NGC 1399

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NGC 1399
NGC 1399 HST 10911 R814GB475.png
Hubble Space Telescope image of NGC 1399
Observation data (J2000 epoch)
Constellation Fornax
Right ascension 03h 38.5m [1]
Declination −35° 27′ [1]
Distance 20.23 Mpc (66 Mly)
Apparent magnitude  (V)9.9 [1]
Characteristics
Type E1p [1]
Apparent size  (V)3.2′ × 3.1′ [1]
Notable featuresCentral galaxy of the Fornax cluster
Other designations
6dFGS gJ033829.0-352702, 2E 816, 2E 0336.5-3536, ESO 358-45, ESO-LV 358-0450, FCC 213, 1H 0335-357, H 0333-35, LEDA 13418, 2MASX J03382908-3527026, MCG-06-09-012, MSH 03-3-03, OHIO E -361, PKS 0336-35, PKS 0336-355 PKS J0338-3523, RBS 454, 1RXS J033828.8-352701, SGC 033634-3536.7, [CAC2009] S0373 b, [CHM2007] HDC 234 J033829.08-3527026, [CHM2007] LDC 249 J033829.08-3527026, [DLB87] F5, [FWB89] Galaxy 100

NGC 1399 is a large elliptical galaxy in the Southern constellation Fornax, the central galaxy in the Fornax Cluster. [2] The galaxy is 66 million light-years away from Earth. With a diameter of 130 000 light-years, it is one of the largest galaxies in the Fornax Cluster and slightly larger than the Milky Way. William Herschel discovered this galaxy on October 22, 1835.

Contents

Characteristics

It is a type-cD galaxy, with a bright center and a vast, diffuse envelope surrounding it. It is also an early-type galaxy, the largest one in the Fornax Cluster.

Despite their name, early-type galaxies are much older than spiral galaxies, and mostly comprise old, red-colored stars. Very little star formation occurs in these galaxies; the lack of star formation in elliptical galaxies appears to start at the center and then slowly propagates outward. [3]

Globular clusters

NGC 1399 is very rich in globular clusters. The population is estimated to be between 5700 and 6500. It has been proposed that NGC 1399 has a rich system of globular clusters because NGC 1404 gave up most of its globular clusters due to gravitational interactions. The estimated angular extent, measured from the NGC 1399 centre and up to a limiting radius where the areal density of blue globular clusters falls to 30 per cent of the background level, is 45±5 arcmin, which corresponds to 220–275 kpc at the Fornax distance. The bimodal colour distribution of this globular cluster system, as well as the different radial distribution of blue and red clusters, up to these large distances from the parent galaxy, are confirmed. The azimuthal globular cluster distribution exhibits asymmetries that might be understood in terms of tidal stripping of globulars from NGC 1387, another nearby galaxy. The good agreement between the areal density profile of blue clusters and a projected dark-matter NFW density profile is emphasized. [4]

Supermassive black hole

The core of NGC 1399 contains a supermassive black hole of 510 million solar masses, a factor of over 2 below the correlation of black hole mass and velocity dispersion. There is also a dramatic signature for central tangential anisotropy. The velocity profiles on adjacent sides 0.5" away from the nucleus show strong bimodality, and the central spectrum shows a large drop in the dispersion. Both of these observations point to an orbital distribution that is tangentially biased. The best-fit orbital model suggests a ratio of the tangential to radial internal velocity dispersions of 3. This ratio is the largest seen in any galaxy to date and will provide an important measure for the mode by which the central black hole has grown. [5]

Planetary nebulae

There are 37 planetary nebulae in this galaxy. Their magnitudes are around 27. The accuracy of the measured radial velocities of these planetary nebulae is about 70 km/s, which is much smaller than the velocity dispersion of the galaxy. [6]

NGC 1399 X-ray image of Chandra Ngc1399 X-ray resolution of intermediate black hole.jpg
NGC 1399 X-ray image of Chandra

Spectrum

A spectrum was taken as part of a study of giant elliptical galaxies to figure out why galaxies of this type do not form stars. The data collected with Herschel showed that, contrary to previous belief, most of these galaxies contain plenty of cold gas – the raw material to form stars – with the exception of NGC 1399 and one other.

