Editing Eta Carinae (section)

===High energy radiation===
[[File:EtaCarinaeStarSystem-ChandraXRayObservatory-20140826.jpg|thumb|upright=1.1|right|alt=An X-ray image of η&nbsp;Carinae from [[Chandra X-Ray Observatory]] |X-rays around η&nbsp;Carinae (red is low energy, blue higher)]]
Several [[X-ray]] and [[gamma ray]] sources have been detected around η&nbsp;Carinae, for example 4U 1037–60 in the 4th [[Uhuru (satellite)|Uhuru]] catalogue and 1044–59 in the [[HEAO-2]] catalog. The earliest detection of X-rays in the η&nbsp;Carinae region was from the Terrier-Sandhawk rocket,<ref name="hill">{{cite journal|bibcode=1972ApJ...171..519H |title=A Soft X-Ray Survey from the Galactic Center to VELA|journal=The Astrophysical Journal|volume=171|pages=519|last1=Hill|first1=R. W.|last2=Burginyon|first2=G. |last3=Grader|first3=R. J.|last4=Palmieri|first4=T. M.|last5=Seward|first5=F. D.|last6=Stoering|first6=J. P.|year=1972|doi=10.1086/151305}}</ref> followed by [[Ariel 5]],<ref name="seward1976">{{cite journal|bibcode=1976MNRAS.177P..13S|title=X-ray sources in the southern Milky Way|journal=Monthly Notices of the Royal Astronomical Society|volume=177|pages=13P–20P |last1=Seward|first1=F. D.|last2=Page|first2=C. G.|last3=Turner|first3=M. J. L.|last4=Pounds|first4=K. A.|year=1976|doi=10.1093/mnras/177.1.13p|doi-access=free}}</ref> [[OSO 8]],<ref name="becker1976">{{cite journal|bibcode=1976ApJ...209L..65B|title=X-ray emission from the supernova remnant G287.8–0.5|journal=The Astrophysical Journal|volume=209|pages=L65|last1=Becker|first1=R. H. |last2=Boldt|first2=E. A.|last3=Holt|first3=S. S.|last4=Pravdo|first4=S. H.|last5=Rothschild|first5=R. E.|last6=Serlemitsos|first6=P. J.|last7=Swank|first7=J. H. |year=1976|doi=10.1086/182269|hdl=2060/19760020047|s2cid=122613896 |hdl-access=free}}</ref> and Uhuru<ref name="forman1978">{{cite journal|bibcode=1978ApJS...38..357F|title=The fourth Uhuru catalog of X-ray sources|journal=The Astrophysical Journal |volume=38|pages=357|last1=Forman|first1=W.|last2=Jones|first2=C.|last3=Cominsky|first3=L.|last4=Julien|first4=P.|last5=Murray|first5=S.|last6=Peters|first6=G. |last7=Tananbaum|first7=H.|last8=Giacconi|first8=R. |display-authors=6 |year=1978|doi=10.1086/190561|doi-access=free}}</ref> sightings.

