ALBERT

Description: The Taurus Molecular Cloud (TMC) is the nearest large star-forming region, prototypical for the distributed mode of low-mass star formation. Pre-main sequence stars are luminous X-ray sources, probably mostly owing to magnetic energy release. Aims. The XMM-Newton Extended Survey of the Taurus Molecular Cloud (EST) presented in this paper surveys the most populated =5 square degrees of the TMC, using the XMM-Newton X-ray observatory to study the thermal structure, variability, and long-term evolution of hot plasma, to investigate the magnetic dynamo, and to search for new potential members of the association. Many targets are also studied in the optical, and high-resolution X-ray grating spectroscopy has been obtained for selected bright sources. Methods. The X-ray spectra have been coherently analyzed with two different thermal models (2-component thermal model, and a continuous emission measure distribution model). We present overall correlations with fundamental stellar parameters that were derived from the previous literature. A few detections from Chandra observations have been added. Results. The present overview paper introduces the project and provides the basic results from the X-ray analysis of all sources detected in the XEST survey. Comprehensive tables summarize the stellar properties of all targets surveyed. The survey goes deeper than previous X-ray surveys of Taurus by about an order of magnitude and for the first time systematically accesses very faint and strongly absorbed TMC objects. We find a detection rate of 85% and 98% for classical and weak-line T Tau stars (CTTS resp. WTTS), and identify about half of the surveyed protostars and brown dwarfs. Overall, 136 out of 169 surveyed stellar systems are detected. We describe an X-ray luminosity vs. mass correlation, discuss the distribution of X-ray-to-bolometric luminosity ratios, and show evidence for lower X-ray luminosities in CTTS compared to WTTS. Detailed analysis (e.g., variability, rotation-activity relations, influence of accretion on X-rays) will be discussed in a series of accompanying papers.

Description: The Hinode satellite (formerly Solar-B) of the Japan Aerospace Exploration Agency's Institute of Space and Astronautical Science (ISAS/JAXA) was successfully launched in September 2006. As the successor to the Yohkoh mission, it aims to understand how magnetic energy is transferred from the photosphere to the upper atmospheres and resulting in explosive energy releases. Hinode is an observatory style mission, with all the instruments being designed and built to work together to address the science aims. There are three instruments onboard: the Solar Optical Telescope (SOT), the EUV Imaging Spectrometer (EIS), and the X-ray Telescope (XRT). This paper overviews the mission, including the satellite, the scientific payload and operations. It will conclude with discussions on how the international science community can participate in the analysis of the mission data.

Description: The dust sublimation zone (DSZ) is the region of pre-main sequence (PMS) disks where dust grains most easily anneal, sublime, and condense out of the gas. Because of this, it is a location where crystalline material may be enhanced and redistributed throughout the rest of the disk. A decade-long program to monitor the thermal emission of the grains located in this region demonstrates that large changes in emitted flux occur in many systems. Changes in the thermal emission between 3 and 13.5 microns were observed in HD 31648 (MWC 480), HD 163296 (MWC 275), and DG Tau. This emission is consistent with it being produced at the DSZ, where the transition from a disk of gas to one of gas+dust occurs. In the case of DG Tau, the outbursts were accompanied by increased emission on the 10 micron silicate band on one occasion, while on another occasion it went into absorption. This requires lofting of the material above the disk into the line of sight. Such changes will affect the determination of the inner disk structure obtained through interferometry measurements, and this has been confirmed in the case of HD 163296. Cyclic variations in the heating of the DSZ will lead to the annealing of large grains, the sublimation of smaller grains, possibly followed by re-condensation as the zone enters a cooling phase. Lofting of dust above the disk plane, and outward acceleration by stellar winds and radiation pressure, can re-distribute the processed material to cooler regions of the disk, where cometesimals form. This processing is consistent with the detection of the preferential concentration of large crystalline grains in the inner few AU of PMS disks using interferometric spectroscopy with the VLTI.

