{{Short description|Seyfert 1 galaxy in the constellation Boötes}} {{Infobox galaxy|name=[[Markarian galaxies|Markarian]] 478|epoch=[[J2000.0]]|constellation name=[[Boötes]]|ra={{RA|14|42|07.47}}<ref name="ned" />|dec={{DEC|+35|26|22.95}}<ref name="ned" />|z=0.079055<ref name="ned" />|h_radial_v=23,700 [[kilometer per second|km/s]]<ref name="ned" />|dist_ly=1.08 [[light years|Gly]]|appmag_v=14.58|type=Spiral Sy1<ref name="ned" />|size=~{{convert|42.1|kpc|ly|abbr=on|lk=on|order=flip}} (estimated){{r|ned}}|names=PG 1440+356, [[IRAS]] 14400+3539, [[Principal Galaxies Catalogue|PGC]] 52510, CG 0512, RBS 1418, [[ROSAT|RX]] J1442.1+3526, [[NRAO VLA Sky Survey|NVSS]] J144207+352624<ref name="ned" />|image=File:Image of Markarian 478.png|caption=[[Sloan Digital Sky Survey|SDSS]] image of Seyfert galaxy Markarian 478}}
'''Markarian 478''' also known as '''MRK 478''', is a [[Seyfert galaxy|Seyfert 1 galaxy]]<ref>{{Cite journal |last1=Gondhalekar |first1=P. M. |last2=Kellett |first2=B. J. |last3=Pounds |first3=K. A. |last4=Matthews |first4=L. |last5=Quenby |first5=J. J. |date=June 1994 |title=ROSAT/XRT-PSPC observations and the ionizing continuum of Seyfert 1 galaxy MKN 478 |journal=Monthly Notices of the Royal Astronomical Society |language=en |volume=268 |issue=4 |pages=973–983 |doi=10.1093/mnras/268.4.973 |bibcode=1994MNRAS.268..973G |doi-access=free |issn=0035-8711}}</ref> located in the constellation of [[Boötes]]. The redshift of the galaxy is (z) 0.079,<ref name="ned">{{Cite web |title=NED search results for Markarian 478 |url=https://ned.ipac.caltech.edu/byname?objname=Markarian+478&hconst=67.8&omegam=0.308&omegav=0.692&wmap=4&corr_z=1 |access-date=2025-08-10 |website=NASA/IPAC Extragalactic Database}}</ref> giving it a distance of about 1 billion light-years from Earth. It was first discovered in 1974 by astronomers from [[Arecibo Observatory]] via a 1000-foot radio [[telescope]].<ref>{{Cite journal |last1=Tovmassian |first1=H. M. |last2=Terzian |first2=Y. |date=October 1974 |title=Radio Emission from Some Markarian Galaxies at 430 MHz |url=https://articles.adsabs.harvard.edu/pdf/1974PASP...86..649T |journal=Publications of the Astronomical Society of the Pacific |language=en |volume=86 |issue=513 |pages=649 |doi=10.1086/129658 |bibcode=1974PASP...86..649T |issn=0004-6280}}</ref> It displays doubly ionized [[iron]] [[Spectral line|emission lines]] in its spectrum and is classified as a radio-quiet [[quasar]].<ref>{{Cite journal |last1=Rudy |first1=Richard J. |last2=Lynch |first2=David K. |last3=Mazuk |first3=S. |last4=Venturini |first4=Catherine C. |last5=Puetter |first5=R. C. |last6=Hamann |first6=F. |date=August 2001 |title=Markarian 478: A Second Seyfert Galaxy with 1 Micron Fe II Emission Lines |url=https://iopscience.iop.org/article/10.1086/322914/pdf |journal=Publications of the Astronomical Society of the Pacific |language=en |volume=113 |issue=786 |pages=916–919 |doi=10.1086/322914 |bibcode=2001PASP..113..916R |issn=0004-6280}}</ref><ref name=":0">{{Cite journal |last1=Dunlop |first1=J. S. |last2=Taylor |first2=G. L. |last3=Hughes |first3=D. H. |last4=Robson |first4=E. I. |date=September 1993 |title=Infrared imaging of the host galaxies of radio-loud and radio-quiet quasars. |journal=Monthly Notices of the Royal Astronomical Society |language=en |volume=264 |issue=2 |pages=455–488 |doi=10.1093/mnras/264.2.455 |bibcode=1993MNRAS.264..455D |doi-access=free |issn=0035-8711}}</ref>
