J/ApJS/212/15 Polarized NVSS sources SEDs (Farnes+, 2014)
A broadband polarization catalog of extragalactic radio sources.
Farnes J.S., Gaensler B.M., Carretti E.
<Astrophys. J. Suppl. Ser. 212, 15 (2014)>
=2014ApJS..212...15F 2014ApJS..212...15F
ADC_Keywords: Polarization ; Energy distributions ; Radio sources ; Surveys
Keywords: astronomical databases: miscellaneous ; catalogs ; magnetic fields ;
polarization ; survey
Abstract:
An understanding of cosmic magnetism requires converting the
polarization properties of extragalactic radio sources into the
rest-frame in which the corresponding polarized emission or Faraday
rotation is produced. Motivated by this requirement, we present a
catalog of multiwavelength linear polarization and total intensity
radio data for polarized sources from the NRAO VLA Sky Survey. We
cross-match these sources with a number of complementary measurements
--combining data from major radio polarization and total intensity
surveys such as AT20G, B3-VLA, GB6, NORTH6CM, Texas, and WENSS,
together with other polarization data published over the last 50
years. For 951 sources, we present spectral energy distributions
(SEDs) in both fractional polarization and total intensity, each
containing between 3 and 56 independent measurements from 400MHz to
100GHz. We physically model these SEDs, and where available provide
the redshift of the optical counterpart. For a superset of 25649
sources we provide the total intensity spectral index, α.
Objects with steep versus flat α generally have different
polarization SEDs: steep-spectrum sources exhibit depolarization,
while flat-spectrum sources maintain constant polarized fractions over
large ranges in wavelength. This suggests the run of polarized
fraction with wavelength is predominantly affected by the local source
environment, rather than by unrelated foreground magnetoionic
material. In addition, a significant fraction (21%) of sources exhibit
"repolarization," which further suggests that polarized SEDs are
affected by different emitting regions within the source, rather than
by a particular depolarization law. This has implications for the
physical interpretation of future broadband polarimetric surveys.
Description:
We have collected data from throughout the literature at many
different observing frequencies (0.4-100GHz).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 480 37543 Full catalog (except SED part, which are in the
"pol.dat" and "flux.dat" files)
pol.dat 37 43040 Polarized spectral energy distribution
flux.dat 28 88014 Total intensity spectral energy distribution
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See also:
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
VIII/62 : The Westerbork Northern Sky Survey (Leiden, 1998)
VIII/42 : Texas Survey of radio sources at 365MHz (Douglas+ 1996)
VIII/40 : GB6 catalog of radio sources (Gregory+ 1996)
VIII/13 : A new catalog of 53522 4.85GHz sources (Becker+ 1991)
VII/6 : Polarization of Extragalactic Radio Sources (Eichendorf+ 1980)
J/A+A/559/A27 : RM Synthesis of 33 sources around M31 (Giessubel+, 2013)
J/MNRAS/429/2080 : Lockman Hole 10C sources spectral indices (Whittam+, 2013)
J/AJ/144/105 : MOJAVE. VIII. Faraday rotation in AGN jets. (Hovatta+, 2012)
J/ApJ/732/45 : VLA fluxes for AT20G radio galaxies (Sajina+, 2011)
J/MNRAS/402/2403 : Australia Telescope 20GHz Survey, AT20G (Murphy+, 2010)
J/MNRAS/401/1388 : Radio polarization of WMAP point sources (Jackson+, 2010)
