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The Integration and Verification Testing and characterization of the expected performance of the Large Synoptic Survey Telescope (LSST) Camera is described. The LSST Camera will be the largest astronomical camera ever constructed, featuring a 3.2 Gpixel focal plane mosaic of 189 CCDs. In this paper, we describe the verification testing program developed in parallel with the integration of the Camera, and the results from our performance characterization of the Camera. Our testing program includes electro-optical characterization and CCD height measurements of the focal plane, at several steps during integration, as well as a complete functional and characterization program for the finished focal plane. It also includes a suite of functional tests of the major Camera mechanisms: shutter, filter exchange system and thermal control. Finally, we expect to test the fully assembled Camera prior to its scheduled completion and delivery to the LSST observatory in early calendar 2021.

By the end of 2018, 42 years after the landing of the two Viking seismometers on Mars, InSight will deploy onto Mars’ surface the SEIS (Seismic Experiment for Internal Structure) instrument; a six-axes seismometer equipped with both a long-period three-axes Very Broad Band (VBB) instrument and a three-axes short-period (SP) instrument. These six sensors will cover a broad range of the seismic bandwidth, from 0.01 Hz to 50 Hz, with possible extension to longer periods. Data will be transmitted in the form of three continuous VBB components at 2 sample per second (sps), an estimation of the short period energy content from the SP at 1 sps and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams will be augmented by requested event data with sample rates from 20 to 100 sps. SEIS will improve upon the existing resolution of Viking’s Mars seismic monitoring by a factor of ∼2500 at 1 Hz and ∼200000 at 0.1 Hz. An additional major improvement is that, contrary to Viking, the seismometers will be deployed via a robotic arm directly onto Mars’ surface and will be protected against temperature and wind by highly efficient thermal and wind shielding. Based on existing knowledge of Mars, it is reasonable to infer a moment magnitude detection threshold of Mw∼3 at 40∘ epicentral distance and a potential to detect several tens of quakes and about five impacts per year. In this paper, we first describe the science goals of the experiment and the rationale used to define its requirements. We then provide a detailed description of the hardware, from the sensors to the deployment system and associated performance, including transfer functions of the seismic sensors and temperature sensors. We conclude by describing the experiment ground segment, including data processing services, outreach and education networks and provide a description of the format to be used for future data distribution., Space Science Reviews, 215 (1), ISSN:1572-9672, ISSN:0038-6308

arXiv:1607.06195v1.-- et al., How black holes accrete surrounding matter is a fundamental yet unsolved question in astrophysics. It is generally believed that matter is absorbed into black holes via accretion disks, the state of which depends primarily on the mass-accretion rate. When this rate approaches the critical rate (the Eddington limit), thermal instability is supposed to occur in the inner disk, causing repetitive patterns of large-amplitude X-ray variability (oscillations) on timescales of minutes to hours. In fact, such oscillations have been observed only in sources with a high mass-accretion rate, such as GRS 1915+105 (refs 2, 3). These large-amplitude, relatively slow timescale, phenomena are thought to have physical origins distinct from those of X-ray or optical variations with small amplitudes and fast timescales (less than about 10 seconds) often observed in other black-hole binaries - for example, XTE J1118+480 (ref. 4) and GX 339â '4 (ref. 5). Here we report an extensive multi-colour optical photometric data set of V404 Cygni, an X-ray transient source containing a black hole of nine solar masses (and a companion star) at a distance of 2.4 kiloparsecs (ref. 8). Our data show that optical oscillations on timescales of 100 seconds to 2.5 hours can occur at mass-accretion rates more than ten times lower than previously thought. This suggests that the accretion rate is not the critical parameter for inducing inner-disk instabilities. Instead, we propose that a long orbital period is a key condition for these large-amplitude oscillations, because the outer part of the large disk in binaries with long orbital periods will have surface densities too low to maintain sustained mass accretion to the inner part of the disk. The lack of sustained accretion - not the actual rate - would then be the critical factor causing large-amplitude oscillations in long-period systems., A.S.P., E.D.M. and A.A.V. are grateful to the Russian Science Foundation (grant 15-12- 30016) for support. This work was supported by the Grant-in-Aid “Initiative for High-Dimensional Data-Driven Science through Deepening of Sparse Modeling” from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan (25120007 TK and 26400228 YU).

The Large Synoptic Survey Telescope, under construction in Chile, is an 8.4 m optical survey telescope with a dedicated 3.2 Giga-pixel camera. The design and construction of the camera is spearheaded at SLAC National Accelerator Laboratory and here we present a general overview of the camera integration and test activities. An overview of the methodologies used for the planning and management of this subsystem will be given, along with a high-level summary of the status of the major pieces of I&T hardware. Finally a brief update will be given on the current state of the LSST Camera integration and testing program.

