Cloverleaf quasar

Molecular 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

{{cite journal

|author1=S. Venturini |author2=P. M. Solomon | title = The Molecular Disk in the Cloverleaf Quasar

| date = 2003

| journal = Astrophysical Journal

| volume = 590 |issue=2 | pages = 740–745

| bibcode = 2003ApJ...590..740V

| doi = 10.1086/375050

|arxiv = astro-ph/0210529 |s2cid=761080 }} and was also the first source at a redshift {{nowrap|z {{=}} 2.56}} to be detected with HCN

{{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 |s2cid=4414417 }} or HCO⁺ emission.

{{cite journal

| author = D. A. Riechers

| date = 2006

| title = First Detection of HCO⁺ Emission at High Redshift

| journal = Astrophysical Journal Letters

| volume = 645 | issue = 1

| pages = L13–L16

| bibcode = 2006ApJ...645L..13R

| doi = 10.1086/505908

|arxiv = astro-ph/0605437 | s2cid = 17504751

|display-authors=etal}} This suggests the quasar is currently undergoing an intense wave of star formations thus increasing its luminosity. A radio jet has also been found on the side of quasar according to a study published in 2023.{{Cite journal |last1=Zhang |first1=Lei |last2=Zhang |first2=Zhi-Yu |last3=Nightingale |first3=James W. |last4=Zou |first4=Ze-Cheng |last5=Cao |first5=Xiaoyue |last6=Tsai |first6=Chao-Wei |last7=Yang |first7=Chentao |last8=Shi |first8=Yong |last9=Wang |first9=Junzhi |last10=Xu |first10=Dandan |last11=Lin |first11=Ling-Rui |last12=Zhou |first12=Jing |last13=Li |first13=Ran |date=2023-09-01 |title=Discovery of a radio jet in the Cloverleaf quasar at z = 2.56 |journal=Monthly Notices of the Royal Astronomical Society |volume=524 |issue=3 |pages=3671–3682 |doi=10.1093/mnras/stad2069 |doi-access=free |arxiv=2212.07027 |bibcode=2023MNRAS.524.3671Z |issn=0035-8711}}

File:The "cloverleaf" quasar H 1413+117 (eso8806a).jpg

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.{{Cite web |title=Chandra :: Photo Album :: Cloverleaf Quasar (a.k.a. H1413+117) :: More Images of the Cloverleaf Quasar |url=https://chandra.harvard.edu/photo/2004/h1413/more.html |access-date=2024-08-28 |website=chandra.harvard.edu}}

The X-rays would be magnified much more than the visible light

if they came from a region around the central supermassive black hole of the lensing galaxy that was smaller than the origin region of 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. Additionally, inner regions of the quasar's accretion disk around the black hole has been detected suggesting outflow wind.{{Cite journal |last1=Chartas |first1=G. |last2=Eracleous |first2=M. |last3=Dai |first3=X. |last4=Agol |first4=E. |last5=Gallagher |first5=S. |date=2007-06-01 |title=Discovery of Probable Relativistic Fe Emission and Absorption in the Cloverleaf Quasar H 1413+117 |url=https://ui.adsabs.harvard.edu/abs/2007ApJ...661..678C/abstract |journal=The Astrophysical Journal |volume=661 |issue=2 |pages=678–692 |doi=10.1086/516816 |arxiv=astro-ph/0702742 |bibcode=2007ApJ...661..678C |issn=0004-637X}}

Data from NICMOS and a special algorithm resolved the lensing galaxy and a partial Einstein ring. The Einstein ring represents the host galaxy of the lensed quasar.{{Cite journal|last1=Chantry|first1=Virginie|last2=Magain|first2=Pierre|date=August 2007|title=Deconvolution of HST images of the Cloverleaf gravitational lens : detection of the lensing galaxy and a partial Einstein ring|journal=Astronomy & Astrophysics|volume=470|issue=2|pages=467–473|doi=10.1051/0004-6361:20066839|arxiv=astro-ph/0612094|bibcode=2007A&A...470..467C|issn=0004-6361|doi-access=free}}

The Cloverleaf quasar was discovered in 1988. Data on the Cloverleaf collected by the Chandra X-ray Observatory in 2004 were 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 found 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.

File:Coverleaf Quasar HST ACS+HRC.png|Quadruple image of the quasar taken with Hubble Space Telescope.

File:Gravitational Lensing Graphic - PIA23641.tiff|Graphic illustration of four images of the quasar caused by gravitational lensing.

• List of quasars

{{reflist}}

• {{cite journal

|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|s2cid=4246365 }}

• {{cite journal

|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 |s2cid=13889803

|display-authors=etal}}

• Chandra at Havard CfA, [http://chandra.harvard.edu/photo/2004/h1413/ "Cloverleaf Quasar: Chandra Looks Over a Cosmic Four-Leaf Clover"], 20 February 2009

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Category:Gravitationally lensed quasars

Category:Boötes