February 19, 2019

22.01.11: A Quasar Campaign.

A call recently went out from the American Association of Variable Star Observers (AAVSO) that we thought was worth passing along. Specifically, Alert Notice 430 is calling for well-equipped and skilled observers to monitor to two exotic objects: Blazar-type quasars 3C 273 and 3C 279. If 3C 273 is sounding familiar, that’s because it was one of our astronomy challenges last year; at around magnitude +12.7, 3C 273 was the first quasar identified as such and is one of the brightest quasars in the sky.

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Astro-Challenge: Spy a Microquasar.

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.

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23.06.10- Swift Spies Black Holes Feeding on Galaxy Mergers.

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!

Astro-Challenge of the Week: Can you Spot the Brightest Quasar?

This week, we here at Astroguyz are going to show you how to go after that most elusive of beasts; a quasar. Even seasoned amateurs do not always realize that some of the brighter denizens of this elusive class of beasts are bag-able with a telescope of moderate-sized aperture. Of course, don’t expect to see much; part of the fun of this challenge is the fact you can see it at all, and the wonder of what the object actually is. Our visual prey is 3C 273 is the constellation Virgo. This object was the 273th listed in the 3rd Cambridge Catalog of radio sources, and at a 16% red-shift, stands at “only” about 2 billion light years distant! This also gives it an apparent recessional velocity of 30,000 miles per second. Visually, 3C 273 hovers at about magnitude +12.2, although it has been known to vary by about magnitude 0.5 in either direction. Its coordinates are;

Right Ascension: 12 Hours 29 minutes 6 seconds.

Declination: +02° 03’ 06” N

A good series of finder charts courtesy of the AAVSO may be had here; 3C 273 is about 4.7° NW of the star Gamma Virginis and very near the galaxy NGC 4536.

Now for the mind-blowing part; the absolute magnitude of 3C 273 is about -26; if this object was 10 parsecs distant, it would visually rival our own Sun! Its output also tops our own Milky Way galaxy by a factor of x100! As you can see, writing a post on the topic of quasars demands the extreme over-usage of exclamation points. 3C 273 is a worthy target for aperture 6” or greater, and stands as the farthest object you’ll probably ever lay eyes on. It also serves as a good reply to that common neophyte question heard at star parties; “So, how far can you see with that thing?” And just think, the light left 3C 273 when the Proterozoic era was the newest, greatest thing here on Earth… imaging may even help you grab this beast. Amateurs have even successfully recorded a spectrum of 3C 273 and measured its red-shift, a good reply next time someone asks you; “Yeah, but how do YOU know the universe is expanding?”  As the waning Moon slides out of the evening sky, I invite you add a quasar to your visual athlete-life list!

This week’s astro-word of the week is Quasar. Short for Quasi-Stellar object, this class of amazing objects was not even heard of until the early 1960s. Much controversy raged for decades as to exactly what astronomers were seeing; theories ranged from white holes to anti-matter fueled stars in the early universe. With the advent of accretion disc theory as a massive energy source outlined in the 1970’s a model of quasars slowly emerged; the consensus now is that we are seeing highly energetic galactic nuclei early in their youth. Perhaps the supermassive black hole at the core of our own Milky Way Galaxy was once a quasar itself, gobbling up interstellar matter and emitting massive amounts of x-rays and radio waves before settling down to the relatively placid state we see today. Other classes of objects such as blazars and radio galaxies have further filled in the classification gaps, and the massive amounts of energy we see in some quasars are thought to simply be the result of our viewing angle here on Earth. The brightest quasars devour perhaps 1000 solar masses of material a year, and the most distant recorded is CFHQS J2329-0301 discovered in 2007, with a red-shift of 6.43 and about 13 billion light years distant. This puts it in the realm of the very early universe, which is only 13.7 billion years old!

10.04.10- Radio Astronomers Refine Celestial Grid.

Getting a good fix on positions both on the Earth and in the sky is tougher than it may sound. Tectonic plates move. The Moon raises tides under our feet. The whole planet orbits our Sun, which is itself flying about the galaxy and getting jostled by other stars, as the galaxies themselves are flying apart. Last year, however, astronomers at the National Science Foundation’s Very Long Baseline Array of radio telescopes tackled the problem in a novel way. Using 35 radio telescopes worldwide, they monitored and measured the positions 243 quasars over a 24 hour period starting November 18th 2008. Quasars are ideal candidates for this kind of measurement because of their extreme distance. These high precession measurements break the old record for the most radio dishes employed, which stood at 23. The telescopes utilized a method known as Very Long Baseline Interferometry, which combines simultaneous signals collected over individually spaced telescopes to increase resolution power. Headquartered in Socorro, New Mexico, the VLA’s data will not only refine astronomical measurements, but increase the accuracy of geophysical science as well.

18.03.10: ALMA in Action.

A unique trio of antennae has been successfully installed in the high Chilean desert. ALMA, the Atacama Large Millimeter Array, is a series of 12-meter diameter antennae that will scan the sky between the infrared and radio wavelengths. This area of the spectrum is strongly absorbed by atmospheric water vapor, hence the high and dry locale of 9,500 on the Chanjnantor plateau. Recently, engineers linked the first of three antennae to observe an astronomical source; quasar 1924-292. The link up is crucial to ALMA’s use as an interferometer, and should start producing its first scientific results in 2011. Ultimately, ALMA will be a series of 66 dishes working in unison to probe the cosmos.

21.01.10-Joint U.S.-Mexico Telescope to Survey the Infrared Sky.

Construction has begun on a telescope that will scan a little understood part of the electromagnetic spectrum. Last summer, optical engineers at the University of Arizona in Tucson began the casting process for the 6.5 meter mirror that will ultimately be part of the San Pedro Martir Telescope in the Mexican observatory complex of the same name. Located in Baja, California, the site will offer pristine views of the northern and much of the southern skies.  The mirror is being figured for a very fast, f/1.4 focal ratio for a very special purpose; to complete the most comprehensive survey of the infrared sky. When completed in 2017, the San Pedro Martir Telescope will survey the infrared sky with unprecedented accuracy, going 100 to 500 times fainter than the Two Micron All Sky Survey (2MASS) completed in 2004. This is part of the Synoptic All-Sky Infrared Imaging Survey (SASIR) and will open up a new realm of infrared astronomy. Among the goodies expected to be uncovered are distant quasars, super massive black holes, and perhaps nearby faint red dwarf stars in our own solar neighborhood. For example, the jury is still out on whether or not our own Sun might have a faint, small companion on a long term orbit… now that discovery would be  would be some serious news!