Cheap Space-Based Microlens Parallaxes for High-Magnification Events

We show that for high-magnification (Amax > 100) microlensing events, accurate microlens parallaxes can be obtained from three or fewer photometric measurements from a small telescope on a satellite in solar orbit at ~1 AU from Earth. This is 1--2 orders of magnitude less observing resources than are required for standard space-based parallaxes. Such microlens parallax measurements would yield accurate mass and distance measurements to the lens for all cases in which finite-source effects were observed from the ground over peak. This would include virtually all high-magnification events with detected planets and a substantial fraction of those without. Hence it would permit accurate estimates of the Galactic distribution of planets.Comment: 6 pages, 1 figure, submitted to ApJ Letter

Can Heavy WIMPs Be Captured by the Earth?

If weakly interacting massive particles (WIMPs) in bound solar orbits are systematically driven into the Sun by solar-system resonances (as Farinella et al. have shown is the case for many Earth-crossing asteroids), then the capture of high-mass WIMPs by the Earth would be affected dramatically because high-mass WIMPs are captured primarily from bound orbits. WIMP capture would be eliminated for M_x>630 GeV and would be highly suppressed for M_x>~150 GeV. Annihilation of captured WIMPs and anti-WIMPs is expected to give rise to neutrinos coming from the Earth's center. The absence of such a neutrino signal has been used to place limits on WIMP parameters. At present, one does not know if typical WIMP orbits are in fact affected by these resonances. Until this question is investigated and resolved, one must (conservatively) assume that they are. Hence, limits on high-mass WIMP parameters are significantly weaker than previously believed.Comment: 8 pages + 1 figure. Submitted to Ap

Limits on the Gravity Wave Background From Microlensed Quasars

The paper previously submitted under this title is incorrect in that it drastically overestimates the cumulative deflection due to a gravitational wave (GW) background. Avi Loeb gives a simple argument that there can be no $(D\omega)^{1/2}$ enhancement: since the problem is linear in $h$, one can decompose the GWs into plane waves and for each of these there is no enhancement.Comment: This paper was incorrect in that it drastically overestimated the cumulative deflection due to a gravitational wave background. Withdraw

Are We Happy Yet?: Re-evaluating the Evaluation of Indigenous Community Development

As I was working on research into Indigenous community development, I wanted to get an overview of how things are going - are projects improving well-being? What is working and what isn\u27t? I found I couldn\u27t get a clear multi-dimensional picture. So I had to wonder, about evaluation criteria and what the alternatives were. How can we, as academics and researchers and allies, make sense of the available information in such a way that our work is meaningful to the Indigenous communities we work with

Microlensing and the Stellar Mass Function

Traditional approaches to measuring the stellar mass function (MF) are fundamentally limited because objects are detected based on their luminosity, not their mass. These methods are thereby restricted to luminous and relatively nearby stellar populations. Gravitational microlensing promises to revolutionize our understanding of the MF. It is already technologically feasible to measure the MFs of the Galactic disk and Galactic bulge as functions of position, although the actual execution of this program requires aggressive ground-based observations including infrared interferometry, as well as the launching of a small satellite telescope. Rapid developments in microlensing, including the new technique of ``pixel lensing'' of unresolved stars, will allow one to probe the MF and luminosity function of nearby galaxies. Such observations of M31 are already underway, and pixel-lensing observations of M87 with the {\it Hubble Space Telescope} would permit detection of dark intra-cluster objects in Virgo. Microlensing techniques can also be applied to investigate the star-formation history of the universe and to search for planets with masses as small as the Earth's. Based on an invited talk at the January 1996 AAS meeting in San Antonio. PASP (June 1996) in press, (c) ASP, reproduced with permission.Comment: 31 pages with 7 embedded figures. PASP (June 1996) in press, (c) ASP, reproduced with permissio

Coherence for Categorified Operadic Theories

It has long been known that every weak monoidal category A is equivalent via monoidal functors and monoidal natural transformations to a strict monoidal category st(A). We generalise the definition of weak monoidal category to give a definition of weak P-category for any strongly regular (operadic) theory P, and show that every weak P-category is equivalent via P-functors and P-transformations to a strict P-category. This strictification functor is then shown to have an interesting universal property.Comment: 13 pages, 1 figure. Presented at 82nd PSSL, Glasgow, May 200