Photometric Variability and Rotation in Magnetic White Dwarfs
... to search for spin periods. Approximately 40% of MWDs exhibit photometric modulations as the star rotates due to the effects from a strong magnetic field or star spots. A sample of 77 MWDs is studied to discover periods on timescales of minutes to one week. Well-defined periods are determined in 12 ...
... to search for spin periods. Approximately 40% of MWDs exhibit photometric modulations as the star rotates due to the effects from a strong magnetic field or star spots. A sample of 77 MWDs is studied to discover periods on timescales of minutes to one week. Well-defined periods are determined in 12 ...
Observations of the Magnetic Fields Inside and Outside the
... Is Magnetism a Life form ? The varied manifestations of magnetism have puzzled many people. Some terms used for these magnetic manifestations are: cosmic unrest, organism-like, biological form, and some actions of magnetism are described as: feeding, reproducing, active, altering, etc. "It appear th ...
... Is Magnetism a Life form ? The varied manifestations of magnetism have puzzled many people. Some terms used for these magnetic manifestations are: cosmic unrest, organism-like, biological form, and some actions of magnetism are described as: feeding, reproducing, active, altering, etc. "It appear th ...
Astrophysics of Dust in Cold Clouds
... seen in diffuse interstellar dust. There are, in addition, numerous weaker features in the optical known as the “diffuse interstellar bands”, or DIBs. Figure 4 shows the extinction for 1.5 µm−1 < λ−1 < 1.75 µm−1 , with several conspicuous DIBs present, most notably the DIB at 0.5780 µm. The stronges ...
... seen in diffuse interstellar dust. There are, in addition, numerous weaker features in the optical known as the “diffuse interstellar bands”, or DIBs. Figure 4 shows the extinction for 1.5 µm−1 < λ−1 < 1.75 µm−1 , with several conspicuous DIBs present, most notably the DIB at 0.5780 µm. The stronges ...
Methanol Masers in the NGC6334F Star Forming Region
... transitions to test pumping models and constrain physical conditions. • These models suggest the following physical parameters for the masing region : nH2 = 106 cm-3, Tgas = 30K, Tdust = 150K, beaming factor around 10. • These parameters are all very plausible for young highmass star formation regio ...
... transitions to test pumping models and constrain physical conditions. • These models suggest the following physical parameters for the masing region : nH2 = 106 cm-3, Tgas = 30K, Tdust = 150K, beaming factor around 10. • These parameters are all very plausible for young highmass star formation regio ...
Carnegie Observatories Astrophysics Series, Vol. 4:
... Desert (1994) lists over 154 “certain” DIBs, with another 52 “probable” features. Amazingly, not a single one has yet been positively identified! High resolution spectroscopy of the 5797Å and 6614Å DIBs reveals fine structure that is consistent with rotational bands in a molecule with tens of atoms ...
... Desert (1994) lists over 154 “certain” DIBs, with another 52 “probable” features. Amazingly, not a single one has yet been positively identified! High resolution spectroscopy of the 5797Å and 6614Å DIBs reveals fine structure that is consistent with rotational bands in a molecule with tens of atoms ...
Much of our original knowledge of interstellar dust comes from a
... The dividing line between low and high temperatures is the 'Debye Temperature' which is 200500 K for typical grain material. It is usually indicated by D. Suppose the dust becomes very warm when a photon hits it, so that Td>D. The main contribution to the heat capacity will be the high T compo ...
... The dividing line between low and high temperatures is the 'Debye Temperature' which is 200500 K for typical grain material. It is usually indicated by D. Suppose the dust becomes very warm when a photon hits it, so that Td>D. The main contribution to the heat capacity will be the high T compo ...
IV Interstellar Dust
... 4. Radio continuum emission from rotating grains (both electric and magnetic dipole radiation). This has only recently been discovered as part of the Galactic radio background in recent years, and the explanations are compelling but still tentative. We will be covering all of these topics with great ...
... 4. Radio continuum emission from rotating grains (both electric and magnetic dipole radiation). This has only recently been discovered as part of the Galactic radio background in recent years, and the explanations are compelling but still tentative. We will be covering all of these topics with great ...
Double relics in Abell 2345 and Abell 1240
... the Coma cluster relic, and only recently a temperature gradient has been found near the relic in Abell 548b by Solovyeva et al. (2008). Here, a precise orientation of the cluster merger with respect to the line of sight is inferred, and the projected displacement of the relic from the shock is thus ...
... the Coma cluster relic, and only recently a temperature gradient has been found near the relic in Abell 548b by Solovyeva et al. (2008). Here, a precise orientation of the cluster merger with respect to the line of sight is inferred, and the projected displacement of the relic from the shock is thus ...
