Thermal Filters for the ATHENA X-IFU: Ongoing Activities Toward the Conceptual Design

ATHENA is the L2 mission selected by ESA to pursue the science theme “Hot and Energetic Universe.” One of the two focal plane instruments is the X-ray Integral Field Unit, an array of TES microcalorimeters operated at T $$<$$ 100 mK. To allow the X-ray photons focused by the telescope to reach the detector, windows have to be opened on the cryostat thermal shields. X-ray transparent filters need to be mounted on these open windows to attenuate the IR radiation from warm surfaces, to attenuate RF electromagnetic interferences on TES sensors and SQUID electronics, and to protect the detector from contamination. This paper reviews the ongoing activities driving the design of the X-IFU thermal …

Denegare iudicium e denegare actionem

The expressions denegare iudicium and denegare actionem are both used to point out the refusal on the part of the magistratus cum iurisdictione to grant the action. However, in the opinion of the author, these expressions have different meanings. Denegare iudicium is used in contexts that are not compatible with the granting of a formula provided with exceptiones; while denegare actionem is used when the praetor was given the opportunity either to refuse the granting of the action or to give a formula provided with exceptiones.

Supersaturation and activity-rotation relation in PMS stars: the young Cluster h Per

The magnetic activity of late-type MS stars is characterized by different regimes, and their activity levels are well described by Ro, the ratio between P_rot and the convective turnover time. Very young PMS stars show, similarly to MS stars, intense magnetic activity. However they do not show clear activity-rotation trends, and it still debated which stellar parameters determine their magnetic activity levels. To bridge the gap between MS and PMS stars, we studied the activity-rotation relation in the young cluster h Per, a ~13 Myr old cluster, that contains both fast and slow rotators, whose members have ended their accretion phase and have already developed a radiative core. It offers us…

The Origin of T Tauri X-ray Emission: New Insights from the Chandra Orion Ultradeep Project

We use the data of the Chandra Orion Ultradeep Project (COUP) to study the nearly 600 X-ray sources that can be reliably identified with optically well characterized T Tauri stars (TTS) in the Orion Nebula Cluster. We detect X-ray emission from more than 97% of the optically visible late-type (spectral types F to M) cluster stars. This proofs that there is no ``X-ray quiet'' population of late-type stars with suppressed magnetic activity. All TTS with known rotation periods lie in the saturated or super-saturated regime of the relation between activity and Rossby numbers seen for main-sequence (MS) stars, but the TTS show a much larger scatter in X-ray activity than seen for the MS stars. S…

Xrase: The X-Ray Spectroscopic Explorer

The X-Ray Spectroscopic Explorer (XRASE) has a unique combination of features that will make it possible to address many of NASA’s scientific goals. These include how galaxy clusters form, the physics and chemistry of the ISM, the heating of stellar coronae, the amount and content of intergalactic baryonic matter, the mass of black holes and the formation of disks and jets in AGN and galactic binaries. XRASE has a thin foil, multilayered telescope with a large collecting area up to 10 keV, especially in the Fe Kα region (1100 cm2). Its microcalorimeter array combines high energy resolution (7 eV at 6 keV) and efficiency with a field-of-view of 26 arcmin2. A deep orbit allows for long, conti…

ATHENA WFI optical blocking filters development status toward the end of the instrument phase-A

Copyright 2018 Society of Photo-Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. The Wide Field Imager (WFI) is one of the two instruments of the ATHENA astrophysics space mission approved by ESA as the second large mission in the Cosmic Vision 2015-2025 Science Programme. The WFI, based on a large array of depleted field effect transistors (DEPFET), will provide imaging in the 0.2-15 keV band over a 40'x40' field of view, simultaneously with spectrally an…

The Athena X-ray Integral Field Unit (X-IFU)

Event: SPIE Astronomical Telescopes + Instrumentation, 2016, Edinburgh, United Kingdom.

