منابع مشابه
Luminous Red Variable Star
We report photometry and spectroscopy of the evolution of Nova Sagittarii 1994 #1 (V4332 Sagittarii) during outburst. We compare the photometric and spectral evolution of this outburst to known classes of outbursts – including classical novae and outbursts occurring on symbiotic stars – and find this object does not conform to any known class of outburst. The closest match to the behavior of th...
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We have applied the image subtraction method to images of the peculiar, bimodal-horizontal branch globular cluster NGC 2808, taken over a total of six nights over a range of five months. As a result, we have found, for the first time, a sizeable population of variable stars in the crowded inner regions of the cluster, thus raising the known RR Lyrae population in the cluster to a total of 18 st...
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The radio source Hercules A resides at the center of a cooling flow cluster of galaxies at redshift z = 0.154. A Chandra X-ray image reveals a shock front in the intracluster medium (ICM) surrounding the radio source, about 160 kpc from the active galactic nucleus (AGN) that hosts it. The shock has a Mach number of 1.65, making it the strongest of the cluster-scale shocks driven by an AGN outbu...
متن کاملThe Hercules-aquila Cloud
We present evidence for a substantial overdensity of stars in the direction of the constellations of Hercules and Aquila. The Cloud is centered at a Galactic longitude of l ≈ 40◦ and extends above and below the Galactic plane by at least 50◦. Given its off-centeredness and height, it is unlikely that the Hercules-Aquila Cloud is related to the bulge or thick disk. More likely, this is a new str...
متن کاملA Comparison between New Estimation and variable Selectiion method in Regression models by Using Simulation
In this paper some new methods whitch very recently have been introduced for parameter estimation and variable selection in regression models are reviewd. Furthermore , we simulate several models in order to evaluate the performance of these methods under diffrent situation. At last we compare the performance of these methods with that of the regular traditional variable selection methods such ...
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ژورنال
عنوان ژورنال: Astronomische Nachrichten
سال: 1890
ISSN: 0004-6337,1521-3994
DOI: 10.1002/asna.18901250511