7 papers
The Dearth of Massive, Helium-Rich White Dwarfs in Young Open Star Clusters
Jasonjot Singh Kalirai, Harvey B. Richer, Brad M. S. Hansen +2
Spectra have been obtained of 21 white dwarfs (WDs) in the direction of the young, rich open star cluster NGC 2099. This represents an appreciable fraction (>30%) of the cluster's…
The Initial-Final Mass Relationship: Spectroscopy of White Dwarfs in NGC 2099 (M37)
Jasonjot Singh Kalirai, Harvey B. Richer, David Reitzel +5
We present new observations of very faint white dwarfs (WDs) in the rich open star cluster NGC 2099 (M37). Following deep, wide field imaging of the cluster using CFHT, we have now…
HST Observations of the Main Sequence of M4
H. B. Richer, G. G. Fahlman, J. Brewer +8
This paper presents new results from a photometric study of the main-sequence stars in M4, the closest globular cluster to the sun. Multi-field, multi-epoch observations at approxi…
Searching for the Galactic Dark Matter
Harvey B. Richer
A straightforward interpretation of the MACHO microlensing results in the direction of the Magellanic Clouds suggests that an important fraction of the baryonic dark matter compone…
If the MACHOs are Old White Dwarfs
Harvey B. Richer
The microlensing experiments in the direction of the LMC seem to be indicating that about 60% of the dark matter in the Galactic halo is tied up in objects whose masses are about h…
HST Photometry of the Globular Cluster M4
Rodrigo A. Ibata, Harvey B. Richer, Gregory G. Fahlman +5
This paper presents a detailed description of the acquisition and processing of a large body of imaging data for three fields in the globular cluster M4 taken with the Wide Field a…