266 research outputs found
SIZE-CONTROLLED PREPARATION OF GOLD NANOPARTICLES BY USING GUANOSINE MONOPHOSPHATE
This study was financially supported by the Russian Foundation for Basic Research (project No 20-33-90296\20)
Bound state vector solitons with locked and precessing states of polarization
We report experimental observation of new tightly and loosely bound state vector solitons with locked and precessing states of polarization in a carbon nanotube mode locked fiber laser in the anomalous dispersion regime
Slow deterministic vector rogue waves
For an erbium-doped fiber laser mode-locked by carbon nanotubes, we demonstrate experimentally and theoretically a new type of the vector rogue waves emerging as a result of the chaotic evolution of the trajectories between two orthogonal states of polarization on the Poincare sphere. In terms of fluctuation induced phenomena, by tuning polarization controller for the pump wave and in-cavity polarization controller, we are able to control the Kramers time, i.e. the residence time of the trajectory in vicinity of each orthogonal state of polarization, and so can cause the rare events satisfying rogue wave criteria and having the form of transitions from the state with the long residence time to the state with a short residence time
KiDS-SQuaD: The KiDS Strongly lensed Quasar Detection project
New methods have been recently developed to search for strong gravitational
lenses, in particular lensed quasars, in wide-field imaging surveys. Here, we
compare the performance of three different, morphology- and photometry- based
methods to find lens candidates over the Kilo-Degree Survey (KiDS) DR3
footprint (440 deg). The three methods are: i) a multiplet detection in
KiDS-DR3 and/or Gaia-DR1, ii) direct modeling of KiDS cutouts and iii)
positional offsets between different surveys (KiDS-vs-Gaia, Gaia-vs-2MASS),
with purpose-built astrometric recalibrations. The first benchmark for the
methods has been set by the recovery of known lenses. We are able to recover
seven out of ten known lenses and pairs of quasars observed in the KiDS DR3
footprint, or eight out of ten with improved selection criteria and looser
colour pre-selection. This success rate reflects the combination of all methods
together, which, taken individually, performed significantly worse (four lenses
each). One movelty of our analysis is that the comparison of the performances
of the different methods has revealed the pros and cons of the approaches and,
most of all, the complementarities. We finally provide a list of high-grade
candidates found by one or more methods, awaiting spectroscopic follow-up for
confirmation. Of these, KiDS 1042+0023 is to our knowledge the first confirmed
lensed quasar from KiDS, exhibiting two quasar spectra at the same source
redshift at either sides of a red galaxy, with uniform flux-ratio
over the wavelength range
Comment: 12 pages, 4 figures, 4 tables, accepted for publication in MNRA
Mulitiscale spatiotemporal structures in mode-locked fiber lasers
Using an Er-doped fiber laser as a test bed, here we for the first time experimentally demonstrate the simultaneous effect of the fast scale (round-trip time) and slow scale (thousands round-trip time) instabilities on the emergence of breathers similar to the Akhmediev breathers, Peregrine solitons, and partially mode-locked chaotic solitons. The anomalous statistics of the laser output power justifies the connection of the observed spatiotemporal structures with bright and dark rogue waves. Apart from the interest in laser physics for revealing mechanisms of the multiscale dynamics, the obtained results can be of fundamental interest for studying spatiotemporal patterns induced by the interplay of the mechanisms mentioned above in various distributed systems
Time delays in PG1115+080: new estimates
We report new estimates of the time delays in the quadruple gravitationally
lensed quasar PG1115+080, obtained from the monitoring data in filter R with
the 1.5-m telescope at the Maidanak Mountain (Uzbekistan, Central Asia) in
2004-2006. The time delays are 16.4 days between images C and B, and 12 days
between C and A1+A2, with image C being leading for both pairs. The only known
estimates of the time delays in PG1115 are those based on observations by
Schechter et al. (1997) -- 23.7 and 9.4 days between images C and B, C and
A1+A2, respectively, as calculated by Schechter et al., and 25 and 13.3 days as
revised by Barkana (1997) for the same image components with the use of another
method. The new values of time delays in PG 1115+080 may be expected to provide
larger estimates of the Hubble constant thus decreasing a diversity between the
H_0 estimates taken from gravitationally lensed quasars and with other methods.Comment: 5 pages, 2 figures, Accepted for publication in MNRAS Letter
Researches of air and fuel rate influence on oxygen level in emissions of new type medium power coal boiler
The article deals with sustained fire coal boilers requirements engineering from a creating energy saving and ecological compatibility point of view. The article gives experimental data obtained on boilers which was made by LLP "Карплаз", Karaganda, Republic of Kazakhstan
Spectroscopic confirmation and modelling of two lensed quadruple quasars in the Dark Energy Survey public footprint
Quadruply lensed quasars are extremely rare objects, but incredibly powerful cosmological tools. Only few dozen are known in the whole sky. Here we present the spectroscopic confirmation of two new quadruplets WG0214-2105 and WG2100-4452 discovered by Agnello & Spiniello (2018) within the Dark Energy Survey public footprints. We have conducted spectroscopic follow-up of these systems with the Southern African Large Telescope as part of a program that aims at confirming the largest possible number of strong gravitational lenses in the equatorial and southern hemisphere. For both systems, we present the sources spectra that allowed us to estimate their redshifts and unambiguously confirm their lensing nature. For the brighter deflector (WG2100-4452) we measure the spectroscopic redshift and the stellar velocity dispersion from optical absorption lines in the spectrum. For the other system we infer the lens redshift from photometry, being the quality of the spectra not good enough. We obtain photometry for both lenses, directly from multi-band images, isolating the lenses from the quasars. One of the quadruplets, WG0214-2105, was also observed by Pan-STARRS, allowing us to estimate the apparent brightness of each quasar image at two different epochs, and thus to find evidence for flux variability. This result could suggest a microlensing event for the faintest components, although intrinsic variability cannot be excluded with only two epochs. Finally, we present simple lens models for both quadruplets, obtaining Einstein radii, SIE velocity dispersions, ellipticities, and position angles of the lenses, as well as time delay predictions assuming a concordance cosmological model
PG 1115+080: variations of the A2/A1 flux ratio and new values of the time delays
We report the results of our multicolor observations of PG 1115+080 with the
1.5-m telescope of the Maidanak Observatory (Uzbekistan, Central Asia) in
2001-2006. Monitoring data in filter R spanning the 2004, 2005 and 2006 seasons
(76 data points) demonstrate distinct brightness variations of the source
quasar with the total amplitude of almost 0.4 mag. Our R light curves have
shown image C leading B by 16.4d and image (A1+A2) by 12d that is inconsistent
with the previous estimates obtained by Schechter et al. in 1997 - 24.7d
between B and C and 9.4d between (A1+A2) and C. The new values of time delays
in PG 1115+080 must result in larger values for the Hubble constant, thus
reducing difference between its estimates taken from the gravitational lenses
and with other methods. Also, we analyzed variability of the A2/A1 flux ratio,
as well as color changes in the archetypal "fold" lens PG 1115+080. We found
the A1/A2 flux ratio to grow during 2001-2006 and to be larger at longer
wavelengths. In particular, the A2/A1 flux ratio reached 0.85 in filter I in
2006. We also present evidence that both the A1 and A2 images might have
undergone microlensing during 2001-2006, with the descending phase for A1 and
initial phase for A2. We find that the A2/A1 flux ratio anomaly in PG 1115 can
be well explained both by microlensing and by finite distance of the source
quasar from the caustic fold.Comment: 14 pages, 7 figures, 8 tables, Accepted for publication in MNRA
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