| 1. |
- Béthermin, Matthieu, et al.
(författare)
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The ALMA-ALPINE [CII] survey: Kennicutt-Schmidt relation in four massive main-sequence galaxies at z ~ 4.5
- 2023
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 680
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Tidskriftsartikel (refereegranskat)abstract
- Aims. The Kennicutt-Schmidt (KS) relation between the gas and the star formation rate (SFR) surface density (Σgas - ΣSFR) is essential to understand star formation processes in galaxies. To date, it has been measured up to z ~ 2.5 in main-sequence galaxies. In this Letter our aim is to put constraints at z ~ 4.5 using a sample of four massive main-sequence galaxies observed by ALMA at high resolution. Methods. We obtained ~0.3″-resolution [CII] and continuum maps of our objects, which we then converted into gas and obscured SFR surface density maps. In addition, we produced unobscured SFR surface density maps by convolving Hubble ancillary data in the rest-frame UV. We then derived the average ΣSFR in various Σgas bins, and estimated the uncertainties using a Monte Carlo sampling. Results. Our galaxy sample follows the KS relation measured in main-sequence galaxies at lower redshift, and is slightly lower than the predictions from simulations. Our data points probe the high end both in terms of Σgas and ΣSFR, and gas depletion timescales (285-843 Myr) remain similar to z ~ 2 objects. However, three of our objects are clearly morphologically disturbed, and we could have expected shorter gas depletion timescales (≲100 Myr) similar to merger-driven starbursts at lower redshifts. This suggests that the mechanisms triggering starbursts at high redshift may be different than in the low- and intermediate-z Universe.
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| 2. |
- Vanzella, E., et al.
(författare)
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An extremely metal-poor star complex in the reionization era : Approaching Population III stars with JWST
- 2023
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 678
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Tidskriftsartikel (refereegranskat)abstract
- We present JWST/Near Infrared Spectrograph (NIRSpec) integral field spectroscopy (IFS) of a lensed Population III candidate stellar complex (dubbed Lensed And Pristine 1, LAP1), with a lensing-corrected stellar mass of ≲104 M⊙ and an absolute luminosity of MUV > −11.2 (mUV > 35.6), confirmed at redshift 6.639 ± 0.004. The system is strongly amplified (μ ≳ 100) by straddling a critical line of the Hubble Frontier Field galaxy cluster MACS J0416. Although the stellar continuum is currently not detected in the Hubble and JWST/Near Infrared Camera (NIRCam) and Near Infrared Imager and Slitless Spectrograph (NIRISS) imaging, arclet-like shapes of Lyman and Balmer lines, Lyα, Hγ, Hβ and Hα are detected with NIRSpec IFS with signal-to-noise ratios (S/N) of approximately 5 − 13 and large equivalent widths (> 300 − 2000 Å), along with a remarkably weak [O III]λλ4959, 5007 at S/N ≃ 4. LAP1 shows a large ionizing photon production efficiency, log(ξion[erg Hz−1]) > 26. From the metallicity indexes R23 = ([O III] + [O II])/Hβ ≲ 0.74 and R3 = ([O III]/Hβ) = 0.55 ± 0.14, we derive an oxygen abundance of 12 + log(O/H)≲6.3. Intriguingly, the Hα emission is also measured in mirrored subcomponents where no [O III] is detected, providing even more stringent upper limits on the metallicity if in situ star formation is ongoing in this region (12 + log(O/H) < 6). The formal stellar mass limit of the subcomponents would correspond to ∼103 M⊙ or MUV fainter than −10. Alternatively, this metal-free, pure line-emitting region could be the first case of a fluorescing H I gas region induced by transverse escaping ionizing radiation from a nearby star complex. The presence of large equivalent-width hydrogen lines and the deficiency of metal lines in such a small region make LAP1 the most metal-poor star-forming region currently known in the reionization era and a promising site that may host isolated, pristine stars.
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| 3. |
- Spinoglio, L., et al.
