galaxy formation and evolution

Although galaxy formation and evolution are still far from being fully understood, the conditions we see within certain galaxies – such as so-called starburst galaxies  – can tell us a lot about how they have evolved over time. Starburst galaxies contain a region (or many regions) where stars are forming at such a breakneck rate that the galaxy is eating up its gas supply faster than it can be replenished!

NGC 4536 is such a galaxy, captured here in beautiful detail by the Hubble?s Wide Field Camera 3 (WFC3). Located roughly 50 million light-years away in the constellation of Virgo (The Virgin), it is a hub of extreme star formation. There are several different factors that can lead to such an ideal environment in which stars can form at such a rapid rate. Crucially, there has to be a sufficiently massive supply of gas. This might be acquired in a number of ways – for example by passing very close to another galaxy, in a full-blown galactic collision, or as a result of some event that forces lots of gas into a relatively small space.

Star formation leaves a few tell-tale fingerprints, so astronomers can tell where stars have been born. We know that starburst regions are rich in gas. Young stars in these extreme environments often live fast and die young, burning extremely hot and exhausting their gas supplies fairly quickly. These stars also emit huge amounts of intense ultraviolet light, which blasts the electrons off any atoms of hydrogen lurking nearby (a process called ionization), leaving behind often colorful clouds of ionized hydrogen (known in astronomer-speak as HII regions).

Credit: ESA/Hubble & NASA
Text Credit: European Space Agency

Hubble Space Telescope

Time And Space


Stargate SG-1 meme: four quotes (4/4)

“The SGC may be the single most important human endeavor for the future of mankind.”  Jack O’Neill (quoting Daniel Jackson), Forever In a Day

Superluminous supernova marks the death of a star at cosmic high noon

The death of a massive star in a distant galaxy 10 billion years ago created a rare superluminous supernova that astronomers say is one of the most distant ever discovered. The brilliant explosion, more than three times as bright as the 100 billion stars of our Milky Way galaxy combined, occurred about 3.5 billion years after the big bang at a period known as “cosmic high noon,” when the rate of star formation in the universe reached its peak.

Superluminous supernovae are 10 to 100 times brighter than a typical supernova resulting from the collapse of a massive star. But astronomers still don’t know exactly what kinds of stars give rise to their extreme luminosity or what physical processes are involved.

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A ‘matryoshka’ in the interstellar medium

As if it were one of the known Russian dolls, a group of astronomers, led by researchers at the Instituto de Astrofísica de Canarias, (IAC) has found the first known case of three supernova remnants one inside the other. Using the programme BUBBLY, a method developed within the group for detecting huge expanding bubbles of gas in interstellar space, they were observing the galaxy M33 in our Local Group of galaxies and found example of a triple-bubble. The results, which were published yesterday in the journal Monthly Notices of the Royal Astronomical Society, help to understand the feedback phenomenon, a fundamental process of star formation and in the dissemination of metals produced in massive stars.

The group has been building up a data base of these superbubbles with observations of a number of galaxies and, using the very high resolution 2D spectrograph, GHaFaS (Galaxy Halpha Fabry-Perot System), on the 4.2 m William Herschel Telescope (WHT) of the Isaac Newton Group of Telescopes (Roque de los Muchachos Observatory, La Palma), has been able to detect and measure these superbubbles, which range in size from a few light years to as big as a thousand light years across.

Superbubbles around large young star clusters are known to have a complex structure due to the effects of powerful stellar winds and supernova explosions of individual stars, whose separate bubbles may end up merging into a superbubble, but this is the first time that they, or any other observers, have found three concentric expanding supernova shells.

“This phenomenon -says John Beckman, one of the co-authors on the paper- allows to explore the interstellar medium in a unique way, we can measure how much matter there is in a shell, approximately a couple of hundred times the mass of the sun in each of the shells”. However, if it is known that a supernova expels only around ten times the mass of the sun, where do the second and third shells get their gas from if the first supernova sweeps up all the gas?

