Search

We present an enhanced version of the publicly-available Stripe 82X catalog (S82-XL), featuring a comprehensive set of 22,737 unique X-ray point sources identified with a significance $\gtrsim 4\sigma$. This catalog is four times larger than the original Stripe 82X catalog, by including additional archival data from the Chandra and XMM-Newton telescopes. Now covering $\sim54.8$ deg$^2$ of non-overlapping sky area, the S82-XL catalog roughly doubles the area and depth of the original catalog, with limiting fluxes (half-area fluxes) of 3.4$\times 10^{-16}$ (2.4$\times 10^{-15}$), 2.9$\times 10^{-15}$ (1.5$\times 10^{-14}$), and 1.4$\times 10^{-15}$ (9.5$\times 10^{-15}$) erg s$^{-1}$ cm$^{-2}$ across the soft (0.5-2 keV), hard (2-10 keV), and full (0.5-10 keV) bands, respectively. S82-XL occupies a unique region of flux-area parameter space compared to other X-ray surveys, identifying sources with rest-frame luminosities from $1.2\times 10^{38}$ to $1.6\times 10^{47}$ erg s$^{-1}$ in the 2-10 keV band (median X-ray luminosity, $7.2\times 10^{43}$ erg s$^{-1}$), and spectroscopic redshifts up to $z\sim6$. By using hardness ratios, we derived Active Galactic Nuclei (AGNs) obscuration obtaining a median value of $N_H=21.6_{-1.6}^{+1.0}$, and an overall, obscured fraction ($\log N_H/\mathrm{cm^{-2}}>22$) of $\sim 36.9\%$. S82-XL serves as a benchmark in X-ray surveys and, with its extensive multiwavelength data, is especially valuable for comprehensive studies of luminous AGNs., Comment: Accepted for publication in ApJ

We present the third catalog release of the wide-area (31.3 deg$^2$) Stripe 82 X-ray survey. This catalog combines previously published X-ray source properties with multiwavelength counterparts and photometric redshifts, presents 343 new spectroscopic redshifts, and provides black hole masses for 1297 Type 1 Active Galactic Nuclei (AGN). With spectroscopic redshifts for 3457 out of 6181 Stripe 82X sources, the survey has a spectroscopic completeness of 56%. This completeness rises to 90% when considering the contiguous portions of the Stripe 82X survey with homogeneous X-ray coverage at an optical magnitude limit of $r<22$. Within that portion of the survey, 23% of AGN can be considered obscured by being either a Type 2 AGN, reddened ($R-K > 4$, Vega), or X-ray obscured with a column density $N_{\rm H} > 10^{22}$ cm$^{-2}$. Unlike other surveys, there is only a 18% overlap between Type 2 and X-ray obscured AGN. We calculated black hole masses for Type 1 AGN that have SDSS spectra using virial mass estimators calibrated on the H$\beta$,MgII, H$\alpha$, and CIV emission lines. We find wide scatter in these black hole mass estimates, indicating that statiscal analyses should use black hole masses calculated from the same formula to minimize bias. We find that the AGN with the highest X-ray luminosities are accreting at the highest Eddington ratios, consistent with the picture that most black hole mass accretion happens in the phase when the AGN is luminous ($L_{\rm 2-10 keV} > 10^{45}$ erg s$^{-1}$)., Comment: 30 pages, 8 figures, accepted for publication to ApJ

