Search Publications
Astrometric Calibration and Performance of the Dark Energy Camera
Benoit-Lévy, A.; Bechtol, K.; Smith, M. +54 more
We characterize the ability of the Dark Energy Camera (DECam) to perform relative astrometry across its 500 Mpix, 3-deg2 science field of view and across four years of operation. This is done using internal comparisons of ∼4 × 107 measurements of high signal-to-noise ratio stellar images obtained in repeat visits to fields of…
Instrumental response model and detrending for the Dark Energy Camera
Abbott, T. M. C.; Desai, S.; Gruen, D. +12 more
We describe the model for mapping from sky brightness to the digital output of the Dark Energy Camera (DECam) and the algorithms adopted by the Dark Energy Survey (DES) for inverting this model to obtain photometric measures of celestial objects from the raw camera output. This calibration aims for fluxes that are uniform across the camera field o…
Astrometry with Hubble Space Telescope Fine Guidance Sensors—A Review
Nelan, Edmund P.; Harrison, Thomas E.; Benedict, G. Fritz +1 more
Over the last 20 years, Hubble Space Telescope Fine Guidance Sensor interferometric astrometry has produced precise and accurate parallaxes of astrophysical interesting stars and mass estimates for stellar companions. We review parallax results, and binary star and exoplanet mass determinations, and compare a subset of these parallaxes with prelim…
Abundance Analyses of the New R Coronae Borealis Stars: ASAS-RCB-8 and ASAS-RCB-10
Kamath, Devika; Pandey, Gajendra; Kameswara Rao, N. +3 more
Abundance analyses of the two newly discovered R Coronae Borealis (RCB) stars ASAS-RCB-8 and ASAS-RCB-10 were conducted using high-resolution optical spectra and model atmospheres. Their chemical compositions place the pair among the majority class of RCBs. ASAS-RCB-10 is one of the most N-poor majority RCBs with an above average O abundance. Rela…
Performance of an Algorithm for Estimation of Flux, Background, and Location on One-dimensional Signals
Busonero, D.; Cancelliere, R.; Gai, M.
Optimal estimation of signal amplitude, background level, and photocenter location is crucial to the combined extraction of astrometric and photometric information from focal plane images, in particular from the one-dimensional measurements performed by Gaia on intermediate to faint magnitude stars. Our goal is to define a convenient maximum likel…
The Short-term Stability of a Simulated Differential Astrometric Reference Frame in the Gaia Era
Sozzetti, Alessandro; Abbas, Ummi; Bucciarelli, Beatrice +5 more
We use methods of differential astrometry to construct a small field inertial reference frame stable at the micro-arcsecond level. Such a high level of astrometric precision can be expected with the end-of-mission standard errors to be achieved with the Gaia space satellite using global astrometry. We harness Gaia measurements of field angles and …
Fundamental Parameters of the Eclipsing Binary TU Canis Majoris
Mennickent, R. E.; Garcés L., J.; Zharikov, S.
We present a spectroscopic and photometric study of the eclipsing binary TU Canis Majoris aimed to obtain their fundamental stellar parameters and evolutionary stage. Our results indicate that the masses, radii, temperatures, and luminosities for the primary and secondary stars are: {M}1=1.761+/- 0.012 {M}⊙ , {M}2=…
Photometric Strömgren-Hβ Quantification for O and B Stars of Luminosity Class V
Paunzen, Ernst; Kaltcheva, Nadia; Golev, Valeri
In any photometric system, the relationship between the spectral type and the intrinsic colors is fundamental for the photometric stellar classification and for a reliable derivation of stellar parameters. Such relationships are being constantly verified and improved based on larger and better samples. The capability of the Strömgren-Hβ photometry…