Astrophysical Institute Research Articles

Measurement Campaign of Radio Frequency Interference in a Portion of the C-Band (4-5.8 GHz) for the Sardinia Radio Telescope.

Radio frequency interference (RFI) analysis is crucial for ensuring the proper functioning of a radio telescope and the quality of astronomical observations, as human-generated interference can compromise scientific data collection. The aim of this study is to present the results of an RFI measurement campaign in the frequency range of 4-5.8 GHz, a portion of the well-known C-band, for the Sardinia Radio Telescope (SRT), conducted in October-November 2023. In fact, this Italian telescope, managed by the Astronomical Observatory of Cagliari (OAC), a branch of the Italian National Institute for Astrophysics (INAF), was recently equipped with a new C-band receiver that operates from 4.2 GHz to 5.6 GHz. The measurements were carried out at three strategically chosen locations around the telescope using the INAF mobile laboratory, providing comprehensive coverage of all possible antenna pointing directions. The results revealed several sources of RFI, including emissions from radar, terrestrial and satellite communications, and wireless transmissions. Characterizing these sources and assessing their frequency band occupation are essential for understanding the impact of RFI on scientific observations. This work provides a significant contribution to astronomers who will use the SRT for scientific observations, offering a suggestion for the development of mitigation strategies and safeguarding the radio astronomical environment for future observational campaigns.

AstroEdu Conference 2023 - Preface

A collection of astronomy education endeavours from around the world presented at the AstroEdu Conference 2023 hosted by the University of Toronto - Dunlap Institute for Astronomy and Astrophysics.

Active Galactic Nuclei and Star Formation in nearby Galaxies (AGNSTRONG). I. Sample and Strategy

We introduce our project, AGNSTRONG (Active Galactic Nuclei and STaR fOrmation in Nearby Galaxies). Our research goals encompass investigating the kinematic properties of ionized and molecular gas outflows, understanding the impact of AGN feedback, and exploring the coevolution dynamics between AGN strength activity and star formation activity. We aim to conduct a thorough analysis to determine whether there is an increase or suppression in star formation rates (SFRs) among targets with and without powerful relativistic jets. Our sample consists of 35 nearby AGNs with and without powerful relativistic jet detections. Utilizing submillimeter continuum observations at 450 and 850 μm from SCUBA-2 at the James Clerk Maxwell Telescope, we determine SFRs for our sources using spectral energy distribution (SED) fitting models. Additionally, we employ high-quality, spatially resolved spectra from UV-optical to near-infrared bands obtained with the Double Spectrograph and Triple Spectrograph mounted on the 200 inch Hale Telescope at Palomar Observatory to study their multiphase gas outflow properties. This paper presents an overview of our sample selection methodology, research strategy, and initial results of our project. We find that the SFRs determined without including the submillimeter data in the SED fitting are overestimated by ∼0.08 dex compared to those estimated with the inclusion of submillimeter data. Additionally, we compare the estimated SFRs in our work with those traced by the 4000 Å break, as provided by the Max Planck Institute for Astrophysics and Johns Hopkins University catalog. We find that our determined SFRs are systematically higher than those traced by the 4000 Å break. Finally, we outline our future research plans.

Development and testing of the MicroMED sensor: From BreadBoard model to flight model

Suspended dust plays a critical role in regulating the Martian climate by influencing the atmospheric thermal gradient, altering the amount of infrared and visible energy absorbed and scattered by the atmosphere, and acting as condensation nuclei for CO2 ice-clouds particles. There are many well demonstrated, dust-related effects on martian climate which depend on dustsize, concentration, chemical and bulk composition. Currently, an accurate estimation of these parameters is lacking as they are derived from indirect measurement of the optical depth acquired from the surface and orbital data. These indirect measurements require a priori assumptions on the grain distribution curve and are hence subject to possible biases. To overcome these limitations, an optical particles counter called MicroMED has been developed under the National Institute of Astrophysics (INAF) leadership. MicroMED can measure the sizes of individual dust grains in a specific volume of air thus providing the grain size distribution and concentration. MicroMED has been selected to join the Dust Complex payload on board the ExoMars 2022. The Flight Model of the instrument has been developed and optimized starting from two prototype BreadBoard versions. Here we present the sub-systems that constitute MicroMED and their testing and characterization process, performed using the Breadboard models. We discuss the optimizations and improvements introduced on the basis of the prototype results and the overall performances of the final design.

