OA@INAF - Istituto Nazionale di Astrofisica
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Gli incunaboli e le cinquecentine degli Osservatori astronomici dell'Istituto Nazionale di Astrofisica 1478-1560
Full text linkL’Istituto Nazionale di Astrofisica (INAF) nasce nel 1999 dalla fusione dei dodici Osservatori Astronomici e Astrofisici distribuiti sul territorio nazionale, ereditandone il prezioso patrimonio bibliografico, archivistico e strumentale, in alcuni casi antico di circa tre secoli. Il censimento dei libri a stampa del XV e XVI secolo, conservati nelle varie sedi dell’Ente, ha reso possibile la realizzazione del presente catalogo costituito da 227 edizioni, comprendenti incunaboli e cinquecentine pubblicati tra il 1478 e il 1560. Il volume, oltre a essere un repertorio bibliografico specialistico, rappresenta una raccolta di testi scientifici unica nel panorama mondiale delle collezioni librarie antiche dedicate al tema delle Scienze del Cielo. Attraverso l’analisi dei contenuti delle edizioni e delle peculiarità degli esemplari descritti, il catalogo offre svariate chiavi di lettura che possono consentire l’approfondimento di tematiche disciplinari differenti: si parte dall’evoluzione della storia dell’astronomia e delle scienze ad essa affini per giungere alla delineazione della storia della tipografia italiana ed europea in ambito scientifico e alla ricostruzione del pubblico di lettori e possessori che si sono materialmente serviti di tali esemplari per lo studio e la diffusione dell’astronomia.Prefazione di Marco Tavani. Introduzioni di Edoardo Barbieri e Fabrizio Bònol
The GAPS Programme at TNG. XXX: Characterization of the low-density gas giant HAT-P-67 b with GIARPS
Full text linkHAT-P-67 b is one of the lowest-density gas giants known to date, making it
an excellent target for atmospheric characterization through the transmission
spectroscopy technique. In the framework of the GAPS large programme, we
collected four transit events, with the aim of studying the exoplanet
atmosphere and deriving the orbital projected obliquity. We exploited the
high-precision GIARPS observing mode of the TNG, along with additional archival
TESS photometry, to explore the activity level of the host star. We performed
transmission spectroscopy, both in the VIS and in the nIR wavelength range, and
analysed the RML effect both fitting the RVs and the Doppler shadow. Based on
the TESS photometry, we redetermined the transit parameters of HAT-P-67 b. By
modelling the RML effect, we derived a sky-projected obliquity of
(){\deg} indicating an aligned planetary orbit. The chromospheric
activity index , the CCF profile, and the
variability in the transmission spectrum of the H line suggest that the
host star shows signatures of stellar activity and/or pulsations. We found no
evidence of atomic or molecular species in the VIS transmission spectra, with
the exception of pseudo-signals corresponding to Cr I, Fe I, H, Na I,
and Ti I. In the nIR range, we found an absorption signal of the He I triplet
of 5.56%(19.0), corresponding to an effective
planetary radius of 3 (where 2) which extends beyond
the planet's Roche Lobe radius. Owing to the stellar variability, together with
the high uncertainty of the model, we could not confirm the planetary origin of
the signals found in the optical transmission spectrum. On the other hand, we
confirmed previous detections of the infrared He I triplet, providing a
19.0 detection. Our finding indicates that the planet's atmosphere is
evaporating
EUSO-Offline: a comprehensive simulation and analysis framework
Full text linkThe complexity of modern cosmic ray observatories and the rich data sets they capture often require a sophisticated software framework to support the simulation of physical processes, detector response, as well as reconstruction and analysis of real and simulated data. Here we present the EUSO-Offline framework. The code base was originally developed by the Pierre Auger Collaboration, and portions of it have been adopted by other collaborations to suit their needs. We have extended this software to fulfill the requirements of Ultra-High Energy Cosmic Ray detectors and very high energy neutrino detectors developed for the Joint Exploratory Missions for an Extreme Universe Observatory (JEM-EUSO). These path-finder instruments constitute a program to chart the path to a future space-based mission like POEMMA. For completeness, we describe the overall structure of the framework developed by the Auger collaboration and continue with a description of the JEM-EUSO simulation and reconstruction capabilities. The framework is written predominantly in modern C++ (compliled against C++17) and incorporates third-party libraries chosen based on functionality and our best judgment regarding support and longevity. Modularity is a central notion in the framework design, a requirement for large collaborations in which many individuals contribute to a common code base and often want to compare different approaches to a given problem. For the same reason, the framework is designed to be highly configurable, which allows us to contend with a variety of JEM-EUSO missions and observation scenarios. We also discuss how we incorporate broad, industry-standard testing coverage which is necessary to ensure quality and maintainability of a relatively large code base, and the tools we employ to support a multitude of computing platforms and enable fast, reliable installation of external packages. Finally, we provide a few examples of simulation and reconstruction applications using EUSO-Offline
