Astronomy Picture of the Day: 01/11/14 - NGC 1316

When two galaxies collide, the aftereffects are typically noticeable to any outside onlookers (the tad pole galaxies and the Mice galaxies are two notable examples). However, the aftereffects are generally not nearly as peculiar as what we see here, with this unusual galaxy. NGC 1316 (its formal designation) is located about 75 million light-years from Earth in the constellation of Fornax. This jumbled mess of a galaxy spans about 60,000 light-years across - making it much smaller than our home galaxy of the Milky Way - yet it contains exponentially more gas and dust, which give life to new stars.

Astronomers have deduced that this unique looking galaxy is actually an elliptical galaxy of epic proportions, but by a strange twist of fate, it just so happens to have the dark dust (or knot) lanes typically attributed to spiral galaxies -- suggesting that one or more of the galaxies absorbed by NGC 1316 were spiral in nature. Similarly, more evidence was uncovered to suggest that NGC 1316 is the result of several celestial collisions. This evidence comes in the form of several low-mass globular clusters found lurking within the vicinity of NGC 1316"s central region (yes, it has one). Many of the stars that inhabit the cluster still bear the scars of the long-ended mergers, especially as far as distribution is concerned.

Sources & Further Reading: http://www.fromquarkstoquasars.com/apod-ngc-1316/

Image Credit: P. Goudfrooij (STScI), Hubble Heritage Team, (STScI/AURA), ESA, NASA

Astronomy Picture of the Day: 01/04/14 - The Fireworks Galaxy

To start off 2014 right, this is the Fireworks Galaxy, aptly named given its brilliance. NGC 6946, as it is formally known as, lies about 10 million light-years from Earth in the constellation of Cepheus. When it was originally discovered by Sir William Herschel, the galaxy was widely believed to be a member of our local group, which is made up of over 50 galaxies, including several other dwarf-galaxies. It wasn"t until years later that astronomers discovered that the reddening seen enveloping the galaxy was from interstellar dust grains, obscuring our view (instead of red-shift).

Speaking of red, the applicable areas are star forming regions, teeming with new-life -- while the blue bits are actually celestial members of our own galaxy, which are obstructing our view of NGC 6946. Interestingly, several new supernova remnants have been discovered each year for the last 60 lurking within NGC 6946"s spiral arms. This is very unusual, as it is normal to only witness one supernova blast every 30 years in galaxies similar to our own.

References & Further Reading: http://www.fromquarkstoquasars.com/apod-fireworks-galaxy/

Image Credit: NASA/JPL-Caltech/R. Kennicutt (U. of Ariz./Inst. of Astr., U. of Cambridge) and the SINGS Team

Astronomy Picture of the Day: 12/29/13 - PKS 0745-19

Located in a galaxy far, far away in the constellation known as Puppis, lies some of the most massive black holes discovered to date. Some of which, weigh any where from ten to four billion solar masses, effectively reaffirming the long held notion that black holes are strange objects indeed, and there is still much that we don"t understand about them.

PKS 0745 is an elliptical galaxy located approximately 1.3 BILLION light-years from Earth, and it is the central galaxy from a cluster of galaxies known as PKS 0745-19. A survey was conducted with eighteen of the supermassive black holes from PKS 0745, including the black hole at PKS 0745"s galactic center. What they found, is that some of these "ultramassive" black holes are over ten times more massive than previously thought. Interestingly, each "ultramassive" black hole currently discovered lurking at the heart of a galaxy contains an abnormally large quantity of hot gas, which produces diffuse x-ray emissions (pictured here in purple). When these black holes munch on stellar material, cavities are created within the surrounding gas, prohibiting the gas from cooling and collapsing to form new stars.

Optical data (yellow) was provided by the Hubble Space Telescope, with x-rays (purple) coming from the Chandra x-ray observatory. Also used in this composite is radio data from the NSF"s "Very Large Array "(JVLA) and the Australia Telescope Compact Array (ATCA). Infrared data came from the 2 Micron All-Sky Survey (2MASS).

