scholarly journals Radio jet structures at ∼100 pc and larger scales of the γ-ray-emitting narrow-line Seyfert 1 galaxy PMN J0948+0022

2019 ◽  
Vol 487 (1) ◽  
pp. 640-649 ◽  
Author(s):  
Akihiro Doi ◽  
Satomi Nakahara ◽  
Masanori Nakamura ◽  
Motoki Kino ◽  
Nozomu Kawakatu ◽  
...  
Keyword(s):  
Large Scale ◽  
Ambient Pressure ◽  
Position Angle ◽  
Host Galaxy ◽  
Narrow Line ◽  
Very Large Array ◽  
Long Baseline ◽  
Radio Lobe ◽  
Γ Ray ◽  
Very Long Baseline Array

Abstract The narrow-line Seyfert 1 (NLS1) galaxy PMN J0948+0022 is an archetype of γ-ray-emitting NLS1s in active galactic nuclei (AGNs). In this study, we investigate its radio structures using archival data obtained using the Karl G. Jansky Very Large Array (VLA) and the Very Long Baseline Array (VLBA). The new VLA images reveal an outermost radio emission separated by 9.1 arcsec. Its resolved structure and steep spectrum suggest a terminal shock in a radio lobe energized by the jet from the PMN J0948+0022 nucleus. This large-scale radio component is found at almost the same position angle as that of the pc-scale jet, indicating a stable jet direction up to ∼1 Mpc. Its apparent one-sidedness implies a moderate advancing speed (β > 0.27). The kinematic age of <1× 107 yr of the jet activity is consistent with the expected NLS1 phase of ∼107 yr in the AGN lifetime. The VLBA image reveals the jet structure at distances ranging from r = 0.82 milliarcsec to 3.5 milliarcsec, corresponding to approximately 100 pc, where superluminal motions were found. The jet width profile (∝ r1.12) and flux-density profile (∝ r−1.44) depending on the distance r along the jet suggest that the jet kinetic energy is converted to internal energy in this region. The jet is causally connected in a nearly conical streamline, which is supported by ambient pressure at 100 pc scales in the host galaxy of PMN J0948+0022.

scholarly journals The jet of the quasar 4C+21.35 from parsec to kiloparces scales and its role in high energy photon production

2014 ◽  
Vol 10 (S313) ◽  
pp. 33-38 ◽  
Author(s):  
Svetlana G. Jorstad ◽  
Alan P. Marscher ◽  
Daria A. Morozova ◽  
Vishal Bala ◽  
Ivan Agudo ◽  
...  
Keyword(s):  
Light Curve ◽  
Position Angle ◽  
High Energy ◽  
Relativistic Electrons ◽  
Microwave Background ◽  
Inverse Compton Scattering ◽  
The Core ◽  
Long Baseline ◽  
Γ Ray ◽  
Very Long Baseline Array

AbstractWe present an analysis of the parsec-scale jet structure of the quasar 4C+21.35 with a resolution of 0.1 milliarcseconds based on 63 epochs of Very Long Baseline Array observations at 43 GHz from 2007 June to 2014 May along with the Fermi LAT γ-ray light curve and multi-frequency optical photometric and polarimetric data. We find that the innermost jet of the quasar consists of a very compact core of size ~0.03 mas, as well as feature A1 located 0.16 ± 0.03 mas from the core. The distance of A1 remains fairly stable, but its position angle with respect to the core changes from -10 to +10 deg. We detect 4 superluminal knots in the inner jet with apparent speeds ranging from 10c to 20c. The first two components appeared in the jet during the high γ-ray state of the quasar from mid-2010 to early 2011, while the fourth knot appears to be connected with the γ-ray active state in late 2013 - early 2014. The first knot can be associated with the dramatic VHE flare in 2010 June and possesses an extreme Doppler factor ~60. We find that maxima in the γ-ray light curve coincide with epochs of interaction between the moving knots and the core and feature A1. This suggests that the core and A1 are recollimation shocks where γ-ray flares occur. The Chandra 0.5-6 keV image reveals the existence of X-ray emission in the kiloparsec scale jet of the quasar that can be explained via inverse Compton scattering off the cosmic microwave background by relativistic electrons if no deceleration occurs between the parsec- and kiloparsec-scale jets.

scholarly journals The radio structure of the narrow-line Seyfert 1 Mrk 783 with VLBA and e-MERLIN

2020 ◽  
Vol 499 (3) ◽  
pp. 3149-3157
Author(s):  
E Congiu ◽  
P Kharb ◽  
A Tarchi ◽  
M Berton ◽  
A Caccianiga ◽  
...  
Keyword(s):  
Position Angle ◽  
Optical Observations ◽  
Narrow Line ◽  
Radio Structure ◽  
Long Baseline ◽  
New Radio ◽  
The Galaxy ◽  
L Band ◽  
Very Long Baseline Array ◽  
Band Image