== Description == Markarian 478 is specifically described as a prototype narrow-line Seyfert galaxy. It displays emission lines that are increasing in [[flux]] levels in blue wing components with increasing line peaks in [[velocity]] shifts. The spectrum of this galaxy also shows the presence of [[Absorption spectroscopy|absorption lines]] on the blue wing components of emission doublets and [[Lyman series|Lyman]] [[Beta|β]] lines. Observations also found the high-[[ionization]] emission lines have high velocities at blueshifts suggesting outflowing gas is mainly produced in its [[Active galactic nucleus|broad-line region]].<ref>{{Cite journal |last1=Yuan |first1=Q. |last2=Brotherton |first2=M. |last3=Green |first3=R. F. |last4=Kriss |first4=G. A. |date=June 2004 |title=Outflowing Components in the Prototype Narrow-Line Seyfert 1 Galaxy Markarian 478 |url=https://articles.adsabs.harvard.edu/pdf/2004IAUS..217..364Y |journal=Recycling Intergalactic and Interstellar Matter |language=en |volume=217 |pages=364 |bibcode=2004IAUS..217..364Y |issn=1743-9221}}</ref>
The host of Markarian 478 is a round [[spiral galaxy]] with two undisturbed asymmetric and visible [[Spiral arm|spiral arms]].<ref name=":0" /><ref>{{Cite journal |last1=Guyon |first1=O. |last2=Sanders |first2=D. B. |last3=Stockton |first3=Alan |date=September 2006 |title=Near-Infrared Adaptive Optics Imaging of QSO Host Galaxies |url=https://iopscience.iop.org/article/10.1086/505030/fulltext/ |journal=The Astrophysical Journal Supplement Series |volume=166 |issue=1 |pages=89–127 |doi=10.1086/505030 |arxiv=astro-ph/0605079 |bibcode=2006ApJS..166...89G |issn=0067-0049}}</ref> Its nucleus is elongated northeast to southeast, with its main body also being elongated perpendicular to it. Evidence also showed there are faint shells or arms in the host implying a clear disturbed morphology.<ref>{{Cite journal |last1=Surace |first1=Jason A. |last2=Sanders |first2=D. B. |last3=Evans |first3=A. S. |date=December 2001 |title=Optical and Near-Infrared Imaging of Infrared-Excess Palomar-Green Quasars |journal=The Astronomical Journal |language=en |volume=122 |issue=6 |pages=2791–2809 |doi=10.1086/324462 |arxiv=astro-ph/0109405 |bibcode=2001AJ....122.2791S |issn=0004-6256}}</ref><ref>{{Cite web |title=Markarian 478 |url=http://quasar.square7.ch/fqm/1440+356.html |access-date=2025-08-10 |website=Frankfurt Quasar Monitoring}}</ref> A 3.3-ɥm PAH emission feature was detected in the galaxy.<ref>{{Cite journal |last1=Rodriguez-Ardila |first1=A. |last2=Viegas |first2=S. M. |date=2003-04-21 |title=Hidden starbursts in Seyfert 1 galaxies |journal=Monthly Notices of the Royal Astronomical Society |volume=340 |issue=4 |pages=L33–L37 |doi=10.1046/j.1365-8711.2003.06538.x |arxiv=astro-ph/0302327 |bibcode=2003MNRAS.340L..33R |doi-access=free |issn=0035-8711}}</ref>
