scholarly journals The disc-like host galaxies of radio-loud narrow-line Seyfert 1s

2019 ◽  
Vol 492 (1) ◽  
pp. 1450-1464 ◽  
Author(s):  
Alejandro Olguín-Iglesias ◽  
Jari Kotilainen ◽  
Vahram Chavushyan
Keyword(s):  
Near Infrared ◽  
Brightness Distribution ◽  
Morphological Properties ◽  
Narrow Line ◽  
Host Galaxies ◽  
Relativistic Jets ◽  
Optical Telescope ◽  
Spectrum Radio ◽  
Γ Rays ◽  
Minor Mergers

ABSTRACT Until recently, relativistic jets were ubiquitously found to be launched from giant elliptical galaxies. However, the detection by the Fermi-LAT of γ-ray emission from radio-loud narrow-line Seyfert 1 (RL-NLSy1) galaxies raised doubts on this relation. Here, we morphologically characterize a sample of 29 RL-NLSy1s (including 12 γ-emitters, γ-NLSy1s) in order to find clues on the conditions needed by active galactic nuclei (AGNs) to produce relativistic jets. We use deep near-infrared images from the Nordic Optical Telescope and the ESO VLT to analyse the surface brightness distribution of the galaxies in the sample. We detected 72 per cent of the hosts (24 per cent classified as γ-NLSy1s). Although we cannot rule out that some RL-NLSy1s are hosted by dispersion-supported systems, our findings strongly indicate that RL-NLSy1 hosts are preferentially disc galaxies. 52 per cent of the resolved hosts (77 per cent non-γ-emitters and 20 per cent γ-emitters) show bars with morphological properties (long and weak) consistent with models that promote gas inflows, which might trigger nuclear activity. The extremely red bulges of the γ-NLSy1s, and features that suggest minor mergers in 75 per cent of their hosts, might hint to the necessary conditions for γ-rays to be produced. Among the features that suggest mergers in our sample, we find six galaxies that show offset stellar bulges with respect to their AGNs. When we plot the nuclear versus the bulge magnitude, RL-NLSy1s locate in the low-luminosity end of flat spectrum radio quasars, suggesting a similar accretion mode between these two AGN types.

Hosts of jetted narrow-line Seyfert 1 galaxies in near-infrared

2019 ◽  
Vol 15 (S356) ◽  
pp. 172-172
Author(s):  
Emilia Järvelä
Keyword(s):  
Active Galactic Nuclei ◽  
Near Infrared ◽  
Small Sample Size ◽  
Galactic Nuclei ◽  
Small Sample ◽  
Host Galaxy ◽  
Narrow Line ◽  
Host Galaxies ◽  
Optical Telescope ◽  
Radio Observatory

AbstractHost galaxy morphology studies of jetted narrow-line Seyfert 1 galaxies (NLS1) are scarce. Although it seems that they are mostly hosted by late-type galaxies the results remain inconclusive, mostly due to the small sample size. Increasing the number of studied sources is crucial to achieve statistically significant results and to establish a preferred host type for jetted NLS1s. To this end we observed the host galaxies of nine NLS1s in near-infrared using NOTCam at the Nordic Optical Telescope. Seven of these sources are jetted based on the 37 GHz observations at Metsähovi Radio Observatory, Finland. To determine the morphological types of the hosts we performed photometric decomposition of the near-infrared images using GALFIT. Here we present the results of the host galaxy modelling, discuss the importance of this study to our understanding of the nature of the diverse NLS1 population, as well as its significance and implications for active galactic nuclei research in general.

scholarly journals Near-infrared morphologies of the host galaxies of narrow-line Seyfert 1 galaxies

2018 ◽  
Vol 619 ◽  
pp. A69 ◽  
Author(s):  
E. Järvelä ◽  
A. Lähteenmäki ◽  
M. Berton
Keyword(s):  
Near Infrared ◽  
Large Fraction ◽  
Galactic Nuclei ◽  
Host Galaxy ◽  
Narrow Line ◽  
Host Galaxies ◽  
Nuclear Activity ◽  
Nir Imaging ◽  
Heterogeneous Nature ◽  
Minor Mergers

