Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “GRAVITATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 973 records · Page 54Linked to original sources
PubMed2000

The Optical Gravitational Lensing Experiment: Red Clump Stars as a Distance Indicator.

We present relation of the mean I-band brightness of red clump stars on metallicity. Red clump stars were proposed to be a very attractive standard candle for distance determination. The calibration is based on 284 nearby red giant stars whose high-quality spectra made it possible to determine accurate individual metal abundances. High-quality parallaxes (sigmapi&solm0;pi<10%) and photometry of these very bright stars come from Hipparcos measurements. Metallicity of the sample covers a large range: -0.6 dex<&sqbl0;Fe&solm0;H&sqbr0;<+0.2 dex. We find a weak dependence of the mean I-band brightness on metallicity ( approximately 0.13 mag dex-1). What is more important, the range of metallicity of the Hipparcos sample partially overlaps with metallicity of field giants in the LMC, thus making it possible to determine the distance to the LMC by almost direct comparison of brightness of the local Hipparcos red clump giants with that of LMC stars. Photometry of field red clump giants in nine low-extinction fields of the LMC halo collected during the OGLE II microlensing survey compared with the Hipparcos red clump stars data yields the distance modulus to the LMC: &parl0;m-M&parr0;LMC=18.24+/-0.08 mag.

Journal Article↗
PubMed2000

Weak Gravitational Lensing by the Nearby Cluster Abell 3667.

We present two weak lensing reconstructions of the nearby (zcl=0.055) merging cluster Abell 3667, based on observations taken approximately 1 yr apart under different seeing conditions. This is the lowest redshift cluster with a weak lensing mass reconstruction to date. The reproducibility of features in the two mass maps demonstrates that weak lensing studies of low-redshift clusters are feasible. These data constitute the first results from an X-ray luminosity-selected weak lensing survey of 19 low-redshift (z<0.1) southern clusters.

Journal Article↗