Polarimetry Standards Observed at UKIRT
Polarised and Unpolarised Standards Observed at UKIRT
Although polarised and unpolarised standards are occasionally observed by UKIRT staff, it is important that such targets are also observed by visiting observers, in the same observing mode that is to be used on their science targets. However, since the results of these observations may be of interest to other users, we list below data kindly provided by visiting observers.
If you have observed a polarised or unpolarised standard at UKIRT… please consider sharing your results with the community! Please send details of the target, values for percentage polarisation and angle, plus details of the observations (instrument, filter, date of observations, etc.) to Chris Davis at the JAC. Thanks!
A Note about Unpolarised Standards: Since unpol. standards by necessity are usually close to the earth, they are often very bright. Some of the “high” values for instrumental polarisation given below may therefore be due to on-source counts being in the non-linear regime (> 5000 counts with UFTI and UIST). Observers should be wary of over-exposing on standards. It may even be necessary to defocus the telescope slightly.
A very basic cshell script is available for calculating the percent polarisation and angle from the I, Q and Uimages produced by the pipeline; simply enter the integrated counts (from Gaia – aperture photometry): calc-pol.prg
Imaging Polarimetry with UFTI
On polarised standards, UFTI imaging polarimetry usually gives angles that are GREATER than catalogued values by about 9 degrees. The orac-DR automatically applies this correction to imaging-polarimetry observations (see output from orac-DR for details).
| Date | Target | Filter | % Pol | PA (degs) | Notes |
| 18 August 1999 | CMC 511213 | I | 0.58 | – | Unpolarised standard; high proper motion Carlsberg meridian star (CMC) Staff obs. |
| 18 August 1999 | CMC 511213 | J | 0.22 | – | Unpolarized standard; high proper motion Carlsberg meridian star (CMC) Staff obs. |
| 18 August 1999 | CMC 609784 | H | 0.55 | – | Unpolarized standard; high proper motion Carlsberg meridian star (CMC) Staff obs. |
| 18 August 1999 | CMC 609784 | K | 0.10 | – | Unpolarized standard high proper motion Carlsberg meridian star (CMC) Staff obs. |
| 1999? | HD38563C | K | 1.20(0.1) | 87(6) | Polarised standard: K=2.21%,PA=78deg (Whittet et al., 1992, ApJ, 386, 562) Staff obs. |
| 16 Jan 2001 | CMC604707 | J | 0.25(0.05) | 168(5) | Unpolarized standard observed with telescope defocused, used 3.6″ aperture: details in Kishimoto, Antonucci & Blaes, 2005, MNRAS. (astroph/0509341) |
| 16 Jan 2001 | CMC604707 | H | 0.09(0.03) | 105(9) | Unpolarised standard observed with telescope defocused, used 3.6″ aperture: details in Kishimoto, Antonucci & Blaes, 2005, MNRAS. (astroph/0509341) |
| 16 Jan 2001 | CMC604707 | K’ | 0.12(0.04) | 124(10) | Unpolarised standard observed with telescope defocused, used 3.6″ aperture: details in Kishimoto, Antonucci & Blaes, 2005, MNRAS. (astroph/0509341) |
| 15 Jan 2001 | CMC604919 | J | 0.14(0.02) | 92(5) | Unpolarised standard observed with telescope defocused, used 7.5″ aperture: details in Kishimoto, Antonucci & Blaes, 2005, MNRAS. (astroph/0509341) |
| 15 Jan 2001 | CMC604919 | H | 0.19(0.01) | 100(2) | Unpolarised standard observed with telescope defocused, used 7.5″ aperture: details in Kishimoto, Antonucci & Blaes, 2005, MNRAS. (astroph/0509341) |
| 15 Jan 2001 | CMC604919 | K’ | 0.14(0.02) | 82(4) | Unpolarised standard observed with telescope defocused, used 7.5″ aperture: details in Kishimoto, Antonucci & Blaes, 2005, MNRAS. (astroph/0509341) |