We present J-band near-infrared (NIR) imaging of the host galaxies of nine narrow-line Seyfert 1 galaxies (NLS1). Based on high-frequency radio observations at 37 GHz, seven of them could host powerful jets that are most likely relativistic. Host galaxy morphology studies of NLS1 galaxies are scarce, but exceedingly important for understanding the seemingly heterogeneous nature of the NLS1 population as well as their evolution and place in the active galactic nuclei (AGN) scheme. Increasing the sample size is essential for achieving statistically significant results. We determine the morphological types of the host galaxies by performing photometric decomposition of NIR images using a 2D image decomposition algorithm GALFIT. We were able to sufficiently model five of the nine host galaxies. Based on the fitting parameters, mainly the Sérsic index, all five are disk-like galaxies. Sources with clearly distinguishable bulge components all have pseudo-bulges, and four out of five sources show a component resembling a bar. A surprisingly large fraction, three out of five, show signs of interaction or disturbed morphology. Our results suggest that spiral galaxies with pseudo-bulges are able to launch and maintain powerful jets. They also imply that interaction – mainly minor mergers – may have a role in initially triggering higher levels of nuclear activity in NLS1 galaxies. Furthermore, our results support the heterogeneous nature of the NLS1 class and indicate that this diversity is caused by different evolutionary stages, possibly due to mergers.

scholarly journals SDSS J211852.96−073227.5: The first non-local, interacting, late-type intermediate Seyfert galaxy with relativistic jets

2020 ◽  
Vol 636 ◽  
pp. L12 ◽  
Author(s):  
E. Järvelä ◽  
M. Berton ◽  
S. Ciroi ◽  
E. Congiu ◽  
A. Lähteenmäki ◽  
...  
Keyword(s):  
Near Infrared ◽  
Gamma Ray ◽  
Galactic Nuclei ◽  
Seyfert Galaxy ◽  
Late Type ◽  
Host Galaxies ◽  
Relativistic Jets ◽  
Galaxy Interactions ◽  
Non Local ◽  
First Time

It has been often suggested that a tangible relation exists between relativistic jets in active galactic nuclei (AGN) and the morphology of their host galaxies. In particular, relativistic jets may commonly be related to merging events. Here we present for the first time a detailed spectroscopic and morphological analysis of a Seyfert galaxy, SDSS J211852.96−073227.5, at z = 0.26. This source has previously been classified as a gamma-ray emitting narrow-line Seyfert 1 galaxy. We re-observed it with the 6.5 m Clay Telescope and these new, high-quality spectroscopic data have revealed that it is actually an intermediate-type Seyfert galaxy. Furthermore, the results of modelling the Ks-band near-infrared images obtained with the 6.5 m Baade Telescope indicate that the AGN is hosted by a late-type galaxy in an interacting system, strengthening the suggested connection between galaxy interactions and relativistic jets.

scholarly journals POWERFUL RELATIVISTIC JETS IN SPIRAL GALAXIES

2012 ◽  
Vol 08 ◽  
pp. 172-177 ◽  
Author(s):  
LUIGI FOSCHINI
Keyword(s):  
Active Galactic Nuclei ◽  
Spiral Galaxies ◽  
Galactic Nuclei ◽  
Radio Galaxies ◽  
High Energy ◽  
Narrow Line ◽  
Relativistic Jets ◽  
Accretion Rates ◽  
Γ Rays ◽  
Eddington Limit

The discovery of high-energy (E > 100 MeV) γ rays from Narrow-Line Seyfert 1 Galaxies (γ-NLS1s) has confirmed the presence of powerful relativistic jets in this class of active galactic nuclei (AGN). Although the jet emission is similar to that of blazars and radio galaxies, γ-NLS1s have some striking differences: relatively small masses (106-8 M⊙), high accretion rates (0.1-1 times the Eddington limit) and are generally hosted by spiral galaxies. It is now possible to study a rather unexplored range of mass and accretion rates of AGN with relativistic jets. Specifically, in this work I present some results obtained by comparing a sample of blazars and γ-NLS1s with another sample of Galactic binaries with relativistic jets (stellar mass black holes and neutron stars).

scholarly journals Gamma-ray emitting narrow-line Seyfert 1 galaxies. New discoveries and open questions

