EEG-Based Empathic Safe Cobot

An empathic collaborative robot (cobot) was realized through the transmission of fear from a human agent to a robot agent. Such empathy was induced through an electroencephalographic (EEG) sensor worn by the human agent, thus realizing an empathic safe brain-computer interface (BCI). The empathic safe cobot reacts to the fear and in turn transmits it to the human agent, forming a social circle of empathy and safety. A first randomized, controlled experiment involved two groups of 50 healthy subjects (100 total subjects) to measure the EEG signal in the presence or absence of a frightening event. The second randomized, controlled experiment on two groups of 50 different healthy subjects (100 total subjects) exposed the subjects to comfortable and uncomfortable movements of a collaborative robot (cobot) while the subjects’ EEG signal was acquired. The result was that a spike in the subject’s EEG signal was observed in the presence of uncomfortable movement. The questionnaires were distributed to the subjects, and confirmed the results of the EEG signal measurement. In a controlled laboratory setting, all experiments were found to be statistically significant. In the first experiment, the peak EEG signal measured just after the activating event was greater than the resting EEG signal (p < 10−3). In the second experiment, the peak EEG signal measured just after the uncomfortable movement of the cobot was greater than the EEG signal measured under conditions of comfortable movement of the cobot (p < 10−3). In conclusion, within the isolated and constrained experimental environment, the results were satisfactory

Large Binocular Telescope observations of PSR J2043+2740

We present the results of deep optical imaging of the radio/$\gamma$-ray pulsar PSR J2043+2740, obtained with the Large Binocular Telescope (LBT). With a characteristic age of 1.2 Myr, PSR J2043+2740 is one of the oldest (non recycled) pulsars detected in $\gamma$-rays, although with still a quite high rotational energy reservoir ($\dot{E}_{\rm rot} = 5.6 \times 10^{34}$ erg s$^{-1}$). The presumably close distance (a few hundred pc), suggested by the hydrogen column density ($N_{\rm H} \lesssim 3.6 \times 10^{20}$ cm$^{-2}$), would make it a viable target for deep optical observations, never attempted until now. We observed the pulsar with the Large Binocular Camera of the LBT. The only object (V=25.44$\pm$0.05) detected within ~3" from the pulsar radio coordinates is unrelated to it. PSR J2043+2740 is, thus, undetected down to V~26.6 (3-$\sigma$), the deepest limit on its optical emission. We discuss the implications of this result on the pulsar emission properties.Comment: 4 pages, 3 figures, accepted for publication on MNRA

Subsurface structure of the Solfatara volcano (Campi Flegreicaldera, Italy) as deduced from joint seismic-noise array,volcanological and morphostructural analysis

The joint application of different seismological techniques for seismic noise analysis, and the results of a volcanological and morphostructural survey, have allowed us to obtain a detailed and well constrained image of the shallow crustal structure of the Solfatara volcano (Campi Flegrei caldera, Italy). Horizontal-to-vertical spectral ratios, inversion of surface wave dispersion curves and polarization analysis provided resonance frequencies and peak amplitudes, shear wave velocity profiles and polarization pattern of coherent ambient noise. These results, combined in a unique framework, indicate that the volcanic edifice is characterized by lateral and vertical discontinuities and heterogeneities in terms of shear wave velocity, lithological contrasts and structural setting. The interpretation of the seismological results, with the volcanological and morphostructural constraints, supports the hypothesis that the volcano has been characterized by a complex and intense activity, with the alternation of constructive and destructive phases, during which magmatic and phreatomagmatic explosions built a complex tuff-cone, later reworked by atmospheric agents and altered by hydrothermal activity. The differences in the velocity structure between the central and eastern parts of the crater have been interpreted as resulting from a possible eastward migration of the eruptive vent along the deformational features affecting the area, and to the presence of viscous lava and lithified tuff bodies within the feeding conduits, which are buried under a covering of reworked materials of variable thickness. The observed fault and fracture systems, partially inherited from regional structural setting and exhumed during volcanism and ground deformation episodes also seems to strongly control wave propagation, affecting the noise polarization properties

Acquisizione di rumore sismico nell'Appennino Reggiano Modenese 11-15 aprile 2006

