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Deep Sky Observer's Companion – the online database

 

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NGC 4696: A cosmic question mark

NGC 4696, the largest galaxy in the Centaurus Cluster (galaxy cluster Abell 3526), is an elliptical galaxy with a difference.

Elliptical galaxies usually lack the complex structure and star formation of their spiral brethren, appearing as little more than shapeless collections of ageing stars. Such galaxies are most likely formed by collisions between spiral galaxies, and experience a brief burst of star formation triggered as the interstellar dust and gas crash into each other, but which quickly leaves the young elliptical galaxies exhausted. With no more gas to form new stars from, the galaxies gradually grow older and fainter.

But NGC 4696 is more interesting than most elliptical galaxies.

The huge dust lane, around 30 000 light-years across, that sweeps across the face of the galaxy is one way in which it looks different from most other elliptical galaxies. Viewed at certain wavelengths, strange thin filaments of ionized hydrogen are visible within it. In this picture, these structures are visible as a subtle marbling effect across the galaxy’s bright center.

Looking at NGC 4696 in the optical and near-infrared wavelengths seen by Hubble gives a beautiful and dramatic view of the galaxy. But in fact, much of its inner turmoil is still hidden from view in this picture. At the heart of the galaxy, a supermassive black hole is blowing out jets of matter at nearly the speed of light. When looked at in X-ray wavelengths, such as those visible from NASA’s Chandra X-ray Observatory, huge voids within the galaxy become visible, telltale signs of these jets' enormous power.

The picture was created from images taken using the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys. A total of 5440 seconds of exposure through a blue filter (F435W, shown in blue) were combined with 2320 seconds through a near-infrared filter (F814W, shown in red).The field of view is 3.2 by 1.5 arcminutes.

Hubble ESA press release HEIC 1013, 2010 August 12

Recent news

top story: A charming planetary nebula in eastern Triangulum Australe. — A charming planetary nebula in eastern Triangulum Australe.

March newsletter of the ASSA Deep-Sky Section, featuring 47 Tuc on the cover. — "Nightfall" (2015 April) is the current newsletter of the Deep-Sky Observing Section of the Astronomical Society of Southern Africa.

A globular cluster in the realm of the galaxies — A rare gem - a bright globular cluster in the realm of the galaxies.

The Dark Emu rises, in pursuit of the Magellanic Clouds — The beautiful complex of dark nebulosity along the southern Milky Way appears like an ancient monster, its serpentine neck reaching out as if to gobble up the Magellanic Clouds.

Massive star forming region in the Small Magellanic Cloud — Dale Liebenberg images NGC 346, a gigantic star forming region in the SMC.

Flocculent Galaxy in Southern Leo — Dale Liebenberg images the spiral galaxy NGC 3521 in southern Leo.

Ancient open cluster in Lyra — Anthony Ayiomamitis images the old open cluster NGC 6791.

Golden Coin Galaxy — Dale Liebenberg images the Golden Coin, NGC 4945 in Centaurus.

NGC 2467 in Puppis — Dale Liebenberg images NGC 2467 in Puppis.

Last but not least - Messier 103 — Anthony Ayiomamitis images Messier 103 in Cassiopeia.

The Arkenstone of Thrain — Dale Liebenberg images Messier 22, the "Arkenstone of Thrain" according to Burnham.

ConCards available — A handy set of beginner's star charts, "Constellation Cards" are now available for free download.

Deep sky celebrations — Three deep sky observers of yore have birthdays this week: William Herschel (1738), the Fourth Earl of Rosse, and Stephane Javelle.

Necklace Nebula featured on APOD — The recently-discovered planetary nebula nicknamed the Necklace Nebula, recently featured on APOD.

Methuselah Nebula featured on APOD — The old bipolar planetary nebula MWP1, a.k.a. Methuselah Nebula, is today's APOD.

New deepsky book from CUP — Deep sky author Wolfgang Steinicke's latest book, "Observing and Cataloguing Nebulae and Star Clusters: From Herschel to Dreyer's New General Catalogue", has just been published by Cambridge University Press.

NGC 1365 in infrared (ESO VLT) — The bright barred spiral galaxy NGC 1365 in Fornax has been imaged in the infrared with the ESO VLT telescope.

New HST image of eta Carinae Nebula — New observations, combined with images made in 2005, show beautiful detail in part of the extensive eta Carinae Nebula.

First planetary in open cluster found — A team of astronomers from Australia, the UK, the USA and France have discovered the first planetary nebula known to be associated with a galactic open cluster.

NGC 300 in Sculptor imaged at ESO — The bright spiral galaxy NGC 300 has been imaged with the MPG/ESO 2.2-meter telescope at the La Silla Observatory in Chile.

Superwind galaxy NGC 4666 — A remarkable galaxy with very vigorous star formation has been newly imaged on the MPG/ESO 2.2-meter telescope at the La Silla Observatory in Chile.

News archives

All earlier news items can be browsed in the archives.

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(Chinese proverb)

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The Bug Report

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Everything on DOCdb.net is © 2004-2010 by Auke Slotegraaf, unless stated otherwise or if you can prove you have divine permission to use it. Before using material published here, please consult the Creative Commons Attribution-Non-Commercial-Share Alike 2.5 License. Some material on DOCdb is copyright the individual authors. If in doubt, don't reproduce. And that goes for having children, too. Please note that the recommended browser for DOCdb is Firefox 3.x. You may also get good results with K-Meleon. Good luck if you're using IE. A successful experience with other browsers, including Opera and Safari, may vary.