Science with the ASTRI Mini-Array: From Experiment to Open Observatory

Although celestial sources emitting in the few tens of GeV up to a few TeV are being investigated by imaging atmospheric Čerenkov telescope arrays such as H.E.S.S., MAGIC, and VERITAS, at higher energies, up to PeV, more suitable instrumentation is required to detect ultra-high-energy photons, such as extensive air shower arrays, as HAWC, LHAASO, Tibet AS-γ. The Italian National Institute for Astrophysics has recently become the leader of an international project, the ASTRI Mini-Array, with the aim of installing and operating an array of nine dual-mirror Čerenkov telescopes at the Observatorio del Teide in Spain starting in 2025. The ASTRI Mini-Array is expected to span a wide range of energies (1–200 TeV), with a large field of view (about 10 degrees) and an angular and energy resolution of ∼3 arcmin and ∼10 %, respectively. The first four years of operations will be dedicated to the exploitation of Core Science, with a small and selected number of pointings with the goal of addressing some of the fundamental questions on the origin of cosmic rays, cosmology, and fundamental physics, the time-domain astrophysics and non γ-ray studies (e.g., stellar intensity interferometry and direct measurements of cosmic rays). Subsequently, four more years will be dedicated to Observatory Science, open to the scientific community through the submission of observational proposals selected on a competitive basis. In this paper, I will review the Core Science topics and provide examples of possible Observatory Science cases, taking into account the synergies with current and upcoming observational facilities.

The 4m International Liquid Mirror Telescope Project

The International Liquid Mirror Telescope (ILMT) project is a scientific collaboration in observational astrophysics between the Liège Institute of Astrophysics and Geophysics (Liège University, Belgium), the Aryabatta Research Institute of observational sciencES (ARIES, Nainital, India) and several Canadian universities (British Columbia, Laval, Montréal, Toronto, Victoria and York). Meanwhile, several other institutes have joined the project: the Royal Observatory of Belgium, the National University of Uzbekistan and the Ulugh Beg Astronomical Institute (Uzbekistan) as well as the Poznan Observatory (Poland). The Liège company AMOS (Advanced Mechanical and Optical Systems) has built the telescope structure that has been erected on the ARIES site in Devasthal (Uttarakhand, India). It is the first liquid mirror telescope being dedicated to astronomical observations. First light was obtained on 29th April 2022 and commissioning is being conducted at the present time. In this short article, we describe and illustrate the main components of the ILMT. We also highlight the ILMT papers presented during the third BINA workshop, which discuss various aspects of the ILMT science programs.

Estimates of Lightning Activity and Terrestrial Gamma-ray Flash Detectability at Mount Etna for the ESTHER Project

The Experiment to Study Thunderstorm High-Energy Radiation (ESTHER) is a small project of the Italian National Institute for Astrophysics (INAF), devoted to the study of high-energy emissions from thunderstorms, such as Terrestrial Gamma-ray Flashes and gamma-ray glows, which will start in 2024. In order to reduce the absorption typically undergone by gamma-ray radiation in the lower layers of the atmosphere and make these events detectable on the ground, the ESTHER set-up will be installed at high altitudes on Mt. Etna (Italy). We carried out a detailed analysis of lightning occurrence in this geographic region in order to test how suitable such a location is for the installation of a detection system to investigate thunderstorms and related emissions. The analysis pointed out a strong clustering of lightning in the proximity of the mountain peak and over the main volcano craters, where the frequent presence of volcanic ashes could increase, under the conditions of humid air typical of thunderstorms, electrical conductivity. An estimate of the gamma-ray absorption in the air undergone by typical TGF radiation allowed us to evaluate the suitability of two possible installation sites suggested for the project. This study represents a preliminary work for ESTHER and serves as a launching pad for future analyses.

