Search Publications
Doubts about the crucial role of the rising-tube mechanism in the formation of sunspot groups
Ishikawa, R.; Getling, A. V.; Buchnev, A. A.
Some preliminary processing results are presented for a dataset obtained with the Solar Optical Telescope on the Hinode satellite. The idea of the project is to record, nearly simultaneously, the full velocity and magnetic-field vectors in growing active regions and sunspot groups at a photospheric level. Our ultimate aim is to elaborate observati…
A study of the past dynamics of comet 67P/Churyumov-Gerasimenko with fast Lyapunov indicators
Guzzo, Massimiliano; Lega, Elena
Comet 67P/Churyumov-Gerasimenko is the target of the Rosetta mission. On the basis of backward numerical integrations of a large set of simulated comets whose initial conditions were obtained from small variations of the orbital parameters of comet 67P, and using the analysis of suitable chaos indicators, we detect the phase-space structure of the…
Stellar Populations and the Star Formation Histories of LSB Galaxies. V. WFC3 Color-Magnitude Diagrams
Schombert, James; McGaugh, Stacy
We present WFC3 observations of three low surface brightness (LSB) galaxies from the Schombert et al. LSB catalog that are within 11 Mpc of the Milky Way. Deep imaging at F336W, F555W, and F814W allow the construction of the V - I color-magnitude diagrams (CMD) to MI = -2. Overall 1869, 465, and 501 stellar sources are identified in the…
A Catalog of Point Sources Toward NGC 1333
Rebull, L. M.
I present a catalog of point-source objects toward NGC 1333, resolving a wide variety of confusion about source names (and occasionally positions) in the literature. I incorporate data from optical to radio wavelengths, but focus most of the effort on being complete and accurate from J (1.25 µm) to 24 µm. The catalog encompasses 52^\ci…
Spectral Imaging of Galaxy Clusters with Planck
Rasia, E.; Bourdin, H.; Mazzotta, P.
The Sunyaev-Zeldovich (SZ) effect is a promising tool for detecting the presence of hot gas out to the galaxy cluster peripheries. We developed a spectral imaging algorithm dedicated to the SZ observations of nearby galaxy clusters with Planck, with the aim of revealing gas density anisotropies related to the filamentary accretion of materials, or…
Sulphur-bearing species in molecular clouds
Bilalbegović, G.; Baranović, G.
We study several molecules that could help in the solution of the missing sulphur problem in dense clouds and circumstellar regions, as well as in the clarification of the sulphur chemistry in comets. These sulphur molecules are the trimer (CH2S)3 and the tetramer (CH2S)4 of thioformaldehyde, pentathian …
Ten years of Martian nitric oxide nightglow observations
Montmessin, Franck; Bertaux, Jean-Loup; Stiepen, Arnaud +2 more
We present 10 years of Martian NO nightglow Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars observations in limb and stellar occultation modes. The NO nightglow is used as a tracer of the summer-to-winter hemispherical circulation in the upper atmosphere of Mars. Its distribution roughly follows the curve latitude = -80…
Transition of an X-ray binary to the hard ultraluminous state in the blue compact dwarf galaxy VII Zw 403
Kaaret, P.; Feng, H.; Brorby, M.
We examine the X-ray spectra of VII Zw 403, a nearby low-metallicity blue compact dwarf (BCD) galaxy. The galaxy has been observed to contain an X-ray source, likely a high-mass X-ray binary (HMXB), with a luminosity of 1.3-23 × 1038 erg s-1 in the 0.3-8 keV energy range. A new Suzaku observation shows a transition to a lumin…
A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, δ Orionis Aa. I. Overview of the X-Ray Spectrum
Gull, T. R.; Corcoran, M. F.; Owocki, S. P. +22 more
We present an overview of four deep phase-constrained Chandra HETGS X-ray observations of δ Ori A. Delta Ori A is actually a triple system that includes the nearest massive eclipsing spectroscopic binary, δ Ori Aa, the only such object that can be observed with little phase-smearing with the Chandra gratings. Since the fainter star, δ Ori Aa2, has…
Nearly scale-invariant power spectrum and quantum cosmological perturbations in the gravity's rainbow scenario
Wang, Sai; Chang, Zhe
We propose the gravity's rainbow scenario as a possible alternative of the inflation paradigm to account for the flatness and horizon problems. We focus on studying the cosmological scalar perturbations which are seeded by the quantum fluctuations in the very early universe. The scalar power spectrum is expected to be nearly scale-invariant. We es…