The answer to that must come from the surrounding gas and in the inhomogeneous interstellar medium. “It must be -says Artemi Camps Fariña, who is first author on the paper-, that the interstellar medium is not at all uniform, there must be dense clumps of gas, surrounded by space with gas at a much lower density. A supernova does not just sweep up gas, it evaporates the outsides of the clumps, leaving some dense gas behind which can make the second and the third shells”.

“The presence of the bubbles -adds Artemi- explains why star formation has been much slower than simple models of galaxy evolution predicted. These bubbles are part of a widespread feedback process in galaxy disc and if it were not for feedback, spiral galaxies would have very short lives, and our own existence would be improbable”, concludes. The idea of an inhomogeneous interstellar medium is not new, but the triple bubble gives a much clearer and quantitative view of the structure and the feedback process. The results will help theorists working on feedback to a better understanding of how this process works in all galaxy discs.

A Journey of Eight Years

We’re taking time to highlight our progress and accomplishments over the past 8 years. Join our historical journey!

Obama Visit to NASA in 2010 

President Barack Obama visited our Kennedy Space Center in Florida to deliver remarks on the bold new course the administration is charting for America’s space program. During a speech at the center, President Obama said, “I believe we can send humans to orbit Mars and return them safely to Earth. And a landing on Mars will follow. And I expect to be around to see it.” R  

Commercial Crew

Our Commercial Crew and Cargo Program is investing financial and technical resources to stimulate efforts within the private sector to develop safe, reliable and cost-effective space transportation systems. This program has allowed us to continue to reach low-Earth orbit, even after the retirement of the Space Shuttle Program. In the coming years, we will once again launch U.S. astronauts from American soil to the International Space Station through this commercial partnership.  

Revamping KSC: Vehicle Assembly Building

Our Vehicle Assembly Building (VAB) at Kennedy Space Center served through the Apollo and Space Shuttle Programs, and is now undergoing renovations to accommodate future launch vehicles…like our Space Launch System (SLS) rocket that will carry astronauts to deep space destinations, like Mars. Already, shuttle-era work platforms have been removed from the VAB to make way for our advanced heavy-lift launch vehicle, SLS.  

Revamping KSC: Pad 39B

For the first time since our Apollo-era rockets and space shuttles lifted off on missions from Launch Complex 39 at our Kennedy Space Center in Florida, one of the launch pads is undergoing extensive upgrades to support our 21st century space launch complex. At launch pad B, workers are making upgrades to support our Space Launch System (SLS) rocket and a variety of other commercial launch vehicles. .

Commercial Resupply Program

Our commercial partnerships with companies like SpaceX and Orbital ATK are allowing us to find new ways to resupply the International Space Station. Orbital ATK’s Cygnus cargo spacecraft is shown being captured using the Station’s Canadarm2 robotic arm. Packed with more than 5,100 pounds of cargo and research equipment, the vehicle made Orbital ATK’s fifth commercial resupply flight to the station in October 2016.  

Pluto Flyby

After a seven-year journey, our New Horizons spacecraft arrived at dwarf planet Pluto. It captured this high-resolution enhanced color view of the planet on July 14, 2015. The image combines blue, red and infrared images taken by the craft’s imaging camera. Pluto’s surface sports a remarkable range of subtle colors, enhanced in this view to a rainbow of pale blues, yellows, oranges, and deep reds. Many land forms have their own distinct colors, which tell a complex geological and climatological story.   

Juno at Jupiter

Juno’s 2011 launch brought it into orbit around Jupiter. This composite image depicts Jupiter’s cloud formations as seen through the eyes of Juno’s Microwave Radiometer (MWR) instrument as compared to the top layer, a Cassini Imaging Science Subsystem image of the planet. The MWR can see several hundred miles (kilometers) into Jupiter’s atmosphere with its largest antenna. The belts and bands visible on the surface are also visible in modified form in each layer below.  

