Friday, September 28, 2012

A Busy Week in Astronomy

SN 2009ip Finally Becomes a Supernova

This week was full of interesting astronomy stories that received a lot of press coverage. I'll give a run-down of them in a moment, but I'll begin with a story that received little fanfare because it has moved too quickly for publicity. Last night a very interesting paper appeared on the arXiv: "The Unprecedented Third Outburst of SN 2009ip: A Luminous Blue Variable Becomes a Supernova" by Jon Mauerhan et al. This is about an object that was classified as a supernova back in 2009 but turned out not to be a supernova, after further study. The rapid brightening seen in 2009 was actually a violent outburst and a similar event was seen in 2010. A third outburst has now been observed, and this time a true core-collapse supernova appears to have occurred, as reported in the new paper. The progenitor star was a "luminous blue variable" (LBV), a massive star that is extremely bright, hot and erratic. Now, it appears to be gone. This is an exciting result, since it would be the first time that a massive, blue star, with well-observed LBV outbursts, has been caught turning into a core-collapse supernova.

The science is fascinating, but there's a remarkable aspect to how this work was done. The new spectra were obtained on September 16, 17, and 27 at Kitt Peak and on September 23 at Keck, and the new photometry was obtained on dates ranging from August 28 to September 26 at Lick, and on September 24 at Mt. Bigelow. All of those dates are for 2012. The paper was submitted on 2012 September 27. So, the paper was submitted on the same day as some of the data was obtained.  That is some super-fast data reduction, figure preparation and paper writing. I have no idea how you do that, and I don't care how much team work is involved and how little sleep you can tolerate. Also, before you question the caliber of the authors, it's not like these are charlatans mocking the ability to freely post to the arXiv. Having done some publicity work with the 2nd and 3rd authors, Nathan Smith and Alex Filippenko, I know about their high standards.

The case for it being a supernova wasn't always clear during the week. I followed the results as they came in thanks to Astronomer's Telegrams tweeted by Bob Rutledge, from McGill University. Bob is also the Editor-in-Chief of The Astronomer's Telegram. The first ATel I saw was "SN 2009ip: an LBV becomes a real supernova" but then follow-up observations by Swift and ground-based observatories suggested that a true supernova hadn't occurred because it didn't get brighter. Could astronomer's have been wrong again about SN 2009ip? I tweeted that rumors of the star's demise had been exaggerated. But then further, substantial brightening was noted by an observer from Coral Towers Observatory and a team from Harvard, strengthening the case for a supernova. At that stage Bob Rutledge told me he thought it was either a supernova or a "never-before-seen headfake by an LBV." New spectra from Nathan Smith and Jon Mauerhan and a team from UCSD then confirmed it as provided extra evidence it was a supernova.

Mauerhan et al. presumably submitted their paper very quickly so they would beat all of the different teams working on this object. Work on transient phenomena, like supernovas and gamma-ray bursts, tends to be a very competitive area. It wouldn't be surprising if several other papers appear in the next few weeks.

Returning to the science: the star that appears to have exploded was estimated to have had a mass between 50 and 80 times that of the sun, which is a whole lot of star. As Mauerhan et al point out, some models predict that very massive stars will end their lives as "failed" supernovas, where the star collapses to form a black hole without producing a spectacular light show. Based on the brightness of this event this wasn't a failed supernova, but this doesn't mean a black hole did not form. Many questions remain about the details of the explosion and the outbursts seen in 2009 and 2010.

A Cosmic Week

The week started with a Chandra X-ray observatory press release issued by us at the Chandra X-ray Center, on the detection of an enormous halo of gas around the Milky Way. A number of articles were written about the result including these by Jason Major, Matthew Francis, and Alex Knapp.

An artist's impression of the halo of gas around the Milky Way. Credit: NASA/CXC/M.Weiss; NASA/CXC/Ohio State/A Gupta et al
On Tuesday, the deepest image ever obtained was released. Articles on the eXtreme Deep Field, taken by the Hubble Space Telescope, include these by Nancy Atkinson and Clara Moskowitz.

The Hubble eXtreme Deep Field. Credit: NASAESA, G. Illingworth, D. Magee, and P. Oesch (University of California, Santa Cruz), R. Bouwens (Leiden University), and the HUDF09 Team
A day later, a new result came out in Nature about the origin of a bright supernova, SN 1006, in our galaxy. For more details, please see these articles by Kelly Oakes and Charles Choi. A beautiful composite image of the remains of this supernova appeared on the cover of Nature and was produced by us here at the Chandra X-ray Center. It includes Chandra, VLA and Hubble data.

SN 1006. Credit: X-ray: NASA/CXC/Rutgers/G.Cassam-Chenaï, J.Hughes et al.; Radio: NRAO/AUI/NSF/GBT/VLA/Dyer, Maddalena & Cornwell; Optical: Middlebury College/F.Winkler, NOAO/AURA/NSF/CTIO Schmidt & DSS
Yesterday there were two big astronomy stories. First, astronomers were able to study material very close to the event horizon of the supermassive black hole in M87. For details about the result and its implications, see these articles by Matthew FrancisJohn Matson, John Timmer, Charles Choi, and Clara Moskowitz.

