X-RAY INVESTIGATION OF THE DIFFUSE EMISSION AROUND PLAUSIBLE γ-RAY EMITTING PULSAR WIND NEBULAE IN KOOKABURRA REGION

I review the results of radio and X-ray searches for pulsations from young neutron stars, emphasizing work accomplished in the last five years. I cover undirected searches, as well as directed searches of pulsar wind nebulae, EGRET γ-ray sources, and also the search for pulsations from “isolated neutron stars” and “central compact objects”.

Download Full-text

The contribution of Galactic TeV pulsar wind nebulae to Fermi-LAT diffuse emission

10.21203/rs.3.rs-539249/v1 ◽

2021 ◽

Author(s):

Vittoria Vecchiotti ◽

Giulia Pagliaroli ◽

Francesco Villante

Keyword(s):

Cosmic Rays ◽

Energy Range ◽

Spectral Index ◽

Large Scale ◽

Galactic Center ◽

Galactic Plane ◽

Diffuse Emission ◽

Pulsar Wind Nebulae ◽

Γ Ray ◽

Pulsar Wind

Abstract The large-scale diffuse γ−ray flux observed by Fermi-LAT in the 1-100 GeV energy range, parameterized as ∝ E−Γ, has a spectral index Γ that depends on the distance from the Galactic center. This feature, if attributed to the diffuse emission produced by cosmic rays (CR) interactions with the interstellar gas, can be interpreted as the evidence of a progressive CR spectral hardening towards the Galactic center. This interpretation challenges the standard cosmic rays diffusion paradigm. We report on the implications of TeV Pulsar Wind Nebulae observed by the HESS Galactic Plane Survey in the 1-100 TeV energy range for the interpretation of Fermi-LAT data. We argue that a relevant fraction of this population cannot be resolved by Fermi-LAT in the GeV domain providing a relevant contribution to the large-scale diffuse emission, viz. the 30% of the total diffuse γ-ray emission in the inner Galaxy. This additional component naturally accounts for a large part of the spectral index variation observed by Fermi-LAT, weakening the evidence of CR spectral hardening in the inner Galaxy.

Download Full-text

Variable high-energy γ-ray emission from pulsar wind nebulae

10.1063/1.1419470 ◽

2001 ◽

Author(s):

Mallory S. E. Roberts

Keyword(s):

High Energy ◽

Pulsar Wind Nebulae ◽

Γ Ray ◽

Pulsar Wind

Download Full-text

Peculiar Differences in Radio and X-ray Synchrotron Radiation from Pulsar Wind Nebulae

Symposium - International Astronomical Union ◽

10.1017/s0074180900181033 ◽

2004 ◽

Vol 218 ◽

pp. 221-224

Author(s):

John R. Dickel ◽

Shiya Wang

Keyword(s):

Synchrotron Radiation ◽

Radio Emission ◽

Supernova Remnants ◽

Crab Nebula ◽

Pulsar Wind Nebulae ◽

X Ray ◽

Pulsar Wind ◽

The Crab Nebula

Several Crab-type supernova remnants appear to have very bright non-thermal X-ray cores just around the pulsar or expected pulsar. This X-ray brightness is often not matched by a corresponding increase in radio emission. The best example of this phenomenon is in N157B in the LMC. G21.5−0.9 and possibly 3C 58 also show it while the Crab Nebula and 0540−69.3 do not. Some method to enhance the higher energy particles must be present in these objects.

Download Full-text

Jet-like structures from PSR J1135–6055

Astronomy and Astrophysics ◽

10.1051/0004-6361/202039327 ◽

2020 ◽

Vol 644 ◽

pp. L4

Author(s):

P. Bordas ◽

X. Zhang

Keyword(s):

High Energy ◽

Bow Shock ◽

Morphological Properties ◽

Physical Origin ◽

Pulsar Wind Nebulae ◽

Jet Formation ◽

X Ray ◽

Pulsar Wind ◽

Alternative Scenarios ◽

High Energy Particles

Pulsar wind nebulae (PWNe) produced from supersonic runaway pulsars can render extended X-ray structures in the form of tails and prominent jets. In this Letter, we report on the analysis of ∼130 ks observations of the PWN around PSR J1135–6055 that were obtained with the Chandra satellite. The system displays bipolar jet-like structures of uncertain origin, a compact nebula around the pulsar likely formed by the bow shock ahead of it, and a trailing tail produced by the pulsar fast proper motion. The spectral and morphological properties of these structures reveal strong similarities with the PWNe in other runaway pulsars, such as PSR J1509–5850 and Geminga. We discuss their physical origin considering both canonical PWN and jet formation models as well as alternative scenarios that can also yield extended jet-like features following the escape of high-energy particles into the ambient magnetic field.

Download Full-text

Revealing hidden variability in PWNe with spectral index maps

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2364 ◽

2020 ◽

Vol 498 (1) ◽

pp. 821-834

Author(s):

Benson T Guest ◽

Samar Safi-Harb

Keyword(s):

Spectral Index ◽

Rotational Energy ◽

Line Of Sight ◽

Pulsar Wind Nebulae ◽

X Ray ◽

Analysis Technique ◽

Intrinsic Motion ◽

Pulsar Wind ◽

Map Analysis ◽

Index Maps

ABSTRACT Pulsar wind nebulae (PWNe) are the synchrotron bubbles inflated by the rotational energy of a neutron star. Observing variability within them has previously been limited to cases of significant brightening, or the few instances where transient features are interpreted in terms of intrinsic motion or associated with variability from the pulsar. Jet and torus morphology are also only visible in cases of differing brightness with respect to the surrounding nebula and favourable alignment with our line of sight. Spectral map analysis involves binning observations with an adaptive algorithm to meet a signal limit and colouring the results based on the desired model parameter fits. Minute changes in spectral index become therefore apparent even in cases where brightness images alone do not suggest any underlying changes. We present a Chandra X-ray study of the PWNe in G21.5–0.9, Kes 75, G54.1+0.3, G11.2–0.3, and 3C 58, using archival observations accumulated over the ∼20-yr lifetime of the mission. With the spectral map analysis technique, we discover evidence for previously unknown variability opening a new window into viewing PWNe.

