129 research outputs found
Spectroscopy along Multiple, Lensed Sightlines through Outflowing Winds in the Quasar SDSS J1029+2623
We study the origin of absorption features on the blue side of the C IV broad
emission line of the large-separation lensed quasar SDSS J1029+2623 at z_em ~
2.197. The quasar images, produced by a foreground cluster of galaxies, have a
maximum separation angle of ~ 22".5. The large angular separation suggests that
the sight-lines to the quasar central source can go through different regions
of outflowing winds from the accretion disk of the quasar, providing a unique
opportunity to study the structure of outflows from the accretion disk, a key
ingredient for the evolution of quasars as well as for galaxy formation and
evolution. Based on medium- and high-resolution spectroscopy of the two
brightest images conducted at the Subaru telescope, we find that each image has
different intrinsic levels of absorptions, which can be attributed either to
variability of absorption features over the time delay between the lensed
images, ~ 774 days, or to the fine structure of quasar outflows probed by the
multiple sight-lines toward the quasar. While both these scenarios are
consistent with the current data, we argue that they can be distinguished with
additional spectroscopic monitoring observations.Comment: 17 pages, including 7 figures; accepted for publication in the
Astronomical Journa
Adaptive optics observations of the gravitationally lensed quasar SDSS J1405+0959
We present the result of Subaru Telescope multi-band adaptive optics
observations of the complex gravitationally lensed quasar SDSS J1405+0959,
which is produced by two lensing galaxies. These observations reveal
dramatically enhanced morphological detail, leading to the discovery of an
additional object 0. 26'' from the secondary lensing galaxy, as well as three
collinear clumps located in between the two lensing galaxies. The new object is
likely to be the third quasar image, although the possibility that it is a
galaxy cannot be entirely excluded. If confirmed via future observations, it
would be the first three image lensed quasar produced by two galaxy lenses. In
either case, we show based on gravitational lensing models and photometric
redshift that the collinear clumps represent merging images of a portion of the
quasar host galaxy, with a magnification factor of 15 - 20, depending on the
model.Comment: 12 pages, 8 figures, 7 tables. Submitted to MNRA
Spectroscopic Observations of the Outflowing Wind in the Lensed Quasar SDSS J1001+5027
We performed spectroscopic observations of the small-separation lensed quasar
SDSS J1001+5027, whose images have an angular separation , and placed constraints on the physical properties of
gas clouds in the vicinity of the quasar (i.e., in the outflowing wind launched
from the accretion disk). The two cylinders of sight to the two lensed images
go through the same region of the outflowing wind and they become fully
separated with no overlap at a very large distance from the source (
pc). We discovered a clear difference in the profile of the CIV broad
absorption line (BAL) detected in the two lensed images in two observing
epochs. Because the kinematic components in the BAL profile do not vary in
concert, the observed variations cannot be reproduced by a simple change of
ionization state. If the variability is due to gas motion around the background
source (i.e., the continuum source), the corresponding rotational velocity is
km/s, and their distance from the source is
pc assuming Keplerian motion. Among three MgII and three CIV NAL systems that
we detected in the spectra, only the MgII system at shows a
hint of variability in its MgI profile on a rest-frame time scale of days and an obvious velocity shear between the sightlines
whose physical separation is kpc. We interpret this as the result of
motion of a cosmologically intervening absorber, perhaps located in a
foreground galaxy.Comment: 15 pages, including 7 figures; accepted for publication in the
Astrophysical Journa
Discovery of Multiply Imaged Galaxies behind the Cluster and Lensed Quasar SDSS J1004+4112
We have identified three multiply imaged galaxies in Hubble Space Telescope
images of the redshift z=0.68 cluster responsible for the large-separation
quadruply lensed quasar, SDSS J1004+4112. Spectroscopic redshifts have been
secured for two of these systems using the Keck I 10m telescope. The most
distant lensed galaxy, at z=3.332, forms at least four images, and an Einstein
ring encompassing 3.1 times more area than the Einstein ring of the lensed QSO
images at z=1.74, due to the greater source distance. For a second multiply
imaged galaxy, we identify Ly_alpha emission at a redshift of z=2.74. The
cluster mass profile can be constrained from near the center of the brightest
cluster galaxy, where we observe both a radial arc and the fifth image of the
lensed quasar, to the Einstein radius of the highest redshift galaxy, ~110 kpc.
Our preliminary modeling indicates that the mass approximates an elliptical
body, with an average projected logarithmic gradient of ~-0.5. The system is
potentially useful for a direct measurement of world models in a previously
untested redshift range.Comment: 5 pages, 3 figures. Accepted by ApJL. High resolution version of the
paper can be found at: http://wise-obs.tau.ac.il/~kerens/papers.htm
Implications of the mild gas motion found with Hitomi in the core of the Perseus cluster
Based mainly on X-ray observations, studies are made on interactions between
the intra-cluster medium (ICM) in clusters of galaxies and their member
galaxies. Through (magneto)hydrodynamic and gravitational channels, the moving
galaxies are expected to drag the ICM around them, and transfer to the ICM some
fraction of their dynamical energies on cosmological time scales. This
hypothesis is in line with several observations, including the possible
cosmological infall of galaxies towards the cluster center, found over
redshifts of z~1 to z~0. Further assuming that the energy lost by the galaxies
is first converted into ICM turbulence and then dissipated, this picture can
explain the subsonic and uniform ICM turbulence, measured with Hitomi in the
core region of the Perseus cluster. The scenario may also explain several other
unanswered problems regarding clusters of galaxies, including what prevents the
ICM from the expected radiative cooling, how the various mass components in
nearby clusters have attained different radial distributions, and how a thermal
stability is realized between hot and cool ICM components that co-exist around
cD galaxies. This view is also considered to pertain to the general scenario of
galaxy evolution, including their environmental effects.Comment: 15 pages, 3 figures, accepted for publication in A&
Galaxy Infall by Interacting with its Environment: a Comprehensive Study of 340 Galaxy Clusters
To study systematically the evolution on the angular extents of the galaxy,
ICM, and dark matter components in galaxy clusters, we compiled the optical and
X-ray properties of a sample of 340 clusters with redshifts , based on
all the available data with the Sloan Digital Sky Survey (SDSS) and {\it
Chandra}/{\it XMM-Newton}. For each cluster, the member galaxies were
determined primarily with photometric redshift measurements. The radial ICM
mass distribution, as well as the total gravitational mass distribution, were
derived from a spatially-resolved spectral analysis of the X-ray data. When
normalizing the radial profile of galaxy number to that of the ICM mass, the
relative curve was found to depend significantly on the cluster redshift; it
drops more steeply towards outside in lower redshift subsamples. The same
evolution is found in the galaxy-to-total mass profile, while the ICM-to-total
mass profile varies in an opposite way. We interpret that the galaxies, the
ICM, and the dark matter components had similar angular distributions when a
cluster was formed, while the galaxies travelling interior of the cluster have
continuously fallen towards the center relative to the other components, and
the ICM has slightly expanded relative to the dark matter although it suffers
strong radiative loss. This cosmological galaxy infall, accompanied by an ICM
expansion, can be explained by considering that the galaxies interact strongly
with the ICM while they are moving through it. The interaction is considered to
create a large energy flow of erg per cluster from
the member galaxies to their environment, which is expected to continue over
cosmological time scales.Comment: 55 pages, 22 figures, accepted for publication in Astrophysical
Journa
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