A Soft X-Ray Survey from the Galactic Center to VELA

A Comment on X-Ray Source Identifications

“…For example, with regard to 3U 1642-45 we are satisfied with its probable identification on positional grounds with GX 340+0 (Margon et al 1971). The coincidence with Ara-1 (Hill et al 1972) is also convincing, since the observation was made with good angular resolution, but we are dissatisfied with the momenclature used. In particular we wish to point out that the name Ara XR-1 and variations of it such as Ara-1 and Ara X-l, which are sufficiently alike to imply the same source, have in fact been used for objects other than 3U 1642-45.…”

“…The possible identifications are 3U 1624-49 with G 334.9-0.3, 3U 1642-45 with G 339.6-0.1 and 3U 1714-39 with G 348.2-1.0. In a brief discussion of the possibility of identification of optical counterparts of the first two objects, the work of rocket and balloon workers covering the energy range from 200 eV to 100 keV is cited (Margon et al 1971;Hill et aL 1972;Cooke and Pounds 1971;Davison et aL 1971) to provide evidence that distances in excess of 4 kpc are likely. We note here in passing that Uhuru's spectral measurement capability is limited from about 1.5 to 10 keV and that in order to get wideband spectral data, it is necessary to use rocket and balloon results.…”

“…The situation with 3U 1624-49 is even more confused. It is identified by Sanduleak and Dolan (1974) more or less implicitly with Nor XR-1 for which the distance in excess of 4 kpc is deduced mainly, it is presumed, from the work of Cooke and Pounds (1971) and Davison etal (1971), together with that of Hill et al (1972). There is again the problem of nomenclature, with the names Nor XR-1, Nor X-l and Nor-1 not necessarily implying the same source.…”

X-ray Variability and the Secondary Star

“…The earliest data were obtained by non-imaging detectors with fields of view defined b. [' collimators, nown on rockets or orbiting platforms [42,39,36,77,691. They established 11 Car as a source of X-rays at energies E > 5 keY, and detected iron K-line emission at 6.7 keY.…”

Absorption and Production of Soft X-Rays in the Galaxy

“…For Sco X-l, Cyg X-2 and the Cygnus Loop the experimental values are so widely scattered that the ranges of Nn x are indicated by vertical bars. References to the values of Nhx for the named sources can be found in the text, whereas the unnamed ones are based on Hill et al (1972).…”