scholarly journals HERMES – An instrument of the future

2009 ◽  
Vol 5 (S262) ◽  
pp. 448-449 ◽  
Author(s):  
Elizabeth Wylie-de Boer ◽  
Kenneth Freeman

AbstractHERMES is a new, multi-object high resolution spectrometer for the 3.9m Anglo Australian Telescope, using the existing 2dF positioner. The primary goal of the HERMES survey is to unravel the history of the Galaxy from detailed elemental abundances for about 1.2 million individual stars. The HERMES chemical tagging survey concentrates on the 5000 to 8000 Å window at a resolving power of 30,000 in order to identify dissolved star formation aggregates and ascertain the importance of mergers throughout the history of the Galaxy.

2003 ◽  
Vol 208 ◽  
pp. 431-432
Author(s):  
N. Nakasato

In the current most plausible Cold Dark Matter (CDM) cosmology, larger halos increase their mass by the progressive mergers of smaller clumps. Due to these progressive merger events, galaxies have formed and evolved. Such merger events could trigger star bursts depending on mass of a merging object. In other words, star formation history reflects the strength of the interaction between a galaxy and merging objects. Also, a several merger events strongly affect the development of the morphology of galaxies as assumed in semi-analytic models. In the most advanced semi-analytic models, N-body simulations of dark matter particles are used to obtain the merging history of halos. By combining the description of radiative cooling, hydrodynamics and star formation with the obtained merging history, such models successfully have explained the various qualitative predictions. Here, we show the results of similar approach but using a fullly numerical model. In contrast to the semi-analytic models, we use our high resolution Smoothed Particle Hydrodynamics (SPH) models. With our SPH code, we try to tackle the problem of the galaxy morphology. We have done a several handful high-resolution SPH simulations and analyzed the merging history of such models. Accordingly, we can see the relation between the obtained morphology and the merging history or other physical properties of the model.


2018 ◽  
Vol 25 (3) ◽  
pp. 738-747 ◽  
Author(s):  
Zhuo Li ◽  
Bin Li

The authors report a novel scheme for a grazing-incidence spectrometer forming an excellent meridional flat field in its detector domain to deliver the desired spectral resolution throughout the full designated spectral range, while reducing the sagittal astigmatism substantially to enhance the spectral intensity. The optical properties of the system are thoroughly investigated and optimized, and the detector plane is fitted well to the meridional or sagittal focal curves. The authors demonstrated that a resolving power of 6000–18000 could be achieved within the `water window' (2–5 nm) for an effective meridional source size of 200 µm (r.m.s.), and it would be further improved to 20000–40000 if the source size was confined to 50 µm (r.m.s.).


2021 ◽  
Vol 169 ◽  
pp. 112460
Author(s):  
R. Luís ◽  
Y. Nietiadi ◽  
A. Silva ◽  
B. Gonçalves ◽  
T. Franke ◽  
...  

1967 ◽  
Vol 54 (1) ◽  
pp. 71-76 ◽  
Author(s):  
R.J. Sutter ◽  
G. Bennett ◽  
J. Fischer ◽  
J.L. Friedes ◽  
H. Palevsky ◽  
...  

2008 ◽  
Vol 53 (9(4)) ◽  
pp. 2307-2311
Author(s):  
Yun-Fei Wu ◽  
Qing-Yuan Cai ◽  
Yu-Xiang Zheng ◽  
Rong-Jun Zhang ◽  
Liang-Yao Chen

2008 ◽  
Vol 4 (S256) ◽  
pp. 281-286
Author(s):  
Carme Gallart ◽  
Ingrid Meschin ◽  
Antonio Aparicio ◽  
Peter B. Stetson ◽  
Sebastián L. Hidalgo

AbstractBased on the quantitative analysis of a set of wide-field color—magnitude diagrams reaching the old main sequence-turnoffs, we present new LMC star-formation histories, and their variation with galactocentric distance. Some coherent features are found, together with systematic variations of the star-formation history among the three fields analyzed. We find two main episodes of star formation in all three fields, from 1 to 4 and 7 to 13 Gyr ago, with relatively low star formation around ≃ 4–7 Gyr ago. The youngest age in each field gradually increases with galactocentric radius; in the innermost field, LMC 0514–6503, an additional star formation event younger than 1 Gyr is detected, with star formation declining, however, in the last ≃ 200 Myr. The population is found to be older on average toward the outer part of the galaxy, although star formation in all fields seems to have started around 13 Gyr ago.


Sign in / Sign up

Export Citation Format

Share Document