scholarly journals Fabry-Perot Images of Ionised and Molecular Hydrogen in Sgr A

1989 ◽  
Vol 136 ◽  
pp. 411-416
Author(s):  
D. L Depoy ◽  
Ian Gatley ◽  
I. S. Mclean
Keyword(s):  
Spatial Resolution ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Gamma Line ◽  
Fabry Perot ◽  
The Galaxy ◽  
Sgr A

Images of the central 36 arcseconds of the Galaxy in the Brackett gamma line of atomic hydrogen (2.17μm) at a spatial resolution of 0.6 arcsec and a velocity resolution of 110 km/sec were obtained using UKIRT. The velocity separation between adjacent frames is 55 km/sec; 17 different velocities channels were imaged. Several distinct kinematic components are evident within the clumpy distribution of the ionised gas. An image in the v=1-0 S(1) line of molecular hydrogen (2.12μm) clearly resolves the structure of the “molecular ring.”

A CO Survey of the Southern Galactic Plane

1981 ◽  
Vol 4 (2) ◽  
pp. 243-247 ◽  
Author(s):  
W. H. McCutcheon ◽  
B. J. Robinson ◽  
J. B. Whiteoak
Keyword(s):  
Northern Hemisphere ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Large Scale ◽  
Galactic Plane ◽  
Galactic Centre ◽  
Hydrogen Distribution ◽  
Millimetre Wave ◽  
The Galaxy ◽  
Wave Emission

Millimetre-wave emission from the CO molecule has proven to be an extremely useful probe of the cold, dense clouds of molecular hydrogen in the Galaxy. Previous studies of the large-scale distribution of CO in the galactic plane (Scoville and Solomon 1975; Burton et al. 1975; Bash and Peters 1976; Burton and Gordon 1978; Solomon et al. 1979b; Cohen et al. 1980) have all been of the northern hemisphere and primarily at longitudes 0° ≤ l ≥ 80°. These studies have revealed the striking characteristic that the CO, and by implication molecular hydrogen clouds, are concentrated in a ring extending from 4 to 8 kpc from the galactic centre. This is in sharp contrast to the atomic hydrogen distribution, which is fairly constant over the extended region from 4 to 13 kpc but correlates well with other Population I indicators.

scholarly journals 7.2. 12.5μ imaging of Sgr A West with the Keck Telescope

1998 ◽  
Vol 184 ◽  
pp. 293-294
Author(s):  
E. E. Becklin ◽  
M. Morris ◽  
D. F. Figer ◽  
A. M. Ghez ◽  
R. Puetter ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Central Region ◽  
Angular Resolution ◽  
Diffraction Limit ◽  
Mosaic Pattern ◽  
Long Wavelength ◽  
The Galaxy ◽  
Sgr A ◽  
Better Than ◽  
Atmospheric Seeing

We have used the 10-meter Keck I telescope and the camera mode of the long wavelength spectrometer to observe the central region of the Galaxy at 12.5 μm. The 96×70 As:Si array used had a scale of 0.114 arcsec per pixel. The filter was centered at 12.5 μm and had a bandwidth of about 1 μm. The array was flat-fielded using sky flats from the background. We observed the central 20×20 arcsec region (about 1pc × 1pc) by using a mosaic pattern of the 11×8 arcsec array in approximately half-array steps. The position of the array was determined after the fact by using structure in the flux in the overlap regions. The accuracy of the positioning was better than 0.1 arcsec. The resultant spatial resolution of the final map was about 0.7 arcsec FWHM based on the size of IRS 7 and IRS 3. The demonstrated diffraction limit of the phased Keck telescope at 12.5 microns is just over 0.3 arcsec FWHM, so that the final resolution is a result of atmospheric seeing and chopper smear. The final map is shown in Figure 1. The map is similar, but of much higher angular resolution, to the 12.5 μm map of Gezari (1992, The Center, Bulge and Disk of the Galaxy, ed. Blitz, Dordrecht: Kluwer, 23).