The LSST Camera focal plane comprises twenty-one raft tower modules (RTMs), each with nine CCD sensors and their associated electronics. RTMs are assembled at Brookhaven National Lab and shipped to SLAC National Lab, where they must be re-verified before being assembled into the full focal plane. The process for accepting an RTM at SLAC has been thoroughly documented, including unpacking a raft from its shipping container, verifying aliveness of the electrical connections, performing metrology and electro-optical testing in an environment similar to the full Camera, and finally storing the RTM until it can be installed into the LSST Camera

International audience; The Integration and Verification Testing of the Large Synoptic Survey Telescope (LSST) Camera is described. The LSST Camera will be the largest astronomical camera ever constructed, featuring a 3.2 giga-pixel focal plane mosaic of 189 CCDs with in-vacuum controllers and readout, dedicated guider and wavefront CCDs, a three element corrector with a 1.6-meter diameter initial optic, six optical filters covering wavelengths from 320 to 1000 nm with a novel filter exchange mechanism, and camera-control and data acquisition capable of digitizing each image in two seconds. In this paper, we describe the integration processes under way to assemble the Camera and the associated verification testing program. The Camera assembly proceeds along two parallel paths: one for the focal plane and cryostat and the other for the Camera structure itself. A range of verification tests will be performed interspersed with assembly to verify design requirements with a test-as-you-build methodology. Ultimately, the cryostat will be installed into the Camera structure as the two assembly paths merge, and a suite of final Camera system tests performed. The LSST Camera is scheduled for completion and delivery to the LSST observatory in 2020.

We† provide an overview of the Model Based Systems Engineering (MBSE) language, tool, and methodology being used in our development of the Operational Plan for Large Synoptic Survey Telescope (LSST) operations. LSST’s Systems Engineering (SE) team is using a model-based approach to operational plan development to: 1) capture the topdown stakeholders’ needs and functional allocations defining the scope, required tasks, and personnel needed for operations, and 2) capture the bottom-up operations and maintenance activities required to conduct the LSST survey across its distributed operations sites for the full ten year survey duration. To accomplish these complimentary goals and ensure that they result in self-consistent results, we have developed a holistic approach using the Sparx Enterprise Architect modeling tool and Systems Modeling Language (SysML). This approach utilizes SysML Use Cases, Actors, associated relationships, and Activity Diagrams to document and refine all of the major operations and maintenance activities that will be required to successfully operate the observatory and meet stakeholder expectations. We have developed several customized extensions of the SysML language including the creation of a custom stereotyped Use Case element with unique tagged values, as well as unique association connectors and Actor stereotypes. We demonstrate this customized MBSE methodology enables us to define: 1) the rolls each human Actor must take on to successfully carry out the activities associated with the Use Cases; 2) the skills each Actor must possess; 3) the functional allocation of all required stakeholder activities and Use Cases to organizational entities tasked with carrying them out; and 4) the organization structure required to successfully execute the operational survey. Our approach allows for continual refinement utilizing the systems engineering spiral method to expose finer levels of detail as necessary. For example, the bottom-up, Use Case-driven approach will be deployed in the future to develop the detailed work procedures required to successfully execute each operational activity.

Construction of the Large Synoptic Survey Telescope system involves several different organizations, a situation that poses many challenges at the time of the software integration of the components. To ensure commonality for the purposes of usability, maintainability, and robustness, the LSST software teams have agreed to the following for system software components: a summary state machine, a manner of managing settings, a flexible solution to specify controller/controllee relationships reliably as needed, and a paradigm for responding to and communicating alarms. This paper describes these agreed solutions and the factors that motivated these.

A main science goal for the Large Synoptic Survey Telescope (LSST) is to measure the cosmic shear signal from weak lensing to extreme accuracy. One difficulty, however, is that with the short exposure time ($\simeq$15 seconds) proposed, the spatial variation of the Point Spread Function (PSF) shapes may be dominated by the atmosphere, in addition to optics errors. While optics errors mainly cause the PSF to vary on angular scales similar or larger than a single CCD sensor, the atmosphere generates stochastic structures on a wide range of angular scales. It thus becomes a challenge to infer the multi-scale, complex atmospheric PSF patterns by interpolating the sparsely sampled stars in the field. In this paper we present a new method, PSFent, for interpolating the PSF shape parameters, based on reconstructing underlying shape parameter maps with a multi-scale maximum entropy algorithm. We demonstrate, using images from the LSST Photon Simulator, the performance of our approach relative to a 5th-order polynomial fit (representing the current standard) and a simple boxcar smoothing technique. Quantitatively, PSFent predicts more accurate PSF models in all scenarios and the residual PSF errors are spatially less correlated. This improvement in PSF interpolation leads to a factor of 3.5 lower systematic errors in the shear power spectrum on scales smaller than $\sim13'$, compared to polynomial fitting. We estimate that with PSFent and for stellar densities greater than $\simeq1/{\rm arcmin}^{2}$, the spurious shear correlation from PSF interpolation, after combining a complete 10-year dataset from LSST, is lower than the corresponding statistical uncertainties on the cosmic shear power spectrum, even under a conservative scenario.

The complete 10-year survey from the Large Synoptic Survey Telescope (LSST) will image $\sim$ 20,000 square degrees of sky in six filter bands every few nights, bringing the final survey depth to $r\sim27.5$, with over 4 billion well measured galaxies. To take full advantage of this unprecedented statistical power, the systematic errors associated with weak lensing measurements need to be controlled to a level similar to the statistical errors. This work is the first attempt to quantitatively estimate the absolute level and statistical properties of the systematic errors on weak lensing shear measurements due to the most important physical effects in the LSST system via high fidelity ray-tracing simulations. We identify and isolate the different sources of algorithm-independent, \textit{additive} systematic errors on shear measurements for LSST and predict their impact on the final cosmic shear measurements using conventional weak lensing analysis techniques. We find that the main source of the errors comes from an inability to adequately characterise the atmospheric point spread function (PSF) due to its high frequency spatial variation on angular scales smaller than $\sim10'$ in the single short exposures, which propagates into a spurious shear correlation function at the $10^{-4}$--$10^{-3}$ level on these scales. With the large multi-epoch dataset that will be acquired by LSST, the stochastic errors average out, bringing the final spurious shear correlation function to a level very close to the statistical errors. Our results imply that the cosmological constraints from LSST will not be severely limited by these algorithm-independent, additive systematic effects.

