J/A+A/711/A184 Properties of type 2 AGNs (Yoon+, 2026)
Only obscured yet luminous active galactic nuclei are closely associated with
galaxy mergers:
Direct observational evidence from type 2 active galactic nuclei.
Yoon Y., Kim Y., Kim D., Chun K., Byun W.
<Astron. Astrophys. 711, A184 (2026)>
=2026A&A...711A.184Y 2026A&A...711A.184Y (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Redshifts ; Optical
Keywords: galaxies: active - galaxies: interaction - quasars: general -
quasars: supermassive black holes
Abstract:
To establish a more comprehensive understanding of the connection
between galaxy mergers and active galactic nuclei (AGNs), it is
essential to disentangle the contributions of intrinsic AGN luminosity
and dust extinction to the merger-AGN connection. Since tidal
features identified in deep images serve as direct evidence of recent
mergers, we study the fraction of AGN hosts with tidal features (fT)
for a large sample of 748 type 2 AGNs at z<0.063. Specifically, we
examine fT as a function of E(B-V), derived from the Balmer
decrement, and the internal-extinction-corrected luminosity of the
[OIII] λ5007 emission line (L[OIII]), which is a proxy for
bolometric AGN luminosity. Our main finding is that fT is
significantly higher only for AGNs that are simultaneously luminous
and heavily dust-obscured. Specifically, AGNs with log L[OIII]≳41.5
and E(B-V)≳0.7 exhibit a high fT of ∼0.7. In contrast, AGNs with
either low luminosity (log L_[OIII]≲41.0) or low dust obscuration
(E(B-V)≲0.3) show a low fT of ≲0.2. This trend suggests that
galaxy mergers preferentially trigger AGNs that are simultaneously
luminous and dust-obscured, whereas AGNs that are either luminous but
unobscured or dust-obscured but less luminous are not strongly
associated with merger-driven triggering. Based on several
assumptions, our result can also be interpreted, despite certain
caveats, within the framework of a merger-initiated evolution model
for AGNs, suggesting that AGNs that are both obscured and luminous are
temporally closer to merger events than those with lower luminosity
and less dust obscuration.
Description:
We took 748 type 2 AGNs at z<0.063 from the Max Planck Institute for
Astrophysics-Johns Hopkins University (MPA-JHU) catalog available at
https://www.sdss.org/dr17/spectro/galaxy_mpajhu/. Including the
logarithmic stellar mass estimates from the original catalog, we
present our estimates of the type 2 AGNs, such as E(B-V) derived from
the Balmer decrement, logarithmic luminosity of the [OIII]
λ5007 emission line corrected for internal extinction, and
presence of tidal features.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 65 748 Properties of type 2 AGNs
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- ObjID Object ID in SDSS
21- 29 F9.5 deg RAdeg Right ascension (J2000) (RA)
31- 39 F9.5 deg DEdeg Declination (J2000) (DEC)
41- 47 F7.5 --- z Redshift
49- 52 F4.2 mag E(B-V) Intrinsic color excess derived from
Balmer decrement
54- 58 F5.2 [10-7W] logLOIII Logarithmic luminosity of [OIII]
λ5007 emission line (in erg/s)
60- 63 F4.1 [Msun] logMstar Logarithmic stellar mass
65 A1 --- TidalFeature [Y/N] Presence of tidal features in the
host galaxy; Y = present, N = absent
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Acknowledgements:
Yongjung Kim, yongjungkim(at)sejong.ac.kr
License: CC-BY-4.0
(End) Patricia Vannier [CDS] 05-May-2026