Candidate RR Lyrae Stars Found in Sloan Digital Sky Survey Commissioning Data

By Željko Ivezic´, J. Goldston, K. Finlator, G. Knapp, Brian Yanny, T. McKay, S. Amrose, K. Krisciunas, B. Willman, S. Anderson and 32 more. 2000

208 citations recorded by the source corpus.

We present a sample of 148 candidate RR Lyrae stars selected from Sloan Digital Sky Survey (SDSS) commissioning data for about 100 deg2 of sky surveyed twice with Δt = 1.9946 days. Although the faint-magnitude limit of the SDSS allows us to detect RR Lyrae stars to large Galactocentric distances (∼100 kpc, or r* ∼ 21), we find no candidates fainter than r* ∼ 20, i.e., farther than ∼65 kpc from the Galactic center. On the assumption that all 148 candidates are indeed RR Lyrae stars (contamination by other species of variable star is probably less than 10%), we find that their volume density has roughly a power-law dependence on Galactocentric radius, R-2.7±0.2, between 10 and 50 kpc and drops abruptly at R ∼ 50–60 kpc, possibly indicating a sharp edge to the stellar halo as traced by RR Lyrae stars. The Galactic distribution of stars in this sample is very inhomogeneous and shows a clump of over 70 stars at about 45 kpc from the Galactic center. This clump is also detected in the distribution of nonvariable objects with RR Lyrae star colors. When sources in the clump are excluded, the best power-law fit becomes consistent with the R-3 distribution found from surveys of bright RR Lyrae stars. These results imply that the halo contains clumpy overdensities inhomogeneously distributed within a smooth R-3 background, with a possible cutoff at ∼50 kpc.

