scholarly journals High Velocity Outflows in IRAS 17423-1755

1993 ◽  
Vol 155 ◽  
pp. 348-348
Author(s):  
A. Riera ◽  
P. García-Lario ◽  
A. Manchado ◽  
S.R. Pottasch
Keyword(s):  
High Resolution ◽  
High Velocity ◽  
Planetary Nebula ◽  
Optical Spectra ◽  
Bipolar Structure ◽  
La Palma ◽  
Pn Stage ◽  
Observational Program

IRAS 17423-1755 is a new transition object between the post-AGB phase and the planetary nebula (PN) stage included in an observational program of IRAS sources with infrared colours similar to those of PNe. We have taken B, V, R, I, Z, Hα and [OIII] CCD images at the 1m JKT (Roque de los Muchachos, La Palma), where a clearly marked bipolar structure with a total extension of about 10″ can be seen, and long slit (low and high resolution) optical spectra at the 4.2m WHT, 2.5m INT (RM, La Palma) and ESO 1.5m (La Silla) telescopes.

scholarly journals Morphological and kinematical analysis of the planetary nebula Hu 1-2 and its irradiated bow-shocks

2011 ◽  
Vol 7 (S283) ◽  
pp. 440-441
Author(s):  
Luis F. Miranda ◽  
Mónica Blanco ◽  
Martín A. Guerrero ◽  
Angels Riera
Keyword(s):  
High Resolution ◽  
High Velocity ◽  
Planetary Nebula ◽  
Narrow Band ◽  
Central Star ◽  
Kinematical Analysis ◽  
Near Ir ◽  
Bow Shocks

AbstractWe present narrow-band optical and near-IR images, and high-resolution long-slit spectra of the planetary nebula Hu 1-2 that allow us to make a detailed description of its unusual morphology and internal kinematics. The data also reveal that the ansae of Hu 1-2 probably represent bow-shocks associated to high velocity outflows that are irradiated from the central star.

High‐Resolution X‐Ray Image of the Hydrogen‐deficient Planetary Nebula Abell 30

1997 ◽  
Vol 482 (2) ◽  
pp. 891-896 ◽  
Author(s):  
You‐Hua Chu ◽  
Thomas H. Chang ◽  
Gail M. Conway
Keyword(s):  
High Resolution ◽  
Planetary Nebula ◽  
X Ray

scholarly journals The high-velocity outflow in the proto-planetary nebula Hen 3–1475

2003 ◽  
Vol 401 (3) ◽  
pp. 1039-1056 ◽  
Author(s):  
A. Riera ◽  
P. García-Lario ◽  
A. Manchado ◽  
M. Bobrowsky ◽  
R. Estalella
Keyword(s):  
High Velocity ◽  
Planetary Nebula

scholarly journals Structure-controlled asperities of the 1920 Haiyuan M8.5 and 1927 Gulang M8 earthquakes, NE Tibet, China, revealed by high-resolution seismic tomography

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Quan Sun ◽  
Shunping Pei ◽  
Zhongxiong Cui ◽  
Yongshun John Chen ◽  
Yanbing Liu ◽  
...  
Keyword(s):  
High Resolution ◽  
Seismic Tomography ◽  
High Velocity ◽  
Three Dimensional ◽  
Large Earthquake ◽  
Velocity Model ◽  
Tectonic Stress ◽  
Double Difference ◽  
Source Regions ◽  
Large Earthquakes

AbstractDetailed crustal structure of large earthquake source regions is of great significance for understanding the earthquake generation mechanism. Numerous large earthquakes have occurred in the NE Tibetan Plateau, including the 1920 Haiyuan M8.5 and 1927 Gulang M8 earthquakes. In this paper, we obtained a high-resolution three-dimensional crustal velocity model around the source regions of these two large earthquakes using an improved double-difference seismic tomography method. High-velocity anomalies encompassing the seismogenic faults are observed to extend to depths of 15 km, suggesting the asperity (high-velocity area) plays an important role in the preparation process of large earthquakes. Asperities are strong in mechanical strength and could accumulate tectonic stress more easily in long frictional locking periods, large earthquakes are therefore prone to generate in these areas. If the close relationship between the aperity and high-velocity bodies is valid for most of the large earthquakes, it can be used to predict potential large earthquakes and estimate the seismogenic capability of faults in light of structure studies.

