7,920 research outputs found
Generation of photon pairs using polarization-dependent two-photon absorption
We propose a new method for generating photon pairs from coherent light using
polarization-dependent two-photon absorption. We study the photon statistics of
two orthogonally polarized modes by solving a master equation, and show that
when we prepare a coherent state in one polarization mode, photon pairs are
created in the other mode. The photon pairs have the same frequency as that of
the incident light.Comment: 4 pages, 3 figures, submitted to PR
Global dispersive solutions for the Gross-Pitaevskii equation in two and three dimensions
We study asymptotic behaviour at time infinity of solutions close to the
non-zero constant equilibrium for the Gross-Pitaevskii equation in two and
three spatial dimensions. We construct a class of global solutions with
prescribed dispersive asymptotic behavior, which is given in terms of the
linearized evolution
CO(J=6-5) Observations of the Quasar SDSS1044-0125 at z = 5.8
We present a result of the quasar CO(J=6-5) observations of SDSSp
J104433.04-012502.2 at z = 5.8. Ten-days observations with the Nobeyama
Millimeter Array yielded an rms noise level of ~ 2.1 mJy/beam in a frequency
range from 101.28 GHz to 101.99 GHz at a velocity resolution of 120 km/s. No
significant clear emission line was detected in the observed field and
frequency range. Three sigma upper limit on the CO(J=6-5) luminosity of the
object is 2.8 x 10^10 K km/s pc^2, corresponding to a molecular gas mass of 1.2
x 10^11 Solar Mass, if a conversion factor of 4.5 Solar Mass /(K km/s pc^2) is
adopted. The obtained upper limit on CO luminosity is slightly smaller than
those observed in quasars at z=4-5 toward which CO emissions are detected.Comment: 4 pages, 3 figures, LaTeX2e, to appear in Publication of Astronomical
Society of Japan (PASJ), Postscript file available at
ftp://ftp.kusastro.kyoto-u.ac.jp/pub/iwata/preprint/sdss1044/sdss.ps.g
Dense and Warm Molecular Gas between Double Nuclei of the Luminous Infrared Galaxy NGC 6240
High spatial resolution observations of the 12CO(1-0), HCN(1-0), HCO+(1-0),
and 13CO(1-0) molecular lines toward the luminous infrared merger NGC 6240 have
been performed using the Nobeyama Millimeter Array and the RAINBOW
Interferometer. All of the observed molecular emission lines are concentrated
in the region between the double nuclei of the galaxy. However, the
distributions of both HCN and HCO+ emissions are more compact compared with
that of 12CO, and they are not coincident with the star-forming regions. The
HCN/12CO line intensity ratio is 0.25; this suggests that most of the molecular
gas between the double nuclei is dense. A comparison of the observed high
HCN/13CO intensity ratio, 5.9, with large velocity gradient calculations
suggests that the molecular gas is dense [n(H_2)=10^{4-6} cm^-3] and warm
(T_kin>50 K). The observed structure in NGC 6240 may be explained by time
evolution of the molecular gas and star formation, which was induced by an
almost head-on collision or very close encounter of the two galactic nuclei
accompanied with the dense gas and star-forming regions.Comment: 25 pages, 8 figures, To be appeared in PASJ 57, No.4 (August 25,
2005) issu
Detection of laser-UV microirradiation-induced DNA photolesions by immunofluorescent staining
A low-power laser-UV microbeam of wave-length 257 nm was used for microirradiation of a small part of the nucleus of Chinese hamster cells. Following fixation in interphase or in the subsequent metaphase indirect immunofluorescent staining was performed with antiserum to photoproducts of DNA treated with far UV light.
The results show that antibodies specific for UV-irradiated DNA can be used for a direct detection of laser-UV microirradiation-induced DNA photolesions. The potential usefulness of this method for investigation of the spatial arrangement of chromosomes in the interphase nucleus is discussed
- …