A multi-wavelength study suggested that, while hot gas cools down in these galaxies, stars do not form because of feedback from the central supermassive black hole, which heats up the gas again or pushes it beyond the galaxy's reach. For most of the galaxies observed, the activity of the black hole seems to have put an end to star formation but has not yet succeeded in clearing them of all their cold gas, but in the case of NGC 1399 the feedback cycle appears to be at a more advanced stage, as the jets have hardly left any trace of cold gas. [7]

Ultraluminous X-ray source

In 2010, Chandra X-ray Observatory found an ultraluminous X-ray source (ULX). The ULX's position is in one of NGC 1399's globular clusters, a very old and crowded environment. Evidence from Chandra suggests that a white dwarf star has been torn apart by an intermediate-mass black hole, but this is only a proposal, and its true nature remains a mystery. If confirmed, it would be first black hole found in this setting. A 2019 study of globular cluster ULXs in NGC 1399 [8] has since disproven this proposal, as the source has remained X-ray bright far longer than is theoretically possible in the intermediate-mass black hole disrupting a white dwarf scenario.

Environment

VST image of the Fornax Galaxy Cluster VST image of the Fornax Galaxy Cluster.jpg
VST image of the Fornax Galaxy Cluster

NGC 1399 is the central galaxy of the Fornax Cluster, the second richest cluster within 100 megaparsecs. It is also the central galaxy of the main subgroup. Near NGC 1399 are NGC 1396, NGC 1404 and NGC 1387. There are ultracompact dwarf galaxies surrounding the galaxy, while NGC 1427A, an irregular galaxy, lies near its center.

Ultracompact dwarf galaxies were first discovered in the Fornax Cluster in 2003. Almost all of them surround NGC 1399, as it is the central galaxy of the cluster.

Related Research Articles

<span class="mw-page-title-main">Fornax</span> Constellation in the southern celestial hemisphere

Fornax is a constellation in the southern celestial hemisphere, partly ringed by the celestial river Eridanus. Its name is Latin for furnace. It was named by French astronomer Nicolas Louis de Lacaille in 1756. Fornax is one of the 88 modern constellations.

<span class="mw-page-title-main">Elliptical galaxy</span> Spherical or ovoid mass of stars

An elliptical galaxy is a type of galaxy with an approximately ellipsoidal shape and a smooth, nearly featureless image. They are one of the four main classes of galaxy described by Edwin Hubble in his Hubble sequence and 1936 work The Realm of the Nebulae, along with spiral and lenticular galaxies. Elliptical (E) galaxies are, together with lenticular galaxies (S0) with their large-scale disks, and ES galaxies with their intermediate scale disks, a subset of the "early-type" galaxy population.

<span class="mw-page-title-main">Messier 87</span> Elliptical galaxy in the Virgo Galaxy Cluster

Messier 87 is a supergiant elliptical galaxy in the constellation Virgo that contains several trillion stars. One of the largest and most massive galaxies in the local universe, it has a large population of globular clusters—about 15,000 compared with the 150–200 orbiting the Milky Way—and a jet of energetic plasma that originates at the core and extends at least 1,500 parsecs, traveling at a relativistic speed. It is one of the brightest radio sources in the sky and a popular target for both amateur and professional astronomers.

<span class="mw-page-title-main">Intermediate-mass black hole</span> Class of black holes with a mass range of 100 to 100000 solar masses

An intermediate-mass black hole (IMBH) is a class of black hole with mass in the range 102–105 solar masses: significantly more than stellar black holes but less than the 105–109 solar mass supermassive black holes. Several IMBH candidate objects have been discovered in our galaxy and others nearby, based on indirect gas cloud velocity and accretion disk spectra observations of various evidentiary strength.

<span class="mw-page-title-main">Sombrero Galaxy</span> Peculiar galaxy in the constellation Virgo

The Sombrero Galaxy (also known as Messier Object 104, M104 or NGC 4594) is a peculiar galaxy of unclear classification in the constellation borders of Virgo and Corvus, being about 9.55 megaparsecs (31.1 million light-years) from the Milky Way galaxy. It is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. It has a D25 isophotal diameter of approximately 29.09 kiloparsecs (94,900 light-years), making it slightly bigger in size than the Milky Way.

