Browsing by Type "Conference abstract"

We use thermal-infrared spectra returned by the Mars Express Planetary Fourier Spectrometer (PFS-MEx) to retrieve atmospheric and surface temperature, and dust and water ice aerosol optical depth. More than 2,500,000 spectra have been used to build this new dataset, covering the full range of season, latitude, longitude, and local time. The data presented here span more than six Martian years (from MY26, Ls = 331°, 10 January 2004 to MY 33, Ls = 78°, 6 December 2015). We successfully retrieved atmospheric temperatures and aerosols opacity in the polar regions, including the polar nights. By exploiting PFS/MEx capability to perform observations at different local times (LT), this dataset allows investigation of the daily cycles of suspended dust and ice. We present an overview of the seasonal and latitudinal dependence of atmospheric quantities during the relevant period, as well as an assessment of the interannual variability in the current Martian climate, including spatial, daily (LT), seasonal, and interannual variations of the aphelion equatorial cloud belt. With unprecedented spatial and temporal coverage and details revealed, this dataset offers new challenges to the GCMs and, at the same time, a new reference for the MYs complementary to those observed by MGS-TES.

The Rosetta space mission investigated comet 67P/Churyumov-Gerasimenko (67P) over two years from August 2014 to September 2016. Onboard the spacecraft, the ROSINA experiment included two mass spectrometers to derive the composition of neutrals and ions, and a COmet Pressure Sensor (COPS) to monitor the density and velocity of the neutrals in the coma. We will here analyse and discuss data from the Reflectron-type Time-Of-Flight instrument during the comet escort phase. The RTOF mass spectrometer possessed a wide mass range and a high temporal resolution (Balsiger et al., 2007). The analysis of 67P/C-G's coma major molecules over the mission showed strong variability of the comet coma's main volatiles concentrations (H2O, CO2, CO) and their relative abundances. The 2 years long Rosetta mission allowed us to observe the seasonal evolution in the atmosphere of 67P, in particular the change occurring during the equinoxes and at perihelion. In this work, we analyze the asymmetry in the outgassing rate before and after the perihelion (13/08/2015), the evolution of abundance ratios through the whole mission, and in particular the behavior of the very volatile CO molecules. Density maps projected on the surface of 67P demonstrate the evolution of the three main coma species after the outbound equinox. We will present first results of our comet nucleus thermal modelling used to simulate the internal structure and temperature evolution of 67P at characteristic surface areas. These results will be compared with the coma composition measurements obtained by ROSINA....

6.7 GHz (or class II) methanol masers have been detected exclusively toward high mass star forming regions and may be a tracer of an accretion disk around a highly embedded high mass protostar. Several studies have shown a lack of radio continuum associated with methanol maser emission, which could indicate that these masers are related to the earliest stages of high mass star formation. We recently performed a large, high sensitive (~3-10 uJy) Karl G. Jansky Very Large Array (VLA) survey to search for radio continuum emission from a sample of hot molecular cores and infrared dark cloud cores, previously undetected in the radio continuum at 1 mJy sensitivity. The morphology and spectrum of most of our radio detections are consistent with being ionized jets. As models of star formation predict that jets are collimated by accretion disks, we have selected 6 prominent examples of ionized jet candidates to study the behavior of the masers with respect to the jet and to understand the role that both disks and jets play in the process of high mass star formation. Using the VLA, we performed simultaneous observations of the radio continuum and the 6.7 GHz methanol maser, obtaining accurate relative positions between them. From the accuracy of our observations, we found that all the methanol masers detected are associated with the radio continuum from the jet. Furthermore, for some sources the maser spots show a linear distribution with a velocity gradient nearly perpendicular to the ionized jet, a further indication of emission from an accretion disk.

The Planck mission detected hundreds of extragalactic radio sources at frequencies from 28 to 857 GHz. Since Planck's calibration is absolute, based on the satellite's annual motion around the Sun, and since its beams are well-characterized at the sub-percent levels, Planck's flux density measurements are absolute to percent-level accuracy. We have made coordinated Planck, VLA and ATCA observations of ~60 strong, unresolved sources in order to compare Planck's absolute calibration to that used by these two interferometers at 22, 28 and 43 GHz. The flux densities of the sources used to calibrate the VLA observations are taken from Perley and Butler (2013), which is fundamentally based on models of the planet Mars calibrated via WMAP observations. The flux densities of the sources used to calibrate the ATCA observations are based on models of the planet Uranus. Despite the scatter introduced by the variability of many of the sources, the three flux density scales are determined to agree to 1-2% accuracy.