J/ApJ/714/1689 : DRAO ELAIS N1 catalog (Grant+, 2010)
J/ApJ/702/1230 : Rotation measure image of the sky (Taylor+, 2009)
J/MNRAS/386/1881 : New pulsar rotation measures (Noutsos+, 2008)
J/MNRAS/360/1305 : Polarization of extragalactic sources (Roy+, 2005)
J/PASJ/55/351 : ATCA observations of 202 compact radio sources (Tingay+, 2003)
J/A+A/406/579 : B3-VLA sample. III. Polarisation (Klein+, 2003)
J/A+A/363/141 : Radio-loud galaxies in the ROSAT survey. IV. (Reich+, 2000)
J/A+AS/135/571 : Extragalactic radio sources polarization (Zukowski+, 1999)
J/ApJS/45/97 : Radio Sources Faraday Rotation (Simard-Normandin+ 1981)
J/A+AS/39/379 : Linear Polarization of radio sources (Tabara+ 1980)
http://sifa.org.au/Polcat : SIfA (Sydney Institute for Astronomy) POLCAT page
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Seq [1/37543] Running sequence number (Source_Num)
7- 19 A13 --- NVSS Source name (HHMMSS+DDMMSS; J2000)
(Source_Name) (1)
21- 22 I2 h RAh NVSS hour of right ascension (J2000) (RA_str)
23 A1 --- --- [h]
24- 25 I2 min RAm NVSS minute of right ascension (J2000) (RA_str)
26 A1 --- --- [m]
27- 31 F5.2 s RAs NVSS second of right ascension (J2000) (RA_str)
32 A1 --- --- [s]
34 A1 --- DE- NVSS sign of declination (J2000) (DEC_str)
35- 36 I2 deg DEd NVSS degree of declination (J2000) (DEC_str)
37 A1 --- --- [d]
38- 39 I2 arcmin DEm NVSS arcminute of declination (J2000) (DEC_str)
40 A1 --- --- [m]
41- 44 F4.1 arcsec DEs NVSS arcsecond of declination (J2000) (DEC_str)
45 A1 --- --- [0]
47- 56 F10.6 deg RAdeg NVSS right ascension (J2000) (RA)
58- 67 F10.6 deg DEdeg NVSS declination (J2000) (DEC)
69- 77 F9.4 deg GLON [-180/180] NVSS Galactic longitude (G_lon)
79- 86 F8.4 deg GLAT [-90/90] NVSS Galactic latitude (G_lat)
88- 89 I2 --- Np [1/56] Number of polarized data (Num_Data)
91- 92 I2 --- Nf [1/12] Number of total intensity data
(NumDataI)
94- 98 A5 --- Type The selected polarization SED model
classification (Depol_Type) (2)
100-108 A9 --- Phys The selected physical model classification
(Depol_Physics) (2)
110-117 F8.3 --- c1 [-5/2059]?=- Coefficient c1 for the
selected polarization SED model (c1) (3)
119-124 F6.3 --- c2 [-4.2/54]?=- Coefficient c2 for the
selected polarization SED model (c2) (3)
126-131 F6.3 --- c3 [2.1/62]?=- Coefficient c3 for the
selected polarization SED model (c3) (3)
133-137 F5.3 --- c4 [0.4/5.1]?=- Coefficient c4 for the
selected polarization SED model (c4) (3)
139-146 F8.3 --- e_c1 ?=- Error in coefficient c1 for the selected
polarization SED model (c1_err) (3)
148-153 F6.3 --- e_c2 ?=- Error in coefficient c2 for the
selected polarization SED model (c2_err) (3)
155-160 F6.3 --- e_c3 ?=- Error in coefficient c3 for the
selected polarization SED model (c3_err) (3)
162-166 F5.3 --- e_c4 ?=- Error in coefficient c4 for the
selected polarization SED model (c4_err) (3)
168-172 F5.3 --- DKS [0.07/0.5]?=- Depolarization Kolmogorov-Smirnov
statistic (Depol_KS) (4)
174-178 F5.3 --- pDKS [0.01/0.2]?=- Depolarization p value from the
KS statistic (DepolKSPval) (4)
180-185 F6.3 --- chi2D [0/100]?=- Depolarization reduced χ2
(Depol_Chi2) (4)
187-191 F5.3 --- pchi2D [0/1]?=- Depolarization p value from the
χ2 statistic (DepolChi2Pval) (4)
193 I1 --- Q [1/3] Quality flag (1="accept") (Data_Flag) (5)
195-201 F7.3 [%] bc1 [-25/142]?=- Polarization spectral index
coefficient, c1 (PolBetac1) (6)
203-209 F7.3 --- beta [-85/19]?=- Polarization spectral index β
