Image of the Day: Pulsar in Supernova Remnant Sets Speed Record at 6 Million MPH

 

          

 

NASA's Chandra X-ray Observatory and ESA's XMM-Newton in space, and the Parkes radio telescope in Australia -- may have found the fastest moving pulsar ever seen. The evidence for this potentially record-breaking speed comes, in part, from the features highlighted in the composite image below. X-ray observations from Chandra (green) and XMM-Newton (purple) have been combined with infrared data from the 2MASS project and optical data from the Digitized Sky Survey (colored red, green and blue, but appearing in the image as white).

The large area of diffuse X-rays seen by XMM-Newton was produced when a massive star exploded as a supernova, leaving behind a debris field, or supernova remnant known as SNR MSH 11-16A (image at top of page). Shocks waves from the supernova have heated surrounding gas to several million degrees Kelvin, causing the remnant to glow brightly in X-rays.* The Chandra image shown in the inset ("X-ray close-up") reveals a comet-shaped X-ray source well outside the boundary of the supernova remnant. This source consists of a point-like object with a long tail trailing behind it for about 3 light years. The bright star nearby and also the one in SNR MSH11-16A are both likely to be foreground stars unrelated to the supernova remnant.

The point-like X-ray source was discovered by the International Gamma-Ray Astrophysics Laboratory, or INTEGRAL, and is called IGR J11014-6103 (or IGR J11014 for short). It may be a rapidly spinning, super-dense star --a "pulsar", a type of neutron star-- that was ejected during the explosion. If so, it is racing away from the center of the supernova remnant at millions of miles per hour.

The favored interpretation for the tail of X-ray emission is that a pulsar wind nebula, that is, a "wind" of high-energy particles produced by the pulsar, has been swept behind a bow shock created by the pulsar's high speed. (A similar case was seen in another object known as PSR B1957+20.

The elongated emission is pointing towards the center of MSH 11-61A where the pulsar would have been formed, supporting the idea that the Chandra image is of a pulsar wind nebula and its bow shock. Another interesting feature of the Chandra image, also seen with XMM-Newton, is the faint X-ray tail extending to the top-right. The cause of this feature is unknown, but similar tails have been seen from other pulsars that also do not line up with the pulsar's direction of motion.

Based on earlier observations, astronomers estimate that the age of MSH 11-61A is approximately 15,000 years, and it lies at a distance of about 30,000 light years away from Earth. Combining these values with the distance that the pulsar has appeared to have traveled from the center of the MSH 11-61A, astronomers estimate that IGR J11014 is moving at a speed between 5.4 million and 6.5 million miles per hour.

The only other neutron star associated with a supernova remnant that may rival this in speed is the candidate found in the supernova remnant known as G350.1-0.3. The speed of the neutron star candidate in this system is estimated to lie between 3 and 6 million miles per hour.

The high speeds estimated for both IGR J11014 and the neutron star candidate in G350.1-0.3 are preliminary and need to be confirmed. If they are confirmed, explaining the high speeds of the neutron star presents a severe challenge to existing models for supernova explosions.

One important caveat in the conclusion that IGR J11014 may be the fastest moving pulsar is that pulsations have not been detected in it during a search with the Commonwealth Scientific and Industrial Research Organization (CSIRO) Parkes radio telescope. This non-detection is not surprising for a pulsar located about 30,000 light years away.

However, there are other pieces of evidence that support the pulsar interpretation. First, the lack of detection of a counterpart to the X-ray source in optical or infrared images supports the idea that it is a pulsar, since such objects are very faint at these wavelengths. Also, there are no apparent differences in the brightness of the source between XMM-Newton observations in 2003 and the Chandra observations in 2011, behavior that is expected if IGR J11014 is a pulsar. Finally, the X-ray spectrum of the source, that is, its signature in energy, is similar to what astronomers expect to see for a pulsar.

 

                  

The Daily Galaxy via Chandra X-Ray Observatory

Image Credit: X-ray: NASA/CXC/UC Berkeley/J. Tomsick et al and ESA/XMM-Newton; Optical: DSS, 2MASS/UMass/IPAC-Caltech/NASA/NSF

Comments

[Harry]

6 Million miles per hour? It would be useful to also indicate what it is in KM/Hour. The rest of the world uses metrics, time for the backward US to get with the program.

[PP]

Use the metric system like most of the world instead of measurement units from the time of Charlemagne.

[notHarryorPP]

Hmmmm, I wonder how many space ships your little countrys have launched to the moon? To the heliosphere? To most of the planets in our solar system? Or maybe even just into space?? Backwards?? If you say so as you get your asses kicked in technology, farming, industry and every other category. Except whining.

Also, you can google the conversion easier than complaining about other things you have 0 control over.

[Tosca Zraikat]

Obviously no one has anything to say about this article, just about each other. Pity. Whoever is out there must shake their heads over human pettiness.

[Matt Rhodes]

Amazing. To think of how matter behaves at such incredible speeds - understanding how the remnants of stars and their mass effects the cosmic environment around them!

[Josh Tao]

Such a deep image folks, loving that.