Astronomers discover extremely luminous nova

First nova ever found in Small Magellanic Cloud is studied in multiple wavelengths.

What might be one of the most luminous stars ever detected is actually a nova or explosion that occurred in a binary system consisting of a white dwarf and Sun-like star in the Small Magellanic Cloud.

White dwarfs are stellar remnants of stars not massive enough to have died in supernova explosions.

The Small Magellanic Cloud is a satellite galaxy of the Milky Way located about 200,000 light years away.

Using NASA’s Swift satellite, scientists at the University of Leicester discovered the extremely bright nova, caused by the white dwarf’s sucking of material from the regular star until critical pressure was reached, causing the sudden brightness increase.

Led by researchers at the South African Astronomical Observatory, the scientists also observed the nova with ground-based telescopes in several countries, including South Africa, Australia, and South America.

Designated SMCN 2016-10a, the nova, one of the brightest observed in any galaxy, was discovered on October 14, 2016.

The term “nova” means new. Centuries ago, astronomers thought these suddenly bright objects to be new stars as opposed to what they really are–dying old ones.

White dwarfs emit both visible light and high-energy X-rays. By studying their emissions in various wavelengths, scientists can determine their temperatures and compositions.

This is the first time astronomers have spotted a nova in the Small Magellanic Cloud. Approximately 35 are seen in the Milky Way each year.

“Swift’s ability to respond rapidly, together with its daily-planned schedule, makes it ideal for the followup of transients, including novae,” said Swift team X-ray analysis leader Kim Page of the University of Leicester.

“It was able to observe the nova throughout its eruption, starting to collect very useful X-ray and UV data within a day of the outburst first being reported. The X-ray data were essential in showing that the mass of the white dwarf is close to the theoretical maximum; continued accretion might cause it eventually to be totally destroyed in a supernova explosion.”

Paul Kuin of the Mullard Space Science Laboratory at University College London, who organized the UV data, described the ability to observe the nova in multiple wavelengths as key to this being the most comprehensive nova study ever conducted.

Findings of the study have been published in Monthly Notices of the Royal Astronomical Society.

Auroras at Jupiter’s poles act independently

Researchers take advantage of rare opportunity to observe polar regions through Juno mission and space telescopes.

Auroras in Jupiter’s north and south polar regions act independently of one another, according to observations conducted by a study team using the European Space Agency’s (ESA) X-MM-Newton telescope and NASA’s Chandra X-ray Observatory.

Researchers at University College in London and at the Harvard-Smithsonian Center for Astrophysics led a study of high-energy X-ray auroras at both of Jupiter’s poles and were surprised to learn that unlike auroras on the poles of other planets, those at Jupiter’s poles do not mirror one another but pulse independently.

Activities of Earth’s north and south pole auroras mirror one another. Saturn does not appear to experience any X-ray auroras.

X-ray pulses at Jupiter’s south pole occur regularly every 11 minutes while those at its north pole are chaotic, with unpredictable increases and decreases in brightness.

“We didn’t expect to see Jupiter’s X-ray hot spots pulsing independently, as we thought their activity would be coordinated through the planet’s magnetic field,” explained study lead author William Dunn of both UCL Mullard Space Science Laboratory in the UK and the Harvard-Smithsonian Center for Astrophysics.

“We need to study this further to develop ideas for how Jupiter produces its X-ray aurora, and NASA’s Juno mission is really important for this.”

The researchers observed Jupiter using both space observatories in May and June of 2016 and in March 2007 to map the planet’s X-ray emissions and identify X-ray hot spots at its poles.

NASA’s Juno spacecraft, which arrived at Jupiter in 2016, does not have a science instrument capable of detecting X-rays; however, it is collecting other data at the polar regions that scientists hope to combine with the X-MM and Chandra data to better understand the planet’s auroras.

Scientists are fortunate that Juno is studying both of Jupiter’s poles at the same time, making it possible for them to compare activity at the poles with the giant planet’s complex magnetic interactions, emphasized study co-author Graziella Banduardi-Raymont of UCL Space and Climate Physics.

“If we can start to connect the X-ray signatures with the physical processes that produce them, then we can use those signatures to understand other bodies across the universe, such as brown dwarfs, exoplanets, or maybe even neutron stars,” Dunn stated.

