#Legacy ExtraGalactic UV Survey

[gepetordi1]

The galaxy known as NGC 1433 is a type of very active galaxy known as a Seyfert galaxy — a classification that accounts for only 10% of all galaxies. They have very bright, luminous centers that are comparable in brightness to that of our entire galaxy.

NGC 1433 is being studied as part of a survey of 50 nearby galaxies known as the Legacy ExtraGalactic UV Survey (LEGUS). Ultraviolet radiation is observed from galaxies, mainly tracing the most recently formed stars. In Seyfert galaxies, ultraviolet light is also thought to emanate from the accretion discs around their central black holes. Studying these galaxies in the ultraviolet part of the spectrum is incredibly useful to study how the gas is behaving near the black hole.

[wigmund]

From SpaceTelescope.Org Picture of the Week; June 19, 2017:

Surveying The Cosmos

The object in the middle of this image, sitting alone within a star-studded cosmos, is a galaxy known as ESO 486-21. ESO 486-21 is a spiral galaxy — albeit with a somewhat irregular and ill-defined structure — located some 30 million light-years from Earth.

The NASA/ESA Hubble Space Telescope observed this object while performing a survey — the Legacy ExtraGalactic UV Survey (LEGUS) — of 50 nearby star-forming galaxies. The LEGUS sample was selected to cover a diverse range of galactic morphologies, star formation rates, galaxy masses, and more. Astronomers use such data to understand how stars form and evolve within clusters, and how these processes affect both their home galaxy and the wider Universe. ESO 486-21 is an ideal candidate for inclusion in such a survey as it is known to be in the process of forming new stars, which are created when large clouds of gas and dust (seen here in pink) within the galaxy crumple inwards upon themselves.

LEGUS made use of Hubble’s Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS). The WFC3 obtained detailed observations of the target objects while the ACS obtained what are known as parallel fields — instead of leaving ACS idle, it was instead trained on a small patch of sky just offset from the target field itself, allowing it to gather additional valuable information while the primary target was being observed by WFC3. Parallel fields played an important role in Hubble’s Frontier Fields programme, which used the magnifying power of large galaxy clusters (via a phenomenon known as gravitational lensing) to explore objects in the distant Universe.

Credit: ESA/Hubble & NASA

[space--bot]

Hubble contributes to painting a picture of the evolving Universe

The Hubble Deep Field from 1995 allowed astronomers a first glimpse into the early Universe. This first picture was followed later by an even deeper observation, the Hubble Ultra Deep Field in 2004. Both images were observed in visible light, the same form of light human eyes can see. But astronomers are also interested in the many forms of invisible light out in the Universe. Therefore, the Ultra Deep Field was later observed in the infrared and the ultraviolet as well, allowing scientists to learn even more about the Universe and to look back even further into its history.

It is less known that the famous deep field observations were not the only images the NASA/ESA Hubble Space Telescope took of the distant Universe. Hubble is also an essential part of the GOODS (The Great Observatories Origins Deep Survey) programme, which unites extremely deep observations from several space telescopes: NASA’s Spitzer and Chandra; ESA's Herschel and XMM-Newton; and Hubble.

Together these observatories observe two patches of the sky, the GOODS North and the GOODS South fields, with the aim of studying it in as many different wavelengths as possible. The new image here shows part of the GOODS North Field; it includes new Hubble data at ultraviolet wavelengths in addition to the existing data. Because Earth’s atmosphere filters out most ultraviolet light, these observations can only be accomplished from space.

