AstroBigné seminars season 2020-2021

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22/06/2021

Nicoletta Sanna

The first NIR photometry of the globular cluster G1 in M31 pdf

G1 is a massive globular cluster in M31, three times more massive than Omega Cen in the MW. The stars of this distant object have been resolved using HST. The optical photometry shows a wide red giant branch suggesting the presence of a spread in iron and/or of multiple populations. During the Science Verification of SOUL we acquired H and Ks images of G1 to perform its first near-infrared CMD. Here we present the preliminary results obtained so far.

15/06/2021

Antonino Marasco

A universal relation between the properties of supermassive black holes, galaxies, and dark matter halos pdf

We study the relations between the mass of the supermassive black hole (MBH), the dark matter halo mass (Mh) and the stellar-to-halo mass fraction (fs) in a sample of 55 nearby galaxies with dynamically measured MBH and Mh. The main improvement with respect to previous studies is that we consider both early- and late-type systems for which Mh is determined either from globular cluster dynamics or from spatially resolved rotation curves. Independently of their structural properties, galaxies in our sample build a well defined sequence in the MBH-Mh-fs three-dimensional space. We find that: (i) Mh and MBH strongly correlate with each other and anti-correlate with fs; (ii) there is a break in the slope of the MBH-Mh relation at Mh of 1e12 Msun, and in the fs-MBH relation at MBH of ∼ 1e7-1e8 Msun; (iii) at a fixed Mbh, galaxies with a larger fs tend to occupy lighter halos and to have later morphological types.
We show that the observed trends can be reproduced by a simple equilibrium model in the ΛCDM framework where galaxies smoothly accrete dark and baryonic matter at a cosmological rate, having their stellar and black hole build-up regulated both by the cooling of the available gas reservoir and by the negative feedback from star formation and active galactic nuclei (AGN). In particular, feature (ii) arises as the BH population transits from a rapidly accreting phase to a more gentle and self-regulated growth, while scatter in the AGN feedback efficiency can account for feature (iii).

08/06/2021

Francesco Salvestrini

The impact of AGN activity on the host-galaxy ISM pdf

Local Seyfert galaxies are the perfect laboratories to study whether and to what extent the emission from the Active Galactic Nuclei (AGN) affects the properties of the host-galaxy interstellar medium (ISM). This can be achieved through a multi-wavelength strategy, which allows us to fully characterise the sources in terms of AGN activity and host-galaxy properties (e.g., star formation rate, galaxy stellar mass, different gas phases).
In this work, we focused our attention on a sample of mid-IR selected Seyfert galaxies in the local Universe, which benefits from an extensive data coverage. In particular, we performed a systematic study of their nuclear activity through broad-band X-ray spectral analysis, necessary to unveil the intrinsic AGN luminosity and the level of obscuration. Exploiting mm observations (from ALMA and APEX), we characterised the host-galaxies in terms of the molecular gas component.

04/06/2021

Enrico Pinna

The special call for Adaptive Optics observations at LBT pdf

https://lbt.inaf.it/AOcallforproposals.html

01/06/2021

Matilde Signorini (UniFI)

Quasars as standard candles: most recent findings on the dispersion of the L(X)-L(UV) relation pdf

Quasars can be used as standard(izable) candles thanks to the observational evidence of the non-linear relation between the UV and the X-ray luminosities. This way of estimating luminosity distances is very promising, as quasars are numerous and observed up to very high (z~7) redshift values, and it has already produced very interesting cosmological results. However, the still-high observed dispersion of the L(X)-L(UV) relation affects both the reliability of the method and its practical implementation for cosmological analysis.
In this Astrobigné I will show the most recent findings regarding this dispersion, discussing how and how much we can lower it. I will also review the main un-removable dispersion factors and show that the intrinsic dispersion of the luminosities relation must be very low.

