CDROM/AJ/V105/P0258 Polarization in the Carina Nebula (Marraco+ 1993) ================================================================================ Intracluster Dust Polarization in the Carina Nebula H. G. Marraco, E. I. Vega, F. J. Vrba <1993, AJ, 105, 258> =1993AJ....105..258M ================================================================================ Abstract: We have obtained new UBVRI polarimetric observations of 25 stars and BV polarimetric observations of 60 stars which are embedded in the Carina Nebula. Using these data and photometric data from the literature we have modeled and subtracted the foreground dust contribution in the color excess E(B-V) and the visual polarization. The resulting intracluster dust component is found to have a polarization efficiency less than the maximum observed for the interstellar medium. The intracluster dust is also characterized by a ratio of E(V-K)/E(B-V) to Lambda(max) higher than the canonical value for the interstellar medium. This result is consistent with the anomalous extinction for this region, reported by Tapia et al. [MNRAS, 232, 661 (1988a)], which increases above normal values color excess ratios that are normalized at wavelengths shorter than the V band. File Summary: -------------------------------------------------------------------------------- File Name Lrecl Records Explanations -------------------------------------------------------------------------------- table1.dat 62 61 BV polarimetric observations table2.dat 47 147 UBVRI polarimetric observations table4.dat 92 54 Observed, foreground, and intracluster color excesses and visual polarizations table5.dat 47 105 UBVRI intracluster polarization table6.dat 86 18 UBVRI polarization results table125.tex 111 644 TeX version of tables 1, 2, and 5 table46.tex 141 282 TeX version of landscape tables 4 and 6 -------------------------------------------------------------------------------- Comments for file: table1.dat -------------------------------------------------------------------------------- Table 1 presents data for 60 high luminosity stars (plus Eta Carina) that were observed polarimetrically in the Johnson B and V bandpasses in the years 1978 to 1980. The observations were obtained with the rotating analyzer polarimeter at La Plata Observatory using the 83 cm telescope and also at the "Felix Aguilar" Observatory (San Juan) using the "Perrine" 76 cm telescope. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1 A1 --- Front *Asterisk, "*" if this is a "front-side" star 2 1X --- --- Blank 3- 8 A6 --- HD *Henry Draper (HD) number 9- 1X --- --- Blank 10-13 A4 --- LS *Luminous Star (LS) number 14 1X --- --- Blank 15-22 A8 --- Fein *Identification from Feinstein, et al. 23-27 F5.2 % P_V Percentage of polarization in V 28-31 F4.2 % e_P_V Error in P_V 32-37 F6.1 deg PA_V Equatorial position angle in V 38-42 F5.2 deg e_PA_V Error in PA_V 43-47 F5.2 % P_B Percentage of polarization in B 48-51 F4.2 % e_P_B Error in P_B 52-57 F6.1 deg PA_B Equatorial position angle in B 58-62 F5.2 deg e_PA_B Error in PA_B -------------------------------------------------------------------------------- Notes for file: table1.dat -------------------------------------------------------------------------------- Front: "Front-side" stars are 22 stars determined to be cluster members and which appear to be least affected by reddening HD: One star is identified as "RT Car", instead LS: Reference: Stephenson & Sanduleak 1971 Fein: Identification from Feinstein, Marraco & Muzzio [1973, A&AS, 12, 331], Feinstein, Marraco & Forte [1976, A&AS, 24, 389], Feinstein, Fitzgerald & Moffat [1980, AJ, 85, 708] and Feinstein [1982, AJ, 87, 1012]: 14-, 15-, 16- and C- indicate respectively Tr 14, Tr 15, Tr 16 and Collinder 228; SRN- from van den Bergh & Herbst (1975). -------------------------------------------------------------------------------- Comments for file: table2.dat -------------------------------------------------------------------------------- The data for each star in Table 2 is arranged in groups of 5, one each for wavelengths 0.374, 0.443, 0.563, 0.670, and 0.792 um, respectively. The first record in a group contains the identification, and each group is separated by a blank line. See the example below. Stars 15-23 and 15-5 do not have data for 0.374 um. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1 A1 --- Front Asterisk, "*" if this is a "front-side" star 2 1X --- --- Blank 3- 8 A6 --- HD *Henry Draper (HD) number 9 1X --- --- Blank 10-13 A4 --- LS *Luminous Star (LS) number 14 1X --- --- Blank 15-22 A8 --- Fein *Identification from Feinstein, et al. 23-27 F5.3 um lam Wavelength 28-32 F5.2 % P_lam Percentage of polarization in lambda 33-37 F5.2 % e_P_lam Error in P_lam 38-43 F6.1 deg PA_lam Equatorial position angle in lambda 44-47 F4.1 deg e_PA_lam Error in PA_lam -------------------------------------------------------------------------------- Notes for file: table2.dat -------------------------------------------------------------------------------- Front: "Front-side" stars are 22 stars determined to be cluster members and least affected by reddening HD: One star is identified as "RT Car", instead LS: Reference: Stephenson & Sanduleak 1971 Fein: Identification from Feinstein, Marraco & Muzzio [1973, A&AS, 12, 331], Feinstein, Marraco & Forte [1976, A&AS, 24, 389], Feinstein, Fitzgerald & Moffat [1980, AJ, 85, 708] and Feinstein [1982, AJ, 87, 1012]: 14-, 15-, 16- and C- indicate respectively Tr 14, Tr 15, Tr 16 and Collinder 228; FO- from Forte & Orsatti (1981) -------------------------------------------------------------------------------- Comments for file: table4.dat -------------------------------------------------------------------------------- Table 4 lists results for stars with two-color polarization data. Together with Table 5, these data represent the observed polarization of the intracluster material. Note that neither Table 4 nor 5 include data for the "frontside" stars, as the residual reddening and polarizations for those stars are meaningless. Note also that the errors quoted for the intracluster polarization in Tables 4 and 5 are internal errors. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 6 A6 --- HD *Henry Draper (HD) number 7 1X --- --- Blank 8-11 A4 --- LS *Luminous Star (LS) number 12 1X --- --- Blank 13-20 A8 --- Fein *Identification from Feinstein, et al. 21-25 F5.2 --- E(B-V)o []? Observed B-V color excess 26-30 F5.2 --- E(B-V)f []? Foreground B-V color excess 31-35 F5.2 --- E(B-V)i []? Intracluster B-V color excess 36-41 F6.2 % P_V Observed polarization in V 42-45 F4.2 % e_P_V Error in observed P_V 46-52 F7.1 deg PA_V Observed equatorial position angle in V 53-57 F5.1 deg e_PA_V Error in observed PA_V 58-63 F6.2 % P_Vf Foreground polarization in V 64-70 F7.1 deg PA_Vf Foreground equatorial position angle in V 71-76 F6.2 % P_Vi Intracluster polarization in V 77-80 F4.2 % e_P_Vi Error in intracluster P_Vi 81-87 F7.1 deg PA_P_Vi Intracluster equatorial position angle in V 88-92 F5.1 deg e_PA_P_Vi Error in intracluster PA_P_Vi -------------------------------------------------------------------------------- Notes for file: table4.dat -------------------------------------------------------------------------------- HD: One star is identified as "RT Car", instead LS: Reference: Stephenson & Sanduleak 1971 Fein: Identification from Feinstein, Marraco & Muzzio [1973, A&AS, 12, 331], Feinstein, Marraco & Forte [1976, A&AS, 24, 389], Feinstein, Fitzgerald & Moffat [1980, AJ, 85, 708] and Feinstein [1982, AJ, 87, 1012]: 14-, 15-, 16- and C- indicate respectively Tr 14, Tr 15, Tr 16 and Collinder 228; FO- from Forte & Orsatti (1981) SRN- from van den Bergh & Herbst (1975) -------------------------------------------------------------------------------- Comments for file: table5.dat -------------------------------------------------------------------------------- The data for each star in Table 5 is arranged in groups of 5, one each for wavelengths 0.374, 0.443, 0.563, 0.670, and 0.792 um, respectively. The first record in a group contains the identification, and each group is separated by a blank line. See the example below. Stars 15-23 and 15-5 do not have data for 0.374 um. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table5.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 2X --- --- Blank 3- 8 A6 --- HD *Henry Draper (HD) number 9 1X --- --- Blank 10-13 A4 --- LS *Luminous Star (LS) number 14 1X --- --- Blank 15-22 A8 --- Fein *Identification from Feinstein, et al. 23-27 F5.3 um lam Wavelength 28-32 F5.2 % P_lam Percentage of polarization in lambda 33-37 F5.2 % e_P_lam Error in P_lam 38-43 F6.1 deg PA_lam Equatorial position angle in lambda 44-47 F4.1 deg e_PA_lam Error in PA_lam -------------------------------------------------------------------------------- Notes for file: table5.dat -------------------------------------------------------------------------------- HD: One star is identified as "RT Car", instead LS: Reference: Stephenson & Sanduleak 1971 Fein: Identification from Feinstein, Marraco & Muzzio [1973, A&AS, 12, 331], Feinstein, Marraco & Forte [1976, A&AS, 24, 389], Feinstein, Fitzgerald & Moffat [1980, AJ, 85, 708] and Feinstein [1982, AJ, 87, 1012]: 14-, 15-, 16- and C- indicate respectively Tr 14, Tr 15, Tr 16 and Collinder 228; FO- from Forte & Orsatti (1981) -------------------------------------------------------------------------------- Comments for file: table6.dat -------------------------------------------------------------------------------- Table 6 contains results for those nonfrontside stars with five-color polarimetric data. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table6.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 6 A6 --- HD *Henry Draper (HD) number 7 1X --- --- Blank 8-11 A4 --- LS *Luminous Star (LS) number 12 1X --- --- Blank 13-20 A8 --- Fein *Identification from Feinstein, et al. 21-25 F5.2 --- Disp_O *Observed dispersion of position angle 26-31 F6.2 --- Disp_I *Intracluster dispersion of position angle 32 A1 --- u_Disp_I *See notes 33-38 F6.3 um lam_O Observed wavelength of maximum polarization 39-43 F5.3 um e_lam_O Error in lam_O 44-49 F6.2 % P_O Observed polarization 50-53 F4.2 % e_P_O Error in P_O 54-59 F6.2 % sig_O Observed unit wgt error, least-squares fit 60-65 F6.3 um lam_I Intracluster wavelength of max. polarization 66-70 F5.3 um e_lam_I Error in lam_I 71-76 F6.2 % P_I Intracluster polarization 77- A1 --- u_P_I A colon, ':', for one star, Tr15-16 (RT Car) 78-80 F3.2 % e_P_I []? Error in P_I (null for one star, Tr15-16) 81-86 F6.2 % sig_I Intraclus. unit wgt error, least-squares fit -------------------------------------------------------------------------------- Notes for file: table6.dat -------------------------------------------------------------------------------- HD: One star is identified as "RT Car", instead LS: Reference: Stephenson & Sanduleak 1971 Fein: Identification from Feinstein, Marraco & Muzzio [1973, A&AS, 12, 331], Feinstein, Marraco & Forte [1976, A&AS, 24, 389], Feinstein, Fitzgerald & Moffat [1980, AJ, 85, 708] and Feinstein [1982, AJ, 87, 1012]: 14-, 15-, 16- and C- indicate respectively Tr 14, Tr 15, Tr 16 and Collinder 228 Disp_O: Observed dispersion of position angle normalized by the average of the position angle errors Disp_I: Intracluster dispersion of position angle normalized by the average of the position angle errors u_Disp_I: A colon, ':', flags two stars that have computed intracluster P(max) < 0.5%, and, hence, small intracluster polarizations in relation to the external errors. The authors have chosen not to extract results from these stars. -------------------------------------------------------------------------------- ================================================================================ (End) Lee Brotzman [ADS] 26-Feb-1995