ABSTRACT In this paper, we present the analysis of new radio and optical observations of the narrow-line Seyfert 1 galaxy Mrk 783. $1.6\, \mathrm{GHz}$ observations performed with the e-MERLIN interferometer confirm the presence of the diffuse emission previously observed. The Very Long Baseline Array (VLBA) also detects the nuclear source both at $1.6\, \mathrm{GHz}$ (L band) and $5\, \mathrm{GHz}$ (C band). While the L-band image shows only an unresolved core, the C-band image shows the presence of a partially resolved structure at a position angle of 60○. The brightness temperature of the emission in both bands (${\gt}10^6\, \mathrm{K}$) suggests that it is a pc-scale jet produced by the active galactic nucleus. The relatively steep VLBA spectral index (αVLBA = 0.63 ± 0.03) is consistent with the presence of optically thin emission on milliarcsecond scales. Finally, we investigated two possible scenarios that can result in the misalignment between the kpc and pc-scale radio structure detected in the galaxy. We also analysed the optical morphology of the galaxy, which suggests that Mrk 783 underwent a merging in relatively recent times.

scholarly journals Observations of the γ-ray emitting narrow-line Seyfert 1, SBS 0846+513, and its host galaxy

2021 ◽  
Author(s):  
Timothy S Hamilton ◽  
Marco Berton ◽  
Sonia Antón ◽  
Lorenzo Busoni ◽  
Alessandro Caccianiga ◽  
...  
Keyword(s):  
Black Hole ◽  
Adaptive Optics ◽  
Host Galaxy ◽  
Narrow Line ◽  
Black Hole Mass ◽  
Residual Structure ◽  
Line Region ◽  
Resolution Imaging ◽  
Γ Ray ◽  
Adaptive Optics System

Abstract The γ-ray emitting galaxy SBS 0846 + 513 has been classified as a Narrow-Line Seyfert 1 (NLS1) from its spectroscopy, and on that basis would be thought likely to have a small central black hole hosted in a spiral galaxy. But very few of the γ-ray NLS1 have high-resolution imaging of their hosts, so it is unknown how the morphology expectation holds up for the γ-emitting class. We have observed this galaxy in the J-band with the Large Binocular Telescope’s LUCI1 camera and the ARGOS adaptive optics system. We estimate its black hole mass to lie between $4.2\times 10^7 \le \frac{\text{M}}{\text{M}_\odot } \le 9.7\times 10^7$, using the correlation with bulge luminosity, or $1.9\times 10^7 \le \frac{\text{M}}{\text{M}_\odot } \le 2.4\times 10^7$ using the correlation with Sérsic index. Our favoured estimate is 4.2 × 107M⊙, putting its mass at the high end of the NLS1 range in general but consistent with others that are γ-ray emitters. These estimates are independent of the Broad Line Region viewing geometry and avoid any underestimates due to looking down the jet axis. Its host shows evidence of a bulge + disc structure, from the isophote shape and residual structure in the nuclear-subtracted image. This supports the idea that γ-ray NLS1 may be spiral galaxies, like their non-jetted counterparts.

scholarly journals The obstructed jet in Mrk 231

2021 ◽  
Author(s):  
Ailing Wang ◽  
Tao An ◽  
Sumit Jaiswal ◽  
Prashanth Mohan ◽  
Yuchan Wang ◽  
...  
Keyword(s):  
Large Scale ◽  
Position Angle ◽  
Opening Angle ◽  
Luminous Infrared Galaxies ◽  
Multi Scale ◽  
Long Baseline ◽  
Relativistic Jet ◽  
Multi Phase ◽  
Jet Structure ◽  
Projected Distance

Abstract Mrk 231 is the closest radio-quiet quasar known and one of the most luminous infrared galaxies in the local Universe. It is characterised by the co-existence of a radio jet and powerful multi-phase multi-scale outflows, making it an ideal laboratory to study active galactic nucleus (AGN) feedback. We analyse the multi-epoch very long baseline interferometry data of Mrk 231 and estimate the jet head advance speed to be ≲ 0.013 c, suggesting a sub-relativistic jet flow. The jet position angle changes from −113○ in the inner parsec to −172○ at a projected distance of 25 parsec. The jet structure change might result from either a jet bending following the rotation of the circum-nuclear disc or the projection of a helical jet on the plane of the sky. In the large opening angle (∼60○) cone, the curved jet interacts with the interstellar medium and creates wide-aperture-angle shocks which subsequently dissipate a large portion of the jet power through radiation and contribute to powering the large-scale outflows. The low power and bent structure of the Mrk 231 jet, as well as extensive radiation dissipation, are consistent with the obstruction of the short-length jet by the host galaxy’s environment.

