On the Persistence of QPOs during the SGR 1806-20 Giant Flare

Author(s)

Miller, M. Coleman ^{[1, 2]} ; Chirenti, Cecilia ^[3] ; Strohmayer, Tod E. ^{[4, 5]}

Affiliation

^[1] Univ Maryland, Dept Astron, College Pk, MD 20742 - USA

^[2] Univ Maryland, Joint Space Sci Inst, College Pk, MD 20742 - USA

^[3] Univ Fed ABC, Ctr Matemat Computacao & Cognicao, BR-09210170 Santo Andre, SP - Brazil

^[4] NASA, Astrophys Sci Div, Goddard Space Flight Ctr, Greenbelt, MD 20771 - USA

^[5] NASA, Joint Space Sci Inst, Goddard Space Flight Ctr, Greenbelt, MD 20771 - USA

• Document type: Journal article
• Source: ASTROPHYSICAL JOURNAL; v. 871, n. 1 JAN 20 2019.
• Web of Science Citations: 3

Abstract

The discovery of quasi-periodic brightness oscillations (QPOs) in the X-ray emission accompanying the giant flares of the soft gamma-ray repeaters SGR 1806-20 and SGR 1900+14 has led to intense speculation about their nature and what they might reveal about the interiors of neutron stars. Here we take a fresh look at the giant flare data for SGR 1806-20, and in particular we analyze short segments of the post-peak emission using a Bayesian procedure, which has not previously been applied to these data. We find at best weak evidence that any QPO persists for more than similar to 1 s; instead, almost all the data are consistent with a picture in which there are numerous independently excited modes that decay within a few tenths of a second. This has interesting implications for the rapidity of decay of the QPO modes, which could occur by the previously suggested mechanism of coupling to the MHD continuum. The strongest QPOs favor certain rotational phases, which might suggest special regions of the crust or of the magnetosphere. We also find several previously unreported QPOs in these data, which may help in tracking down their origin. (AU)

• FAPESP's process: 15/50421-8 - Gravitational waves and neutron star oscillations
• Grantee: Cecilia Bertoni Martha Hadler Chirenti
• Support type: Regular Research Grants