| 8 July 2005 | SAO82926 | J | 0.09(0.06) | 157(21) | Unpolarised standard observed with telescope defocused, used 2.7″ aperture: details in Kishimoto, Antonucci & Blaes, 2005, MNRAS. (astroph/0509341) |
| 8 July 2005 | SAO82926 | K’ | 0.11(0.04) | 29(12) | Unpolarised standard observed with telescope defocused, used 2.7″ aperture: details in Kishimoto, Antonucci & Blaes, 2005, MNRAS. (astroph/0509341) |
| 8 July 2005 | SAO82926 | J | 0.24(0.05) | 99(6) | Unpolarised standard observed with telescope defocused, used 3.6″ aperture: details in Kishimoto, Antonucci & Blaes, 2005, MNRAS. (astroph/0509341) |
| 8 July 2005 | SAO82926 | K’ | 0.24(0.05) | 59(6) | Unpolarised standard observed with telescope defocused, used 3.6″ aperture: details in Kishimoto, Antonucci & Blaes, 2005, MNRAS. (astroph/0509341) |
| 12 August 2005 | Cyg OB2 no.15 | K | 0.40 | 92 | Polarised standard: K=0.74%,PA=85deg (Whittet et al., 1992, ApJ, 386, 562) U/05A/42 – reduced by pipeline. |
- Errors given in brackets.
- UFTI has been on the same telescope (west) port since it was installed.
Imaging Polarimetry with UIST
On polarised standards, UIST imaging polarimetry usually gives angles that are GREATER than catalogued values by about 24 degrees. The ORAC-DR pipeline automatically applies this correction to imaging-polarimetry observations.
| Date | Target | Filter | % Pol | PA (degs) | Notes |
| 21 March 2003 | CMC809557 | J(MK) | 0.82 | – | UnPolarised standard; high proper motion Carlsberg meridian star (CMC) Staff obs. |
| 21 March 2003 | CMC809557 | H(MK) | 0.83 | – | UnPolarised standard; high proper motion Carlsberg meridian star (CMC) Staff obs. |
| 21 March 2003 | CMC809557 | K(MK) | 0.27 | – | UnPolarised standard; high proper motion Carlsberg meridian star (CMC) Staff obs. |
| 26 July 2005 | Cyg OB2 no.3 | J(MK) | 4.3 | 116 | Polarised standard; J=2.8%,PA=105deg (Whittet et al., 1992, ApJ, 386, 562) PATT run; data reduced with orac-DR pipeline |
| 21 March 2005 | Cyg OB2 no.3 | K(MK) | 1.5 | 128 | Polarised standard; K=1.2%,PA=108deg (Whittet et al., 1992, ApJ, 386, 562) PATT run; data reduced with orac-DR pipeline |
| 18 June 2007 | Ross 128 | H(MK) | 0.22(0.11) | 121 | UnPolarised standard. 07A PATT run; data reduced by PI (Wisniewski et al.) with IRAF |
| 17 June 2007 | GD319 | H(MK)) | 0.43(0.89) | 160 | UnPolarised standard. 07A PATT run; data reduced by PI (Wisniewski et al.) with IRAF |
| 17 June 2007 | GD319 | H(MK) | 0.30(0.95) | 22 | UnPolarised standard. 07A PATT run; data reduced by PI (Wisniewski et al.) with IRAF |
| 18 June 2007 | GD319 | H(MK) | 0.75(1.10) | 111 | UnPolarised standard. 07A PATT run; data reduced by PI (Wisniewski et al.) with IRAF |
| 16 June 2007 | HD147343 | H(MK) | 0.35(0.26) | 115 | Polarised standard; H=0.45%,PA=87deg (Whittet et al., 1992, ApJ, 386, 562) 07A PATT run; data reduced by PI (Wisniewski et al.) with IRAF |
| 18 June 2007 | HD147343 | H(MK) | 0.44(0.26) | 99 | Polarised standard; H=0.45%,PA=87deg (Whittet et al., 1992, ApJ, 386, 562) 07A PATT run; data reduced by PI (Wisniewski et al.) with IRAF |
| 17 June 2007 | Cyg OB2 no.3 | H(MK) | 1.85(0.12) | 98 | Polarised standard; H=1.81%,PA=105deg (Whittet et al., 1992, ApJ, 386, 562) 07A PATT run; data reduced by PI (Wisniewski et al.) with IRAF |
| 23 July 2007 | Cyg OB2 no.3 | H(MK) | 1.10(0.11) | 104 | Polarised standard; H=1.81%,PA=105deg (Whittet et al., 1992, ApJ, 386, 562) 07A PATT run; data reduced by PI (Wisniewski et al.) with IRAF |
- Errors given in brackets.
