Systematic study of magnetar outbursts Francesco Coti Zelati Institute for Space Sciences, CSIC-IEEC, Barcelona In collaboration with N. Rea (CSIC-IEEC, U. Amsterdam), J. A. Pons (U. Alicante), S. Campana (INAF-OAB), P. Esposito (U. Amsterdam) Coti Zelati et al., submitted Physics of Neutron Stars 2017, Ioffe Institute, Saint Petersburg, July 10, 2017
Observational properties Swift-XRT INTEGRAL COMPTEL About 25 X-ray pulsars with Lx ~ 10 33-10 36 erg s -1 Fermi-LAT X-ray luminosity generally larger than the rotational energy loss rate soft and hard X-ray emission (0.5-200 kev); thermal + PL spectrum 4U 0142+614 Kuiper et al. 2004; Abdo et al. 2010 rotating with P ~ 2-12 s magnetic fields of ~10 13-10 15 Gauss flaring activity in soft gamma-rays (0.01-10 2 s; Lx ~10 39-10 47 erg s -1 ) faint infrared/optical emission (Israel et al. 2010) Kaspi et al. 2003 transient pulsed radio emission (in 4 cases) see Rea & Esposito (2011); Turolla et al. (2015); Kaspi & Beloborodov (2017) for reviews Camilo et al. 2006
Magnetar flaring activity (timescale: seconds/minutes) Short bursts duration ~0.01-1s Lx ~10 39-10 41 erg s -1 soft γ-rays thermal spectra (kt ~ 30-40 kev) Intermediate bursts duration 1-40 s peak ~10 41-10 43 erg s -1 abrupt on-set usually soft γ-rays thermal spectra Giant Flares very rare events (only 3 observed) Lx > 3x10 44 erg s -1 initial peak lasting <1 s with a hard spectrum ringing tail that can last > 500s, with softer spectrum and showing the NS spin pulsations Kaspi et al. 2003 Israel et al. 2008 Israel et al. 2008 (Palmer et al. 2005) Palmer et al. 2005
Magnetar outburst activity (timescale: months/years) 1000 100 Bolometric luminosity (10 33 erg s 1 ) 10 1 0.1 SGR 1627 41 (1998) 1E 2259+586 (2002) SGR 1806 20 CXOU 1647 4552 (2006) SGR 1627 41 (2008) SGR 0501+4516 1E 1547 5408 (2008) 1E 1547 5408 (2009) SGR 0418+5729 SGR 1833 0832 Swift J1822.3 1606 Swift J1834.9 0846 CXOU 1647 4552 (2011) 1E 1048.1 5937 (2011) 1E 2259+586 (2012) SGR 1745 2900 SGR 1935+2154 1E 1048.1 5937 (2016) 0.01 0.01 0.1 1 10 100 1000 Time (days since outburst onset) Coti Zelati et al. submitted
Outburst mechanisms 1. Internal source of heat: Local magnetic stresses deform part of the stellar crust. Plastic flows convert the magnetic energy into heat. Partly is conducted up to the surface and radiated (thermal afterglow) 2. External source of heat: Crustal displacements twist up the external B-field. Returning currents hit and heat the NS surface. The bundle dissipates as the energy supply from the star interior decreases. Both processes are likely at work. Emission can be sustained up to a few years. Thompson et al. 2002; Beloborodov 2009; Pons & Rea 2012; Parfrey et al. 2013; Beloborodov & Levin 2014 Beloborodov & Li 2016; Li et al. 2016
Motivation for the study A systematic and homogeneous analysis of the spectral properties of magnetars in outbursts is needed to: (i) model all outbursts cooling curves in a consistent way; (ii) unveil possible correlations among different parameters Deeper insight into the emission processes via modelling with internal crustal cooling codes. Varying the injected energy Pons & Rea 2012 Pons & Rea 2012 Varying the quiescent luminosity
Systematic study magnetar outbursts: some numbers The magnetar outburst online catalog - 23 outbursts - 14 magnetars + 2 high-b RPPs + CCO in RCW 103 - about 1100 X-ray observations (12 Ms) between 1998 and mid May 2017
Systematic study magnetar outbursts: data analysis The magnetar outburst online catalog - reduction of raw data sets, extraction of spectra for all observations - spectral fitting with BB, 2BB, BB+PL and more physically-motivated models - extraction of fluxes and luminosities in each observation - extraction of the light curves - empirical modelling of the bolometric cooling curves - estimate of the outburst energetics and decay-timescale
High quality X-ray spectra 1E 1547-5408 (2008) 1E 1547-5408 (2009) Chandra Chandra SGR 0418+5729 SGR 1833-0832 XMM-Newton XMM-Newton Swift 1822.3-1606 Swift 1834.9-0846 XMM-Newton Chandra
Cooling curves: XTE J1810-197 Absorbed X-ray flux BB1 X-ray luminosity Bolometric BB2 X-ray luminosity X-ray luminosity