Spectral energy distributions (SEDs) from X-ray to far-infrared (FIR) wavelengths are presented for a sample of 1246 X-ray luminous active galactic nuclei (AGN; $L_{0.5-10\rm{keV}}>10^{43}$ erg s$^{-1}$), with $z_{\rm{spec}}<1.2$, selected from Stripe 82X, COSMOS, and GOODS-N/S. The rest-frame SEDs show a wide spread ($\sim2.5$ dex) in the relative strengths of broad continuum features at X-ray, ultraviolet (UV), mid-infrared (MIR), and FIR wavelengths. A linear correlation (log-log slope of 0.7$\pm0.04$) is found between $L_{\rm{MIR}}$ and $L_{\rm{X}}$. There is significant scatter in the relation between the $L_{\rm{UV}}$ and $L_{\rm{X}}$ due to heavy obscuration, however the most luminous and unobscured AGN show a linear correlation (log-log slope of 0.8$\pm0.06$) in the relation above this scatter. The relation between $L_{\rm{FIR}}$ and $L_{\rm{X}}$ is predominantly flat, but with decreasing dispersion at $L_{\rm{X}}>10^{44}$ erg s$^{-1}$. The ratio between the "galaxy subtracted" bolometric luminosity and the intrinsic $L_{\rm{X}}$ increases from a factor of $\sim$$10-70$ from log $L_{\rm{bol}}/{\rm(erg\; s}^{-1})=44.5-46.5$. Characteristic SED shapes have been determined by grouping AGN based on relative strengths of the UV and MIR emission. The average $L_{1\mu\rm{m}}$ is constant for the majority of these SED shapes, while AGN with the strongest UV and MIR emission have elevated $L_{1\mu\rm{m}}$, consistent with the AGN emission dominating their SEDs at optical and NIR wavelengths. A strong correlation is found between the SED shape and both the $L_{\rm{X}}$ and $L_{\rm{bol}}$, such that $L_{\rm{bol}}/L_{\rm{X}}=20.4\pm1.8$, independent of the SED shape. This is consistent with an evolutionary scenario of increasing $L_{\rm{bol}}$ with decreasing obscuration as the AGN blows away circumnuclear gas., Comment: 24 pages, 20 figures, 4 appendix tables, Accepted to ApJ

The paper explores the optical properties of an exfoliated MoSe$_2$ monolayer implanted with Cr$^+$ ions, accelerated to 25 eV. Photoluminescence of the implanted MoSe$_2$ reveals an emission line from Cr-related defects that is present only under weak electron doping. Unlike band-to-band transition, the Cr-introduced emission is characterised by non-zero activation energy, long lifetimes, and weak response to the magnetic field. To rationalise the experimental results and get insights into the atomic structure of the defects, we modelled the Cr-ion irradiation process using ab-initio molecular dynamics simulations followed by the electronic structure calculations of the system with defects. The experimental and theoretical results suggest that the recombination of electrons on the acceptors, which could be introduced by the Cr implantation-induced defects, with the valence band holes is the most likely origin of the low energy emission. Our results demonstrate the potential of low-energy ion implantation as a tool to tailor the properties of 2D materials by doping.

Background: The choice of efficient antipsychotic therapy for schizophrenia relies on a time-consuming trial-and-error approach, whereas the social and economic burdens of the disease call for faster alternatives. Material \& methods: In a search for predictive biomarkers of antipsychotic response, blood methylomes of 28 patients were analyzed before and 4 weeks into risperidone therapy. Results: Several CpGs exhibiting response-specific temporal dynamics were identified in otherwise temporally stable methylomes and noticeable global response-related differences were observed between good and bad responders. These were associated with genes involved in immunity, neurotransmission and neuronal development. Polymorphisms in many of these genes were previously linked with schizophrenia etiology and antipsychotic response. Conclusion: Antipsychotic response seems to be shaped by both stable and medication-induced methylation differences., Comment: Epigenomics, 2023

We present a provenance model for the generic workflow of numerical Lattice Quantum Chromodynamics (QCD) calculations, which constitute an important component of particle physics research. These calculations are carried out on the largest supercomputers worldwide with data in the multi-PetaByte range being generated and analyzed. In the Lattice QCD community, a custom metadata standard (QCDml) that includes certain provenance information already exists for one part of the workflow, the so-called generation of configurations. In this paper, we follow the W3C PROV standard and formulate a provenance model that includes both the generation part and the so-called measurement part of the Lattice QCD workflow. We demonstrate the applicability of this model and show how the model can be used to answer some provenance-related research questions. However, many important provenance questions in the Lattice QCD community require extensions of this provenance model. To this end, we propose a multi-layered provenance approach that combines prospective and retrospective elements.

