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From SpaceTelescope.Org Picture of the Week; October 15, 2018:

On The Hunt For Newborn Stars

This image, taken with the NASA/ESA Hubble Space Telescope's Wide Field Camera 3 (WFC3), shows a patch of space filled with galaxies of all shapes, colors, and sizes. WFC3 is able to view many such galaxies at an unprecedented resolution — high enough to locate and study regions of star formation in a bid to understand how new stars spring to life throughout the cosmos.

Stars are born within giant clouds of gas. These massive clouds, or stellar nurseries, grow unstable and begin to collapse under gravity, becoming the seeds that will grow into new stars. By analyzing the luminosity, size, and formation rate of different stellar nurseries, scientists hope to learn more about the processes that can lead to the formation of a newborn star. Studying nurseries within different galaxies will provide information about star formation at different points in time and space throughout the Universe.

Just below center in this image is a formation of galaxies akin to a smiling face! Two yellow-hued blobs hang atop a sweeping arc of light, forming a celestial object known as SDSSJ0952+3434. The lower, arc-shaped galaxy has the characteristic shape of a galaxy that has been gravitationally lensed — its light has passed near to a massive object en route to us, causing it to become distorted and stretched out of shape.

Credit: ESA/Hubble & NASA Acknowledgement: Judy Schmidt (geckzilla)

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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

[wigmund]

From SpaceTelescope.Org Picture of the Week; October 8, 2018:

Rings Upon Rings

This image from the NASA/ESA Hubble Space Telescope reveals a spiral galaxy named Messier 95 (also known as M95 or NGC 3351). Located about 35 million light-years away in the constellation of Leo (The Lion), this swirling spiral was discovered by astronomer Pierre Méchain in 1781, and cataloged by French astronomer Charles Messier just four days later. Messier was primarily a comet hunter, and was often left frustrated by objects in the sky that resembled comets but turned out not to be. To help other astronomers avoid confusing these objects in the future, he created his famous catalog of Messier objects.

Most definitely not a comet, Messier 95 is actually a barred spiral galaxy. The galaxy has a bar cutting through its center, surrounded by an inner ring currently forming new stars. Also our own Milky Way is a barred spiral.

As well as hosting this stellar nursery, Messier 95 is a known host of the dramatic and explosive final stages in the lives of massive stars: supernovae. In March 2016 a spectacular supernova named SN 2012aw was observed in the outer regions of one of Messier 95’s spiral arms. Once the light from the supernova had faded, astronomers were able to compare observations of the region before and after the explosion to find out which star had “disappeared” — the progenitor star. In this case, the star was an especially huge red supergiant up to 26 times more massive than the Sun.

Credit: ESA/Hubble & NASA

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From SpaceTelescope.Org Picture of the Week; August 9, 2010:

Frenzied Star Birth In Haro 11

Haro 11 appears to shine gently amid clouds of gas and dust, but this placid facade belies the monumental rate of star formation occurring in this “starburst” galaxy. By combining data from the NASA/ESA Hubble Space Telescope and ESO’s Very Large Telescope, astronomers have created a new image of this incredibly bright and distant galaxy. The team of astronomers from Stockholm University, Sweden, and the Geneva Observatory, Switzerland, have identified 200 separate clusters of very young, massive stars. Most of these are less than 10 million years old. Many of the clusters are so bright in infrared light that astronomers suspect that the stars are still emerging from the cloudy cocoons where they were born. The observations have led the astronomers to conclude that Haro 11 is most likely the result of a merger between a galaxy rich in stars and a younger, gas-rich galaxy. Haro 11 is found to produce stars at a frantic rate, converting about 20 solar masses of gas into stars every year.

Haro galaxies, first discovered by the noted astronomer Guillermo Haro in 1956, are defined by unusually intense blue and violet light. Usually this high energy radiation comes from the presence of many newborn stars or an active galactic nucleus. Haro 11 is about 300 million light-years away and is the second closest of such starburst galaxies.

The paper describing this result (“Super star clusters in Haro 11: Properties of a very young starburst and evidence for a near-infrared flux excess”, by A. Adamo et al.) is available athttp://adsabs.harvard.edu/doi/10.1111/j.1365-2966.2010.16983.x

Credit: ESA/Hubble/ESO and NASA

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From SpaceTelescope.Org Picture of the Week; June 4, 2018:

Threads of Blue

A ripple of bright blue threads through this galaxy like a misshapen lake system. The foreground of this image is littered with nearby stars with their gleaming diffraction spikes. A keen eye can also spot a few other galaxies that, while masquerading as stars at first glance, reveal their true nature on closer inspection.

The central galaxy streaked with color, IC 4870, was discovered by DeLisle Stewart in 1900 and is located approximately 28 million light-years away. It contains an active galactic nucleus, or AGN: an extremely luminous central region so alight with radiation that it can outshine the rest of the galaxy put together. AGNs emit radiation across the complete electromagnetic spectrum, from radio waves to gamma-rays, produced by the action of a central supermassive black hole that is devouring material getting too close to it. IC 4870 is also a Seyfert galaxy, a particular kind of AGN with characteristic emission lines.

IC 4870 has been imaged by Hubble for several studies of nearby active galaxies. By using Hubble to explore the small-scale structures of AGN in nearby galaxies, astronomers can observe the traces of collisions and mergers, central galactic bars, nuclear starbursts, jets or outflows, and other interactions between a galactic nucleus and its surrounding environment. Images such as this can help astronomers understand more about the true nature of the galaxies we see throughout the cosmos.

