cars, pocket navigators for humans, “golf buddies”...
Turning Back the Cellular Clock: A Farewell to Embryonic Stem Cells? (Mon Dec 1 11:00 pm)
When historians chronicle the stem cell research wars, Shinya Yamanaka will likely go down as a peacemaker. The Japanese scientist has helped send the field on a surprising end run around the moral debate surrounding embryonic stem cells, the...
Triple Helix: Designing a New Molecule of Life (Mon Dec 1 3:00 am)
For all the magnificent diversity of life on this planet, ranging from tiny bacteria to majestic blue whales, from sunshine-harvesting plants to mineral-digesting endoliths miles underground, only one kind of “life...
Nanomachines Powered by Light (Wed Nov 26 3:35 pm)
Solar power is great for converting light energy into electricity. But what about harnessing light energy directly? After all, photons--discrete packets of light energy--exert force themselves, albeit on a pretty small scale. [More] ...
Procrastination--And Other Stories from MIND (Tue Nov 25 11:00 pm)
Oof. It was yet another “gotcha” moment for me working here at Scientific American Mind. Walking home from the train a few days ago, I was running through my mental to-do list. I realized that, yet again, I somehow had not gotten...
Electronics with a Twist (Mon Nov 24 11:05 pm)
[The following is an exact transcript of this podcast.]Electronics come in all shapes and sizes--but there’s been a limit on their flexibility. Now, researchers say they’ve created electronics that can be shaped in virtually any...
Patternicity: Finding Meaningful Patterns in Meaningless Noise (Mon Nov 24 11:00 pm)
Why do people see faces in nature, interpret window stains as human figures, hear voices in random sounds generated by electronic devices or find conspiracies in the daily news? A proximate cause is the priming effect, in which our brain and...
Magic and the Brain: How Magicians "Trick" the Mind (Mon Nov 24 9:00 am)
The spotlight shines on the magician’s assistant. The woman in the tiny white dress is a luminous beacon of beauty radiating from the stage to the audience. The Great Tomsoni announces he will change her dress from white to red. On the...
After the Crash: How Software Models Doomed the Markets (Thu Nov 20 11:00 pm)
If Hollywood makes a movie about the worst financial crisis since the Great Depression, a basement room in a government building in Washington will serve as the setting for a key scene. There investment bankers from the...
Yahoo Internet search exec defects to Microsoft (Thu Dec 4 4:56 pm)
Microsoft on Thursday announced it has lured an Internet search executive from Yahoo to become head of its online services group.
Review: MiBook is cheap, colorful e-book reader (Thu Dec 4 4:55 pm)
(AP) -- Electronic books are the persistent wallflowers of the gadget world. Consumers have snubbed them again and again in favor of a 500-year-old technology: ink printed on paper.
Gene packaging tells story of cancer development (Thu Dec 4 4:06 pm)
To decipher how cancer develops, Johns Hopkins Kimmel Cancer Center investigators say researchers must take a closer look at the packaging.
Researchers solve piece of large-scale gene silencing mystery (Thu Dec 4 4:05 pm)
A team led by Craig Pikaard, Ph.D., WUSTL professor of biology in Arts & Sciences, has made a breakthrough in understanding the phenomenon of nucleolar dominance, the silencing of an entire parental set of ribosomal RNA genes in a hybrid plant...
Smartphone sales slow down in third quarter (Thu Dec 4 3:51 pm)
Worldwide smartphone sales grew by 11.5 percent in the third quarter of the year, the lowest rate of growth ever recorded for the devices, research company Gartner reported on Thursday.
More shoppers bought online Monday but spent less (Thu Dec 4 3:50 pm)
(AP) -- Online spending at U.S. retailers on Monday jumped 15 percent over with the comparable day a year ago to $846 million, comScore said Thursday, as consumers sought out bargains in a tough economy.
Mix of taiji, cognitive therapy and support groups benefits those with dementia (Thu Dec 4 3:50 pm)
Those diagnosed with early stage dementia can slow their physical, mental and psychological decline by taking part in therapeutic programs that combine counseling, support groups, Taiji and qigong, researchers report. Some of the benefits of...
It's time to make sure all children have health care (Thu Dec 4 2:56 pm)
The current economic downturn has many faces, including those of children. Economic indicators show that the worst of the recession may be yet to come and many economists are predicting that the unemployment rate will rise to as much as 9 percent...
Probing Question: Did Shakespeare really write all those plays? (Thu Dec 4 2:35 pm)
Done to death by slanderous tongues. So wrote William Shakespeare in his play, Much Ado About Nothing. Or did he? Even people who have never actually read Shakespeare have heard the theories: Shakespeare`s plays were written by Francis...
Environmental consequences of nuclear war (Mon Dec 1 7:00 am)
A regional war involving 100 Hiroshima-sized weapons would pose a worldwide threat due to ozone destruction
and climate change. A superpower confrontation with a few thousand weapons would be catastrophic.
Batteries and electrochemical capacitors (Mon Dec 1 7:00 am)
Present and future applications of electrical energy storage devices are stimulating research into
innovative new materials and novel architectures
Who is listening? What do they hear? (Mon Dec 1 7:00 am)
In communicating our science, have we put too much emphasis on the information we want to convey?
Perhaps there is another way to think about it
Physics Nobel Prize to Nambu, Kobayashi, and Maskawa (Mon Dec 1 7:00 am)
In particle physics, some symmetries are so severely broken that
they?re hard to recognize. Others are so slightly broken that the
imperfection is hard to find.
Japan aims to internationalize its science enterprise (Mon Dec 1 7:00 am)
Money and bows to other cultures, such as merit-based salaries and English
in the lab, are cultivating good science and attracting leading scientists to
spend time in Japan.
One of the things that sets science apart from many other fields of human-endeavor is that to prevent personal opinion from being represented as fact, articles that are submitted to scientific journals are "peer-reviewed", which means the paper is sent to a referee (possibly a scientific "competitor") who disects the article and makes sure its conclusions are valid based on the data presented. The process is not perfect, but it tends to drive a high level of scholarly quality in peer-reviewed journals.