Orion EFT-1

As we strived to make deep-space missions a reality, on Dec. 5, 2014, a Delta IV Heavy rocket lifted off from Cape Canaveral carrying our Orion spacecraft on an unpiloted flight test to Earth orbit. During the two-orbit, four-and-a-half hour mission, engineers evaluated the systems critical to crew safety, the launch abort system, the heat shield and the parachute system.  

 Building of SLS

Meet the Space Launch System, our latest rocket system and see how it stacks up (no pun intended) to earlier generations of launch vehicles. While we engaged commercial partners to help us reach low-Earth orbit, we also were able to focus on deep-space exploration. This resulted in the creation of SLS, the world’s most powerful rocket and the one that will carry humans to deep-space destinations, like Mars.  

Small Satellite Technology

Our latest generation of small satellite technology represents a new way of advancing scientific research and reducing costs. These small sats are part of a technology demonstration that were deployed from the International Space Station in December 2016.   

Technology Development Organization

In 2013, we created a standalone technology development organization at NASA. Why? This new organization was an outgrowth of President Obama’s recognition of the critical role that space technology and innovation will play in enabling both future space missions and bettering life on Earth. The President’s most recent budget request included $4 million per year for our Centennial Challenges prizes. This program seeks innovations from diverse and non-traditional sources and competitors are not supported by government funding. Awards are only made to successful teams when the challenges are met. Throughout this administration (2009 – 2016), more than $6.5 million has been awarded to winners. 


Did you know that many technologies originally designed for space exploration are now being used by the general public? Yes, there’s space in your life! We have a long history of transferring technology to the private sector, things we like to call NASA Spinoffs. From enriched baby formula, to digital camera sensors…you may be surprised where this technology came from. 

 Space Station Extended to 2024

In 2014, the Obama Administration announced that the United States would support the extension of the International Space Station to at least 2024. This gave the station a decade to continue its already fruitful microgravity research mission. This offered scientists and engineers the time they need to ensure the future of exploration, scientific discoveries and economic development.  

Year in Space Mission

Former NASA astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko spent a year in space to help us understand the impacts of long-duration spaceflight on the human body. The studies performed throughout their stay will yield beneficial knowledge on the medical, psychological and biomedical challenges faced by astronauts that will one day travel to Mars. Scott Kelly was a particularly interesting candidate for the job, as he has a twin brother. While Scott spent a year on the International Space Station, his brother Mark spent the year on Earth. Comparing test results from both subjects will provide an even deeper understanding of the human body and how it reacts to the space environment.  

EPIC Earth Images

From one MILLION miles away, our EPIC camera on the Deep Space Climate Observatory (DSCOVR) satellite returned its first view of the entire sunlit side of Earth in 2015. Because of this spacecraft, you can now see a daily series of images of our home planet! These images are available 12 to 36 hours after they are acquired. 

James Webb Space Telescope

The James Webb Space Telescope represents a giant leap forward in our quest to understand the universe and our origins.  The successor to the Hubble Space Telescope, JWST is designed to examine every phase of cosmic history: from the first luminous glows after the Big Bang to the formation of galaxies, stars, and planets to the evolution of our own solar system. More: 

Green Aviation

Our commitment to advancing aeronautics has led to developments in today’s aviation that have made air travel safer than ever. In fact, every U.S. aircraft flying today and every U.S. air traffic control tower uses NASA-developed technology in some way. Streamlined aircraft bodies, quieter jet engines, techniques for preventing icing, drag-reducing winglets, lightweight composite structures, software tools to improve the flow of tens of thousands of aircraft through the sky, and so much more are an everyday part of flying thanks to our research that traces its origins back to the earliest days of aviation. Our green aviation technologies are dramatically reducing the environmental impact of aviation and improving its efficiency while maintaining safety in more crowded skies, and paving the way for revolutionary aircraft shapes and propulsion. 


