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M. B. Bell

Publications and source records attributed to M. B. Bell.

At least 19 recordsLinked to original sources
arXiv2013

More Evidence for an Oscillation Superimposed on the Hubble Flow

In a recent investigation evidence was presented for a low-level sinusoidal oscillation superimposed on top of the Hubble flow. This oscillation was in V$_{CMB}$, in a sample of type Ia Supernovae sources with accurate distances, and it was found to have a wavelength close to 40 Mpc. It became easily visible after the removal of several previously identified discrete velocity components. Its amplitude like that of the Hubble velocity showed an increase with distance, as would be expected for a constant-amplitude space oscillation. Here we report that this oscillation is also present in distance clumping in these sources, with the same wavelength, but in phase quadrature. The discrete velocity components do not play a role in detecting the distance clumping wavelength. Assuming that time proceeds from high cosmological redshift to low, the blue-shifted velocity peaks, which represent the contraction stage of the velocity oscillation, then lead the density peaks. With the discrete velocity components removed we also find evidence for at least one other, weaker velocity oscillation. It is found to have a wavelength similar to one reported in density clumping by previous investigators. In those cases the source samples were much larger.

astro-ph.CO↗
arXiv2012

On The Depolarization Asymmetry Seen in Giant Radio Lobes

The depolarization asymmetry seen in double-lobed radio sources, referred to as the Laing-Garrington (L-G) effect where more rapid depolarization is seen in the lobe with no visible jet as the wavelength increases, can be explained either by internal differences between the two lobes, or by an external Faraday screen that lies in front of only the depolarized lobe. If the jet one-sidedness is due to relativistic beaming the depolarization asymmetry must be due to an intervening Faraday screen. If it is intrinsic the depolarization asymmetry must be related to internal differences in the lobes. We assume in this paper that the speed in the outer jet of several Fanaroff-Riley Class 1 (FRI) sources exhibiting the L-G effect is close to the 0.1c reported by several other investigators. For these sources we find that the jet one-sidedness cannot be explained by beaming and therefore must be intrinsic. In these FRI sources the L-G effect must be due to differences that originate inside the lobes themselves. Although it is not known if the flow in the outer jets of FRII sources also slows to this speed it is suggested that the explanation of the L-G effect is likely to be the same in both types. This argument is strengthened by the recent evidence that FRII galaxies have very large viewing angles, which in turn implies that the L-G model cannot work regardless of the jet velocity. It may therefore be too soon to completely rule out internal depolarization in the lobes as the true explanation for the L-G effect.

astro-ph.CO↗
arXiv2012

More on the Narrowing of Impact Broadened Radio Recombination Lines at High Principal Quantum Number

Recently Alexander and Gulyaev have suggested that the apparent decrease in impact broadening of radio recombination lines seen at high principal quantum number n may be a product of the data reduction process, possibly resulting from the presence of noise on the telescope spectra that is not present on the calculated comparison spectra. This is an interesting proposal. However, there are serious problems with their analysis that need to be pointed out. Perhaps the most important of these is the fact that for principal quantum numbers below n = 200, where the widths are not in question, their processed generated profile widths do not fit the widths of the processed lines obtained at the telescope. After processing, the halfwidths of the generated and telescope profiles must agree below n = 200 if we are to believe that the processed generated linewidths above n = 200 are meaningful. Theirs do not. Furthermore, we find that after applying the linewidth reduction factors found by Alexander and Gulyaev for their noise added profiles to our generated profiles to simulate their noise adding effect, the processed widths we obtain still do not come close to explaining the narrowing seen in the telescope lines for n values in the range 200 < n < 250. It is concluded that what is needed to solve this mystery is a completely new approach using a different observing technique instead of simply a further manipulation of the frequency-switched data.

astro-ph.GA↗
arXiv2011

Doppler Boosting May Have Played No Significant Role in the Finding Surveys of Radio-Loud Quasars

