faint standards

UKIRT Faint Standards tramsformed to the (new) Mauna Kea Observatory (MKO-NIR) system

Both UKIRT cameras (UFTI and IRCAM) are now equipped with filters from the Mauna Kea Consortium (MKO-NIR) filter set (see this filter specification page) or the papers "The Mauna Kea Observatories Near-Infrared Filter Set. I. Defining Optimal 1-5 Micron Bandpasses" by Simons & Tokunaga 2002 PASP 114, 169 and "The Mauna Kea Observatories Near-Infrared Filter Set. II. Specifications for a New JHKL'M' Filter Set for Infrared Astronomy" by Tokunaga et al. 2002 PASP, 114, 180. These filters have been designed to be a better match to the atmospheric windows, offering maximum sensitivity together with minimum dependance on altitude and atmospheric water-vapour content, and are also of excellent optical quality.

The MKO-NIR filter set has been in UFTI since commissioning in October 1998, and replaced the old JHK set in IRCAM/TUFTI prior to commissioning of its new plate scale in September 1999. Both the J and H filters are significantly different from the old filters and hence the magnitudes for the Faint Standards on the old IRCAM3 system are no longer on the natural systems of the imagers. Colour transformations have been derived in two ways: one empirically based on UFTI photometry and the other calculated by convolving the known filter profiles with spectroscopic data for a representative set of red stars. The two determinations agree well. Note that the transformations for IRCAM/TUFTI with the same filter set should be effectively identical.

The transformations between the old IRCAM3 system and the new MKO-NIR system at H and K are well behaved and single-valued. However for the J filter different terms have to be applied depending whether or not the standard star has intrinsic water absorption features. This is due to the fact that the new J filter cuts off shorter than the old filter, specifically to avoid water absorption in the terrestrial atmosphere. We have determined that for stars with no intrinsic water features the colour transformations are:

K(old) = K(new) + 0.020[+/-0.005](J-K)(new)
(J-H)(old) = 1.040[+/-0.010](J-H)(new)
(H-K)(old) = 0.830[+/-0.010](H-K)(new)
(J-K)(old) = 0.960[+/-0.010](J-K)(new)


K(new) = K(old) - 0.020[+/-0.005](J-K)(old)
(J-H)(new) = 0.960[+/-0.010](J-H)(old)
(H-K)(new) = 1.205[+/-0.010](H-K)(old)
(J-K)(new) = 1.040[+/-0.010](J-K)(old)
however for stars with significant water absorption, stars with spectral type M4 through to the L class (but not including the T class with methane absorption):
K(new) = K(old) - 0.020[+/-0.005](J-K)(old)
(J-H)(new) = 0.870[+/-0.010](J-H)(old)
(H-K)(new) = 1.205[+/-0.010](H-K)(old)
(J-K)(new) = 0.980[+/-0.010](J-K)(old)
We have applied the appropriate transformations to the UKIRT Faint Standards and the Table below lists the combined fundamental and extended standards list with the photometry given in the cameras' current natural system, which is defined by the Mauna Kea consortium JHK filters. The errors include both observational error and system transformation uncertainty. Note however that we are currently in the process of reobserving these standards directly through the MK set and in some cases find differences between the transformed and observed values. The direct observations should be more accurate and the preliminary values are available at Summary Text File of IZJHKL'M' Magnitudes. The number of observations and errors given in this text file are not accurate but the magnitudes are the best currently available.

For more information on e.g. selection of standard stars see the following sections on either the original Fundamental List of UKIRT standards or the later Extended List.