The Taiwanese-American Occultation Survey (TAOS) monitors fields of up to ~1000 stars at 5 Hz simultaneously with four small telescopes to detect occultation events from small (~1 km) Kuiper Belt Objects (KBOs). The survey presents a number of challenges, in particular the fact that the occultation events we are searching for are extremely rare and are typically manifested as slight flux drops for only one or two consecutive time series measurements. We have developed a statistical analysis technique to search the multi-telescope data set for simultaneous flux drops which provides a robust false positive rejection and calculation of event significance. In this paper, we describe in detail this statistical technique and its application to the TAOS data set., 15 pages, 14 figures. Submitted to PASP

We analyzed data accumulated during 2005 and 2006 by the Taiwan-American Occultation Survey (TAOS) in order to detect short-period variable stars (periods of

Using 7 years of MACHO survey data, we present a new determination of the optical depth to microlensing towards the Galactic bulge. We select the sample of 62 microlensing events (60 unique) on clump giant sources and perform a detailed efficiency analysis. We use only the clump giant sources because these are bright bulge stars and are not as strongly affected by blending as other events. Using a subsample of 42 clump events concentrated in just 4.5 square degrees, we find tau = 2.17^{+0.47}_{-0.38} x 10^{-6} at (l,b) = (1.50, -2.68), somewhat smaller than found in most previous MACHO studies, but in excellent agreement with recent theoretical predictions. We also present the optical depth in each of the 19 fields in which we detected events, and find limits on optical depth for fields with no events. The errors in optical depth in individual fields are dominated by Poisson noise. We measure optical depth gradients (1.06 +/- 0.71) x 10^{-6} deg^{-1} and (0.29 +/- 0.43) x 10^{-6} deg^{-1} in the galactic latitude b and longitude l directions, respectively. Finally, we discuss the possibility of anomalous duration distribution of events in the field 104 centered on (l,b) = (3.11, -3.01) as well as investigate spatial clustering of events in all fields., Comment: 42 pages, 15 figures (6 of them in color), 12 tables; results unchanged, discussion of blending strengthened including addition of new appendix; to be published in ApJ, Vol. 630, Sept. 10, 2005 issue

The Northern Sky Variability Survey (NSVS) is a temporal record of the sky over the optical magnitude range from 8 to 15.5. It was conducted in the course of the first generation Robotic Optical Transient Search Experiment (ROTSE-I) using a robotic system of four co-mounted unfiltered telephoto lenses equipped with CCD cameras. The survey was conducted from Los Alamos, NM, and primarily covers the entire northern sky. Some data in southern fields between declinations 0 and -38 deg is also available, although with fewer epochs and noticeably lesser quality. The NSVS contains light curves for approximately 14 million objects. With a one year baseline and typically 100-500 measurements per object, the NSVS is the most extensive record of stellar variability across the bright sky available today. In a median field, bright unsaturated stars attain a point to point photometric scatter of ~0.02 mag and position errors within 2 arcsec. At Galactic latitudes |b| < 20 deg the data quality is limited by severe blending due to ~14 arcsec pixel size. We present basic characteristics of the data set and describe data collection, analysis, and distribution. All NSVS photometric measurements are available for on-line public access from the Sky Database for Objects in Time-Domain (SkyDOT; http://skydot.lanl.gov) at LANL. Copies of the full survey photometry may also be requested on tape., accepted for publication in Astronomical Journal

We describe the efforts of the Taiwan-America Occultation Survey (TAOS) project to develop a data acquisition and analysis scheme for fast CCD imaging photometry. The TAOS project aims to conduct a census of the Kuiper-belt objects (KBOs) by detecting chance stellar occultation events by these small bodies in the outer reach of the solar system. An array of telescopes, each with fast optics (f/2) of 0.5 m aperture and equipped with a 2K CCD camera (3 square degrees FOV), have been set up in central Taiwan to monitor a couple thousand stars simultaneously. By reading out the CCD chip sequentially a few rows of pixels at a time (pause-and-shift), it is possible to achieve stellar photometry with a sampling rate up to several hertz. Here we report how such a setup has been used to observe the SX Phoenicis type variable CY Aqr to illustrate the potential usefulness of the TAOS database in stellar variability studies.

