Search Publications
The broad-band spectrum of the narrow-line Seyfert 1 NGC 4748: from UV to hard X-ray
Vasylenko, A. A.
We report the results obtained by a broad-band (0.5–500 keV) data analysis of narrow-line Seyfert 1 galaxy NGC 4748 observed with an XMM-Newton/PN, INTEGRAL/ISGRI and SWIFT/BAT telescopes. This galaxy has a soft X-ray excess that is typical for the class of narrow-line Seyfert 1. The question of the origin of soft excess in such objects is still u…
Detailed Regression Model of Plasma Sheet By
Petrukovich, A. A.; Lukin, A. S.
In a statistical model plasma sheet By primarily depends on interplanetary magnetic field (IMF) Byi and geodipole tilt τ. With 11 years of Geotail measurements we investigate a role of several other parameters with a linear regression model. Optimal averaging window of IMF input, maximizing correlation and regression coefficients, is fo…
Aliasing in the Radial Velocities of YZ Ceti: An Ultra-short Period for YZ Ceti c?
Robertson, Paul
Mid-to-late M stars are opportunistic targets for the study of low-mass exoplanets in transit because of the high planet-to-star radius ratios of their planets. Recent studies of such stars have shown that, like their early-M counterparts, they often host multi-resonant networks of small planets. Here, I reanalyze radial velocity measurements of Y…
Analysis and interpretation of inner-heliospheric SEP events with the ESA Standard Radiation Environment Monitor (SREM) onboard the INTEGRAL and Rosetta Missions
Sanahuja, Blai; Papaioannou, Athanasios; Anastasiadis, Anastasios +6 more
Using two heliospheric vantage points, we study 22 solar energetic particle (SEP) events, 14 of which were detected at both locations. SEP proton events were detected during the declining phase of solar cycle 23 (November 2003-December 2006) by means of two nearly identical Standard Radiation Environment Monitor (SREM) units in energies ranging be…
Solving non-LTE problems in rotational transitions using the Gauss-Seidel method and its implementation in the Atmospheric Radiative Transfer Simulator
Hartogh, P.; Yamada, T.; Rezac, L. +3 more
This article presents our implementation of a non-LTE solver in spherical symmetry for molecular rotational transition in static or expanding atmospheres. The new open-source code relies on the Gauss-Seidel Accelerated Lambda Iteration methodology that provides a rapid and accurate convergence of the non-LTE problems, which is now routinely used i…
Chandra X-Ray Observatory and Hubble Space Telescope Observations of the Intermediate-age Cluster GLIMPSE-C01
Kargaltsev, Oleg; Hare, Jeremy; Rangelov, Blagoy
We report the results of Hubble Space Telescope and Chandra X-Ray Observatory observations of the GLIMPSE-C01 (hereafter GC01) star cluster. Color-magnitude and color-color diagrams suggest a cluster age of ≳2 Gyr up to ∼10 Gyr (dependent on GC01's metallicity), a distance of 3.3-3.5 kpc, and strong differential reddening with A V = 1…
Study of central light concentration in nearby galaxies
Ravikumar, C. D.; Aswathy, S.
We propose a novel technique to estimate the masses of supermassive black holes (SMBHs) residing at the centres of massive galaxies in the nearby Universe using simple photometry. Aperture photometry using SEXTRACTOR is employed to determine the central intensity ratio (CIR) at the optical centre of the galaxy image for a sample of 49 nearby galax…
PACS and SPIRE range spectroscopy of cool, evolved stars
Decin, L.; Lombaert, R.; Groenewegen, M. A. T. +3 more
Context. At the end of their lives AGB stars are prolific producers of dust and gas. The details of this mass-loss process are still not understood very well. Herschel PACS and SPIRE spectra which cover the wavelength range from ∼55 to 670 µm almost continuously, offer a unique way of investigating properties of AGB stars in general and the …
Photometric Modeling and VIS-IR Albedo Maps of Dione From Cassini-VIMS
Buratti, B. J.; Clark, R. N.; Stephan, K. +6 more
We report about visible and infrared albedo maps and spectral indicators of Dione's surface derived from the complete Visual and Infrared Mapping Spectrometer (VIMS) data set acquired between 2004 and 2017 during the Cassini tour in Saturn's system. Maps are derived by applying a photometric correction necessary to disentangle the intrinsic albedo…
Impact of quasar proper motions on the alignment between the International Celestial Reference Frame and the Gaia reference frame
Zhu, Z.; Liu, J. -C.; Malkin, Z.
The International Celestial Reference Frame (ICRF) is currently realized by the very long baseline interferometry (VLBI) observations of extragalactic sources with the zero proper motion assumption, while Gaia will observe proper motions of these distant and faint objects to an accuracy of tens of microarcseconds per year. This paper investigates …