ASTRONOMY: A New View of an Icon

Hi My Friends: AL VUELO DE UN QUINDE EL BLOG., The Eagle Nebula as never seen before. In 1995, the Hubble Space Telescope's 'Pillars of Creation' image of the Eagle Nebula became one of the most iconic images of the 20th century. Now, two of ESA's orbiting observatories have shed new light on this enigmatic star-forming region.

Combining almost opposite ends of the electromagnetic spectrum, this composite of the Herschel in far-infrared and XMM-Newton’s X-ray images shows how the hot young stars detected by the X-ray observations are sculpting and interacting with the surrounding ultra-cool gas and dust, which, at only a few degrees above absolute zero, is the critical material for star formation itself. Both wavelengths would be blocked by Earth’s atmosphere, so are critical to our understanding of the lifecycle of stars

Credits: far-infrared: ESA/Herschel/PACS/SPIRE/Hill, Motte, HOBYS Key Programme Consortium; X-ray: ESA/XMM-Newton/EPIC/XMM-Newton-SOC/Boulanger

This 1995 Hubble Space Telescope image of the ‘Pillars of Creation’ is probably the most famous astronomical image of the 20th Century. Taken in visible light using a combination of SII/H-alpha and OIII filters, it shows a part of the Eagle Nebula where new stars are forming. The tallest pillar is around 4 light-years high

Credits: NASA/ESA/STScI, Hester & Scowen (Arizona State University)

XMM-Newton’s images of the Eagle Nebula region in X-rays, which here is colour-coded to show different energy levels (red: 0.3–1 keV, green: 1–2 keV and blue: 2–8 keV) is helping astronomers to investigate a theory that the Eagle Nebula is being powered by a hidden supernova remnant. The researchers are looking for signs of very diffuse emission and how far this extends around the region. They believe that an absence of this X-ray emission beyond that found by previous orbiting space telescopes (Chandra and Spitzer) would support the supernova remnant theory. The work on this is continuing

Credits: ESA/XMM-Newton/EPIC/XMM-Newton-SOC/Boulanger

Messier 16 is a diffuse emission nebula that contains the young open cluster NGC6611. The iconic ‘Pillars of Creation’ image taken with the Hubble Space Telescope in 1995 is captured in near-infrared by the VLT, which penetrates straight through the obscuring gas and dust, rendering them almost invisible. The pillars are only a small portion of the extensive nebulous region imaged in far-infrared by ESA’s Herschel Space Observatory, which shows cool dust and gas tendrils being carved away by the hot stars seen in the X-ray image from XMM-Newton. The wide-field optical image from the ESO MPG telescope puts the pillars into context against the full scale of the nebula, which is over 75 light-years across

Credits: far-infrared: ESA/Herschel/PACS/SPIRE/Hill, Motte, HOBYS Key Programme Consortium; ESA/XMM-Newton/EPIC/XMM-Newton-SOC/Boulanger; optical: MPG/ESO;near-infrared/VLT/ISAAC/McCaughrean & Andersen/AIP/ESO

The 8.2m-diameter VLT’s ANTU telescope imaged the famous Pillars of Creation region and its surroundings in near-infrared using the ISAAC instrument. This enabled astronomers to penetrate the obscuring dust in their search to detect newly formed stars. The research into the ‘evaporating gaseous globules’ (EGGs), which were first detected in the Hubble images, needed the near-infrared capabilities and resolution of the VLT to peel back the layers of dust and detect the low-mass young stars cocooned within the EGG shells. The near-infrared results showed that 11 of the 73 EGGs detected possibly contained stars, and that the tips of the pillars contain stars and nebulosity not seen in the Hubble image

