OA@INAF - Istituto Nazionale di Astrofisica
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A fast-rotator post-starburst galaxy quenched by supermassive black-hole feedback at z = 3
Get PDFThe most massive galaxies in the Universe stopped forming stars due to the time-integrated feedback from central supermassive black holes (SMBHs). However, the exact quenching mechanism is not yet understood, because local massive galaxies were quenched billions of years ago. Here we present JWST/NIRSpec integral-field spectroscopy observations of GS-10578, a massive, quiescent galaxy at redshift z = 3.064 ± 0.002. From its spectrum, we measure a stellar mass M⋆ = 1.6 ± 0.2 × 1011 M⊙ and a dynamical mass Mdyn = 2.0 ± 0.5 × 1011 M⊙. Half of its stellar mass formed at z = 3.7-4.6, and the system is now quiescent, with a current star-formation rate of less than 19 M⊙ yr−1. We detect ionized- and neutral-gas outflows traced by [O III] emission and Na I absorption, with mass outflow rates 0.14-2.9 and 30-100 M⊙ yr−1, respectively. Outflow velocities reach vout ≈ 1,000 km s−1, comparable to the galaxy escape velocity. GS-10578 hosts an active galactic nucleus, evidence that these outflows are due to SMBH feedback. The neutral outflow rate is higher than the star-formation rate. Hence, this is direct evidence for ejective SMBH feedback, with a mass loading capable of interrupting star formation by rapidly removing its fuel. Stellar kinematics show ordered rotation, with spin parameter λRe=0.62 ±0.07 , meaning GS-10578 is rotation-supported. This study presents direct evidence for ejective active galactic nucleus feedback in a massive, recently quenched galaxy, thus helping to clarify how SMBHs quench their hosts. The high value of λRe implies that quenching can occur without destroying the stellar disk
The TRAPUM Small Magellanic Cloud pulsar survey with MeerKAT - II. Nine new radio timing solutions and glitches from young pulsars
Get PDFWe report new radio timing solutions from a 3-yr observing campaign conducted with the MeerKAT and Murriyang telescopes for nine Small Magellanic Cloud pulsars, increasing the number of characterized rotation-powered extragalactic pulsars by 40 per cent. We can infer from our determined parameters that the pulsars are seemingly all isolated, that six are ordinary pulsars, and that three of the recent MeerKAT discoveries have a young characteristic age of under 100 kyr and have undergone a spin-up glitch. Two of the sources, PSRs J00407337 and J00487317, are energetic young pulsars with spin-down luminosities of the order of 1036 erg s-1. They both experienced a large glitch, with a change in frequency of about 30 μHz, and a frequency derivative change of order -10-14Hz s-1. These glitches, the inferred glitch rate, and the properties of these pulsars (including potentially high inter-glitch braking indices) suggest these neutron stars might be Vela-like repeating glitchers and should be closely monitored in the future. The position and energetics of PSR J00487317 confirm it is powering a new pulsar wind nebula (PWN) detected as a radio continuum source; and similarly the association of PSR J00407337 with the PWN of supernova remnant (SNR) DEM S5 (for which we present a new Chandra image) is strengthened. Finally, PSR J00407335 is also contained within the same SNR but is a chance superposition. It has also been seen to glitch with a change of frequency of Hz. This work more than doubles the characterized population of SMC radio pulsars
Thermo-mechanical design and birefringence analysis for the MezzoCielo assembly
Get PDFMezzoCielo represents a novel type of monocentric optical instrument devoted to whole-sky monitoring due to its extremely large field of view. The latter property, combined with the need to realize relative wide optical spheres (with diameters up to few meters) and the limitations related to the manufacturing of large optical elements having high performance, requires the adoption of a segmented structure, presenting, for instance, a Platonic solid-like shape, composed by several identical lenses, supported by a metallic frame along the edges of the solid itself. In this paper, the main aspects concerning the sizing of such frame (chosen to be dodecahedral) and a thermo-mechanical analysis of the lenses support assembly, both analytical and numerical, will be presented. In particular, it will be shown how the lenses are able to operate with little temperature difference across their volume independently from the surrounding conditions and the way in which the telescope can withstand external low temperatures without manifesting high thermal stresses, while maintaining, at the same time, constant focal length. Subsequently, a birefringence investigation completes the opto-mechanical analysis and it will be employed as a further instrument to select the more appropriate lens shape. Eventually, the same analysis is repeated for all the twelve lenses of the dodecahedral structure
