Observation data Epoch J2000 Equinox J2000 | |
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Constellation | Phoenix [2] |
Right ascension | 01h 10m 28.2s |
Declination | −46° 04′ 22.2″ [3] |
Details | |
Mass | 102–105 M☉ |
Hyper-Luminous X-ray source 1, commonly known as HLX-1, is an intermediate-mass black hole candidate located in the lenticular galaxy ESO 243-49 about 290 million light-years from Earth. The mass of its central black hole is estimated to be approximately 20,000 solar masses. [4] The source was discovered at the Institut de Recherche en Astrophysique et Planétologie (IRAP, formerly the CESR), Toulouse, France and gained interest from the scientific community because of strong evidence supporting it as an intermediate-mass black hole. [3] HLX-1 is possibly the remnant of a dwarf galaxy that may have been in a galactic collision with ESO 243-49. [5]
The object was first observed in November 2004, in which it was seen as a source emitting X-rays in the outskirts of the spiral galaxy ESO 243-49 and was catalogued as 2XMM J011028.1-460421, but nicknamed "HLX-1". [6] In 2008, a team of astronomers led by Natalie Webb at the Institut de Recherche en Astrophysique et Planétologie in Toulouse, France, discovered HLX-1 and from the very high X-ray luminosity (~1×1042 erg s−1, 0.2–10.0 keV), as well as its X-ray characteristics, proposed that it was an intermediate mass black hole candidate. [3]
Follow up analysis using further X-ray, [7] [8] [9] [10] [11] optical [12] [13] and radio [14] observations support the intermediate-mass black hole nature. In 2012, further work showed that there was a small cluster of stars amassed around HLX-1, leading Sean Farrell and collaborators [12] to conclude that the black hole was once the galactic center of a dwarf galaxy, which was consumed by ESO 243-49. [15] [16] Farrell remarked, "The fact that there's a very young cluster of stars indicates that the intermediate-mass black hole may have originated as the central black hole in a very low-mass dwarf galaxy. The dwarf galaxy was then swallowed by the more massive galaxy.". [17]
ESO 243-49 | |
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Observation data (J2000 epoch) | |
Right ascension | 01h 10m 27.755s [18] |
Declination | −46° 04′ 27.34″ [18] |
Heliocentric radial velocity | 6,782 km/s [19] |
Distance | 376.2 Mly (115.35 Mpc) [19] |
Group or cluster | Abell A2870 [19] |
Apparent magnitude (B) | 14.92 [20] |
Characteristics | |
Type | S0a [21] |
Apparent size (V) | 46.6″ × 14.0″ [22] (NIR) |
Other designations | |
2MASX J01102774-4604274, LEDA 4181 [23] |
ESO 243-49 is a lenticular galaxy in the southern constellation of Phoenix. It is located at a distance of approximately 380 million light-years from the Milky Way galaxy. [19] ESO 243-49 is a member of the Abell 2877 galaxy cluster, which has 89 known members. It lies at a projected separation of about 0.98 Mly (0.3 Mpc) from the dominant central cluster galaxy, IC 1633. [21]
The morphological classification of ESO 243-49 is S0a, indicating this is a lenticular galaxy. It is being viewed edge-on from the perspective of the Earth. An attempt in 2015 to detect radio continuum emission of neutral hydrogen from this galaxy was unsuccessful, suggesting it is a gas poor galaxy compared to similar field galaxies. This may be the result of its gas reservoir being depleted due to its location near the center of a galaxy cluster. [21]
The galaxy has prominent dust lanes around the nucleus, while UV emission from the bulge region suggests star formation is in progress. These may be indications that the galaxy has recently undergone a minor merger event. [24] In contrast, the disk of the galaxy consists of old stars that suggest general star formation was quenched a few billion years after the galaxy formed. [25]
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.
An intermediate-mass black hole (IMBH) is a class of black hole with mass in the range of tens to tens thousand (102–105) solar masses: significantly higher than stellar black holes but lower than the tens thousand to hundreds trillion (105–1015) solar mass supermassive black holes. Several IMBH candidate objects have been discovered in the Milky Way galaxy and others nearby, based on indirect gas cloud velocity and accretion disk spectra observations of various evidentiary strength.
A stellar black hole is a black hole formed by the gravitational collapse of a star. They have masses ranging from about 5 to several tens of solar masses. They are the remnants of supernova explosions, which may be observed as a type of gamma ray burst. These black holes are also referred to as collapsars.
Sagittarius A*, abbreviated as Sgr A*, is the supermassive black hole at the Galactic Center of the Milky Way. Viewed from Earth, it is located near the border of the constellations Sagittarius and Scorpius, about 5.6° south of the ecliptic, visually close to the Butterfly Cluster (M6) and Lambda Scorpii.
An ultraluminous X-ray source (ULX) is an astronomical source of X-rays that is less luminous than an active galactic nucleus but is more consistently luminous than any known stellar process (over 1039 erg/s, or 1032 watts), assuming that it radiates isotropically (the same in all directions). Typically there is about one ULX per galaxy in galaxies which host them, but some galaxies contain many. The Milky Way has not been shown to contain a ULX, although SS 433 may be a possible source. The main interest in ULXs stems from their luminosity exceeding the Eddington luminosity of neutron stars and even stellar black holes. It is not known what powers ULXs; models include beamed emission of stellar mass objects, accreting intermediate-mass black holes, and super-Eddington emission.