Credits: VLT/ISAAC/McCaughrean & Andersen/AIP/ESO

This Herschel image of the Eagle Nebula, colour coded to 70 microns for blue and 160 microns for green using the PACS (Photodetector Array Camera) and 250 microns for red using the SPIRE (Spectral and Photometric Imaging Receiver) shows the self-emission of the intensely cold nebula’s gas and dust as never seen before. Each colour shows a different temperature of dust, from around 10 degrees above absolute zero (10K) for the red, up to around 40K for the blue. In the far–infrared, the nebula shows its intricate tendril nature, with vast cavities forming an almost cave-like surrounding to the famous pillars, which take on an ethereal ghostly appearance. The gas and dust provide the material for the star formation that is still under way inside this enigmatic nebula

Credits: ESA/Herschel/PACS/SPIRE/Hill, Motte, HOBYS Key Programme Consortium

Up to 1998 the ESA ISO (Infrared Space Observatory) was the most sensitive mid infrared telescope ever built. ISO observations were performed at 7 microns (and 15 microns, not shown) aiming to detect embedded sources in the pillars

Credits: ESA/ISO/Pilbratt et al.
The Eagle Nebula as never seen before. In 1995, the Hubble Space Telescope's 'Pillars of Creation' image of the Eagle Nebula became one of the most iconic images of the 20th century. Now, two of ESA's orbiting observatories have shed new light on this enigmatic star-forming region. The Eagle Nebula is 6500 light-years away in the constellation of Serpens. It contains a young hot star cluster, NGC6611, visible with modest back-garden telescopes, that is sculpting and illuminating the surrounding gas and dust, resulting in a huge hollowed-out cavity and pillars, each several light-years long.
The Hubble image hinted at new stars being born within the pillars, deeply inside small clumps known as 'evaporating gaseous globules' or EGGs. Owing to obscuring dust, Hubble's visible light picture was unable to see inside and prove that young stars were indeed forming.
The ESA Herschel Space Observatory's new image shows the pillars and the wide field of gas and dust around them. Captured in far-infrared wavelengths, the image allows astronomers to see inside the pillars and structures in the region.
In parallel, a new multi-energy X-ray image from ESA's XMM-Newton telescope shows those hot young stars responsible for carving the pillars.
Combining the new space data with near-infrared images from the European Southern Observatory's (ESO's) Very Large Telescope at Paranal, Chile, and visible-light data from its Max Planck Gesellschaft 2.2m diameter telescope at La Silla, Chile, we see this iconic region of the sky in a uniquely beautiful and revealing way.
In far-infrared, Herschel detects this cold dust and the pillars reappear, this time glowing in their own light.
Intricate tendrils of dust and gas are seen to shine, giving astronomers clues about how it interacts with strong ultraviolet light from the hot stars seen by XMM-Newton.
In 2001, Very Large Telescope near-infrared images had shown only a small minority of the EGGs were likely to contain stars being born.
However, Herschel's image makes it possible to search for young stars over a much wider region and thus come to a much fuller understanding of the creative and destructive forces inside the Eagle Nebula.
Earlier mid-infrared images from ESA's Infrared Space Observatory and NASA's Spitzer, and the new XMM-Newton data, have led astronomers to suspect that one of the massive, hot stars in NGC6611 may have exploded in a supernova 6000 years ago, emitting a shockwave that destroyed the pillars.
However, because of the distance of the Eagle Nebula, we won't see this happen for several hundred years yet.
Powerful ground-based telescopes continue to provide astonishing views of our Universe, but images in far-infrared, mid-infrared and X-ray wavelengths are impossible to obtain owing to the absorbing effects of Earth's atmosphere.
Space-based observatories such as ESA's Herschel and XMM-Newton help to peel back that veil and see the full beauty of the Universe across the electromagnetic spectrum.
With regions like the Eagle Nebula, combining all of these observations helps astronomers to understand the complex yet amazing lifecycle of stars. ESA.
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com

Science: Biologists Replicate Key Evolutionary Step in Life on Earth

Hi My Friends: AL VUELO DE UN QUINDE EL BLOG., More than 500 million years ago, single-celled organisms on Earth's surface began forming multi-cellular clusters that ultimately became plants and animals.

Green cells are undergoing cell death, a cellular division-of-labor--fostering new life.