The outburst sample, fitted models, energetics and timescales Bolometric luminosity (10 33 erg s -1 ) SGR 1627-41 (1998) 1E 2259+586 (2002) SGR 1806-20 CXOU 1647-4552 (2006) SGR 1627-41 (2008) SGR 0501+4516 - - - 1E 1547-5408 (2008) 1E 1547-5408 (2009) SGR 0418+5729 SGR 1833-0832 Swift 1822.3-1606 - - - Swift J1834.9-0846 - - - CXOU 1647-4552 (2011) - - - 1E 1048.1-5937 (2011) -. - 1E 2259+586 (2012) - - - SGR 1745-2900 - - - 1E 1048.1-5937 (2016) Time (days since outburst onset)
Correlations & Anticorrelations
Correlations & Anticorrelations SGR 0418+5729 5.7 σ Swift J1834.9-0846 PSR J1119-6127 Swift 1822.3-1606 SGR 1627-41 (2008) 1E 1547-5408 (2009) 1E 161348-5055 (2000) 1E 1547-5408 (2008) 1E 161348-5055 (2016) SGR 1745-2900 SGR 1627-41 (1998) SGR 0501+4516 CXOU 1647-4552 (2006) PSR J1846-0258 CXOU 1647-4552 (2011) SGR 1833-0832 XTEJ1810-197 1E 1048.1-5937 (2011) SGR 1806-20 1E 1841-045 1E 1048.1-5937 (2016) 4U 0142+614 (2011, 2015) SGR 1900+14 (2001) 1E 2259+586 (2002) SGR 1900+14 (2006) 1E 2259+586 (2012) Pons & Rea 2012 The definition of transient magnetars as opposed to the persistent magnetars is deceptive: it only reflects their different quiescent luminosities 4.0 σ 1E 1547-5408 (2009) SGR 1806-20 SGR 1745-2900 1E 16348-5055 (2016) 1E 1048.1-5937 (2011) Large flux enhancements can only be observed in faint quiescent magnetars 1E 1048.1-5937 (2016) SGR 1627-41 (1998) 1E 16348-5055 (2000) XTEJ1810-197 CXOU 1647-4552 (2006) SGR 1627-41 (2008) SGR 1833-0832 PSR J1119-6127 Swift 1822.3-1606 1E 2259+586 (2012) PSR J1846-0258 Swift J1834.9-0846 SGR 0418+5729 SGR 0501+4516 1E 2259+586 (2002) CXOU 1647-4552 (2011) Pons & Rea 2012
Correlations & Anticorrelations Magnetars CCOs RPPs XDINSs CCOs depart significantly from the trend. 5.3 σ with CCOs Expected in the hidden magnetic field scenario: fallback accretion onto the NS (10-3 - 10-2 MSun in hrs-days) can bury a B field of a few 10 12 G into the inner crust (Viganò & Pons 2012; Torres-Forné et al. 2016). The external B field is lower than the internal hidden B field, hence does not trace the bolometric luminosity Magnetars CCOs RPPs XDINSs RPPs depart a bit from the trend. The larger luminosity wrt the prediction is likely due to slamming particles heating the NS surface, providing an additional source of heat 6.5 σ without CCOs
Correlations & Anticorrelations 3.7 σ 1E 1547-5408 (2009) SGR 1745-2900 1E 1048.1-5937 (2011) 1E 1048.1-5937 (2016) XTEJ1810-197 SGR 1627-41 (1998) CXOU 1647-4552 (2006) SGR 1627-41 (2008) PSR J1119-6127 SGR 1833-0832 SGR 1806-20 Broad agreement with the idea that magnetar outbursts are ultimately powered by the dissipation of the B-field PSR J1846-0258 Swift 1822.3-1606 1E 2259+586 (2012) Swift J1834.9-0846 1E 2259+586 (2002) SGR 0418+5729 SGR 0501+4516 CXOU 1647-4552 (2011) SGR 1806-20 SGR 1745-2900 1E 1547-5408 (2009) 1E 1048.1-5937 (2011) 3.3 σ 1E 1048.1-5937 (2016) XTEJ1810-197 SGR 1627-41 (1998) SGR 1627-41 (2008) CXOU 1647-4552 (2006) SGR 1833-0832 PSR J1119-6127 Young magnetars undergo more energetic outbursts PSR J1846-0258 Swift J1834.9-0846 1E 2259+586 (2012) 1E 2259+586 (2002) Swift 1822.3-1606 SGR 0501+4516 SGR 0418+5729 CXOU 1647-4552 (2011)
Correlations & Anticorrelations 3.9 σ 1E 1547-5408 (2009) SGR 1627-41 (1998) 1E 161348-5055 (2000) Swift 1822.3-1606 SGR 1627-41 (2008) 1E 161348-5055 (2016) XTEJ1810-197 1E 1048.1-5937 (2011) SGR 1806-20 SGR 1745-2900 SGR 0501+4516 1E 2259+586 (2012) CXOU 1647-4552 (2006) 1E 1048.1-5937 (2016) SGR 1833-0832 SGR 0418+5729 PSR J1119-6127 CXOU 1647-4552 (2011) PSR J1846-0258 1E 2259+586 (2002) Swift J1834.9-0846 Similar decay pattern for all magnetar outbursts Expected in the interior crustal cooling model (the deeper the location of the energy release, the more energetic the outburst, the longer the time for heat diffusion) Expected in the untwisting bundle model (Τ E^0.5)
The magnetar outburst online catalog - online catalogues with all files and parameters soon publicly available magnetars.ice.csic.es
The magnetar outburst online catalog - online catalogues with all files and parameters soon publicly available Fit your favourite function to different parameters magnetars.ice.csic.es
The magnetar outburst online catalog - online catalogues with all files and parameters soon publicly available magnetars.ice.csic.es