J/A+A/676/A102 Radio properties of the LOFAR lmETG sample (Capetti+, 2023)
The LOFAR view of massive early-type galaxies:
Transition from radio AGN to host emission.
Capetti A., Brienza M.
<Astron. Astrophys., 676, A102 (2023)>
=2023A&A...676A.102C 2023A&A...676A.102C (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio ; Active gal. nuclei
Keywords: galaxies: active - galaxies: jets
Abstract:
We extend the study of the radio emission in early-type galaxies
(ETGs) in the nearby Universe (recession velocity <7500km/s) as seen
by the 150MHz Low-Frequency ARray (LOFAR) observations and extend the
sample from giant ETGs to massive (∼6x1010-3x1011M☉) ETGs
(mETGS) with -25<MK←23.5. Images from the second data release of
the LOFAR Two-metre Sky Survey were available for 432 mETGs, 48% of
which are detected above a typical luminosity of ∼3x1020W/Hz. Most
(85%) of the detected sources are compact, with sizes ∼4kpc. The radio
emission of 31 mETGs is extended on scales ranging from 2 to 180kpc
(median 12kpc). In several cases, it is aligned with the host galaxy.
We set a limit of ≲1% to the fraction of remnant or restarted
objects, which is ≲16% of the extended sources. We found that the
properties of the radio sources are connected with the stellar mass of
the ETGs (the median radio power, the fraction of extended radio
sources, and the link with the large-scale environment). However,
these results only describe statistical trends because the radio
properties of sources of similar stellar mass and environment show a
large spread of radio properties. These trends break at the lowest
host luminosities (MK>-24.5). This effect is strengthened by the
analysis of even less massive ETGs, with -23.5<MK←21.5. This
suggests that at a mass of ∼2x1011M☉, a general transition
occurs from radio emission produced from radio-loud active galactic
nuclei (AGN) to processes related to the host galaxy and (or) radio
quiet AGN. At this luminosity, a transition in the stellar surface
brightness profile also occurs from Sersic galaxies to those with a
depleted stellar core, the so-called core galaxies. This finding is in
line with previous results that indicated that only core galaxies host
radio-loud AGN.
Description:
The luminosity distribution at 150MHz of the 55 detected lmETGs covers
a wide range in power, from ∼3x1019W/Hz to ∼1023W/Hz. One hundred
and three lmETGs are not detected by the LOFAR observations, and the
median limit to their radio luminosities is 2.5x1020W/H. The
fraction of detected lmETGs is smaller than that measured in the
samples of more massive ETGs. It is 35%, 48%, and 78% for the lmETGs,
mETG, and gETGs, respectively. We list the main properties of the
lmETG sample in Table D.1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tabled1.dat 79 432 Radio properties of the lmETG sample
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See also:
J/A+A/598/A104 : LOFAR Two-metre Sky Survey (Shimwell+, 2017)
J/A+A/622/A1 : LOFAR Two-metre Sky Survey DR1 source catalog (Shimwell+ 2019)
J/A+A/648/A2 : LOFAR Two-metre Sky Survey Deep Fields DR1 (Sabater+, 2021)
J/A+A/648/A3 : LOFAR Two-metre Sky Survey Deep Fields DR1 (Kondapally+, 2021)
J/A+A/648/A104 : LOFAR LBA Sky Survey. I. (de Gasperin+, 2021)
J/A+A/659/A1 : LOFAR Two-metre Sky Survey (LoTSS) DR2 (Shimwell+, 2022)
J/A+A/673/A165 : LOFAR LBA Sky Survey First Release (de Gasperin+, 2023)
J/A+A/674/A119 : LoTTS Deep Fields ELAIS-N1 (Snidaric+, 2023)
J/A+A/674/A189 : Matching LOFAR sources across radio bands (Boehme+, 2023)
Byte-by-byte Description of file: tabled1.dat
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Bytes Format Units Label Explanations
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1- 24 A24 --- Name Name
26- 33 F8.4 deg RAdeg Right ascension (J2000)
35- 41 F7.4 deg DEdeg Declination (J2000)
43- 46 I4 km/s v recession velocity
48- 53 F6.2 mag KMAG K-band absolute magnitude
55- 58 F4.2 mJy/beam rms r.m.s. noise of the LOFAR image
60 A1 --- l_F150 Limit flag on F150
61- 66 F6.1 mJy F150 Flux density at 150MHz from LOFAR
68- 70 F3.1 mJy e_F150 ? Flux density at 150MHz from LOFAR error
72 A1 --- l_L150 Limit flag on L150
73- 77 F5.2 W/Hz L150 Luminosity at 150NHz from LOFAR
79 A1 --- n_L150 [EP] E for extended,
P for unresolved or marginally resolved
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 08-Apr-2024