A5072079692- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Gamma-ray bursts and supernovae
- Particle Detector Development and Performance
- Calibration and Measurement Techniques
- Astrophysics and Cosmic Phenomena
- Superconducting and THz Device Technology
- History and Developments in Astronomy
- Classical Studies and Legal History
- Nuclear Physics and Applications
- Advanced X-ray Imaging Techniques
- Molecular Spectroscopy and Structure
- Spectroscopy and Laser Applications
- Geophysics and Gravity Measurements
- X-ray Spectroscopy and Fluorescence Analysis
- Atmospheric Ozone and Climate
- Adaptive optics and wavefront sensing
- Medical Imaging Techniques and Applications
- Scientific Measurement and Uncertainty Evaluation
- Galaxies: Formation, Evolution, Phenomena
Osservatorio Astronomico di Palermo
2014-2024
Physical Research Laboratory
2024
University of Maryland, Baltimore County
2024
National Institute for Astrophysics
2004-2023
Institut d'Histoire du Droit Jean Gaudemet
2017-2022
University of Palermo
1999-2018
Institute for Space Astrophysics and Planetology
2018
Istituto di Astrofisica Spaziale e Fisica cosmica di Palermo
2011-2015
Athena Group (United States)
2012
California Institute of Technology
2009
We present the results of a new study on relationship between coronal X-ray emission and stellar rotation in late-type main-sequence stars. have selected sample 259 dwarfs range 0.5–2.0, including 110 field stars 149 members Pleiades, Hyades, α Persei, IC 2602 2391 open clusters. All been observed with ROSAT, most them photometrically-measured periods available. Our confirm that two regimes exist, one which period is good predictor total luminosity, other constant saturated to bolometric...
We use the data of Chandra Orion Ultradeep Project (COUP) to study nearly 600 X-ray sources that can be reliably identified with optically well characterized T Tauri stars (TTS) in Nebula Cluster. detect emission from more than 97% visible late-type (spectral types F M) cluster stars. This proofs there is no ``X-ray quiet'' population suppressed magnetic activity. All TTS known rotation periods lie saturated or super-saturated regime relation between activity and Rossby numbers seen for...
We present a description of the data reduction methods and derived catalog more than 1600 X-ray point sources from exceptionally deep January 2003 Chandra Observatory observation Orion Nebula Cluster embedded populations around OMC-1. The was obtained with Chandra's Advanced CCD Imaging Spectrometer (ACIS) has been nicknamed Ultradeep Project (COUP). With an 838 ks exposure made over continuous period 13.2 days, COUP provides most uniform comprehensive dataset on emission normal stars ever...
We have analyzed a number of intense X-ray flares observed in the Chandra Orion Ultradeep Project (COUP), 13 days observation Nebula Cluster (ONC). Analysis flare decay allows to determine size, peak density and magnetic field flaring structure. A total 32 events (the most powerful 1% COUP flares), sufficient statistics for analysis. broad range times (from 10 400 ks) are present sample. Peak temperatures often very high, with half sample showing excess 100 MK. Significant sustained heating...
We have developed a method based on wavelet transforms (WTs) to detect sources in astronomical images obtained with photon-counting detectors, such as X-ray images. The WT is multiscale transform that suitable for detection and analysis of interesting image features (sources) spanning range sizes. This property the particularly well suited case which point-spread function strongly varying across image, it also effective extended sources. allows one measure source count rates, sizes,...
The X-ray Integral Field Unit (X-IFU) on board the Advanced Telescope for High-ENergy Astrophysics (Athena) will provide spatially resolved high-resolution spectroscopy from 0.2 to 12 keV, with 5 arc second pixels over a field of view minute equivalent diameter and spectral resolution 2.5 eV up 7 keV. In this paper, we first review core scientific objectives Athena, driving main performance parameters X-IFU, namely resolution, view, effective area, count rate capabilities, instrumental...
view Abstract Citations (258) References (44) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Einstein Observatory Coronal Temperatures of Late-Type Stars Schmitt, J. H. M. ; Collura, A. Sciortino, S. Vaiana, G. Harnden, F. R., Jr. Rosner, R. The results are presented a survey the coronal temperatures late-type stars using IPC. spectral analysis shows that frequently found one- and two-temperature descriptions mainly influenced by SNR data models continuous...
view Abstract Citations (206) References (139) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Einstein X-Ray Observatory Catalog of O-Type Stars Chlebowski, T. ; Harnden, F. R., Jr. Sciortino, S. Soft X-ray (0.2-3.5 keV) measurements for all normal, massive, O-type stars surveyed with the are presented as a catalog containing 89 detections and 176 upper bounds, together detailed discussion reduction process. Among 42 newly identified sources, several...
view Abstract Citations (99) References (41) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Einstein X-ray survey of the Pleiades : dependence emission on stellar age. Micela, G. ; Sciortino, S. Serio, Vaiana, Bookbinder, J. Golub, L. Harnden, F. R., Jr. Rosner, R. The data obtained with two pointed observations 1 deg by fields region have been analyzed, and results are presented. maximum-likelihood luminosity functions for G K stars in cluster derived, it...