scholarly journals 5.18. Molecular gas in the poststarburst galaxy NGC7331

1998 ◽  
Vol 184 ◽  
pp. 247-248
Author(s):  
T. Tosaki ◽  
Y. Shioya
Keyword(s):  
High Resolution ◽  
Spiral Galaxy ◽  
Stellar Populations ◽  
Optical Spectra ◽  
Molecular Gas ◽  
Early Type ◽  
Origin And Evolution ◽  
Co Observations

To understand the origin and evolution of starburst activity, we must study the full evolution of starburst; i.e., pre-, on-going, and post-starburst phases. It seems reasonable to suppose the numerous A-type stars indicate past starburst and they show strong Balmer absorption. NGC7331, nearby early-type spiral galaxy, is one of the poststarburst galaxies which show strong Balmer absorption. The optical spectra of NGC7331 were dominated by component of intermediate-age (5 × 109 years) stellar populations (Ohyama & Taniguchi 1996). We present the result of the high resolution CO observations of NGC7331 using Nobeyama Milimeter Array.

The magnetic structure and dynamics of a decaying active region

2019 ◽  
Vol 15 (S354) ◽  
pp. 53-57
Author(s):  
Ioannis Kontogiannis ◽  
Christoph Kuckein ◽  
Sergio Javier González Manrique ◽  
Tobias Felipe ◽  
Meetu Verma ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Time Series ◽  
High Resolution ◽  
Active Region ◽  
Magnetic Structure ◽  
High Velocity ◽  
Solar Dynamics Observatory ◽  
Multi Wavelength ◽  
Convective Motions ◽  
Field Lines

AbstractWe study the evolution of the decaying active region NOAA 12708, from the photosphere up to the corona using high resolution, multi-wavelength GREGOR observations taken on May 9, 2018. We utilize spectropolarimetric scans of the 10830 Å spectral range by the GREGOR Infrared Spectrograph (GRIS), spectral imaging time-series in the Na ID2 spectral line by the GREGOR Fabry-Pérot Interferometer (GFPI) and context imaging in the Ca IIH and blue continuum by the High-resolution Fast Imager (HiFI). Context imaging in the UV/EUV from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) complements our dataset. The region under study contains one pore with a light-bridge, a few micro-pores and extended clusters of magnetic bright points. We study the magnetic structure from the photosphere up to the upper chromosphere through the spectropolarimetric observations in He II and Si I and through the magnetograms provided by the Helioseismic and Magnetic Imager (HMI). The high-resolution photospheric images reveal the complex interaction between granular-scale convective motions and a range of scales of magnetic field concentrations in unprecedented detail. The pore itself shows a strong interaction with the convective motions, which eventually leads to its decay, while, under the influence of the photospheric flow field, micro-pores appear and disappear. Compressible waves are generated, which are guided towards the upper atmosphere along the magnetic field lines of the various magnetic structures within the field-of-view. Modelling of the He i absorption profiles reveals high velocity components, mostly associated with magnetic bright points at the periphery of the active region, many of which correspond to asymmetric Si I Stokes-V profiles revealing a coupling between upper photospheric and upper chromospheric dynamics. Time-series of Na ID2 spectral images reveal episodic high velocity components at the same locations. State-of-the-art multi-wavelength GREGOR observations allow us to track and understand the mechanisms at work during the decay phase of the active region.

scholarly journals Precise Radial Velocity Measurements with a Cassegrain Spectrograph, I: Wavelength calibration

1999 ◽  
Vol 170 ◽  
pp. 63-67
Author(s):  
I. V. Ilyin ◽  
R. Duemmler
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Cross Correlation ◽  
Time Dependent ◽  
Instrumental Effects ◽  
Velocity Measurements ◽  
Echelle Spectrograph ◽  
Optical Telescope ◽  
La Palma ◽  
Observational Strategy

