The physics of Galaxy Evolution with SPICA observations

The evolution of galaxies at Cosmic Noon (redshift 1<z<3) passed through a dust-obscured phase, during which most stars formed and black holes in galactic nuclei started to shine, which cannot be seen in the optical and UV, but it needs rest frame mid-to-far IR spectroscopy to be unveiled. At these frequencies, dust extinction is minimal and a variety of atomic and molecular transitions, tracing most astrophysical domains, occur. The future IR space telescope mission, SPICA, currently under evaluation for the 5th Medium Size ESA Cosmic Vision Mission, fully redesigned with its 2.5 m mirror cooled down to T < 8K will perform such observations. SPICA will provide for the first time a 3-dimensional spectroscopic view of the hidden side of star formation and black hole accretion in all environments, from voids to cluster cores over 90% of cosmic time. Here we outline what SPICA will do in galaxy evolution studies.Comment: Contributed talk at the IAU Symp 359 Galaxy Evolution and Feedback Across Different Environments, 2020 March 2-6, Bento Concalves, Brazil. arXiv admin note: text overlap with arXiv:1911.1218

Models of emission line profiles and spectral energy distributions to characterize the multi-frequency properties of active galactic nuclei

The spectra of Active Galactic Nuclei (AGNs) are often characterized by a wealth of emission lines with different profiles and intensity ratios that led to a complicated classification. Their electro-magnetic radiation spans more than 10 orders of magnitude in frequency. In spite of the differences between various classes, the origin of their activity is attributed to a combination of emitting components, surrounding an accreting Super Massive Black Hole, in the so called Unified Model. Currently, the execution of sky surveys, with instruments operating at various frequencies, provides the possibility to detect and to investigate the properties of AGNs on very large statistical samples. Thanks to the spectroscopic surveys that allow investigation of many objects, we have the opportunity to place new constraints on the nature and evolution of AGNs. In this contribution we present the results obtained by working on multi-frequency data and we discuss their relations with the available optical spectra. We compare our findings with the AGN Unified Model predictions, and we present a revised technique to select AGNs of different types from other line emitting objects. We discuss the multi-frequency properties in terms of the innermost structures of the sources.Comment: 11 pages, 4 figures. Proceedings of the XI Serbian Conference on Spectral Line Shapes in Astrophysics. Accepted for publication on Atom

Galaxy evolution studies with the SPICA telescope

Lines in the mid- to far-infrared wavelength range, less affected by dust extinction than optical lines, are ideally suited to study the physical processes taking place in the dust-hidden regions in galaxies, where heavily obscured star formation and accretion onto supermassive black-holes at their nuclei take place. These tools are fundamental for the study of local galaxies, but become of paramount importance to probe galaxies at the “Cosmic Noon”, at redshift z1-3, when the peak of star formation activity has taken place and most of the baryonic mass in galaxies has been assembled. One of the main goals of this Thesis is to provide reliable calibrations of mid- to far-IR ionic fine structure lines, H2 molecular lines and PAH (polycyclic aromatic hydrocarbon features), that will be used in the near and mid term to derive crucial information on the physics driving galaxy evolution. Based on these calibrations I identify the best spectroscopic measurements for the star formation rate and the black hole accretion rate in galaxies. This is done by comparing the marginal correlation of the different line luminosities versus the total IR luminosity for three samples of galaxies in the local Universe: star-forming galaxies, active galactic nuclei, and low-metallicity dwarf galaxies. For the most commonly observed fine-structure lines in the far-IR, I compare the calibrations derived from local galaxies to the existing ALMA observations of high redshift galaxies, finding an excellent agreement. These calibrations will be exploited for distant galaxies by present and future ground-based facilities observing in the millimeter and sub-millimeter range, and for galaxies in the nearby Universe through mid-IR spectroscopic observations with the upcoming James Webb Space Telescope (JWST). The second goal of this Thesis is to design future spectro-photometric surveys that will be able to address the most challenging problems that limit our current understanding of the galaxy evolution: the co-evolution of star formation and black hole accretion, the build-up of heavy elements and the chemical evolution of galaxies, and the feedback from active galactic nuclei. Using my calibration of the mid- to far-IR lines as a basis, I have simulated deep spectro -photometric surveys covering large cosmological volumes over extended fields (1–15 deg2) with an imaging spectrometer covering the mid-IR spectral range (17–36m interval), following the study case of the SPace Infrared telescope for Cosmology and Astrophysics (SPICA). A SPICA-like mission would be able to provide an unobscured three-dimensional view of galaxy evolution back to an age of the universe of less than 3 Gyrs. This survey strategy would produce a full census of the Star Formation Rate in the Universe, using PAH bands and fine-structure ionic lines, reaching the characteristic knee of the galaxy luminosity function, where the bulk of the population is distributed, at any redshift up to z3.5. Deep follow-up pointed spectroscopic observations with grating spectrometers onboard the satellite, from mid- to far-IR spectral range, would also measure the Black Hole Accretion Rate from high-ionisation fine-structure lines down to the knee of their luminosity function. Moreover, other two relevant goals of IR spectroscopic observations from space are the studies of feedback from AGN/starburst galaxies and of the metallicity evolution. While at the present time the SPICA mission will not be further developed, a similar study on galaxy evolution can be partially addressed by the ALMA telescope in the mm/sub-mm range, and the James Webb Space Telescope (JWST) in the mid-IR. These facilities, while unable to perform wide-field blind surveys, will allow to study the processes that led to the Cosmic Noon,using the ALMA telescope to observe galaxies at redshift above z3, and the late evolution of galaxies after their peak activity, with JWST observing local galaxies up to redshift z1

