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 ◽  
...  
2001 ◽  
Vol 205 ◽  
pp. 457-462
Author(s):  
Webster Cash

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.


1989 ◽  
Vol 131 ◽  
pp. 179-179
Author(s):  
J. A. López ◽  
L. H. Falcón ◽  
M. T. Ruiz ◽  
M. Roth

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.


2003 ◽  
Vol 586 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Thilo Kranz ◽  
Adrianne Slyz ◽  
Hans‐Walter Rix

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

1997 ◽  
Vol 180 ◽  
pp. 242-242
Author(s):  
S. Hyung ◽  
L. H. Aller

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.


2004 ◽  
Vol 220 ◽  
pp. 339-340 ◽  
Author(s):  
A. Pizzella ◽  
E. Dalla Bontà ◽  
E. M. Corsini ◽  
L. Coccato ◽  
F. Bertola

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.


Astrophysics ◽  
1976 ◽  
Vol 11 (1) ◽  
pp. 8-11 ◽  
Author(s):  
M. A. Arakelyan ◽  
�. A. Dibai ◽  
V. F. Esipov

Sign in / Sign up

Export Citation Format

Share Document