<span class="mw-page-title-main">Messier 60</span> Elliptical galaxy in the constellation Virgo

Messier 60 or M60, also known as NGC 4649, is an elliptical galaxy approximately 57 million light-years away in the equatorial constellation of Virgo. Together with NGC 4647, it forms a pair known as Arp 116. Messier 60 and nearby elliptical galaxy Messier 59 were discovered by Johann Gottfried Koehler in April 1779, observing a comet in the same part of the sky. Charles Messier added both to his catalogue about three days after this.

<span class="mw-page-title-main">Dwarf galaxy</span> Small galaxy composed of up to several billion stars

A dwarf galaxy is a small galaxy composed of about 1000 up to several billion stars, as compared to the Milky Way's 200–400 billion stars. The Large Magellanic Cloud, which closely orbits the Milky Way and contains over 30 billion stars, is sometimes classified as a dwarf galaxy; others consider it a full-fledged galaxy. Dwarf galaxies' formation and activity are thought to be heavily influenced by interactions with larger galaxies. Astronomers identify numerous types of dwarf galaxies, based on their shape and composition.

<span class="mw-page-title-main">NGC 1097</span> Galaxy in the constellation Fornax

NGC 1097 is a barred spiral galaxy about 45 million light years away in the constellation Fornax. It was discovered by William Herschel on 9 October 1790. It is a severely interacting galaxy with obvious tidal debris and distortions caused by interaction with the companion galaxy NGC 1097A.

<span class="mw-page-title-main">NGC 4889</span> Galaxy in the constellation Coma Berenices

NGC 4889 is an E4 supergiant elliptical galaxy. It was discovered in 1785 by the British astronomer Frederick William Herschel I, who catalogued it as a bright, nebulous patch. The brightest galaxy within the northern Coma Cluster, it is located at a median distance of 94 million parsecs from Earth. At the core of the galaxy is a supermassive black hole that heats the intracluster medium through the action of friction from infalling gases and dust. The gamma ray bursts from the galaxy extend out to several million light years of the cluster.

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<span class="mw-page-title-main">NGC 3377</span> Galaxy in the constellation Leo

NGC 3377 is an elliptical galaxy in the constellation Leo. It is a member of the M96 Group and is about 26 Mly away, with a diameter of approximately 40 000 ly. The supermassive black hole at the core of NGC 3377 has a mass of 8.0+0.5
−0.6×107 M☉. A very faint companion galaxy, NGC 3377A is 7.1' NW.

<span class="mw-page-title-main">NGC 1407</span> Elliptical galaxy in the constellation Eridanus

NGC 1407 is an elliptical galaxy in Eridanus. It is at a distance of 76 million light-years from Earth. It is the brightest galaxy in the NGC 1407 Group, part of the Eridanus Group, with NGC 1407 being its brightest member. NGC 1400, the second-brightest of the group lies 11.8 arcmin away.

<span class="mw-page-title-main">NGC 3311</span> Galaxy in the constellation Hydra

NGC 3311 is a supergiant elliptical galaxy located about 190 million light-years away in the constellation Hydra. The galaxy was discovered by astronomer John Herschel on March 30, 1835. NGC 3311 is the brightest member of the Hydra Cluster and forms a pair with NGC 3309 which along with NGC 3311, dominate the central region of the Hydra Cluster.

<span class="mw-page-title-main">NGC 3923</span> Elliptical galaxy in the constellation Hydra

NGC 3923 is an elliptical galaxy located in the constellation Hydra. It is located at a distance of circa 90 million light years from Earth, which, given its apparent dimensions, means that NGC 3923 is about 155,000 light years across. NGC 3923 is an example of a shell galaxy where the stars in its halo are arranged in layers. It has more than twenty shells. It was discovered by William Herschel on March 7, 1791.

<span class="mw-page-title-main">NGC 720</span> Galaxy in the constellation Cetus

NGC 720 is an elliptical galaxy located in the constellation Cetus. It is located at a distance of circa 80 million light years from Earth, which, given its apparent dimensions, means that NGC 720 is about 110,000 light years across. It was discovered by William Herschel on October 3, 1785. The galaxy is included in the Herschel 400 Catalogue. It lies about three and a half degrees south and slightly east from zeta Ceti.