We present a machine-learning framework to accurately characterize morphologies of Active Galactic Nucleus (AGN) host galaxies within $z<1$. We first use PSFGAN to decouple host galaxy light from the central point source, then we invoke the Galaxy Morphology Network (GaMorNet) to estimate whether the host galaxy is disk-dominated, bulge-dominated, or indeterminate. Using optical images from five bands of the HSC Wide Survey, we build models independently in three redshift bins: low $(0

Long-term data-driven studies have become indispensable in many areas of science. Often, the data formats, structures and semantics of data change over time, the data sets evolve. Therefore, studies over several decades in particular have to consider changing database schemas. The evolution of these databases lead at some point to a large number of schemas, which have to be stored and managed, costly and time-consuming. However, in the sense of reproducibility of research data each database version must be reconstructable with little effort. So a previously published result can be validated and reproduced at any time. Nevertheless, in many cases, such an evolution can not be fully reconstructed. This article classifies the 15 most frequently used schema modification operators and defines the associated inverses for each operation. For avoiding an information loss, it furthermore defines which additional provenance information have to be stored. We define four classes dealing with dangling tuples, duplicates and provenance-invariant operators. Each class will be presented by one representative. By using and extending the theory of schema mappings and their inverses for queries, data analysis, why-provenance, and schema evolution, we are able to combine data analysis applications with provenance under evolving database structures, in order to enable the reproducibility of scientific results over longer periods of time. While most of the inverses of schema mappings used for analysis or evolution are not exact, but only quasi-inverses, adding provenance information enables us to reconstruct a sub-database of research data that is sufficient to guarantee reproducibility.

We constrain the intrinsic Eddington ratio (\lamEdd ) distribution function for local AGN in bins of low and high obscuration (log NH <= 22 and 22 < log NH < 25), using the Swift-BAT 70-month/BASS DR2 survey. We interpret the fraction of obscured AGN in terms of circum-nuclear geometry and temporal evolution. Specifically, at low Eddington ratios (log lamEdd < -2), obscured AGN outnumber unobscured ones by a factor of ~4, reflecting the covering factor of the circum-nuclear material (0.8, or a torus opening angle of ~ 34 degrees). At high Eddington ratios (\log lamEdd > -1), the trend is reversed, with < 30% of AGN having log NH > 22, which we suggest is mainly due to the small fraction of time spent in a highly obscured state. Considering the Eddington ratio distribution function of narrow-line and broad-line AGN from our prior work, we see a qualitatively similar picture. To disentangle temporal and geometric effects at high lamEdd, we explore plausible clearing scenarios such that the time-weighted covering factors agree with the observed population ratio. We find that the low fraction of obscured AGN at high lamEdd is primarily due to the fact that the covering factor drops very rapidly, with more than half the time is spent with < 10% covering factor. We also find that nearly all obscured AGN at high-lamEdd exhibit some broad-lines. We suggest that this is because the height of the depleted torus falls below the height of the broad-line region, making the latter visible from all lines of sight., Comment: Accepted by ApJL

We present X-ray spectral analysis of XMM and Chandra observations in the 31.3 deg$^2$ Stripe-82X (S82X) field. Of the 6181 X-ray sources in this field, we analyze a sample of 2937 active galactic nuclei (AGN) with solid redshifts and sufficient counts determined by simulations. Our results show a population with median values of spectral index $\Gamma=1.94_{-0.39}^{+0.31}$, column density log$\,N_{\mathrm{H}}/\mathrm{cm}^{-2}=20.7_{-0.5}^{+1.2}$ and intrinsic, de-absorbed, 2-10 keV luminosity log$\,L_{\mathrm{X}}/\mathrm{erg\,s}^{-1}=44.0_{-1.0}^{+0.7}$, in the redshift range 0-4. We derive the intrinsic fraction of AGN that are obscured ($22\leq\mathrm{log}\,N_{\mathrm{H}}/\mathrm{cm}^{-2}<24$), finding a significant increase in the obscured AGN fraction with redshift and a decline with increasing luminosity. The average obscured AGN fraction is $57\pm4\%$ for log$\,L_{\mathrm{X}}/\mathrm{erg\,s}^{-1}>43$. This work constrains the AGN obscuration and spectral shape of the still uncertain high-luminosity and high-redshift regimes (log$\,L_{\mathrm{X}}/\mathrm{erg\,s}^{-1}>45.5$, $z>3$), where the obscured AGN fraction rises to $64\pm12\%$. We report a luminosity and density evolution of the X-ray luminosity function, with obscured AGN dominating at all luminosities at $z>2$ and unobscured sources prevailing at log$\,L_{\mathrm{X}}/\mathrm{erg\,s}^{-1}>45$ at lower redshifts. Our results agree with evolutionary models in which the bulk of AGN activity is triggered by gas-rich environments and in a downsizing scenario. Also, the black hole accretion density (BHAD) is found to evolve similarly to the star formation rate density, confirming the co-evolution between AGN and host-galaxy, but suggesting different time scales in their growing history. The derived BHAD evolution shows that Compton-thick AGN contribute to the accretion history of AGN as much as all other AGN populations combined., Comment: 31 pages, 35 figures, Accepted for publication in ApJ

