Browsing by Type "Multimedia"

An efficient diagnostic method to find local (z<0.1) Compton-thick AGN consists in selecting sources characterized by hard X- ray colors and low hard X-ray over mid-IR flux ratio. This has been done efficiently in the past using 2XMM and IRAS data (Severgnini et al. 2012). In this talk I will present my thesis work in which I tested this technique using the latest 3XMM and WISE data for the sample presented by Severgnini et al. I will also briefly discuss the X-ray spectral properties of all of those sources showing flux and/or spectral variability in the XMM-Newton observations.

Galaxy formation theories struggle to explain the role of Black Hole accretion in shaping galaxies over cosmic time. Radio feedback, associated to radio jets, is accepted as a fundamental component of the lifecycle of the most massive radio loud early-type galaxies (Radio Loud ETGs, i.e. Radio Galaxies, RGs), at least in the late stages of cosmic evolution (z < 1). The many details of such process, however, still remain poorly understood. It is generally accepted that High Excitation Radio Galaxies (HERGs) are triggered by cold gas transported to the center through merging or collisions with gas-rich galaxies, while accretion in Low Excitation Radio Galaxies (LERGs) may occur directly from the hot phase of the IGM. The most compelling evidence that cold gas can play a role in fuelling LERGs as well, is that in such systems dust and molecular gas are detected in larger quantities than in radio-quiet ETGs. The origin of this gas (external or secular) remains still unclear. Systematic high-resolution CO imaging of radio galaxies (in which radio jets are currently active) together with kinematic information on the stellar and ionized gas components, is fundamental to isolate the role played by radio-mode feedback in the overall formation and evolution of ETGs, allowing also to do a crucial comparison with existing studies of radio-quiet ETGs (e.g. ATLAS3D sample). For this purpose, we have selected a complete volume-limited sample of eleven nearby (z < 0.03) RGs associated with elliptical galaxies, selected from the Ekers et al. (1989) parent sample of 90 radio galaxies in the Southern sky. All the selected galaxies have low-power (P_1.4GHz ≤ 10^25 W Hz^-1), low accretion rate, and FRI type or (arcsec-scale) compact radio morphology. For all the sources, we have already acquired a set of multi-wavelength data, spanning from the radio to the mm regime. Here we present the results obtained so far by analyzing ALMA Cycle 3 CO(2-1) observations of 9 targets, with resolutions of few hundreds of parsecs at the source redshifts. The CO(2-1) line emission was detected in 6 out of 9 targets (detection significance from 8 to 45 sigma; 66% detection rate). CO(2-1) maps show rotating disc structures in all the sources, with some peculiar cases in which the gas disk shows a disturbed morphology that seems to suggest an interaction with the radio jets. The detected CO discs are mostly located in the inner kpc-sub-kpc scales of the host galaxy. Available optical images were used to investigate the relative distribution of gas and dust: they result mostly co-spatial, with dust extending on larger scales in some cases. The study of the CO kinematics is still ongoing, but preliminary results show hints of the presence of of non-circular motions (i.e. inflow/outflow) in at least one of the detected CO discs.

A key mode of AGN feedback is energy input from radio-emitting jets; this is common in massive early-type galaxies (ETG) and drives interactions with the multiphase intergalactic medium (IGM) surrounding them. The mechanisms by which jetted AGN are fuelled and the way in which this forms part of a feedback loop are not yet understood. A systematic study of the various gas phases (ionised and molecular) and of the stellar and dust components in a the cores of a representative sample of massive, radio-loud ETGs (in which jets are currently active) is needed to provide a crucial comparison to existing studies of radio-quiet ETGs (e.g. ATLAS^3D; Cappellari et al. 2011). In particular, it will enable a better understanding of the feeding of AGNs, and will isolate the role played by jet-induced feedback (likely the dominant feedback mode in local, massive ETGs) in the overall formation and evolution of ETGs. In this talk I will present the first results of an ongoing multiphase study of a volume-limited sample (z<0.03) of radio galaxies. For all sources, we have already gathered VLT/VIMOS IFS observations (Warren et al. in prep.) and 12CO(2-1) APEX observations (Prandoni et al. 2010; Laing et al. in prep.). ALMA follow-up for observations were obtained in Cycle 3. (Ruffa et al. in prep.).