The observation programme, called the Hubble Deep UV (HDUV) Legacy Survey, harnessed the ultraviolet vision of Hubble’s Wide Field Camera 3. This study extends and builds on the previous Hubble multi-wavelength data in the CANDELS-Deep (Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey) fields within the central part of the GOODS (The Great Observatories Origins Deep Survey) fields. This mosaic is 14 times the area of the Hubble Ultraviolet Ultra Deep Field released in 2014.

https://www.spacetelescope.org/images/potw

[nasa]

Look! A cosmic block party 🥳 In this Hubble image, you’ll find 50 spiral and dwarf galaxies hanging out in our cosmic neighborhood. The main focal point of stars is actually a dwarf galaxy. Dwarf galaxies often show a hazy structure, an ill-defined shape and an appearance somewhat akin to a swarm or cloud of stars — and UGC 685 is no exception to this. These data were gathered under Hubble’s Legacy ExtraGalactic UV Survey (LEGUS) program, the sharpest and most comprehensive ultraviolet survey of star-forming galaxies in the nearby universe. Image Credit: ESA/Hubble & NASA; the LEGUS team, B. Tully, D. Calzetti

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

[starwalkapp]

Hubble spots a swarm of stars ✨⠀ ⠀ This image from the NASA/ESA Hubble Space Telescope shows a dwarf galaxy named UGC 685. Such galaxies are small and contain just a tiny fraction of the number of stars in a galaxy like the Milky Way. Dwarf galaxies often show a hazy structure, an ill-defined shape, and an appearance somewhat akin to a swarm or cloud of stars—and UGC 685 is no exception to this. Classified as an SAm galaxy—a type of unbarred spiral galaxy—it is located about 15 million light-years from Earth.⠀ ⠀ These data were gathered under Hubble's LEGUS (Legacy ExtraGalactic UV Survey) program, the sharpest and most comprehensive ultraviolet survey of star-forming galaxies in the nearby universe.⠀ ⠀ LEGUS is imaging 50 spiral and dwarf galaxies in our cosmic neighborhood in multiple colors using Hubble's Wide Field Camera 3. The survey is picking apart the structures of these galaxies and resolving their constituent stars, clusters, groups and other stellar associations. Star formation plays a huge role in shaping its host galaxy. By exploring these targets in detail via both new observations and archival Hubble data, LEGUS will shed light on how stars form and cluster together, how these clusters evolve, how a star's formation affects its surroundings, and how stars explode at the end of their lives.⠀ ⠀ Provided by NASA's Goddard Space Flight Center⠀ Image Credit: ESA/Hubble & NASA; the LEGUS team, B. Tully, D. Calzetti; Acknowledgment: Judy Schmidt (Geckzilla) via Instagram https://ift.tt/2UKcAFA

[andromeda1023]

This image from the NASA/ESA Hubble Space Telescope shows a cosmic oddity, dwarf galaxy DDO 68.

This ragged collection of stars and gas clouds looks at first glance like a recently-formed galaxy in our own cosmic neighbourhood. But, is it really as young as it looks?

The dwarf galaxy DDO 68, also known as UGC 5340, lies about 40 million light-years away from Earth. (Constellation Leo)  Due to its proximity it became one of the 50 targets of LEGUS. (Legacy ExtraGalactic UV Survey)

In UGC 5340, a pocket of rapid star birth appears in the lower right corner. This region of star formation was probably triggered by a gravitational interaction with an unseen companion galaxy. But star formation is present across the entire body of UGC 5340, and the relatively young stars are responsible for the galaxy’s blue-white colour.

An image of this galaxy was already released back in 2014 (heic1421). This newly-processed image now also shows ultraviolet radiation Hubble captured from the galaxy.

Credit:  NASA, ESA;  Acknowledgement: A. Aloisi (Space Telescope Science Institute)

https://www.spacetelescope.org/images/heic1421a/

https://www.spacetelescope.org/images/heic1810d/

[spaceexp]