Sull'adozione da parte delle donne

X-ray and optical emission in protostellar jets: model predictions and comparison with observations

The stellar content of the XMM-Newton Bright Serendipitous Survey

Context: The comparison of observed counts in a given sky direction with predictions by Galactic models yields constraints to the spatial distribution and the stellar birthrate of young stellar populations. In this work we present the results of the analysis of the stellar content of the XMM-Newton Bright Serendipitous Survey (XBSS). This unbiased survey includes a total of 58 stellar sources selected in the 0.5 -- 4.5 keV energy band, having a limiting sensitivity of $10^{-2}$ cnt s$^{-1}$ and covering an area of 28.10 sq. deg. Aims: Our main goal is to understand the recent star formation history of the Galaxy in the vicinity of the Sun. Methods: We compare the observations with the predi…

The Palermo XACT facility: a new 35 m long soft x-ray beam-line for the development and calibration of next-generation x-ray observatories

The X-ray Astronomy Calibration and Testing (XACT) facility of the Instituto Nazionale di Astrofisica (INAF) at Osservatorio Astronomico di Palermo has recently undergone a major upgrade with the design and construction of a 35 meter long vacuum beam-line operating in the soft X-rays (0.1-20 keV) and the addition of new hardware to meet the requirements for testing and calibration of next generation X-ray missions. We report on the present configuration of the facility and briefly survey the range of its applications.

CSI 2264: Simultaneous optical and X-ray variability in pre-main sequence stars. I. Time resolved X-ray spectral analysis during optical dips and accretion bursts in stars with disks

Pre-main sequence stars are variable sources. In stars with disks, this variability is related to the morphology of the inner circumstellar region (&lt;0.1 AU) and that of the photosphere and corona, all impossible to be spatially resolved with present day techniques. This has been the main motivation for the Coordinated Synoptic Investigation of NGC 2264. In this paper, we focus on the stars with disks. We analyze the X-ray spectral properties extracted during optical bursts and dips in order to unveil the nature of these phenomena. We analyze simultaneous CoRoT and Chandra/ACIS-I observations to search for coherent optical and X-ray flux variability in stars with disks. Then, stars are an…

La relazione tra il kata podas e le traduzioni di Taleleo dei rescritti in latino del Codex

Il contributo mira a dimostrare, attraverso il confronto tra le traduzioni letterali di Taleleo e quelle dell'anonimo autore del kata podas, che la scelta dell'antecessore di cambiare metodo di insegnamento e non dettare più proprie traduzioni letterali dopo il terzo libro del Codice, non dipese da ragioni di metodo di insegnamento (come sostenuto in dottrina) ma da esigenze pratiche, legate al poco tempo avuto a disposizione per la redazione del commentario al secondo Codice di Giustiniano.

X-ray optical depth diagnostics of T Tauri accretion shocks

In classical T Tauri stars, X-rays are produced by two plasma components: a hot low-density plasma, with frequent flaring activity, and a high-density lower temperature plasma. The former is coronal plasma related to the stellar magnetic activity. The latter component, never observed in non-accreting stars, could be plasma heated by the shock formed by the accretion process. However its nature is still being debated. Our aim is to probe the soft X-ray emission from the high-density plasma component in classical T Tauri stars to check whether this is plasma heated in the accretion shock or whether it is coronal plasma. High-resolution X-ray spectroscopy allows us to measure individual line f…

X-ray flare oscillations track plasma sloshing along star-disk magnetic tubes in Orion star-forming region

Pulsing X-ray emission tracks the plasma echo traveling in an extremely long magnetic tube that flares in an Orion Pre-Main Sequence (PMS) star. On the Sun, flares last from minutes to a few hours and the longest-lasting typically involve arcades of closed magnetic tubes. Long-lasting X-ray flares are observed in PMS stars. Large-amplitude (~20%) long-period (~3 hours) pulsations are detected in the light curve of day-long flares observed by the Advanced CCD Imaging Spectrometer (ACIS) on-board Chandra from PMS stars in the Orion cluster. Detailed hydrodynamic modeling of two flares observed on V772 Ori and OW Ori shows that these pulsations may track the sloshing of plasma along a single l…

The Voyage of Metals in the Universe from Cosmological to Planetary Scales: the need for a Very High-Resolution, High Throughput Soft X-ray Spectrometer

Metals form an essential part of the Universe at all scales. Without metals we would not exist, and the Cosmos would look completely different. Metals are primarily born through nuclear processes in stars. They leave their cradles through winds or explosions, and then start their journey through space. This can lead them in and out of astronomical objects on all scales, ranging from comets, planets, stars, entire galaxies, groups and clusters of galaxies to the largest structures of the Universe. Their wanderings are fundamental in determining how these objects, and the entire universe, evolve. In addition, their bare presence can be used to trace what these structures look like. The scope …