Credit: Will Ratcliff and Mike Travisano

Multi-cellular 'snowflake' yeast images with a blue cell-wall stain and red dead-cell stain.

Credit: Will Ratcliff and Mike Travisano
First steps in the transition to multi-cellularity: 'snowflake' yeast with dead cells stained red.

Credit: Will Ratcliff and Mike Travisano

A multi-cellular yeast consisting of hundreds of cells.

Credit: Will Ratcliff and Mike Travisano Multi-cellular yeast individuals containing central dead cells, which promote reproduction.

Credit: Will Ratcliff and Mike Travisano Aberrant shapes of multi-cellular yeast's dead cells: break points for reproduction.

Credit: Will Ratcliff and Mike Travisano

More than 500 million years ago, single-celled organisms on Earth's surface began forming multi-cellular clusters that ultimately became plants and animals.
Just how that happened is a question that has eluded evolutionary biologists.
Now scientists have replicated that key step in the laboratory using common Brewer's yeast, a single-celled organism.
The yeast "evolved" into multi-cellular clusters that work together cooperatively, reproduce and adapt to their environment--in essence, they became precursors to life on Earth as it is today.
The results are published in this week's issue of the journal Proceedings of the National Academy of Sciences (PNAS).
"The finding that the division-of-labor evolves so quickly and repeatedly in these 'snowflake' clusters is a big surprise," says George Gilchrist, acting deputy division director of the National Science Foundation's (NSF) Division of Environmental Biology, which funded the research.
"The first step toward multi-cellular complexity seems to be less of an evolutionary hurdle than theory would suggest," says Gilchrist. "This will stimulate a lot of important research questions."
It all started two years ago with a casual comment over coffee that bridging the famous multi-cellularity gap would be "just about the coolest thing we could do," recalled Will Ratcliff and Michael Travisano, scientists at the University of Minnesota (UMN) and authors of the PNAS paper.
Other authors of the paper are Ford Denison and Mark Borrello of UMN.
Then came the big surprise: it wasn't that difficult.
Using yeast cells, culture media and a centrifuge, it only took the biologists one experiment conducted over about 60 days.
"I don't think anyone had ever tried it before," says Ratcliff. "There aren't many scientists doing experimental evolution, and they're trying to answer questions about evolution, not recreate it."
The results have earned praise from evolutionary biologists around the world.
"To understand why the world is full of plants and animals, including humans, we need to know how one-celled organisms made the switch to living as a group, as multi-celled organisms," says Sam Scheiner, program director in NSF's Division of Environmental Biology.
"This study is the first to experimentally observe that transition," says Scheiner, "providing a look at an event that took place hundreds of millions of years ago."
In essence, here's how the experiments worked:
The scientists chose Brewer's yeast, or Saccharomyces cerevisiae, a species of yeast used since ancient times to make bread and beer because it is abundant in nature and grows easily.
They added it to nutrient-rich culture media and allowed the cells to grow for a day in test tubes.
Then they used a centrifuge to stratify the contents by weight.
As the mixture settled, cell clusters landed on the bottom of the tubes faster because they are heavier. The biologists removed the clusters, transferred them to fresh media, and agitated them again.
Sixty cycles later, the clusters--now hundreds of cells--looked like spherical snowflakes.
Analysis showed that the clusters were not just groups of random cells that adhered to each other, but related cells that remained attached following cell division.
That was significant because it meant that they were genetically similar, which promotes cooperation. When the clusters reached a critical size, some cells died off in a process known as apoptosis to allow offspring to separate.
The offspring reproduced only after they attained the size of their parents.
"A cluster alone isn't multi-cellular," Ratcliff says. "But when cells in a cluster cooperate, make sacrifices for the common good, and adapt to change, that's an evolutionary transition to multi-cellularity."
In order for multi-cellular organisms to form, most cells need to sacrifice their ability to reproduce, an altruistic action that favors the whole but not the individual, Ratcliff says.
For example, all cells in the human body are essentially a support system that allows sperm and eggs to pass DNA along to the next generation.
Thus multi-cellularity is by its nature very cooperative.
"Some of the best competitors in nature are those that engage in cooperation, and our experiment bears that out," says Travisano.
Evolutionary biologists have estimated that multi-cellularity evolved independently in about 25 groups.
Travisano and Ratcliff wonder why it didn't evolve more often since it's not that difficult to recreate in a lab.
Considering that trillions of one-celled organisms lived on Earth for millions of years, it seems like it should have, Ratcliff says.
That may be a question the biologists will answer in the future using the fossil record for thousands of generations of multi-cellular clusters, which are stored in a freezer in Travisano's lab.
Since the frozen samples contain multiple cell lines that independently became multi-cellular, the researchers can compare them to learn whether similar or different mechanisms and genes were responsible in each case, Travisano says.
The next steps will be to look at the role of multi-cellularity in cancer, aging and other critical areas of biology.
"Multi-cellular yeast is a valuable resource for investigating a wide variety of medically and biologically important topics," Travisano says.
"Cancer was recently described as a fossil from the origin of multi-cellularity, which can be directly investigated with the yeast system.
"Similarly the origins of aging, development and the evolution of complex morphologies are open to direct experimental investigation that would otherwise be difficult or impossible."
-NSF-
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com