There appears to be a fundamental problem facing Active Galactic Nuclei jet models that require highly relativistic ejection speeds and small jet viewing angles to explain the large apparent superluminal motions seen in so many of the radio-loud quasars with high redshift. When the data are looked at closely it is found that only a small percentage of the observed radio frequency flux density from these sources can be Doppler boosted. Without a highly directed, Doppler boosted component that dominates the observed flux, radio sources found in low-frequency finding surveys cannot be preferentially selected with small jet viewing angles. The distribution of jet orientations will then follow the sin$i$ curve associated with a random distribution, where only a very few sources (~1%) will have the small viewing angles (<8 deg) required to explain apparent superluminal motions v{app > 10c, and this makes it difficult to explain how around 33% of the radio-loud AGNs with high redshift can exhibit such highly superluminal motions. When the boosted component is the dominant one it can be argued that in a flux limited sample only those members with small viewing angles would be picked up while those with larger viewing angles (the un-boosted ones) would be missed. However, this is not the case when the boosted component is small and a new model to explain the high apparent superluminal motions may be needed if the redshifts of high-redshift quasars are to remain entirely cosmological.

astro-ph.CO↗
arXiv2011

Evidence that the Bursting Component of the X-ray Radiation From 3C 111 Originates in the PC-Scale Jet

Evidence is presented indicating that the bursting component of the X-ray radiation detected in the nuclear region of the active radio galaxy 3C 111 comes from the blobs ejected in the pc-scale jet and not from the accretion disc. After each new outburst the radio flux density associated with it increases to a peak in ~1 year and then subsides over a period of 1-2 years with the flux falling off exponentially as the blob moves outward and dissipates. Similar peaks (bursts) are seen in the X-ray light curve and a cross-correlation between the two shows a very high correlation with the X-ray peaks leading the radio peaks by ~100 days. A second cross-correlation, this time between the radio event start times and the X-ray light curve, also shows a significant correlation. When this is taken together with the long (~1 yr) delay between the start of each ejection event and its associated X-ray peak it indicates that this bursting component of the X-ray flux must be associated with the ejected blobs in the pc-scale jet and not with the accretion disc. Because X-ray telescopes do not have the resolution required to resolve the accretion disc area from the pc-scale jet, this paper is the first to present observational evidence that can pinpoint the point of origin of at least those long-timescale X-ray bursts with durations of 1-3 yrs.

astro-ph.CO↗
arXiv2011

New Clues to the Impact Broadening Mystery in Radio Recombination Lines

Problems where impact broadened radio recombination lines appeared narrower than predicted first showed up ~40 years ago at frequencies below ~3 GHz. But it was soon found that the observations could be explained by throwing out the uniform density models and replacing them with variable density ones. However, this problem re-appeared recently when a mysterious line narrowing above quantum numbers of (n,Δn) = (202,8) was reported from sensitive observations of Orion and W51 near 6 GHz. Here it is demonstrated that the narrowing is unlikely to be caused by the data processing technique and therefore must be source related. It is further demonstrated that the observed line narrowing can be tied to one of the fundamental properties of radio recombination lines; namely the fact that the spacing of adjacent n-transitions increases with frequency. The line narrowing is observed to begin when the n-transition density, D_{n}, exceeds ~11.6 transitions per GHz. This may imply that it is somehow related either to a previously overlooked effect in the impact broadening process, or to some unknown parallel process, that is tied to the separation between adjacent n-transitions. Based on these results it can be concluded, as has also been concluded in several theoretical investigations, that the observed line narrowing is not tied to a fixed range of either n or Δn.

