ar X iv : a st ro - p h / 97 07 04 3 v 1 3 J ul 1 99 7 OSSERVATORIO
نویسنده
چکیده
New ages are computed for the stars from the Edvardsson et al. (1993) data set. The revised values are systematically larger toward older ages (t>4 Gyr), while they are slightly lower for t<4 Gyr. The systematic difference to older age becomes ∼2 Gyr smaller, when the LutzKelker correction is applied. The Lutz-Kelker corrected values are slightly older than the ages computed from the Hipparcos parallaxes. The resulting age-metallicity relation has a small, but distinct slope of ∼0.07 dex/Gyr.
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ar X iv : a st ro - p h / 97 07 04 5 v 1 3 J ul 1 99 7 New radio observations of Circinus X - 1
New radio observations of the radio-jet X-ray binary Circinus X-1 over nearly an entire 16.6-day orbit are presented. The source continues to undergo radio flaring in the phase interval 0.0 – 0.2 and appears to be brightening since observations in the early 1990s. The radio flux density is well correlated with simultaneous soft Xray monitoring from the XTE ASM, including a secondary flare event...
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ar X iv : a st ro - p h / 99 04 24 4 v 2 3 J un 1 99 9 Is SGR 1900 + 14 a Magnetar ?
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