USAGE NOTE: The symbol next to each feed item can be clicked in order to bring up the abstract from the article.
Author(s): Alejandro Cuetos, Amparo Galindo, and George JacksonWe present the first examples of thermotropic biaxial mesophases in mixtures of model attractive uniaxial molecules. Nematic and smectic biaxial phases are identified. The nematic biaxial phase has remained a key challenge in the science of liquid crystals since it was first proposed almost 40 years...[Phys. Rev. Lett. 101, 237802] Published Thu Dec 04, 2008
Author(s): Mojca Vilfan, Natan Osterman, Martin Čopič, Miha Ravnik, Slobodan Žumer, Jurij Kotar, Dušan Babič, and Igor PoberajWe studied the confinement effect on the interaction force in nematic liquid crystal colloids with spherical particles inducing planar anchoring. Using magneto-optical tweezers, we measured the spatial dependence of the quadrupolar structural interparticle force over 4 orders of magnitude. For smal...[Phys. Rev. Lett. 101, 237801] Published Thu Dec 04, 2008
Author(s): Shinya Kasai, Peter Fischer, Mi-Young Im, Keisuke Yamada, Yoshinobu Nakatani, Kensuke Kobayashi, Hiroshi Kohno, and Teruo OnoTime-resolved soft x-ray transmission microscopy is applied to image the current-induced resonant dynamics of the magnetic vortex core realized in a micron sized Permalloy disk. The high spatial resolution better than 25 nm enables us to observe the resonant motion of the vortex core. The result al...[Phys. Rev. Lett. 101, 237203] Published Thu Dec 04, 2008
Author(s): M. Daghofer, A. Moreo, J. A. Riera, E. Arrigoni, D. J. Scalapino, and E. DagottoA two-orbital model for Fe-pnictide superconductors is investigated using computational techniques on two-dimensional square clusters. The hopping amplitudes are derived from orbital overlap integrals, or by band structure fits, and the spin frustrating effect of the plaquette-diagonal Fe-Fe hopping...[Phys. Rev. Lett. 101, 237004] Published Thu Dec 04, 2008
Author(s): G. Fuchs, S.-L. Drechsler, N. Kozlova, G. Behr, A. K?r, J. Werner, K. Nenkov, R. Klingeler, J. Hamann-Borrero, C. Hess, A. Kondrat, M. Grobosch, A. Narduzzo, M. Knupfer, J. Freudenberger, B. B?er, and L. SchultzWe report upper critical field B_{c2} (T) data for disordered (arsenic-deficient) LaO_{0.9} F_{0.1} FeAs_{1-δ} in a wide temperature and magnetic field range up to 47 T. Because of the large linear slope of B_{c2} ≈-5.4 to -6.6 T/K near T_{c} ≈28.5 K, the T dependence of the in-plane...[Phys. Rev. Lett. 101, 237003] Published Thu Dec 04, 2008
Author(s): F. J. Wang, Heinz B?ler, and Z. Valy VardenyWe studied magnetoconductance (MC) and magnetoelectroluminescence (MEL) in organic diodes from blends of π-conjugated polymers and fullerenes at various concentrations, c. The MC response is composed of several components that depend on the applied bias voltage and c. A dominant positive low-field ...[Phys. Rev. Lett. 101, 236805] Published Thu Dec 04, 2008
Author(s): D. J. Reilly, J. M. Taylor, E. A. Laird, J. R. Petta, C. M. Marcus, M. P. Hanson, and A. C. GossardIn quantum dots made from materials with nonzero nuclear spins, hyperfine coupling creates a fluctuating effective Zeeman field (Overhauser field) felt by electrons, which can be a dominant source of spin qubit decoherence. We characterize the spectral properties of the fluctuating Overhauser field ...[Phys. Rev. Lett. 101, 236803] Published Thu Dec 04, 2008
Author(s): J. B?ann, F. Gebhard, T. Ohm, S. Weiser, and W. WeberWe use the Gutzwiller variational theory to investigate the electronic and magnetic properties of fcc nickel. Our particular focus is on the effects of the spin-orbit coupling. Unlike standard relativistic band-structure theories, we reproduce the experimental magnetic-moment direction and we explai...[Phys. Rev. Lett. 101, 236404] Published Thu Dec 04, 2008
Author(s): Dong Guo, Kenji Sakamoto, Kazushi Miki, Susumu Ikeda, and Koichiro SaikiWe report the epitaxial growth of thin films of a small organic molecule (pentacene) on polymer substrates with controllable photoalignment over a wide range. The pentacene molecular plane exhibited a distinct orientational change from parallel to perpendicular relative to the polymer chain with inc...[Phys. Rev. Lett. 101, 236103] Published Thu Dec 04, 2008
Author(s): J. D. Lee and Muneaki HaseIn the investigation of the nonequilibrium ultrafast dynamics of the coherent phonon-plasmon coupled modes in a polar semiconductor, we predict theoretically that their coherent oscillations can be efficiently controlled by using the pulse train of below-band-gap excitation. The dynamics of the cohe...[Phys. Rev. Lett. 101, 235501] Published Thu Dec 04, 2008
Author(s): W. F. Bergerson, D. A. Hannum, C. C. Hegna, R. D. Kendrick, J. S. Sarff, and C. B. ForestThe resistive wall mode is experimentally identified and characterized in a line-tied, cylindrical screw pinch when the edge safety factor is less than a critical value. Different wall materials have been used to change the wall time and show that the growth rates for the RWM scale with wall time an...[Phys. Rev. Lett. 101, 235005] Published Thu Dec 04, 2008
Author(s): Hiroki Takahashi, Kentaro Wakui, Shigenari Suzuki, Masahiro Takeoka, Kazuhiro Hayasaka, Akira Furusawa, and Masahide SasakiWe propose and demonstrate a novel method to generate a large-amplitude coherent-state superposition (CSS) via ancilla-assisted photon subtraction. The ancillary mode induces quantum interference of indistinguishable processes in an extended space, widening the controllability of quantum superpositi...[Phys. Rev. Lett. 101, 233605] Published Thu Dec 04, 2008
