Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Astronomers release most complete ultraviolet-light survey of nearby galaxies

18.05.2018

Capitalizing on the unparalleled sharpness and spectral range of NASA's Hubble Space Telescope, an international team of astronomers is releasing the most comprehensive, high-resolution ultraviolet-light survey of nearby star-forming galaxies.

The researchers combined new Hubble observations with archival Hubble images for 50 star-forming spiral and dwarf galaxies in the local universe, offering a large and extensive resource for understanding the complexities of star formation and galaxy evolution.


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/LEGUS team

The project, called the Legacy ExtraGalactic UV Survey (LEGUS), has amassed star catalogs for each of the LEGUS galaxies and cluster catalogs for 30 of the galaxies, as well as images of the galaxies themselves. The data provide detailed information on young, massive stars and star clusters, and how their environment affects their development.

"There has never before been a star cluster and a stellar catalog that included observations in ultraviolet light," explained survey leader Daniela Calzetti of the University of Massachusetts, Amherst.

"Ultraviolet light is a major tracer of the youngest and hottest star populations, which astronomers need to derive the ages of stars and get a complete stellar history. The synergy of the two catalogs combined offers an unprecedented potential for understanding star formation."

How stars form is still a vexing question in astronomy. "Much of the light we get from the universe comes from stars, and yet we still don't understand many aspects of how stars form," said team member Elena Sabbi of the Space Telescope Science Institute in Baltimore, Maryland. "This is even key to our existence -- we know life wouldn't be here if we didn't have a star around."

The research team carefully selected the LEGUS targets from among 500 galaxies, compiled in ground-based surveys, located between 11 million and 58 million light-years from Earth. Team members chose the galaxies based on their mass, star-formation rate, and abundances of elements that are heavier than hydrogen and helium. The catalog of ultraviolet objects collected by NASA's Galaxy Evolution Explorer (GALEX) spacecraft also helped lay the path for the Hubble study.

The team used Hubble's Wide Field Camera 3 and the Advanced Camera for Surveys over a one-year period to snap visible- and ultraviolet-light images of the galaxies and their most massive young stars and star clusters. The researchers also added archival visible-light images to provide a complete picture.

The star cluster catalogs contain about 8,000 young clusters whose ages range from 1 million to roughly 500 million years old. These stellar groupings are as much as 10 times more massive than the largest clusters seen in our Milky Way galaxy.

The star catalogs comprise about 39 million stars that are at least five times more massive than our Sun. Stars in the visible-light images are between 1 million and several billion years old; the youngest stars, those between 1 million and 100 million years old, shine prominently in ultraviolet light.

The Hubble data provide all of the information to analyze these galaxies, the researchers explained. "We also are offering computer models to help astronomers interpret the data in the star and cluster catalogs," Sabbi said. "Researchers, for example, can investigate how star formation occurred in one specific galaxy or a set of galaxies. They can correlate the properties of the galaxies with their star formation. They can derive the star-formation history of the galaxies. The ultraviolet-light images may also help astronomers identify the progenitor stars of supernovas found in the data."

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.

"When we look at a spiral galaxy, we usually don't just see a random distribution of stars," Calzetti said. "It's a very orderly structure, whether it's spiral arms or rings, and that's particularly true with the youngest stellar populations. On the other hand, there are multiple competing theories to connect the individual stars in individual star clusters to these ordered structures.

"By seeing galaxies in very fine detail -- the star clusters -- while also showing the connection to the larger structures, we are trying to identify the physical parameters underlying this ordering of stellar populations within galaxies. Getting the final link between gas and star formation is key for understanding galaxy evolution."

Team member Linda Smith of the European Space Agency (ESA) and the Space Telescope Science Institute added: "We're looking at the effects of the environment, particularly with star clusters, and how their survival is linked to the environment around them."

The LEGUS survey will also help astronomers interpret views of galaxies in the distant universe, where the ultraviolet glow from young stars is stretched to infrared wavelengths due to the expansion of space. "The data in the star and cluster catalogs of these nearby galaxies will help pave the way for what we see with NASA's upcoming infrared observatory, the James Webb Space Telescope, developed in partnership with ESA and the Canadian Space Agency (CSA)," Sabbi said.

Webb observations would be complementary to the LEGUS views. The space observatory will penetrate dusty stellar cocoons to reveal the infrared glow of infant stars, which cannot be seen in visible- and ultraviolet-light images. "Webb will be able to see how star formation propagates over a galaxy," Sabbi continued. "If you have information on the gas properties, you can really connect the points and see where, when, and how star formation happens."

###

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

For more information about LEGUS and Hubble, visit:

http://hubblesite.org/news_release/news/2018-27

http://www.nasa.gov/hubble

Donna Weaver / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4493 / 410-338-4514
dweaver@stsci.edu / villard@stsci.edu

Claire Saravia
NASA's Goddard Space Flight Center, Greenbelt, Maryland
301-286-1940
claire.g.desaravia@nasa.gov

Donna Weaver | idw - Informationsdienst Wissenschaft
Further information:
https://www.nasa.gov/feature/goddard/2018/astronomers-release-most-complete-UV-survey-of-nearby-galaxies

More articles from Physics and Astronomy:

nachricht ASU astrophysicist helps discover that ultrahot planets have starlike atmospheres
13.08.2018 | Arizona State University

nachricht UT-ORNL team makes first particle accelerator beam measurement in six dimensions
13.08.2018 | DOE/Oak Ridge National Laboratory

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

Im Focus: World record: Fastest 3-D tomographic images at BESSY II

The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.

Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends...

Im Focus: A molecular switch may serve as new target point for cancer and diabetes therapies

If certain signaling cascades are misregulated, diseases like cancer, obesity and diabetes may occur. A mechanism recently discovered by scientists at the Leibniz- Forschungsinstitut für Molekulare Pharmakologie (FMP) in Berlin and at the University of Geneva has a crucial influence on such signaling cascades and may be an important key for the future development of therapies against these diseases. The results of the study have just been published in the prestigious scientific journal 'Molecular Cell'.

Cell growth and cell differentiation as well as the release and efficacy of hormones such as insulin depend on the presence of lipids. Lipids are small...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

NRL's sun imaging telescopes fly on NASA Parker Solar Probe

13.08.2018 | Physics and Astronomy

UT-ORNL team makes first particle accelerator beam measurement in six dimensions

13.08.2018 | Physics and Astronomy

ASU astrophysicist helps discover that ultrahot planets have starlike atmospheres

13.08.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>