scholarly journals Four New Evolved Planetary Nebulae

1993 ◽  
Vol 155 ◽  
pp. 34-34
Author(s):  
S. Tamura ◽  
R. Weinberger
Keyword(s):  
Planetary Nebula ◽  
Surface Brightness ◽  
Planetary Nebulae ◽  
Advanced Stage ◽  
Spectroscopic Observations ◽  
Sky Survey ◽  
Low Surface Brightness

While examining Palomar Observatory Sky Survey prints for various purposes, we came upon a number of hitherto uncatalogued nebulous objects, all of them of low surface brightness. Four of them are considered by us as new planetary nebula candidates due to their morphology. For the brightest one of them, spectroscopic observations were carried out with the Cassegrain spectrograph attached to the 74-inch telescope of the Okayama Astrophysical Observatory: this object (1 = 65.49°, b = +3.18°) is clearly confirmed as a planetary nebula and obviously is in an advanced stage in its evolution; in Fig. 1, a spectrum of it is shown.

scholarly journals PFP 1: A Large Planetary Nebula Caught in the First Stages of ISM Interaction

2004 ◽  
Vol 21 (3) ◽  
pp. 334-343 ◽  
Author(s):  
Mark J. Pierce ◽  
David J. Frew ◽  
Quentin A. Parker ◽  
Joachim Köppen
Keyword(s):  
Survey Data ◽  
Planetary Nebula ◽  
Surface Brightness ◽  
Central Star ◽  
The North ◽  
Sky Survey ◽  
Solar Composition ◽  
Low Surface Brightness ◽  
Imaging And Spectroscopy ◽  
Highly Evolved

AbstractThis paper presents (Hα + [Nii]) imaging and spectroscopy of a previously unknown, highly evolved planetary nebula of low excitation which is in the first stages of an interaction with the interstellar medium (ISM). It was discovered serendipitously from AAO/UKST Hα Survey images as part of a project to exploit the survey data and has evaded detection by previous surveys due to its very low surface brightness. It is a remarkable hollow-sphere planetary nebula, some 19´ across, making it one of the largest examples of its type. We estimate a radius of 1.5 pc and a distance of 550 pc as derived from a new Hα surface brightness–radius relation. PFP 1 has near-perfect circular symmetry, broken only at the north-western edge which is coupled with significantly increased (Hα + [Nii]) intensity, both of which provide evidence for an interaction with the ISM. We find a near solar composition for this object with possibly enhanced He and N abundances. A blue central star candidate has been identified from the SuperCosmos Sky Survey data.

scholarly journals Surveys of Low Surface Brightness Galaxies by 4415 Films

1994 ◽  
Vol 161 ◽  
pp. 541-544
Author(s):  
S. Phillipps ◽  
Q.A. Parker
Keyword(s):  
Surface Brightness ◽  
Signal To Noise ◽  
The Past ◽  
Cluster Area ◽  
Sky Survey ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

During the past few years there have been a number of surveys for low surface brightness galaxies (LSBGs). Searches using both photographic and CCD data have shown that LSBGs are actually very numerous (Impey, Bothun & Malin 1987; Irwin et al. 1990). However, they are seriously biased against in any random sky survey, and even in a cluster area there are inherent size and signal-to-noise problems. The number of objects we can detect are therefore limited in two ways.

scholarly journals Kinematics of Planetary Nebulae in M51's Tidal Tail

2003 ◽  
Vol 209 ◽  
pp. 633-634
Author(s):  
John J. Feldmeier ◽  
J. Christopher Mihos ◽  
Patrick R. Durrell ◽  
Robin Ciardullo ◽  
George H. Jacoby
Keyword(s):  
Surface Brightness ◽  
Numerical Models ◽  
Planetary Nebulae ◽  
Tidal Tail ◽  
Low Surface Brightness ◽  
Galaxy Interaction ◽  
Self Consistent ◽  
The Galaxy ◽  
Interacting Systems ◽  
Kinematic Properties

