Probing ~100 AU Intergalactic MgII Absorbing "Cloudlets" with Quasar Microlensing

Intergalactic MgII absorbers are known to have structures down to scales ~ 10^{2.5} pc, and there are now indications that they may be fragmented on scales <~ 10^{-2.5} pc (Hao et al., astro-ph/0612409). When a lensed quasar is microlensed, the micro-images of the quasar experience creation, destruction, distortion, and drastic astrometric changes during caustic-crossing. I show that quasar microlensing can effectively probe MgII and other absorption "cloudlets" with sizes ~ 10^{-4.0} - 10^{-2.0} pc by inducing significant spectral variability on the timescales of months to years. With numerical simulations, I demonstrate the feasibility of applying this method to Q2237+0305, and I show that high-resolution spectra of this quasar in the near future would provide a clear test of the existence of such metal-line absorption "cloudlets" along the quasar sight line.Comment: 13 pages, 2 figures, ApJ, submitted; for PDF file with high-res figures, see http://www.astronomy.ohio-state.edu/~dong/mg2/mg2.pd

Microlensing of Lensed Supernovae

Given the number of recently discovered galaxy-galaxy lens systems, we anticipate that a gravitationally lensed supernova will be observed within the next few years. We explore the possibility that stars in the lens galaxy will produce observable microlensing fluctuations in lensed supernova light curves. For typical parameters, we predict that ~70% of lensed SNe will show microlensing fluctuations > 0.5 mag, while ~25% will have fluctuations > 1 mag. Thus microlensing of lensed supernova will be both ubiquitous and observable. Additionally, we show that microlensing fluctuations will complicate measurements of time delays from multiply imaged supernovae: time delays accurate to better than a few days will be difficult to obtain. We also consider prospects for extracting the lens galaxy's stellar mass fraction and mass function from microlensing fluctuations via a new statistical measure, the time-weighted light curve derivative.Comment: 13 pages, emulateapj format; accepted in ApJ; expanded discussion of time delay uncertaintie

How can we test seesaw experimentally?

The seesaw mechanism for the small neutrino mass has been a popular paradigm, yet it has been believed that there is no way to test it experimentally. We present a conceivable outcome from future experiments that would convince us of the seesaw mechanism. It would involve a variety of data from LHC, ILC, cosmology, underground, and low-energy flavor violation experiments to establish the case.Comment: 5 pages, 4 figure

A method to measure a relative transverse velocity of source-lens-observer system using gravitational lensing of gravitational waves

Gravitational waves propagate along null geodesics like light rays in the geometrical optics approximation, and they may have a chance to suffer from gravitational lensing by intervening objects, as is the case for electromagnetic waves. Long wavelength of gravitational waves and compactness of possible sources may enable us to extract information in the interference among the lensed images. We point out that the interference term contains information of relative transverse velocity of the source-lens-observer system, which may be obtained by possible future space-borne gravitational wave detectors such as BBO/DECIGO.Comment: 27 pages, 9 figures. Accepted for publication in Physical Review

Talented and gifted programs in the middle school : critical components

As middle school educators and teachers of the gifted and talented continue to debate issues such as equity vs. excellence, homogeneous vs. heterogeneous grouping, and cognitive vs. affective education, the needs of gifted and talented middle school students in the general education classroom appear to be ignored. This paper reviewed current literature relating to the needs of gifted and talented pre-adolescents in the middle school setting in order to determine what were the critical components necessary for meeting their unique needs in the general education classroom. From the reviewed literature, critical components identified include content differentiation, teaching strategies, grouping for instruction, and addressing the social-emotional needs of acceptance and self-esteem. The paper closes with a discussion of conclusions which may be drawn from the literature and recommendations for further study

Lensing and the Centers of Distant Early-Type Galaxies

Gravitational lensing provides a unique probe of the inner 10-1000 pc of distant galaxies (z=0.2-1). Lens theory predicts that every strong lens system should have a faint image near the center of the lens galaxy, which should be visible in radio lenses but have not been observed. We study these ``core'' images using models derived from the stellar distributions in nearby early-type galaxies. We find that realistic galaxies predict a remarkably wide range of core images, with lensing magnifications spanning some six orders of magnitude. More concentrated galaxies produce fainter core images, although not with any simple, quantitative, model independent relation. Some real galaxies have diffuse cores and predict bright core images (magnification mu>~0.1), but more common are galaxies that predict faint core images (mu<~0.001). Thus, stellar mass distributions alone are probably concentrated enough to explain the lack of observed core images, and may require observational sensitivity to improve by an order of magnitude before detections of core images become common. Two-image lenses will tend to have brighter core images than four-image lenses, so they will be the better targets for finding core images and exploiting these tools for studying the central mass distributions of distant galaxies.Comment: 13 pages, emulateapj; submitted to Ap