Gaia discovers its first supernova

Paris (ESA)
Sep 15, 2014

While scanning the sky to measure the positions and movements of stars in our Galaxy, Gaia has discovered its first stellar explosion in another galaxy far, far away.

This powerful event, now named Gaia14aaa, took place in a distant galaxy some 500 million light-years away, and was revealed via a sudden rise in the galaxy's brightness between two Gaia observations separated by one month.

Gaia, which began its scientific work on 25 July, repeatedly scans the entire sky, so that each of the roughly one billion stars in the final catalog will be examined an average of 70 times over the next five years.

"This kind of repeated survey comes in handy for studying the changeable nature of the sky," comments Simon Hodgkin from the Institute of Astronomy in Cambridge, UK.

Many astronomical sources are variable: some exhibit a regular pattern, with a periodically rising and declining brightness, while others may undergo sudden and dramatic changes.

"As Gaia goes back to each patch of the sky over and over, we have a chance to spot thousands of 'guest stars' on the celestial tapestry," notes Dr Hodgkin. "These transient sources can be signposts to some of the most powerful phenomena in the Universe, like this supernova."

Dr Hodgkin is part of Gaia's Science Alert Team, which includes astronomers from the Universities of Cambridge, UK, and Warsaw, Poland, who are combing through the scans in search of unexpected changes.

It did not take long until they found the first 'anomaly' in the form of a sudden spike in the light coming from a distant galaxy, detected on 30 August. The same galaxy appeared much dimmer when Gaia first looked at it just a month before.

"We immediately thought it might be a supernova, but needed more clues to back up our claim," explains Lukasz Wyrzykowski from the Warsaw University Astronomical Observatory, Poland.

Other powerful cosmic events may resemble a supernova in a distant galaxy, such as outbursts caused by the mass-devouring supermassive black hole at the galaxy center.

However, in Gaia14aaa, the position of the bright spot of light was slightly offset from the galaxy's core, suggesting that it was unlikely to be related to a central black hole.

So, the astronomers looked for more information in the light of this new source. Besides recording the position and brightness of stars and galaxies, Gaia also splits their light to create a spectrum. In fact, Gaia uses two prisms spanning red and blue wavelength regions to produce a low-resolution spectrum that allows astronomers to seek signatures of the various chemical elements present in the source of that light.

"In the spectrum of this source, we could already see the presence of iron and other elements that are known to be found in supernovas," says Nadejda Blagorodnova, a PhD student at the Institute of Astronomy in Cambridge.

In addition, the blue part of the spectrum appears significantly brighter than the red part, as expected in a supernova. And not just any supernova: the astronomers already suspected it might be a 'Type Ia' supernova - the explosion of a white dwarf locked in a binary system with a companion star.

While other types of supernovas are the explosive demises of massive stars, several times more massive than the Sun, Type Ia supernovas are the end product of their less massive counterparts.

Low-mass stars, with masses similar to the Sun's, end their lives gently, puffing up their outer layers and leaving behind a compact white dwarf. Their high density means that white dwarfs can exert an intense gravitational pull on a nearby companion star, accreting mass from it until the white dwarf reaches a critical mass that then sparks a violent explosion.

To confirm the nature of this supernova, the astronomers complemented the Gaia data with more observations from the ground, using the Isaac Newton Telescope (INT) and the robotic Liverpool Telescope on La Palma, in the Canary Islands, Spain.

A high-resolution spectrum, obtained on 3 September with the INT, confirmed not only that the explosion corresponds to a Type Ia supernova, but also provided an estimate of its distance. This proved that the supernova happened in the galaxy where it was observed.

"This is the first supernova in what we expect to be a long series of discoveries with Gaia," says Timo Prusti, ESA's Gaia Project Scientist. Supernovas are rare events: only a couple of these explosions happen every century in a typical galaxy. But they are not so rare over the whole sky, if we take into account the hundreds of billions of galaxies that populate the Universe.

