Chandra Archives

November 20, 2013December 23, 2015 by Nancy Atkinson

Best Evidence Yet for a High-Energy Jet Emanating from the Milky Way’s Black Hole

A composite image in X-ray and radio showing a likely candidate for a jet emanating from the supermassive black hole at the center of the Milky Way. X-ray: NASA/CXC/UCLA/Z.Li et al; Radio: NRAO/VLA

Jets of high energy particles emanating from a black hole have been detected plenty of times before, but in other galaxies, that is — not from the supermassive black hole at the center of the Milky Way, known as Sagittarius A* (Sgr A*). Previous studies and other evidence suggested that perhaps there were jets – or ghosts of past jets – but many findings and studies often contradicted each other, and none were considered definitive.

Now, astronomers using Chandra X-ray Observatory and the Very Large Array (VLA) radio telescope have found strong evidence Sgr A* is producing a jet of high-energy particles.

“For decades astronomers have looked for a jet associated with the Milky Way’s black hole. Our new observations make the strongest case yet for such a jet,” said Zhiyuan Li of Nanjing University in China, lead author of a study in The Astrophysical Journal.

The supermassive black hole at the center of the Milky Way is about four million times more massive than our Sun and lies about 26,000 light-years from Earth.

While the common notion is that black holes inhale and ingest everything that comes their way, that’s not always true. Sometimes they reject small portions of incoming mass, pushing it away in the form of a powerful jet, and many times a pair of jets. These jets also feed the surroundings, releasing both mass and energy and likely play important roles in regulating the rate of formation of new stars.

Sgr A* is presently known to be consuming very little material, and so the jet is weak, making it difficult to detect. Astronomers don’t see another jet “shooting” in the opposite direction but that may be because of gas or dust blocking the line of sight from Earth or a lack of material to fuel the jet. Or there may be just a single jet.

“We were very eager to find a jet from Sgr A* because it tells us the direction of the black hole’s spin axis. This gives us important clues about the growth history of the black hole,” said Mark Morris of the University of California at Los Angeles, a co-author of the study.

The study shows the spin axis of Sgr A* is pointing in one direction, parallel to the rotation axis of the Milky Way, which indicates to astronomers that gas and dust have migrated steadily into Sgr A* over the past 10 billion years. If the Milky Way had collided with large galaxies in the recent past and their central black holes had merged with Sgr A*, the jet could point in any direction.

The jet appears to be running into gas near Sgr A*, producing X-rays detected by Chandra and radio emission observed by the VLA. The two key pieces of evidence for the jet are a straight line of X-ray emitting gas that points toward Sgr A* and a shock front — similar to a sonic boom — seen in radio data, where the jet appears to be striking the gas. Additionally, the energy signature, or spectrum, in X-rays of Sgr A* resembles that of jets coming from supermassive black holes in other galaxies.

The Chandra observations in this study were taken between September 1999 and March 2011, with a total exposure of about 17 days.

Source: Chandra

November 5, 2013December 23, 2015 by Elizabeth Howell

Chandra Infographic Shows Where The Color Comes From In Space Pictures

A part of the Small Magellanic Cloud galaxy is dazzling in this new view from NASA's Great Observatories. The Small Magellanic Cloud, or SMC, is a small galaxy about 200,000 light-years way that orbits our own Milky Way spiral galaxy. Credit: NASA.

For your daily space zing, check out an infographic recently highlighted on the Chandra X-ray Observatory’s Google+ page. Called “How to Color the Universe” (see it below), it explains why the colors we see from space telescope pictures are added in after the data is gathered.

In a nutshell, the information is recorded by the telescope in photons, which is sent down to Earth in binary code (1s and 0s). Software renders these numbers into images, then astronomers pick the colors to highlight what to show in the data.

“Colors play a very important role in communication information in astronomical images,” the infographic states. “Sometimes, colors are chosen to illustrate specific bands of light. There can be other motivating factors when picking colors, such as highlighting a particular feature or showcasing particular chemical elements.”

This multiwavelength image of the galaxy NGC 3627 contains X-rays from Chandra (blue), infrared data from Spitzer (red), and optical data from Hubble and the Very Large Telescope (yellow). Astronomers conducted a survey of 62 galaxies, which included NGC 3627, to study the supermassive black holes at their centers. Among this sample, 37 galaxies with X-ray sources are supermassive black hole candidates, and seven were not previously known. Confirming previous Chandra results, this study finds the fraction of galaxies hosting supermassive black holes is much higher than in optical searches for black holes that are relatively inactive.

It’s natural right now to think that astronomers are adding data where none exist, but Chandra’s public affairs employees (Kim Arcand and Megan Watzke) wrote a Huffington Post piece in September addressing this, too.

“Often, scientists choose colors to represent certain scientific phenomena such as structures that appear in one wavelength and not another. This might be why the planet is pink or the galaxy green. Or they might want to show where different elements like iron or magnesium are found in an object, and they can demonstrate this by assigning the sliver of light for each in different colors,” they wrote.

“In other instances, colors are picked to make an image the most pleasing or beautiful. In some of these instances, cries of the images being faked can erupt. But they are not fake, no matter what colors are used. We can’t see these data without scientific tools and processing. The color in these images enhances the data but does not alter them.”

If you have a high level of comfort manipulating images, Chandra offers a website to create images from raw data yourself, complete with a tutorial showing you how to do it.

