HE0450-2958 is an unusual quasar. It has been called the "naked quasar" and the "quasar without a home" because it appears to lack a host galaxy. It is estimated to lie approximately one billion parsecs away.
HE0450-2958
Quasar HE0450-2958 as imaged by the HST. The quasar is near the center of the image; no obvious host galaxy is seen. Near the top of the image is a strongly disturbed and star-forming galaxy. Near the quasar is a blob of gas that is apparently being ionized by the quasar radiation. The pointlike object on the lower right is a foreground star seen by chance in the field of view.
A team of researchers led by Pierre Magain of the University of Liège, Belgium announced their findings in the September 14, 2005 issue of the journal Nature.[2] The quasar lies close in the sky to a disturbed, starburstgalaxy (see figure, upper left). However, no galaxy was seen around the quasar itself (figure, middle), leading the authors to speculate
One might suggest that the host galaxy has disappeared from our view as a result of the collision [which formed the disturbed galaxy], but it is hard to imagine how the complete disruption of a galaxy could happen.
In order for the quasar's host galaxy to have escaped detection, Magain et al. estimated that it would need to be approximately five magnitudes (100 times) dimmer than expected for such a quasar, or to have a radius of 300 light-years or less (typical quasars are embedded in galaxies 5000 to 50,000 light-years across).
Shortly after Magain et al.'s paper was published, three theoretical papers appeared, all in the week of November 6, 2005, which claimed to explain the peculiar properties of this object. Two of the papers—from groups in Cambridge, Massachusetts[3] and Cambridge, England[4]—suggested that the quasar was a supermassive black hole that had been ejected from the center of the nearby, disturbed galaxy, either by gravitational radiation recoil or by an interaction involving three black holes. The ejection velocity would have to be approximately 1000 km/s in order to place the quasar so far from its original host galaxy.
The third paper,[5] from a team led by David Merritt, critically examined the ejection hypothesis and concluded that it could not be correct. The two main arguments were: (1) The quasar spectrum reveals it to be a narrow-line Seyfert 1 galaxy. NLS1's are believed to have abnormally small black holes; since black hole size is strongly correlated with galaxy size, the host galaxy of the quasar should also be abnormally small, explaining why it had not been detected by Magain et al. (2) The quasar spectrum also reveals the presence of a classic, narrow emission line region (NLR). The gas producing the narrow lines lies roughly a thousand light-years from the black hole, and such gas could not remain bound to the black hole following a kick large enough to remove it from its host galaxy. These authors concluded that the "naked" quasar was in fact a perfectly normal, narrow-line Seyfert galaxy that happened to lie close on the sky to a disturbed galaxy.
The "quasar without a home".
A number of scientific studies since 2005 have supported this conclusion. (1) Kim et al. (2006) [6] made a more careful attempt to find the quasar's host galaxy. They concluded that it was impossible to rule out the presence of a galaxy given the confusing light from the quasar. (2) Zhou et al. (2007) [7] observed the X-ray emission from the quasar and used it to estimate the mass of the black hole. They confirmed a small mass for the black hole, implying an even fainter host galaxy than predicted by Merritt et al. (3) Feain et al. (2007) [8] detected radio emission from the quasar, which they interpreted as indicating ongoing star formation, which "contradicts any suggestion that this is a 'naked' quasar'".
The current scientific consensus is that HE0450-2958 probably does have a host galaxy but that it is difficult to see behind the bright quasar light.
Recently, the consensus has been questioned after a European Southern Observatory study.[9]
A study in 2010 discovered a "blob" of emission near the quasar. This blob is thought to be the disturbed and compact host galaxy for the quasar.[10]
^ abcdef"Nasa/Ipac Extragalactic Database". Results for HB89 0450-299. Retrieved 2006-11-27.
^ abMagain, P. et al. (2005), Discovery of a bright quasar without a massive host galaxy, Nature, 437, 381
^Hoffman, L. and Loeb, A. (2005), Three-Body Kick to a Bright Quasar out of Its Galaxy During a Merger, arXiv:astro-ph/0511242
^Haehnelt, M. et al. (2005), Possible evidence for the ejection of a supermassive black hole from an ongoing merger of galaxies, arXiv:astro-ph/0511245
^Kim, M. et al. (2006), The Host Galaxy of the Quasar HE 0450-2958, The Astrophysical Journal, 658, 107
^Zhou, X.-L. et al. (2007), X-Ray Properties of the Quasar HE 0450-2958, The Astronomical Journal, 133, 432
^Feain, I. et al. (2007), Dressing a Naked Quasar: Star Formation and Active Galactic Nucleus Feedback in HE 0450-2958, The Astrophysical Journal, 662, 872
^Elbaz.D. et al. (2009) Quasar induced galaxy formation: a new paradigm? Astronomy & Astrophysics 507, 1359–1374
^Letawe, G.; Magain, P. (2010). "Deep near-infrared imaging of the HE0450-2958 system". Astronomy and Astrophysics. 515: A84. arXiv:1003.3746. Bibcode:2010A&A...515A..84L. doi:10.1051/0004-6361/201014175. S2CID 53142733.