References & Further Reading: http://www.fromquarkstoquasars.com/apod-pks-0745/

Image Credit: X-ray: NASA/CXC/Stanford/Hlavacek-Larrondo, J. et al; Optical: NASA/STScI; Radio: NSF/NRAO/VLA

Astronomy Photo of the Day: 12/18/13 - The Circinus Galaxy

Chandra - along with ESO"s Very Large Telescope Array - spied a bright, variable supernova blast located in a galaxy 12 million light-years away. This image is a composite showing the central region of the galaxy in question, which is typically referred to as the Circinus galaxy.

In the lower right hand corner of the image, the blue source of light is the supernova blast itself (designated "SN 1996cr"). It was originally discovered back in 2001 (though the light from the actual explosion arrived more than a decade before it was even discovered). Despite there being so many stars in the night sky, it"s pretty infrequent that we observe these celestial events in independent galaxies. By some estimations, one should expect to see one supernova explosion once every 50 years per galaxy! The last verified explosion in the Milky Way was observed back in 1604 by the famed astronomer, Johannes Kepler (many other contenders have been noted in recent years though).

Furthermore, some of you may recall the famous supernova SN 1987A, which occurred in a galaxy approximately 160,000 light-years away -- It"s quite similar to supernova SN 1996cr in many ways, but SN 1996cr spits out almost 1000 times more radio and x-ray emissions.

References & Additional Reading: http://www.fromquarkstoquasars.com/astronomy-photo-of-the-day-121813-the-circinus-galaxy/

Image Credit: X-ray (NASA/CXC/Columbia/F.Bauer et al); Optical (NASA/STScI/ UMD/A.Wilson et al.)

Astronomy Picture of the Day: 12/16/13 - The Pinwheel Galaxy

The Pinwheel Galaxy, which can be found more than 21 million light-years from Earth in the constellation of Ursa Major, is one of the most majestic galaxies in the observable universe. The only thing more impressive than the galaxy"s beauty is its size. It comes in with a staggering diameter of 170,000 light-years, making it about 70% larger than our home galaxy, the Milky Way (it, in contrast, is about 100,000 light-years across).

You may not know this, but capturing a detailed image of distant galaxies isn"t as easy as clicking a button on a camera. For instance, take the beautiful photograph of the Pinwheel Galaxy seen here. Instead of it being one shot, it"s actually a composite of four shots taken in infrared, visible light, ultraviolet and x-ray. Optical data was collected by the Hubble Space Telescope (in yellow). The Chandra X-ray Observatory captured the galaxy at x-ray wavelengths (seen in purple), while the Spitzer Space Telescope viewed it at infrared wavelengths (seen in red). Ultraviolet data was taken by GALEX - the Galaxy Evolution Explorer - in blue.

Sources & Further Reading: http://www.fromquarkstoquasars.com/astronomy-picture-of-the-day-121613-the-pinwheel-galaxy/

Image Credit: Chandra X-ray Observatory, Spitzer Satellite, Hubble Space Telescope, and GALEX Satellite

Astronomy Picture of the Day: 12/05/13 – E0102

In one of the most beautiful images ever taken of the Small Magellanic Cloud (SMC), Hubble reveals a greenish-blue shell of debris from a massive star that went supernova. The remnant, which is know as "E0102" for short (more formally known as 1E0102.2-7219) -- is located approximately 210,000 light-years away from Earth in the satellite galaxy of the Milky Way. (Locally, it"s about 50 light-years away from N 76, a star-forming region found in the outer trenches of the SMC).

