J/A+A/710/A222 HE 1237-2252 spectra (Markowitz+, 2026)
A changing-look Seyfert discovered by eROSITA reveals a two-component
broad-line region.
Markowitz A., Krumpe M., Homan D., Czerny B., Gromazdki M., Winkler H.,
Wilms J., Haemmerich S., Lamer G., Saha T., Buckley D.A.H., Schramm M.,
Reichart D.E., Salvato M., Baldini P.
<Astron. Astrophys. 710, A222 (2026)>
=2026A&A...710A.222M 2026A&A...710A.222M (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei; Galaxies, Seyfert; Galaxies, spectra;
Spectra, optical ; X-ray sources
Keywords: galaxies: active - galaxies: individual objects: HE 1237-2252 -
galaxies: Seyfert - X-rays: galaxies
Abstract:
Extreme sudden changes in the flow of accreting gas onto supermassive
black holes manifest themselves via large-amplitude
multiband continuum variability, as well as changes to broad Balmer
emission profiles, driving changing-look active galactic nuclei (AGN).
X-ray flux monitoring with Spectrum Roentgen Gamma (SRG)/eROSITA
revealed that in the Seyfert AGN HE 1237-2252 the soft X-ray flux
dipped abruptly, by a factor of 17 within 18 months. We initiated a
follow-up campaign that caught the luminosity recovery after the dip,
and enabled us to study how the various accretion components,
including the broad-line region (BLR) and X-ray-emitting coronae,
responded during this flux recovery.
Our campaign included multiband photometry, X-ray spectroscopy, and
optical spectroscopy. We tracked as the accretion rate relative to
Eddington increased by a factor of 7 in 3 years.
Based on broad Hβ variability, HE 1237-2252 was subtype 1.0-1.2
in 2002, transitioned to subtype 1.8 by the time of the luminosity
dip, and then transitioned back to subtype 1.0 within 3 months as
luminosity recovered. Both transitions saw broad Hβ integrated
line flux change by factors of 4-6. The broad Balmer profile is
decomposed into a broad Gaussian consistent with virialized gas at
27±3 lt-dy, plus a double-peaked profile, consistent with a diskline
structure at ≳5 lt-dy. The diskline component's relative
contribution to the total profile increases as continuum flux rises.
The lack of significant obscuration in the X-ray spectra, as well as
the IR continuum dip, point to an intrinsic pause in the accretion
rate as opposed to variable line-of-sight obscuration. Candidates for
the underlying mechanisms include propagating cold and warm fronts in
the accretion disk. The increased prominence of the diskline BLR
component's emission could be due to evolution in the physical
extent of the X-ray corona, and in the fraction of >13.6eV photons
intercepted by the diskline, as the accretion rate increases.
Description:
The 21 optical spectra used in our spectral modeling. Spectra have
been shifted to the rest frame. They are not corrected for Galactic
extinction. Spectra have been grey-scaled by matching integrated
[OIII] flux to that of a reference spectrum (spectrum no. 3)
Objects:
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RA (2000) DE Designation(s)
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12 40 28.32 -23 09 26.6 HE 1237-2252 = 1RXS J124027.2-230925
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 57 23 List of spectra
sp/* . 23 Individual spectra
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- FileName Name of the spectrum file in subdirectory sp
14- 57 A44 --- Title Tile of the file
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Byte-by-byte Description of file (#): sp/*
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Bytes Format Units Label Explanations
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1- 12 F12.6 0.1nm lambda Rest-frame wavelength (in Å units)
17- 28 F12.6 10-18W/m2/nm FluxDens Flux density
(in 10-16erg/cm2/s/Å units)
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Acknowledgements:
Alex Markowitz, almarkowitz(at)camk.edu.pl,
CAMK-PAN, Warsaw, Poland
License: CC-BY-4.0
(End) Alex Markowitz [CAMK-PAN, Warsaw], Patricia Vannier [CDS] 13-May-2026