2013 ◽  
Vol 9 (S304) ◽  
pp. 140-143 ◽  
Author(s):  
F. D'Ammando ◽  
M. Orienti ◽  
J. Finke ◽  
J. Larsson ◽  
M. Giroletti
Keyword(s):  
Gamma Ray ◽  
Seyfert Galaxies ◽  
Radio Galaxies ◽  
Narrow Line ◽  
Relativistic Jets ◽  
Open Questions ◽  
Γ Rays ◽  
Γ Ray

AbstractThe discovery of γ-ray emission from 5 radio-loud narrow-line Seyfert 1 galaxies revealed the presence of a possible emerging third class of AGNs with relativistic jets, in addition to blazars and radio galaxies. The existence of relativistic jets also in this subclass of Seyfert galaxies opened an unexplored research space for our knowledge of the radio-loud AGNs. Here, we discuss the radio-to-γ-rays properties of the γ-ray emitting narrow-line Seyfert 1 galaxies, also in comparison with the blazar scenario.

scholarly journals Narrow-Line Seyfert 1 Galaxies With Absorbed Jets–Insights From Radio Spectral Index Maps

2021 ◽  
Vol 8 ◽  
Author(s):  
Emilia Järvelä ◽  
Marco Berton ◽  
Luca Crepaldi
Keyword(s):  
Radio Emission ◽  
Spectral Index ◽  
Large Scale ◽  
Wide Frequency Range ◽  
Narrow Line ◽  
Host Galaxies ◽  
Relativistic Jets ◽  
Additional Information ◽  
Spatially Resolved ◽  
Index Maps

Narrow-line Seyfert 1 (NLS1) galaxies are active galactic nuclei (AGN) believed to be in the early stages of their evolution. A fraction of them have been found to host relativistic jets. Due to the lack of large-scale diffuse radio emission they are believed to be experiencing one of their first activity cycles, and can offer us an opportunity to study the early evolution of more powerful AGN, such as radio galaxies and flat-spectrum radio quasars. Recently, a group of intriguing jetted NLS1s was discovered: based on high radio frequency data they host relativistic jets, but in the JVLA observations they all showed steep radio spectra at least up to 9.0 GHz, indicating very strong absorption at these frequencies. In this paper we study a subset of these sources in detail by employing spatially resolved radio spectral index maps at central frequencies of 1.6, 5.2, and 9.0 GHz. With spectral index maps we can disentangle the different radio emission components over the radio-emitting region, and get insights into the production mechanisms of radio emission. In addition, we study their host galaxies in relation to the radio emission to investigate if the host can provide us additional information regarding the origin of the radio emission, or the launching mechanism of the jets. It is fascinating how different the sources studied are, and certainly more, especially wide frequency-range, and high-resolution observations will be needed to understand their history and current properties, such as the reason behind the extraordinary radio spectra.

scholarly journals Multiwavelength morphological study of active galaxies

2019 ◽  
Vol 15 (S356) ◽  
pp. 295-298
Author(s):  
Betelehem Bilata-Woldeyes ◽  
Mirjana Pović ◽  
Zeleke Beyoro-Amado ◽  
Tilahun Getachew-Woreta ◽  
Shimeles Terefe
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Formation Rate ◽  
Stellar Mass ◽  
Active Galaxies ◽  
Morphological Properties ◽  
X Rays ◽  
Host Galaxies ◽  
X Ray ◽  
Public Data

AbstractStudying the morphology of a large sample of active galaxies at different wavelengths and comparing it with active galactic nuclei (AGN) properties, such as black hole mass (MBH) and Eddington ratio (λEdd), can help us in understanding better the connection between AGN and their host galaxies and the role of nuclear activity in galaxy formation and evolution. By using the BAT-SWIFT hard X-ray public data and by extracting those parameters measured for AGN and by using other public catalogues for parameters such as stellar mass (M*), star formation rate (SFR), bolometric luminosity (Lbol), etc., we studied the multiwavelength morphological properties of host galaxies of ultra-hard X-ray detected AGN and their correlation with other AGN properties. We found that ultra hard X-ray detected AGN can be hosted by all morphological types, but in larger fractions (42%) they seem to be hosted by spirals in optical, to be quiet in radio, and to have compact morphologies in X-rays. When comparing morphologies with other galaxy properties, we found that ultra hard X-ray detected AGN follow previously obtained relations. On the SFR vs. stellar mass diagram, we found that although the majority of sources are located below the main sequence (MS) of star formation (SF), still non-negligible number of sources, with diverse morphologies, is located on and/or above the MS, suggesting that AGN feedback might have more complex influence on the SF in galaxies than simply quenching it, as it was suggested in some of previous studies.

