Leo I dwarf galaxy has a stunningly large SMBH

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notFritzArgelander
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Leo I dwarf galaxy has a stunningly large SMBH

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Post by notFritzArgelander »


at least for its size. Very little DM is present too. (Take that you MONDians!),

https://phys.org/news/2021-12-astronome ... -hole.html
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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Re: Leo I dwarf galaxy has a stunningly large SMBH

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Post by helicon »


It seems like most galaxies, even dwarves, have SMBH's at their center. Normal part of astrophysics, I suppose.
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Re: Leo I dwarf galaxy has a stunningly large SMBH

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Post by notFritzArgelander »


helicon wrote: Thu Dec 02, 2021 4:00 pm It seems like most galaxies, even dwarves, have SMBH's at their center. Normal part of astrophysics, I suppose.
What is abnormal about this is the size of the SMBH relative to that of the galaxy. The situation is a subject of intense debate. The article claims that Leo I is the odd duck because it's SMBH is surprisingly massive. OTOH one might argue that the Milky Way's SMBH is surprisingly light. The whole situation is unclear.

https://aasnova.org/2020/09/30/the-link ... -galaxies/

Shows that there are three leading hypotheses for such a relationship, one of them being that it is a meaningless statistical fluke. :)

The most recent reference I know of takes the relationship seriously https://arxiv.org/abs/1910.11875
Correlations between the mass of a supermassive black hole and the properties of its host galaxy (e.g., total stellar mass (M*), luminosity (Lhost)) suggest an evolutionary connection. A powerful test of a co-evolution scenario is to measure the relations MBH-Lhost and MBH-M* at high redshift and compare with local estimates. For this purpose, we acquired HST imaging with WFC3 of 32 X-ray-selected broad-line AGN at 1.2<z<1.7 in deep survey fields. By applying state-of-the-art tools to decompose the HST images including available ACS data, we measured the host galaxy luminosity and stellar mass along with other properties through the 2D model fitting. The black hole mass was determined using the broad Halpha line, detected in the near-infrared with Subaru/FMOS, which potentially minimizes systematic effects using other indicators. We find that the observed ratio of MBH to total M* is 2.7 times larger at z~1.5 than in the local universe, while the scatter is equivalent between the two epochs. A non-evolving mass ratio is consistent with the data at the 2-3 sigma confidence level when accounting for selection effects and their uncertainties. The relationship between MBH-Lhost paints a similar picture. Therefore, our results cannot distinguish whether SMBHs and their total M* and Lhost proceed in lockstep or whether the growth of the former somewhat overshoots the latter, given the uncertainties. Based on a statistical estimate of the bulge-to-total mass fraction, the ratio MBH/M* is offset from the local value by a factor of ~7 which is significant even accounting for selection effects. Taken together, these observations are consistent with a scenario in which stellar mass is subsequently transferred from an angular momentum supported component of the galaxy to the pressure supported one through secular processes or minor mergers at a faster rate than mass accretion onto the SMBH.
The only part of this that is settled is the relationship that determined the mass of Leo I's SMBH.

https://en.wikipedia.org/wiki/M–sigma_relation
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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