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Metal-THINGS: on the metallicity and ionization of ULX sources in NGC 925

We present an analysis of the optical properties of three Ultra Luminous X-ray (ULX) sources identified in NGC 925. We use Integral field unit data from the George Mitchel spectrograph in the context of the Metal-THINGS survey. The optical properties for ULX-1 and ULX-3 are presented, while the spax...

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Main Authors: Lara-López, Maritza A. (Author) , Zinchenko, Igor A. (Author) , Pilyugin, Leonid S. (Author) , Gunawardhana, Madusha L. P. (Author) , López-Cruz, Omar (Author) , Sullivan, Shane P. O' (Author) , Feltre, Anna (Author) , Rosado, Margarita (Author) , Sánchez-Cruces, Mónica (Author) , Chevallard, Jacopo (Author) , Rossi, Maria Emilia De (Author) , Dib, Sami (Author) , Fritz, Jacopo (Author) , Fuentes-Carrera, Isaura (Author) , Garduño, Luis E. (Author) , Ibar, Eduardo (Author)
Format: Article (Journal)
Language:English
Published: 2021 January 5
In: The astrophysical journal
Year: 2021, Volume: 906, Issue: 1
ISSN:1538-4357
DOI:10.3847/1538-4357/abc892
Online Access:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.3847/1538-4357/abc892
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Author Notes:Maritza A. Lara-López, Igor A. Zinchenko, Leonid S. Pilyugin, Madusha L.P. Gunawardhana, Omar López-Cruz, Shane P. O' Sullivan, Anna Feltre, Margarita Rosado, Mónica Sánchez-Cruces, Jacopo Chevallard, Maria Emilia De Rossi, Sami Dib, Jacopo Fritz, Isaura Fuentes-Carrera, Luis E. Garduño, and Eduardo Ibar
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Summary:We present an analysis of the optical properties of three Ultra Luminous X-ray (ULX) sources identified in NGC 925. We use Integral field unit data from the George Mitchel spectrograph in the context of the Metal-THINGS survey. The optical properties for ULX-1 and ULX-3 are presented, while the spaxel associated with ULX-2 had a low S/N, which prevented its analysis. We also report the kinematics and dimensions of the optical nebula associated with each ULX using ancillary data from the PUMA Fabry-Perot spectrograph. A BPT analysis demonstrates that most spaxels in NGC 925 are dominated by star-forming regions, including those associated with ULX-1 and ULX-3. Using the resolved gas-phase metallicities, a negative metallicity gradient is found, consistent with previous results for spiral galaxies, while the ionization parameter tends to increase radially throughout the galaxy. Interestingly, ULX-1 shows a very low gas metallicity for its galactocentric distance, identified by two independent methods, while exhibiting a typical ionization. We find that such low gas metallicity is best explained in the context of the high-mass X-ray binary population, where the low-metallicity environment favors active Roche lobe overflows that can drive much higher accretion rates. An alternative scenario invoking accretion of a low-mass galaxy is not supported by the data in this region. Finally, ULX-3 shows both a high metallicity and ionization parameter, which is consistent with the progenitor being a highly accreting neutron star within an evolved stellar population region.
Item Description:Gesehen am 12.02.2021
Physical Description:Online Resource
ISSN:1538-4357
DOI:10.3847/1538-4357/abc892

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