scholarly journals Jansky VLA observations of synchrotron emitting optical hotspots of 3C 227 and 3C 445 radio galaxies

2020 ◽  
Vol 494 (2) ◽  
pp. 2244-2253 ◽  
Author(s):  
M Orienti ◽  
G Migliori ◽  
G Brunetti ◽  
H Nagai ◽  
F D’Ammando ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Optical Emission ◽  
Position Angle ◽  
Radio Galaxies ◽  
Very Large Array ◽  
Peculiar Characteristic ◽  
Intensity Images ◽  
First Time ◽  
Shock Fronts

ABSTRACT We report results on deep Jansky Very Large Array (VLA) A-configuration observations at 22 GHz of the hotspots of the radio galaxies 3C 227 and 3C 445. Synchrotron emission in the optical on scales up to a few kpc was reported for the four hotspots. Our VLA observations point out the presence of unresolved regions with upper limit to their linear size of about 100 pc. This is the first time that such compact components in hotspots have been detected in a mini-sample, indicating that they are not a peculiar characteristic of a few individual hotspots. The polarization may reach values up to 70 per cent in compact (about 0.1 kpc scale) regions within the hotspot, indicating a highly ordered magnetic field with size up to a hundred parsecs. On larger scales, the average polarization of the hotspot component is about 30–45 per cent, suggesting the presence of a significant random field component, rather than an ordered magnetic field. This is further supported by the displacement between the peaks in polarized intensity and in total intensity images that is observed in all the four hotspots. The electric vector position angle is not constant, but changes arbitrarily in the central part of the hotspot regions, whereas it is usually perpendicular to the total intensity contours of the outermost edge of the hotspot structure, likely marking the large-scale shock front. The misalignment between X-ray and radio-to-optical emission suggests that the former is tracing the current particle acceleration, whereas the latter marks older shock fronts.

scholarly journals Variability and parsec-scale radio structure of candidate compact symmetric objects

2020 ◽  
Vol 499 (1) ◽  
pp. 1340-1355 ◽  
Author(s):  
M Orienti ◽  
D Dallacasa
Keyword(s):  
Flux Density ◽  
Expansion Velocity ◽  
Radio Structure ◽  
Very Large Array ◽  
Long Baseline ◽  
Thick Part ◽  
Thin Part ◽  
Almost All ◽  
Very Long Baseline Array ◽  
Fast Evolution

ABSTRACT We report results on multiepoch Very Large Array (VLA) and pc-scale Very Long Baseline Array (VLBA) observations of candidate compact symmetric objects (CSOs) from the faint sample of high-frequency peakers. New VLBA observations could resolve the radio structure in about 42 per cent of the observed sources, showing double components that may be either mini-lobes or core-jet structures. Almost all the sources monitored by the VLA show some variability on time-scale of a decade, and only one source does not show any significant variation. In 17 sources, the flux density changes randomly as it is expected in blazars, and in four sources the spectrum becomes flat in the last observing epoch, confirming that samples selected in the GHz regime are highly contaminated by beamed objects. In 16 objects, the pc-scale and variability properties are consistent with a young radio source in adiabatic expansion, with a steady decrease of the flux density in the optically thin part of the spectrum, and a flux density increase in the optically thick part. For these sources, we estimate dynamical ages between a few tens to a few hundred years. The corresponding expansion velocity is generally between 0.1c and 0.7c, similar to values found in CSOs with different approaches. The fast evolution that we observe in some CSO candidates suggests that not all the objects would become classical Fanaroff–Riley radio sources.

scholarly journals Uncovering the host galaxy of the γ-ray-emitting narrow-line Seyfert 1 galaxy FBQS J1644+2619

2017 ◽  
Vol 469 (1) ◽  
pp. L11-L15 ◽  
Author(s):  
F. D'Ammando ◽  
J. A. Acosta-Pulido ◽  
A. Capetti ◽  
C. M. Raiteri ◽  
R. D. Baldi ◽  
...  
Keyword(s):  
Host Galaxy ◽  
Narrow Line ◽  
Γ Ray

scholarly journals The radio properties of high-excitation radio galaxies with intermediate radio powers

2020 ◽  
Vol 494 (2) ◽  
pp. 2053-2067
Author(s):  
J C S Pierce ◽  
C N Tadhunter ◽  
R Morganti
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
High Sensitivity ◽  
Seyfert Galaxies ◽  
Radio Galaxies ◽  
Host Galaxy ◽  
High Excitation ◽  
Power Sources ◽  
Very Large Array ◽  
Extended Radio