Author(s): D. F. Ye, X. Liu, and J. LiuWith a semiclassical quasistatic model, we identify the distinct roles of nuclear Coulomb attraction, final-state electron repulsion, and the electron-field interaction in forming the fingerlike (or V-shaped) pattern in the correlated electron momentum distribution for helium double ionization in in...[Phys. Rev. Lett. 101, 233003] Published Thu Dec 04, 2008
Author(s): El Houssine Mezoir and P. Gonz?zWe show that a static central potential may provide a precise description of highly excited light unflavored mesons. Because of string breaking, this potential becomes of chromoelectric type at sufficiently large quark-antiquark distances giving rise to a Coulombian spectrum. The same conclusion can...[Phys. Rev. Lett. 101, 232001] Published Thu Dec 04, 2008
Author(s): Luciano C. Lapas, Rafael Morgado, Mendeli H. Vainstein, J. Miguel Rub?and Fernando A. OliveiraA recent Letter [M. H. Lee, Phys. Rev. Lett. 98, 190601 (2007)] has called attention to the fact that irreversibility is a broader concept than ergodicity, and that therefore the Khinchin theorem [A. I. Khinchin, Mathematical Foundations of Statistical Mechanics (Dover, New York, 1949)] may fail...[Phys. Rev. Lett. 101, 230602] Published Thu Dec 04, 2008
Author(s): Huafeng Ding, Zhuo Wang, Freddy Nguyen, Stephen A. Boppart, and Gabriel PopescuFourier transform light scattering (FTLS) is a novel experimental approach that combines optical microscopy, holography, and light scattering for studying inhomogeneous and dynamic media. In FTLS the optical phase and amplitude of a coherent image field are quantified and propagated numerically to t...[Phys. Rev. Lett. 101, 238102] Published Wed Dec 03, 2008
Author(s): S. J. Green, J. Bath, and A. J. TurberfieldThe second law of thermodynamics requires that directed motion be accompanied by dissipation of energy. Here we demonstrate the working principles of a bipedal molecular motor. The motor is constructed from DNA and is driven by the hybridization of a DNA fuel. We show how the catalytic activities of...[Phys. Rev. Lett. 101, 238101] Published Wed Dec 03, 2008
Author(s): J. Walowski, G. M?r, M. Djordjevic, M. M?nberg, M. Kl?, C. A. Vaz, and J. A. BlandWe relate the energy dissipation processes at the femtosecond (electron-spin relaxation time τ_{el-sp} ) and nanosecond time scale (Gilbert relaxation τ_{α} ) to the microscopic model proposed by Koopmans [Phys. Rev. Lett. 95, 267207 (2005)]. At both time scales, Elliot-Yafet scattering is propos...[Phys. Rev. Lett. 101, 237401] Published Wed Dec 03, 2008
Author(s): F. Weber, A. Kreyssig, L. Pintschovius, R. Heid, W. Reichardt, D. Reznik, O. Stockert, and K. HradilWe show that the superconducting energy gap 2Δ can be directly observed in phonon spectra, as predicted by recent theories. In addition, since each phonon probes the gap on only a small part of the Fermi surface, the gap anisotropy can be studied in detail. Our neutron scattering investigation of t...[Phys. Rev. Lett. 101, 237002] Published Wed Dec 03, 2008
Author(s): J. Sch?r, C. Blumenstein, S. Meyer, M. Wisniewski, and R. ClaessenUnique electronic properties of self-organized Au atom chains on Ge(001) in novel c(8?) long-range order are revealed by scanning tunneling microscopy. Along the nanowires an exceptionally narrow conduction path exists which is virtually decoupled from the substrate. It is laterally confined to th...[Phys. Rev. Lett. 101, 236802] Published Wed Dec 03, 2008
Author(s): Roberto Macovez, Andrea Goldoni, Luca Petaccia, Ingrid Marenne, Paul A. Br?ler, and Petra RudolfThe simple cubic phase of a RbC_{60} thin film has been studied using photoelectron spectroscopy. The simple cubic-to-dimer transition is found to be reversible at the film surface. A sharp Fermi edge is observed and a lower limit of 0.5 eV is found for the surface Hubbard U, pointing to a strong...[Phys. Rev. Lett. 101, 236403] Published Wed Dec 03, 2008
Author(s): R. Saniz, M. R. Norman, and A. J. FreemanA first principles study of La_{2-2x} Sr_{1+2x} Mn_{2} O_{7} compounds for doping levels 0.3≤x≤0.5 shows that the low energy electronic structure of the majority spin carriers is determined by strong momentum-dependent interactions between the Mn e_{g} d_{x^{2} -y^{2} } and d_{3z^{2} -r^{2} } or...[Phys. Rev. Lett. 101, 236402] Published Wed Dec 03, 2008
Author(s): Jean-Luc Blanchet, Fabrice Devaux, Luca Furfaro, and Eric LantzWe have measured sub-shot-noise quantum correlations of spatial fluctuations in the far-field image of the parametric fluorescence created in a type I beta-barium-borate nonlinear crystal. Imaging is performed at very low light level (0.15 photons per pixel) with an electron multiplying charge coup...[Phys. Rev. Lett. 101, 233604] Published Wed Dec 03, 2008
Author(s): L. A. Surin, A. V. Potapov, B. S. Dumesh, S. Schlemmer, Y. Xu, P. L. Raston, and W. J?rHigh resolution microwave and millimeter-wave spectra of He_{N} -CO clusters with N up to 10, produced in a molecular expansion, were observed. Two series of J=1–0 transitions were detected, which correspond to the a-type and b-type J=1–0 transitions of He_{1} -CO. The B rotational constant init...[Phys. Rev. Lett. 101, 233401] Published Wed Dec 03, 2008
Author(s): A. Adare et al. PHENIX CollaborationFor Au+Au collisions at 200 GeV, we measure neutral pion production with good statistics for transverse momentum, p_{T} , up to 20 GeV/c. A fivefold suppression is found, which is essentially constant for 5
Author(s): Y. Nambu and G. Jona-LasinioContinuing the program developed in a previous paper, a "superconductive" solution describing the proton-neutron doublet is obtained from a nonlinear spinor field Lagrangian. We find the pions of finite mass as nucleon-antinucleon bound states by introducing a small bare mass into the Lagrangian whi...[Phys. Rev. 124, 246] Published Sun Oct 01, 1961
