We report the results of a photometric and spectroscopic survey for planetary nebulae (PNs) over the entire body of the Local Group spiral galaxy M33. We use our sample of 152 PNs to show that the bright end of the galaxy's [OIII]{lambda}5007 planetary nebula luminosity function (PNLF) has the same sharp cutoff seen in other galaxies.
We have examined central stars of planetary nebulae and symbiotic stars found in the MACHO Galactic bulge database to look for variability. We found four central stars of planetary nebulae and eight symbiotic stars that show variability. We examine the variability and the nature of these objects in detail, as well as reporting on the objects that we did not find to be variable.
We report on observations of four early-type galaxies performed with the Rutgers Fabry-Perot in order to search for planetary nebulae (PNe) in these systems. The aim is to use the PNe as kinematic tracers of the galaxy potential. We describe our data reduction and analysis procedure and show that the proper calibration of our detection statistic is crucial in getting down to our limiting magnitude of m_5007_=26.1. In the case of the two Leo galaxies, we find moderately sized samples: 54 PNe in NGC 3379 and 50 PNe in NGC 3384; NGC 4636 (two PNe) and NGC 1549 (six PNe) are included for completeness. We present our samples in tabular form, as well as the spectrum for each PN.
In order to construct a sample of planetary nebulae (PNe) unbiased by dust extinction, we first selected the 1358 sources in the IRAS Point Source Catalog north of J2000 declination DE=-40{deg} having measured S(25{mu}m)>=1 Jy and colors characteristic of PNe: detections or upper limits consistent with both S(12{mu}m)<=0.35S(25{mu}m) and S(25{mu}m)>=0.35S(60{mu}m). The majority are radio-quiet contaminating sources such as asymptotic giant branch stars. Free-free emission from genuine PNe should make them radio sources. The 1.4 GHz NRAO VLA Sky Survey (NVSS) images and source catalog were used to reject radio-quiet mid-infrared sources. We identified 454 IRAS sources with radio sources brighter than S~2.5 mJy/beam (equivalent to T~0.8K in the 45" FHWM NVSS beam) by positional coincidence. They comprise 332 known PNe in the Strasbourg-ESO Catalogue of Galactic Planetary Nebulae and 122 candidate PNe, most of which lie at very low Galactic latitudes. Exploratory optical spectroscopic observations suggest that most of these candidates are indeed PNe optically dimmed by dust extinction, although some contamination remains from H II regions, Seyfert galaxies, etc. Furthermore, the NVSS failed to detect only 4% of the known PNe in our infrared sample. Thus it appears that radio selection can greatly improve the reliability of PN candidate samples without sacrificing completeness.
We present an atlas of more than one hundred original images of planetary nebulae (PNe). These images were taken in a narrow-band filter centred on the nebular emission of the [NII] during several observing campaigns using two moderate-aperture telescopes, at the Complejo Astronomico El Leoncito (CASLEO), and the Estacion Astrofisica de Bosque Alegre (EABA), both in Argentina. The data provided by this atlas represent one of the most extensive image surveys of PNe in [NII]. We compare the new images with those available in the literature, and briefly describe all cases in which our [NII] images reveal new and interesting structures.
We surveyed the central 4x4 degrees of the Galactic center for planetary nebulae in the light of [S III] {lambda}9532 and found 94 PNe that were not previously known, plus 3 that were previously identified as possible candidates. For 63 of these 97 objects, we obtained spectra that are consistent with highly reddened PN while the other 34 could not be recovered spectroscopically and remain unverified. Of the 94 candidates, 54 and 57 were detected via radio at 3 and 6cm, respectively. An additional 20 PNe candidates were found during follow-up H{alpha} imaging but have not yet been verified spectroscopically. Based on the properties of IRAS sources in this region of the Galaxy, and on the total luminosity of the Galactic bulge, the expected number of PNe is 250, only 50% more than the 160 PNe candidates now known. Thus, surveys for PNe in the bulge are approximately two-thirds complete with the remainder likely hidden behind dust.
We present new Planetary Nebula Spectrograph observations of the ordinary elliptical galaxy NGC 4494, resulting in positions and velocities of 255 planetary nebulae out to seven effective radii (25kpc). We also present new wide-field surface photometry from MMT/Megacam, and long-slit stellar kinematics from VLT/FORS2.
We apply a method, described in Gorny et al. (1997, Cat. <J/A+A/318/256>), to derive the masses of 125 central stars of planetary nebulae (PN). This method is self-consistent and distance-independent. It requires the knowledge of the nebular H{beta} fluxes, angular radii and expansion velocities, as well as the stellar visual magnitudes. This method is based on a simple model for the evolution of planetary nebulae, in which the central stars evolve according to the theoretical models of Bloecker (1995, Cat. <J/A+A/299/755>) and Schoenberner (1983ApJ...272..708S). The results are dependent on the assumed total nebular mass. Nevertheless, for any reasonable total nebular mass distribution, we find that the range in planetary nebulae central star masses is very restricted: more than 80% of the objects have a central star mass between 0.55 and 0.65M_{sun}_. We show how to convert, in this mass range, the observed PN central star mass distribution into a zero-age post-AGB star mass distribution.
The table lists the heliocentric radial velocities for planetary nebulae in the direction of the Galactic bulge. The accuracy is about 2km/s. The measurements were made in June and July 1993, using the ESO CAT with spectral resolution of 30000-60000. Halpha, [NII] 6548 and 6584 and [O III] 5007 were observed.