We introduce a novel machine learning framework for estimating the Bayesian posteriors of morphological parameters for arbitrarily large numbers of galaxies. The Galaxy Morphology Posterior Estimation Network (GaMPEN) estimates values and uncertainties for a galaxy's bulge-to-total light ratio ($L_B/L_T$), effective radius ($R_e$), and flux ($F$). To estimate posteriors, GaMPEN uses the Monte Carlo Dropout technique and incorporates the full covariance matrix between the output parameters in its loss function. GaMPEN also uses a Spatial Transformer Network (STN) to automatically crop input galaxy frames to an optimal size before determining their morphology. This will allow it to be applied to new data without prior knowledge of galaxy size. Training and testing GaMPEN on galaxies simulated to match $z < 0.25$ galaxies in Hyper Suprime-Cam Wide $g$-band images, we demonstrate that GaMPEN achieves typical errors of $0.1$ in $L_B/L_T$, $0.17$ arcsec ($\sim 7\%$) in $R_e$, and $6.3\times10^4$ nJy ($\sim 1\%$) in $F$. GaMPEN's predicted uncertainties are well-calibrated and accurate ($<5\%$ deviation) -- for regions of the parameter space with high residuals, GaMPEN correctly predicts correspondingly large uncertainties. We also demonstrate that we can apply categorical labels (i.e., classifications such as "highly bulge-dominated") to predictions in regions with high residuals and verify that those labels are $\gtrsim 97\%$ accurate. To the best of our knowledge, GaMPEN is the first machine learning framework for determining joint posterior distributions of multiple morphological parameters and is also the first application of an STN to optical imaging in astronomy., Comment: Accepted for publication in The Astrophysical Journal. We welcome comments and constructive criticism. Digital assets will be available at http://gampen.ghosharitra.com

We aim to determine the intrinsic far-Infrared (far-IR) emission of X-ray-luminous quasars over cosmic time. Using a 16 deg^2 region of the Stripe 82 field surveyed by XMM-Newton and Herschel Space Observatory, we identify 2905 X-ray luminous (LX > 10^42 erg/s) Active Galactic Nuclei (AGN) in the range z ~ 0-3. The IR is necessary to constrain host galaxy properties such as star formation rate (SFR) and gas mass. However, only 10% of our AGN are detected both in the X-ray and IR. Because 90% of the sample is undetected in the far-IR by Herschel, we explore the mean IR emission of these undetected sources by stacking their Herschel/SPIRE images in bins of X-ray luminosity and redshift. We create stacked spectral energy distributions from the optical to the far-IR, and estimate the median star formation rate, dust mass, stellar mass, and infrared luminosity using a fitting routine. We find that the stacked sources on average have similar SFR/L_bol ratios as IR detected sources. The majority of our sources fall on or above the main sequence line suggesting that X-ray selection alone does not predict the location of a galaxy on the main sequence. We also find that the gas depletion timescales of our AGN are similar to those of dusty star forming galaxies. This suggests that X-ray selected AGN host high star formation and that there are no signs of declining star formation., Comment: 26 pages, 14 figures, 5 tables, submitted to MNRAS

What do applications like semantic optimization, data exchange and integration, answering queries under dependencies, query reformulation with constraints, and data cleaning have in common? All these applications can be processed by the Chase, a family of algorithms for reasoning with constraints. While the theory of the Chase is well understood, existing implementations are confined to specific use cases and application scenarios, making it difficult to reuse them in other settings. ChaTEAU overcomes this limitation: It takes the logical core of the Chase, generalizes it, and provides a software library for different Chase applications in a single toolkit.

