J/ApJ/569/23 Optical polarisation of 2MASS QSOs (Smith+, 2002)
The optical polarization of near-infrared-selected quasi-stellar objects.
Smith P.S., Schmidt G.D., Hines D.C., Cutri R.M., Nelson B.O.
<Astrophys. J. 569, 23 (2002)>
=2002ApJ...569...23S 2002ApJ...569...23S
ADC_Keywords: Active gal. nuclei ; QSOs ; Polarization ; Photometry, infrared
Keywords: galaxies: active - galaxies: ISM - polarization - quasars: general
Abstract:
Optical broadband polarimetry is presented for near-infrared
color-selected active galactic nuclei (AGNs) classified as
quasi-stellar objects (QSOs) based on their Ks-band luminosity. More
than 10% of a sample of 70 QSOs discovered in the Two Micron All Sky
Survey (2MASS, Cat. <B/2mass>) with J-Ks>2 and MKs←23 show high
broadband linear polarization (P>3%), and values range to a maximum of
P∼11%. High polarization tends to be associated with the most luminous
objects at Ks and with QSOs having the highest near-IR to optical flux
ratios. The 2MASS QSO sample includes objects possessing a wide range
of optical spectral types. High polarization is seen in two of 22
broad emission-line (type 1) objects, but ∼1/4 of the QSOs of
intermediate spectral type (type 1.5-1.9) are highly polarized. None
of the nine QSOs classified as type 2 exhibit P>3%.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 104 101 Optical polarimetry of 2MASS Red QSOs
table2.dat 99 23 Optical polarimetry of other AGN found by 2MASS
table3.dat 79 10 Galactic interstellar polarization detected in
the fields of 2MASS AGNs
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See also:
B/2mass : The 2MASS database (IPAC/UMass, 2000)
Byte-by-byte Description of file: table1.dat table2.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- --- [2MASSI]
8- 23 A16 --- 2MASSI The 2MASSI object name
25- 29 F5.3 --- z ? Redshift from Cutri et al.
(2001, ASP Conf. Ser. 232, 78)
31- 34 A4 --- SpType Spectral classification (1)
36- 40 F5.2 mag Kmag The Ks band magnitude (2)
42- 45 F4.2 mag J-Ks The (J-Ks) color (2)
47 A1 --- l_B-Ks Limit flag on B-K
48- 51 F4.2 mag B-Ks The (B-Ks) color (2)
53- 58 F6.2 mag KMag ? The absolute Ks band magnitude
60- 63 I4 yr Obs.Y ? UT year of the observation
65- 66 I2 "month" Obs.M ? UT month of the observation
68- 69 I2 d Obs.D ? UT day of the observation
71 A1 --- f_Pol [a] a indicates that the polarization data is
an average of the previous observations
73- 77 F5.2 % Pol Degree of linear polarization (3)
79- 82 F4.2 % e_Pol The 1σ error on Polar
84- 88 F5.1 deg theta ? Polarization position angle
90- 93 F4.1 deg e_theta ? The 1σ error on theta
95-103 A9 --- Comm Comments (4)
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Note (1): Taken from Cutri et al. (2001, ASP Conf. Ser. 232, 78):
L = LINER;
S = Starburst;
1.x = objects with broad Hα emission lines, but show no
evidence of an Hβ emission line;
1.b = objects that show broad Hα, but the spectra do not extend
far enough to the blue to reach Hβ.
Note (2): Data are from the 2MASS Point Source Catalog.
Note (3): Not corrected for statistical bias.
Note (4): Comments:
2H60: Unfiltered observation obtained with the Two-Holer
photo-polarimeter using a 4" aperture at the Steward
Observatory Mt. Lemmon 1.5 m (60-inch) telescope;
2H90: Unfiltered observation obtained with the Two-Holer instrument
using a 2.9" aperture at the Bok (90-inch) telescope;
spol: Optical spectropolarimetry of 2MASSI J151653.2+190048 and
2MASSI J165939.7+183436 is reported by Smith et al.
(2000ApJ...545L..19S 2000ApJ...545L..19S).
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- --- [2MASSI]
8- 23 A16 --- 2MASSI The 2MASSI object name
25- 37 A13 --- Object The object name
39- 40 I2 h RAh Right ascension (J2000.0)
42- 43 I2 min RAm Right ascension (J2000.0)
45- 48 F4.1 s RAs Right ascension (J2000.0)
50 A1 --- DE- Declination sign (J2000.0)
51- 52 I2 deg DEd Declination (J2000.0)
54- 55 I2 arcmin DEm Declination (J2000.0)
57- 58 I2 arcsec DEs Declination (J2000.0)
60- 63 F4.2 % Pol Polarisation percentage
65- 68 F4.2 % e_Pol rms uncertainty on Pol
70- 74 F5.1 deg theta Polarization angle
76- 79 F4.1 deg e_theta rms uncertainty on theta
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 17-Jun-2002