| 词条 | Cloverleaf quasar |
| 释义 |
| name = Cloverleaf, H1413+117, QSO 1415+1129 | image = | caption= | epoch = J2000 | ra = {{RA| 14 | 15 | 46.27 }} | dec = {{DEC| +11 | 29 | 43.4 }} | constellation name = | z = 2.56 | type = | dist_ly = 11,000,000,000 ly | appmag_v = 17 | size_v = | notes = Four-image lens, bright CO emission | names = QSO J1415+1129 , QSO B1413+1143 , H 1413+117 , Clover Leaf Quasar }} The Cloverleaf quasar (H1413+117, QSO J1415+1129) is a bright, gravitationally lensed quasar. QuasarMolecular gas (notably CO) detected in the host galaxy associated with the quasar is the oldest molecular material known and provides evidence of large-scale star formation in the early universe. Thanks to the strong magnification provided by the foreground lens, the Cloverleaf is the brightest known source of CO emission at high redshift[1] and was also the first source at a redshift {{nowrap|z {{=}} 2.56}} to be detected with HCN[2] or HCO+ emission.[3] The 4 quasar images were originally discovered in 1984; in 1988, they were determined to be a single quasar split into four images, instead of 4 separate quasars. The X-rays from iron atoms were also enhanced relative to X-rays at lower energies. Since the amount of brightening due to gravitational lensing doesn't vary with the wavelength, this means that an additional object has magnified the X-rays. The increased magnification of the X-ray light can be explained by gravitational microlensing, an effect which has been used to search for compact stars and planets in our galaxy. Microlensing occurs when a star or a multiple star system passes in front of light from a background object. If a single star or a multiple star system in one of the foreground galaxies passed in front of the light path for the brightest image, then that image would be selectively magnified. Black holeThe X-rays would be magnified much more than the visible light, if they came from a smaller region around the central supermassive black hole of the lensing galaxy than did the visible light. The enhancement of the X-rays from iron ions would be due to this same effect. The analysis indicates that the X-rays are coming from a very small region, about the size of the solar system, around the central black hole. The visible light is coming from a region ten or more times larger. The angular size of these regions at a distance of 11 billion light years is tens of thousands times smaller than the smallest region that can be resolved by the Hubble Space Telescope. This provides a way to test models for the flow of gas around a supermassive black hole. HistoryThe Cloverleaf quasar was discovered in 1988. Data on the Cloverleaf collected by the Chandra X-ray Observatory in 2004 was compared with that gathered by optical telescopes. One of the X-ray components (A) in the Cloverleaf is brighter than the others in both optical and X-ray light but was to be relatively brighter in X-ray than in optical light. The X-rays from iron atoms were also enhanced relative to X-rays at lower energies. See also
References1. ^{{cite journal |author1=S. Venturini |author2=P. M. Solomon | title = The Molecular Disk in the Cloverleaf Quasar | date = 2003 | journal = Astrophysical Journal | volume = 590 | pages = 740–745 | bibcode = 2003ApJ...590..740V | doi = 10.1086/375050|arxiv = astro-ph/0210529 }} 2. ^{{cite journal |author1=P. Solomon |author2=P. Vanden Bout |author3=C. Carilli |author4=M. Guelin | date = 2003 | title = The Essential Signature of a Massive Starburst in a Distant Quasar| journal = Nature | volume = 426 | issue = 6967 | pages = 636–638 | bibcode = 2003Natur.426..636S | doi = 10.1038/nature02149 | pmid = 14668856|arxiv = astro-ph/0312436 }} 3. ^{{cite journal | author = D. A. Riechers | date = 2006 | title = First Detection of HCO+ Emission at High Redshift | journal = Astrophysical Journal Letters | volume = 645 | pages = L13–L16 | bibcode = 2006ApJ...645L..13R | doi = 10.1086/505908|arxiv = astro-ph/0605437 |display-authors=etal}} Further reading
|author1=R. Barvainis |author2=L. Tacconi |author3=R. Antonucci |author4=D. Alloin |author5=P. Coleman |date=2002 |title=Extremely strong carbon monoxide emission from the Cloverleaf quasar at a redshift of 2.5 |journal=Nature |volume=371 |pages=586–588 |doi=10.1038/371586a0 |bibcode = 1994Natur.371..586B |issue=6498}}
|author=C. M. Bradford |date=2009 |title=The Warm Molecular Gas Around the Cloverleaf Quasar |journal=Astrophysical Journal |volume=705 |issue=1 |page=112 |doi=10.1088/0004-637X/705/1/112 |bibcode=2009ApJ...705..112B |arxiv = 0908.1818 |display-authors=etal}} External links
1 : Gravitationally lensed quasars |
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