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.

A Flash in the Dark: UVES Very Large Telescope High‐Resolution Spectroscopy of Gamma‐Ray Burst Afterglows

2005 ◽  
Vol 624 (2) ◽  
pp. 853-867 ◽  
Author(s):  
F. Fiore ◽  
V. D’Elia ◽  
D. Lazzati ◽  
R. Perna ◽  
L. Sbordone ◽  
...  
Keyword(s):  
High Resolution ◽  
Gamma Ray ◽  
High Resolution Spectroscopy ◽  
Large Telescope ◽  
Gamma Ray Burst ◽  
Very Large Telescope

High Resolution Spectroscopy of Absorption Lines in the Z = 1.7 BL LAC Object 0215+015

Quasars ◽  
1986 ◽  
pp. 571-572
Author(s):  
J. Chris Blades ◽  
Richard W. Hunstead ◽  
Hugh S. Murdoch ◽  
Max Pettini
Keyword(s):  
High Resolution ◽  
Absorption Lines ◽  
High Resolution Spectroscopy ◽  
Bl Lac

scholarly journals Lithium abundance in lower red giant branch stars of Omega Centauri

2018 ◽  
Vol 618 ◽  
pp. A134 ◽  
Author(s):  
A. Mucciarelli ◽  
M. Salaris ◽  
L. Monaco ◽  
P. Bonifacio ◽  
X. Fu ◽  
...  
Keyword(s):  
High Resolution ◽  
Globular Clusters ◽  
Stellar System ◽  
The Other ◽  
Large Telescope ◽  
Lithium Abundance ◽  
Very Large Telescope ◽  
Red Giant ◽  
Giant Branch Stars ◽  
Branch Star

We present Li, Na, Al, and Fe abundances of 199 lower red giant branch star members of the stellar system Omega Centauri, using high-resolution spectra acquired with FLAMES at the Very Large Telescope. The A(Li) distribution is peaked at A(Li) ∼ 1 dex with a prominent tail towards lower values. The peak of the distribution well agrees with the lithium abundances measured in lower red giant branch stars in globular clusters and Galactic field stars. Stars with A(Li) ∼ 1 dex are found at metallicities lower than [Fe/H] ∼ –1.3 dex but they disappear at higher metallicities. On the other hand, Li-poor stars are found at all metallicities. The most metal-poor stars exhibit a clear Li–Na anti-correlation, where about 30% of the sample have A(Li) lower than ∼0.8 dex, while these stars represent a small fraction of normal globular clusters. Most of the stars with [Fe/H] > –1.6 dex are Li poor and Na rich. The Li depletion measured in these stars is not observed in globular clusters with similar metallicities and we demonstrate that it is not caused by the proposed helium enhancements and/or young ages. Hence, these stars formed from a gas already depleted in lithium. Finally, we note that Omega Centauri includes all the populations (Li-normal/Na-normal, Li-normal/Na-rich, and Li-poor/Na-rich stars) observed, to a lesser extent, in mono-metallic GCs.

scholarly journals IGRINS NEAR-IR HIGH-RESOLUTION SPECTROSCOPY OF MULTIPLE JETS AROUND LkHα234

2016 ◽  
Vol 817 (2) ◽  
pp. 148 ◽  
Author(s):  
Heeyoung Oh ◽  
Tae-Soo Pyo ◽  
In-Soo Yuk ◽  
Byeong-Gon Park ◽  
Chan Park ◽  
...  
Keyword(s):  
High Resolution ◽  
High Resolution Spectroscopy ◽  
Near Ir ◽  
Multiple Jets

scholarly journals Very high-resolution spectroscopy for extremely large telescopes using pupil slicing and adaptive optics