Graphite-moderated nuclear reactors have already produced more than 250000 tons of irradiated nuclear graphite, or i-graphite, world-wide. The sustainability of this technology relies on the end-of-life management of its moderator, which is activated into a long-lived nuclear waste, by neutron fluxes, during operating time. In particular, C14 is created. Nuclear transmutation, enabled by laser-driven particle acceleration, has been envisioned as a potential novel treatment scheme for long-lived nuclear waste. By triggering controlled nuclear reactions with energetic particles, long-lived radionuclides could be transformed into stable isotopes. Such a system could treat the C14 nuclei trapped within the i-graphite matrix, which is difficult to isolate by other means. This work performs a quantitative preliminary study of this transmutation scheme, in order to assess its feasibility at an industrial scale. The method used can be transposed to assess any transmutation scheme using a beam of particles directly sent on the material to be treated. First, a nuclear interaction channel which transmutes C14 nuclei without creating new long-lived radionuclides is identified. It consists in the choice of a type of particle, among which protons, gamma photons and neutrons can all be accelerated by laser-matter interaction; and it is completed by the adequate energy at which this particle must be sent on i-graphite. To that end, the nuclear cross-sections of C12, C13 and C14 are reviewed, neglecting other impurities in i-graphite. Then, based on the interaction channel identification, the energy cost of this scheme is estimated. Protons between 1 and 5 MeV make it possible to transmute C14 without creating any new long-lived activity. However, our result show that, even in this favorable reaction channel, the transmutation energy cost is too high for an i-graphite transmutation scheme to be feasible., Comment: Discussion clarified, results unchanged

Cosmic-ray-induced sputtering is one of the important desorption mechanisms at work in astrophysical environments. The chemical evolution observed in high-density regions, from dense clouds to protoplanetary disks, and the release of species condensed on dust grains, is one key parameter to be taken into account in interpretations of both observations and models. This study is part of an ongoing systematic experimental determination of the parameters to consider in astrophysical cosmic ray sputtering. As was already done for water ice, we investigated the sputtering yield as a function of ice mantle thickness for the two next most abundant species of ice mantles, carbon monoxide and carbon dioxide, which were exposed to several ion beams to explore the dependence with deposited energy. These ice sputtering yields are constant for thick films. It decreases rapidly for thin ice films when reaching the impinging ion sputtering desorption depth. An ice mantle thickness dependence constraint can be implemented in the astrophysical modelling of the sputtering process, in particular close to the onset of ice mantle formation at low visual extinctions., Comment: To appear in Astronomy & Astrophysics

Given a query result of a big database, why-provenance can be used to calculate the necessary part of this database, consisting of so-called witnesses. If this database consists of personal data, privacy protection has to prevent the publication of these witnesses. This implies a natural conflict of interest between publishing original data (provenance) and protecting these data (privacy). In this paper, privacy goes beyond the concept of personal data protection. The paper gives an extended definition of privacy as intellectual property protection. If the provenance information is not sufficient to reconstruct a query result, additional data such as witnesses or provenance polynomials have to be published to guarantee traceability. Nevertheless, publishing this provenance information might be a problem if (significantly) more tuples than necessary can be derived from the original database. At this point, it is already possible to violate privacy policies, provided that quasi identifiers are included in this provenance information. With this poster, we point out fundamental problems and discuss first proposals for solutions., Comment: Accepted at ProvenanceWeek 2020 ( https://iitdbgroup.github.io/ProvenanceWeek2020/ )

