J/ApJ/937/7 Low-mass active galaxies from GAMA DR4 (Salehirad+, 2022)
Hundreds of low-mass active galaxies in the Galaxy And Mass Assembly (GAMA)
survey.
Salehirad S., Reines A.E., Molina M.
<Astrophys. J., 937, 7 (2022)>
=2022ApJ...937....7S 2022ApJ...937....7S
ADC_Keywords: Active gal. nuclei; Galaxies, spectra; Optical; Redshifts
Keywords: Active galactic nuclei ; Black holes ; Astrophysical black holes ;
Active galaxies ; Low-luminosity active galactic nuclei
Abstract:
We present an entirely new sample of 388 low-mass galaxies
(M*≤1010M☉) that have spectroscopic signatures indicating
the presence of massive black holes (BHs) in the form of active
galactic nuclei (AGNs) or tidal disruption events. Of these, 70 have
stellar masses in the dwarf galaxy regime with
108≲M*/M☉≲109.5. We identify the active galaxies by
analyzing optical spectra of a parent sample of ∼23000 low-mass
emission-line galaxies in the Galaxy and Mass Assembly (GAMA) Survey
Data Release 4, and employing four different diagnostics based on
narrow emission-line ratios and the detection of high-ionization
coronal lines. We find that 47 of the 388 low-mass active galaxies
exhibit broad Hα in their spectra, corresponding to virial BH
masses in the range MBH∼105.0-7.7M☉ with a median BH mass of
<MBH≳106.2M☉. Our sample extends to higher redshifts
(z≤0.3; =0.13) than previous samples of AGNs in low-mass/dwarf
galaxies based on Sloan Digital Sky Survey spectroscopy, which can be
attributed to the spectroscopic limit of GAMA being ∼2mag deeper.
Moreover, our multi-diagnostic approach has revealed low-mass active
galaxies spanning a wide range of properties, from blue star-forming
dwarfs to luminous "miniquasars" powered by low-mass BHs. As such,
this work has implications for BH seeding and AGN feedback at low
masses.
Description:
The GAMA Survey includes optical spectroscopy taken with the AAOmega
multi-object spectrograph on the 3.9m Angelo-Australian Telescope (AAT).
In this work, we utilize spectra and stellar masses released in GAMA
DR4 covering three equatorial 60deg2 regions (G09, G12 and G15) and
two southern ∼50deg2 regions (G02 and G23).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 81 388 AGNs in low-mass galaxies
table2.dat 99 388 Emission-line fluxes
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See also:
II/329 : VIKING catalogue data release 1 (Edge+, 2013)
II/343 : VIKING catalogue data release 2 (Edge+, 2016)
J/A+AS/136/35 : WR galaxies and HII regions catalog (Schaerer+ 1999)
J/ApJ/670/92 : New sample of low-mass black holes in AGN (Greene+, 2007)
J/MNRAS/398/1165 : AGN in nearby galaxies (Goulding+, 2009)
J/ApJ/755/167 : Low-mass black holes in SDSS Sy1 galaxies (Dong+, 2012)
J/MNRAS/421/1043 : Emission-line galaxies from SDSS DR7 (Shirazi+, 2012)
J/ApJ/775/116 : z<0.06 active black hole gal. from SDSS-DR8 (Reines+, 2013)
J/MNRAS/452/2087 : Galaxy And Mass Assembly (GAMA): DR2 (Liske+, 2015)
J/ApJ/813/82 : z<0.06 broad-line AGN emission-line measures (Reines+, 2015)
J/MNRAS/454/3722 : AGN in nearby low-mass galaxies (Sartori+, 2015)
J/MNRAS/474/3875 : Galaxy And Mass Assembly (GAMA): DR3 (Baldry+, 2018)
J/ApJ/922/155 : [FeX]λ6374 em. in SDSS dwarf galaxies (Molina+, 2021)
http://www.gama-survey.org/ : Galaxy And Mass Assembly (GAMA) homepage
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 I7 --- CataId [7392/5374676] Unique ID of the GAMA object
(1)
9- 17 F9.5 deg RAdeg [30.26/351] Spectrum Right Ascension in
decimal degrees (J2000) (1)
19- 27 F9.5 deg DEdeg [-35/3] Spectrum Declination in decimal
degrees (J2000) (1)
29- 35 F7.5 --- z [0.013/0.3] Spectroscopic redshift (1)
37- 41 F5.2 [Msun] logM [7.9/10] Log stellar mass (1)
43- 48 F6.2 mag gMag [-22.24/-12.45] Absolute g-band magnitude (1)
50- 53 F4.2 mag g-r [0.06/1.5] The (g-r) color index (1)
55- 59 A5 --- NIILoc Galaxy location in [NII]/HA diagram (2)
61- 63 A3 --- HeIILoc Galaxy location in HeII/HB diagram (2) (3)
65- 72 A8 --- FeXDet A [FeX] detection? (3)
74- 81 A8 --- NeVDet A [NeV] detection? (3)
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Note (1): All values are from GAMA and assume h=0.7.