- UIST has been on the same (south) telescope port since it was installed in 2002.
Spectro-Polarimetry with UIST
Observations of polarised standards usually give percentage polarisation consistent with catalogue values. However, position angles are often quite random, and dependent on the package used to reduce the same dataset! Input from users who have observed polarised standards would be greatly appreciated! At the present time, NO correction is applied to the PA by the pipeline DR.
| Date | Target | Grism | Wavelength | % Pol | PA (degs) | Notes |
| March 2003 | Rho Oph Elias 14 | HK | 1.5 to 2.3um | 2.8 – 1.6 | 19-25 | Polarised standard: H=3.2%,PA=3deg; K=2.0%,PA=3deg (Whittet et al., 1992, ApJ, 386, 562) Staff obs./ reduced offline with TSP |
| March 2003 | HD 125184 | HK | 1.5 to 2.3um | 0.3(0.1) | – | Unpolarised standard, from “Planets, Stars & Nebulae studied with Photopolarimetry”, 1974, ed. T. Gehrels, Univ. Arizona Press, pp. 168. Staff obs./ reduced offline with TSP |
| March 2003 | HD 125184 | Short-K | ~2.2um | 0.35(0.07) | – | Unpolarised standard, from “Planets, Stars & Nebulae studied with Photopolarimetry”, 1974, ed. T. Gehrels, Univ. Arizona Press, pp. 168. Staff obs./ reduced offline with TSP |
| March 2003 | HD 125184 | Long-L | ~4.0um | 0.5(0.2) | – | Unpolarised standard, from “Planets, Stars & Nebulae studied with Photopolarimetry”, 1974, ed. T. Gehrels, Univ. Arizona Press, pp. 168. Staff obs./ reduced offline with TSP |
| 18 July 2004 | HD 105193 | HK | 1.6um 2.2um | 2.3 1.7 | -9 -10 | Polarised standard: H=2.3%,PA=60deg; K=1.7%,PA=60deg (Whittet et al., 1992, ApJ, 386, 562) Staff obs./ reduced offline with polpack (pipeline gives same results) |
| 18 Julu 2004 | HD 183143 | HK | 1.6um 2.2um | 1.3 0.7 | -70 -80 | Polarised standard: H=1.7%,PA=0deg; K=0.7%,PA=0deg (Planets, Stars & Nebulae studied with Photopolarimetry”, 1974, T. Gehrels (ed.), University of Arizona Press, Tuscon) Staff obs./ reduced offline with polpack (pipeline gives same results) |
| 18 July 2004 | HD 144287 | HK | 1.6um 2.2um | 0.06 0.08 | – | Unpolarised standard, from “Planets, Stars & Nebulae studied with Photopolarimetry”, 1974, ed. T. Gehrels, Univ. Arizona Press, pp. 168. Staff obs./ reduced offline with polpack (pipeline gives same results) |
| 8 July 2005 | HD 150193 | IJ | 1.1um 1.3um | 6.6(1.0) 2.8(0.1) | 12(2)* 29(2)* | Polarised standard: I=5.0%,PA=57deg; J=3.3%,PA=57deg (Whittet et al., 1992, ApJ, 386, 562) Staff obs./ reduced with pipeline; Values are mean over 100 pixels (~0.06um) |
| 8 July 2005 | HD 150193 | JH | 1.3um 1.65um | 2.9(0.1) 2.1(0.1) | 27(1)* 28(1)* | Polarised standard: J=3.3%,PA=57deg; H=2.3%,PA=60deg (Whittet et al., 1992, ApJ, 386, 562) Staff obs./ reduced with pipeline; Values are mean over 100 pixels (~0.08um) |
