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Title: A Catalog Sample of Low-mass Galaxies Observed in X-Rays with Central Candidate Black Holes

Abstract

We present a sample of X-ray-selected candidate black holes in 51 low-mass galaxies with z ≤ 0.055 and masses up to 10{sup 10} M {sub ⊙} obtained by cross-correlating the NASA-SLOAN Atlas with the 3XMM catalog. We have also searched in the available catalogs for radio counterparts of the black hole candidates and find that 19 of the previously selected sources also have a radio counterpart. Our results show that about 37% of the galaxies of our sample host an X-ray source (associated with a radio counterpart) spatially coincident with the galaxy center, in agreement with other recent works. For these nuclear sources, the X-ray/radio fundamental plane relation allows one to estimate the mass of the (central) candidate black holes, which are in the range of 10{sup 4}–2 × 10{sup 8} M {sub ⊙} (with a median value of ≃3 × 10{sup 7} M {sub ⊙} and eight candidates having masses below 10{sup 7} M {sub ⊙}). This result, while suggesting that X-ray emitting black holes in low-mass galaxies may have had a key role in the evolution of such systems, makes it even more urgent to explain how such massive objects formed in galaxies. Of course, dedicated follow-up observationsmore » both in the X-ray and radio bands, as well as in the optical, are necessary in order to confirm our results.« less

Authors:
; ; ; ;  [1]
  1. Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via per Arnesano, CP 193, I-73100, Lecce (Italy)
Publication Date:
OSTI Identifier:
22661321
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 837; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BLACK HOLES; CATALOGS; EVOLUTION; GALAXIES; GALAXY NUCLEI; MASS; NASA; X RADIATION; X-RAY SOURCES

Citation Formats

Nucita, A. A., Manni, L., Paolis, F. De, Giordano, M., and Ingrosso, G., E-mail: nucita@le.infn.it. A Catalog Sample of Low-mass Galaxies Observed in X-Rays with Central Candidate Black Holes. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA5F4F.
Nucita, A. A., Manni, L., Paolis, F. De, Giordano, M., & Ingrosso, G., E-mail: nucita@le.infn.it. A Catalog Sample of Low-mass Galaxies Observed in X-Rays with Central Candidate Black Holes. United States. doi:10.3847/1538-4357/AA5F4F.
Nucita, A. A., Manni, L., Paolis, F. De, Giordano, M., and Ingrosso, G., E-mail: nucita@le.infn.it. Wed . "A Catalog Sample of Low-mass Galaxies Observed in X-Rays with Central Candidate Black Holes". United States. doi:10.3847/1538-4357/AA5F4F.
@article{osti_22661321,
title = {A Catalog Sample of Low-mass Galaxies Observed in X-Rays with Central Candidate Black Holes},
author = {Nucita, A. A. and Manni, L. and Paolis, F. De and Giordano, M. and Ingrosso, G., E-mail: nucita@le.infn.it},
abstractNote = {We present a sample of X-ray-selected candidate black holes in 51 low-mass galaxies with z ≤ 0.055 and masses up to 10{sup 10} M {sub ⊙} obtained by cross-correlating the NASA-SLOAN Atlas with the 3XMM catalog. We have also searched in the available catalogs for radio counterparts of the black hole candidates and find that 19 of the previously selected sources also have a radio counterpart. Our results show that about 37% of the galaxies of our sample host an X-ray source (associated with a radio counterpart) spatially coincident with the galaxy center, in agreement with other recent works. For these nuclear sources, the X-ray/radio fundamental plane relation allows one to estimate the mass of the (central) candidate black holes, which are in the range of 10{sup 4}–2 × 10{sup 8} M {sub ⊙} (with a median value of ≃3 × 10{sup 7} M {sub ⊙} and eight candidates having masses below 10{sup 7} M {sub ⊙}). This result, while suggesting that X-ray emitting black holes in low-mass galaxies may have had a key role in the evolution of such systems, makes it even more urgent to explain how such massive objects formed in galaxies. Of course, dedicated follow-up observations both in the X-ray and radio bands, as well as in the optical, are necessary in order to confirm our results.},
doi = {10.3847/1538-4357/AA5F4F},
journal = {Astrophysical Journal},
number = 1,
volume = 837,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2017},
month = {Wed Mar 01 00:00:00 EST 2017}
}
  • We report the discovery of three low-mass black hole (BH) candidates residing in the centers of low-mass galaxies at z < 0.3 in the Chandra Deep Field-South Survey. These BHs are initially identified as candidate active galactic nuclei based on their X-ray emission in deep Chandra observations. Multi-wavelength observations are used to strengthen our claim that such emission is powered by an accreting supermassive BH. While the X-ray luminosities are low at L{sub X} {approx} 10{sup 40} erg s{sup -1} (and variable in one case), we argue that they are unlikely to be attributed to star formation based on H{alpha}more » or UV fluxes. Optical spectroscopy from Keck and the VLT allows us to (1) measure accurate redshifts, (2) confirm their low stellar host mass, (3) investigate the source(s) of photo-ionization, and (4) estimate extinction. With stellar masses of M{sub *} < 3 Multiplication-Sign 10{sup 9} M{sub Sun} determined from Hubble Space Telescope/Advanced Camera for Surveys imaging, the host galaxies are among the lowest mass systems known to host actively accreting BHs. We estimate BH masses M{sub BH} {approx} 2 Multiplication-Sign 10{sup 5} M{sub Sun} based on scaling relations between BH mass and host properties for more luminous systems. In one case, a broad component of the H{alpha} emission-line profile is detected, thus providing a virial mass estimate. BHs in such low-mass galaxies are of considerable interest as the low-redshift analogs to the seeds of the most massive BHs at high redshift which have remained largely elusive to date. Our study highlights the power of deep X-ray surveys to uncover such low-mass systems.« less
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