Publication archive

Publication archive

Reference: ESA-LOFT-RP-0006, Issue 1, Revision 3.

LOFT, a Large Observatory for X-ray Timing, is one of five candidate missions for the M3 launch opportunity. A Preliminary Requirements Review (PRR) of all candidate missions has been performed to review their status in support of the M3 selection. This document reports the results of the technical and programmatic review for the LOFT mission candidate.

Published: 10 December 2013

Reference: ESA-ECHO-RP-0001, Issue 1.

EChO, an Exoplanet Characterisation Observatory, is one of five candidate missions for the M3 launch opportunity. A Preliminary Requirements Review (PRR) of all candidate missions has been performed to review their status in support of the M3 selection. This document reports the results of the technical and programmatic review for the EChO mission candidate.

Published: 25 November 2013
Reference: ESA/SRE(2013)2

This is the Assessment Study Report (also known as the Yellow Book) for EChO - a candidate mission for the M3 launch opportunity in Cosmic Vision.

Published: 16 December 2013
Reference: ESA/SRE(2013)3

This is the Assessment Study Report (also known as the Yellow Book) for LOFT - a candidate mission for the M3 launch opportunity in Cosmic Vision.

Published: 16 December 2013
Reference: ESA/SRE(2013)4

This is the Assessment Study Report (also known as the Yellow Book) for MarcoPolo-R - a candidate mission for the M3 launch opportunity in Cosmic Vision.

Published: 16 December 2013
Reference: ESA/SRE(2013)6.

This is the Assessment Study Report (also known as the Yellow Book) for STE-QUEST - a candidate mission for the M3 launch opportunity in Cosmic Vision.

Published: 16 December 2013
Reference: SRE-PA/2011.037

This document provides the top-level science requirements for the Exoplanet Characterisation Observatory (EChO), a dedicated mission to investigate exoplanetary atmospheres. The EChO mission was proposed to ESA in response to the M3 call in ESA's Cosmic Vision programme, and was selected for assessment in February 2011. The mission in turn builds on a concept for an Exoplanet Spectroscopy Mission (ESM) that was recommended by the Exoplanetary RoadMap Advisory Team (EPRAT) in 2009/10 for study by ESA. The science requirements were initially derived from the science objectives described in the EChO M3 proposal and have been refined and updated following discussions between the EChO science team and the ESA internal study team. This document was first written as input to the CDF study starting in June 2011. It has been updated continuously since, and will continue to be refined over the course of the study. The aim of this document is to detail the science requirements for all aspects of the mission. As such, the document provides a means by which to understand, trace and support a detailed analysis of the relationship between the science objectives of the mission and the specification of the mission and payload.

Published: 13 December 2013
Noble gas molecules have not hitherto been detected in space. From spectra obtained with the Herschel Space Observatory, we report the detection of emission in the 617.5- and 1234.6-gigahertz J=1-0 and 2-1 rotational lines of 36ArH+ at several positions in the Crab Nebula, a supernova remnant known to contain both molecular hydrogen and regions of enhanced ionized argon emission. Argon-36 is believed to have originated from explosive nucleosynthesis in massive stars during core-collapse supernova events. Its detection in the Crab Nebula, the product of such a supernova event, confirms this expectation. The likely excitation mechanism for the observed 36Ar emission lines is electron collisions in partially ionized regions with electron densities of a few hundred per centimeter cubed.
Published: 13 December 2013
In November and December 2012 the Hubble Space Telescope (HST) imaged Europa's ultraviolet emissions in the search for vapor plume activity. We report statistically significant coincident surpluses of hydrogen Lyman-alpha and oxygen OI130.4 nm emissions above the southern hemisphere in December 2012. These emissions are persistently found in the same area over ~7 hours, suggesting atmospheric inhomogeneity; they are consistent with two 200 km high plumes of water vapor with line-of-sight column densities of about 1020 m-2. Nondetection in November and in previous HST images from 1999 suggests varying plume activity that might depend on changing surface stresses based on Europa's orbital phases. The plume is present when Europa was near apocenter, and not detected close to its pericenter in agreement with tidal modeling predictions.
Published: 12 December 2013
Reference: SRE-PA/2011.038/

EChO (Exoplanet Characterisation Observatory) is an M-class mission candidate for the M3 slot within the Cosmic Vision programme, for a planned launch between 2022 and 2024. EChO, with 3 other science missions, was recommended by the Space Science Advisory Committee (SSAC) to enter an assessment study (Phase 0), starting by an ESA internal study followed by parallel industrial study activities.

Within the M3 boundary conditions, the readiness for launch by 2022/2024 is a severe requirement which in practice requires designing the space segment without major technology developments and with minimum developments risks. Therefore, only technologies with estimated Technology Readiness Levels (TRL) of at least 5 by the end of the Phase A/B1 (estimated at the end of 2015) may be used.

