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Stellar population astrophysics (SPA) with the TNG. Characterization of the young open cluster ASCC 123
Vallenari, A.; Sordo, R.; Bragaglia, A. +10 more
Star clusters are crucial to understanding stellar and Galactic evolution. ASCC 123 is a little-studied, nearby, and very sparse open cluster. We performed the first high-resolution spectroscopic study of this cluster in the framework of the Stellar Population Astrophysics (SPA) project with GIARPS at the TNG. We observed 17 stars, 5 of which turn…
Compton-thick AGNs in the NuSTAR Era. V. Joint NuSTAR and XMM-Newton Spectral Analysis of Three “Soft-gamma” Candidate CT-AGNs in the Swift/BAT 100-month Catalog
Comastri, A.; Ajello, M.; La Parola, V. +3 more
We present the joint NuSTAR and XMM-Newton spectral analysis in the 0.6-70 keV band of three candidate Compton-thick (CT-) active galactic nuclei (AGNs) selected in the 100-month Swift-BAT catalog. These objects were previously classified as CT-AGNs based on low-quality Swift-X-ray Telescope (XRT) and Swift-Burst Alert Telescope (BAT) data, and ha…
The Warm Gaseous Disk and the Anisotropic Circumgalactic Medium of the Milky Way
Bregman, Joel N.; Qu, Zhijie
Warm ({log}T≈ 5) gas is an important gaseous component in the galaxy baryonic cycle, which is important for understanding both gas accretion and galactic feedback processes. We built a two-dimensional disk-circumgalactic medium (CGM) model to study the warm gas distribution of the Milky Way (MW) using the absorption-line surveys of Si IV and O VI.…
Photometric Determination of the Mass Accretion Rates of Pre-main-sequence Stars. VI. The Case of LH 95 in the Large Magellanic Cloud
Panagia, Nino; Beccari, Giacomo; De Marchi, Guido +1 more
We report on the accretion properties of low-mass stars in the LH 95 association within the Large Magellanic Cloud. Using noncontemporaneous wideband optical and narrowband Hα photometry obtained with the Hubble Space Telescope, we identify 245 low-mass pre-main-sequence (PMS) candidates showing Hα excess emission above the 4σ level. We derive the…
Horizontal branch morphology: A new photometric parametrization
Salaris, M.; Fontana, A.; Castellani, M. +8 more
Context. Theory and observations indicate that the distribution of stars along the horizontal branch of Galactic globular clusters mainly depends on the metal content. However, the existence of globular clusters with similar metal content and absolute age but different horizontal branch morphologies, suggests the presence of another parameter affe…
Projection effects in galaxy cluster samples: insights from X-ray redshifts
Lovisari, L.; Pacaud, F.; Ramos-Ceja, M. E. +3 more
Presently, the largest sample of galaxy clusters selected in X-rays comes from the ROSAT All-Sky Survey (RASS). Although there have been many interesting clusters discovered with the RASS data, the broad point spread function of the ROSAT satellite limits the attainable amount of spatial information for the detected objects. This leads to the disc…
Comet 67P/Churyumov-Gerasimenko rotation changes derived from sublimation-induced torques
Jorda, L.; Kührt, E.; Keller, H. U. +3 more
Context. The change in rotation period and the orientation of the rotation axis of comet 67P/Churyumov-Gerasimenko (67P) can be deduced with high precision from images taken by the scientific imaging instruments on board the Rosetta mission. Non-gravitational forces are a natural explanation for these data.
Aims: We describe observed changes …
A Search for Intermediate-separation Low-mass Binaries in the Orion Nebula Cluster
Reiter, Megan; Greenbaum, Alexandra; Meyer, Michael R. +3 more
We present the results of a binary population study in the Orion Nebula Cluster (ONC) using archival Hubble Space Telescope (HST) data obtained with the Advanced Camera for Surveys in Johnson V filter (HST Proposal 10246, PI M. Robberto). Young clusters and associations hold clues to the origin and properties of multiple star systems. Binaries wit…
Searching for the Donor Stars of ULX Pulsars
Harrison, F. A.; Stern, D.; Brightman, M. +3 more
We report on our search for the optical counterparts of two ultraluminous X-ray pulsars with known orbital periods, M82 X-2 and NGC 5907 X-1, in new and archival Hubble Space Telescope observations, in an effort to characterize the donor stars in these systems. We detect five near-infrared sources consistent with the position of M82 X-2 that are t…
The 3D Kinematics of Gas in the Small Magellanic Cloud
Murray, Claire E.; Peek, J. E. G.; McClure-Griffiths, N. M. +3 more
We investigate the kinematics of neutral gas in the Small Magellanic Cloud (SMC) and test the hypothesis that it is rotating in a disk. To trace the 3D motions of the neutral gas distribution, we identify a sample of young, massive stars embedded within it. These are stars with radial velocity measurements from spectroscopic surveys and proper mot…