Serendipitous Discovery of An Infrared Bow Shock Near PSR J1549-4848 with Spitzer

Abstract

We report on the discovery of an infrared cometary nebula around PSR J1549$-$4848 in our Spitzer survey of a few middle-aged radio pulsars. Following the discovery, multi-wavelength imaging and spectroscopic observations of the nebula were carried out. We detected the nebula in Spitzer IRAC 8.0, MIPS 24 and 70 $\mu$m imaging and in Spitzer IRS 7.5--14.4 $\mu$m spectroscopic observations, and also in the WISE all-sky survey at 12 and 22 $\mu$m.These data were analyzed in detail, and we find that the nebula can be described with a standard bow-shock shape, and that its spectrum contains polycyclic aromatic hydrocarbon and H${}_2$ emission features. However, it is not certain which object drives the nebula. We analyze the field stars and conclude that none of them can be the associated object because stars with a strong wind or mass ejection that usually produce bow shocks are much brighter than the field stars. The pulsar is approximately 15\arcsec\ away from the region in which the associated object is expected to be located. In order to resolve the discrepancy, we suggest that a highly collimated wind could be emitted from the pulsar and produce the bow shock. X-ray imaging to detect the interaction of the wind with the ambient medium and high-spatial resolution radio imaging to determine the proper motion of the pulsar should be carried out, which will help verify the association of the pulsar with the bow shock nebula.

9 pages, 5 figures, accepted for publication in ApJ

References in corpus (6)

• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• Dust Masses, PAH Abundances, and Starlight Intensities in the SINGS Galaxy Sample
• A far-infrared survey of bow shocks and detached shells around AGB stars and red supergiants
• E-BOSS: an Extensive stellar BOw Shock Survey. I: Methods and First Catalogue
• Three-dimensional hydrodynamic simulations of asymmetric pulsar wind bow shocks
• Observations of X-rays and Thermal Dust Emission from the Supernova Remnant Kes 75

Cited by in corpus (12)

• A comprehensive search for stellar bowshock nebulae in the Milky Way: a catalog of 709 mid-infrared selected candidates
• Using 3D Voronoi grids in radiative transfer simulations
• On the origin of jet-like features in bow shock pulsar wind nebulae
• Full-3D relativistic MHD simulations of Bow Shock Pulsar Wind Nebulae: dynamics
• Infrared Photometric Properties of 709 Candidate Stellar Bowshock Nebulae
• Full-3D relativistic MHD simulations of bow shock pulsar wind nebulae: emission and polarization
• Discovery of extended infrared emission around the neutron star RX J0806.4-4123
• A Laminar Model for the Magnetic Field Structure in Bow-Shock Pulsar Wind Nebulae
• Searching for Debris Disks around Seven Radio Pulsars
• 3D Relativistic MHD Simulations of Pulsar Bow Shock Nebulae
• Pulsar Wind Nebulae
• Kinematics of the Central Stars Powering Bowshock Nebulae and the Large Multiplicity Fraction of Runaway OB Stars