scholarly journals MAGNUM survey: compact jets causing large turmoil in galaxies. Enhanced line widths perpendicular to radio jets as tracers of jet-ISM interaction

2021 ◽  
Author(s):  
G. Venturi ◽  
G. Cresci ◽  
A. Marconi ◽  
M. Mingozzi ◽  
E. Nardini ◽  
...  
Keyword(s):  
Radio Jets ◽  
Line Widths

Line widths, sensitivity and artifacts in33S NMR Spectra: The case of aqueous sulphides

1986 ◽  
Vol 24 (11) ◽  
pp. 1004-1007 ◽  
Author(s):  
P. S. Belton ◽  
I. J. Cox ◽  
R. K. Harris
Keyword(s):  
Nmr Spectra ◽  
Line Widths

scholarly journals Large Bent Jets in the Inner Region of CSS

1996 ◽  
Vol 175 ◽  
pp. 71-72
Author(s):  
F. Mantovani ◽  
W. Junor ◽  
M. Bondi ◽  
L. Padrielli ◽  
W. Cotton ◽  
...  
Keyword(s):  
Velocity Structure ◽  
Radio Sources ◽  
Ambient Media ◽  
The Core ◽  
Gaseous Environment ◽  
Radio Jets ◽  
Large Size ◽  
Superluminal Motion ◽  
Inner Region ◽  
Quasars And Radio Galaxies

Recently we focussed our attention on a sample of Compact Steep-spectrum Sources (CSSs) selected because of the large bent radio jets seen in the inner region of emission. The largest distortions are often seen in sources dominated by jets, and there are suggestions that this might to some extent be due to projection effects. However, superluminal motion is rare in CSSs. The only case we know of so far is 3C147 (Alef at al. 1990) with a mildly superluminal speed of ≃ 1.3v/c. Moreover, the core fractional luminosity in CSSs is ≃ 3% and ≤ 0.4% for quasars and radio galaxies respectively. Similar values are found for large size radio sources i.e. both boosting and orientations in the sky are similar for the two classes of objects. An alternative possibility is that these bent-jet sources might also be brightened by interactions with the ambient media. There are clear indications that intrinsic distortions due to interactions with a dense inhomogeneous gaseous environment play an important role. Observational support comes from the large RMs found in CSSs (Taylor et al. 1992; Mantovani et al. 1994; Junor et al. these proc.) and often associated with strong depolarization (Garrington & Akujor, t.p.). The CSSs also have very luminous Narrow Line Regions emission, with exceptional velocity structure (Gelderman, t.p.).

scholarly journals Toward Engineering Intrinsic Line Widths and Line Broadening in Perovskite Nanoplatelets

ACS Nano ◽  
2021 ◽  
Vol 15 (4) ◽  
pp. 6499-6506
Author(s):  
Albert Liu ◽  
Gabriel Nagamine ◽  
Luiz G. Bonato ◽  
Diogo B. Almeida ◽  
Luiz F. Zagonel ◽  
...  
Keyword(s):  
Line Broadening ◽  
Line Widths

scholarly journals The Nature of the Chemical Anomalies of the Sirius A

1998 ◽  
Vol 11 (1) ◽  
pp. 391-391
Author(s):  
V. Leushin
Keyword(s):  
Magnetic Field ◽  
Oscillator Strengths ◽  
Helium Abundance ◽  
Surface Magnetic Field ◽  
Line Widths ◽  
Chemical Anomalies ◽  
Improved Accuracy

On the basis of the analysis of the observed equivalent line widths of FeI, FeII, and TiII in the spectra of Sirius A and Omicron Peg and calculation of abundances of these elements, the oscillator strengths of the lines used are refined. With the improved oscillator strengths, the iron and titanium abundances in the atmosphere of Sirius A are obtained with a higher accuracy than previously: lgN(FeI) = 7.899 ±0.011, lgN(FeII) = 7.908±0.010, lgN(TiII) =5.30±0.02. The improved accuracy allowed one to conclude that the surface magnetic field is absent in the atmosphere of Sirius A: H =3D 0±100 Gs. The equivalent widths of 7 helium lines of the red region of the spectrum are measured. The calculations of these lines (with allowance for their blending with lines of other elements) show normal helium abundance. Following a comparison of features of Sirius A and Omicron Peg, a suggestion is advanced on possible reasons for the existence of Am stars.

scholarly journals Gaseous Disks in the Nuclei of Elliptical Galaxies

1997 ◽  
Vol 163 ◽  
pp. 620-625 ◽  
Author(s):  
H. Ford ◽  
Z. Tsvetanov ◽  
L. Ferrarese ◽  
G. Kriss ◽  
W. Jaffe ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Accretion Disks ◽  
Large Scale ◽  
Elliptical Galaxies ◽  
Central Mass ◽  
Massive Black Holes ◽  
Radio Jets