25/05/2021

Marco Romoli (UniFI)

Commissioning Solar Orbiter/Metis from home pdf

Solar Orbiter was launched on February 10th 2020, one month ahead of the lockdown, just at the beginning of the long payload commissioning activity. Solar Orbiter is an ESA/NASA mission aiming at taking images of the Sun from closer than any spacecraft before and for the first time look at its polar regions with a remote sensing and in situ payload. Metis is a coronagraph that will image simultaneously the solar corona in both visible light and UV HI Ly-alpha line for the first time. Characterisation and testing of Metis was performed from home by a largely diffused team. Now, Solar Orbiter is close to the start of the nominal mission phase. I will review the work done so far on Metis, the first results and what it is coming next.

11/05/2021

Viola Gelli (UniFI)

Dwarf satellites of high-z Lyman Break Galaxies: a free lunch for JWST pdf

Dwarf galaxies are the most common type of galaxies in the Universe at all epochs and they play a fundamental role in cosmic history, being responsible for the build up of massive galaxies and possibly driving the reionization and metal enrichment processes. High-redshift observations of such sources are not available yet, but we demonstrate that the James Webb Space Telescope (JWST) will catch for the first time the light of the faint satellite dwarf galaxies orbiting around massive Lyman Break Galaxies (LBGs).
We use state-of-art cosmological simulations of a typical LBG at z=6 to uncover the properties of satellite galaxies and make predictions for the upcoming JWST observations. These dwarf galaxies cover a wide range of stellar masses (log(M⋆/M⊙)≃7−9). We find that, even in such extremely dense environments, internal supernovae feedback is the key mechanism regulating their evolution, capable of completely quenching dwarf galaxies. Only the frequent merger events characterising these biased regions can effectively prolong the star-formation in the most massive satellites.
Modelling their stellar emission and dust attenuation, we reconstruct their spectral energy distributions and produce JWST/NIRCam mock images. These reveal how the instrument’s high resolution will allow us to spatially resolve these small systems from the nearby host. Color-magnitude diagrams will be a powerful diagnostic tool to infer their properties: it will be possible, for instance, to identify star-bursting, young and metal-poor satellites. Thanks to JWST’s high sensitivities, already within planned deep surveys we will detect, for the first time and for free, the faint satellite dwarf galaxies of high-z LBGs.

04/05/2021

Federico Lelli

Dynamics of high-z galaxies with cold gas observations pdf

Gas dynamics play a key role in understanding the formation and evolution of galaxies. Over the past 10 years enormous progress has been done in studying warm ionized gas in galaxies at z>1 with near-IR integral field spectrographs. The bulk of the ISM mass, however, resides in cold neutral gas. I will present recent ALMA observations of high-z galaxies targeting cold gas tracers such as atomic carbon, [CI], and ionized carbon, [CII]. These observations led to the discovery of dynamically-cold, rotationally-supported gas disks at high z, which are surprising within the standard LCDM framework of galaxy formation.

27/04/2021

Marco Padovani

The double signature of local cosmic-ray acceleration in star-forming regions pdf

Recently, there has been an increased interest in the study of the generation of low-energy cosmic rays (< 1 TeV) in shocks situated on the surface of a protostar or along protostellar jets. These locally accelerated cosmic rays offer an attractive explanation for the high levels of non-thermal emission and ionisation rate observed close to these sources. In this Astrobigné I will show that, when synchrotron emission and a high ionisation rate are measured in the same spatial region, a locally shock-accelerated cosmic-ray flux is sufficient to explain both phenomena, without having to resort to shock-generated UV photons. I will then report on the application of our recent model to the star-forming region OMC-2 FIR 3/FIR 4. Beyond the modelling of this particular system, I will explain how the combination of continuum observations at centimetre wavelengths and molecular transitions is a powerful new tool for the analysis of star-forming regions.

30/03/2021

Gianni Comoretto & Pietro Bolli

New post-doc opportunities from the PON project of SRT pdf#1 pdf#2

As part of an italian PON funding project, the Sardinia Radio Telescope is currently being upgraded with a complement of receivers, backends and ancillary instruments, in the frequency range between 22 and 100 GHz. To fully exploint these new observational capabilities, a separate PON (called PON2) has been issued to fund a series of scientific grants. Two of these grants will be issued at OAA, for two scientific projects using the W band (100 GHz) multifeed receiver and the simulteneous tri-band (22-40-98 GHz) VLBI receiver. In this talk we will describe these two instruments and their observational capabilites.

