Hyper-massive Black Holes have Faint Broad and Narrow Emission Lines. (arXiv:2007.01438v1 [astro-ph.GA])

Hyper-massive Black Holes have Faint Broad and Narrow Emission Lines. (arXiv:2007.01438v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Bhat_H/0/1/0/all/0/1">Harshitha K. Bhat</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chakravorty_S/0/1/0/all/0/1">Susmita Chakravorty</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sengupta_D/0/1/0/all/0/1">Dhrubojyoti Sengupta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Elvis_M/0/1/0/all/0/1">Martin Elvis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Datta_S/0/1/0/all/0/1">Sudeb Ranjan Datta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Roy_N/0/1/0/all/0/1">Nirupam Roy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bertemes_C/0/1/0/all/0/1">Caroline Bertemes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ferland_G/0/1/0/all/0/1">Gary Ferland</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ezhikode_S/0/1/0/all/0/1">Savithri H. Ezhikode</a>

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, $M_{BH} geq 10^{10} M_{odot}$)
with $alpha$-discs, decline rapidly in the EUV suggesting much lower EWs.
Model spectra for black holes of mass $10^{6}-10^{12} M_{odot}$ and accretion
rates $0.03 leq L_{bol}/L_{edd} leq 1.0$ were input to the CLOUDY
photoionization code. BELs become $sim$100 times weaker in EW from $M_{BH}
sim 10^8 M_{odot}$ to $M_{BH} sim 10^{10} M_{odot}$. The high ionization
BELs (O VI 1034 $overset{circ}{mathrm {A}}$, C IV 1549
$overset{circ}{mathrm {A}}$, He II 1640 $overset{circ}{mathrm {A}}$)
decline in EW from ($M_{BH} geq 10^6 M_{odot}$, reproducing the Baldwin
effect, but regain EW for $M_{BH} geq 10^{10} M_{odot}$). The low ionization
lines (MgII 2798 $overset{circ}{mathrm {A}}$, H$beta$ 4861
$overset{circ}{mathrm {A}}$ and H$alpha$ 6563 $overset{circ}{mathrm
{A}}$) remain weak. Lines for maximally spinning HMBHs behave similarly. Line
ratio diagrams for the BELs show that high OVI/H$beta$ and low CIV/H$alpha$
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 $10^{12} M_{odot}$,
the emission lines used to detect AGN only have high EW in the $10^6 – 10^9
M_{odot}$ window, where most AGN are found. This selection effect may be
distorting reported distributions of $M_{BH}$.

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, $M_{BH} geq 10^{10} M_{odot}$)
with $alpha$-discs, decline rapidly in the EUV suggesting much lower EWs.
Model spectra for black holes of mass $10^{6}-10^{12} M_{odot}$ and accretion
rates $0.03 leq L_{bol}/L_{edd} leq 1.0$ were input to the CLOUDY
photoionization code. BELs become $sim$100 times weaker in EW from $M_{BH}
sim 10^8 M_{odot}$ to $M_{BH} sim 10^{10} M_{odot}$. The high ionization
BELs (O VI 1034 $overset{circ}{mathrm {A}}$, C IV 1549
$overset{circ}{mathrm {A}}$, He II 1640 $overset{circ}{mathrm {A}}$)
decline in EW from ($M_{BH} geq 10^6 M_{odot}$, reproducing the Baldwin
effect, but regain EW for $M_{BH} geq 10^{10} M_{odot}$). The low ionization
lines (MgII 2798 $overset{circ}{mathrm {A}}$, H$beta$ 4861
$overset{circ}{mathrm {A}}$ and H$alpha$ 6563 $overset{circ}{mathrm
{A}}$) remain weak. Lines for maximally spinning HMBHs behave similarly. Line
ratio diagrams for the BELs show that high OVI/H$beta$ and low CIV/H$alpha$
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 $10^{12} M_{odot}$,
the emission lines used to detect AGN only have high EW in the $10^6 – 10^9
M_{odot}$ window, where most AGN are found. This selection effect may be
distorting reported distributions of $M_{BH}$.

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