May 25, 2017

16.02.11: The Tyche Files.

The realm of the outer solar system; here be hypothetical worlds? (Credit: NASA).

Something kept floating around our astro-radar yesterday as we busily wrote about comet flybys, launches, and wacky space weather. Titles like “New Solar System Planet!” and “Solar Companion Found!” kept making a spurious appearance from unverified sources. [Read more...]

December 2010: Life in the Astroblogosphere.

  

Last month’s “old school” Blue Moon…(Photo by Author).

    We’re back… December 2010 sees us here at Astroguyz wrapping up our 3-year plus quest for an online science teaching degree and a return to full-bore content creation.  And none too soon, as December is generally our busiest (and most intriguing!) month of the year… [Read more...]

Astro-Challenge: Spy a Microquasar.

Artists' Conception of SS 433. (NASA/CXC/M. Weiss).

Artists' Conception of SS 433. (NASA/CXC/M. Weiss).

 

   So, you’ve seen everything the night sky has to offer? You say you’ve seen all breeds of eclipses and deep sky objects, and have grown tired of showing the neighbors Saturn and the Ring Nebula? Well, we’ve got a challenge for you. This week’s object will require dark skies, a good finder chart, and a generous aperture telescope.  About 4 degrees northwest of the 3rd magnitude star Delta Aquilae lies +14.1 magnitude SS 433. [Read more...]

23.06.10- Swift Spies Black Holes Feeding on Galaxy Mergers.

Anatomy of an AGN. (Credit: NASA/Swift/EPO/Sonoma State/Aurore Simonnet).

Anatomy of an AGN. (Credit: NASA/Swift/EPO/Sonoma State/Aurore Simonnet).

 

   NASA’s orbiting Swift telescope is in the news again, this time providing a key link between energetic nuclei and active galaxy mergers. The findings come after a survey conducted since 2004 by Swifts’ Burst Alert Telescope (BAT) of active galactic nuclei. A small percentage of these (less than 1 %) are extremely active, emitting 10 billion times the equivalent solar output. While theories have long posited that galaxy mergers feed and create galactic mass black holes, the observations carried out by Swift catch these monsters switching on in their energetic youth, and thus provide insight into their evolution. Only instruments such as BAT can penetrate the thick layers of gas and dust masking these massive black holes, which emit copious amounts of radiation in the hard x-ray spectrum. In fact, Swift has built the first ever comprehensive all sky survey in hard x-rays, with sensitivity to active galactic nuclei (AGN) 650 million light years distant. In the process, Swift has also uncovered numerous unknown AGN. The picture emerging will no doubt force scientists to rethink galaxy evolution; about 25% of the galaxies that BAT sees are potential close mergers, and 60% of those are destined to merge in the next 1 billion years or so. As we fill in the galaxy “family scrapbook,” key information will be deduced about how common (or rare) our own Milky Way galaxy is. And yes, our galaxy does harbor a galactic mass black hole of its own! And we’re also due for a collision of our own with the Andromeda galaxy in about 3 billion years, with the resulting merger tentatively dubbed Milkomeda… will whatever we evolve into, (or get replaced by) be blogging then? Imagine the views as the Andromeda closes in!

23.05.10-Are Black Holes the Key to Dark Matter?

Artist's impression of a torus surrounding a massive black hole. (Credit V. Beckmann.NASA).

An artist’s conception of a gas torus surrounding a super-massive black hole. (Credit: V.Beckmann/NASA).

   For the past few decades, astronomers have been hot on the trail of the “missing” part of our universe. About 23 percent of our universe appears to be comprised of dark matter, non-luminous material that gives itself away only via gravitational interaction. Pinning down dark matter has been the name of the cosmological game, and researchers have looked at everything from MACHOs (Massive Compact Halo Objects) to WIMPs (Weakly Interacting Massive Particles) to everything conceivable, however bizarre or mundane, in between. Now, researchers at the National Autonomous University of Mexico may have gained a key insight into the nature of dark matter, as well as the evolution of galaxies and how the super-massive black holes at their heart are formed. Researchers William Lee and Xavier Hernandez studied the absorption rates of these massive beasts, noting how simulations stacked up with what we observe in the universe we see today. Their findings suggest that dark matter at the cores of galaxies should be fairly homogonous; at a critical mass larger than seven solar masses per cubic light year, a runaway effect occurs, twisting and altering galaxies from the stately whirlpool we see today. Of course, with this mass limit constraint, one could easily ask the question; how did these black holes reach multi-million solar mass status in the first place?  Further studies and data gathered by platforms such as the James Webb Space Telescope will no doubt shed “new light” (bad pun intended) on dark matter as well as tweak standard models and refine the nature of its role in the evolution of the cosmos.

27.03.10- Modeling Black Holes.

Simulation of the environs of a black hole. (Credit: NASA).

Simulation of the environs of a black hole. (Credit: NASA).

