Posted on by Nancy Atkinson

Hubble NICMOS Instrument Experiences Anomaly

NICMOS

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A cooling system for the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) science instrument aboard the Hubble telescope experienced an anomaly during a restart, causing the instrument to go into safe mode. After a couple of additional restarts, the problem still persists, and a decision was made for NICMOS to “stand down” while engineers study the anomaly and allow the cooling system to warm up, which may take a couple of weeks. In the short term, this will affect planned science observations, and engineers are hoping to avoid any long term complications. At this point, if the problem cannot be fixed from the ground, it is unclear how it might affect the upcoming servicing mission, scheduled for an Oct. 10 launch.

New software was uploaded last week to the computer that controls Hubble’s five science instruments to get the telescope ready for the upcoming servicing mission (SM4). Installation of the software requires putting all of the telescope’s science instruments into safe mode configuration for a short period of time.

About six hours after the system was reactivated, at about 4 a.m. EDT on Sept. 11, the NICMOS anomaly was seen. The cooling system put itself into safe mode after seeing too high a speed in the circulator pump operation. After studying data, flight controllers modified operating protection parameters and attempted a restart of the system on Sunday, Sept. 14. The circulator system again indicated a high speed violation so the system was returned to safe mode.

Engineers believe the ice particles in the cooling loop could be causing the problem. With some small adjustments in start-up procedures, engineers think the cooling system can be successfully reactivated. The flight team tried another restart Monday evening (9/15). The anomaly was still seen after that restart, so the Hubble Project’s plan now is to stand down from any additional attempts to restart. Engineers will study the anomaly while waiting until the cooling system has been allowed to warm somewhat, which may take several weeks.

The impact to planned NICMOS science operations involves approximately 70 exposures from three guest observer programs and additional exposures from two NICMOS internal calibration programs. Additionally, all NICMOS science has been removed from this week’s observation schedule. Sixty-one orbits of NICMOS science were scheduled for the week between September 15 and September 21.

The servicing mission already has a jam-packed schedule, and its uncertain if any last minute additions to the mission would be possible.

Source: NASA

Posted on by Nancy Atkinson

Do All Galaxies Have Tentacles?

This Hubble Space Telescope image of two spiral galaxies shows an interesting feature on the smaller galaxy. Silhouetted in front of the larger background galaxy is a small galaxy, and tentacles of dust can be seen extending beyond the small galaxy’s disk of starlight. These dark, dusty structures appear to be devoid of stars, almost like barren branches. They are rarely so visible in a galaxy because there is usually nothing behind them but darkness. But here, with the backdrop of the larger galaxy they are illuminated. Astronomers have never seen dust this far beyond the visible edge of a galaxy, and they don’t know if these dusty structures are common features in galaxies.

The background galaxy is 780 million light-years away, but the distance between the two galaxies has not yet been calculated. Astronomers think the two are relatively close, but not close enough to actually interact. The background galaxy is about the size of the Milky Way Galaxy and is about 10 times larger than the foreground galaxy. Understanding a galaxy’s color and how dust affects and dims that color are crucial to measuring a galaxy’s true brightness. By knowing the true brightness, astronomers can calculate the galaxy’s distance from Earth.

Most of the stars speckled across this image belong to the nearby spiral galaxy NGC 253, which is out of view to the right. Astronomers used Hubble’s Advanced Camera for Surveys to snap images of NGC 253 when they spied the two galaxies in the background. From ground-based telescopes, the two galaxies look like a single blob. But the Advanced Camera’s sharp “eye” distinguished the blob as two galaxies, cataloged as 2MASX J00482185-2507365. The images were taken on Sept. 19, 2006.

Source: Hubblesite

Posted on by Nancy Atkinson

Clash of Clusters Separates Dark Matter From Ordinary Matter

Credit: X-ray(NASA/CXC/Stanford/S.Allen); Optical/Lensing(NASA/STScI/UC Santa Barbara/M.Bradac)

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A powerful collision of galaxy clusters captured by NASA’s Hubble Space Telescope and Chandra X-ray Observatory provides evidence for dark matter and insight into its properties. Observations of the cluster known as MACS J0025.4-1222 indicate that a titanic collision has separated dark matter from ordinary matter. The images also provide an independent confirmation of a similar effect detected previously in a region called the Bullet Cluster. Like the Bullet Cluster, this newly studied cluster shows a clear separation between dark and ordinary matter.

