{{Short description|BL Lac object located in the constellation Boötes}} {{Infobox galaxy|name=H1426+428|epoch=[[J2000.0]]|constellation name=[[Boötes]]|ra={{RA|14|28|32.60}}|dec={{DEC|+42|40|20.97}}|z=0.129265|h_radial_v=38,753 [[kilometer per second|km/s]]|dist_ly=1.911 [[light years|Gly]] (585.91 [[Megaparsec|Mpc]])|appmag_v=16.45|appmag_b=16.95|type=BL LAC|names=1ES 1426+428, [[Lyon-Meudon Extragalactic Database|LEDA]] 2203750, 4FGL J1428.5+4240, 1ES 1426+42.8, TeV J1428+426, 1RXS J142832.6+424028, [[ROSAT|RX]] J1428.5+4240|image=File:Image of H1426+428.jpg|caption=The BL Lac object H1426+428.}}
'''H1426+428''' also known as '''1ES 1426+428''', is a high-frequency peaked [[BL Lacertae object]] (HBL)<ref>{{cite journal |doi=10.1051/0004-6361/201833621 |doi-access=free |title=Long-term optical monitoring of TeV emitting blazars |date=2018 |last1=Nilsson |first1=K. |last2=Lindfors |first2=E. |last3=Takalo |first3=L. O. |last4=Reinthal |first4=R. |last5=Berdyugin |first5=A. |last6=Sillanpää |first6=A. |last7=Ciprini |first7=S. |last8=Halkola |first8=A. |last9=Heinämäki |first9=P. |last10=Hovatta |first10=T. |last11=Kadenius |first11=V. |last12=Nurmi |first12=P. |last13=Ostorero |first13=L. |last14=Pasanen |first14=M. |last15=Rekola |first15=R. |last16=Saarinen |first16=J. |last17=Sainio |first17=J. |last18=Tuominen |first18=T. |last19=Villforth |first19=C. |last20=Vornanen |first20=T. |last21=Zaprudin |first21=B. |journal=Astronomy & Astrophysics |volume=620 |pages=A185 |arxiv=1810.01751 }}</ref><ref>{{Cite journal |last1=Mueller |first1=C. |last2=Akhter |first2=N. |last3=Ball |first3=J. |last4=Bramel |first4=D.A. |last5=Carson |first5=J. |last6=Covault |first6=C.E. |last7=Driscoll |first7=D. |last8=Fortin |first8=P. |last9=Gingrich |first9=D.M. |last10=Hanna |first10=D.S. |last11=Jarvis |first11=A. |last12=Kildea |first12=J. |last13=Lindner |first13=T. |last14=Mukherjee |first14=R. |last15=Ong |first15=R.A. |date=April 2011 |title=Very high-energy observations of the two high-frequency peaked BL Lac objects 1ES 1218+304 and H 1426+428 |url=http://dx.doi.org/10.1016/j.astropartphys.2011.01.010 |journal=Astroparticle Physics |volume=34 |issue=9 |pages=674–678 |doi=10.1016/j.astropartphys.2011.01.010 |arxiv=1104.2770 |bibcode=2011APh....34..674M |issn=0927-6505}}</ref> located in the [[constellation]] of [[Boötes]]. It is located at a relatively high<ref>{{Cite journal |last1=Fan |first1=Y. Z. |last2=Dai |first2=Z. G. |last3=Wei |first3=D. M. |date=February 2004 |title=Strong GeV emission accompanying TeV blazar H1426+428 |url=https://www.aanda.org/articles/aa/pdf/2004/08/aa0472.pdf |journal=Astronomy & Astrophysics |volume=415 |issue=2 |pages=483–486 |doi=10.1051/0004-6361:20034472 |arxiv=astro-ph/0310893 |bibcode=2004A&A...415..483F |issn=0004-6361}}</ref> [[redshift]] of (z) 0.129,<ref>{{Cite journal |last=Horan and the VERITAS Collaboration |first=D. |date=2001 |title=Observations of the BL Lac object, 1H1426+428 at TeV gamma-ray energies |url=http://dx.doi.org/10.1063/1.1419423 |journal=AIP Conference Proceedings |publisher=AIP |volume=587 |pages=324–328 |doi=10.1063/1.1419423|bibcode=2001AIPC..587..324H |url-access=subscription }}</ref> and was discovered in 1984 by [[astronomer]]s who presented a catalogue of X-ray sources taken with the [[High Energy Astronomy Observatory 1|HEAO 1 satellite]].<ref>{{Cite journal |last1=Nugent |first1=J. J. |last2=Jensen |first2=K. A. |last3=Nousek |first3=J. A. |last4=Garmire |first4=G. P. |last5=Mason |first5=K. O. |last6=Walter |first6=F. M. |last7=Bowyer |first7=C. S. |last8=Stern |first8=R. A. |last9=Riegler |first9=G. R. |date=January 1983 |title=HEAO A-2 soft X-ray source catalog |url=https://articles.adsabs.harvard.edu/pdf/1984ApJS...56..507W |journal=The Astrophysical Journal Supplement Series |volume=51 |pages=1 |doi=10.1086/190838 |bibcode=1983ApJS...51....1N |issn=0067-0049}}</ref>