One theory the researchers hope to test as they observe Jupiter’s polar activity over the next two years is that the northern and southern auroras form separately as a result of interactions between the planet’s magnetic field and the solar wind.

A paper discussing the findings has been published in the journal Nature Astronomy.

 

Early universe observations reaffirm existence of dark matter and dark energy

New data continues to reaffirm the existence of the inexplicable dark matter and dark energy.

Although dark energy and dark matter are inexplicable, data continues to reaffirm their existence. And with the final data from Europe’s Planck missions released, this continues to be the care.

From 2009 through 2013, the mission mapped the universe’s oldest light in great detail, and the European Space Agency (ESA) claims that the results reaffirm the “standard model of cosmology.”

“This is the most important legacy of Planck,” Jan Tauber, ESA’s Planck project scientist, said in a statement. “So far, the standard model of cosmology has survived all the tests, and Planck has made the measurements that show it.”

The initial release of the data led to some hesitancy, as the team stressed that the results were preliminary.

“We felt the quality of some of the polarization data was not good enough to be used for cosmology,” Tauber said.

But the new release represents a novel method of processing mission data, which lays many doubts to rest.

“Now we really are confident that we can retrieve a cosmological model based solely on temperature, solely on polarization, and based on both temperature and polarization,” said Reno Mandolesi of the University of Ferrara in Italy, a principal investigator of the Low Frequency Instrument (LFI)—one of Planck’s two science instruments. “And they all match.”

Of course, nothing is ever certain when it comes to dark energy and dark matter.

“For the moment, we shouldn’t get too excited about finding new physics; it could well be that the relatively small discrepancy can be explained by a combination of small errors and local effects,” Tauber said. “But we need to keep improving our measurements and thinking about better ways to explain it.”

Astronomers discover new details of ‘monster’ star-forming galaxies

A new study sheds light on the structure of the “monster galaxy” COSMOS-AzTEC-1.

An international team of researchers examining a “monster galaxy” located 12.4 billion light years away from the Earth revealed that they achieved a milestone: an angular resolution 10 times higher than ever before, revealing previously unknown structural details.

“Monster galaxies,” also known as extreme starburst galaxies, are believed to be the ancestors of giant galaxies like the current universe’s Milky Way. And the more we know about them, the more we will discover more about the formation and evolution of our galaxy’s ancient past.

“A real surprise is that this galaxy seen almost 13 billion years ago has a massive, ordered gas disk that is in regular rotation instead of what we had expected, which would have been some kind of a disordered train wreck that most theoretical studies had predicted,” said study co-author Min Yun.

Yun added that they did observe that the galaxy’s gas disk is now dynamically unstable, meaning that the entire disk that makes up the galaxy is undergoing an episode of starburst. This explains its large star formation rate, which is upwards of 1,000 times that of the Milky Way.

Ken-ichi Tadaki, lead author of the study, says that COSMOS-AzTEC-1 is rich in star ingredients. However, it was still difficult to determine the cosmic gas in the galaxy, even using the ALMA’s high sensitivity and high resolution.

“We found that there are two distinct large clouds several thousand light-years away from the center,” he said. “In most distant starburst galaxies, stars are actively formed in the center. So it is surprising to find off-center clouds.”

“How these galaxies have been able to amass such a large quantity of gas in the first place and then essentially turn the entire gas reserve into stars in the blink of an eye, cosmologically speaking, was a completely unknown question about which we could only speculate,” Yun added. “We have the first answers now.”

The findings were published in Nature.

University reports that celebrity astrophysicist Lawrence Krauss grabbed breast

Celebrity astrophysicist Lawrence Krauss is in trouble following a sexual harassment incident.

After being accused of inappropriate behavior, an investigation by Arizona State University (ASU) concluded that high-profile astrophysicist Lawrence Krauss grabbed a women’s breast at a recent conference in Australia and thus violated the university’s sexual harassment policy.

“Responsive action is being taken to prevent any further recurrence of similar conduct,” said ASU’s executive vice president and provost, Mark Searle.

In regards to actions ASU is taking, a spokesperson for the university wrote the following:

“Professor Lawrence Krauss is no longer director of Arizona State University’s Origins Project, a research unit at ASU. Krauss remains on administrative leave from the university. It is the policy of the university not to comment on ongoing personnel matters.”