Markarian 478 is variable. Based on its EUV (Extreme [[Ultraviolet]] Emission) [[light curve]], most of the flux variations occurred in the lines and not in continuum. The [[amplitude]] variations are described as highly significant, occurring on a factor of three on a timescale less than one day.<ref>{{Cite journal |last1=Hwang |first1=Chorng-Yuan |last2=Bowyer |first2=Stuart |date=February 1997 |title=The Extreme-Ultraviolet Emission of the Seyfert Galaxies Markarian 279, Markarian 478, and Ton S180 |url=https://iopscience.iop.org/article/10.1086/303562/fulltext/ |journal=The Astrophysical Journal |volume=475 |issue=2 |pages=552–556 |doi=10.1086/303562 |bibcode=1997ApJ...475..552H |issn=0004-637X}}</ref>
The [[X-ray spectroscopy|X-ray spectrum]] of Markarian 478 is soft and steep.<ref>{{Cite journal |last1=Marshall |first1=H. L. |last2=Carone |first2=T. E. |last3=Shull |first3=J. Michael |last4=Malkan |first4=M. A. |last5=Elvis |first5=M. |date=January 1996 |title=The Steep Soft X-Ray Spectrum of the Highly Variable Active Nucleus in Markarian 478 |url=https://ui.adsabs.harvard.edu/abs/1996ApJ...457..169M/abstract |journal=The Astrophysical Journal |language=en |volume=457 |pages=169 |doi=10.1086/176720 |bibcode=1996ApJ...457..169M |issn=0004-637X}}</ref> It is also mainly dominated by soft excess with some traces of excess residuals in the 5-7 [[Electronvolt|KeV]] band.<ref>{{Cite journal |last1=Waddell |first1=S G H |last2=Gallo |first2=L C |last3=Gonzalez |first3=A G |last4=Tripathi |first4=S |last5=Zoghbi |first5=A |date=2019-09-10 |title=Multi-epoch X-ray spectral analysis of the narrow-line Seyfert 1 galaxy Mrk 478 |journal=Monthly Notices of the Royal Astronomical Society |volume=489 |issue=4 |pages=5398–5412 |doi=10.1093/mnras/stz2518 |doi-access=free |issn=0035-8711|arxiv=1909.01897 }}</ref> Based on observation results using data from Swift, [[XMM-Newton]] and [[AstroSat]], it is shown to have both long-term and intermediate-term variability. Evidence also showed the [[Reflection (physics)|reflection]] fraction is anticorrelated, with the [[spectral index]] and flux suggesting the variability was caused by hard X-rays that were producing a corona moving closer and away from its central [[black hole]].<ref>{{Cite journal |last1=Barua |first1=Samuzal |last2=Jithesh |first2=V |last3=Misra |first3=Ranjeev |last4=Medhi |first4=Biman J |last5=Adegoke |first5=Oluwashina |date=2022-09-23 |title=Correlated variability of the reflection fraction with the X-ray flux and spectral index for Mrk 478 |journal=Monthly Notices of the Royal Astronomical Society |volume=517 |issue=1 |pages=801–807 |doi=10.1093/mnras/stac2690 |doi-access=free |issn=0035-8711}}</ref> The mass of the black hole in Markarian 478 is estimated to be 7.30 M<sub>☉</sub>.<ref>{{Cite journal |last1=Kawakatu |first1=Nozomu |last2=Imanishi |first2=Masatoshi |last3=Nagao |first3=Tohru |date=June 2007 |title=Anticorrelation between the Mass of a Supermassive Black Hole and the Mass Accretion Rate in Type 1 Ultraluminous Infrared Galaxies and Nearby QSOs |journal=The Astrophysical Journal |language=en |volume=661 |issue=2 |pages=660–671 |doi=10.1086/516563 |arxiv=astro-ph/0702552 |bibcode=2007ApJ...661..660K |issn=0004-637X}}</ref>
== References == <references />
{{Boötes}}
{{DEFAULTSORT:Markarian 478}} [[Category:Seyfert galaxies]] [[Category:Boötes]] [[Category:Active galaxies]] [[Category:Quasars]] [[Category:Principal Galaxies Catalogue objects|052510]] [[Category:Markarian galaxies]] [[Category:Spiral galaxies]] [[Category:Astronomical objects discovered in 1974]]