668 research outputs found
Properties of Type II Plateau Supernova SNLS-04D2dc: Multicolor Light Curves of Shock Breakout and Plateau
Shock breakout is the brightest radiative phenomenon in a Type II supernova
(SN). Although it was predicted to be bright, the direct observation is
difficult due to the short duration and X-ray/ultraviolet-peaked spectra. First
entire observations of the shock breakouts of Type II Plateau SNe (SNe IIP)
were reported in 2008 by ultraviolet and optical observations by the {\it
GALEX} satellite and supernova legacy survey (SNLS), named SNLS-04D2dc and
SNLS-06D1jd. We present multicolor light curves of a SN IIP, including the
shock breakout and plateau, calculated with a multigroup radiation
hydrodynamical code {\sc STELLA} and an evolutionary progenitor model. The
synthetic multicolor light curves reproduce well the observations of
SNLS-04D2dc. This is the first study to reproduce the ultraviolet light curve
of the shock breakout and the optical light curve of the plateau consistently.
We conclude that SNLS-04D2dc is the explosion with a canonical explosion energy
ergs and that its progenitor is a star with a zero-age
main-sequence mass and a presupernova radius . The
model demonstrates that the peak apparent -band magnitude of the shock
breakout would be mag if a SN being identical to
SNLS-04D2dc occurs at a redshift , which can be reached by 8m-class
telescopes. The result evidences that the shock breakout has a great potential
to detect SNe IIP at z\gsim1.Comment: 5 pages, 5 figures. Accepted for publication in the Astrophysical
Journal Letter
Shock Breakout in Type II Plateau Supernovae: Prospects for High Redshift Supernova Surveys
Shock breakout is the brightest radiative phenomenon in a supernova (SN) but
is difficult to be observed owing to the short duration and X-ray/ultraviolet
(UV)-peaked spectra. After the first observation from the rising phase reported
in 2008, its observability at high redshift is attracting enormous attention.
We perform multigroup radiation hydrodynamics calculations of explosions for
evolutionary presupernova models with various main-sequence masses , metallicities , and explosion energies . We present multicolor
light curves of shock breakout in Type II plateau SNe, being the most frequent
core-collapse SNe, and predict apparent multicolor light curves of shock
breakout at various redshifts . We derive the observable SN rate and
reachable redshift as functions of filter and limiting magnitude by taking into account an initial mass function, cosmic star formation
history, intergalactic absorption, and host galaxy extinction. We propose a
realistic survey strategy optimized for shock breakout. For example, the
-band observable SN rate for mag is 3.3 SNe
degree day and a half of them locates at . It is clear
that the shock breakout is a beneficial clue to probe high- core-collapse
SNe. We also establish ways to identify shock breakout and constrain SN
properties from the observations of shock breakout, brightness, time scale, and
color. We emphasize that the multicolor observations in blue optical bands with
hour intervals, preferably over continuous nights, are essential
to efficiently detect, identify, and interpret shock breakout.Comment: 26 pages, 23 figures. Accepted for publication in the Astrophysical
Journal Supplement Serie
Discovery of a Gravitationally Lensed Quasar from the Sloan Digital Sky Survey: SDSS J133222.62+034739.9
We report the discovery of the two-image gravitationally lensed quasar SDSS
J133222.62+034739.9 (SDSS J1332+0347) with an image separation of
Delta_theta=1.14". This system consists of a source quasar at z_s=1.445 and a
lens galaxy at z_l=0.191. The agreement of the luminosity, ellipticity and
position angle of the lens galaxy with those expected from lens model confirms
the lensing hypothesis.Comment: 16 pages, 4 figures, the Astronomical Journal accepte
Large Polarization Degree of Comet 2P/Encke Continuum Based on Spectropolarimetric Signals During Its 2017 Apparition
Spectropolarimetry is a powerful technique for investigating the physical
properties of gas and solid materials in cometary comae without mutual
contamination, but there have been few spectropolarimetric studies to extract
each component. We attempt to derive the continuum polarization degree of comet
2P/Encke, free from influence of molecular emissions. The target is unique in
that it has an orbit dynamically decoupled from Jupiter like main-belt
asteroids, while ejecting gas and dust like ordinary comets. We observed the
comet using the Higashi-Hiroshima Optical and Near-Infrared Camera attached to
the Cassegrain focus of the 150-cm Kanata telescope on UT 2017 February 21 when
the comet was at the solar phase angle of 75.7 deg. We find that the continuum
polarization degree with respect to the scattering plane is 33.8+/-2.7 % at the
effective wavelength of 0.815 um, which is significantly higher than those of
cometary dust in a high-Pmax group at similar phase angles. Assuming that an
ensemble polarimetric response of 2P/Encke's dust as a function of phase angle
is morphologically similar with those of other comets, its maximum polarization
degree is estimated to > 40 % at the phase angle of ~100 deg. In addition, we
obtain the polarization degrees of the C2 swan bands (0.51-0.56 um), the NH2
alpha bands (0.62-0.69 um) and the CN-red system (0.78-0.94 um) in a range of
3-19 %, which depend on the molecular species and rotational quantum numbers of
each branch. The polarization vector aligns nearly perpendicularly to the
scattering plane with the average of 0.4 deg over a wavelength range of
0.50-0.97 um. From the observational evidence, we conjecture that the large
polarization degree of 2P/Encke would be attributable to a dominance of large
dust particles around the nucleus, which have remained after frequent
perihelion passages near the Sun.Comment: 9 pages, 4 figures, accepted for publication in Astronomy &
Astrophysic
Derivation of the Supermolecular Interaction Energy from the Monomer Densities in the Density Functional Theory
The density functional theory (DFT) interaction energy of a dimer is
rigorously derived from the monomer densities. To this end, the supermolecular
energy bifunctional is formulated in terms of mutually orthogonal sets of
orbitals of the constituent monomers. The orthogonality condition is preserved
in the solution of the Kohn-Sham equations through the Pauli blockade method.