The galaxy pair NGC 5194/95 (M51) is one of the closest and best known interacting systems. Despite its notoriety, however, many of its features are not well studied. Extending westward from NGC 5195 is a low surface brightness tidal tail, which can only be seen in deep broadband exposures. Our previous [O III] λ5007 planetary nebulae (PN) survey of M51 recovered this tidal tail, and presented us with a opportunity to study the kinematics of a galaxy interaction in progress. We report the results of a spectroscopy survey of the PN, aimed at determining their kinematic properties. We then use these data to constrain new self-consistent numerical models of the system.

scholarly journals The Nature of the Hot Companion of the G8 IV Nucleus of Abell 35

1989 ◽  
Vol 131 ◽  
pp. 314-314
Author(s):  
Michael Grewing ◽  
Luciana Bianchi
Keyword(s):  
Spectroscopic Study ◽  
Small Group ◽  
Planetary Nebula ◽  
Surface Brightness ◽  
Central Object ◽  
Low Surface Brightness ◽  
Ubvri Photometry ◽  
Colour Indices

The nucleus of the large, low surface brightness planetary nebula Abell 35 (Abell 1966) belongs to the small group of objects which are known to have a binary nucleus. From his photometric and spectroscopic study of the object, Jacoby (1981, Astrophys. J. 244,903) found the star SAO 181201, a G8 IV star, to be located near the apex of the parabolic region of enhanced [O III] emision which is completelely absent in H∝. The G8 IV star can clearly not be the ionising source for this nebulosity nor the larger scale nebulosity of the PN proper. Jacoby concluded that the central object must be a binary and suggested a hot subdwarf as the second component, which is masked in the optical by the bright SAO star. This interpretation is supported by the analysis of the DDO and UBVRI photometry, which shows that the observed colour indices can be fitted if one assumes a 50.000 K blackbody companion.

scholarly journals The Low Surface Brightness Galaxy HIPASS1126-72

1999 ◽  
Vol 171 ◽  
pp. 204-206
Author(s):  
Virginia Kilborn ◽  
Erwin de Blok ◽  
Lister Staveley-Smith ◽  
Rachel Webster
Keyword(s):  
Surface Brightness ◽  
Neutral Hydrogen ◽  
Sky Survey ◽  
Low Surface Brightness ◽  
The Galaxy

AbstractThe low surface brightness galaxy HIPASS1126-72 was detected in the HI Parkes All Sky Survey (HIPASS). The galaxy was previously listed in the Southern Galaxy Catalogue under the name SGC1124.87221. This galaxy represents a class of galaxies that we will readily detect in the HIPASS survey, which have low surface brightness in the optical, but are easily detectable in neutral hydrogen.

scholarly journals An imaging and spectroscopic survey of the Abell Planetary Nebulae

1997 ◽  
Vol 180 ◽  
pp. 287-287
Author(s):  
N. A. Walton ◽  
J. R. Walsh ◽  
G. Dudziak
Keyword(s):  
White Dwarf ◽  
Surface Brightness ◽  
Planetary Nebulae ◽  
Central Star ◽  
Large Size ◽  
Low Surface Brightness ◽  
Thermal Pulses ◽  
Central Stars

The Abell catalogue of planetary nebulae (PN) are distinguished by their large size, low surface brightness and generally faint central stars. They are thought to be old PN approaching the White Dwarf cooling track. A number have evidence for late thermal pulses (H-poor ejecta near the central star, e.g. A78) and binary central stars.

scholarly journals Spectroscopic Observations of Comet Kohoutek (1973f) II

1976 ◽  
Vol 25 (Part1) ◽  
pp. 184-198
Author(s):  
Piero Benvenuti
Keyword(s):  
Surface Brightness ◽  
Full Length ◽  
Image Tube ◽  
First Order ◽  
Spectroscopic Observations ◽  
Low Surface Brightness ◽  
Main Instrument

