The Shape of M Dwarf Flares in Kepler Light Curves

Ultra-precise light curves from Kepler provide the best opportunity to determine rates and statistical properties of stellar flares. From 11 months of data on the active M4 dwarf, GJ 1243, we have built the largest catalog of flares for a single star: over 6100 events. Combining 885 of our most pristine flares, we generated an empirical white-light flare template. This high-fidelity template shows a rapid initial rise, and two distinct exponential cooling phases. This template is useful in constraining flare energies and for improved flare detection in many surveys. Complex, multi-peaked events are more common for higher energy flares in this sample. Using our flare template we characterize the structure of complex events. In this contributed talk, I presented results from our boutique study of GJ 1243, and described an expanded investigation of the structure of complex flares and their connection to solar events.Comment: 6 pages, 6 figures, to appear in the Proceedings of "Solar and Stellar Flares and their Effects on Planets Proceedings", IAU Symposium No. 320, 2015. Flare sample is available online http://github.com/jradavenport/GJ1243-Flare

The Kepler Catalog of Stellar Flares

A homogeneous search for stellar flares has been performed using every available Kepler light curve. An iterative light curve de-trending approach was used to filter out both astrophysical and systematic variability to detect flares. The flare recovery completeness has also been computed throughout each light curve using artificial flare injection tests, and the tools for this work have been made publicly available. The final sample contains 851,168 candidate flare events recovered above the 68% completeness threshold, which were detected from 4041 stars, or 1.9% of the stars in the Kepler database. The average flare energy detected is ~$10^{35}$ erg. The net fraction of flare stars increases with $g-i$ color, or decreasing stellar mass. For stars in this sample with previously measured rotation periods, the total relative flare luminosity is compared to the Rossby number. A tentative detection of flare activity saturation for low-mass stars with rapid rotation below a Rossby number of ~0.03 is found. A power law decay in flare activity with Rossby number is found with a slope of -1, shallower than typical measurements for X-ray activity decay with Rossby number.Comment: 15 pages, 8 figures, ApJ accepted. Code is available online: http://github.com/jradavenport/appaloos

Understanding the entanglement entropy and spectra of 2D quantum systems through arrays of coupled 1D chains

We describe an algorithm for studying the entanglement entropy and spectrum of 2D systems, as a coupled array of $N$ one dimensional chains in their continuum limit. Using the algorithm to study the quantum Ising model in 2D, (both in its disordered phase and near criticality) we confirm the existence of an area law for the entanglement entropy and show that near criticality there is an additive piece scaling as $c_{eff}\log (N)/6$ with $c_{eff} \approx 1$. \textcolor{black}{Studying the entanglement spectrum, we show that entanglement gap scaling can be used to detect the critical point of the 2D model. When short range (area law) entanglement dominates we find (numerically and perturbatively) that this spectrum reflects the energy spectrum of a single quantum Ising chain.Comment: 8 pages (4 + supplementary material). 10 figure

Visualising mixed reality simulation for multiple users

Cowling, MA ORCiD: 0000-0003-1444-1563Blended reality seeks to encourage co-presence in the classroom, blending student experience across virtual and physical worlds. In a similar way, Mixed Reality, a continuum between virtual and real environments, is now allowing learners to work in both the physical and the digital world simultaneously, especially when combined with an immersive headset experience. This experience provides innovative new experiences for learning, but faces the challenge that most of these experiences are single user, leaving others outside the new environment. The question therefore becomes, how can a mixed reality simulation be experienced by multiple users, and how can we present that simulation effectively to users to create a true blended reality environment? This paper proposes a study that uses existing screen production research into the user and spectator to produce a mixed reality simulation suitable for multiple users. A research method using Design Based Research is also presented to assess the usability of the approach

Cavity driven by a single photon: conditional dynamics and non-linear phase shift

We apply the stochastic master equations (quantum filter) derived by Gough et al. (Proc. 50th IEEE Conference on Decision and Control, 2011) to a system consisting of a cavity driven by a multimode single photon field. In particular, we analyse the conditional dynamics for the problem of cross phase modulation in a doubly resonant cavity. Through the exact integration of the stochastic equations, our results reveal features of the problem unavailable from previous models

Tracing the Dynamics of Disk Galaxies with Optical and IR Surface Photometry: Color Gradients in M99

We present optical and IR surface photometry of M99 (NGC 4254) at g, r_S i, J and K'. We also present a K' image of M51 (NGC 5194) for comparison. Fourier decomposition of the disk light reveals that the radial distribution of power depends on wavelength, which in turn implies that the spiral structure traced in the visual (i.e. young population I and dust) is different from the one detected at 2 microns (i.e. old stellar disk). We observe radial modulation of the power and a dependency of power with wavelength that are consistent with modal theory of spiral structure. A central motivation for our research is the fundamental idea of density wave theory that the passage of a spiral density wave triggers star formation. We have found a stellar population age gradient consistent with this scenario in a reddening-free, red supergiant-sensitive, Q-like photometric parameter at 6 kpc galactocentric distance across one of the arms of M99. We rule out that the change in this parameter, Q(r_SJgi), across the arm is mainly due to dust. The difference in Q(r_SJgi) going from the interarm regions to the arms also indicates that arms cannot be due exclusively to crowding of stellar orbits. We present the first measurement of Omega_p, the angular speed of the spiral pattern, and of the location of the corotation radius, derived from the drift velocity of the young stars away from their birth site. The measured Q(r_SJgi) implies a star formation rate for M99 within the range of 10-20 M_odot/yr; a disk stellar mass surface density of ~80 M_odot/pc^2; and a maximum contribution of ~20 percent from red supergiants to the K' light in a small region, and much smaller on average. We measure a K' arm--interarm contrast of 2-3, too high for M99 to be a truly isolated galaxy.Comment: 25 pages of uuencoded, compressed Postscript (text only). To appear in 1 April 1996 issue of The Astrophysical Journal. Also available, together with 2 uuencoded, compressed PostScript files with 10 figures each, at http://astro.berkeley.edu/preprints.htm