Astronomers in the Science Alert Team are currently getting acquainted with the data, testing and optimizing their detection software. In a few months, they expect Gaia to discover about three new supernovas every day.

In addition to supernovas, Gaia will discover thousands of transient sources of other kinds - stellar explosions on smaller scale than supernovas, flares from young stars coming to life, outbursts caused by black holes that disrupt and devour a nearby star, and possibly some entirely new phenomena never seen before.

"The sky is ablaze with peculiar sources of light, and we are looking forward to probing plenty of those with Gaia in the coming years," concludes Dr Prusti.

Source: Skynightly.
Link: http://www.skynightly.com/reports/Gaia_discovers_its_first_supernova_999.html.

Iran president pledges to back Iraq amid attacks

October 21, 2014

TEHRAN, Iran (AP) — Iranian President Hassan Rouhani promised on Tuesday that Iran will stand by Iraq in the neighboring country's fight against the Sunni extremists of the Islamic State group.

Rouhani told visiting Iraqi Prime Minister Heidar al-Abadi that Iran "will remain on the path until the last day," according to a report by the official IRNA news agency. Rouhani says Iran will continue to provide Baghdad with military advisers and weapons. He also criticized the U.S. for allegedly failing to sufficiently support Iraq against an escalating Sunni insurgency.

That insurgency continued its wave of attacks on Tuesday as a string of bombings in and near Baghdad killed 26 people. Police officials said the deadliest attack took place Tuesday afternoon when a double car bomb attack hit Habaybina restaurant in the Shiite-majority district of Talibiya in eastern Baghdad, killing 15 people and wounding 32 others.

Earlier, a bomb struck at an outdoor market in the southern district of Abu Dashir, a mostly Shiite neighborhood, killing four people and wounding nine, police officials said. A little bit later, a bomb that went off near a small restaurant in central Baghdad killed five people and wounded 12, the officials said. Another bomb exploded at a commercial street in the town of Madian, just south of Baghdad, killing two people and wounding four.

Medical officials confirmed the casualty figures. All officials spoke on condition of anonymity because they were not authorized to talk to media. No one immediately claimed responsibility for the latest attacks but they bore the hallmarks of the al-Qaida-breakaway Islamic State group which has captured large chunks of territory in western and northern Iraq, plunging the country into its worst crisis since U.S. troops left at the end of 2011.

On Monday, militants unleashed a wave of deadly attacks on Iraq's majority Shiite community, killing at least 43 people. In the Shiite holy city of Karbala — home to the tombs of two revered Shiite imams and the site of year-round pilgrimages — four separate car bombs went off simultaneously, killing at least 26 people.

The attacks on the Shiites are likely calculated by the Sunni extremists to sow fear among Iraqis on both sides of the sectarian divide.

Yacoub reported from Baghdad. Associated Press writer Murtada Faraj in Baghdad contributed to this report.

Head of Iran's chief clerical body dead at 83

October 21, 2014

TEHRAN, Iran (AP) — A leading Iranian cleric, Ayatollah Mohammadreza Mahdavi Kani, who headed the country's most influential clerical body charged with choosing or dismissing the nation's supreme leader, has died. He was 83.

Kani was the chairman of the Assembly of Experts, a body of 86 senior clerics that monitors the supreme leader and picks a successor after his death. That makes it potentially one of the most powerful institutions in Iran, although it does not involve itself the daily affairs of state.

Iran's President Hassan Rouhani declared two days of national mourning. Kani held the top post at the Assembly of Experts since March 2011, after his predecessor, Iran's influential former President Akbar Hashemi Rafsanjani was forced out following a dispute with hard-line clerics who backed then-President Mahmoud Ahmadinejad.

Kani also served as acting prime minister and interior minister in the 80s. He had been in a coma since June, after being hospitalized for heart failure. Kani was considered a moderate conservative and had backed Rouhani in his bid for the presidency in 2013.

The Assembly of Experts has only once picked a supreme leader since the 1979 Islamic Revolution — in 1989, when it chose Ayatollah Ali Khamenei to succeed his late mentor, the Islamic Revolution patriarch Ayatollah Ruhollah Khomeini.

