Examinando por Autor "Mahlke, M."

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Acceso Abierto
Asteroid phase curves from ATLAS dual-band photometry
(Elsevier BV, 2020-09-19) Mahlke, M.; Carry, B.; Denneau, L.; National Aeronautics and Space Administration (NASA); Agencia Estatal de Investigación (AEI); Mahlke, M. [0000-0003-2831-0513]
Asteroid phase curves are used to derive fundamental physical properties through the determination of the absolute magnitude H. The upcoming visible Legacy Survey of Space and Time (LSST) and mid-infrared Near-Earth Object Surveillance Mission (NEOSM) surveys rely on these absolute magnitudes to derive the colours and albedos of millions of asteroids. Furthermore, the shape of the phase curves reflects their surface compositions, allowing for conclusions on their taxonomy. We derive asteroid phase curves from dual-band photometry acquired by the Asteroid Terrestrial-impact Last Alert System telescopes. Using Bayesian parameter inference, we retrieve the absolute magnitudes and slope parameters of 127,012 phase curves of 94,777 asteroids in the photometric H, G1, G2- and H, G12∗-systems. The taxonomic complexes of asteroids separate in the observed G1, G2-distributions, correlating with their mean visual albedo. This allows for differentiating the X-complex into the P-, M-, and E-complexes using the slope parameters as alternative to albedo measurements. Further, taxonomic misclassifications from spectrophotometric datasets as well as interlopers in dynamical families of asteroids reveal themselves in G1, G2-space. The H, G12∗-model applied to the serendipitous observations is unable to resolve target taxonomy. The G1, G2 phase coefficients show wavelength-dependency for the majority of taxonomic complexes. Their values allow for estimating the degree of phase reddening of the spectral slope. The uncertainty of the phase coefficients and the derived absolute magnitude is dominated by the observational coverage of the opposition effect rather than the magnitude dispersion induced by the asteroids' irregular shapes and orientations. Serendipitous asteroid observations allow for reliable phase curve determination for a large number of asteroids. To ensure that the acquired absolute magnitudes are suited for colour computations, it is imperative that future surveys densely cover the opposition effects of the phase curves, minimizing the uncertainty on H. The phase curve slope parameters offer an accessible dimension for taxonomic classification, correlating with the albedo and complimentary to the spectral dimension.
Restringido
Identification of asteroids using the Virtual Observatory: the WFCAM Transit Survey
(Oxford Academics: Oxford University Press, 2019-10-26) Cortés Contreras, M.; Jiménez Esteban, F. M.; Mahlke, M.; Solano, Enrique; Durech, J.; Barceló Forteza, S.; Rodrigo, C.; Velasco, A.; Carry, B.; Agencia Estatal de Investigación (AEI); European Space Agency (ESA); Contreras, M. [0000-0003-3734-9866]; Rodrigo Blanco, C. [0000-0001-6068-0077]; Jiménez Esteban, F. M. [0000-0002-6985-9476]; Carry, B. [0000-0001-5242-3089]; Solano, E. [0000-0003-1885-5130]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The nature and physical properties of asteroids, in particular those orbiting in the near-Earth space, are of scientific interest and practical importance. Exoplanet surveys can be excellent resources to detect asteroids, both already known and new objects. This is due to their similar observing requirements: large fields of view, long sequences, and short cadence. If the targeted fields are not located far from the ecliptic, many asteroids will cross the field of view occasionally. We present two complementary methodologies to identify asteroids serendipitously observed in large-area astronomical surveys. One methodology focuses on detecting already known asteroids using the Virtual Observatory tool SkyBoT, which predicts their positions and motions in the sky at a specific epoch. The other methodology applies the ssos pipeline, which is able to identify known and new asteroids based on their apparent motion. The application of these methods to the 6.4 deg2 of the sky covered by the Wide-Field CAMera Transit Survey in the J-band is described. We identified 15 661 positions of 1821 different asteroids. Of them, 182 are potential new discoveries. A publicly accessible online, Virtual Observatory compliant catalogue was created. We obtained the shapes and periods for five of our asteroids from their light curves built with additional photometry taken from external archives. We demonstrated that our methodologies are robust and reliable approaches to find, at zero cost of observing time, asteroids observed by chance in astronomical surveys. Our future goal is to apply them to other surveys with adequate temporal coverage.
Restringido
The Gran Telescopio Canarias OSIRIS broad-band first data release
(Oxford Academics: Oxford University Press, 2020-01-05) Cortés Contreras, M.; Bouy, H.; Solano, Enrique; Mahlke, M.; Jiménez Esteban, F. M.; Alacid, J. M.; Rodrigo, C.; European Space Agency (ESA); Agencia Estatal de Investigación (AEI); European Research Council (ERC); Cortés Contreras, M. [0000-0003-3734-9866]; Rodrigo, C. [0000-0001-6068-0077]; Solano, E. [0000-0003-1885-5130]; Jiménez Esteban, F. M. [0000-0002-6985-9476]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We present the first release of GTC OSIRIS broad-band data archive. This is an effort conducted in the framework of the Spanish Virtual Observatory to help optimize science from the Gran Telescopio Canarias Archive. Data Release 1 includes 6788 broad-band images in the Sloan griz filters obtained between 2009 April and 2014 January and the associated catalogue with roughly 6.23 million detections of more than 630 000 unique sources. The catalogue contains standard PSF and Kron aperture photometry with a mean accuracy better than 0.09 and 0.15 mag, respectively. The relative astrometric residuals are always better than 30 mas and better than 15 mas in most cases. The absolute astrometric uncertainty of the catalogue is of 0.12 arcsec. In this paper we describe the procedure followed to build the image archive and the associated catalogue, as well as the quality tests carried out for validation. To illustrate some of the scientific potential of the catalogue, we also provide two examples of its scientific exploitation: discovery and identification of asteroids and cool dwarfs.