Description: Precision astrometry at microarcsecond accuracy has application to a wide range of astrophysical problems. This paper is a study of the science questions that can be addressed using an instrument with flexible scheduling that delivers parallaxes at about 4 microarcsec (microns)as) on targets as faint as V = 20, and differential accuracy of 0.6 (microns)as on bright targets. The science topics are drawn primarily from the Team Key Projects, selected in 2000, for the Space Interferometry Mission PlanetQuest (SIM PlanetQuest). We use the capabilities of this mission to illustrate the importance of the next level of astrometric precision in modern astrophysics. SIM PlanetQuest is currently in the detailed design phase, having completed in 2005 all of the enabling technologies needed for the flight instrument. It will be the first space-based long baseline Michelson interferometer designed for precision astrometry. SIM will contribute strongly to many astronomical fields including stellar and galactic astrophysics, planetary systems around nearby stars, and the study of quasar and AGN nuclei. Using differential astrometry SIM will search for planets with masses as small as an Earth orbiting in the 'habitable zone' around the nearest stars, and could discover many dozen if Earth-like planets are common. It will characterize the multiple-planet systems that are now known to exist, and it will be able to search for terrestrial planets around all of the candidate target stars in the Terrestrial Planet Finder and Darwin mission lists. It will be capable of detecting planets around young stars, thereby providing insights into how planetary systems are born and how they evolve with time. Precision astrometry allows the measurement of accurate dynamical masses for stars in binary systems. SIM will observe significant numbers of very high- and low-mass stars, providing stellar masses to 1%, the accuracy needed to challenge physical models. Using precision proper motion measurements, SIM will probe the Galactic mass distribution, and through studies of tidal tails, the formation and evolution of the Galactic halo. SIM will contribute to cosmology through improved accuracy of the Hubble Constant. With repeated astrometric measurements of the nuclei of active galaxies, SIM will probe the dynamics of accretion disks around supermassive black holes, and the relativistic jets that emerge from them.

Description: The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick.

Description: The International X-ray Observatory requires mirror assemblies with unprecedented characteristics that cannot be provided by existing optical technologies. In the past several years, the project has supported a vigorous mirror technology development program. This program includes the fabrication of lightweight mirror segments by slumping commercially available thin glass sheets, the support and mounting of these thin mirror segments for accurate metrology, the mounting and attachment of these mirror segments for the purpose of X-ray tests, and development of methods for aligning and integrating these mirror segments into mirror assemblies. This paper describes our efforts and developments in these areas.

Description: The Swift X-ray Telescope (XRT) is a CCD based X-ray telescope designed for localization, spectroscopy and long term light curve monitoring of Gamma-Ray Bursts and their X-ray afterglows. Since the launch of Swift in November 2004, the XRT has undergone significant evolution in the way it is operated. Shortly after launch there was a failure of the thermo-electric cooler on the XRT CCD, which led to the XRT team being required to devise a method of keeping the XRT CCD temperature below 50C utilizing only passive cooling by minimizing the exposure of the XRT radiator to the Earth. We present in this paper an update on how the modeling of this passive cooling method has improved in first -1000 days since the method was devised, and the success rate of this method in day-to-day planning. We also discuss the changes to the operational modes and onboard software of the XRT. These changes include improved rapid data product generation in order to improve speed of rapid Gamma-Ray Burst response and localization to the community; changes to the way XRT observation modes are chosen in order to better fine tune data aquisition to a particular science goal; reduction of "mode switching" caused by the contamination of the CCD by Earth light or high temperature effects.

Description: We presented Spitzer Infrared Spectrograph (IRS) observations of two objects of the Taurus population that show unambiguous signs of clea,ring in their inner disks. In one of the objects, DM Tau, the outer disk is truncated at 3 AU; this object is akin to another recently reported in Taurus, CoKu Tau/4, in that the inner disk region is free of small dust. Unlike CoKu Tau/4, however, this star is still accreting, so optically thin gas should still remain in the inner disk region. The other object, GM Aur, also accreting, has about 0.02 lunar masses of small dust in the inner disk region within about 5 AU, consistent with previous reports. However, the IRS spectrum clearly shows that the optically thick outer disk has an inner truncation at a much larger radius than previously suggested, of order 24 AU. These observations provide strong evidence for the presence of gaps in protoplanetary disks.