EUSO-SPB1 mission and science
Get PDFThe Extreme Universe Space Observatory on a Super Pressure Balloon 1 (EUSO-SPB1) was launched in 2017 April from Wanaka, New Zealand. The plan of this mission of opportunity on a NASA super pressure balloon test flight was to circle the southern hemisphere. The primary scientific goal was to make the first observations of ultra-high-energy cosmic-ray extensive air showers (EASs) by looking down on the atmosphere with an ultraviolet (UV) fluorescence telescope from suborbital altitude (33 km). After 12 days and 4 h aloft, the flight was terminated prematurely in the Pacific Ocean. Before the flight, the instrument was tested extensively in the West Desert of Utah, USA, with UV point sources and lasers. The test results indicated that the instrument had sensitivity to EASs of ⪆ 3 EeV. Simulations of the telescope system, telescope on time, and realized flight trajectory predicted an observation of about 1 event assuming clear sky conditions. The effects of high clouds were estimated to reduce this value by approximately a factor of 2. A manual search and a machine-learning-based search did not find any EAS signals in these data. Here we review the EUSO-SPB1 instrument and flight and the EAS search
Galaxy formation and symbiotic evolution with the inter-galactic medium in the age of ELT-ANDES
Get PDFHigh-resolution absorption spectroscopy toward bright background sources has had a paramount role in understanding early galaxy formation, the evolution of the intergalactic medium and the reionisation of the Universe. However, these studies are now approaching the boundaries of what can be achieved at ground-based 8-10m class telescopes. The identification of primeval systems at the highest redshifts, within the reionisation epoch and even into the dark ages, and of the products of the first generation of stars and the chemical enrichment of the early Universe, requires observing very faint targets with a signal-to-noise ratio high enough to detect very weak spectral signatures. In this paper, we describe the giant leap forward that will be enabled by ANDES, the high-resolution spectrograph for the ELT, in these key science fields, together with a brief, non-exhaustive overview of other extragalactic research topics that will be pursued by this instrument, and its synergistic use with other facilities that will become available in the early 2030s
Machine learning applied to fiber-fed focal plane wavefront sensing: a study of aberrated wave transmission through multimode optical fibers
Get PDFThis research explores the potential of machine learning and neural networks in recognizing the input features of aberrated wavefronts transmitted through multimode optical fibers, in view of applications for wavefront sensing in ground-based telescopes. Recent studies highlight the efficacy of multimode fibers for imaging and sensing, suggesting neural networks' effectiveness in mapping relationships between output distortions and input wavefront aberrations. The initial step of our study concerned multimode fiber propagation simulations. An input Gaussian beam was distorted with known aberrations and then sent through the fiber to analyze the effects on the output. This groundwork was used to train and validate a Convolutional Neural Network architecture. Its main role was to understand, from output images, which type of aberration was superimposed in input. We obtained promising results with test accuracy of 85% and 87%, while achieving good performance in network training and generalization
The Comet Interceptor Mission
Get PDFHere we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA's F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum Δ V capability of 600 ms−1. Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes - B1, provided by the Japanese space agency, JAXA, and B2 - that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission's science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule
SDHDF: A new file format for spectral-domain radio astronomy data
Get PDFRadio astronomy file formats are now required to store wide frequency
bandwidths and multiple simultaneous receiver beams and must be able to account
for versatile observing modes and numerous calibration strategies. The need to
capture and archive high-time and high frequency-resolution data, along with
the comprehensive metadata that fully describe the data, implies that a new
data format and new processing software are required. This requirement is
suited to a well-defined, hierarchically-structured and flexible file format.