Effetti di profondita ottica lungo il profilo delle righe di Balmer dell'idrogeno in galassie di tipo Narrow Line Seyfert 1

ANALIZZANDO LO SPETTRO DI UN CAMPIONE DI 296 GALASSIE DI TIPO NLS1 SI SONO ISOLATE LE COMPONENTI ALLARGATE DELLE RIGHE H-alpha E H-beta, PER POI ANALIZZARNE IL RAPPORTO TRA LE LARGHEZZE A METÀ ALTEZZA. L’ANALISI VUOLE APPROFONDIRE LO STUDIO DELLE CONDIZIONI DI PROFONDITÀ OTTICA NELLA BLR DI QUESTI OGGETTI, TROVANDO CHE NELLA MAGGIOR PARTE DEI CASI, LE RIGHE SONO EMESSE DA GAS OTTICAMENTE SOTTILE

Galaxy evolution through infrared and submillimeter spectroscopy: Measuring star formation and black hole accretion with JWST and ALMA

Rest-frame mid- to far-infrared spectroscopy is a powerful tool to study how galaxies formed and evolved, because a major part of their evolution occurs in heavily dust enshrouded environments, especially at the so-called Cosmic Noon. Using the calibrations of IR lines we predict the expected fluxes of lines and features, with the aim to measure the star formation rate and the Black Hole Accretion rate in intermediate to high redshift galaxies. The launch of the James Webb Space Telescope will allow us a deep investigation of both the SF and the BHA obscured processes as a function of cosmic time. We assess the spectral lines and features that can be detected by JWST-MIRI in galaxies and Active Galactic Nuclei up to redshift z= 3. We confirm the fine-structure lines of [MgIV]4.49um and [ArVI]4.53um as good BHA rate tracers for the 1<z<3 range, and we propose the [NeVI]7.65um line as the best tracer for redshifts of z<1.5. We suggest the use of the [ArII]6.98um and [ArIII]8.99um lines to measure the SF rate, for z<3 and z<2. At higher redshifts, the PAH features at 6.2um and 7.7um can be observed at z<3 and z<2.7 respectively. Rest-frame far-IR spectroscopy is currently being collected in high redshift galaxies (z>3) with the Atacama Large Millimeter Array. We confirm that the [CII]158um line is a good tracer of the SF rate and can in most cases (0.9<z<2 and 3<z<9) be observed, and we propose the use of the combination of [OIII]88um and [OI]145um lines as an alternative SF rate tracer, that can be detected above z>3. We conclude, however, that the current and foreseen facilities will not be able to cover properly the peak of the obscured SF and BHA activities at the Cosmic Noon of galaxy evolution and a new IR space telescope, actively cooled to obtain very good sensitivities, covering the full IR spectral range from about 10um to 300um, will be needed.Comment: Accepted by PAS