astro-ph.GA↗
arXiv2009

Selection Effects in the SDSS Quasar Sample: The Filter Gap Footprint

In the Sloan Digital Sky Survey (SDSS) quasars are targeted using colors and anything that can cause the identifying characteristics of the colors to disappear can create problems in the source selection process. Quasar spectra contain strong emission lines that can seriously affect the colors in photometric systems in which the transmission characteristics vary abruptly and significantly with redshift. When a strong line crosses a gap between two filter passbands the color effects induced by the line change abruptly, and there is also a dimming in apparent brightness compared to those redshifts where the strong line is inside a filter passband where the transmission is high. The strong emission lines in quasars, combined with the varying detectability introduced by the transmission pattern of the five filters, will result in a filter-gap footprint being imprinted on the N(z) distribution, with more quasars being missed when a strong line falls in a filter gap. It is shown here that a periodicity of Delta(z)~0.6 is imprinted on the redshift-number distribution by this selection effect. Because this effect cannot be rigorously corrected for, astronomers need to be aware of it in any investigation that uses the SDSS N(z) distribution. Its presence also means that the SDSS quasar data cannot be used either to confirm or to rule out the Delta(z)~0.6 redshift period reported previously in other, unrelated quasar data.

astro-ph.CO↗
arXiv2009

The Point of Origin of the Radio Radiation from the Unresolved Cores of Radio-Loud Quasars

Locating the exact point of origin of the core radiation in active galactic nuclei (AGN) would represent important progress in our understanding of physical processes in the central engine of these objects. However, due to our inability to resolve the region containing both the central compact object and the jet base, this has so far been difficult. Here, using an analysis in which the lack of resolution does not play a significant role, we demonstrate that it may be impossible even in most radio loud sources for more than a small percentage of the core radiation at radio wavelengths to come from the jet base. We find for 3C279 that $\sim85$ percent of the core flux at 15 GHz must come from a separate, reasonably stable, region that is not part of the jet base, and that then likely radiates at least quasi-isotropically and is centered on the black hole. The long-term stability of this component also suggests that it may originate in a region that extends over many Schwarzschild radii.

astro-ph.CO↗
arXiv2008

The Peculiar Shape of the Beta_(app)-z Distribution Seen in Radio Loud AGN Jets Is Explained Simply and Naturally In the Local Quasar Model

Recently, it was argued that the log(z)-m_{v} plot of 106,000 AGN galaxies could be interpreted as an evolutionary path followed by local AGN galaxies as they age. It was suggested that these objects are born as quasars with a high intrinsic redshift component that decreases with time. When the intrinsic component is large it causes them to be pushed above the standard candle line for brightest radio galaxies on a log(z)-m_{v} plot. In the jets of radio loud AGN galaxies, Beta_(app) is the apparent transverse velocity of the ejected material relative to the speed of light. In the cosmological redshift (CR) model the Beta_(app) vs z distribution has a peculiar shape, and there have been several attempts to explain it. In agreement with the model proposed to explain the log(z)-m_{v} plot, it is shown here that the peculiar shape of the Beta_(app)-z distribution in the CR model is exactly what is expected if the sources are local but their large intrinsic redshifts are assumed to be cosmological in the calculation of Beta_(app). This result not only supports our previous interpretation of the log(z)-m_{v} plot, it further implies that if a large component of the redshift is intrinsic a similar effect should be visible when other parameters are plotted vs z. Examining this it is also found that the results are consistent with the local model.

astro-ph↗
arXiv2007

Evidence in Support of the Local Quasar Model from Inner Jet Structure and Angular Motions in Radio Loud AGN

Radio loud jetted sources with and without extended inner jet structure show good agreement with the simple ballistic ejection scenario proposed in the decreasing intrinsic redshift (DIR) model, where, because of projection effects, those that show the most obvious extended structure and large angular motions are assumed to have jets that lie close to the plane of the sky, and those with little or no structure and small angular motions are assumed to have jets that are coming almost directly towards us. This simple model also predicts several other relations seen in the raw data that, in some cases, may be less easily explained if the redshifts are cosmological and relativistic ejection is required. In particular, for radio-loud sources the source number density is found to be high for sources that are not Doppler boosted but low for highly boosted sources. This is opposite to what is expected, suggesting that Doppler boosting may not be involved at all, which would be in agreement with the DIR model. If so, the reality of relativistic beaming in quasar jets, the assumption of which has been the very foundation of the superluminal motion explanation in the cosmological redshift (CR) model, would then be questioned.

