17,556 research outputs found
Satisfiability of CTL* with constraints
We show that satisfiability for CTL* with equality-, order-, and
modulo-constraints over Z is decidable. Previously, decidability was only known
for certain fragments of CTL*, e.g., the existential and positive fragments and
EF.Comment: To appear at Concur 201
Quasi-deterministic transport of Brownian particles in an oscillating periodic potential
We consider overdamped Brownian dynamics in a periodic potential with
temporally oscillating amplitude. We analyze the transport which shows
effective diffusion enhanced by the oscillations and derive approximate
expressions for the diffusion coefficient. Furthermore we analyze the effect of
the oscillating potential on the transport if additionally a constant force is
applied. We show the existence of synchronization regimes at which the
deterministic dynamics is in resonance with the potential oscillations giving
rise to transport with extremely low dispersion. We distinguish slow and fast
oscillatory driving and give analytical expressions for the mean velocity and
effective diffusion.Comment: submitted: Feb 12th, 201
Measures of galaxy dust and gas mass with Herschel photometry and prospects for ALMA
(Abridged) Combining the deepest Herschel extragalactic surveys (PEP,
GOODS-H, HerMES), and Monte Carlo mock catalogs, we explore the robustness of
dust mass estimates based on modeling of broad band spectral energy
distributions (SEDs) with two popular approaches: Draine & Li (2007, DL07) and
a modified black body (MBB). As long as the observed SED extends to at least
160-200 micron in the rest frame, M(dust) can be recovered with a >3 sigma
significance and without the occurrence of systematics. An average offset of a
factor ~1.5 exists between DL07- and MBB-based dust masses, based on consistent
dust properties. At the depth of the deepest Herschel surveys (in the GOODS-S
field) it is possible to retrieve dust masses with a S/N>=3 for galaxies on the
main sequence of star formation (MS) down to M(stars)~1e10 [M(sun)] up to z~1.
At higher redshift (z<=2) the same result is achieved only for objects at the
tip of the MS or lying above it. Molecular gas masses, obtained converting
M(dust) through the metallicity-dependent gas-to-dust ratio delta(GDR), are
consistent with those based on the scaling of depletion time, and on CO
spectroscopy. Focusing on CO-detected galaxies at z>1, the delta(GDR)
dependence on metallicity is consistent with the local relation. We combine
far-IR Herschel data and sub-mm ALMA expected fluxes to study the advantages of
a full SED coverage.Comment: Accepted for publication in Astronomy and Astrophysics. Some figures
have degraded quality for filesize reason
CTMC calculations of electron capture and ionization in collisions of multiply charged ions with elliptical Rydberg atoms
We have performed classical trajectory Monte Carlo (CTMC) studies of electron
capture and ionization in multiply charged (Q=8) ion-Rydberg atom collisions at
intermediate impact velocities. Impact parallel to the minor and to the major
axis, respectively, of the initial Kepler electron ellipse has been
investigated. The important role of the initial electron momentum distribution
found for singly charged ion impact is strongly disminished for higher
projectile charge, while the initial spatial distribution remains important for
all values of Q studied.Comment: 3 pages, 5 figure
Dietary Folic Acid Needs of High Lean Growth Pigs
Twelve sets of five littermate barrows were utilized to determine the folic acid needs of a high lean genetic strain of pigs experiencing a low level of immune system activation. Pigs were penned individually and given ad libitum access to a corn, soybean meal, 27% milk product diet containing dietary concentrations of folic acid equivalent to 100, 200, 300, 400, and 500% of the current NRC (2) estimated requirement for 11 to 22 lb pigs. Pigs were started on test when the average litter weight reached 19 pounds and were taken off test as individual pigs reached a body weight of 51 pounds. Dietary folic acid concentration did not alter daily body weight gain, daily feed intake, feed:gain ratio, or rates of body protein and fat accretion. Based on these data, a dietary folic acid concentration of 0.14 mg per pound of feed is adequate to support optimal growth and body nutrient accretion in high lean growth pigs fed corn-soybean meal-milk product diets from 19 to 51 pounds
Optical Versus Mid-Infrared Spectroscopic Classification of Ultraluminous Infrared Galaxies
The origin of huge infrared luminosities of ultraluminous infrared galaxies
(ULIGs) is still in question. Recently, Genzel et al. made mid-infrared (MIR)
spectroscopy of a large number of ULIGs and found that the major energy source
in them is massive stars formed in the recent starburst activity; i.e.,
70% -- 80% of the sample are predominantly powered by the starburst. However,
it is known that previous optical spectroscopic observations showed that the
majority of ULIGs are classified as Seyferts or LINERs (low-ionization nuclear
emission-line regions). In order to reconcile this difference, we compare types
of emission-line activity for a sample of ULIGs which have been observed in
both optical and MIR. We confirm the results of previous studies that the
majority of ULIGs classified as LINERs based on the optical emission-line
diagnostics turn to be starburst-dominated galaxies based on the MIR ones.
