J/A+A/630/A83 4.85 and 10.45GHz fluxes of SDSS-FIRST sources (Zajacek+, 2019)
Radio spectral index distribution of SDSS-FIRST sources across optical
diagnostic diagrams.
Zajacek M., Busch G., M.Valencia-S., Eckart A., Britzen S., Fuhrmann L.,
Schneeloch J., Fazeli N., Harrington K.C., Zensus J.A.
<Astron. Astrophys. 630, A83 (2019)>
=2019A&A...630A..83Z 2019A&A...630A..83Z (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Radio sources
Keywords: radio continuum: galaxies - methods: observational -
techniques: spectroscopic - galaxies: active
Abstract:
A detailed understanding of how the activity of a galactic nucleus
regulates the growth of its host is still missing. To understand the
activity and the types of accretion of supermassive black holes in
different hosts, it is essential to study radio-optical properties of
a large sample of extragalactic sources. In particular, we aim at
studying the radio spectral index trends across the optical emission
line diagnostic diagrams to search for potential (anti)correlations.
To this goal, we combine flux densities from the radio FIRST survey at
1.4GHz (with the flux density range 10mJy≤F1.4≤1000mJy
for 209 SDSS sources at intermediate redshift (0.04≤z≤0.4) with the
Effelsberg radiotelescope measurements at 4.85GHz and 10.45GHz. The
information about the optical emission-line ratios is obtained from
the SDSS-DR7 catalogue. Using the Effelsberg data, we were able to
infer the two-point radio spectral index distributions for
star-forming galaxies, composite galaxies (with a combined
contribution to the line emission from the star-formation and AGN
activity), Seyferts, and low ionization narrow emission region (LINER)
galaxies. While studying the distribution of steep, flat, and inverted
sources across optical diagnostic diagrams, we found three distinct
classes of radio emitters for our sample: (i) sources with steep radio
index, high ionization ratio and high radio loudness, (ii) sources
with flat radio index, lower ionization ratio and intermediate radio
loudness, (iii) sources with inverted radio index, low ionization
ratio and low radio loudness. The classes (i), (ii), (iii) cluster
mainly along the transition from Seyfert to LINER sources in the BPT
diagram. We interpret these groups as a result of the recurrent
nuclear-jet activity.
Description:
Radio-continuum flux densities at 4.85GHz and 10.45GHz for 90
galaxies in the redshift range 0.04<z<0.4 are presented. The
observations were performed with the Effelsberg 100-m telescope using
the cross-scan technique between 2014-2015. 1-sigma uncertainties of
the measurements are included. The sources are a part of FIRST and
SDSS surveys, with the flux densities at 1.4GHz between 10 and
100mJy.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 57 90 New measurements at 4.85 and 10.45GHz
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 5 F5.3 --- z Source redshift
7- 8 I2 h RAh Right ascension (J2000.0)
10- 11 I2 min RAm Right ascension (J2000.0)
13- 16 F4.1 s RAs Right ascension (J2000.0)
18 A1 --- DE- [±] declination sign
19- 20 I2 deg DEd Declination (J2000.0)
22- 23 I2 arcmin DEm Declination (J2000.0)
25- 29 F5.2 arcsec DEs Declination (J2000.0)
31- 35 F5.1 mJy F4.85 Flux density at 4.85GHz
37- 41 F5.1 mJy e_F4.85 1-sigma error at 4.85GHz
43- 47 F5.1 mJy F10.45 Flux density at 10.45GHz
49- 52 F4.1 mJy e_F10.45 1-sigma error at 10.45GHz
54- 57 A4 --- Type Galaxy spectral type (1)
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Note (1): Spectral type is determined based on the galaxy position in the
narrow-line optical diagnostic diagram ([NII]-based BPT diagram).
We distinguish four spectral types as follows:
SF = star-forming galaxies
COMP = composites
SEY = Seyferts
LIN = LINERs
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Acknowledgements:
Michal Zajacek, zajacek(at)cft.edu.pl
(End) Michal Zajacek [CFT PAN, Poland], Patricia Vannier [CDS] 20-Aug-2019