Author(s): Y. Nambu and G. Jona-LasinioIt is suggested that the nucleon mass arises largely as a self-energy of some primary fermion field through the same mechanism as the appearance of energy gap in the theory of superconductivity. The idea can be put into a mathematical formulation utilizing a generalized Hartree-Fock approximation wh...[Phys. Rev. 122, 345] Published Sat Apr 01, 1961
Author(s): Shun Watanabe, Ryutaroh Matsumoto, and Tomohiko UyematsuWe construct a practically implementable classical processing for the Bennett-Brassard 1984 (BB84) protocol and the six-state protocol that fully utilizes the accurate channel estimation method, which is also known as the quantum tomography. Our proposed processing yields at least as high a key rate...[Phys. Rev. A 78, 042316] Published Fri Oct 17, 2008
Author(s): Christian Carbogno, J?Behler, Axel Gro? and Karsten ReuterWe perform mixed quantum-classical molecular dynamics simulations based on first-principles potential-energy surfaces to demonstrate that the scattering of a beam of singlet O_{2} molecules at Al(111) will enable an unambiguous assessment of the role of spin-selection rules for the adsorption dynami...[Phys. Rev. Lett. 101, 096104] Published Fri Aug 29, 2008
Author(s): Qing-Miao Hu, Karsten Reuter, and Matthias SchefflerIt is shown that the errors of present-day exchange-correlation (XC) functionals are rather short ranged. For extended systems, the correction can therefore be evaluated by analyzing properly chosen clusters and employing highest-quality quantum chemistry methods. The XC correction rapidly approache...[Phys. Rev. Lett. 98, 176103] Published Mon Apr 23, 2007
Author(s): Hua Wu, Peter Kratzer, and Matthias SchefflerUsing density-functional theory within the generalized gradient approximation, we show that Si-based heterostructures with 1/4 layer δ doping of interstitial Mn (Mn_{int} ) are half-metallic. For Mn_{int} concentrations of 1/2 or 1 layer, the states induced in the band gap of δ-doped heterostruct...[Phys. Rev. Lett. 98, 117202] Published Mon Mar 12, 2007
Author(s): Abhishek Kumar Singh, Anderson Janotti, Matthias Scheffler, and Chris G. Van de WalleSnO_{2} is widely used as a transparent conductor and sensor material. Better understanding and control of its conductivity would enhance its performance in existing applications and enable new ones, such as in light emitters. Using density functional theory, we show that the conventional attributio...[Phys. Rev. Lett. 101, 055502] Published Thu Jul 31, 2008
Author(s): Simone Piccinin, Catherine Stampfl, and Matthias SchefflerIn this paper, we investigate by means of first-principles density functional theory calculations the (111) surface of the Ag-Cu alloy under varying conditions of pressure of the surrounding oxygen atmosphere and temperature. This alloy has been recently proposed as a catalyst with improved selectiv...[Phys. Rev. B 77, 075426] Published Tue Feb 26, 2008
Author(s): Ricardo G?-Abal, Xinzheng Li, Matthias Scheffler, and Claudia Ambrosch-DraxlState-of-the-art theory addresses single-electron excitations in condensed matter by linking density-functional theory (DFT) with many-body perturbation theory. In actual calculations it is common to employ the pseudopotential (PP) approach, where pseudo-wave-functions enter the calculation of the s...[Phys. Rev. Lett. 101, 106404] Published Thu Sep 04, 2008
Author(s): K. S. Hirata et al.Neutrinos from the decay of ^{8} B in the Sun have been observed in the Kamiokande-II detector. Based on 450 days of data in the time period January 1987 through May 1988; the measured flux obtained from data with E_{e} ≥9.3 MeV is 0.46±0.13(stat)±0.08(sys) of the value predicted by the standard...[Phys. Rev. Lett. 63, 16] Published Mon Jul 03, 1989
Author(s): R. M. Bionta et al.A burst of eight neutrino events preceding the optical detection of the supernova in the Large Magellanic cloud has been observed in a large underground water Cherenkov detector. The events span an interval of six seconds and have visible energies in the range 20–40 MeV.[Phys. Rev. Lett. 58, 1494] Published Mon Apr 06, 1987
Author(s): Raymond DavisTanks containing 200 and 3900 liters of carbon tetrachloride were irradiated outside of the shield of the Brookhaven reactor in an attempt to induce the reaction Cl^{37} (ν [over ¯] , e^{-} )A^{37} with fission product antineutrinos. The experiments serve to place an upper limit on the antineutri...[Phys. Rev. 97, 766] Published Tue Feb 01, 1955
Author(s): P. Del’Haye, O. Arcizet, A. Schliesser, R. Holzwarth, and T. J. KippenbergWe demonstrate control and stabilization of an optical frequency comb generated by four-wave mixing in a monolithic microresonator with a mode spacing in the microwave regime (86 GHz). The comb parameters (mode spacing and offset frequency) are controlled via the power and the frequency of the pump...[Phys. Rev. Lett. 101, 053903] Published Thu Jul 31, 2008
Author(s): R. P. MacDonald et al. TWIST CollaborationThe TWIST Collaboration has performed new measurements of two of the parameters that describe muon decay: ρ, which governs the shape of the overall momentum spectrum, and δ, which governs the momentum dependence of the parity-violating decay asymmetry. This analysis gives the results ρ=0.750 14...[Phys. Rev. D 78, 032010] Published Fri Aug 15, 2008
Min-Hyong Lee and Seong Wook Choi We investigated the evolution of the electron energy distribution function (EEDF) in a solenoidal inductively coupled plasma surrounded by an axial dc magnetic field. The increase in the dc magnetic field caused the EEDF to evolve from a bi-Maxwellian to a Maxwellian distribution. At the discharge c ... [J. Appl. Phys. 104, 113303 (2008)] published Thu Dec 4, 2008.
