Appearances of the Refsdal supernova

This video shows the three appearances of the Refsdal supernova in the galaxy cluster MACS J1149.5+2223. Calculations showed that the first image of the supernova appeared in 1998 — an event not observed with a telescope. The second image produced an almost perfect Einstein Cross, which was observed in November 2014 (heic1505). The latest appearance was observed by the NASA/ESA Hubble Space telescope on 11 December 2015, as correctly predicted by seven different models.
The positions of all three events are highlighted in this video with animated supernovae, even though the Einstein Cross event is also visible in the original image.
http://www.spacetelescope.org/videos/heic1525a/

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Butterfly death throes

Butterfly_death_throes_node_full_image_2Many celestial objects are beautiful – swirling spiral galaxies or glittering clusters of stars are notable examples. But some of the most striking scenes are created during the death throes of intermediate-mass stars, when great clouds of superheated gas are expelled into space. These dying breaths form planetary nebulas like NGC 6302, captured here in this image from the NASA/ESA Hubble Space Telescope. Continue reading Butterfly death throes

M60-UCD1: An Ultra-Compact Dwarf Galaxy 
http://www.nasa.gov/mission_pages/chandra/multimedia/m60-dense-galaxy.html#.UkHNuNJ7JBk

NASA’s Hubble and Chandra Find Evidence for Densest Nearby Galaxy

M60-UCD1: An Ultra-Compact Dwarf Galaxy  http://www.nasa.gov/mission_pages/chandra/multimedia/m60-dense-galaxy.html#.UkHNuNJ7JBk

M60-UCD1: An Ultra-Compact Dwarf Galaxy
(www.nasa.gov)

Astronomers using NASA’s Hubble Space Telescope and Chandra X-ray Observatory and telescopes on the ground may have found the most crowded galaxy in our part of the universe.
The ultra-compact dwarf galaxy, known as M60-UCD1, is packed with an extraordinary number of stars and may be the densest galaxy near Earth. It is providing astronomers with clues to its intriguing past and its role in the galactic evolutionary chain.
M60-UCD1, estimated to be about 10 billion years old, is near the massive elliptical galaxy NGC 4649, also called M60, about 54 million light years from Earth. It is the most luminous known galaxy of its type and one of the most massive, weighing 200 million times more than our sun, based on observations with the W.M. Keck Observatory 10-meter telescope in Hawaii.
What makes M60-UCD1 so remarkable is that about half of this mass is found within a radius of only about 80 light years. The density of stars is about 15,000 times greater — meaning the stars are about 25 times closer to each other — than in Earth’s neighborhood in the Milky Way galaxy.
“Traveling from one star to another would be a lot easier in M60-UCD1 than it is in our galaxy, but it would still take hundreds of years using present technology,” said Jay Strader of Michigan State University in Lansing. Strader is the lead author of a paper about the research, which was published Sept. 20 in The Astrophysical Journal Letters.
The 6.5-meter Multiple Mirror Telescope in Arizona was used to study the amount of elements heavier than hydrogen and helium in stars in M60-UCD1. The values were found to be similar to our sun.
“The abundance of heavy elements in this galaxy makes it a fertile environment for planets and, potentially, for life to form,” said co-author Anil Seth of the University of Utah.
Another intriguing aspect of M60-UCD1 is the presence of a bright X-ray source in its center, revealed in Chandra data. One explanation for this source is a giant black hole weighing in at about 10 million times the mass of our sun.
Astronomers want to find out whether M60-UCD1 was born as a jam-packed star cluster or became more compact as stars were ripped away from it. Large black holes are not found in star clusters, so if the X-ray source is in fact due to a massive black hole, it was likely produced by collisions between M60-UCD1 and one or more nearby galaxies. M60-UCD1’s great mass and the abundances of elements heavier than hydrogen and helium are also arguments for the theory it is the remnant of a much larger galaxy.
“We think nearly all of the stars have been pulled away from the exterior of what once was a much bigger galaxy,” said co-author Duncan Forbes of Swinburne University in Australia. “This leaves behind just the very dense nucleus of the former galaxy, and an overly massive black hole.”
If this stripping did occur, then the galaxy originally was 50 to 200 times more massive than it is now, and the mass of its black hole relative to the original mass of the galaxy would be more like that of the Milky Way and many other galaxies. The stripping could have taken place long ago and M60-UCD1 may have been stalled at its current size for several billion years.
Read more at www.nasa.gov

hubble ii

Hubble Sees True Shapes of Galaxies 11 Billion Years Back in Time

hubble iiLooking 11 billion years back in time to when the universe was very young, astronomers have found that the anatomy of distant galaxies is not that different from galaxies seen in the nearby universe today. The results come from the Hubble Space Telescope Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). The largest project in the history of Hubble, it aims to explore galactic evolution in the early universe, and the very first seeds of cosmic structure at less than 1 billion years after the Big Bang.

