Division of Atmospheric and Geospace Sciences

ABSTRACT In this paper, we performed magnetohydrodynamics numerical experiments to look into the dynamic behaviour of the current sheet (CS) between the coronal mass ejection (CME) and the associated solar flare, especially the CS oscillation and plasmoid motions in coronal conditions. During the evolution, the disrupting magnetic configuration becomes asymmetric first in the buffer region at the bottom of the CME bubble. The Rayleigh−Taylor instability in the buffer region and the deflected motion of the plasma driven by the termination shock at the bottom of the CME bubble cause the buffer region to oscillate around the y-axis. The local oscillation propagates downwards through the CS, prompting an overall CS oscillation. As the buffer region grows, the oscillation period becomes longer, increasing from about 30 s to about 16 min. Meanwhile, there is another separated oscillation with a period between 0.25 and 1.5 min in the cusp region of the flare generated by velocity shearing. The tearing mode instability yields formations of plasmoids inside the CS. The motions of all the plasmoids observed in the experiment accelerate, which implies that the large-scale CME/flare CS itself in the true eruptive event is filled with the diffusion region according the the standard theory of magnetic reconnection.

ABSTRACT We present a spectroscopic and imaging study of an abnormal active galactic nucleus (AGN), 2MASX J00423991 + 3017515. This AGN is newly identified in the hard X-rays by the Swift BAT All-Sky survey and found in an edge-on disc galaxy interacting with a nearby companion. Here, we analyse the first optical spectra obtained for this system (taken in 2011 and 2016), high-resolution imaging taken with the Hubble Space Telescope and Chandra X-ray Observatory, and 1 imaging with the Very Large Array. Two unique properties are revealed: the peaks of the broad Balmer emission lines (associated with gas orbiting very near the supermassive black hole) are blueshifted from the corresponding narrow line emission and host galaxy absorption by 1540 km s−1, and the AGN is spatially displaced from the apparent centre of its host galaxy by 3.8 kpc. We explore several scenarios to explain these features, along with other anomalies, and propose that 2MASX J00423991 + 3017515 may be an AGN with an unusually strong wind residing in a uniquely configured major merger, or that it is an AGN recoiling from either a gravitational ‘slingshot’ in a three-body interaction or from a kick due to the asymmetric emission of gravitational waves following the coalescence of two progenitor supermassive black holes.

This panel addresses the policies and procedures governments should adopt to ensure that the work performed by outside consultants is in the best interest of the agency. The discussion includes a review of legal and professional standards, including fiduciary roles, conflicts of interest, and codes of ethics of various types of outside professionals, including municipal advisors and auditors. Having appropriate policies and procedures in place when hiring professionals, including thorough due diligence, developing a scope of services, engaging in a request for proposal process, and understanding how fees are assessed, are key takeaways from the panel.

This paper identifies important distinctions among different types of municipal debt, highlighting the difference between general fund securities—backed only by the spending power of the municipalities’ general fund—and general obligation (GO) securities. The author highlights the importance, in evaluating municipal bonds, of considering whether state law permits local governments to file for bankruptcy and whether state law gives general obligation bondholders the protection of a statutory lien if the local governments attempt to fi le under Chapter 9. It will be necessary to monitor the July 2013 Detroit bankruptcy closely to determine the long-term prospects for general obligation bonds not secured by statutory liens in states permitting local bankruptcy.

This panel discusses the dividing line between which professionals are and which are not “municipal advisors” pursuant to SEC Rule 15Ba1-1 and published SEC guidance. Is the line between them well-defined? Where might there be overlap and when should regulators be concerned with the role and work of consultants? What are the regulations that issuers should be aware of as it affects them in working with regulated consultants? Additional detail, based upon excerpts from SEC statements and Rule 15Ba1-1, is set forth in an Appendix. Key resources include SEC Rule 15Ba1-1, SEC Rel. No. 34-70462, 78 FR 67468 (November 12, 2013), and SEC FAQs published at https://www.sec.gov/info/municipal/mun-advisors-faqs.shtml.