scholarly journals 3 mm band line survey toward the high-velocity compact cloud CO−0.40−0.22

2013 ◽  
Vol 9 (S303) ◽  
pp. 202-204
Author(s):  
T. Oka ◽  
K. Tanaka ◽  
S. Matsumura ◽  
K. Miura ◽  
S. Takekawa ◽  
...  
Keyword(s):  
High Velocity ◽  
Velocity Structure ◽  
Frequency Resolution ◽  
Shock Acceleration ◽  
Line Profiles ◽  
Recent Past ◽  
Frequency Range ◽  
Large Velocity ◽  
Line Survey ◽  
Prominent Peak

AbstractHigh-velocity compact clouds (HVCCs) are a population of molecular clouds which have compact appearance (d < 10 pc) and large velocity width (Δ V > 50 km s−1), and are found in the central molecular zone of our Galaxy. We performed a 3 mm band line survey toward CO−0.40−0.22, a spatially unresolved HVCC with an extremely large velocity width (Δ V ≃ 90 km s−1), using the Mopra 22 m telescope. We surveyed the frequency range between 76 GHz and 116 GHz with a 0.27 MHz frequency resolution. We detect at least 54 lines from 32 molecules. Many line profiles show a prominent peak at vLSR ∼ 70 km s−1 with very large velocity width, indicating they are emitted by the HVCC. Detections of largish molecules are indicative of non-equilibrium chemistry. We extracted some prominent lines based on velocity structure, intensity ratios, and PCA analyses. Shock diagnostic lines (SiO, SO, CH3OH, HNCO) and dense gas probes (HCN, HCO+) appear to be prominent. Excitation analysis of CH3OH lines show an enhancement in Trot in the negative high-velocity end of the profile. These results suggest that CO−0.40−0.22 has experienced a shock, acceleration, compression, and heating in the recent past.

scholarly journals Discovery of large-scale masers in W3(OH)

2006 ◽  
Vol 2 (S237) ◽  
pp. 422-422
Author(s):  
L. Harvey-Smith ◽  
R. J. Cohen
Keyword(s):  
Velocity Gradient ◽  
Large Scale ◽  
Velocity Structure ◽  
Central Star ◽  
Line Profiles ◽  
Maser Emission ◽  
Methanol Maser ◽  
Large Velocity ◽  
Structure Line ◽  
Large Velocity Gradient

AbstractWe report a vast filament of hydroxyl and methanol maser emission surrounding the ultra-compact HII region W3(OH). The filament stretches 3100 AU and has a linear velocity gradient. By studying the velocity structure, line profiles and extended methanol maser structures we believe we have located the position of the central star and detected around it a circumstellar disc with a large velocity gradient of 47 km s−1 arcsec−1.

scholarly journals Structure of the crust and uppermost mantle beneath the Sicily channel from ambient noise and earthquake tomography

2020 ◽  
Vol 63 (Vol 63 (2020)) ◽  
Author(s):  
Radia Kherchouche ◽  
Merzouk Ouyed ◽  
Abdelkrim Aoudia ◽  
Billel Mellouk ◽  
Ahmed Saadi
Keyword(s):  
High Velocity ◽  
Ambient Noise ◽  
Velocity Structure ◽  
Dispersion Curves ◽  
Mount Etna ◽  
Uppermost Mantle ◽  
Velocity Models ◽  
Phase Velocity Dispersion ◽  
Sicily Channel ◽  
Tyrrhenian Basin

•  In this work, we study the crust and the uppermost mantle structure beneath the Sicily Channel, by applying the ambient noise and earthquake tomography method. After computing cross-correlation of the continuous ambient noise signals and processing the earthquake data, we extracted 104 group velocity and 68 phase velocity dispersion curves corresponding to the fundamental mode of the Rayleigh waves. We computed the average velocity of those dispersion curves to obtain tomographic maps at periods ranging from 5 s to 40 s for the group velocities and from 10 s to 70 for the phase velocities. We inverted group and phase speeds to get the shear-wave velocity structure from the surface down to 100 km depth with a lateral resolution of about 200 km. The resulted velocity models reveal a thin crust with thickness value of 15 km beneath the southern part of the Tyrrhenian basin and a thickness value of 20 km beneath Mount Etna. The obtained thickness values are well correlated with the reported extension of the Tyrrhenian lithosphere due to the past earthquake tomography subduction and rollback of the Ionian slab beneath the Calabrian Arc. The crustal thickness increases and reaches values between 28 and 30 km beneath the Tunisian coasts and Sicily Channel. The S-wave models reveal also the presence of high velocity body beneath the island of Sicily. This finding can be interpreted as the presence of the Ionian slab subducting beneath the Calabrian Arc. Another high velocity body is observed beneath the southern part of the Tyrrhenian basin, it might be interpreted as the presence of fragments of the African continental lithosphere beneath the  Tyrrhenian basin.