23/03/2021

Teresa Fornaro

NASA Mars 2020 Mission pdf

A key objective for Perseverance’s mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planet’s geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith for future return to Earth.
In this talk I will provide a brief overview of the mission, its rover instruments, the landing site Jezero crater, and its first achievements.
Finally, I will describe shortly my participating scientist proposal concerning the development of tools to assist the analysis of the data that the SuperCam and SHERLOC instruments will acquire for detecting vibrational features of molecular biosignatures and high preservation potential minerals.

16/03/2021

Riccardo Smareglia (INAF-OATs)

Quale roadmap per le infrastrutture informatiche dell'INAF? pdf

Nella storia recente dell'Astrofisica le infrastrutture informatiche sia di calcolo che di archiviazione e fruizione degli archivi risultano di crescente importanza per la produzione di risultati scientifici di eccellenza. La necessità di gestire volumi di dati sempre più grandi si riflette nella necessità di accedere a infrastrutture sostenibili e spesso centralizzate di scala medio - grande, che lentamente ma inesorabilmente stanno prendendo il posto delle Infrastrutture di piccola e media scala che fino ad oggi hanno caratterizzato il modo di lavorare dei ricercatori INAF. L'adesione dell’INAF a grandi infrastrutture di ricerca di livello mondiale, ad esempio SKA e CTA, e il crescente proliferare di iniziative nazionali, europee e mondiali di creazioni di cluster di calcolo o cloud di archiviazione condivisi, ha ulteriormente evidenziato questa esigenza della comunità scientifica, rendendo opportuno un cambio di passo a livello di Ente nell'approvvigionamento, gestione, offerta e coordinamento delle risorse di calcolo ed archiviazione. Occorre perciò riformare ed aggiornare l'offerta di Information technology (ICT) interna ad INAF per adeguarla alle nuove sfide che si prospettano all'orizzonte, legate ad un ruolo sempre più crescente della componente informatica nella produzione, qualificazione, conservazione e fruibilità del dato osservativo e teorico in Astronomia e Astrofisica. Il talk riassume il lavoro già fatto da ICT in questo ambito, e desidera stimolare la discussione, coinvolgendo direttamente la comunità, sullo sviluppo della nuova e-infra DATA-STAR dell'INAF.

02/03/2021

Paolo Tozzi

Where is the spider?

Searching for the adolescence of galaxies with the deepest X-ray observation of a z~2 protocluster.

23/02/2021

Maria Tsantaki

Survey of Surveys: a Gaia synergy with ground spectroscopy for homogeneous radial velocities pdf

I will present a comprehensive catalogue (Survey of Surveys, SoS) to meaningfully merge the measurements of all the large surveys to date using Gaia astrometry as a reference which contains: RAVE (Steinmetz et al. 2006), APOGEE (Majewski et al. 2017), GALAH (De Silva et al. 2015), the Gaia-ESO Survey (Gilmore et al. 2012), and LAMOST (Zhao et al. 2012). The main steps for the compilation of this catalogue include i) the cross-match algorithm (XM) between Gaia and the spectroscopic surveys and ii) the cross calibration of radial velocities between the surveys to remove biases. We use the official Gaia XM algorithm, that is used to cross-match Gaia with the main photometric and astrometric surveys on the Gaia archive (Marrese et al. 2017, 2019). The cross-calibration relies on an initial data curation and duplicates cleaning procedure to identify samples of reliable measurements in common between each survey and Gaia. A statistical analysis of the common samples is used to identify spurious trends and offsets and to perform a reliable error normalization between surveys. As a result, we provide an internally calibrated catalogue that is later validated with high quality samples (stellar clusters and high resolution spectroscopic samples). SoS guarantees homogeneity and accuracy for 10 million stars with accurate radial velocities to be applied in various fields in Astronomy.

