J/A+A/658/A12 Origins of radio emission in NLS1s (Jarvela+, 2022)
Unravelling the origin of extended radio emission in narrow-line Seyfert 1
galaxies with the JVLA.
Jarvela E., Dahale R., Crepaldi L., Berton M., Congiu E., Antonucci R.
<Astron. Astrophys. 658, A12 (2022)>
=2022A&A...658A..12J 2022A&A...658A..12J (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio ; Radio continuum ; Active gal. nuclei ;
Galaxies, Seyfert
Keywords: galaxies: active - galaxies: ISM - galaxies: jets -
galaxies: star formation - radio continuum: galaxies
Abstract:
Narrow-line Seyfert 1 galaxies (NLS1s) are believed to be active
galactic nuclei (AGN) in the early stages of their evolution. Several
dozen of them have been found to host relativistic jets, whilst the
majority of NLS1s have not even been detected in radio, emphasising
the heterogeneity of the class in this band. In this paper, our aim is
to determine the predominant source of radio emission in a sample of
44 NLS1s, selected based on their extended kiloparsec-scale radio
morphologies at 5.2GHz. We accomplish this by analysing their
spatially resolved radio spectral index maps, centred at 5.2 GHz, as
the spectral index carries information about the production mechanisms
of the emission. In addition, we utilise several diagnostics based on
mid-infrared emission to estimate the star formation activity of their
host galaxies. These data are complemented by archival data to draw a
more complete picture of each source. We find an extraordinary
diversity among our sample. Approximately equal fractions (∼10-12
sources) of our sources can be identified as AGN-dominated, composite,
and host-dominated. Among the AGN-dominated sources are a few NLS1s
with very extended jets, reaching distances of tens of kiloparsecs
from the nucleus. One of these, J0814+5609, hosts the most extended
jets found in an NLS1 so far. We also identify five NLS1s that could
be classified as compact steep-spectrum sources. In addition, one
source shows a possible kiloparsec-scale relic that reaches well
outside the host galaxy as well as restarted nuclear activity, and one
could belong to the sub-class of NLS1s that host relativistic jets
that seem to be absorbed at lower radio frequencies (<10GHz). We
further conclude that, due to the variety seen in NLS1s, simple
proxies, such as the star formation diagnostics also employed in this
paper and the radio loudness parameter, are not ideal tools for
characterising NLS1s. We emphasise the necessity of examining NLS1s as
individuals instead of making assumptions based on their
classification. When these issues are properly taken into account,
NLS1s offer an exceptional environment for studying the interplay
between the host galaxy and several AGN-related phenomena, such as
jets and outflows.
Description:
The FITS files of the reduced radio maps, spectral index maps, and
tapered maps are provided.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 74 44 Basic data of the sample
list.dat 128 222 List of fits images
fits/* . 222 Individual fits images
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- SName Short name (JHHMM+DDMM)
12- 35 A24 --- Name Name (NED Alias)
37- 38 I2 h RAh Right ascension (J2000) from the JVLA radio map
40- 41 I2 min RAm Right ascension (J2000) from the JVLA radio map
43- 47 F5.2 s RAs Right ascension (J2000) from the JVLA radio map
49 A1 --- DE- Declination sign (J2000) from the JVLA radio map
50- 51 I2 deg DEd Declination (J2000) from the JVLA radio map
53- 54 I2 arcmin DEm Declination (J2000) from the JVLA radio map
56- 60 F5.2 arcsec DEs Declination (J2000) from the JVLA radio map
62- 66 F5.3 --- z Redshift
68- 72 F5.3 kpc/arcsec Scale Scale
74 A1 --- Morph [I/E] Radio morphology type
(I = intermediate, E = extended)
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Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- SName Short name (JHHMM+DDMM)
12- 20 F9.5 deg RAdeg Right Ascension of center (J2000)
21- 29 F9.5 deg DEdeg Declination of center (J2000)
31- 34 I4 --- Nx Number of pixels along X-axis
36- 39 I4 --- Ny Number of pixels along Y-axis
41- 66 A26 "datime" Obs.date Observation date
68- 72 I5 Kibyte size Size of FITS file
74- 92 A19 --- FileName Name of FITS file, in subdirectory fits
94-128 A35 --- Title Title of the FITS file
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Acknowledgements:
Emilia Jarvela, astrojarvela(at)gmail.com
References:
Berton et al., 2018A&A...614A..87B 2018A&A...614A..87B
(End) Patricia Vannier [CDS] 06-Jan-2022