We present Multi-Unit Spectroscopic Explorer (MUSE) integral-field spectroscopy of ESO 253$-$G003, which hosts a known Active Galactic Nucleus (AGN) and the periodic nuclear transient ASASSN-14ko, observed as part of the All-weather MUse Supernova Integral-field of Nearby Galaxies (AMUSING) survey. The MUSE observations reveal that the inner region hosts two AGN separated by $1.4\pm0.1~\rm{kpc}$ ($\approx 1.\!\!^{\prime\prime}7$). The brighter nucleus has asymmetric broad, permitted emission-line profiles and is associated with the archival AGN designation. The fainter nucleus does not have a broad emission-line component but exhibits other AGN characteristics, including $v_{\rm{FWHM}}\approx 700~\rm{km}~\rm{s}^{-1}$ forbidden line emission, $\log_{10}(\rm{[OIII]}/\rm{H}\beta) \approx 1.1$, and high excitation potential emission lines such as [Fe$~$VII]$~\lambda6086$ and He$~$II$~\lambda4686$. The host galaxy exhibits a disturbed morphology with large kpc-scale tidal features, potential outflows from both nuclei, and a likely superbubble. A circular relativistic disk model cannot reproduce the asymmetric broad emission-line profiles in the brighter nucleus, but two non-axisymmetric disk models provide good fits to the broad emission-line profiles: an elliptical disk model and a circular disk + spiral arm model. Implications for the periodic nuclear transient ASASSN-14ko are discussed., Comment: 20 pages, 16 figures, and 2 tables. Accepted by MNRAS

Evolved stars near the tip of the red giant branch (TRGB) show solar-like oscillations with periods spanning hours to months and amplitudes ranging from $\sim$1 mmag to $\sim$100 mmag. The systematic detection of the resulting photometric variations with ground-based telescopes would enable the application of asteroseismology to a much larger and more distant sample of stars than is currently accessible with space-based telescopes such as \textit{Kepler} or the ongoing Transiting Exoplanet Survey Satellite (\textit{TESS}) mission. We present an asteroseismic analysis of 493 M giants using data from two ground-based surveys: the Asteroid Terrestrial-impact Last Alert System (ATLAS) and the All-Sky Automated Survey for Supernovae (ASAS-SN). By comparing the extracted frequencies with constraints from \textit{Kepler}, the Sloan Digital Sky Survey Apache Point Observatory Galaxy Evolution Experiment (APOGEE), and Gaia we demonstrate that ground-based transient surveys allow accurate distance measurements to oscillating M giants with a precision of $\sim$15$\%$. Using stellar population synthesis models we predict that ATLAS and ASAS-SN can provide asteroseismic distances to $\sim$2$\times$10$^{6}$ galactic M giants out to typical distances of $20-50 \; \rm{kpc}$, vastly improving the reach of Gaia and providing critical constraints for Galactic archaeology and galactic dynamics., Comment: 13 pages, 8 figures, 2 tables, accepted for publication in The Astronomical Journal

The occurrence of complex organic molecules (COMs) in the gas phase at low temperature in the dense phases of the ISM suggests that a non-thermal desorption mechanism is at work because otherwise, COMs should condense within a short timescale onto dust grains. Vacuum ultraviolet photodesorption has been shown to be much less efficient for complex organic molecules, such as methanol, because mostly photoproducts are ejected. The induced photolysis competes with photodesorption for large COMs, considerably lowering the efficiency to desorb intact molecules. We investigate the sputtering efficiency of complex organic molecules that are observed either in the ice mantles of interstellar dense clouds directly by infrared spectroscopy (CH3OH), or that are observed in the gas phase by millimeter telescopes (CH3COOCH3) and that could be released from interstellar grain surfaces. We irradiated ice films containing complex organic molecules (methanol and methyl acetate) and water with swift heavy ions in the electronic sputtering regime. We monitored the infrared spectra of the film as well as the species released to the gas phase with a mass spectrometer. We demonstrate that when methanol or methyl acetate is embedded in a water-ice mantle exposed to cosmic rays, a large portion is sputtered as an intact molecule, with a sputtering yield close to that of the main water-ice matrix. This must be even more true for more volatile ice matrices, such as those that are embedded in carbon monoxide. Cosmic rays penetrating deep into dense clouds provide an efficient mechanism to desorb complex organic molecules. Compared to VUV photons induced by the interaction of cosmic rays, a large portion desorb as intact molecules with a proportion corresponding to the time-dependent bulk composition of the ice mantle, the latter evolving with time as a function of fluence due to the radiolysis of the bulk., Comment: Corrected a copy/paste typo in Table 2: The CO2 stretch A value is 7.6d-17 Gerakines et al. (1995), replacing 1.8d-17 D'Hendecourt & Allamandola (1986)

