Two new quasars have recently been found through X-ray observations (the only other one being 3C273, see refs 1, 2). Ricker et al.3 have reported observations confirming the identification of the X-ray source 2251–178 with a quasar of visual magnitude 14.1. Canizares, McClintock, and Ricker4 have reported visual spectrophotometric observations of this quasar, and find its visual spectrum is much like other low redshift quasars. Apparao et al.5 have reported the discovery of a low redshift quasar identified with the X-ray source 4U0241 + 61. Margon and Kwitter6 have reported detailed visual spectrophotometry of this quasar, 0241 + 622, and likewise find that its spectrum is typical of low redshift quasars. Because of the importance of establishing any morphologically unique characteristics of X-ray quasars, these quasars should be observed at all possible wavelengths. We report here IR observations of the two newly discovered X-ray quasars. These observations indicate that the X-ray quasars have IR properties typical of low redshift quasars, and, along with 3C273, are among the brightest known quasars at IR wavelengths.
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SOIFER, B., NEUGEBAUER, G. & MATTHEWS, K. Infrared observations of the X-ray quasars 0241 + 622 and MR2251–178. Nature 278, 231–232 (1979). https://doi.org/10.1038/278231a0
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