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Post Info TOPIC: Hanny's Voorwerp (SDSS J094103.80+344334.2)
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IC 2497
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A ghostly, glowing, green blob of gas has become one of astronomy's great cosmic mystery stories. The space oddity was spied in 2007 by Dutch high-school teacher Hanny van Arkel while participating in the online Galaxy Zoo project. The cosmic blob, called Hanny's Voorwerp (Hanny's Object in Dutch), appears to be a solitary green island floating near a normal-looking spiral galaxy, called IC 2497. Since the discovery, puzzled astronomers have used a slew of telescopes, including X-ray and radio observatories, to help unwrap the mystery. Astronomers found that Hanny's Voorwerp is the only visible part of a 300-light-year-long gaseous streamer stretching around the galaxy. The greenish Voorwerp is visible because a searchlight beam of light from the galaxy's core illuminated it. This beam came from a quasar, a bright, energetic object that is powered by a black hole. An encounter with another galaxy may have fed the black hole and pulled the gaseous streamer from IC 2497.
Now, with the help of NASA's Hubble Space Telescope, astronomers have uncovered a pocket of young star clusters (colored yellow-orange in the image) at the tip of the green-coloured Hanny's Voorwerp. Hubble also shows that gas flowing from IC 2497 (the pinkish object with the swirling spiral arms) may have instigated the star birth by compressing the gas in Hanny's Voorwerp.
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Blobrana


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RE: Hanny's Voorwerp (SDSS J094103.80+344334.2)
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A strange, glowing green cloud of gas that has mystified astronomers since its discovery in 2007 has been studied by Hubble. The cloud of gas is lit up by the bright light of a nearby quasar, and shows signs of ongoing star formation.
One of the strangest space objects ever seen is being scrutinised by the penetrating vision of the NASA/ESA Hubble Space Telescope. A mysterious, glowing green blob of gas is floating in space near a spiral galaxy. Hubble uncovered delicate filaments of gas and a pocket of young star clusters in the giant object, which is the size of the Milky Way.
The Hubble revelations are the latest finds in an ongoing probe of Hanny's Voorwerp (Hanny's Object in Dutch). It is named after Hanny van Arkel, the Dutch schoolteacher who discovered the ghostly structure in 2007 while participating in the online Galaxy Zoo project. Galaxy Zoo enlists the public to help classify more than a million galaxies catalogued in the Sloan Digital Sky Survey. The project has expanded to include Galaxy Zoo: Hubble, in which the public is asked to assess tens of thousands of galaxies in deep imagery from the Hubble Space Telescope.
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Cosmic Curiosity Reveals Ghostly Glow of Dead Quasar

While sorting through hundreds of galaxy images as part of the Galaxy Zoo citizen science project two years ago, Dutch schoolteacher and volunteer astronomer Hanny van Arkel stumbled upon a strange-looking object that baffled professional astronomers. Two years later, a team led by Yale University researchers has discovered that the unique object represents a snapshot in time that reveals surprising clues about the life cycle of black holes.
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Title: The Sudden Death of the Nearest Quasar
Authors: Kevin Schawinski, Daniel A. Evans, Shanil Virani, C. Megan Urry, William C. Keel, Priyamvada Natarajan, Chris J. Lintott, Anna Manning, Paolo Coppi, Sugata Kaviraj, Steven P. Bamford, Gyula I. G. Józsa, Michael Garrett, Hanny van Arkel, Pamela Gay and Lucy Fortson

Galaxy formation is significantly modulated by energy output from supermassive black holes at the centers of galaxies which grow in highly efficient luminous quasar phases. The timescale on which black holes transition into and out of such phases is, however, unknown. We present the first measurement of the shutdown timescale for an individual quasar using X-ray observations of the nearby galaxy IC 2497, which hosted a luminous quasar no more than 70,000 years ago that is still seen as a light echo in "Hanny's Voorwerp," but whose present-day radiative output is lower by at least two, and more likely by over four, orders of magnitude. This extremely rapid shutdown provides new insight into the physics of accretion in supermassive black holes and may signal a transition of the accretion disk to a radiatively inefficient state.

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Unravelling the mystery of Hanny's Voorwerp

A group of researchers, led by Professor Michael Garrett, General Director of the Netherlands Institute for Radio Astronomy, ASTRON, have made new, high resolution radio observations of the region of space around Hanny's Voorwerp, the mysterious, greenish gas cloud discovered by Dutch school teacher Hanny van Arkel.
The astronomers undertook an observational campaign at radio wavelengths using the European Very Long Baseline Interferometry Network (EVN) and the UK's Multi-Element Radio Linked Interferometer Network (MERLIN), pointing their telescopes at the centre of the neighbouring galaxy IC 2497. In these measurements, several radio telescopes across Europe and the UK were linked together in real-time, in order to gain a detailed picture of the very central region of the galaxy. They observed a field a few arcseconds (the 3600th part of a degree) across, with a spatial resolution of about 70 milliarcseconds (0.07 arcseconds).
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Blobrana


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A University of Alabama astronomer next week will use the Hubble Space Telescope to try and solve a cosmic mystery.
Three years after a Dutch grade school teacher discovered a mysterious object floating in space 600 million light years away, UA's Bill Keel on Monday will point the Hubble at it to try to learn more.
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RE: Hanny's Voorwerp (SDSS J094103.80+344334.2)
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Hanny's Voorwerp in The Sky at Night



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Blobrana


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Eerie Green Space Cloud Explained
An eerie green cloud lurking around a nearby galaxy has puzzled scientists since it was discovered last year. New observations reveal that the cloud's ghoulish appearance may have to do with radiation streaming from a black hole inside the galaxy.

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Blobrana


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Hanny's Voorwerp
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Hanny's voorwerp explained
Hannys voorwerp, a mysterious giant green astronomical object found over a year ago now has a partial explanation, according to a press release from Astron, the Netherlands Institute for Radio Astronomy. It seems that a jet of energetic particles from a nearby black hole has cleared a path in the interstellar medium so that visible and ultraviolet light associated with the black hole can heat the cloud, ionising the particles, and causing it to glow green.

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RE: Hanny's Voorwerp (SDSS J094103.80+344334.2)
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A strange green blob in the nearby universe may be a 'light echo' from a long-dead quasar an extremely bright object powered by a colossal black hole.

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