ASTRONOMÍA: Las Magníficas Antenas de ALMA

Hola amigos: AL VUELO DE UN QUINDE EL BLOG., Los trabajadores del proyecto Gran Conjunto Milimétrico-submilimétrico de Atacama (ALMA) están parados al lado de tres de las antenas del telescopio. Esta fotografía da la real dimensión de la escala de las antenas gigantes, cuyos diámetros de 12 metros son unas siete veces la altura humana promedio. Cuando esté terminado, ALMA consistirá de 66 antenas de alta precisión, 54 de las cuales con antenas parabólicas de 12 metros, como se aprecia en esta imagen, y 12 más compactas con diámetros de 7 metros. El vehículo de transporte amarillo de 28 ruedas, que debe ser suficientemente potente para cargar las antenas de 100 toneladas, está construído en una similar escala gigantesca. Esta fotografía fue tomada en el Centro de Apoyo a las Operaciones ALMA en las laderas de los Andes chilenos a 2900 metros de altitud, donde se montan y se prueban las antenas. A la izquierda está una de las antenas europeas de ALMA, apuntando hacia el horizonte. Detrás de ella está una de las antenas proporcionada al proyecto por Japón, mientras que a la derecha, en el vehículo de transporte y apuntando hacia arriba, hay otra antena europea.

Esta es la primera antena europea que inicia su viaje hacia el Lugar de Operaciones del Conjunto en el Llano de Chajnantor, fotografiada en Julio de 2011 (ver eso1127).

Desde que esta fotografía fue tomada, las antenas y otras como ellas, han sido puestas en operación en Chajnantor a medida que ALMA ha hecho sus primeras observaciones científicas (ver eso1137).

ALMA está diseñado para estudiar el Universo frío – el vestigio de radiación del Big Bang y el gas molecular y el polvo a partir de los cuales se originan las estrellas, planetas y galaxias.

ALMA, una instalación astronómica internacional, es una sociedad de Europa, América del Norte y Asia del Este en cooperación con la República de Chile.

La construcción y las operaciones de ALMA son dirigidas por ESO en representación de Europa, por el National Radio Astronomy Observatory (NRAO) en representación de América del Norte, y por el National Astronomical Observatory de Japón (NAOJ) en representación de Asia del Este.

El Observatorio Conjunto ALMA (JAO) proporciona la conducción unificada y la administración de la construcción, comisionado y operación de ALMA.La distorsión es débil y, por lo tanto, casi imperceptible al ojo humano. Sin embargo, debido a que rastrear el cielo con 17 filtros permite mediciones de distancia extremadamente precisas, es posible determinar si dos galaxias que parecen estar cerca entre si en realidad están a distancias muy diferentes de la Tierra.