AbstractHST images have led to the discovery that small (r ~ 1″ r ~ 100 – 200 pc), well-defined, gaseous disks are common in the nuclei of elliptical galaxies. Measurements of rotational velocities in the disks provide a means to measure the central mass and search for massive black holes in the parent galaxies. The minor axes of these disks are closely aligned with the directions of the large–scale radio jets, suggesting that it is angular momentum of the disk rather than that of the black hole that determines the direction of the radio jets. Because the disks are directly observable, we can study the disks themselves, and investigate important questions which cannot be directly addressed with observations of the smaller and unresolved central accretion disks. In this paper we summarize what has been learned to date in this rapidly unfolding new field.

scholarly journals Event Horizon Telescope observations of the jet launching and collimation in Centaurus A

2021 ◽  
Author(s):  
Michael Janssen ◽  
Heino Falcke ◽  
Matthias Kadler ◽  
Eduardo Ros ◽  
Maciek Wielgus ◽  
...  
Keyword(s):  
Black Holes ◽  
Event Horizon ◽  
Galactic Nuclei ◽  
Galactic Centre ◽  
Radio Jets ◽  
Long Baseline ◽  
Wide Range ◽  
Terahertz Frequencies ◽  
Source Structure ◽  
Centaurus A

AbstractVery-long-baseline interferometry (VLBI) observations of active galactic nuclei at millimetre wavelengths have the power to reveal the launching and initial collimation region of extragalactic radio jets, down to 10–100 gravitational radii (rg ≡ GM/c2) scales in nearby sources1. Centaurus A is the closest radio-loud source to Earth2. It bridges the gap in mass and accretion rate between the supermassive black holes (SMBHs) in Messier 87 and our Galactic Centre. A large southern declination of −43° has, however, prevented VLBI imaging of Centaurus A below a wavelength of 1 cm thus far. Here we show the millimetre VLBI image of the source, which we obtained with the Event Horizon Telescope at 228 GHz. Compared with previous observations3, we image the jet of Centaurus A at a tenfold higher frequency and sixteen times sharper resolution and thereby probe sub-lightday structures. We reveal a highly collimated, asymmetrically edge-brightened jet as well as the fainter counterjet. We find that the source structure of Centaurus A resembles the jet in Messier 87 on ~500 rg scales remarkably well. Furthermore, we identify the location of Centaurus A’s SMBH with respect to its resolved jet core at a wavelength of 1.3 mm and conclude that the source’s event horizon shadow4 should be visible at terahertz frequencies. This location further supports the universal scale invariance of black holes over a wide range of masses5,6.

scholarly journals Reacceleration of Relativistic Electrons by Turbulent Alfvén Waves in Radio Jets

2000 ◽  
Vol 195 ◽  
pp. 439-441
Author(s):  
D.-Y. Wang ◽  
Y. Ma
Keyword(s):  
Electron Energy ◽  
Power Law ◽  
Diffusion Approximation ◽  
Alfven Waves ◽  
Alfvén Waves ◽  
Relativistic Electrons ◽  
Radio Jets

Relativistic electrons may be effectively accelerated by turbulent Alfvén waves in radio jets. The acceleration spectrum is a power law with the electron energy as high as γ ~ 106, but the spectrum index is ~ 1.2 in the condition of diffusion approximation, which is less than the observation value.

OPTICAL ABSORPTION SPECTRA OF ARSENIC AND PHOSPHORUS IN SILICON

1962 ◽  
Vol 40 (10) ◽  
pp. 1480-1489 ◽  
Author(s):  
J. W. Bichard ◽  
J. C. Giles
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Excited States ◽  
Ground State ◽  
Absorption Lines ◽  
Full Width ◽  
Optical Absorption Spectra ◽  
Phosphorus Impurity ◽  
Line Widths ◽  
Phosphorus In Silicon

The optical absorption spectra of arsenic and phosphorus donor impurities in silicon have been studied under conditions of improved resolution. Absorption lines due to transitions from the impurity ground state to the excited states 2p0, 2p±, 3p0, 3p±, 4p0, 4 p±, and 5p0, and 5p± have been observed at 4.2° K. The relative intensities of some of these absorption lines are compared with existing experimental and theoretical estimates. The contribution of instrumental broadening to the observed line widths is assessed and natural line widths are estimated. The estimates indicate values for the natural line widths which are much less than those previously reported. For phosphorus impurity, the natural line widths are estimated to be less than 0.08 × 10−3 electron volts full width at half-maximum. The possibility of concentration broadening is discussed in connection with the arsenic data.

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