Detection of Bursts from FRB 121102 with the Effelsberg 100-m Radio Telescope at 5 GHz and the Role of Scintillation

FRB 121102, the only repeating fast radio burst (FRB) known to date, was discovered at 1.4 GHz and shortly after the discovery of its repeating nature, detected up to 2.4 GHz. Here we present three bursts detected with the 100-m Effelsberg radio telescope at 4.85 GHz. All three bursts exhibited frequency structure on broad and narrow frequency scales. Using an autocorrelation function analysis, we measured a characteristic bandwidth of the small-scale structure of 6.4$\pm$1.6 MHz, which is consistent with the diffractive scintillation bandwidth for this line of sight through the Galactic interstellar medium (ISM) predicted by the NE2001 model. These were the only detections in a campaign totaling 22 hours in 10 observing epochs spanning five months. The observed burst detection rate within this observation was inconsistent with a Poisson process with a constant average occurrence rate; three bursts arrived in the final 0.3 hr of a 2 hr observation on 2016 August 20. We therefore observed a change in the rate of detectable bursts during this observation, and we argue that boosting by diffractive interstellar scintillations may have played a role in the detectability. Understanding whether changes in the detection rate of bursts from FRB 121102 observed at other radio frequencies and epochs are also a product of propagation effects, such as scintillation boosting by the Galactic ISM or plasma lensing in the host galaxy, or an intrinsic property of the burst emission will require further observations.Comment: Accepted to ApJ. Minor typos correcte

A sample of low energy bursts from FRB 121102

We present 41 bursts from the first repeating fast radio burst discovered (FRB 121102). A deep search has allowed us to probe unprecedentedly low burst energies during two consecutive observations (separated by one day) using the Arecibo telescope at 1.4 GHz. The bursts are generally detected in less than a third of the 580-MHz observing bandwidth, demonstrating that narrow-band FRB signals may be more common than previously thought. We show that the bursts are likely faint versions of previously reported multi-component bursts. There is a striking lack of bursts detected below 1.35 GHz and simultaneous VLA observations at 3 GHz did not detect any of the 41 bursts, but did detect one that was not seen with Arecibo, suggesting preferred radio emission frequencies that vary with epoch. A power law approximation of the cumulative distribution of burst energies yields an index $-1.8\pm0.3$ that is much steeper than the previously reported value of $\sim-0.7$. The discrepancy may be evidence for a more complex energy distribution. We place constraints on the possibility that the associated persistent radio source is generated by the emission of many faint bursts ($\sim700$ ms$^{-1}$). We do not see a connection between burst fluence and wait time. The distribution of wait times follows a log-normal distribution centered around $\sim200$ s; however, some bursts have wait times below 1 s and as short as 26 ms, which is consistent with previous reports of a bimodal distribution. We caution against exclusively integrating over the full observing band during FRB searches, because this can lower signal-to-noise.Comment: Accepted version. 16 pages, 7 figures, 1 tabl

GaBoDS: The Garching-Bonn Deep Survey -- II. Confirmation of EIS cluster candidates by weak gravitational lensing

We report the first confirmation of colour-selected galaxy cluster candidates by means of weak gravitational lensing. Significant lensing signals were identified in the course of the shear-selection programme of dark matter haloes in the Garching-Bonn Deep Survey, which currently covers 20 square degrees of deep, high-quality imaging data on the southern sky. The detection was made in a field that was previously covered by the ESO Imaging Survey (EIS) in 1997. A highly significant shear-selected mass-concentration perfectly coincides with the richest EIS cluster candidate at z~0.2, thus confirming its cluster nature. Several other shear patterns in the field can also be identified with cluster candidates, one of which could possibly be part of a filament at z~0.45.Comment: 4 pages, 4 figures, submitted to A&A Letter

Beyond Improved Retention: Building Value-Added Success on a Broad Foundation

Many have documented the positive benefits of Living and Learning Communities (LLCs), but creating an environment that truly integrates living and learning across campus can be a challenge. In this paper we chronicle an LLC program that was intentionally built upon a broad foundation. By including faculty, staff, and student leader representation from across the campus - from admissions and academic affairs to student engagement, residence life, and enrollment management - Cabrini College has created a program that has gone beyond the numerical targets of increased retention and increased academic success. We believe the program has created transformational experiences for many student participants, and that these experiences are the result of the LLC’s integrated design. After providing a history of the program and its unique institutional structure, and offering suggestions for other institutions designing LLCs, we present both quantitative and qualitative measures of success. Richard D. Gebauer is the Director of the First-Year Experience at Cabrini College in Radnor, Pennsylvania. Nancy L. Watterson is an Associate Professor, Social Justice, at Cabrini College. Eric Malm is an Associate Professor of Economics and Business at Cabrini College. Michelle Filling-Brown is an Assistant Professor of English at Cabrini College. John W. Cordes is an Associate Professor in Communication at Cabrini College

Cinco libros, dos prólogos y cuatrocientos sesenta y cinco capítulos para Tirant lo Blanch

Abordo en este artículo las características de la división textual de la versión anónima de la novela de Joanot Martorell que imprimió Diego de Gumiel en 1511, con el objetivo, a mi juicio, de ofrecer a sus lectores una obra que se amoldara al patrón de los libros de caballerías que tanto éxito empezaban a gozar ya a fines de la primera década del siglo XV

Bigger is not always better : viability selection on body mass varies across life stages in a hibernating mammal

ACKNOWLEDGEMENTS: We would like to express our thanks to all the hard-working marmoteers, across the course of the study, that helped to collect the annual field data. In addition, we would like to specifically thank Kenneth B. Armitage for starting the project and access to the long-term body mass data. This work 431 was supported by an EASTBIO PhD studentship from the Biotechnology and Biological Sciences Research Council (BBSRC) and the University of Aberdeen, which was awarded to A.H.M.J. D.T.B was supported by the National Geographic Society, UCLA (Faculty Senate and the Division of Life Sciences), a Rocky Mountain Biological Laboratory research fellowship, and NSF-IDBR-0754247, DEB435 1119660 and 1557130 (to DTB); and NSF-DBI 0242960, 0731346, and 1262713 (to the RMBL).Peer reviewedPublisher PD

Competition of Spin-Fluctuations and Phonons in Superconductivity of ZrZn2

It has been long suspected that spin fluctuations in the weak itinerant ferromagnet ZrZn2 may lead to a triplet superconductivity in this material. Here we point out another possibility, a spatially inhomogeneous singlet superconducting state (a Fulde-Ferrell-Larkin-Ovchinnikov state). We report detailed electronic structure calculations, as well as calculations of the zone center phonons and their coupling with electrons. We find that the exchange splitting is nonuniform and may allow for gap formation at some parts of the Fermi surface. We also find that there is substantial coupling of Zr rattling modes with electrons, which can, in principle, provide the necessary pairing in the s-channel.Comment: 4 pages, embedded color postscript figures. JPEG versions available from the author