ABSTRACT In the past decade, high-sensitivity radio surveys have revealed that the local radio active galactic nucleus population is dominated by moderate-to-low power sources with emission that is compact on galaxy scales. High-excitation radio galaxies (HERGs) with intermediate radio powers (22.5 < log (L1.4 GHz) < 25.0 W Hz−1) form an important sub-group of this population, since there is strong evidence that they also drive multiphase outflows on the scales of galaxy bulges. Here, we present high-resolution Very Large Array observations at 1.5, 4.5, and 7.5 GHz of a sample of 16 such HERGs in the local universe (z < 0.1), conducted in order to investigate the morphology, extent, and spectra of their radio emission in detail, down to sub-kpc scales. We find that the majority (56 per cent) have unresolved structures at the limiting angular resolution of the observations (∼0.3 arcsec). Although similar in the compactness of their radio structures, these sources have steep radio spectra and host galaxy properties that distinguish them from local low-excitation radio galaxies that are unresolved on similar scales. The remaining sources exhibit extended radio structures with projected diameters ∼1.4–19.0 kpc and a variety of morphologies: three double-lobed; two large-scale diffuse; one jetted and ‘S-shaped’; one undetermined. Only 19 per cent of the sample therefore exhibit the double-lobed/edge-brightened structures often associated with their counterparts at high and low radio powers: radio-powerful HERGs and Seyfert galaxies, respectively. Additional high-resolution observations are required to investigate this further, and to probe the ≲300 pc scales on which some Seyfert galaxies show extended structures.

scholarly journals The Structure and Kinematics of Envelope around Red Supergiant AH Sco Traced by SiO Masers

2008 ◽  
Vol 4 (S252) ◽  
pp. 247-248 ◽  
Author(s):  
X. Chen ◽  
Z.-Q. Shen
Keyword(s):  
Model Fitting ◽  
Position Angle ◽  
Central Star ◽  
Circumstellar Envelope ◽  
Proper Motions ◽  
3 Dimensional ◽  
Long Baseline ◽  
Elliptical Ring ◽  
Regular Variable ◽  
Very Long Baseline Array

AbstractObservations of 43 GHz v = 1, J = 1−0 SiO masers in the circumstellar envelope of the M-type semi-regular variable star AH Sco were performed with the Very Long Baseline Array (VLBA) at 2 epochs in March 2004. These high-resolution VLBA images reveal that the distribution of SiO masers is roughly on a persistent elliptical ring with the lengths of the major and minor axes of about 18.5 and 15.8 mas, respectively, along a position angle of 150°. The 3-dimensional kinematics model-fitting for proper motions and spatial distributions of maser features clearly indicates that the SiO maser shell around AH Sco was undergoing an overall contraction to the star at a velocity of 15 km s−1 at a distance of 2.26 kpc to AH Sco due to the gravitation of the central star.

scholarly journals Late-time Evolution and Modeling of the Off-axis Gamma-Ray Burst Candidate FIRST J141918.9+394036

2022 ◽  
Vol 924 (1) ◽  
pp. 16
Author(s):  
K. P. Mooley ◽  
B. Margalit ◽  
C. J. Law ◽  
D. A. Perley ◽  
A. T. Deller ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Optical Data ◽  
Host Galaxy ◽  
Opening Angle ◽  
Late Time ◽  
Gamma Ray Burst ◽  
Very Large Array ◽  
Long Baseline ◽  
New Radio ◽  
Low Metallicity

Abstract We present new radio and optical data, including very-long-baseline interferometry, as well as archival data analysis, for the luminous, decades-long radio transient FIRST J141918.9+394036. The radio data reveal a synchrotron self-absorption peak around 0.3 GHz and a radius of around 1.3 mas (0.5 pc) 26 yr post-discovery, indicating a blastwave energy ∼5 × 1050 erg. The optical spectrum shows a broad [O iii]λ4959,5007 emission line that may indicate collisional excitation in the host galaxy, but its association with the transient cannot be ruled out. The properties of the host galaxy are suggestive of a massive stellar progenitor that formed at low metallicity. Based on the radio light curve, blastwave velocity, energetics, nature of the host galaxy and transient rates, we find that the properties of J1419+3940 are most consistent with long gamma-ray burst (LGRB) afterglows. Other classes of (optically discovered) stellar explosions as well as neutron star mergers are disfavored, and invoking any exotic scenario may not be necessary. It is therefore likely that J1419+3940 is an off-axis LGRB afterglow (as suggested by Law et al. and Marcote et al.), and under this premise the inverse beaming fraction is found to be f b − 1 ≃ 280 − 200 + 700 , corresponding to an average jet half-opening angle < θ j > ≃ 5 − 2 + 4 degrees (68% confidence), consistent with previous estimates. From the volumetric rate we predict that surveys with the Very Large Array, Australian Square Kilometre Array Pathfinder, and MeerKAT will find a handful of J1419+3940-like events over the coming years.

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