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Video arhiv astrodebat 2022/23

Roberta Tripodi: The co-evolution between SMBHs and their host-galaxies at z ∼ 6

28. februar 2023

Roberta Tripodi (INAF – Osservatorio Astronomico di Trieste)

The cold ISM and dust properties are key elements to understand the assembly and nature of the first QSOs at the Reionization Epoch. In particular, the [CII] and CO lines are bright tracers of the gas content that could be detected from distant galaxies. Measurements of the line widths, profiles and velocity maps of these emission lines reveal important information on the gas kinematics and dynamics. On the other hand, a reliable and accurate determination of the dust properties, through the analysis of the continuum emission, allows us to obtain a precise estimate for the star formation rate of the QSO’s host galaxy. In this talk, I will present results of the gas and dust of QSO J2310+1855 at z ∼ 6 based on the analysis of CO, [CII] and continuum emissions from ALMA kpc-resolution observation. This allowed us to study in detail the gas kinematics in J2310’s host galaxy, to perform a dynamical modelling of the rotation curve and to derive dust properties with high accuracy. I will also show very new results on the dust properties of the most luminous QSO at z > 6, namely QSO J0100+2802. The final goal will be to discuss the evolutionary scenario of these objects, studying the evolutionary path of their SMBHs together with the path of their host galaxies.

Video is published on this link!

Vladan Markov: The dust attenuation law and ISM properties of galaxies at the Epoch of Reionization

21. februar 2023

Vladan Markov (Scuola Normale Superiore di Pisa)

During The Epoch of Reionization (EoR), the first galaxies played a key role in the complete reionization of the Universe by z∼6 and in the metal enrichment of the intergalactic medium. Constraining the properties of early galaxies is fundamental in our understanding of galaxy evolution. Standard approach in characterizing the galaxy properties is through the spectral energy distribution (SED) fitting method with a priori assumption on the dust attenuation law (e.g. ”Calzetti” and SMC). However, the dust properties of high-z sources are not well described by the reddening curves derived for local sources. Constraining the dust attenuation law is important for characterizing the dust properties and the dust production mechanisms, but also the global properties of galaxies in the early Universe.

I will present a new tool, based on the SED fitting method, that allows us to simultaneously characterize the dust attenuation properties along with the global parameters of galaxies, without any a priori assumption on the dust law. The advantage of using this robust model, is its capability to recover the dust attenuation properties reddened by any well-known,or potential new dust curve. We test our tool on the synthetic spectra, and apply it on the James Webb Space Telescope (JWST) observations of a sample of star-forming galaxies at the EoR. Our tool and the new JWST data will provide means to constrain the dust properties of a large sample of galaxies at the EoR. I will also discuss how we combined the emission of two carbon lines, [CIII] λ1909 and [CII]158μm (which trace different phases of the ISM), in order to constrain the ISM conditions (gas density, metallicity and ”burstiness”) of high-z star-forming galaxies (Markov et al. 2022).

Video available on this link!

Nicholas Martis: Identifying and Characterizing the Most Heavily Dust-Obscured Galaxies at 1 < z < 4

16. februar 2023

Nicholas Martis (Saint Mary’s University, Halifax, Canada)

I investigate a sample of color-selected galaxies from the UltraVISTA DR3 survey of the COSMOS field in an effort to identify and characterize the most heavily dust-obscured galaxies at 1<z<4. UV-MIR spectral energy distribution (SED) modeling that allows for extreme obscuration levels reveals a population of massive, dusty galaxies with as much as four magnitudes of extinction in the V-band. We perform a detailed analysis of 65 such galaxies including their full UV-FIR SEDs incorporating Herschel photometry, sizes using Hubble Space Telescope imaging when available, and star formation activity. Finally, a comparison of the physical properties of these galaxies to those of sub-millimeter galaxies as well as Herschel sources matched in redshift and stellar mass explores the overlap of selections based on dust emission rather than dust obscuration.

Video available on this link!

Teo Močnik: Gemini Observatory: A Tale of Twin Telescopes​

14. december 2022

Teo Močnik (Gemini Telescopes)

The Gemini Observatory consists of twin 8.1 m telescopes, located on Mauna Kea in Hawaii and on the mountain of Cerro Pachon in Chile. We will virtually visit one of the telescopes and its control room, inspect our arsenal of optical and infrared instruments, take a peek at the backstage operations of the queue-based observatory, and walk through the gallery of some of our science highlights. Best of all, Slovenian astronomers can apply for Gemini observing time too!

Video: click on the image below!

Naslovnica predavanja Tea Močnika o observatoriju Gemini
Naslovnica predavanja o observatoriju Gemini, predavatelj Teo Močnik

Dr. Guy Consolmagno: Physical and thermal properties of asteroid-analog meteorites​

22. november 2022

dr. Guy Consolmagno, director of the Vatican Observatory

We have measured the physical properties (density, porosity, thermal properties) at low temperature for meteorites in classes closely associated with asteroids that have been sampled or are to be closely studied by spacecraft missions. Our results for CM meteorites (close analogs to asteroids Bennu and Ryugu) and iron meteorites (an important constituent of asteroid Psyche) have important applications in understanding their surface properties, including their contribution to Yarkovsky and YORP forces.

Video: click on the image below!

dr. Guy Consolmagno, direktor Vatikanskega observatorija
Dr. Guy Consolmagno med Astrodebato

Kelsey Glazer: Carbon at Cosmic Dawn

24. oktober 2022​

Kelsey Glazer (UC Davis)

Carbon at Cosmic Dawn is an on-going project that aims to study galaxies at the epoch of reionization. It investigates both stellar and neutral gas properties of four faint galaxies; all which are highly redshifted (z~7). We utilize ALMA and the prominent [CII] 158 μm line emission to probe these galaxies spectroscopically. In this talk I will present our preliminary results of [CII] measurements. We are able to measure [CII] line luminosities and upper limits and a velocity offset between Lyα and [CII], giving us properties of the epoch of reionization galaxies.

Video (click on the image below)
Kelsey Glazer
Kelsey Glazer, predavateljica Astrodebate