Tracing Sagittarius Structure with SDSS and SEGUE Imaging and Spectroscopy

Journal Article · Fri May 01 00:00:00 EDT 2009 · Astrophys.J.

DOI:https://doi.org/10.1088/0004-637X/700/2/1282· OSTI ID:3019876

Yanny, Brian ^[1]; Newberg, Heidi Jo ^[2]; Johnson, Jennifer A. ^[3]; Lee, Young Sun ^[4]; Beers, Timothy C. ^[4]; Bizyaev, Dmitry ^[5]; Brewington, Howard ^[5]; Re Fiorentin, Paola ^[6]; Harding, Paul ^[7]; Malanushenko, Elena ^[5]; Malanushenko, Viktor ^[5]; Oravetz, Dan ^[5]; Pan, Kaike ^[5]; Simmons, Audrey ^[5]; Snedden, Stephanie ^[5]

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1. Fermilab
2. Rensselaer Poly.
3. Ohio State U.
4. Michigan State U.
5. Apache Point Observ.
6. Ljubljana U.; Heidelberg, Max Planck Inst. Astron.
7. Case Western Reserve U.

We show that the Sagittarius dwarf tidal stream can be traced with very red K/M-giant stars selected from SDSS photometry. A subset of these stars are spectroscopically confirmed with SEGUE and SDSS spectra, and the distance scale of 2MASS and SDSS M giants is calibrated to the RR Lyrae distance scale. The absolute g band magnitude of the K/M-giant stars at the tip of the giant branch is M_g=-1.0. The line-of-sight velocities of the M giant and BHB stars that are spatially coincident with the Sgr dwarf tidal stream are consistent with those of previous authors, reinforcing the need for new models that can explain all of the Sgr tidal debris stream observations. We estimate stellar densities along the tidal tails that can be used to help constrain future models. The K/M-giant, BHB, and F-turnoff stars in the lower surface brightness tidal stream that is adjacent to the main leading Sgr dwarf tidal tail have velocities and metallicities that are similar to those of the stars in the leading tidal tail. The ratio of K/M giants to BHBs and BHBs to F-turnoff stars are also similar for both branches of the leading tidal tail. We show that there is an additional low-metallicity tidal stream near the Sgr trailing tidal tail.

• Research Organization: Ohio State U.; Michigan State U.; Rensselaer Poly.; Case Western Reserve U.; Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Ljubljana U.; Heidelberg, Max Planck Inst. Astron.; Apache Point Observ.
• Sponsoring Organization: US Department of Energy
• DOE Contract Number: AC02-07CH11359
• OSTI ID: 3019876
• Report Number(s): FERMILAB-PUB-09-356-A-CD; oai:inspirehep.net:821494; arXiv:0905.4502
• Journal Information: Astrophys.J., Journal Name: Astrophys.J. Vol. 700
• Country of Publication: United States
• Language: English