Theory of Photons in a Fully Ionized Gas. I. Photon Momentum Distribution

1969 ◽  
Vol 177 (1) ◽  
pp. 359-370 ◽  
Author(s):  
In Kil Hwang ◽  
W. T. Grandy
Keyword(s):  
Momentum Distribution ◽  
Photon Momentum ◽  
Ionized Gas

Positron annihilation in alloys

1977 ◽  
Vol 55 (15) ◽  
pp. 1335-1341 ◽  
Author(s):  
K. M. Hong ◽  
J. P. Carbotte
Keyword(s):  
Positron Annihilation ◽  
Momentum Distribution ◽  
Coherent Potential Approximation ◽  
Fermi Momentum ◽  
Photon Momentum ◽  
Numerical Computations ◽  
Potential Approximation ◽  
Momentum Distributions ◽  
Annihilation Photon

A coherent potential approximation (CPA) treatment of positron annihilation in an alloy is presented. Simple formulae for the spatial and the momentum distributions of the positrons are derived. Numerical computations are performed to illustrate the effects of the smearing of the positron momentum distribution and of the electron Fermi momentum of the annihilation photon momentum distribution.

Prediction of momentum distribution of supercooled atoms in optical lattice using convolutional-recurrent network

2020 ◽  
Vol 28 (7) ◽  
pp. 1480-1484
Author(s):  
Yun-hong LI ◽  
◽  
Hong-hao LI ◽  
Da WEN ◽  
Fan-su WEI ◽  
...  
Keyword(s):  
Momentum Distribution ◽  
Optical Lattice ◽  
Recurrent Network

The Structure and Morphology of the Ionized Gas in Starburst Galaxies: NGC 5253/5236

1999 ◽  
Vol 118 (2) ◽  
pp. 797-816 ◽  
Author(s):  
Daniela Calzetti ◽  
Christopher J. Conselice ◽  
John S. Gallagher III ◽  
Anne L. Kinney
Keyword(s):  
Starburst Galaxies ◽  
Ionized Gas ◽  
Structure And Morphology

Stellar and Ionized‐Gas Kinematics of the Seyfert 1 Galaxy NGC 3516

1997 ◽  
Vol 490 (1) ◽  
pp. 227-237 ◽  
Author(s):  
S. Arribas ◽  
E. Mediavilla ◽  
B. Garcia‐Lorenzo ◽  
C. del Burgo
Keyword(s):  
Ionized Gas ◽  
Gas Kinematics

scholarly journals Ionized gas kinematics of massive elliptical galaxies in CALIFA and in cosmological zoom-in simulations

2020 ◽  
Vol 635 ◽  
pp. A41
Author(s):  
Jan Florian ◽  
Bodo Ziegler ◽  
Michaela Hirschmann ◽  
Polychronis Papaderos ◽  
Ena Choi ◽  
...  
Keyword(s):  
Radial Profile ◽  
Major Axis ◽  
Velocity Fields ◽  
Host Galaxies ◽  
Ionized Gas ◽  
Massive Galaxies ◽  
Gas Kinematics ◽  
Major Merger ◽  
Ordered Motion ◽  
Integral Field

Context. Powerful active galactic nuclei (AGN) are supposed to play a key regulatory role on the evolution of their host galaxies by shaping the thermodynamic properties of their gas component. However, little is known as to the nature and the visibility timescale of the kinematical imprints of AGN-driven feedback. Gaining theoretical and observational insights into this subject is indispensable for a thorough understanding of the AGN-galaxy coevolution and could yield empirical diagnostics for the identification of galaxies that have experienced a major AGN episode in the past. Aims. We present an investigation of kinematical imprints of AGN feedback on the warm ionized gas medium (WIM) of massive early-type galaxies (ETGs). To this end, we take a two-fold approach that involves a comparative analysis of Hα velocity fields in 123 local ETGs from the CALIFA (Calar Alto Legacy Integral Field Area Survey) integral field spectroscopy survey with 20 simulated galaxies from high-resolution hydrodynamic cosmological SPHgal simulations. The latter were resimulated for two modeling setups, one with and another without AGN feedback. Methods. In order to quantify the effects of AGN feedback on gas kinematics, we measured three parameters that probe deviations from simple regular rotation by using the kinemetry package. These indicators trace the possible presence of distinct kinematic components in Fourier space (k3, 5/k1), variations in the radial profile of the kinematic major axis (σPA), and offsets between the stellar and gas velocity fields (Δϕ). These quantities were monitored in the simulations from a redshift 3 to 0.2 to assess the connection between black hole accretion history, stellar mass growth, and the kinematical perturbation of the WIM. Results. Observed local massive galaxies show a broad range of irregularities, indicating disturbed warm gas motions, which is irrespective of being classified via diagnostic lines as AGN or not. Simulations of massive galaxies with AGN feedback generally exhibit higher irregularity parameters than without AGN feedback, which is more consistent with observations. Besides AGN feedback, other processes like major merger events or infalling gas clouds can lead to elevated irregularity parameters, but they are typically of shorter duration. More specifically, k3, 5/k1 is most sensitive to AGN feedback, whereas Δϕ is most strongly affected by gas infall. Conclusions. We conclude that even if the general disturbance of the WIM velocity is not a unique indicator for AGN feedback, irregularity parameters that are high enough to be consistent with observations can only be reproduced in simulations with AGN feedback. Specifically, an elevated value for the deviation from simple ordered motion is a strong sign for previous events of AGN activity and feedback.

Radio recombination line observations towards Spitzer infrared bubbles with the TianMa radio telescope

2019 ◽  
Vol 489 (4) ◽  
pp. 4862-4874
Author(s):  
L G Hou ◽  
X Y Gao
Keyword(s):  
Radio Telescope ◽  
Detection Rate ◽  
Milky Way ◽  
Absorption Method ◽  
Recombination Line ◽  
Ionized Gas ◽  
Radio Recombination Line ◽  
Warm Ionized Medium

ABSTRACT Many of the Spitzer infrared bubbles identified by the Milky Way Project (MWP) are suggested to be $\rm{H \small {II}} $ regions in nature. More than 70 per cent of the ∼5000 known bubbles do not have radio recombination line (RRL) observations, hence have not been confirmed as $\rm{H \small {II}} $ regions. A systematic RRL survey should be helpful to identify the nature of the bubbles. With the Shanghai TianMa 65-m radio telescope, we searched for RRLs towards 216 selected Spitzer bubbles by simultaneously observing 19 RRLs in the C band (4–8 GHz). RRLs are detected in the directions of 75 of the 216 targets. 31 of the 75 RRL sources are classified as new detections, which are possibly from new $\rm{H \small {II}} $ regions or diffuse warm ionized medium; 36 of them are probably from the outskirts of nearby bright $\rm{H \small {II}} $ regions, rather than bubble-encircled ionized gas; and the detected RRLs towards 8 bubbles are identified from known $\rm{H \small {II}} $ regions. For 58 of the 75 RRL sources, we obtained their distances after resolving the kinematic distance ambiguity by combining the results of the H2CO absorption method, the $\rm{H \small {I}} $ emission/absorption method, and the $\rm{H \small {I}} $ self-absorption method. The low detection rate of new $\rm{H \small {II}} $ regions implies that a number of MWP bubbles in the DR1 catalogue are too faint if they are $\rm{H \small {II}} $ regions.

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