There is often dust associated with ionized regions. Compact HII regions usually have associated dust from a molecular cloud in which the massive star is being "born". ... For such stars the dust is not produced by the star, and a variety of dust features are observed. The planetary nebulae also usually have associated dust from the previous stage of evolution where they were either carbon stars or M-type giants. ... The feature near 11.5 microns in the IC 418 spectrum may be due to SiC dust. ...

Next: Radial velocity of the Up: Optical spectrum of IRAS04296 Previous: Observations and spectra reduction . ... However, molecular emission features are only very rarely observed in the optical spectra of PPNe. ... On the other hand, it is well known that cometary nuclei spectra show prominent Swan band emission. In both spectra of IRAS04296 we have discovered strong emission in the (0;0) and (0;1) bands of the Swan system of the molecule. ... Now consider the case of IRAS04296. ...

... Science . ... Science Users Information > Data Handling and Products > Data Reduction FAQ > The response curve leaves residual instrument features in my science. ... Observing Facilities . ... Observing with ESO Telescopes . ... Science Data Products Forum . ... Science Archive Facility . ... ESO Data . ... ESO Data Access Policy . ... ESO Science Newsletter . ... To can be avoided by flat-fielding the flux standard star spectrum with the same flat field as is used for the science data. ...

... The J, H and K bands are characterized by a bright background, such a background is mainly due to the emission of atmospheric lines and of thermal radiation. ... If the source cover a large fraction of the slit, spectra off-source must be observed to adequately sample the sky background. ... The on chip integration time (time spent in each position of the slit) must not exceed 40 seconds in J and H bands and 60 seconds in K band. ... We suggest a sequence of 10 for each elementary integration time. ...

Next: Amorphous magnesium silicate Up: Examples of data contained Previous: Examples of data contained . ... We have used the infrared optical constants of forsterite contained in the database for calculating the absorption cross sections of spherical and non-spherical particles in the Rayleigh limit (see Fig. The spectra are obtained by averaging the cross sections calculated for the three different crystallographic directions. ...

... HOME . ... Richard J. Edgar, Project Scientist . DXS, the Diffuse X-ray Spectrometer instruments were flown on the STS-54 mission of the Space Shuttle Endeavour in January of 1993. ... A Summary of the First Results from the Diffuse X-ray Spectrometer Experiment . ... In January of 1993 the Diffuse X-ray Spectrometer (DXS) instruments flew on the STS-54 mission of the Space Shuttle Endeavour. ... The DXS x-ray spectrum from the diffuse background in the constellations of Puppis and Auriga. ...

We present broadband photometry in the optical, near infrared and sub-millimetre, and mid-infrared spectrophotometry of a selection of carbon stars with optically thin envelopes. ... Beside the emission features at 11.3 \mu m due to silicon carbide grains in the circumstellar environment, many of our mid-infrared spectra show an emission feature at 8.6 \mu m. All the observed spectral energy distributions exhibit a very large far-infrared flux excess. ...

Ground-Based Mid Infra-Red Observations of Nearby Starburst and AGN Galaxies Bo jan Nikolic , Paul Alexander, Garret Cotter and Malcolm Longair Astrophysics Group, Cavendish Lab, Cambridge, U.K. Marcel Clemens Universita degli Studi di Padova, Italy Abstract. We present preliminary results of recent spatially resolved mid infrared (Mid-IR) spectroscopy with the MICHELLE instrument on UKIRT of NGC 7469, observed as part of a larger programme to study a sample of starburst and AGN in the Mid-IR. ...

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