M. AckermannM. AjelloH. AnL. BaldiniG. BarbielliniD. BastieriR. BellazziniE. BissaldiR. D. BlandfordR. BoninoJ. BregeonR. J. BrittoP. BruelR. BuehlerG. A. CaliandroR. A. CameronM. CaragiuloP. A. CaraveoE. CavazzutiC. CecchiE. CharlesA. ChekhtmanG. ChiaroS. CipriniJ. Cohen-TanugiF. CostanzaS. CutiniF. D'AmmandoA. De AngelisF. De PalmaR. DesianteM. Di MauroL. Di VenereA. DominguezP. S. DrellC. FavuzziS. J. FeganE. C. FerraraJ. FinkeP. FuscoF. GarganoD. GasparriniN. GigliettoF. GiordanoM. GirolettiD. GreenI. A. GrenierS. GuiriecD. HoranG. JóhannessonM. KatsuragawaM. KussS. LarssonL. LatronicoJ. LiL. LiF. LongoF. LoparcoM. N. LovelletteP. LubranoJ. MagillS. MalderaA. ManfredaM. MayerM. N. MazziottaP. F. MichelsonN. MirabalW. MitthumsiriT. MizunoM. E. MonzaniA. MorselliI. V. MoskalenkoM. NegroE. NussDeutsche Elektronen-SynchrotronClemson UniversityKavli Institute for Particle Astrophysics and CosmologyUniversità di PisaIstituto Nazionale di Fisica Nucleare, RomaUniversita degli Studi di TriesteIstituto Nazionale Di Fisica Nucleare, Sezione di PadovaUniversità degli Studi di PadovaIstituto Nazionale Di Fisica Nucleare, Sezione di PisaUniversità degli Studi di TorinoLaboratoire Univers et Particules de MontpellierUniversity of JohannesburgLaboratoire Leprince-RinguetConsorzio Interuniversitario per la Fisica Spaziale (CIFS)Università degli Studi di BariINAF Istituto di Astrofisica Spaziale e Fisica Cosmica, MilanAgenzia Spaziale ItalianaUniversita degli Studi di PerugiaGeorge Mason University, Fairfax CampusOsservatorio Astronomico di RomaIstituto Di Radioastronomia, BolognaAlma Mater Studiorum Università di BolognaUniversita degli Studi di UdineUniversità degli Studi di Napoli Federico IINASA Goddard Space Flight CenterNaval Research LaboratoryUniversity of MarylandInstitut de Recherche sur les Lois Fondamentales de l'UniversUniversity Science Institute ReykjavikJAXA Institute of Space and Astronautical ScienceThe Royal Institute of Technology (KTH)Oskar Klein Centre for Cosmoparticle PhysicsUniversitat Autònoma de BarcelonaMahidol UniversityHiroshima UniversityMax Planck Institut fur Physik (Werner-Heisenberg-Institut)Medizinische Universitat InnsbruckMax Planck Institut fur extraterrestrische PhysikNYCB Realtime Computing Inc.Jet Propulsion Laboratory, California Institute of TechnologyInstitucio Catalana de Recerca I Estudis Avancats2018-12-112019-03-142018-12-112019-03-142016-03-20Astrophysical Journal. Vol.820, No.1 (2016)153843570004637X2-s2.0-84961657918https://repository.li.mahidol.ac.th/handle/20.500.14594/43583© 2016. The American Astronomical Society. All rights reserved. We have collected broadband spectral energy distributions (SEDs) of three BL Lac objects 3FGL J0022.1-1855 (z = 0.689), 3FGL J0630.9-2406 (z≳ 1.239), and 3FGL J0811.2-7529 (z = 0.774), detected by Fermi with relatively flat gigaelectronvolt spectra. By observing simultaneously in the near-infrared to hard X-ray band, we can well characterize the high end of the synchrotron component of the SED. Thus, fitting the SEDs to synchro-Compton models of the dominant emission from the relativistic jet, we can constrain the underlying particle properties and predict the shape of the gigaelectronvolt Compton component. Standard extragalactic background light (EBL) models explain the high-energy absorption well, with poorer fits for high-ultraviolet models. The fits show clear evidence for EBL absorption in the Fermi spectrum of our highest-redshift source 3FGL J0630.9-2406. While synchrotron self-Compton models adequately describe the SEDs, the situation may be complicated by possible external Compton components. For 3FGL J0811.2-7529, we also discover a nearby serendipitous source in the X-ray data, which is almost certainly another lower synchrotron peak frequency (vpksy) BL Lac, that may contribute flux in the Fermi band. Since our sources are unusual high-luminosity, moderate vpksy BL Lacs, we compare these quantities and the Compton dominance, the ratio of peak inverse Compton to peak synchrotron luminosities (LpkIC/Lpksy), with those of the full Fermi BL Lac population.Mahidol UniversityEarth and Planetary SciencesArticleSCOPUS10.3847/0004-637X/820/1/72