The Dark Energy Survey has now mapped one-eighth of the full sky (red shaded region) using the Dark Energy Camera on the Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile (foreground). This map has led to the discovery of 17 dwarf galaxy candidates in the past six months (red dots), including eight new candidates just announced. Several of the candidates are in close proximity to the two largest dwarf galaxies orbiting the Milky Way, the Large and Small Magellanic Clouds, both of which are visible to the unaided eye. By comparison, the new stellar systems are so faint that they are difficult to “see” even in the deep DES images and can be more easily visualised using maps of the stellar density (inset). Fourteen of the dwarf galaxy candidates found in DES data are visible in this particular image. Illustration credit: Dark Energy Survey Collaboration.

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Smoothed SDSS image of RGG 118, home of the smallest black hole ever observed in a galactic nucleus. The inset shows the Chandra identification of an x-ray source at the center. Credit: Baldassare et al. 2015
A team of astronomers have reported the detection of the smallest black hole (BH) ever observed in a galactic nucleus. The BH is hosted in the center of dwarf galaxy RGG 118, and it weighs in at 50,000 solar masses, according to observations made by Vivienne Baldassare of University of Michigan and her collaborators.

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Alternative gravity theories would result in “bumpy black holes,” which might be identifiable in x-ray observations.

Just before being gobbled up by a black hole, in-falling matter may emit an x-ray signal that could tell us about the black hole’s gravitational field. That’s the assumption of a new theoretical study of matter-accretion disks that form around black holes. The researchers show that alternative gravity models—characterized by “bumps” in the spacetime fabric around the black hole—produce slightly different x-ray emission from the disks. But identifying this signal will be challenging.

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Particle swarm. In Schnittman’s simulation, dark matter particles (shown with gray and pink trails) orbiting a rotating black hole (central sphere) could occasionally gain a large amount of energy and escape. The blue region (the ergosphere) is where the black hole’s rotation pulls spacetime along.

Particles orbiting near a spinning black hole might collide and get ejected with much more energy than previous calculations showed.

Black holes are mostly takers, not givers, but collisions among matter around a spinning black hole can result in high-energy particles that emerge with some of the black hole’s energy. Decades-old calculations showing only a modest energy gain for such particles are now contradicted by new results from two theoretical efforts showing that a particle can take away more than 10 times the energy that was put in. There are still questions about the feasibility of such collisions, but they might help astrophysicists understand some unexplained observations, such as an excess of gamma rays from the galactic center or ultrahigh-energy cosmic rays.

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• A clump of material has been jettisoned from a double star system at incredibly high speeds.
• X-rays from Chandra reveal that a pulsar in orbit around a massive star punched through a circumstellar disk of material.
• Three Chandra observations of the system were taken between December 2011 and February 2014.
• The data suggest the clump may even be accelerating due to the pulsar's powerful winds.

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Einstein Rings are more than just an incredible novelty. It’s also a very rare phenomenon that can offer insights into dark matter, dark energy, the nature of distant galaxies, and the curvature of the Universe itself. The phenomenon, called gravitational lensing, occurs when a massive galaxy in the foreground bends the light rays from a distant galaxy behind it, in much the same way as a magnifying glass would. When both galaxies are perfectly lined up, the light forms a circle, called an “Einstein ring”, around the foreground galaxy. If another more distant galaxy lies precisely on the same sightline, a second, larger ring will appear.

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In 2000, Betsy Weaver got hooked on a vision of things unseen.

As a student at Washington State University, Weaver’s physics program was visited by a group of scientists who lectured on the search into deep, deep, deep outer space. They spoke of phenomena mapped out by Albert Einstein, but so far undetected by humankind. Among these concepts, one stood out: Gravity waves.

Einstein’s math says they exist. Today’s astrophysicists agree. Gravity waves are transmitted from black holes and colliding neutron stars, neither of which has ever “seen” for real. Their existence could open the door to a new way of studying space, beyond optical and radio astronomy, because they can punch through astronomical obstacles that block light, noise and electro-magnetic waves.