Intraday Variability in Quasars and BL LAC Objects
... scattering of the relativistic electrons with the low-energyphotons emitted by them wouldquickly lead to catastrophic cooling and unobserved high X-ray fluxes (Hoyle et al 1966) unless the objects were close by. This led to the suggestion of bulk relativistic motion(Rees 1966, Woltjer 1966). VLBIobs ...
... scattering of the relativistic electrons with the low-energyphotons emitted by them wouldquickly lead to catastrophic cooling and unobserved high X-ray fluxes (Hoyle et al 1966) unless the objects were close by. This led to the suggestion of bulk relativistic motion(Rees 1966, Woltjer 1966). VLBIobs ...
View/Open - NUI Galway
... The division of the original input beam into four output beams, incorporating the different polarisation projections, can be done by many methods, but they mainly fall into three classes, namely: Division Of Time Polarimeters (DOTP) - in which the components of the intensity vector I are determined ...
... The division of the original input beam into four output beams, incorporating the different polarisation projections, can be done by many methods, but they mainly fall into three classes, namely: Division Of Time Polarimeters (DOTP) - in which the components of the intensity vector I are determined ...
PowerPoint Presentation - University of Chicago, Astronomy
... Bolometers as Far-IR Detectors • Bolometers have quantum efficiency 50% from l = 50 mm to 200 mm and no recombination noise. • Progress is being made on multiplexed bolometers; on the verge of seeing ~32×32 arrays. ...
... Bolometers as Far-IR Detectors • Bolometers have quantum efficiency 50% from l = 50 mm to 200 mm and no recombination noise. • Progress is being made on multiplexed bolometers; on the verge of seeing ~32×32 arrays. ...
Probing magnetic fields with Square Kilometre array and its precursors
... deciphering magnetic field structures in these galaxies is very challenging by this method with the existing radio telescopes. As discussed in Beck & Gaensler (2004), an appropriate observing wavelength for detecting large numbers of polarised sources is ∼GHz. This provides a large field of view, wi ...
... deciphering magnetic field structures in these galaxies is very challenging by this method with the existing radio telescopes. As discussed in Beck & Gaensler (2004), an appropriate observing wavelength for detecting large numbers of polarised sources is ∼GHz. This provides a large field of view, wi ...
arXiv:1009.3685
... (a) Four arrays are assembled together to make a focal plane, for a total of 256 polarimeters at 150 GHz. Each detector wafer, stacked with a λ/4 quartz anti-reflection wafer (not visible), is mounted on a gold plated OFHC copper plate using beryllium-copper spring clips fixed near the corners; (b) ...
... (a) Four arrays are assembled together to make a focal plane, for a total of 256 polarimeters at 150 GHz. Each detector wafer, stacked with a λ/4 quartz anti-reflection wafer (not visible), is mounted on a gold plated OFHC copper plate using beryllium-copper spring clips fixed near the corners; (b) ...
Magnetism in Isolated and Binary White Dwarfs
... a magnetic Ðeld of 100È320 MG (Angel, Liebert, & Stockman 1985 ; Greenstein, Henry, & OÏConnell 1985 ; Wickramasinghe & Ferrario 1988). In particular, the 4135 A Minkowski band, thought by some to be of molecular origin, was shown to be the Hb(2s0È4f0) transition shifted some 700 A from its zero-Ð ...
... a magnetic Ðeld of 100È320 MG (Angel, Liebert, & Stockman 1985 ; Greenstein, Henry, & OÏConnell 1985 ; Wickramasinghe & Ferrario 1988). In particular, the 4135 A Minkowski band, thought by some to be of molecular origin, was shown to be the Hb(2s0È4f0) transition shifted some 700 A from its zero-Ð ...
multiwavelength observations of the gamma-ray
... in low flux states. However, blazars are known to spend most of the time in their quiescent state which has so far received very little attention and is therefore very poorly understood. EGRET detected γ -ray blazars almost exclusively in flaring states, and the simultaneously operating X-ray telesc ...
... in low flux states. However, blazars are known to spend most of the time in their quiescent state which has so far received very little attention and is therefore very poorly understood. EGRET detected γ -ray blazars almost exclusively in flaring states, and the simultaneously operating X-ray telesc ...
Can a Fast-Mode EUV Wave Generate a Stationary Front?
... (gray scale), magnetic field (solid lines), and velocity (arrows). As the shock wave expands, it becomes very similar to the piston-driven shock wave straddling over the source active region as numerically simulated by Chen et al. (2002). The two flanks of the shock wave sweep the flux systems in th ...