MACS J0025 formed after an enormously energetic collision between two large clusters. Using visible-light images from Hubble, the team was able to infer the distribution of the total mass — dark and ordinary matter. Hubble was used to map the dark matter (colored in blue) using a technique known as gravitational lensing. The Chandra data enabled the astronomers to accurately map the position of the ordinary matter, mostly in the form of hot gas, which glows brightly in X-rays (pink).

As the two clusters that formed MACS J0025 (each almost a whopping quadrillion times the mass of the Sun) merged at speeds of millions of miles per hour, the hot gas in the two clusters collided and slowed down, but the dark matter passed right through the smashup. The separation between the material shown in pink and blue therefore provides observational evidence for dark matter and supports the view that dark-matter particles interact with each other only very weakly or not at all, apart from the pull of gravity.

On the Chandra website, there are two animations, one that shows the different views of this cluster viewed by the different observatories, and another depicting how the galaxies may have collided.

Bullet Cluster. Credit: NASA/CXC/CfA/STScI
Bullet Cluster. Credit: NASA/CXC/CfA/STScI

These new results show that the Bullet Cluster is not an anomalous case and helps answers questions about how dark matter interacts with itself.

Sources: HubbleSite, Chandra

Posted on by Nancy Atkinson

Hubble Spies Beautiful, Beastly Monster Galaxy

Complete with tentacles, a supermassive black hole and x-ray emitting gas, a monster of a galaxy has been found by NASA’s Hubble Space Telescope, and is helping astronomers answer a long-standing puzzle. The very active galaxy NGC 1275 has giant but beautiful and delicate filaments influenced and shaped by a beastly-strong extragalactic magnetic field. But how the delicate structures such as those found in this galaxy can withstand the hostile, high-energy environment has been a mystery. But researchers say the beauty and the beast co-exist and are dependent on each other for survival.

One of the closest giant elliptical galaxies, NGC 1275 hosts a supermassive black hole. Energetic activity of gas swirling near the black hole blows bubbles of material into the surrounding galaxy cluster. Long gaseous filaments stretch out beyond the galaxy, into the multimillion-degree, X-ray–emitting gas that fills the cluster. Astronomers thought these delicate filaments should have heated up, dispersed, and evaporated by now, or collapsed under their own gravity to form stars.

These filaments are the only visible-light manifestation of the intricate relationship between the central black hole and the surrounding cluster gas. They provide important clues about how giant black holes affect their surrounding environment.

Using Hubble’s view, a team of astronomers led by Andy Fabian from the University of Cambridge, UK, have for the first time resolved individual threads of gas that make up the filaments. The amount of gas contained in a typical thread is around one million times the mass of our own Sun. They are only 200 light-years wide, are often very straight, and extend for up to 20,000 light-years. The filaments are formed when cold gas from the core of the galaxy is dragged out in the wake of the rising bubbles blown by the black hole.

A new study published in the August 21 Nature magazine proposes that magnetic fields hold the charged gas in place and resist the forces that would distort the filaments. This skeletal structure is strong enough to resist gravitational collapse.

“We can see that the magnetic fields are crucial for these complex filaments – both for their survival and for their integrity,” said Fabian.

Similar networks of filaments are found around other more remote central cluster galaxies. However, they cannot be observed with comparable resolution to the view of NGC 1275. In future observations, the team will apply the understanding of NGC 1275 to interpret what they see in other, more distant galaxies.

News Source: Hubble Site

Posted on by Nancy Atkinson

Hubble’s Odometer Hits 100,000 Orbits

Hubble's 100,000th Orbit Celebration Image. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

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This morning at 7:42 EDT, the Hubble Space Telescope completed it’s 100,000th orbit around the Earth. That’s about 4.38 billion kilometers (2.72 billion miles), as it clicks along at 8 km per second (5 miles/s), orbiting Earth once every 90 minutes. Hubble’s been in orbit for over 18 years now, since its launch on the space shuttle Discovery on April 24, 1990. To commemorate occasion, scientists at the Space Telescope Science Institute in Baltimore, Md., released a special image taken with Hubble’s Wide Field Planetary Camera 2 of a nebula near the star cluster NGC 2074 (upper, left) , showing a dazzling region of celestial birth and renewal. And soon, Hubble will have a little renewal of its own, with the upcoming fifth and final servicing mission in October.

In preparation for the STS-125 servicing mission to Hubble, on Friday engineers mated the external tank (ET-127) to the two solid rocket boosters. Things are going well with getting Atlantis ready to go, and NASA is looking at actually moving up the launch date for the mission a few days, from the currently scheduled October 8 to October 2. Read more about the mission here, and interviews with the seven astronauts who will be part of the mission are available to read on that page, or you can watch them on NASA TV this week.