Electronics and Detectors for the Stellar Intensity Interferometer of the ASTRI Mini-Array Telescopes.

The ASTRI Mini-Array is an international collaboration led by the Italian National Institute for Astrophysics (INAF) that will operate nine telescopes to perform Cherenkov and optical stellar intensity interferometry (SII) observations. At the focal plane of these telescopes, we are planning to install a stellar intensity interferometry instrument. Here we present the selected design, based on Silicon Photomultiplier (SiPM) detectors matching the telescope point spread function together with dedicated front-end electronics.

Radar observation and recontruction of Cosmos 1408 fragmentation

The population of objects in space has increased dramatically over recent decades. Space debris now represents the majority of objects in space resulting from inactive satellites, breakups, collisions and fragmentations. It has become a concern for institutions all over the world and, as such, it has led to the fostering of several programmes to counter the issues. Among these, the use of ground-based sensors for Space Surveillance Tracking (SST) activities and services and tools for analysing fragmentations play a crucial role.This work presents the activities carried out by Politecnico di Milano, Italian Space Agency and Italian National Institute of Astrophysics in this framework, using data from SST networks and the observation measurements from Bistatic Radar for LEo Survey (BIRALES), an Italian bistatic radar belonging to the EUropean Space Surveillance and Tracking (EUSST), which contributed most to the monitoring of the cloud of fragments. Exploiting Two-Line Elements (TLEs) of observed fragments, a reverse engineering approach is used to reconstruct a fragmentation in orbit through the use of the software suite PUZZLE developed at Politecnico di Milano. The analyses focus on studying the fragmentation of the Cosmos 1408 satellite, which occurred on November 15th 2021 following an Anti-SATellite (ASAT) missile test. More than 1000 trackable pieces and millions of smaller debris (estimated from numerical analysis) were produced by this event, increasing the population of inactive objects around the Earth, and threatening nearby orbiting objects.First, the processing method adopted from BIRALES in observing Cosmos debris is presented and discussed and a critical analysis about the derivable information is conducted. Then, these data and those from SST network observations are used to identify the epoch and the location of the fragmentation. In this procedure, the software toolkit PUZZLE, developed by Politecnico di Milano within a project funded by the Italian Space Agency and extended through the European Research Council, is used.

Design, Implementation, and Characterization of a Signal Acquisition Chain for SADino: The Precursor of the Italian Low-Frequency Telescope Named the Sardinia Aperture Array Demonstrator (SAAD).

Low-frequency aperture arrays represent sensitive instruments to detect signals from radio astronomic sources situated in the universe. In Italy, the Sardinia Aperture Array Demonstrator (SAAD) consists of an ongoing project of the Italian National Institute for Astrophysics (INAF) aimed to install an aperture array constituted of 128 dual-polarized Vivaldi antennas at the Sardinia Radio Telescope (SRT) site. The originally envisaged 128 elements of SAAD were re-scoped to the 16 elements of its precursor named SADino, with the aim to quickly test the system with a digital beam-former based on the Italian Tile Processing Module (iTPM) digital back-end. A preliminary measurements campaign of radio frequency interference (RFI) was performed to survey the less contaminated spectral region. The results of these measurements permitted the establishment of the technical requirements for receiving a chain for the SADino telescope. In this paper, the design, implementation, and characterization of this signal acquisition chain are proposed. The operative frequency window of SAAD and its precursor, SADino, sweeps from 260 MHz to 420 MHz, which appears very attractive for radio astronomy applications and radar observation in space and surveillance awareness (SSA) activities.

