Abstract
Two new BL Lacertae objects, located within the error boxes of hard X-ray sources, have been discovered during a systematic program to identify a large sample of EXOSAT serendipitous sources. Both hard X-ray sources were detected during the HEAD 1 whole sky survey and have been associated to a Seyfert galaxy and to a Be star. The EXOSAT data are consistent with the two BL Lacs being the only counterparts of the hard X-ray sources. If this is the case the space density of BL Lacs, at fluxes ≥ 3 x 10−11 erg cm −2 s −1 (2–10 keV), might be higher than previously thought. The implications for the shape on the X-ray LogN-LogS of BL Lac objects are briefly discussed.
This is a preview of subscription content, log in via an institution to check access.
Preview
Unable to display preview. Download preview PDF.
References
Burbidge G., and Hewitt A., 1987 Astron. J. 92, 1.
DeKorte P.A.J. et al. 1981, Space Sci. Rev., 30, 495.
Fairall A.P., McHardy I.M., and Pye J.P., 1982, M.N.R.A.S., 198, 13P.
Giommi P., Barr P., Garilli B., Maccagni D., and Pollock A., 1988, Proc of the COSPAR-IAU Symp. on “The Physics of Compact Objects”, N.E. White and L.G. Filipov editors, Sofia, Bulgaria, p. 79.
Giommi P., Beuermann K., Barr. P., Schwope A. Tagliaferri G., and Thomas, H.C., 1989 M.N.R.A.S. in press.
Giommi P., Tagliaferri G., and Angelini L., 1988 in “X-Ray Astronomy with EXOSAT”, N.E. White and R. Pallavicini editors, Memorie S.A.It. 59, in press.
Giommi, P., Tagliaferri, G., Beuermann, K., Branduardi-Raymont, G., Brissenden, R., Graser, U., Mason, K.O., Murdin, P., Pooley, G., Thomas, H.-C., and Tuohy, I., this conference
Ledden J.E., and O'Dell S.L., 1985, Ap.J., 298, 630
Maccacaro T., Gioia I.M., Maccagni D., and Stocke J.T., 1984, Ap.J. (Letters), 284, L23.
Maccacaro T., Gioia, I.M., Schild R.E., Wolter A., Morris S.L., and Stocke J.T, 1988, this conference
McHardy I.M., Lawrence A., Pye J.P., and Pounds K.A., 1981, M.N.R.A.S., 197, 893.
Piccinotti G. Mushotzky R.F., Boldt E.A., Holt S.S, Marshall F.E., Serlemitsos P.J., and Shafer R.A., 1982, Ap.J., 253, 485.
Pounds K.A., and Turner T.J. 1988, in “X-Ray Astronomy with Exosat”, N.E. White and R. Pallavicini editors, Memorie S.A.It., 59, 1.
Stark A., Heiles C., Baily, and Linke K., 1988, in preparation.
Stocke J.T., Morris S.L., Gioia I.M., Maccacaro T., Schild R.E., and Wolter A., 1988 Proc. of the Workshop on “Optical Surveys for Quasars”, Tucson, in press.
Schwartz D.A., Brand, H., Buckley, D., Patterson, J., Remillard, R., Roberts, W., and tuohy, I. 1984. In X-Ray Astronomy '84, M. Oda and R. Giacconi editors (ISAS, Tokyo), p. 455.
Taylor B.G., Andresen R.D., Peacock A., and Zobl R., 1981, Space Sci. Rev., 30, 479.
Turner M.J.L., Smith A., and Zimmermann H.U. 1981, Space Sci. Rev., 30, 513.
White N.E. and Peacock A., 1988, in “X-ray Astronomy with EXOSAT”, N.E. White and R. Pallvicini ed., Memorie S.A.It, 59, in press
Wood K. et al., 1984, Ap.J. Suppl. 56, 507
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 1989 Springer-Verlag
About this paper
Cite this paper
Tagliaferri, G. et al. (1989). Two new BL Lacertae objects discovered in the error boxes of hard X-ray sources. In: Maraschi, L., Maccacaro, T., Ulrich, M.H. (eds) BL Lac Objects. Lecture Notes in Physics, vol 334. Springer, Berlin, Heidelberg. https://doi.org/10.1007/BFb0031170
Download citation
DOI: https://doi.org/10.1007/BFb0031170
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-51389-6
Online ISBN: 978-3-540-46203-3
eBook Packages: Springer Book Archive