Hubble Spots a Swarm of Stars

NASA - Hubble Space Telescope patch. Sept. 8, 2019

This image from the NASA/ESA Hubble Space Telescope shows a dwarf galaxy named UGC 685. Such galaxies are small and contain just a tiny fraction of the number of stars in a galaxy like the Milky Way. Dwarf galaxies often show a hazy structure, an ill-defined shape, and an appearance somewhat akin to a swarm or cloud of stars — and UGC 685 is no exception to this. Classified as an SAm galaxy — a type of unbarred spiral galaxy — it is located about 15 million light-years from Earth. These data were gathered under Hubble’s LEGUS (Legacy ExtraGalactic UV Survey) program, the sharpest and most comprehensive ultraviolet survey of star-forming galaxies in the nearby universe. LEGUS is imaging 50 spiral and dwarf galaxies in our cosmic neighborhood in multiple colors using Hubble’s Wide Field Camera 3. The survey is picking apart the structures of these galaxies and resolving their constituent stars, clusters, groups and other stellar associations. Star formation plays a huge role in shaping its host galaxy. By exploring these targets in detail via both new observations and archival Hubble data, LEGUS will shed light on how stars form and cluster together, how these clusters evolve, how a star’s formation affects its surroundings, and how stars explode at the end of their lives.

Hubble Space Telescope (HST)

For more information about Hubble, visit: http://hubblesite.org/ http://www.nasa.gov/hubble http://www.spacetelescope.org/ Text Credits: ESA (European Space Agency)/NASA/Rob Garner/Image, Animation,  Credits: ESA/Hubble & NASA; the LEGUS team, B. Tully, D. Calzetti; Acknowledgment: Judy Schmidt (Geckzilla). Greetings, Orbiter.ch Full article

[startswithabang]

Hubble Catches New Stars, Individually, Forming In Galaxies Beyond The Milky Way

“There are a massive variety of star-forming regions nearby, and Hubble's new Legacy ExtraGalactic UV Survey (LEGUS) is now the sharpest, most comprehensive one ever.  By imaging 50 nearby, star-forming spiral and dwarf galaxies, astronomers can see how the galactic environment affects star-formation.”

Within galaxies, new stars are going to be formed from the existing population of gas. But how that gas collapses and forms stars, as well as the types, numbers, and locations of the stars that will arise, is highly dependent on the galactic environment into which they are born. Dwarf galaxies, for example, tend to form stars when a nearby gravitational interaction triggers them. These bursts occur periodically, leading to multiple populations of stars of different ages. Spirals, on the other hand, form their new stars mostly along the lines traced by their arms, where the dust and gas is densest. Thanks to the Hubble Space Telescope, we’re capable of finding these stars and resolving them individually, using a combination of optical and ultraviolet data.

The best part? These are individually resolved stars from well outside our own galaxy: in 50 independent ones. Here’s what Hubble’s new LEGUS survey is revealing.

[scifigeneration]

Astronomers release most complete ultraviolet-light survey of nearby galaxies

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. 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."

Image above:  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. Credits: NASA/ESA/LEGUS team

[martinnavarro]

Hubble y sus nuevas imágenes de galaxias cercanas

Hubble y sus nuevas imágenes de galaxias cercanas

Esta es la galaxia espiral NGC 3627, que está a 36 millones de años luz de distancia. NASA / ESA / LEGUS

El famoso telescopio espacial Hubble ha estado haciendo de las suyas y tomó algunas imágenes ultravioletas de galaxias cercanas y podemos decir casi como siempre que estas son impresionantes como mínimo.

Estas imágenes forman parte de un proyecto llamado Legacy ExtraGalactic UV Survey  o LEGUS…

[astroblogs]

De LEGUS-catalogus van het UV heelal, gemaakt met Hubble, is gepubliceerd

De LEGUS-catalogus van het UV heelal, gemaakt met Hubble, is gepubliceerd

Deze week is de Legacy ExtraGalactic UV Survey (LEGUS) verschenen, de catalogus van hoge-resolutie opnames van sterren en clusters van sterren in vijftig sterrenstelselsels gemaakt met de Hubble ruimtetelescoop in het ultraviolette gedeelte van het spectrum. Het gaat om sterrenstelsels binnen een straal van 60 miljoen lichtjaar afstand (da’s relatatief dichtbij), die met Hubble’s Wide Field…

[wigmund]

From SpaceTelescope.Org Picture of the Week; August 27, 2018:

GOODS-South Hubble Deep UV Legacy Field

Following on from last week’s Picture of the Week, this week we showcase the second part of the Hubble Deep UV (HDUV) Legacy Field, the GOODS-South view. With the addition of new ultraviolet light imagery, astronomers using the NASA/ESA Hubble Space Telescope have captured the largest panoramic view of the fire and fury of star birth in the distant Universe, encompassing 12 000 star-forming galaxies.