This document aims at providing a complete and comprehensive list of all high level mission requirements (including spacecraft and payload, launcher, ground segment and operations) necessary to achieve the science goals detailed in [EChO SciRD (Science Requirements Document), SRE-PA/2011.037/]. It is hence an applicable document that all mission design activities shall comply with. The MRD will be further reviewed matching the results of future study phases (e.g. definition phase) to finally evolve in the System Requirements Document at the start of the implementation phase.

Published: 12 December 2013
A Senior Survey Committee was appointed by the Director of Science and Robotic Exploration to advise him on the definition of the science themes and questions to be addressed by the L2 and L3 missions, the next large missions in the Cosmic Vision programme. This report (pdf format, 23.4 MB) represents the synthesis of the committee's work and outlines their recommendations.
Published: 28 November 2013
The Cluster mission operated a "tilt campaign" during the month of May 2008. Two of the four identical Cluster spacecraft were placed at a close distance (~50 km) from each other and the spin axis of one of the spacecraft pair was tilted by an angle of ~46°. This gave the opportunity, for the first time in space, to measure global characteristics of AC electric field, at the sensitivity available with long boom (88 m) antennas, simultaneously from the specific configuration of the tilted pair of satellites and from the available base of three satellites placed at a large characteristic separation (~1 RE). This paper describes how global characteristics of radio waves, in this case the configuration of the electric field polarization ellipse in 3-D-space, are identified from in situ measurements of spin modulation features by the tilted pair, validating a novel experimental concept. In the event selected for analysis, non-thermal continuum (NTC) waves in the 15-25 kHz frequency range are observed from the Cluster constellation placed above the polar cap. The observed intensity variations with spin angle are those of plane waves, with an electric field polarization close to circular, at an ellipticity ratio e = 0.87. We derive the source position in 3-D by two different methods. The first one uses ray path orientation (measured by the tilted pair) combined with spectral signature of magnetic field magnitude at source. The second one is obtained via triangulation from the three spacecraft baseline, using estimation of directivity angles under assumption of circular polarization. The two results are not compatible, placing sources widely apart. We present a general study of the level of systematic errors due to the assumption of circular polarization, linked to the second approach, and show how this approach can lead to poor triangulation and wrong source positioning.
[Remainder of abstract truncated, due to character limitations]
Published: 26 November 2013
Context. Massive stars form in groups and their winds and supernova explosions create superbubbles up to kpc in size. The fate of their ejecta is of vital importance for the dynamics of the interstellar medium, for chemical evolution models, and the chemical enrichment of galactic halos and the intergalactic medium. However, ejecta kinematics and the characteristic scales in space and time have not been explored in great detail beyond ~10 Ka. Aims. Through measurement of radioactive 26Al with its decay time constant at ~106 years, we aim to trace the kinematics of cumulative massive-star and supernova ejecta independent of the uncertain gas parameters over million-year time scales. Our goal is to identify the mixing time scale and the spatio-kinematics of such ejecta from the pc to kpc scale in our Milky Way. Methods. We use the SPI spectrometer on the INTEGRAL observatory and its observations along the Galactic ridge to trace the detailed line shape systematics of the 1808.63 keV gamma-ray line from 26Al decay. We determine line centroids and compare these to Doppler shift expectations from large-scale systematic rotation around the Galaxy centre, as observed in other Galactic objects. Results. We measure the radial velocities of gas traced by 26Al, averaged over the line of sight, as a function of Galactic longitude. We find substantially higher velocities than expected from Galactic rotation, the average bulk velocity being ~200 km/s larger than predicted from Galactic rotation. The observed radial velocity spread implies a Doppler broadening of the gamma-ray line that is consistent with our measurements of the overall line width.
[Remainder of abstract truncated due to character limitations]
Published: 19 November 2013

Published online 13 November 2013.

Accreting black holes are known to power relativistic jets, both in stellar-mass binary systems and at the centres of galaxies. The power carried away by the jets, and, hence, the feedback they provide to their surroundings, depends strongly on their composition. Jets containing a baryonic component should carry significantly more energy than electron-positron jets. Energetic considerations and circular-polarization measurements have provided conflicting circumstantial evidence for the presence or absence of baryons in jets, and the only system in which they have been unequivocally detected is the peculiar X-ray binary SS 433. Here we report the detection of Doppler-shifted X-ray emission lines from a more typical black-hole candidate X-ray binary, 4U 1630-47, coincident with the reappearance of radio emission from the jets of the source. We argue that these lines arise from baryonic matter in a jet travelling at approximately two-thirds the speed of light, thereby establishing the presence of baryons in the jet. Such baryonic jets are more likely to be powered by the accretion disk than by the spin of the black hole, and if the baryons can be accelerated to relativistic speeds, the jets should be strong sources of gamma-rays and neutrino emission.

