ORCID Profile
0000-0002-4158-6496
Current Organisation
INAF-Osservatorio Astronomico di Padova
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Publisher: Oxford University Press (OUP)
Date: 21-05-2019
Publisher: American Astronomical Society
Date: 03-2022
Abstract: We present the results of a Very Large Array H i imaging survey aimed at understanding why some galaxies develop long extraplanar H α tails, becoming extreme jellyfish galaxies. The observations are centered on five extreme jellyfish galaxies optically selected from the WINGS and OMEGAWINGS surveys and confirmed to have long H α tails through MUSE observations. Each galaxy is located in a different cluster. In the observations, there are in total 88 other spiral galaxies within the field of view (40′ × 40′) and observed bandwidth (6500 km s −1 ). We detect 13 of these 88 spirals, plus one uncataloged spiral, with H i masses ranging from 1 to 7 × 10 9 M ⊙ . Many of these detections have extended H i disks, two show direct evidence for ram pressure stripping, and others are possibly affected by tidal forces and/or ram pressure stripping. We stack the 75 nondetected spiral galaxies and find an average H i mass of 1.9 × 10 8 M ⊙ , which, given their average stellar mass, implies that they are very H i deficient. Comparing the extreme jellyfish galaxies to the other disk galaxies, we find that they are at smaller projected distance from the cluster center, and have a higher stellar mass and higher relative velocity than all other H i detections and most nondetections. We conclude that the high stellar mass allows extreme jellyfish galaxies to fall deeply into the cluster before being stripped, and the surrounding ICM pressure gives rise to their spectacular star-forming tails.
Publisher: EDP Sciences
Date: 11-2017
Publisher: Springer Science and Business Media LLC
Date: 08-2017
DOI: 10.1038/NATURE23462
Abstract: When a supermassive black hole at the centre of a galaxy accretes matter, it gives rise to a highly energetic phenomenon: an active galactic nucleus. Numerous physical processes have been proposed to account for the funnelling of gas towards the galactic centre to feed the black hole. There are also several physical processes that can remove gas from a galaxy, one of which is ram-pressure stripping by the hot gas that fills the space between galaxies in galaxy clusters. Here we report that six out of a s le of seven 'jellyfish' galaxies-galaxies with long 'tentacles' of material that extend for dozens of kiloparsecs beyond the galactic disks-host an active nucleus, and two of them also have galactic-scale ionization cones. The high incidence of nuclear activity among heavily stripped jellyfish galaxies may be due to ram pressure causing gas to flow towards the centre and triggering the activity, or to an enhancement of the stripping caused by energy injection from the active nucleus, or both. Our analysis of the galactic position and velocity relative to the cluster strongly supports the first hypothesis, and puts forward ram pressure as another possible mechanism for feeding the central supermassive black hole with gas.
Publisher: American Astronomical Society
Date: 20-07-2017
Publisher: American Astronomical Society
Date: 31-05-2023
Abstract: Determining which between projected local density and distance from the cluster center plays a major role in regulating morphological fractions in clusters is a longstanding debate. Reaching a definitive answer will shed light on the main physical mechanisms at play in the most extreme environments. Here we make use of the data from the OmegaWINGS survey, currently the largest survey of clusters in the local universe extending beyond 2 virial radii from the cluster cores, to extend the previous analysis outside the virial radius. Local density and clustercentric distance seems to play different roles for galaxies of different morphology: the fraction of elliptical galaxies mainly depends on local density, suggesting that their formation was linked to the primordial densities, which now correspond to the cluster cores. Only the fraction of low-mass ellipticals shows an anticorrelation with clustercentric distance, suggesting a different origin for these objects. Excluding elliptical galaxies, the relative fraction of S0s and spirals instead depends on local density only far from the cluster cores, while within the virial radius their proportion is regulated by distance, suggesting that cluster-specific processes halt the star formation and transform Sp galaxies into S0s. This interpretation is supported by literature results on the kinematical analysis of early- and late-type galaxies, according to which fast and slow rotators have distinct dependencies on halo mass and local density.
