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تسجيل مستخدم جديدThe Relationship Between X-ray Luminosity and Duty Cycle for Dwarf Novae and their Specific Frequency in the Inner Galaxy
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We measure the duty cycles for an existing sample of well observed, nearby dwarf novae using data from AAVSO, and present a quantitative empirical relation between the duty cycle of dwarf novae outbursts and the X-ray luminosity of the system in quiescence. We have found that $log DC=0.63(pm0.21)times(log L_{X}({rm erg,s^{-1}})-31.3)-0.95(pm0.1)$, where DC stands for duty cycle. We note that there is intrinsic scatter in this relation greater than what is expected from purely statistical errors. Using the dwarf nova X-ray luminosity functions from citet{Pretorius12} and citet{Byckling10}, we compare this relation to the number of dwarf novae in the Galactic Bulge Survey which were identified through optical outbursts during an 8-day long monitoring campaign. We find a specific frequency of X-ray bright ($L_{X}>10^{31},{rm erg,s^{-1}}$) Cataclysmic Variables undergoing Dwarf Novae outbursts in the direction of the Galactic Bulge of $6.6pm4.7times10^{-5},M_{odot}^{-1}$. Such a specific frequency would give a Solar neighborhood space density of long period CVs of $rho=5.6pm3.9times10^{-6},$pc$^{-3}$. We advocate the use of specific frequency in future work, given that projects like LSST will detect DNe well outside the distance range over which $rhoapprox{textrm const}$.
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