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Archive for March 5, 2014

The shadows Of Petra Awaken Its Astronomical Orientation


Credit: J. A. Belmonte - A. C. González-García

Credit: J. A. Belmonte – A. C. González-García

During the winter solstice, the sun is filtered into the Monastery at Petra, Jordan, illuminating the podium of a deity. Just at this moment, the silhouette of the mountain opposite draws the head of a lion, a sacred animal. These are examples from a study where researchers from Instituto de Astrofisica de Canarias and CSIC (Spain) showed how celestial events influenced the orientation of the great constructions of the Nabataeans.

The movement of the Sun in the skies of Petra determined the way in which the monuments of this and other Natabean cities were erected. This is according to a statistical analysis on the spatial position of their palaces, temples and tombs carried out by scientists from Instituto de Astrofisica de Canarias (IAC) and CSIC, Spain, and the University of Perugia (Italy).

The results, published by the ‘Nexus Network Journal’, indicate that those great buildings were erected bearing in mind the equinoxes, solstices and other astronomical events that determined the Nabataean religion. The Nabataeans prospered in the first century BC and the first century AD in what is now Jordan and neighbouring countries.

“The Nabataean monuments are marvellous laboratories where landscape features and the events of the sun, moon and other stars interact,” Juan Antonio Belmonte, researcher of IAC and coordinator of the study, stressed to SINC.

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RX J1131-1231: Chandra & XMM-Newton Provide Direct Measurement Of Distant Black Hole’s Spin


Credit: X-ray: NASA/CXC/Univ of Michigan/R.C.Reis et al; Optical: NASA/STScI

Credit: X-ray: NASA/CXC/Univ of Michigan/R.C.Reis et al; Optical: NASA/STScI

Multiple images of a distant quasar are visible in this combined view from NASA’s Chandra X-ray Observatory and the Hubble Space Telescope. The Chandra data, along with data from ESA’s XMM-Newton, were used to directly measure the spin of the supermassive black hole powering this quasar. This is the most distant black hole where such a measurement has been made, as reported in our press release.

Gravitational lensing by an intervening elliptical galaxy has created four different images of the quasar, shown by the Chandra data in pink. Such lensing, first predicted by Einstein, offers a rare opportunity to study regions close to the black hole in distant quasars, by acting as a natural telescope and magnifying the light from these sources. The Hubble data in red, green and blue shows the elliptical galaxy in the middle of the image, along with other galaxies in the field.

The quasar is known as RX J1131-1231 (RX J1131 for short), located about 6 billion light years from Earth. Using the gravitational lens, a high quality X-ray spectrum – that is, the amount of X-rays seen at different energies – of RX J1131 was obtained.

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