Morphological estimators on Sunyaev-Zel'dovich maps of MUSIC clusters of galaxies

The determination of the morphology of galaxy clusters has important repercussions for cosmological and astrophysical studies of them. In this paper, we address the morphological characterization of synthetic maps of the Sunyaev-Zel'dovich (SZ) effect for a sample of 258 massive clusters (Mvir> 5×1014h-1M⊙at z=0), extracted from theMUSIC hydrodynamical simulations. Specifically, we use five known morphological parameters (which are already used in X-ray) and two newly introduced ones, and we combine them in a single parameter. We analyse two sets of simulations obtained with different prescriptions of the gas physics (non-radiative and with cooling, star formation and stellar feedback) at four red shifts between 0.43 and 0.82. For each parameter, we test its stability and efficiency in discriminating the true cluster dynamical state, measured by theoretical indicators. The combined parameter is more efficient at discriminating between relaxed and disturbed clusters. This parameter had a mild correlation with the hydrostatic mass (~0.3) and a strong correlation (~0.8) with the offset between the SZ centroid and the cluster centre of mass. The latter quantity is, thus, the most accessible and efficient indicator of the dynamical state for SZ studiesThis work has been partially supported by funding from Sapienza University of Rome - Progetti di Ricerca Anno 2015 prot. C26A15LXNR. GY and FS acknowledge financial support from MINECO/FEDER under research grant AYA2015-63810-P. ER acknowledge financial contribution from the agreement ASI-INAF n 2017-14-H.

A concept mission for the Stellar Population and Evolution with Cubesats (SPEC)

Binary or multiple stellar systems, constituting almost a third of the content of the Milky Way, represent a high priority astronomical target due to their repercussions on the stellar dynamical and evolutionary parameters. Moreover the spectral study of such class of stars allows to better constrain the evolutionary theories of the Galactic stellar populations. By resolving the members of stellar systems through photometric observations we are able to perform more detailed measurements to infer their mass. In this paper we investigate the feasibility of a cubesat based mission including an optical payload to directly optically discriminate the members of a selected sample of binary systems. The scientific targets, consisting 11 M class dwarf stars binary systems, have been extracted from the already studied Riaz catalogue. These subset has been selected considering the star distance, the members angular separation, and the distance from the Galactic plane (due to limit the background and foreground contamination). The satellite concept is based on a 6 unit Cubesat embedding some commercial off the shelf components and an ad hoc designed optical payload occupying almost 4 units. The optical configuration has been chosen in order to fit the angular resolution requirements, as derived from the target characteristics. Moreover, according to the optical analysis and the computed field of view some requirements on the attitude control system have been inferred and fulfilled by the component selection. The paper is organized as in the following: a brief scientific introduction is made; consequently the project is described with particular attention to the optical design and the standard sub-systems; finally the conclusions are drawn and the future perspectives are investigated

The Three Hundred project: a large catalogue of theoretically modelled galaxy clusters for cosmological and astrophysical applications

We introduce the The Three Hundred project, an endeavour to model 324 large galaxy clusters with full-physics hydrodynamical re-simulations. Here we present the dataset and study the differences to observations for fundamental galaxy cluster properties and scaling relations. We find that the modelled galaxy clusters are generally in reasonable agreement with observations with respect to baryonic fractions and gas scaling relations at redshift z = 0. However, there are still some (model-dependent) differences, such as central galaxies being too massive, and galaxy colours (g − r) being bluer (about 0.2 dex lower at the peak position) than in observations. The agreement in gas scaling relations down to 1013 h−1M⊙ between the simulations indicates that particulars of the sub-grid modelling of the baryonic physics only has a weak influence on these relations. We also include – where appropriate – a comparison to three semi-analytical galaxy formation models as applied to the same underlying dark matter only simulation. All simulations and derived data products are publicly available

The Three Hundred project : A large catalogue of theoretically modelled galaxy clusters for cosmological and astrophysical applications

We introduce the THE THREE HUNDRED project, an endeavour to model 324 large galaxy clusters with full-physics hydrodynamical re-simulations. Here we present the data set and study the differences to observations for fundamental galaxy cluster properties and scaling relations. We find that the modelled galaxy clusters are generally in reasonable agreement with observations with respect to baryonic fractions and gas scaling relations at redshift z = 0. However, there are still some (model-dependent) differences, such as central galaxies being too massive, and galaxy colours (g − r) being bluer (about 0.2 dex lower at the peak position) than in observations. The agreement in gas scaling relations down to 1013h−1M⊙ between the simulations indicates that particulars of the sub-grid modelling of the baryonic physics only has a weak influence on these relations. We also include – where appropriate – a comparison to three semi-analytical galaxy formation models as applied to the same underlying dark-matter-only simulation. All simulations and derived data products are publicly available.Instituto de Astrofísica de La PlataFacultad de Ciencias Astronómicas y Geofísica

