Astronomy and Astrophysics – Astrophysics
Scientific paper
2007-03-20
Mon.Not.Roy.Astron.Soc.379:1373-1389,2007
Astronomy and Astrophysics
Astrophysics
23pages,12figures,accepted by MNRAS
Scientific paper
10.1111/j.1365-2966.2007.11995.x
The halo structure at high Galactic latitudes near both the north and south poles is studied using SDSS and SuperCOSMOS data. For the south cap halo, the archive of the SuperCOSMOS photographic photometry sky survey is used. The coincident source rate between SuperCOSMOS data in $B_J$ band from $16^m.5$ to $20^m.5$ and SDSS data is about 92%, in a common sky area in the south. While that in the $R_F$ band is about 85% from $16^m.5$ to $19^m.5$. Transformed to the SuperCOSMOS system and downgraded to the limiting magnitudes of SuperCOSMOS, the star counts in the northern Galactic cap from SDSS show up to an $16.9\pm6.3%$ asymmetric ratio (defined as relative fluctuations over the rotational symmetry structure) in the $B_J$ band, and up to $13.5\pm6.7%$ asymmetric ratio in the $R_F$ band. From SuperCOSMOS $B_J$ and $R_F$ bands, the structure of the southern Galactic hemisphere does not show the same obvious asymmetric structures as the northern sky does in both the original and downgraded SDSS star counts. An axisymmetric halo model with n=2.8 and q=0.7 can fit the projected number density from SuperCOSMOS fairly well, with an average error of about 9.17%. By careful analysis of the difference of star counts between the downgraded SDSS northern halo data and SuperCOSMOS southern halo data, it is shown that no asymmetry can be detected in the south Galactic cap at the accuracy of SuperCOSMOS, and the Virgo overdensity is likely a foreign component in the Galactic halo.
Deng Li Cai
Hu Jiang-Yao
Xu Yadong
No associations
LandOfFree
The structure of the Galactic halo: SDSS versus SuperCOSMOS does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The structure of the Galactic halo: SDSS versus SuperCOSMOS, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The structure of the Galactic halo: SDSS versus SuperCOSMOS will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-122809