J/A+A/681/A97 Massive black holes in low-mass galaxies (Arcodia+, 2024)
O Corona, where art thou? eROSITA's view of UV-optical-IR variability-selected
massive black holes in low-mass galaxies.
Arcodia R., Merloni A., Comparat J., Dwelly T., Seppi R., Zhang Y.,
Buchner J., Georgakakis A., Haberl F., Igo Z., Kyritsis E., Liu T.,
Nandra K., Ni Q., Ponti G., Salvato M., Ward C., Wolf J., Zezas A.
<Astron. Astrophys., 681, A97 (2024)>
=2024A&A...681A..97A 2024A&A...681A..97A (SIMBAD/NED BibCode)
ADC_Keywords: X-ray sources ; Galaxies ; Black holes
Keywords: accretion, accretion disks - black hole physics - galaxies: active -
galaxies: dwarf - X-rays: galaxies
Abstract:
Finding massive black holes (MBHs, MBH∼104-107M☉) in the
nuclei of low-mass galaxies (M*≤1010M☉) is crucial to
constrain seeding and growth of black holes over cosmic time, but it
is particularly challenging due to their low accretion luminosities.
Variability selection via long-term photometric ultraviolet, optical,
or infrared (UVOIR) light curves has proved effective and identifies
lower-Eddington ratios compared to broad and narrow optical spectral
lines searches. In the inefficient accretion regime, X-ray and radio
searches are effective, but they have been limited to small samples.
Therefore, differences between selection techniques have remained
uncertain. Here, we present the first large systematic investigation
of the X-ray properties of a sample of known MBH candidates in dwarf
galaxies. We extracted X-ray photometry and spectra of a sample of
∼200 UVOIR variability-selected MBHs and significantly detected 17 of
them in the deepest available SRG/eROSITA image, of which four are
newly discovered X-ray sources and two are new secure MBHs. This
implies that tens to hundreds of LSST MBHs will have SRG/eROSITA
counterparts, depending on the seeding model adopted. Surprisingly,
the stacked X-ray images of the many non-detected MBHs are
incompatible with standard disk-corona relations, typical of active
galactic nuclei, inferred from both the optical and radio fluxes. They
are instead compatible with the X-ray emission predicted for normal
galaxies. After careful consideration of potential biases, we
identified that this X-ray weakness needs a physical origin. A
possibility is that a canonical X-ray corona might be lacking in the
majority of this population of UVOIR-variability selected low-mass
galaxies or that unusual accretion modes and spectral energy
distributions are in place for MBHs in dwarf galaxies. This result
reveals the potential for severe biases in occupation fractions
derived from data from only one waveband combined with SEDs and
scaling relations of more massive black holes and galaxies.
Description:
We presented the first large systematic investigation of the X-ray
properties of a sample of known MBH candidates, which has the
advantage of providing a sample with occupation and active fraction of
one. We focused on MBHs selected through UVOIR variability. We have
extracted X-ray photometry and spectra of a sample of 214 (208) UVOIR
variability-selected MBHs from the eRASS1 (eRASS:4) image and
significantly detect 11 (17) of them (table B1).