CSI2264: Simultaneous optical and X-ray variability in the pre-main sequence stars of NGC2264. II: Photometric variability, magnetic activity, and rotation in classIII objects and stars with transition disks

Pre-main sequence stars are variable sources. In diskless stars this variability is mainly due to the rotational modulation of dark photospheric spots and active regions, as in main sequence stars even if associated with a stronger magnetic activity. Aims. We aim at analyzing the simultaneous optical and X-ray variability in these stars to unveil how the activity in the photosphere is connected with that in the corona, to identify the dominant surface magnetic activity, and to correlate our results with stellar properties, such as rotation and mass. Methods. We analyzed the simultaneous optical and X-ray variability in stars without inner disks (e.g., class III objects and stars with transi…

Il termine dell'expulsio del conduttore per mancato pagamento del canone nella locatio di aedes e di fundi

il lavoro è volto a fornire una spiegazione al dato apparentemente contraddittorio delle fonti, secondo le quali, il potere del locatore di espellere il conduttore per mancato pagamento del canone è talvolta immediato, tal altra subordinato al decorso di un biennio dalla scadenza del termine di pagamento della mercede. La soluzione proposta è quella di distinguere la locazione delle aedes da quella dei fundi: nel primo caso si tollerarono ritardi di pagamento della mercede fino a due anni; nel secondo caso, la giurisprudenza legittimò il locatore all'expulsio immediata del conduttore inadempiente all'obbligo di pagare il canone.

Il lessico giuridico dell'Eisagoge e delle Novelle di Leone VI il Saggio

The paper deals with the content of the Diccionario Juridico Bizantino Griego-Espanol in a critical view.

Conjectures regarding Thalelaios' commentary on the Novus Codex

Il contributo rinviene tracce di un precedente strato del commentario di Taleleo al codex repetitae praelectionis riferibile al Novus Codex Iustinianus. The paper find traces of a previous state of the Thalelaos' commentary on the codex repetitae praelectionis attributable to Novus Codex Justinian.

X-ray emission from early-type stars in the Orion Nebula Cluster

The X-ray properties of twenty ~1 Myr old O, B, and A stars of the Orion Trapezium are examined with data from the Chandra Orion Ultradeep Project (COUP). On the basis of simple theories for X-ray emission, we define two classes separated at spectral type B4: hotter stars have strong winds that may give rise to X-ray emission in small- or large-scale wind shocks, and cooler stars that should be X-ray dark due to their weaker winds and absence of outer convection zones where dynamos can generate magnetic fields. Only two of the massive stars show exclusively the constant soft-spectrum emission expected from the standard model for X-ray emission from hot stars involving many small shocks in a…

The stellar population of the Rosat North Ecliptic Pole survey

Context. X-ray surveys are a very efficient mean of detecting young stars and therefore allow us to study the young stellar population in the solar neighborhood and the local star formation history in the last billion of years. Aims. We want to study the young stellar population in the solar neighborhood, to constrain its spatial density and scale height as well as the recent local star formation history. Methods. We analyze the stellar content of the ROSAT North Ecliptic Pole survey, and compare the observations with the predictions derived from stellar galactic model. Since the ROSAT NEP survey is sensitive at intermediate fluxes is able to sample both the youngest stars and the intermedi…

Aulo Cascellio e i beneficia dei Triumviri. Nota minima su Val. Max. 6.2.12

The paper examines a well-known passage by Valerius Maximus, which refers to the episode of the refusal opposed by the jurist Aulus Cascellius to formulam componere, to assert in court beneficia granted by the triumviri. The author investigates the reasons for the refusal and whether this was opposed by Cascellius as a private jurist or by holding a public function.

