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.

scholarly journals Multi-Sensor InSAR Analysis of Progressive Land Subsidence over the Coastal City of Urayasu, Japan

2018 ◽  
Vol 10 (8) ◽  
pp. 1304 ◽  
Author(s):  
Yusupujiang Aimaiti ◽  
Fumio Yamazaki ◽  
Wen Liu
Keyword(s):  
Synthetic Aperture Radar ◽  
Survey Data ◽  
Land Subsidence ◽  
Ground Deformation ◽  
Tohoku Earthquake ◽  
Synthetic Aperture ◽  
Alos Palsar ◽  
The 2011 Tohoku Earthquake ◽  
L Band ◽  
Aperture Radar

In earthquake-prone areas, identifying patterns of ground deformation is important before they become latent risk factors. As one of the severely damaged areas due to the 2011 Tohoku earthquake in Japan, Urayasu City in Chiba Prefecture has been suffering from land subsidence as a part of its land was built by a massive land-fill project. To investigate the long-term land deformation patterns in Urayasu City, three sets of synthetic aperture radar (SAR) data acquired during 1993–2006 from European Remote Sensing satellites (ERS-1/-2 (C-band)), during 2006–2010 from the Phased Array L-band Synthetic Aperture Radar onboard the Advanced Land Observation Satellite (ALOS PALSAR (L-band)) and from 2014–2017 from the ALOS-2 PALSAR-2 (L-band) were processed by using multitemporal interferometric SAR (InSAR) techniques. Leveling survey data were also used to verify the accuracy of the InSAR-derived results. The results from the ERS-1/-2, ALOS PALSAR and ALOS-2 PALSAR-2 data processing showed continuing subsidence in several reclaimed areas of Urayasu City due to the integrated effects of numerous natural and anthropogenic processes. The maximum subsidence rate of the period from 1993 to 2006 was approximately 27 mm/year, while the periods from 2006 to 2010 and from 2014 to 2017 were approximately 30 and 18 mm/year, respectively. The quantitative validation results of the InSAR-derived deformation trend during the three observation periods are consistent with the leveling survey data measured from 1993 to 2017. Our results further demonstrate the advantages of InSAR measurements as an alternative to ground-based measurements for land subsidence monitoring in coastal reclaimed areas.

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.

scholarly journals Disaggregation of Low-Resolution L-Band Radiometry Using C-Band Radar Data

2016 ◽  
Vol 13 (10) ◽  
pp. 1425-1429 ◽  
Author(s):  
C. Rudiger ◽  
C.-H. Su ◽  
D. Ryu ◽  
W. Wagner
Keyword(s):  
Radar Data ◽  
Low Resolution ◽  
L Band

scholarly journals K- and L-band spectroscopy of Be stars

2010 ◽  
Vol 6 (S272) ◽  
pp. 392-393
Author(s):  
Anahí Granada ◽  
María L. Arias ◽  
Lydia S. Cidale ◽  
Ronald E. Mennickent
Keyword(s):  
Physical Properties ◽  
Emission Lines ◽  
Circumstellar Disk ◽  
Be Stars ◽  
Circumstellar Envelopes ◽  
Hydrogen Emission ◽  
Group I ◽  
Hydrogen Emission Lines ◽  
L Band ◽  
Thick Medium

AbstractWe describe the behaviour of IR hydrogen emission lines of a sample of Be stars and discuss the physical properties of the circumstellar envelopes of Be stars classified in Groups I and II (Mennickent et al. 2009). We find that while Humphreys and Pfund lines of Group I stars form in an optically thick envelope/disk, Group II stars show Pfund lines that form in an optically thick medium and Humphreys lines originating in optically thinner regions. The transition between Groups I and II could be understood in terms of the evolution of the circumstellar disk of the star and might bring clues on the mechanism originating the Be phenomenon.

scholarly journals A study of Kepler supernova remnant: angular power spectrum estimation from radio frequency data

2019 ◽  
Vol 489 (4) ◽  
pp. 5866-5875
Author(s):  
Preetha Saha ◽  
Somnath Bharadwaj ◽  
Nirupam Roy ◽  
Samir Choudhuri ◽  
Debatri Chattopadhyay
Keyword(s):  
Power Spectrum ◽  
Power Law ◽  
Supernova Remnants ◽  
Ambient Medium ◽  
Spectrum Estimation ◽  
Angular Power Spectrum ◽  
Kolmogorov Turbulence ◽  
Wide Range ◽  
L Band ◽  
5 Ghz

