{{Short description|BL Lacertae object in the constellation Draco}} {{Infobox galaxy|name=S5 2007+777|epoch=[[J2000.0]]|constellation name=[[Draco (constellation)|Draco]]|ra={{RA|20|05|30.998}}|dec={{DEC|+77|52|43.248}}|z=0.342000|h_radial_v=102,529 [[kilometer per second|km/s]]|dist_ly=3.662 [[light years|Gly]]|appmag_v=16.5|type=BL Lac|notes=Core-dominated source, HYMORS, one of the four [[BL Lacertae]] objects displaying an extended kiloparsec-scale X-ray jet|names=S5 2007+77, [[NRAO VLA Sky Survey|NVSS]] J200531+775243, [[Sixth Cambridge Survey of Radio Sources|6C]] 200718+774350, 4FGL J2005.5+7752, 2E 4325, WMAP J2005+7755, 1RXS J200529.2+775240|image=File:Image of S5 2007+777.jpg|caption=The BL Lacertae object S5 2007+777.}}

'''S5 2007+777''' is a classical [[BL Lacertae object]]<ref>{{Cite journal |last1=Li |first1=Z. X. |last2=Wu |first2=Z. Z. |last3=Chen |first3=Y. J. |last4=Chen |first4=L. |last5=Gu |first5=M. F. |last6=Mi |first6=L. G. |date=2019-05-01 |title=The Radio Properties for BL Lac Object S5 2007+777 |url=https://ui.adsabs.harvard.edu/abs/2019AcASn..60...20L/abstract |journal=Acta Astronomica Sinica |volume=60 |issue=3 |pages=20 |bibcode=2019AcASn..60...20L |issn=0001-5245}}</ref> located in the [[constellation]] of [[Draco (constellation)|Draco]]. This object has a [[redshift]] of (z) 0.342<ref>{{Cite journal |last1=Peng |first1=B. |last2=Kraus |first2=A. |last3=Krichbaum |first3=T. P. |last4=Witzel |first4=A. |date=July 2000 |title=Long-term monitoring of selected radio sources |url=https://aas.aanda.org/articles/aas/pdf/2000/13/ds1843.pdf |journal=Astronomy and Astrophysics Supplement Series |volume=145 |issue=1 |pages=1–10 |doi=10.1051/aas:2000230 |bibcode=2000A&AS..145....1P |issn=0365-0138}}</ref> and was first discovered in 1981 as a [[flat-spectrum radio quasar]].<ref>{{Cite journal |last1=Biermann |first1=P. |last2=Duerbeck |first2=H. |last3=Eckart |first3=A. |last4=Fricke |first4=K. |last5=Johnston |first5=K. J. |last6=Kuhr |first6=H. |last7=Liebert |first7=J. |last8=Pauliny-Toth |first8=I. I. K. |last9=Schleicher |first9=H. |last10=Stockman |first10=H. |last11=Strittmatter |first11=P. A. |last12=Witzel |first12=A. |date=July 1981 |title=Observations of six flat spectrum sources from the 5 GHz survey |url=https://articles.adsabs.harvard.edu/pdf/1981ApJ...247L..53B |journal=The Astrophysical Journal |volume=247 |pages=L53 |doi=10.1086/183588 |bibcode=1981ApJ...247L..53B |issn=0004-637X}}</ref> It has characteristics of different [[Fanaroff–Riley classification|Fanaroff-Riley]] classes on both sides of its [[Active galactic nucleus|active nucleus]] making it a rare type of Hybrid morphology radio sources (HYMORs).<ref name=":0">{{Cite journal |last1=Sambruna |first1=Rita M. |last2=Donato |first2=Davide |last3=Cheung |first3=C. C. |last4=Tavecchio |first4=F. |last5=Maraschi |first5=L. |date=2008-09-10 |title=A Kiloparsec-Scale X-Ray Jet in the BL Lac Source S5 2007+777 |url=https://iopscience.iop.org/article/10.1086/589918/fulltext/ |journal=The Astrophysical Journal |volume=684 |issue=2 |pages=862–869 |doi=10.1086/589918 |bibcode=2008ApJ...684..862S |issn=0004-637X}}</ref> It has an estimated [[Apparent magnitude|V magnitude]] of 16.5.<ref>{{Cite journal |last1=Ros |first1=E. |last2=Marcaide |first2=J. M. |last3=Guirado |first3=J. C. |last4=Ratner |first4=M. I. |last5=Shapiro |first5=I. I. |last6=Krichbaum |first6=T. P. |last7=Witzel |first7=A. |last8=Preston |first8=R. A. |date=1999-08-01 |title=High precision difference astrometry applied to the triplet of S5 radio sources B1803+784/Q1928+738/B2007+777 |url=https://articles.adsabs.harvard.edu/pdf/1999A%26A...348..381R |journal=Astronomy and Astrophysics |volume=348 |pages=381–393 |arxiv=astro-ph/9905265 |bibcode=1999A&A...348..381R |issn=0004-6361}}</ref>