Krauss just recently announced that his director position on the Origins Project, which attempts to examine the beginnings of the universe, was not renewed for another 5-year term. He was placed on administrative leave on March 6 following sexual harassment allegations.

Microbiologist Melanie Thomson first filed a complaint about the incident, which was initially dismissed due to a lack of evidence.

“They should have believed me the first time,” Thomson said. “It’s ridiculous the amount of effort you have to go through to stop universities from just dismissing these cases. I have been traumatized by the process and I wasn’t even a victim.”

The unnamed woman who was sexually harassed reportedly “reacted with shock and physically moved away” from Krauss, although another eyewitness “body check[ed]” him immediately after he grabbed her breast.

Other eyewitnesses said that they woman was “frazzled and troubled” and “shocked” after the incident.

Rogue planet discovered beyond our solar system

A new study examines a strange rogue planet beyond the Milky Way.

A new study examines a strange rogue planet that is roaming the Milky Way approximately 20 light-years from the sun. The unique nomadic world also has a strong magnetic field that is about 4 million times stronger than the Earth’s.

The team made the observations using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA), marking the first time that scientists have measured the magnetic field of a planetary-mass object outside of our solar system.

The strange object is called SIMP J01365663+0933473 and was first discovered in 2016, when researchers thought it was a brown dwarf star.

“This object is right at the boundary between a planet and a brown dwarf, or ‘failed star,’ and is giving us some surprises that can potentially help us understand magnetic processes on both stars and planets,” Melodie Kao, who led the new study on SIMP, in a press release.

And from here on out, astronomers are hopeful that SIMP will help them continue learning about the universe.

“This particular object is exciting because studying its magnetic dynamo mechanisms can give us new insights on how the same type of mechanisms can operate in extrasolar planets,” Kao said. “We think these mechanisms can work not only in brown dwarfs, but also in both gas giant and terrestrial planets.”

Ultimately, SIMP will help astronomers grasp how magnetic fields are created in exoplanets.

“Detecting SIMP J01365663+0933473 with the VLA through its auroral radio emission also means that we may have a new way of detecting exoplanets, including the elusive rogue ones not orbiting a parent star,” said co-author Gregg Hallinan of Caltech.

The findings were published in The Astrophysical Journal.

Young galaxy’s halo reveals clues to evolution and growth of ancient galaxies

The halo of a young galaxy Q2343-BX418 could shed light on the evolution and growth of the universe’s early galaxies.

Researchers believe that they have discovered a new method of unlocking the mysteries underlying the formation and evolution of the first galaxies. By examining Q2343-BX418, a small young galaxy about 10 billion light years from the Earth, the team believes they can reveal how galaxies looked following the birth of the universe.

Not only that, but the galaxy possesses a gas halo that is emits a certain type of light that is of great interest to astronomers.

“In the last several years, we’ve learned that the gaseous halos surrounding galaxies glow with a particular ultraviolet wavelength called Lyman alpha emission,” said the study’s lead author Dawn Erb. “There are a lot of different theories about what produces this Lyman alpha emission in the halos of galaxies, but at least some of it is probably due to light that is originally produced by star formation in the galaxy being absorbed and re-emitted by gas in the halo.”

“Most of the ordinary matter in the universe isn’t in the form of a star or a planet, but gas,” Erb said. “And most of that gas exists not in galaxies, but around and between them.”

The halo is the location where gas enters and exits the galaxy. It also fuels galaxies, and sometimes the gas within a galaxy can shift into the halo. The process of gas flowing in and out of these regions is what influences stars and their fates.

“The inflow of new gas accreting into a galaxy provides fuel for new star formation, while outflows of gas limit a galaxy’s ability to form stars by removing gas,” Erb said. “So, understanding the complex interactions happening in this gaseous halo is key to finding out how galaxies form stars and evolve.”

Notably, the study harnessed the power of the Keck Cosmic Web Imager (KCWI) from the Keck Observatory.

“Our study was really enabled by the design and sensitivity of this new instrument,” Erb said. “It’s not just an ordinary spectrograph—it’s an integral field spectrograph, which means that it’s a sort of combination camera and spectrograph, where you get a spectrum of every pixel in the image.”

The findings were published in Astrophysical Journal Letters.

