Filters
Here you can find the latest filter curves used by the CSP. These have been derived by scans performed by a group from Texas A&M including Jean-Philippe Rheault, Jennifer Marshall, Darren Depoy, and Steven Villanueva. They measured the relative throughput of the telescope and SiTE #3 CCD using a monochromator based light source with a 2.5nm bandwidth FWHM for each of the filters: B, V, u, g, r, i and no filter. They also performed the same measures on the IR camera Retrocam with the J, H and Y filters, which are now complete and shown below. The K-band scan is still a work in progress.
- The latest data release includes a discussion on the zero-points and can be found here.
- The entire filter package can be downloaded from here.
- To include the latest CSP-I and CSP-II filters into SALT2, download this package and follow the instructions.
- To include the latest CSP-I and CSP-II filters into MLCS2k2, download this package and un-tar it in the MLCS aux folder.
Above figures show the relative shapes of the filters. In the case of the optical filters, the current scans (from Stritgzinger et al. (2011)) are compared to the older filter curves from Contreras et al. (2010). In the case of the NIR filters, YJH are the filled colored curves and the old filter functions form Contreras et al. (2010) are drawn as dashed black lines.
The following table lists the zero-points for the optical filters from Krisciunas et al. (2017) . Click on the name to retrieve the filter response function, or get them all at once, including the individual optical components here. Note that there are 3 different V-band filters owing to the fact that the original (V LC-3014) was damaged on Jan. 14 2006. It was replaced with LC-3099 until Jan. 25 2006, when a closer match to the original (LC-9844) was installed and has been used ever since. We also include the CSP-II filters, which will be described more fully in an upcoming publication.
| Name | Date Range | Effective Wavelength (A) | zero-point* | AB offset*** | Reference SED | Standard magnitude | color term** | Natural Magnitude | Instrument |
|---|---|---|---|---|---|---|---|---|---|
| u | 01/01/2003 - 10/2013 | 3639.3 | 12.986 | -0.058 | BD+174708 | 10.56 | 0.046(017) | 10.518 | Swope Site2 CCD |
| g | 01/01/2003 - 10/2013 | 4765.1 | 15.111 | -0.017 | BD+174708 | 9.64 | -0.014(011) | 9.644 | Swope Site2 CCD |
| r | 01/01/2003 - 10/2013 | 6223.3 | 14.902 | -0.006 | BD+174708 | 9.35 | -0.016(015) | 9.352 | Swope Site2 CCD |
| i | 01/01/2003 - 10/2013 | 7609.2 | 14.545 | +0.001 | BD+174708 | 9.25 | -0.002(015) | 9.250 | Swope Site2 CCD |
| B | 01/01/2003 - 10/2013 | 4350.6 | 14.328 | -0.125 | Vega | 0.03 | 0.061(012) | 0.030 | Swope Site2 CCD |
| V-3014 | 01/01/2003 - 01/13/2006 | 5369.6 | 14.437 | -0.016 | Vega | 0.03 | -0.058(011) | 0.0096 | Swope Site2 CCD |
| V-3009 | 01/14/2006 - 01/24/2006 | 5401.4 | 14.393 | -0.019 | Vega | 0.03 | -- | 0.0145 | Swope Site2 CCD |
| V-9844 | 01/25/2006 - 10/2013 | 5375.2 | 14.439 | -0.020 | Vega | 0.03 | -0.058(011) | 0.0096 | Swope Site2 CCD |
| Y | 01/01/2003 - 07/2011 | 10350.8 | 13.921 | +0.629 | Vega | 0 | 0 | 0 | Swope RetroCam |
| J | 01/01/2003 - 01/15/2009 | 12386.5 | 13.836 | +0.912 | Vega | 0 | 0 | 0 | Swope RetroCam |
| J | 01/15/2009 - 07/2011 | 12356.3 | 13.836 | +0.901 | Vega | 0 | 0.016 | 0 | Swope RetroCam |
| H | 01/01/2003 - 07/2011 | 16297.7 | 13.510 | +1.343 | Vega | 0 | -0.029 | 0 | Swope RetroCam |
| Y | 01/01/2003 - 07/2011 | 10439.8 | 13.770 | +0.629 | Vega | 0 | -0.042 | 0 | Dupont WIRC |
| J | 01/01/2003 - 07/2011 | 12383.2 | 13.866 | +0.912 | Vega | 0 | 0.016 | 0 | Dupont WIRC |
| H | 01/01/2003 - 07/2011 | 16282.8 | 13.502 | +1.342 | Vega | 0 | -0.029 | 0 | Dupont WIRC |
| CSPII | |||||||||
| u | 10/2013 - present | 3615.1 | 13.163 | -0.046 | BD+174708 | 10.56 | 0.030(020) | 10.529 | Swope e2v CCD |
| g | 10/2013 - present | 4646.6 | 15.271 | -0.012 | BD+174708 | 9.64 | -0.005(014) | 9.643 | Swope e2v CCD |
| r | 10/2013 - present | 6142.3 | 14.975 | -0.004 | BD+174708 | 9.35 | -0.001(022) | 9.351 | Swope e2v CCD |
| i | 10/2013 - present | 7573.8 | 14.767 | +0.003 | BD+174708 | 9.25 | 0.021(018) | 9.250 | Swope e2v CCD |
| B | 10/2013 - present | 4338.1 | 14.529 | -0.126 | Vega | 0.03 | 0.091(015) | 0.030 | Swope e2v CCD |
| V | 10/2013 - present | 5354.7 | 14.571 | -0.020 | Vega | 0.03 | -0.062(015) | 0.009 | Swope e2v CCD |
| Y | 07/2011 - present | 10353.1 | 13.920 | 0.632 | Vega | 0 | 0 | 0 | DuPont + RetroCam |
| J | 07/2011 - present | 12364.0 | 13.826 | 0.904 | Vega | 0 | 0.019 | 0 | DuPont + RetroCam |
| H | 07/2011 - present | 16214.4 | 13.520 | 1.339 | Vega | 0 | -0.039 | 0 | DuPont + RetroCam |
* The zero points (zp) are in the sense that m = -2.5log(F) + zp, where F is the photon flux through filter SX:
** The color terms are used to convert standard to natural photometry:
*** The AB offsets are in the sense that m(AB) = m(natural) + offset.
Primary Standards
It is important to realize that the CSP BV and YJHK photometry are based on the standards of Landolt (2007) while the ugri photometry is based on the standards of Smith et al. (2002). In both cases, the standard magnitudes tabulated in those references are converted to our natural system magnitudes using the color terms published in Krisciunas et al. (2017) and Phillips et al. (2019). These natural system magnitudes are available here.