scholarly journals Line observations of the 30-Dor complex and N159A5 with the MPE imaging NIR spectrometer FAST

1991 ◽  
Vol 148 ◽  
pp. 205-206 ◽  
Author(s):  
A. Krabbe ◽  
J. Storey ◽  
V. Rotaciuc ◽  
S. Drapatz ◽  
R. Genzel
Keyword(s):  
Spatial Resolution ◽  
Molecular Hydrogen ◽  
Near Infrared ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Emission Lines ◽  
Resolving Power ◽  
Max Planck ◽  
First Time ◽  
Infrared Array

Images with subarcsec spatial resolution in the light of near-infrared atomic (Bry) and molecular hydrogen H2 (S(1) v=1-0) emission lines were obtained for some extended, pointlike objects in the Large Magellanic Cloud (LMC) for the first time. We used the Max-Planck-Institut für extraterrestrische Physik (MPE) near-infrared array spectrometer FAST (image scale 0.8”/pix, spectral resolving power 950) at the ESO/MPI 2.2m telescope, La Silla. We present some results on the 30-Dor complex and N159A5.

Further investigations of charge exchange and electron detachment - I. Ion energies 3 to 40 keV - II. Ion energies 100 to 4000 eV

1955 ◽  
Vol 227 (1171) ◽  
pp. 466-486 ◽  
Keyword(s):  
Charge Transfer ◽  
Energy Range ◽  
Cross Sections ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Hydrogen Ions ◽  
Electron Detachment ◽  
Rare Gases ◽  
Helium Ions ◽  
Ion Energies

This paper describes the measurement of charge transfer cross-sections for protons, molecular hydrogen ions and helium ions in the rare gases and hydrogen, and electron detachment cross-sections for negative atomic hydrogen ions in the rare gases. Part I describes the energy range 3 to 40 keV. In part II the energy range 100 to 4000 eV is described, and the results are discussed in terms of the pseudo-adiabatic hypothesis. Comparisons are made with other experimental results, and anomalous molecular cases are discussed in terms of reactions involving anti-bonding states.

Formation of metastable atomic hydrogen in the 2sstate from symmetry-resolved doubly excited states of molecular hydrogen

2011 ◽  
Vol 84 (5) ◽  
Author(s):  
Takeshi Odagiri ◽  
Yoshiaki Kumagai ◽  
Motoyoshi Nakano ◽  
Takehiko Tanabe ◽  
Isao H. Suzuki ◽  
...  
Keyword(s):  
Excited States ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Doubly Excited States ◽  
Doubly Excited

Hydrogen escape from Mars is driven by seasonal and dust storm transport of water

Science ◽  
2020 ◽  
Vol 370 (6518) ◽  
pp. 824-831
Author(s):  
Shane W. Stone ◽  
Roger V. Yelle ◽  
Mehdi Benna ◽  
Daniel Y. Lo ◽  
Meredith K. Elrod ◽  
...  
Keyword(s):  
Dust Storm ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Dust Storms ◽  
Upper Atmosphere ◽  
Lower Atmosphere ◽  
Mars Atmosphere ◽  
Water Abundance ◽  
Neutral Gas ◽  
Standard Models

Mars has lost most of its once-abundant water to space, leaving the planet cold and dry. In standard models, molecular hydrogen produced from water in the lower atmosphere diffuses into the upper atmosphere where it is dissociated, producing atomic hydrogen, which is lost. Using observations from the Neutral Gas and Ion Mass Spectrometer on the Mars Atmosphere and Volatile Evolution spacecraft, we demonstrate that water is instead transported directly to the upper atmosphere, then dissociated by ions to produce atomic hydrogen. The water abundance in the upper atmosphere varied seasonally, peaking in southern summer, and surged during dust storms, including the 2018 global dust storm. We calculate that this transport of water dominates the present-day loss of atomic hydrogen to space and influenced the evolution of Mars’ climate.

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