Out of the 17 detected galaxies from the deeper eRASS:4 image, 4 are
newly-discovered X-ray sources (Table B2), two of which are securely
X-ray counterparts of the variable MBHs, whilst the other two remain
ambiguous.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 144 216 Input MBH candidates from optical/IR/UV
variability and related eROSITA information
from aperture photometry and spectroscopy
tableb2.dat 81 17 eRASS:4 detections matched with XMM-Newton,
Chandra, ROSAT and Swift-XRT
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See also:
J/ApJ/896/10 : NSA low-mass galaxies with long-term PTF observations
(Baldassare+, 2020)
J/ApJ/894/24 : Optical variability of AGN from the HSC SSP survey
(Kimura+, 2020)
Byte-by-byte Description of file: tableb1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 F11.7 deg RAdeg Input right ascension (J2000)
14- 24 F11.7 deg DEdeg Input declination (J2000)
26- 31 F6.4 --- z Redshift
33- 37 F5.2 Msun M* Stellar mass
39- 43 A5 --- Ref Reference for input coordinates, redshift
and stellar mass (1)
45- 53 E9.3 --- PB1 eRASS1 no-source probability PB (Eq. 1) (2)
56 A1 --- l_LX1 Limit flag on LX1
57- 61 F5.2 [10-7W] LX1 ?=- eRASS1 median logarithmic X-ray luminosity
in the rest-frame 0.2-2.0keV range for
detected source or 1σ upper limit for
non detected source (3)
63- 67 F5.2 [10-7W] LX1-16 ? eRASS1 L0.2-2.0keV 16th percentile
for detected source
69- 73 F5.2 [10-7W] LX1-84 ? eRASS1 L0.2-2.0keV 84th percentile
for detected source
76- 80 F5.2 [10-7W] LX1-1 ? eRASS1 L0.2-2.0keV 1st percentile
for detected source
82- 86 F5.2 [10-7W] LX1-99 ? eRASS1 L0.2-2.0keV 99th percentile
for detected source
89- 93 F5.2 [10-7W] LX1-3s ? eRASS1 logarithmic X-ray luminosity in the
rest-frame 0.2-2.0keV range 3σ upper
limit for non detected source
96-104 E9.3 --- PB4 eRASS4 no-source probability PB (Eq. 1) (2)
107 A1 --- l_LX4 Limit flag on LX4
108-112 F5.2 [10-7W] LX4 ?=- eRASS4 median logarithmic X-ray luminosity
in the rest-frame 0.2-2.0keV range for
detected source or 1σ upper limit
for non detected source (3)
114-118 F5.2 [10-7W] LX4-16 ? eRASS4 L0.2-2.0keV 16th percentile
for detected source
120-124 F5.2 [10-7W] LX4-84 ? eRASS4 L0.2-2.0keV 84th percentile
for detected source
127-131 F5.2 [10-7W] LX4-1 ? eRASS4 L0.2-2.0keV 1st percentile
for detected source
133-137 F5.2 [10-7W] LX4-99 ? eRASS4 L0.2-2.0keV 99th percentile
for detected source
140-144 F5.2 [10-7W] LX2-3s ? eRASS2 logarithmic X-ray luminosity in the
rest-frame 0.2-2.0keV range 3σ upper
limit for non detected source
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Note (1): Reference for as follows:
Ba18 = Baldassare et al. (2018ApJ...868..152B 2018ApJ...868..152B)
Ba20 = Baldassare et al. (2020ApJ...896...10B 2020ApJ...896...10B, Cat. J/ApJ/896/10)
B22 = Burke et al. (2022MNRAS.516.2736B 2022MNRAS.516.2736B)
W22Z = ZTF-selected sources from Ward et al. (2022ApJ...936..104W 2022ApJ...936..104W)
Ki20 = Kimura et al. (2020ApJ...894...24K 2020ApJ...894...24K, Cat. J/ApJ/894/24)
Sh22 = Shin et al. (2022AJ....163...73S 2022AJ....163...73S)
W22W = Wise-selected sources from Ward et al. (2022ApJ...936..104W 2022ApJ...936..104W)
S20 = Secrest & Satyapal (2020ApJ...900...56S 2020ApJ...900...56S)
Ha23 = Harish et al. (2023ApJ...945..157H 2023ApJ...945..157H)
Was22 = Wasleske et al. (2022ApJ...933...37W 2022ApJ...933...37W)
Note (2): Sources are considered detected at PB<0.0003.
Note (3): Sources which were masked out (see Sect. 3) are shown with dashes.
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Byte-by-byte Description of file: tableb2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 F11.7 deg RAdeg Right ascension (J2000)
13- 22 F10.6 deg DEdeg Declination (J2000)
24- 28 F5.2 [10-7W] LX4 eRASS4 median logarithmic X-ray luminosity
in the rest-frame 0.2-2.0keV range
30- 34 F5.2 [10-7W] LX4-16 eRASS4 L0.2-2.0keV 16th percentile
36- 40 F5.2 [10-7W] LX4-84 eRASS4 L0.2-2.0keV 84th percentile
43- 47 F5.2 [10-7W] LX4-1 eRASS4 L0.2-2.0keV 1st percentile
49- 53 F5.2 [10-7W] LX4-99 eRASS4 L0.2-2.0keV 99th percentile
55 A1 --- Note [*] * for sources with no previous
X-ray detections
57 A1 --- XMM [Y-] Match with XMM source ?
59 A1 --- Chandra [Y-] Match with Chandra source ?
61 A1 --- ROSAT [Y-] Match with ROSAT source ?
63 A1 --- Swift [Y-] Match with Swift source ?
65- 81 A17 --- Com Comments
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 24-Apr-2024