Después de identificar los sistemas de lentes galácticos, la distorsión puede ser medida promediando entre miles de galaxias. Con más de 4000 lentes galácticos identificados, esta medición COMBO-17 es un método ideal para ayudar a los astrónomos a comprender mejor la materia oscura.

Veinticinco antenas ALMA europeas están siendo proporcionadas por ESO a través de un contrato con el Consorcio europeo AEM. ALMA también tendrá 25 antenas proporcionadas por América del Norte, y 16 por Asia del Este.

Crédito:ESO/S. Stanghellini

Guillermo Gonzalo Sánchez Achutegui

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ASTRONOMÍA: Kepler Descubre el Sistema Solar Más Pequeño

Hola amigos: AL VUELO DE UN QUINDE EL BLOG:Un equipo de astrónomos utilizando el Telescopio Espacial Kepler de la NASA han descubierto el sistema planetario más pequeño detectado hasta ahora, formado por tres planetas rocosos que giran alrededor de su estrella, llamada KOI-961. una enana roja con un diámetro seis veces más pequeño que el del Sol. Los planetas tienen un radio de 0,78, 0,73 y 0,57 veces el de nuestro planeta y el más pequeño de los tres tiene un tamaño parecido al de Marte.Los tres parecen ser rocosos, como la Tierra, aunque orbitan muy cerca de su estrella, con lo que la temperatura es demasiado caliente como para que pueda existir agua líquida, uno de los elementos fundamentales para la vida. De los más de 700 planetas confirmados que orbitan otras estrellas, denominados exoplanetas, sólo unos cuantos son rocosos. Sin embargo, la NASA destaca que puesto que las enanas rojas son el tipo más común de estrella en la Vía Láctea, este descubrimiento apunta a que, pese a que sean menos comunes, la galaxia podría estar llena de planetas rocosos similares.

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Mini Planetary System
This artist's concept depicts an itsy bitsy planetary system -- so compact, in fact, that it's more like Jupiter and its moons than a star and its planets.

Astronomers using data from NASA's Kepler mission and ground-based telescopes recently confirmed that the system, called KOI-961, hosts the three smallest exoplanets known so far to orbit a star other than our sun.

An exoplanet is a planet that resides outside of our solar system. The star, which is located about 130 light-years away in the Cygnus constellation, is what's called a red dwarf. It's one-sixth the size of the sun, or just 70 percent bigger than Jupiter.

The star is also cooler than our sun, and gives off more red light than yellow.The smallest of the three planets, called KOI-961.03, is actually located the farthest from the star, and is pictured in the foreground.

This planet is about the same size as Mars, with a radius only 0.57 times that of Earth. The next planet to the upper right is KOI-961.01, which is 0.78 times the radius of Earth. The planet closest to the star is KOI-961.02, with a radius 0.73 times the Earth's.

All three planets whip around the star in less than two days, with the closest planet taking less than half a day. Their close proximity to the star also means they are scorching hot, with temperatures ranging from 350 to 836 degrees Fahrenheit (176 to 447 degrees Celsius).

The star's habitable zone, or the region where liquid water could exist, is located far beyond the planets.The ground-based observations contributing to these discoveries were made with the Palomar Observatory, near San Diego, Calif., and the W.M. Keck Observatory atop Mauna Kea in Hawaii.

Image credit: NASA/JPL-Caltech
Pero estos planetas son los primeras rocosos que se encuentran orbitando alrededor de un tipo de estrella oscura y pequeña, una enana roja, el tipo más común de la Vía Láctea. Su existencia sugiere que la galaxia podría estar llena de planetas rocosos similares y hay una buena probabilidad de que muchos están en la zona habitable.

Kepler vigila más de 150.000 estrellas en busca de planetas o candidatos a planetas y que detecta por el descenso en el brillo de los astros causado por el cruce o tránsito de planetas. El principal investigador de la misión Kepler en el Instituto de Ciencias Exoplanetarias de la NASA en Pasadena (California), John Johnson, confirmó que es "el sistema solar más pequeño encontrado hasta ahora".