We have frequency analyzed 6391 variables classified earlier as fundamental mode RR Lyrae (RR0) stars in the MACHO database on the Large Magellanic Cloud (LMC). The overwhelming majority of these variables have been proved to be indeed RR0 stars, whereas the remaining ones have fallen in one of the following categories: single- and double-mode Cepheids, binaries, first overtone and double-mode RR Lyrae stars and non-classified variables. Special attention has been paid to the Blazhko stars. We found altogether 731 Blazhko variables showing either a doublet or an equidistant triplet pattern at the main pulsation component in their frequency spectra. The incidence rate of the Blazhko variables among the RR0 stars in the LMC is 11.9%, which is three times higher than their rate among the first overtone RR Lyrae stars. From the frequency spectra we found that variables with larger modulation amplitudes at the higher frequency side of the main pulsation component are three times more frequent than the ones showing the opposite amplitude pattern. A search made for a modulation component with the Blazhko period in the average brightness of the individual variables showed the existence of such a modulation with an overall amplitude of ~0.006 mag. On the other hand, a similar search for quadruple modulation patterns around the main pulsation component have failed to clearly detect such components at the ~0.004 mag level. This means that the amplitudes of the quadruple components should be, on the average, at least ten times smaller than those of the triplet components. This finding and the existence of Blazhko variables with highly asymmetric modulation amplitudes not only question the validity of the magnetic oblique rotator model, but also puts stringent constraints on models based on mode coupling theories., Comment: 14 pages, 15 figures, 6 tables, to appear in ApJ (Vol. 598, November 20, 2003)

We present preliminary results of the analysis of the first 500 square degrees of the Southern Edgeworth-Kuiper belt Survey, a large sky survey which ran from January 2000 to January 2003 and comprises 2900° in total. Early tests predict that we should discover ~10 bright TNOs in our data, doubling the current known population.

The crystal structure of tetrahydrofuran deuterate, a clathrate hydrate, has been refined from neutron powder diffraction data at five temperatures in the range 7−265 K. The thermal expansivity was shown to be greater than that of ice Ih in the same range of temperature (T), as observed in previous studies of other clathrates. The overall effect of T has been resolved into contributions from different geometrical parameters in the structure. Thus, an increase in T results in expansion of the host-lattice framework with increases in both the D−D and O−O distances and out-of-plane tilting of water molecules. The greatest dependence on T is exhibited by the D−D distances and the distortion of the hexagonal faces from planarity, which is particularly pronounced in the range 75−140 K. The cage volumes show a complex dependence on T: from 7 to 140 K, the volume of the small cage decreases slightly and that of the large cage increases, and between 140 and 205 K, the trend is reversed. The most pronounced struct...

The Taiwanese—American Occultation Survey (TAOS) seeks to determine the number and size spectrum for small (~ 3 km) bodies in the Kuiper Belt. This will be accomplished by searching for the brief occultations of bright stars (R ~ 14) by these objects. We have designed and built a special purpose photometric monitoring system for this purpose. TAOS comprises four 50 cm telescopes, each equipped with a 2048 × 2048 pixel CCD camera, in a compact array located in the central highlands of Taiwan. TAOS will monitor up to 3, 000 stars at 5 Hz. The system will go into scientific operation at the end of 2003.

The observation of a prompt optical flash from GRB990123 convincingly demonstrated the value of autonomous robotic telescope systems. Pursuing a program of rapid follow-up observations of gamma-ray bursts, the Robotic Optical Transient Search Experiment (ROTSE) has developed a next-generation instrument, ROTSE-III, that will continue the search for fast optical transients. The entire system was designed as an economical robotic facility to be installed at remote sites throughout the world. There are seven major system components: optics, optical tube assembly, CCD camera, telescope mount, enclosure, environmental sensing & protection and data acquisition. Each is described in turn in the hope that the techniques developed here will be useful in similar contexts elsewhere., 19 pages, including 4 figures. To be published in PASP in January, 2003. PASP Number IP02-110

A single-crystal sapphire cell for performing neutron-scattering experiments on gas hydrates synthesized in situ was designed and fabricated to operate at pressures up to 350 bar (1 bar = 105 Pa) and temperatures between 10 and 300 K. The single-crystal cell is cut off-axis from the c-axis of sapphire to avoid Bragg diffraction in the scattering plane for the Debye–Scherrer geometry. The cell is pressurized from a boosted pumping station via a small-diameter stainless-steel pipe. The cell is cylindrical with no external supports. The design of the cell allows the unobstructed detection of neutrons scattered from the sample. This requirement necessitated a departure from the predominant style of sapphire cells reported in the literature. Several iterations of design modifications and finite-element modeling were performed prior to building the prototype. The cell was tested hydrostatically at room temperature. Preliminary inelastic neutron scattering data are reported to verify the performance of the cell. PACS No.: 61.12ex

The Large Synoptic Survey Telescope project was an early adopter of SysML and Model Based Systems Engineering practices. The LSST project began using MBSE for requirements engineering beginning in 2006 shortly after the initial release of the first SysML standard. Out of this early work the LSST’s MBSE effort has grown to include system requirements, operational use cases, physical system definition, interfaces, and system states along with behavior sequences and activities. In this paper we describe our approach and methodology for cross-linking these system elements over the three classical systems engineering domains – requirement, functional and physical - into the LSST System Architecture model. We also show how this model is used as the central element to the overall project systems engineering effort. More recently we have begun to use the cross-linked modeled system architecture to develop and plan the system verification and test process. In presenting this work we also describe “lessons learned” from several missteps the project has had with MBSE. Lastly, we conclude by summarizing the overall status of the LSST’s System Architecture model and our plans for the future as the LSST heads toward construction.

We present the preliminary results of our astrometric study of stellar motions along the lines of sight of the Magellanic Clouds and the Galactic bulge. Using 5 years of MACHO project point-spread function photometry, we find that we can easily select stars with proper motions of 003 yr-1 from these very dense fields, using the characteristic shapes of their light curves. By performing astrometry on photometrically selected, candidate, high proper motion (HPM) stars in 50 deg2, we have discovered 154 new HPM stars from ~55 million stars monitored by the MACHO project. These new objects have proper motions as high as 05 yr-1, brightnesses ranging from V ~ 13 to V ~ 19, and V-R colors between 0.3 and 1.45.

