Tag: Hubble

A bubbly dwarf galaxy

9:09 am

A bubbly dwarf galaxy
Click for original image.

Cool image time! The picture to the right, cropped and reduced to post here, was released today by the science team of the Hubble Space Telescope, and shows an irregular dwarf galaxy that is about seven million light years away.

Twelve camera filters were combined to produce this image, with light from the mid-ultraviolet through to the red end of the visible spectrum. The red patches are likely interstellar hydrogen molecules that are glowing because they have been excited by the light from hot, energetic stars. The other sparkles on show in this image are a mix of older stars. An array of distant, diverse galaxies appear in the background, captured by Hubble’s sharp view.

The data used in this image were taken by Hubble’s Wide Field Camera 3 and the Advanced Camera for Surveys from 2006 to 2021.

The picture was taken as part of a study of dwarf galaxies, their make-up, and how their mergers eventually create the larger galaxies like the Milky Way.

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A galaxy of violence

9:53 am

A galaxy of violence
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Time for another cool image! The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope, and shows a well defined spiral galaxy face-on in optical wavelengths.

This whirling image features a bright spiral galaxy known as MCG-01-24-014, which is located about 275 million light-years from Earth. In addition to being a well-defined spiral galaxy, MCG-01-24-014 has an extremely energetic core, known as an active galactic nucleus (AGN), so it is referred to as an active galaxy. Even more specifically, it is categorised as a Type-2 Seyfert galaxy. Seyfert galaxies host one of the most common subclasses of AGN, alongside quasars. Whilst the precise categorisation of AGNs is nuanced, Seyfert galaxies tend to be relatively nearby ones where the host galaxy remains plainly detectable alongside its central AGN, while quasars are invariably very distant AGNs whose incredible luminosities outshine their host galaxies.

In contrast, the core of our own Milky Way galaxy is very quiet, which is likely a factor in why it was possible for life to form on Earth.

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Galaxies in a row

9:18 am

Galaxies in a row
Click for original image.

Cool image time from Hubble! The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope as part of a survey of nearby “pecular” galaxies. What makes it unusual is the line of distant galaxies below the largest on the left.

The wonderful quality of this image also reveals several further galaxies, not associated with this system but fortuitously positioned in such a way that they appear to be forming a line that approaches the leftmost (in this image) component of Arp-Madore 2105-332, which is known individually as 2MASX J21080752-3314337. The rightmost galaxy, meanwhile, is known as 2MASX J21080362-3313196. These hefty names do not lend themselves to easy memorisation, but they do actually contain valuable information: they are coordinates in the right ascension and declination system used widely by astronomers to locate astronomical objects.

Both larger galaxies are thought to be about 200 million light years away, with the smaller ones far more distant. If you look at the full resolution image, you will see that there are at least six galaxies in that line, one that appears to be an elliptical galaxy with all the rest a variety of different types of spiral galaxies. The detail provided by Hubble is truly astonishing.

Though they are not linked to the larger galaxies, it is not clear if they are linked to each other.

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Hubble to resume science operations using three gyros

9:02 am

Engineers have apparently figured out the issues with one of the Hubble Space Telescope’s three gyroscopes, and plan to resume science operations today using all three gyros.

After analyzing the data, the team has determined science operations can resume under three-gyro control. Based on the performance observed during the tests, the team has decided to operate the gyros in a higher-precision mode during science observations. Hubble’s instruments and the observatory itself remain stable and in good health.

This is excellent news. If it had been determined that the funky gyro was no longer functional, the telescope would have shifted into what the engineers call “one-gyro mode.” By using only one of the two remaining gyros, Hubble’s life could be extended. However, while it would allow the telescope to point and continue observations, the images would no longer be as sharp.

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Hubble in safe mode due to gyroscope problem

8:58 am

One of the three working gyroscopes (three have already failed0 on the Hubble Space Telescope experienced repeated problems in mid-November, and has now put the telescope in safe mode while engineers trouble-shoot the problem.

Hubble first went into safe mode Nov. 19. Although the operations team successfully recovered the spacecraft to resume observations the following day, the unstable gyro caused the observatory to suspend science operations once again Nov. 21. Following a successful recovery, Hubble entered safe mode again Nov. 23.

The team is now running tests to characterize the issue and develop solutions. If necessary, the spacecraft can be re-configured to operate with only one gyro. The spacecraft had six new gyros installed during the fifth and final space shuttle servicing mission in 2009. To date, three of those gyros remain operational, including the gyro currently experiencing fluctuations. Hubble uses three gyros to maximize efficiency, but could continue to make science observations with only one gyro if required.

The long term plan when the telescope only has two working gyros, assuming no improvised maintenance mission is flown to Hubble to give it new gyroscopes, is to work with only one (treating the second as a back-up) in order to extend the telescope’s life as long as possible.