Khani's family said he will be buried on Thursday.

Iran military ready to ship equipment to Lebanon

October 20, 2014

TEHRAN, Iran (AP) — Iran's defense minister said his country is ready to ship defensive materials to Lebanon to aid its army in the fight against Sunni extremists on Monday, the semi-official Mehr news agency reported.

The report quoted Gen. Hossein Dehghan, speaking at a joint briefing with visiting Lebanese Defense Minister Samir Moqbel, as saying the shipment would help thwart extremists who plan to commit "inhuman crimes" in Syria, Iraq and Lebanon.

"We will provide an Iranian-made consignment of defensive items to the Lebanese army for their use in fighting the group and other terrorist groups," Dehghan said. The Lebanese troops have been fighting militants from the Islamic State group since fighting spilled into the Mediterranean country from neighboring Syria.

Dehghan did not elaborate on the contents of the shipment but said it was a gift intended for "swift action against a possible threat." The United Nations imposed an arms embargo on Iran in 2007, banning it from importing and exporting weapons.

"The aid mainly includes items for ground forces — for confronting terrorist currents," he said, adding that Iran was also ready to provide training to the Lebanese army. The shipment now awaits approval from Lebanon, Dehghan said, a country he described as having a "special position" in Iran's foreign policy. Shiite Iran backs Lebanon's Hezbollah, a Shiite militant group now fighting alongside forces of key Iran ally President Bashar Assad against the Sunni extremists in Syria.

Iran's former ambassador to Beirut, Ghazanfar Roknabadi, said the U.S. and some groups in Lebanon are worried about the aid because they are concerned it could be used against Israel. "They say the aid breaks sanctions, but it is just a gift and there is no money in return," said Roknabadi, adding that Iran had proposed gifting the aid years ago.

Iran, a major weapons manufacturer in the region, has in the past said it exported military products to scores of countries, although it has never revealed details.

China completes construction of advanced space launch facility

Beijing (SPX)
Sep 12, 2014

China has finished building of its fourth and most advanced space launch center, a senior space official said.

Yang Liwei, deputy director of the China Manned Space Agency, said in Beijing on Wednesday that infrastructure construction on the Wenchang Satellite Launch Center in the southern island province of Hainan has been completed and that the station will soon become operational.

"The center is basically ready for spacecraft launches," he said.

Yang also said the nation's space program is progressing in the development of the Tiangong-2 space lab, the Tianzhou cargo spacecraft, the Shenzhou-11 manned spacecraft and the Long March 2F-Y11 rocket as astronauts and ground facilities begin preparing for new missions.

After Tiangong-2 is launched around 2016, Shenzhou-11 and Tianzhou will be sent into space to dock with it, he said.

China has three operational space launch centers in Sichuan and Shanxi provinces and the Inner Mongolia autonomous region.

According to earlier reports, more than 6,000 people would be relocated to make way for the Wenchang center. The construction of the center was approved by the State Council and the Central Military Commission in 2007, and work began in 2009.

The biggest advantage of the Wenchang center is its low latitude - 19 degrees north of the equator - which will enable rockets to save a lot of fuel compared with launches from other centers in China, experts said.

A satellite launched from Wenchang is expected to have a longer service life as a result of the fuel saved by the shorter trip from transit orbit to geosynchronous orbit.

The favorable location also allows a substantial increase in payload on the rockets to allow them to carry heavier spacecraft.

Liu Jianzhong, deputy designer of the Long March-5 rocket system, China's most powerful rocket that is under development, said the new center would be suitable for the launch of the Long March-5 because the large rocket can be transported to the center by sea.

Other launch centers in China are in inland regions and have to transport their rockets by rail.

"Launching from the Wenchang facility also means rocket wreckage will fall into the sea rather than onto inhabited areas," he said.

Source: Space Daily.
Link: http://www.spacedaily.com/reports/China_completes_construction_of_advanced_space_launch_facility_999.html.