The above image released today shows a firestorm of raw stellar creation, perhaps triggered by a nearby supernova explosion. It lies about 170,000 light-years away near the Tarantula nebula, one of the most active star-forming regions in our Local Group of galaxies. This representative color image was taken just yesterday on August 10, 2008. Red shows emission from sulfur atoms, green from glowing hydrogen, and blue from glowing oxygen.

Hubble remains in orbit without any fuel; it just uses its speed and Earth’s gravity to maintain its circular orbit, and gyroscopes to maintain the correct attitude. The astronauts on Atlantis will make one final mechanic’s check to replace worn gyroscopes, batteries and a fine guidance sensor and to install new instruments to extend Hubble’s vision. These include a new Wide Field Camera 3 and a Cosmic Origins Spectrograph, to observe the light put out by extremely faint, far-away quasars.

Hubble has been an incredible spacecraft that has changed our view of the universe. Happy 100,000th orbit Hubble!

Source: Hubblesite

Posted on by Nancy Atkinson

Hubble Survey of Gravitational Lenses Yields Measure of Dark Matter in Distant Galaxies

Hubble Space Telescope image shows Einstein ring of one of the SLACS gravitational lenses, with the lensed background galaxy enhanced in blue. A. Bolton (UH/IfA) for SLACS and NASA/ESA.

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An international team of astronomers have compiled the largest-ever single collection of “gravitational lens” galaxies, and their survey yielded information on the masses of galaxies, including an inference of the amount of dark matter. Gravitational lensing occurs when two galaxies happen to aligned with one another along our line of sight in the sky. The gravitational field of the nearer galaxy distorts the image of the more distant galaxy into multiple arc-shaped images. Sometimes this effect even creates a complete ring, known as an “Einstein Ring.” The findings of this survey helps settle a long standing debate over the relationship between and mass and luminosity in galaxies.

Using the Advanced Camera for Surveys on the Hubble Space Telescope to image galaxies that had been identified as gravitational lens galaxies by the Sloan Digital Sky Survey, the team was able to measure the distances to both galaxies in each “lensing” set, as well as measure the masses of each galaxy.

Gravitational lensing creates a “mirage” of a ring, and the Einstein ring images can be up to 30 times brighter than the image of the distant galaxy would be in the absence of the lensing effect. By combining Hubble and Sloan data into the Sloan Lens ACS (or SLACS) Survey, the team was able to make a mathematical model describing the lensing effect and use that model to illustrate what we would see if we could remove the lensing effect.

Animation of the lensing effect.

“The SLACS collection of lenses is especially powerful for science,” said Adam Bolton from the University of Hawaii, lead author of two papers describing these latest results. “For each lens, we measured the apparent sizes of the Einstein rings on the sky using the Hubble images, and we measured the distances to the two galaxies of the aligned pair using Sloan data. By combining these measurements, we were able to deduce the mass of the nearer galaxy.”

By considering these galaxy masses along with measurements of their sizes, brightnesses, and stellar velocities, the SLACS astronomers were able to infer the presence of “dark matter” in addition to the visible stars within the galaxies. Dark matter is the mysterious, unseeable material that is the majority of matter in the universe. And with such a large number of lens galaxies across a range of masses, they found that the fraction of dark matter relative to stars increases systematically when going from galaxies of average mass to galaxies of high mass.

Mosaic of the SLACS galaxies. Credit: SLACS and NASA/ESA.
Mosaic of the SLACS galaxies. Credit: SLACS and NASA/ESA.

Albert Einstein predicted the existence of gravitational lenses in the 1930’s, but the first example was not discovered until the late 1970s. Since then, many more lenses have been discovered, but their scientific potential has been limited by the disparate assortment of known examples. The SLACS Survey has significantly changed this situation by discovering a single large and uniformly selected sample of strong lens galaxies. The SLACS collection promises to form the basis of many further scientific studies.

Original News Source: University of Hawaii

Posted on by Nancy Atkinson

“Baby Red Spot” May Have Met Demise on Jupiter

The Great Red Spot on Jupiter has been observed for over 150 years, and it doesn’t appear this anti-cyclonic storm is showing any signs of letting up. How does it maintain its power? Well, like a planetary Pac-Man, it “eats up” other storms, zapping them of their power. The sequence of images here from the Hubble Space Telescope shows three different storms on Jupiter: The Great Red Spot, Red Spot Jr. (otherwise known as Oval BA, to the south of GRS), and Baby Red Spot, to the left of GRS in the first two images. Baby got a little too close to big brother GRS, and may have been snuffed out. But GRS keeps on keeping on. These three natural-color Jupiter images were made from data acquired on May 15, June 28, and July 8, 2008, by the Hubble’s Wide Field Planetary Camera 2.