Previous studies of this early epoch were inconclusive because they were limited to visible light. Because of the stretching of light by the expansion of the universe the visible light detected in distant galaxies actually maps only the ultraviolet emissions of the galaxies. Because this radiation only comes from regions of active star formation the galaxies appeared to be clumpy and messy, with no resemblance to the galaxy shapes we see around us today. By observing the galaxies in infrared light with Hubble’s Wide Field Camera 3, astronomers could observe how these distant galaxies would appear normally in visible light if their radiation were not stretched to infrared wavelengths by the expanding universe. For more information about this study, visit: http://www.spacetelescope.org/news/heic1315

Credit: ESA/Hubble & NASA. Acknowledgement: Luca Limatola

Hubble Tells a Tale of Galactic Collisions

Credit: ESA/Hubble & NASA. Acknowledgement: Luca Limatola

Credit: ESA/Hubble & NASA. Acknowledgement: Luca Limatola

When we look into the distant cosmos, the great majority of the objects we see are galaxies: immense gatherings of stars, planets, gas, dust, and dark matter, showing up in all kind of shapes. This Hubble picture registers several, but the galaxy catalogued as 2MASX J05210136-2521450 stands out at a glance due to its interesting shape.

This object is an ultraluminous infrared galaxy which emits a tremendous amount of light at infrared wavelengths. Scientists connect this to intense star formation activity, triggered by a collision between two interacting galaxies.

The merging process has left its signs: 2MASX J05210136-2521450 presents a single, bright nucleus and a spectacular outer structure that consists of a one-sided extension of the inner arms, with a tidal tail heading in the opposite direction, formed from material ripped out from the merging galaxies by gravitational forces.

The image is a combination of exposures taken by Hubble’s Advanced Camera for Surveys, using near-infrared and visible light.

European Space Agency/NASA Hubble

Read more at http://www.nasa.gov/mission_pages/hubble/main/index.html

This is an artist’s impression of a white dwarf (burned-out) star accreting rocky debris left behind by the star’s surviving planetary system. It was observed by Hubble in the Hyades star cluster. At lower right, an asteroid can be seen falling toward a Saturn-like disk of dust that is encircling the dead star. Infalling asteroids pollute the white dwarf’s atmosphere with silicon. Credit: NASA, ESA, and G. Bacon (STScI)

NASA’s Hubble Space Telescope Finds Dead Stars …

… ‘Polluted with Planet Debris

NASA’s Hubble Space Telescope has found the building blocks for Earth-sized planets in an unlikely place– the atmospheres of a pair of burned-out stars called white dwarfs.

These dead stars are located 150 light-years from Earth in a relatively young star cluster, Hyades, in the constellation Taurus. The star cluster is only 625 million years old. The white dwarfs are being polluted by asteroid-like debris falling onto them.

This is an artist’s impression of a white dwarf (burned-out) star accreting rocky debris left behind by the star’s surviving planetary system. It was observed by Hubble in the Hyades star cluster. At lower right, an asteroid can be seen falling toward a Saturn-like disk of dust that is encircling the dead star. Infalling asteroids pollute the white dwarf’s atmosphere with silicon. Credit: NASA, ESA, and G. Bacon (STScI)

This is an artist’s impression of a white dwarf (burned-out) star accreting rocky debris left behind by the star’s surviving planetary system. It was observed by Hubble in the Hyades star cluster. At lower right, an asteroid can be seen falling toward a Saturn-like disk of dust that is encircling the dead star. Infalling asteroids pollute the white dwarf’s atmosphere with silicon. Credit: NASA, ESA, and G. Bacon (STScI)

Hubble’s Cosmic Origins Spectrograph observed silicon and only low levels of carbon in the white dwarfs’ atmospheres. Silicon is a major ingredient of the rocky material that constitutes Earth and other solid planets in our solar system. Carbon, which helps determine properties and origin of planetary debris, generally is depleted or absent in rocky, Earth-like material.