Number  Other         RA  (J2000)  Dec         K     sem    N      J-H    sem    N       H-K    sem    N   Invis
        Name                                                                                               on TV?
FS   1  G158-100  00 33 54.48 -12 07 58.1   12.955 (0.005) [09]    0.372 (0.005) [10]    0.069 (0.004) [09]
FS   2  SA92-342  00 55 09.93 +00 43 13.1   10.467 (0.004) [12]    0.198 (0.004) [11]    0.042 (0.002) [12]
FS   3  F11       01 04 21.63 +04 13 36.0   12.827 (0.003) [07]   -0.107 (0.003) [07]   -0.107 (0.005) [08]
FS   4  SA93-317  01 54 37.70 +00 43 00.5   10.279 (0.002) [11]    0.229 (0.005) [11]    0.039 (0.002) [11]
FS   5  F16       01 54 34.65 -06 46 00.4   12.339 (0.005) [08]    0.004 (0.002) [07]   -0.006 (0.002) [08]
FS   6  F22       02 30 16.64 +05 15 51.1   13.385 (0.005) [08]   -0.057 (0.005) [08]   -0.083 (0.005) [08]
FS   7  SA94-242  02 57 21.21 +00 18 38.2   10.942 (0.002) [14]    0.121 (0.002) [14]    0.039 (0.001) [14]
FS  10  GD50      03 48 50.20 -00 58 31.2   14.987 (0.011) [09]   -0.100 (0.006) [09]   -0.142 (0.010) [09]
FS  11  SA96-83   04 52 58.92 -00 14 41.6   11.252 (0.002) [18]    0.062 (0.001) [18]    0.027 (0.001) [18]
FS  12  GD71      05 52 27.66 +15 53 14.3   13.920 (0.006) [13]   -0.110 (0.003) [13]   -0.113 (0.005) [13]
FS  13  SA97-249  05 57 07.59 +00 01 11.4   10.133 (0.003) [12]    0.300 (0.004) [13]    0.058 (0.001) [12]
FS  14  Rubin149  07 24 14.40 -00 33 04.1   14.200 (0.008) [08]   -0.062 (0.007) [08]   -0.037 (0.010) [08]
FS  15  M67-I-48  08 51 05.81 +11 43 46.9   12.340 (0.004) [13]    0.324 (0.005) [13]    0.065 (0.002) [13]
FS  16  M67-IV-8  08 51 15.01 +11 49 21.2   12.621 (0.004) [11]    0.278 (0.004) [11]    0.049 (0.002) [11]
FS  17  M67-IV-27 08 51 19.31 +11 52 10.4   12.266 (0.003) [10]    0.314 (0.004) [10]    0.067 (0.002) [10]
FS  18  SA100-280 08 53 35.51 -00 36 41.7   10.521 (0.002) [11]    0.242 (0.004) [11]    0.049 (0.002) [11]
FS  19  G162-66   10 33 42.75 -11 41 38.3   13.786 (0.006) [09]   -0.082 (0.005) [09]   -0.139 (0.007) [09]
FS  20  G163-50   11 07 59.93 -05 09 26.1   13.503 (0.010) [06]   -0.036 (0.006) [06]   -0.078 (0.008) [06]
FS  21  GD140     11 37 05.15 +29 47 58.4   13.150 (0.002) [09]   -0.066 (0.004) [09]   -0.108 (0.004) [09]
FS  33  GD153     12 57 02.30 +22 01 52.8   14.258 (0.005) [06]   -0.108 (0.002) [05]   -0.124 (0.008) [05]
FS  23  M3-193    13 41 43.57 +28 29 49.5   12.363 (0.004) [11]    0.506 (0.006) [11]    0.080 (0.003) [11]
FS  27  M13-A14   16 40 41.56 +36 21 12.4   13.121 (0.005) [10]    0.294 (0.006) [10]    0.058 (0.004) [10]
FS  35  anon      18 27 13.52 +04 03 09.4   11.739 (0.005) [14]    0.354 (0.005) [15]    0.101 (0.002) [15]
FS  34  EG141     20 42 34.73 -20 04 34.8   13.003 (0.004) [09]   -0.074 (0.003) [09]   -0.089 (0.005) [09]
FS  29  G93-48    21 52 25.36 +02 23 20.7   13.314 (0.003) [11]   -0.065 (0.002) [11]   -0.084 (0.003) [11]
FS  30  SA114-750 22 41 44.72 +01 12 36.5   12.023 (0.003) [15]   -0.040 (0.002) [13]   -0.037 (0.002) [14]
FS  31  GD246     23 12 21.60 +10 47 04.1   14.042 (0.007) [10]   -0.125 (0.005) [10]   -0.119 (0.005) [10]