H1426+428 is classified as a [[blazar]].<ref name=":0">{{Cite web |last1=Nowakowski |first1=Tomasz |last2=Phys.org |title=Observers detect intraday variability of blazar 1ES 1426+42.8 |url=https://phys.org/news/2024-09-intraday-variability-blazar-1es.html |access-date=2024-10-21 |website=phys.org |language=en}}</ref> It is also a distant source of [[TeV]] [[gamma ray]]s.<ref>{{Cite journal |last1=Horan |first1=D. |last2=Bond |first2=I. H. |last3=Boyle |first3=P. J. |last4=Bradbury |first4=S. M. |last5=Buckley |first5=J. H. |last6=Carter-Lewis |first6=D. |last7=Celik |first7=O. |last8=Cui |first8=W. |last9=Daniel |first9=M. |last10=D'Vali |first10=M. |last11=de la Calle Perez |first11=I. |last12=Duke |first12=C. |last13=Falcone |first13=A. |last14=Fegan |first14=D. J. |last15=Fegan |first15=S. J. |date=2003-07-01 |title=Observations of H1426+428 from 1999 to 2002 with the Whipple Observatory 10 m Telescope |journal=International Cosmic Ray Conference |url=https://ui.adsabs.harvard.edu/abs/2003ICRC....5.2647H/abstract |volume=5 |pages=2647 |arxiv=astro-ph/0305579 |bibcode=2003ICRC....5.2647H }}</ref><ref name=":1">{{Cite journal |last1=Aharonian |first1=F. |last2=Akhperjanian |first2=A. |last3=Barrio |first3=J. |last4=Beilicke |first4=M. |last5=Bernlöhr |first5=K. |last6=Börst |first6=H. |last7=Bojahr |first7=H. |last8=Bolz |first8=O. |last9=Contreras |first9=J. |last10=Cornils |first10=R. |last11=Cortina |first11=J. |last12=Denninghoff |first12=S. |last13=Fonseca |first13=V. |last14=Girma |first14=M. |last15=Gonzalez |first15=J. |date=2002-03-01 |title=TeV gamma rays from the blazar H 1426+428 and the diffuse extragalactic background radiation |url=https://www.aanda.org/articles/aa/abs/2002/12/aadi211/aadi211.html |journal=Astronomy & Astrophysics |language=en |volume=384 |issue=3 |pages=L23–L26 |doi=10.1051/0004-6361:20020206 |bibcode=2002A&A...384L..23A |issn=0004-6361|arxiv=astro-ph/0202072 }}</ref> It has low power and a [[Synchrotron radiation|synchrotron]] peak that is above 100 [[Electronvolt|KeV]].<ref name=":0" /><ref>{{Cite journal |last1=Chang |first1=X |last2=Xiong |first2=D R |last3=Yi |first3=T F |last4=Liu |first4=C X |last5=Bhatta |first5=G |last6=Xu |first6=J R |last7=Gong |first7=Y L |date=2024-08-07 |title=Optical intraday variability analysis for the BL Lacertae object 1ES 1426+42.8 |journal=Monthly Notices of the Royal Astronomical Society |volume=533 |issue=1 |pages=120–130 |doi=10.1093/mnras/stae1839 |doi-access=free |issn=0035-8711|arxiv=2409.06983 }}</ref> Furthermore, H1426+428 is possibly hosted in an [[elliptical galaxy]] and is luminous in [[X-ray]] bands. It has a 2-6 keV luminosity of ~10<sup>44</sup> erg s<sup>−1</sup>.<ref>{{Cite journal |last1=Horan |first1=D. |last2=Badran |first2=H.M. |last3=Bond |first3=I.H. |last4=Bradbury |first4=S.M. |last5=Buckley |first5=J.H. |last6=Carson |first6=M.J. |last7=Carter-Lewis |first7=D.A. |last8=Catanese |first8=M. |last9=Cui |first9=W. |last10=Dunlea |first10=S. |last11=Das |first11=D. |last12=Calle Perez |first12=I. de la |last13=D'Vali |first13=M. |date=June 2002 |title=Detection of the BL Lacertae Object H1426+428 at TeV Gamma-Ray Energies |url=https://iopscience.iop.org/article/10.1086/340019/fulltext/ |journal=The Astrophysical Journal |volume=571 |issue=2 |pages=753–762|doi=10.1086/340019 |arxiv=astro-ph/0202185 |bibcode=2002ApJ...571..753H }}</ref>