Hubble’s ultraviolet vision opens up a new window on the evolving Universe, tracking the birth of stars over the last 11 billion years up to the cosmos’s busiest star-forming period, which happened about three billion years after the Big Bang.

So far, ultraviolet light has been the missing piece of the cosmic puzzle. Now, combined with data in infrared, and visible light from Hubble and other space- and ground-based telescopes, astronomers have assembled the most comprehensive portrait yet of the Universe’s evolutionary history. The image straddles the gap between the very distant galaxies, which can only be viewed in infrared light, and closer galaxies, which can be seen across different wavelengths. The light from distant star-forming regions in remote galaxies started out as ultraviolet, but the expansion of the Universe has shifted the light into infrared wavelengths. By comparing images of star formation in the distant and nearby Universe, astronomers can get a better understanding of how nearby galaxies grew from small clumps of hot, young stars long ago.

The observation programme harnessed the ultraviolet vision of Hubble’s Wide Field Camera 3. This study extends and builds on the previous Hubble multi-wavelength data in the CANDELS-Deep (Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey) fields within the central part of the GOODS (The Great Observatories Origins Deep Survey) fields. This mosaic is 14 times the area of the Hubble Ultraviolet Ultra Deep Field released in 2014.

Links: Hubble contributes to painting a picture of the evolving Universe Credit: ESA/Hubble & NASA

[space--bot]

GOODS-South Hubble Deep UV Legacy Field

Following on from last week’s Picture of the Week, this week we showcase the second part of the Hubble Deep UV (HDUV) Legacy Field, the GOODS-South view. With the addition of new ultraviolet light imagery, astronomers using the NASA/ESA Hubble Space Telescope have captured the largest panoramic view of the fire and fury of star birth in the distant Universe, encompassing 12 000 star-forming galaxies.

Hubble’s ultraviolet vision opens up a new window on the evolving Universe, tracking the birth of stars over the last 11 billion years up to the cosmos’s busiest star-forming period, which happened about three billion years after the Big Bang.

So far, ultraviolet light has been the missing piece of the cosmic puzzle. Now, combined with data in infrared, and visible light from Hubble and other space- and ground-based telescopes, astronomers have assembled the most comprehensive portrait yet of the Universe’s evolutionary history. The image straddles the gap between the very distant galaxies, which can only be viewed in infrared light, and closer galaxies, which can be seen across different wavelengths. The light from distant star-forming regions in remote galaxies started out as ultraviolet, but the expansion of the Universe has shifted the light into infrared wavelengths. By comparing images of star formation in the distant and nearby Universe, astronomers can get a better understanding of how nearby galaxies grew from small clumps of hot, young stars long ago.

The observation programme harnessed the ultraviolet vision of Hubble’s Wide Field Camera 3. This study extends and builds on the previous Hubble multi-wavelength data in the CANDELS-Deep (Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey) fields within the central part of the GOODS (The Great Observatories Origins Deep Survey) fields. This mosaic is 14 times the area of the Hubble Ultraviolet Ultra Deep Field released in 2014.