he0450, 2958, unusual, quasar, been, called, naked, quasar, quasar, without, home, because, appears, lack, host, galaxy, estimated, approximately, billion, parsecs, away, quasar, imaged, quasar, near, center, image, obvious, host, galaxy, seen, near, image, st. HE0450 2958 is an unusual quasar It has been called the naked quasar and the quasar without a home because it appears to lack a host galaxy It is estimated to lie approximately one billion parsecs away HE0450 2958Quasar HE0450 2958 as imaged by the HST The quasar is near the center of the image no obvious host galaxy is seen Near the top of the image is a strongly disturbed and star forming galaxy Near the quasar is a blob of gas that is apparently being ionized by the quasar radiation The pointlike object on the lower right is a foreground star seen by chance in the field of view Observation data Epoch J2000 ConstellationCaelumRight ascension04h 52m 30 0s 1 Declination 29 53 35 1 Redshift0 286041 0 000093 73867 28 km s 1 Distance3 billion light years 1 Gpc 2 TypeSy1 1 Apparent magnitude V 16 0 1 Other designationsLEDA 75249 1 QSO B0450 2958 2MASSI J0452300 295335 6dFGS gJ045230 1 295335 2MASX J04523006 2953353 NVSS J045230 295336 IRAS F04505 2958 QSO B0450 299 IRAS 04505 2958 RBS 597 1RXS J045230 4 295329See also Quasar List of quasars Contents 1 History 2 See also 3 References 4 External linksHistory EditA team of researchers led by Pierre Magain of the University of Liege Belgium announced their findings in the September 14 2005 issue of the journal Nature 2 The quasar lies close in the sky to a disturbed starburst galaxy see figure upper left However no galaxy was seen around the quasar itself figure middle leading the authors to speculate One might suggest that the host galaxy has disappeared from our view as a result of the collision which formed the disturbed galaxy but it is hard to imagine how the complete disruption of a galaxy could happen In order for the quasar s host galaxy to have escaped detection Magain et al estimated that it would need to be approximately five magnitudes 100 times dimmer than expected for such a quasar or to have a radius of 300 light years or less typical quasars are embedded in galaxies 5000 to 50 000 light years across Shortly after Magain et al s paper was published three theoretical papers appeared all in the week of November 6 2005 which claimed to explain the peculiar properties of this object Two of the papers from groups in Cambridge Massachusetts 3 and Cambridge England 4 suggested that the quasar was a supermassive black hole that had been ejected from the center of the nearby disturbed galaxy either by gravitational radiation recoil or by an interaction involving three black holes The ejection velocity would have to be approximately 1000 km s in order to place the quasar so far from its original host galaxy The third paper 5 from a team led by David Merritt critically examined the ejection hypothesis and concluded that it could not be correct The two main arguments were 1 The quasar spectrum reveals it to be a narrow line Seyfert 1 galaxy NLS1 s are believed to have abnormally small black holes since black hole size is strongly correlated with galaxy size the host galaxy of the quasar should also be abnormally small explaining why it had not been detected by Magain et al 2 The quasar spectrum also reveals the presence of a classic narrow emission line region NLR The gas producing the narrow lines lies roughly a thousand light years from the black hole and such gas could not remain bound to the black hole following a kick large enough to remove it from its host galaxy These authors concluded that the naked quasar was in fact a perfectly normal narrow line Seyfert galaxy that happened to lie close on the sky to a disturbed galaxy The quasar without a home A number of scientific studies since 2005 have supported this conclusion 1 Kim et al 2006 6 made a more careful attempt to find the quasar s host galaxy They concluded that it was impossible to rule out the presence of a galaxy given the confusing light from the quasar 2 Zhou et al 2007 7 observed the X ray emission from the quasar and used it to estimate the mass of the black hole They confirmed a small mass for the black hole implying an even fainter host galaxy than predicted by Merritt et al 3 Feain et al 2007 8 detected radio emission from the quasar which they interpreted as indicating ongoing star formation which contradicts any suggestion that this is a naked quasar The current scientific consensus is that HE0450 2958 probably does have a host galaxy but that it is difficult to see behind the bright quasar light Recently the consensus has been questioned after a European Southern Observatory study 9 A study in 2010 discovered a blob of emission near the quasar This blob is thought to be the disturbed and compact host galaxy for the quasar 10 See also EditDark galaxyReferences Edit a b c d e f Nasa Ipac Extragalactic Database Results for HB89 0450 299 Retrieved 2006 11 27 a b Magain P et al 2005 Discovery of a bright quasar without a massive host galaxy Nature 437 381 Hoffman L and Loeb A 2005 Three Body Kick to a Bright Quasar out of Its Galaxy During a Merger arXiv astro ph 0511242 Haehnelt M et al 2005 Possible evidence for the ejection of a supermassive black hole from an ongoing merger of galaxies arXiv astro ph 0511245 Merritt David et al April 2006 The nature of the HE0450 2958 system Monthly Notices of the Royal Astronomical Society 367 4 1746 1750 arXiv astro ph 0511315 Bibcode 2006MNRAS 367 1746M doi 10 1111 j 1365 2966 2006 10093 x S2CID 55834970 Kim M et al 2006 The Host Galaxy of the Quasar HE 0450 2958 The Astrophysical Journal 658 107 Zhou X L et al 2007 X Ray Properties of the Quasar HE 0450 2958 The Astronomical Journal 133 432 Feain I et al 2007 Dressing a Naked Quasar Star Formation and Active Galactic Nucleus Feedback in HE 0450 2958 The Astrophysical Journal 662 872 Elbaz D et al 2009 Quasar induced galaxy formation a new paradigm Astronomy amp Astrophysics 507 1359 1374 Letawe G Magain P 2010 Deep near infrared imaging of the HE0450 2958 system Astronomy and Astrophysics 515 A84 arXiv 1003 3746 Bibcode 2010A amp A 515A 84L doi 10 1051 0004 6361 201014175 S2CID 53142733 External links EditBlack Hole in Search of a Home ESO Image HE0450 2958 Black Hole Caught Zapping Galaxy into Existence 1 Retrieved from https en wikipedia org w index php title HE0450 2958 amp oldid 1144770235, wikipedia, wiki, book, books, library,