Interstellar grain mantles present in dense interstellar clouds are in constant exchange with the gas phase via accretion and desorption mechanisms such as UV, X-ray photodesorption, cosmic ray induced sputtering, grain thermal fluctuations, and chemical reaction energy release. The relative importance of the various desorption mechanisms is of uttermost importance for astrophysical models to constrain the chemical evolution in such high density dense cloud regions. In this experimental work we investigated the sputtering yield as a function of ice mantle thickness, exposed to Xe ions at 95MeV. The ion induced ice phase transformation and the sputtering yield were simultaneously monitored by IR spectroscopy and mass spec- trometry, respectively. The sputtering yield is constant above a characteristic ice layer thickness and starts to decrease below this thickness. An estimate of the sputtering depth corresponding to this length can be evaluated. In these experiments the measured desorption depth corresponds to 30 ice layers. Assuming an effective cylindrical shape for the volume of sputtered molecules, the aspect ratio is close to unity; in the semi-infinite ice film case this ratio is the diameter to height of the cylinder. This result shows that most ejected molecules arise from a rather compact volume. The measured infinite thickness sputtering yield for water ice mantles scales as the square of the ion electronic stopping power (Se). We expect that the desorption depth dependence varies with Se^a , where a=0.5. Astrophysical models should take into account the thickness dependence constraints of these ice mantles in the interface regions when ices are close to their extinction threshold. In the very dense cloud regions, most of the water ice mantles are above this limit for the bulk of the cosmic rays., Comment: 6 pages, 5 figures

Mobility has become a basic premise of network communications, thereby requiring a native integration into 5G networks. Despite the numerous efforts to propose and to standardize effective mobility management models for IP, the result is a complex, poorly flexible set of mechanisms. The natural support for mobility offered by ICN (Information Centric Networking), makes it a good candidate to define a radically new solution relieving limitations of traditional approaches. If consumer mobility is supported in ICN by design, in virtue of its connectionless pull-based communication model, producer mobility is still an open challenge. In this work, we propose MAP-Me, an anchor-less solution to manage micro mobility of content producer via ICN name-based data plane, with support for latency-sensitive applications. First, we analyze MAP-Me performance and provide guarantees of correctness and stability. Further, we set up a realistic simulation environment in NDNSim 2.1 for MAP-Me evaluation and comparison against existing solutions: either random waypoint and trace-driven car mobility patterns are considered under 802.11 radio access. Results are encouraging and highlight the superiority of MAP-Me in terms of user performance and of network cost metrics.

Under cosmic irradiation, the interstellar water ice mantles evolve towards a compact amorphous state. Crystalline ice amorphisation was previously monitored mainly in the keV to hundreds of keV ion energies. We experimentally investigate heavy ion irradiation amorphisation of crystalline ice, at high energies closer to true cosmic rays, and explore the water-ice sputtering yield. We irradiated thin crystalline ice films with MeV to GeV swift ion beams, produced at the GANIL accelerator. The ice infrared spectral evolution as a function of fluence is monitored with in-situ infrared spectroscopy (induced amorphisation of the initial crystalline state into a compact amorphous phase). The crystalline ice amorphisation cross-section is measured in the high electronic stopping-power range for different temperatures. At large fluence, the ice sputtering is measured on the infrared spectra, and the fitted sputtering-yield dependence, combined with previous measurements, is quadratic over three decades of electronic stopping power. The final state of cosmic ray irradiation for porous amorphous and crystalline ice, as monitored by infrared spectroscopy, is the same, but with a large difference in cross-section, hence in time scale in an astrophysical context. The cosmic ray water-ice sputtering rates compete with the UV photodesorption yields reported in the literature. The prevalence of direct cosmic ray sputtering over cosmic-ray induced photons photodesorption may be particularly true for ices strongly bonded to the ice mantles surfaces, such as hydrogen-bonded ice structures or more generally the so-called polar ices., Comment: 22pages, 11 figures, accepted in A&A