Astrophysical Polarimetry in the Time-Domain Era

Session

Polarization and AGN and blazars

29 Aug 2022, 09:05

Politecnico di Milano - Polo territoriale di Lecco

Conveners

Polarization and AGN and blazars

• Elina Lindfors (Finnish Centre for astronomy with ESO, University of Turku)

Polarization and AGN and blazars

• Elina Lindfors (Finnish Centre for astronomy with ESO, University of Turku)

Polarization and AGN and blazars

• Elina Lindfors (Finnish Centre for astronomy with ESO, University of Turku)

Description

All sub-categories, blazars, etc.

101. Prospects for multi-wavelength polarimetry of blazars

Prof. Markus Boettcher (North-West University)

29/08/2022, 09:05

Oral

This talks provides a review of prospects for multi-wavelength polarimetry of blazars. This includes inferences from optical spectropolarimetry as well as high-energy polarimetry, with special emphasis on first results from and expectations for IXPE.

71. X-ray polarimetry of radio quiet AGN in the IXPE era

Prof. Giorgio Matt (Roma 3 University)

29/08/2022, 09:40

Oral

X-ray polarimetry is expected to contribute to our understanding
of Radio Quiet AGN in at least two ways: by constraining the geometry of the hot corona in unobscured sources, thereby providing clues to its nature; by measuring the geometrical parameters of circumnuclear matter, especially in heavily obscured sources.

In this talk, first IXPE (Imaging X-ray Polarimetry Explorer) results...

131. Jets in Blazars as seen by POLAMI: Polarization Monitoring of AGN at Millimeter Wavelengths with the IRAM 30m Telescope

Dr Ivan Agudo (Instituto de Astrofisica de Andalucia (CSIC))

29/08/2022, 10:15

Oral

A Large Program at the IRAM 30m Telescope called POLAMI observes since 2007, with a time sampling of ~2 weeks, the four Stokes parameters of the 3.5 and 1.3 mm emission of a sample of ~40 of the brighter sources in the northern sky. This contribution outlines the most salient scientific results obtained from the first detailed analysis of the data on which regards to the structure and magnetic...

85. Mapping the 3D magnetic field of AGN jets through spectropolarimetry study

Dr Alice Pasetto (IRya, National Autonomous University of Mexico)

29/08/2022, 11:00

Oral

Here, I overview one of the available techniques for the analysis of broad-band spectropolarimetric data, the Stokes QU-fitting. Since broad-band receivers have been installed at most radio facilities, the collection of radio data, both the total intensity and the linear polarization, is revealing interesting features in their spectra. The polarized light, and therefore its properties, i.e....

93. Blazars in the discovery era of X-ray polarimetry

Ioannis Liodakis (Finnish Centre for Astronomy with ESO)

29/08/2022, 11:35

Oral

High-energy polarization is an important probe of emission processes in astrophysical systems. This is particularly true for blazars where it allows us to investigate the physical conditions experienced by the most energetic particles. Until now, polarization observations have been limited to the radio-to-optical range. However, the X-ray polarization window is finally open with the recently...

94. Multi-wavelength polarization signatures as a probe for blazar flaring mechanism

Dr Haocheng Zhang (NASA GSFC/NPP Fellow)

29/08/2022, 12:10

Oral

Blazars are among the most powerful cosmic particle accelerators. They exhibit highly variable emission across the entire electromagnetic spectrum. It is often believed that the blazar flares are driven by dissipating magnetic energy in the blazar jet. Current theories suggest that both turbulence and magnetic reconnection can lead to blazar flares. This talk aims to understand the...

107. Probing particle acceleration in jets through X-ray polarimetry

Fabrizio Tavecchio (Istituto Nazionale di Astrofisica (INAF))

29/08/2022, 12:30

Oral

X-ray polarimetry allows us an unprecedented look at the structure of magnetic fields and on the processes at the base of acceleration of particles up to ultrarelativistic energies in relativistic jets. Crucial pieces of information are expected from observations of blazars of the subclass defined by a synchrotron emission extending to the X-ray band (so-called high synchrotron peak blazars,...

80. Jets, Blobs, and Circular Polarization: Using PLUTO & RADMC-3D to Model Time Domain Variability in Blazars

Dr Nicholas MacDonald (Max Planck Institute for Radio Astronomy)

29/08/2022, 12:50

Oral

Blazars are an extreme subclass of active galactic nuclei (AGN), in which an accreting supermassive black hole launches a powerful relativistic jet of magnetized plasma that is closely aligned to our line-of-sight. Blazar jets: (i) shine across the entire electromagnetic spectrum (from low-frequency radio waves to high-energy gamma-rays), (ii) exhibit dramatic flares (on time scales ranging...

123. Polarization variability in a sample of gamma-ray blazars

Jorge Otero-Santos (Instituto de Astrofisica de Canarias (IAC))

29/08/2022, 14:30

Oral

The low energy emission of AGN, from radio to optical wavelengths, is liked to the magnetic field of the jet and its synchrotron emission. Specifically, blazars show an extraordinarily high optical polarization with respect to other AGN types, with values that can reach a fraction of ~50%. As for the total emission, the polarization degree also exhibits strong variability in different time...

106. Do Narrow-Line Seyfert 1 galaxies have smaller BH masses? Spectropolarimetry to the rescue

Marzena Sniegowska (Nicolaus Copernicus Astronomical Center PAS; Center for Theoretical Physics PAS)

29/08/2022, 14:50

Oral

Black hole mass measurements for Narrow Line Seyfert 1 (NLSy1) galaxies are based on unexpectedly short time lags seen in the reverberation mapping (RM) of the Broad Line Region (BLR) campaigns. Black hole masses are estimated under the assumption of the virial factor, which depends on the geometry of BLR and the viewing angle of the source. Spectropolarimetric observations of BLR would...

124. Polarimetry of GSN 069: the source of the quasi-periodic eruptions

Dr Beatriz Agís González (Instituto de Astrofísica de Andalucía (IAA-CSIC))

29/08/2022, 15:10

Oral

GSN 069 is a high Eddington-ratio Seyfert galaxy that exhibits an unabsorbed highly variable X-ray spectrum typical of a Seyfert 1, but it does not show broad emission lines in its optical spectrum, which leads to a Seyfert 2 classification. It could be then considered as a true Seyfert 2 candidate. Those candidates are thought to accrete at low Eddington rates, unable to sustain the broad...

127. Modeling the Multi-wavelength Polarization and Spectral Energy Distributions of Blazars

Hester Schutte

29/08/2022, 15:30

Oral

In the radio through optical-UV/X-ray regime, blazars emit highly polarized (nonthermal) synchrotron emission. Emission from the dusty torus, broad line region, accretion disk and host galaxy is of thermal origin and unpolarized. In some cases, their contribution is visible in spectropolarimetry wherein the unpolarized thermal emission dilutes the synchrotron polarization. However, partially...