The relation between magnetic activity and rotation periods in late-type stars provides fundamental information on the stellar dynamo and spin evolution. In spite of its importance for stellar physics, homogeneous samples of stars with accurate and sensitive measurement of both rotation period and magnetic activity have been hard to come by. The Kepler mission represents a significant step forward, providing high-cadence optical light curves for thousands of stars, from which the rotation period can be measured observing the brightness modulation due to star spots. A cross-match of the Kepler Input Catalog with the 3XMM-DR5 Catalog and subsequent careful inspection for likely non-stellar sources yields more than 100 late-type stars. We have developed an algorithm which identifies rotation periods and white-light flares in the Kepler light curves. We have calculated the X-ray luminosity from the 3XMM-DR5 count rates, and searched the light curves provided by the EXTraS (Exploring the X-ray Transient and variable Sky) FP-7 project for X-ray flares. Here we discuss the correlation between various measures for coronal and photometric activity (from the XMM-Newton and the Kepler data, respectively) and the Kepler rotation periods and Rossby number.

A key missing element in our understanding of cosmic assembly is the nature of energetic feedback from supermassive black holes (SMHBs) and the impact of active galactic nuclei (AGN) on galaxy evolution. The next-generation Very Large Array (ngVLA), which will provide a ten-fold improvement in sensitivity and angular resolution compared to the current VLA, will serve as a transformational new tool in our understanding of AGN feedback as a function of redshift and environment. By combining broadband continuum data with spectral line measurements of the cold gas contents and kinematics of galaxies, the ngVLA will probe the evolution and life cycles of the radio-quiet and radio-loud AGN populations in unprecedented detail, quantify the energetic impact of AGN feedback on the star-forming reservoirs of gas-rich galaxies, and place constraints on SMBH formation and growth. Here, we present an overview of how the current reference design of the ngVLA will facilitate these advancements in our understanding of SMBH-galaxy co-evolution, with an emphasis on prospects for continuum surveys, the detection of molecular outflows out to high redshifts, and precision CO-dynamics-based SMBH mass measurements. We also discuss the importance of the next-generation Low-band Observatory (ngLOBO), a commensal low-frequency enhancement to the main ngVLA design, to maximize the utility of the ngVLA for AGN science.

One of the main objectives of the Perseverance rover is to find signs of ancient life in the Martian surface, seeking biosignatures and signs of past habitable conditions. This could be achieved with the finding of organic compounds related to life. Raman spectroscopy is among the techniques that the rover is capable of performing, which is able to detect and discern organic molecules. Perseverance carries in its payload two instruments that are able to use this technique, SuperCam for remote sensing and SHERLOC for proximity measurements. SuperCam is a long-distance instrument capable of performing several techniques (Raman, LIBS, luminescence, VISIR, microphone) in order to assess the chemical and molecular composition of rocks (mineral phases and organic molecules) from a distance up to 7 m. Therefore, it could detect organics, or traces of them, from a distance before the rover gets closer.In this work, a set of Mars soil analog samples were analyzed using the Flying Model-Body Unit / Engineering Qualification Model-Mast Unit (FM-BU/EQM-MU) setup of SuperCam. Specifically, the samples were prepared in the laboratory by adsorbing adenosine 5"-monophosphate, L-glutamic acid, L-phenylalanine, and phthalic acid with different known concentrations (5 wt%, 1 wt% and 0.1 wt%) on the clay mineral montmorillonite doped with 1 wt% of Mg-perchlorate. The preparation and characterization of those samples can be found in literature [1]. The analyses were carried out at a 2 m distance from the targets, with a laser spot size of around 300 µm at that distance. SuperCam showed excellent results for the pure compounds, before adsorption on the clay mineral. At 5 wt% concentration, the Raman signals of the organics were barely visible and at 1 wt% they were no longer visible. This fact means that if the laser of SuperCam hits an organic "hotspot" in a rock from a distance, it will be able to detect it as long as it has a concentration around 5 wt% or greater in the analyzed area, allowing SHERLOC to do further contact analysis afterwards. In addition, the SuperCam results were compared with those obtained with a commercial laboratory instrument (Renishaw inVia), obtaining the same main signals and only missing some minor secondary bands.[1] T. Fornaro, J. R. Brucato, G. Poggiali, M. A. Corazzi, M. Biczysko, M. Jaber, D. I. Foustoukos, R. M. Hazen, A. Steele, UV irradiation and Near Infrared characterization of laboratory Mars soil analog samples, Frontiers in Astronomy and Space Sciences, 2020, 7, 1-20

Ma_Miss, integrated inside the ExoMars-2018 Rover Drill, is a miniaturized VIS-NIR spectrometer for the investigation of the martian shallow subsurface.