Deep X-ray view of the Class I YSO Elias 29 with XMM-Newton and NuSTAR

[Abridged] We investigated the X-ray characteristics of the Class I YSO Elias 29 with joint XMM-Newton and NuSTAR observations of 300 ks and 450 ks, respectively. These are the first observations of a very young (&lt;1 Myr) stellar object in a band encompassing simultaneously both soft and hard X-rays. In addition to the hot Fe complex at 6.7 keV, we observed fluorescent emission from Fe at $\sim6.4$ keV, confirming the previous findings. The line at 6.4 keV is detected during quiescent and flaring states and its flux is variable. The equivalent width is found varying in the $\approx 0.15--0.5$ keV range. These values make unrealistic a simple model with a centrally illuminated disk and sug…

Subphotospheric convection and magnetic activity dependence on metallicity and age: Models and tests

We present an extensive study on the dependence of the convective turnover time (conv) on the stellar metallicity and age for main-sequence stars of masses 0.6{1.6 M. To this aim we have used and compared predictions by stellar models based on the classical Mixing Length Theory and models incorporating a Full Spectrum of Turbulence treatment of subphotospheric convection. We show that the metallicity eect is relevant for dG stars but negligible for dK stars, while stellar age is important when computing the turnover times for red dwarfs younger than logt 8:5 yr. A scatter by up to a factor 3 could be spuriously introduced in the activity vs. Rossby number relationships if such eects are neg…

The filter wheel and filters development for the X-IFU instruments onboard Athena

Athena is the large mission selected by ESA in 2013 to investigate the science theme “Hot and Energetic Universe” and presently scheduled for launch in 2028. One of the two instruments located at the focus of the 12 m-long Athena telescope is the X-ray Integral Field Unit (X-IFU). This is an array of TES microcalorimeters that will be operated at temperatures of 50 mK in order to perform high resolution spectroscopy with an energy resolution down to 2.5 eV at energies &lt; 7 keV. In order to cope with the large dynamical range of X-ray fluxes spanned by the celestial objects Athena will be observing, the X-IFU will be equipped with a filter wheel. This will allow the user to fine tune the i…

Ricerche in tema di società questuarie

Intorno al regime delle società di tipo questuario – riconducibili agli schemi teorici della societas universorum quae ex quaestu veniunt – e delle società unius alicuius negotiationis e unius rei, si profusero gli sforzi interpretativi dei giuristi romani, fin dalla fine dell’età repubblicana. La monografia scientifica ripercorre le tracce della individuazione della nozione stessa di quaestus (guadagno), con particolare riferimento alla inclusione al suo interno delle donazioni cd. remuneratorie; ancora, ricostruisce il dibattito giurisprudenziale sorto intorno alla questione se i soci – nella determinazione delle quote – dovessero rispettare una proporzione rispetto ai conferimenti, con u…

The x-ray microcalorimeter spectrometer onboard Athena

Trabajo presentado a la conferencia: "Space Telescopes and Instrumentation: Ultraviolet to Gamma Ray" celebrada en Amsterdam (Holanda) el 1 de julio de 2012.-- et al.

ATHENA X-IFU thermal filters development status toward the end of the instrument phase-A

Copyright 2018 Society of Photo-Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. The X-ray Integral Field Unit (X-IFU) is one of the two instruments of the Athena astrophysics space mission approved by ESA in the Cosmic Vision 2015-2025 Science Programme. The X-IFU consists of a large array of transition edge sensor micro-calorimeters that will operate at 100 mK inside a sophisticated cryostat. A set of thin filters, highly transparent to X-rays, will be m…

ROSAT PSPC/HRI observations of the open cluster NGC 2422

We present the results of a ROSAT study of NGC 2422, a southern open cluster at a distance of about 470 pc, with an age close to the Pleiades. Source detection was performed on two observations, a 10-ks PSPC and a 40-ks HRI pointing, with a detection algorithm based on wavelet transforms, particularly suited to detecting faint sources in crowded fields. We have detected 78 sources, 13 of which were detected only with the HRI, and 37 detected only with the PSPC. For each source, we have computed the 0.2-2.0 keV X-ray flux. Using optical data from the literature and our own low-dispersion spectroscopic observations, we find candidate optical counterparts for 62 X-ray sources, with more than 8…

X-ray emission from young brown dwarfs in the Orion Nebula Cluster

We use the sensitive X-ray data from the Chandra Orion Ultradeep Project (COUP) to study the X-ray properties of 34 spectroscopically-identified brown dwarfs with near-infrared spectral types between M6 and M9 in the core of the Orion Nebula Cluster. Nine of the 34 objects are clearly detected as X-ray sources. The apparently low detection rate is in many cases related to the substantial extinction of these brown dwarfs; considering only the BDs with $A_V \leq 5$ mag, nearly half of the objects (7 out of 16) are detected in X-rays. Our 10-day long X-ray lightcurves of these objects exhibit strong variability, including numerous flares. While one of the objects was only detected during a sho…