History is about to repeat itself as the Quiet Supersonic Technology, or QueSST, concept  begins its design phase to become one of the newest generation of X-planes. Over the past seven decades, our nation’s best minds in aviation designed, built and flew a series of experimental airplanes to test the latest fanciful and practical ideas related to flight. Known as X-planes, we are again are preparing to put in the sky an array of new experimental aircraft, each intended to carry on the legacy of demonstrating advanced technologies that will push back the frontiers of aviation.  


Blazing the trail for safely integrating drones into the national airspace, we have been testing and researching uncrewed aircraft. The most recent “out of sight” tests are helping us solve the challenge of drones flying beyond the visual line of sight of their human operators without endangering other aircraft. 

Solar Dynamics Observatory

Our Solar Dynamics Observatory, which launched in 2010, observes the sun in unparalleled detail and is yet another mission designed to understand the space in which we live. In this image, the sun, our system’s only star seems to be sending us a message. A pair of giant filaments on the face of the sun form what appears to be an enormous arrow pointing to the right. If straightened out, each filament would be about as long as the sun’s diameter—1 million miles long. Such filaments are cooler clouds of solar material suspended above the sun’s surface by powerful magnetic forces. Filaments can float for days without much change, though they can also erupt, releasing solar material in a shower that either rains back down or escapes out into space, becoming a moving cloud known as a coronal mass ejection, or CME.  

Curiosity Launch and Landing

There are selfies and there are selfies—from a world more than 33 million miles away. When the Curiosity Rover launched on Nov. 6, 2011, to begin a 10-month journey to the Red Planet, who knew it would be so photogenic. Not only has Curiosity sent back beauty shots of itself, its imagery has increased our knowledge of Mars manyfold. But it’s not just a camera; onboard are an array of scientific instruments designed to analyze the Red Planet’s soil, rocks and chemical composition. 

Astronaut Applications

On Dec. 14, 2015, we announced that astronaut applications were open on USAJOBS. The window for applications closed on Feb. 18 with a record turnout! We received more than 18,300 applications from excited individuals from around the country, all hoping to join the 2017 astronaut class. This surpassed the more than 6,100 received in 2012, and the previous record of 8,000 applicants in 1978.  


Asteroids are a part of our solar system and in our quest to learn more about their origins, we sent the OSIRIS-Rex, the Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, to rendezvous with comet Bennu and return a sample of the comet to scientists here on Earth. Along the way, the mission will be multitasking during its two-year outbound cruise to search for elusive “Trojan” asteroids. Trojans are asteroids that are constant companions to planets in our solar system as they orbit the sun, remaining near a stable point 60 degrees in front of or behind the planet. 

 Habitable Zone Planets

In December 1995, the first exoplanet (a planet outside our solar system) was found. Since then, our Kepler mission has surveyed the Milky Way to verify 2,000+ exoplanets. On July 23, 2015, the Kepler mission confirmed the discovery of the first Earth-sized planet in the habitable zone. Not only that, but the planet orbits a sun very much like our own. 

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In commemoration of NASA’s Hubble Space Telescope completing its 100,000th orbit in its 18th year of exploration and discovery, scientists at the Space Telescope Science Institute in Baltimore, Md., have aimed Hubble to take a snapshot of a dazzling region of celestial birth and renewal.

Hubble peered into a small portion of the nebula near the star cluster NGC 2074 (upper, left). The region is a firestorm of raw stellar creation, perhaps triggered by a nearby supernova explosion. It lies about 170,000 light-years away near the Tarantula nebula, one of the most active star-forming regions in our Local Group of galaxies.

The three-dimensional-looking image reveals dramatic ridges and valleys of dust, serpent-head “pillars of creation,” and gaseous filaments glowing fiercely under torrential ultraviolet radiation. The region is on the edge of a dark molecular cloud that is an incubator for the birth of new stars.

