xmm newton

(Image)  NGC 5907 X-1: record-breaking pulsar

(ESA)  The Brightest, Furthest Pulsar In the Universe

ESA’s XMM-Newton has found a pulsar – the spinning remains of a once-massive star – that is a thousand times brighter than previously thought possible.

The pulsar is also the most distant of its kind ever detected, with its light travelling 50 million light-years before being detected by XMM-Newton.

Pulsars are spinning, magnetised neutron stars that sweep regular pulses of radiation in two symmetrical beams across the cosmos. If suitably aligned with Earth these beams are like a lighthouse beacon appearing to flash on and off as it rotates. They were once massive stars that exploded as a powerful supernova at the end of their natural life, before becoming small and extraordinarily dense stellar corpses.

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Brightest neutron star yet has a multipolar magnetic field

Scientists have identified a neutron star that is consuming material so fast it emits more x-rays than any other.

Its extreme brightness can only be explained if the star has a complex multipolar magnetic field, the researchers say.

Ultraluminous x-ray sources (ULXs) are seen in some nearby galaxies and shine brighter than any x-ray source in our own galaxy.

Simple calculations show that, for such an intense amount of energy to be emitted, ULXs should be powered by black holes accreting surrounding material.

Here, using the X-ray Multi-Mirror Mission (XMM-Newton) and Nuclear Spectroscopic Telescope Array (NuSTAR) space telescopes, Gian Luca Israel and colleagues detected periodic signals in x-rays emitted by a ULX in the nearby spiral galaxy NGC 5907, indicating that it is instead powered by a spinning neutron star.

The star, known as NGC 5907 ULX, is accreting material so fast that its spin period is accelerating at astounding rates - it evolved from 1.43 seconds in 2003 to 1.13 seconds in 2014.

Its peak luminosity exceeds the Eddington limit, the theoretical maximum set by the balance between the force of radiation acting outward and the gravitational force acting inward, by roughly 1,000 times what would be expected for a neutron star.

The authors say that the only way to explain the data is if the neutron star does not have a simple (dipolar) magnetic field.

Modelling shows that a strong, multipolar magnetic field could explain the extreme properties of NGC 5907 ULX and how it exceeds the Eddington limit.

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Record-Breaking Galaxy Cluster Confirms Dark Matter Universe

“But this new cluster is just 2.6 billion years old, and seems to be undergoing the very transition where a collection of galaxies falls into a bound structure for the first time, from a protocluster to a true galaxy cluster. This marks the first time astronomers have ever detected such an event: of the exact moment that a protocluster transitions to a true cluster. The fact that so many total galaxies (seventeen!) were discovered localized together at the same redshift (z=2.506) was a big hint, but the final piece of evidence came from the X-rays, where the diffuse emission engulfing the entire set of objects shows, beyond a shadow of a doubt, that this really is a galaxy cluster!”

There was once a time early on in the Universe where there were no stars, no galaxies and no clusters of galaxies at all. While stars and galaxies form very early on, after only tens or hundreds of millions of years, it takes billions of years for the first clusters to form. Yet even if we were to look back into the Universe’s past up to ten billion years, the clusters we see are already well-evolved and quiet. We had never seen a set of galaxies fall in and actively form a cluster before. We’d never seen the protocluster/cluster transition before. And we’d never found one from when the Universe was between two and three billion years old: when our dark matter theory predicts the first great clusters ought to form. Until, that is, now.

Come see how the Chandra X-ray observatory just found a record-breaking cluster that confirms our greatest picture of the Universe’s history!