ABSTRACT Supernova remnants (SNRs) have a variety of overall morphology as well as rich structures over a wide range of scales. Quantitative study of these structures can potentially reveal fluctuations of density and magnetic field originating from the interaction with ambient medium and turbulence in the expanding ejecta. We have used 1.5 GHz (L band) and 5 GHz (C band) VLA data to estimate the angular power spectrum Cℓ of the synchrotron emission fluctuations of the Kepler SNR. This is done using the novel, visibility-based, Tapered Gridded Estimator of Cℓ. We have found that, for ℓ = (1.9–6.9) × 104, the power spectrum is a broken power law with a break at ℓ = 3.3 × 104, and power-law index of −2.84 ± 0.07 and −4.39 ± 0.04 before and after the break, respectively. The slope −2.84 is consistent with 2D Kolmogorov turbulence and earlier measurements for the Tycho SNR. We interpret the break to be related to the shell thickness of the SNR (0.35 pc) which approximately matches ℓ = 3.3 × 104 (i.e. 0.48 pc). However, for ℓ > 6.9 × 104, the estimated Cℓ of L band is likely to have dominant contribution from the foregrounds while for C band the power-law slope −3.07 ± 0.02 is roughly consistent with 3D Kolmogorov turbulence like that observed at large ℓ for Cas A and Crab SNRs.

scholarly journals Further Discussion of Binary Star Radio Survey Data

1998 ◽  
Vol 15 (2) ◽  
pp. 183-188 ◽  
Author(s):  
E. Budding ◽  
O. B. Slee ◽  
K. Jones
Keyword(s):  
Physical Properties ◽  
Survey Data ◽  
Binary Stars ◽  
Binary Star ◽  
Special Property ◽  
Statistical Information ◽  
Early Type ◽  
Rs Cvn Stars ◽  
Dependent Behaviour ◽  
Heterogeneous Class

AbstractStatistical information on 8280 individual radio observations of binary stars, predominantly at 8·4 GHz using the Parkes 64 m antenna, is presented. Three main groups are distinguished: (i) RS CVn stars, (ii) classical Algol binaries (EA2s), and (iii) detached pairs of generally early type (ETBs).The RS CVn stars more frequently gave rise to detectable fluxes, while the ETBs, in these data, are a small and rather heterogeneous class. The Algols' emission appears to increase near conjunction phases, though we cannot clearly distinguish any special property of the Algols' phase-dependent behaviour that is not also shared by the RS CVn binaries. Both these categories' data show a bimodal, phase-dependent pattern to the distribution of detections, suggesting that these binary types share similar underlying physical properties, though there could also be other factors at play. The sample sizes of the Algols and particularly the ETB detections are too small for effective, discriminatory statistics, however.

scholarly journals Physical Properties of 299 NEOs Manually Recovered in Over Five Years of NEOWISE Survey Data

2020 ◽  
Vol 1 (1) ◽  
pp. 9
Author(s):  
Joseph R. Masiero ◽  
Patrice Smith ◽  
Lean D. Teodoro ◽  
A. K. Mainzer ◽  
R. M. Cutri ◽  
...  
Keyword(s):  
Physical Properties ◽  
Survey Data

scholarly journals Bridging the gap between supernovae and their remnants through multi-dimensional hydrodynamic modeling

2017 ◽  
Vol 12 (S331) ◽  
pp. 258-267
Author(s):  
S. Orlando ◽  
M. Miceli ◽  
O. Petruk
Keyword(s):  
Physical Properties ◽  
Uniform Distribution ◽  
Supernova Remnants ◽  
Numerical Models ◽  
Hydrodynamic Models ◽  
Cassiopeia A ◽  
Sn 1987A ◽  
Complex Morphology ◽  
Extended Sources ◽  
Early Interaction

AbstractSupernova remnants (SNRs) are diffuse extended sources characterized by a complex morphology and a non-uniform distribution of ejecta. Such a morphology reflects pristine structures and features of the progenitor supernova (SN) and the early interaction of the SN blast wave with the inhomogeneous circumstellar medium (CSM). Deciphering the observations of SNRs might open the possibility to investigate the physical properties of both the interacting ejecta and the shocked CSM. This requires accurate numerical models which describe the evolution from the SN explosion to the remnant development and which connect the emission properties of the remnants to the progenitor SNe. Here we show how multi-dimensional SN-SNR hydrodynamic models have been very effective in deciphering observations of SNR Cassiopeia A and SN 1987A, thus unveiling the structure of ejecta in the immediate aftermath of the SN explosion and constraining the 3D pre-supernova structure and geometry of the environment surrounding the progenitor SN.

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