scholarly journals Long Slit Echelle Spectroscopy of Supernova Remnants in M33

1988 ◽  
Vol 101 ◽  
pp. 193-196
Author(s):  
William P. Blair ◽  
You-Hua Chu ◽  
Robert C. Kennicutt
Keyword(s):  
Supernova Remnants ◽  
Low Resolution ◽  
Low Velocity ◽  
Line Intensities ◽  
Echelle Spectroscopy ◽  
Resolution Data

AbstractWe have obtained long slit echelle spectroscopy for 10 of the brightest supernova remnants in M33 using the KPNO 4 m telescope. The profiles at Hα indicate bulk motions in the range 100–350 km s−1 in these remnants. Nearly all of the objects show signs of contamination by low velocity H II emission at some level. This affects the line intensities measured from low resolution data and may affect diameter measurements of these remnants.

Proteins and direct methods

1991 ◽  
Vol 197 (3-4) ◽  
Author(s):  
Fan Hai-fu ◽  
Hao Quan ◽  
M. M. Woolfson
Keyword(s):  
First Principles ◽  
Figure Of Merit ◽  
Direct Methods ◽  
Large Structure ◽  
Low Resolution ◽  
Figures Of Merit ◽  
Large Structures ◽  
Resolution Data

AbstractConventional direct methods, which work so well for small structures, are less successful for macromolecules. Where it has been demonstrated that a solution might be found using direct methods it is then found that the usual figures of merit are unable to distinguish the few good sets of phases from the large number of sets generated. The reasons for the difficulties with very large structures are considered from a first-principles approach taking into account both the factors of having a large number of atoms and low resolution data. A proposal is made for trying to recognize good phase sets by taking a large structure as a sum of a number of smaller structures for each of which a conventional figure of merit can be applied.

scholarly journals Interaction between molecular clouds and MeV–TeV cosmic-ray protons escaped from supernova remnants

2019 ◽  
Vol 71 (4) ◽  
Author(s):  
Ken Makino ◽  
Yutaka Fujita ◽  
Kumiko K Nobukawa ◽  
Hironori Matsumoto ◽  
Yutaka Ohira
Keyword(s):  
Gamma Rays ◽  
Molecular Clouds ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Iron Line ◽  
X Ray ◽  
Line Intensities ◽  
Neutral Gas ◽  
Additional Support

Abstract Recent discovery of the X-ray neutral iron line (Fe  i Kα at 6.40 keV) around several supernova remnants (SNRs) show that MeV cosmic-ray (CR) protons are distributed around the SNRs and are interacting with neutral gas there. We propose that these MeV CRs are the ones that have been accelerated at the SNRs together with GeV–TeV CRs. In our analytical model, the MeV CRs are still confined in the SNR when the SNR collides with molecular clouds. After the collision, the MeV CRs leak into the clouds and produce the neutral iron line emissions. On the other hand, GeV–TeV CRs had already escaped from the SNRs and emitted gamma-rays through interaction with molecular clouds surrounding the SNRs. We apply this model to the SNRs W 28 and W 44 and show that it can reproduce the observations of the iron line intensities and the gamma-ray spectra. This could be additional support of the hadronic scenario for the gamma-ray emissions from these SNRs.

scholarly journals An overview of heavy-atom derivatization of protein crystals

2016 ◽  
Vol 72 (3) ◽  
pp. 303-318 ◽  
Author(s):  
Ashley C. W. Pike ◽  
Elspeth F. Garman ◽  
Tobias Krojer ◽  
Frank von Delft ◽  
Elisabeth P. Carpenter
Keyword(s):  
Heavy Atom ◽  
Protein Crystals ◽  
Data Sets ◽  
Low Resolution ◽  
Heavy Atoms ◽  
Density Maps ◽  
Resolution Electron ◽  
First Choice ◽  
First Time ◽  
Resolution Data

Heavy-atom derivatization is one of the oldest techniques for obtaining phase information for protein crystals and, although it is no longer the first choice, it remains a useful technique for obtaining phases for unknown structures and for low-resolution data sets. It is also valuable for confirming the chain trace in low-resolution electron-density maps. This overview provides a summary of the technique and is aimed at first-time users of the method. It includes guidelines on when to use it, which heavy atoms are most likely to work, how to prepare heavy-atom solutions, how to derivatize crystals and how to determine whether a crystal is in fact a derivative.

On the Use of low-resolution Data to Improve Structure Prediction of Proteins and Protein Complexes

2009 ◽  
Vol 5 (11) ◽  
pp. 3129-3137 ◽  
Author(s):  
Marco D’Abramo ◽  
Tim Meyer ◽  
Pau Bernadó ◽  
Carles Pons ◽  
Juan Fernández Recio ◽  
...  
Keyword(s):  
Structure Prediction ◽  
Protein Complexes ◽  
Low Resolution ◽  
Resolution Data

scholarly journals Fast-Expanding Hi Shells Associated with Supernova Remnants in the I-GALFA Survey

2013 ◽  
Vol 9 (S296) ◽  
pp. 386-387
Author(s):  
Geumsook Park ◽  
Bon-Chul Koo ◽  
Steven J. Gibson ◽  
Ji-hyun Kang
Keyword(s):  
Physical Properties ◽  
Survey Data ◽  
Supernova Remnants ◽  
Good Sensitivity ◽  
Velocity Range ◽  
Statistical Nature ◽  
Low Resolution ◽  
Excess Emission ◽  
L Band ◽  
Hi Shells

AbstractWe examine excess emission at high positive and negative velocities toward known Galactic supernova remnants (SNRs) in the “Inner-Galaxy Arecibo L-band Feed Array (I-GALFA)” Hi 21-cm survey data. The I-GALFA survey covers ℓ = 32° to 77°, and has a velocity range of ±700 km s−1 with high angular and velocity resolutions (4′ and 0.18 km s−1, respectively) and good sensitivity (0.2 K). The excess emission which is thought to be part of a fast-expanding Hi shell of a SNR is detected from four among 39 SNRs in the I-GALFA area: W44, G54.4–0.3, W51C, and CTB 80. Although the Hi shells of the four SNRs were already reported in low-resolution studies, the first detection of both sides of an expanding Hi shell associated with W44 is very inspiring. We discuss physical properties of these four SNRs and their statistical nature.

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