Polarimetric study of atmospherless bodies is a powerful tool to determine their physical properties (albedo, diameter) [1]. The "Calern Asteroids Polarimetric Survey" polarimeter has been designed for this purpose. It is a "single shot" CCD polarimeter based on a "double-Wollaston" configuration [3, 4]. This allows to measure simultaneously the three Stokes parameters I, Q and U without any moving parts. This instrument has been designed for the F/12.5 Cassegrain focus of the 1 meter West telescope of the "Centre Pédagogique Planète et Univers" facility (C2PU, Observatoire de la Côte d'Azur, Plateau de Calern, France). We present in this talk the first calibration and measurements made with CAPS. The results show that the instrument remained stable with a precision of 10-4 during the whole observing campaign (two months). We also present the very first polarimetric measurements on 30 main belt asteroids, in good agreement with previously published results.

We discuss variations in the Io radiance observed by Juno/JIRAM in its M-band centered at 4.78 µm on a hemispherical scale and over time.We considered the Io infrared imagery acquired by JIRAM in a four-year period from sequence JM0061 (May 2017) to sequence JM0331 (April 2021). We collapse each Io image into scalar values representative of the mean and median radiance value of its dayside and nightside (geometric quantities associated with each dayside/nightside observation, such as latitude, longitude, phase angle, solar incidence angle, emission angle and local solar time, are also collapsed to their mean and median values).While dayside data require the application of a comprehensive, pixel-by-pixel photometric correction prior to collapsing each image, in nightside data no photometric correction is needed and the measured signal is dominated by the thermal emission of the volcanic vents, because the effect of Jupitershine, when present, is smaller. We repeat the analysis by using "super-resolution" images, each of which represents the average of several JIRAM acquisitions obtained a few minutes apart, which allows for a higher SNR to be achieved.We show trends of mean/median radiance as a function of parameters such as mean/median latitude and longitude, as well as mean/median anomaly, to investigate the potential emergence of correlations between average volcanic activity, location of the major eruptive centers, and location of Io along its orbit. Acknowledgements: JIRAM is funded by the Italian Space Agency (ASI), ASI-INAF contract 2016-23-H.0. The JIRAM instrument was built by Selex ES, under the leadership of the Italian National Institute for Astrophysics, Institute for Space Astrophysics and Planetology (INAF-IAPS), Rome, Italy. JIRAM is operated by INAF-IAPS, Rome, Italy. Support of the Juno Science and Operations Teams is gratefully acknowledged.

We present new spectroscopic observations of 17 putative basaltic asteroids, in the 0.3-2.5 micron spectral band, with the ESO/XShooter facility. The observed spectral range encompasses the two pyroxene bands centred at 0.9 and 2.0 micron, typical of the basaltic asteroids. The data allowed to taxonomically classify the observed asteroids, and in some cases to confirm their basaltic nature.

Description of the project of a VR application for smartphone on the mission BepiColombo and the exploration of the planet Mercury

Since the Rosetta mission arrived at the comet 67P/Churyumov-Gerasimenko (67/P C-G) on August 2014, the comet nucleus has been mapped by both OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System), and VIRTIS (Visible Infrared Thermal Imaging Spectrometer) acquiring a huge quantity of surface's images and spectra, producing the most detailed maps at the highest spatial resolution of a cometary nucleus. The OSIRIS imaging system (NAC & WAC) has a set of filters at different wavelengths from the ultraviolet (269 nm) to the near-infrared (989 nm). The OSIRIS imaging system has been the first instrument with the capability to map a comet surface at a high resolution reaching a maximum resolution of 11cm/px during the closest fly-by on February 14, 2015 at a distance of about 6 km from the nucleus surface while the VIRTIS spectro-imager (with two channels M and H) operates from 0.25 to 5m with medium and high spectral resolution. The spectral analysis on global scale from the VIRTIS data indicates that the nucleus presents different terrains covered by a very dark and dehydrated organic-rich material [1]. OSIRIS images indicate a morphologically complex and dark surface with a variety of terrain types and several intricate features [2]. The surface shows albedo variation and from the spectrophotometric analysis a large heterogeneity on the surface properties [3, 4, 5]. Limited evidences of exposed H2O ice have been found on the surface of 67/P C-G up to now [6, 7, 8], even though ices are considered to be a major constituent of cometary nuclei. The aim of this work is, taking advantage of the high resolution of the OSIRIS images, i) to detect the bright spots at all dimensions by albedo and spectral slope analyses, ii) to select those spots which could be resolved by VIRTIS and iii ) to deeply analyse the corresponding spectra. The OSIRIS analysis has been carried out on the colours and spectrophotometry of the whole 67/P C-G nucleus from images acquired since the first Rosetta bound orbits in August 2014 up to the end of 2015. The bright spots are spread everywhere on the surface. The analysis of the VIRTIS spectra on the selected positions by OSIRIS allowed us to detect eight spots with positive H2O ice signatures detection. The obtained results with the computed models will be presented and discussed. References : [1] Capaccioni et al. 2015. Science 347, DOI: 10.1126/science.aaa0628 [2] Sierks et al. 2015. Science 347, DOI: 10.1126/science.aaa1044 [3] Fornasier et al. 2015. A&A, 583, A30 [4] Ciarniello et al., 2015, A&A, 583, A31 [5] Oklay et al. 2016. A&A 586, A80 [6] Pommerol et al. 2015. A&A, 583, A25 [7] De Sanctis et al. 2015. Nature 525, 500 [8] Filacchione et al. 2016. Nature 529, 368.

