Abstract
UNIDENTIFIED X-ray sources at high galactic latitudes have been the subject of much discussion (see ref. 1 and refs therein). We call attention here to the existence of a rich Abell cluster of galaxies in the error box of the Uhuru high galactic latitude source 3U1706+32. The X-ray error box is rather large (9.8 square degrees), and the apparent intensity of the source is Rx=4.1+0.6 counts s−1 in Uhuru counts2. The cluster, Abell 2241, is located at 16 h 57.8 min+32°37′ (1950)3; it belongs to distance group 3 and has an estimated redshift, z ≈ 0.07 (ref. 3). The cluster is of richness group 0 (ref. 3) and has been classified4 as an irregular (I) cluster. The positional agreement between this cluster and 3U1706+32 was not reported in the survey of positional correlations between 3U X-ray sources and Abell clusters of galaxies of distance groups, D≤3, (ref. 5). The cluster A2241 should, therefore, be added as a possible identification to the list5 of 21 clusters which have been tentatively identified with X-ray sources; no additional Abell cluster of distance group 3 or nearer lies within Uhuru2 high galactic latitude error boxes.
Similar content being viewed by others
Article PDF
References
Holt, S. S., et al., Astrophys. J. Lett., 188, L97 (1974).
Giacconi, R., et al., Astrophys. J. Suppl. Ser., 27, 37 (1974).
Abell, G. O., ibid., 3, 211 (1958).
Rood, H. J., and Sastry, G. N., Pubs. astr. Soc. Pacif., 83, 313 (1971).
Kellogg, E., Murray, S., Giacconi, R., Tananbaum, H., and Gursky, H., Astrophys. J. Lett., 185, L13 (1973).
Bahcall, N. A., Astrophys. J., 193, 529 (1974).
Fomalont, E. B., and Rogstad, D. H., ibid., 146, 528 (1966).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
BAHCALL, N. Positional agreement between 3U1706+32 and the cluster of galaxies A2241. Nature 252, 661 (1974). https://doi.org/10.1038/252661a0
Received:
Issue Date:
DOI: https://doi.org/10.1038/252661a0
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.