[Show abstract][Hide abstract] ABSTRACT: Planetary nebulae (PNe) are now well established as probes of galaxy dynamics and as standard candles in distance determinations. Motivated by the need to improve the efficiency of planetary nebulae searches and the speed with which their radial velocities are determined, a dedicated instrument-the Planetary Nebula Spectrograph, or PN.S-has been designed and commissioned at the 4.2 m William Herschel Telescope. The high optical efficiency of the spectrograph results in the detection of typically ~150 PNe in galaxies at the distance of the Virgo Cluster in one night of observations. In the same observation, the radial velocities are obtained with an accuracy of ~20 km s-1.
Full-text · Article · Nov 2002 · Publications of the Astronomical Society of the Pacific
[Show abstract][Hide abstract] ABSTRACT: We report here the successful commissioning of the PN.Spectrograph, the first special-purpose instrument for the measurement of galaxy kinematics through the PN population
Full-text · Article · Aug 2002 · Proceedings of the International Astronomical Union
[Show abstract][Hide abstract] ABSTRACT: Knowledge about the dynamical properties of the halos of early-type
galaxies (S0's and ellipticals) has been slow to progress because of the
dearth of suitable tracers. To address this shortcoming, we have
embarked upon a program to obtain kinematics of planetary nebulae (PNe)
around nearby galaxies, using general-purpose multi-object spectrographs
on 4-8m class telescopes, and using the newly commissioned Planetary
Nebula Spectrograph, a specialized binocular instrument for
counter-dispersed imaging. We present measurements of ~100-200 PN
velocities to large radii around the galaxies NGC 821, NGC 4472, NGC
4486, and NGC 7457. From these, we derive the galaxies' mass
distributions and stellar angular momenta. We compare these to
predictions from cosmological simulations, and to results from globular
cluster system kinematics and X-ray halo constraints. Based on
observations made at the European Southern Observatory, Chile (ESO No.
67.B-0464), and with the William Herschel Telescope operated on the
island of La Palma by the Isaac Newton Group in the Spanish Observatorio
del Roque de los Muchachos of the Instituto de Astrofisica de Canarias.
[Show abstract][Hide abstract] ABSTRACT: Determining the internal kinematics of a galaxy from planetary nebulae (PN) is usually a two-step process in which the candidate
PN are first identified in a target galaxy and then, in a follow-up run, spectra are obtained. We have implemented a new technique
in which two dispersed images at the wavelength of the [O iii] emission line at 5007 are combined to yield positions, magnitudes and velocities of the PN population in a single step.
A reduction in observing time of about a factor of 2 is attainable. We present here the proof-of-principle results.
Preview · Article · Sep 1998 · Monthly Notices of the Royal Astronomical Society