Description: MESSENGER's third flyby of Mercury en route to orbit insertion about the innermost planet took place on 29 September 2009. The earlier 14 January and 6 October 2008 encounters revealed that Mercury's magnetic field is highly dipolar and stable over the 35 years since its discovery by Mariner 10; that a structured, temporally variable exosphere extends to great altitudes on the dayside and forms a long tail in the anti-sunward direction; a cloud of planetary ions encompasses the magnetosphere from the dayside bow shock to the downstream magnetosheath and magnetotail; and that the magnetosphere undergoes extremely intense magnetic reconnect ion in response to variations in the interplanetary magnetic field. Here we report on new results derived from observations from MESSENGER's Mercury Atmospheric and Surface Composition Spectrometer (MASCS), Magnetometer (MAG), and Energetic Particle and Plasma Spectrometer (EPPS) taken during the third flyby.

Description: This document, which is directed at the fishing sector, researchers, conservationists and fishery administrators, was developed by researchers who are members of the Specialists Group for Marine Turtle Research and conservation in the Southwestern Atlantic Ocean (SWA) in response to the urgent need to evaluate the impact generated on sea turtles by fisheries. Historically, sea turtle conservation efforts have focused almost exclusively on the protection of nesting beaches. Nevertheless, over the last decade, research has proved incidental mortality as a result of fishing activities to be one of the greatest threats to these animals. This type of interaction is not only problematic for turtles, but also generates financial losses for fishermen and businesses. In spite of the efforts that are currently underway, researchers still do not have a detailed understanding of the impact that bycatch produces on sea turtle populations in the SWA. We have a long way to go before its effects can be minimized. Further research is needed regarding the biology and ecology of the various turtle species as well as the effective application of mitigation measures. The life cycles of sea turtles are long and complex. Turtles occupy various ecosystems (nesting beaches, coastal, neritic and oceanic zones, as well as pelagic and demersal areas) throughout their lifetimes, transcending various Exclusive Economic Zones and International Waters. The five species that inhabit the SWA region perform vast feeding and reproductive migrations, traveling through areas where many different fishing fleets operate. Therefore, sea turtles in the SWA interact with virtually all fisheries. These circumstances make it necessary to carry out biological, fishing related and conservation studies on a regional level. The efficiency of the existing international and national legal instruments has yet to be determined, in terms of their effectiveness in protecting sea turtles. In some cases, legislation that is specifically related to the interaction between fisheries and turtles does exist, such as those laws requiring the mandatory use of turtle excluding devices (TEDs). There are also explicit bans on sea turtle capture. Nevertheless, none of these regulations prevent sea turtle bycatch. Although some regional legal instruments are needed, these and the existing legislation will only be effective if they are accompanied by a broader range of permanent education and control measures, to achieve the commitment of all the parties involved. The ecosystem approach is gaining popularity among fishery administration organizations. Research and conservation efforts should also be moving in that direction. A regional and international effort is required in order to compile information regarding the bycatch produced by the various types of fisheries and fleets operating in the area. The enormous increase in fishing pressure that these fleets are exerting in this area has not been accompanied by an increase in information regarding the bycatch of species that have no commercial value. Pelagic longlining is one of the fishing methods, which must be most closely monitored, due to the high levels of bycatch that it produces, as well its ample distribution throughout the region, and the high level of fishing effort that it accounts for. Coastal trawlers and gillnetters must also be considered critical players, because they too produce a large rate of bycatch. These are the three types of fisheries that are most broadly distributed throughout the region, accounting for the majority of the fishing effort. Most of the institutions that work toward sea turtle conservation in the area have only begun to address the issue of bycatch over the last decade. This timeframe is reflected in the scope and quantity of the available publications, as well as the progress of activities directed at mitigating this problem. All of the institutions that have been mentioned in this report have made the gathering of information regarding interaction between sea turtles and fisheries one of their top priorities. Some institutions are even developing working programs for monitoring fisheries and testing mitigation measures. Many of these institutions have managed to develop adequate relationships with fishermen, ship owners and administrators. Nevertheless, limited access to funding is an obstacle to the development and testing of mitigation measures. The SWA network, which is a very valuable instrument that was created in 2003, has allowed the region’s institutions and researchers to exchange information and share their experience, in addition to lending each other support in carrying out joint activities, thus strengthening sea turtle conservation efforts. The capacity demonstrated so far by the region’s researchers and institutions, testifies to their ability to continue to make progress in knowledge generation and tests of bycatch mitigation measures.

Description: Published