Calibration of mid- to far-infrared spectral lines in galaxies

Context. Mid- to far-infrared (IR) lines are suitable in the study of dust-obscured regions in galaxies because dust extinction strongly decreases with wavelength, and therefore IR spectroscopy allows us to explore the most hidden regions of galaxies, where heavily obscured star formation as well as accretion onto supermassive black holes at the nuclei of galaxies occur. This is mostly important for the so-called cosmic noon (i.e. at redshifts of 1 < z < 3), at which point most of the baryonic mass in galaxies has been assembled. Aims. Our goal is to provide reliable calibrations of the mid- to far-IR ionic fine-structure lines, the brightest H2 pure rotational lines, and the polycyclic aromatic hydrocarbon (PAH) features, which we used to analyse current and future observations in the mm-submm range from the ground, as well as mid-IR spectroscopy from the upcoming James Webb Space Telescope. Methods. We used three samples of galaxies observed in the local Universe: star-forming galaxies (SFGs, 196), active galactic nuclei (AGN; 90−150 for various observables), and low-metallicity dwarf galaxies (40). For each population, we derive different calibrations of the observed line luminosities versus the total IR luminosities. Results. Through the resulting calibrations, we derive spectroscopic measurements of the star formation rate (SFR) and of the black hole accretion rate (BHAR) in galaxies using mid- and far-IR fine-structure lines, H2 pure rotational lines and PAH features. In particular, we derive robust star formation tracers based on the following: the [CII]158 μm line; the sum of the two far-IR oxygen lines, the [OI]63 μm line, and the [OIII]88 μm line; a combination of the neon and sulfur mid-IR lines; the bright PAH features at 6.2 and 11.3 μm; as well as – for the first time – the H2 rotational lines at 9.7, 12.3, and 17 μm. We propose the [CII]158 μm line, the combination of the two neon lines ([NeII]12.8 μm and [NeIII]15.5 μm), and, for solar-like metallicity galaxies that may harbour an AGN, the PAH 11.3 μm feature as the best SFR tracers. On the other hand, a reliable measure of the BHAR can be obtained using the [OIV]25.9 μm and the [NeV]14.3 and 24.3 μm lines. For the most commonly observed fine-structure lines in the far-IR, we compare our calibration with the existing ALMA observations of high-redshift galaxies. We find an overall good agreement for the [CII]158 μm line for both AGN and SFGs, while the [OIII]88 μm line in high-z galaxies is in better agreement with the low-metallicity local galaxies (dwarf galaxy sample) than with the SFGs, suggesting that high-z galaxies might have strong radiation fields due to low metal abundances, as expected

Unveiling the physical processes that regulate Galaxy Evolution with SPICA observations

To study the dust obscured phase of the galaxy evolution during the peak of the Star Formation Rate (SFR) and the Black Hole Accretion Rate (BHAR) density functions ($z = 1 - 4$), rest frame mid-to-far infrared (IR) spectroscopy is needed. At these frequencies, dust extinction is at its minimum and a variety of atomic and molecular transitions, tracing most astrophysical domains, occur. The future IR space telescope mission, SPICA, fully redesigned with its $2.5, mm$ mirror cooled down to T < 8, mK, will be able to perform such observations. With SPICA, we will: 1) obtain a direct spectroscopic measurement of the SFR and of the BHAR histories, 2) measure the evolution of metals and dust to establish the matter cycle in galaxies, 3) uncover the feedback and feeding mechanisms in large samples of distant galaxies, either AGN- or starburst-dominated, reaching lookback times of nearly 12 Gyr. SPICA large-area deep surveys will provide low-resolution, mid-IR spectra and continuum fluxes for unbiased samples of tens of thousands of galaxies, and even the potential to uncover the youngest, most luminous galaxies in the first few hundred million years. In this talk a brief review of the scientific preparatory work that has been done in extragalactic astronomy by the SPICA Collaboration will be given

Long-term outcome and prospective validation of NIH response criteria in 39 patients receiving imatinib for steroid-refractory chronic GVHD

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Mid-IR cosmological spectrophotometric surveys from space: Measuring AGN and star formation at the cosmic noon with a SPICA-like mission

Abstract We use the SPace Infrared telescope for Cosmology and Astrophysics (SPICA) project as a template to demonstrate how deep spectrophotometric surveys covering large cosmological volumes over extended fields (1– $15\, \rm{deg^2}$ ) with a mid-IR imaging spectrometer (17– 36\, \rm{\rm{\upmu m}} ) in conjunction with deep 70\, \rm{\rm{\upmu m}} photometry with a far-IR camera, at wavelengths which are not affected by dust extinction can answer the most crucial questions in current galaxy evolution studies. A SPICA-like mission will be able for the first time to provide an unobscured three-dimensional (3D, i.e. x, y, and redshift z) view of galaxy evolution back to an age of the universe of less than $\sim$ 2 Gyrs, in the mid-IR rest frame. This survey strategy will produce a full census of the Star Formation Rate (SFR) in the universe, using polycyclic aromatic hydrocarbons (PAH) bands and fine-structure ionic lines, reaching the characteristic knee of the galaxy luminosity function, where the bulk of the population is distributed, at any redshift up to $z \sim 3.5$ . Deep follow-up pointed spectroscopic observations with grating spectrometers onboard the satellite, across the full IR spectral range (17– 210\, \rm{\rm{\upmu m}} ), would simultaneously measure Black Hole Accretion Rate (BHAR), from high-ionisation fine-structure lines, and SFR, from PAH and low- to mid-ionisation lines in thousands of galaxies from solar to low metallicities, down to the knee of their luminosity functions. The analysis of the resulting atlas of IR spectra will reveal the physical processes at play in evolving galaxies across cosmic time, especially its heavily dust-embedded phase during the activity peak at the cosmic noon ( $z \sim 1$ –3), through IR emission lines and features that are insensitive to the dust obscuration