And though it is true that Hubble could continue to do science with only one gyro, images from that point will likely not be as sharp, and thus will end more than three decades of imagery that changed our perception of the universe.

The Chinese 2-meter Xuntian optical space telescope, now scheduled for launch in 2025, will likely then replace Hubble as the world’s top optical telescope. American astronomers better start learning Chinese, assuming China even allows them access. They will not have a right to complain, however, as it was their decision to not build a Hubble replacement, in their 2000, 2010, and 2020 decadal reports.

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Galaxies within galaxies within galaxies

9:54 am

Galaxies within galaxies
Click for original image.

Time another cool galaxy image! The picture to the right, cropped, reduced, sharpened, and annotated to post here, was taken by the Hubble Space Telescope as part of a survey project of galaxies where past supernovae had occurred. From the caption:

The location of this faded supernova was observed as part of a study of multiple hydrogen-rich supernovae, also known as type II supernovae, in order to better understand the environments in which certain types of supernovae take place.

Though the picture’s resolution was reduced to post here, I have also included insets at the full released resolution of three of background galaxies, one of which (on the uppermost right) appears to have a second smaller galaxy either associated with it or is another background galaxy even farther away. Such background galaxies are always seen Hubble images, which starkly tell us that the universe is far vaster than we can imaging, with more stars than we can conceive.

The galaxy featured here is interesting in its own right. Though it appears to be a spiral galaxy, its arms are very indistinct, suggesting that is sits between that of an elliptical galaxy (no arms, just a cloud of stars) and a spiral (with well-defined arms).

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Hubble snaps an ultra-violet view of Jupiter

9:59 am

Jupiter in ultra-violet

Cool image time! Using the Hubble Space Telescope, scientists have taken a false-color ultra-violet image of Jupiter. That picture is to the right, cropped, reduced and sharpened to post here.

This newly released image from the NASA Hubble Space Telescope shows the planet Jupiter in a color composite of ultraviolet wavelengths. Released in honor of Jupiter reaching opposition, which occurs when the planet and the Sun are in opposite sides of the sky, this view of the gas giant planet includes the iconic, massive storm called the “Great Red Spot.” Though the storm appears red to the human eye, in this ultraviolet image it appears darker because high altitude haze particles absorb light at these wavelengths. The reddish, wavy polar hazes are absorbing slightly less of this light due to differences in either particle size, composition, or altitude.

The data used to create this ultraviolet image is part of a Hubble proposal that looked at Jupiter’s stealthy superstorm system. The researchers plan to map deep water clouds using the Hubble data to define 3D cloud structures in Jupiter’s atmosphere.

By comparing this ultra-violet image with Hubble’s optical view as well as Webb’s infrared view, scientists can study Jupiter’s atmosphere much like meteologists study the Earth’s, using multi-wave satellite observations.

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A spiral galaxy giving birth to a lot of stars

10:01 am

A spiral galaxy giving birth to a lot of stars
Click for original image.

Time for another cool galaxy image! The picture to the right, reduced and sharpened to post here, was taken by the Hubble Space Telescope, and shows what some informally refer to as the “‘Spanish Dancer Galaxy’ because the “vivid and dramatic swirling lines of its spiral arms … evoke the shapes and colours of a dancer’s moving form. ”

Though this galaxy’s two main arms cause it to resemble a barred galaxy, it lacks a central bar, suggesting it is young. The numerous reddish and pink regions in the arms, all of which are thought to be star-forming regions, also suggest the galaxy is young, still giving birth to many stars.

It is located about 60 million light years away, and is part of what scientists label the Doradus galaxy group, which contains less than a hundred galaxies. In comparison, a galaxy cluster is much larger, containing hundreds to thousands of galaxies.

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An infrared view of the Crab Nebula by Webb

9:14 am

Webb's image of the Crabb compared to Hubble's
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Using the Webb Space Telescope astronomers have taken the first detailed infrared image of the Crab Nebula, the remnant from a supernova that occurred in 1054 AD.

The two pictures on the right compare Webb’s false color infrared view with a natural light Hubble image in optical wavelengths, taken in 2005. From the press release:

The supernova remnant is comprised of several different components, including doubly ionized sulfur (represented in red-orange), ionized iron (blue), dust (yellow-white and green), and synchrotron emission (white). In this image, colors were assigned to different filters from Webb’s NIRCam and MIRI: blue (F162M), light blue (F480M), cyan (F560W), green (F1130W), orange (F1800W), and red (F2100W).