Credit: ESA/Hubble & NASA

[wigmund]

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

An Extraordinary Celestial Spiral

This remarkable picture from the Advanced Camera for Surveys on the NASA/ESA Hubble Space Telescope shows one of the most perfect geometrical forms created in space. It captures the formation of an unusual pre-planetary nebula, known as IRAS 23166+1655, around the star LL Pegasi (also known as AFGL 3068) in the constellation of Pegasus (the Winged Horse).

The striking picture shows what appears to be a thin spiral pattern of astonishingly regularity winding around the star, which is itself hidden behind thick dust. The spiral pattern suggests a regular periodic origin for the nebula’s shape. The material forming the spiral is moving outwards a speed of about 50 000 km/hour and, by combining this speed with the distance between layers, astronomers calculate that the shells are each separated by about 800 years.

The spiral is thought to arise because LL Pegasi is a binary system, with the star that is losing material and a companion star orbiting each other. The spacing between layers in the spiral is expected to directly reflect the orbital period of the binary, which is indeed estimated to be also about 800 years.

The creation and shaping of planetary nebulae is an exciting area of stellar evolution. Stars with masses from about half that of the Sun up to about eight times that of the Sun do not explode as supernovae at the ends of their lives. Instead a more regal end awaits them as their outer layers of gas are shed and drift into space, creating striking and intricate structures that to Earth-bound observers often look like dramatic watercolor paintings. IRAS 23166+1655 is just starting this process and the central star has yet to emerge from the cocoon of enveloping dust.

This picture was created from images from the Wide Field Channel of the Advanced Camera for Surveys on Hubble. Images through a yellow filter (F606W, colored blue) were combined with images through a near-infra red filter (F804W, colored red). The exposure times were 11 minutes and 22 minutes respectively and the field of view spans about 80 arcseconds.

Links: Paper discussing the intriguing AFGL 3068 (PDF format) Credit: ESA/NASA & R. Sahai

[wigmund]

From SpaceTelescope.Org Picture of the Week; June 14, 2010:

A Lucky Observation Of An Enigmatic Cloud

The little-known nebula IRAS 05437+2502 billows out among the bright stars and dark dust clouds that surround it in this striking image from the Hubble Space Telescope. It is located in the constellation of Taurus (the Bull), close to the central plane of our Milky Way galaxy. Unlike many of Hubble’s targets, this object has not been studied in detail and its exact nature is unclear. At first glance it appears to be a small, rather isolated, region of star formation and one might assume that the effects of fierce ultraviolet radiation from bright young stars probably were the cause of the eye-catching shapes of the gas. However, the bright boomerang-shaped feature may tell a more dramatic tale. The interaction of a high velocity young star and the cloud of gas and dust may have created this unusually sharp-edged bright arc. Such a reckless star would have been ejected from the distant young cluster where it was born and would travel at 200 000 km/hour or more through the nebula.

This faint cloud was originally discovered in 1983 by the Infrared Astronomical Satellite (IRAS), the first space telescope to survey the whole sky in the infrared. IRAS was run by the United States, the Netherlands, and the United Kingdom and found huge numbers of new objects that were invisible from the ground.

This image was taken with the Wide Field Channel of the Advanced Camera for Surveys on Hubble. It was part of a “snapshot” survey. These are lists of observations that are fitted into Hubble’s busy schedule when possible, without any guarantee that the observation will take place — so it was fortunate that the observation was made at all! This picture was created from images taken through yellow (F606W) and near-infrared (F814W) filters. The exposure times were about eleven minutes per filter and the field of view is about 100 arcseconds across.

Links

Sahai, R., Claussen, M., Morris, M., & Ainsworth, R. 2009, Bulletin of the American Astronomical Society, 41, 456

[Rosen, A., Sahai, R., Claussen, M., & Morris, M. 2010, Bulletin of the American Astronomical Society, 41, 264

Credit: ESA/Hubble, R. Sahai and NASA

[wigmund]

From SpaceTelescope.Org Picture of the Week; December 20, 2010:

Barred Spiral Bares All

The galaxy captured in this image, called UGC 12158, certainly isn’t camera-shy: this spiral stunner is posing face-on to the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys, revealing its structure in fine detail.

UGC 12158 is an excellent example of a barred spiral galaxy in the Hubble sequence — a scheme used to categorise galaxies based on their shapes. Barred spirals, as the name suggest, feature spectacular swirling arms of stars that emanate from a bar-shaped centre. Such bar structures are common, being found in about two thirds of spiral galaxies, and are thought to act as funnels, guiding gas to their galactic centres where it accumulates to form newborn stars. These aren’t permanent structures: astronomers think that they slowly disperse over time, so that the galaxies eventually evolve into regular spirals.

The appearance of a galaxy changes little over millions of years, but this image also contains a short-lived and brilliant interloper — the bright blue star just to the lower left of the centre of the galaxy is very different from the several foreground stars seen in the image. It is in fact a supernova inside UGC 12158 and much further away than the Milky Way stars in the field — at a distance of about 400 million light-years! This stellar explosion, called SN 2004ef, was first spotted by two British amateur astronomers in September 2004 and the Hubble data shown here form part of the follow-up observations.

This picture was created from images taken with the Wide Field Channel of Hubble’s Advanced Camera for Surveys. Images through blue (F475W, coloured blue), yellow (F606W, coloured green) and red (F814W, coloured red) as well as a filter that isolates the light from glowing hydrogen (F658W, also coloured red) have been included. The exposure times were 1160 s, 700 s, 700 s and 1200 s respectively. The field of view is about 2.3 arcminutes across.

Credit: ESA/Hubble & NASA