The X-ray nova XTE J1118+480 exhibited two outbursts in the early part of 2000. As detected by the Rossi X-Ray Timing Explorer (RXTE), the first outburst began in early January and the second began in early March. Routine imaging of the northern sky by the Robotic Optical Transient Search Experiment (ROTSE) shows the optical counterpart to XTE J1118+480 during both outbursts. These data include over 60 epochs from January to June 2000. A search of the ROTSE data archives reveal no previous optical outbursts of this source in selected data between 1998 April and 2000 January. While the X-ray-to-optical flux ratio of XTE J1118+480 was low during both outbursts, we suggest that they were full X-ray novae and not minioutbursts based on comparison with similar sources. The ROTSE measurements taken during the 2000 March outburst also indicate a rapid rise in the optical flux that preceded the X-ray emission measured by the RXTE by approximately 10 days. Using these results, we estimate a preoutburst accretion disk inner truncation radius of ~1.2 × 104 Schwarzschild radii.

We report on a search for long duration microlensing events towards the Large Magellanic Cloud. We find none, and therefore put limits on the contribution of high mass objects to the Galactic dark matter. At 95% confidence level we exclude objects in the mass range 0.3 solar masses to 30.0 solar masses from contributing more than 4 times 10^11 solar masses to the Galactic halo. Combined with earlier results, this means that objects with masses under 30 solar masses cannot make up the entire dark matter halo if the halo is of typical size. For a typical dark halo, objects with masses under 10 solar masses contribute less than 40% of the dark matter.

We present a ~ 5-yr optical light curve of the recurrent Be/X-ray transient A0538-66 obtained as a by-product of the MACHO Project. These data reveal both a long-term modulation at P = 420.8 +/- 0.8 d and a short-term modulation at 16.6510 +/- 0.0022 d which, within errors, confirms the previously found orbital period. Furthermore, the orbital activity is only seen at certain phases of the 421 d cycle suggesting that the long-term modulation is related to variations in the Be star envelope., 4 pages, 7 figures, accepted for publication in MNRAS

More than 1300 variables classified provisionally as first overtone RR Lyrae pulsators in the MACHO variable star database of the Large Magellanic Cloud (LMC) have been subjected to standard frequency analysis. Based on the remnant power in the prewhitened spectra, we found 70% of the total population to be monoperiodic. The remaining 30% (411 stars) are classified as one of 9 types according to their frequency spectra. Several types of RR Lyrae pulsational behavior are clearly identified here for the first time. Together with the earlier discovered double-mode (fundamental & first overtone) variables this study increased the number of the known double-mode stars in the LMC to 181. During the total 6.5yr time span of the data, 10% of the stars show strong period changes. We also discovered two additional types of multifrequency pulsators with low occurrence rates of 2% for each. In the first type there remains one closely spaced component after prewhitening by the main pulsation frequency. In the second type the number of remnant components is two, they are also closely spaced, and, in addition, they are symmetric in their frequency spacing relative to the central component. This latter type of variables is associated with their relatives among the fundamental pulsators, known as Blazhko variables. Their high frequency (~20%) among the fundamental mode variables versus the low occurrence rate of their first overtone counterparts makes it more difficult to explain Blazhko phenomenon by any theory depending mainly on the role of aspect angle or magnetic field. Current theoretical models invoke nonradial pulsation components in these stars.

In order to observe nearly simultaneous emission from gamma-ray bursts (GRBs), the Robotic Optical Transient Search Experiment (ROTSE) receives triggers via the GRB Coordinates Network (GCN). Since beginning operations in 1998 March, ROTSE has also taken useful data for 10 SGR events: eight from SGR 1900+14 and two from SGR 1806-20. We have searched for new or variable sources in the error regions of these SGRs, and no optical counterparts were observed. Limits are in the range mROTSE ≈ 12.5-15.5 during the period 20 s to 1 hr after the observed SGR events.

Using the exceptional long-term monitoring capabilities of the MACHO project, we present here the optical history of LMC X-2 for a continuous 6-yr period. These data were used to investigate the previously claimed periodicities for this source of 8.15 h and 12.54 d : we find upper amplitude limits of 0.10 mag and 0.09 mag, respectively., 4 pages, 4 figures. Minor changes, including title. MNRAS, in press

We present the first results of the analysis of 22 Blazhko stars. We find: 1) Blazhko RRab stars that are nearly pure amplitude modulators; 2) Blazhko RRab stars that have both amplitude and phase modulation; 3) A Blazhko RRab star that has an abrupt period change; 4) Proof of the Blazhko effect in RRc stars. Our data show the character of the amplitude and phase modulations of the light curves over the Blazhko cycles far better than has been previously possible.