ChandraX‐Ray Observation of the Orion Nebula Cluster. II. Relationship between X‐Ray Activity Indicators and Stellar Parameters

Using the results of our first paper on the Chandra HRC observation of the Orion Nebula Cluster (ONC), here we explore the relation between the coronal activity of its 1-Myr-old pre-main sequence population and stellar parameters. We find that median X-ray luminosities of low mass stars (M/M_sun &lt; 3) increase with increasing mass and decreasing stellar age. Brown dwarfs (0.03 &lt; M/M_sun &lt; 0.08) follow the same trend with mass. From M~0.1 to M~0.5M_sun, median L_X/L_bol values increase by about half an order of magnitude and then remain constant at ~10^-3.5 for the mass range from 0.5 to 3.0 M/M_sun. In these same two mass ranges, L_X/L_bol remains roughly constant with age, until it…

Res acta e potere magistratuale di interrompere una legis actio irregolare

l'articolo concerne la ricostruzione della nozione di res acta nelle legis actiones e del connesso problema dell'individuazione del momento a partire dal quale si verificavano gli effetti preclusivi nelle legis actiones. La ricerca è inoltre utile a rispondere positivamente alla domanda se il magistrato giusdicente potesse fermare in iure una legis actio caratterizzata da errori o omissioni da parte dell'attore sancendo, in questo modo, contro di lui la perdita della lite

Spatial distribution of X-ray emitting ejecta in Tychos SNR: indications of shocked Titanium

Young supernova remnants show a characteristic ejecta-dominated X-ray emission that allows us to probe the products of the explosive nucleosynthesis processes and to ascertain important information about the physics of the supernova explosions. Hard X-ray observations have recently revealed the radioactive decay lines of 44Ti at ~67.9 keV and ~78.4 keV in the Tycho's SNR. We here analyze the set of XMM-Newton archive observations of the Tycho's SNR. We produce equivalent width maps of the Fe K and Ca XIX emission lines and find indications for a stratification of the abundances of these elements and significant anisotropies. We then perform a spatially resolved spectral analysis by identify…

Il mos e la consuetudo nel De moribus di Marco Terenzio Varrone (in margine a Macr. Sat. 3.8.8-12 e Serv. Ad Aen. 7.601)

Mores and consuetudo are two terms that in the legal language of the republican age indicate teo species of customary law. The paper is aimed at investigating the meanings of mos and consuetudo in to two passages of Varro's De moribus.

X-ray emission in protostellar jets: comparison between model predictions and observations

Studi sulle liti di libertà nel diritto romano

Il lavoro è diviso in tre capitoli. Nel primo capitolo si adducono argomenti capaci di provare la risalenza delle liti di libertà - e delle regole speciali che le ispirano - all'età decemvirale. Inoltre si analizza il 'processo di Virginia' e si cercano di risolvere le antinomie e le aporie presenti nel racconto di Livio, mediante l'utilizzo di una fonte ignorata fin ora: l'Archeologia Romana di Dionigi di Alicarnasso. Nel secondo capitolo, una volta identificato il processo di Virginia con una lite di libertà, si utilizza il prezioso episodio per ricostruire alcuni tratti caratteristici delle liti di libertà nelle legis actiones: in particolare, il carattere solo eventuale dell'in ius voca…

XMM-Newton survey of two upper Scorpius regions

We study X-ray emission from young stars by analyzing deep XMM-Newton observations of two regions of the Upper Scorpius association, having an age of 5 Myr. Based on near infrared and optical photometry we identify 22 Upper Scorpius photometric members among the 224 detected X-ray sources. We derive coronal properties of Upper Scorpius stars by performing X-ray spectral and timing analysis. The study of four strong and isolated stellar flares allows us to derive the length of the flaring loops. Among the 22 Upper Scorpius stars, 13 are identified as Upper Scorpius photometric members for the first time. The sample includes 7 weak-line T Tauri stars and 1 classical T Tauri star, while the na…

Monitoring the stability of thin and medium back-up filters of the Newton-XMM EPIC camera