The high-energy radiation blazing out from clusters of hot young stars already born in NGC 2074 is sculpting the wall of the nebula by slowly eroding it away. Another young cluster may be hidden beneath a circle of brilliant blue gas at center, bottom.

In this approximately 100-light-year-wide fantasy-like landscape, dark towers of dust rise above a glowing wall of gases on the surface of the molecular cloud. The seahorse-shaped pillar at lower, right is approximately 20 light-years long, roughly four times the distance between our Sun and the nearest star, Alpha Centauri.

The region is in the Large Magellanic Cloud (LMC), a satellite of our Milky Way galaxy. It is a fascinating laboratory for observing star-formation regions and their evolution. Dwarf galaxies like the LMC are considered to be the primitive building blocks of larger galaxies.

This representative color image was taken on August 10, 2008, with Hubble’s Wide Field Planetary Camera 2. Red shows emission from sulfur atoms, green from glowing hydrogen, and blue from glowing oxygen.

For additional information, contact:

Ray Villard / Cheryl Gundy / Donna Weaver
Space Telescope Science Institute, Baltimore, Md.
410-338-4514 / 410-338-4707 / 410-338-4493 / /

Mario Livio
Space Telescope Science Institute, Baltimore, Md.

Object Name: NGC 2074

Image Type: Astronomical

Credit: NASA, ESA, and M. Livio (STScI)

Time And Space

Hubble sees starbursts in Virgo

Although galaxy formation and evolution are still far from being fully understood, the conditions we see within certain galaxies – such as so-called starburst galaxies – can tell us a lot about how they have evolved over time. Starburst galaxies contain a region (or many regions) where stars are forming at such a breakneck rate that the galaxy is eating up its gas supply faster than it can be replenished!

NGC 4536 is such a galaxy, captured here in beautiful detail by the Hubble’s Wide Field Camera 3 (WFC3). Located roughly 50 million light-years away in the constellation of Virgo (The Virgin), it is a hub of extreme star formation. There are several different factors that can lead to such an ideal environment in which stars can form at such a rapid rate. Crucially, there has to be a sufficiently massive supply of gas. This might be acquired in a number of ways – for example by passing very close to another galaxy, in a full-blown galactic collision, or as a result of some event that forces lots of gas into a relatively small space.

Star formation leaves a few tell-tale fingerprints, so astronomers can tell where stars have been born. We know that starburst regions are rich in gas. Young stars in these extreme environments often live fast and die young, burning extremely hot and exhausting their gas supplies fairly quickly. These stars also emit huge amounts of intense ultraviolet light, which blasts the electrons off any atoms of hydrogen lurking nearby (a process called ionization), leaving behind often colorful clouds of ionized hydrogen (known in astronomer-speak as HII regions).

IMAGE….Although galaxy formation and evolution are still far from being fully understood, the conditions we see within certain galaxies – such as so-called starburst galaxies – can tell us a lot about how they have evolved over time. Starburst galaxies contain a region (or many regions) where stars are forming at such a breakneck rate that the galaxy is eating up its gas supply faster than it can be replenished! Credit ESA/Hubble & NASA

Astronomers discover mysterious alignment of black holes

Deep radio imaging by researchers in the University of Cape Town and University of the Western Cape, in South Africa, has revealed that supermassive black holes in a region of the distant universe are all spinning out radio jets in the same direction – most likely a result of primordial mass fluctuations in the early universe. The astronomers publish their results in a new paper in Monthly Notices of the Royal Astronomical Society.

The new result is the discovery – for the first time – of an alignment of the jets of galaxies over a large volume of space, a finding made possible by a three-year deep radio imaging survey of the radio waves coming from a region called ELAIS-N1 using the Giant Metrewave Radio Telescope (GMRT).

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Mostly Mute Monday: A GLIMPSE of the galaxy

“This data will enable scientists to build the most accurate model ever of star-formation, history and evolution within our galaxy, and understand the mechanism behind the origin of practically all the light in our Universe.”

