@Article{BorgesRodCoeMalCas:2020:MaWhDw,
               author = "Borges, Sarah Villanova and Rodrigues, Cl{\'a}udia Vilega and 
                         Coelho, Jaziel Goulart and Malheiro, Manuel and Castro, Manuel 
                         Antonio",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Universidade 
                         Tecnol{\'o}gica Federal do Paran{\'a} (UTFPR)} and {Instituto 
                         Tecnol{\'o}gico de Aeron{\'a}utica (ITA)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)}",
                title = "A magnetic white Dwarf accretion model for the anomalous X-ray 
                         pulsar 4U 0142+61",
              journal = "Astrophysical Journal",
                 year = "2020",
               volume = "895",
               number = "1",
                pages = "e26",
                month = "May",
             keywords = "Pulsars, Optical pulsars, White dwarf stars, Chandrasekhar limit, 
                         X-ray stars, Debris disks, Stellar accretion disks, Soft gamma-ray 
                         repeaters, Magnetars, Magnetic stars, Magnetic fields.",
             abstract = "The quiescent emission of the anomalous X-ray pulsar (AXP) 4U 
                         0142+61 extends over a broad range of energy, from radio up to 
                         hard X-rays. In particular, this object is unique among soft 
                         gamma-ray repeaters (SGRs) and AXPs in presenting simultaneously 
                         mid-infrared emission and pulsed optical emission. In spite of the 
                         many propositions to explain this wide range of emission, it still 
                         lacks one that reproduces all of the observations. Filling this 
                         gap, we present a model to reproduce the quiescent spectral energy 
                         distribution of 4U 0142+61 from mid-infrared up to hard X-rays 
                         using plausible physical components and parameters. We propose 
                         that the persistent emission comes from a magnetic accreting white 
                         dwarf (WD) surrounded by a debris disk. This model assumes that 
                         (i) the hard X-rays are due to the bremsstrahlung emission from 
                         the postshock region of the accretion column, (ii) the soft X-rays 
                         are originated by hot spots on the WD surface, and (iii) the 
                         optical and infrared emissions are caused by an optically thick 
                         dusty disk, the WD photosphere, and the tail of the postshock 
                         region emission. In this scenario, the fitted model parameters 
                         indicate that 4U 0142+61 harbors a fast-rotator magnetic 
                         near-Chandrasekhar WD, which is very hot and hence young. Such a 
                         WD can be the recent outcome of a merger of two less massive WDs. 
                         In this case, 4U 0142+61 can evolve into a supernova Ia and hence 
                         give hints of the origin of these important astrophysical events. 
                         Additionally, we also present a new estimate of 4U 0142+61's 
                         distance, 3.78(-0.18)(+0.12) kpc, based on the measured hydrogen 
                         column density and new interstellar extinction 3D maps.",
                  doi = "10.3847/1538-4357/ab8add",
                  url = "http://dx.doi.org/10.3847/1538-4357/ab8add",
                 issn = "0004-637X and 1538-4357",
             language = "en",
           targetfile = "borges_magnetic.pdf",
        urlaccessdate = "12 abr. 2021"
}