Publisher: American Astronomical Society
Date: 05-02-2018
Publisher: American Astronomical Society
Date: 03-2023
Abstract: Star-forming, H α -emitting clumps are found embedded in the gaseous tails of galaxies undergoing intense ram pressure stripping in galaxy clusters, so-called jellyfish galaxies. These clumps offer a unique opportunity to study star formation under extreme conditions, in the absence of an underlying disk and embedded within the hot intracluster medium. Yet, a comprehensive, high-spatial-resolution study of these systems is missing. We obtained UVIS/Hubble Space Telescope (HST) data to observe the first statistical s le of clumps in the tails and disks of six jellyfish galaxies from the GASP survey we used a combination of broadband (UV to I) filters and a narrowband H α filter. HST observations are needed to study the sizes, stellar masses, and ages of the clumps and their clustering hierarchy. These observations will be used to study the clump scaling relations and the universality of the star formation process, and to verify whether a disk is irrelevant, as hinted at by results from jellyfish galaxies. This paper presents the observations, data reduction strategy, and some general results based on the preliminary data analysis. The high spatial resolution of UVIS gives an unprecedentedly sharp view of the complex structure of the inner regions of the galaxies and of the substructures in the galaxy disks. We found clear signatures of stripping in regions very close in projection to the galactic disk. The star-forming regions in the stripped tails are extremely bright and compact and we did not detect a significant number of star-forming clumps in regions where MUSE did not detect any. The paper finally presents the development plan for the project.
Publisher: American Astronomical Society
Date: 20-07-2017
Publisher: American Astronomical Society
Date: 20-01-2020
Publisher: American Astronomical Society
Date: 07-08-2020
Publisher: American Astronomical Society
Date: 11-03-2019
Publisher: Oxford University Press (OUP)
Date: 19-03-2019
DOI: 10.1093/MNRAS/STZ809
Publisher: American Astronomical Society
Date: 10-07-2020
Publisher: American Astronomical Society
Date: 02-06-2020
Publisher: American Astronomical Society
Date: 17-08-2020
Publisher: American Astronomical Society
Date: 21-01-2021
Publisher: Oxford University Press (OUP)
Date: 21-11-2018
Publisher: American Astronomical Society
Date: 06-1991
DOI: 10.1086/170058
Publisher: European Southern Observatory (ESO)
Date: 2017
Publisher: Oxford University Press (OUP)
Date: 24-05-2019
Publisher: American Astronomical Society
Date: 24-10-2017
Publisher: Oxford University Press (OUP)
Date: 07-08-2018
Publisher: Oxford University Press (OUP)
Date: 10-01-2018
DOI: 10.1093/MNRAS/STY085
Publisher: American Astronomical Society
Date: 11-2022
Abstract: We present a study of barred galaxies in the cluster environment, exploiting a s le of galaxies drawn from the extended WIde-field Nearby Galaxy-cluster Survey (OmegaWINGS) that covers up to the outer regions of 32 local X-ray selected clusters. Barred galaxies are identified through a semiautomatic analysis of ellipticity and position angle profiles. We find, in agreement with previous studies, a strong codependence of the bar fraction with the galaxy stellar mass and morphological type, being maximum for massive late-type galaxies. The fraction of barred galaxies decreases with increasing cluster mass and with decreasing clustercentric distance, a dependence that vanishes once we control for morphological type, which indicates that the likelihood of a galaxy hosting a bar in the cluster environment is determined by its morphological transformation. At large clustercentric distances, we detect a dependence on the distance to the nearest neighbor galaxy, suggesting that tidal forces with close companions are able to suppress the formation of bars or even destroy them. Barred galaxies in our s le are either early-type, star-forming galaxies located within the virial radii of the clusters or late-type quenched galaxies found beyond the virial radii of the clusters. We propose a scenario in which already quenched barred galaxies that fall into the clusters are centrally rejuvenated by the interplay of the perturbed gas by ram pressure and the bar, in galaxies that are undergoing a morphological transformation.