Subfields: Astronomy and Astrophysics

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Citations in the corpus

Detection of Massive Tidal Tails around the Globular Cluster Palomar 5 with Sloan Digital Sky Survey Commissioning Data (2000, background): “Such a high-quality database is ideally suited for studies of Galactic structure (e.g., Yanny et al. 2000; Ivezic et al. 2000) and lends itself in particular to searches for tidal debris with unprecedented depth and spatial coverage.”
Solar System Objects Observed in the Sloan Digital Sky Survey Commissioning Data (2001, methodology): “The photometric errors determined by comparing measurements for stars observed in two epochs are about 2-3% for objects at the bright end, and then start increasing due to photon counting noise (for more details see Ivezić et al. 2000).”
The QUEST RR Lyrae Survey: Confirmation of the Clump at 50 Kiloparsecs and Other Overdensities in the Outer Halo (2001, background): “The slope of this line (-3.0±0.2) is consistent with previous determinations (Wetterer & McGraw 1996, Ivezic et al. 2000) of the density fall-off in the halo7.”
A Two Micron All Sky Survey View of the Sagittarius Dwarf Galaxy. I. Morphology of the Sagittarius Core and Tidal Arms (2003, background): “The distances of these more distant RR Lyraes are also in reasonably good agreement with the M-giant distribution presented here ( 270 310 , Fig.”
The Ghost of Sagittarius and Lumps in the Halo of the Milky Way (2001, background): “…dwarf and our 110 deg2 patch of sky on the equator is striking and leaves little doubt that the tidally disrupted clumps of stars discovered in Ivezić et al. (2000) and Paper I are in fact pieces of the Sagittarius dwarf stream, in exactly the positions predicted by Ibata et al. (2001b).”
The QUEST RR Lyrae Survey. II. The Halo Overdensities in the First Catalog (2006, methodology): “This striking overdensity was discovered in the spatial distribution of A stars (Yanny et al. 2000) and RRLS candidates (Ivezić et al. 2000).”
Tracing Galaxy Formation with Stellar Halos. II. Relating Substructure in Phase and Abundance Space to Accretion Histories (2008, background): “…distribution around both the Milky Way and Andromeda galaxies, already seen at a few tens of kpc from their centers, and dominant at 100kpc (e.g. Ivezić et al. 2000; Newberg et al. 2002, 2003; Ferguson et al. 2002; Majewski et al. 2003; Belokurov et al. 2006; Ibata et al. 2007, and see §6.1…”
The Haunted Halos of Andromeda and Triangulum: A Panorama of Galaxy Formation in Action (2007, unknown): “The stellar volume density is generally modeled as ρ(r) ∝ r−α, and recent studies (Wetterer & McGraw 1996; Morrison et al. 2000; Yanny et al. 2000; Ivezic et al. 2000; Siegel et al. 2002; Vivas & Zinn 2006) have found values of the exponent ranging from α = 3.55 ± 0.13 (Chiba & Beers 2000) to α =…”
Mapping the substructure in the Galactic halo with the next generation of astrometric satellites (2000, background): “Moreover, recent observations have shown that indeed considerable structure is still present in Milky Way’s halo, indicating that accretion events have had some role in its formation history (e.g. Ibata, Gilmore & Irwin 1994; Majewski, Munn & Hawley 1996; Helmi et al. 1999; Ivezic et al. 2000).”
Tracing Galaxy Formation with Stellar Halos. I. Methods (2005, background): “…shape and extent of the Milky Way’s stellar halo come either from star count surveys (Morrison et al. 2000; Chiba & Beers 2000; Yanny et al. 2000; Siegel, Majewski, Reid, & Thompson 2002) or studies where distances could be estimated using RR Lyraes (Wetterer & McGraw 1996; Ivezić et al. 2000) .”
LIGHT CURVE TEMPLATES AND GALACTIC DISTRIBUTION OF RR LYRAE STARS FROM SLOAN DIGITAL SKY SURVEY STRIPE 82 (2009, methodology): “The g-band magnitudes are used instead of u- or r-band magnitudes because they have higher signal-to-noise ratios than the u-band magnitudes, and because RR Lyrae stars have a larger amplitude of variability in the g band than in the r band (Ivezić et al. 2000, S07).”
The stellar halo of the Galaxy (2008, methodology): “However, Yanny et al. (2000) estimated n = −3.2 ± 0.3 and q = 0.65 2 http://www.sdss.org (after masking out the overdensities due to the Sagittarius streams), in accordance with Ivezić et al. (2000) who found n ∼ −3.”
STRUCTURE AND KINEMATICS OF THE STELLAR HALOS AND THICK DISKS OF THE MILKY WAY BASED ON CALIBRATION STARS FROM SLOAN DIGITAL SKY SURVEY DR7 (2009, methodology): “It is thus of interest to note that Ivezić et al. (2000), based on a sample of RR Lyraes located between 10 and 50 kpc from the Galactic center selected from SDSS commisioning data, obtained a slope of −2.7± 0.2.”
The Milky Way Tomography with SDSS. II. Stellar Metallicity (2008, background): “However, recent discoveries of complex substructure in the distribution and kinematics of the Milky Way’s stars (e.g. Ivezić et al. 2000; Yanny et al. 2000; Vivas et al. 2001; Newberg et al. 2002; Gilmore, Wyse & Norris 2002; Majewski et al. 2003; Duffau, Zinn & Vivas 2006; Vivas & Zinn 2006;…”
Sloan Digital Sky Survey: Early Data Release (2002, background): “…2001); the luminosities and colors of galaxies (Blanton et al. 2001; Shimasaku et al. 2001; Strateva et al. 2001); the structure of the Milky Way (Ivezić et al. 2000; Yanny et al. 2000; Chen et al. 2001); the discovery of brown dwarfs (Leggett et al. 2000 and references therein); the structure…”
Shredded Galaxies as the Source of Diffuse Intrahalo Light on Varying Scales (2007, background): “The stellar halo of the Milky Way contains fIHL 1% of the Galaxy’s total luminosity (Morrison 1993; Wetterer & McGraw 1996; Morrison et al. 2000; Chiba & Beers 2000; Yanny et al. 2000; Ivezić et al. 2000; Siegel et al. 2002).”
The Cosmic Energy Inventory (2004, background): “For the Milky Way the distribution of RR Lyr stars cuts off sharply at 50 kpc (Ivezić et al. 2000).”