Black Holes and Quasars

The research is directed at finding environmental factors that are related to the switch-on of the general relativistic engine responsible for the few percent of accreting black holes that drive powerful relativistic jets. This is important since this will relate directly to constraints on the initial state and boundary conditions on numerical models of black hole driven jets.

Topics of research:
• long term 3-D MHD numerical simulations of black hole magnetospheres
• in depth high resolution VLBA monitoring of the nearby quasar MRK 231
• X-ray observations of quasars with polar broad UV absorption line outflows
• propensity for red (redward of the QSO systemic velocity) broad line emission excess in radio loud quasars that is accentuated for polar lines of sight
• discovery of excess narrow line widths of broad emission lines in broad absorption line quasars
• finding environmental factors that are related to the switch-on of the general relativistic engine responsible for a few percent of quasars driving powerful relativistic jets
• the study of 3-D numerical simulations of black hole magnetospheres and how they relate to observations of astrophysical jets
• using the jet in the Galactic black hole, GRS 1915+105, as a test case for black hole driven jets

Group leader: Prof. Brian Punsly (Mathew California University, Los Angeles USA)

Brief description

Prof. Brian Punsly is actively collaborating with ICRANet with the publication of his internationally recognized book on "Black hole gravitohydromagnetics", the first and second edition (2008) being published with Springer.
Prof. Punsly have been interested in observational properties of quasars such as broad line emission excess in radio loud quasars accentuated for polar line of sight and excess narrow line widths of broad emission lines in broad absorption line quasars, showing that this is best explained by polar lines of sight.
He was leading collaborations to perform high frequency (high resolution), time resolved VLBA observations of broad absorption line quasars.

The Origin of the Event Horizon Scale Jet in M87
Global millimeter wavelength Very Long Baseline Interferometry (VLBI) is an ambitious program to study the event horizon scale physics of nearby active galactic nuclei (AGN). The shortest wavelength receivers have been designated as the Event Horizon Telescope (EHT). It has been widely advertised that the experiment will reveal how astrophysical black holes can drive powerful jets near the event horizon –possibly proving the Blandford-Znajek mechanism that drives jets from the event horizon itself. There is only one powerful relativistic jet source that can be explored by the EHT with resolution on the order of the event horizon dimension, the jet in the enormous radio galaxy M87. Thus, M87 is the most studied object in radio jet research.
There is radio imaging of M87at 3.5 mm (86 GHz) and detections with the EHT at 1.3 mm (230 GHz). The newest t and most sensitive 86 GHz published image is shown in Figure 1. There is currently no imaging capability at 230 GHz. However, it seems clear from the 86 GHz image in Figure 1 that there is a flux void along the central spine above the event horizon. More specifically, the image reveals a central flux nadir within 50M (where M is the black hole in geometrized units) of the super-massive black hole. ICRANet adjunct professor, Brian Punsly, has been collaborating with Kazuhiro Hada of Mizusawa VLBI Observatory, National Astronomical Observatory of Japan (the principal investigator on the 86 GHz observation in Figure 1) and Martin Hardacastle of Centre for Astrophysics Research, School of m Physics, Astronomy and Mathematics, University of Hertfordshire in order to study this lack of emission of along the spine. In the paper “A New Solution to the Plasma Starved Event Horizon Magnetosphere: Application to the Forked Jet in M87” published in Astronomy and Astrophysics in 2018 the authors provide an explanation of the physics that does not allow the event the event horizon magnetosphere to launch a powerful jet in M87, thereby producing the weak flux emission along the spine above the event horizon evident in Figure 1. In summary, for low luminosity AGN, such as M87, it is shown that accreted large scale poloidal magnetic flux is dissipated when it approaches the event horizon and no significant magnetosphere can be obtained.

Figure 1. The 3.5 mm, global VLBI, image of Hada et al. (2016) with the EHT detected core at 1.3 mm from Akiyama et al. (2016) and Doeleman et al. (2012) overlaid. Note the extreme absence of emission along the central spine within 50 M of the black hole (the limit of the resolution of the radio image)

Publications (in last 3 years)

Punsly, Brian; A Jet Source of Event Horizon Telescope Correlated Flux in M87, ApJ 850, 190 (2017)

Punsly, Brian;, Kharb, Preeti The kinetically dominated quasar 3C 418, MNRAS Lett. 468 72 (2017)

Reynolds, Cormac; Punsly, Brian; Miniutti, Giovanni; O'Dea, Christopher P.; Hurley-Walker, Natasha., The Relativistic Jet-accretion Flow-Wind Connection in Mrk 231, ApJ 836 155 (2017)

Punsly, B.; Hardcastle, M.; Hada, K. A new solution to the plasma starved event horizon magnetosphere. Application to the forked jet in M87, 2018, A & A, 614, 104

Punsly, Brian; Marziani, Paola; Bennert, Vardha N.; Nagai, Hiroshi; Gurwell, Mark A, Revealing the Broad Line Region of NGC 1275: The Relationship to Jet Power, 2018, ApJ, 869, 143

Punsly, Brian; Tramacere, Andrea; Kharb, Preeti; Marziani, Paola, The Powerful Jet and Gamma-Ray Flare of the Quasar PKS 0438-436, 2018, ApJ, 869, 174

Punsly, B. Discrete and Continuous Ejection Models of the Radio Source Associated with GW170817 2019 ApJL 871 34

Punsly, B. Constraints on Black Hole Jet Models Used As Diagnostic Tools of Event Horizon Telescope Observations of M87 2019 ApJL 879 11