== Description == S5 2007+777 is classified as a [[blazar]]<ref>{{Cite journal |last=Nesci |first=Roberto |date=2016-02-01 |title=Optical follow-up of the blazar S5 2007+77 |url=https://ui.adsabs.harvard.edu/abs/2016ATel.8642....1N/abstract |journal=The Astronomer's Telegram |volume=8642 |pages=1|bibcode=2016ATel.8642....1N }}</ref><ref>{{Cite journal |last1=Carrasco |first1=L. |last2=Miramon |first2=J. |last3=Porras |first3=A. |last4=Recillas |first4=E. |last5=Chavushyan |first5=V. |last6=Carraminana |first6=A. |date=2015-10-01 |title=NIR brightening of the Quasar HB89 2007+777 |url=https://ui.adsabs.harvard.edu/abs/2015ATel.8187....1C/abstract |journal=The Astronomer's Telegram |volume=8187 |pages=1|bibcode=2015ATel.8187....1C }}</ref> showing variability across the [[electromagnetic spectrum]] with [[amplitude]]s rising steadily along with [[frequency]].<ref>{{Cite journal |last1=Kraus |first1=A. |last2=Krichbaum |first2=T. P. |last3=Wegner |first3=R. |last4=Witzel |first4=A. |last5=Cimò |first5=G. |last6=Quirrenbach |first6=A. |last7=Britzen |first7=S. |last8=Fuhrmann |first8=L. |last9=Lobanov |first9=A. P. |last10=Naundorf |first10=C. E. |last11=Otterbein |first11=K. |last12=Peng |first12=B. |last13=Risse |first13=M. |last14=Ros |first14=E. |last15=Zensus |first15=J. A. |date=2003-03-17 |title=Intraday variability in compact extragalactic radio sources II. Observations with the Effelsberg 100 m radio telescope |url=https://www.aanda.org/articles/aa/pdf/2003/13/aah3992.pdf |journal=Astronomy & Astrophysics |volume=401 |issue=1 |pages=161–172 |doi=10.1051/0004-6361:20030118 |bibcode=2003A&A...401..161K |issn=0004-6361}}</ref> It is also an Intraday Variable (IDV) source exhibiting variations as a whole as well as in [[Polarization (cosmology)|polarized]] intensity on [[Time-scale calculus|time scales]] ranging from 2 to 6 days at [[Centimetre|centimeter]] (cm) [[wavelength]]s.<ref>{{Cite journal |last1=Gabanyi |first1=K.E. |last2=Krichbaum |first2=T.P. |last3=Kraus |first3=A. |last4=Witzel |first4=A. |last5=Zensus |first5=J.A. |date=2009 |title=VSOP Observations of the Blazar S5 2007+77 |url=https://adsabs.harvard.edu/full/2009ASPC..402..155G |journal=Approaching Micro-Arcsecond Resolution with VSOP-2: Astrophysics and Technologies ASP Conference Series |volume=402 |pages=155|arxiv=0802.0540 |bibcode=2009ASPC..402..155G }}</ref> In dereddened B and [[I band (infrared)|I-band]] [[light curve]]s during observations conducted in 2001, S5 2007+777 shows a smaller amplitude variation of 10%. Subsequent observations conducted in both 2002 and 2004, shows the object having minimum to maximum variations of order 30-40% on 2-4 day time scales.<ref>{{Cite journal |last1=Xilouris |first1=E. M. |last2=Papadakis |first2=I. E. |last3=Boumis |first3=P. |last4=Dapergolas |first4=A. |last5=Alikakos |first5=J. |last6=Papamastorakis |first6=J. |last7=Smith |first7=N. |last8=Goudis |first8=C. D. |date=2006-02-17 |title=''B'' and ''I''-band optical micro-variability observations of the BL Lac objects S5 2007+777 and 3C 371 |journal=Astronomy & Astrophysics |volume=448 |issue=1 |pages=143–153 |doi=10.1051/0004-6361:20054054 |arxiv=astro-ph/0511130 |bibcode=2006A&A...448..143X |issn=0004-6361}}</ref>

Although mostly in a quiescent state, one outburst was detected in S5 2007+777 between 1991 and 1992 with the peak flux of this source reaching 3.69 [[Jansky]] at 14.5 [[Hertz|GHz]].<ref>{{Cite journal |last1=Nieppola |first1=Elina |last2=Hovatta |first2=Talvikki |last3=Tornikoski |first3=Merja |last4=Valtaoja |first4=Esko |last5=Aller |first5=Margo F. |last6=Aller |first6=Hugh D. |date=2009-05-06 |title=Long-Term Variability of Radio-Bright Bl Lacertae Objects |url=https://iopscience.iop.org/article/10.1088/0004-6256/137/6/5022/pdf |journal=The Astronomical Journal |volume=137 |issue=6 |pages=5022–5036 |doi=10.1088/0004-6256/137/6/5022 |issn=0004-6256|arxiv=0910.2607 |bibcode=2009AJ....137.5022N }}</ref> A [[gamma ray]] flare was detected in February 2016 during an observation from the Foligno Observatory via a 30&nbsp;cm [[telescope]].<ref>{{Cite journal |last=Nesci |first=Roberto |date=2016-02-01 |title=Optical follow-up of the blazar S5 2007+77 |url=https://ui.adsabs.harvard.edu/abs/2016ATel.8642....1N/abstract |journal=The Astronomer's Telegram |volume=8642 |pages=1|bibcode=2016ATel.8642....1N }}</ref>