(författare)
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- 2017
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Ingår i: Publications Astronomical Society of Australia. - : Cambridge University Press (CUP). - 1323-3580 .- 1448-6083. ; 34
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Tidskriftsartikel (refereegranskat)abstract
- IR spectroscopy in the range 12-230 mu m with the SPace IR telescope for Cosmology and Astrophysics (SPICA) will reveal the physical processes governing the formation and evolution of galaxies and black holes through cosmic time, bridging the gap between the James Webb Space Telescope and the upcoming Extremely Large Telescopes at shorter wavelengths and the Atacama Large Millimeter Array at longer wavelengths. The SPICA, with its 2.5-m telescope actively cooled to below 8 K, will obtain the first spectroscopic determination, in the mid-IR rest-frame, of both the star-formation rate and black hole accretion rate histories of galaxies, reaching lookback times of 12 Gyr, for large statistically significant samples. Densities, temperatures, radiation fields, and gas-phase metallicities will be measured in dust-obscured galaxies and active galactic nuclei, sampling a large range in mass and luminosity, from faint local dwarf galaxies to luminous quasars in the distant Universe. Active galactic nuclei and starburst feedback and feeding mechanisms in distant galaxies will be uncovered through detailed measurements of molecular and atomic line profiles. The SPICA's large-area deep spectrophotometric surveys will provide mid-IR spectra and continuum fluxes for unbiased samples of tens of thousands of galaxies, out to redshifts of z similar to 6.
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| 4. |
- Mingozzi, M., et al.
(författare)
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CO excitation in the Seyfert galaxy NGC 34 : stars, shock or AGN driven?
- 2018
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press. - 0035-8711 .- 1365-2966. ; 474:3, s. 3640-3648
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Tidskriftsartikel (refereegranskat)abstract
- We present a detailed analysis of the X-ray and molecular gas emission in the nearby galaxy NGC 34, to constrain the properties of molecular gas, and assess whether, and to what extent, the radiation produced by the accretion on to the central black hole affects the CO line emission. We analyse the CO spectral line energy distribution (SLED) as resulting mainly from Herschel and ALMA data, along with X-ray data from NuSTAR and XMM-Newton. The X-ray data analysis suggests the presence of a heavily obscured active galactic nucleus (AGN) with an intrinsic luminosity of L1-100 (keV) similar or equal to 4.0 x 10(42) erg s(-1). ALMA high-resolution data (theta similar or equal to 0.2 arcsec) allow us to scan the nuclear region down to a spatial scale of approximate to 100 pc for the CO(6-5) transition. We model the observed SLED using photodissociation region (PDR), X-ray-dominated region (XDR), and shock models, finding that a combination of a PDR and an XDR provides the best fit to the observations. The PDR component, characterized by gas density log(n/cm(-3)) = 2.5 and temperature T = 30 K, reproduces the low-J CO line luminosities. The XDR is instead characterized by a denser and warmer gas (log(n/cm(-3)) = 4.5, T = 65 K), and is necessary to fit the high-J transitions. The addition of a third component to account for the presence of shocks has been also tested but does not improve the fit of the CO SLED. We conclude that the AGN contribution is significant in heating the molecular gas in NGC 34.
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| 5. |
- Pozzi, F., et al.
(författare)
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CO excitation in the Seyfert galaxy NGC 7130
- 2017
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press. - 0035-8711 .- 1365-2966 .- 1745-3925 .- 1745-3933. ; 470:1, s. L64-L68
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Tidskriftsartikel (refereegranskat)abstract
- We present a coherent multiband modelling of the carbon monoxide (CO) spectral energy distribution of the local Seyfert galaxy NGC 7130 to assess the impact of the active galactic nucleus (AGN) activity on the molecular gas. We take advantage of all the available data from X-ray to the submillimetre, including ALMA data. The high-resolution (~0.2 arcsec) ALMA CO(6-5) data constrain the spatial extension of the CO emission down to an ~70 pc scale. From the analysis of the archival Chandra and NuSTAR data, we infer the presence of a buried, Compton-thick AGN of moderate luminosity, L2-10 keV ~1.6 × 1043 erg s-1. We explore photodissociation and X-ray-dominated-region (PDR and XDR) models to reproduce the CO emission. We find that PDRs can reproduce the CO lines up to J ~ 6; however, the higher rotational ladder requires the presence of a separate source of excitation. We consider X-ray heating by the AGNs as a source of excitation, and find that it can reproduce the observed CO spectral energy distribution. By adopting a composite PDR+XDR model, we derivemolecular cloud properties. Our study clearly indicates the capabilities offered by the current generation of instruments to shed light on the properties of nearby galaxies by adopting state-of-the-art physical modelling.
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| 6. |
- Talia, M., et al.