We are conducting a measurement program on back-up filters of the XMM-Newton EPIC camera aimed at monitoring possible aging effects during the mission lifetime. One thin and one medium EPIC back-up filters have been stored since 1997 in an environment similar to that one of the flight filters (dry nitrogen box before launch, high vacuum after launch). The transmission of the two filters has been measured periodically in the 1900-10000 angstrom wavelength range where effects of aging would be clearly evident. The preliminary results, after 5 years of monitoring, show that a slight aging effect has occurred on both filters which, however, has no significant impact onto the EPIC calibration fo…

Deep X-ray survey of the young open cluster NGC 2516 with XMM-Newton

We report on a deep X-ray survey of the young (~ 140 Myr), rich open cluster NGC 2516 obtained with the EPIC camera on board the XMM-Newton satellite. By combining data from six observations, a high sensitivity, greater than a factor 5 with respect to recent Chandra observations, has been achieved. We detected 431 X-ray sources and 234 of them have as optical counterparts cluster stars spanning the entire NGC 2516 Main Sequence. The X-ray luminosities of cluster stars span the range log Lx (erg/s) = 28.4 - 30.8. The representative temperatures span the 0.3 - 0.6 keV (3.5 - 8 MK) range for the cool component and 1.0 - 2.0 keV (12 -- 23 MK) for the hot one; similar values are found in other y…

Un'ipotesi sulla revoca della donazione per ingratitudine del liberto

The paper deals with the reasons that led Emperor Philip the Arab to introduce the gift revocation, due to the ingratitude of the Freedman. According to the Author, the reform depended on the desire to remedy the iniquity that could come from the revocatio in servitutem due to the ingratitude of the Freedman, arranged by the reform of Commodus, known through a Modestinus fragment (Mod. lib. sing. de manum. 25.3.6.1). According to the said reform – that could apply in similar cases, as happens in Paul. 11 ad ed. D. 4.2.21 pr. – the ungrateful Freedman was assigned by the judge as a slave to an emptor, who paid the price of the slave to the patronus. The new dominus would also have bought the…

Mass Segregation in the Open Cluster NGC 2422

UBVRI photometry of the open cluster NGC2422 (age ~10 8  yr) down to a limiting magnitude V ≃ 19 is used to study the cluster spatial distribution and the luminosity and mass functions. From the Color-Magnitude Diagram (CMD), we obtained a list of candidate cluster members based on a photometric criterion. Using a comparison field region and an iterative procedure, a correction for contaminating field stars has been inferred in order to obtain the luminosity and the mass functions in the M=0.4 -3.5 M ⊙ range. By analyzing the spatial distribution, we infer that a non-negligible number of cluster stars lie outside our investigated region. We estimate a correction to the mass function of the …

Simultaneous Kepler/K2 and XMM-Newton observations of superflares in the Pleiades

Flares are powerful events ignited by a sudden release of magnetic energy. With the aim of studying flares in the 125-Myr-old stars in the Pleiades observed simultaneously in optical and X-ray light, we obtained new XMM-Newton observations of this cluster during the observations of Kepler K2 Campaign 4. Our objective is to characterize the most powerful flares observed in both bands and to constrain the energy released in the optical and X-ray, the geometry of the loops, and their time evolution. We aim to compare our results to existing studies of flares occurring in the Sun and stars at different ages. We selected bright X-ray/optical flares occurred in 12 known members of the Pleiades fr…

The optical blocking filter for the ATHENA wide field imager: Ongoing activities towards the conceptual design

ATHENA is the L2 mission selected by ESA to pursue the science theme "Hot and Energetic Universe" (launch scheduled in 2028). One of the key instruments of ATHENA is the Wide Field Imager (WFI) which will provide imaging in the 0.1-15 keV band over a 40'x40' large field of view, together with spectrally and time-resolved photon counting. The WFI camera, based on arrays of DEPFET active pixel sensors, is also sensitive to UV/Vis photons. Optically generated electron-hole pairs may degrade the spectral resolution as well as change the energy scale by introducing a signal offset. For this reason, the use of an X-ray transparent optical blocking filter is needed to allow the observation of all …

