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Register a new userThe Mauna Kea Observatories Near-Infrared Filter Set. II. Specifications for a New JHKLM Filter Set for Infrared Astronomy
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We present a description of a new 1--5 $mu$m filter set similar to the long-used JHKLM filter set derived from that of Johnson. The new Mauna Kea Observatories Near-Infrared (MKO-NIR) filter set is designed to reduce background noise, improve photometric transformations from observatory to observatory, provide greater accuracy in extrapolating to zero air mass, and reduce the color dependence in the extinction coefficient in photometric reductions. We have also taken into account the requirements of adaptive optics in setting the flatness specification of the filters. A complete technical description is presented to facilitate the production of similar filters in the future.
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The isophotal wavelengths, flux densities, and AB magnitudes for Vega (alpha Lyr) are presented for the Mauna Kea Observatories near-infrared filter set. We show that the near-infrared absolute calibration for Vega determined by Cohen et al. and Megessier are consistent within the uncertainties, so that either absolute calibration may be used.
We present Land M photometry, obtained at UKIRT using the Mauna Kea Observatories Near-IR filter set, for 46 and 31 standard stars, respectively. The L standards include 25 from the UKIRT in-house Bright Standards with magnitudes deriving from Elias et al. (1982) and observations at the IRTF in the early 1980s, and 21 fainter stars. The M magnitudes derive from the results of Sinton & Tittemore (1984). We estimate the average external error to be 0.015 mag for the bright L standards and 0.025 mag for the fainter L standards, and 0.026 mag for the M standards. The new results provide a network of homogeneously observed standards, and establish reference stars for the MKO system, in these bands. They also extend the available standards to magnitudes which should be faint enough to be accessible for observations with modern detectors on large and very large telescopes.
JHK photometry in the Mauna Kea Observatory (MKO) near-IR system is presented for 115 stars. Of these, 79 are UKIRT standards and 42 are LCO standards. The average brightness is 11.5 mag, with a range of 10 to 15. The average number of nights each star was observed is 4, and the average of the internal error of the final results is 0.011 mag. These JHK data agree with those reported by other groups to 0.02 mag. The measurements are used to derive transformations between the MKO JHK photometric system and the UKIRT, LCO and 2MASS systems. The 2MASS-MKO data scatter by 0.05 mag for redder stars: 2MASS-J includes H2O features in dwarfs and MKO-K includes CO features in giants. Transformations derived for stars whose spectra contain only weak features cannot give accurate transformations for objects with strong absorption features within a filter bandpasses. We find evidence of systematic effects at the 0.02 mag level in the photometry of stars with J<11 and H,K<10.5. This is due to an underestimate of the linearity correction for stars observed with the shortest exposure times; very accurate photometry of stars approaching the saturation limits of infrared detectors which are operated in double-read mode is difficult to obtain. Four stars in the sample, GSPC S705-D, FS 116 (B216-b7), FS 144 (Ser-EC84) and FS 32 (Feige 108), may be variable. 84 stars in the sample have 11< J< 15 and 10.5<H,K<15, are not suspected to be variable, and have magnitudes with an estimated error <0.027 mag; 79 of these have an error of <0.020 mag. These represent the first published high-accuracy JHK stellar photometry in the MKO photometric system; we recommend these objects be employed as primary standards for that system [abridged].
Template fits to observed galaxy fluxes allow calculation of K-corrections and
We construct a filtered simplicial complex $(X_L,f_L)$ associated to a subset $Xsubset mathbb{R}^d$, a function $f:Xrightarrow mathbb{R}$ with compactly supported sublevel sets, and a collection of landmark points $Lsubset mathbb{R}^d$. The persistence values $f_L(Delta)$ are defined as the minimizing values of a family of constrained optimization problems, whose domains are certain higher order Voronoi cells associated to $L$. We prove that $H_k^{a,b}(X_L)cong H^{a,b}_k(X)$ provided that $f$ is the restriction of a smooth function, the landmarks are sufficiently dense, and $a<b$ are generic, and we show that the construction produces desirable results in some examples.
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