Tra l’11 e il 15 aprile 2006 è stata condotta una campagna di acquisizione di rumore sismico in alcuni siti in frana dell’Appennino Settentrionale. Lo scopo dell’esperimento è quello di stimare gli effetti di sito su corpi franosi tipici dell’Appennino Modenese e Reggiano, nonché di studiare il comportamento delle frane quando sono soggette ad eventi sismici. Le registrazioni di rumore sono state effettuate con stazioni equipaggiate con sensori a corto periodo a tre componenti. Per la stima dell’amplificazione locale è stata scelta una serie di siti caratterizzati da litologie diverse. Inoltre, in siti omogenei e ben studiati dal punto di vista strutturale, sono state effettuate delle misure di rumore in configurazione di array per la stima di un modello di velocità superficiale, allo scopo di confrontare i risultati sperimentali con le funzioni di trasferimento teoriche. La durata delle registrazione non è stata inferiore ad un’ora per ogni sito. Le misure sono state effettuate sulle frane di Ca’ Lita (MO), Cavola (RE) e La Lezza Nuova (RE). Tutte e tre sono frane da colata, caratterizzate dalla presenza in superficie di strati di argille, e sono state studiate dal punto di vista strutturale, tra l’altro attraverso pozzi di sondaggio ed esperimenti di sismica attiva

The StEllar Counterparts of COmpact high velocity clouds (SECCO) survey. I. Photos of ghosts

We present an imaging survey aimed at searching for the stellar counterparts of recently discovered ultra-compact high-velocity HI clouds (UCHVC). Adams et al. (2013) proposed these clouds to be candidate mini-haloes in the Local Group and/or its surroundings, within a distance range of 0.25-2.0 Mpc. Using the Large Binocular Telescope we obtain wide-field (~ 23' X 23') g- and r-band images of the twenty-five most promising and most compact clouds among the fifty-nine identified by Adams et al. Careful visual inspection of all the images does not reveal any stellar counterpart even slightly resembling LeoP, the only local dwarf galaxy that was found as a counterpart to a previously detected high velocity cloud. Only a possible distant (D>3.0 Mpc) counterpart to HVC274.68+74.70-123 has been identified on our images. The point source photometry in the central 17.3' X 7.7' chips reaches r<= 26.5, and is expected to contain most of the stellar counterparts to the UCHVCs. However, no obvious stellar over-density is detected in any of our fields, in marked contrast to our comparison LeoP field in which the dwarf galaxy is detected at a >30 sigma significance level. Only HVC352.45+59.06+263 may be associated with a weak over-density, whose nature cannot be ascertained with our data. Sensitivity tests shows that our survey would have detected any dwarf galaxy dominated by an old stellar population, with an integrated absolute magnitude M_V<= -8.0, a half-light radius r_h<= 300 pc, and lying within 1.5 Mpc from us, thereby confirming that it is unlikely that the observed UCHVCs are associated with stellar counterparts typical of known Local Group dwarf galaxies.Comment: Accepted for publication by A&A. PdfLaTex. 24 pages, 27 figures. Minor changes; A&A language editin

The contribution of faint AGNs to the ionizing background at z~4

Finding the sources responsible for the hydrogen reionization is one of the most pressing issues in cosmology. Bright QSOs are known to ionize their surrounding neighborhood, but they are too few to ensure the required HI ionizing background. A significant contribution by faint AGNs, however, could solve the problem, as recently advocated on the basis of a relatively large space density of faint active nuclei at z>4. We have carried out an exploratory spectroscopic program to measure the HI ionizing emission of 16 faint AGNs spanning a broad U-I color interval, with I~21-23 and 3.6<z<4.2. These AGNs are three magnitudes fainter than the typical SDSS QSOs (M1450<~-26) which are known to ionize their surrounding IGM at z>~4. The LyC escape fraction has been detected with S/N ratio of ~10-120 and is between 44 and 100% for all the observed faint AGNs, with a mean value of 74% at 3.6<z<4.2 and -25.1<M1450<-23.3, in agreement with the value found in the literature for much brighter QSOs (M1450<~-26) at the same redshifts. The LyC escape fraction of our faint AGNs does not show any dependence on the absolute luminosities or on the observed U-I colors. Assuming that the LyC escape fraction remains close to ~75% down to M1450~-18, we find that the AGN population can provide between 16 and 73% (depending on the adopted luminosity function) of the whole ionizing UV background at z~4, measured through the Lyman forest. This contribution increases to 25-100% if other determinations of the ionizing UV background are adopted. Extrapolating these results to z~5-7, there are possible indications that bright QSOs and faint AGNs can provide a significant contribution to the reionization of the Universe, if their space density is high at M1450~-23.Comment: Accepted for publication on A&A, 16 pages, 22 figure

The VMC Survey. XXXII. Pre-main-sequence populations in the Large Magellanic Cloud