Testing whether close-in massive exoplanets (hot Jupiters) can enhance the stellar activity in their host primary is crucial for models of and planetary evolution. Among systems with hot Jupiters, HD 189733 one best studied because its proximity, strong activity, presence a transiting planet, which allows transmission spectroscopy measure radius density. Here we report on X-ray star, A, using new XMM-Newton observation comparison previous observations. The spectrum quiescent intervals...
Hot Jupiters are subject to strong irradiation from the host stars and, as a consequence, they do evaporate. They can also interact with parent by means of tides and magnetic fields. Both phenomena have implications for evolution these systems. Here we present time resolved spectroscopy HD~189733 observed Cosmic Origin Spectrograph (COS) on board HST. The star has been during five consecutive HST orbits, starting at secondary transit planet ($\phi$ ~0.50-0.63). Two main episodes variability...
The X-ray properties of twenty ~1 Myr old O, B, and A stars the Orion Trapezium are examined with data from Chandra Ultradeep Project (COUP). On basis simple theories for emission, we define two classes separated at spectral type B4: hotter have strong winds that may give rise to emission in small- or large-scale wind shocks, cooler should be dark due their weaker absence outer convection zones where dynamos can generate magnetic fields. Only massive show exclusively constant soft-spectrum...
Using the results of our first paper on Chandra HRC observation Orion Nebula Cluster (ONC), here we explore relation between coronal activity its 1-Myr-old pre-main sequence population and stellar parameters. We find that median X-ray luminosities low mass stars (M/M_sun < 3) increase with increasing decreasing age. Brown dwarfs (0.03 M/M_sun 0.08) follow same trend mass. From M~0.1 to M~0.5M_sun, L_X/L_bol values by about half an order magnitude then remain constant at ~10^-3.5 for range...
Aims.This paper's goal is to improve the member census of NGC 2264 star-forming region and study origin X-ray activity in young PMS stars.
view Abstract Citations (134) References (57) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Einstein Observatory Survey of X-Ray Emission from Solar-Type Stars: The Late F and G Dwarf Stars Maggio, A. ; Sciortino, S. Vaiana, G. Majer, P. Bookbinder, J. Golub, L. Harnden, F. R., Jr. Rosner, R. Results a volume-limited X-ray survey stars luminosity classes IV V in the spectral range F7-G9 observed with are presented. Using survival analysis techniques,...
We report on the analysis of Chandra-ACIS data O, B, and WR stars in young association Cyg OB2. X-ray spectra 49 O-stars, 54 B-stars, 3 WR-stars are analyzed for brighter sources, epoch dependence fluxes is investigated. The O-stars OB2 follow a well-defined scaling relation between their bolometric luminosities: . This excellent agreement with one previously derived Carina OB1 association. Except brightest O-star binaries, there no general overluminosity due to colliding winds binaries....
The Athena mission entered a redefinition phase in July 2022, driven by the imperative to reduce cost at completion for European Space Agency below an acceptable target, while maintaining flagship nature of its science return. This notably called complete redesign X-ray Integral Field Unit (X-IFU) cryogenic architecture towards simpler active cooling chain. Passive via successive radiative panels spacecraft level is now used provide 50 K thermal environment X-IFU owned cryostat. 4.5 achieved...
We have for the first time detected X-ray emission associated with a protostellar jet, on jet emanating from L1551 IRS5 protostar. The protostar is hidden behind very large absorbing column density, making direct observation of jet's possible. observed likely shock "working surface", i.e. interface between and circumstellar medium. luminosity is, at erg s-1, significant fraction normally coronal young stars. spectrum compatible thermal hot plasma, temperature 4 MK, higher than expected (on...
We apply to the specific case of images taken with ROSAT PSPC detector our wavelet-based X-ray source detection algorithm presented in a companion paper. Such are characterized by presence "ribs," strongly varying point-spread function, and vignetting, so that their analysis provides challenge for any algorithm. First, we simulated flat background, as seen PSPC, order calibrate number spurious detections function significance threshold ascertain spatial distribution is uniform, i.e.,...
Context.The observation of young stars with circumstellar disks suggests that the are dissipated, starting from inner region, by radiation central star and eventually formation rocky planetesimals, over a time scale several million years. It was also shown strong UV emitted nearby massive can heat disk up to some thousand degrees, inducing photoevaporation gas. This process strongly reduces dissipation scale.
view Abstract Citations (116) References (84) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS ROSAT Observations of the Pleiades. I. X-Ray Characteristics a Coeval Stellar Population Micela, G. ; Sciortino, S. Kashyap, V. Harnden, F. R., Jr. Rosner, R. We report results deep X-ray survey core region Pleiades carried out with ROSA T. In single PSPC field (∼1° radius), we detect 99 214 stars, and compute upper limits for remainder. have detected all early dM...
Aims.The aim of this work is to identify the so far unknown low mass stellar population ~2 Myr old Cygnus OB2 star forming region, and investigate X-ray near-IR properties its members.