ASTEROID POSITIONS BASED ON THE DUSHANBE PART OF THE FON PROJECT OBSERVATIONS

We present the results of asteroid images’ identification and creation of positional catalogs based on digitized photographic observations within the framework of the Northern Sky Survey (FON project). Namely, the cooperation between the Ukrainian Virtual Observatory and the Institute of Astrophysics of the Academy of Sciences of Tajikistan makes it possible to expand this work by involving numerous additional archives of digitized observations and processing services to obtain new original data about the small Solar system bodies. The Dushanbe part of the FON project is represented by about 1570 photographic plates obtained in 1985—1992 at the Gissar As- tronomical Observatory of the Institute of Astrophysics of the Academy of Sciences of Tajikistan. To the moment, their digitization and further scanning processing were completed, and a catalog of equatorial coordinates and stellar magnitudes for all registered objects on the plates was created. In parallel with solving the main task of the project to create a catalog of stars and galaxies, we analyzed the results of processing the plates to search for images of asteroids and comets and to create a catalog of their coordinates and magnitudes. More than 2200 positions of asteroids and comets were obtained with visual magnitudes from 7m to 16.5 m. All positions of the asteroids were compared with the ephemeris. A preliminary analysis of the O-C differences and their comparison with similar results obtained from the digitized observations of the Kyiv and Kitab parts of the FON project are conducted. The authors note some differences in the accuracy of the compared catalogs and also analyze the reasons for this and the possibilities of reducing their impact. In addition, the catalog includes several positions of Pluto and comets that were also identified in the negatives.

PIXEL: Challenges of Designing a Professional Board Game for Astronomy Education

PIXEL - Picture (of) the Universe is a board game developed by INAF - Italian National Institute for Astrophysics in collaboration with GAME Science Research Center. The game simulates the astrophysics research environment, particularly emphasising the observation and study of cosmic bodies at different resolutions. ​​Image resolution is a crucial element in astrophysics, but the intrinsic complexity and challenges of making high-resolution images of the distant Universe are not easily and generally perceivable. We envisioned PIXEL driven by this challenge. Games intended to engage students with science either concentrate on the contents to foster the learning process or focus on life skills solicited by scientific practices. Game mechanics are then either a leverage of scientific knowledge or a science-like behavioural model, depending on the expected outcome of the game-based learning process. In addition to that, game-based learning in STEM (Science, Technology, Engineering, Mathematics) generally is designed by science practitioners and science communication and education experts. The design process of PIXEL has been a novel joint effort between scientists, science communicators, professional game designers, and game-market and award advisors. We produced a game in which the mechanics are the core of scientific learning, implicitly telling about science while making the player experience it. The innovation of this process is to obtain a game that encountered positive feedback both from the community of game experts and the educational context. The final output is a professional board game suitable for STEM education that promotes scientific citizenship in the audience.In this work, we discuss the game design process and describe how we included our scientific educational messages of image resolution and research dynamics as processes within the game mechanics without making them explicit during the gameplay. We also present a preliminary engagement evaluation of PIXEL and its efficacy in delivering implicit scientific messages through its mechanics.

A sign in space: An interdisciplinary exploration of the potential reception of an extraterrestrial signal

A Sign in Space is an interdisciplinary project by media artist Daniela de Paulis, in collaboration with the Green Bank Observatory, the National Institute for Astrophysics, the SETI Institute and the European Space Agency.The project consists in transmitting a simulated extraterrestrial message as part of a live performance, using an ESA spacecraft as celestial source. The objective of the project is to involve the worldwide search for extraterrestrial intelligence (SETI) community, professionals from different fields and the broader public in the reception, decoding and interpretation of the message. This process will require global cooperation, bridging a conversation around the topics of SETI, space research and society, across multiple cultures and fields of expertise.

“LOOK UP!” A VIRTUAL EXHIBITION ABOUT THE HISTORICAL ASTRONOMICAL ATLASES

Abstract. The new technologies are changing every aspect of our life, socially and workwise. In the same way, digital tools are becoming increasingly important to protect, preserve, and valorise cultural heritage. The digitalization of the archive’s documents and ancient books, the realisation of augmented reality apps for museums, or even the creation of virtual realities set in cultural or landscape environments that are protected or not open to visitors, are examples of the use of the new technology in the field of cultural heritage.In this context, the projects “Cosmic Pages” and “Touch the Sky” were developed. One of the main goals of these projects is the realisation of the virtual exhibition “Look up!”. It is an effective virtual tool aimed at enhancing and giving maximum dissemination of the collection of the stellar atlases, cometographies and selenographies preserved in the Observatories of the Italian National Institute for Astrophysics. This virtual exhibit was conceived and realised allowing the visitors to discover, explore, and understand how our knowledge of the cosmos, the Moon and the planets have evolved and changed with the time. Using the most advanced technologies, virtual reality, 3D models, videos etc., visitors can explore the scientific and cultural contents of the stellar and cartographic atlases.