 

   Researchers are calling in the big guns in the quest to understanding black holes. Specifically, scientists at the Rochester Institute of Technology are using time on some of the fastest and most powerful computers in use to model and predict the activity of super massive black holes. But these aren’t your ordinary off the shelf PCs; their laboratory New Horizons machine is a computer cluster of 85 nodes with 4 processors that is capable of passing data at a rate of 10 gigabytes per second. Try that on your family Mac book! Further grants totaling $2.9 million will enable the team to hone their theoretical models over the next 3 years on ever faster machines. “It’s a thrilling time to study black holes, ” states center director Manuela Campanelli. If predictions match observations, these models may also serve as the best proof yet of Einstein’s General Theory of Relativity…more to come!

20.03.10: Spying a Black Hole Welterweight.

An Artist's conception of NGC 5408 X-1. (Credit: NASA).

An Artist's conception of NGC 5408 X-1. (Credit: NASA).

  

   Astronomers now have observational evidence for a missing class of black hole. Stellar mass black holes, those up to about 10 solar masses, are well known as the remnants of supernovae. Likewise for supermassive black holes of 10,000 solar masses or greater known to reside in the hearts of galaxies like our own. The “missing link” in astrophysics has been intermediate mass black holes, or those between 100 and 10,000 solar masses. Now, scientists at the Goddard Space Flight Center in Greenbelt Maryland have used the XMM-Newton and Swift X-ray satellites to pinpoint a likely candidate; NGC 5408 X-1, a black hole with about 1,000 to 9,000 solar masses in a galaxy about 15.8 million light years away in the constellation Centaurus. This would include an event horizon about 3,800 to 34,000 miles across. An X-ray flux occurs once every 115.5 days, strongly suggesting that NGC 5408 X-1 has a stellar companion accreting donor material. This star would be 3-5 times the Sun’s mass.   “Astronomers have been studying NGC 5408 X-1… because it’s one of the best candidates for an intermediate mass black hole.” States Philip Kaaret of the University of Iowa. The contributing companion also gives astronomers the unique opportunity to probe the near-space environment as well as study this intermediate class of enigmatic objects.

02.11.09:The Low-Down on LOFAR.

The LOFAR station at Effelsberg, with the low-band masts in the foreground and the high band antenna in the background. (Credit: The Netherlands Institute for Radio Astronomy).

The LOFAR station at Effelsberg, with the low-band masts in the foreground and the high band antenna in the background. (Credit: The Netherlands Institute for Radio Astronomy).

European radio astronomers at the Netherlands Institute for Radio Astronomy (ASTRON) have recently opened a potentially new window on the universe with an exotic new instrument. Dubbed LOFAR, or the Low Frequency Array, this unique instrument will examine the sky at extremely low radio frequencies, with a low band of 30 to 78 MHz and a complimenting high band of 120 to 168 MHz. In contrast, the radio dish at the Arecibo Observatory in Puerto Rico operates in a range of 400-5000 MHz. We’re talking very low frequencies, in a range not well understood. Three arrays currently centered on Exloo in the Netherlands saw first “radio light” earlier this year, examining the powerful radio source Cygnus A, a suspected black hole candidate. As computer power increases, scientists hope to add arrays across Europe from Britain to the Ukraine to increase the resolution of the array. The low gain antenna masts are simple and cheap to construct, and are basic omni-directional dipole antennas utilizing a synthetic aperture. LOFAR will map events at low radio frequencies, from ionization in the Earth’s atmosphere caused by gamma-ray bursts to corneal mass ejections on the Sun to re-ionization of neutral hydrogen in the primordial universe. And that’s not to mention any surreptitious discoveries that always seem to crop up when a new portion of the electromagnetic spectrum gets analyzed… perhaps some ultra-advanced race communicates via low frequency black hole resonances? I seem to remember a plot in Arthur C. Clarke’s Imperial Earth that involved intelligent aliens and low frequency waves… watch for LOFAR “antenna farms” cropping up along the European country-side soon!

June 2009 News & Notes.

Blast!

Blast! (Credit: Marc Halpern/the Blast Collaboration).

BLAST takes off! Recently, scientists got a look into some of the earliest moments of the universe. BLAST, the Balloon borne Large Aperture, Sub-millimeter Telescope, is an unlikely looking instrument in an unlikely place. Carried on a long tether and based in the Antarctic, BLAST can stay aloft for weeks at a time, observing the sky at very far infra-red frequencies. [Read more...]

Review: Death from the Skies! by Philip Plait.

Death from the Skies.

Get it now, before the Apocalypse…

Author and astronomer Phil Plait has a secret to share; the universe is out to kill you. It turns out that general feeling of paranoia we all feel at one time or another is indeed warranted; from meteors to black holes to alien invasions, the cosmos will eventually “get” us. In his latest book, Death from the Skies out recently from Penguin Books  Professor Plait (of Bad Astronomy fame) engagingly takes us through the realm of cosmic catastrophe, whacking humanity again and again with his “what if?” dramatic intros. [Read more...]