W. J. Lu, X. Luo, C. Y. Hao, W. H. Song, and Y. P. Sun The effect of grain size on electrical and magnetic properties of LaSrMnO nanoparticles with average grain size 3285 nm has been investigated. The metal-insulator transition temperature T gradually decreases with decreasing grain size, while the ferromagnetic-paramagnetic transition temperature T re ... [J. Appl. Phys. 104, 113908 (2008)] published Thu Dec 4, 2008.
G. Pozina, C. Hemmingsson, U. Forsberg, A. Lundskog, A. Kakanakova-Georgieva et al. AlGaN/AlN/GaN high electron mobility transistor heterostructures grown by metal-organic chemical vapor deposition have been studied by temperature dependent time-resolved photoluminescence. The AlGaN-related emission is found to be sensitive to the excitation power and to the built-in internal elect ... [J. Appl. Phys. 104, 113513 (2008)] published Thu Dec 4, 2008.
Daniel Aronov and Michel Molotskii We investigate a wettability modification of ultrathin dielectric films induced by an electron irradiation. The effect of wettability inversion, transition from hydrophobic to hydrophilic state, is predicted for low irradiation doses. It is supposed that the inversion is caused by a change in the ba ... [J. Appl. Phys. 104, 114903 (2008)] published Thu Dec 4, 2008.
P. R. Ohodnicki, J. Long, D. E. Laughlin, M. E. McHenry, V. Keylin et al. The composition dependence of field induced anisotropy K of field annealed soft ferromagnetic (CoFe)ZrB and (CoFe)ZrBCu amorphous and amorphous/nanocrystalline nanocomposite melt spun ribbons is investigated. With the exception of the highest Co-containing alloys (x
M. Ryzhii, A. Satou, V. Ryzhii, and T. Otsuji We propose an analytical device model for a graphene nanoribbon field-effect transistor (GNR-FET) under the dc and ac operating conditions. The GNR-FET under consideration is based on a heterostructure, which consists of an array of nanoribbons clad between the highly conducting substrate (the back ... [J. Appl. Phys. 104, 114505 (2008)] published Thu Dec 4, 2008.
V. M. Petrov, G. Srinivasan, and T. A. Galkina A model is discussed for magnetoelectric interactions under ferromagnetic resonance (FMR) in bilayers of a ferrite and a functionally graded piezoelectric. A linear variation in the in-plane piezoelectric coefficient is assumed. A dc electric field E applied perpendicular to the sample plane will th ... [J. Appl. Phys. 104, 113910 (2008)] published Thu Dec 4, 2008.
John G. Hartnett, David Mouneyrac, Jean-Michel Le Floch, Jerzy Krupka, Michael E. Tobar et al. Whispering gallery modes in bulk cylindrical gallium arsenide and gallium phosphide samples have been examined both in darkness and under white light at cryogenics temperatures
L. Vincent, L. Thome, F. Garrido, O. Kaitasov, and F. Houdelier The aim of this study was to identify experimentally the phase which includes cesium in yttria stabilized zirconia (YSZ). The solubility and retention of cesium in YSZ were studied at high temperature (HT). Cesium was ion implanted (at 300 keV) into YSZ at room temperature (RT), 750 degrees C, or 9 ... [J. Appl. Phys. 104, 114904 (2008)] published Thu Dec 4, 2008.
S. M. Kostritskii, O. G. Sevostyanov, M. Aillerie, and P. Bourson Photorefractive damage (PRD) in as-grown, oxidized, and slightly reduced nominally pure LiNbO, and iron-doped crystals with different compositions has been studied with the closed-aperture Z-scan and pseudo-Z-scan techniques at uniform temperature distribution, as well as at a steady-state temperatu ... [J. Appl. Phys. 104, 114104 (2008)] published Thu Dec 4, 2008.
Doan Nhat Quang, Nguyen Huyen Tung, Do Thi Hien, and Tran Thi Hai We present a theory of the low-temperature transport of holes confined in the Ge strained channel of single-side modulation-doped SiGe/Ge/SiGe square quantum wells (QWs). Besides the well-known scattering mechanisms such as remote impurities and surface roughness, the theory includes misfit deformat ... [J. Appl. Phys. 104, 113711 (2008)] published Thu Dec 4, 2008.
G. Tang, Y.-L. Shen, and N. Chawla The indentation behavior of a heterogeneous material with constituents having distinctly different mechanical properties was studied numerically. The microstructural heterogeneity was represented by an elastic-plastic finite element model featuring explicit metal/ceramic nanolayers. Internal deforma ... [J. Appl. Phys. 104, 116102 (2008)] published Thu Dec 4, 2008.
Shisheng Lin, Haiping He, Zhizhen Ye, Binghui Zhao, and Jingyun Huang The authors report fabrication of aluminum monodoped ZnO (AlZnO) and aluminum-indium dual-doped ZnO (AlInZnO) nanorods arrays. Optical properties of AlZnO and AlInZnO nanorods are studied through temperature-dependent photoluminescence (PL) and PL excitation (PLE). Compared to AlInZnO nanorods, AlZn ... [J. Appl. Phys. 104, 114307 (2008)] published Thu Dec 4, 2008.
Yuankun Lin, Ahmad Harb, Daniel Rodriguez, Karen Lozano, Di Xu et al. This paper reports the experimental approaches to the fabrication of two-layer integrated phase masks and the fabrication of photonic crystal templates using the phase mask based on holographic lithography technique. The photonic crystal template is formed by exposing photoresist mixtures to five-be ... [J. Appl. Phys. 104, 113111 (2008)] published Thu Dec 4, 2008.
Z. Yang, M. Biasini, W. P. Beyermann, M. B. Katz, O. K. Ezekoye et al. Diluted magnetic semiconducting ZnO:Co thin films with above room-temperature T were prepared. Transmission electron microscopy and x-ray diffraction studies indicate the ZnO:Co thin films are free of secondary phases. The magnetization of the ZnO:Co thin films shows a free electron carrier concentr ... [J. Appl. Phys. 104, 113712 (2008)] published Thu Dec 4, 2008.