Ancient moon life is a possibility, study says

A new study suggests the Earth’s moon could have been habitable 3.5 to 3.8 billion years ago.

Washington State University researchers Dirk Schulze-Makuch and Ian Crawford just released a study that suggests that there are two early windows of time in the lifetime of the Earth’s moon that could have been habitable for life.

“If liquid water and a significant atmosphere were present on the early moon for long periods of time, we think the lunar surface would have been at least transiently habitable,” Schulze-Makuch said.

The team’s work examined data from recent space missions and analyses of soil samples and lunar rock to suggest that the moon is not as dry as we thought. In particular, the team examined fossilized cyanobacteria that suggests that the moon was habitable during their time 3.5 to 3.8 billion years ago.

“It looks very much like the moon was habitable at this time,” Schulze-Makuch said. “There could have actually been microbes thriving in water pools on the moon until the surface became dry and dead.”

The study also suggests potential directions that future moon research can explore.

“In addition, experiments could be conducted in lunar environment simulation chambers in laboratories on Earth to observe whether microorganisms can maintain viability under the environmental conditions predicted to have existed on the early Moon,” the researchers wrote.

“Indeed, the surface conditions predicted by Needham and Kring (2017) are not very different from those routinely produced in Mars simulation chambers,” they continued.

“Thus, we recommend utilizing both Moon simulation chambers on our planet and on the ISS to test whether there might have been an early habitability window on the Moon,” they concluded.

The findings were published in Astrobiology.

Andromeda might have cannibalized our sister galaxy

Scientists believe that Andromeda cannibalized the Milky Way’s sister galaxy about 32 million years ago.

Researchers suggest that the Andromeda galaxy, with its satellite galaxies M110 and M32, cannibalized one of our sister galaxies. The result is M32, which is a remnant of the larger galaxy that was eaten approximately 32 billion year ago.

“Astronomers have been studying the Local Group—the Milky Way, Andromeda and their companions—for so long,” said Eric Bell, a professor of astronomy at the University of Michigan (UM). “It was shocking to realize that the Milky Way had a large sibling, and we never knew about it.”

The team used computer simulations to determine that most stars in the outermost edges of Andromeda’s “halo” originated from a single location.

“It was a ‘Eureka’ moment,” said study lead author Richard D’Souza. “We realized we could use this information of Andromeda’s outer stellar halo to infer the properties of the largest of these shredded galaxies.”

Additional modeling revealed the likely date of the merger 2 billion years ago and allowed them to reconstruct some details of the ancient galaxy. The team named it M32p, and believe that it was—at minimum—20 times bigger than any galaxy that has ever merged with the Milky Way.

And apparently it’s not completely destroyed either—M32 is likely the galaxy’s corpse.

“M32 is a weirdo,” Bell said. “While it looks like a compact example of an old, elliptical galaxy, it actually has lots of young stars. It’s one of the most compact galaxies in the universe. There isn’t another galaxy like it.”

The findings were published in Nature Astronomy.

A galactic collision influenced history of the Milky Way

According to a team of scientists, the Milky Way evolved about 10 billion years ago when it collided head-on.

As the Milky Way evolved about 10 billion years ago, it collided head-on with another smaller galaxy. That cataclysm changed its structure forever.

Two new studies describe the overlooked evidence for this event. “There’s debris everywhere,” said Vasily Belokurov, an astronomer at the University of Cambridge and a leader of one of the two teams.

To uncover evidence of the collision, astronomers had to sift through multitudinous sources of surviving information. They can use it to compose a story consistent with the available evidence.

Both research teams used information from the European Space Agency’s Gaia space telescope. It has been gathering biographies of millions of stars for several years.

The experiments involved creating high-resolution and multidimensional maps of the Milky Way and using them to find anomalous populations of old stars that seem to retain a memory of the collision. The team found a large number of stars that do not move coordinated with the galaxy’s rotation. Instead, they move in radial orbits, streaming toward or away from the center of the galaxy.

Belokurov’s group also modeled different collision scenarios, as well as a possible quieter history without significant collisions. An impact of a small “dwarf” galaxy could have deposited a cloud of stars like the ones seen today, they discovered.

The collision theory could help resolve a continuing question about the Milky Way’s structure. Its spiral disk of stars is inclusive of two parts: a thin dense region encompassed by a thick diffuse region.