Early-type stars in orthogonal halo fields. I - an objective-prism survey

Rodgers, A. W.; Roberts, W. H.; Walker, Ian R.

doi:10.1086/116663

Cited by 7 publications

(23 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The spectroscopic data for these stars are summarized in Table 3. Kinemuchi et al (2006) found a fourth and fainter type ab RR Lyrae star (N SV S 14602495; R.A. 23:15:56.66, DEC. +03:02:58 (2000)) within the N R field but not identified by Rodgers et al (1993a). It has a period of 0.59355 days and a V amplitude of 1.56 mag, from which they derived an [Fe/H] of -2.60.…”

Section: Rr Lyrae Stars In N Rmentioning

confidence: 99%

“…• 0. Rodgers et al (1993a) list 259 early-type stars in this field and give radial velocities for 191 of them. This field has the same galactic coordinates as the (l,b) = (270 • ,-45 • ) field observed by Gilmore et al (2002) although the SR field covers a much larger area to a brighter limiting magnitude.…”

Section: Fieldmentioning

confidence: 99%

“…The B2M survey overlaps ∼50% of the area of the N R survey. In this overlap region they list 45 stars; 28 of these were given by Rodgers et al (1993a) and which we include in our list of BHB candidates ( Table 5). The 17 stars not listed by Rodgers et al are given separately in Table 10 in Appendix B; these are mostly stars that are either too red or too faint to have been included in the N R survey.…”

Section: Introductionmentioning

confidence: 99%

“…BHB stars can be identified with considerable certainty, for example, by using a (B − V ) vs (u − B) K plot (Kinman et al 1994).GALEX ultraviolet magnitudes can also be used to identify BHB stars (Kinman et al 2007b). Rodgers et al (1993a) give no colors for their stars, only V magnitudes calculated from the Hubble Space Telescope (HST ) Guide Star Catalog (Lasker et al 1990). We therefore obtain V , (B −V ) and (u−B) K photometry for most of the stars of spectral type A8 and earlier in the N R field.…”

mentioning

confidence: 99%

See 3 more Smart Citations

The BHB Stars in the Survey Fields of Rodgers Et Al. (1993): New Observations and Comparisons With Other Recent Surveys

Kinman¹,

Brown

2011

The Astronomical Journal

View full text Add to dashboard Cite

We study blue horizontal branch (BHB) and RR Lyrae stars in the Rogers et al. (1993a) fields and compare their velocity and density distributions with other surveys in the same part of the sky. Photometric data are given for 176 early-type stars in the northern field. We identify fourteen BHB stars and four possible BHB stars, and determine the selection efficiency of the Century Survey, the HK Survey, and the SDSS survey for BHB stars. We give light curves and γ radial velocities for three type ab RR Lyrae stars in the northern field; comparison with the nearby LON EOS Survey shows that there is likely to be an equal number of lower-amplitude type ab RR Lyrae stars that we do not find. There are therefore at least twice as many BHB stars as type ab RR Lyrae stars in the northern field -similar to the ratio in the solar neighborhood. The velocity distribution of the southern field shows no evidence for an anomalous thick disk that was found by Gilmore et al. (2002); the halo velocity peaks at a slightly prograde rotational velocity but there is also a significant retrograde halo component in this field. The velocity distribution in the northern field shows no evidence of Galactic rotation for |Z|≥ 4 kpc and a slight prograde motion for |Z|< 4 kpc. The space densities of BHB stars in the northern field agree with an extrapolation of the power-law distribution recently derived by de Propris et al. (2010). For |Z| < 4 kpc, however, we observe an excess of BHB stars compared with this power-law. We conclude that these BHB stars mostly belong to a spatially flattened, nonrotating inner halo component of the Milky Way in confirmation of the Kinman et al. (2009) analysis of Century Survey BHB stars. Subject headings: stars: horizontal branch, Galaxy: structure, Galaxy: halo by Rodgers et al. (1993c). BHB stars can be identified with considerable certainty, for example, by using a (B − V ) vs (u − B) K plot (Kinman et al. 1994).GALEX ultraviolet magnitudes can also be used to identify BHB stars (Kinman et al. 2007b). Rodgers et al. (1993a) give no colors for their stars, only V magnitudes calculated from the Hubble Space Telescope (HST ) Guide Star Catalog (Lasker et al. 1990). We therefore obtain V , (B −V ) and (u−B) K photometry for most of the stars of spectral type A8 and earlier in the N R field. Photometry is also taken from the 2MASS and GALEX catalogs. In addition, the N R field is covered by the Northern Sky Variability Survey (hereafter N SV S; Wózniak et al. 2004) and the ASAS-3 variability survey (Pojmański, 2002). We use these two surveys to study variability among the early-type stars and identify possible new RR Lyrae stars. We obtain V light-curves and phase-corrected radial velocities for the three brightest RR Lyrae stars in the N R field.The radial velocity distribution of the stars is important because the N R and SR fields have Galactic longitudes for which the sight-line component of Galactic rotation is the greatest and thus for which radial velocity can distinguish between disk and halo populati...

show abstract

Section: Rr Lyrae Stars In N Rmentioning

confidence: 99%

Section: Fieldmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

The BHB Stars in the Survey Fields of Rodgers Et Al. (1993): New Observations and Comparisons With Other Recent Surveys

Kinman¹,

Brown

2011

The Astronomical Journal

View full text Add to dashboard Cite

show abstract

“…Rodgers et al 1993). We will also find distant, high-latitude OB main-sequence stars (Brown et al 1989;Conlon et al 1990).…”

Section: Galactic Longitudementioning

confidence: 99%

The Century Survey Galactic Halo Project. I. Stellar Spectral Analysis

Brown

Prieto

Wilhelm

et al. 2003

View full text Add to dashboard Cite

The Century Survey Galactic Halo Project is a photometric and spectroscopic survey from which we select relatively blue stars (VÀR < 0.30 mag) as probes of the Milky Way halo. The survey strip spans the range of Galactic latitude 35 < b < 88 , allowing us to study the nature of populations of stars and their systematic motions as a function of Galactic latitude. One of our primary goals is to use blue horizontal-branch stars to trace potential star streams in the halo, and to test the hierarchical model for the formation of the Galaxy. In this paper we discuss spectroscopy and multipassband photometry for a sample of 764 blue stars in the Century Survey region. Our sample consists predominantly of A-and F-type stars. We describe our techniques for determination of radial velocities, effective temperatures, metallicities, and surface gravities. Based on these measurements, we derive distance estimates by comparison with a set of calibrated isochrones. We devote special attention to the classification of blue horizontal-branch stars, and compare the results obtained from the application of the techniques of Kinman et al., Wilhelm et al., and Clewley et al. We identify 55 blue horizontal-branch stars. Our large sample of stars also uncovers a number of unusual objects, including three carbon-enhanced stars, a late B-type star located 0.8 kpc above the Galactic plane, and a DZ white dwarf.

show abstract

8.3.1 Apparent distribution of galactic objects on the celestial sphere

Just¹

Interstellar Matter, Galaxy, Universe

View full text Add to dashboard Cite

Early-type stars in orthogonal halo fields. I - an objective-prism survey

Cited by 7 publications

References 1 publication

The BHB Stars in the Survey Fields of Rodgers Et Al. (1993): New Observations and Comparisons With Other Recent Surveys

The BHB Stars in the Survey Fields of Rodgers Et Al. (1993): New Observations and Comparisons With Other Recent Surveys

The Century Survey Galactic Halo Project. I. Stellar Spectral Analysis

8.3.1 Apparent distribution of galactic objects on the celestial sphere

Contact Info

Product

Resources

About