Persistent Scatterer Interferometry (PSI) Technique for the Identification and Monitoring of Critical Landslide Areas in a Regional and Mountainous Road Network

A reliable road network is a vital local asset, connecting communities and unlocking economic growth. Every year landslides cause serious damage and, in some cases, the full disruption of many road networks, which can last from a few days to even months. The identification and monitoring of landslides with conventional methods on an extended and complex road network can be a rather difficult process, as it requires a significant amount of time and resources. The road network of the Chania regional unit on the island of Crete in Greece is a typical example, as it connects, over long distances, many remote mountainous villages with other local communities, as well as with the main urban centers, which are mainly located across the shore. Persistent scatterer interferometry (PSI) is a remote-sensing technique that can provide a reliable and cost-effective solution, as it can be used to identify and monitor slow-moving and ongoing landslides over large and complex areas such as those of the mountainous road networks. This study applied PSI in the Chania regional unit, using the novel parallelized PSI (P-PSI) processing chain, developed by the Operational Unit Center for Earth Observation Research and Satellite Remote Sensing BEYOND of the Institute of Astronomy and Astrophysics, Space Applications and Remote Sensing of the National Observatory of Athens (BEYOND) for the rapid identification of the areas, most critical to landslide in a local road network. The application of P-PSI speeded up the total required processing time by a factor of five and led to the rapid identification and monitoring of 235 new slow-moving landslides. The identified landslides were correlated with a pre-existing landslide inventory and open access visual data to create a complete landslide inventory and a relative landslide inventory map, thus offering a valuable tool to local stakeholders.

SOME REPRESENTATIVES OF THE FLORA OF THE SANGLOK MOUNTAIN (TAJIKISTAN)

The authors of the article found that on the territory of the observatory of the Institute of Astrophysics of the National Academy of Sciences of Tajikistan and its environs (Mount Sanglok) in the period from the second decade of May to the end of the first decade of June, mainly 132 plant species are in active vegetation. These plants belong to 37 families and 98 genera. Of this number, 12 species are used in traditional medicine; 26 are most often used in conventional medicine; 5 are as food plants; 2 are listed in the Red Book of the Republic of Tajikistan; and 13 are endemic plants. Among these plants, plants with the life form of hemicryptophytes dominate - 39.4% and phanerophytes - 23.5%. Of the 132 species found, the most common are representatives of the families Fаbaceae and Asteraceae - 17, Rosaceae - 16, Poaceae - 11, Lamiaceae and Brassicaceae - 8, Ranunculaceae - 6 species, and the remaining families are represented by 4, 3, 2 and 1 species.

Перспективы реализации наблюдательных программ ГАО РАН в обсерватории Ассы-Тургень

The progress of the observational programs of the Pulkovo observatory involves the transfer of some of them to regions with conducive astroclimatic conditions. The ability of the Assy-Turgen observatory (MPC = 217, h = 2700 m) operated by the Fesenkov Astrophysical Institute (AFIF), (Almaty, Republic of Kazakhstan) causes great interest in this context. The 40-cm telescope MEADE LX200 (Pulkovo Observatory) was transported to this site in 2022. In addition, it became possible to claim part of the observational time of the 1.5-meter AZT-20 telescope, which provides imaging both in the photometric mode in the griz bands and in the spectroscopic mode. The test observations were made with these instruments in August 2022. The present paper discusses the results of these observations and the prospects for further implementation of the Pulkovo observational programs at the Assy-Turgen observatory. It is shown that a positional accuracy better than 50 mas was reached with the 40-cm telescope measurements of the distant satellites of Jupiter and Saturn. Photometric measurements with this telescope allow us to obtain an accuracy of 0.02m. These are competitive values for many types of observations which will be significantly improved after the necessary deep alignment of the telescope optics. The astrometric accuracy of less than 20 mas is reachable with the AZT-20 telescope of this observatory (according to the internal convergence of astrometric measurements observations of the Uranian satellites). Spectral observations of the 61 Cygnus binary system were performed with this instrument in order to develop the method for determining the relative radial velocities. This is necessary to improve the accuracy of determining the orbital parameters of the binary star systems and searching for low-mass components and exoplanets.