There’s nothing quite like the plane of our Milky Way galaxy. Some 200-400 billion stars are located there, including our own Sun. From our vantage point within it, most of these are obscured by the dust lanes present within. But thanks to its views in infrared light, the Spitzer Space Telescope can glimpse not only all of the stars and the dust simultaneously, it can do it at an alarming resolution. Recently, NASA has put together a 360° panorama of more than 2,000,000 Spitzer images taken from 2003-2014, and I’ve gone and stitched them together into a single, 180,000-pixel-long viewable experience that shows less than 3% of the sky, but nearly 50% of its stars.


A 3D printed universe in your hand

3D-printing technology has been used to create everything from iPad stands to guitars to lawnmowers and cars. Now a physicist at the University of California, Riverside is using the technology to understand the universe – its structure, the evolution of cosmic structures within it, and galaxy formation.

“These problems in cosmology are very difficult to visualize, even using computer graphics,” said Miguel Aragón-Calvo, a visiting assistant researcher in the Department of Physics and Astronomy.  “By 3D-printing them I am able to interact directly with the models and ‘see’ the problem at once.  In some cases this results in ‘eureka’ moments.”

Recently, Aragón-Calvo was trying to develop an automated method to identify and track the cosmic web across time in computer simulations. By 3D-printing a simpler 2D simulation and assigning the third dimension to time he realized that this was in fact the solution to his problem.

“Tridimensional cosmic structures can be easily identified and tracked as four-dimensional objects where time is taken as another spatial variable,” he said.  “Even though I had visualized the cosmic web many times before in the computer screen, the solution only became obvious once I held the model in my hand.”

Watch the video about it here

Galaxy NGC 4214

Galaxy NGC 4214, pictured here in an image from the NASA/ESA Hubble Space Telescope’s newest camera, is an ideal location to study star formation and evolution. Dominating much of the galaxy is a huge glowing cloud of hydrogen gas in which new stars are being born. A heart-shaped hollow — possibly galaxy NGC 4214’s most eye-catching feature — can be seen at the centre of this. Inside this cavity lies a large cluster of massive, young stars ranging in temperature from 10 000 to 50 000 degrees Celsius. Their strong stellar winds are responsible for the creation of this bubble. These features have the effect of stemming any further star formation due to the subsequent lack of gas.

Credit: NASA, ESA and the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration. Acknowledgment: R. O’Connell (University of Virginia) and the WFC3 Scientific Oversight Committee


Stellar simulators

Astrophysicists at UCSB’s Kavli Institute for Theoretical Physics will use a supercomputer to explore the driving forces behind mass loss in massive stars

It’s an intricate process through which massive stars lose their gas as they evolve, and a more complete understanding could be just calculations away – if only those calculations didn’t take several millennia to run on normal computers.

Now, astrophysicists Matteo Cantiello and Yan-Fei Jiang of UC Santa Barbara’s Kavli Institute for Theoretical Physics (KITP) may find a way around that problem.

The pair have been awarded 120 million CPU hours over two years on the supercomputer Mira – the sixth-fastest computer in the world – through the Innovative and Novel Computational Impact on Theory and Experiment (INCITE) program, an initiative of the U.S. Department of Energy Office of Science. INCITE aims to accelerate scientific discoveries and technological innovations by awarding, on a competitive basis, time on supercomputers to researchers with large-scale, computationally intensive projects that address “grand challenges” in science and engineering.

“Access to Mira means that we will be able to run calculations that otherwise would take about 150,000 years to run on our laptops,” said Cantiello, an associate specialist at KITP.

Cantiello and Jiang will use their supercomputer time to run 3-D simulations of stellar interiors, in particular the outer envelopes of massive stars. Such calculations are an important tool to inform and improve the one-dimensional approximations used in stellar evolution modeling. The researchers aim to unravel the complex physics involved in the interplay among gas, radiation and magnetic fields in such stars – stellar bodies that later in life can explode to form black holes and neutron stars.