Since the MIR spectroscopy can probe more heavily-reddened, inner parts of the
ULIGs, it is quite unlikely that the inner parts are powered by the starburst
while the outer parts are powered by non-stellar ionization sources. The most
probable resolution of this dilemma is that the optical emission-line nebulae
with the LINER properties are powered predominantly by shock heating driven by
the superwind activity; i.e., a blast wave driven by a collective effect of a
large number of supernovae in the central region of galaxy mergers.Comment: 15 pages, 2 tables, and 3 eps figures. The Astrophysical Journal
(Part 1), in pres
The Signed Roman Domatic Number of a Digraph
Let be a finite and simple digraph with vertex set .A {\em signed Roman dominating function} on the digraph isa function such that for every , where consists of andall inner neighbors of , and every vertex for which has an innerneighbor for which . A set of distinct signedRoman dominating functions on with the property that for each, is called a {\em signed Roman dominating family} (of functions) on . The maximumnumber of functions in a signed Roman dominating family on is the {\em signed Roman domaticnumber} of , denoted by . In this paper we initiate the study of signed Romandomatic number in digraphs and we present some sharp bounds for . In addition, wedetermine the signed Roman domatic number of some digraphs. Some of our results are extensionsof well-known properties of the signed Roman domatic number of graphs
Local Swift-BAT active galactic nuclei prefer circumnuclear star formation
We use Herschel data to analyze the size of the far-infrared 70micron
emission for z<0.06 local samples of 277 hosts of Swift-BAT selected active
galactic nuclei (AGN), and 515 comparison galaxies that are not detected by
BAT. For modest far-infrared luminosities 8.5<log(LFIR)<10.5, we find large
scatter of half light radii Re70 for both populations, but a typical Re70 <~ 1
kpc for the BAT hosts that is only half that of comparison galaxies of same
far-infrared luminosity. The result mostly reflects a more compact distribution
of star formation (and hence gas) in the AGN hosts, but compact AGN heated dust
may contribute in some extremely AGN-dominated systems. Our findings are in
support of an AGN-host coevolution where accretion onto the central black hole
and star formation are fed from the same gas reservoir, with more efficient
black hole feeding if that reservoir is more concentrated. The significant
scatter in the far-infrared sizes emphasizes that we are mostly probing spatial
scales much larger than those of actual accretion, and that rapid accretion
variations can smear the distinction between the AGN and comparison categories.
Large samples are hence needed to detect structural differences that favour
feeding of the black hole. No size difference AGN host vs. comparison galaxies
is observed at higher far-infrared luminosities log(LFIR)>10.5 (star formation
rates >~ 6 Msun/yr), possibly because these are typically reached in more
compact regions in the first place.Comment: 7 pages, 3 figures, accepted for publication in Astronomy &
Astrophysic
A Compact Starburst Core in the Dusty Lyman Break Galaxy Westphal-MD11
Using the IRAM Plateau de Bure Interferometer, we have searched for CO(3-2)
emission from the dusty Lyman break galaxy Westphal-MD11 at z = 2.98. Our
sensitive upper limit is surprisingly low relative to the system's 850 um flux
density and implies a far-IR/CO luminosity ratio as elevated as those seen in
local ultraluminous mergers. We conclude that the observed dust emission must
originate in a compact structure radiating near its blackbody limit and that a
relatively modest molecular gas reservoir must be fuelling an intense nuclear
starburst (and/or deeply buried active nucleus) that may have been triggered by
a major merger. In this regard, Westphal-MD11 contrasts strikingly with the
lensed Lyman break galaxy MS1512-cB58, which is being observed apparently
midway through an extended episode of more quiescent disk star formation.Comment: 5 pages, 1 figure (emulateapj), accepted by ApJ
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