Spectrographic observations of the ionized iron coronal emission lines at Pic du Midi Observatory (F) in the mid-60s

This paper is dedicated to the memory of Jean Rösch, a great figure in astronomy in the years 1947–1981 who designed, among several innovative devices, a 15-cm spectro-coronagraph. This instrument was installed at Pic du Midi observatory (south-west France), was in use during the mid-60s, fully dedicated to the observation from the ground of the coronal highly ionized iron lines, which was a true challenge at that time. This program is here reconsidered in the context of the time, at Pic du Midi observatory, which has been the cradle of routine visual coronal observations initiated by Bernard Lyot. We take advantage of this review to underline that the goals and objectives of this ground-based coronal program are taken over since 2008, by an Indian team from Bangalore (Indian Institute of Astrophysics), through a space mission (ADITYA-L1 or Sun in Sanskrit), showing a-posteriori the very innovative aspects developed with the help of this 15-cm spectro-coronagraph and thanks to the skills of J. Rösch’s collaborators.

Solar Observations with Single-Dish INAF Radio Telescopes: Continuum Imaging in the 18 – 26 GHz Range

We present a new solar radio imaging system implemented through the upgrade of the large single-dish telescopes of the Italian National Institute for Astrophysics (INAF), not originally conceived for solar observations.During the development and early science phase of the project (2018 – 2020), we obtained about 170 maps of the entire solar disk in the 18 – 26 GHz band, filling the observational gap in the field of solar imaging at these frequencies. These solar images have typical resolutions in the 0.7 – 2 arcmin range and a brightness temperature sensitivity <10 K. Accurate calibration adopting the Supernova Remnant Cas A as a flux reference provided typical errors <3% for the estimation of the quiet-Sun level components and active regions flux measurements.As the first early scientific result of the project, we present a catalog of radio continuum solar imaging observations with Medicina 32-m and SRT 64-m radio telescopes, including the multi-wavelength identification of active regions, their brightness and spectral characterization. The interpretation of the observed emission as thermal bremsstrahlung components combined with gyro-magnetic variable emission paves the way for the use of our system for long-term monitoring of the Sun. We also discuss useful outcomes both for solar physics (e.g., study of the chromospheric network dynamics) and space weather applications (e.g., flare precursors studies).

A method for digitization of archival astroplates of the Fesenkov Astrophysical Institute

The paper presents work on the analysis of archival data on different media, checking the preservation, quality of archival data, and their sorting. Based on the analysis of the archival data of the Fesenkov Astrophysical Institute, the “Digital Archive Data Log” was developed. At the moment, the digital log contains information on ∼10000 archived images. These are mainly spectra of planetary nebulae, Seyfert galaxies, and photometric images of comets. For the digitization of astroplates and frames, we have used two Epson Perfection V850 Pro scanners with additional SilverFast8 software which allows choosing the right parameters for each astroplate individually to get a reliable result. Test scans of Astronegative samples and selection of necessary parameters for scanning the entire data volume were performed. The test scanning showed that the model with a spatial resolution of 1200 dpi is the most optimal digitizing option. We have written program code in the Python programming language to automate the header of each frame. The data from the catalogs chosen to find the astrometric solutions are given in the article. The paper shows that for the digitized data the astrometric reduction can be correctly performed through astrometry.net and in the APEX II systems.