16/02/2021

Anna Gallazzi

Galaxy evolution across environments as traced by the stellar populations fossil record pdf

The star formation history of galaxies can be affected by both internal processes and environmental processes. These leave different imprint on the properties of the stellar populations in galaxies. In particular, mean stellar age, stellar metallicity and element abundance ratios are informative of the main epoch of star formation, the efficiency and timescale of metal enrichment. We analyse the stellar populations of local galaxies in the SDSS DR7 group catalog, distinguishing galaxies that sit at the center of a group/cluster (centrals) from their satellites counterparts, and characterizing "environment" in terms of the mass of the host halo, and of the epoch of infall of satellite galaxies. We argue that the observed trends in age, metallicity, [alpha/Fe] and quiescent fraction at low masses reveal the action of satellite-specific environmental effects in a 'delayed-then-rapid' fashion. When accounting for the varying quiescent fraction and the epoch of infall, small residual excess in age, metallicity and [alpha/Fe] emerge for ancient infallers satellites in massive halos, compared to equally-massive central galaxies. This result points to the action of environment in the early phases of star formation in galaxies located close to cosmic density peaks. Pushing this kind of studies at intermediate redshift is now within reach thanks to the high-quality spectroscopy of large galaxy samples from surveys as LEGA-C, WEAVE-StePs and prospects from 4MOST.

09/02/2021

Runa Briguglio

(Easy)Redmine: a collaborative tool for managing our project pdf

In these days of social distancing and online meetings, the quest for management and organizational tools has become chaotic. Take it Easy! EasyRedmine is a project management/system engineering platform: it allows drawing a project, from task to deliverable, from requirements to risks, and run its final milestone. Although it is specifically designed for production processes, ticketing and big companies, it may be a great help also for technological and research programs in our community. Or at least it may serve as a very well organized container for informations. Moreover, the bill is paid by INAF! In the seminar I will show how to setup your own project and how to use it to manage activities, run your program together with co-workers and keep track of results and informations in general. In the background, system engineering tips and tricks will pop-up.

02/02/2021

Edvige Corbelli

Massive stars unveil the origin of the giant HI ring in Leo pdf

The origin and fate of the most extended extragalactic neutral cloud known in the Local Universe, the Leo ring, is still debated 38 years after its discovery. A 200 kpc ring made of leftover primordial gas, possibly fueling galaxies, has been considered for decades as the most promising hypothesis because of the absence of any optical counterpart. Using MUSE@VLT we have recently identified 4 tiny nebulae powered by individual massive stars with metal abundances close to or above solar. This inference, together with photometric data, convincingly demonstrates that the gas in the ring is not primordial but has been pre-enriched in a galaxy disk, later removed and shaped by tidal forces. Since then, the metal rich cloud is very slowly forming a sparse population of stars.

26/01/2021

Angela Iovino (INAF-Brera)

The plan for Positive Action in INAF 2020-2022 pdf mov

We will discuss the list of positive actions proposed to INAF by the CUG - the INAF Committee for the promotion of equal opportunities, workers' welfare, and non-discrimination.
These actions are detailed in the so-called PTAP 2020-2022.
During this Seminar, the main PTAP items will be presented, together with a few interesting statistics in INAF.

15/12/2020

Linda Podio

ALMA-DOT. From the chemistry of planet-forming disks to exoplanets atmospheres pdf

In the last five years ALMA revolutionised our comprehension of planet formation. The first breakthrough was delivered by the impacting images of the rings and gaps in protoplanetary disks, providing the first direct evidence of planet formation in fieri. On the other hand, ALMA is revolutionising also our comprehension of the disk chemistry, which is crucial to answer another key question about planet formation: what chemical composition planets inherit from their natal environment? Answering this question is the goal of the ALMA-DOT project, the ALMA chemical survey of Disk-Outflow sources in Taurus. I will show a few recent results obtained in the context of the ALMA-DOT survey, which allows us to characterise the chemical structure of disks and to investigate the chemical path from protostars to planets.

09/12/2020

Alessandra Zanazzi

D&D all'osservatorio di Arcetri pdf

L'Osservatorio di Arcetri è impegnato in molte attività sia di didattica, con bimbi e ragazzi di scuole di ogni età e con i loro docenti, sia di divulgazione con pubblico generico o specifico (ad es. famiglie, non vedenti, ecc). Abbiamo un programma davvero vario: le visite all'Osservatorio con il telescopio Amici; le attività in DaD; i laboratori di didattica innovativa, come la costruzione di circuiti di carta o la programmazione di un robot che "esplora" Marte; le attività inclusive nelle carceri o all'ospedale pediatrico; le conferenze nell'ambito di festival cittadini (o anche nazionali); il progetto di astroturismo; le Notti d'Estate e la Bambineide; i laboratori per spiegare pixel e risoluzione con i Lego; il video che mostra cosa accade nella control room dell'LBT; i progetti di alternanza scuola lavoro. Molte di queste attività sono frutto di sperimentazioni passate, ma anche oggetto di ricerca futura e vi invitiamo a collaborare con noi.