... (gray scale), magnetic field (solid lines), and velocity (arrows). As the shock wave expands, it becomes very similar to the piston-driven shock wave straddling over the source active region as numerically simulated by Chen et al. (2002). The two flanks of the shock wave sweep the flux systems in th ...
DEPOLARIZATION OF RADIO BURSTS DUE TO REFLECTION OFF
... Suppose the plasma density (or some other plasma parameter) increases smoothly along a specific direction, identified as the z-axis. The equations of the magnetoionic theory are Fouriertransformed in time and in x and y, and reduced to four coupled linear differential equations in z for Ex ; Ey ; Bx ...
... Suppose the plasma density (or some other plasma parameter) increases smoothly along a specific direction, identified as the z-axis. The equations of the magnetoionic theory are Fouriertransformed in time and in x and y, and reduced to four coupled linear differential equations in z for Ex ; Ey ; Bx ...
Dark Matter with Massive Bigravity Theory
... We send MPl → ∞ and m → 0 while keeping Λ3 = (m2 MPl )1/3 constant In the DL limit the gravitational part of the action takes the ghost-free form Galileon terms ...
... We send MPl → ∞ and m → 0 while keeping Λ3 = (m2 MPl )1/3 constant In the DL limit the gravitational part of the action takes the ghost-free form Galileon terms ...
Fundamentals of radio astronomy - Radio Observations of Active
... • orientation of magnetic field 2nd School on Multiwavelength Astronomy, Amsterdam , June 2010 ...
... • orientation of magnetic field 2nd School on Multiwavelength Astronomy, Amsterdam , June 2010 ...
Herbig-Haro jet in the Haro 6–10 system
... another source. The northern infrared companion of Haro 6–10 system can be considered as a probable candidate. This idea is supported also by the abovementioned fact that the H2 shockexcited emission was observed only in the position of the northern companion. Let us discuss this possibility in more ...
... another source. The northern infrared companion of Haro 6–10 system can be considered as a probable candidate. This idea is supported also by the abovementioned fact that the H2 shockexcited emission was observed only in the position of the northern companion. Let us discuss this possibility in more ...
Figures of Merit - Hampton University
... Many searches for axions • The CAST collaboration (e.g., K. Zioutas et al.,PRL 94, 121301 (2005)) looked for axions from the sun and is upgrading • The ADMX collaboration (Kinion, IDM2004) is upgrading its microwave experiment to search for relic axions • PVLAS is upgrading, and running with new ...
... Many searches for axions • The CAST collaboration (e.g., K. Zioutas et al.,PRL 94, 121301 (2005)) looked for axions from the sun and is upgrading • The ADMX collaboration (Kinion, IDM2004) is upgrading its microwave experiment to search for relic axions • PVLAS is upgrading, and running with new ...
The magnetic field of epsilon Eri
... eect causes the lines in the spectrum to be split. The light also becomes polarized. By looking at the circular polarization, we can get information about the longitudinal magnetic eld. We study the polarization proles in the high-resolution spectra of ε Eri, to increase the S/N ratio, the LSD me ...
... eect causes the lines in the spectrum to be split. The light also becomes polarized. By looking at the circular polarization, we can get information about the longitudinal magnetic eld. We study the polarization proles in the high-resolution spectra of ε Eri, to increase the S/N ratio, the LSD me ...
Magnetic resonance imaging of laser polarized liquid xenon
... A second promising application of laser polarized xenon MRI is to investigate two-phase ~liquid-gas! phenomena. As a demonstration, we imaged xenon spins evaporating from the liquid into the vapor ~Fig. 2!, as well as condensing from the vapor into the liquid ~Fig. 3!. These images were acquired usi ...
... A second promising application of laser polarized xenon MRI is to investigate two-phase ~liquid-gas! phenomena. As a demonstration, we imaged xenon spins evaporating from the liquid into the vapor ~Fig. 2!, as well as condensing from the vapor into the liquid ~Fig. 3!. These images were acquired usi ...
Circular polarization
In electrodynamics, circular polarization of an electromagnetic wave is a polarization in which the electric field of the passing wave does not change strength but only changes direction in a rotary manner.In electrodynamics the strength and direction of an electric field is defined by what is called an electric field vector. In the case of a circularly polarized wave, as seen in the accompanying animation, the tip of the electric field vector, at a given point in space, describes a circle as time progresses. If the wave is frozen in time, the electric field vector of the wave describes a helix along the direction of propagation.Circular polarization is a limiting case of the more general condition of elliptical polarization. The other special case is the easier-to-understand linear polarization.The phenomenon of polarization arises as a consequence of the fact that light behaves as a two-dimensional transverse wave.