Anatomy and Histology of the Male Reproductive Complex of the Onion Maggot Fly, \u3ci\u3eDelia Antiqua\u3c/i\u3e, (Diptera: Anthomyiidae) Including Some Comparisons With \u3ci\u3eD. Platura\u3c/i\u3e and \u3ci\u3eD. Radicum\u3c/i\u3e

In Delia antiqua (Meigen) (Diptera: Anthomyiidae), the male reproductive complex is composed of a pair of testes, paired vas deferens connecting the testes to the anterior ejaculatory duct, and a pair of paragonial (accessory) glands. Each D. antiqua paragonial gland consists of a single layer of secretory epithelial cells surrounded by a thin sheath of muscle tissue. The paragonial cells appear to be largely homogeneous in form, however a minor number of cells exhibit unique staining characteristics distinct from the main cells of the gland. This is preliminary evidence for a secondary cell type as has been found for Drosophila and Aedes paragonial glands. In contrast to the testis and vas deferens, where most of the growth occurs during the pupal stage, the D. antiqua paragonial glands expanded markedly due to secretory accumulation during the first days of adult life. Based on histochemical analyses, the paragonial secretion contained abundant protein, with evidence of glycoprotein. The reproductive complex in all three Delia species (D. antiqua, D. radicum (Bouche) and D. platura (Meigen)) appears similar, with the exception of size differences and timing of paragonial secretory accumulation and sperm maturation. Paragonial glands of D. radicum were the largest in both length and width, and only this species possessed abundant sperm upon eclosion. Of the three species, D. radicum appears most capable of mating immediately after eclosion based on the histology of its reproductive complex, which is consistent with biochemical and behavioral observations made earlier in this laboratory

An Infrared Camera for Leuschner Observatory and the Berkeley Undergraduate Astronomy Lab

We describe the design, fabrication, and operation of an infrared camera which is in use at the 30-inch telescope of the Leuschner Observatory. The camera is based on a Rockwell PICNIC 256 x 256 pixel HgCdTe array, which is sensitive from 0.9-2.5 micron. The primary purpose of this telescope is for undergraduate instruction. The cost of the camera has been minimized by using commercial parts whereever practical. The camera optics are based on a modified Offner relay which forms a cold pupil where stray thermal radiation from the telescope is baffled. A cold, six-position filter wheel is driven by a cryogenic stepper motor, thus avoiding any mechanical feed throughs. The array control and readout electronics are based on standard PC cards; the only custom component is a simple interface card which buffers the clocks and amplifies the analog signals from the array.Comment: 13 pages, 17 figures. Submitted to Publications of the Astronomical Society of the Pacific: 2001 Jan 10, Accepted 2001 Jan 1

Forward-scatter radiant mapping

Forward-scatter systems have been much neglected for the study of meteors and meteor streams. A great deal of this neglect stems from the complicated geometry which has made the interpretation of results difficult in the past. This no longer presents a problem because of the computer power now available. There are practical advantages in using forward-scatter in that low-power transmitters are much easier to handle than the high-power ones used in pulsed back-scatter radars. The data reduction of the CW signals is also significantly simpler. Because the forward-scatter reflection geometry increases the duration of the echoes relative to the back-scatter case, the problem of the underdense ceiling is partially alleviated. We have built a 'short hop' forward-scatter system between Ottawa and London (Ont) for which the transmitter and receiver are separated by about 500 km. With it, we are able to measure unambiguously the directions of arrival of the echoes using a 5-antenna interferometer. Morton and Jones (1982, MN, 198, 737) have shown how the echo direction distribution can be deconvolved to yield the meteor radiant distribution for back-scatter data. We have extended the technique to the forward-scatter case and present some preliminary meteor radiant distribution maps

Mode-matching analysis of a shielded rectangular dielectric-rod waveguide

Rectangular cross-section dielectric waveguides are widely used at millimeter wavelengths. In addition, shielded dielectric resonators having a square cross-section are often used as filter elements, however there is almost no information available on the effect of the shield. Rectangular or square dielectric waveguide is notoriously difficult to analyze, because of the singular behaviour of the fields at the corners. Most published analyses are for materials with a low dielectric constant, and do not include the effects of a shield. This paper describes a numerically efficient mode matching method for the analysis of shielded dielectric rod waveguide, which is applicable to both low and high dielectric constant materials. The effect of the shield on the propagation behaviour is studied. The shield dimensions may be selected such that the shield has a negligible effect, so that results can be compared with free space data. The results are verified by comparison with several sets of published data, and have been confirmed by measurement for a nominal 'e' r of 37.4