Cosmology and fundamental physics with the ELT-ANDES spectrograph
Full text linkState-of-the-art 19th century spectroscopy led to the discovery of quantum mechanics, and 20th century spectroscopy led to the confirmation of quantum electrodynamics. State-of-the-art 21st century astrophysical spectrographs, especially ANDES at ESO's ELT, have another opportunity to play a key role in the search for, and characterization of, the new physics which is known to be out there, waiting to be discovered. We rely on detailed simulations and forecast techniques to discuss four important examples of this point: big bang nucleosynthesis, the evolution of the cosmic microwave background temperature, tests of the universality of physical laws, and a real-time model-independent mapping of the expansion history of the universe (also known as the redshift drift). The last two are among the flagship science drivers for the ELT. We also highlight what is required for the ESO community to be able to play a meaningful role in 2030s fundamental cosmology and show that, even if ANDES only provides null results, such `minimum guaranteed science' will be in the form of constraints on key cosmological paradigms: these are independent from, and can be competitive with, those obtained from traditional cosmological probes
The Seeding of Cosmic Ray Electrons by Cluster Radio Galaxies: A Review
No full textRadio galaxies in clusters of galaxies are a prominent reservoir of magnetic fields and of non-thermal particles, which become mixed with the intracluster medium. We review the observational and theoretical knowledge of the role of these crucial ingredients for the formation of diffuse radio emission in clusters (radio halos, relics, mini halos) and outline the open questions in this field
JWST/MIRI Detection of Suprathermal OH Rotational Emissions: Probing the Dissociation of the Water by Lyα Photons near the Protostar HOPS 370
No full textUsing the MIRI medium-resolution spectrometer on JWST, we have detected pure rotational, suprathermal OH emissions from the vicinity of the intermediate-mass protostar HOPS 370 (OMC2/FIR3). These emissions are observed from shocked knots in a jet/outflow and originate in states of rotational quantum number as high as 46 that possess excitation energies as large as E U /k = 4.65 × 104 K. The relative strengths of the observed OH lines provide a powerful diagnostic of the ultraviolet radiation field in a heavily extinguished region (A V ∼ 10–20) where direct UV observations are impossible. To high precision, the OH line strengths are consistent with a picture in which the suprathermal OH states are populated following the photodissociation of water in its band by ultraviolet radiation produced by fast (∼80 km s‑1) shocks along the jet. The observed dominance of emission from symmetric ( ) OH states over that from antisymmetric (A″) states provides a distinctive signature of this particular population mechanism. Moreover, the variation of intensity with rotational quantum number suggests specifically that Lyα radiation is responsible for the photodissociation of water, an alternative model with photodissociation by a 104 K blackbody being disfavored at a high level of significance. Using measurements of the Brα flux to estimate the Lyα production rate, we find that ∼4% of the Lyα photons are absorbed by water. Combined with direct measurements of water emissions in the ν 2 = 1 ‑ 0 band, the OH observations promise to provide key constraints on future models for the diffusion of Lyα photons in the vicinity of a shock front
The GRAVITY young stellar object survey: XIII. Tracing the time-variable asymmetric disk structure in the inner AU of the Herbig star HD 98922
No full textContext. Temporal variability in the photometric and spectroscopic properties of protoplanetary disks is common in young stellar objects. However, evidence pointing toward changes in their morphology over short timescales has only been found for a few sources, mainly due to a lack of high-cadence observations at high angular resolution. Understanding this type of variation could be important for our understanding of phenomena related to disk evolution. Aims. We study the morphological variability of the innermost circumstellar environment of HD 98922, focusing on its dust and gas content. Methods. Multi-epoch observations of HD 98922 at milliarcsecond resolution with VLTI/GRAVITY in the K-band at low (R = 20) and high (R = 4000) spectral resolution are combined with VLTI/PIONIER archival data covering a total time span of 11 yr. We interpret the interferometric visibilities and spectral energy distribution with geometrical models and through