LEDSAT: A LED-Based CubeSat for optical orbit determination methodologies improvement

LEDSAT (LED-based small SATellite) is a 1-Unit CubeSat that will mount Light Emitting Diodes (LEDs) on its six faces, in order to validate, verify and improve the current methodologies for optical orbit determination. The LEDs will also support the CubeSat identification after deployment from the ISS. The satellite is being produced by the S5Lab research group at Sapienza - University of Rome, and it has been accepted for the European Space Agency Fly Your Satellite Programme. Currently, the on-board LEDs have been tested for the UV and gamma-ray radiations, proving their survivability in the space environment. This paper describes the aims, the design, the LED-based payload and the expected results of LEDSAT

Sapienza space debris observatory network (SSON): a high coverage infrastructure for space debris monitoring

Optical observations represent a passive method for space debris tracking and monitoring. Although being con- strained to limited time intervals, e.g. when the target is in sunlight and the observatory is in darkness, a debris observatory network distributed over multiple locations can improve the observational interval and favor the data integration for more consistent and significant results. The Sapienza Space Systems and Space Surveillance Laboratory (S5Lab) At Sapienza University of Rome has established Sapienza Space debris Observatory Net- work (SSON), an international network of optical observatories addressed at debris surveillance. The network is composed of six observatories owned and controlled by Sapienza, plus five observational sites controlled by collaborators (mainly University of Michigan and the University of Bern). The network operations have been carried out during several observations campaign, including the Tiangong-1 space station re-entry campaign per- formed in support of the Inter-Agency space Debris Committee (IADC). The heterogeneous capabilities of the different observatories represent an advantage for acquiring a wider set of debris monitoring data with different techniques. A strong synergy between our institution and the Italian specialized industry has also revealed to be very productive in the context of the network establishment. The present paper will describe the SSON infrastructure and the opportunities, improvements and future perspectives for research institutions or space industry of this wide observatories network will be discussed

Confirmation of NIKA2 investigation of the Sunyaev-Zel’dovich effect by using synthetic clusters of galaxies

The NIKA2 Sunyaev-Zel’dovich Large Program (SZLP) is focused on mapping the thermal SZ signal of a representative sample of selected Planck and ACT clusters spanning the redshift range 0.5 < z < 0.9. Hydrodynamical N-body simulations prove to be a powerful tool to endorse NIKA2 capabilities for estimating the impact of IntraCluster Medium (ICM) disturbances when re- covering the pressure radial profiles. For this goal we employ a subsample of objects, carefully extracted from the catalog Marenostrum MUltidark SImulations of galaxy Clusters (MUSIC), spanning equivalent redshift and mass ranges as the LPSZ. The joint analysis of real observations of the tSZ with NIKA2 and Planck enables to validate the NIKA2 pipeline and to estimate the ICM pressure profiles. Moreover, the possibility to identify a priori the dynamical state of the selected synthetic clusters allows us to verify the impact on the recovered ICM profile shapes and their scatters. Morphological analysis of maps of the Compton parameter seems to be a way to observationally segregate the sample based on the dynamical state in relaxed and disturbed synthetic clusters

Confirmation of NIKA2 investigation of the Sunyaev-Zel’dovich effect by using synthetic clusters of galaxies

The NIKA2 Sunyaev-Zel’dovich Large Program (SZLP) is focused on mapping the thermal SZ signal of a representative sample of selected Planck and ACT clusters spanning the redshift range 0.5 < z < 0.9. Hydrodynamical N-body simulations prove to be a powerful tool to endorse NIKA2 capabilities for estimating the impact of IntraCluster Medium (ICM) disturbances when re- covering the pressure radial profiles. For this goal we employ a subsample of objects, carefully extracted from the catalog Marenostrum MUltidark SImulations of galaxy Clusters (MUSIC), spanning equivalent redshift and mass ranges as the LPSZ. The joint analysis of real observations of the tSZ with NIKA2 and Planck enables to validate the NIKA2 pipeline and to estimate the ICM pressure profiles. Moreover, the possibility to identify a priori the dynamical state of the selected synthetic clusters allows us to verify the impact on the recovered ICM profile shapes and their scatters. Morphological analysis of maps of the Compton parameter seems to be a way to observationally segregate the sample based on the dynamical state in relaxed and disturbed synthetic clusters

Introductory note on Celano project

No Abstrac

Introductory note on Celano project

No Abstrac