Projects and Collaborations
Collaborations
Our team members work directly with with Chilean, European and North American institutions. Among them the Max-Planck-Institut für Radioastronomie (MPIfR), the European Southern Observatory (ESO), and the Canadian Hydrogen Intensity Mapping Experiment (CHIME) and its fast radio burst (FRB) backend (CHIME/FRB). We are also part of the Millimitre Wave Lab (MWL) at Universidad de Chile, collaborating in the astronomical radio transient experiment (ARTE) and other future projects. In collaboration with MPIfR we work in a variety of problems, from holography for radio telescopes (APEX and Effelsberg at mm/sub-mm and cm-long wavelengths) to observations of radio transient signals with the Effelsberg telescope. Within the CHIME/FRB Collaboration we are actively developing tools for the CHIME/FRB outriggers project. Outriggers are single dish CHIME-like cylinders spread all across North America in order to observe and localize (finding ther galactic host) FRBs. Multiple telescopes are necessary with a very long baseline in order to precisely pinpoint the FRB sky location (which is fundamental for the emission mechanism and use as probes of cosmology). Lastly, our team closely collaborates with the Italian quantum eye (Iqueye; Naletto et al. 2009) a fast photon counter capable of time tagging photons with ~0.5 ns precision. With this instrument we study the signal of pulsar and in the future transient-like events.Canadian-Chilean array for radio transient studies (CHARTS)
Fast radio bursts are bright, millisecond-long flashes of coherent radio emission distributed throughout the sky and known to originate at extragalactic distances. FRBs have been theorised to study multiple astrophysical and cosmology problems. More than ~90% of FRB events are not known to repeat (Petroff et al. 2022), making their localization to their galactic host exceedingly difficult, and hampers their use as cosmological probes. Most FRBs have been detected in the 400--800 MHz band (CHIME/FRB Collaboration et al. 2021), with frequencies near 400 MHz generally appearing to be brighter, suggesting a unique opportunity for a survey at a lower frequency band that is relatively unexplored by existing instruments. We have proposed to build a first of its kind long wavelength radio interferometer in Chile, Canadian-Chilean array for radio transient studies (CHARTS), working at a bandpass of 300--500 MHz with 256 dipole antennas which combined offer a large effective area capable of detecting low dispersion measure (DM) FRBs (enabling nearby potential galactic host localization) with an expected rate of ~100 FRBs/year. CHARTS will implement a mix of commercial and in-house developed instruments to be built at Universidad de Chile in collaboration with University of Toronto (Dunlap Institute) and the MWL. Within the third year of operation of CHARTS we will be closing commissioning operations and having a 24/7 science operating, actively searching for the enigmatic FRBs events. CHARTS is being funded by Agencia Nacional de Investigación y Desarrollo (ANID; QUIMAL fund; QUIMAL230001) and by Dunlap Seed fund (Dunlap Institute, University of Toronto). This year CHARTS will develop analog components (frequency division multiplexers and logarithmic single polarization dipole antennas), purchase digital system and start testing them at Universidad de Chile. We estimate a full deployment on site at the end of 2025 and first light by the beginning of 2026.Repeating FRBs analyses with 100-m Effelsberg telescope
Repeating FRBs are millisecond duration chromatic flashes or radio emission with no defined progenitor, although some events are thought to come from a neutron star (magnetar), their main mechanism remains a unknown. Our team is actively searching and studying activity windows of these obejects in order to characterize their astrophysical properties (and in the future perform follow-up observations). We closely collaborate with Prof. Cruces at the Pontifica Universidad Católica (Santiago, Chile).Radio instrumentation at the Atacama Pathfinder Experiment (APEX)
Aperture antennas at high frecuencies need very high precision sufaces lower than observing walvength, ~microns. This is a very challenging task, since mechanical stress and deformation loads bend the elastic surface of the radio antenna (e.g., temperature, wind, elevation). Unfortunately telescope observables are not directly related to the surface deformation, and such measurements are usually underdetermined. Phase retrieval methods such as holography for radio atennas are capable of obtaining surfafe deformations but are limited in elevation and far-field conditions from the reference antenna. Here we have implemented out-of-focus holography (Cassanelli et al. 2024) a method that is capable of measuring the surface deformation of the APEX telescope at any elevation and using strong astronomical sources. Our collaborators are Dr. Nicolás Reyes (MPIfR) and the APEX engineering team.Optical pulsar timing and optical fast transient searches
Fast photon counters are photo-detectors (e.g., single-photon avalanche diods; SPADs) capable of time tagging photons within ~nanosecond precision (over 1 h of continuous observation). These instruments were initially developed to study the first order intensity interferometry (Barbieri et al. 2023; Handbury Brown 1974), but now we are repurposing them to study transient and transient-like signals such as pulsars. Here we analyse pulsar pulses to better constrain their emission mechanims, and test our capabilities for radio transient fast counterpart detections (theorized counterparts and afterglows). Our collaborators are Prof. Naletto (Università di Padova) and Dr. Zampieri (Istituto Nazionale di Astrofisica; INAF). Our team is actively working towards bringing Iqueye to Chile by offering as a visitor instrument (VI) to the Gemini South observatory. Recently our instrument has been accepted to become a VI and within the next year we expect to have our first light.Latest AstroLab Publications
Braga C. A. et al. 2024. FRB 20121102A monitoring: updated periodicity at L-band. Submitted to A&A.