2007 ◽  
Vol 15 (5) ◽  
pp. 1983 ◽  
Author(s):  
Jacques M. Beckers ◽  
Torben E. Andersen ◽  
Mette Owner-Petersen
Keyword(s):  
High Resolution ◽  
Adaptive Optics ◽  
High Resolution Spectroscopy ◽  
Large Telescopes ◽  
Very High

scholarly journals Summary – A Personal View

1998 ◽  
Vol 11 (2) ◽  
pp. 689-691
Author(s):  
Kazimierz StȩpieŃ
Keyword(s):  
Large Telescope ◽  
Personal View ◽  
Very Large Telescope ◽  
The Subject ◽  
The Right ◽  
Large Telescopes

Let me first remind you of the subject of the present Joint Discussion. It is about spectroscopy with large telescopes. As I have never done any spectroscopic research of my own and I have never observed with a very large telescope, I am certainly the right person to summarize the most recent results in this area.

scholarly journals White dwarf pollution by hydrated planetary remnants: hydrogen and metals in WD J204713.76–125908.9

2020 ◽  
Vol 499 (1) ◽  
pp. 171-182
Author(s):  
Matthew J Hoskin ◽  
Odette Toloza ◽  
Boris T Gänsicke ◽  
Roberto Raddi ◽  
Detlev Koester ◽  
...  
Keyword(s):  
Water Mass ◽  
Hubble Space Telescope ◽  
Parent Body ◽  
Absorption Lines ◽  
Carbonaceous Chondrites ◽  
Large Telescope ◽  
Volatile Elements ◽  
Very Large Telescope ◽  
Far Ultraviolet ◽  
Cosmic Origin

ABSTRACT WD J204713.76–125908.9 is a new addition to the small class of white dwarfs with helium-dominated photospheres that exhibit strong Balmer absorption lines and atmospheric metal pollution. The exceptional abundances of hydrogen observed in these stars may be the result of accretion of water-rich rocky bodies. We obtained far-ultraviolet and optical spectroscopy of WD J204713.76–125908.9 using the Cosmic Origin Spectrograph on-board the Hubble Space Telescope and X-shooter on the Very Large Telescope, and identify photospheric absorption lines of nine metals: C, O, Mg, Si, P, S, Ca, Fe, and Ni. The abundance ratios are consistent with the steady-state accretion of exo-planetesimal debris rich in the volatile elements carbon and oxygen, and the transitional element sulphur, by factors of 17, 2, and 4, respectively, compared to the bulk Earth. The parent body has a composition akin to Solar system carbonaceous chondrites, and the inferred minimum mass, 1.6 × 1020 g, is comparable to an asteroid 23 km in radius. We model the composition of the disrupted parent body, finding from our simulations a median water mass fraction of 8 per cent.

scholarly journals Sizes of Intervening C IV Absorbers from High Resolution Spectroscopy of APM 0827+5255

2004 ◽  
Vol 217 ◽  
pp. 272-274
Author(s):  
Panayiotis Tzanavaris ◽  
Robert F. Carswell
Keyword(s):  
High Resolution ◽  
Lower Limit ◽  
Absorption Lines ◽  
High Resolution Spectroscopy ◽  
Line Of Sight ◽  
Total Coverage ◽  
Best Estimates

Some intervening C IV absorbers in the Keck/HIRES spectrum of APM 0827+5255 give rise to absorption lines for which the observed optical depths for the doublet components are not in the expected 2 : 1 ratio. We model this effect as coverage of one line of sight to this gravitationally lensed quasar and perform a set of simulations to select a sample of lines for which our model provides an explanation for the effect. We use lines in this sample to obtain estimates for minimum absorber sizes from total coverage and the separations of the lines of sight for a range of lens redshifts, z1, and two cosmologies. We also obtain best estimates for overall sizes from a statistical “hit and miss” approach. For z1 = 0.7 our results set a lower limit to sizes of C IV absorbers of ~ 0.3 h−172 kpc (~ 0.5 h−172 kpc) for ΩM = 1, ΩA = 0 (ΩM = 0.3, ΩA = 0.7).

Sign in / Sign up

Export Citation Format

Share Document