Archaeology / Cultural Heritage / History

[Archaeology] [twocolumns]

Anthropology / Human Evolution / Linguistics

[Anthropology] [twocolumns]

Palaeontology / Palaeoclimate / Earth Sciences

[Palaeontology] [twocolumns]

Evolution / Genetics / Biology

[Evolution][twocolumns]

Hubble shows the local universe in ultraviolet


Using the unparalleled sharpness and ultraviolet observational capabilities of the NASA/ESA Hubble Space Telescope, an international team of astronomers has created the most comprehensive high-resolution ultraviolet-light survey of star-forming galaxies in the local Universe. The catalogue contains about 8000 clusters and 39 million hot blue stars.

Hubble shows the local universe in ultraviolet
These six images represent the variety of star-forming regions in nearby galaxies. The galaxies are part of the Hubble
Space Telescope's Legacy ExtraGalactic UV Survey (LEGUS), the sharpest, most comprehensive ultraviolet-light
survey of star-forming galaxies in the nearby universe. The six images consist of two dwarf galaxies (UGC 5340
and UGCA 281) and four large spiral galaxies (NGC 3368, NGC 3627, NGC 6744, and NGC 4258). The images
 are a blend of ultraviolet light and visible light from Hubble's Wide Field Camera 3 and Advanced Camera
for Surveys [Credit: NASA, ESA, and the LEGUS team]
Ultraviolet light is a major tracer of the youngest and hottest stars. These stars are short-lived and intensely bright. Astronomers have now finished a survey called LEGUS (Legacy ExtraGalactic UV Survey) that captured the details of 50 local galaxies within 60 million light-years of Earth in both visible and ultraviolet light.

The LEGUS team carefully selected its targets from among 500 candidate galaxies compiled from ground-based surveys. They chose the galaxies based on their mass, star-formation rate, and their abundances of elements heavier than hydrogen and helium. Because of the proximity of the selected galaxies, Hubble was able to resolve them into their main components: stars and star clusters. With the LEGUS data, the team created a catalogue with about 8000 young clusters and it also created a star catalogue comprising about 39 million stars that are at least five times more massive than our Sun.

The data, gathered with Hubble's Wide Field Camera 3 and Advanced Camera for Surveys, provide detailed information on young, massive stars and star clusters, and how their environment affects their development. As such, the catalogue offers an extensive resource for understanding the complexities of star formation and galaxy evolution.

One of the key questions the survey may help astronomers answer is the connection between star formation and the major structures, such as spiral arms, that make up a galaxy. These structured distributions are particularly visible in the youngest stellar populations.

By resolving the fine details of the studied galaxies, while also studying the connection to larger galactic structures, the team aims to identify the physical mechanisms behind the observed distribution of stellar populations within galaxies.

Figuring out the final link between gas and star formation is key to fully understanding galaxy evolution. Astronomers are studying this link by looking at the effects of the environment on star clusters, and how their survival is linked to their surroundings.

LEGUS will not only allow astronomers to understand the local Universe. It will also help interpret views of distant galaxies, where the ultraviolet light from young stars is stretched to infrared wavelengths due to the expansion of space. The NASA/ESA/CSA James Webb Space Telescope and its ability to observe in the far infrared will complement the LEGUS views.

Source: ESA/Hubble Information Centre [May 17, 2018]

TANN

Post A Comment
  • Blogger Comment using Blogger
  • Facebook Comment using Facebook
  • Disqus Comment using Disqus

No comments :


Exhibitions / Travel

[Exhibitions] [bsummary]

Natural Heritage / Environment / Wildlife

[Natural Heritage] [list]

Astronomy / Astrobiology / Space Exploration

[Universe] [list]