Is a Quasar Nucleus a Star Cluster or a Single Body?

Gudzenko, L. I.; Ozernoy, L. M.; Chertoprud, V. E.

doi:10.1038/215605a0

Cited by 13 publications

(6 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, if these fluctuations of 3C 273 are due to random pulses, the pulse parameters are given directly and simply by the power spectrum. The moments and trend of the data have also been found to be consistent with random shot noise (Terrell and Olsen, 1970). Figure 5 shows random shot noise fluctuations which we generated in a computer, with pulse rate and length similar to those determined from the 3C 273 spectrum, in order to verify our results.…”

Section: •Llililillillllllllllllllllllllllillisupporting

confidence: 64%

“…When the first 2500 days of data, representing mostly interpolation, are truncated, the result shown here is a power spectrum of somewhat less low-frequency power but otherwise similar. The data as averaged by Ozernoy and Chertoprud (1966) give even less low-frequency power, and a possible resonance -with considerably less than 50% certainty. It should be noted that their data are The value of the two-sided power spectrum at this point, when normalized as here, is equal to \/X, where X is the rate of occurrence of the pulses.…”

mentioning

confidence: 90%

“…Smith (1965) found indications of a 13-yr period, more or less sinusoidal, in this record. Gudzenko et al (1967) analyzed the data and found a 9-or 10-yr period, with 99% certainty (or, more recently, 97%). Manwell and Simon (1966) found no evidence of periodicity and stated that the fluctuations could be reproduced by the superposition of about 25 very short outbursts of light per year.…”

mentioning

confidence: 96%

“…. Luminosity data for 3C 273, relative to the average luminosity, L, based on photographic magnitudes averaged over 100-day intervals by Kunkel (1967). Least squares linear trends are shown, both for the full data and for the truncated data .…”

mentioning

confidence: 99%

“…If the first 2500 days of data are omitted as of little reliability, being more interpolation than data, this trend is reduced to 16% per century. The data shown here are as averaged by Kunkel (1967) over 100-day intervals. Smith (1965) found indications of a 13-yr period, more or less sinusoidal, in this record.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Can the Optical Fluctuations of 3C 273 be Random?

Terrell

Olsen

1972

Symp. - Int. Astron. Union

View full text Add to dashboard Cite

Abstract. The fluctuations in optical brightness of the quasi-stellar object 3C 273 have been investiga ted to determine whether the suggested periodicity of ~ 10 yr is supported by the observational data extending over 80 yr. New methods of obtaining information from the power spectrum have been used, and moments and trends have also been investigated. No statistically-supportable evidence has been found in the power spectrum for such a non-random variation. The moments and trends are consistent with random fluctuations. If the observed fluctuations are of shot-noise character, due to random outbursts of light, the individual pulses must occur at the rate of 15± 5 per year and have an average effective length of 3.2± 1 yr. These conclusions were verified by computer-generation and power-spectrum analysis of such random signals. Thus any periodic variation in the brightness of 3C 273, if present, is completely obscured by random fluctuations. The power spectrum, moments, and trend are all consistent with random but long-lasting outbursts of light.Although 3C 273 was not discovered to be a quasi-stellar object until 1963, we fortu nately have an 80-yr record of its optical brightness. It is bright enough at thirteenth magnitude to show up on old sky survey plates extending back to 1887. Harlan Smith and Dorrit Hoffleit (1963), examining these plates, found that 3C273 has been fluctuating in brightness by considerable amounts.

show abstract

Section: •Llililillillllllllllllllllllllllillisupporting

confidence: 64%

mentioning

confidence: 90%

mentioning

confidence: 96%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations