12296806
Optical-Infrared ANDICAM Observations of the Transient Associated with GRB 030329
We present photometry of the transient associated with γ-burst (GRB) 030329 obtained with the Cerro Tololo Inter-American Observatory 1.3 meter telescope and the ANDICAM instrument, a dual optical/infrared imager. Without the need for light-curve interpolation to produce snapshot broadband spectra, we show that the transient spectrum remained statistically achromatic from day 2.7 to day 5.6, during a rebrightening episode. Associating the light in these early epochs with the GRB afterglow, we infer a modest level of extinction due to the host galaxy in the line of sight toward the GRB: AV(host) = 0.30 ± 0.03 mag for β = -0.5 and AV(host) < 0.4 mag (3 σ) for any physically plausible value of β (with flux fν ∝ λ-β). We conclude that the spectral slope of the afterglow component was more than β = -0.8 between day 2.7 and 5.6 after the GRB, excluding the possibility that the synchrotron cooling break passed through the optical/IR bandpass over that period. Taking extinction into account, a decomposition of the light curve into an afterglow and supernova component requires the presence of a supernova (SN) similar to that of SN 1998bw, an afterglow that shows some evidence for a second break around day 8–10 and a fifth rebrightening event around day 15. Assuming a, SN 1988bw–like evolution and a contemporaneous GRB and SN event, the peak SN brightness was MV = (-19.8 ± 0.4) - 5 log h65 mag.
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.
5990408
The Science Case for PILOT I: Summary and Overview
PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed 2.5-m optical/infrared telescope to be located at Dome C on the Antarctic plateau. Conditions at Dome C are known to be exceptional for astronomy. The seeing (above ∼30 m height), coherence time, and isoplanatic angle are all twice as good as at typical mid-latitude sites, while the water-vapour column, and the atmosphere and telescope thermal emission are all an order of magnitude better. These conditions enable a unique scientific capability for PILOT, which is addressed in this series of papers. The current paper presents an overview of the optical and instrumentation suite for PILOT and its expected performance, a summary of the key science goals and observational approach for the facility, a discussion of the synergies between the science goals for PILOT and other telescopes, and a discussion of the future of Antarctic astronomy. Paper II and Paper III present details of the science projects divided, respectively, between the distant Universe (i.e. studies of first light, and the assembly and evolution of structure) and the nearby Universe (i.e. studies of Local Group galaxies, the Milky Way, and the Solar System).
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.
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.
16811603
Kinematic distributions and nuclear effects of J/ψ production in 920 GeV fixed-target proton-nucleus collisions
AbstractMeasurements of the kinematic distributions of J/ψ mesons produced in p–C, p–Ti and p–W collisions at 
$\sqrt{s}=41.6~\mathrm{GeV}$ 
in the Feynman-x region −0.34<xF<0.14 and for transverse momentum up to pT=5.4 GeV/c are presented. The xF and pT dependencies of the nuclear suppression parameter, α, are also given. The results are based on 2.4×105J/ψ mesons reconstructed in both the e+e− and μ+μ− decay channels. The data have been collected by the HERA-B experiment at the HERA proton ring of the DESY laboratory. The measurement explores the negative region of xF for the first time. The average value of α in the measured xF region is 0.981±0.015. The data suggest that the strong nuclear suppression of J/ψ production previously observed at high xF turns into an enhancement at negative xF.
1529836
Search for a new gauge boson in π0 decays
Abstract A search was made for a new light gauge boson X which might be produced in π 0 → γ + X decay from neutral pions generated by 450 GeV protons in the CERN SPS neutrino target. The X's would penetrate the downstream shielding and be observed in the NOMAD detector via the Primakoff effect, in the process of X → π 0 conversion in the external Coulomb field of a nucleus. With 1.45×10 18 protons on target, 20 candidate events with energy between 8 and 140 GeV were found from the analysis of neutrino data. This number is in agreement with the expectation of 18.1±2.8 background events from standard neutrino processes. A new 90 % C.L. upper limit on the branching ratio Br ( π 0 → γ + X ) −5 for X masses ranging from 0 to 120 MeV/ c 2 is obtained.
73663027
Gas gain uniformity tests performed on multiwire proportional chambers for the LHCb muon system
We present the experimental setup and the results of the gas gain uniformity tests performed as part of the quality control of the multiwire proportional chambers produced at CERN for the LHCb muon system. The test provides a relative gas gain measurement over the whole chamber sensitive area. It is based on the analysis of the pulse height spectrum obtained when the chamber is exposed to a 241 Am radioactive source. Since the measurement is normalized to the peak of a precise pulse generator, the gain uniformity can also be evaluated among different gas gaps and different chambers. In order to cope with the specific requirements related to the relatively high number of chambers and to their varying geometry, a standalone and compact data acquisition system has been developed which is programmable at the hardware level and may be applied to many other applications requiring precise time-to-digital and analog-to-digital conversion, in correlated or non-correlated mode. r 2008 Elsevier B.V. All rights reserved. PACS: 06.60.Mr; 07.05.Hd; 29.30.Kv; 29.40.Cs
110313521
LHCb online system technical design report: Data acquisition and experiment control
38972186
The trigger system of the NOMAD experiment
The NOMAD trigger system is described in the present paper. It is made up of a large area plastic scintillator veto system, two trigger scintillator planes inside a 0.4 T magnetic field and their associated trigger electronics. Special features of the system consist of the use of proximity mesh photomultipliers which allow the trigger scintillators to operate in the magnetic field, and the use of custom-built VME modules which perform the trigger logic decisions, the signal synchronisation and gate generation, event counting and livetime calculations. This paper also includes a description of each of the NOMAD triggers, with their calculated and measured rates, efficiencies and livetimes.