Context Detailed studies of intermediate- and low-mass pre-main-sequence (PMS) stars outside the Galaxy have so far been conducted only for small targeted regions harbouring known star formation complexes. The VISTA Survey of the Magellanic Clouds (VMC) provides an opportunity to study PMS populations down to solar masses on a galaxy-wide scale. Aims Our goal is to use near-infrared data from the VMC survey to identify and characterise PMS populations down to ∼ 1 M� across the Magellanic Clouds. We present our colour−magnitude diagram method, and apply it to a ∼ 1.5 deg2 pilot field located in the Large Magellanic Cloud. Methods The pilot field is divided into equal-size grid elements. We compare the stellar population in every element with the population in nearby control fields by creating Ks/(Y−Ks) Hess diagrams; the observed density excesses over the local field population are used to classify the stellar populations. Results Our analysis recovers all known star formation complexes in this pilot field (N 44, N 51, N 148, and N 138) and for the first time reveals their true spatial extent. In total, around 2260 PMS candidates with ages . 10 Myr are found in the pilot field. PMS structures, identified as areas with a significant density excess of PMS candidates, display a power-law distribution of the number of members with a slope of −0.86 ± 0.12. We find a clustering of the young stellar populations along ridges and filaments where dust emission in the far-infrared (FIR) (70 µm – 500 µm) is bright. Regions with young populations lacking massive stars show a lower degree of clustering and are usually located in the outskirts of the star formation complexes. At short FIR wavelengths (70 µm, 100 µm) we report a strong dust emission increase in regions hosting young massive stars, which is less pronounced in regions populated only by less massive (. 4 M�) PMS stars

Three Small Planets Transiting a Hyades Star

We present the discovery of three small planets transiting K2-136 (LP 358 348, EPIC 247589423), a late K dwarf in the Hyades. The planets have orbital periods of $7.9757 \pm 0.0011$, $17.30681^{+0.00034}_{-0.00036}$, and $25.5715^{+0.0038}_{-0.0040}$ days, and radii of $1.05 \pm 0.16$, $3.14 \pm 0.36$, and $1.55^{+0.24}_{-0.21}$ $R_\oplus$, respectively. With an age of 600-800 Myr, these planets are some of the smallest and youngest transiting planets known. Due to the relatively bright (J=9.1) host star, the planets are compelling targets for future characterization via radial velocity mass measurements and transmission spectroscopy. As the first known star with multiple transiting planets in a cluster, the system should be helpful for testing theories of planet formation and migration.Comment: Accepted to The Astronomical Journa

An X-ray fading, UV brightening QSO at z ≈ 6

Explaining the existence of super massive black holes (SMBHs) with MBH≳ 108 M· at z≳ 6 is a persistent challenge to modern astrophysics. Multiwavelength observations of z≳ 6 quasi-stellar objects (QSOs) reveal that, on average, their accretion physics is similar to that of their counterparts at lower redshift. However, QSOs showing properties that deviate from the general behavior can provide useful insights into the physical processes responsible for the rapid growth of SMBHs in the early universe. We present X-ray (XMM-Newton, 100 ks) follow-up observations of a z doublesim 6 QSO, J1641+3755, which was found to be remarkably X-ray bright in a 2018 Chandra dataset. J1641+3755 is not detected in the 2021 XMM-Newton observation, implying that its X-ray flux decreased by a factor 3;7 on a notably short timescale (i.e., doublesim 115 rest-frame days), making it the z &gt; 4 QSO with the largest variability amplitude. We also obtained rest-frame ultraviolet (UV) spectroscopic and photometric data with the Large Binocular Telescope (LBT). Surprisingly, comparing our LBT photometry with archival data, we found that J1641+3755 became consistently brighter in the rest-frame UV band from 2003 to 2016, while no strong variation occurred from 2016 to 2021. Its rest-frame UV spectrum is consistent with the average spectrum of high-redshift QSOs. Multiple narrow absorption features are present, and several of them can be associated with an intervening system at z = 5.67. Several physical causes can explain the variability properties of J1641+3755, including intrinsic variations of the accretion rate, a small-scale obscuration event, gravitational lensing due to an intervening object, and an unrelated X-ray transient in a foreground galaxy in 2018. Accounting for all of the z &gt; 6 QSOs with multiple X-ray observations separated by more that ten rest-frame days, we found an enhancement of strongly (i.e., by a factor &gt; 3) X-ray variable objects compared to QSOs at later cosmic times. This finding may be related to the physics of fast accretion in high-redshift QSOs