NGC 2899: An Evolved Bipolar Planetary Nebula

1989 ◽  
Vol 131 ◽  
pp. 179-179
Author(s):  
J. A. López ◽  
L. H. Falcón ◽  
M. T. Ruiz ◽  
M. Roth
Keyword(s):  
Planetary Nebula ◽  
Surface Brightness ◽  
High Surface ◽  
Angular Size ◽  
Minor Axis ◽  
Bipolar Structure ◽  
High Surface Brightness ◽  
Central Object ◽  
Toroidal Geometry

NGC 2899 (PK 277-3°l, He 2-30, RCW 43) is a southern planetary nebula of fairly large angular size (∼2!6 × 1!4) and moderate high surface brightness. Its morphology strongly resembles a loose bipolar structure with conspicuous bright condensations of toroidal geometry placed along the minor axis, on each side of the central object.

Internal Motions in the Planetary Nebula NGC 6543

1968 ◽  
Vol 34 ◽  
pp. 259-266 ◽  
Author(s):  
Guido Münch
Keyword(s):  
Planetary Nebula ◽  
Surface Brightness ◽  
High Surface ◽  
High Surface Brightness ◽  
Ideal Object ◽  
Internal Motions ◽  
Flat Spiral

The planetary nebula NGC 6543 has been described (Curtis, 1918) as “quite irregular, of helical form”. Its high surface brightness and its dimensions (16′′ × 22′′ of arc) make it an ideal object for observation with the multislit technique used by Wilson (1950) to study other planetaries. In fact, had NGC 6543 been accessible to the 100-inch Mount Wilson Coudé, undoubtedly it would have been included in Wilson's survey. The interest in NGC 6543 arises from the fact that no information is available regarding the motions in a planetary nebula with some sort of helical appearance. The obvious question that arises in this respect is whether the nebular material is actually arranged in space on an open helix, rather than in a flat spiral. The related problems of its lifetime and stability also may be elucidated by studying in detail the internal motions.

scholarly journals X-ray Interferometry

2001 ◽  
Vol 205 ◽  
pp. 457-462
Author(s):  
Webster Cash
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Surface Brightness ◽  
High Surface ◽  
X Rays ◽  
High Surface Brightness ◽  
X Ray

X-rays have tremendous potential for imaging at the highest angular resulution. The high surface brightness of many x-ray sources will reveal angular scales heretofore thought unreachable. The short wavelengths make instrumentation compact and baselines short. We discuss how practical x-ray interferometers can be built for astronomy using existing technology. We describe the Maxim Pathfinder and Maxim missions which will achieve 100 and 0.1 micro-arcsecond imaging respectively. The science to be tackled with resolution of up to one million times that of HST will be outlined, with emphasis on eventually imaging the event horizon of a black hole.

scholarly journals A MULTIWAVELENGTH STUDY OF THE HIGH SURFACE BRIGHTNESS HOT SPOT IN PKS 1421–490

2009 ◽  
Vol 695 (1) ◽  
pp. 707-723 ◽  
Author(s):  
L. E. H. Godfrey ◽  
G. V. Bicknell ◽  
J. E. J. Lovell ◽  
D. L. Jauncey ◽  
J. Gelbord ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Hot Spot ◽  
High Surface ◽  
High Surface Brightness

Dark Matter within High Surface Brightness Spiral Galaxies

2003 ◽  
Vol 586 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Thilo Kranz ◽  
Adrianne Slyz ◽  
Hans‐Walter Rix
Keyword(s):  
Dark Matter ◽  
Surface Brightness ◽  
Spiral Galaxies ◽  
High Surface ◽  
High Surface Brightness

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.

Spectral observations of high-surface-brightness galaxies. III

Astrophysics ◽  
1977 ◽  
Vol 12 (2) ◽  
pp. 122-125
Author(s):  
M. A. Arakelyan ◽  
�. A. Dibai ◽  
V. F. Esipov
Keyword(s):  
Surface Brightness ◽  
High Surface ◽  
High Surface Brightness

High dispersion spectra of Planetary Nebulae

1997 ◽  
Vol 180 ◽  
pp. 242-242
Author(s):  
S. Hyung ◽  
L. H. Aller
Keyword(s):  
Plasma Diagnostics ◽  
Surface Brightness ◽  
High Surface ◽  
Planetary Nebulae ◽  
High Dispersion ◽  
Chemical Compositions ◽  
Echelle Spectrograph ◽  
High Surface Brightness ◽  
Low Surface Brightness ◽  
Ngc 7662

Determinations of the plasma diagnostics and chemical compositions of planetary nebulae require ultimately high dispersion spectra. For objects of high surface brightness the Hamilton Echelle Spectrograph at Lick Observatory is satisfactory for the region 3650–10100Å which involves the 168th to 56th echelle orders. For a slit width of 640 μm amounting to 1.15 arcsec at the Coude focus, the actual spectral resolution (FWHM) is about 0.2Å at 8850Å. The length of the slit is chosen as 4.0 arcsec. Hyung (1994) & Aller (1994) describe the observing procedure. Since the Hamilton echelle was designed primarily for star-like sources, it is not useful for extended low surface brightness PN. The earlier observations were obtained with an 800 × 800 chip that did not cover the echelle field, so several settings were needed. Later, we used a slower 2048 × 2048 chip which covered the whole field and was somewhat more efficient at longer wavelengths. The program has been completed and definitive measurements have obtained for NGC 2440, NGC 6543, NGC 6741, NGC 6818, NGC 7026, NGC 7662, and Hu 1-2. All of these PN display particularly rich, interesting spectra. Previously observed and published objects include IC 351, IC 418, IC 2149, IC 4997, NGC 6567, NGC 6572, NGC 6790, NGC 6886, NGC 7009, BD +30 3639, & Hubble 12. NGC 6884 is in press. Additional nebulae which are yet to be discussed are IC 4634, IC 4846, IC 5117, NGC 6210, & NGC 6803.

scholarly journals The σc — Vcirc correlation in high and low surface brightness galaxies

2004 ◽  
Vol 220 ◽  
pp. 339-340 ◽  
Author(s):  
A. Pizzella ◽  
E. Dalla Bontà ◽  
E. M. Corsini ◽  
L. Coccato ◽  
F. Bertola
Keyword(s):  
Surface Brightness ◽  
Velocity Dispersion ◽  
Spiral Galaxies ◽  
High Surface ◽  
Linear Scale ◽  
High Surface Brightness ◽  
Circular Velocity ◽  
Straight Line ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

We investigate the relation between the central velocity dispersion, σc, and the circular velocity, Vcirc, in galaxies. in addition to previously obtained data, we consider an observationally homogeneus sample of 52 high surface brightness and 11 low surface brightness spiral galaxies. We performed a straight line regression analysis in a linear scale, finding a good fit, also for low σc galaxies, always rejected in the previous studies. Low surface brightness galaxies seem to behave differently, showing either higher values of Vcirc or lower values of σc with respect to their high surface brightness counterparts.

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