1,506 research outputs found
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
The Rewards of Patience: An 822 Day Time Delay in the Gravitational Lens SDSS J1004+4112
We present 107 new epochs of optical monitoring data for the four brightest
images of the gravitational lens SDSS J1004+4112 observed between October 2006
and June 2007. Combining this data with the previously obtained light curves,
we determine the time delays between images A, B and C. We confirm our previous
measurement finding that A leads B by dt_BA=40.6+-1.8 days, and find that image
C leads image A by dt_CA=821.6+-2.1 days. The lower limit on the remaining
delay is that image D lags image A by dt_AD>1250 days. Based on the
microlensing of images A and B we estimate that the accretion disk size at a
rest wavelength of 2300 angstrom is 10^{14.8+-0.3} cm for a disk inclination of
cos{i}=1/2, which is consistent with the microlensing disk size-black hole mass
correlation function given our estimate of the black hole mass from the MgII
line width of logM_BH/M_sun=8.44+-0.14. The long delays allow us to fill in the
seasonal gaps and assemble a continuous, densely sampled light curve spanning
5.7 years whose variability implies a structure function with a logarithmic
slope of gamma = 0.35+-0.02. As C is the leading image, sharp features in the C
light curve can be intensively studied 2.3 years later in the A/B pair,
potentially allowing detailed reverberation mapping studies of a quasar at
minimal cost.Comment: Submitted to ApJ, 12 pages, 3 figure
Difference Imaging of Lensed Quasar Candidates in the SDSS Supernova Survey Region
Difference imaging provides a new way to discover gravitationally lensed
quasars because few non-lensed sources will show spatially extended, time
variable flux. We test the method on lens candidates in the Sloan Digital Sky
Survey (SDSS) Supernova Survey region from the SDSS Quasar Lens Search (SQLS)
and their surrounding fields. Starting from 20768 sources, including 49 SDSS
quasars and 36 candidate lenses/lensed images, we find that 21 sources
including 15 SDSS QSOs and 7 candidate lenses/lensed images are non-periodic
variable sources. We can measure the spatial structure of the variable flux for
18 of these sources and identify only one as a non-point source. This source
does not display the compelling spatial structure of the variable flux of known
lensed quasars, so we reject it as a lens candidate. None of the lens
candidates from the SQLS survive our cuts. Given our effective survey area of
order 0.71 square degrees, this indicates a false positive rate of order one
per square degree for themethod. The fraction of quasars not found to be
variable and the false positive rate should both fall if we analyze the full,
later data releases for the SDSS fields. While application of the method to the
SDSS is limited by the resolution, depth, and sampling of the survey, several
future surveys such as Pan-STARRS, LSST, and SNAP will avoid these limitations.Comment: Submitted to ApJ, 24 pages, 5 figure
Superfluid properties of one-component Fermi gas with an anisotropic p-wave interaction
We investigate superfluid properties and strong-coupling effects in a
one-component Fermi gas with an anisotropic p-wave interaction. Within the
framework of the Gaussian fluctuation theory, we determine the superfluid
transition temperature , as well as the temperature at which
the phase transition from the -wave pairing state to the -wave
state occurs below . We also show that while the anisotropy of the
p-wave interaction enhances in the strong-coupling regime, it
suppresses .Comment: 7 pages, 3 figures, proceedings of QFS 201
Fermi surface of the filled-skutterudite superconductor LaRu4P12: A clue to the origin of the metal-insulator transition in PrRu4P12
We report the de Haas-van Alphen (dHvA) effect and magnetoresistance in the
filled-skutterudite superconductor LaRu4P12, which is a reference material of
PrRu4P12 that exhibits a metal-insulator (M-I) transition at T_MI~60 K. The
observed dHvA branches for the main Fermi surface (FS) are well explained by
the band-structure calculation, using the full potential linearized
augmented-plane-wave method with the local-density approximation, suggesting a
nesting instability with q =(1,0,0) in the main multiply connected FS as