scholarly journals The radio-loud narrow-line Seyfert 1 galaxy 1H 0323+342 in a galaxy merger

2020 ◽  
Vol 496 (2) ◽  
pp. 1757-1765 ◽  
Author(s):  
Akihiro Doi ◽  
Motoki Kino ◽  
Nozomu Kawakatu ◽  
Kazuhiro Hada
Keyword(s):  
Black Holes ◽  
Near Infrared ◽  
Gamma Ray ◽  
Linear Structure ◽  
Seyfert Galaxies ◽  
Mass Function ◽  
High Mass ◽  
Host Galaxy ◽  
Supporting Evidence ◽  
Narrow Line

ABSTRACT The supermassive black holes (SMBHs) of narrow-line Seyfert 1 galaxies (NLS1s) are at the lower end of the mass function of active galactic nuclei (AGNs) and reside preferentially in late-type host galaxies with pseudobulges, which are thought to be formed by internal secular evolution. On the other hand, the population of radio-loud NLS1s presents a challenge for the relativistic jet paradigm, which states that powerful radio jets are associated exclusively with very high mass SMBHs in elliptical hosts, which are built up through galaxy mergers. We investigated distorted radio structures associated with the nearest gamma-ray-emitting, radio-loud NLS1, 1H 0323+342. This provides supporting evidence for the merger hypothesis based on past optical/near-infrared observations of its host galaxy. The anomalous radio morphology consists of two different structures: the inner curved structure of the currently active jet and an outer linear structure of low-brightness relics. Such coexistence might be indicative of the stage of an established black hole binary with precession before the black holes coalesce in the galaxy merger process. 1H 0323+342 and other radio-loud NLS1s under galaxy interactions may be extreme objects on the evolutionary path from radio-quiet NLS1s to normal Seyfert galaxies with larger SMBHs in classical bulges through mergers and merger-induced jet phases.

scholarly journals Optical and Near-Infrared Imaging of Ultra–Steep-Spectrum Radio Sources: The [ITAL]K[/ITAL]-[CLC][ITAL]z[/ITAL][/CLC] Diagram of Radio-selected and Optically Selected Galaxies

2002 ◽  
Vol 123 (2) ◽  
pp. 637-677 ◽  
Author(s):  
Carlos De Breuck ◽  
Wil van Breugel ◽  
S. A. Stanford ◽  
Huub Röttgering ◽  
George Miley ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Imaging ◽  
Radio Sources ◽  
Near Infrared Imaging ◽  
Spectrum Radio

scholarly journals Linking the central engine to the jet properties in radio loud AGN

2014 ◽  
Vol 10 (S313) ◽  
pp. 329-330
Author(s):  
A. Olguín-Iglesias ◽  
J. León-Tavares ◽  
V. Chavushyan ◽  
E. Valtaoja ◽  
C. Añorve ◽  
...  
Keyword(s):  
Black Hole ◽  
Host Galaxy ◽  
Base Line ◽  
Black Hole Mass ◽  
Host Galaxies ◽  
Optical Telescope ◽  
Central Engine ◽  
Early Results ◽  
Relativistic Jet ◽  
Line Array

AbstractWe explore the connection between the black hole mass and its relativistic jet for a sample of radio-loud AGN (z < 1), in which the relativistic jet parameters are well estimated by means of long term monitoring with the 14m Metsähovi millimeter wave telescope and the Very Long Base-line Array (VLBA). NIR host galaxy images taken with the NOTCam on the Nordic Optical Telescope (NOT) and retrieved from the 2MASS all-sky survey allowed us to perform a detailed surface brightness decomposition of the host galaxies in our sample and to estimate reliable black hole masses via their bulge luminosities. We present early results on the correlations between black hole mass and the relativistic jet parameters. Our preliminary results suggest that the more massive the black hole is, the faster and the more luminous jet it produces.

Sign in / Sign up

Export Citation Format

Share Document