En ilginç yıldızlardan bazıları özel, gizli bölgelerde yaşarlar. Cygnus OB2 olarak bilinen yıldızlar grubu, içlerinden yaklaşık 100 tanesi bilinen normal yıldızların en devasa ve ekstrem olanları olan 3000 yıldızın birlikteliğinde de durum böyledir. Astronomlar bu nadir dev yıldızlar üzerine çalışmakta oldukça istekliler, ancak ne yazık ki Cyg OB2, en azından Dünya’dan görüldüğü kadarıyla Galaksi’nin nispeten kirli, araya giren dev toz bulutlarının önemli bilgileri astronomların gözlerinden sakladığı bir bölgesinde yaşıyor. Ama bu yıldızlardan pek çoğu X-ışın kaynakları ve X-ışınları çok büyük miktarlarda toz ve diğer yıkıntıyı delip geçebilir ve saklı kalmış önemli fiziksel detayları açığa çıkarır. Bu bölgenin özel bir sakini, Cyg OB2 #9 olarak bilinen bir yıldız X-ışını yayınladığı keşfedilen ilk dev yıldızlardan biri. Cyg OB2 #9’un X-ışını yayınlama sebebi 30 yıldan uzun süre boyunca bir gizemdi. Şimdilerde #Swift ve #XMM-Newton gibi X-ışın uydu gözlemevlerinden bir filo ve yer temelli radyo teleskoplar kullanan astronomlar bu gizemi çözdüler. Ortaya çıktı ki Cygnus OB2 #9 ikili bir yaşam sürüyor – tek bir yıldız değil, dev bir yoldaş yıldıza sahip bir çift sistemi. Her iki yıldız da kuvvetli yıldız rüzgarlarına sahip ve iki yıldız dış merkezli, 660 günlük yörüngelerinde dans ettikçe bu rüzgarlar çarpışıyorlar. Bu şiddetli çarpışma milyonlarca derecelik sıcaklıklarda, X-ışın emisyonu üretmeye yetecek kadar sıcak gaz meydana getiriyor. Yalnızca bu kadar da değil, yıldızlar birbirlerinin etrafında döndükçe bu X-ışın emisyonu anlaşılabilir şekilde değişiyor. Şimdi astronomlar, yeni gözlemler sağ olsun, bu sistemi kısmen detaylı olarak modellemeyi başardılar. Cyg OB #9’un yıldız bileşenleri arasındaki rüzgar çarpışmasının daha hafif olan yıldızın çevresindeki bir yay şok dalgasını gösteren bilgisayar simülasyonu yukarıda gösteriliyor.⠀

Görsel/Referans: Australian National Univ./E. R. Parkin ve Univ. of Lige/E. Gosset⠀

#heasarc #heapow #uzay #bilim #astronomi #astrofizik #uzaydanhaberler #science #space #astronomy #astrophysics

BLACK HOLE MEAL SETS RECORD FOR DURATION AND SIZE

A giant black hole ripped apart a star and then gorged on its remains for about a decade, according to astronomers. This is more than 10 times longer than any observed episode of a star’s death by black hole.

Researchers made this discovery using data from NASA’s Chandra X-ray Observatory and Swift satellite as well as ESA’s XMM-Newton.

The trio of orbiting X-ray telescopes found evidence for a “tidal disruption event” (TDE), wherein the tidal forces due to the intense gravity from a black hole can destroy an object – such as a star – that wanders too close. During a TDE, some of the stellar debris is flung outward at high speeds, while the rest falls toward the black hole. As it travels inwards to be ingested by the black hole, the material becomes heats up to millions of degrees and generates a distinct X-ray flare.

“We have witnessed a star’s spectacular and prolonged demise,” said Dacheng Lin from the University of New Hampshire in Durham, New Hampshire, who led the study. “Dozens of tidal disruption events have been detected since the 1990s, but none that remained bright for nearly as long as this one.”

The extraordinary long bright phase of this event spanning over 10 years means that among observed TDEs this was either the most massive star ever to be completely torn apart during one of these events, or the first where a smaller star was completely torn apart.

The X-ray source containing this force-fed black hole, known by its abbreviated name of XJ1500+0154, is located in a small galaxy about 1.8 billion light-years from Earth.

The source was not detected in a Chandra observation on April 2, 2005, but was detected in an XMM-Newton observation on July 23, 2005, and reached peak brightness in a Chandra observation on June 5, 2008. These observations show that the source became at least 100 times brighter in X-rays. Since then, Chandra, Swift, and XMM-Newton have observed it multiple times.

The sharp X-ray vision of Chandra data shows that XJ1500+0154 is located at the center of its host galaxy, the expected location for a supermassive black hole.

The X-ray data also indicate that radiation from material surrounding this black hole has consistently surpassed the so-called Eddington limit, defined by a balance between the outward pressure of radiation from the hot gas and the inward pull of the gravity of the black hole.

“For most of the time we’ve been looking at this object, it has been growing rapidly,” said co-author James Guillochon of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. “This tells us something unusual – like a star twice as heavy as our Sun – is being fed into the black hole.”

The conclusion that supermassive black holes can grow, from TDEs and perhaps other means, at rates above those corresponding to the Eddington limit has important implications. Such rapid growth may help explain how supermassive black holes were able to reach masses about a billion times higher than the Sun when the universe was only about a billion years old.

“This event shows that black holes really can grow at extraordinarily high rates,” said co-author Stefanie Komossa of QianNan Normal University for Nationalities in Duyun City, China. “This may help understand how precocious black holes came to be.”