Numerical implementation of the method provides interaction energies which
agree with those obtained from standard supermolecular calculations within less
than 0.1% error for three example functionals: Slater-Dirac, PBE0 and B3LYP,
and for two model van der Waals dimers: Ne2 and (C2H4)2, and two model H-bond
complexes: (HF)2 and (NH3)2.Comment: 6 pages, 1 figure, REVTeX
The Subaru/XMM-Newton Deep Survey (SXDS) - VI. Properties of Active Galactic Nuclei Selected by Optical Variability
We present the properties of active galactic nuclei (AGN) selected by optical
variability in the Subaru/XMM-Newton Deep Field (SXDF). Based on the locations
of variable components and light curves, 211 optically variable AGN were
reliably selected. We made three AGN samples; X-ray detected optically
non-variable AGN (XA), X-ray detected optically variable AGN (XVA), and X-ray
undetected optically variable AGN (VA). In the VA sample, we found a bimodal
distribution of the ratio between the variable component flux and the host
flux. One of these two components in the distribution, a class of AGN with a
faint variable component mag in bright host galaxies
mag, is not seen in the XVA sample. These AGN are expected to have
low Eddington ratios if we naively consider a correlation between bulge
luminosity and black hole mass. These galaxies have photometric redshifts
and we infer that they are low-luminosity AGN with
radiatively inefficient accretion flows (RIAFs). The properties of the XVA and
VA objects and the differences from those of the XA objects can be explained
within the unified scheme for AGN. Optical variability selection for AGN is an
independent method and could provide a complementary AGN sample which even deep
X-ray surveys have not found.Comment: 9 pages, 10 figures, accepted for publication in Ap
SN 2016jhj at redshift 0.34: extending the Type II supernova Hubble diagram using the standard candle method
Although Type Ia supernova cosmology has now reached a mature state, it is important to develop as many independent methods as possible to understand the true nature of dark energy. Recent studies have shown that Type II supernovae (SNe II) offer such a path and could be used as alternative distance indicators. However, the majority of these studies were unable to extend the Hubble diagram above redshift z = 0.3 because of observational limitations. Here, we show that we are now ready to move beyond low redshifts and attempt high-redshift (z ≳ 0.3) SN II cosmology as a result of new-generation deep surveys such as the Subaru/Hyper Suprime-Cam survey. Applying the ´standard candle method´ to SN 2016jhj (z = 0.3398 ± 0.0002; discovered by HSC) together with a low-redshift sample, we are able to construct the highest-redshift SN II Hubble diagram to date with an observed dispersion of 0.27 mag (i.e. 12-13 per cent in distance). This work demonstrates the bright future of SN II cosmology in the coming era of large, wide-field surveys like that of the Large Synoptic Survey Telescope.Fil: de Jaeger, T.. University of California at Berkeley; Estados UnidosFil: Galbany, L.. University of Pittsburgh at Johnstown; Estados UnidosFil: Filippenko, A. V.. University of California at Berkeley; Estados UnidosFil: González Gaitán, S.. Universidad de Chile; ChileFil: Yasuda, N.. University of Tokio; JapónFil: Maeda, K.. University of Tokio; JapónFil: Tanaka, M.. University of Tokio; JapónFil: Morokuma, T.. University of Tokio; JapónFil: Moriya, T. J.. National Astronomical Observatory of Japan; JapónFil: Tominaga, N.. University of Tokyo; JapónFil: Nomoto, Ken’ichi. University of Tokyo; JapónFil: Komiyama, Y.. National Astronomical Observatory of Japan; JapónFil: Anderson, J. P.. European Southern Observatory; ChileFil: Brink, T. G.. University of California at Berkeley; Estados UnidosFil: Carlberg, R. G.. University of Toronto; CanadáFil: Folatelli, Gaston. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. University of Tokyo; JapónFil: Hamuy, M.. Universidad de Chile; ChileFil: Pignata, G.. Universidad Andrés Bello; ChileFil: Zheng, W.. University of California at Berkeley; Estados Unido
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