01/12/2020

Francesco Belfiore

Hot stars and diffuse gas pdf

Studies of HII regions and the ionized interstellar medium provide us with a view of star formation and chemical enrichment in galaxies from the local Universe to the highest redshifts currently observable. It is only in nearby galaxies, however, that we can probe the necessary spatial scales (~tens of pc) to study the interplay between ionizing photons from hot stars and their local environment. Such information is crucial to model the physical conditions of the so called "diffuse ionised gas" and therefore correctly interpret optical line emission in integrated spectra of galaxies. In this talk I will show how detailed studies of local galaxies are unveiling the complex relation between hot stars and this diffuse gas component.

24/11/2020

Seyma Mercimek

Chemical diversity of Class I protostars: A bridge between protostars and planet-forming disk pdf

Understanding how molecular complexity varies in Sun-like star forming regions is mandatory to comprehend whether the chemical composition of the protostellar stages is inherited by protoplanetary disks and planets. In this perspective, our ambitious overall goal is to follow the chemical evolution from the earliest protostellar stages to the relics of our pristine Solar System, i.e. comets. We investigate the chemical composition of Class I protostars, with a typical age of 105 yr. Class I sources represent a bridge between Class 0 protostars (about 104 yr), where the bulk of the material that eventually form the protostar is still in the envelope, and the protoplanetary disks (106 yr). The importance of the Class I stage has been recently strengthened by recent ALMA images showing that planet formation occurs already in disks with ages < 1 Myr. Unfortunately, only very few Class I sources, have been chemically characterized through spectral survey at millimeter wavelengths. Therefore, we are still far to conclude if Class I protostars are also a bridge from a chemical point of view.
In this talk, I will take you on a journey into the Class I world, showing the recent results on this key evolutionary stage leading to the formation of a Solar-like planetary system.

17/11/2020

Monica Ranier

Atmospheric Rossiter-McLaughlin effect and dynamics of the ultra-hot Jupiter Kelt-20b pdf

Transiting ultra-hot Jupiters are ideal candidates to study the exoplanet atmospheres and their dynamics, particularly by means of high-resolution, high signal-to-noise ratio spectra. One such object is KELT-20b, orbiting the fast rotating A2-type star KELT-20. In this talk I will describe the study of the atmospheric Rossiter-McLaughlin effect of Kelt-20b (which gives information on the extension of the planetary atmosphere), and the analysis of the planetary atmospheric trace. The latter aims to find variations in the radial velocity and width of the atmospheric signal, in order to study the dynamics of the atmosphere during the planet's transits.

10/11/2020

Giulia Carlà

Adaptive Optics and Astrometric Observations pdf

We are moving towards extremely large telescopes that will use state-of-the-art technologies to perform ground-based astrophysical observations with unprecedented resolutions. Thanks to the combination of its 39-meter diameter and the multi-conjugate adaptive optics system MAORY (Multi-conjugate Adaptive Optics RelaY), the European-Extremely Large Telescope will provide high angular resolution, diffraction-limited images on the 53x53 arcsec2 field of view of the first light near-infrared camera MICADO (Multi-AO Imaging CamerA for Deep Observations). The uniform correction of a multi-conjugate adaptive optics system, together with resolutions of ~ 4-12 mas, represents an ideal condition for astrometric observations. The goal for MICADO-MAORY is to reach astrometric precisions of ~50 µas. In this context, our purpose is to study the impact of adaptive optics correction on astrometric observations. Starting from an analytical description of the wavefront residuals produced by a specific AO correction, we analyze how the residuals of atmospheric turbulence affect the Point Spread Function along the scientific field of view and, consequently, the position's measurements. We focus our attention on the temporal aspect and we show how the choice of the scientific integration time can play an important role in providing the needed astrometric precision.

