Fast X-Ray/IR cross-correlations and relativistic jet formation in GRS 1915+105

Дата и время публикации : 2013-08-01T17:44:12Z

Авторы публикации и институты :
Nestor M. Lasso-Cabrera
Stephen S. Eikenberry

Ссылка на журнал-издание: Ссылка на журнал-издание не найдена
Коментарии к cтатье: Accepted for publication in ApJ. 34 pages, 12 figures, 4 tables
Первичная категория: astro-ph.HE

Все категории : astro-ph.HE

Краткий обзор статьи: We present cross-correlation analyses of simultaneous X-ray and near-infrared (near-IR) observations of the microquasar GRS 1915+105 during relativistic jet-producing epochs (X-ray class $alpha$ and $beta$). While previous studies have linked the large-amplitude IR flares and X-ray behaviors to jet formation in these states, our new analyses are sensitive to much lower-amplitude IR variability, providing more sensitive probes of the jet formation process. The X-ray to IR cross-correlation function (CCF) shows significant correlations which vary in form between the different X-ray states. During low/hard dips in both classes, we find no significant X-ray/IR correlation. During high-variability epochs, we find consistently significant correlations in both $alpha$ and $beta$ classes, but with strong differences in the CCF structure. The high-variability $alpha$ CCF shows strong anti-correlation between X-ray/IR, with the X-ray preceding the IR by $sim$ 13 $pm$ 2s. The high-variability $beta$ state shows time-variable CCF structure, which is statistically significant but without a clearly consistent lag. Our simulated IR light curves, designed to match the observed CCFs, show variably-flickering IR emission during the class $beta$ high-variability epoch, while the class $alpha$ can be fit by IR flickering with frequencies in the range 0.1 to 0.3 Hz, strengthening $sim$10 s after every X-ray subflare. We interpret these features in the context of the X-ray-emitting accretion disk and IR emission from relativistic jet formation in GRS 1915+105, concluding that the CCF analysis places the origin in a synchrotron-emitting relativistic compact jet at a distance from the compact object of $sim$0.02AU.

Category: Physics