Building on the Work of THEMIS


The MMS mission will expand on the work of the previous THEMIS missions. The four satellites will fly in formation and be able to maintain their alignment with respect to each other by using GPS and sharing their location data with each other. Before I moved on to work on the ASTRO-H mission, I worked on the development of the prototype GPS receivers and other navigation radios for MMS.

Video Credit: NASA

NGC 986


A spiral in a furnaceNGC 986 is found in the constellation of Fornax (The Furnace), located in the southern sky. NGC 986 is around 56 million light-years away, and its golden center and barred swirling arms are clearly visible in this image assembled from data captured by Hubble’s Wide Field and Planetary Camera 2. (The stars in the upper right appear a little fuzzy because a gap in the Hubble data was filled in with images from ground-based telescopes. The view  is accurate, but the resolution is no match for Hubble.)

Barred spiral galaxies are spiral galaxies with stars forming a central bar-shaped structure. NGC 986 has the characteristic S-shaped structure of this type of galaxy. Young blue stars can be seen dotted through the galaxy’s arms, and the core is also alight with star formation.

Image Credit: NASA / ESA

Happy Anniversary, Swift


Ten years ago yesterday, a Delta rocket from Cape Canaveral launched the Swift satellite into orbit. From time to time, I’ve published pictures and videos based on data taken by Swift. Most of it has been related to X-ray astronomy because the instrument that I worked on is an X-ray instrument.

M101_Swift_UVSwift has also been doing excellent UV astronomy as well. The picture on the left is the first light UV image from ten years ago. It’s M101, the Pinwheel Galaxy.

Swift‘s UV Optical Telescope has been used to create the most detailed ultraviolet light surveys ever of the Large and Small Magellanic Clouds, the two closest major galaxies. Nearly a million ultraviolet sources appear in the mosaic of the Large Magellanic Cloud below. It was assembled from 2,200 images taken by the UVOT. The 160-megapixel image (drastically reduced resolution here!) required a cumulative exposure of 5.4 days. The image includes light from 160 to 330 nm. Those UV wavelengths are largely blocked by Earth’s atmosphere. The Large Magellanic Cloud is about 14,000 light-years across.lmc_swift

Image Credits: NASA

An Odd Light Source


sdssj133_over_timeAn unusual source of light has been found in a galaxy some 90 million light-years away. The object’s odd properties make it a good match for a supermassive black hole ejected from its home galaxy after merging with another giant black hole, or the source, called SDSS1133, might be the remnant of a massive star that erupted for a record period of time before destroying itself in a supernova explosion. Whether it’s a rogue supermassive black hole or the closing act of a rare star, SDSS1133 has been a persistent source for more than 60 years. This sequence of archival astronomical imagery, taken through different instruments and filters, shows that the source is detectable in 1950 and brightest in 2001.

One possible explanation for this source is a very unusual type of star known as a Luminous Blue Variable (LBV). These massive stars undergo episodic eruptions that through off large amounts of matter into space long before they explode. If this be the case, SDSS1133 would have displayed the longest period of LBV eruptions ever observed.

The object could also be a supermassive black hole ejected from its home galaxy after merging with another giant black hole. The collision merger of two galaxies disrupts their shapes and results in new episodes of star formation. If each galaxy possesses a central supermassive black hole, the two black holes will form a bound binary pair at the center of the merged galaxy before ultimately coalescing themselves. The kick may be strong enough to hurl the merged black hole entirely out of its home galaxy, drifting as a rogue through intergalactic space. More likely, it will go into an elongated orbit around the galaxy, retaining the hot gas trapped around it which will continue to shine until all of it is consumed.

This simulation zooms into galaxy Markarian 177 and object SDSS1133 and suggests how they compare with a simulated galaxy collision. When the central black holes in these galaxies combine, a “kick” launches the merged black hole on a wide orbit taking it far from the galaxy’s core.

Animated GIF Credit: NASA / M. Koss (ETH Zurich)
Video Credit: NASA

Following the Bouncing Lander


OSIRIS_spots_PhilaeThis mosaic was assembled from a series of images captured by Rosetta’s OSIRIS camera taken over the half-hour spanning the first touchdown of the Philae lander Comet 67P/CG. The time of each of image is marked on the corresponding insets and is in UTC. A comparison of the touchdown area shortly before and after first contact with the surface is shown at the top.

The images were taken with the OSIRIS narrow-angle camera when the spacecraft was 17.5 km from the comet centre, or roughly 15.5 km from the surface. The enlarged insets cover a 17 x 17 m area.

From left to right, the images show Philae descending towards and across the comet before touchdown. The image taken after touchdown, at 15:43 GMT, confirms that the lander was moving east at a speed of about 0.5 m/s as it bounced across the surface of the comet.

Philae‘s actual final landing spot still hasn’t been found. After touching down and bouncing again at 17:25 UTC, it finally landed at 17:32. The mission imaging team believes that by combining the CONSERT ranging data with OSIRIS and navcam images from the orbiter and images from near the surface with data from Philae’s ROLIS and CIVA cameras they will be able to determine the lander’s whereabouts.

Image Credit: ESA