LeMMINGs - IV. The X-ray properties of a statistically complete sample of the nuclei in active and inactive galaxies from the Palomar sample

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Oxford University Press/Royal Astronomical Society
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All 280 of the statistically complete Palomar sample of nearby (<120 Mpc) galaxies delta > 20 degrees have been observed at 1.5 GHz as part of the LeMMINGs e-MERLIN legacy survey. IIere, we present Chandra X-ray observations of the nuclei of 213 of these galaxies, including a statistically complete sub-set of 113 galaxies in the declination range 40 degrees <delta < 65 degrees. We observed galaxies of all optical spectral types, including 'active' galaxies [e.g. low-ionization nuclear emission line regions (LINERs) and Seyferts] and 'inactive' galaxies like H II galaxies and absorption line galaxies (ALG). The X-ray flux limit of our survey is 1.65 x 10(-14) erg s(-1) cm(-2) (0.3-10 keV). We detect X-ray emission coincident within 2 arcsec of the nucleus in 150/213 galaxies, including 13/14 Seyferts, 68/77 LINERs, 13/22 ALGs and 56/100 H II galaxies, but cannot completely rule out contamination from non-AGN processes in sources with nuclear luminosities less than or similar to 10(39) erg s(-1). We construct an X-ray Luminosity function (XI,F) and find that the local galaxy XLF, when including all active galactic nucleus (AGN) types, can be represented as a single power law of slope -0.54 +/- 0.06. The Eddington ratio of the Seyferts is usually 2-4 decades higher than that of the LINERs, ALGs, and H II galaxies, which are mostly detected with Eddington ratios less than or similar to 10(-3). Using [O III] line measurements and black hole masses from the literature, we show that LINERs, H II galaxies and ALGs follow similar correlations to low luminosities, suggesting that some 'inactive' galaxies may harbour AGN.
Artículo firmado por 25 autores. We would like to acknowledge the support of the LeMMINGs project, upon which this study is based. We acknowledge funding from the Mayflower Scholarship from the University of Southampton afforded to David Williams to complete this work. This work was also supported by the Oxford Centre for Astrophysical Surveys, which is funded through generous support from the Hintze Family Charitable Foundation. MP acknowledges Royal Society-SERB Newton International Fellowship support funded jointly by the Royal Society, UK and the Science and Engineering Board of India (SERB) through Newton-Bhabha Fund. IMcH thanks the Royal Society for the award of a Royal Society Leverhulme Trust Senior Research Fellowship. RDB and IMcH also acknowledge the support of STFC under grant [ST/M001326/1]. SM gratefully acknowledges the support from the Chandra grant GO7-18080X issued by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060. AB is grateful to the Royal Society and SERB (Science and Engineering Research Board, India). AB is supported by an INSPIRE Faculty grant (DST/INSPIRE/04/2018/001265) by the Department of Science and Technology, Govt. of India. PGB acknowledges financial support from the STFC and the Czech Science Foundation project No. 19-05599Y. SA gratefully acknowledges support from an ERC Advanced Grant 789410 JHK acknowledges financial support from the European Union's Horizon 2020 research and innovation programme under Marie Skodowska-Curie grant agreement no. 721463 to the SUNDIAL ITN network, from the State Research Agency (AEI-MCINN) of the Spanish Ministry of Science and Innovation under the grant 'The structure and evolution of galaxies and their central regions' with reference PID2019-105602GB-I00/10.13039/501100011033, and from IAC project P/300724, financed by the Ministry of Science and Innovation, through the State Budget and by the Canary Islands Department of Economy, Knowledge, and Employment, through the Regional Budget of the Autonomous Community. BTD acknowledges support from a Spanish postdoctoral fellowship 'Ayudas 1265 para la atracción del talento investigador. Modalidad 2: jóvenes investigadores.' funded by Comunidad de Madrid under grant number 2016-T2/TIC-2039 and support from grant 'Ayudas para la realización de proyectos de I + D para jóvenes doctores 2019.' funded by Comunidad de Madrid and Universidad Complutense de Madrid under grant number PR65/19-22417. AA and MAPT acknowledge support from the Spanish MCIU through grant PGC2018-098915-B-C21. JM acknowledges support from the grant RTI2018-096228-B-C31 (MICIU/FEDER, EU). AA, MAPT, and JM acknowledge financial support from the State Agency for Research of the Spanish MCIU through the 'Center of Excellence Severo Ochoa' award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). CGM acknowledges support from Mrs Hiroko and Mr Jim Sherwin. FS acknowledges partial support from a Leverhulme Trust Research Fellowship. We also acknowledge Jodrell Bank Centre for Astrophysics, which is funded by the STFC. e-MERLIN and formerly, MERLIN, is a National Facility operated by the University of Manchester at Jodrell Bank Observatory on behalf of STFC. The scientific results reported in this article are based to a significant degree on observations made by the Chandra X-ray Observatory and on data obtained from the Chandra Data Archive.; This research has made use of software provided by the Chandra X-ray Center (CXC) in the application package ciao. DW would also like to thank Sam Connolly, Dimitrios Emmanolopoulos, and Sara Motta for useful discussions.
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