According to [[radio imaging]] of S5 2007+777 made by [[Very Long Baseline Array]], a one-sided core-jet structure is found with one of the components exhibiting [[proper motion]] and greater flux density.<ref>{{Cite journal |last1=Pérez-Torres |first1=M. A. |last2=Marcaide |first2=J. M. |last3=Guirado |first3=J. C. |last4=Ros |first4=E. |date=December 2004 |title=Absolute kinematics of radio source components in the complete S5 polar cap sample II. First and second epoch maps at 15 GHz |url=https://www.aanda.org/articles/aa/pdf/2004/48/aa0423-04.pdf |journal=Astronomy & Astrophysics |volume=428 |issue=3 |pages=847–866 |doi=10.1051/0004-6361:20040423 |arxiv=astro-ph/0408581 |bibcode=2004A&A...428..847P |hdl=10550/13998 |issn=0004-6361}}</ref> Imaging by [[Very Large Array]] and [[Very-long-baseline interferometry|Very Long Baseline Interferometry]], shows the object as a core-dominated source instead, consisting of a bright [[Radio galaxy|radio lobe]] on the eastern side and a long [[Astrophysical jet|jet]] on the western side of the nucleus which terminates without a clear hot spot upon reaching at 10 [[Minute and second of arc|arcseconds]] from the nucleus.<ref name=":0" /><ref>{{Cite journal |last1=Gopal-Krishna |last2=Wiita |first2=Paul J. |date=May 2002 |title=Hybrid morphology radio sources and the Fanaroff–Riley dichotomy |url=https://articles.adsabs.harvard.edu//full/2000A%26A...363..507G/0000512.000.html |journal=Astronomy & Astrophysics |volume=46 |issue=2–7 |pages=357–360 |doi=10.1016/s1387-6473(01)00208-1 |arxiv=astro-ph/0009441 |bibcode=2000A&A...363..507G |issn=1387-6473}}</ref> This jet is known to show [[superluminal motion]], being aligned 24° to the [[line of sight]] with its 4.9&nbsp;GHz luminosity calculated to be 10<sup>32</sup> [[erg]] s<sup>−1</sup> Hz<sup>−1</sup>.<ref name=":0" />

The radio emission of the jet in S5 2007+777 shows several unique radio knots with the brightest one located midstream. The jet itself imaged at 1.49&nbsp;GHz, has an extended structure in linear direction which it bends west at a changed [[position angle]] of 20°.<ref name=":0" /> An extended [[X-ray astronomy|X-ray]] jet was also found by [[Chandra X-ray Observatory|Chandra]] on [[Parsec|kiloparsec]]-scales, making S5 2007+777 only one of the four BL Lacertae objects to have this feature.<ref>{{Cite journal |last1=Wu |first1=ZhongZu |last2=Gu |first2=MinFeng |last3=Chen |first3=YongJun |date=2010-01-01 |title=The radio structure of BL Lac object S5 2007+777 |url=https://link.springer.com/article/10.1007/s11433-010-0056-7 |journal=Science China Physics, Mechanics and Astronomy |language=en |volume=53 |issue=1 |pages=187–190 |doi=10.1007/s11433-010-0056-7 |bibcode=2010SCPMA..53S.187W |issn=1862-2844|url-access=subscription }}</ref><ref>{{Cite journal |last1=Sambruna |first1=R. M. |last2=Donato |first2=D. |last3=Cheung |first3=C. C. Tavecchio, F. |last4=Maraschi |first4=L. |date=2008-06-01 |title=An X-ray Jet in the BL Lac S5 2007+777 |url=https://articles.adsabs.harvard.edu/pdf/2008ASPC..386...94S |journal=Extragalactic Jets: Theory and Observation from Radio to Gamma Ray ASP Conference Series |volume=386 |pages=94 |arxiv=0707.1321 |bibcode=2008ASPC..386...94S }}</ref>

== References == <references />

== External links == *[https://simbad.u-strasbg.fr/simbad/sim-id?Ident=8C%202007%2B777 S5 2007+777 on SIMBAD] *[https://ned.ipac.caltech.edu/cgi-bin/objsearch?search_type=Obj_id&objid=64311&objname=1&img_stamp=YES&hconst=73.0&omegam=0.27&omegav=0.73&corr_z=1 S5 2007+777 on NASA/IPAC Database]

{{Draco (constellation)}}

[[Category:BL Lacertae objects]] [[Category:Draco (constellation)]] [[Category:Blazars]] [[Category:Quasars]] [[Category:Active galaxies]] [[Category:Astronomical objects discovered in 1981]]