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 An Analysis of the Elements of an all Sky Survey

1985 ◽  
Vol 112 ◽  
pp. 405-410
Author(s):  
Edward T. Olsen ◽  
Anatoly Lokshin ◽  
Samuel Gulkis
Keyword(s):  
Observation Time ◽  
Frequency Resolution ◽  
Frequency Range ◽  
Broad Frequency Range ◽  
Sky Survey ◽  
Microwave Signals ◽  
Celestial Sphere

One component of the NASA search for microwave signals of extraterrestrial intelligent origin will be an all sky survey at a significantly low limiting flux over a broad frequency range. We are currently designing an overall strategy which will permit this survey to be: (1) carried out using existing antennas in less than 3 years of observation time, (2) uniform in sensitivity (within 0.5 db) over the celestial sphere for any given frequency, and (3) complete to 6×10−23 W/m2 or better over the frequency range 1.2GHz⩽ν⩽10GHz with a frequency resolution of 32 Hz.

scholarly journals High Velocity Flow Suggested by Wing Components of the Hα Line Profiles in the Selected Planetary Nebulae

2003 ◽  
Vol 209 ◽  
pp. 539-540
Author(s):  
S. Tamura ◽  
M. Otsuka ◽  
A. Tajitsu
Keyword(s):  
High Velocity ◽  
Gas Flow ◽  
Planetary Nebulae ◽  
Gas Flows ◽  
Stellar Winds ◽  
Short Report ◽  
Line Profiles ◽  
Internal Motions ◽  
Velocity Flow ◽  
Gaussian Method

This is a short report on the study of internal motions of selected Planetary nebulae. We have studied this subject with both high (4 or 8 Å/mm) and intermediate (20 Å/mm) dispersion spectrographs. During the course of this work we noticed the existence of a high velocity gas flow distinct from the well known expanding gas, but with smaller velocities than stellar winds (Yadoumaru & Tamura 1994 on Abell 30; Otsuka & Tamura, 2001 on H 4-1). We present subsequent results obtained with the intermediate dispersion spectrograph about 10 selected planetary nebulae. The analyses were made by multiple Gaussian method on the emission line profiles of Hα. High velocity gas flows were recognized by a weak broad wing component.

A Survey of Southern Compact and Bright Nucleus Galaxies

1984 ◽  
Vol 78 ◽  
pp. 397-399
Author(s):  
A.P. Fairall
Keyword(s):  
Seyfert Galaxies ◽  
Clusters Of Galaxies ◽  
Line Profiles ◽  
Compact Part ◽  
Sky Survey ◽  
Large Velocity ◽  
Compact Galaxies

During the 1960's, Zwicky made an intensive examination of the Palomar Sky Survey plates that resulted in his “Catalogue of Galaxies and of Clusters of Galaxies” (Zwicky et al. , 1961-1968). In the course of this study, he picked up numerous examples of what he labelled as “compact galaxies and compact parts of galaxies”; five lists were initially circulated and later presented as a catalogue (Zwicky 1971). To Zwicky the “compact” connotation suggested extremely high stellar densities, but line profiles failed to reveal the large velocity distributions expected of such concentrations of stars. Nevertheless an unexpected benefit was that many of his “compact parts” turned out to be the nuclei of actives galaxies, particularly Seyfert galaxies. Furthermore, since the nuclei have to stand out to gain “compact part” status, Seyfert nuclei from Zwicky’s lists tend to be fairly extreme specimens.

scholarly journals Statistical Study of High-Velocity Compact Clouds Based on the Complete CO Imagings of the Central Molecular Zone

2016 ◽  
Vol 11 (S322) ◽  
pp. 154-155 ◽  
Author(s):  
Sekito Tokuyama ◽  
Tomoharu Oka ◽  
Shunya Takekawa ◽  
Masaya Yamada ◽  
Yuhei Iwata ◽  
...  
Keyword(s):  
Spectral Line ◽  
High Velocity ◽  
Statistical Study ◽  
Complete List ◽  
Identification Procedure ◽  
Statistical Property ◽  
Gravitational Source ◽  
Large Velocity ◽  
Manual Selection ◽  
Automated Processes

