The Microchannel X-ray Telescope on Board the SVOM Satellite

We present the Micro-channel X-ray Telescope (MXT), a new narrow-field (about 1{\deg}) telescope that will be flying on the Sino-French SVOM mission dedicated to Gamma-Ray Burst science, scheduled for launch in 2021. MXT is based on square micro pore optics (MPOs), coupled with a low noise CCD. The optics are based on a "Lobster Eye" design, while the CCD is a focal plane detector similar to the type developed for the seven eROSITA telescopes. MXT is a compact and light (<35 kg) telescope with a 1 m focal length, and it will provide an effective area of about 45 cmsq on axis at 1 keV. The MXT PSF is expected to be better than 4.2 arc min (FWHM) ensuring a localization accuracy of the afterglows of the SVOM GRBs to better than 1 arc min (90\% c.l. with no systematics) provided MXT data are collected within 5 minutes after the trigger. The MXT sensitivity will be adequate to detect the afterglows for almost all the SVOM GRBs as well as to perform observations of non-GRB astrophysical objects. These performances are fully adapted to the SVOM science goals, and prove that small and light telescopes can be used for future small X-ray missions.Comment: 6 pages, 6 figures, proceedings of the conference "Swift: 10 years of Discovery", Rome, December 2-5, 2014. To be published by Po

Spectral performance of the Microchannel X-ray Telescope on board the SVOM mission

The Microchannel X-ray Telescope (MXT) is an innovative compact X-ray instrument on board the SVOM astronomical mission dedicated to the study of transient phenomena such as gamma-ray bursts. During 3 weeks, we have tested the MXT flight model at the Panter X-ray test facility under the nominal temperature and vacuum conditions that MXT will undergo in-flight. We collected data at series of characteristic energies probing the entire MXT energy range, from 0.28 keV up to 9 keV, for multiple source positions with the center of the point spread function (PSF) inside and outside the detector field of view (FOV). We stacked the data of the positions with the PSF outside the FOV to obtain a uniformly illuminated matrix and reduced all data sets using a dedicated pipeline. We determined the best spectral performance of MXT using an optimized data processing, especially for the energy calibration and the charge sharing effect induced by the pixel low energy thresholding. Our results demonstrate that MXT is compliant with the instrument requirement regarding the energy resolution (<80 eV at 1.5 keV), the low and high energy threshold, and the accuracy of the energy calibration ($\pm$20 eV). We also determined the charge transfer inefficiency (~$10^{-5}$) of the detector and modeled its evolution with energy prior to the irradiation that MXT will undergo during its in-orbit lifetime. Finally, we measured the relation of the energy resolution as function of the photon energy. We determined an equivalent noise charge of 4.9 $\pm$ 0.2 e- rms for the MXT detection chain and a Fano factor of 0.131 $\pm$ 0.003 in silicon at 208 K, in agreement with previous works. This campaign confirmed the promising scientific performance that MXT will be able to deliver during the mission lifetime.Comment: 20 pages, 10 figures, accepted for publication in Experimental Astronom

ART-XC: A Medium-energy X-ray Telescope System for the Spectrum-R-Gamma Mission

The ART-XC instrument is an X-ray grazing-incidence telescope system in an ABRIXAS-type optical configuration optimized for the survey observational mode of the Spectrum-RG astrophysical mission which is scheduled to be launched in 2011. ART-XC has two units, each equipped with four identical X-ray multi-shell mirror modules. The optical axes of the individual mirror modules are not parallel but are separated by several degrees to permit the four modules to share a single CCD focal plane detector, 1/4 of the area each. The 450-micron-thick pnCCD (similar to the adjacent eROSITA telescope detector) will allow detection of X-ray photons up to 15 keV. The field of view of the individual mirror module is about 18 x 18 arcminutes(exp 2) and the sensitivity of the ART-XC system for 4 years of survey will be better than 10(exp -12) erg s(exp -1) cm(exp -2) over the 4-12 keV energy band. This will allow the ART-XC instrument to discover several thousand new AGNs

The Scientific Performance of the Microchannel X-ray Telescope on board the SVOM Mission

The Microchannel X-ray Telescope (MXT) will be the first focusing X-ray telescope based on a "Lobster-Eye" optical design to be flown on Sino-French mission SVOM. SVOM will be dedicated to the study of Gamma-Ray Bursts and more generally time-domain astrophysics. The MXT telescope is a compact (focal length ~ 1.15 m) and light (< 42 kg) instrument, sensitive in the 0.2--10 keV energy range. It is composed of an optical system, based on micro-pore optics (MPOs) of 40 micron pore size, coupled to a low-noise pnCDD X-ray detector. In this paper we describe the expected scientific performance of the MXT telescope, based on the End-to-End calibration campaign performed in fall 2021, before the integration of the SVOM payload on the satellite.Comment: 22 pages, 12 figures, accepted for publication in Experimental Astronom

Feedback and feeding in the context of galaxy evolution with SPICA: direct characterization of molecular outflows and inflows

A far-infrared observatory such as the {\it SPace Infrared telescope for Cosmology and Astrophysics} ({\it SPICA}), with its unprecedented spectroscopic sensitivity, would unveil the role of feedback in galaxy evolution during the last $\sim10$ Gyr of the Universe ($z=1.5-2$), through the use of far- and mid-infrared molecular and ionic fine structure lines that trace outflowing and infalling gas. Outflowing gas is identified in the far-infrared through P-Cygni line shapes and absorption blueshifted wings in molecular lines with high dipolar moments, and through emission line wings of fine-structure lines of ionized gas. We quantify the detectability of galaxy-scale massive molecular and ionized outflows as a function of redshift in AGN-dominated, starburst-dominated, and main-sequence galaxies, explore the detectability of metal-rich inflows in the local Universe, and describe the most significant synergies with other current and future observatories that will measure feedback in galaxies via complementary tracers at other wavelengths.Comment: This paper belongs to the SPICA Special Issue on PASA. Accepted for publication in PAS

