X‐Ray, Optical, and Radio Observations of the Type II Supernovae 1999em and 1998S

2002 ◽  
Vol 572 (2) ◽  
pp. 932-943 ◽  
Author(s):  
David Pooley ◽  
Walter H. G. Lewin ◽  
Derek W. Fox ◽  
Jon M. Miller ◽  
Christina K. Lacey ◽  
...  
Keyword(s):  
Type Ii ◽  
Radio Observations ◽  
X Ray

Developing structure-based models to predict substrate specificity of D-group (Type II) molybdenum enzymes: application to a molybdo-enzyme of unknown function from Archaeoglobus fulgidus

2006 ◽  
Vol 34 (1) ◽  
pp. 118-121 ◽  
Author(s):  
E.J. Dridge ◽  
D.J. Richardson ◽  
R.J. Lewis ◽  
C.S. Butler
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Sequence Analysis ◽  
Archaeoglobus Fulgidus ◽  
Substrate Selectivity ◽  
Type Ii ◽  
Amino Acid Residues ◽  
Sequence Alignments ◽  
X Ray ◽  
Group Type

The AF0174–AF0176 gene cluster in Archaeoglobus fulgidus encodes a putative oxyanion reductase of the D-type (Type II) family of molybdo-enzymes. Sequence analysis reveals that the catalytic subunit AF0176 shares low identity (31–32%) and similarity (41–42%) to both NarG and SerA, the catalytic components of the respiratory nitrate and selenate reductases respectively. Consequently, predicting the oxyanion substrate selectivity of AF0176 has proved difficult based solely on sequence alignments. In the present study, we have modelled both AF0176 and SerA on the recently determined X-ray structure of the NAR (nitrate reductase) from Escherichia coli and have identified a number of key amino acid residues, conserved in all known NAR sequences, including AF0176, that we speculate may enhance selectivity towards trigonal planar (NO3−) rather than tetrahedral (SeO42− and ClO4−) substrates.

Correlations of solar-flare electron events with radio and X-ray emission from the sun

1968 ◽  
Vol 46 (10) ◽  
pp. S757-S760 ◽  
Author(s):  
R. P. Lin
Keyword(s):  
Solar Flare ◽  
Solar Radio ◽  
Interplanetary Space ◽  
The Sun ◽  
Radio Bursts ◽  
Radio Observations ◽  
X Ray ◽  
Type Iii ◽  
Electron Event ◽  
Burst Emission

The > 40-keV solar-flare electrons observed by the IMP III and Mariner IV satellites are shown to be closely correlated with solar radio and X-ray burst emission. In particular, intense type III radio bursts are observed to accompany solar electron-event flares. The energies of the electrons, the total number of electrons, and the size of the electron source at the sun can be inferred from radio observations. The characteristics of the electrons observed in interplanetary space are consistent with these radio observations. Therefore these electrons are identified as the exciting agents of the type III emission. It has been noted that the radio and X-ray bursts are part of the flash phase of flares. The observations indicate that a striking feature of the flash phase is the production of electrons of 10–100 keV energies.

Detailed X-ray diffraction studies on optically pumped mid-infrared InAs/Ga(In)Sb/AlSb type-II lasers

2003 ◽  
Vol 257 (1-2) ◽  
pp. 42-50 ◽  
Author(s):  
G. Hoffmann ◽  
H.J. Schimper ◽  
C. Schwender ◽  
N. Herhammer ◽  
G.F. West ◽  
...  
Keyword(s):  
Type Ii ◽  
X Ray Diffraction ◽  
Optically Pumped ◽  
Mid Infrared ◽  
X Ray

Conditions needed for generation of type II radio emission in the interplanetary space

2021 ◽  
Author(s):  
Immanuel Christopher Jebaraj ◽  
Athanasios Kouloumvakos ◽  
Jasmina Magdalenic ◽  
Alexis Rouillard ◽  
Vratislav Krupar ◽  
...  
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Radio Emission ◽  
Interplanetary Space ◽  
Region Of Interest ◽  
Type Ii ◽  
Radio Observations ◽  
Wave Parameters ◽  
First Results ◽  
Radio Signature

<p>Eruptive events such as Coronal mass ejections (CMEs) and flares cangenerate shock waves. Tracking shock waves and predicting their arrival at Earth is a subject of numerous space weather studies. Ground-based radio observations allow us to locate shock waves in the low corona while space-based radio observations provide us opportunity to track shock waves in the inner heliosphere. We present a case study of CME/flare event, associated shock wave and its radio signature, i.e. type II radio burst.</p><p>In order to analyze the shock wave parameters, we employed a robust paradigm. We reconstructed the shock wave in 3D using multi-viewpoint observations and modelled the evolution of its parameters using a 3D MHD background coronal model produced by the MAS (Magnetohydrodynamics Around a Sphere).</p><p>To map regions on the shock wave surface, possibly associated with the electron acceleration, we combined 3D shock modelling results with the 3D source positions of the type II burst obtained using the radio triangulation technique. We localize the region of interest on the shock surface and examine the shock wave parameters to understand the relationship between the shock wave and the radio event. We analyzed the evolution of the upstream plasma characteristics and shock wave parameters during the full duration of the type II radio emission. First results indicate that shock wave geometry and its relationship with shock strength play an important role in the acceleration of electrons responsible for the generation of type II radio bursts.</p>

scholarly journals Warped disks during type II outbursts in Be/X-ray binaries: evidence from optical polarimetry