astro-ph↗
arXiv2007

Further Evidence that the Redshifts of AGN Galaxies May Contain Intrinsic Components

In the decreasing intrinsic redshift (DIR) model galaxies are assumed to be born as compact objects that have been ejected with large intrinsic redshift components, z_(i), out of the nuclei of mature AGN galaxies. As young AGN (quasars) they are initially several magnitudes sub-luminous to mature galaxies but their luminosity gradually increases over 10^8 yrs, as z_(i) decreases and they evolve into mature AGN (Seyferts and radio galaxies). Evidence presented here that low- and intermediate-redshift AGN are unquestionably sub-luminous to radio galaxies is then strong support for this model and makes it likely that the high-redshift AGN (quasars) are also sub-luminous, having simply been pushed above the radio galaxies on a logz-m_(v) plot by the presence of a large intrinsic component in their redshifts. An increase in luminosity below z = 0.06 is also seen. It is associated in the DIR model with an increase in luminosity as the sources mature but, if real, is difficult to interpret in the cosmological redshift (CR) model since at this low redshift it is unlikely to be associated with a higher star formation rate or an increase in the material used to build galaxies. Whether it might be possible in the CR model to explain these results by selection effects is also examined.

astro-ph↗
arXiv2007

An Abrupt Upper Envelope Cut-off in the Distribution of Angular Motions in Quasar Jets is Compatible in all Respects with a Simple Non-Relativistic Ejection Model

A remarkable correlation is found in radio-loud quasars and BLLacs when the directly observed angular motions, u, of features ejected in the innermost regions of their jets are plotted on logarithmic scales versus the directly observed 15 GHz flux density, S, of their central engines: an abrupt upper envelope cut-off with a slope of 0.5 is obtained. This upper envelope and slope can be explained in a simple non-relativistic ejection model if (a), radio-loud quasars are radio standard candles and (b), for the sources defining the cut-off, the features are all ejected with similar speeds. The upper envelope is then due to the maximum projected velocity seen when the accretion disk is edge-on, and ejections are in the plane of the sky. In our simple ejection model, where S is a good measure of relative distance, the observed distribution of angular motions can be explained if the radio luminosity of the source is a function of viewing angle, increasing towards face-on. Here we show that when u is plotted versus redshift, z, the same upper envelope cut-off is seen. It is not as sharply defined, since, in this simple model, the u upper envelope will be smeared out by sources lying at different cosmological distances, z_(c). Normalizing all sources to the same distance (1 Jy) using the flux density, S, removes this smearing and improves the sharpness of the upper envelope, supporting our assumption that S is a measure of relative distance. In this model the redshift of quasars cannot be a reliable indication of their distance. (abridged)

astro-ph↗
arXiv2006

Six Peaks Visible in the Redshift Distribution of 46,400 SDSS Quasars Agree with the Preferred Redshifts Predicted by the Decreasing Intrinsic Redshift Model

The redshift distribution of all 46,400 quasars in the Sloan Digital Sky Survey (SDSS) Quasar Catalog III, Third Data Release, is examined. Six Peaks that fall within the redshift window below z = 4, are visible. Their positions agree with the preferred redshift values predicted by the decreasing intrinsic redshift (DIR) model, even though this model was derived using completely independent evidence. A power spectrum analysis of the full dataset confirms the presence of a single, significant power peak at the expected redshift period. Power peaks with the predicted period are also obtained when the upper and lower halves of the redshift distribution are examined separately. The periodicity detected is in linear z, as opposed to log(1+z). Because the peaks in the SDSS quasar redshift distribution agree well with the preferred redshifts predicted by the intrinsic redshift relation, we conclude that this relation, and the peaks in the redshift distribution, likely both have the same origin, and this may be intrinsic redshifts, or a common selection effect. However, because of the way the intrinsic redshift relation was determined it seems unlikely that one selection effect could have been responsible for both.

