Search

Start Over Subject polarimetry Validation Level 2
111. Linear and circular polarisation spectra of 2 stars
ID:
ivo://CDS.VizieR/J/A+A/531/A25
Title:
Linear and circular polarisation spectra of 2 stars
Short Name:
J/A+A/531/A25
Date:
21 Oct 2021
Publisher:
CDS
Description:
The identification of the carriers of diffuse interstellar bands (DIBs) remains one of the long-standing mysteries in astronomy. The detection of a polarisation signal in a DIB profile can be used to distinguish between a dust or gas-phase carrier. The polarisation profile can give additional information on the grain or molecular properties of the absorber. The aim is to measure the polarisation efficiency of the carriers of the diffuse interstellar bands.
112. Linear polarization catalog toward HD 62542
ID:
ivo://CDS.VizieR/J/ApJS/141/469
Title:
Linear polarization catalog toward HD 62542
Short Name:
J/ApJS/141/469
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have obtained linear polarization measurements of stars along the western side of the IRAS Vela Shell toward HD 62542. From 16 CCD fields distributed along the ionization front (I-front) we have built a catalog of 856 objects with polarization signal-to-noise ratio larger than 10. We detect very significant levels of polarization and hence an appreciable magnetic field throughout the region. Composite polarization maps around the I-front are shown. In some regions the polarization vectors are parallel to the I-front, but a perpendicular trend is also evident along parts of the front. In addition, the polarization pattern seems to be affected by gas streaming inside the cloud. The observations were made using a CCD imaging polarimeter attached to the 1.5m Telescope of Cerro Tololo Inter-American Observatory (CTIO), Chile. The data were collected in 1991 December and 1992 December.
113. Linear polarization measurements for 5070 stars
ID:
ivo://CDS.VizieR/II/178
Title:
Linear polarization measurements for 5070 stars
Short Name:
II/178
Date:
21 Oct 2021
Publisher:
CDS
Description:
The authors have collected and collated measurements of linear polarization of starlight from Hiltner, Smith, Hall, Behr, Appenzeller, Mathewson and Ford, Klare et al., and Schroeder. These are presented in a catalog for stars with reliable distances that lists the Stokes parameters Q and U. The galactic latitude and longitude and distance are also given. See the documentation by Nancy G. Roman, either in plain ascii (file adc.doc), or in LaTeX (doc.tex)
114. Linear polarization of AGN jets at 15GHz
ID:
ivo://CDS.VizieR/J/AJ/130/1389
Title:
Linear polarization of AGN jets at 15GHz
Short Name:
J/AJ/130/1389
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present first-epoch, milliarcsecond-scale linear polarization images at 15GHz of 133 jets associated with active galactic nuclei (AGNs) from the MOJAVE (Monitoring of Jets in Active Galactic Nuclei with VLBA Experiments) survey. MOJAVE is a long-term observational program to study the structure and evolution of relativistic outflows in AGNs. The sample consists of all known AGNs with Galactic latitude |b|>2.5{deg}, J2000.0 declination greater than -20{deg} and correlated 15GHz Very Long Baseline Array (VLBA) flux density exceeding 1.5Jy (2Jy for sources below the celestial equator) at any epoch during the period 1994-2003.
115. Linear polarization of nearby bright stars
ID:
ivo://CDS.VizieR/J/MNRAS/405/2570
Title:
Linear polarization of nearby bright stars
Short Name:
J/MNRAS/405/2570
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report observations of the linear polarization of a sample of 49 nearby bright stars measured to sensitivities of between ~1 and ~4x10^-6^. The majority of stars in the sample show measurable polarization, but most polarizations are small with 75 per cent of the stars having P<2x10^-5^.
116. Linear Polarization of radio sources
ID:
ivo://CDS.VizieR/J/A+AS/39/379
Title:
Linear Polarization of radio sources
Short Name:
J/A+AS/39/379
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalogue is a compilation of all the data of linear polarization of radio sources published prior to December 1978. The catalogue contained 7224 data for 1510 radio sources. Polarization parameters derived from the data are also tabulated with other physical parameters.