FS  32  F108      23 16 12.37 -01 50 34.6   13.680 (0.007) [08]   -0.103 (0.003) [08]   -0.104 (0.005) [08]
FS 101  fs2-29    00 13 43.58 +30 37 59.9   10.381 (0.006) [08]    0.133 (0.004) [08]    0.039 (0.003) [08]
FS 102  p525-e    00 24 28.50 +07 49 00.1   11.211 (0.005) [06]    0.305 (0.006) [07]    0.063 (0.002) [06]
FS 103  p241-g    00 36 29.60 +37 42 54.3   11.719 (0.007) [06]    0.494 (0.006) [06]    0.101 (0.006) [06]
FS 104  p194-r    01 04 59.43 +41 06 30.8   10.406 (0.005) [07]    0.097 (0.004) [07]    0.031 (0.002) [07]
FS 105  p527-f    01 19 08.19 +07 34 11.5   10.959 (0.005) [06]    0.452 (0.009) [06]    0.096 (0.001) [06]
FS 106  p152-f    01 49 46.94 +48 37 53.2   11.745 (0.006) [05]    0.591 (0.008) [06]    0.124 (0.006) [05]
FS 107  fs2-03    01 54 10.14 +45 50 38.0   10.226 (0.015) [03]    0.204 (0.010) [03]    0.060 (0.004) [03]
FS 108  fs2-04    03 01 09.85 +46 58 47.7    9.724 (0.004) [05]    0.278 (0.005) [05]    0.071 (0.003) [06]
FS 109  g-129     03 13 24.16 +18 49 38.4   10.795 (0.007) [06]    0.445 (0.007) [07]    0.194 (0.004) [07]
FS 110  p533-d    03 41 02.22 +06 56 15.9   11.316 (0.004) [06]    0.296 (0.004) [07]    0.094 (0.004) [07]
FS 111  fs2-05    03 41 08.55 +33 09 35.5   10.282 (0.006) [07]    0.252 (0.007) [07]    0.107 (0.002) [07]
FS 112  s618-d    03 47 40.70 -15 13 14.4   10.893 (0.005) [06]    0.253 (0.005) [06]    0.057 (0.005) [06]
FS 113  p117-f    04 00 14.07 +53 10 38.5   12.422 (0.006) [06]    0.357 (0.005) [06]    0.131 (0.005) [06]
FS 114  Hy214     04 19 41.72 +16 45 22.4   13.426 (0.008) [05]    0.525 (0.006) [06]    0.406 (0.007) [05]
FS 115  b216-b5   04 23 18.17 +26 41 16.4   10.124 (0.012) [06]    1.522 (0.018) [07]    0.930 (0.009) [07] *
FS 116  b216-b7   04 23 50.18 +26 40 07.7   10.914 (0.009) [07]    1.211 (0.014) [06]    0.616 (0.006) [07] *
FS 117  b216-b9   04 23 56.61 +26 36 38.0   10.050 (0.008) [07]    0.912 (0.012) [07]    0.527 (0.005) [07]
FS 118  b216-b13  04 24 33.49 +26 33 37.8   10.426 (0.007) [06]    0.694 (0.009) [06]    0.321 (0.003) [06]
FS 119  fs2-53    05 02 57.44 -01 46 42.6    9.850 (0.004) [06]    0.043 (0.006) [06]    0.023 (0.002) [06]
FS 120  lhs216    06 14 01.44 +15 09 58.3   10.612 (0.007) [06]    0.483 (0.006) [07]    0.240 (0.006) [07]
FS 121  s772-g    06 59 46.82 -04 54 33.2   11.302 (0.004) [07]    0.539 (0.006) [07]    0.130 (0.003) [07]
FS 122  p161-d    07 00 52.02 +48 29 24.0   11.332 (0.003) [07]    0.257 (0.004) [06]    0.055 (0.003) [07]
FS 123  p486-r    08 51 11.88 +11 45 21.5   10.212 (0.004) [10]   -0.012 (0.002) [10]   -0.027 (0.004) [10]
FS 124  lhs254    08 54 12.07 -08 04 58.9   10.761 (0.005) [06]    0.418 (0.008) [07]    0.321 (0.006) [07]
FS 125  p259-c    09 03 20.60 +34 21 03.9   10.365 (0.005) [10]    0.361 (0.004) [09]    0.063 (0.003) [10]
FS 126  p487-f    09 19 18.73 +10 55 54.2   11.667 (0.006) [10]    0.541 (0.006) [10]    0.127 (0.003) [09]
FS 127  p212-c    10 06 29.03 +41 01 26.6   11.648 (0.004) [10]    0.251 (0.005) [09]    0.048 (0.003) [10]
FS 128  lhs2347   11 05 10.40 +07 06 48.7   12.059 (0.006) [05]    0.536 (0.007) [05]    0.372 (0.006) [06]
