Closer view of the IGR J11014-6103 outflows

Abstract

IGR J11014-6103 (also known as the Lighthouse Nebula) is composed of a bow-shock pulsar wind nebula (PWN) and large-scale X-ray jet-like features, all powered by PSR J1101-6101. Previous observations suggest that the jet features stem from a ballistic jet of relativistic particles. In order to confirm the nature of the jet and the counter-jet, we obtained a new deep 250 ks Chandra observation of the Lighthouse Nebula. We performed detailed spatial and spectral analysis of all X-ray components of the system. The X-ray PWN is now better resolved and shows a peculiar morphology resembling the shape of an arrow. The overall helical pattern of the main jet is confirmed. However, there are large deviations from a simple helical model at small and large scales. Significant extended emission is now detected, encompassing the main jet all along its length. The presence of an apparent gap along the main jet at ∼50 distance from the pulsar is confirmed; however, the surrounding extended emission prevents conclusions on the coherence at this position of the jet. The counter-jet is now detected at high statistical significance. In addition, we found two small-scale arcs departing from the pulsar towards the jets. We also looked for possible bow-shock emission due to the pulsar motion, with a short VLT/FORS2 H-α observation. No clear emission is found, most likely because of the contamination from a diffuse nebulosity. The results of our X-ray analysis show that both a ballistic jet scenario and an alternative scenario involving the diffusion of particles along pre-existing interstellar magnetic field lines are able to satisfactorily explain some of the observational evidence, but cannot fully reproduce the observations.

Deep Chandra Observations of the Pulsar Wind Nebula Created by PSR B0355+54

“…As the whiskers do not appear to be bent back by the ram pressure, they are likely ambient ISM structures illuminated by pulsar-produced particles. This scenario received support in the recent study of the Lighthouse PWN (Pavan et al 2016) where evidence of draping of the ISM magnetic field lines around the bow shock head (Lyutikov 2006;Dursi & Pfrommer 2008) is seen in the Chandra ACIS image. If the r s < r g requirement is indeed a necessary condition for the leakage, it provides an additional link between pulsar and PWN properties, and decouples the ultra-relativistic electron energies from the often poorly constrained PWN magnetic field.…”

“…On the other hand, much more pronounced spectral softening trends have been measured in the N157B (∆Γ ≈ 1.3, Chen et al 2006), the Lighthouse (∆Γ ≈ 0.7, Pavan et al 2016), and the Mouse (Gaensler et al 2004; ∆Γ ≈ 1.5, Klingler et al in prep) PWNe.…”

Chandra Observations of Outflows From PSR J1509–5850

“…The former shows a particularly remarkable structure. The deep 300 ks Chandra ACIS image of the Lighthouse Nebula shown in Figure 15 reveals a long (∼11 pc) jet-like outflow that originates near the pulsar, bends back in the direction opposite to that of the pulsars' proper motion, and then sharply turns in a direction nearly orthogonal to the proper motion direction (see also Pavan et al 2015). This outflow can possibly be interpreted in the framework of the Bandiera (2008) scenario, similar to the Guitar and J1509 misaligned outflows.…”

“…Some examples of such outflows are the pulsar wind nebulae (PWNe) associated with PSRs B0355+54 (McGowan et al 2006), J0357-3205 (De Luca et al 2011), and J1741-2054 (Auchettl et al 2015). Moreover, there has been growing evidence that PWNe around high-speed pulsars (such as PSR B2224+65, IGR J11014-6103) exhibit puzzling elongated features in addition to cometary tails (Hui & Becker 2007;Pavan et al 2014Pavan et al , 2015. To understand the origin of the diverse morphologies of pulsar outflows and their interaction with the ambient medium, deep X-ray observations with high spatial resolution are particularly valuable.…”

XMM–Newton observations of a gamma-ray pulsar J0633+0632: pulsations, cooling and large-scale emission

“…Its orientation, almost transverse to the presumed pulsar proper motion, allows us to suggest that the feature may be an outflow misaligned from the pulsar as seen, for example, in the Lighthouse nebula (see e.g. Pavan et al 2016). Alternatively, it can be explained in the same way as emission in regions 3-4, and that seems like a more favourable explanation because of a remarkable spatial coincidence between the X-ray emission seen in region 2 and the clump material revealed in various spectral bands, as it can be guessed from Fig.…”