55447173
Locations of Peculiar Supernovae as a Diagnostic of Their Origins
We put constraints on the properties of the progenitors of peculiar calcium-rich transients using the distribution of locations within their host galaxies. We confirm that this class of transients do not follow the galaxy stellar mass profile and are more likely to be found in remote locations of their apparent hosts. We test the hypothesis that these transients are from low metallicity progenitors by comparing their spatial distributions with the predictions of self-consistent cosmological simulations that include star formation and chemical enrichment. We find that while metal-poor stars and our transient sample show a consistent preference for large offsets, metallicity alone cannot explain the extreme cases. Invoking a lower age limit on the progenitor helps to improve the match, indicating these events may result from a very old metal-poor population. We also investigate the radial distribution of globular cluster systems, and show that they too are consistent with the class of calcium-rich transients. Because photometric upper limits exist for globular clusters for some members of the class, a production mechanism related to the dense environment of globular clusters is not favoured for the calcium-rich events. However the methods developed in this paper may be used in the future to constrain the effects of low metallicity on radially distant core-collapse events or help establish a correlation with globular clusters for other classes of peculiar explosions.
3943345
First Searches for Optical Counterparts to Gravitational-wave Candidate Events
During the Laser Interferometer Gravitational-wave Observatory and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated optical transient. Images were obtained for eight such GW candidates. We present the methods used to analyze the image data as well as the transient search results. No optical transient was identified with a convincing association with any of these candidates, and none of the GW triggers showed strong evidence for being astrophysical in nature. We compare the sensitivities of these observations to several model light curves from possible sources of interest, and discuss prospects for future joint GW-optical observations of this type.
118556930
HATS-1b: The First Transiting Planet Discovered by the HATSouth Survey
We report the discovery of HATS-1b, a transiting extrasolar planet orbiting the moderately bright V = 12.05 G dwarf star GSC 6652-00186, and the first planet discovered by HATSouth, a global network of autonomous wide-field telescopes. HATS-1b has a period of P 3.4465 days, mass of Mp 1.86 M J, and radius of Rp 1.30 R J. The host star has a mass of 0.99 M ☉ and radius of 1.04 R ☉. The discovery light curve of HATS-1b has near-continuous coverage over several multi-day timespans, demonstrating the power of using a global network of telescopes to discover transiting planets.
113407190
A THEORETICAL COLOR-VELOCITY CORRELATION FOR SUPERNOVAE ASSOCIATED WITH GAMMA-RAY BURSTS
We carry out the first multi-dimensional radiative transfer calculations to simultaneously compute synthetic spectra and light curves for models of supernovae driven by fast bipolar outflows. These allow us to make self-consistent predictions for the orientation dependence of both color evolution and spectral features. We compare models with different degrees of asphericity and metallicity and find significant observable consequences of both. In aspherical models, we find spectral and light curve features that vary systematically with observer orientation. In particular, we find that the early-phase light curves are brighter and bluer when viewed close to the polar axis but that the peak flux is highest for equatorial (off-axis) inclinations. Spectral line features also depend systematically on observer orientation, including the velocity of the Si II 6355 A line. Consequently, our models predict a correlation between line velocity and color that could assist the identification of supernovae associated with off-axis jet-driven explosions. The amplitude and range of this correlation depends on the degree of asphericity, the metallicity, and the epoch of observation but we find that it is always present and acts in the same direction.
13255925
The Mount Stromlo A bell Cluster Supernova Search
We have initiated a 3 year project to find supernovae in a well-defined sample of high-density southern Abell clusters with redshifts z ≤ 0.08. These observations will provide a volume-limited sample of Type Ia supernovae (SNe Ia) to more than a magnitude below their peak brightness and will enable us to (1) measure the luminosity function of SNe, (2) further explore the correlation of light-curve shape with the absolute luminosity of SNe Ia to better understand SNe Ia as distance indicators, (3) measure SN rates, (4) measure the bulk motion of the Local Group using SNe Ia, and (5) directly compare SN Ia distances with brightest cluster galaxy distances. We use the MACHO wide-field two-color imager on the 1.3 m telescope at Mount Stromlo to routinely monitor ~12 clusters per week. We describe our technique for target selection and scheduling search observations, and for finding and identifying SN candidates. We also describe the results from the first year of our program, including the detection of 19 SNe, several RR Lyrae variables, and hundreds of asteroids.