Published: 14 November 2013
Hubble Space Telescope observations of main-belt comet P/2013 P5 reveal an extraordinary system of six dust tails that distinguish this object from any other. Observations two weeks apart show dramatic morphological change in the tails while providing no evidence for secular fading of the object as a whole. Each tail is associated with a unique ejection date, revealing continued, episodic mass loss from the 0.24 +- 0.04 km radius nucleus over the last five months. As an inner-belt asteroid and probable Flora family member, the object is likely to be highly metamorphosed and unlikely to contain ice. The protracted period of dust release appears inconsistent with an impact origin, but may be compatible with a body that is losing mass through a rotational instability. We suggest that P/2013 P5 has been accelerated to breakup speed by radiation torques.
Published: 07 November 2013
The Sun Watcher with Active Pixels and Image Processing (SWAP) EUV solar telescope on board the Project for On-Board Autonomy 2 spacecraft has been regularly observing the solar corona in a bandpass near 17.4 nm since 2010 February. With a field of view of 54 × 54 arcmin, SWAP provides the widest-field images of the EUV corona available from the perspective of the Earth. By carefully processing and combining multiple SWAP images, it is possible to produce low-noise composites that reveal the structure of the EUV corona to relatively large heights. A particularly important step in this processing was to remove instrumental stray light from the images by determining and deconvolving SWAP's point-spread function from the observations. In this paper, we use the resulting images to conduct the first-ever study of the evolution of the large-scale structure of the corona observed in the EUV over a three year period that includes the complete rise phase of solar cycle 24. Of particular note is the persistence over many solar rotations of bright, diffuse features composed of open magnetic fields that overlie polar crown filaments and extend to large heights above the solar surface. These features appear to be related to coronal fans, which have previously been observed in white-light coronagraph images and, at low heights, in the EUV. We also discuss the evolution of the corona at different heights above the solar surface and the evolution of the corona over the course of the solar cycle by hemisphere.
Published: 01 November 2013
Gravitational lensing of the cosmic microwave background generates a curl pattern in the observed polarization. This "B-mode" signal provides a measure of the projected mass distribution over the entire observable Universe and also acts as a contaminant for the measurement of primordial gravity-wave signals. In this Letter we present the first detection of gravitational lensing B modes, using first-season data from the polarization-sensitive receiver on the South Pole Telescope (SPTpol). We construct a template for the lensing B-mode signal by combining E-mode polarization measured by SPTpol with estimates of the lensing potential from a Herschel-SPIRE map of the cosmic infrared background. We compare this template to the B modes measured directly by SPTpol, finding a nonzero correlation at 7.7 sigma significance. The correlation has an amplitude and scale dependence consistent with theoretical expectations, is robust with respect to analysis choices, and constitutes the first measurement of a powerful cosmological observable.
Published: 01 October 2013
Since the seasonal and spatial distribution of ozone on Mars was detected by the ultraviolet spectrometer onboard the spacecraft Mariner 7, our understanding has evolved considerably thanks to parallel efforts in observations and modelling. At low-to-mid latitudes, martian ozone is distributed vertically in two main layers, a near-surface layer and a layer at an altitude between 30 and 60 km. Here we report evidence from the SPICAM UV spectrometer onboard the Mars Express orbiter for the existence of a previously overlooked ozone layer that emerges in the southern polar night at 40–60 km in altitude, with no counterpart observed at the north pole. Comparisons with global climate simulations for Mars indicate that this layer forms as a result of the large-scale transport of oxygen-rich air from sunlit latitudes to the poles, where the oxygen atoms recombine to form ozone during the polar night. However, transport-driven ozone formation is counteracted in our simulations by the destruction of ozone by reactions with hydrogen radicals, whose concentrations vary seasonally on Mars, reflecting seasonal variations of water vapour. We conclude that the observed dichotomy between the ozone layers of the two poles, with a significantly richer layer in the southern hemisphere, can be explained by the interplay of these mechanisms.
Published: 30 September 2013
Published online 25 September 2013

It is thought that neutron stars in low-mass binary systems can accrete matter and angular momentum from the companion star and be spun-up to millisecond rotational periods. During the accretion stage, the system is called a low-mass X-ray binary, and bright X-ray emission is observed. When the rate of mass transfer decreases in the later evolutionary stages, these binaries host a radio millisecond pulsar whose emission is powered by the neutron stars rotating magnetic field. This evolutionary model is supported by the detection of millisecond X-ray pulsations from several accreting neutron stars and also by the evidence for a past accretion disc in a rotation-powered millisecond pulsar. It has been proposed that a rotation-powered pulsar may temporarily switch on during periods of low mass inflow in some such systems. Only indirect evidence for this transition has hitherto been observed. Here we report observations of accretion-powered, millisecond X-ray pulsations from a neutron star previously seen as a rotation-powered radio pulsar. Within a few days after a month-long X-ray outburst, radio pulses were again detected. This not only shows the evolutionary link between accretion and rotation-powered millisecond pulsars, but also that some systems can swing between the two states on very short timescales.
Published: 27 September 2013
17-Apr-2021 20:47 UT

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