117. Lines unaffected by polarization
ID:
ivo://CDS.VizieR/J/A+AS/103/293
Title:
Lines unaffected by polarization
Short Name:
J/A+AS/103/293
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
118. LMC and Cen A 1.3-10GHz polarization behavior
ID:
ivo://CDS.VizieR/J/ApJ/825/59
Title:
LMC and Cen A 1.3-10GHz polarization behavior
Short Name:
J/ApJ/825/59
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a broadband polarization analysis of 36 discrete polarized radio sources over a very broad, densely sampled frequency band. Our sample was selected on the basis of polarization behavior apparent in narrowband archival data at 1.4GHz: half the sample shows complicated frequency-dependent polarization behavior (i.e., Faraday complexity) at these frequencies, while half shows comparatively simple behavior (i.e., they appear Faraday simple). We re-observed the sample using the Australia Telescope Compact Array in full polarization, with 6GHz of densely sampled frequency coverage spanning 1.3-10GHz. We have devised a general polarization modeling technique that allows us to identify multiple polarized emission components in a source, and to characterize their properties. We detect Faraday complex behavior in almost every source in our sample. Several sources exhibit particularly remarkable polarization behavior. By comparing our new and archival data, we have identified temporal variability in the broadband integrated polarization spectra of some sources. In a number of cases, the characteristics of the polarized emission components, including the range of Faraday depths over which they emit, their temporal variability, spectral index, and the linear extent of the source, allow us to argue that the spectropolarimetric data encode information about the magneto-ionic environment of active galactic nuclei themselves. Furthermore, the data place direct constraints on the geometry and magneto-ionic structure of this material. We discuss the consequences of restricted frequency bands on the detection and interpretation of polarization structures, and the implications for upcoming spectropolarimetric surveys.
119. Local Bubble & Gould Belt polarization
ID:
ivo://CDS.VizieR/J/MNRAS/483/299
Title:
Local Bubble & Gould Belt polarization
Short Name:
J/MNRAS/483/299
Date:
21 Oct 2021
Publisher:
CDS
Description:
We create and analyse the largest up-to-date all-sky compilation of the interstellar optical polarization data supplemented by the reddening data This compilation includes 13 data sources with optical interstellar linear polarization for 3871 Gaia DR2 and Hipparcos stars within 500pc, which do not exhibit a considerable intrinsic polarization. These data are analysed together with five 3D maps and models of the reddening E(B-V). We consider variations of the polarization degree P, position angle theta, and polarization efficiency P/E(B-V) with Galactic coordinates, distance R, and dereddened colour. P shows a maximum at the Gould Belt mid-plane. P/R drops in the Local Bubble by several times defining a boundary of the Bubble at P=0.1 per cent. All the data sources of the reddening, except Lallement et al., show a drop of P/E(B-V) in the Bubble. The spatial- and colour-dependent variations of P and E(B-V) outside the Bubble compensate each other, resulting in a nearly constant P/E(B-V). A giant envelope of aligned dust dominates at middle and high latitudes outside the Bubble. The Markkanen's cloud, the North Polar Spur, and some other filaments are parts of this envelope.
120. Lockman Hole Polarised Sources at 1.4GHz
ID:
ivo://CDS.VizieR/J/A+A/653/A155
Title:
Lockman Hole Polarised Sources at 1.4GHz
Short Name:
J/A+A/653/A155
Date:
21 Oct 2021
Publisher:
CDS
Description:
In the context of structure formation and galaxy evolution, the contribution of magnetic fields is not well understood. Feedback processes originating from active galactic nucleus (AGN) activity and star formation can be actively influenced by magnetic fields, depending on their strength and morphology. One of the best tracers of magnetic fields is polarised radio emission. Tracing this emission over a broad redshift range therefore allows an investigation of these fields and their evolution. We aim to study the nature of the faint, polarised radio source population whose source composition and redshift dependence contain information about the strength, morphology, and evolution of magnetic fields over cosmic timescales. We use a 15-pointing radio continuum L-band mosaic of the Lockman Hole, observed in full polarisation, generated from archival data of the Westerbork Synthesis Radio Telescope (WSRT). The data were analysed using the rotation measure synthesis technique. We achieved a noise of 7uJy/beam in polarised intensity, with a resolution of 15". Using infrared and optical images and source catalogues, we were able to cross-identify and determine redshifts for one-third of our detected polarised sources. Results. We detected 150 polarised sources, most of which are weakly polarised with a mean fractional polarisation of 5.4%. No source was found with a fractional polarisation higher than 21%. With a total area of 6.5deg^2^ and a detection threshold of 6.25{sigma}, we find 23 polarised sources per deg^2^. Based on our multi-wavelength analysis, we find that our sample consists of AGN only. We find a discrepancy between archival number counts and those present in our data, which we attribute to sample variance (i.e. large-scale structures). Considering the absolute radio luminosity, we find a general trend of increased probability of detecting weak sources at low redshift and strong sources at high redshift. We attribute this trend to a selection bias. Further, we find an anti-correlation between fractional polarisation and redshift for our strong-source sample at z>=0.6. A decrease in the fractional polarisation of strong sources with increasing redshift cannot be explained by a constant magnetic field and electron density over cosmic scales; however, the changing properties of cluster environments over cosmic time may play an important role. Disentangling these two effects requires deeper and wider polarisation observations as well as better models of the morphology and strength of cosmic magnetic fields.