Red Spot Jr. first appeared on Jupiter in early 2006 when a previously white storm turned red. This is the second time, since turning red, it has skirted past its big brother apparently unscathed. More on Jr. or Oval BA over at the BA himself, Phil Plait’s Bad Astronomy.

But poor little Baby Red Spot, which is in the same latitudinal band as the GRS. This new red spot first appeared earlier this year. The baby spot gets ever closer to the GRS in this picture sequence until it is caught up in GRS’s anticyclonic spin. In the final image the baby spot is deformed and pale in color and has been spun to the right (east) of the GRS. The prediction is that the baby spot will now get pulled back into the GRS “Cuisinart” and disappear for good. This is one possible mechanism that has powered and sustained the GRS for at least 150 years.

Each image covers 58 degrees of Jovian latitude and 70 degrees of longitude (centered on 5 degrees South latitude and 110, 121, and 121.

Original News Source: HubbleSite

Posted on by Nancy Atkinson

Baby Boomer Galaxy Found

This galaxy, Zw II 96 (about 500 million light-years away) resembles the Baby Boom galaxy which lies about 12.3 billion light-years away and appears in images as only a smudge.

A group of telescopes got together recently to check out a little hanky-panky going on in a galaxy in a very remote part of the universe. The Hubble and Spitzer Space Telescopes, Japan’s Subaru Telescope, the James Clerk Maxwell and the Keck Telescopes, all on Mauna Kea in Hawaii, and the Very Large Array in New Mexico pooled their various optical, infrared, submillimeter and radio capabilities to see why a distant galaxy appears to be conceiving stars at a tremendously fast rate. This galaxy, which has now been dubbed the “Baby Boom” galaxy, is giving birth to about 4,000 stars per year. In comparison, our own Milky Way galaxy turns out an average of just 10 stars per year. These telescopes weren’t just playing the part of a Peeping Tom; astronomers want to find out more about this incredibly fertile galaxy.

“This galaxy is undergoing a major baby boom, producing most of its stars all at once,” said Peter Capak of NASA’s Spitzer Science Center at the California Institute of Technology, Pasadena. “If our human population was produced in a similar boom, then almost all of the people alive today would be the same age.”

The discovery goes against the most common theory of galaxy formation, the Hierarchical Model. According to the theory galaxies slowly bulk up their stars over time, and not in one big burst as “Baby Boom” appears to be doing.

The Baby Boom galaxy, which belongs to a class of galaxies called starbursts, is the new record holder for the brightest starburst galaxy in the very distant universe, with brightness being a measure of its extreme star-formation rate. It was discovered and characterized using a suite of telescopes operating at different wavelengths. NASA’s Hubble Space Telescope and Japan’s Subaru Telescope, atop Mauna Kea in Hawaii, first spotted the galaxy in visible-light images, where it appeared as an inconspicuous smudge due to is great distance.

It wasn’t until Spitzer and the James Clerk Maxwell Telescope, also on Mauna Kea in Hawaii, observed the galaxy at infrared and submillimeter wavelengths, respectively, that the galaxy stood out as the brightest of the bunch. This is because it has a huge number of youthful stars. When stars are born, they shine with a lot of ultraviolet light and produce a lot of dust. The dust absorbs the ultraviolet light but, like a car sitting in the sun, it warms up and re-emits light at infrared and submillimeter wavelengths, making the galaxy unusually bright to Spitzer and the James Clerk Maxwell Telescope.

To learn more about this galaxy’s unique youthful glow, Capak and his team followed up with a number of telescopes. They used optical measurements from Keck to determine the exact distance to the galaxy — a whopping12.3 billion light-years. That’s looking back to a time when the universe was 1.3 billion years old (the universe is approximately 13.7 billion years old today).

The astronomers made measurements at radio wavelengths with the National Science Foundation’s Very Large Array in New Mexico. Together with Spitzer and James Clerk Maxwell data, these observations allowed the astronomers to calculate a star-forming rate of about 1,000 to 4,000 stars per year. At that rate, the galaxy needs only 50 million years, not very long on cosmic timescales, to grow into a galaxy equivalent to the most massive ones we see today.