Assessing the faint AGN component in deep radio fields, will provide an important tool to understand the role of nuclear activity in distant galaxies and its possible co-evolution with star-formation processes, as radio wavelengths are not affected by dust extinction and/or gas absorption. In my talk I will report about the e-MERLIN Galaxy Evolution Survey (eMERGE, PI: Muxlow), a legacy project which aims at undertaking a spatially-resolved study of AGN and star formation processes up to high redshift in a 30 arcmin diameter field in the GOODS-N region, through ultra-deep (sub-microJy rms), sub-arcsec (50-500 mas) imaging at 1.4 and 5 GHz, using combined JVLA and eMERLIN observations. I will focus on the study of a sample of GOODS-N galaxies (300 objects) selected at 1.4 GHz to constrain the presence of AGN cores in moderate-to-high redshift (1

Multi-wavelength studies of deep radio fields show a composite population of star-forming galaxies, radio-quiet and radio-loud AGNs, with the formers dominating at the lowest flux densities (< 100 microJy). However, the exact mixture between these types of radio sources is still matter of debate. The most direct way to identify faint AGN-driven radio emission is the detection of embedded radio cores in the host galaxies, through ultra-deep and very high resolution radio observations. This would open the perspective of studying the whole AGN population in the radio band, including the radio-quiet component traditionally selected at other wavelengths (opt/IR/X-ray). Assessing the faint AGN component in deep radio fields, will provide an important tool to understand the role of nuclear activity in distant galaxies and its possible co-evolution with star-formation processes, as radio wavelengths are not affected by dust extinction and/or gas absorption.

In my talk I will report about the e-MERLIN Galaxy Evolution Survey (eMERGE, PI: Muxlow), a legacy project which aims at undertaking a spatially-resolved study of AGN and star formation processes up to high redshift in a 30 arcmin diameter field in the GOODS-N region, through ultra-deep (sub-microJy rms), sub-arcsec (50-500 mas) imaging at 1.4 and 5 GHz, using combined JVLA and eMERLIN observations. I will focus on the 5 GHz JVLA mosaic observations and catalogue of GOODS-N (94 sources), in the framework of the eMERGE project, and on the study of a larger sample of GOODS-N galaxies (300 objects) selected at 1.4 GHz to constrain the presence of AGN cores in moderate-to-high redshift (1

The epoch between redshift of 1-3 has become the prime focus of many galaxy evolutionary studies as the accretion rates of super massive black holes at the galactic center and the star formation rates of their hosts peaked around this period, pointing to their co-evolution throughout cosmic history. We will present two different approaches to study the impact of high redshift AGN (z~1.5) on the host galaxy: a) CO(2-1) observations from ALMA in a sample of "main sequence" AGNs to compare the star formation efficiency and gas fractions in active and inactive galaxies. b) SINFONI-IFU observations of a representative sample of high redshift quasars for which we observe intermediate to high velocity outflows using [OIII]5007 line diagnostics. These outflows are extended up-to kiloparsec scales and have an asymmetric geometry. With these approaches, one is able to test the effect of AGN feedback on the molecular as well as the ionized gas content.

Lunae Planum is a Martian plain measuring approximately 1000 km in width and 2000 km in length, centered at coordinates 294°E-11°N. MOLA elevations range from +2500 m to +500 m in the south, gently sloping northward to -500 m. The plain is part of a belt of terrains located between the southern highlands and the northern lowlands, that are transitional in character (e.g., by elevation, age and morphology). These transitional terrains are poorly understood, in part because of their relative lack of major geomorphological features. They record however a very significant part of Mars's geologic history. The most evident features on Lunae Planum's Hesperian surface are regularly spaced, longitudinally striking, wrinkle ridges. These indicate the presence of blind thrust faults cutting through thick stacks of layers of volcanic or sedimentary rocks. The presence of fluidized ejecta craters scattered all over the region suggests also the presence of ice or volatiles in the subsurface. In a preliminary study of Lunae Planum's subsurface we used the Mars Express ground penetrating radar MARSIS dataset [1], in order to detect reflectors that could indicate the presence of fault planes or layering. Standard radargrams however, provided no evidence of changes in value of dielectric constant that could indicate possible geologic discontinuities or stratification of physically diverse materials. We thus started a new investigation based on processing of raw MARSIS data. Here we report on the preliminary results of this study. We searched the MARSIS archive for raw data stored in flash memory. When operating with flash storage, the radar collects 2 frequency bands along-track covering a distance = 100-250 km, depending on the orbiter altitude [2]. We found flash memory data from 24 orbits over the area. We processed the data focusing radar returns in off-nadir directions, to maximize the likelihood of detecting sloping subsurface structures, including those striking parallel to the Mars Express sub-polar orbits. We plan to follow this study by applying a new processor aimed at improving the resolution and signal to noise ratio of the data. [1] Caprarelli et al. (2017), LPSC 48, 1720. [2] Watters et al. (2017), LPSC 48, 1693.

