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MOIRCS FiltersBroadband FiltersThe following table lists the broad-band filters currently installed in MOIRCS, together with their estimated sensitivities. Our broad band filters are designed to follow the MKO filter system (Tokunaga, Simons, and Vacca 2002, PASP, 114, 180; Warren & Hewett 2002, ASP Conf, Vol 283, 369). The transmission curves of each filter are from the data sheets from suppliers. Estimated sensitivities listed are for a 5 sigma detection in 1 hour of integration, assuming good (0.5'') seeing and a moderately sky condition (=same sky background flux as the Subaru ETC: see also the Exposures page). Point source S/N is measured in a 1.5''-diameter aperture where we assume all the light from the source is in it. Extended source sensitivities are in mag per arcsec2. All the magnitudes are in AB unit. Broad-Band Filters(*1) For the conversion from Vega to AB magnitude we use Y_AB=Y_vega+0.64, J_AB=J_vega+0.94, H_AB=H_vega+1.38, Ks_AB=Ks_vega+1.86 (Tokunaga & Vacca 2005)
Notes:Medium-Band FiltersTwo new medium-band filters in K-band window are newly available from S23A(Note 1). The central wavelength (CW) and band width (BW: defined by FWHM) of filters listed below are from the company-provided datasheets. The peak transmittance is almost 100 % (!) for both filters. [Updated 2/18/23] The estimated sensitivities listed are for a 5 sigma detection in 1-hour integration, assuming a good seeing & dark sky condition(Note 2). The S/N is measured in a 1.5''-diameter aperture where we assume all the light from the source is in it. Extended source sensitivities are in mag per arcsec2. These values are in AB magnitude system. Medium-Band Filters
(1) They were made by the team led by Dr. Yusei Koyama (NAOJ) in 2021 with the financial aid of Subaru GLAO A-Project (ULTIMATE-Subaru Project) and opened to public use. Please read the policy for use. (2) These values are based on the data taken in Feb-May 2023. The actual background level largely depends on the atmospheric condition, especially for K4. We observed +-30% (for K3) to 50% (for K4) variation from day to day basis. (3) These values are for the channel 1. The actual 1 hr exposure data could be shallower due to some additional noise source such as the bias drift, variable sky fluctuation, the additional noise by the sky subtraction process. Narrow-Band FiltersThe central wavelength (CW) and band width (BW: defined by FWHM) of filters listed below are mostly from the direct measurement as installed in MOIRCS. The measurement values show very good agreement with the company-provided datasheets. Peak transmittance are around 80 to 90%, except for H2 and Kcont filters. Narrow-Band Filters
(1) They are originally the user (carry-in) filters. Please read the policy for use. (2) The data are not from the direct measurement but from the datasheet by supplied companies. (3) The transimission curve presented here is the data directly measured from the dome flat. (4) The background level of NB119 filter is very dark. Minimum exposure of ~30 minutes is sometimes required to reach the background-noise-limited case. Sky subtraction is generally difficult due to the change of the background.
Sky Counts by Each NB Filter
The Shift of Transmission Curve within the FOV K-Continuum and ND FiltersThe K-Continuum filter and the ND filters were decomissioned in 2022. As for Kcont filter, we instead introduced the K3 medium-band filter (MBK3). Please use the filter instead. User FiltersWe welcome the user filters. The detail and the user filter policy can be found in the User Filter Policy page. Please first contact to the primary SA if you are planning to make a carry-in filters, because the vacant slots are quite limited now. The Old MOIRCS Filter PageThe old "MOIRCS Filter" page (for old detectors till May 2015) can be found here .Please note that all data on these pages are subject to change as the evaluation of the performance of MOIRCS progresses. Updated 2023-05-12 |