SpaceX's next cargo launch set for Sept 20

Washington (AFP)
Sept 12, 2014

SpaceX's next unmanned cargo trip to restock supplies at the International Space Station is scheduled for September 20, the US space agency said Friday.

The Dragon spacecraft will launch atop a Falcon 9 rocket at 2:16 am (0616 GMT) on September 20 from Cape Canaveral Air Force Station in Florida, NASA said.

"If for any reason the launch is postponed, the next launch opportunity is Sunday, Sept. 21 at approximately 1:53 am," it said in a statement.

The cargo ship will be loaded with more than 5,000 pounds (2,300 kilograms) of supplies and scientific experiments, including an ocean surface wind speed monitor, equipment for studying rodents in microgravity and cabbage-like plants to see how their growth adapts in space.

The mission, called SpaceX CRS-4, "is the fourth of 12 SpaceX flights NASA contracted with the company to resupply the space station," the space agency said.

The trip marks the fifth Dragon journey to the orbiting outpost, including its initial demonstration mission.

SpaceX and Orbital Sciences Corporation each have billion-dollar contracts with NASA to supply the space station over the coming years.

The retirement of the space shuttle program in 2011 has left the United States without a government spacecraft to transport cargo or crew to the space station.

Source: Space-Travel.
Link: http://www.space-travel.com/reports/SpaceXs_next_cargo_launch_set_for_Sept_20_999.html.

Japan space agency unveils asteroid hunting probe

Tokyo (AFP)
Sept 02, 2014

Japanese space scientists have unveiled the asteroid hunting space probe they hope to launch later this year on a mission to mine a celestial body.

The probe, named Hayabusa-2, is expected to be flung into space on a rocket for a mammoth four year voyage to the unpoetically-named 1999JU3 asteroid.

When it gets there, some time in 2018, it will release a powerful cannon which will fire a metal bullet at the asteroid's barren crust, once the probe itself has scuttled to safety on the far side of the rock.

It will then return to scoop up material uncovered by the cannon blast.

If all goes well, these pristine asteroid samples will be returned to Earth by the time Tokyo hosts the Olympic Games in 2020.

At a weekend press conference, Hitoshi Kuninaka, project leader at the Japan Aerospace Exploration Agency (JAXA) said he and his team were readying to redouble their efforts for this "new voyage".

"I'm grateful as the new asteroid probe is now nearly complete," he said, according to Jiji Press.

The probe is the successor to JAXA's first asteroid explorer, Hayabusa -- the Japanese term for falcon -- which returned to earth in 2010 with dust samples after a trouble-plagued seven-year mission.

The spherical 1999JU3 asteroid, which is around a kilometer (half a mile) across, contains significantly more organic matter and water than the potato-shaped rock previously studied by the original Hayabusa.

Analyzing this valuable cosmic material could shed light on the mysteries surrounding the solar system and its origins 4.6 billion years ago.

Scientists at JAXA say Hayabusa-2 will build on the work of its predecessor, which was only able to collect surface dust samples that could have been altered by years of exposure to various forms of energy encountered in space.

Despite various setbacks during its epic seven-year journey, including intermittent loss of communication and damage to its motors, the first Hayabasa was hailed as a triumph of science when it returned to Earth.

JAXA's work guiding the craft back to terra firma made it a source of pride for Japan, even inspiring several Japanese feature films.

Kuninaka said there were a number of possible complications and pitfalls that could await Hayabusa-2.

"Of course, I hope things will go smoothly," said Kuninaka.

"We have had many difficulties in the process of developing the new asteroid probe. Space is never an easy place," he said.

Asteroids are believed to retain materials unchanged from the solar system's earliest days, unlike scorched remains such as meteorites or materials on Earth which have been transformed through pressure and heat.

The 1999JU3 asteroid was selected in part because of its make-up and also because of its relative accessibility.

Source: Space Daily.
Link: http://www.spacedaily.com/reports/Japan_space_agency_unveils_asteroid_hunting_probe_999.html.