scholarly journals Wave Structure within HI Filaments at High Galactic Latitude and the Nature of “Clouds” in Interstellar Space

1991 ◽  
Vol 144 ◽  
pp. 93-96
Author(s):  
Gerrit L. Verschuur
Keyword(s):  
High Resolution ◽  
High Latitude ◽  
High Velocity ◽  
Large Amplitude ◽  
Wave Structure ◽  
Interstellar Space ◽  
Galactic Latitude ◽  
High Galactic Latitude ◽  
Field Geometry ◽  
High Velocity Clouds

Large amplitude waves have been found in the morphology and velocity patterns of several long filaments of HI at high latitude. HI in the filaments is controlled by magnetic fields and the velocity patterns and morphology bear the hallmarks of Alfvén waves. Enhanced emission features (EEFs), traditionally referred to as “clouds,” are seen wherever a segment of flux tube is viewed end-on. This suggests that HI emission structure teaches us about field geometry and not about cloud physics. Similar effects have been recognized in other regions mapped with high-resolution as well as in completely mapped high-velocity “clouds.”

scholarly journals The Intermediate Velocity Cloud IVC86+38.5-45, Related to High Velocity Clouds?

1989 ◽  
Vol 120 ◽  
pp. 458-458
Author(s):  
U. Herbstmeier
Keyword(s):  
High Velocity ◽  
Galactic Disk ◽  
Dust Cloud ◽  
Galactic Latitude ◽  
High Galactic Latitude ◽  
High Velocity Clouds ◽  
Cloud Complex ◽  
Galactic Longitude ◽  
Velocity Cloud ◽  
High Velocity Cloud

Examining the high velocity cloud complex C and its possible interaction with gas of the galactic disk we became aware of a dust cloud located at galactic longitude l = 86° and latitude b = 38°.5 seen in the l00µm image of the IRAS. This cloud consists of a cucumber shaped core surounded by a horseshoe shaped halo opening towards larger galactic coordinates. At very low 100µm intensities dust lanes starting at the core or the ends of the horseshoe can be traced for about 5° towards high galactic latitude and longitude.

scholarly journals Detection of Hα Emission on High Velocity 21 cm Clouds

1990 ◽  
Vol 139 ◽  
pp. 193-198
Author(s):  
Guido Münch ◽  
Eckhart Pitz
Keyword(s):  
High Velocity ◽  
Galactic Latitude ◽  
Emission Rates ◽  
High Galactic Latitude ◽  
Continuum Intensity ◽  
Lyman Continuum ◽  
Local Standard ◽  
Direct Measurements ◽  
Hα Emission ◽  
Local Standard Of Rest

The measurement of Hα emission on two high galactic latitude clouds known to emit 21 cm lines with local standard of rest (LSR) velocities of −50 and −85 km s−1 is reported. The Hα lines have been found nearly at the velocities of the 21 CM features and have emission rates of 0.2 Rayleigh. The diffuse Lyman continuum intensity required to produce HI ionization at the measured rate is in agreement with the direct measurements made with the ultraviolet (UV) spectrometer of the Voyager 2 spacecraft.

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 mysterious high-latitude O-star HD 93521: new results from XMM-Newton observations

2010 ◽  
Vol 6 (S272) ◽  
pp. 612-613
Author(s):  
Gregor Rauw ◽  
Thierry Morel
Keyword(s):  
High Latitude ◽  
Galactic Latitude ◽  
High Galactic Latitude ◽  
The Subject

AbstractThe O9.5 Vp star HD 93521 is a well known non-radial pulsator located at a high Galactic latitude. The nature (Population I vs. II) of this star has been the subject of controversy for many years. We report on an XMM-Newton observation of the star that sheds new light on its nature.

scholarly journals Star Formation at High Galactic Latitude: A Case for Extensions to the Hα Survey

1998 ◽  
Vol 15 (1) ◽  
pp. 155-156 ◽  
Author(s):  
Kristen A. Larson
Keyword(s):  
Star Formation ◽  
High Latitude ◽  
T Tauri Stars ◽  
Young Stellar Objects ◽  
Galactic Latitude ◽  
Stellar Objects ◽  
High Galactic Latitude ◽  
T Tauri

AbstractThe AAO/UKST Hα Survey should be extended to high Galactic latitude (∣b∣ > 25°) to search for T Tauri stars. The Hα Survey can contribute to a complete inventory of young stellar objects in high-latitude clouds, which will help define the limits of conditions and processes that lead to star formation.

Ariel results on extragalactic X-ray sources

1976 ◽  
Vol 350 (1663) ◽  
pp. 491-503 ◽  
Keyword(s):  
High Latitude ◽  
Field Of View ◽  
Potential Contribution ◽  
Galactic Latitude ◽  
Survey Experiment ◽  
Spectral Measurements ◽  
High Galactic Latitude ◽  
X Ray ◽  
X Ray Background ◽  
The University

Two of the instruments on Ariel 5 are designed to study the weak high galactic latitude X-ray sources, a number of which have been identified with extragalactic objects. The survey experiment of the University of Leicester has detected sources with strengths down to 2-3 Uhuru counts. Several high latitude sources catalogued by Uhuru have apparently dropped in intensity below this level and improved positions have been obtained for other high latitude sources which support the tentative identification with optical counterparts. The pointed instrument from M. S. S. L. has a programme of spectral measurements of identified extragalactic and other weak sources at high galactic latitudes. The field of view of the M. S. S. L. experiment makes the instrument well suited to the study of the diffuse X-ray background. Results are presented from both experiments on a number of the extragalactic sources and, in particular, discussed in relation to their potential contribution to the diffuse X-ray background. Preliminary measurements of the diffuse X-ray background by the M. S. S. L. instruments are presented.

Sign in / Sign up

Export Citation Format

Share Document