The MACHO data base has been used to examine light curves of all red giant stars brighter than Mbol ∼ −2 in a 0.5° × 0.5° area of the LMC bar. Periods, often multiple, have been searched for in all stars found to be variable. Five distinct period-luminosity sequences have been found on the low mass (M ≲ 2.25M⊙) giant branch. Comparison of observed periods, luminosities and period ratios with theoretical models identifies Miras unambiguously as radial fundamental mode pulsators, while semi-regular variables can be pulsating in the 1st, 2nd or 3rd overtone, or even the fundamental. All these variables lie on just 3 of the 5 distinct sequences, and they all appear to be on the AGB.The fourth sequence contains red giants on the first giant branch (FGB) or at the red end of the core-helium burning loops of intermediate mass stars (M ≳ 2.25M⊙). The light curves of these stars strongly suggest that they are contact binaries, and they make up ∼0.5% of stars within 1 mag. of the FGB tip. Stars on the fifth sequence show semi-regular, eclipse-like light curves. The light curves and periods of these stars suggest that they are in semi-detached binaries, transfering mass to an invisible companion via a stellar wind or Roche lobe overflow. They make up ∼25% of AGB stars. If the existence of these red giant contact and semi-detached binaries is confirmed, then extant theories of binary star evolution will require substantial modification.

Forms of the Poisson summation formula (PSF) appropriate for the summation of semi-infinite and infinite Fourier series are derived. Application of these results to the acceleration of convergence of various types of series with monotonically decreasing coefficient functions yields transformed series with terms that decay either exponentially or with the inverse first or second power of the index variable. These two very different convergence properties are explained in terms of the asymptotic properties of the relevant Fourier transforms, which are in turn related to the power series expansions of the summand functions in the original Fourier series. The result is that the Poisson summation formula works best for Fourier cosine series in which the summand functions are expansible in even powers, and for Fourier sine series in which the summand functions have power series with odd powers. Here, application of the PSF produces series of terms that decay exponentially with increasing argument x. In contrast, application of the semi-infinite version of the PSF to Fourier cosine series of terms with odd-power expansions, or to Fourier sine series of terms with even-power expansions yields transformed series involving functions of the form , which decay approximately as . If the summand function in the Fourier series has a power series with both even and odd powers, the transformed series involves sine and cosine integral functions, which decay approximately as . Fourier series of these last three types in general require additional acceleration, for example, by application of the Kummer transformation.

Apical and basal membrane fractions from Locusta Malpighian tubules were prepared and were characterized by marker enzyme analysis. The apical membranes contained an azide- and orthovanadate-insensitive ATPase activity that was inhibited by bafilomycin A1 (IC50 = 0.44 nM) and NEM (IC50 = 2.15 microM), and thus was characterized as putative V-type ATPase. The enzyme was stimulated by a variety of monovalent cations (Tris > K = Na > choline > Li = Rb) maximal stimulation occurring at 30-40 mM. It was also stimulated by a variety of monovalent anions (maximal activation 30-40 mM), but was strongly inhibited by nitrate and thiocyanate. SDS-PAGE separation of proteins present in the various membrane fractions was carried out. The apical membrane fraction alone contained a 28 kDa protein band that bound a monoclonal antibody specific for a 28 kDa peptide which was a component of the V-type ATPase from midgut of Manduca sexta and, in native gels, possessed ATPase activity which was also sensitive to both bafilomycin and NEM but not to azide or orthovanadate. Binding of the fluorescent monoclonal antibody was located at the apical boundary of the tubule cells. It was concluded that a V-type ATPase is present at the apical surface of Locusta Malpighian tubule cells and that it is involved in their secretory functioning.

Mean colors and magnitudes of RR Lyrae stars in 24 fields toward the Galactic bulge from the MACHO database are presented. Accurate mean reddenings are computed for these fields on the basis of the mean colors. The distribution along the line of sight of the RR Lyrae population is examined on the basis of the mean magnitudes, and it is shown that the bulk of the RR Lyrae population is not barred. Only the RR Lyrae stars in the inner fields closer to the Galactic center (l{lt}4{degree}, b{gt}{minus}4{degree}) show evidence for a bar. The red giant clump stars in the MACHO fields, however, clearly show a barred distribution, confirming the results of previous studies. Given the different spatial distribution, the RR Lyrae stars and the clump giants trace two different populations. The RR Lyrae variables would represent the inner extension of the Galactic halo in these fields. {copyright} {ital 1998} {ital The American Astronomical Society}

The recent suggestion that the microlensing events observed towards the Large Magellanic Cloud are due to an intervening Sgr-like dwarf galaxy is examined. A search for foreground RR Lyrae in the MACHO photometry database yields 20 stars whose distance distribution follow the expected halo density profile. Cepheid and red giant branch clump stars in the MACHO database are consistent with membership in the LMC. There is also no evidence in the literature for a distinct kinematic population, for intervening gas, or for the turn-off of such a hypothetical galaxy. We conclude that if the lenses are in a foreground galaxy, it must be a particularly dark galaxy.

