How to stumble into a PhD project, and how it can follow you

Teddy Cheung
Teddy Cheung, Credit: Craig Walker

We are delighted to welcome Teddy Cheung, from the National Academy of Sciences, and resident at the Naval Research Laboratory in Washington DC, to give a guest blog post today. Teddy is first author of a paper describing the discovery of the most distant X-ray jet detected to date. Here, he explains some of the background story behind this discovery.

When I started graduate school in 1999 at Brandeis University, exciting discoveries were being made down the road in Cambridge, Massachusetts, with the then newly launched Chandra X-ray Observatory. The first Chandra image unexpectedly revealed a bright X-ray jet from a distant quasar ( and the research groups at SAO and MIT were puzzling over it. But it took me leaving Boston to find my eventual connection.

I spent the summer of 2000 at the Space Telescope Science Institute in Baltimore, Maryland, wanting to learn something entirely new and took on a project in Meg Urry's group studying the galaxies of BL Lac objects (a type of cousin to the quasars) using ground-based near-infrared data. Coincidentally, I shared an office with another graduate student working with Dr. Urry for the summer, Fabrizio Tavecchio from Italy, and they were at that time puzzling over the same Chandra jet detection. Little did I appreciate at the time, that this visit to Baltimore would lead back to my eventual PhD project at Brandeis on the Chandra quasar jets.

Record-Setting X-ray Jet Discovered

GB 1428+4217

This composite image shows the most distant X-ray jet ever observed. X-ray data from NASA's Chandra X-ray Observatory are shown in blue, radio data from the NSF's Very Large Array are shown in purple and optical data from NASA's Hubble Space Telescope are shown in yellow. The jet was produced by a quasar named GB 1428+4217, or GB 1428 for short, and is located 12.4 billion light years from Earth. Labels for the quasar and jet can be seen by mousing over the image. The shape of the jet is very similar in the X-ray and radio data.

X-rays from a Reborn Planetary Nebula

Abell 30

These images of the planetary nebula Abell 30, (a.k.a. A30), show one of the clearest views ever obtained of a special phase of evolution for these objects. The inset image on the right is a close-up view of A30 showing X-ray data from NASA's Chandra X-ray Observatory in purple and Hubble Space Telescope (HST) data showing optical emission from oxygen ions in orange. On the left is a larger view showing optical and X-ray data from the Kitt Peak National Observatory and ESA's XMM-Newton, respectively. In this image the optical data show emission from oxygen (orange) and hydrogen (green and blue), and X-ray emission is colored purple.

A planetary nebula - so called because it looks like a planet when viewed with a small telescope - is formed in the late stage of the evolution of a sun-like star.

Probing a Nearby Stellar Cradle

Cygnus OB2

The Milky Way and other galaxies in the universe harbor many young star clusters and associations that each contain hundreds to thousands of hot, massive, young stars known as O and B stars. The star cluster Cygnus OB2 contains more than 60 O-type stars and about a thousand B-type stars. At a relatively nearby distance to Earth of about 5,000 light years, Cygnus OB2 is the closest massive cluster. Deep observations with NASA's Chandra X-ray Observatory of Cygnus OB2 have been used to detect the X-ray emission from the hot outer atmospheres, or coronas, of young stars in the cluster and to probe how these great star factories form and evolve. About 1,700 X-ray sources were detected, including about 1,450 thought to be stars in the cluster. In this image, X-rays from Chandra (blue) have been combined with infrared data from NASA's Spitzer Space Telescope (red) and optical data from the Isaac Newton Telescope (orange).

Thanks for Everything, Atlantis and Endeavor

Launch Chandra

As the human spaceflight plans at NASA transition away from the Shuttle program, there have been lots of goodbyes. And hellos. Recently, both the Space Shuttles Atlantis and Endeavor found new permanent homes in their post-flight lives. Atlantis is now at the Kennedy Space Center Visitor Center in Florida, and Endeavor will be found from now on at the California Science Center in Los Angeles.

At each location, NASA held a welcome home/retirement party for the Shuttles. As we've talked about before , the Shuttle program did so much more than just take people into space (which, of course, is a very important job). It also delivered many unique and important telescopes and instruments into orbit – including the Chandra X-ray Observatory.

Look Back Time -- Remembering Franco

Chandra Deep Field South

The finite speed of light means that we must always be out of date, no matter how hard we strive to keep up with the times. The term look-back time refers to the time in the past when the light we now observe from a distant object was emitted. For example, deep Chandra observations have detected X-rays that have been travelling through intergalactic space for billions of years since they were emitted by jets of gas that were likely produced by rotating supermassive black holes. With these data, astronomers use Chandra and other telescopes as one-way time machines that enable them to see objects as they were in the past.

Revealing a Mini-Supermassive Black Hole

NGC 4178

One of the lowest mass supermassive black holes ever observed in the middle of a galaxy has been identified, thanks to NASA's Chandra X-ray Observatory and several other observatories. The host galaxy is of a type not expected to harbor supermassive black holes, suggesting that this black hole, while related to its supermassive cousins, may have a different origin.

Mission to the Universe: Stars and Stripes Family Fest

Mission to the Universe

The NH National Guard Child and Youth Program and NHNG Military Education Outreach Committee were proud to present a pilot science event with the Chandra Education & Outreach Group on October 14, 2012 in Concord, New Hampshire. The Mission to the Universe – Stars and Stripes Family Fest provided family friendly science activities from Chandra such as the "Here, There, and Everywhere" project, "STOP for Science" and the "Universe in a Jelly Bean Jar". Chandra science imager Joe DePasquale was on hand to demonstrate the concept of lensing to visitors and talk about how Chandra images are made. Chandra educator Donna Young discussed the life and death of stars.

A Planetary Nebula Gallery

Planetary Nebula Gallery

This gallery shows four planetary nebulas from the first systematic survey of such objects in the solar neighborhood made with NASA's Chandra X-ray Observatory. The planetary nebulas shown here are NGC 6543, also known as the Cat's Eye, NGC 7662, NGC 7009 and NGC 6826. In each case, X-ray emission from Chandra is colored purple and optical emission from the Hubble Space Telescope is colored red, green and blue.


Disclaimer: This service is provided as a free forum for registered users. Users' comments do not reflect the views of the Chandra X-ray Center and the Harvard-Smithsonian Center for Astrophysics.
Please note this is a moderated blog. No pornography, spam, profanity or discriminatory remarks are allowed. No personal attacks are allowed. Users should stay on topic to keep it relevant for the readers.
Read the privacy statement