The gamma emission in H1426+428 is found to have an average [[flux]]. Its spectrum is very steep and shows a differential [[spectral index]] of γ = -3.60 ± 0.57, when observed by the [[Cosmic Anisotropy Telescope]] (CAT) in Very High energy gamma ray bands between 1998 and 2000.<ref name=":2">{{Cite journal |last1=Djannati-Ataï |first1=A. |last2=Khelifi |first2=B. |last3=Vorobiov |first3=S. |last4=Bazer-Bachi |first4=R. |last5=Chounet |first5=L. M. |last6=Debiais |first6=G. |last7=Degrange |first7=B. |last8=Espigat |first8=P. |last9=Fabre |first9=B. |last10=Fontaine |first10=G. |last11=Goret |first11=P. |last12=Gouiffes |first12=C. |last13=Masterson |first13=C. |last14=Piron |first14=F. |last15=Punch |first15=M. |date=2002-08-09 |title=Detection of the BL Lac object 1ES 1426+428 in the Very High Energy gamma-ray band by the CAT Telescope from 1998–2000 |url=https://www.aanda.org/articles/aa/pdf/2002/33/aaef182.pdf |journal=Astronomy & Astrophysics |volume=391 |issue=3 |pages=L25–L28 |doi=10.1051/0004-6361:20021034 |arxiv=astro-ph/0207618 |bibcode=2002A&A...391L..25D |issn=0004-6361}}</ref> This steep spectrum is mainly contributed by the absorption of gamma rays in the [[Warm–hot intergalactic medium|intergalactic medium]]<ref>{{Cite journal |last1=Petry |first1=D. |last2=Bond |first2=I.H. |last3=Bradbury |first3=S.M. |last4=Buckley |first4=J.H. |last5=Carter-Lewis |first5=D.A. |last6=Cui |first6=W. |date=November 2002 |title=The TeV Spectrum of H1426+428 |url=https://iopscience.iop.org/article/10.1086/343102/fulltext/ |journal=The Astrophysical Journal |volume=580 |issue=1 |pages=104–109 |doi=10.1086/343102|arxiv=astro-ph/0207506 |bibcode=2002ApJ...580..104P }}</ref> or by diffused [[cosmic infrared background]].<ref name=":2" />
In 2002, H1426+428 exhibited variability in the 3-24 keV [[X-ray spectroscopy|X-ray spectra]].<ref>{{Cite journal |last=Falcone |first=A.D. |date=April 2004 |title=X-ray and TeV observations of the extreme BL Lac AGN H1426+428 during 2002 |url=http://dx.doi.org/10.1016/j.newar.2003.12.051 |journal=New Astronomy Reviews |volume=48 |issue=5–6 |pages=415–417 |doi=10.1016/j.newar.2003.12.051 |bibcode=2004NewAR..48..415F |issn=1387-6473|url-access=subscription }}</ref> However in 2006, it was in a period of X-ray inactivity, showing no gamma rays, when observed by [[Cherenkov Telescope Array|CELESTE Cherenkov telescope]] .<ref>{{Cite journal |last1=Smith |first1=D. A. |last2=Brion |first2=E. |last3=Britto |first3=R. |last4=Bruel |first4=P. |last5=Bussons Gordo |first5=J. |last6=Dumora |first6=D. |last7=Durand |first7=E. |last8=Eschstruth |first8=P. |last9=Espigat |first9=P. |last10=Holder |first10=J. |last11=Jacholkowska |first11=A. |last12=Lavalle |first12=J. |last13=Le Gallou |first13=R. |last14=Lott |first14=B. |last15=Manseri |first15=H. |date=2006-09-12 |title=Mrk 421, Mrk 501, and 1ES 1426+428 at 100 GeV with the CELESTE Cherenkov telescope |url=https://www.aanda.org/articles/aa/pdf/2006/44/aa5884-06.pdf |journal=Astronomy & Astrophysics |volume=459 |issue=2 |pages=453–464 |doi=10.1051/0004-6361:20065884 |arxiv=astro-ph/0608247 |bibcode=2006A&A...459..453S |issn=0004-6361}}</ref> The Tev activity in H1426+428 only increased just before 2008, with it experiencing flare activity for four days in 2009.