The MACHO Project is a search for dark matter in the form of massive compact halo objects (Machos). Photometric monitoring of millions of stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and Galactic bulge is used to search for gravitational microlensing events caused by these otherwise invisible objects. Analysis of the first 2.1 years of photometry of 8.5 million stars in the LMC reveals 8 candidate microlensing events. This is substantially more than the number expected ($\sim 1.1$) from lensing by known stellar populations. The timescales ($\that$) of the events range from 34 to 145 days. We estimate the total microlensing optical depth towards the LMC from events with $2 < \that < 200$ days to be $\tau_2^{200} = 2.9 ^{+1.4}_{-0.9} \ten{-7}$ based upon our 8 event sample. This exceeds the optical depth, $\tau_{\rm backgnd} = 0.5 \ten{-7}$, expected from known stars, and the difference is to be compared with the optical depth predicted for a ``standard" halo composed entirely of Machos: $\tau_{halo} = 4.7\ten{-7}$. Likelihood analysis gives a fairly model independent estimate of the halo mass in Machos within 50 kpc of $2.0^{+1.2}_{-0.7} \ten{11} \msun$, about half of the ``standard halo" value. We also find a most probable Macho mass of $0.5^{+0.3}_{-0.2}\msun$, although this value is strongly model dependent. Additionally, the absence of short duration events places stringent upper limits on the contribution of low-mass Machos: objects from $10^{-4} \msun$ to $0.03 \msun$ contribute $\simlt 20\%$ of the ``standard" dark halo.

Two glasshouse pot bioassays were conducted in Perth, Western Australia, in 1994 which compared the seedling resistance of subterranean clover (Trifolium subterraneum L.) with New Zealand white clover (Trifolium repens L.) cultivars ‘Grasslands Huia’, ‘Grasslands Tahora’, ‘Prop’, ‘Grasslands Pitau’ and ‘Grasslands Kopu’ to redlegged earth mite (Halotydeus destructor) (Acarina: Penthaleidae). Plant wet weights, mite development and survival and plant damage scores were monitored. Subterranean clover was more resistant to redlegged earth mite than white clover in both experiments. The white clover cultivars, ‘Grasslands Pitau’ and ‘Grasslands Kopu’ had lower cotyledon damage scores and higher yields than the other white clover cultivars.

Earthworms (Lumbricidae) are an important component in soils in many regions of New Zealand. Four 2.5 ha farmlets based on endophyteinfected and endophyte-free ryegrass were established in March 1993 with or without white clover (Trifolium repens). The abundance of two earthworm species, Aporrectodea caliginosa and Lumbricus rubellus, was monitored mid-season from July 1993 to July 1995 on a trial comparing the effects of ryegrass endophyte (Neotyphodium lolii) on cow health and milksolids production. Earthworms were sampled over two years by immersing soil divots in 4% formalin solution and counting emergence from the soil. A. caliginosa was about two times more abundant than L. rubellus. There were no consistent relationships between earthworm abundance and the presence of endophyte in ryegrass, or with the clover content of the pastures.

We report the discovery of 73 double-mode RR Lyrae (RRd) stars in fields near the bar of the LMC. The stars are detected among the MACHO database of short-period variables that currently contains about 7900 RR Lyrae stars. Fundamental periods (P_0) for these stars are found in the range 0.46-0.55 days and first overtone-to-fundamental period ratios are found to be in the range 0.742 < P_1/P_0 < 0.748. A significant fraction of our current sample have period ratios smaller than any previously discovered RRd variables. We present mean magnitudes, colors, and lightcurve properties for all LMC RRd stars detected to date. The range in period ratios is unexpectedly large. We present a determination of absolute magnitudes for these stars based primarily on pulsation theory and the assumption that all observed stars are at the fundamental blue edge (FBE) of the instability strip. Comparison of the calibrated MACHO V and R_KC photometry with these derived absolute magnitudes yields an absorption-corrected distance modulus to the LMC of 18.57 +/- 0.19 mag which is in good agreement with that found (18.5) through comparison of galactic and LMC Cepheids. Adopting this luminosity calibration, we derive an increase in the distance modulus, and thus a reduction in the age found via isochrone fitting for M15 of about 33% and discuss the implications for cosmology.

We report the discovery of 30 type a,b RR Lyrae (RRab) which are likely members of the Sagittarius (Sgr) dwarf galaxy. Accurate positions, periods, amplitudes and magnitudes are presented. Their distances are determined with respect to RRab in the Galactic bulge found also in the MACHO 1993 data. For R$_{\odot} = 8$ kpc, the mean distance to these stars is $D = 22 \pm 1$ kpc, smaller than previous determinations for this galaxy. This indicates that Sgr has an elongated main body extending for more than 10 kpc, which is inclined along the line of sight, with its northern part (in Galactic coordinates) closer to us. The size and shape of Sgr give clues about the past history of this galaxy. If the shape of Sgr follows the direction of its orbit, the observed spatial orientation suggests that Sgr is moving away from the Galactic plane. Also, Sgr stars may be the sources of some of the microlensing events seen towards the bulge.

The Taiwanese-American Occultation Survey (TAOS) aims to detect serendipitous occultations of stars by small (about 1 km diameter) objects in the Kuiper Belt and beyond. Such events are very rare (, 11 pages, 9 figures. Submitted to Astronomical Journal 2013 January 16

The MACHO collaboration has recently analyzed 2.1 years of photometric data for about 8.5 million stars in the Large Magellanic Cloud (LMC). This analysis has revealed 8 candidate microlensing events and a total microlensing optical depth of $\tau_{meas} = 2.9 +1.4/-0.9 \times 10^{-7}$. This significantly exceeds the number of events (1.1) and the microlensing optical depth predicted from known stellar populations: $\tau_{back} = 5.4\times 10^{-8}$, but it is consistent with models in which about half of the standard dark halo mass is composed of Machos of mass $\sim 0.5 \msun$. One of these 8 events appears to be a binary lensing event with a caustic crossing that is partially resolved which allows us to estimate the distance to the lenses. If the source star is not a short period binary star, then we show that the lens system is very likely to reside in the LMC. However, if we assume that the optical depth for LMC-LMC lensing is large enough to account for our entire lensing signal, then the binary event does not appear to be consistent with lensing of a single LMC source star by a binary residing in the LMC. Thus, while the binary lens may indeed reside in the LMC, there is no indication that most of the lenses reside in the LMC., Comment: 5 pages, 3 postscript figures included; To appear in the Proceedings of the Dark Matter '96 Conference held in Santa Monica, CA, Feb., 1996