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In this short post series I try to tackle one of the biggest questions out there: Are we alone? The reasoning leads to some radical implications for the very near future of humankind. Read till the end and feel free to comment as you go. Hopefully this will spark interesting discussions.

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The LISA Pathfinder spacecraft is due to set off in autumn 2015 in a bid to prove that it is possible to observe gravitational waves in space. This is the latest step in an incredible journey to spot these ripples in spacetime that were first predicted by Albert Einstein 100 years ago.

If we can manage to capture these waves, then we should be able to observe some of the most violent events in the cosmos, such as black holes colliding and galaxies merging.

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Zeuthen, Germany – On 15 and 16 July 2015, the Cherenkov Telescope Array (CTA) Resource Board decided to enter into detailed contract negotiations for hosting CTA on the European Southern Observatory (ESO) Paranal grounds in Chile and at the Instituto de Astrofisica de Canarias (IAC), Roque de los Muchachos Observatory in La Palma, Spain.

The Board, composed of representatives of ministries and funding agencies from Austria, Brazil, the Czech Republic, France, Germany, Italy, Namibia, the Netherlands, Japan, Poland, South Africa, Spain, Switzerland and the UK, decided after months of negotiations and careful consideration of extensive studies of the environmental conditions, simulations of the science performance and assessments of construction and operation costs to start contract negotiations with ESO and Spain. The Namibian and Mexican sites will be kept as viable alternatives.

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Possible layout of the quarks in a pentaquark particle. The five quarks might be tightly bound (left). They might also be assembled into a meson (one quark and one antiquark) and a baryon (three quarks), weakly bound together (Image: Daniel Dominguez)

The LHCb experiment at CERN’s Large Hadron Collider has reported the discovery of a class of particles known as pentaquarks. The collaboration has submitted today a paper reporting these findings (link is external) to the journal Physical Review Letters.

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Five billion years ago, a great disturbance rocked a region near the monster black hole at the center of galaxy 3C 279. On June 14, the pulse of high-energy light produced by this event finally arrived at Earth, setting off detectors aboard NASA's Fermi Gamma-ray Space Telescope and other satellites. Astronomers around the world turned instruments toward the galaxy to observe this brief but record-setting flare in greater detail.

"One day 3C 279 was just one of many active galaxies we see, and the next day it was the brightest thing in the gamma-ray sky," said Sara Cutini, a Fermi Large Area Telescope scientist at the Italian Space Agency's Science Data Center in Rome.

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Some long-duration gamma-ray bursts are driven by magnetars
8 July 2015

Observations from ESO’s La Silla and Paranal Observatories in Chile have for the first time demonstrated a link between a very long-lasting burst of gamma rays and an unusually bright supernova explosion. The results show that the supernova was not driven by radioactive decay, as expected, but was instead powered by the decaying super-strong magnetic fields around an exotic object called a magnetar. The results will appear in the journal Nature on 9 July 2015.

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The film Interstellar should be shown in school science lessons, a scientific journal has urged.
They say their call follows a new insight gained into black holes as a result of producing the visual effects for the Hollywood film.
Experts have also confirmed that the portrayal of "wormholes" is scientifically accurate.
Scientific papers have been published in the American Journal of Physics and in Classical and Quantum Gravity.

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Scientists hope a $200m upgrade to LIGO will bring them nearer to directly observing gravitational waves. (Courtesy: LIGO/Caltech)

A $200m upgrade to the Laser Interferometer Gravitational-wave Observatory (LIGO) has been completed, with the facility set for observations in the coming months as it aims to be the first to detect a gravitational wave. Dubbed Advanced LIGO, it consists of two separate telescopes in the US – the Livingston observatory in Louisiana and the Hanford observatory in Washington state – that use laser interferometers to search for gravitational waves.
According to Einstein's general theory of relativity, gravitational waves are effectively ripples in space–time that travel as a wave. While none have ever been directly detected, scientists have observed a loss of energy as two neutron stars – the dense cores of once-massive stars – spiral toward each other. That energy loss is precisely what Einstein's equations predict would be emitted as gravitational radiation.

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