The physicists use grid-based Athena++ code – which has been carefully extended and tested by Jiang – to solve equations for the gas flow in the presence of magnetic fields (magnetohydrodynamics) and for how photons move in such environments and interact with the gas flow (radiative transfer). The code divides the huge calculations into small pieces that are sent to many different CPUs and are solved in parallel. With a staggering number of CPUs – 786,432 to be precise – Mira speeds up the process tremendously.

This research addresses an increasingly important problem: understanding the structure of massive stars and the nature of the process that makes them lose mass as they evolve. This includes both relatively steady winds and dramatic episodic mass loss eruptions.

Called stellar mass loss, this process has a decisive effect on the final fate of these objects. The type of supernova explosion that these stars undergo, as well as the type of remnants they leave behind (neutron stars, black holes or even no remnant at all), are intimately tied to their mass loss.

The study is particularly relevant in light of the recent detection of gravitational waves from LIGO (Laser Interferometer Gravitational-Wave Observatory). The discovery demonstrated the existence of stellar mass black holes orbiting so close to each other that eventually they can merge and produce the observed gravitational waves.

“Understanding how these black hole binary systems formed in the first place requires a better understanding of the structure and mass loss of their stellar progenitors,” explained Jiang, a postdoctoral fellow at KITP.

The implications of the work Cantiello and Jiang will perform on Mira also extend to broader fields of stellar evolution and galaxy formation, among others.

anonymous asked:

Imagine Dean, a freshman college student with piercings n tattoos n flair for math and Castiel an eccentric genius physics masters student who Dean often stalks but then they end up in the same lab n suddenly they're friends. Friends like; pushing each other to-solve complicated calculus quicker, running ten more laps than yesterday, winning hotdog eating contests, argue wormhole theorybetter,fucking each other in really tiny places, intensefrottage sessions in sociology section of the library:)

Mmm, yess. I’m picturing a sort of bizarre take on Good Will Hunting here. Dean likes testing the messy-haired grad student, loves showing off his quick wit and sharp mind. Cas, quiet but observant, can’t deny how badly he wants the cocky freshman. Their pillowtalk isn’t fluffy, mundane nonsense, but intellectual conjecture about the universe… and often Cas will draw equations with marker on Dean’s tattooed skin… tracing inked lines with theoretical formulas regarding quantum entanglement, both chuckling at the pun as they brush their entwined legs together. The day Cas presents his dissertation, “Kinematic Clues to the Formation and Evolution of Galaxies,” Dean shows up and asks harder questions on Cas’ methodology and critical analysis than his department professors. They drive each other nuts… and drive each other HARD. Am I right? ;)

Originally posted by holyhotdamnsweetbabyjesus

Originally posted by hrzone2

Dwarf Spiral Galaxy: NGC 4605

This bundle of bright stars and dark dust is a dwarf spiral galaxy known as NGC 4605, located around 16 million light-years away in the constellation of Ursa Major (The Great Bear). This galaxy’s spiral structure is not obvious from this image, but NGC 4605 is classified as an SBc type galaxy — meaning that it has sprawling, loosely wound arms and a bright bar of stars cutting through its centre. NGC 4605 is a member of the Messier 81 group of galaxies, a gathering of bright galaxies including its namesake Messier 81, and the well-known Messier 82. Galaxy groups like this usually contain around 50 galaxies, all loosely bound together by gravity. This group is famous for its unusual members, many of which formed from collisions between galaxies. With its somewhat unusual form, NGC 4605 fits in well with the family of perturbed galaxies in the M81 group, although the origin of its abnormal features is not yet clear. The Messier 81 group is one of the nearest groups to our own, the Local Group, which houses the Milky Way and some of its well-known neighbours, including the Andromeda Galaxy and the Magellanic Clouds. Galaxy groups provide environments where galaxies can evolve through interactions like collisions and mergers. These galaxy groups are then lumped together into even larger gatherings of galaxies known as clusters and superclusters. The Local and Messier 81 groups both belong to the Virgo Supercluster, a large and massive collection of some 100 galaxy groups and clusters. With so many galaxies swarming around, NGC 4605 may seem unremarkable. However, astronomers are using this galaxy to test our knowledge of stellar evolution. The newly-formed stars in NGC 4605 are being used to investigate how interactions between galaxies affect the formation, evolution, and behaviour of the stars within, how bright stellar nurseries come together to form stellar clusters and stellar associations, and how these stars evolve over time. And that’s not all — NGC 4605 is also proving to be a good testing ground for dark matter. Our theories on this hypothetical type of matter have had good success at describing how the Universe looks and behaves on a large scale — for example at the galaxy supercluster level — but when looking at individual galaxies, they have run into problems. Observations of NGC 4605 show that the way in which dark matter is spread throughout its halo is not quite as these models predict. While intriguing, observations in this area are still inconclusive, leaving astronomers to ponder over the contents of the Universe. Caption: Hubble Heritage Team