Download Full-text

Searching for X-ray counterparts of Fermi Gamma-ray pulsars in Suzaku observations

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312013130 ◽

2011 ◽

Vol 7 (S279) ◽

pp. 317-318 ◽

Cited By ~ 1

Author(s):

Yu Aoki ◽

Takahiro Enomoto ◽

Yoichi Yatsu ◽

Nobuyuki Kawai ◽

Takeshi Nakamori ◽

...

Keyword(s):

Gamma Ray ◽

Thermal Emission ◽

Flux Ratio ◽

Radio Pulsars ◽

Pulsar Wind Nebulae ◽

X Ray ◽

Absorbed Power ◽

Pulsar Wind ◽

Error Circle

AbstractWe report the Suzaku follow-up observations of the Gamma-ray pulsars, 1FGL J0614,13328, J1044.55737, J1741.82101, and J1813.31246, which were discovered by the Fermi Gamma-ray observatory. Analysing Suzaku/XIS data, we detected X-ray counterparts of these pulsars in the Fermi error circle and interpreted their spectra with absorbed power-law functions. These results indicate that the origin of these X-ray sources is non-thermal emission from the pulsars or from Pulsar Wind Nebulae (PWNe) surrounding them. Moreover we found that J1741.82101 exhibits a peculiar profile: spin-down luminosity vs flux ratio between X- and gamma-rays is unusually large compared to usual radio pulsars.

Download Full-text

Pulsar Wind Nebulae and the X‐Ray Emission of Nonaccreting Neutron Stars

The Astrophysical Journal ◽

10.1086/425295 ◽

2004 ◽

Vol 617 (1) ◽

pp. 480-489 ◽

Cited By ~ 44

Author(s):

K. S. Cheng ◽

Ronald E. Taam ◽

W. Wang

Keyword(s):

Neutron Stars ◽

Pulsar Wind Nebulae ◽

X Ray ◽

Pulsar Wind

Download Full-text

PULSAR WIND NEBULAE MODELING

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194514601628 ◽

2014 ◽

Vol 28 ◽

pp. 1460162 ◽

Cited By ~ 7

Author(s):

NICCOLÒ BUCCIANTINI

Keyword(s):

High Resolution ◽

High Energy ◽

Clear Understanding ◽

Strong Impact ◽

Pulsar Magnetosphere ◽

Pulsar Wind Nebulae ◽

X Ray ◽

X Ray Imaging ◽

Dynamical Properties ◽

Pulsar Wind

Pulsar Wind Nebulae (PWNe) are ideal astrophysical laboratories where high energy relativistic phenomena can be investigated. They are close, well resolved in our observations, and the knowledge derived in their study has a strong impact in many other fields, from AGNs to GRBs. Yet there are still unresolved issues, that prevent us from a full clear understanding of these objects. The lucky combination of high resolution X-ray imaging and numerical codes to handle the outflow and dynamical properties of relativistic MHD, has opened a new avenue of investigation that has lead to interesting progresses in the last years. Despite all of this, we do not understand yet how particles are accelerated, and the functioning of the pulsar wind and pulsar magnetosphere, that power PWNe. I will review what is now commonly known as the MHD paradigm, and in particular I will focus on various approaches that have been and are currently used to model these systems. For each I will highlight its advantages, limitations, and degree of applicability.

Download Full-text

Radio study of the extended TeV source VER J1907+062

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz3414 ◽

2019 ◽

Vol 491 (4) ◽

pp. 5732-5739

Author(s):

L Duvidovich ◽

A Petriella ◽

E Giacani

Keyword(s):

Atomic Hydrogen ◽

Molecular Clouds ◽

Supernova Remnant ◽

Molecular Gas ◽

Radio Observations ◽

Very Large Array ◽

X Ray ◽

New Radio ◽

Γ Ray ◽

Pulsar Wind

ABSTRACT This paper aims to provide new insights on the origin of the TeV source VER J1907+062 through new high-quality radio observations. We used the Karl G. Jansky Very Large Array (VLA) to observe the whole extension of VER J1907+062 at 1.5 GHz with a mosaicking technique and the PSR J1907+0602 in a single pointing at 6 GHz. These data were used together with 12CO and atomic hydrogen observations obtained from public surveys to investigate the interstellar medium in the direction of VER J1907+062. The new radio observations do not show any evidence of a pulsar wind nebula (PWN) driven by the pulsars present in the field and no radio counterpart to the proposed X-ray PWN powered by PSR J1907+0602 is seen in the new VLA image at 6 GHz down to a noise level of 10 $\mu$Jy beam−1. Molecular clouds were discovered over the eastern, southern, and western borders of the radio shell of G40.5−0.5, suggesting an association with this supernova remnant. We explored several scenarios for the origin of VER J1907+062. We propose as the most probable scenario one in which the TeV emission is produced by two separated γ-ray sources located at different distances: one of leptonic origin and associated with a PWN powered by PSR J1907+0602 at ∼3.2 kpc and another of hadronic origin and produced by the interaction between G40.5−0.5 and the surrounding molecular gas at ∼8.7 kpc.

Download Full-text