Publisher: American Astronomical Society
Date: 12-01-2016
Publisher: American Astronomical Society
Date: 17-10-2018
Publisher: Oxford University Press (OUP)
Date: 20-02-2023
Abstract: The observed properties of galaxies are strongly dependent on both their total stellar mass and their morphology. Furthermore, the environment is known to play a strong role in shaping them. The galaxy population in the local Universe that is located in virialized clusters is found to be red, poorly star-forming, and mostly composed of early morphological types. Towards a holistic understanding of the mechanisms that drive galaxy evolution, we exploit the spectrophotometric data from the WINGS and OmegaWINGS local galaxy cluster surveys, and study the role of both the local and the large-scale environments. We attempt to disentangle their effects from the intrinsic characteristics of the galaxies, in shaping the star formation activity at fixed morphological type and stellar mass. Using a s le of field galaxies from the same surveys for comparison, we analyse the effects of the environment, embodied by the local density, clustercentric distance, and close neighbours, respectively, on the star formation histories of cluster galaxies. We find that local effects have a more relevant impact on galaxy stellar properties than the large-scale environment, and that morphology needs to be taken into account to pinpoint the mechanisms that are driving the influence of clusters in galaxy evolution.
Publisher: American Astronomical Society
Date: 06-2021
Publisher: American Astronomical Society
Date: 07-04-2020
Publisher: American Astronomical Society
Date: 28-11-2017
Publisher: American Astronomical Society
Date: 29-08-2017
Publisher: American Astronomical Society
Date: 24-05-2018
Publisher: American Astronomical Society
Date: 17-12-2019
Publisher: Oxford University Press (OUP)
Date: 02-06-2018
Publisher: Oxford University Press (OUP)
Date: 23-02-2018
DOI: 10.1093/MNRAS/STY500
Publisher: American Astronomical Society
Date: 11-01-2018
Publisher: Oxford University Press (OUP)
Date: 04-07-2019
Abstract: Exploiting the s le of 30 local star-forming, undisturbed late-type galaxies in different environments drawn from the GAs Stripping Phenomena in galaxies with MUSE (GASP), we investigate the spatially resolved star formation rate–mass ($\\rm \\Sigma _{SFR}$–$\\rm \\Sigma _\\ast$) relation. Our analysis includes also the galaxy outskirts (up to effective radii, re), a regime poorly explored by other Integral Field Spectrograph surveys. Our observational strategy allows us to detect H α out to more than 2.7re for 75 per cent of the s le. Considering all galaxies together, the correlation between the $\\rm \\Sigma _{SFR}$ and $\\rm \\Sigma _\\ast$ is quite broad, with a scatter of 0.3 dex. It gets steeper and shifts to higher $\\rm \\Sigma _\\ast$ values when external spaxels are excluded and moving from less to more massive galaxies. The broadness of the overall relation suggests galaxy-by-galaxy variations. Indeed, each object is characterized by a distinct $\\rm \\Sigma _{SFR}$ –$\\rm \\Sigma _\\ast$ relation and in some cases the correlation is very loose. The scatter of the relation mainly arises from the existence of bright off-centre star-forming knots whose $\\rm \\Sigma _{SFR}$–$\\rm \\Sigma _\\ast$ relation is systematically broader than that of the diffuse component. The $\\rm \\Sigma _{SFR}$–$\\rm \\Sigma _{tot \\, gas}$ (total gas surface density) relation is as broad as the $\\rm \\Sigma _{SFR}$–$\\rm \\Sigma _\\ast$ relation, indicating that the surface gas density is not a primary driver of the relation. Even though a large galaxy-by-galaxy variation exists, mean $\\rm \\Sigma _{SFR}$ and $\\rm \\Sigma _\\ast$ values vary of at most 0.7 dex across galaxies. We investigate the relationship between the local and global SFR–M* relation, finding that the latter is driven by the existence of the size–mass relation.
Publisher: Oxford University Press (OUP)
Date: 27-07-2018
Publisher: American Astronomical Society
Date: 04-04-2017
Location: South Africa
No related grants have been discovered for Daniela Bettoni.