“Before now, we had only seen galaxies form stars like this in the teenaged universe, but this galaxy is forming when the universe was only a child,” said Capak. “The question now is whether the majority of the very most massive galaxies form very early in the universe like the Baby Boom galaxy, or whether this is an exceptional case. Answering this question will help us determine to what degree the Hierarchical Model of galaxy formation still holds true.”

“The incredible star-formation activity we have observed suggests that we may be witnessing, for the first time, the formation of one of the most massive elliptical galaxies in the universe,” said co-author Nick Scoville of Caltech.

Original News Source: JPL

Posted on by Nancy Atkinson

Hubble Does Independence Day With Stars and Stripe

Back in 1006 A.D, observers from Africa to Europe to the Far East witnessed and recorded the arrival of light from what is now called SN 1006, a tremendous supernova explosion caused by the final death throes of a white dwarf star nearly 7,000 light-years away. One Egyptian astronomer recorded the object was 2 – 3 times as large as the disc of Venus and about one quarter the brightness of the moon. The supernova was probably the brightest star ever seen by humans, visible even during the day for weeks, and it remained visible to the naked eye for at least two and a half years before fading away. Remnants of this supernova are still visible to telescopes, and the Hubble Space Telescope captured this close-up a filament of the shock wave of the explosion, still reverberating through space, seen here against the grid of background stars. The full image of SN 1006 is pretty impressive, too…

SN 1006 has a diameter of nearly 60 light-years, and it is still expanding at roughly 6 million miles per hour. Even at this tremendous speed, however, it takes observations typically separated by years to see significant outward motion of the shock wave against the grid of background stars. In the Hubble image shown here, the supernova would have occurred far off the lower right corner of the image, and the motion would be toward the upper left.

It wasn’t until the mid-1960s that radio astronomers first detected a nearly circular ring of material at the recorded position of the supernova. The ring was almost 30 arcminutes across, the same angular diameter as the full moon. The size of the remnant implied that the blast wave from the supernova had expanded at nearly 20 million miles per hour over the nearly 1,000 years since the explosion occurred.

In 1976, the first detection of exceedingly faint optical emission of the supernova remnant was reported, but only for a filament located on the northwest edge of the radio ring. A tiny portion of this filament is revealed in detail by the Hubble observation. The twisting ribbon of light seen by Hubble corresponds to locations where the expanding blast wave from the supernova is now sweeping into very tenuous surrounding gas.

The hydrogen gas heated by this fast shock wave emits radiation in visible light. Hence, the optical emission provides astronomers with a detailed “snapshot” of the actual position and geometry of the shock front at any given time. Bright edges within the ribbon correspond to places where the shock wave is seen exactly edge on to our line of sight.

Original News Source: HubbleSite

Posted on by Nancy Atkinson

Hubble Zooms In On Coma Galaxy Cluster

The Coma Cluster is one of the densest known clusters of galaxies, containing thousands of elliptical and spherical star systems. The entire cluster is huge, more than 20 million light-years in diameter. It’s also very far away, over 300 million light years distant. But no telescope brings the Coma Cluster closer than the Hubble Space Telescope, and a new Hubble image has captured the magnificent starry population in one area of the Coma Cluster with the Advanced Camera for Surveys.

The above Hubble image focuses on an area that is roughly one-third of the way out from the center of the whole cluster. One bright spiral galaxy is visible in the upper left of the image (see below for a close-up of this galaxy). It is distinctly brighter and bluer than the galaxies surrounding it. A series of dusty spiral arms appears reddish brown against the whiter disc of the galaxy, and suggests that this galaxy has been disturbed at some point in the past. The other galaxies in the image are either elliptical galaxies, S0 (s-zero) galaxies or background galaxies that are far beyond the Coma Cluster sphere.

Ellipticals are featureless “fuzz-balls,” pale golden brown in color and contain populations of old stars. Both dwarf and giant ellipticals are found in abundance in the Coma Cluster.

Farther out from the centre of the cluster there are several spiral galaxies. These galaxies contain clouds of cold gas that are giving birth to new stars. Spiral arms and dust lanes “accessorise” these bright bluish-white galaxies, which have a distinctive disc structure.

S0 (S-zero) galaxies form a morphological class of objects between the better known elliptical and spiral galaxies. They consist of older stars and show little evidence of recent star formation, but they do show some structure — perhaps a bar or a ring that may eventually give rise to more disc-like features.


This image zooms in on one area of the new Hubble image, the stunning Lenticular galaxy (in the lower left of the first image) with numerous background galaxies visible as well.

The cluster’s position in space – near the Milky Way’s north pole— places it in an area not obscured by dust and gas, making it easily visible from Earth.

Original News Source: Hubble Site