radiative transfer techniques using the code MCMax. We investigated high-spectral-resolution quantities (visibilities and differential phases) to obtain information on the properties of the HI Brackett-γ (Brγ)-line-emitting region. Results. Comparing observations taken with similar (u,v) plane coverage, we find that the squared visibilities do not vary significantly, whereas we find strong variability in the closure phases, suggesting temporal variations in the asymmetric brightness distribution associated to the disk. Our observations are best fitted by a model of a crescent-like asymmetric dust feature located at ~1 au and accounting for ~70 % of the near-infrared (NIR) emission. The feature has an almost constant magnitude and orbits the central star with a possible sub-Keplerian period of ~12 months, although a 9 month period is another, albeit less probable, solution. The radiative transfer models show that the emission originates from a small amount of carbon-rich (25%) silicates, or quantum-heated particles located in a low-density region. Among different possible scenarios, we favor hydrodynamical instabilities in the inner disk that can create a large vortex. The high spectral resolution differential phases in the Brγ line show that the hot-gas compact component is offset from the star and in some cases is located between the star and the crescent feature. The scale of the emission does not favor magnetospheric accretion as a driving mechanism. The scenario of an asymmetric disk wind or a massive accreting substellar or planetary companion is discussed. Conclusions. With this unique observational data set for HD 98922, we reveal morphological variability in the innermost 2 au of its disk region. This property is possibly common to many other protoplanetary disks, but is not commonly observed due to a lack of high-cadence observation. It is therefore important to pursue this approach with other sources for which an extended dataset with PIONIER, GRAVITY, and possibly MATISSE is available
First spectropolarimetric observation of the neutron star low-mass X-ray binary GX 3+1
No full textWe report the first simultaneous X-ray spectropolarimetric observation of the bright atoll neutron star low-mass X-ray binary GX 3+1, performed by the Imaging X-ray Polarimetry Explorer (IXPE) joint with NICER and NuSTAR. The source does not exhibit significant polarization in the 2–8 keV energy band, with an upper limit of 1.3% at a 99% confidence level on the polarization degree. The observed spectra can be well described by a combination of thermal disk emission, the hard Comptonization component, and reflected photons off the accretion disk. In particular, from the broad Fe Kα line profile, we were able to determine the inclination of the system (i ≈ 36°), which is crucial for comparing the observed polarization with theoretical models. Both the spectral and polarization properties of GX 3+1 are consistent with those of other atoll sources observed by IXPE. Therefore, we may expect a similar geometrical configuration for the accreting system and the hot Comptonizing region. The low polarization is also consistent with the low inclination of the system
The GRAVITY young stellar object survey XII. The hot gas disk component in Herbig Ae/Be stars
No full textContext. The region of protoplanetary disks closest to a star (within 1–2 au) is shaped by a number of different processes, from accretion of the disk material onto the central star to ejection in the form of winds and jets. Optical and near-IR emission lines are potentially good tracers of inner disk processes if very high spatial and/or spectral resolution are achieved. Aims. In this paper, we exploit the capabilities of the VLTI-GRAVITY near-IR interferometer to determine the location and kinematics of the hydrogen emission line Brγ. Methods. We present VLTI-GRAVITY observations of the Brγ line for a sample of 26 stars of intermediate mass (HAEBE), the largest sample so far analysed with near-IR interferometry. Results. The Brγ line was detected in 17 objects. The emission is very compact (in most cases only marginally resolved), with a size of 10–30 R∗(1–5 mas). About half of the total flux comes from even smaller regions, which are unresolved in our data. For eight objects, it was possible to determine the position angle (PA) of the line-emitting region, which is generally in agreement with that of the inner-dusty disk emitting the K-band continuum. The position-velocity pattern of the Brγ line-emitting region of the sampled objects is roughly consistent with Keplerian rotation. The exception is HD 45677, which shows more extended emission and more complex kinematics. The most likely scenario for the Brγ origin is that the emission comes from an MHD wind launched very close to the central star, in a region well within the dust sublimation radius. An origin in the bound gas layer at the disk surface cannot be ruled out, while accreting matter provides only a minor fraction of the total flux. Conclusions. These results show the potential of near-IR spectro-interferometry to study line emission in young stellar objects