High-velocity compact clouds (HVCCs) is one of the populations of peculiar clouds detected in the Central Molecular Zone (CMZ) of our Galaxy. They have compact appearances (< 5 pc) and large velocity widths (> 50 km s−1). Several explanations for the origin of HVCC were proposed; e.g., a series of supernovae (SN) explosions (Oka et al. 1999) or a gravitational kick by a point-like gravitational source (Oka et al. 2016). To investigate the statistical property of HVCCs, a complete list of them is acutely necessary. However, the previous list is not complete since the identification procedure included automated processes and manual selection (Nagai 2008). Here we developed an automated procedure to identify HVCCs in a spectral line data.

scholarly journals 9. New Spectroscopic Results on Subluminous Stars, V

1971 ◽  
Vol 42 ◽  
pp. 46-60 ◽  
Author(s):  
J. L. Greenstein
Keyword(s):  
High Velocity ◽  
Classification Scheme ◽  
Ultraviolet Excess ◽  
Horizontal Branch ◽  
Line Profiles ◽  
Hydrogen Line ◽  
Dwarf Stars ◽  
White Dwarf Stars ◽  
Halo Stars

Determination of temperature and surface gravity by colors and hydrogen-line profiles have been carried out for hot halo stars. A narrow horizontal branch is found stretching to above 40000 K; the hot O subdwarfs show a nearly vertical sequence, dropping towards the hot white dwarfs.Spectra for 285 white dwarf stars have been obtained, and the classification scheme is reviewed. Theoretical problems of these spectra remain, largely, unsolved.The red subluminous stars found by Eggen were studied spectroscopically; among 68 stars only one new red degenerate star was found. The others are very metal-poor, high-velocity stars with large ultraviolet excess.

Crust-mantle velocity structure in Shanxi rift, Central North China Craton

2020 ◽  
Author(s):  
Yan Cai ◽  
Jianping Wu
Keyword(s):  
Upper Mantle ◽  
High Velocity ◽  
North China Craton ◽  
Lower Crust ◽  
North China ◽  
Velocity Structure ◽  
Low Velocity ◽  
Crust And Upper Mantle ◽  
The North ◽  
Shanxi Rift

&lt;p&gt;North China Craton is the oldest craton in the world. It contains the eastern, central and western part. Shanxi rift and Taihang mountain contribute the central part. With strong tectonic deformation and intense seismic activity, its crust-mantle deformation and deep structure have always been highly concerned. In recent years, China Earthquake Administration has deployed a dense temporary seismic array in North China. With the permanent and temporary stations, we obtained the crust-mantle S-wave velocity structure in the central North China Craton by using the joint inversion of receiver function and surface wave dispersion. The results show that the crustal thickness is thick in the north of the Shanxi rift (42km) and thin in the south (35km). Datong basin, located in the north of the rift, exhibits large-scale low-velocity anomalies in the middle-lower crust and upper mantle; the Taiyuan basin and Linfen basin, located in the central part, have high velocities in the lower crust and upper mantle; the Yuncheng basin, in the southern part, has low velocities in the lower crust and upper mantle velocities, but has a high-velocity layer below 80 km. We speculate that an upwelling channel beneath the west of the Datong basin caused the low velocity anomalies there. In the central part of the Shanxi rift, magmatic bottom intrusion occurred before the tension rifting, so that the heated lithosphere has enough time to cool down to form high velocity. Its current lithosphere with high temperature may indicate the future deformation and damage. There may be a hot lithospheric uplift in the south of the Shanxi rift, heating the crust and the lithospheric mantle. The high-velocity layer in its upper mantle suggests that the bottom of the lithosphere after the intrusion of the magma began to cool down.&lt;/p&gt;

scholarly journals Properties of Lyα emitters at z≃6

2006 ◽  
Vol 2 (14) ◽  
pp. 253-253
Author(s):  
Crystal L. Martin ◽  
Marcin Sawicki ◽  
Alan Dressler ◽  
Patrick J. McCarthy
Keyword(s):  
Emission Line ◽  
Strong Evidence ◽  
Narrow Band ◽  
Narrow Band Imaging ◽  
Line Profiles ◽  
Galactic Winds ◽  
Line Survey

AbstractWe confirm the redshift of several z≃6 objects discovered by our imacs multislit emission-line survey. Their Lyα luminosities are lower than those of galaxies previously discovered using narrow-band imaging, as expected due to the excellent sky-supression inherent to this technique. Based on the line profiles of these objects, we argue that they are extremely young starbursts and find strong evidence for prominent galactic winds. This population of young galaxies is largely beyond the reach of current large surveys that use continuum selection.

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