Johnson señaló que este sistema se parece más a Júpiter y sus lunas que a cualquier otro descubierto hasta ahora, lo que demuestra "la diversidad de sistemas planetarios en nuestra Galaxia". NASA
Guillermo Gonzalo Sánchez Achutegui

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ENERGÍA: Gaviotas, murciélagos y escarabajos impactan en los parques eólicos

Hola amigos: AL VUELO DE UN QUINDE EL BLOG., Los parques eólicos afectan en Castilla y León no solo a aves como el buitre, sino que incluso colisionan alguna gaviota, murciélagos y hasta el ciervo volante, un escarabajo de gran tamaño, según datos de la Sociedad Española de Ornitología (SEO)/BirdLife recogidos hoy por EFE.

Colonia de gaviotas
Hay ejemplares de gaviota que se reproducen con más facilidad que otrosCada miembro de la población es distinto del resto. Por eso algunos tienen más éxito en la reproducción que otros.Kalipedia.

SUIZA- ANIMALES:ZUR124 ZÚRICH (SUIZA) 18/8/2010.- Dos murciélagos frugívoros de Livingstone cuelgan de un árbol en el zoológico de Zuercher en Zúrich, Suiza, hoy, miércoles 18 de agosto de 2010. Los murciélagos de la fruta o frugívoros, debido a su dieta a base de frutas, son conocidos también como zorros voladores por su morro parecido al de estos animales. EFE/WALTER

Por su parte, la Asociación de Promotores de Energía Eólica de Castilla y León (APECYL) ha cuestionado el rigor de estos datos y ha recordado que todos los parques cumplen una exigente normativa de respecto al medio ambiente.
Un reciente informe de la entidad conservacionista SEO ha alertado de que los parques eólicos causan anualmente la muerte en España de entre 6 y 18 millones de aves y murciélagos, entre ellos los cerca de doscientos parques instalados en Castilla y León.
Este análisis destaca los casos de Burgos y de Soria, donde garcetas, ratoneros, cernícalos, milanos, grullas, alondras, mirlos y sobre todo buitres impactan contra aerogeneradores.
Incluso perdices, jilgueros, cuervos, gorriones y hasta laguna gaviota, además de murciélagos, encuentran un obstáculo en estas instalaciones de energía limpia.
No obstante, la tasa de mortalidad es solo del 0,3 por ciento en casos como el del buitre leonado en Soria, según los datos oficiales de los últimos años, aunque SEO estima que la incidencia es mayor de la que reflejan esas cifras.
Fuentes de la organización conservacionista han explicado a EFE que el mayor problema es la elección de los lugares en que se instalan los parques eólicos, debido a una evaluación de impacto ambiental que en ocasiones no tiene en cuenta las zonas sensibles para las aves.
Por su parte, el secretario general de la Asociación de Promotores de Energía Eólica de Castilla y León (APECYL), Eugenio García, en declaraciones a EFE, ha lamentado la "falta de rigor" de unos datos que se mueven en una horquilla "de 6 a 18 millones, con un margen de 12 millones" de aves y murciélagos afectados.
El representante de la Asociación ha recordado que antes de instalar cualquier parque eólico se llevan a cabo numerosos estudios para minimizar su impacto y para que éste sea "asumible", ya en caso contrario la Administración no los autoriza, puesto que ejerce un control "muy riguroso".
Eugenio García ha destacado que la mortalidad de aves en las carreteras o incluso capturadas por gatos es "infinitamente mayor" que en parques eólicos, como demuestran numerosos estudios científicos. EFE
Guillermo Gonzalo Sánchez Achutegui

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ayabaca@hotmail.com

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Astronomy: Hubble Pinpoints Farthest Protocluster of Galaxies Ever Seen

Hi My Friends: AL VUELO DE UN QUINDE EL BLOG., Using NASA's Hubble Space Telescope, astronomers have uncovered a cluster of galaxies in the initial stages of development. It is the most distant such grouping ever observed in the early universe. › Larger image

The composite image taken in visible and near-infrared light, reveals the location of five tiny galaxies clustered together 13.1 billion light-years away. The circles pinpoint the galaxies. Credit: NASA, ESA, M. Trenti (University of Colorado, Boulder and Institute of Astronomy, University of Cambridge, U.K.), L. Bradley (Space Telescope Science Institute, Baltimore), and the BoRG team.