In this paper we present the Spectral-Domain Hierarchical Data Format (`SDHDF')
-- a new file format for radio astronomy data, in particular for single dish or
beam-formed data streams. Since 2018, SDHDF has been the primary format for
data products from the spectral-line and continuum observing modes at
Murriyang, the CSIRO Parkes 64-m radio telescope, and we demonstrate that this
data format can also be used to store observations of pulsars and fast radio
bursts
MARSS: MusAB in Augmented Reality from Science to Society - relazione sui risultati di progetto
Get PDFIl progetto MARSS è iniziato il 1° settembre 2020; inizialmente il progetto (redatto nell’estate 2019)
prevedeva una durata biennale con chiusura al 31 agosto 2022.
Ad un anno dall’inizio è apparso chiaro al gruppo di lavoro che l’emergenza pandemica stava
creando difficoltà in merito all’accessibilità dei luoghi di lavoro e all’implementazione del progetto.
Nell’autunno del 2021 è stata pertanto chiesta e ottenuta da Fondazione Cariplo una proroga della
scadenza che è passata dal 31 agosto 2022 al 28 febbraio 2023.
Il perdurare della situazione pandemica nel corso del 2021 e 2022 ha inoltre messo in discussione
alcune modalità di attuazione del progetto (device da utilizzare, modalità di interazione,
accessibilità) e ha richiesto un ulteriore lavoro di ridefinizione ed implementazione.
Nell’autunno 2021 è stata inoltrata a Fondazione Cariplo la rendicontazione del primo anno di
progetto con una relazione che tenesse conto del lavoro svolto tra il 1° settembre 2020 e il 31
agosto 2021.
Qui esponiamo il lavoro svolto e i risultati ottenuti a partire dal settembre 2021 fino alla conclusione
del progetto
Detailed cool star flare morphology with CHEOPS and TESS
Get PDFContext. White-light stellar flares are proxies for some of the most energetic types of flares, but their triggering mechanism is still poorly understood. As they are associated with strong X and ultraviolet emission, their study is particularly relevant to estimate the amount of high-energy irradiation onto the atmospheres of exoplanets, especially those in their stars’ habitable zone. Aims. We used the high-cadence, high-photometric capabilities of the CHEOPS and TESS space telescopes to study the detailed morphology of white-light flares occurring in a sample of 130 late-K and M stars, and compared our findings with results obtained at a lower cadence. Methods. We employed dedicated software for the reduction of 3 s cadence CHEOPS data, and adopted the 20 s cadence TESS data reduced by their official processing pipeline. We developed an algorithm to separate multi-peak flare profiles into their components, in order to contrast them to those of single-peak, classical flares. We also exploited this tool to estimate amplitudes and periodicities in a small sample of quasi-periodic pulsation (QPP) candidates. Results. Complex flares represent a significant percentage (≳30%) of the detected outburst events. Our findings suggest that high-impulse flares are more frequent than suspected from lower-cadence data, so that the most impactful flux levels that hit close-in exoplanets might be more time-limited than expected. We found significant differences in the duration distributions of single and complex flare components, but not in their peak luminosity. A statistical analysis of the flare parameter distributions provides marginal support for their description with a log-normal instead of a power-law function, leaving the door open to several flare formation scenarios. We tentatively confirmed previous results about QPPs in high-cadence photometry, report the possible detection of a pre-flare dip, and did not find hints of photometric variability due to an undetected flare background. Conclusions. The high-cadence study of stellar hosts might be crucial to evaluate the impact of their flares on close-in exoplanets, as their impulsive phase emission might otherwise be incorrectly estimated. Future telescopes such as PLATO and Ariel, thanks to their high-cadence capability, will help in this respect. As the details of flare profiles and of the shape of their parameter distributions are made more accessible by continuing to increase the instrument precision and time resolution, the models used to interpret them and their role in star-planet interactions might need to be updated constantly