NGC 3607 is a small but fairly bright lenticular galaxy in the equatorial constellation of Leo, about 2.5° south of the prominent star Delta Leonis. The galaxy was discovered March 14, 1784 by William Herschel. Dreyer described it as "very bright, large, round, very much brighter middle, 2nd of 3". It is located at a distance of 73 million light years and is receding with a radial velocity of 930 km/s. The galaxy lies southwest of NGC 3626 at an angular separation of ~50′. It occupies the center of the Leo II Group of galaxies, forming one of its two brightest members – the other being NGC 3608. It is a member of the NGC 3607 Group of galaxies, which is a member of the Leo II Groups, a series of galaxies and galaxy clusters strung out from the right edge of the Virgo Supercluster.
NGC 1313 is a field galaxy and a irregular galaxy discovered by the Scottish astronomer James Dunlop on 27 September 1826. It has a diameter of about 50,000 light-years, or about half the size of the Milky Way.
NGC 3621 is a field spiral galaxy about 22 Mly (6.7 Mpc) away in the equatorial constellation of Hydra. It is comparatively bright and can be well seen in moderate-sized telescopes. The galaxy is around 93,000 ly (29,000 pc) across and is inclined at an angle of 66° from being viewed face on. It shines with a luminosity equal to 13 billion times that of the Sun. The morphological classification is SA(s)d, which indicates this is an ordinary spiral with loosely wound arms. There is no evidence for a bulge. Although it appears to be isolated, NGC 3621 belongs to the Leo spur.
NGC 5286 is a globular cluster of stars located some 35,900 light years away in the constellation Centaurus. At this distance, the light from the cluster has undergone reddening from interstellar gas and dust equal to E(B – V) = 0.24 magnitude in the UBV photometric system. The cluster lies 4 arc-minutes north of the naked-eye star M Centauri. It was discovered by Scottish astronomer James Dunlop, active in Australia, and listed in his 1827 catalog.
NGC 4102 is an intermediate barred spiral galaxy located in the northern constellation of Ursa Major. It is visible in a small telescope and has an apparent visual magnitude of 11.2. The galaxy was discovered April 12, 1789 by William Herschel. J. L. E. Dreyer described it as "bright, pretty small, round, brighter middle and bright nucleus". This galaxy is located at a distance of 60 million light years and is receding with a heliocentric radial velocity of 837 km/s. It is a member of the Ursa Major group of galaxies.
NGC 6388 is a globular cluster of stars located in the southern constellation of Scorpius. The cluster was discovered by Scottish astronomer James Dunlop on May 13, 1826 using a 20 cm (9 in) reflector telescope. It was later determined to be a globular cluster by English astronomer John Herschel, who was able to resolve it into individual stars. NGC 6388 is located at a distance of approximately 35,600 light-years (10.90 kpc) from the Sun. Due to its apparent visual magnitude of +6.8, binoculars or a small telescope are required to view it.
NGC 1271 is a compact elliptical or lenticular galaxy located about 250 million light-years away in the constellation Perseus. The galaxy was discovered by astronomer Guillaume Bigourdan on November 14, 1884. NGC 1271 is a member of the Perseus Cluster and has a nuclear dust disk in its center. It also has an edge-on, intermediate-scale disk and has a central bulge. Like NGC 1277, NGC 1271 is a candidate "relic galaxy".
NGC 2835 is an intermediate spiral galaxy located in the constellation Hydra. It is located at a distance of circa 35 million light years from Earth, which, given its apparent dimensions, means that NGC 2835 is about 65,000 light years across. It was discovered by Wilhelm Tempel on April 13, 1884. NGC 2835 is located only 18.5 degrees from the galactic plane.
NGC 1395 is an elliptical galaxy located in the constellation Eridanus. It is located at a distance of circa 75 million light years from Earth, which, given its apparent dimensions, means that NGC 1395 is about 130,000 light years across. It was discovered by William Herschel on November 17, 1784. It is a member of the Eridanus Cluster.
NGC 3585 is an elliptical or a lenticular galaxy located in the constellation Hydra. It is located at a distance of circa 60 million light-years from Earth, which, given its apparent dimensions, means that NGC 3585 is about 80,000 light years across. It was discovered by William Herschel on December 9, 1784.
NGC 4294 is a barred spiral galaxy with flocculent spiral arms located about 55 million light-years away in the constellation Virgo. The galaxy was discovered by astronomer William Herschel on March 15, 1784 and is a member of the Virgo Cluster.
NGC 4298 is a flocculent spiral galaxy located about 53 million light-years away in the constellation Coma Berenices. The galaxy was discovered by astronomer William Herschel on April 8, 1784 and is a member of the Virgo Cluster.
NGC 4318 is a small lenticular galaxy located about 72 million light-years away in the constellation Virgo. It was discovered by astronomer John Herschel on January 18, 1828. NGC 4318 is a member of the Virgo W′ group, a group of galaxies in the background of the Virgo Cluster that is centered on the giant elliptical galaxy NGC 4365.