Based on the modeling by the researchers the black hole’s feeding supply should be significantly reduced in the next decade. This would result in XJ1500+0154 fading in X-ray brightness over the next several years.

(NASA)  Supernova Remnant Puppis A
Image Credit: X-ray: NASA/CXC/IAFE/ G. Dubner et al., ESA/XMM-Newton
Infrared: NASA/ESA/JPL-Caltech/GSFC/ R. Arendt et al.

Driven by the explosion of a massive star, supernova remnant Puppis A is blasting into the surrounding interstellar medium about 7,000 light-years away. At that distance, this remarkable false-color exploration of its complex expansion is about 180 light-years wide. It is based on the most complete X-ray data set so far from the Chandra and XMM/Newton observations, and infrared data from the Spitzer Space Telescope. In blue hues, the filamentary X-ray glow is from gas heated by the supernova’s shock wave, while the infrared emission shown in red and green is from warm dust. The bright pastel tones trace the regions where shocked gas and warmed dust mingle. Light from the initial supernova itself, triggered by the collapse of the massive star’s core, would have reached Earth about 3,700 years ago, though the Puppis A supernova remnant remains a strong source in the X-ray sky.

Hallan la primera estrella de neutrones de Andrómeda

Se encuentra a 2.537.000 años luz de la Tierra y junto con la Vía Láctea y la Galaxia del Triángulo, conforman las tres grandes galaxias espirales del Grupo Local. Ahora, tras décadas de búsqueda, un equipo de astrofísicos ha descubierto un objeto difícil de localizar en el universo: una estrella de neutrones. Este cadáver (o remanente) estelar ha sido localizado gracias al telescopio espacial XMM-Newton de la ESA.

La galaxia de Andrómeda es muy popular entre los astrónomos ya que es el objeto visible a simple vista más lejano de la Tierra y el más parecido a la Vía Láctea, lo que la convierten en un interesante laboratorio natural para los científicos. Durante décadas los telescopios han examinado al detalle todo el espectro electromagnético pero, hasta ahora, nunca había podido localizarse una estrella de neutrones.

Las estrellas de neutrones giran tan rápidamente que pueden incluso barrer pulsos regulares de radiación hacia la Tierra, como si de un faro cósmico se tratara, que puede “encenderse” y “apagarse” a medida que gira. Si “canibalizan” a alguna estrella vecina, la estrella de neutrones gira aún más rápido.

Los datos del telescopio de rayos X permitieron localizar la señal de una fuente inusual de una estrella de neutrones con un giro extremadamente rápido. Según los expertos, parece estar alimentándose de una estrella vecina que orbita cada 1,3 días, lo que le hace girar cada 1,2 segundos. Sin duda es inusual y exótica.

“Estábamos esperando detectar señales periódicas entre los objetos más brillantes de rayos X en Andrómeda, pero púlsares de rayos X brillantes tan persistentes como este siguen siendo un tanto peculiares. Buscamos a través de los datos de archivo de Andrómeda que abarca 2000-13, pero no fue hasta 2015 que finalmente fuimos capaces de identificar este objeto en la espiral exterior de la galaxia en sólo dos de las 35 mediciones”, explica Gian Luca Israel, coautor del estudio.

“Podría ser lo que llamamos un púlsar peculiar de rayos X de baja masa, pero necesitamos adquirir más observaciones del púlsar y su compañera para ayudar a determinar cuál es el escenario más probable”, comenta Paolo Esposito, coautor del trabajo.

El hallazgo ha sido publicado en la revista Monthly Notices of the Royal Astronomical Society.

This artist’s conception shows how supermassive black holes at the cores of galaxies blast radiation and ultra-fast winds outward. New data from NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) and the European Space Agency’s (ESA’s) XMM-Newton telescopes show that these winds, containing gases of highly ionized atoms, blow in a nearly spherical fashion, emanating in every direction, as shown in the artwork. 

With the shape and extent of the winds known, the researchers were able to determine the winds’ strength. The high-speed winds are powerful enough to shut down star formation throughout a galaxy.

The artwork is based on an image of the Pinwheel galaxy (Messier 101) taken by the Hubble Space Telescope.

A Precocious Black Hole

In July 2015, researchers announced the discovery of a black hole that grew much more quickly than its host galaxy. The discovery calls into question previous assumptions on development of galaxies. The black hole was discovered using the Hubble Space Telescope, and detected in the Sloan Digital Sky Survey, by ESA’s XMM-Newton and NASA’s Chandra.