Chandra monitoring of the Galactic Centre magnetar SGR J1745-2900 during the initial 3.5 years of outburst decay
Date Issued
2017
Author(s)
Coti Zelati, F.
•
Rea, N.
•
Turolla, R.
•
Pons, J. A.
•
•
Esposito, P.
•
•
•
Zane, S.
•
Tiengo, A.
•
•
•
Baganoff, F. K.
•
Haggard, D.
•
•
Torres, D. F.
•
Borghese, A.
•
Elfritz, J.
Abstract
We report on 3.5 yr of Chandra monitoring of the Galactic Centre magnetar SGR J1745-2900 since its outburst onset in 2013 April. The magnetar spin-down has shown at least two episodes of period derivative increases so far, and it has slowed down regularly in the past year or so. We observed a slightly increasing trend in the time evolution of the pulsed fraction, up to ∼55 per cent in the most recent observations. SGR J1745-2900 has not reached the quiescent level yet, and so far the overall outburst evolution can be interpreted in terms of a cooling hot region on the star surface. We discuss possible scenarios, showing in particular how the presence of a shrinking hotspot in this source is hardly reconcilable with internal crustal cooling and favours the untwisting bundle model for this outburst. Moreover, we also show how the emission from a single uniform hotspot is incompatible with the observed pulsed fraction evolution for any pair of viewing angles, suggesting an anisotropic emission pattern.
Volume
471
Issue
2
Start page
1819
Issn Identifier
0035-8711
Ads BibCode
2017MNRAS.471.1819C
Rights
open.access
File(s)![Thumbnail Image]()
Loading...
Name
2017-CotiZelati-stx1700.pdf
Description
Pdf editoriale
Size
858.69 KB
Format
Adobe PDF
Checksum (MD5)
a5acdc563d1ed11b519f49b43565db0b