Stellar Population Studies with the SDSS. I. The Vertical Distribution of Stars in the Milky Way

Chen, Bing; Stoughton, Chris; Smith, J. Allyn; Uomoto, Alan; Pier, Jeffrey R.; Yanny, B.; Ivezić, Željko; York, Donald G.; Anderson, John E.; Annis, J.; Brinkmann, J.; Csabai, István; Fukugita, M.; Hindsley, Robert B.; Lupton, Robert H.; Munn, Jeffrey A.

doi:10.1086/320647

Cited by 351 publications

(466 citation statements)

References 57 publications

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“…The halo main-sequence turnoff is the high-density ridge near (g* À r*) = 0.3, which rapidly drops off in density on the blue side, smeared vertically in magnitude below about r* = 18.5 by the spread in distance of the halo stars. The density ridgeline at about (g* À r*) = 0.4 and about 18 < r* < 16 is probably the local thick disk population (Chen et al 2001).…”

Section: No 1 2002 Tidal Tails Of Palmentioning

confidence: 95%

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A Matched-Filter Analysis of the Tidal Tails of the Globular Cluster Palomar 5

Rockosi

Odenkirchen

Grebel

et al. 2002

The Astronomical Journal

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218

217

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The tidal tails of the globular cluster Palomar 5 are analyzed over a 41 deg 2 area of the Sloan Digital Sky Survey photometric catalogs. The matched filter algorithm provides the maximum possible signal-to-noise detection of the cluster stars over the measured background, and the expected and actual effectiveness of the technique in the context of this data set is discussed. The stellar background is examined in some detail for systematic variation as a function of Galactic position in order to assess its effect on the detection efficiency. Of the total number of Pal 5 stars detected, 45% are out in the tails. The tails are found as the only additional 3 overdensity of cluster stars over the entire 41 deg 2 area studied. The annular-averaged density of stars along the tails is fitted to a power law in radius with best-fit index À1.58 AE 0.07, significantly steeper than that predicted from a constant orbit-averaged mass-loss rate.

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Section: No 1 2002 Tidal Tails Of Palmentioning

confidence: 95%

“…The distinct population on the red side of (g* À r*) = 1.0 is made up mostly of local M dwarfs in the disk (Chen et al 2001). The halo main-sequence turnoff is the high-density ridge near (g* À r*) = 0.3 with the rapid blue drop-off in density spread in magnitude below about r* = 18.5.…”

Section: No 1 2002 Tidal Tails Of Palmentioning

confidence: 99%

A Matched-Filter Analysis of the Tidal Tails of the Globular Cluster Palomar 5

Rockosi

Odenkirchen

Grebel

et al. 2002

The Astronomical Journal

Self Cite

218

217

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“…This constraint is of paramount importance to tune the vertical profiles of the disk and the vertical epicyclic oscillations of the orbits, thus several studies have investigated the vertical structure of the Milky way on the basis of different observations Chen et al 2001;Haywood, Robin & Creze 1997;Bovy et al 2012a;Levine, Heiles & Blitz 2008;Ja locha et al 2014;Soubiran, Bienaymé & Siebert 2003). We determine the vertical force at any location within the galaxy as follows.…”

Section: Vertical Forcementioning

confidence: 99%

Spiral arm kinematics for Milky Way stellar populations

Pasetto

Natale

Kawata

et al. 2016

Mon. Not. R. Astron. Soc.

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We present a new theoretical population synthesis model (the Galaxy Model) to examine and deal with large amounts of data from surveys of the Milky Way and to decipher the present and past structure and history of our own Galaxy.We assume the Galaxy to consist of a superposition of many composite stellar populations belonging to the thin and thick disks, the stellar halo and the bulge, and to be surrounded by a single dark matter halo component. A global model for the Milky Way's gravitational potential is built up self-consistently with the density profiles from the Poisson equation. In turn, these density profiles are used to generate synthetic probability distribution functions (PDFs) for the distribution of stars in colour-magnitude diagrams (CMDs). Finally, the gravitational potential is used to constrain the stellar kinematics by means of the moment method on a (perturbed)-distribution function. Spiral arms perturb the axisymmetric disk distribution functions in the linear response framework of density-wave theory where we present an analytical formula of the so-called 'reduction factor' using Hypergeometric functions.Finally, we consider an analytical non-axisymmetric model of extinction and an algorithm based on the concept of probability distribution function to handle colour magnitude diagrams with a large number of stars. A genetic algorithm is presented to investigate both the photometric and kinematic parameter space.This galaxy model represents the natural framework to reconstruct the structure of the Milky Way from the heterogeneous data set of surveys such as Gaia-ESO, SEGUE, APOGEE2, RAVE and the Gaia mission.

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“…Fuhrmann (1998), while the thin disk is populated by younger stars. The normalization of the densities of the stellar populations in the solar neighbourhood gives a thick disk fraction of 2-15%, with the lowest values from Gilmore & Reid (1983) and Chen (1997), and the highest from Chen et al (2001) and Soubiran et al (2003). Robin et al (1996) and Buser et al (1999) found values around 6%.…”

Section: Introductionmentioning

confidence: 97%

Elemental abundance trends in the Galactic thin and thick disks as traced by nearby F and G dwarf stars

Bensby

Feltzing

Lundström

2003

A&A

851

119

1,264

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Abstract. Based on spectra from F and G dwarf stars, we present elemental abundance trends in the Galactic thin and thick disks in the metallicity regime −0.8 [Fe/H] +0.4. Our findings can be summarized as follows. 1) Both the thin and the thick disks show smooth and distinct abundance trends that, at sub-solar metallicities, are clearly separated. 2) For the α-elements the thick disk shows signatures of chemical enrichment from SNe type Ia.3) The age of the thick disk sample is in the mean older than the thin disk sample. 4) Kinematically, there exist thick disk stars with super-solar metallicities. Based on these findings, together with other constraints from the literature, we discuss different formation scenarios for the thick disk. We suggest that the currently most likely formation scenario is a violent merger event or a close encounter with a companion galaxy. Based on kinematics the stellar sample was selected to contain stars with high probabilities of belonging either to the thin or to the thick Galactic disk. The total number of stars are 66 of which 21 belong to the thick disk and 45 to the thin disk. The analysis is based on high-resolution spectra with high signal-to-noise (R ∼ 48 000 and S /N 150, respectively) recorded with the FEROS spectrograph on La Silla, Chile. Abundances have been determined for four α-elements (Mg, Si, Ca, and Ti), for four even-nuclei iron peak elements (Cr, Fe, Ni, and Zn), and for the light elements Na and Al, from equivalent width measurements of ∼30 000 spectral lines. An extensive investigation of the atomic parameters, log g f -values in particular, have been performed in order to achieve abundances that are trustworthy. Noteworthy is that we find for Ti good agreement between the abundances from Ti  and Ti . Our solar Ti abundances are in concordance with the standard meteoritic Ti abundance.

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Stellar Population Studies with the SDSS. I. The Vertical Distribution of Stars in the Milky Way

Cited by 351 publications

References 57 publications

A Matched-Filter Analysis of the Tidal Tails of the Globular Cluster Palomar 5

A Matched-Filter Analysis of the Tidal Tails of the Globular Cluster Palomar 5

Spiral arm kinematics for Milky Way stellar populations

Elemental abundance trends in the Galactic thin and thick disks as traced by nearby F and G dwarf stars

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