'Denegare actionem', decretum e intercessio

Il lavoro adduce alcune fonti [D. 2.2.1.2 (Ulp. 3 ad ed.); D. 2.2.3.5 (Ulp. 3 ad ed.); Plin. Ep. 1.23.3; Iuv. Sat. 7.228] a sostegno della tesi secondo la quale la decisione magistratuale di denegare actionem si concretava in un decretum esposto all'intercessio dei magistrati dotati di par maiorve potestas ovvero dei tribuni della plebe. L'intercessio avrebbe consentito all'attore, una volta ottenuto l'annullamento della cd. denegatio actionis, di riproporre l'azione al riparo dal rischio di denegationes pretestuose. Could a plaintiff appeal to the tribuni plebis’ or to the par maiorve potestas’ intercessio against a decision of denegare actionem? The paper analyzes some sources [D. 2.2.1.2…

Time evolution of X-ray coronal activity in PMS stars; a possible relation with the evolution of accretion disks

We investigate the evolution of X-ray stellar activity from the age of the youngest known star forming regions (SFR), &lt; 1Myr, to about 100 Myr, i.e. the zero age main sequence (ZAMS) for a ~ 1M_sun star. We consider five SFR of varying age (Rho Ophiuchi, the Orion Nebula Cluster, NGC 2264, Chamaeleon I, and Eta Chamaeleontis) and two young clusters (the Pleiades and NGC 2516). Optical and X-ray data for these regions are retrieved both from archival observations and recent literature, and reanalyzed here in a consistent manner so to minimize systematic differences in the results. We study trends of L_X and L_X/L_bol as a function of stellar mass and association age. For low mass stars (M…

Gli indices nel processo criminale extra ordinem

Il contributo mira a descrivere il regime della chiamata di correo nel processo criminale extra ordinem di tipo imperiale in età classica, con un accenno al diritto del basso impero.

Bright X-Ray Flares in Orion Young Stars from COUP: Evidence for Star-Disk Magnetic Fields?

We have analyzed a number of intense X-ray flares observed in the Chandra Orion Ultradeep Project (COUP), a 13 days observation of the Orion Nebula Cluster (ONC). Analysis of the flare decay allows to determine the size, peak density and magnetic field of the flaring structure. A total of 32 events (the most powerful 1% of COUP flares), have sufficient statistics for the analysis. A broad range of decay times (from 10 to 400 ks) are present in the sample. Peak flare temperatures are often very high, with half of the flares in the sample showing temperatures in excess of 100 MK. Significant sustained heating is present in the majority of the flares. The magnetic structures which are found, a…

INTORNO A INTERPRETATIO THEODOSIANI 9.39 DE CALUMNIATORIBUS

Si tratta di un contributo volto a fornire una chiave di lettura al curioso fenomeno della mancata corrispondenza tra le definizioni di 'calumniatores' che si trovano in I.C.Th. 9.39.3 e le costituzioni inserite nel titolo 'de calumniatoribus' del Codice Teodosiano. Tali definizioni corrispondono non alle costituzioni del titolo, ma alle nozioni di calumniator rinvenibii nelle costituzioni del Teodosiano accolte dal Breviarium Alaricianum e relative alla materia della calumnia. Anche il rinvio al ius contenuto nella chiusa può spiegarsi riferendolo ad alcuni passi di giuristi classici menzionati dalla c.d. legge delle citazioni, capaci di colmare le lacune delle interpretationes.

Le costituzioni superflue del Codice di Giustiniano, secondo Taleleo

Giustiniano, nelle costituzioni introduttive dei Digesta, del Codice e delle Istituzioni, dichiara di volere perseguire una finalità di certezza del dritto (ius certum), anche per mezzo della rimozione di leges considerate superflue o ripetitive.Tuttavia, un'indagine, mai compiuta in precedenza, sul commento di Taleleo al Codice, permette di rintracciare nel commento di questo antecessore sette giudizi di superfluità di altrettante costituzioni imperiali. Il lavoro si propone di riflettere sul modo in cui i compilatori perseguirono la finalità di creare un ius certum e sui suggerimenti pratici forniti agli studenti dei corsi degli antecessori Justinian, in the introductory constitutions of …

Lege agere pro tutela

Il lavoro propone una nuova interpretazione dell'ipotesi derogatoria ai divieti di lege agere alieno nomine coincidente con il lege agere pro tutela citato in I. 4.10. Contrariamente alle opinioni precedentemente proposte in dottrina, si dimostra come l'agere pro tutela coincidesse con l'agere del tutor ad litem nei casi di oblatio litis ovvero, anteriormente al I sec. d.C., nelle ipotesi di infantia del pupillo o di assenza del pupillo o della mulier.

