The jet of the BL Lacertae object PKS 0521-365 in the near-IR: MAD adaptive optics observations

Falomo, R.; Pian, E.; Treves, A.; Giovannini, G.; Venturi, T.; Moretti, Alessia; Arcidiacono, Carmelo; Farinato, Jacopo; Ragazzoni, Roberto; Diolaiti, Emiliano; Lombini, Matteo; Tavecchio, F.; Brast, R.; Donaldson, Rob; Kolb, Johann; Marchetti, Enrico; Tordo, Sebastien

doi:10.1051/0004-6361/200912077

Cited by 23 publications

(34 citation statements)

References 43 publications

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“…Also observed have been X-shaped radio sources with normal pairs of active lobes and lower surface brightness wings of emission (Leahy & Parma 1992;Dennett-Thorpe et al 2002;Cheung 2007). The 15 GHz VLA map shown in Falomo et al (2009) has a similar angular resolution (∼0.5 ) to the ALMA data and an rms noise of 200 μJy, which is sufficient to detect the perpendicular feature if it is a synchrotron emission. No hint of an elongated feature along the major axis is visible on the 15 GHz map where all the other features are clearly detected (HS, jet).…”

Section: Double Jet Dust or Free-free Emissionmentioning

confidence: 84%

Anatomy of a blazar in the (sub-)millimeter: ALMA observations of PKS 0521-365

Léon

Cortés

Guerard

et al. 2016

A&A

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Aims. We aim at analyzing the (sub-)millimeter emission in a nearby blazar, PKS 0521-365, to study the synchrotron and thermal emission in the different components detected at low frequency. Methods. We analyzed the archive public data of the ALMA Cycle 0 where PKS 0521-365 is used as a calibrator. A total of 13 projects with 23 dataset were analyzed in Bands 3, 6, and 7 and combined. The whole set of data was combined and wavelet-filtered to obtain a deep image toward PKS 0521-365, reaching a dynamic range of 47 000. The individual emission flux was measured on different dates over a period of 11 months in various components. Finally we analyzed the spectral energy distribution (SED) in each different component, including the radio jet and counter jet. Results. The point sources detected in the field follow a similar distribution to previous studies. The blazar flux shows large variation especially in Band 3. Different components are observed: core, radio jet, and newly detected counter jet, hot spot (HS), and a disky structure roughly perpendicular to the jet. The HS emission is formed by a point source surrounded by an extended emission. The viewing angle of the jet is about 30• with a Doppler factor of δ = 1.6. The HS is at a distance of 19 kpc from the center. The SED analysis shows a strong variation in the core spectral index, especially in Band 3. The two components in the radio jet have roughly a flat spectral index in Bands 6 and 7. Conclusions. The different weak and extended components in PKS 0521-365 are detected with the ALMA data. The analysis of both jets constrains the geometrical distance of the HS to the center. The SED presents a different shape in time and frequency for each component. Finally, a new structure is detected roughly perpendicular to the radio jet. and a thermal emission origin is currently favored. Further observations at higher spatial resolution are needed to confirm that hypothesis.

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Section: Double Jet Dust or Free-free Emissionmentioning

confidence: 84%

Anatomy of a blazar in the (sub-)millimeter: ALMA observations of PKS 0521-365

Léon

Cortés

Guerard

et al. 2016

A&A

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“…However, an important technical result from MAD has been to reach the diffraction limit of the VLT in K s band, 0.07 arcsec (e.g., Falomo et al 2009). In H band the performance has also been very good, regularly achieving images within a factor two of the diffraction limit (0.05 arcsec).…”

Section: Mad On the Vltmentioning

confidence: 99%

An E-ELT case study: colour–magnitude diagrams of an old galaxy in the Virgo cluster

Deep

Fiorentino

Tolstoy

et al. 2011

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One of the key science goals for a diffraction limited imager on an Extremely Large Telescope (ELT) is the resolution of individual stars down to faint limits in distant galaxies. The aim of this study is to test the proposed capabilities of a multi-conjugate adaptive optics (MCAO) assisted imager working at the diffraction limit, in IJHK s filters, on a 42m diameter ELT to carry out accurate stellar photometry in crowded images in an Elliptical-like galaxy at the distance of the Virgo cluster. As the basis for realistic simulations we have used the phase A studies of the European-ELT project, including the MICADO imager (Davies & Genzel 2010) and the MAORY MCAO module (Diolaiti 2010). We convolved a complex resolved stellar population with the telescope and instrument performance expectations to create realistic images. We then tested the ability of the currently available photometric packages STARFINDER and DAOPHOT to handle the simulated images. Our results show that deep Colour-Magnitude Diagrams (photometric error, ±0.25 at I≥27.2; H≥25. and K s ≥24.6) of old stellar populations in galaxies, at the distance of Virgo, are feasible at a maximum surface brightness, µ V ∼ 17 mag/arcsec 2 (down to M I > −4 and M H ∼ M K > −6), and significantly deeper (photometric error, ±0.25 at I≥29.3; H≥26.6 and K s ≥26.2) for µ V ∼ 21 mag/arcsec 2 (down to M I ≥ −2 and M H ∼ M K ≥ −4.5). The photometric errors, and thus also the depth of the photometry should be improved with photometry packages specifically designed to adapt to an ELT MCAO Point Spread Function. We also make a simple comparison between these simulations and what can be expected from a Single Conjugate Adaptive Optics feed to MICADO and also the James Webb Space Telescope.

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“…If the one-sidedness is due to relativistic effects, it implies that jets are still collimated and relativistic at a large distance from the core, whereas the jets in low-power sources (FRI and BL Lac) are expected to decelerate on the kpc scale. We note here that the well-known BL Lac MKN501 is one-sided on the pc scale (Doppler-boosting effect), but it shows a symmetric structure on a scale of a few tens of kpc (Giroletti et al 2004), as well as the bright BL Lac PKS 0521-365, where a bright one-sided jet is present (with emission also in the optical band), but a radio lobe on the other side is visible (Falomo et al 2009). …”

Section: Introductionmentioning

confidence: 65%

Narrow head-tail radio galaxies at very high resolution

Gregory

Feretti

Giovannini

et al. 2017

A&A

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Aims. Narrow-angle tailed (NAT) sources in clusters of galaxies can show on the large scale very narrow tails that are unresolved even at arcsecond resolution. These sources could therefore be classified as one-sided jets. The aim of this paper is to gain new insight into the structure of these sources, and establish whether they are genuine one-sided objects, or if they are two-sided sources. Methods. We observed a sample of apparently one-sided NAT sources at subarcsecond resolution to obtain detailed information on their structure in the nuclear regions of radio galaxies. Results. Most radio galaxies are found to show two-sided jets with sharp bends, and therefore the sources are similar to the more classical NATs, which are affected by strong projection effects.

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The jet of the BL Lacertae object PKS 0521-365 in the near-IR: MAD adaptive optics observations

Cited by 23 publications

References 43 publications

Anatomy of a blazar in the (sub-)millimeter: ALMA observations of PKS 0521-365

Anatomy of a blazar in the (sub-)millimeter: ALMA observations of PKS 0521-365

An E-ELT case study: colour–magnitude diagrams of an old galaxy in the Virgo cluster

Narrow head-tail radio galaxies at very high resolution

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