expected also in PrRu4P12. Observed cyclotron effective masses of
(2.6-11.8)m_0, which are roughly twice the calculated masses, indicate the
large mass enhancement even in the La-skutterudites. Comparing the FS between
LaRu4P12 and PrRu4P12, an essential role of c-f hybridization cooperating with
the FS nesting in driving the the M-I transition in PrRu4P12 has been
clarified.Comment: Appeared in Physical Review
Discovery of Four Gravitationally Lensed Quasars from the Sloan Digital Sky Survey
We present the discovery of four gravitationally lensed quasars selected from
the spectroscopic quasar catalog of the Sloan Digital Sky Survey. We describe
imaging and spectroscopic follow-up observations that support the lensing
interpretation of the following four quasars: SDSS J0832+0404 (image separation
\theta=1.98", source redshift z_s=1.115, lens redshift z_l=0.659); SDSS
J1216+3529 (\theta=1.49", z_s=2.012); SDSS J1322+1052 (\theta=2.00",
z_s=1.716); and SDSS J1524+4409 (\theta=1.67", z_s=1.210, z_l=0.320). Each
system has two lensed images. We find that the fainter image component of SDSS
J0832+0404 is significantly redder than the brighter component, perhaps because
of differential reddening by the lensing galaxy. The lens potential of SDSS
J1216+3529 might be complicated by the presence of a secondary galaxy near the
main lensing galaxy.Comment: 25 pages, 10 figures, 6 tables, accepted for publication in A
The Sloan Digital Sky Survey Quasar Lens Search. III. Constraints on Dark Energy from the Third Data Release Quasar Lens Catalog
We present cosmological results from the statistics of lensed quasars in the
Sloan Digital Sky Survey (SDSS) Quasar Lens Search. By taking proper account of
the selection function, we compute the expected number of quasars lensed by
early-type galaxies and their image separation distribution assuming a flat
universe, which is then compared with 7 lenses found in the SDSS Data Release 3
to derive constraints on dark energy under strictly controlled criteria. For a
cosmological constant model (w=-1) we obtain
\Omega_\Lambda=0.74^{+0.11}_{-0.15}(stat.)^{+0.13}_{-0.06}(syst.). Allowing w
to be a free parameter we find
\Omega_M=0.26^{+0.07}_{-0.06}(stat.)^{+0.03}_{-0.05}(syst.) and
w=-1.1\pm0.6(stat.)^{+0.3}_{-0.5}(syst.) when combined with the constraint from
the measurement of baryon acoustic oscillations in the SDSS luminous red galaxy
sample. Our results are in good agreement with earlier lensing constraints
obtained using radio lenses, and provide additional confirmation of the
presence of dark energy consistent with a cosmological constant, derived
independently of type Ia supernovae.Comment: 9 pages, 3 figures, 2 tables, accepted for publication in A
MULTI-SIGHTLINE OBSERVATION OF NARROW ABSORPTION LINES IN LENSED QUASAR SDSS J1029+2623
We exploit the widely separated images of the lensed quasar SDSS J1029+2623 (z(em) = 2.197, theta = 22.'' 5) to observe its outflowing wind through two different sightlines. We present an analysis of three observations, including two with the Subaru telescope in 2010 February and 2014 April, separated by four years, and one with the Very Large Telescope, separated from the second Subaru observation by similar to 2 months. We detect 66 narrow absorption lines (NALs), of which 24 are classified as intrinsic NALs that are physically associated with the quasar based on partial coverage analysis. The velocities of intrinsic NALs appear to cluster around values of v(ej) similar to 59,000, 43,000, and 29,000 km s(-1), which is reminiscent of filamentary structures obtained by numerical simulations. There are no common intrinsic NALs at the same redshift along the two sightlines, implying that the transverse size of the NAL absorbers should be smaller than the sightline distance between two lensed images. In addition to the NALs with large ejection velocities of v(ej) > 1000 km s(-1), we also detect broader proximity absorption lines (PALs) at za(bs) similar to z(em). The PALs are likely to arise in outflowing gas at a distance of r = 8.7 x 10(3) cm(-3). These limits are based on the assumption that the variability of the lines is due to recombination. We discuss the implications of these results on the three-dimensional structure of the outflow.ArticleASTROPHYSICAL JOURNAL.825(1):25(2016)journal articl
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