Links

Hubble contributes to painting a picture of the evolving Universe

https://www.spacetelescope.org/images/potw

[astroimages]

A imagem acima mostra a galáxia anã, conhecida como UGC 685. Essas galáxias são pequenas e só possuem uma pequena fração das estrelas que galáxias como a Via Láctea possuem. Galáxias anãs mostram normalmente uma estrutura difusa, uma forma não muito bem definida e sua aparência lembra muito uma aglomeração, ou uma nuvem de estrelas, e a UGC 685 não é exceção. Classificada como uma galáxia do tipo SAm, ela é uma galáxia espiral sem barra, e está localizada a aproximadamente 15 milhões de anos-luz de distância da Terra. Essa imagem foi feita com dados obtidos pelo programa LEGUS do Telescópio Espacial Hubble. LEGUS significa, Legacy ExtraGalactic UV Survey, e tem como objetivo fazer a pesquisa mais nítida e mais compreensiva em ultravioleta de galáxias que formam estrelas no universo próximo. O LEGUS faz imagens de 50 galáxias espirais e anãs na nossa vizinhança cósmica em múltiplas cores, usando para isso a Wide Field Camera 3 do Hubble. A pesquisa está registrando as estruturas dessas galáxias e resolvendo suas estrelas, aglomerados, grupos, e outras associações estelares. A formação de estrelas tem um papel muito importante em moldar a forma da galáxia. Explorando essas galáxias em detalhe através de novas observações e dados de arquivos do Hubble, o LEGUS está lançando uma luz sobre como as estrelas se formam e como os aglomerados se mantêm unidos, como os aglomerados se desenvolvem e como a formação de estrelas afeta sua vizinhança, além de dar ideias sobre como as estrelas explodem no final de suas vidas. Crédito da imagem: ESA/Hubble & NASA; the LEGUS team, B. Tully, D. Calzetti Acknowledgement(s): Judy Schmidt (Geckzilla) Fonte: https://www.spacetelescope.org/images/potw1935a/

[tatmanblue]

Hubble Scopes Out a Galaxy of Stellar Birth by NASA Goddard Space Flight Center Via Flickr: This image displays a galaxy known as ESO 486-21 (with several other background galaxies and foreground stars visible in the field as well). ESO 486-21 is a spiral galaxy — albeit with a somewhat irregular and ill-defined structure — located some 30 million light-years from Earth. The NASA/ESA (European Space Agency) Hubble Space Telescope observed this object while performing a survey — the Legacy ExtraGalactic UV Survey (LEGUS) — of 50 nearby star-forming galaxies. The LEGUS sample was selected to cover a diverse range of galactic morphologies, star formation rates, galaxy masses and more. Astronomers use such data to understand how stars form and evolve within clusters, and how these processes affect both their home galaxy and the wider universe. ESO 486-21 is an ideal candidate for inclusion in such a survey because it is known to be in the process of forming new stars, which are created when large clouds of gas and dust (seen here in pink) within the galaxy crumple inwards upon themselves. Credit: NASA/ESA NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

[andromeda1023]

This image from the NASA/ESA Hubble Space Telescope shows a dwarf galaxy named UGC 685. Such galaxies are small and contain just a tiny fraction of the number of stars in a galaxy like the Milky Way. Dwarf galaxies often show a hazy structure, an ill-defined shape, and an appearance somewhat akin to a swarm or cloud of stars — and UGC 685 is no exception to this. Classified as an SAm galaxy — a type of unbarred spiral galaxy — it is located about 15 million light-years from Earth.

These data were gathered under Hubble’s LEGUS (Legacy ExtraGalactic UV Survey) program, the sharpest and most comprehensive ultraviolet survey of star-forming galaxies in the nearby universe.

LEGUS is imaging 50 spiral and dwarf galaxies in our cosmic neighborhood in multiple colors using Hubble’s Wide Field Camera 3. The survey is picking apart the structures of these galaxies and resolving their constituent stars, clusters, groups and other stellar associations. Star formation plays a huge role in shaping its host galaxy. By exploring these targets in detail via both new observations and archival Hubble data, LEGUS will shed light on how stars form and cluster together, how these clusters evolve, how a star’s formation affects its surroundings, and how stars explode at the end of their lives.

Text credit: ESA (European Space Agency) Image credit: ESA/Hubble & NASA; the LEGUS team, B. Tully, D. Calzetti; Acknowledgment: Judy Schmidt (Geckzilla)

https://www.nasa.gov/image-feature/goddard/2019/hubble-spots-a-swarm-of-stars