scholarly journals Optical Variability of Twenty-Two Quasi-Stellar Objects

1972 ◽  
Vol 44 ◽  
pp. 171-178 ◽  
Author(s):  
R. J. Angione ◽  
H. J. Smith
Keyword(s):  
Large Amplitude ◽  
Small Amplitude ◽  
Secular Trends ◽  
Apparent Magnitude ◽  
Optical Variability ◽  
Stellar Objects ◽  
Light Fluctuations ◽  
Quasi Stellar Objects ◽  
One Year

Light fluctuations have been found in all 22 QSOs studied by measurement of plates from the Harvard collection, which cover the last eighty years. The conclusions of this study are: (i) There appear to be at least three general classes of variation: (a) erratic, small-amplitude variations, (b) erratic, large-amplitude variations, and (c) slow quasi-periodic variations, e.g. as in 3C 273; (ii) No significant differences were detected between the rates of rise and decline of luminosity; (iii) Definite secular trends over at least 50 years were found in 5 QSOs; (iv) No simple clearcut periods greater than one year have been found; (v) There may be a trend of decreasing amplitude of fluctuations in apparent magnitude with increasing luminosity.

scholarly journals Radio Emission from Compact Objects

1972 ◽  
Vol 44 ◽  
pp. 190-213
Author(s):  
K. I. Kellermann
Keyword(s):  
Angular Size ◽  
Brightness Distribution ◽  
Compact Objects ◽  
Radio Sources ◽  
Stellar Objects ◽  
Large Intensity ◽  
Quasi Stellar Objects ◽  
One Year ◽  
Ngc 1275 ◽  
Compact Sources

Compact radio stars are associated with both galaxies and quasi-stellar objects; and there appears to be no way to distinguish between the radio galaxies and the quasi-stellar radio sources from their radio properties alone.The compact radio sources are opaque at the longer radio wavelengths and have spectra that are either peaked or complex. They have a complex brightness distribution and often contain components less than 0.001 arc sec in size.Many of the compact sources show large intensity variations and in NGC 1275 there is evidence for a change in the angular size during one year.

scholarly journals Statistical Properties of QSOs

1972 ◽  
Vol 44 ◽  
pp. 453-457
Author(s):  
A. Braccesi
Keyword(s):  
Optical Properties ◽  
Radio Emission ◽  
Statistical Properties ◽  
Optical Variability ◽  
Stellar Objects ◽  
Luminosity Functions ◽  
Quasi Stellar Objects

Counts of quasi-stellar objects selected by their optical properties imply evolutionary properties similar to those found by examining the radio-selected objects. The optical luminosity functions of the 3CR and optically-selected quasi-stellar objects are compared. Data on the radio emission and optical variability of the optically-selected sample are presented.

On nearly-commensurable periods in the restricted problem of three bodies, with calculations of the long-period variations in the interior 2:1 case

1966 ◽  
Vol 25 ◽  
pp. 197-222 ◽  
Author(s):  
P. J. Message
Keyword(s):  
Periodic Solution ◽  
Periodic Solutions ◽  
Large Amplitude ◽  
Restricted Problem ◽  
Small Amplitude ◽  
Minor Planets ◽  
Long Period ◽  
Numerical Integrations ◽  
Period Variations ◽  
The Mean

An analytical discussion of that case of motion in the restricted problem, in which the mean motions of the infinitesimal, and smaller-massed, bodies about the larger one are nearly in the ratio of two small integers displays the existence of a series of periodic solutions which, for commensurabilities of the typep+ 1:p, includes solutions of Poincaré'sdeuxième sortewhen the commensurability is very close, and of thepremière sortewhen it is less close. A linear treatment of the long-period variations of the elements, valid for motions in which the elements remain close to a particular periodic solution of this type, shows the continuity of near-commensurable motion with other motion, and some of the properties of long-period librations of small amplitude.To extend the investigation to other types of motion near commensurability, numerical integrations of the equations for the long-period variations of the elements were carried out for the 2:1 interior case (of which the planet 108 “Hecuba” is an example) to survey those motions in which the eccentricity takes values less than 0·1. An investigation of the effect of the large amplitude perturbations near commensurability on a distribution of minor planets, which is originally uniform over mean motion, shows a “draining off” effect from the vicinity of exact commensurability of a magnitude large enough to account for the observed gap in the distribution at the 2:1 commensurability.

1497-P: Secular Trends in Incidence and One-Year Mortality Rates of Lower Extremity Amputation in People with Diabetes in Hong Kong between 2001 and 2016

Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 1497-P
Author(s):  
HONGJIANG WU ◽  
AIMIN YANG ◽  
ERIC S. LAU ◽  
RONALD C. MA ◽  
ALICE P. KONG ◽  
...  
Keyword(s):  
Hong Kong ◽  
Lower Extremity ◽  
Mortality Rates ◽  
Secular Trends ◽  
Lower Extremity Amputation ◽  
One Year ◽  
Extremity Amputation

The properties of the dusty inner regions of nearby QSOs

2019 ◽  
Vol 15 (S356) ◽  
pp. 95-95
Author(s):  
Itziar Aretxaga
Keyword(s):  
Star Formation ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Stellar Objects ◽  
X Ray ◽  
Mir Spectroscopy ◽  
Polycyclic Aromatic ◽  
Quasi Stellar Objects

AbstractWe present MIR spectroscopy and photometry obtained with CanariCam on the 10.4 m Gran Telescopio CANARIAS for a sample of 20 nearby, MIR bright and X-ray luminous quasi-stellar objects (QSOs). We find that for the majority of QSOs the MIR emission is unresolved at angular scales ∼0.3 arcsec. We derive the properties of the dusti tori that surround the nucleus based on these observations and find significant differences in the parameters compared with a sample of Seyfert 1 and 2 nuclei. We also find evidence for polycyclic aromatic hydrocarbon (PAH) features in the spectra, indicative of star formation, more centrally peaked (on scales of a few hundred pc) than previously believed.

scholarly journals Classification of Compact Objects: QSS, QSOs, N-Type and Compact Galaxies, Seyfert and Galactic Nuclei

1972 ◽  
Vol 44 ◽  
pp. 97-103
Author(s):  
W. W. Morgan
Keyword(s):  
Galactic Nuclei ◽  
Seyfert Galaxy ◽  
Classification Criteria ◽  
Compact Objects ◽  
Stellar Objects ◽  
Quasi Stellar Objects ◽  
Compact Galaxies

Some methods currently in use for the classification of the optical forms of the ‘compact’ galaxies and quasi-stellar objects are reviewed. It is shown that the category ‘Seyfert Galaxy’ is basically a spectroscopic (rather than a form) classification.An optical form-classification is described which is, in principle, identical with published classification criteria for QSO, N-type, and compact objects. The importance of maintaining rigid form-standards is emphasized.

On the Space Distribution of Identified Quasi-stellar Objects and Radiogalaxies

Nature ◽  
1967 ◽  
Vol 216 (5113) ◽  
pp. 351-352 ◽  
Author(s):  
G. R. BURBIDGE ◽  
F. HOYLE
Keyword(s):  
Space Distribution ◽  
Stellar Objects ◽  
Quasi Stellar Objects

Nature of strong radio emission from quasi-stellar objects

1964 ◽  
Vol 9 (2) ◽  
pp. 138-139 ◽  
Author(s):  
L. Gold ◽  
J.W. Moffat
Keyword(s):  
Radio Emission ◽  
Stellar Objects ◽  
Quasi Stellar Objects
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