Systematic spectroscopic observations of comet Kohoutek (1973f) were scheduled at the Asiago Astrophysical Observatory, starting from the end of October. The nebular spectrograph for the newtonian focus of the 122 cm reflector was selected as main instrument for this research. This spectrograph, described by Bertola (1970), is followed by a WL-30677 image tube and it is particularly designed for extended objects of low surface brightness. Two gratings were used giving a dispersion in the first order of 125 Å mm-1 and 240 Å mm-1 respectively. The scale normal to the dispersion is 127 arcsec mm-1 and the full length of the slit is 8 arcmin.

scholarly journals Tidal Remnants and Intergalactic H II Regions

2004 ◽  
Vol 217 ◽  
pp. 486-491 ◽  
Author(s):  
Tom Oosterloo ◽  
Raffaella Morganti ◽  
Elaine M. Sadler ◽  
Annette Ferguson ◽  
Thijs van der Hulst ◽  
...  
Keyword(s):  
Star Formation ◽  
Surface Brightness ◽  
Small Scale ◽  
H Ii Regions ◽  
Tidal Disruption ◽  
Tidal Interactions ◽  
Sky Survey ◽  
Low Surface Brightness ◽  
Intergalactic Space ◽  
Star Formation Regions

We report the discovery of two small intergalactic H II regions in the loose group of galaxies around the field elliptical NGC 1490. The H II regions are located at least 100 kpc from any optical galaxy but are associated with a number of large H I clouds that are lying along an arc 500 kpc in length and that have no optical counterpart on the Digital Sky Survey. The sum of the H I masses of the clouds is almost 1010M⊙ and the largest H I cloud is about 100 kpc in size. Deep optical imaging reveals a very low surface brightness counterpart to this largest H I cloud, making this one of the H I richest optical galaxies known (MHI/LV ~ 200). Spectroscopy of the H II regions indicates that the abundance in these H II regions is only slightly sub-solar, excluding a primordial origin of the H I clouds. The H I clouds are perhaps remnants resulting from the tidal disruption of a reasonably sized galaxy, probably quite some time ago, by the loose group to which NGC 1490 belongs. Alternatively, they are remnants of the merger that created the field elliptical NGC 1490. The isolated H II regions show that star formation on a very small scale can occur in intergalactic space in gas drawn from galaxies by tidal interactions. Many such intergalactic small star formation regions may exist near tidally interacting galaxies.

scholarly journals Stellar Over-Densities in the Outer Halo of the Milky Way

2010 ◽  
Vol 27 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Stefan C. Keller
Keyword(s):  
Surface Brightness ◽  
Dwarf Galaxy ◽  
Local Density ◽  
Spatial Scales ◽  
Sloan Digital Sky Survey ◽  
Tidal Disruption ◽  
Giant Stars ◽  
Sky Survey ◽  
Low Surface Brightness ◽  
Model Predictions

AbstractThis study presents a tomographic survey of a subset of the outer halo (10–40 kpc) drawn from the Sloan Digital Sky Survey Data Release 6. Halo substructure on spatial scales of >3 degrees is revealed as an excess in the local density of sub-giant stars. With an appropriate assumption of a model stellar isochrone it is possible for us to then derive distances to the sub-giant population. We describe three new candidate halo substructures; the 160- and 180-degree over-densities (at distances of 17 and 19 kpc respectively and radii of 1.3 and 1.5 kpc respectively) and an extended feature at 28 kpc that covers at least 162 deg2, the Virgo Equatorial Stream. In addition, we recover the Sagittarius dwarf galaxy (Sgr) leading-arm material and the Virgo Over-Density.The derived distances, together with the number of sub-giant stars associated with each substructure, enables us to derive the integrated luminosity for the features. The tenuous, low surface brightness of the features strongly suggests an origin from the tidal disruption of an accreted galaxy or galaxies. Given the dominance of the tidal debris of Sgr in this region of the sky we investigate if our observations can be accommodated by tidal disruption models for Sgr. The clear discordance between observations and model predictions for known Sgr features means it is difficult to tell unambiguously if the new substructures are related to Sgr or not. Radial velocities in the stellar over-densities will be critical in establishing their origins.

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