In a random sky survey made in near-infrared light, Hubble found five tiny galaxies clustered together 13.1 billion light-years away. They are among the brightest galaxies at that epoch and very young -- existing just 600 million years after the big bang.

Galaxy clusters are the largest structures in the universe, comprising hundreds to thousands of galaxies bound together by gravity. The developing cluster, or protocluster, is seen as it looked 13 billion years ago. Presumably, it has grown into one of today's massive galactic cities, comparable to the nearby Virgo cluster of more than 2,000 galaxies.

"These galaxies formed during the earliest stages of galaxy assembly, when galaxies had just started to cluster together," said Michele Trenti of the University of Colorado at Boulder and the Institute of Astronomy at the University of Cambridge in the United Kingdom.

"The result confirms our theoretical understanding of the buildup of galaxy clusters. And, Hubble is just powerful enough to find the first examples of them at this distance.

"Trenti presented the results today at the American Astronomical Society meeting in Austin, Texas. The study will be published in an upcoming issue of The Astrophysical Journal.

Most galaxies in the universe reside in groups and clusters, and astronomers have probed many mature galactic cities in detail as far as 11 billion light-years away. Finding clusters in the early phases of construction has been challenging because they are rare, dim and widely scattered across the sky.

"We need to look in many different areas because the odds of finding something this rare are very small," said Trenti, who used Hubble's sharp-eyed Wide Field Camera 3 (WFC3) to pinpoint the cluster galaxies.

"The search is hit and miss. Typically, a region has nothing, but if we hit the right spot, we can find multiple galaxies.

"Hubble’s observations demonstrate the progressive buildup of galaxies. They also provide further support for the hierarchical model of galaxy assembly, in which small objects accrete mass, or merge, to form bigger objects over a smooth and steady but dramatic process of collision and collection.

Because the distant, fledgling clusters are so dim, the team hunted for the systems' brightest galaxies. These galaxies act as billboards, advertising cluster construction zones. From computer simulations, the astronomers expect galaxies at early epochs to be clustered together.

Because brightness correlates with mass, the most luminous galaxies pinpoint the location of developing clusters. These powerful light beacons live in deep wells of dark matter, an invisible form of matter that makes up the underlying gravitational scaffolding for construction.

The team expects many fainter galaxies that were not seen in these observations to inhabit the same neighborhood.The five bright galaxies spotted by Hubble are about one-half to one-tenth the size of our Milky Way, yet are comparable in brightness.

The galaxies are bright and massive because they are being fed large amounts of gas through mergers with other galaxies. The team's simulations show that the galaxies eventually will merge and form the brightest central galaxy in the cluster, a giant elliptical similar to the Virgo Cluster's M87.

The observations are part of the Brightest of Reionizing Galaxies survey, which uses Hubble's WFC3 to search for the brightest galaxies around 13 billion years ago, when light from the first stars burned off a fog of cold hydrogen in a process called reionization.

The team estimated the distance to the newly found galaxies based on their colors, but the astronomers plan to follow up with spectroscopic observations, which measure the expansion of space.

Those observations will help astronomers precisely calculate the cluster's distance and yield the velocities of the galaxies, which will show whether they are gravitationally bound to each other. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.
NASA.

