Welcome back to Messier Monday! Today, we continue in our tribute to our dear friend, Tammy Plotner, by looking at the Cigar Galaxy – also known as Messier 82!
During the 18th century, famed French astronomer Charles Messier noticed the presence of several “nebulous objects” while surveying the night sky. Originally mistaking these objects for comets, he began to catalog them so that others would not make the same mistake. Today, the resulting list (known as the Messier Catalog) includes over 100 objects and is one of the most influential catalogs of Deep Space Objects.
One of these objects is the starbust galaxy known as Messier 82, which is also called the “Cigar Galaxy” because of its distinctive shape. Located about 12 million light-years away in the constellation Ursa Major, this galaxy’s starburst action is thought to have been triggered by interactions with the neighboring galaxy M81 (aka. Bode’s Galaxy).
There’s a bit of a mystery buried in the heart of the Cigar Galaxy, known more formally as M82 or Messier 82. Shining brightly in X-rays is a black hole (called M82 X-1) that straddles an unusual line between small and huge black holes, new research has revealed.
The new study reveals for the first time just how big this black hole is — about 400 times the mass of the sun — after about a decade of struggling to figure this out.
“Between the two extremes of stellar and supermassive black holes, it’s a real desert, with only about half a dozen objects whose inferred masses place them in the middle ground,” stated Tod Strohmayer, an astrophysicist at NASA’s Goddard Space Flight Center in Maryland.
Scientists figured this out by looking at changes in brightness in X-rays, which fluctuate according to how gas behaves as it falls towards a black hole. At the event horizon — that spot where you’re doomed, even if you’re light — is where the fluctuation happen most frequently. In general, larger black holes have these fluctuations less frequently, but they weren’t sure if this would apply to something that is of M82 X-1’s size.
But by going through old data from NASA’s Rossi X-ray Timing Explorer (RXTE) satellite — which ceased operations in 2012 — the scientists uncovered a similar pulsing relationship to what you see in larger black holes.
Specifically, they saw X-ray variations repeating 5.1 and 3.3 times a second, which is a similar 3:2 ratio to other black holes studied. This allows them to extend the measurement scale to this black hole, NASA stated.
Results of the study were published this week in Nature. The research was led by Dheeraj Pasham, a graduate student at the University of Maryland, College Park.
In a rare example of cloudy weather helping astronomy rather than hurting it, the team that found M82’s new supernova swung a telescope in that direction only because their planned targets for the night were obscured, a release stated.
The exploding star in the “Cigar Galaxy” was found at 7:20 p.m. UTC (2:20 p.m. EST) during a class taught by Steve Fossey at the University of London Observatory. Students Ben Cooke, Tom Wright, Matthew Wilde and Guy Pollack all participated in the discovery.
“The weather was closing in, with increasing cloud,” recalled Fossey in a press release, “so instead of the planned practical astronomy class, I gave the students an introductory demonstration of how to use the CCD camera on one of the observatory’s automated 0.35–metre [1.14-foot] telescopes.”
The students asked for M82, at which point Fossey saw a star that he couldn’t recall from examining the galaxy previously. A search of other images online revealed that something strange was happening, but clouds were obscuring everything quickly. The team focused on taking one- and two-minute exposures with different filters, and also using a second telescope to make sure there wasn’t something wrong with the first.
The team checked for any reports of a supernova, and finding none, Fossey sent a message to the International Astronomical Union’s Central Bureau for Astronomical Telegrams (which catalogs supernovae) and a United States team that does regular searches for exploding stars. Among his concerns was that it could be an asteroid lying in the way of the galaxy, but further spectroscopic measurements confirmed the “fluke” find, the release added.
The great thing about SN 2014J is it’s visible even in small telescopes. It’s also fairly close, by astronomical standards, at about 12 million light-years away. (The closest found since the invention of the telescope was Supernova 1987A, which exploded in February 1987 and was 168,000 light-years away.) Astrophotographers have already snapped many images of the exploding star.
“One minute we’re eating pizza, then five minutes later we’ve helped to discover a supernova,” stated Wright. “I couldn’t believe it. It reminds me why I got interested in astronomy in the first place.”
Wow! Now here’s a supernova bright enough for even small telescope observers to see. And it’s in a bright galaxy in Ursa Major well placed for viewing during evening hours in the northern hemisphere. Doesn’t get much better than that! The new object was discovered last night by S.J. Fossey; news of the outburst first appeared on the Central Bureau for Astronomical Telegrams “Transient Objects Confirmation Page”
Astronomers are saying this new supernova is currently at magnitude +11 to +12, so its definitely not visible with the naked eye. You’ll need a 4 inch telescope at least to be able to see it. That said, at 12 million light years away, this is (at the moment) the brightest, closest supernova since SN 1993 J kaboomed in neighboring galaxy M81 21 years ago in 1993. M81 and M82, along with NGC 3077, form a close-knit interacting group.
It’s amazing it wasn’t found and reported sooner (update — see below, as perhaps it was!). M82 is a popular target for beginning and amateur astronomers; pre-discovery observations show it had already brightened to magnitude 13.9 on the 16th, 13.3 on the 17th and 12.2 on the 19th. Cold winter weather and clouds to blame?
M82 is a bright, striking edge-on spiral galaxy bright enough to see in binoculars. Known as the Cigar or Starburst Galaxy because of its shape and a large, active starburst region in its core, it’s only 12 million light years from Earth and home to two previous supernovae in 2004 and 2008. Neither of those came anywhere close to the being as bright as the discovery, and it’s very possible the new object will become brighter yet.
PSN J09554214+6940260 is a Type Ia supernova. Type Ia (one-a), a dry term describing one of the most catastrophic events in the universe. Here a superdense white dwarf, a star only about the size of Earth but with the gravitational power of a sun-size star, pulls hydrogen gas from a nearby companion down to its surface where it adds to the star’s weight.
When the dwarf packs enough pounds to reach a mass 1.4 times that of the sun, it can no longer support itself. The star suddenly collapses, heats to incredible temperatures and burns up explosively in a runaway fusion reaction. What we see here on Earth is the sudden appearance of a brand new star within the galaxy’s disk. Of course, it’s not really a new star, but rather the end of an aged one.
I know you’re as excited as I am to get a look at this spectacular new star the next clear night, so I’ve prepared a couple maps to help you find the galaxy. The best time to see the supernova is as soon as the sky gets dark when it’s already up in the northeastern sky above the Dipper Bowl, but since it’s circumpolar for mid-latitude observers, you can check it out any time of night.
My maps show its position for around 8 o’clock. When you dial in the galaxy in your telescope, look for a starry point along its long axis west and south of the nucleus. All the fury of this fantastic blast is concentrated in that meek spark of light glimmering in the galactic haze.
UPDATE: Fraser and team from the Virtual Star Party actually imaged M82 on Sunday evening, and you can see it in the video below at the 22 minute mark. It really looks like a bright spot is showing up — and that’s about a day before it was announced. Did they catch it? In the video the galaxy appears upside down as compared to the images here: