J/A+A/682/A36ivo://CDS.VizieR/J/A+A/682/A36doi:10.26093/cds/vizier.36820036CDSHoyer N.Arcodia R.Bonoli S.Merloni A.Neumayer N.Zhang Y.,Comparat J.2024-11-28T20:06:31Z2024-01-31T12:49:24ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frgalaxiesx-ray-sourcesstellar-associationsMassive black holes (MBHs) are typically hosted in the centres of massive galaxies but they appear to become rarer in lower mass galaxies, where nuclear star clusters (NSCs) frequently appear instead. The transition region, where both an MBH and NSC can co-exist, has been poorly studied to date and only a few dozen galaxies are known to host them. One avenue for detecting new galaxies with both an MBH and NSC is to look for accretion signatures of MBHs. Here, we use new SRG/eROSITA all-sky survey eRASS:4 data to search for X-ray signatures of accreting MBHs in NSCs, while also investigating their combined occupation fraction. We collected more than 200 galaxies containing an NSC, spanning multiple orders in terms of galaxy stellar mass and morphological type, within the footprint of the German eROSITA Consortium survey. We determined the expected X-ray contamination from binary stellar systems using the galaxy stellar mass and star formation rate as estimated from far-ultraviolet and mid-infrared emission. We find significant detections for 18 galaxies (~8.3%), including one ultra-luminous X-ray source; however, only three galaxies (NGC 2903, 4212, and 4639) have X-ray luminosities that are higher than the expected value from X-ray binaries, indicative of the presence of an MBH. In addition, the X-ray luminosity of six galaxies (NGC 2903, 3384, 4321, 4365, 4639, and 4701) differs from previous studies and could indicate the presence of a variable active galactic nucleus. For NGC 4701 specifically, we find a variation of X-ray flux within the eRASS:4 data set. Stacking X-ray non-detected galaxies in the dwarf regime M*gal<=10^9^M_{sun}_) results in luminosity upper limits of a few times 10^38^erg/s. The combined occupation fraction of accreting MBHs and NSCs becomes non-zero for galaxy masses above ~10^7.5^M_{sun}_ and this result is slightly elevated as compared to the literature data. Our data extend, for the first time, towards the dwarf elliptical galaxy regime and identify promising MBH candidates for higher resolution follow-up observations. At most galaxy masses (and with the exception of three cases), the X-ray constraints are consistent with the expected emission from binary systems or an Eddington fraction of at most 0.01%, assuming a black holes mass of 10^6.5^M_{sun}_. This work confirms the known complexities in similar-type of studies, while providing the appealing alternative of using X-ray survey data of in-depth observations of individual targets with higher resolution instruments.2024A&A...682A..36Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/682/A36CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/682/A36https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/682/A36http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/682/A36https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/682/A36https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/682/A36http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/682/A36GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/682/A36/table1 (Galaxy properties and X-ray luminosities in the 2-10keV range from eRASS:4)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/682/A36/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/682/A36/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/682/A36/table1?GETtext/xml+votable180.050000true179.6837527.5850.0055555555555555565/6878 6935 6941 6965 6978 6/4181 4405 4511 4989 4991 5142 5174 5329 8225 10240 22427 25966 26068 26217 26222 26234 26265 26315 26317 26338 26353 26361 26388 26542 27458 27518 27603-27604 27606 27718-27719 27721 27724 27730-27731 27733-27736 27738-27739 27763 27769-27771 27773-27774 27823 27858-27859 27904 27907-27908 27910 27916 27918-27919 27926 27936 27938 27941-27945 27948-27949 27951 27955 28032-28033 28035 28037-28038 28045 28053 28077 28172 28200 28294 28471 28476 28486 28496 28517 28523 28612https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/682/A36?format=asciiX-raydefaultJ/A+A/682/A36/table1Galaxy properties and X-ray luminosities in the 2-10keV range from eRASS:4SimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGalaxyGalaxy name (galaxy)meta.id;meta.maincharRAJ2000Right ascension (J2000) (ra)degpos.eq.ra;meta.mainDEJ2000Declination (J2000) (dec)degpos.eq.dec;meta.maindistmod? Distance modulus (distmod)magphot.mag.distModfloatnullablee_distmod? Uncertainty on the distance modulus (u_distmod)magstat.errorfloatnullableTType? Morphological Hubble type (ttype)src.morph.typefloatnullablee_TType? Uncertainty on the morphological Hubble type (u_ttype)meta.notefloatnullableloggalmass? Logarithmic galaxy stellar mass (galmass)log(solMass)phys.massfloatnullablee_loggalmass? Uncertainty on the logarithmic galaxy stellar mass (u_galmass)log(solMass)stat.errorfloatnullablelogSFR? Logarithmic star formation rate (logsfr)log(solMass.yr**-1)meta.iddoublenullablee_logSFR? Uncertainty on the logarithmic star formation rate (u_logsfr)log(solMass.yr**-1)stat.error;phys.SFRdoublenullableLumMed2-10? Median luminosity in the 2-10keV band (lum_median_2to10)1e-07Wphys.luminosity;em.X-raydoublenullableLum1st2-10? 1st percentile of the luminosity in the 2-10keV band (lum_1st_2to10)1e-07Wphys.luminosity;em.X-raydoublenullableLum99th2-10? 99th percentile of the luminosity in the 2-10keV band (lum_99th_2to10)1e-07Wphys.luminosity;em.X-raydoublenullableLumbin? Expected luminosity from binary systems (lum_binary)1e-07Wphys.luminosity;em.X-raydoublenullablee_Lumbin? Uncertainty on the expected luminosity from binary systems (u_lum_binary)1e-07Wstat.errordoublenullableTExp? eRASS:4 total exposure time (t_exp)stime.duration;obs.exposurefloatnullablepbinom[0/1] Binomial probability that the detection is a background fluctuation (p_binom)stat.fit.goodnessdouble