M. S. Mohamed, T. Yabe, C. Baasandash, Y. Sato, Y. Mori et al. Experiments for laser induced production of magnesium (Mg) from magnesium oxide (MgO) using reducing agents (R) were conducted. In these experiments, continuous wave CO focused laser is focused on a mixture of magnesium oxide and reducing agent. High power density of focused laser leads to high temp ... [J. Appl. Phys. 104, 113110 (2008)] published Thu Dec 4, 2008.
Makoto Suzuki, Kazuhiro Kumagai, Takashi Sekiguchi, Alan M. Cassell, Tsutomu Saito et al. We present secondary electron (SE) emission results from freely supported carbon/silicon nitride (SiN) hybrid nanowires using scanning electron microscopy. We found that, contrary to bulk materials, the SE emission from insulating or electrically isolated metallic nanowires is strongly suppressed by ... [J. Appl. Phys. 104, 114306 (2008)] published Thu Dec 4, 2008.
Liang Zhou, Hongjie Zhang, Weidong Shi, Ruiping Deng, Zhefeng Li et al. In this study, we investigated the dependence of electroluminescence (EL) efficiency on carrier distribution in the light-emitting layer (EML) of the device based on Eu(TTA)phen (TTA=thenoyltrifluoroacetone, phen=1,10-phenanthroline) doped 4,4-N,N-dicarbazole-biphenyl (CBP) system. We found that EL ... [J. Appl. Phys. 104, 114507 (2008)] published Thu Dec 4, 2008.
Sunwook Kim and Seongtae Bae Spatial interactions of the magnetic field produced by an immobilized ferrimagnetic nanoparticle agent on the sensing layer have been numerically calculated considering the longitudinal and transverse components of the magnetic field. Based on the calculations, the sensor geometry to obtain the maxi ... [J. Appl. Phys. 104, 113911 (2008)] published Thu Dec 4, 2008.
A. Yu. Nikiforov, G. S. Cargill, III, S. P. Guo, and M. C. Tamargo Bias voltages applied to ZnCdSe quantum well light emitting diodes (QW-LEDs) affect both the intensity and wavelength of room temperature cathodoluminescence (CL). These effects have been studied experimentally and theoretically to advance understanding of the CL and optoelectronic behavior of these ... [J. Appl. Phys. 104, 114506 (2008)] published Thu Dec 4, 2008.
Litty Irimpan, V. P. N. Nampoori, and P. Radhakrishnan We describe the structure of luminescence spectrum in the visible region in nano-ZnO in colloidal and thin film forms under weak confinement regime by modeling the transition from excited state energy levels of excitons to their ground state. Measurements on nanocrystallites indicate the presence of ... [J. Appl. Phys. 104, 113112 (2008)] published Thu Dec 4, 2008.
Shahid Naeem, Yu Liu, Heng-Yong Nie, W. M. Lau, and Jun Yang Recently, the rapid advances in quantitative biology and polymer science have led to the atomic force microscope (AFM) being extensively employed for single-molecule force spectroscopy. Deflection sensitivity, a critical factor in single molecule force spectroscopy, is changed due to the change in b ... [J. Appl. Phys. 104, 114504 (2008)] published Thu Dec 4, 2008.
Mei-Hsin Chen and Chih-I Wu The properties of thermally evaporated cesium carbonate (CsCO) and its role as electron injection layers in organic light emitting diodes were investigated. According to the ultraviolet photoemission spectra (UPS), the Fermi level of tris-(8-hydroxyquinoline)-aluminum (Alq) after being doped with Cs ... [J. Appl. Phys. 104, 113713 (2008)] published Thu Dec 4, 2008.
A practical evaluation of the multi-scale CLEAN algorithm is presented. The data used in the comparisons are taken from The H I Nearby Galaxy Survey. The implementation of multi-scale CLEAN in the CASA software package is used, although comparisons are made against the very similar multi-resolution CLEAN algorithm implemented in AIPS. Both are compared against the classical CLEAN algorithm (as implemented in AIPS). The results of this comparison show that several of the well-known characteristics and issues of using classical CLEAN are significantly lessened (or eliminated completely) when using the multi-scale CLEAN algorithm. Importantly, multi-scale CLEAN significantly reduces the effects of the clean "bowl" that is caused by missing short-spacings, and the "pedestal" of low-level un-cleaned flux (which affects flux scales and resolution). Multi-scale CLEAN can clean down to the noise level without the divergence suffered by classical CLEAN. We discuss practical applications of the added contrast provided...
We demonstrate in this paper that the velocity widths of the neutral gas in damped Lyalpha (DLA) systems are inconsistent with these systems originating in gas disks of galaxies, similar to those seen in the local universe. We examine the gas kinematics of local galaxies using the high-quality H I 21 cm data from the H I Nearby Galaxies Survey and make a comparison with the velocity profiles measured in the low-ionization metal lines observed in DLAs at high redshifts. The median velocity width of z = 0 H I gas above the DLA column density limit of N H I = 2 ?1020 cm--2 is approximately 30 km s--1, whereas the typical value in DLAs is a factor of 2 higher. We argue that the gas kinematics at higher redshifts are increasingly influenced by gas that is not participating in ordered rotation in cold disks, but is more likely associated with tidal gas related to galaxy interactions or processes such as superwinds and outflows. An analysis of the H I in the local interacting starburst galaxy M 82 shows that the velocity...
We estimate a characteristic timescale for star formation in the spiral arms of disk galaxies, going from atomic hydrogen (H I) to dust-enshrouded massive stars. Drawing on high-resolution H I data from The H I Nearby Galaxy Survey and 24 mum images from the Spitzer Infrared Nearby Galaxies Survey, we measure the average angular offset between the H I and 24 mum emissivity peaks as a function of radius, for a sample of 14 nearby disk galaxies. We model these offsets assuming an instantaneous kinematic pattern speed, Omega p , and a timescale, t H Imap24 mum, for the characteristic time span between the dense H I phase and the formation of massive stars that heat the surrounding dust. Fitting for Omega p and t H Imap24 mum, we find that the radial dependence of the observed angular offset (of the H I and 24 mum emission) is consistent with this simple prescription; the resulting corotation radii of the spiral patterns are typically R cor sime 2.7Rs , consistent with independent estimates. The resulting values...
