OBSERVATION EVIDENCES FOR THIS PICTURE That Astrophysical BHCs/MCOs are MECOs
If the BHCs are ECOs, which is much more compact than typical Neutron Stars and horizonless, they are expected to possess INTRINSIC magnetic field (B) much stronger than that of neutron stars. Indeed, way back in 2002, in a pioneering paper,
Ref 1. ``Evidence for Intrinsic Magnetic Moments in Black Hole Candidates''
The Astrophysical Journal, Volume 565, Issue 1, pp. 447-454 (2002); http://arxiv.org/abs/astro-ph/0102381
Robertson & Leiter showed that the so-called BHs in the X-Ray binaries may be explained as ultramagnetized ECOs. Later the name Magnetospheric ECOs or MECOs were invented. Later these authors went on strengthening this idea in several other important peer reviewed papers in top journals:
Ref 2. On Intrinsic Magnetic Moments in Black Hole Candidates
Astrophysical Journal, Volume 596, L203-L206 (2003); http://arxiv.org/abs/astro-ph/0310078
Ref 3. On the origin of the universal radio-X-ray luminosity correlation in black hole candidates:
Monthly Notices of the Royal Astronomical Society, Volume 350, 1391 (2004); http://arxiv.org/abs/astro-ph/0402445
In 2006, almost direct (by astrophysical standards) evidence was presented that the BHC in the most well studied quasar is a MECO:
Ref 4. Observations Supporting the Existence of an Intrinsic Magnetic Moment inside the Central Compact Object within the Quasar Q0957+561
Schild, Rudolph E.; Leiter, Darryl J.; Robertson, Stanley L.: Astronomical Journal, 132, 420 (2006); http://arxiv.org/abs/astro-ph/0505518
Here is the link for Center for Astrophysics, Harvard, press release on this pioneering research: http://www.cv.nrao.edu/tuna/past/2006/NEW_QSO_STRUCTURE_FOUND.pdf
Later it was found that many other quasars are likely to possess MECOs rather than BHs as their central engines:
Ref. 5. Schild, Rudolph E.; Leiter, Darryl J.; Robertson, Stanley L.:
``Direct Microlensing-Reverberation Observations of the Intrinsic Magnetic Structure of Active Galactic Nuclei in Different Spectral States: A Tale of Two Quasars''
Astronomical Journal, 135, 947-956 (2008); http://arxiv.org/abs/0708.2422
Ref. 6. Lovegrove, Justin; Schild, Rudolph E.; Leiter, Darryl.: Discovery of universal outflow structures above and below the accretion disc plane in radio-quiet quasars'
Monthly Notices of the Royal Astronomical Society, 412, 2631-2640 (2011).
Thus the idea that the BHCs are ECOs/MECOs have excellent observational support unlike any other hypothesis.
Regards
Abhas