The MACHO project has been monitoring about ten million stars in the Large Magellanic Cloud in the search for gravitational microlensing events caused by massive compact halo objects (Machos) in the halo of the Milky Way. The standard analysis for well sampled, long duration microlensing is sensitive to objects with masses 10 −5 ≲ m ≲ 1M ⊙ . However, a different analysis method sensitive to short duration events extends the sensitivity of the experiment to lower masses. Combining the results of the analyses of the first two years of data from the LMC shows that Machos with masses in the range 2.5 × 10 −7 m −2 M ⊙ cannot make up the entire mass of a standard spherical dark halo

The MACHO collaboration is carrying out an extensive survey to detect gravitational microlensing. We have recently demonstrated the ability to detect candidate microlensing events in real time, often well before the peak amplification of the event. This has made possible the acquisition of spectra over the course of an event, the invariance of which has lent strong support to the microlensing interpretation. This paper reports on photometric data that were acquired from two sites, Cerro Tololo Inter-American Observatory and Mount Stromlo, in response to the real time detection of a microlensing event. The superior photometry obtained from Chile and the complementary time coverage demonstrate the viability of mounting an aggressive campaign of microlensing follow-up observations.

Gravitational microlensing is the most straightforward interpretation of the stellar brightenings that have been observed by our team and other experiments. These data have provided some of the most stringent limits to date on the nature of the Galaxy's dark matter halo. The number of events seen towards the LMC indicate that our Galaxy is not surrounded by a “standard” halo of MACHOs in the mass range of 10–6 to 0.3 solar masses. The observed optical depth towards the Galactic Center is an important constraint on the distribution of mass in the plane of the Galaxy.

This white paper describes the LSST Dark Energy Science Collaboration (DESC), whose goal is the study of dark energy and related topics in fundamental physics with data from the Large Synoptic Survey Telescope (LSST). It provides an overview of dark energy science and describes the current and anticipated state of the field. It makes the case for the DESC by laying out a robust analytical framework for dark energy science that has been defined by its members and the comprehensive three-year work plan they have developed for implementing that framework. The analysis working groups cover five key probes of dark energy: weak lensing, large scale structure, galaxy clusters, Type Ia supernovae, and strong lensing. The computing working groups span cosmological simulations, galaxy catalogs, photon simulations and a systematic software and computational framework for LSST dark energy data analysis. The technical working groups make the connection between dark energy science and the LSST system. The working groups have close linkages, especially through the use of the photon simulations to study the impact of instrument design and survey strategy on analysis methodology and cosmological parameter estimation. The white paper describes several high priority tasks identified by each of the 16 working groups. Over the next three years these tasks will help prepare for LSST analysis, make synergistic connections with ongoing cosmological surveys and provide the dark energy community with state of the art analysis tools. Members of the community are invited to join the LSST DESC, according to the membership policies described in the white paper. Applications to sign up for associate membership may be made by submitting the Web form at http://www.slac.stanford.edu/exp/lsst/desc/signup.html with a short statement of the work they wish to pursue that is relevant to the LSST DESC.

We present the study on GRB 071112C X-ray and optical light curves. In these two wavelength ranges, we have found different temporal properties. The R-band light curve showed an initial rise followed by a single power-law decay, while the X-ray light curve was described by a single power-law decay plus a flare-like feature. Our analysis shows that the observed temporal evolution cannot be described by the external shock model in which the X-ray and optical emission are produced by the same emission mechanism. No significant color changes in multi-band light curves and a reasonable value of the initial Lorentz factor ({\Gamma}0 = 275 \pm 20) in a uniform ISM support the afterglow onset scenario as the correct interpretation for the early R-band rise. The result suggests the optical flux is dominated by afterglow. Our further investigations show that the X-ray flux could be created by an additional feature related to energy injection and X-ray afterglow. Different theoretical interpretations indicate the additional feature in X-ray can be explained by either late internal dissipation or local inverse-Compton scattering in the external shock., Comment: 20 pages, 3 figures, accepted for publication in ApJ

Intracellular distributions of Na, K, Mg, Ca, Cl, P, and S were determined in type 1 Malpighian tubule cells of Locusta using X-ray microanalysis. K showed a gradient of increasing concentration from basal to apical surfaces. No other element showed this distribution. Na was below the detection limit. Three types of dark body were present in cytoplasm; one rich in Ca and P and two rich in K and P. Incubation in Rb-Ringer solution resulted in a dramatic fall in cellular K that was not completely replaced by Rb. The distribution of Rb mimicked that of K. Na levels were significantly increased, but the total intracellular monovalent metal concentration was less than in controls. Other elements were little affected. Rb replaced K in dark bodies. Tubules continued to secrete K-rich urine in Rb-Ringer solution even though intracellular [K] was low. Little Rb+ was secreted and Na+ secretion was unchanged. The possible role of dark bodies as a source of secreted K+ is discussed.