“We have identified chemical evidence for the building blocks of rocky planets,” said Jay Farihi of the University of Cambridge in England. He is lead author of a new study appearing in the Monthly Notices of the Royal Astronomical Society. “When these stars were born, they built planets, and there’s a good chance they currently retain some of them. The material we are seeing is evidence of this. The debris is at least as rocky as the most primitive terrestrial bodies in our solar system.”

This discovery suggests rocky planet assembly is common around stars, and it offers insight into what will happen in our own solar system when our sun burns out 5 billion years from now.

Farihi’s research suggests asteroids less than 100 miles (160 kilometers) wide probably were torn apart by the white dwarfs’ strong gravitational forces. Asteroids are thought to consist of the same materials that form terrestrial planets, and seeing evidence of asteroids points to the possibility of Earth-sized planets in the same system.

The pulverized material may have been pulled into a ring around the stars and eventually funneled onto the dead stars. The silicon may have come from asteroids that were shredded by the white dwarfs’ gravity when they veered too close to the dead stars.

“It’s difficult to imagine another mechanism than gravity that causes material to get close enough to rain down onto the star,” Farihi said.

By the same token, when our sun burns out, the balance of gravitational forces between the sun and Jupiter will change, disrupting the main asteroid belt. Asteroids that veer too close to the sun will be broken up, and the debris could be pulled into a ring around the dead sun.

According to Farihi, using Hubble to analyze the atmospheres of white dwarfs is the best method for finding the signatures of solid planet chemistry and determining their composition.

“Normally, white dwarfs are like blank pieces of paper, containing only the light elements hydrogen and helium,”Farihi said. “Heavy elements like silicon and carbon sink to the core. The one thing the white dwarf pollution technique gives us that we just won’t get with any other planet-detection technique is the chemistry of solid planets.”

The two “polluted” Hyades white dwarfs are part of the team’s search of planetary debris around more than 100 white dwarfs, led by Boris Gansicke of the University of Warwick in England. Team member Detlev Koester of the University of Kiel in Germany is using sophisticated computer models of white dwarf atmospheres to determine the abundances of various elements that can be traced to planets in the Hubble spectrograph data.

Fahiri’s team plans to analyze more white dwarfs using the same technique to identify not only the rocks’ composition, but also their parent bodies.
Read more at http://www.nasa.gov/mission_pages/hubble/science/hyades-dwarf.html

The famous Hubble deep field of galaxies as seen here in the infrared at a wavelength of 3.6 microns. The new SEDS project that has observed this region has also studied many other deep extragalactic fields, covering a total area nearly six times that of the full moon. Credit: NASA/Spitzer and M. Ashby

The distant cosmos as seen in the infrared

The famous Hubble deep field of galaxies as seen here in the infrared at a wavelength of 3.6 microns. The new SEDS project that has observed this region has also studied many other deep extragalactic fields, covering a total area nearly six times that of the full moon. Credit: NASA/Spitzer and M. Ashby

The famous Hubble deep field of galaxies as seen here in the infrared at a wavelength of 3.6 microns. The new SEDS project that has observed this region has also studied many other deep extragalactic fields, covering a total area nearly six times that of the full moon. Credit: NASA/Spitzer and M. Ashby

At some stage after its birth in the big bang, the universe began to make galaxies. No one knows exactly when, or how, this occurred. For that matter, astronomers do not know how the lineages of our own Milky Way galaxy and its stars trace back to those first galaxies and their first stars, but astronomers have been working hard to find out. The Hubble Space Telescope announced in 1996 that it had stared at apparently dark sky for ten days at optical wavelengths, long enough to acquire a picture of the very distant universe. The resultant image, the Hubble Deep Field (HDF), reveals galaxies that are so far away that they existed when the universe was less than about 5% of its present age of 14 billion years. Since 1996 astronomers have been working to understand exactly what kinds of galaxies these remote objects are, and whether they bear any resemblance to our own Milky Way galaxy, either as it is now, or as it was when it was younger….
… Read more at: http://phys.org/news/2013-04-distant-cosmos-infrared.html#jCp