We present a comprehensive analysis of the relationship between star formation rate surface density, SigmaSFR, and gas surface density, Sigmagas, at sub-kpc resolution in a sample of 18 nearby galaxies. We use high-resolution H I data from The H I Nearby Galaxy Survey, CO data from HERACLES and the BIMA Survey of Nearby Galaxies, 24 mum data from the Spitzer Space Telescope, and UV data from the Galaxy Evolution Explorer. We target seven spiral galaxies and 11 late-type/dwarf galaxies and investigate how the star formation law differs between the H2 dominated centers of spiral galaxies, their H I dominated outskirts and the H I rich late-type/dwarf galaxies. We find that a Schmidt-type power law with index N = 1.0 ± 0.2 relates SigmaSFR and SigmaH2 across our sample of spiral galaxies, i.e., that H2 forms stars at a constant efficiency in spirals. The average molecular gas depletion time is ~2 ?109 years. The range of SigmaH2 over which we measure this relation is ~3-50 M sun pc--2, significantly lower than...
We measure the star formation efficiency (SFE), the star formation rate (SFR) per unit of gas, in 23 nearby galaxies and compare it with expectations from proposed star formation laws and thresholds. We use H I maps from The H I Nearby Galaxy Survey (THINGS) and derive H2 maps of CO measured by HERA CO-Line Extragalactic Survey and Berkeley-Illinois-Maryland Association Survey of Nearby Galaxies. We estimate the SFR by combining Galaxy Evolution Explorer (GALEX) far-ultraviolet maps and the Spitzer Infrared Nearby Galaxies Survey (SINGS) 24 mum maps, infer stellar surface density profiles from SINGS 3.6 mum data, and use kinematics from THINGS. We measure the SFE as a function of the free fall and orbital timescales, midplane gas pressure, stability of the gas disk to collapse (including the effects of stars), the ability of perturbations to grow despite shear, and the ability of a cold phase to form. In spirals, the SFE of H2 alone is nearly constant at (5.25 ± 2.5) ?10--10 yr--1 (equivalent to an H2 depletion...
We present a new method to remove the impact of random and small-scale noncircular motions from H I velocity fields in (dwarf) galaxies in order to better constrain the dark matter properties for these objects. This method extracts the circularly rotating velocity components from the H I data cube and condenses them into a so-called bulk velocity field. We derive high-resolution (~0.2 kpc) rotation curves of IC 2574 and NGC 2366 based on bulk velocity fields derived from The H I Nearby Galaxy Survey obtained at the Very Large Array. We compare the bulk velocity field rotation curves with those derived from the traditional intensity-weighted mean velocity fields and find significant differences. The bulk velocity field rotation curves are significantly less affected by noncircular motions and constrain the dark matter distribution in our galaxies, allowing us to address the discrepancy between the inferred and predicted dark matter distribution in galaxies (the "cusp/core" problem). Spitzer Infrared Nearby Galaxies...
We present harmonic decompositions of the velocity fields of 19 galaxies from The H I Nearby Galaxy Survey (THINGS) which quantify the magnitude of the noncircular motions in these galaxies and yield observational estimates of the elongations of the dark matter halo potentials. Additionally, we present accurate dynamical center positions for these galaxies. We show that the positions of the kinematic and photometric centers of the large majority of the galaxies in our sample are in good agreement. The median absolute amplitude of the noncircular motions, averaged over our sample, is 6.7 km s--1, with ~90% of the galaxies having median noncircular motions of less than ~9 km s--1. As a fraction of the total rotation velocity, this translates into 4.5% on average. The mean elongation of the gravitational potential, after a statistical correction for an unknown viewing angle, is 0.017 ± 0.020, which is consistent with a round potential. Our derived noncircular motions and elongations are smaller than what is needed...
We present rotation curves of 19 galaxies from The H I Nearby Galaxy Survey (THINGS). The high spatial and velocity resolution of THINGS make these the highest quality H I rotation curves available to date for a large sample of nearby galaxies, spanning a wide range of H I masses and luminosities. The high quality of the data allows us to derive the geometric and dynamical parameters using H I data alone. We do not find any declining rotation curves unambiguously associated with a cut-off in the mass distribution out to the last measured point. The rotation curves are combined with 3.6 mum data from the Spitzer Infrared Nearby Galaxies Survey to construct mass models. Our best-fit dynamical disk masses, derived from the rotation curves, are in good agreement with photometric disk masses derived from the 3.6 mum images in combination with stellar population synthesis arguments and two different assumptions for the stellar initial mass function (IMF). We test the cold dark matter (CDM) motivated cusp model, and...
We examine the evolution of an almost-circular Keplerian orbit interacting with unbound perturbers. We calculate the change in eccentricity and angular momentum that results from a single encounter, assuming that the timescale for the interaction is shorter than the orbital period. The orbital perturbations are incorporated into a Boltzmann equation that allows for eccentricity dissipation. We present an analytic solution to the Boltzmann equation that describes the distribution of orbital eccentricity and relative inclination as a function of time. The eccentricity and inclination of the binary do not evolve according to a normal random walk but perform a L? flight. The slope of the mass spectrum of perturbers dictates whether close gravitational scatterings are more important than distant tidal ones. When close scatterings are important, the mass spectrum sets the slope of the eccentricity and inclination distribution functions. We use this general framework to understand the eccentricities of several Kuiper...
We present new optical photometric and spectroscopic observations and K-band spectroscopy of two magnetic interacting binaries: Tau 4 (RXJ0502.8+1624) and SDSS J121209.31+013627.7. Tau 4 shows short-term, highly modulated optical light but no orbital period is firmly detected. K-band spectroscopy shows H and He I emission and reveals a remarkable phase-resolved dataset. We detect clear evidence for cyclotron humps in the K-band implying a magnetic white dwarf with B ~ 7-11 MG and confirming Tau 4 as a magnetic binary. A short self eclipse by the gas stream is evident as the spectrum changes from emission to absorption and back within a few minutes. None of our K-band spectra of Tau 4 appear similar to the previously reported observation. Optical spectroscopy of SDSS J121209.31+013627.7 in 2007 May and June shows Zeeman-split Balmer absorption lines as previously noted in the literature but only weak, sporadic Halpha emission compared to past data. However, stronger Halpha emission returned in 2008 February, looking...