118629327
Supernova 2012ec: Identification of the progenitor and early monitoring with PESSTO
Research by JRM is supported through a Royal Society Research 
Fellowship. SJS is supported by FP7/2007-2013/ERC Grant agreement no. [291222]. GP acknowledges support from the Millennium 
Center for Supernova Science through grant P10-064-F funded by 
‘Programa Bicentenario de Ciencia y Tecnolog´ia de CONICYT’, 
‘Programa Iniciativa Cient´ifica Milenio deMIDEPLAN’ and 
proyecto interno UNAB DI-303-13/R. Research by AGY and his 
group is supported by funding from the FP7/ERC, Minerva and 
GIF grants.
55012937
Recommendations for building and testing the next generation of gaseous detectors
Abstract This paper is the write-up of the very last talk of an interesting, exciting and exhausting workshop. It is not meant as yet another summary talk, but as the very personal view of the situation and recommendations for the future work. It attempts to give a few general hints and rules for the design, construction, development and operation of high rate gaseous detectors.
122986581
Experimental determination of ionization cluster size distributions in counting gases
The distribution of the number of electrons contained in the ionization clusters formed along the track of minimum ionizing particles has been determined experimentally. Results are presented for argon, helium, methane, ethane, propane, isobutane and carbon dioxide, i.e., for gases which are commonly used as counting gases in drift chambers. The probabilities w(n) for the formation of a cluster containing n electrons were found to be monotonically decreasing for increasing n. Typical values for w(1) are 0.66 (Ar), 0.77 (He), and 0.79 (CH4). The results are compared with model predictions.
17409672
Numerical Studies on the Electro-Optic Sampling of Relativistic Electron Bunches
Ultraviolet and X ray free electron lasers require sub-picosecond electron bunches of high charge density. Electro-optic sampling (EOS) is a suitable diagnostic tool for resolving the time structure of these ultrashort bunches. The transient electric field of the relativistic bunch induces a polarization anisotropy in a nonlinear crystal which is sampled by femtosecond laser pulses. In this paper, the EOS process is studied in detailed numerical calculations. The THz and the laser pulses are treated as wave packets which are propagated through the zinc telluride resp. gallium phosphide crystals. The effects of signal broadening and distortion are taken into account. The time resolution is severely limited by transverse optical (TO) lattice oscillations (5.3 THz in ZnTe, 11 THz in GaP). The shortest bunch length which can be resolved with moderate distortion is about 200 fs (FWHM) in ZnTe and 100 fs in GaP.
1728923
Performance of the LHCb muon system
The performance of the LHCb Muon system and its stability across the full 2010 data taking with LHC running at root s = 7 TeV energy is studied. The optimization of the detector setting and the time calibration performed with the first collisions delivered by LHC is described. Particle rates, measured for the wide range of luminosities and beam operation conditions experienced during the run, are compared with the values expected from simulation. The space and time alignment of the detectors, chamber efficiency, time resolution and cluster size are evaluated. The detector performance is found to be as expected from specifications or better. Notably the overall efficiency is well above the design requirements.
122048635
Time resolution limits of the MWPCs for the LHCb muon system
Abstract Detailed simulations of the timing properties of the Multi-Wire-Proportional-Chambers of the LHCb muon system are compared with actual measurements. The simulated time resolution is in good agreement with the measurement which allows to study the resolution limiting parameters like diffusion, charge deposit fluctuations, cluster position fluctuations, electronics noise, track position and wire spacing to show how they affect the performance of the system. Methods to improve the time resolution of the muon chambers are discussed.