FS 129  lhs2397a  11 21 48.95 -13 13 07.9   10.686 (0.008) [08]    0.630 (0.009) [08]    0.512 (0.005) [07]
FS 130  p264-f    11 24 55.92 +34 44 38.5   12.238 (0.005) [06]    0.572 (0.008) [07]    0.119 (0.004) [06]
FS 131  p266-c    12 14 25.40 +35 35 55.6   11.308 (0.005) [05]    0.249 (0.004) [06]    0.039 (0.004) [05]
FS 132  s860-d    12 21 39.36 -00 07 13.3   11.830 (0.004) [06]    0.278 (0.004) [07]    0.041 (0.005) [06]
FS 133  p172-e    13 15 52.80 +46 06 36.9   11.868 (0.005) [05]    0.352 (0.006) [05]    0.072 (0.003) [04]
FS 134  lhs2924   14 28 43.37 +33 10 41.5   10.724 (0.007) [06]    0.649 (0.008) [06]    0.511 (0.005) [06]
FS 135  s867-v    14 40 58.04 -00 27 46.6   11.586 (0.004) [05]    0.330 (0.005) [05]    0.055 (0.002) [06]
FS 136  S868-G    14 59 32.05 -00 06 17.0   11.870 (0.006) [06]    0.531 (0.007) [06]    0.108 (0.004) [06]
FS 137  p565-c    16 26 42.72 +05 52 20.3   11.823 (0.006) [05]    0.262 (0.007) [07]    0.054 (0.003) [06]
FS 138  p275-a    16 28 06.72 +34 58 48.3   10.411 (0.006) [07]    0.029 (0.006) [06]    0.002 (0.002) [07]
FS 139  p137-f    16 33 52.96 +54 28 22.1   12.091 (0.007) [07]    0.492 (0.008) [07]    0.110 (0.003) [07]
FS 140  s587-t    17 13 22.65 -18 53 33.8   10.360 (0.006) [05]    0.354 (0.005) [05]    0.072 (0.005) [05]
FS 141  p389-d    17 48 58.87 +23 17 43.7   10.805 (0.006) [07]    0.291 (0.005) [07]    0.074 (0.003) [07]
FS 142  Ser-EC51  18 29 51.26 +01 13 19.0   13.348 (0.016) [02]    1.435 (0.016) [02]    0.904 (0.010) [02] *
FS 143  Ser-EC68  18 29 53.79 +01 13 29.9   12.947 (0.020) [04]    2.243 (0.026) [03]    1.446 (0.013) [04] *
FS 144  Ser-EC84  18 29 56.90 +01 12 47.1   10.970 (0.019) [02]    2.412 (0.030) [02]    1.569 (0.016) [02] *
FS 145  Ser-EC160 18 30 05.81 +01 13 47.3   12.064 (0.025) [04]    3.105 (0.059) [04]    1.882 (0.018) [04] *
FS 146  p280-u    18 54 04.01 +37 07 18.6   10.129 (0.006) [05]    0.491 (0.007) [05]    0.084 (0.003) [05]
FS 147  p230-a    19 01 55.27 +42 29 19.6    9.865 (0.004) [04]    0.027 (0.004) [05]    0.018 (0.003) [05]
FS 148  s810-b    19 41 23.41 -03 50 56.9    9.477 (0.004) [05]    0.019 (0.008) [05]    0.013 (0.005) [05]
FS 149  p338-c    20 00 39.25 +29 58 40.0   10.086 (0.009) [06]    0.022 (0.008) [06]   -0.004 (0.003) [06]
FS 150  fs2-22    20 36 08.44 +49 38 23.5    9.956 (0.005) [08]    0.148 (0.007) [09]    0.053 (0.003) [09]
FS 151  p340-h    21 04 14.75 +30 30 21.2   11.869 (0.007) [08]    0.263 (0.007) [08]    0.074 (0.005) [08]
FS 152  p460-e    22 27 16.12 +19 16 59.2   11.045 (0.006) [09]    0.500 (0.007) [08]    0.075 (0.004) [09]
FS 153  s820-e    23 02 32.07 -03 58 53.1   10.882 (0.005) [06]    0.557 (0.008) [07]    0.127 (0.002) [07]
FS 154  s893-d    23 18 10.08 +00 32 55.6   11.058 (0.005) [06]    0.253 (0.004) [07]    0.051 (0.003) [07]
FS 155  fs2-27    23 49 47.82 +34 13 05.1    9.401 (0.007) [06]    0.491 (0.006) [05]    0.102 (0.003) [06]


NB: (1) FS18 is a double; separation = 1."36, p.a. 96 degrees, Delta(K) = 2.2
    (2) Stars which are too faint in the visible to be readily seen on an acquisition TV are marked with
        an asterisk (*) in the last column.