Note (2): The classification of the galaxies in the [OIII]/Hβ vs.
[NII]/Hα and HeII/Hβ vs. [NII]/Hα
diagnostic diagrams.
Note (3): Blank if no line is detected.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 I7 --- CataId [7392/5374676] Unique ID of the GAMA
object
9- 11 I3 10-17mW/m2 NeV3426 [0/247] The [NeV]3426 emission line
flux (1)
13 I1 10-17mW/m2 e_NeV3426 [0/9] Uncertainty in NeV3426 (1)
15- 17 I3 10-17mW/m2 HeII4686 [0/193] HeII 4686 emission line flux (1)
19- 20 I2 10-17mW/m2 e_HeII4686 [0/31] Uncertainty in HeII4686 (1)
22- 25 I4 10-17mW/m2 Hbeta-n [3/1427] Narrow Hbeta emission line flux
(1)
27- 28 I2 10-17mW/m2 e_Hbeta-n [1/27] Uncertainty in Hbeta-n (1)
30- 33 I4 10-17mW/m2 Hbeta-b [0/1239] Broad Hbeta emission line flux
(1)
35- 36 I2 10-17mW/m2 e_Hbeta-b [0/34] Uncertainty in Hbeta-b (1)
38- 41 I4 10-17mW/m2 OIII5007 [8/4528] The [OIII]5007 emission line
flux (1)
43- 45 I3 10-17mW/m2 e_OIII5007 [1/218] Uncertainty in OIII5007 (1)
47- 49 I3 10-17mW/m2 OI6300 [0/165] The [OI]6300 emission line
flux (1)
51- 52 I2 10-17mW/m2 e_OI6300 [0/18] Uncertainty in OI6300 (1)
54- 56 I3 10-17mW/m2 FeX6374 [0/115] The [FeX]6374 emission line
flux (1)
58- 59 I2 10-17mW/m2 e_FeX6374 [0/14] Uncertainty in FeX6374 (1)
61- 64 I4 10-17mW/m2 Halpha-n [15/5487] Narrow Halpha emission line
flux (1)
66- 67 I2 10-17mW/m2 e_Halpha-n [1/60] Uncertainty in Halpha-n (1)
69- 72 I4 10-17mW/m2 Halpha-b [0/4349] Broad Halpha emission line flux
(1)
74- 76 I3 10-17mW/m2 e_Halpha-b [0/110] Uncertainty in Halpha-b (1)
78- 81 I4 10-17mW/m2 NII6583 [7/1673] The [NII]6583Å emission line
flux (1)
83- 84 I2 10-17mW/m2 e_NII6583 [1/45] Uncertainty in NII6583 (1)
86- 88 I3 10-17mW/m2 SII6716 [0/944] The [SII]6716 emission line
flux (1)
90- 91 I2 10-17mW/m2 e_SII6716 [0/25] Uncertainty in SII6716 (1)
93- 95 I3 10-17mW/m2 SII6731 [0/730] The [SII]6731 emission line
flux (1)
97- 99 I3 10-17mW/m2 e_SII6731 [0/25] Uncertainty in SII6731 (1)
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Note (1): The fluxes are in units of erg/s/cm^2. Here a flux value of 0
indicates no line detection. No extinction correction is applied.
In case of broad Halpha and Hbeta detections, their respective
narrow components are being used.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 07-Aug-2024