27/10/2020

Giulia Tozzi (UniFI/OAA)

Connecting X-ray nuclear winds with galaxy-scale ionised outflows in two z~1.5 quasars pdf

Outflows driven by active galactic nuclei (AGN) on kpc-scales are widely accepted to have a key-role in shaping the host galaxy evolution, but the mechanisms by which they are accelerated and propagate on galaxy-wide scales are still debated. The most promising 'engines' of the large-scale winds are X-ray Ultra-Fast outflows (UFOs), i.e. mildly-relativistic winds observed in the nuclear region of at least 40% of local AGNs, potentially capable of injecting a significant amount of energy and momentum into the ISM. In this context, we focused on two multiple-lensed QSOs known to host UFOs at z∼1.5, with the goal of constraining the wind propagation physics - for the first time ever - at epochs close to the peak of AGN activity. We used SINFONI VLT data to determine the properties of the large-scale ionised outflow traced by the [OIII]λ5007 emission line (redshifted to NIR-band). For both QSOs we detected a spatially resolved ionised wind extending more than 8 kpc from the nucleus. Comparing the UFO and the large-scale wind energetics with theoretical predictions, we found that in one case the wind is compatible with a momentum-driven propagation regime, while in the other additional momentum (such as that provided by a massive molecular wind) or a strong AGN variability are required to match theoretical expectations. To put our findings in a broader context, we considered an additional small sample of well-studied local QSOs known to be hosting both UFOs and extended outflows. We found that in 10 out of 12 galaxies, the large-scale outflow energetics is consistent with the predictions from theoretical models, suggesting that they well explain the acceleration mechanism of AGN-winds on large scales.

13/10/2020

Antonino Marasco

Galaxy-scale ionised winds driven by ultra-fast outflows in QSOs: insight on the AGN-ISM interplay pdf

X-ray studies have revealed that ~40% of the Seyfert galaxy population hosts mild-relativistic (~0.1c), powerful (1e42-1e45 erg/s) winds confined within the nuclear region at sub-pc scales. Relating the properties of these nuclear winds with those of galaxy-scale outflows traced by optical emission lines can provide fundamental clues on the physics of the AGN-ISM interplay. For this purpose, we used MUSE adaptive optics data in narrow field mode to study the properties of the ionised gas in MR 2251-178 and PG 1126-041, two nearby (z ≃ 0.06) bright quasars (QSOs) hosting UFOs. In both sources we find clear evidence for large-scale outflows and estimate mass outflow rates and kinetic efficiencies in line with those of galaxies hosting AGN of similar luminosities. The momentum rates of these ionised outflows are comparable to those measured for the UFOs at sub-pc scales, which is consistent with a momentum-driven wind propagation. Pure energy-driven winds are excluded unless about 100× additional momentum is locked in massive molecular winds. In comparing the outflow properties of our sources with those of a small sample of well-studied QSOs hosting UFOs from the literature, we find that winds seem to systematically lie either in a momentum-driven or an energy-driven regime, indicating that these two theoretical models bracket the physics of AGN-driven winds very well.

06/10/2020

Fabio Rossi

Numerical code generation from symbolic expressions in Python

An approach to numerical software development is presented, with the objective to leverage automatic symbolic expressions translation to universal functions of different numerical backends. SymPy is used to define the symbolic expressions while NumPy and CuPy are the currently supported numerical backends. This allows the non-expert in GPU programming to easily exploit GPU computational power for highly demanding numerical tasks, while having the chance to have the same formulas evaluated also on the CPU. Our approach is demonstrated in the context of Optics related computations such as Optical Propagation methods and Zernike modes covariance computation.

01/10/2020

Enrico Pinna

SOUL@LBT is calling for science!

SOUL-LUCI1 is now in an advanced commissioning phase. We will show a summary of the instrument performance measured on sky and the results obtained on a small sample of science targets. The system can already deliver high grade science data, opening a new niche for NGS AO systems. A block of 6 commissioning nights has been scheduled for science in November. We will illustrate the call for this time and answer to all questions about it.

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