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Register a new userSDSS J013127.34-032100.1: a candidate blazar with a 11 billion solar mass black hole at $z$=5.18
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Added by
Gabriele Ghisellini
Publication date
2015
fields
Physics
and research's language is
English
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The radio-loud quasar SDSS J013127.34-032100.1at a redshift z=5.18 is one of the most distant radio-loud objects. The radio to optical flux ratio (i.e. the radio-loudness) of the source is large, making it a promising blazar candidate. Its overall spectral energy distribution, completed by the X-ray flux and spectral slope derived through Target of Opportunity Swift/XRT observations, is interpreted by a non-thermal jet plus an accretion disc and molecular torus model. We estimate that its black hole mass is (1.1+-0.2)1e10 Msun. for an accretion efficiency eta=0.08, scaling roughly linearly with eta. Although there is a factor ~2 of systematic uncertainty, this black hole mass is the largest found at these redshifts in a radio loud object. We derive a viewing angle between 3 and 5 degrees. This implies that there must be other (hundreds) sources with the same black hole mass of SDSS J013127.34-032100.1, but whose jets are pointing away from Earth. We discuss the problems posed by the existence of such large black hole masses at such redshifts, especially in jetted quasars. In fact, if they are associated to rapidly spinning black holes, the accretion efficiency is high, implying a slower pace of black hole growth with respect to radio-quiet quasars.
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We report on X-ray measurements constraining the spectral energy distribution (SED) of the high-redshift $z=5.18$ blazar SDSS J013127.34$-$032100.1 with new XMM-Newton and NuSTAR exposures. The blazars X-ray spectrum is well fit by a power law with $Gamma=1.9$ and $N_{rm H}=1.1times10^{21}rm cm^{-2}$, or a broken power law with $Gamma_l=0.5$, $Gamma_h=1.8$, and a break energy $E_b=0.7$ keV for an expected absorbing column density of $N_{rm H}=3.6times 10^{20}rm cm^{-2}$, supported by spectral fitting of a nearby bright source. No additional spectral break is found at higher X-ray energies (1-30 keV). We supplement the X-ray data with lower-energy radio-to-optical measurements and Fermi-LAT gamma-ray upper limits, construct broadband SEDs of the source, and model the SEDs using a synchro-Compton scenario. This modeling constrains the bulk Doppler factor of the jets to $ge$7 and $ge$6 (90%) for the low- and high-$N_{rm H}$ SEDs, respectively. The corresponding beaming implies $ge$130 (low $N_{rm H}$) or $ge$100 (high $N_{rm H}$) high-spin supermassive black holes similar to J0131 exist at similar redshifts.
Only very few z>5 quasars discovered to date are radio-loud, with a radio-to-optical flux ratio (radio-loudness parameter) higher than 10. Here we report the discovery of an optically luminous radio-loud quasar, SDSS J013127.34-032100.1 (J0131-0321 in short), at z=5.18+-0.01 using the Lijiang 2.4m and Magellan telescopes. J0131-0321 has a spectral energy distribution consistent with that of radio-loud quasars. With an i-band magnitude of 18.47 and radio flux density of 33 mJy, its radio-loudness parameter is ~100. The optical and near-infrared spectra taken by Magellan enable us to estimate its bolometric luminosity to be L_bol ~ 1.1E48 erg/s, approximately 4.5 times greater than that of the most distant quasar known to date. The black hole mass of J0131-0321 is estimated to be 2.7E9 solar masses, with an uncertainty up to 0.4 dex. Detailed physical properties of this high-redshift, radio-loud, potentially super-Eddington quasar can be probed in the future with more dedicated and intensive follow-up observations using multi-wavelength facilities.
We report the discovery of an ultra-luminous quasar J030642.51+185315.8 (hereafter J0306+1853) at redshift 5.363, which hosts a super-massive black hole (SMBH) with $M_{BH} = (1.07 pm 0.27) times10^{10}~M_odot$. With an absolute magnitude $M_{1450}=-28.92$ and bolometric luminosity $L_{bol}sim3.4times10^{14} L_{odot}$, J0306+1853 is one of the most luminous objects in the early Universe. It is not likely to be a beamed source based on its small flux variability, low radio loudness and normal broad emission lines. In addition, a $z=4.986$ Damped Ly$alpha$ system (DLA) with $rm [M/H]=-1.3pm0.1$, among the most metal rich DLAs at $z gtrsim 5$, is detected in the absorption spectrum of this quasar. This ultra-luminous quasar puts strong constraint on the bright-end of quasar luminosity function and massive-end of black hole mass function. It will provide a unique laboratory to the study of BH growth and the co-evolution between BH and host galaxy with multi-wavelength follow-up observations. The future high resolution spectra will give more insights to the DLA and other absorption systems along the line-of-sight of J0306+1853.
We report the discovery of a luminous quasar, J1007+2115 at $z=7.515$ (P={o}niu={a}ena), from our wide-field reionization-era quasar survey. J1007+2115 is the second quasar now known at $z>7.5$, deep into the reionization epoch. The quasar is powered by a $(1.5pm0.2)times10^9$ $M_{odot}$ supermassive black hole (SMBH), based on its broad MgII emission-line profile from Gemini and Keck near-IR spectroscopy. The SMBH in J1007+2115 is twice as massive as that in quasar J1342+0928 at $z=7.54$, the current quasar redshift record holder. The existence of such a massive SMBH just 700 million years after the Big Bang significantly challenges models of the earliest SMBH growth. Model assumptions of Eddington-limited accretion and a radiative efficiency of 0.1 require a seed black hole of $gtrsim 10^{4}$ $M_{odot}$ at $z=30$. This requirement suggests either a massive black hole seed as a result of direct collapse or earlier periods of rapid black hole growth with hyper-Eddington accretion and/or a low radiative efficiency. We measure the damping wing signature imprinted by neutral hydrogen absorption in the intergalactic medium (IGM) on J1007+2115s Ly$alpha$ line profile, and find that it is weaker than that of J1342+0928 and two other $zgtrsim7$ quasars. We estimate an IGM volume-averaged neutral fraction $langle xrm_{HI}rangle=0.39^{+0.22}_{-0.13}$. This range of values suggests a patchy reionization history toward different IGM sightlines. We detect the 158 $mu$m [C II] emission line in J1007+2115 with ALMA; this line centroid yields a systemic redshift of $z=7.5149pm0.0004$ and indicates a star formation rate of $sim210$ $M_{odot}$ yr$^{-1}$ in its host galaxy.
On June 8, 2017 at 02:01:16.49 UTC, a gravitational-wave signal from the merger of two stellar-mass black holes was observed by the two Advanced LIGO detectors with a network signal-to-noise ratio of 13. This system is the lightest black hole binary so far observed, with component masses $12^{+7}_{-2},M_odot$ and $7^{+2}_{-2},M_odot$ (90% credible intervals). These lie in the range of measured black hole masses in low-mass X-ray binaries, thus allowing us to compare black holes detected through gravitational waves with electromagnetic observations. The sources luminosity distance is $340^{+140}_{-140}$ Mpc, corresponding to redshift $0.07^{+0.03}_{-0.03}$. We verify that the signal waveform is consistent with the predictions of general relativity.
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