Collisional Ring Galaxies (RiGs), with their expanding ring of gas and stars and their high star formation rate are unique objects where to study the most massive products of star formation and shed some light on the nature of ultra luminous X-ray sources (ULXs) found on their rings. We have recently constructed the X-ray luminosity function of ULXs in RiGs which is mostly consistent with previous results but shows two bright objects at the highest luminosity above the extrapolation of previous models for ULXs. They could be the best cases of Intermediate Mass Black Holes, or further ULXs powered by neutron stars, or even something different (e.g Supernovae). We will describe in detail the RiGs and their properties and compare the derived XLF with previous results.

Measuring deuteration fraction in protostellar cores is considered as an important method for age determinations of protostellar cores, and the high deuteration fraction of up to 10% has been considered as evidence for high ages and strong support via magnetic field. In this talk, I will present 3D magneto-hydrodynamical simulations including the deuteration chemistry to explore how the deuteration fraction depends on the dynamical and chemical conditions. I will show that high deuteration fractions can be obtained under a large set of different conditions.

The optimization of the execution times of data analysis and theoretical simulation codes, combined with the ability to manage large amounts of data, and with the energy efficiency of all processes, are decisive ingredients for the success of large research projects in astrophysics. On the other hand, the new opportunities provided by computer science developments will also significantly change the "modus operandi" of many researchers. The creation of USC VIII, dedicated to high-performance computing and data archiving, therefore represents an invaluable opportunity to support INAF members and projects in the highly competitive current research landscape and in what will mature over the next decades. The presentation describes the context, the organizational methods, the short and medium term objectives, the available and planned resources of the newborn USC VIII, which also includes almost all the activities (for example cloud, networks, GARR, software licenses, and services research commons such as gitlab, etc.) previously conducted by the so-called INAF ICT. Emphasis is also given to collaborations with other organizations and above all with industries. The presentation also wants to represent an opportunity to stimulate dialogue and the sharing of experiences in the field of computing, archives, services and IT developments: an opportunity to receive suggestions from the community, to gather information about any problems in this sector which exist in any specific INAF headquarters, and to start the assembly of a list of the local expertise to be exploited in the creation of the INAF computing ecosystem.

KiDS is one of the VST ESO public survey and up to date it has been surveying 450 deg2 of the extragalactic sky.

The three equatorial regions of the Galaxy And Mass Assembly (GAMA) survey (G09, G12, and G15) overlap 180 deg2 surveyed by KiDS. The redshift distribution, for the >300k galaxies in the GAMA sample, ranges between z=0.003 and z=0.9,

with a median value of z=0.21 and a median signal-to-noise ratio SNR=7.3. A synergistic approach to combined photometric and spectroscopic data products allows us to investigate a large variety of science, e.g., from training neural networks for the photometric redshift estimation, to the study of dark matter fraction and scaling relations.

Therefore, we present the kinematic analysis of GAMA galaxy spectra, with the aim of measuring central velocity dispersions.

We made an intensive use of automatic routines which exploit the Penalized Pixel-Fitting method in order to fit the spectra in the restframe wavelength range 3850-6800 Å including in the window several strong absorption lines. We currently produced a velocity dispersion catalogue containing the 80% of the galaxies in the all the fields surveyed by GAMA (including the three overlapping with KiDS), and we present the statistical analysis of the results. We have additionally exploited KiDS and GAMA photometric databases in order to investigate the Faber-Jackson relation for a subsample of spheroid dominated galaxies in the equatorial fields G09, G12, and G15.

