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A pole-count analysis of the infrared 2MASS survey is presented, in order to identify faint stream-like structures within the halo of the Milky Way. Selecting stars with colours consistent with M-giant stars, we find a strong over-density of sources on a stream with pole (l=95,b=13), which corresponds to the pole of the orbit of the Sagittarius dwarf galaxy. This great-circle feature of width ~12 degrees, contains 5% of the late M-giants in the Halo. No other stream-like structures are detected in M-giants in the 2MASS Second Incremental Data Release (2IDR), and in particular, we find no evidence for a stellar component to the Magellanic Stream. This suggests that the present accretion rate of low-mass satellites with a luminous component is very low, and the formation of the luminous component of the Halo must have been essentially complete before the accretion of the Sagittarius dwarf galaxy, more than 3Gyr ago. We also search for great-circle streams using almost all high-latitude (|b|>30) sources in the 2IDR dataset. No narrow great-circle streams of width 0.5-2 degrees were found, though we were only sensitive to relatively nearby (<17kpc) remnants of massive (10^6 Msun) globular clusters. If the Galactic potential is close to being spherical, as some recent observations suggest, the lack of observed great-circle streams is consistent with the presence of dark matter substructures in the Halo. Although alternative explanations cannot be ruled out from our analysis of the 2IDR dataset, future experiments with better statistics have the potential to reveal the heating effect of dark matter substructure on stellar streams.
We estimate the acceleration on the Local Group (LG) from the Two Micron All Sky Redshift Survey (2MRS). The sample used includes about 23,200 galaxies with extinction corrected magnitudes brighter than K_s=11.25 and it allows us to calculate the flu
We present the culmination of our near-infrared survey of the optically spectroscopically identified white dwarf stars from the McCook & Sion catalog, conducted using photometric data from the Two Micron All Sky Survey final All Sky Data Release. The
We introduce the properties of the Two Micron All-Sky Survey (2MASS) survey for IAU Symposium 204. 2MASS is a near-infrared survey of the entire sky characterized by high reliability and completeness. Catalogs and images for 47% of the sky are now av
The sub-millimetre wavelength regime is perhaps the most poorly explored over large areas of the sky, despite the considerable effort that has been expended in making deep maps over small regions. As a consequence the properties of the sub-millimetre
We have detected over 400 HI clouds in the lower halo of the Galaxy within the pilot region of the Galactic All-Sky Survey (GASS), a region of the fourth quadrant that spans 18 degrees in longitude, 40 degrees in latitude and is centered on the Galac