Baseline design of the thermal blocking filters for the X-IFU detector on board ATHENA

ATHENA is an advanced X-ray observatory designed by a large European consortium to address the science theme "Hot and Energetic Universe" recently selected by ESA for L2 – the second Large-class mission within the Cosmic Vision science program (launch scheduled in 2028). One of the key instruments of the mission is the X-ray Integral Field Unit (X-IFU), an array of Transition Edge Sensor (TES) micro-calorimeters with high energy resolution (2.5 eV @ 6 keV) in the energy range 0.2÷12 keV, operating at the focal plane of a large effective area high angular resolution (5" HEW) grazing incidence X-ray telescope. The X-IFU operates at temperatures below 100 mK and thus requires a sophisticated c…

Nota sull'adrogatio libertorum

The author analyzes the inspiring reasons of the adrogatio libertorum classical discipline. In particular, he criticizes the idea according to which the limitations by jurists derived from the need to save the iura patronatus; furthermore, because the adrogatio libertorum could not compromise the iura patronatus, the consent of the patron was not required to perfect the act.

The complex phenomena of young stellar objects revealed by their X‐ray variability

The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase

The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer, studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory, a versatile observatory designed to address the Hot and Energetic Universe science theme, selected in November 2013 by the Survey Science Committee. Based on a large format array of Transition Edge Sensors (TES), it aims to provide spatially resolved X-ray spectroscopy, with a spectral resolution of 2.5 eV (up to 7 keV) over an hexagonal field of view of 5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement Review (SRR) in June 2022, at about the same time when ESA called for an overall X-IFU redesign (i…

Sul rapporto tra il katà pòdas e le traduzioni letterali di Taleleo dei rescritti in latino del Codex

Il contributo è volto a dimostrare che la scelta dell'antecessore Taleleo di interrompere la traduzione in greco dei rescritti latini del Codex per affidarsi al katà pòdas anonimo al fine della loro traduzione è dipesa non già da una scelta metodologica, ma dal poco tempo a disposizione per la redazione del commentario al Codex.

Herbig-Haro objects: model prediction and comparison with X-ray and optical observations

Simultaneous Kepler/K2 and XMM‐Newton observations of superflares in the Pleiades

Proceeding of a contributed talk given at the meeting: "TIME-DOMAIN ASTRONOMY: A HIGH ENERGY VIEW" held at ESAC, Madrid, 13 - 15 JUNE 2018 Together with coronal mass ejection, flares are the most energetic stellar magnetic events, ignited by a sudden release of magnetic energy, which triggers a cascade of interconnected phenomena, each resulting in emission in different bands. For this reason, flares are intrinsic multiwavelength phenomena. In particular, optical and soft X-ray emission probes two different events occurring during flares: the heating of plasma in the upper photosphere at the footpoints of the magnetic loops and the heating and cooling of the plasma confined in the loops in …

High‐Resolution X‐Ray Spectroscopy of the Post–T Tauri Star PZ Telescopii

We present an analysis of the Chandra High Energy Transmission Grating Spectrometer observation of the rapidly rotating P_(rot)=0.94 d post T Tauri (~20 Myr old) star PZ Telescopii, in the Tucana association. Using two different methods we have derived the coronal emission measure distribution, em(T), and chemical abundances. The em(T) peaks at log T = 6.9 and exhibits a significant emission measure at temperatures log T > 7. The coronal abundances are generally ~0.5 times the solar photospheric values that are presumed fairly representative of the composition of the underlying star. A minimum in abundance is seen at a first ionization potential (FIP) of 7-8 eV, with evidence for higher abu…

The ATHENA X-ray Integral Field Unit (X-IFU)

Event: SPIE Astronomical Telescopes + Instrumentation, 2018, Austin, Texas, United States.

Recensione di M. Indra, Status quaestio. Studien zum Freiheisprozess im klassischen roemischen Recht, Berlin 2011, 1-314

la recensione è volta a dare conto - in modo critico - del contenuto del saggio di Miriam