1,990 research outputs found
X-ray Bright QSO's around NGC 3079
NGC 3079 is a very active, disturbed galaxy which has been observed to have
X-ray and radio ejections from it as well as an optical superbubble along its
minor axis. Here we show that the brightest X-ray sources within about 40
arcmin are in large excess of background values. The X-ray sources are
identified as quasars and AGN's which are aligned and spaced across the Seyfert
nucleus to a degree which is unlikely to be due to chance. The famous double
quasar which has been interpreted as a gravitational lens is discussed in terms
of the the X - ray and ULX sources which appear associated with NGC 3079.Comment: 6 figures, submitted to Ap
First tentative detection of anisotropy in the QSO distribution around nearby edge-on spiral galaxies
AIMS. To check whether the polar angle distribution of QSOs around nearby
spiral galaxies is isotropic or not.
METHODS. A statistical analysis of the polar angle distribution of large
samples of QSOs from the SDSS survey and Monte Carlo simulations to calculate
their significance are carried out.
RESULTS. There is a clear excess of QSOs near the minor axis with respect to
the major axis of nearby edge-on spiral galaxies, significant at a level
3.5-sigma up to angular distances of 3 deg. (or ~1.7 Mpc) from the centre of
each galaxy. The significance is increased to 3.9-sigma with the z>0.5 QSOs,
and it reaches 4.8-sigma if we include galaxies whose circles of radius 3
degrees are covered by the SDSS in more than 98% (instead of 100%) of the area.
CONCLUSIONS. Gravitational lensing in the halo of nearby galaxies or
extinction seem insufficient to explain the observed anisotropic distribution
of QSOs. The anisotropic distribution agrees qualitatively with the predictions
of Arp's models, which claim that QSOs are ejected by galaxies along the
rotation axis, although Arp's prediction give a distance of the QSOs ~3 times
smaller than that found here. In any case, a chance fluctuation, although
highly improbable, might be a possibility rather than a true anisotropy, and
the present results should be corroborated by other groups and samples, so we
prefer to consider it as just a first tentative detection.Comment: 16 pages, accepted to be published in A&
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.Comment: 12 pages, 2 figures. Contains response to referees suggestions.
(Accepted for ApJL
Evidence for Intrinsic Redshifts in Normal Spiral Galaxies
The Tully-Fisher Relationship (TFR) is utilized to identify anomalous
redshifts in normal spiral galaxies. Three redshift anomalies are identified in
this analysis: (1) Several clusters of galaxies are examined in which late type
spirals have significant excess redshifts relative to early type spirals in the
same clusters, (2) Galaxies of morphology similar to ScI galaxies are found to
have a systematic excess redshift relative to the redshifts expected if the
Hubble Constant is 72 km s-1 Mpc-1, (3) individual galaxies, pairs, and groups
are identified which strongly deviate from the predictions of a smooth Hubble
flow. These redshift deviations are significantly larger than can be explained
by peculiar motions and TFR errors. It is concluded that the redshift anomalies
identified in this analysis are consistent with previous claims for large
non-cosmological (intrinsic) redshifts.Comment: Accepted for publication at Astrophysics&Space Science. 36 pages
including 8 tables and 7 figure
NGC 3628: Ejection Activity Associated with Quasars
NGC3628 is a well-studied starburst/low level AGN galaxy in the Leo Triplet
noted for its extensive outgassed plumes of neutral hydrogen. QSOs are shown to
be concentrated around NGC3628 and aligned with the HI plumes. The closest high
redshift quasar has z=2.15 and is at the tip of an X-ray filament emerging
along the minor axis HI plume. Location at this point has an accidental
probability of ~2x10^-4. In addition a coincident chain of optical objects
coming out along the minor axis ends on this quasar. More recent measures on a
pair of strong X-ray sources situated at 3.2 and 5.4 arcmin on either side of
NGC3628 along its minor axis, reveal that they have nearly identical redshifts
of z=0.995 and 0.981. The closer quasar lies directly in the same X-ray
filament which extends from the nucleus out 4.1 arcmin to end on the quasar of
z=2.15. The chain of objects SW along the minor axis of NGC3628 has been imaged
in four colors with the VLT. Images and spectra of individual objects within
the filament are reported. It is suggested that material in various physical
states and differing intrinsic redshifts is ejected out along the minor axis of
this active, disturbed galaxy.Comment: 8 pages, 5 figures. Accepted for publication in A&A. Postscript file
including full resolution figures at
http://www.eso.org/~fpatat/ngc3628/paper_ngc3628.ps.g
Toward a Clean Sample of Ultra-Luminous X-ray Sources
CONTEXT. Observational follow-up programmes for the characterization of
ultra-luminous X-ray sources (ULXs) require the construction of clean samples
of such sources in which the contamination by foreground/background sources is
minimum.
AIMS. In this article we calculate the degree of foreground/background
contaminants among the ULX sample candidates in the Colbert & Ptak (2002)
catalogue and compare these computations with available spectroscopical
identifications.
METHODS. We use statistics based on known densities of X-ray sources and
AGN/QSOs selected in the optical. The analysis is done individually for each
parent galaxy. The existing identifications of the optical counterparts are
compiled from the literature.
RESULTS. More than a half of the ULXs, within twice the distance of the major
axis of the 25 mag/arcsec isophote from RC3 nearby galaxies and with X-ray
luminosities [2-10 keV] erg/s, are expected to be high
redshift background QSOs. A list of 25 objects (clean sample) confirmed to be
real ULXs or to have a low probability of being contaminant
foreground/background objects is provided.Comment: 9 pages, accepted in A&
The nature of the ultraluminous X-ray sources inside galaxies and their relation to local QSOs
It is suggested that many of the ultraluminous compact x-ray sources now
being found in the main bodies of galaxies, particularly those that are active,
like M82, NGC 3628 and others, are "local" QSOs, or BL Lac objects, with high
intrinsic redshifts in the process of being ejected from those galaxies.
Evidence in support of this hypothesis is summarized.Comment: submitted to A&A Letter
The Discovery of a High Redshift X-ray Emitting QSO Very Close to the Nucleus of NGC 7319
A strong X-ray source only 8" from the nucleus of the Sy2 galaxy NGC 7319 in
Stephan's Quintet has been discovered by Chandra. We have identified the
optical counterpart and show it is a QSO with . It is also a ULX
with . From the optical spectra of the QSO
and interstellar gas in the galaxy (z = .022) we show that it is very likely
that the QSO and the gas are interacting.Comment: 8 figures, 5 color, minimized ps siz
Natural Regulation of Energy Flow in a Green Quantum Photocell
Manipulating the flow of energy in nanoscale and molecular photonic devices
is of both fundamental interest and central importance for applications in
light harvesting optoelectronics. Under erratic solar irradiance conditions,
unregulated power fluctuations in a light harvesting photocell lead to
inefficient energy storage in conventional solar cells and potentially fatal
oxidative damage in photosynthesis. Here, we show that regulation against these
fluctuations arises naturally within a two-channel quantum heat engine
photocell, thus enabling the efficient conversion of varying incident solar
spectrum at Earth's surface. Remarkably, absorption in the green portion of the
spectrum is avoided, as it provides no inherent regulatory benefit. Our
findings illuminate a quantum structural origin of regulation, provide a novel
optoelectronic design strategy, and may elucidate the link between
photoprotection in photosynthesis and the predominance of green plants on
Earth.Comment: 17 pages, 4 figure
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