| 8 July 2005 | HD 150193 | HK | 1.65um 2.2um | 2.2(0.1) 1.7(0.1) | 28(1)* 29(1)* | Polarised standard: H=2.3%,PA=60deg; K=1.7%,PA=60deg (Whittet et al., 1992, ApJ, 386, 562) Staff obs./ reduced with pipeline; Values are mean over 100 pixels (~0.11um) |
| 8 July 2005 | HD 144287 | IJ | 1.1um 1.3um | 0.93(0.2) 0.41(0.1) | – | Unpolarised standard, from “Planets, Stars & Nebulae studied with Photopolarimetry”, 1974, ed. T. Gehrels, Univ. Arizona Press, pp. 168. Staff obs./ reduced with pipeline; Values are mean over 100 pixels (~0.06um) |
| 8 July 2005 | HD 144287 | JH | 1.3um 1.65um | 0.25(0.1) 0.19(0.1) | – | Unpolarised standard, from “Planets, Stars & Nebulae studied with Photopolarimetry”, 1974, ed. T. Gehrels, Univ. Arizona Press, pp. 168. Staff obs./ reduced with pipeline; Values are mean over 100 pixels (~0.08um) |
| 8 July 2005 | HD 144287 | HK | 1.65um 2.2um | 0.26(0.09) 0.41(0.12) | – | Unpolarised standard, from “Planets, Stars & Nebulae studied with Photopolarimetry”, 1974, ed. T. Gehrels, Univ. Arizona Press, pp. 168. Staff obs./ reduced with pipeline; Values are mean over 100 pixels (~0.11um) |
| 22 July 2005 | CyG OB2 No.3 | HK | 1.65um 2.2um | 1.7 1.0 | 138 135 | Polarised standard: H=1.8%,PA=105deg; K=1.2%,PA=108deg (“Planets, Stars & Nebulae studied with Photopolarimetry”, 1974, T. Gehrels (ed.), University of Arizona Press, Tuscon, p. 170) Reduced with pipeline; Values are approximate |
- Click on Grism name to see data, where available.
- Errors given in brackets.
- UIST has been on the same (south) telescope port since it was installed in 2002.
Spectro-Polarimetry with CGS4
Note that, because the prism in CGS4 comes before the slit in the optical train, we encourage users to use UIST for all spectro-polarimetry.
| Date | Target | Wavelength | % Pol. | PA (degs) | Notes |
| 26 Sep 1999 | HD 10476/202573 | 1.2um | 0.17 | 122.5 | UnPolarised standards, data from two sources combined. Details in Oudmaijer et al. (2005), MNRAS |
| 26 Sep 1999 | HD 23512 | 1.2um | 1.34 | 29.5 | Polarised standard; predicted pol is J=1.19%,PA= 30deg (extrapolating Serkowski from the R-band values of Hsu & Breger 1982, ApJ, 262, 732); Oudmaijer et al. (2005), MNRAS |
| 26 Sep 1999 | HD 43384 | 1.2um | 1.50 | 171.7 | Polarised standard; predicted pol is J=1.23%,PA= 171deg (extrapolating Serkowski from the R-band values of Hsu & Breger 1982, ApJ, 262, 732); Oudmaijer et al. (2005), MNRAS |
| 26 Sep 1999 | HD 7927 | 1.2um | 1.40 | 96.5 | Polarised standard; predicted pol is J=1.29% (extrapolating Serkowski from the R-band values of Hsu & Breger 1982, ApJ, 262, 732); Oudmaijer – private communication. |