The birth of monsters

Just counting the number of galaxies in a patch of sky provides a way to test astronomers’ theories of galaxy formation and evolution. However, such a simple task becomes increasingly hard as astronomers attempt to count the more distant and fainter galaxies. It is further complicated by the fact that the brightest and easiest galaxies to observe – the most massive galaxies in the Universe – are rarer the further astronomers peer into the Universe’s past, whilst the more numerous less bright galaxies are even more difficult to find.

A team of astronomers, led by Karina Caputi of the Kapteyn Astronomical Institute at the University of Groningen, has now unearthed many distant galaxies that had escaped earlier scrutiny. They used images from the UltraVISTA (http://ultravista.​org/​) survey, one of six projects using VISTA to survey the sky at near-infrared wavelengths, and made a census of faint galaxies when the age of the Universe was between just 0.75 and 2.1 billion years old.

UltraVISTA has been imaging the same patch of sky, nearly four times the size of a full Moon, since December 2009. This is the largest patch of sky ever imaged to these depths at infrared wavelengths. The team combined these UltraVISTA observations with those from the NASA Spitzer Space Telescope, which probes the cosmos at even longer, mid-infrared wavelengths [1].

“We uncovered 574 new massive galaxies – the largest sample of such hidden galaxies in the early Universe ever assembled,” explains Karina Caputi. “Studying them allows us to answer a simple but important question: when did the first massive galaxies appear?”

Imaging the cosmos at near-infrared wavelengths allowed the astronomers to see objects that are both obscured by dust, and extremely distant [2], created when the Universe was just an infant.

The team discovered an explosion in the numbers of these galaxies in a very short amount of time. A large fraction of the massive galaxies [3] we now see around us in the nearby Universe were already formed just three billion years after the Big Bang.

“We found no evidence of these massive galaxies earlier than around one billion years after the Big Bang, so we’re confident that this is when the first massive galaxies must have formed,” concludes Henry Joy McCracken, a co-author on the paper [4].

In addition, the astronomers found that massive galaxies were more plentiful than had been thought. Galaxies that were previously hidden make up half of the total number of massive galaxies present when the Universe was between 1.1 and 1.5 billion years old [5]. These new results, however, contradict current models of how galaxies evolved in the early Universe, which do not predict any monster galaxies at these early times.

To complicate things further, if massive galaxies are unexpectedly dustier in the early Universe than astronomers predict then even UltraVISTA wouldn’t be able to detect them. If this is indeed the case, the currently-held picture of how galaxies formed in the early Universe may also require a complete overhaul.

The Atacama Large Millimeter/submillimeter Array (ALMA) will also search for these game-changing dusty galaxies. If they are found they will also serve as targets for ESO’s 39-metre European Extremely Large Telescope (E-ELT - http://eso.​org/​e-elt), which will enable detailed observations of some of the first ever galaxies.