astro-ph↗
arXiv2006

Evidence that Quasars and Related Active Galaxies are Good Radio Standard Candles and that they are Likely to be a Lot Closer than their Redshifts Imply

For many years some astronomers have continued to argue, using redshift periodicities and quasar-galaxy associations, that quasars may be closer than their redshifts imply. Here, for the first time using raw radio data, I re-examine this question and find new evidence that supports this argument. Using VLBA flux densities and angular motions in jets, I show that the central engine of quasars and BL Lac objects appears to be a good radio standard candle. Using this information, relative distances are calculated and absolute radio distances are then obtained by referencing to a source whose true distance has been obtained using Cepheid variables. The results reveal that in this model most of the strong radio sources found in early surveys are nearer than 100 Mpc. (abridged)

astro-ph↗
arXiv2004

Distances of Quasars and Quasar-Like Galaxies: Further Evidence that QSOs may be Ejected from Active Galaxies

If high-redshift QSOs are ejected from the nuclei of low-redshift galaxies, as some have claimed, a large portion of their redshift must be intrinsic (non-Doppler). If these intrinsic components have preferred values, redshifts will tend to cluster around these preferred values and produce peaks in the redshift distribution. Doppler ejection and Hubble flow components will broaden each peak. Because ejection velocities are randomly directed and Hubble flow components are always positive, in this model all peaks are expected to show an asymmetry, extending further out in the red wing. If peaks are present showing this predicted asymmetry, it can lead directly to an estimate of quasar distances. Using two quasar samples, one with high redshifts and one with low, it is shown here that not only do all peaks in these two redshift distributions occur at previously predicted preferred values, they also all show the predicted extra extension in the red wing. For the low and high redshift samples the mean cosmological components are found to be z$_{c} \sim 0.024$ and $\sim 0.066$, respectively. The difference can be explained by the improved detection limit of the high redshift sample. These results offer further evidence in favor of the model proposing that QSOs are ejected from active galaxies.

astro-ph↗
arXiv2004

Discrete Components in the Radial Velocities of ScI Galaxies

We examine the V_{CMB} velocities and Tully-Fisher distances of 83 ScI galaxies and find that their velocities contain the same discrete velocity components identified previously by Tifft. After removing the discrete velocity components, the scatter remaining on the Hubble plot is in good agreement with the Tully-Fisher distance uncertainties. Although there is, as yet, no physical explanation for these discrete components, the fact that they appear to be identical to those found previously by Tifft suggests that their reality needs to be taken seriously.

astro-ph↗
arXiv2003

Discrete Components in the Radial Velocities of 83 ScI Galaxies: Examining the Accuracy of Tully-Fisher Distances

Our previous analyses of the redshifts and distances of galaxies included 55 spiral galaxies and 36 Type Ia Supernovae galaxies in three separate groups. All groups showed evidence that their radial velocities contain the same discrete velocity components that are predicted from the early work of Tifft. Here we examine another new source sample containing 83 ScI galaxies. When B-band distances are used, we find clear evidence that the discrete velocities defined by Tifft's most common velocity period are present in the radial velocities of these galaxies. Assuming this is true, we are then able to use the visibility, or ease of detection, of the discrete components as an indication of the distance accuracy of the galaxies, comparing B- and I-band distances, galaxy inclination ranges, and galaxy rotation velocity ranges. We find (a), that, contrary to expectation, B-band distances for these sources are considerably more accurate than I-band, (b), that the distance accuracy varies with galaxy inclination, as expected, with the most consistent distances obtained for inclinations between 48 and 65 degrees, and (c), that distances are probably more accurate for small rotation velocities. With these results for the 83 ScI galaxies, discrete velocity components have now been detected in all 174 galaxies examined.

astro-ph↗