The eROSITA X-ray telescope on SRG

eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the primary instrument on the Spectrum-Roentgen-Gamma (SRG) mission, which was successfully launched on July 13, 2019, from the Baikonour cosmodrome. After the commissioning of the instrument and a subsequent calibration and performance verification phase, eROSITA started a survey of the entire sky on December 13, 2019. By the end of 2023, eight complete scans of the celestial sphere will have been performed, each lasting six months. At the end of this program, the eROSITA all-sky survey in the soft X-ray band (0.2-2.3 keV) will be about 25 times more sensitive than the ROSAT All-Sky Survey, while in the hard band (2.3-8 keV) it will provide the first ever true imaging survey of the sky. The eROSITA design driving science is the detection of large samples of galaxy clusters up to redshifts z &gt; 1 in order to study the large-scale structure of the universe and test cosmological models including Dark Energy. In addition, eROSITA is expected to yield a sample of a few million AGNs, including obscured objects, revolutionizing our view of the evolution of supermassive black holes. The survey will also provide new insights into a wide range of astrophysical phenomena, including X-ray binaries, active stars, and diffuse emission within the Galaxy. Results from early observations, some of which are presented here, confirm that the performance of the instrument is able to fulfil its scientific promise. With this paper, we aim to give a concise description of the instrument, its performance as measured on ground, its operation in space, and also the first results from in-orbit measurements

National Government Responses to Marine Stewardship Council (MSC) Fisheries Certification: Insights from Atlantic Canada

Over the last decade, the proliferation of social and environmental certification programmes has attracted the attention of a growing number of political scientists interested in new forms of ‘private’ transnational governance. However, we still lack analyses on the nature and extent of different state responses to and involvement in new private transnational governance arrangements in particular sectors and in different jurisdictions. This paper advances our understanding of the interactions between nation-state and private transnational modes of governance by analysing the role of national government authorities in Marine Stewardship Council (MSC) fisheries certification in Atlantic Canada, known more for the disastrous collapse of Northern cod stocks than good marine stewardship. Focusing on the 2008 certification of Northern shrimp (Pandalus borealis) fisheries off the Province of Newfoundland and Labrador, the analysis finds that the implementation and maintenance of MSC certification in this case depended on significant support from government authorities. The delicate legitimacy of both authorities face a period of uncertainty in this case since some certified shrimp stocks appear to be in decline and perhaps also migrating northward off Newfoundland and Labrador

Synaptic Reorganization in the Adult Rat's Ventral Cochlear Nucleus following Its Total Sensory Deafferentation

Ablation of a cochlea causes total sensory deafferentation of the cochlear nucleus in the brainstem, providing a model to investigate nervous degeneration and formation of new synaptic contacts in the adult brain. In a quantitative electron microscopical study on the plasticity of the central auditory system of the Wistar rat, we first determined what fraction of the total number of synaptic contact zones (SCZs) in the anteroventral cochlear nucleus (AVCN) is attributable to primary sensory innervation and how many synapses remain after total unilateral cochlear ablation. Second, we attempted to identify the potential for a deafferentation-dependent synaptogenesis. SCZs were ultrastructurally identified before and after deafferentation in tissue treated for ethanolic phosphotungstic acid (EPTA) staining. This was combined with pre-embedding immunocytochemistry for gephyrin identifying inhibitory SCZs, the growth-associated protein GAP-43, glutamate, and choline acetyltransferase. A stereological analysis of EPTA stained sections revealed 1.11±0.09 (S.E.M.)×109 SCZs per mm3 of AVCN tissue. Within 7 days of deafferentation, this number was down by 46%. Excitatory and inhibitory synapses were differentially affected on the side of deafferentation. Excitatory synapses were quickly reduced and then began to increase in number again, necessarily being complemented from sources other than cochlear neurons, while inhibitory synapses were reduced more slowly and continuously. The result was a transient rise of the relative fraction of inhibitory synapses with a decline below original levels thereafter. Synaptogenesis was inferred by the emergence of morphologically immature SCZs that were consistently associated with GAP-43 immunoreactivity. SCZs of this type were estimated to make up a fraction of close to 30% of the total synaptic population present by ten weeks after sensory deafferentation. In conclusion, there appears to be a substantial potential for network reorganization and synaptogenesis in the auditory brainstem after loss of hearing, even in the adult brain

Marking their own homework: The pragmatic and moral legitimacy of industry self-regulation

When is industry self-regulation (ISR) a legitimate form of governance? In principle, ISR can serve the interests of participating companies, regulators and other stakeholders. However, in practice, empirical evidence shows that ISR schemes often under-perform, leading to criticism that such schemes are tantamount to firms marking their own homework. In response, this paper explains how current management theory on ISR has failed to separate the pragmatic legitimacy of ISR based on self-interested calculations, from moral legitimacy based on normative approval. The paper traces three families of management theory on ISR and uses these to map the pragmatic and moral legitimacy of ISR schemes. It identifies tensions between the pragmatic and moral legitimacy of ISR schemes, which the current ISR literature does not address, and draws implications for the future theory and practice of ISR