For the spatial three-body problem, the orbital stability of stationary triangular Lagrangian solutions is investigated. To the end of stability analysis, new equations coupling the mutual distances between bodies (mass points) are deduced. A theorem on the orbital instability of stationary triangular solutions related to circular orbits of mass points is proved.
We present the results of an observational study of the efficiency of deep mixing in globular cluster red giants as a function of stellar metallicity. We determine [C/Fe] abundances based on low-resolution spectra taken with the Kast spectrograph on the 3 m Shane telescope at Lick Observatory. Spectra centered on the 4300 ?CH absorption band were taken for 42 bright red giants in 11 Galactic globular clusters ranging in metallicity from M92 ([Fe/H] = --2.29) to NGC 6712 ([Fe/H] = --1.01). Carbon abundances were derived by comparing values of the CH-band strength index S 2(CH) measured from the data with values measured from a large grid of SSG synthetic spectra. Present-day abundances are combined with theoretical calculations of the time since the onset of mixing, which is also a function of stellar metallicity, to calculate the carbon depletion rate across our metallicity range. We find that the carbon depletion rate is twice as high at a metallicity of [Fe/H] = --2.3 than at [Fe/H] = --1.3, which is a result...
Deep images obtained with MegaCam and WIRCam on the Canada-France-Hawaii Telescope are used to probe the stellar content outside of the central star-forming regions of M82. Stars evolving on the asymptotic giant branch (AGB) are traced along the major axis out to projected distances of 12 kpc, which corresponds to 13 disk scale lengths. The numbers of red supergiants (RSGs) and AGB stars normalized to local surface brightness (the "specific frequency" or SF) is constant when R GC > 4 kpc, indicating that RSGs and AGB stars are well mixed throughout the disk. Moreover, the SF of bright AGB stars in the outer disks of M82 and the Sc galaxy NGC 2403 are identical, suggesting that the specific star-formation rates (SFRs) in these galaxies during intermediate epochs were similar. This similarity in stellar content, coupled with the presence of an extended stellar disk, is consistent with M82 having been a late-type disk galaxy prior to interacting with M81. Still, there is a paucity of RSGs in the outer disk of M82...
New photometric observations and their investigation of the W UMa-type binary, BI CVn, are presented. The variations of the orbital period were analyzed based on 12 new determined times of light minimum together with the others compiled from the literature. It is discovered that the period of BI CVn shows a long-term period decrease at a rate of \dot{P}=-1.51(\pm 0.12)\times {10^{-7}} days year--1 while it undergoes a cyclic variation with a period of 27.0 years and an amplitude of 0fd0151. Photometric solutions determined with the Wilson-Devinney method suggest that BI CVn is a contact binary with a degree of contact of 18.0(±1.7)%. The asymmetry of the light curves was interpreted by the presence of dark spots on both components, and absolute parameters were determined by combining the photometric elements with the spectroscopic solutions given by Lu. The observed period decrease can be plausibly explained by a combination of the mass transfer from the primary to the secondary and angular momentum loss via...
We present the results of a search for a young stellar moving group associated with the star HD 141569---a nearby, isolated Herbig AeBe primary member of a 5 ± 3 Myr-old triple star system on the outskirts of the Sco-Cen complex. Our spectroscopic survey identified a population of 21 Li-rich, lsim 30 Myr-old stars within 30° of HD 141569 which possess similar proper motions with the star. The spatial distribution of these Li-rich stars, however, is not suggestive of a moving group associated with the HD 141569 triplet, but rather this sample appears cospatial with Upper Scorpius (US) and Upper Centaurus Lupus (UCL). We apply a modified moving cluster parallax method to compare the kinematics of these youthful stars with those of the US and UCL. Eight new potential members of US and five new potential members of UCL are identified. A substantial moving group with an identifiable nucleus within 15° (~ 30 pc) of HD 141569 is not found in this sample. Evidently, the HD 141569 system formed ~ 5 Myr ago in relative...
Images made with the Very Long Baseline Array (VLBA) have resolved the region in a nearby (z = 0.035) radio galaxy, Pictor A, where the relativistic jet that originates at the nucleus terminates in an interaction with the intergalactic medium, a so-called radio galaxy hot spot. This image provides the highest spatial resolution view of such an object to date, the maximum angular resolution of 23 mas corresponding to a spatial resolution of 16 pc, more than three times better than previous VLBI observations of similar objects. The northwest Pictor A hot spot is resolved into a complex set of compact components, seen to coincide with the bright part of the hot spot imaged at arcsecond-scale resolution with the Very Large Array (VLA). In addition to a comparison with VLA data, we compare our VLBA results with data from the Hubble Space Telescope and Chandra telescopes, as well as new Spitzer data. The presence of pc-scale components in the hot spot, identifying regions containing strong shocks in the fluid flow,...
We present Gemini optical imaging and spectroscopy of the radio source J 133658.3-295105. Thisd source has been suggested to be the core of an FR II radio source with two detected lobes. J 133658.3-295105 and its lobes are aligned with the optical nucleus of M 83 and with three other radio sources at the M 83 bulge outer region. These radio sources are neither supernova remnants nor H II regions. This curious configuration prompted us to try to determine the distance to J 133658.3-295105. We detected Halpha emission redshifted by ≈ 130 km s--1 with respect to an M 83 H II region 2farcs5 east-southeast of the radio source. We do not detect other redshifted emission lines of an optical counterpart down to m i = 22.2 ± 0.8. Two different scenarios are proposed: the radio source is at z >= 2.5, a much larger distance than the previously proposed lower limit z >= 1.0, or the object was ejected by a gravitational recoil event from the M 83 nucleus. This nucleus is undergoing a strong dynamical evolution, judging...
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