The 3CR catalogue is one of the best studied sample of radio-loud active galaxies, spanning a wide range of redshifts and radio powers and being unbiased with respect to X-ray observations. We are completing the Chandra Snapshot Survey of the 3CR catalog. Preliminary results on the extension of the X-ray observations in the 0.5-1 redshift range are presented here. We compared Chandra observations with radio maps to search for extended emission associated with jets, hotspots and galaxy clusters. We found the X-ray radiation arising from the intergalactic medium in one galaxy cluster and we detected three hostpots in the Chandra images. X-ray emission from the core of all radio galaxies in our sample was also found, seven of them also showing extended X-ray emission around their nuclei.

The birth of a Sun-like star is a complex game played by several participants whose respective roles are not yet entirely clear. On the one hand, the star-to-be accretes matter from a collapsing envelope. The gravitational energy released in the process heats up the material surrounding the protostar, creating warm regions enriched by interstellar complex organic molecules (iCOMs, at least 6 atoms) called hot-corinos. On the other hand, the presence of angular momentum and magnetic fields leads to two consequences: (i) the formation of circumstellar disks; and (ii) substantial episodes of matter ejection, as e.g. collimated jets.

Thanks to the combination of the high-sensitivities and high-angular resolu- tions provided by the advent of new telescopes such as ALMA and NOEMA, it is now possible to image in details the earliest stages of the Sun-like star formation, thus inspecting the inner ( < 50 AU from the protostar) jet. at these spatial scales a proper study of jets has to take into account also the effects connected with the accreting disk. In other words, it is time to study the protostellar jet-disk system as a whole. Several still unanswered questions can be addressed. What is the origin of the chemically enriched hot corinos: are they jet-driven shocked regions? What is the origin of the ejections: are they due to disk or stellar winds? Shocks are precious tool to attack these questions, given they enrich the gas phase with the species deposited onto the dust mantles and/or locked in the refractory dust cores. Basically, we have to deal with two kind of shocks: (i) high-velocity shocks produced by protostellar jets, and (ii) slow accretion shocks located close to the centrifugal barrier of the accretion disks. Both shocks are factories of iCOMs, which can be then efficiently used to follow both the kinematics and the chemistry of the inner protostellar systems. With this in mind, we will discuss recent results obtained in the framework of different observational campaigns at mm and sub-mm wavelengths.

The Cherenkov Telescope Array (CTA) will be the next generation gamma-ray observatory, open to the scientific community, to investigate the very high-energy emission from a large variety of celestial sources in the 20 GeV - 300 TeV energy range. The full array, distributed over two sites, one in the northern and one in the southern hemisphere, will provide whole-sky coverage and will improve the sensitivity with respect to the current major imaging atmospheric Cherenkov arrays (H.E.S.S., MAGIC and VERITAS) by a factor of five to twenty, depending on the energy. The large variety of science topics that CTA will investigate, from Galactic to extra-galactic sources up to fundamental physics, are addressed by means of nine Key Science Projects (KSPs) and one dark matter Programme. A particular emphasis will be put on major projects providing legacy data-sets, such as surveys and population studies, and the investigation of a few iconic classes of objects, such as gamma-ray bursts, clusters of galaxies, and cosmic accelerators. We review the current status of the CTA project, introducing the highlights from the telescope prototypes and discuss the main CTA Key Science Projects which will focus on those scientific cases that will greatly benefit from a multi-wavelength approach, involving the major facilities available at the time of the CTA scientific operations.

The Cherenkov Telescope Array (CTA) will be the next generation gamma-ray observatory, open to the scientific community, to investigate the very high-energy emission from a large variety of celestial sources in the 20 GeV - 300 TeV energy range. The full array, distributed over two sites, one in the northern and one in the southern hemisphere, will provide whole-sky coverage and will improve the sensitivity with respect to the current major arrays such as H.E.S.S., MAGIC and VERITAS by a factor of five to twenty, depending on the energy. CTA will investigate a much higher number of already known classes of sources, going to much larger distances in the Universe, performing population studies, accurate variability and spatially-resolved studies. Moreover, new light will be shed on new classes of TeV sources, such as GRBs and cluster of galaxies. Furthermore, by pushing the high-energy limit to E > 100 TeV, CTA will allow a thorough exploration of the cut-off regime of the cosmic accelerators. The search for an annihilation signature of dark matter in the Galactic halo and in prominent dwarf spheroidal galaxies is one of the most important goals of CTA. We review the current status of the CTA project, introducing the highlights from the telescope prototypes and discuss the main CTA Key Science Projects, which will focus on major scientific cases, allowing us to provide legacy data-sets of high value to a wider community.

