NGC 3115

Galaxie
NGC 3115
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Aufnahme mithilfe des Hubble-Weltraumteleskops
AladinLite
SternbildSextant
Position
Äquinoktium: J2000.0, Epoche: J2000.0
Rektaszension10h 05m 14,0s[1]
Deklination−07° 43′ 07″[1]
Erscheinungsbild
Morphologischer TypS0- / PAS[1]
Helligkeit (visuell)9,1 mag[2]
Helligkeit (B-Band)10,1 mag[2]
Winkel­ausdehnung7,2′ × 3,2′[2]
Positionswinkel43°[2]
Flächen­helligkeit12,3 mag/arcmin²[2]
Physikalische Daten
ZugehörigkeitNGC 3115-Gruppe[1]
Rotverschiebung0.002287 ± 0.000008[1]
Radial­geschwin­digkeit(686 ± 2) km/s[1]
Hubbledistanz
H0 = 73 km/(s • Mpc)		(23 ± 2) · 106 Lj
(7,05 ± 0,5) Mpc [1]
Durchmesser60.000 Lj[3]
Geschichte
EntdeckungWilhelm Herschel
Entdeckungsdatum22. Februar 1787
Katalogbezeichnungen
NGC 3115 • UGC A 199 • PGC 29265 • MCG -01-26-018 • 2MASX J10051397-0743068 • GC 2008 • H I 163 • h 3223 • USGC S146 NED02 • GIN 775

NGC 3115 ist eine linsenförmige Galaxie vom Hubble-Typ S0 im Sternbild Sextant südlich der Ekliptik. Sie ist schätzungsweise 23 Millionen Lichtjahre von der Milchstraße entfernt und hat einen Durchmesser von etwa 60.000 Lichtjahren. Das Zentrum der Galaxie beherbergt ein extrem massereiches Schwarzes Loch von etwa zwei Milliarden Sonnenmassen, bei einer Gesamtmasse zwischen 300 und 400 Milliarden Sonnenmassen.[4][5]

NGC 3115 wird manchmal auch Spindelgalaxie genannt, nicht zu verwechseln mit der Galaxie Messier 102, die ebenso genannt wird.

Das Objekt wurde am 22. Februar 1787 von dem deutsch-britischen Astronomen Wilhelm Herschel entdeckt.[6]

Überlagerung einer Aufnahme im optischen Spektralbereichs des Very Large Telescope mit einer Aufnahme im Röntgenbereich des Chandra-Weltraumteleskops

Weblinks

Einzelnachweise

  1. ↑ a b c d e NASA/IPAC EXTRAGALACTIC DATABASE
  2. ↑ a b c d e SEDS: NGC 3115
  3. ↑ NASA/IPAC
  4. ↑ Klaus-Peter Schröder, Peter Wienerroither, Daniel Verschatse: Objekte des Monats: NGC-Fischzug südlich des Krebses. In: Sterne und Weltraum. März 2012, S. 78 f.
  5. ↑ K.-P. Schröder, M. Fritz: Objekte des Monats. In: Sterne und Weltraum. März 2015, S. 63.
  6. ↑ Seligman

Auf dieser Seite verwendete Medien

NGC 3115.jpg
The galaxy NGC 3115 is shown here in a composite image of data from NASA's Chandra X-ray Observatory and the European Southern Observatory's Very Large Telescope (VLT). Using the Chandra image, the flow of hot gas toward the supermassive black hole in the center of this galaxy has been imaged. This is the first time that clear evidence for such a flow has been observed in any black hole.

The Chandra data are shown in blue and the optical data from the VLT are colored gold. The point sources in the X-ray image are mostly binary stars containing gas that is being pulled from a star to a stellar-mass black hole or a neutron star. The inset features the central portion of the Chandra image, with the black hole located in the middle. No point source is seen at the position of the black hole, but instead a plateau of X-ray emission coming from both hot gas and the combined X-ray emission from unresolved binary stars is found.

To detect the black hole's effects, astronomers subtracted the X-ray signal from binary stars from that of the hot gas in the galaxy's center. Then, by studying the hot gas at different distances from the black hole, astronomers observed a critical threshold: where the motion of gas first becomes dominated by the supermassive black hole's gravity and falls inwards. The distance from the black hole where this occurs is known as the "Bondi radius."

As gas flows toward a black hole it becomes squeezed, making it hotter and brighter, a signature now confirmed by the X-ray observations. The researchers found the rise in gas temperature begins at about 700 light years from the black hole, giving the location of the Bondi radius. This suggests that the black hole in the center of NGC 3115 has a mass of about two billion times that of the Sun, supporting previous results from optical observations. This would make NGC 3115 the nearest billion-solar-mass black hole to Earth.

NGC 3115 is located about 32 million light years from Earth and is classified as a so-called lenticular galaxy because it contains a disk and a central bulge of stars, but without a detectable spiral pattern.
Caldwell Catalogue.jpg
Autor/Urheber: Roberto Mura, Lizenz: CC BY-SA 3.0
Caldwell Catalogue objects.
Caldwell 53 (50291843072).jpg
Autor/Urheber: NASA Hubble Space Telescope, Lizenz: CC BY 2.0

Lacking spiral arms but boasting a galactic bulge and prominent disk, lenticular galaxies like Caldwell 53 (NGC 3115) are intermediates between the more familiar spiral and elliptical galaxies. This galaxy, like most of its kind, hosts an elderly stellar population and has used up nearly all of its star-forming material. Appearing edge-on to us, the galaxy is located 32 million light-years from Earth in the constellation Sextans and has an apparent magnitude of 9.9. Discovered by William Herschel in 1787, it is most easily observed during early spring in the Northern Hemisphere and autumn in the Southern Hemisphere. As one of the brighter galaxies, Caldwell 53 can be easily seen in a small telescope, which will display the galaxy’s spindle-like form and bright central region.

Caldwell 53 is perhaps most notable for the supermassive black hole that lurks at its center. One of the ways astronomers are able to estimate the mass of a black hole is by observing the temperature of the hot gas being dragged toward it. Using this method, astronomers estimate that the black hole within Caldwell 53 has a mass roughly one billion times the mass of our Sun. This estimation means that Caldwell 53 hosts the closest billion-solar-mass black hole to Earth.

This image of Caldwell 53 is a composite of observations taken by Hubble’s Advanced Camera for Surveys at infrared and visible wavelengths. Scientists used information gathered from these observations to constrain the temperature and density of the gas that surrounds the supermassive black hole at the center of the galaxy.

Credit: NASA, ESA, and J. Erwin (University of Alabama); Processing: Gladys Kober (NASA/Catholic University of America)

For Hubble's Caldwell catalog website and information on how to find these objects in the night sky, visit: <a href="https://www.nasa.gov/content/goddard/hubble-s-caldwell-catalog" rel="noreferrer nofollow">www.nasa.gov/content/goddard/hubble-s-caldwell-catalog</a>