HRIC (High Resolution Imaging Channel) is the high resolution channel of the SIMBIO-SYS instrument on- board the ESA BepiColombo Mission. Calibration activities were performed at SelexES premises in spring- summer 2014 in order to check for Channel performances (radiometric performances, quality image and geometrical performances) and to obtain data necessary to setup a calibration pipeline necessary to process the raw images acquired by the channel when in operative scenario.

Dawn spacecraft [1] entered orbit around Ceres on 6 March 2015. During the approach phase to this dwarf planet and later, through the Survey, High Altitude Mapping (HAMO) and Low Altitude Mapping Orbits (LAMO), the Visible and Infrared Mapping Spectrometer (VIR) will perform detailed observations of the surface of the body. VIR [2] is an imaging spectrometer onboard the Dawn mission and it is composed of two spectral channels: the visible (VIS) covering the 0.25 μm - 1.0 μm wavelength range and the infrared (IR) for the 0.95 μm - 5.0 μm interval. During the various phases of the mission, the surface of Ceres will be observed under different observation geometries. The measured signal is then affected by photometric issues that need to be minimized in order to exploit the intrinsic spectral variability of the surface, thus allowing the direct comparison between acquisitions taken under different observation conditions. In order to accomplish this task we perform a photometric reduction of the dataset by means of a simplified Hapke model, following the approach of [3].

Recent observations of H2O vapor plumes in localized regions [1] suggest the presence of ice on surface and/or on sub-surface regions of asteroid Ceres. In the hypothesis of a cometary-like emission mechanism (as already suggested by [2]), we performed several simulations in order to establish what are the likely physical conditions (in particular ice depth and thermal conductivity of crust) to fit Herschel observations [1].

The atmospheric fluorescent emissions of CO2 at 4.3- um have been observed in the daytime upper atmosphere of Mars from a limb geometry by the instruments OMEGA and PFS on board Mars Express [1, 8]. Initial analysis using non-local thermodynamic equilibrium (NLTE) models show that the emissions are well understood [7, 3, 6]. Yet they have not been exploited to derive important thermospheric parameters, like CO2 densities and temperatures. Our major goals are to improve current NLTE models with a joint study of OMEGA and PFS data, and to build an ambitious state-of-the-art NLTE retreival scheme for Mars. Recent progress has been made in these directions on Mars, Venus and Earth. We will present a summary of these efforts and the difficulties and expectatives for its application to the Mars Express data

The hot gas in early type galaxies (ETGs) plays a crucial role in understanding their formation and evolution. As the hot gas is often extended to the outskirts beyond the optical size, the large scale structural features identified by Chandra (including jets, cavities, cold fronts, filaments and tails) point to key evolutionary mechanisms, e.g., AGN feedback, merging history, accretion/stripping and star formation and its quenching. In our new project, the Chandra Galaxy Atlas, we systematically analyze the archival Chandra data of ~100 ETGs to study the hot ISM. Using uniformly derived data products with spatially resolved spectral information, we will present gas morphology, scaling relations and X-ray based mass profiles and address their implications.

Exoplanet magnetic fields have proven notoriously hard to detect, despite theoretical predictions of substantial magnetic field strengths on close-in extrasolar giant planets. It has been suggested that stellar and planetary magnetic field interactions can manifest as enhanced stellar activity relative to nominal age-rotation-activity relationships for main sequence stars or enhanced activity on stars hosting short-period massive planets. In a recent study of M and K dwarf exoplanet host stars, we demonstrated a significant correlation between the relative luminosity in high-temperature stellar emission lines (L(ion)/L_Bol) and the “star-planet interaction strength”, M_plan/a_plan. Here, we expand on that work with a survey of G, K, and M dwarf exoplanet host stars obtained in two recent far-ultraviolet spectroscopic programs with the Hubble Space Telescope. We have measured the relative luminosities of stellar lines C II, Si III, Si IV, and N V (formation temperatures from 30,000 - 150,000 K) in a sample of ~60 exoplanet host stars and an additional ~40 dwarf stars without known planets. We present results on star-planet interaction signals as a function of spectral type and line formation temperature, as well as a statistical comparison of stars with and without planets.