AbstractWe briefly describe the instrumental effects which affect the accuracy of the radial velocity measurements. We have implemented several methods to correct for the instability effects and improve the accuracy of the measurements. These include modifications of the observational strategy and a time-dependent wavelength solution as well as a discussion of the error of the offset from cross-correlation. These methods are applied to observations obtained with the high resolution échelle spectrograph SOFIN mounted at the Cassegrain focus of the alt-azimuth 2.56-m Nordic Optical Telescope, La Palma, Canary Islands.

scholarly journals Morphological Characteristics of Compact High-Velocity Clouds Revealed by High-Resolution WSRT Imaging

2000 ◽  
Vol 174 ◽  
pp. 136-147
Author(s):  
W. B. Burton ◽  
R. Braun
Keyword(s):  
Dark Matter ◽  
High Resolution ◽  
High Velocity ◽  
Physical State ◽  
Local Group ◽  
Morphological Characteristics ◽  
Kinetic Temperature ◽  
High Resolution Imaging ◽  
Resolution Imaging ◽  
High Velocity Clouds

AbstractA class of compact, isolated high–velocity clouds which plausibly represents a homogeneous subsample of the HVC phenomenon in a single physical state was objectively identified by Braun and Burton (1999). Six examples of the CHVCs, unresolved in single–dish data, have been imaged with the Westerbork Synthesis Radio Telescope. The high–resolution imaging reveals the morphology of these objects, including a core/halo distribution of fluxes, signatures of rotation indicating dark matter, and narrow linewidths constraining the kinetic temperature of several opaque cores. In these regards, as well as in their kinematic and spatial deployment on the sky, the CHVC objects are evidently a dynamically cold ensemble of dark–matter–dominated H ɪ clouds accreting onto the Local Group in a continuing process of galactic evolution.

scholarly journals The Structure of the HH39 Region

1987 ◽  
Vol 115 ◽  
pp. 340-341
Author(s):  
J. R. Walsh
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Proper Motion ◽  
High Velocity ◽  
Velocity Structure ◽  
The Other ◽  
Emission Lines ◽  
High Resolution Spectroscopy ◽  
Bow Shocks ◽  
Hh Objects

HH39 is the group of Herbig-Haro (HH) objects associated with the young semi-stellar object R Monocerotis (R Mon) and the variable reflection nebula NGC 2261. An R CCD frame and a B prime focus plate of the region show a filament connecting NGC 2261 with HH39, confirming the association between R Mon and the HH objects. This filament is probably composed of emission material. The southern knot in HH39 has brightened over the last 20 years; its proper motion has been determined and is similar to that of the other knots. A total of 8 knots can be distinguished in HH39 surrounded by diffuse nebulosity. High resolution spectroscopy of the Hα and [N II] emission lines shows the spatial variation of the radial velocity structure over the largest knots (HH39 A and C). Distinct differences in excitation and velocity structure between the knots are apparent. The observations are compatible with the knots being high velocity ejecta from R Mon, decelerated by interaction with ambient material and with bow shocks on their front surfaces.

scholarly journals Small Galactic Nebulae

1987 ◽  
Vol 115 ◽  
pp. 191-192
Author(s):  
Yervant Terzian ◽  
Kenneth C. Turner
Keyword(s):  
High Resolution ◽  
Planetary Nebula ◽  
Physical Parameters ◽  
H Ii Regions ◽  
Radio Observations ◽  
Cluster Emission ◽  
Active Star ◽  
Star Forming ◽  
Cometary Nebula ◽  
Significant Flux

We have performed high resolution VLA radio observations for several small H II regions, including the cluster emission nebulae S258, S255, S257, and S256. The region (PP56) between S255 and S257 at λ2 cm reveals significant flux structure close to OH, H2O and infrared emitting sources as shown in Figure 1. The flux densities and positions are indicated in Table 1. Observations of the cometary nebula PP59 (S269) also reveal similar characteristics as shown in Figure 2. These regions are considered to be active star-forming clouds. The cometary nebula PP40 was also observed and we note that its physical parameters are very similar to those of a typical planetary nebula.

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