(Pol_Beta) (6)
211-217 F7.3 --- e_beta [0/1000]?=- Error in the polarization
spectral index β (PolBetaerr)
219-224 F6.3 --- chi2B [0/100]?=- The reduced χ2
(PolBetaChi2) (7)
226-230 F5.3 --- pchi2B [0/1]?=- The p value from the χ2
statistic (PolBetaChi2_Pval) (7)
232-236 F5.3 --- BKS [0/0.6]?=- The Kolmogorov-Smirnov statistic
(PolBetaKS) (7)
238-242 F5.3 --- pBKS [0/0.2]?=- The p value from the KS statistic
(PolBetaKS_Pval) (7)
244-249 F6.4 --- z [0/5.3]?=- Redshift of the source from H12 (8)
251-256 F6.4 --- e_z [0/1]?=- z uncertainty (z_err)
258-267 A10 --- Class Classification of the object type from H12
(Selected_Obj) (8)
269 A1 --- Icl The selected total intensity spectral index
classification (I_Class) (9)
271-277 F7.3 [mJy] d1 [-26/31]?=- Spectral index coefficient log(d1)
(Ialphad1) (3)
279-284 F6.3 --- d2 [-4/3]?=- Total intensity spectral index
α (I_alpha)
286-291 F6.3 --- d3 [-2/0]?=- Spectral index coefficient d3
(Ialphad3) (3)
293-297 F5.3 [mJy] e_d1 ?=- log(d1) uncertainty (Ialphad1_err) (3)
299-303 F5.3 --- e_d2 ?=- d2 uncertainty (Ialphaerr)
305-309 F5.3 --- e_d3 ?=- d3 uncertainty (Ialphad3_err) (3)
311-316 F6.3 --- chi2I [0/100]?=- Spectral Index reduced χ2 for
the regular power law model (I_Chi2) (10)
318-323 F6.3 --- chi2Ic [0/100]?=- Spectral Index reduced χ2 for
the curved power law model (IChi2Curved) (10)
325-329 F5.3 --- pI [0/1]?=- Spectral Index p value for the regular
power law model (I_Pval) (11)
331-335 F5.3 --- pIc [0/1]?=- Spectral Index p value for the curved
power law model (IPvalCurved) (11)
337-344 F8.3 rad/m2 RM [-579/599]?=- Broadband Faraday Rotation Measure
(RM) calculated using the EVPA vs λ2
data (RM_Broad)
346-351 F6.3 rad/m2 e_RM [0/67]?=- RM uncertainty (RMBroaderr)
353-359 F7.3 deg EVPA [0/180]?=- Intrinsic Electric Vector Polarization
Angle (EVPA) calculated using the EVPA
vs λ2 data (EVPA_Broad)
361-366 F6.3 deg e_EVPA ?=- EVPA uncertainty (EVPABroaderr)
368-373 F6.3 --- chi2RM [0/100]?=- Broadband RM reduced χ2
(RMBroadChi2) (12)
375-379 F5.3 --- pRM [0/1]?=- Broadband RM p value
(RMBroadPval) (12)
381-386 F6.1 rad/m2 NRM [-719/757] NVSS RM from T09 (NVSS_RM) (13)
388-391 F4.1 rad/m2 e_NRM [0.1/55] NRM uncertainty (NVSSRMerr)
393-399 F7.1 mJy I [5.2/71633] NVSS total intensity (Stokes I)
from T09 (13)
401-405 F5.1 mJy e_I [0.4/901] I uncertainty (I_err)
407-413 F7.2 mJy PI [2/1346] NVSS polarized intensity,
P=(Q2+U2), from T09 (13)
415-419 F5.2 mJy e_PI [0.1/52] PI uncertainty (P_err)
421-426 F6.2 % Pol [0.5/180] NVSS fractional polarization,
Π=(Q2+U2)/I, from T09 (13)
428-432 F5.2 % e_Pol [0.1/20] PI uncertainty (PI_err)
434 A1 --- l_amaj Upper limit flag amaj (Majoraxislimit)
436-440 F5.1 arcsec amaj [0/127.4] NVSS major axis size (Cat. VIII/65)
(Major_axis)
442-445 F4.1 arcsec e_amaj [0/13]?=- amaj uncertainty (Majoraxiserr)
447 A1 --- l_bmin Upper limit flag on bmin (Minoraxislimit)
449-453 F5.1 arcsec bmin [0/127.3] NVSS minor axis size (Cat. VIII/65)
455-457 F3.1 arcsec e_bmin [0/8]?=- bmin uncertainty (Minoraxiserr)
459-463 F5.1 deg PA [-90/90]?=- NVSS position angle (Cat. VIII/65)
465-468 F4.1 deg e_PA [0/90]?=- PA uncertainty (NVSSPAerr)
470-473 F4.1 [W/Hz] L1.4 [21/29.5]?=- Log of the non-thermal rest-frame
spectral luminosity at 1.4GHz logLν(1.4GHz)
475-478 F4.1 [W/Hz] e_L1.4 [4.4/31]?=- L1.4 uncertainty (L_err)
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Note (1): Source name in the original NVSS catalog of Condon et al.