2018 ◽  
Vol 619 ◽  
pp. A19 ◽  
Author(s):  
P. Reig ◽  
D. Blinov
Keyword(s):  
Neutron Star ◽  
Structural Changes ◽  
Degree Of Polarization ◽  
Polarization Degree ◽  
Polarization Angle ◽  
Similar Amount ◽  
Type Ii ◽  
Line Profiles ◽  
X Ray ◽  
X Ray Binaries

Context. Current models that explain giant (type II) X-ray outbursts in Be/X-ray binaries (BeXB), are based on the idea of highly distorted disks. They are believed to occur when a misaligned and warped disk becomes eccentric, allowing the neutron star to capture a large amount of material. The BeXB 4U 0115+63 underwent two major outbursts in 2015 and 2017. Aims. Our aim is to investigate whether the structural changes in the disk expected during type II outbursts can be detected through optical polarimetry. Methods. We present the first optical polarimetric observations and new optical spectra of the BeXB 4U 0115+63 covering the period 2013–2017. We study in detail the shape of the Hα line profile and the polarization parameters before, during, and after the occurrence of a type II X-ray outburst. Results. We find significant changes in polarization degree and polarization angle and highly distorted line profiles during the 2017 X-ray outburst. The degree of polarization decreased by ∼1%, while the polarization angle, which is supposed to be related with the disk orientation, first increased by ∼10° in about two months and then decreased by a similar amount and on a similar timescale once the X-ray activity ceased. Conclusions. We interpret the polarimetric and spectroscopic variability as evidence for the presence of a warped disk.

Supernova Remnant Searches at Molonglo

1984 ◽  
Vol 5 (4) ◽  
pp. 537-540 ◽  
Author(s):  
A. J. Turtle ◽  
B. Y. Mills
Keyword(s):  
Supernova Remnants ◽  
Supernova Remnant ◽  
Magellanic Clouds ◽  
Radio Observations ◽  
X Ray

A catalogue of 38 supernova remnants (SNRs) identified in the Large and Small Magellanic Clouds from X-ray, optical and radio observations has recently been presented by Mills et al. (1984). One important consideration is the completeness of this catalogue and of the Galactic catalogues with which it is compared. These are currently being investigated.

scholarly journals Further joint X-ray, infrared, and radio observations of Cygnus X-3

1976 ◽  
Vol 207 ◽  
pp. 78 ◽  
Author(s):  
K. O. Mason ◽  
P. W. Sanford ◽  
E. E. Becklin ◽  
J. Elias ◽  
G. Neugebauer ◽  
...  
Keyword(s):  
Radio Observations ◽  
X Ray

scholarly journals Study of variability of 2MASSJ10183905+0014078 stellar objects

2019 ◽  
pp. 60-65
Author(s):  
E. C. Romas
Keyword(s):  
Spectral Characteristics ◽  
Type Ii ◽  
Slow Increase ◽  
Stellar Objects ◽  
X Ray ◽  
Spectral Class ◽  
Photometric Observations ◽  
Type Object ◽  
Brightness Variability ◽  
Made In

This paper presents observational data for the star 2MASSJ10183905+0014078 (UCAC4 452-048383), in which so far no brightness variability has been detected. However, photometric observations made in 2015 allowed recording are activity with an amplitude of 0.8 m for this star. The star parameters, namely magnitude and color index (V0 = 7.59, (B - V)0 = 1.19) and, therefore, the position on the Hertzsprung-Russell diagram, luminosity (L☉ = 0.1), spectral class (K7), mass (M☉ = 0.6), the spectral characteristics in the optical (Ca, Fe, Na D, H_ lines, Mg H, and TiO bands) and X-ray ranges allow us to classify the star as UVCet type object. The ash profile can be attributed to type II, with a relatively slow increase and decrease in brightness.

scholarly journals Detecting shocked intergalactic gas with X-ray and radio observations

2019 ◽  
Vol 627 ◽  
pp. A5 ◽  
Author(s):  
F. Vazza ◽  
S. Ettori ◽  
M. Roncarelli ◽  
M. Angelinelli ◽  
M. Brüggen ◽  
...  
Keyword(s):  
Large Scale ◽  
Intergalactic Medium ◽  
Thermal Emission ◽  
Intergalactic Gas ◽  
Radio Observations ◽  
X Ray ◽  
Large Scale Structures ◽  
Hot Gas ◽  
Scale Structures ◽  
Radio Band

Detecting the thermal and non-thermal emission from the shocked cosmic gas surrounding large-scale structures represents a challenge for observations, as well as a unique window into the physics of the warm-hot intergalactic medium. In this work, we present synthetic radio and X-ray surveys of large cosmological simulations in order to assess the chances of jointly detecting the cosmic web in both frequency ranges. We then propose best observing strategies tailored for existing (LOFAR, MWA, and XMM) or future instruments (SKA-LOW and SKA-MID, Athena, and eROSITA). We find that the most promising targets are the extreme peripheries of galaxy clusters in an early merging stage, where the merger causes the fast compression of warm-hot gas onto the virial region. By taking advantage of a detection in the radio band, future deep X-ray observations will probe this gas in emission, and help us to study plasma conditions in the dynamic warm-hot intergalactic medium with unprecedented detail.

scholarly journals Multifrequency VLA radio observations of the X-ray cavity cluster of galaxies RBS797: evidence of differently oriented jets

2006 ◽  
Vol 448 (3) ◽  
pp. 853-860 ◽  
Author(s):  
M. Gitti ◽  
L. Feretti ◽  
S. Schindler
Keyword(s):  
Radio Observations ◽  
X Ray ◽  
Cluster Of Galaxies
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