2,438 research outputs found

### Lattice electrons in constant magnetic field: Bethe like ansatz

We use the functional representation of Heisenberg-Weyl group and obtain
equation for the spectrum of the model, which is more complicated than Bethes
ones, but can be written explicitly through theta functions.Comment: 8 pages, LATE

### Conformal mechanics inspired by extremal black holes in d=4

A canonical transformation which relates the model of a massive relativistic
particle moving near the horizon of an extremal black hole in four dimensions
and the conventional conformal mechanics is constructed in two different ways.
The first approach makes use of the action-angle variables in the angular
sector. The second scheme relies upon integrability of the system in the sense
of Liouville.Comment: V2: presentation improved, new material and references added; the
version to appear in JHE

### Exact and quasiexact solvability of second-order superintegrable quantum systems: I. Euclidean space preliminaries

We show that second-order superintegrable systems in two-dimensional and three-dimensional Euclidean space generate both exactly solvable (ES) and quasiexactly solvable (QES) problems in quantum mechanics via separation of variables, and demonstrate the increased insight into the structure of such problems provided by superintegrability. A principal advantage of our analysis using nondegenerate superintegrable systems is that they are multiseparable. Most past separation of variables treatments of QES problems via partial differential equations have only incorporated separability, not multiseparability. Also, we propose another definition of ES and QES. The quantum mechanical problem is called ES if the solution of Schrödinger equation can be expressed in terms of hypergeometric functions mFn and is QES if the Schrödinger equation admits polynomial solutions with coefficients necessarily satisfying a three-term or higher order of recurrence relations. In three dimensions we give an example of a system that is QES in one set of separable coordinates, but is not ES in any other separable coordinates. This example encompasses Ushveridze's tenth-order polynomial QES problem in one set of separable coordinates and also leads to a fourth-order polynomial QES problem in another separable coordinate set

### Paired galaxies with different activity levels and their supernovae

We investigate the influence of close neighbor galaxies on the properties of
supernovae (SNe) and their host galaxies using 56 SNe located in pairs of
galaxies with different levels of star formation (SF) and nuclear activity. The
statistical study of SN hosts shows that there is no significant difference
between morphologies of hosts in our sample and the larger general sample of SN
hosts in the Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8). The mean
distance of type II SNe from nuclei of hosts is greater by about a factor of 2
than that of type Ibc SNe. The distributions and mean distances of SNe are
consistent with previous results compiled with the larger sample. For the first
time it is shown that SNe Ibc are located in pairs with significantly smaller
difference of radial velocities between components than pairs containing SNe Ia
and II. We consider this as a result of higher star formation rate (SFR) of
these closer systems of galaxies. SN types are not correlated with the
luminosity ratio of host and neighbor galaxies in pairs. The orientation of SNe
with respect to the preferred direction toward neighbor galaxy is found to be
isotropic and independent of kinematical properties of the galaxy pair.Comment: 10 pages, 2 figures, 5 tables, online data, published in Astrophysics
and Space Scienc

### On the Nature of Unconfirmed Supernovae

We study the nature of 39 unconfirmed supernovae (SNe) from the sky area
covered by the Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8), using
available photometric and imaging data and intensive literature search. We
confirm that 21 objects are real SNe, 2 are Galactic stars, 4 are probable SNe,
and 12 remain unconfirmed events. The probable types for 4 objects are
suggested: 3 SNe are of probable type Ia, and SN 1953H is probable type II SN.
In addition, we identify the host galaxy of SN 1976N and correct the
offsets/coordinates of SNe 1958E, 1972F, and 1976N.Comment: 9 pages, 4 figures, 5 tables, published in Astrophysics (English
translation of Astrofizika

### Supernovae in paired galaxies

We investigate the influence of close neighbor galaxies on the properties of
supernovae (SNe) and their host galaxies using 56 SNe located in pairs of
galaxies with different levels of star formation (SF) and nuclear activity. The
mean distance of type II SNe from nuclei of hosts is greater by about a factor
of 2 than that of type Ibc SNe. The distributions and mean distances of SNe are
consistent with previous results compiled with the larger sample. For the first
time it is shown that SNe Ibc are located in pairs with significantly smaller
difference of radial velocities between components than pairs containing SNe Ia
and II. We consider this as a result of higher star formation rate (SFR) of
these closer systems of galaxies.Comment: 2 pages. arXiv admin note: text overlap with arXiv:1312.494

### Modified Spin Wave Analysis of Low Temperature Properties of Spin-1/2 Frustrated Ferromagnetic Ladder

Low temperature properties of the spin-1/2 frustrated ladder with
ferromagnetic rungs and legs, and two different antiferromagnetic next nearest
neighbor interaction are investigated using the modified spin wave
approximation in the region with ferromagnetic ground state. The temperature
dependence of the magnetic susceptibility and magnetic structure factors is
calculated. The results are consistent with the numerical exact diagonalization
results in the intermediate temperature range. Below this temperature range,
the finite size effect is significant in the numerical diagonalization results,
while the modified spin wave approximation gives more reliable results. The low
temperature properties near the limit of the stability of the ferromagnetic
ground state are also discussed.Comment: 9 pages, 8 figure

### Supernovae and their host galaxies - IV. The distribution of supernovae relative to spiral arms

Using a sample of 215 supernovae (SNe), we analyze their positions relative
to the spiral arms of their host galaxies, distinguishing grand-design (GD)
spirals from non-GD (NGD) galaxies. We find that: (1) in GD galaxies, an offset
exists between the positions of Ia and core-collapse (CC) SNe relative to the
peaks of arms, while in NGD galaxies the positions show no such shifts; (2) in
GD galaxies, the positions of CC SNe relative to the peaks of arms are
correlated with the radial distance from the galaxy nucleus. Inside (outside)
the corotation radius, CC SNe are found closer to the inner (outer) edge. No
such correlation is observed for SNe in NGD galaxies nor for SNe Ia in either
galaxy class; (3) in GD galaxies, SNe Ibc occur closer to the leading edges of
the arms than do SNe II, while in NGD galaxies they are more concentrated
towards the peaks of arms. In both samples of hosts, the distributions of SNe
Ia relative to the arms have broader wings. These observations suggest that
shocks in spiral arms of GD galaxies trigger star formation in the leading
edges of arms affecting the distributions of CC SNe (known to have short-lived
progenitors). The closer locations of SNe Ibc vs. SNe II relative to the
leading edges of the arms supports the belief that SNe Ibc have more massive
progenitors. SNe Ia having less massive and older progenitors, have more time
to drift away from the leading edge of the spiral arms.Comment: 19 pages, 10 figures, 11 tables, resubmitted to MNRAS after
addressing referee's comment

### Relative frequencies of supernovae versus properties of spiral hosts

In this work, we present an analysis of SNe number ratios in spiral galaxies
with different morphological subtypes, luminosities, sSFR, and metallicities,
to provide important information about the physical properties of the
progenitor populations.Comment: 2 pages, 1 figur

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