J/A+A/596/A78 R-band polarization curves of 48 BL Lacs (Hovatta+, 2016)
Optical polarization of high-energy BL Lac objects.
Hovatta T., Lindfors E., Blinov D., Pavlidou V., Nilsson K., Kiehlmann S.,
Angelakis E., Fallah Ramazani V., Liodakis I., Myserlis I., Panopoulou G.V.,
Pursimo T.
<Astron. Astrophys. 596, A78 (2016)>
=2016A&A...596A..78H 2016A&A...596A..78H (SIMBAD/NED BibCode)
ADC_Keywords: BL Lac objects ; Polarization
Keywords: polarization - BL Lacertae objects: general - galaxies: jets
Abstract:
We investigate the optical polarization properties of high-energy BL
Lac objects using data from the RoboPol blazar monitoring program and
the Nordic Optical Telescope.
We wish to understand if there are differences between the BL Lac
objects that have been detected with the current-generation TeV
instruments and those objects that have not yet been detected.
We used a maximum-likelihood method to investigate the optical
polarization fraction and its variability in these sources. In order
to study the polarization position angle variability, we calculated
the time derivative of the electric vector position angle (EVPA)
change. We also studied the spread in the Stokes Q/I-U/I plane and
rotations in the polarization plane.
Description:
R-band polarization curves of a sample of 29 TeV and 19 non-TeV BL Lac
objects observed with the RoboPol instrument at Skinakas Observatory
and ALFOSC instrument at the Nordic Optical Telescope in 2014 over
several epochs. The fractional polarization (without de-biasing
applied), electric vector position angle, Stokes Q and U, and their
corresponding uncertainties are given.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
sources.dat 64 48 TeV and non-TeV sample sources
tev.dat 114 247 TeV-detected objects (29 objects)
ctrl.dat 114 201 Non-TeV objects (19 objects)
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Byte-by-byte Description of file: sources.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Type TeV or non-TeV sources
9- 18 A10 --- Name J2000 name of the source (JHHMM+DDMM)
20- 21 I2 h RAh Simbad right ascension (J2000)
23- 24 I2 min RAm Simbad right ascension (J2000)
26- 30 F5.2 s RAs Simbad right ascension (J2000)
32 A1 --- DE- Declination sign (J2000)
33- 34 I2 deg DEd Declination (J2000)
36- 37 I2 arcmin DEm Declination (J2000)
39- 42 F4.1 arcsec DEs Declination (J2000)
44- 64 A21 --- OName Alias of the name, as in Simbad
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Byte-by-byte Description of file: ctrl.dat tev.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name J2000 name of the source (JHHMM+DDMM)
12- 31 A20 --- Oname Alias of the name
33- 45 F13.5 d JD Julian date of the observation
47- 51 F5.2 % pfrac Polarization fraction
53- 57 F5.2 % e_pfrac 1-sigma uncertainty of polarization fraction
59- 65 F7.2 deg EVPA Electric vector position angle
67- 72 F6.2 deg e_EVPA 1-sigma uncertainty of EVPA
74- 81 F8.5 --- Q/I Stokes Q/I
83- 89 F7.5 --- e_Q/I 1-sigma uncertainty of Q/I
91- 98 F8.5 --- U/I Stokes U/I
100-106 F7.5 --- e_U/I 1-sigma uncertainty of U/I
108-114 A7 --- Tel Instrument used for observation
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Acknowledgements:
Talvikki Hovatta, thovatta(at)gmail.com
(End) Talvikki Hovatta [Univ. Turku, Finland] Patricia Vannier [CDS] 30-Nov-2016