X-ray nova discovered by MAXI

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www.jaxa.jp : Discovery of an X-ray Nova by the Monitor of All-sky X-ray Image (MAXI)
September 29, 2010 (JST)

Japan Aerospace Exploration Agency (JAXA)
Institute of Physical and Chemical Research (RIKEN)

The Monitor of All-sky X-ray Image (MAXI) mission team discovered an X-ray nova by MAXI's X-ray cameras, which are working on the Exposed Facility of the Japanese Experiment Module "KIBO" of the International Space Station. The team immediately reported their discovery to the world.
This X-ray nova emerged in the constellation of Ophiuchus, and the MAXI nova alert system detected its emergence at around 7:00 p.m. on September 25, 2010 (Japan Standard Time, all the following dates and times are JST.) The discovery was immediately notified to all researchers registered on the MAXI mailing list, and with their detailed analysis the MAXI team confirmed that it is an uncatalogued X-ray source. The nova was named "MAXI J1659-152," and the discovery was reported to the world through the Astronomer's Telegram, ATel, at around 1:00 a.m. on September 26.

Change of X-ray Strength over time when the nova was discovered.

The X-ray strength drastically increased on Sept. 25. At around 7:00 p.m. on Sept. 25,
the MAXI nova alert system captured this increase.

Following the discovery, many astronomical observatories around the world have started observing this nova in X-ray, gamma-ray, visible, infrared, and radio wavelengths. As of 0:00 a.m. on Sept. 29, seventeen reports have been issued on this matter. Astronomers across the world are paying attention to this nova as it is likely to be a binary system with a black hole. The Japanese X-ray Astronomy Satellite "Suzaku" is also conducting detailed observations.
This discovery was led by Prof. Hitoshi Nego, a member of the MAXI team.

Comparison of all-sky images before and after Sept. 25 when the nova was found

Mission website:

http://kibo.jaxa.jp/en/experiment/ef/maxi/ (MAXI mission site)
http://iss.jaxa.jp/ (International Space Station/Kibo Information Center)
http://maxi.riken.jp/top/ (Riken MAXI site)


http://www.jaxa.jp : Discovery of New X-ray Celestial Body in Centaurs
by Monitor of All-sky X-ray Image (MAXI)

October 22, 2010 (JST)

Japan Aerospace Exploration Agency (JAXA)
Institute of Physical and Chemical Research (RIKEN)

The MAXI Mission Team found a new X-ray celestial body by the Monitor of All-sky X-ray Image (MAXI) installed on the Exposed Facility of the Japanese Experiment Module "Kibo" on October 17 (Sun.) This is the second nova discovery by the MAXI following the finding of MAXI J1659-152 on September 25 (Sat.).
The nova emerged in Centaurs became brighter around October 17, but, as it was still dark, we took a few days to analyze observation data, then reported its location information to the world at around 8:00 p.m. on Oct. 20 (Wed., Japan Standard Time) through the Astronomer's Telegram (ATel No.2959.) Upon receiving this report, NASA's astronomical satellite "Swift" (*1) conducted an urgent tracking and observation from midnight October 21 (JST.) As a result, the nova was confirmed to be a unprecedented bright X-ray source. It is predicted to be highly possible that the nova is either a neutron star with a companion star of a massive star which exists extremely far away, over several ten thousands light-years, in the Galaxy, or a black hole.
With the discovery this time, the MAXI proved its capability of discovering a X-ray nova existing far away in the Galaxy. The MAXI team will continue its observations in cooperation with the Swift satellite to elucidate more details of this nova. It is named "MAXI J1409-619."

*1 Gamma-ray burst observation satellite launched on Nov. 20, 2004.


http://www.science.psu.edu : Japanese and U.S. Space Telescopes Reveal Previously Unknown Brilliant X-Ray Explosion in Our Milky Way Galaxy
22 October 2010

Images of areas of 10 degrees in radius around the nova MAXI J1409-619. A celestial body that was not observed on Oct. 12 shone bright on the 17th. Credit: JAXA/RIKEN/MAXI team.

— Astronomers in Japan, using an X-ray detector on the International Space Station, and at Penn State University, using NASA's Swift space observatory, are announcing the discovery of an object newly emitting X-rays, which previously had been hidden inside our Milky Way galaxy in the constellation Centaurus.

The object -- a binary system -- was revealed recently when an instrument on the International Space Station named MAXI (Monitor of All-Sky X-ray Image) on the Exposed Facility of the Japanese Experiment Module "Kibo" caught it in the act of erupting with a massive blast of X-rays known as an X-ray nova. The MAXI mission team quickly alerted astronomers worldwide to the discovery of the new X-ray source at 2:00 a.m. EDT on Wednesday, 20 October, and NASA's Swift Observatory quickly conducted an urgent "target-of-opportunity" observation nine hours later, which allowed for the location of the X-ray nova to be measured accurately.

"The collaboration between the MAXI and Swift teams allowed us to quickly and accurately identify this new object," said Jamie Kennea, the Swift X-ray Telescope instrument scientist at Penn State University who is leading the Swift analysis. "MAXI and Swift's abilities are uniquely complementary, and in this case have provided a discovery that would not have been possible without combining the knowledge obtained from both."

The detailed X-ray image shot by the Swift satellite. An unknown bright new celestial body was seen in the brighter part (0.2 degrees in radius) observed by the MAXI. Credit: MAXI/Swift team

The Swift detection confirmed the presence of the previously unknown bright X-ray source, which was named MAXI J1409-619. "The Swift observation suggests that this source is probably a neutron star or a black hole with a massive companion star located at a distance of a few tens of thousands of light years from Earth in the Milky Way," said David Burrows, professor of astronomy and astrophysics at Penn State and the lead scientist for Swift's X-ray Telescope. "The contribution of Swift's X-ray Telescope to this discovery is that it can swing into position rapidly to focus on a particular point in the sky and it can image the sky with high sensitivity and high spatial resolution."

"MAXI has demonstrated its capability to discover X-ray novae at great distances," said Kazutaka Yamaoka, assistant professor at Aoyama Gakuin University and a member of the MAXI team. "The MAXI team is planning further coordinated observations with NASA satellites to reveal the identity of this source."
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