In comparing the images, it appears the scientists chose colors for the Webb image to more or less match those of Hubble’s natural color picture. However, as the press release notes:

Additional aspects of the inner workings of the Crab Nebula become more prominent and are seen in greater detail in the infrared light captured by Webb. In particular, Webb highlights what is known as synchrotron radiation: emission produced from charged particles, like electrons, moving around magnetic field lines at relativistic speeds. The radiation appears here as milky smoke-like material throughout the majority of the Crab Nebula’s interior.

This feature is a product of the nebula’s pulsar, a rapidly rotating neutron star. The pulsar’s strong magnetic field accelerates particles to extremely high speeds and causes them to emit radiation as they wind around magnetic field lines. Though emitted across the electromagnetic spectrum, the synchrotron radiation is seen in unprecedented detail with Webb’s NIRCam instrument.

The release also notes this remarkable but somewhat unfortunate fact:

Scientists will have newer Hubble data to review within the next year or so from the telescope’s reimaging of the supernova remnant. This will mark Hubble’s first look at emission lines from the Crab Nebula in over 20 years, and will enable astronomers to more accurately compare Webb and Hubble’s findings.

In 2005 repeated Hubble images of the Crab revealed that its filaments and radiation were stormy, with constant activity. The scientists actually produced a movie of those changes. It was expected that new images would be taken at regular intervals to track that activity. Apparently it was not, either because no scientist was interested or the committee that assigns time on Hubble decided this wasn’t important enough reseach.

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A dance of three galaxies

10:40 am

Three galaxies merging
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope. Though it appears to show two galaxies interacting with each other, other spectroscopic data proves there are actually three large galaxies in the picture. From the caption:

The two clearly defined galaxies are NGC 7733 (smaller, lower right) and NGC 7734 (larger, upper left). The third galaxy is currently referred to as NGC 7733N, and can actually be spotted in this picture if you look carefully at the upper arm of NGC 7733, where there is a visually notable knot-like structure, glowing with a different colour to the arm and obscured by dark dust. This could easily pass as part of NGC 7733, but analysis of the velocities (speed, but also considering direction) involved in the galaxy shows that this knot has a considerable additional redshift, meaning that it is very likely its own entity and not part of NGC 7733.

All three galaxies are quite close to each other, which means they are in the long process of merging together into one larger galaxy.

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Astronomers detect nano-sized quartz crystals in atmosphere of exoplanet

9:33 am

Using both the Hubble and Webb space telescopes in space, astronomers have detected nano-sized quartz crystals in the atmosphere of a Jupiter-class exoplanet orbiting its star every 3.7 days.

Silicates (minerals rich in silicon and oxygen) make up the bulk of Earth and the Moon as well as other rocky objects in our solar system, and are extremely common across the galaxy. But the silicate grains previously detected in the atmospheres of exoplanets and brown dwarfs appear to be made of magnesium-rich silicates like olivine and pyroxene, not quartz alone – which is pure SiO2.

The result from this team, which also includes researchers from NASA’s Ames Research Center and NASA’s Goddard Space Flight Center, puts a new spin on our understanding of how exoplanet clouds form and evolve. “We fully expected to see magnesium silicates,” said co-author Hannah Wakeford, also from the University of Bristol. “But what we’re seeing instead are likely the building blocks of those, the tiny ‘seed’ particles needed to form the larger silicate grains we detect in cooler exoplanets and brown dwarfs.”

These tiny quartz crystals are condensing out in the clouds themselves, due to the high temperatures and pressures there. The exoplanet itself is unusual because though its mass is one half that of Jupiter, its volume is seven times larger. This gives it a very large and deep atmosphere, thus providing the environment for crystal formation.

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Astronomers detect baffling blue transient far outside any galaxy

11:32 am

Transient in intergalactic space
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Using a variety of telescopes, astronomers have discovered a baffling short-term object that brightens quickly in blue light and then fades.

What makes this discovery even more baffling is that though other such Luminous Fast Blue Optical Transients (LFBOT) have been discovered, all have been within galaxies, while this new discovery is in intergalactic space, as shown by the red bars in the picture to right, taken by the Hubble Space Telescope and cropped, reduced, and sharpened to post here. From the caption:

[An LFBOT] shines intensely in blue light and evolves rapidly, reaching peak brightness and fading again in a matter of days, unlike supernovae which take weeks or months to dim. Only a handful of previous LFBOTs have been discovered since 2018. The surprise is that this latest transient, seen in 2023, lies at a large offset from both the barred spiral galaxy at right and the dwarf galaxy to the upper left. Only Hubble could pinpoint its location. And, the results are leaving astronomers even more confounded because all previous LFBOTs have been found in star-forming regions in the spiral arms of galaxies. It’s not clear what astronomical event would trigger such a blast far outside of a galaxy.

The frequent discovery of such short term transients in the past decade is because there are now many telescopes dedicated to making daily surveys of the entire sky. In the past such quick events were always missed.

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