Photography, Digital

Kriss, Michael A.

doi:10.1002/3527600434.eap584.pub2

Cited by 1 publication

(1 citation statement)

References 41 publications

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“…So, in the search for intermediate mass BHs, this would be the best emission line to target. OVI is hard to detect, however, as it requires far UV spectroscopy at low redshifts, as from FUSE (Kriss 2004), while at high redshifts it is almost always absorbed by the Lyman alpha forest. Figure 19 shows the line ratios for the entire mass range, for BELs (top panels) and NELs (bottom panels).…”

Section: Emission Line Strengths In Lower Mass Schwarzchild Black Holesmentioning

confidence: 99%

Hypermassive black holes have faint broad and narrow emission lines

Bhat

Chakravorty

Sengupta

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Abstract The EUV provides most of the ionization that creates the high equivalent width (EW) broad and narrow emission lines (BELs, NELs) of quasars. Spectra of Hypermassive Schwarzschild black holes (HMBHs, MBH ≥ 1010M⊙) with α-discs, decline rapidly in the EUV suggesting much lower EWs. Model spectra for black holes of mass 106 − 1012M⊙ and accretion rates 0.03 ≤ Lbol/Ledd ≤ 1.0 were input to the CLOUDY photoionization code. BELs become ∼100 times weaker in EW from MBH ∼ 108M⊙ to MBH ∼ 1010M⊙. The high ionization BELs (O VI 1034 Å, C IV 1549 Å, He II 1640 Å) decline in EW from (MBH ≥ 106M⊙, reproducing the Baldwin effect, but regain EW for MBH ≥ 1010M⊙). The low ionization lines (MgII 2798 Å, Hβ 4861 Å and Hα 6563 Å) remain weak. Lines for maximally spinning HMBHs behave similarly. Line ratio diagrams for the BELs show that high OVI/Hβ and low CIV/Hα may pick out HMBH, although OVI is often hard to observe. In NEL BPT diagrams HMBHs lie among star forming regions, except for highly spinning, high accretion rate HMBHs. In summary, the BELs expected from HMBHs would be hard to detect using the current optical facilities. From 100 to 1012M⊙, the emission lines used to detect AGN only have high EW in the 106 − 109M⊙ window, where most AGN are found. This selection effect may be distorting reported distributions of MBH.

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Section: Emission Line Strengths In Lower Mass Schwarzchild Black Holesmentioning

confidence: 99%