Search Publications
Characterizing southern portion of Mare Vaporum with improved Chandrayaan-1 M3 data
Videen, Gorden; Shkuratov, Yuriy; Surkov, Yehor +3 more
We investigate a southern portion of Mare Vaporum using Chandrayaan-1 M3 images for which we suppress striped noise. Additional data processing allows us to analyze such spectral parameters as the depths and positions of the absorption bands near 1 and 2 µm. Mineral types were mapped using the cluster analysis of Adams diagram for…
The disk-torus system in active galactic nuclei: possible evidence of highly spinning black holes
Celotti, Annalisa; Ghisellini, Gabriele; Sbarrato, Tullia +1 more
We study the ratio R between the luminosity of the torus and that of the accretion disk, inferred from the relativistic model KERRBB for a sample of approximately 2000 luminosity-selected radio-quiet Type I active galactic nuclei from the Sloan Digital Sky Survey catalog. We find a mean ratio R ≈ 0.8 and a considerable number of sources with R ≳ 1…
Measuring Young Stars in Space and Time. I. The Photometric Catalog and Extinction Properties of N44
Gennaro, Mario; Dolphin, Andrew E.; Klessen, Ralf S. +9 more
In order to better understand the role of high-mass stellar feedback in regulating star formation in giant molecular clouds, we carried out a Hubble Space Telescope (HST) Treasury Program Measuring Young Stars in Space and Time (MYSST) targeting the star-forming complex N44 in the Large Magellanic Cloud (LMC). Using the F555W and F814W broadband f…
τ9 Eri: a bright pulsating magnetic Bp star in a 5.95-d double-lined spectroscopic binary
Wade, G. A.; Pigulski, A.; Kochukhov, O. +2 more
τ9 Eri is a Bp star that was previously reported to be a single-lined spectroscopic binary. Using 17 ESPaDOnS spectropolarimetric (Stokes V) observations, we identified the weak spectral lines of the secondary component and detected a strong magnetic field in the primary. We performed orbital analysis of the radial velocities of both co…
The Araucaria Project: Deep Near-infrared Photometric Maps of Local and Sculptor Group Galaxies. I. Carina, Fornax, and Sculptor
Gieren, Wolfgang; Pietrzyński, Grzegorz; Pilecki, Bogumił +12 more
Deep near-infrared (NIR) J- and K-band photometry of three Local Group dwarf spheroidal galaxies—Fornax, Carina, and Sculptor—is made available for the community. Until now, these data have only been used by the Araucaria Project to determine distances using the tip of the red giant branch and RR Lyrae stars. Now, we present the entire data collec…
XMM Observation of the Supernova Remnant J0454-6713 and the Adjacent N9 Superbubble
Foster, Adam R.; Smith, Randall K.; Points, Sean D. +1 more
The Large Magellanic Cloud supernova remnant J0454-6713 abutting the H II region N9 has been observed with XMM-Newton. Two groups of lines from Fe XVII account for half the emission and lines from Fe XVIII, O VII, and O VIII are also clearly detected with the XMM RGS. Isothermal equilibrium fits of the EPIC spectra reproduce the basic spectral for…
Deriving physical parameters of unresolved star clusters. VI. Adaptive aperture photometry of the M31 PHAT star clusters
Stonkutė, Rima; Vansevičius, Vladas; Naujalis, Rokas
Context. This study is the sixth of a series that investigates degeneracy and stochasticity problems present in the determination of the age, mass, extinction, and metallicity of partially resolved or unresolved star clusters in external galaxies when using Hubble Space Telescope broadband photometry. In the fifth publication, it was noticed that …
The Effects of Magnetic Boundary on the Uniform Distribution of Energetic Particle Intensities Observed by Multiple Spacecraft
Wang, Yang; Lyu, Dan; Xiao, Boxi +1 more
In the decay phase of solar energetic particle (SEP) events, particle intensities observed by widely separated spacecraft usually present comparable intensities (within a factor of 2-3) that evolve similarly in time. The phenomenon of SEP events is called a reservoir, which could be observed frequently in intensive gradual SEP events. In this work…
A study of the long-term activity of five intermediate polars with accretion discs
Šimon, Vojtěch
Intermediate polars (IPs) are cataclysmic variables with mildly magnetized white dwarfs (WDs). This analysis of the long-term optical activity of five examples of IPs with accretion discs used data from the Catalina Real-time Transient Survey, Digital Access to a Sky Century @ Harvard (DASCH) and the American Association of Variable Star Observers…
Analysis of Time-Distance Helioseismology for Detection of Emerging Active Regions
Kosovichev, Alexander G.; Stefan, John T.; Stejko, Andrey M.
A time-distance helioseismic technique, similar to the one used by Ilonidis et al., is applied to two independent numerical models of subsurface sound-speed perturbations to determine the spatial resolution and accuracy of phase travel time shift measurements. The technique is also used to examine pre-emergence signatures of several active regions…