(författare)
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ALMA view of a massive spheroid progenitor : a compact rotating core of molecular gas in an AGN host at z=2.226
- 2018
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Ingår i: Monthly notices of the Royal Astronomical Society. - : OXFORD UNIV PRESS. - 0035-8711 .- 1365-2966. ; 476:3, s. 3956-3963
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Tidskriftsartikel (refereegranskat)abstract
- We present ALMA observations at 107.291 GHz (band 3) and 214.532 GHz (band 6) of GMASS 0953, a star-forming galaxy at z = 2.226 hosting an obscured active galactic nucleus (AGN) that has been proposed as a progenitor of compact quiescent galaxies (QGs). We measure for the first time the size of the dust and molecular gas emission of GMASS 0953 that we find to be extremely compact (similar to 1 kpc). This result, coupled with a very high interstellar medium (ISM) density (n similar to 10(5.5) cm(-3)), a low gas mass fraction (similar to 0.2), and a short gas depletion time-scale (similar to 150 Myr), implies that GMASS 0953 is experiencing an episode of intense star formation in its central region that will rapidly exhaust its gas reservoirs, likely aided by AGN-induced feedback, confirming its fate as a compact QG. Kinematic analysis of the CO(6-5) line shows evidence of rapidly rotating gas (V-rot = 320(-53)(+92) km s(-1)), as observed also in a handful of similar sources at the same redshift. On-going quenching mechanisms could either destroy the rotation or leave it intact leading the galaxy to evolve into a rotating QG.
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| 7. |
- Malapelle, Umberto, et al.
(författare)
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Predictive molecular pathology in the time of coronavirus disease (COVID-19) in Europe
- 2021
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Ingår i: Journal of Clinical Pathology. - : BMJ. - 0021-9746 .- 1472-4146. ; 74:6, s. 391-395
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Tidskriftsartikel (refereegranskat)abstract
- Aims Lung cancer predictive biomarker testing is essential to select advanced-stage patients for targeted treatments and should be carried out without delays even during health emergencies, such as the coronavirus (COVID-19) outbreak. Methods Fifteen molecular laboratories from seven different European countries compared 4 weeks of national lockdown to a corresponding period in 2019, in terms of tissue and/or plasma-based molecular test workload, analytical platforms adopted, number of cases undergoing programmed death-ligand1 (PD-L1) expression assessment and DNA-based molecular tests turnaround time. Results In most laboratories (80.0%), tissue-based molecular test workload was reduced. In 40.0% of laboratories (6/15), the decrease was >25%, and in one, reduction was as high as 80.0%. In this instance, a concomitant increase in liquid biopsy was reported (60.0%). Remarkably, in 33.3% of the laboratories, real-time PCR (RT-PCR)-based methodologies increased, whereas highly multiplexing assays approaches decreased. Most laboratories (88.9%) did not report significant variations in PD-L1 volume testing. Conclusions The workload of molecular testing for patients with advanced-stage lung cancer during the lockdown showed little variations. Local strategies to overcome health emergency-related issues included the preference for RT-PCR tissue-based testing methodologies and, occasionally, for liquid biopsy.
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| 8. |
- Salvestrini, F., et al.
(författare)
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The molecular gas properties in local Seyfert 2 galaxies
- 2022
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 663, s. 1DUMM-
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Tidskriftsartikel (refereegranskat)abstract
- Aims. We present a multiwavelength study of the molecular gas properties of a sample of local Seyfert 2 galaxies to assess if, and to what extent, the presence of an active galactic nucleus (AGN) can affect the interstellar medium (ISM) properties in a sample of 33 local Seyfert 2 galaxies. Methods. We compare the molecular gas content (MH2) derived from new and archival low-J CO line measurements of a sample of AGN and a control sample of star-forming galaxies (SFGs). Both the AGN and the control sample are characterized in terms of host-galaxy properties, for example stellar and dust masses (M* and Mdust, respectively) and the star formation rate (SFR). We also investigate the effect of AGN activity on the emission of polycyclic aromatic hydrocarbon (PAH) molecules in the mid-infrared (MIR), a waveband where the dust-reprocessed emission from the obscured AGN contributes the most. Result. The AGN hosted in less massive galaxies (i.e., M* < 1010.5 M⊙; Mdust < 107.5 M⊙) show larger molecular gas contents with respect to SFGs that have the same stellar and dust masses. When comparing their depletion times (tdep ≈ MH2/SFR), AGN show tdep ∼ 0.3-1.0 Gyr, similar to the times observed in the control sample of SFGs. Seyfert 2 galaxies show fainter PAH luminosity the larger the dominance of the nuclear activity in the MIR. Conclusions. We find no clear evidence for a systematic reduction in the molecular gas reservoir at galactic scales in Seyfert galaxies with respect to SFGs. This is in agreement with recent studies that show that molecular gas content is only reduced in sub-kiloparsec-sized regions, where emission from the accreting supermassive black hole dominates. Nonetheless, we show that the impact of AGN activity on the ISM is clearly visible as a suppression of the PAH luminosity.
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