In Casares et al. we presented the first radial velocity curve of the companion star to BW Cir which demonstrates the presence of a black hole in this historical X-ray transient. But these data were affected by aliasing and two possible periods at 2.5445 days and 2.5635 days were equally possible. Here we present new spectroscopic data that enable us to break the 1-year aliasing and confirm 2.5445 days as the correct orbital period. We also present R-band photometry over 14 years, which reveals the presence of important flaring activity dominating the light curves.
Eight active galactic nuclei (AGNs; seven type 1 seyferts and one QSO) are reported. They are 14th and 15th mag objects with broad hydrogen lines and redshifts in the range 0.026 < z < 0.138. The AGNs were discovered in a systematic program to identify the fainter X-ray sources of the HEAO 1 survey. All are located in or near the X-ray positions of the HEAO 1 scanning modulation collimator, the HEAO 1 Large Area Sky Survey, and other X-ray experiments. The AGNs are H0307-730, PKS 0558-504, H0707-495, HI 143-182, HI839-786, HI934-513, H2106-099, and H2132-626. The X-ray and optical luminosities and many of the optical emission features of these AGNs resemble other bright and nearby Seyfert 1 galaxies. However, three of the galaxies exhibit very strong Fe n emission, and two additionally show very weak forbidden line spectra similar to I Zw 1. One of the I Zw 1 types, the previously unidentified radio source PKS 0558-504, is a QSO with unusually narrow hydrogen lines for a highluminosity object (M v =-25.1). The other, H0707-495, has an Fe n/H/? emission ratio that is similar to the largest known values. Another galaxy, H2106-099, has relatively strong emission lines of Fe x and Fe vu, and it is a variable X-ray source. Finally, the one for which we have X-ray spectral measurements, H1839-786, exhibits an unusually hard power-law spectrum with an X-ray energy index of 0.1. We have detected weak radio emission from the two Seyfert galaxies accessible from the VLA (H2106-099 and HI 143-182). Photometric magnitudes and the intensities of selected emission lines are given for each of the AGNs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.