<ref>{{Cite journal |last1=Strigunov |first1=K. S. |last2=Zhovtan |first2=A. V. |date=March 2015 |title=Long-term observations of the blazar 1ES 1426+428 with the GT-48 Cerenkov telescope |url=http://dx.doi.org/10.1134/s1063772915020079 |journal=Astronomy Reports |volume=59 |issue=3 |pages=175–182 |doi=10.1134/s1063772915020079 |bibcode=2015ARep...59..175S |issn=1063-7729|url-access=subscription }}</ref> A long-term X-ray [[flare]] was detected in H1426+428 in January 2021 by the [[X-ray telescope]] onboard [[Neil Gehrels Swift Observatory]].<ref>{{Cite journal |last=Kapanadze |first=Bidzina |date=2021-04-01 |title=Long-Term X-ray Flaring Activity of the TeV-Detected Blazar H1426+428 |url=https://ui.adsabs.harvard.edu/abs/2021ATel14560....1K/abstract |journal=The Astronomer's Telegram |volume=14560 |pages=1|bibcode=2021ATel14560....1K }}</ref> This was followed by a very high energy gamma ray flux in March 2021.<ref>{{Cite journal |last=Quinn |first=John |date=March 2021 |title=VERITAS detection of an elevated VHE flux from the blazar H 1426+428 |url=https://ui.adsabs.harvard.edu/abs/2021ATel14501....1Q/abstract |journal=The Astronomer's Telegram|volume=14501 |page=1 |bibcode=2021ATel14501....1Q }}</ref>
H1426+428 has a compact radio core with a ~ 17 [[Jansky|mJy]] flux density. In additional, it has a faint [[Astrophysical jet|radio jet]] extending towards northwest with a project [[position angle]] of -25°.<ref>{{Cite journal |last1=Piner |first1=B. Glenn |last2=Pant |first2=Niraj |last3=Edwards |first3=Philip G. |date=May 2008 |title=The Parsec-Scale Jets of the TeV Blazars H1426+428, 1ES 1959+650, and PKS 2155−304: 2001–2004 |url=https://iopscience.iop.org/article/10.1086/533521/pdf |journal=The Astrophysical Journal |volume=678 |issue=1 |pages=64–77 |doi=10.1086/533521 |arxiv=0801.2749 |bibcode=2008ApJ...678...64P |issn=0004-637X}}</ref> There is also a faint [[radio halo]] that is surrounding the radio core as well<ref>{{Cite journal |last1=Giroletti |first1=M. |last2=Giovannini |first2=G. |last3=Taylor |first3=G. B. |last4=Falomo |first4=R. |date=October 2004 |title=A Sample of Low-Redshift BL Lacertae Objects. I. The Radio Data |url=https://iopscience.iop.org/article/10.1086/423231/fulltext/ |journal=The Astrophysical Journal |volume=613 |issue=2 |pages=752–769 |doi=10.1086/423231 |arxiv=astro-ph/0406255 |bibcode=2004ApJ...613..752G |issn=0004-637X}}</ref> but it has weak radio and optical [[Polarization (waves)|polarization]].<ref>{{Cite journal |last1=Kollgaard |first1=R. I. |last2=Gabuzda |first2=D. C. |last3=Feigelson |first3=E. D. |date=March 1996 |title=Parsec-Scale Radio Structure of Four X-Ray--selected BL Lacertae Objects |url=https://articles.adsabs.harvard.edu//full/1996ApJ...460..174K/0000175.000.html |journal=The Astrophysical Journal |volume=460 |pages=174 |doi=10.1086/176959 |bibcode=1996ApJ...460..174K |issn=0004-637X}}</ref>
== References == <references />
== External links == *[http://simbad.u-strasbg.fr/simbad/sim-id?Ident=QSO%20B1426%2B428 H1423+428 on SIMBAD] *[http://ned.ipac.caltech.edu/cgi-bin/objsearch?search_type=Obj_id&objid=150299&objname=1&img_stamp=YES&hconst=73.0&omegam=0.27&omegav=0.73&corr_z=1 H1423+428 on NASA/IPAC Extragalactic Database]
{{Boötes}}
[[Category:BL Lacertae objects]] [[Category:Boötes]] [[Category:Blazars]] [[Category:Active galaxies]] [[Category:LEDA objects|2203750]] [[Category:Astronomical objects discovered in 1984]]