More detailed observations were made with the [[Einstein Observatory]],<ref name="seward1979">{{cite journal|bibcode=1979ApJ...234L..55S|title=X-rays from Eta Carinae and the surrounding nebula|journal=The Astrophysical Journal|volume=234|pages=L55|last1=Seward|first1=F. D.|last2=Forman|first2=W. R.|last3=Giacconi|first3=R.|last4=Griffiths|first4=R. E. |last5=Harnden|first5=F. R.|last6=Jones|first6=C.|last7=Pye|first7=J. P.|year=1979|doi=10.1086/183108}}</ref> [[ROSAT]] X-ray telescope,<ref name=corcoran1995>{{cite journal |bibcode=1995ApJ...445L.121C|title=First detection of x-ray variability of Eta Carinae|journal=The Astrophysical Journal|volume=445|pages=L121|last1=Corcoran|first1=M. F. |last2=Rawley|first2=G. L.|last3=Swank|first3=J. H.|last4=Petre|first4=R.|year=1995|doi=10.1086/187904|url=https://cds.cern.ch/record/281359/files/SCAN-9505060.pdf |archive-url=https://ghostarchive.org/archive/20221010/https://cds.cern.ch/record/281359/files/SCAN-9505060.pdf |archive-date=2022-10-10 |url-status=live}}</ref> [[Advanced Satellite for Cosmology and Astrophysics]] (ASCA),<ref name="yohko1997">{{cite journal|bibcode=1997PASJ...49...85T|title=ASCA observations of Eta Carinae |journal=Publications of the Astronomical Society of Japan |volume=49 |pages=85–92 |last1=Tsuboi |first1=Yohko|last2=Koyama|first2=Katsuji |last3=Sakano|first3=Masaaki|last4=Petre |first4=Robert |year=1997 |doi=10.1093/pasj/49.1.85|doi-access=free}}</ref> and [[Chandra X-ray Observatory]]. There are multiple sources at various wavelengths right across the high energy electromagnetic spectrum: hard X-rays and gamma rays within 1&nbsp;light-month of the η&nbsp;Carinae; hard X-rays from a central region about 3&nbsp;light-months wide; a distinct partial ring "horse-shoe" structure in low-energy X-rays 0.67&nbsp;parsec (2.2&nbsp;light-years) across corresponding to the main shockfront from the Great Eruption; diffuse X-ray emission across the whole area of the Homunculus; and numerous condensations and arcs outside the main ring.<ref name="tavani">{{cite journal|bibcode=2009ApJ...698L.142T|title=Detection of gamma-ray emission from the Eta&nbsp;Carinae region |journal=The Astrophysical Journal Letters|volume=698|issue=2|page=L142 |last1=Tavani|first1=M.|last2=Sabatini|first2=S.|last3=Pian|first3=E.|last4=Bulgarelli|first4=A. |last5=Caraveo|first5=P.|last6=Viotti|first6=R.F.|last7=Corcoran|first7=M.F.|last8=Giuliani|first8=A.|last9=Pittori|first9=C.|last10=Verrecchia|first10=F. |last11=Vercellone|first11=S.|last12=Mereghetti|first12=S.|last13=Argan|first13=A.|last14=Barbiellini|first14=G.|last15=Boffelli|first15=F.|last16=Cattaneo|first16=P. W. |last17=Chen|first17=A. W.|last18=Cocco|first18=V.|last19=d'Ammando|first19=F.|last20=Costa|first20=E.|last21=Deparis|first21=G.|last22=Del Monte|first22=E.|last23=Di Cocco |first23=G.|last24=Donnarumma|first24=I.|last25=Evangelista|first25=Y.|last26=Ferrari|first26=A.|last27=Feroci|first27=M.|last28=Fiorini|first28=M.|last29=Froysland|first29=T. |last30=Fuschino|first30=F. |display-authors=6 |year=2009|doi=10.1088/0004-637X/698/2/L142|arxiv = 0904.2736|s2cid=18241474}}</ref><ref name="hard">{{cite journal|bibcode=2008A&A...477L..29L |title=Hard X-ray emission from η Carinae|journal=Astronomy and Astrophysics|volume=477|issue=3|pages=L29|last1=Leyder|first1=J.-C.|last2=Walter|first2=R. |last3=Rauw|first3=G.|year=2008|doi=10.1051/0004-6361:20078981|arxiv = 0712.1491|s2cid=35225132}}</ref><ref name="pittard">{{cite journal|bibcode=2002A&A...383..636P|title=In hot pursuit of the hidden companion of η Carinae: An X-ray determination of the wind parameters|journal=Astronomy and Astrophysics|volume=383|issue=2|pages=636|last1=Pittard|first1=J. M. |last2=Corcoran|first2=M. F.|year=2002|doi=10.1051/0004-6361:20020025|arxiv = astro-ph/0201105 |s2cid=119342823}}</ref><ref name="weis">{{cite journal|bibcode=2001A&A...367..566W|title=High velocity structures in, and the X-ray emission from the LBV nebula around η Carinae|journal=Astronomy and Astrophysics|volume=367|issue=2|pages=566|last1=Weis|first1=K. |last2=Duschl|first2=W. J.|last3=Bomans|first3=D. J.|year=2001|doi=10.1051/0004-6361:20000460|arxiv = astro-ph/0012426|s2cid=16812330}}</ref>

All the high-energy emission associated with η&nbsp;Carinae varies during the orbital cycle. A spectroscopic minimum, or X-ray eclipse, occurred in July and August 2003, and similar events in 2009 and 2014 have been intensively observed.<ref name="xray">{{cite journal |last1=Hamaguchi |first1=K. |last2=Corcoran |first2=M.F. |last3=Gull |first3=T. |last4=Ishibashi |first4=K. |last5=Pittard |first5=J.M. |last6=Hillier |first6=D.J. |last7=Damineli |first7=A. |last8=Davidson |first8=K. |last9=Nielsen |first9=K.E. |last10=Kober |first10=G.V. |display-authors=6 |title=X-Ray Spectral Variation of η Carinae through the 2003 X-Ray Minimum |journal=The Astrophysical Journal |volume=663 |issue=1 |pages=522–542 |year=2007 |bibcode=2007ApJ...663..522H |arxiv=astro-ph/0702409 |s2cid=119341465 |doi=10.1086/518101}}</ref> The highest-energy gamma rays above 100 [[MeV]] detected by [[AGILE (satellite)|AGILE]] show strong variability, while lower-energy gamma rays observed by [[Fermi (satellite)|Fermi]] show little variability.<ref name="tavani"/><ref name="abdo">{{cite journal |last1=Abdo |first1=A.A. |last2=Ackermann |first2=M. |last3=Ajello |first3=M. |last4=Allafort |first4=A. |last5=Baldini |first5=L. |last6=Ballet |first6=J. |last7=Barbiellini |first7=G. |last8=Bastieri |first8=D. |last9=Bechtol |first9=K. |last10=Bellazzini |first10=R. |last11=Berenji |first11=B. |last12=Blandford |first12=R.D. |last13=Bonamente |first13=E. |last14=Borgland |first14=A.W. |last15=Bouvier |first15=A. |last16=Brandt |first16=T.J. |last17=Bregeon |first17=J. |last18=Brez |first18=A. |last19=Brigida |first19=M. |last20=Bruel |first20=P. |last21=Buehler |first21=R. |last22=Burnett |first22=T.H. |last23=Caliandro |first23=G.A. |last24=Cameron |first24=R.A. |last25=Caraveo |first25=P.A. |last26=Carrigan |first26=S. |last27=Casandjian |first27=J.M. |last28=Cecchi |first28=C. |last29=Çelik |first29=Ö. |last30=Chaty |first30=S. |display-authors=6 |year=2010 |title=Fermi Large Area Telescope observation of a gamma-ray source at the position of Eta Carinae |journal=The Astrophysical Journal |volume=723 |issue=1 |pages=649–657 |bibcode=2010ApJ...723..649A |arxiv=1008.3235 |s2cid=51412901 |doi=10.1088/0004-637X/723/1/649 }}</ref>