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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 U images 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 - Unpolarised standard; high proper motion Carlsberg meridian star (CMC)
Staff obs.
18 August 1999 CMC 609784 H 0.55 - Unpolarised standard; high proper motion Carlsberg meridian star (CMC)
Staff obs.
18 August 1999 CMC 609784 K 0.10 - Unpolarised standard; high proper motion Carlsberg meridian star (CMC)
Staff obs.
1999? HD38563C K 2.10(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) Unpolarised 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 CMC 809557 J(MK) 0.82 - UnPolarised standard; high proper motion Carlsberg meridian star (CMC)
Staff obs.
21 March 2003 CMC 809557 H(MK) 0.83 - UnPolarised standard; high proper motion Carlsberg meridian star (CMC)
Staff obs.
21 March 2003 CMC 809557 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 July 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 IJ1.1um
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 JH1.3um
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 HK1.65um
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 IJ1.1um
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 JH1.3um
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 HK1.65um
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 HK1.65um
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.


Contact: Tom Kerr. Updated: Mon Sep 10 10:37:00 HST 2007

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