The mass accretion rate is a crucial parameter for the study of the evolution of accretion discs around young low-mass stellar and substellar objects (YSOs), because it sets important constraints for disc evolution models and disc clearing mechanisms, and is a key quantity for the studies of Pre-Main Sequence (PMS) stellar evolution and planet formation. Low-mass PMS stars with transitional discs accreting at very low rates are likely in the final stages of inner disc evolution, and probably have already formed protoplanets. Hence, identifying and investigating such low accretors may help understanding planet formation. However, measurements of low accretion rates are challenging. In this work, we use UV-HST spectra to unambiguously confirm and investigate the accretion rate in the transitional YSO MYLup, an object previously classified as a weak or non-accretor based on optical spectra. The puzzle here is that the HST data provide a Macc value an order

The distribution over mass of stars at birth (the initial mass function, IMF) is one of the most important parameters in star-formation research. What determines the IMF is still not clear, nor is it clear whether the IMF is the same for every star forming region. It does seem, however, that the IMF is set very early on by the mass of the molecular cores out of which the stars form. The core mass function (CMF), and by consequence the IMF, may however depend on the physical and chemical properties of the environment. We present the results of our determination of the CMF at various locations in the Galactic star-forming complex NGC 6357. We used SCUBA2 at the JCMT to observe, at 450 mu and 850 mu, the dust associated with the molecular clouds in a 30′ x 30′ (15pc x 15pc) region containing three HII regions. We assess the radiative and mechanical influence of the stars that excite the HII regions on the molecular gas, by determining the CMF near the HII regions and comparing it with that in more quiescent (less exposed to intense stellar feedback) parts of the complex. Preliminary analysis suggests there is a difference between the CMFs.

Atmospheric phenomena of Mars can be highly dynamic and have daily and seasonal variations. Planetary-scale wavelike disturbances, for example, are frequently observed in Mars' polar winter atmosphere. Possible sources of the wave activity were suggested to be dynamical instabilities and quasi-stationary planetary waves, i.e. waves that arise predominantly via zonally asymmetric surface properties. For a comprehensive understanding of these phenomena, single layers of altitude have to be analyzed carefully and relations between different atmospheric quantities and interaction with the surface of Mars have to be considered. The CROSS DRIVE project tries to address the presentation of those data with a global view by means of virtual reality techniques. Complex orbiter data from spectrometer and observation data from Earth are combined with global circulation models and high-resolution terrain data and images available from Mars Express or MRO instruments. Scientists can interactively extract features from those dataset and can change visualization parameters in real-time in order to emphasize findings. Stereoscopic views allow for perception of the actual 3D behavior of Mars's atmosphere. A very important feature of the visualization system is the possibility to connect distributed workspaces together. This enables discussions between distributed working groups. The workspace can scale from virtual reality systems to expert desktop applications to web-based project portals. If multiple virtual environments are connected, the 3D position of each individual user is captured and used to depict the scientist as an avatar in the virtual world. The appearance of the avatar can also scale from simple annotations to complex avatars using tele-presence technology to reconstruct the users in 3D. Any change of the feature set (annotations, cutplanes, volume rendering, etc.) within the VR is immediately exchanged between all connected users. This allows that everybody is always aware of what is visible and discussed. The discussion is supported by audio and interaction is controlled by a moderator managing turn-taking presentations. A use case execution proved a success and showed the potential of this immersive approach.

We present a deep (μg ≍ 30 mag arcsec-2) surface photometry of NGC 1533, a barred early-type galaxy with an outer ring, situated in the east side of the Dorado group. The data were obtained with OmegaCAM@VST during the VEGAS surveys. Our surface photometry reveals the presence of an extended underlying disk in NGC 1533. Relevant asymmetries, arm-like structures and tails are detected in the galaxy both via un-sharp masking and by subtraction of galaxy model. The g-r color diagram and the color map suggest the presence of star formation regions at the inner edge of the ring, especially in the north side of the galaxy. These regions with UV features were already found with Swift-UVOT observations. Signatures of interaction between the NGC 1533, IC 2038 and IC 2039 are detected by our optical images. These signatures are in agreement with the HI map, that connects these three galaxies. Moreover these features seem to be the optical counterparts of the high-density regions of intragroup HI rings and arcs.