<span class="mw-page-title-main">NGC 1380</span> Galaxy in the constellation Fornax

NGC 1380 is a lenticular galaxy located in the constellation Fornax. It is located at a distance of circa 60 million light years from Earth, which, given its apparent dimensions, means that NGC 1380 is about 85,000 light years across. It was discovered by James Dunlop on September 2, 1826. It is a member of the Fornax Cluster.

<span class="mw-page-title-main">NGC 4636</span> Galaxy in the constellation Virgo

NGC 4636 is an elliptical galaxy located in the constellation Virgo. It is a member of the NGC 4753 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. It is located at a distance of about 55 million light years from Earth, which, given its apparent dimensions, means that NGC 4636 is about 105,000 light years across.

<span class="mw-page-title-main">NGC 5846</span> Galaxy in the constellation Virgo

NGC 5846 is an elliptical galaxy located in the constellation Virgo. It is located at a distance of circa 90 million light years from Earth, which, given its apparent dimensions, means that NGC 5846 is about 110,000 light years across. It was discovered by William Herschel on February 24, 1786. It lies near 110 Virginis and is part of the Herschel 400 Catalogue. It is a member of the NGC 5846 Group of galaxies, itself one of the Virgo III Groups strung out to the east of the Virgo Supercluster of galaxies.

<span class="mw-page-title-main">NGC 1381</span> Galaxy in the constellation Fornax

NGC 1381 is a lenticular galaxy located in the constellation Fornax. It is located at a distance of about 60 million light years from Earth, which, given its apparent dimensions, means that NGC 1381 is about 55,000 light years across. It is a member of the Fornax Cluster. NGC 1381 appears edge-on and features a thin disk with high surface brightness and a boxy bulge. Both the box-shaped bulge and the kinematics of the central area of the galaxy suggest that NGC 1381 has a bar.

<span class="mw-page-title-main">NGC 1332</span> Elliptical galaxy in the constellation Eridanus

NGC 1332 is an almost edge-on elliptical galaxy located in constellation of Eridanus. Situated about 70 million light years away, it is a member of the Eridanus cluster of galaxies, a cluster of about 200 galaxies. It is also the brightest member of the NGC 1332 Group. It was discovered by William Herschel on 9 December 1784.

References

  1. 1 2 3 4 5 Dunlop, Storm (2005). Atlas of the Night Sky. Collins. ISBN   978-0-00-717223-8.
  2. ↑ "Multiwavelength Atlas of Galaxies - NGC 1399" . Retrieved 2011-06-18.
  3. ↑ Howell, Elizabeth (2015). "Colossal Ancient Galaxies Die from the Inside Out". space.com. Retrieved 5 March 2017.
  4. ↑ Bassino, L. P.; Faifer, F. R.; Forte, J. C.; Dirsch, B.; Richtler, T.; Geisler, D.; Schuberth, Y. (2006). "Large-scale study of the NGC 1399 globular cluster system in Fornax". Astronomy & Astrophysics. 451 (3): 789–796. arXiv: astro-ph/0603349 . Bibcode:2006A&A...451..789B. doi:10.1051/0004-6361:20054563. S2CID   15549056.
  5. ↑ GEBHARDT, K.; LAUER, T. R.; PINKNEY, J.; BENDER, R.; RICHSTONE, D.; ALLER, M.; BOWER, G.; DRESSLER, A. (December 2007). "The Black Hole Mass and Extreme Orbital Structure in NGC 1399". The Astrophysical Journal. 671 (2): 1321–1328. arXiv: 0709.0585 . Bibcode:2007ApJ...671.1321G. doi:10.1086/522938. hdl:2152/35191. S2CID   12042010.
  6. ↑ "Planetary nebulae in NGC 1399". European Southern Observatory. Retrieved 28 July 2019.
  7. ↑ "ESA Science & Technology - Herschel spectrum of the elliptical galaxy NGC 1399".
  8. ↑ Dage, Kristen C.; Zepf, Stephen E.; Peacock, Mark B.; Bahramian, Arash; Noroozi, Omid; Kundu, Arunav; MacCarone, Thomas J. (2019). "X-ray spectral variability of ultraluminous X-ray sources in extragalactic globular clusters". Monthly Notices of the Royal Astronomical Society. 485 (2): 1694. arXiv: 1902.05073 . Bibcode:2019MNRAS.485.1694D. doi:10.1093/mnras/stz479.
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