A Search for Far-Ultraviolet Emission Lines from Diffuse Hot Gas in the Halo of NGC 4631

1995 ◽  
Vol 454 (1) ◽  
Author(s):  
Henry C. Ferguson ◽  
W. Van Dyke Dixon ◽  
Arthur F. Davidsen ◽  
Ralf-Juergen Dettmar
2002 ◽  
Vol 566 (2) ◽  
pp. 1100-1123 ◽  
Author(s):  
David R. Ardila ◽  
Gibor Basri ◽  
Frederick M. Walter ◽  
Jeff A. Valenti ◽  
Christopher M. Johns‐Krull

1999 ◽  
Vol 32 (15) ◽  
pp. 3813-3838 ◽  
Author(s):  
H Abgrall ◽  
E Roueff ◽  
Xianming Liu ◽  
D E Shemansky ◽  
G K James

Solar Physics ◽  
1967 ◽  
Vol 1 (2) ◽  
pp. 229-241 ◽  
Author(s):  
Andrea K. Dupree ◽  
Leo Goldberg

2004 ◽  
Vol 217 ◽  
pp. 147-153
Author(s):  
B. D. Savage ◽  
B. P. Wakker ◽  
K. R. Sembach ◽  
P. Richter ◽  
M. Meade

We summarize the results of the Far-Ultraviolet Spectroscopic Explorer (FUSE) program to study O VI in the Milky Way halo. Spectra of 100 extragalactic objects and two distant halo stars are analyzed to obtain measures of O VI absorption along paths through the Milky Way thick disk/halo and beyond. Strong O VI absorption over the velocity range from −100 to 100 km s−1 reveals a widespread but highly irregular distribution of O VI, implying the existence of substantial amounts of hot gas with T~3×105 K in the Milky Way thick disk/halo. The overall distribution of O VI can be described by a plane-parallel patchy absorbing layer with an average O VI mid-plane density of no(O VI) = 1.7×10−8 cm−3, an exponential scale height of ~2.3 kpc, and a ~0.25 dex excess of O VI in the northern Galactic polar region. Approximately 60 percent of the sky is covered by high velocity O VI with |vLSR|>100 km s−1. This high velocity O VI traces a variety of phenomena in and near the Milky Way including outflowing material from the Milky Way, tidal interactions with the Magellanic Clouds, accretion of gas onto the Milky Way, and warm/hot gas interactions in a highly extended (>70 kpc) Galactic corona or with hot intergalactic gas in the Local Group.


1978 ◽  
Vol 76 ◽  
pp. 121-122
Author(s):  
R.C. Bohlin ◽  
J.P. Harrington ◽  
T.P. Stecher

The ultraviolet emission lines that were me asured in the spectrum obtained from our rocket observation of NGC 7662 have been compared with those predicted by a set of models. The models allow a determination of the carbon abundance which is found to be solar and the C/0 ratio which is equal to unity. In order to obtain a good fit, dielectronic recombination and charge exchange between neutral hydrogen and C IV were included, both of which increase the concentration of C III. The observed continuum consists of light from the central star and from the nebula, which contributed primarily via the two photon process in the H° and the Balmer continuum.


2011 ◽  
Vol 7 (S283) ◽  
pp. 308-309 ◽  
Author(s):  
Luciana Bianchi ◽  
Arturo Manchado ◽  
Karl Forster

AbstractGALEX (the Galaxy Evolution Explorer) has provided far-UV(1344-1786Å) and near-UV(1771-2831Å) imaging of several Planetary Nebulae (e.g., Bianchi et al. 2008, Bianchi 2012), with flux limits ~27.5 mag/sq.arcsec for objects in the Medium-deph Imaging Survey (MIS). PNe images in the GALEX broad-band UV filters include flux from both nebular line and continuum emission. We use the GALEX grism observing mode to obtain slitless spectral imaging of a sample of PNe with diameters >1′, in the near-UV. We show the first data from this program. The grism produces 2D images of the prominent UV nebular emission lines, when such lines dominate the flux. Combined with monochromatic images of diagnostic lines in the optical domain, such data help detect and interpret ionization and shock fronts, especially in faint nebular regions.


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