Interstellar absorption lines in the infrared spectrum of NGC 2024 IRS 2

1984 ◽  
Vol 279 ◽  
pp. 673 ◽  
Author(s):  
J. H. Black ◽  
S. P. Willner
Keyword(s):  
Infrared Spectrum ◽  
Absorption Lines ◽  
Interstellar Absorption

scholarly journals 10. Radio observations of interstellar neutral hydrogen clouds

1957 ◽  
Vol 4 ◽  
pp. 66-66
Author(s):  
R. S. Lawrence
Keyword(s):  
Angular Resolution ◽  
Neutral Hydrogen ◽  
Optical Component ◽  
Absorption Lines ◽  
Radio Observations ◽  
Interstellar Absorption ◽  
Peak Intensity

The detailed relationship between optical interstellar absorption lines and 21-cm. observations is investigated in this paper.Dr Guido Münch, of the Mount Wilson and Palomar Observatories, provided the list of six intermediate-latitude stars shown in Table 1. The spectra of these stars all show complex absorption lines due to interstellar Ca 11. The 21-cm. line is measurable in four of the six regions, although the peak intensity is low in each case. It is noteworthy that for the first two stars on the list the radio velocity agrees closely with the velocity of an intense optical component. In view of the great difference in angular resolution, the failure to find correspondence in every case is not surprising.

Interstellar absorption lines in the spectrum of 3C 273

1983 ◽  
Vol 274 ◽  
pp. 136 ◽  
Author(s):  
D. G. York ◽  
C. C. Wu ◽  
J. C. Blades ◽  
S. Ratcliff ◽  
L. L. Cowie ◽  
...  
Keyword(s):  
Absorption Lines ◽  
Interstellar Absorption

Interstellar absorption lines in the galaxy NGC 1705

1990 ◽  
Vol 351 ◽  
pp. 412 ◽  
Author(s):  
D. G. York ◽  
A. Caulet ◽  
P. Rybski ◽  
J. Gallagher ◽  
J. C. Blades ◽  
...  
Keyword(s):  
Absorption Lines ◽  
Interstellar Absorption ◽  
The Galaxy

scholarly journals The Mg II Features Near 2800Å and Spectral Classification

1977 ◽  
Vol 4 (2) ◽  
pp. 363-364
Author(s):  
Yoji Kondo
Keyword(s):  
The Other ◽  
Absorption Lines ◽  
Spectral Features ◽  
The Sun ◽  
Spectral Classification ◽  
Interstellar Absorption ◽  
B Stars ◽  
The Core ◽  
Chromospheric Emission

The Mg II resonance lines at 2795.523 and 2802.698Å and their respective subordinate lines at 2797.989 and 2790.768Å are probably among the most prominent and interesting spectral features in the ultraviolet; they are perhaps the most significant in the mid-ultraviolet. They are also observable in one form or the other in stars of practically all spectral types. We shall discuss relatively high (about 0.4Å) resolution observations of these features.In the early spectral types both the resonance and subordinate lines are seen primarily as absorption lines. An interstellar absorption of varying strengths is superimposed on the photospheric absorption of the resonance lines. The strengths of the photospheric resonance and subordinate lines increase from 0 to B, e.g., Lamers et al. (1973) and Kondo et al. (1975). The subordinate lines begin to merge with the resonance lines in late-B stars. In mid-A type stars, the resonance and subordinate absorption strengths become maximum. In F-type stars, the photospheric absorption strenghts continue to decrease. Chromospheric emissions become definitely detectable in F-type stars (Kondo et al. 1972). In a G2 V star, the sun, the chromospheric emission is fairly prominent at the core of relatively weak photospheric absorption. In K and M-type stars, this region is presumably dominated by the chromospheric emissions of Mg II resonance lines with the photospheric absorption becoming negligible in late-K stars; the only extant observation in this region is that of e Eri (K2 V) (McClintock et al. 1975).

Rapid Temporal Variations of Interstellar Absorption Lines in the Carina Nebula

2001 ◽  
Vol 547 (2) ◽  
pp. L155-L159 ◽  
Author(s):  
Anthony C. Danks ◽  
Nolan R. Walborn ◽  
Gladys Vieira ◽  
Wayne B. Landsman ◽  
Joel Gales ◽  
...  
Keyword(s):  
Temporal Variations ◽  
Absorption Lines ◽  
Interstellar Absorption ◽  
Carina Nebula

scholarly journals Interstellar Matter with Very Large Telescopes

1984 ◽  
Vol 79 ◽  
pp. 675-678
Author(s):  
J. Lequeux
Keyword(s):  
High Resolution ◽  
Absorption Lines ◽  
High Resolution Spectroscopy ◽  
Interstellar Matter ◽  
Large Telescope ◽  
Interstellar Absorption ◽  
Near Ir ◽  
Very Large Telescope ◽  
Large Telescopes ◽  
Diffuse Matter

Interstellar matter is certainly one of the fields where a very large telescope (VLT) will prove to be most fruitful. This includes (somewhat paradoxically, but this will be explained later) the study of extended emissions. I will now examine in turn the different domains of interest for a VLT.I. Neutral diffuse matterOptical and near IR observations will mainly contribute to this domain through high-resolution spectroscopy of interstellar absorption lines in the spectra of stars. These lines are resonant lines of atoms (NaI, KI, etc.) or ions (CaII, TiII, etc.) as well as of some molecules (CH+, CH, CN, CS+, C2 in the near IR). Clearly this kind of study is always photon - limited; a VLT will collect more photons than present telescopes, thus increase the possibilities considerably.

scholarly journals Atomic and Molecular Interstellar Absorption Lines toward the High Galactic Latitude Stars HD 141569 and HD 157841 at Ultra–High Resolution

1998 ◽  
Vol 504 (1) ◽  
pp. 522-532 ◽  
Author(s):  
M. S. Sahu ◽  
J. C. Blades ◽  
L. He ◽  
Dap Hartmann ◽  
M. J. Barlow ◽  
...  
Keyword(s):  
High Resolution ◽  
Absorption Lines ◽  
Galactic Latitude ◽  
High Galactic Latitude ◽  
Interstellar Absorption
Sign in / Sign up

Export Citation Format

Share Document