The Galactic bulge and halo

Morrison, Heather; Harding, Paul

doi:10.1086/133267

Cited by 16 publications

(14 citation statements)

References 27 publications

(43 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Whereas latetype giants which lie up to large distances relative to the Sun or up to large z-heights from the galactic plane have multi-modal metallicity distribution. However, the weighted mean metal-abundances of late-type giants in our sample is < [Fe/H] >= −0.7 dex, rather close to the one claimed by Morrison & Harding (1993), i.e. −0.8 dex, who investigated only the K giants in two square degree field almost symmetric to ours relative to the galactic plane (l = 350…”

Section: Resultssupporting

confidence: 89%

Analysis of UBV photometry in selected area 133

et al. 2004

View full text Add to dashboard Cite

Abstract. We interpret the de-reddened UBV data for the field SA 133 to deduce the stellar density and metallicity distribution functions. The logarithmic local space density for giants, D * (0) = 6.40, and the agreement of the luminosity function for dwarfs and sub-giants with the one of Hipparcos confirms the empirical method used for their separation. The metallicity distribution for dwarfs gives a narrow peak at [F e/H] = +0.13 dex, due to apparently bright limiting magnitude, Vo = 16.5, whereas late-type giants extending up to z ∼ 4.5 kpc from the galactic plane have a multimodal distribution.

show abstract

Section: Resultssupporting

confidence: 89%

Analysis of UBV photometry in selected area 133

et al. 2004

View full text Add to dashboard Cite

show abstract

“…The existence of different classes of globular clusters in connection with both spatial extent, metal content, systematic rotation, and velocity dispersion, gives additional support to the idea of a monolithic collapse process, followed by accretion via the disruption of satellite systems (see e.g., Da Costa and Armandroff 1995). The existence of different classes of bulge populations (Morrison and Harding 1993) may lead to the same conclusion.…”

Section: The Abundance Distribution Among G Dwarfs In Geneml Is Appromentioning

confidence: 68%

The G‐dwarf problem in the solar neighbourhood: a Lagrangian picture

Caimmi

1997

Astron Nachr

View full text Add to dashboard Cite

Recent data on the empirical metallicity distribution of G dwarfs in the disk solar neighbourhood are fitted in two different ways. We use an extended Poisson distribution in the limit where the probability of star formation is small, and a Gauss distribution in the limit where a large number of physical variables is required to determine stellar metal abundance. Both are found to reproduce the data at the same (acceptable) extent, with a slight preference for the former. The empirical, differential metallicity distribution of G dwarfs in the disk solar neighbourhood is compared with its theoretical counterpart, in the picture of a closed, comoving model of chemical evolution. The limits of the currently used infall models are discussed and a scenario of galactic formation and evolution is presented. The Galactic history is thought as made of two main phases: contraction (which produces the extended component) and equilibrium (which gives the disk). In this view, the stars observed within the solar cylinder did not necessarily arise from the primordial gas which later collapsed into the disk solar neighbourhood. It is found that the G-dwarf problem is strongly alleviated, with the possible exception of the low-metallicity and high-metallicity tail of the distribution. The best choice of parameters implies: (i) a metal yield in the contraction phase which is larger by a factor of about 5 with respect to the equilibrium phase; (ii) a model halo mass fraction of about 0.3; (iii) a model disk mass fraction of about 0.6. I t provides additional support to the idea of a generalized Schmidt star formation law, which is different in different phases of evolution. The model, cumulative, G-dwarf metallicity distribution in the disk solar neighbourhood is found to predict too many low-metallicity stars with respect to its empirical counterpart, related to a Poissonian or Gaussian fit. The main reasons for the occurrence of a G-dwarf problem are discussed. Finally, a stochastic process of star formation, related to a Poisson distribution, is briefly outlined.

show abstract

“…The Galactic bulge extends over a region of galactic longitude l ≃±15° and galactic latitude b ≃±10°; dimensions ∼2 kpc toward and ∼1.5 kpc perpendicular the Galactic plane, respectively (Weiland et al 1993). In total, the bulge contains about 10 11 stars of Population II as well as gas (∼10 6 M ⊙ ) and dust; mass ∼100 times less than the mass of the gas (Morison & Harding 1993). It is generally accepted that a large number of PNe exist in the Galactic bulge, but because of the excessive interstellar extinction, only a small number of them (less than 500) have been discovered (Köppen & Vergely 1998; Parker et al 2001b).…”

Section: Introductionmentioning

confidence: 99%

New planetary nebulae in the Galactic bulge region with l > 0 - I. Discovery method and first results

Boumis¹,

Paleologou²,

Mavromatakis³

et al. 2003

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We present the first results of an [O iii] 5007 Å interference filter survey for planetary nebulae (PNe) in the Galactic bulge. Covering (at first) the 66 per cent of the survey area, we detected a total of 90 objects, including 25 new PNe, 57 known PNe and eight known PNe candidates. Deep Hα+[N ii] CCD images have been obtained as well as low‐resolution spectra for the newly discovered PNe. Their spectral signature suggests that the detected emission originates from a photoionized nebula. In addition, absolute line fluxes have been measured and the electron densities are given. Accurate optical positions and optical diameters have also been determined.

show abstract

The Galactic bulge and halo

Cited by 16 publications

References 27 publications

Analysis of UBV photometry in selected area 133

Analysis of UBV photometry in selected area 133

The G‐dwarf problem in the solar neighbourhood: a Lagrangian picture

New planetary nebulae in the Galactic bulge region with l > 0 - I. Discovery method and first results

Contact Info

Product

Resources

About