Finally, the Mars Curiosity Rover has found evidence that a stream once ran across the area where it is  driving. Alicia Chang's article has appeared in many places, including the Huffington Post and numerous other articles have appeared, including these by Elizabeth Landau, Lisa GrossmanMarc Kaufman, and Amina Khan. It's clear that the Curiosity Rover has been an outstanding success and I look forward to more discoveries.

Saturday, September 15, 2012

Casting Call for Astronomy and UFO Enthusiasts

Most of the people I follow on twitter are involved in science, and I don't follow any celebrities, with the exception of Neil deGrasse Tyson, who probably qualifies as both. This means I don't hear a lot of news about entertainment and reality TV via twitter. However, this tweet by Kate Becker went against this trend:

Kate Becker @kmbecker
A disturbing definition of what it means to be an "astronomy enthusiast" - 

How could I resist looking at that URL? I expected to read about someone making fun of astronomers for being nerds or lacking fashion sense, but I found something quite different. The link is to a casting call web-site for reality TV shows, and the article's title is "MAJOR REALITY CABLE NETWORK SHOW SEEKS ASTRONOMY ENTHUSIASTS FOR RACHEL, NV FILMING". You can read the article yourself, but here's how it starts:

"Do you love watching the stars? Have you been down the Extraterrestrial Highway? Are you passionate about UFO watching? Have you ever wondered what goes on at the infamous AREA 51?"

It then goes on to mention two more times that they're seeking "ASTRONOMY ENTHUSIASTS" (their capitalization).

Who wrote this crap? I tweeted a complaint about the article and only a few minutes later *actual* astronomy enthusiasts started expressing their astonishment, even though it was late on a Friday afternoon.  The irony of course is that this is supposed to be about "reality" TV, not fictional TV.  They also didn't name the show - apparently in its 3rd season - which makes me wonder what's too embarrassing or off-putting about the show to mention, when their standards are low enough to link astronomy to UFOs.

A quick message to the show's producers: the "X-Files" was not a documentary. The movie "Armageddon" was science fiction, of the bad variety. "Contact" was a much better science fiction movie, and although it involved alien intelligence, no actual UFOs came to visit the Earth.

Here are some UFOs that real astronomers are interested in: "Ultra Fast Outflows" from rapidly growing black holes. How's that for a cheeky abbreviation?

What about a galaxy that looks like a UFO? It's clear that astronomers have a sense of humor.

Forget about Area 51. When I think of the number 51 in astronomy I think of M51, otherwise known as the Whirlpool Galaxy, a beautiful spiral:

M51: Credit: NASAESA, S. Beckwith (STScI), and The Hubble Heritage Team (STScI/AURA)
I also think of 51 Peg, the first star like the Sun that was discovered to have a planet orbiting it. Hundreds of exoplanets have now been found, showing that planets are common and increasing the chances that conditions suitable for life as we know it are common. But, that's very different from aliens conquering the vast challenges of interstellar travel and visiting us, resulting in orifice probing and government conspiracies across the world.

Astronomers have a diverse set of interests and beliefs, and sometimes they   can be eccentric, but one thing they don't support is fantasy and pseudoscience. I think the same applies to the vast majority of real astronomy enthusiasts, whether they are professional, amateurs or fans.

I leave you with a real flying saucer visiting another planet:

Mars Heat Shield in Detail. Credit: NASA/JPL-Caltech/MSSS

Tuesday, September 4, 2012


For this blog post I have a few short comments:

My first blog post, about challenges in studying dark energy, was part of a blog carnival about cosmology organized by the talented writer and physicist Matthew Francis. Here is Matthew's cosmology carnival post with links to the other blog posts, written by Katie Mack, Ethan Siegel, Matthew and me, with an excellent bonus post by Desiree Abbott about a different topic. Also, I encourage you to check out the first cosmology carnival post, containing some great material.

In "it's a small world" news, I understand that Katie Mack will soon be moving from Cambridge, UK to Melbourne in Australia, only a few hours drive from Albury, where I grew up.

I will continue the cosmology discussion in a future blog post, where I'll talk about the big challenges astronomers face in trying to make real progress in understanding dark energy.

Finally, what will this blog be about? It's too early to tell for sure, since I've never had a personal blog before, but most of it will be about science and science communication, as the sub-heading suggests, with a strong emphasis on astronomy and astrophysics. I work in publicity for a NASA space telescope named the Chandra X-ray Observatory, producing press releases and press conferences. I also did full-time research in astrophysics for a number of years. So, I'm particularly interested in new astrophysics results, and how these results are communicated. At some stage I may also come up with a real title for my blog.