The stark contrast in coloring in this composite image can be attributed to different elements located within the star forming region of the Small Magellanic Cloud. N 76 is primarily composed of glowing hydrogen emissions. Whereas, E0102 is an oxygen-rich environment that has a startling absence of hydrogen and helium (key components in star formation). It is believed that the abundance of oxygen in the surrounding environment can be attributed to a very large, old and unstable Wolf-Rayet star. Over the course of the last hundreds of thousands of years, the star lost most of its hydrogen envelope through stellar winds. Said material then carried off the outer-most shell of the star, leaving behind oxygen once the star exploded. Shortly after, the core contracted to become a neutron star.

As far as the age of the remnant is concerned, it is relatively young compared to many of its similar counterparts. The original supernova blast was estimated to have taken place about 2,000 years ago and is just now starting to expand into the interstellar medium. (This would essentially mean that the explosion occurred more than 230,000 years ago. It just took so long for the light from the event to arrive on Earth)

Sources & Further Reading: http://www.fromquarkstoquasars.com/astronomy-picture-of-the-day-120513-e0102/

Image Credit: NASA, ESA and the Hubble Heritage Team STScI/AURA

Astronomy Picture of the Day: 12/03/13 - M96

In this lovely image, captured by the Caelum Observatory, one can see the colorful portrait of a swirling spiral galaxy as it dances about the abyss of interstellar space.

Messier 96, as its called (also known as NGC 3368), is a primary member of the Leo I galaxy group, a collection of 8 to 24 galaxies (at least 3 of which are Messier objects) located more than 38 million light-years away (in the direction of the constellation of Leo).

The galaxy in question is quite large, spanning some 100,000 light-years across (making it equivalent in size to our own galaxy, the Milky Way). The spiral arms are particularly lovely; appearing dominant as they branch away from the central nucleus of Messier 96, before decreasing in brightness to a faint glow once reaching the outer cusp of the galaxy.

Sources & Further Reading: http://www.fromquarkstoquasars.com/astronomy-picture-of-the-day-120313-m96/

Image Credit: Adam Block (Caelum Observatory), Acknowledgement: R. Jay GaBany

Astronomy Picture of the day; 11/24/13 - NGC 7027

It"s absolutely fascinating to me that nebulae that form in the same fashion (also from the same general size and type of star) can create structures that look absolutely nothing alike. This is a great example of such, a planetary nebula, located approximately 3,000 light-years from Earth (in the Cygnus constellation). These nebulae form after sun-like stars exhaust their supply of hydrogen found in their core, causing the stars to balloon in size whilst the process of helium consumption begins. Throughout this process, the outer-layers of material peel off (similar to an onion), forming a planetary nebula (a fate our sun will experience eventually.).

Sources & Additional Reading: http://www.fromquarkstoquasars.com/astronomy-picture-of-the-day-112413-ngc-7027/

Image by Arnie Rosner (Additional Credit: W. B. Latter (SIRTF /Caltech) et al., NICMOS, HST, NASA)

Galaxy Classifications: From Dwarfs to Spirals and Beyond

Surprisingly, over the course of most of humanity"s existence, we had no idea that other galaxies even existed. All we could see was our own little corner of the universe. It wasn"t until the early 1900"s that the nature of the so-called "Andromeda nebula" was discerned. Edwin Hubble settled the galaxy vs. nebula debate in 1925, and it was finally revealed that this "nebula" was actually a galaxy containing some 400 billion stars and not simply an extension of our own galaxy. Almost 100 years later, our reality (and relative insignificance) is well known, as we are now aware of the fact that the universe contains several BILLION large galaxies, many of which are similar to our own (current estimates guess that there are 100 to 200 billion galaxies in the Universe). With that revelation, we"ve learned that galaxies come in all shapes and sizes too. "So what other kinds of galaxies are there," you might ask? Here are the main types:

To learn about all the galaxy types, see:
http://www.fromquarkstoquasars.com/galaxy-classifications-from-dwarfs-to-spirals-and-beyond/

Image source:
http://qproject.net/Universe/281236_534286593250951_619997205_n.jpg