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Related papers: ACTIN: A tool to calculate stellar activity indice…

200 papers

TIM (The Interactive METATOY) is a ray-tracing program specifically tailored towards our research in METATOYs, which are optical components that appear to be able to create wave-optically forbidden light-ray fields. For this reason, TIM…

The All-Sky Automated Survey (ASAS) appeared to be extremely useful in establishing the census of bright variable stars in the sky. A short review of the characteristics of the ASAS data and discoveries based on these data and related to…

Solar and Stellar Astrophysics · Physics 2015-06-17 Andrzej Pigulski

A bar-like central feature is commonly observed in both nearby and distant spiral-type galaxies, including the Milky Way. While many methods exist to categorise this morphology, no one method has emerged as the field-wide standard. To…

Astrophysics of Galaxies · Physics 2026-04-22 Elizabeth J. Iles , Finn A. Pal , Joss Bland-Hawthorn , Ken Freeman

We present the first results of a program to identify so far unknown active nuclei (AGN) in galaxies. Candidate galactic nuclei have been selected for optical spectroscopy from a cross-correlation of the ROSAT All Sky Survey (RASS) bright…

Astrophysics · Physics 2007-05-23 W. Pietsch , Th. Boller , S. Doebereiner , H. -U. Zimmermann , K. Bischoff , W. Kollatschny

Human activity recognition based on the computer vision is the process of labelling image sequences with action labels. Accurate systems for this problem are applied in areas such as visual surveillance, human computer interaction and video…

Computer Vision and Pattern Recognition · Computer Science 2014-08-15 Jay Prakash Gupta , Pushkar Dixit , Nishant Singh , Vijay Bhaskar Semwal

We present a convenient, all-in-one framework for the scientific analysis of fully reduced, (integral-field) spectroscopic data. The GIST pipeline (Galaxy IFU Spectroscopy Tool) is entirely written in Python3 and conducts all steps from the…

We present feasibility studies to directly image stellar surface features, which are caused by magnetic activity, with the Very Large Telescope Interferometer (VLTI). We concentrate on late type magnetically active stars, for which the…

Astrophysics · Physics 2009-11-07 M. Wittkowski , M. Schoeller , S. Hubrig , B. Posselt , O. von der Luehe

Radial velocities (RVs) measured from high-resolution stellar spectra are routinely used to detect and characterise orbiting exoplanet companions. The different lines present in stellar spectra are created by several species, which are…

Aims: Stellar activity may complicate the analysis of high-precision radial-velocity spectroscopic data when looking for exoplanets signatures. We aim at quantifying the impact of stellar spots on stars with various spectral types and…

Astrophysics · Physics 2009-11-13 Morgan Desort , Anne-Marie Lagrange , Franck Galland , Stephane Udry , Michel Mayor

Accurately modeling effects from stellar activity is a key step in detecting radial velocity signals of low-mass and long-period exoplanets. Radial velocities from stellar activity are dominated by magnetic active regions that move in and…

Earth and Planetary Astrophysics · Physics 2020-01-08 Chantanelle Nava , Mercedes López-Morales , Raphaëlle D. Haywood , Helen A. C. Giles

In a series of papers based on the FIRST and Sloan Digital Sky Surveys (SDSS), we investigate the local population of star-forming galaxies and Active Galactic Nuclei (AGN) in order to clarify the link between these two types of activity,…

Cosmology and Nongalactic Astrophysics · Physics 2009-03-25 Pietro M. Reviglio , David J. Helfand

Wind-driving in asymptotic giant branch (AGB) stars is commonly attributed to a two-step process. First, matter in the stellar atmosphere is levitated by shock waves, induced by stellar pulsation, and second, this matter is accelerated by…

Solar and Stellar Astrophysics · Physics 2017-09-27 S. Liljegren , S. Höfner , K. Eriksson , W. Nowotny

Stellar activity cycles are the manifestation of dynamo process running in the stellar interiors. They have been observed during years to decades thanks to the measurement of stellar magnetic proxies at the surface of the stars such as the…

Solar and Stellar Astrophysics · Physics 2015-06-12 S. Mathur , R. A. Garcia , A. Morgenthaler , D. Salabert , P. Petit , J. Ballot , C. Regulo , C. Catala

We present the Active Galactic Nuclei (AGN) classifier as currently implemented within the Fink broker. Features were built upon summary statistics of available photometric points, as well as color estimation enabled by symbolic regression.…

Instrumentation and Methods for Astrophysics · Physics 2022-11-22 Etienne Russeil , Emille E. O. Ishida , Roman Le Montagner , Julien Peloton , Anais Moller

Fast, massive winds are ubiquitously observed in the UV and X-ray spectra of Active Galactic Nuclei (AGN) and other accreting sources. Theoretical and observational evidences suggest they are launched at accretion disc scales, carrying…

High Energy Astrophysical Phenomena · Physics 2024-10-23 Alfredo Luminari , Enrico Piconcelli , Francesco Tombesi , Fabrizio Nicastro , Fabrizio Fiore

The Spitzer Space Telescope and in particular its InfraRed Array Camera (IRAC) is an ideal facility to study the distribution of AGB stars in our own and other galaxies because of its efficiency in surveying vast areas of the sky and its…

Astrophysics · Physics 2007-05-23 M. Marengo , J. L. Hora , P. Barmby , S. P. Willner , L. E. Allen , M. T. Schuster , G. G. Fazio

Active Galactic Nuclei (AGN) are powerful astronomical objects with very high luminosities. Theoretical arguments suggest that these objects are capable of accelerating particles to energies of 10$^{20}$ eV. In environments with matter or…

High Energy Astrophysical Phenomena · Physics 2023-07-31 Sreetama Goswami

We present medium resolution (R approx. 1500) ISO-SWS 2.4--45 micron spectra of a sample of 29 galaxies with active nuclei. This data set is rich in fine structure emission lines tracing the narrow line regions and (circum-)nuclear star…

Astrophysics · Physics 2009-11-07 E. Sturm , D. Lutz , A. Verma , H. Netzer , A. Sternberg , A. F. M. Moorwood , E. Oliva , R. Genzel

We have compiled a large sample of low-redshift active galactic nuclei (AGN) identified via their emission line characteristics from the spectroscopic data of the Sloan Digital Sky Survey. Since emission lines are often contaminated by…

We have studied the star-formation and AGN activity of massive galaxies in the redshift range $z=0.4-2$, which are detected in a deep survey field using the AKARI InfraRed (IR) astronomical satellite and {\em Subaru} telescope toward the…