The QUEST RR Lyrae Survey: Confirmation of the Clump at 50 Kiloparsecs and Other Overdensities in the Outer Halo

Vivas, A. K.; Zinn, R.; Andrews, P.; Bailyn, C.; Baltay, C.; Coppi, P.; Ellman, N.; Girard, T.; Rabinowitz, D.; Schaefer, B.; Shin, J.; Snyder, J.; Sofia, S.; van Altena, W.; Abad, C.; Bongiovanni, A.; Briceño, C.; Bruzual, G.; Della Prugna, F.; Herrera, D.; Magris, G.; Mateu, J.; Pacheco, R.; Sánchez, Ge.; Sánchez, Gu.; Schenner, H.; Stock, J.; Vicente, B.; Vieira, K.; Ferrín, I.; Hernandez, J.; Gebhard, M.; Honeycutt, R.; Mufson, S.; Musser, J.; Rengstorf, A.
Bibliographical reference

The Astrophysical Journal, Volume 554, Issue 1, pp. L33-L36.

Advertised on:
6
2001
Number of authors
36
IAC number of authors
0
Citations
213
Refereed citations
178
Description
We have measured the periods and light curves of 148 RR Lyrae variables from V=13.5 to 19.7 from the first 100 deg2 of the Quasar Equatorial Survey Team RR Lyrae survey. Approximately 55% of these stars belong to the clump of stars detected earlier by the Sloan Digital Sky Survey. According to our measurements, this feature has ~10 times the background density of halo stars, spans at least 37.5d by 3.5d in α and δ (>=30 by >=3 kpc), lies ~50 kpc from the Sun, and has a depth along the line of sight of ~5 kpc (1 σ). These properties are consistent with the recent models that suggest that it is a tidal stream from the Sagittarius dwarf spheroidal galaxy. The mean period of the type ab variables, 0.58 days, is also consistent. In addition, we have found two smaller overdensities in the halo, one of which may be related to the globular cluster Pal 5.