Survey on Gaseous Nebula. Reporter: Jinjuan Liu 2004.12.29. Intense Diffuse Far-UV Emission from the Orion Nebula. Jayant Murthy David J. Sahnow and R. C. Henry. Observations and Data Analysis. FUSE was launched on June 24, 1999 into a low Earth orbit (LEO) by a Delta II rocket
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Reporter: Jinjuan Liu
Jayant Murthy David J. Sahnow and R. C. Henry
Fig. 1.— An interstellar dust map (Schlegel et al. 1998), with the Orion Nebula
(M42) in the center of the image.
Overplotted are the hot stars in Orionthe，
the star HD36981 :red circle at the NE edge of M42
Fig. 3.— Plotted are (from top to bottom) the FUSE spectrum of HD 36981, the Copernicus spectrum of Ori C and the FUSE observation reported here.
Fig. 2.— The spectrum for our diffuse observation is shown. Superimposed on the
plot is a scaled spectrum of Ori (red line) taken from the Copernicus archive.
The spectra shape is similar to the diffuse spectrum until the onset of interstellar Ly
absorption near 1200 °A.
--- in the case of HD 36981 due to self-absorption in the star and in the case of Ori C due to interstellar absorption in the several interstellar clouds in front of the Trapezium
---This is due to molecular hydrogen in both absorption and emission
--- in understanding the spectral properties of the interstellar dust
--- also in providing clues to the origin of
the diffuse emission.
Robert A. Gruendl and You-Hua ChuandMartı´n A. Guerrero
with FUSE(Far Ultraviolet Spectroscopic Explorer)
to search for Nebular O vi emission.
Fig.3 The bottom left panel shows the echellogram, and the bottom right shows the line profile extracted from the position marked by the horizontal dashed lines on the echellogram. The systemic velocity of NGC 6543 is marked by a dashed vertical line in each panel.
Fig. 4.—Results of the model calculation for the N-Cav observation of NGC6543 showing profiles for the temperature (top), electron density (middle), and O vi emissivity (bottom) as a function of distance from the inner wall of the nebular shell.
And T. Rauch
Fig. 1.—FUSE composite spectrum of PN G135.9+55.9 for the night-only exposure. A few of the strongest H i and O i k1025.76 airglow lines remain in
emission. The other features are absorption lines, most of which are due to interstellar matter. Molecular hydrogen lines are marked along the bottom of the
spectrum: the tick marks for the Lyman series lines are above those for the Werner series. Some other prominent interstellar lines of other elements are marked above
the spectrum. The rest positions of Ly and Ly are marked above the corresponding boxes.
Fig. 8.—Flux distribution of PN G 135.9+55.9 from far UV to near-IR. The open squares are the observed fluxes. The dashed lines are continuum fits to the observed data. Fluxes corrected for interstellar extinction are represented by filled squares . The dot-dashed line is the expected contribution from the nebula . The open circles are the extinction-corrected data after subtraction of the nebular component. The central star model with 120,000 K and log g =5.35 is presented as a
texp =Rout / vexp,
R out is the outer radius of the nebula and vexp is its expansion velocity
Fig. 1. R-band short-exposure mosaic of the northern Carina nebula region containing the clusters Tr 14 and Tr 16.
The circles mark the location and extension of the clusters Tr 14 and Tr 16 as derived from star counts.
Fig. 1.—Radial velocity channel maps of the 2.12 um H2 v=1–0 S(1) line emission in the Ring Nebula. LSR velocities in each channel are indicated in kilometers per second. The scale (in arcseconds) is given in the top left-hand panel. Maps show (in linear gray scale) the intensity of the H2 emission.. Crosses indicate the position of the central star. The noise level in all the images is constant, but the gray scale is varied in each
image to enhance the H2 emission.
Figure 3 shows a proposed model for the geometry of the H2 component of the Ring Nebula.
Fig. 4.—H2 integrated image of the Ring Nebula obtained from adding all the velocity channel maps. Labels indicate the position of the molecular knots detected in the velocity channels (see Table 2).
Fig. 5.—Profiles of the H2 v=1–0 S(1) line emission obtained at the positions shown in Fig. 4 and Table 2, with a spectral resolution of 24 km s-1. The line profiles are plotted on arbitrary scales that are not an indication of the relative intensities of the different lines.