(1998, Cat. VIII/65).
Note (2): Table 7: selection of a Depol_Physics Classification, Using Depol_Type
and the ci Coefficients:
-----------------------------------------------
Depol_Type Equation num C2 Depol_Physics
-----------------------------------------------
gauss (5) ≤7.5 burn
gauss (5) >7.5 peaked
power (6) >0 increase
power (6) ≤0 tribble
gau+t (7) --- mantovani
-----------------------------------------------
Note (3): Table 8: Units of the ci and di coefficients as per the
selected equation:
---------------------------------------------------------------
Eq_num c1 c2 c3 C4 d1 d2 d3
---------------------------------------------------------------
(5) gauss % cm cm N/A --- --- ---
(6) power [%] unitless N/A N/A --- --- ---
(7) gau+t % cm cm % --- --- ---
(8) power --- --- --- --- mJy unitless N/A
(9) cpower --- --- --- --- mJy unitless unitless
---------------------------------------------------------------
The equations express the variation with the wavelength of the
polarisation (Eqs.5,6,7) and of the total intensity (Eqs.8,9):
(5): Π = c1 exp[-(λ-c2)2/(2c3)]
(6): Π = 10c1λc2
(7): Π = c1 exp[-(λ-c2)2/(2c3)] + c4
(8): I = d1 νd2
(9): I = d1 (ν/1.4GHz)[d2+d3.ln(ν/1.4GHz)]
Note (4): for the selected polarization SED model and the polarized fraction
vs λ data.
Note (5): A data quality flag that describes the model fit of an SED,
calculated based on the combination of the other statistical tests is
provided as an indicative measure only. Values are:
1 = "accept"
2 = "caution"
3 = "poor".
Note (6): Polarization spectral index such that: Π=10c1λβ.
Note (7): for the polarization spectral index and the polarized fraction
vs λ data.
Note (8): H12 = Hammond et al. 2012 (1209.1438). Classes include
QSO, BLLac, GALAXYn RadioG, Seyfert_1 Seyfert_2, etc.
Note (9): selected total intensity spectral index classification as follows:
R = regular power law
C = curved power law
2 = two-point spectral index
Note (10): Fit to the total intensity vs frequency data.
Note (11): And the total intensity vs frequency data
Note (12): For the selected broadband RM model and the EVPA vs λ2 data.
Note (13): T09 = Taylor et al. (2009, Cat. J/ApJ/702/1230).
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Byte-by-byte Description of file: pol.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- Seq [1/37543] Running sequence number (Source_Num)
7- 11 F5.2 cm lambda [0.3/74.2] Raw polarization wavelength data
(Lambda)
13- 18 F6.2 % Pol [0.1/180] Raw polarization fraction data
(Pol_Frac)
20- 25 F6.2 % e_Pol [0.02/20]?=999.9 Raw polarization fraction
error data (PolFracerr)
27- 31 F5.1 deg PA [0/194.1]? Raw polarization angle data (Pol_Angle)
33- 37 F5.1 deg e_PA [0/131]? Raw polarization angle error data
(PolAngleerr)
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Byte-by-byte Description of file: flux.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- Seq [1/37543] Running sequence number (Source_Num)
7- 11 F5.2 cm lambda [1.5/92] Raw total intensity wavelength data
(I_Lambda)
13- 20 F8.1 mJy Flux [5.2/321870] Raw total intensity flux density
data (I_Flux)
22- 28 F7.1 mJy e_Flux [0.4/32187] Raw total intensity flux density
error data (IFluxerr)
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History:
13-May-2014: copied at http://sifa.org.au/Polcat (PolCat_ApJ.tar.gz)
(End) Emmanuelle Perret [CDS] 13-May-2014