http://www.nasa.gov/mission_pages/hubble/science/far-protocluster.html

Guillermo Gonzalo Sánchez Achutegui

ayabaca@gmail.com

ayabaca@hotmail.com

ayabaca@yahoo.com

Astronomy: Hubble Solves Mystery on Source of Supernova in Nearby Galaxy

Hi My Friends: AL VUELO DE UN QUINDE EL BLOG., Using NASA's Hubble Space Telescope, astronomers have solved a longstanding mystery on the type of star, or so-called progenitor, which caused a supernova seen in a nearby galaxy. The finding yields new observational data for pinpointing one of several scenarios that trigger such outbursts.This image of Type Ia Supernova Remnant 0509-67.5 was made by combining data from two of NASA’s Great Observatories. The result shows soft green and blue hues of heated material from the X-ray data surrounded by the glowing pink optical shell, which shows the ambient gas being shocked by the expanding blast wave from the supernova. Credit: NASA, ESA, and B. Schaefer and A. Pagnotta (Louisiana State University, Baton Rouge); Image Credit: NASA, ESA, CXC, SAO, the Hubble Heritage Team (STScI/AURA), J. Hughes (Rutgers University)

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Based on previous observations from ground-based telescopes, astronomers knew the supernova class, called a Type Ia, created a remnant named SNR 0509-67.5, which lies 170,000 light-years away in the Large Magellanic Cloud galaxy.

Theoretically, this kind of supernova explosion is caused by a star spilling material onto a white dwarf companion, the compact remnant of a normal star, until it sets off one of the most powerful explosions in the universe.

Astronomers failed to find any remnant of the companion star, however, and concluded that the common scenario did not apply in this case, although it is still a viable theory for other Type Ia supernovae.

"We know Hubble has the sensitivity necessary to detect the faintest white dwarf remnants that could have caused such explosions," said lead investigator Bradley Schaefer of Louisiana State University (LSU) in Baton Rouge.

"The logic here is the same as the famous quote from Sherlock Holmes: 'when you have eliminated the impossible, whatever remains, however improbable, must be the truth.'"The cause of SNR 0509-67.5 can be explained best by two tightly orbiting white dwarf stars spiraling closer and closer until they collided and exploded.

For four decades, the search for Type Ia supernovae progenitors has been a key question in astrophysics. The problem has taken on special importance during the last decade with Type Ia supernovae being the premier tools for measuring the accelerating universe.

Type Ia supernovae release tremendous energy, in which the light produced is often brighter than an entire galaxy of stars. The problem has been to identify the type of star system that pushes the white dwarf's mass over the edge and triggers this type of explosion. Many possibilities have been suggested, but most require that a companion star near the exploding white dwarf be left behind after the explosion.

Therefore, a possible way to distinguish between the various progenitor models has been to look deep in the center of an old supernova remnant to search for the ex-companion star.

In 2010, Schaefer and Ashley Pagnotta of LSU were preparing a proposal to look for any faint ex-companion stars in the center of four supernova remnants in the Large Magellanic Cloud when they discovered the Hubble Space Telescope already had taken the desired image of one of their target remnants, SNR 0509-67.5, for the Hubble Heritage program, which collects images of especially photogenic astronomical targets.

In analyzing the central region, they found it to be completely empty of stars down to the limit of the faintest objects Hubble can detect in the photos. Schaefer suggests the best explanation left is the so-called "double degenerate model" in which two white dwarfs collide.

The results are being reported today at the meeting of the American Astronomical Society in Austin, Texas. A paper on the results will be published in the Jan. 12 issue of the journal Nature.

There are no recorded observations of the star exploding. However, researchers at the Space Telescope Science Institute in Baltimore, Md. have identified light from the supernova that was reflected off of interstellar dust, delaying its arrival at Earth by 400 years. This delay, called a light echo of the supernova explosion also allowed the astronomers to measure the spectral signature of the light from the explosion.

By virtue of the color signature, astronomers were able to deduce it was a Type Ia supernova.

Because the remnant appears as a nice symmetric shell or bubble, the geometric center can be determined accurately. These properties make SNR 0509-67.5 an ideal target to search for ex-companions. The young age also means that any surviving stars have not moved far from the site of the explosion.

The team plans to look at other supernova remnants in the Large Magellenic Cloud to further test their observations.

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

NASA.

http://www.nasa.gov/mission_pages/hubble/science/supernova-source.html

Guillermo Gonzalo Sánchez Achutegui

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