Spontaneous Dissociation of 85Rb Feshbach Molecules

The spontaneous dissociation of 85Rb dimers in the highest lying vibrational level has been observed in the vicinity of the Feshbach resonance which was used to produce them. The molecular lifetime shows a strong dependence on magnetic field, varying by three orders of magnitude between 155.5 G and 162.2 G. Our measurements are in good agreement with theoretical predictions in which molecular dissociation is driven by inelastic spin relaxation. Molecule lifetimes of tens of milliseconds can be achieved close to resonance.Comment: 4 pages, 3 figure

Constraining the Surface Inhomogeneity and Settling Times of Metals on Accreting White Dwarfs

Due to the short settling times of metals in DA white dwarf atmospheres, any white dwarfs with photospheric metals must be actively accreting. It is therefore natural to expect that the metals may not be deposited uniformly on the surface of the star. We present calculations showing how the temperature variations associated with white dwarf pulsations lead to an observable diagnostic of the surface metal distribution, and we show what constraints current data sets are able to provide. We also investigate the effect that time-variable accretion has on the metal abundances of different species, and we show how this can lead to constraints on the gravitational settling times.Comment: 4 pages, 5 figures, accepted for publication in the Astrophysical Journal Letters, updated reference

Aerobee 350, flight 17.03 GE - Instrumentation information and calibration data

Airborne instrumentation system on Aerobee 350 sounding rocke

UBV photometry of asteroid 433 Eros

UBV observations of asteroid 433 Eros were conducted on 17 nights during the winter of 1974/75. The peak-to-peak amplitude of the light curve varied from about 0.3 mag to nearly 1.4 mag. The absolute V magnitude, extrapolated to zero phase, is 10.85. Phase coefficients of 0.0245 mag/degree, 0.0009 mag/degree, and 0.0004 mag/degree were derived for V, B-V, and U-B, respectively. The zero-phase color of Eros (B-V = 0.88, U-B = 0.50) is representative of an S (silicaceous) compositional type asteroid. The color does not vary with rotation. The photometric behavior of Eros can be modeled by a cylinder with rounded ends having an axial ratio of about 2.3:1

Absorption of pyrimidines, purines, and nucleosides by Co, Ni, Cu and Fe /III-montmorillonite /clay-organic studies XIII/

Absorption of pyrimidines, purines, and nucleosides by copper, nickel, cobalt, and iron montmorillonit

Mars: Seasonally variable radar reflectivity

Since reflectivity is a quantity characteristic of a given target at a particular geometry, the same (temporally unchanging) target examined by radar on different occasions should have the same reflectivity. Zisk and Mouginis-Mark noted that the average reflectivities in the Goldstone Mars data increased as the planet's S hemisphere passed from the late spring into early summer. The same data set was re-examined and the presence of the phenomenon of the apparent seasonal variability of radar reflectivity was confirmed. Two objections to these findings are addressed: (1) reflectivity variations may be present in the Goldstone Mars data as a result of an instrument/calibration error; and (2) the variations were introduced into the analysis through comparing reflectivities from two incompatible subsets of the data

Absorption of pyrimidines, purines and nucleosides by Li, Na, Mg, and Ca montmorillonite /clay organic studies 12/

Absorption of purines, pyrimidines, and nucleoside in aqueous solution by montmorillionite occurring as cation exchange reactio

Modeling the gravitational wave signature of neutron star black hole coalescences: PhenomNSBH

Accurate gravitational-wave (GW) signal models exist for black-hole binary (BBH) and neutron-star binary (BNS) systems, which are consistent with all of the published GW observations to date. Detections of a third class of compact-binary systems, neutron-star-black-hole (NSBH) binaries, have not yet been confirmed, but are eagerly awaited in the near future. For NSBH systems, GW models do not exist across the viable parameter space of signals. In this work we present the frequency-domain phenomenological model, PhenomNSBH, for GWs produced by NSBH systems with mass ratios from equal-mass up to 15, spin on the black hole up to a dimensionless spin of $|\chi|=0.5$, and tidal deformabilities ranging from 0 (the BBH limit) to 5000. We extend previous work on a phenomenological amplitude model for NSBH systems to produce an amplitude model that is parameterized by a single tidal deformability parameter. This amplitude model is combined with an analytic phase model describing tidal corrections. The resulting approximant is accurate enough to be used to measure the properties of NSBH systems for signal-to-noise ratios (SNRs) up to 50, and is compared to publicly-available NSBH numerical-relativity simulations and hybrid waveforms constructed from numerical-relativity simulations and tidal inspiral approximants. For most signals observed by second-generation ground-based detectors within this SNR limit, it will be difficult to use the GW signal alone to distinguish single NSBH systems from either BNSs or BBHs, and therefore to unambiguously identify an NSBH system

Optical Spectroscopy of K-selected Extremely Red Galaxies

We have obtained spectroscopic redshifts for 24 red galaxies from a sample with median Ks=18.7 and F814W - Ks > 4, using the Keck telescope. These EROshave high resolution morphologies from HST (Yan & Thompson 2003). Among the 24 redshifts, the majority (92%) are at $0.9 < z < 1.5$. We derived the rest-frame J-band luminosity function at $z_{median} =1.14$. Our result suggests that the luminosity evolution between bright EROs at $z\sim 1$ and the present-day $>$L$^*$ massive galaxies is at most about 0.7 magnitude. Combining the morphologies and deep spectroscopy revealed the following properties: (1) 86% of the spectra have absorption features from old stars, suggesting that the dominant stellar populations seen in the rest-frame UV are old stars. 50% of the sources have pure absorption lines, while the remaining 50% have emission lines, indicating recent star formation. We conclude that the color criterion for EROs is very effective in selecting old stellar populations at $z \sim 1$, and a large fraction of these systems with prominent old stellar populations also have recent star formation. (2) The 12 emission line systems have the same number of disk and bulge galaxies as in the remaining 12 pure absorption line systems. We conclude that spectral classes do not have a simple, direct correspondence with morphological types. (3) Three EROs could be isolated, pure passively evolving early-type galaxies at $z\sim 1$. This implies that only a small fraction (10%--15%) of early-type galaxies are formed in a rapid burst of star formation at high redshifts and evolved passively since then. (Abridged).Comment: 27 pages, 8 figures. Accepted for publication in Astronomical Journal, issue March 200