October 29, 2013December 23, 2015 by Elizabeth Howell

Fluorescent and Starry: New Zinger Space Images From Chandra’s X-Ray Archives

Composite image of NGC 6946, a spiral galaxy 22 million light years from Earth. At least eight supernova have exploded in this galaxy in the past century, including three spotted by Chandra (purple). Optical data is also visible in red, yellow and cyan from the Gemini Observatory. Credit: X-ray: NASA/CXC/MSSL/R.Soria et al, Optical: AURA/Gemini OBs

You know that moment when you’re flipping through old digital pictures (on your computer or phone or whatever) and you realize there are some pretty awesome ones in there that you should share on social media? The Chandra X-Ray Observatory team also decided to plumb THEIR archive of astrophysical image magic, and came up with several beauties. Such as the one above this text.

Chandra has been in space since July 23, 1999 — yes, that’s well over 14 years ago — and is considered one of NASA’s telescopes under the “Great Observatories” programs. The other telescopes, by the way, are the Hubble Space Telescope, the Compton Gamma-Ray Observatory and the Spitzer Space Telescope. Hubble and Spitzer are also still active today.

Check out more from the new set of images below. There are eight all told, representing a tiny fraction of the unprocessed thousands of images available to the public in the Chandra Source Catalog.

The Elephant Trunk Nebula (IC 1396A) in X-ray, optical and infrared light. Astronomers believe they are seeing winds from large, young stars hitting cooler gas around it, possibly triggering new starbirth. X-ray data from Chandra is in purple, with optical data (red, green and blue) and infrared (orange and cyan). Credit: X-ray: NASA/CXC/PSU/Getman et al, Optical: DSS, Infrared: NASA/JPL-Caltech

3C353 looks a bit like a tadpole. In the center of this image is a galaxy powered by a supermassive black hole, which is transmitting energy across the expanse. Radiation is visible in X-rays from Chandra (purple) and radio from the Very Large Array (orange.) Credit: X-ray: NASA/CXC/Tokyo Institute of Technology/J.Kataoka et al, Radio: NRAO/VLA

SNR B0049-73.6 in X-ray and infrared light. Chandra's observations (purple) revealed that the explosion seen here was likely from a star's central core collapse. Infrared data from the 2MASS survey is also visible in red, green and blue. Credit: X-ray: NASA/CXC/Drew Univ/S.Hendrick et al, Infrared: 2MASS/UMass/IPAC-Caltech/NASA/NSF — SNR B0049-73.6 in X-ray and infrared light. Chandra’s observations (purple) revealed that the explosion seen here was likely from a star’s central core collapse. Infrared data from the 2MASS survey is also visible in red, green and blue. Credit: X-ray: NASA/CXC/Drew Univ/S.Hendrick et al, Infrared: 2MASS/UMass/IPAC-Caltech/NASA/NSF

NGC 4945, a galaxy 13 million light years from Earth. This galaxy is similar to the Milky Way, but has a more active supermassive black hole in the center (visible in white). Chandra X-ray data is in blue, overlaid on European Space Observatory optical information. Credit: X-ray: NASA/CXC/Univ degli Studi Roma Tre/A.Marinucci et al, Optical: ESO/VLT & NASA/STScI

3C 397, sometimes called G41.1-0.3, is a supernova leftover that looks a little funny. It's possible that the shape comes from heated remains of the star's shell bump into cooler gas surrounding it. X-ray data from Chandra is purple, infrared data from the Spitzer Space Telescope is yellow, and optical data from the Digitized Sky Survey is in red, green and blue. Credit: X-ray: NASA/CXC/Univ of Manitoba/S.Safi-Harb et al, Optical: DSS, Infrared: NASA/JPL-Caltech — 3C 397, sometimes called G41.1-0.3, is a supernova leftover that looks a little funny. It’s possible that the shape comes from heated remains of the star’s shell bump into cooler gas surrounding it. X-ray data from Chandra is purple, infrared data from the Spitzer Space Telescope is yellow, and optical data from the Digitized Sky Survey is in red, green and blue. Credit: X-ray: NASA/CXC/Univ of Manitoba/S.Safi-Harb et al, Optical: DSS, Infrared: NASA/JPL-Caltech

NGC 3576, a nebula 9,000 light-years from Earth, in X-ray (blue) and optical data. Chandra spotted evidence of strong winds coming from young stars in the nebula. Optical data from the European Space Observatory is shown in orange and yellow. Credit: X-ray: NASA/CXC/Penn State/L.Townsley et al, Optical: ESO/2.2m telescope

G266.2-1.2 in X-ray (purple) and optical light. Chandra spotted high-energy particles shooting out from this supernova leftover. The optical data comes from the Digitized Sky Survey and is available in red, green, and blue. Credit: X-ray: NASA/CXC/Morehead State Univ/T.Pannuti et al, Optical: DSS

September 25, 2013December 23, 2015 by Nancy Atkinson

Stars in this Jam-Packed Galaxy are 25 Times Closer Together than in the Milky Way

Galaxy M60-UCD1 is an ultra-compact dwarf galaxy, and is packed with an extraordinary number of stars. Credit: X-ray: NASA/CXC/MSU/J.Strader et al, Optical: NASA/STScI

Meet galaxy M60-UCD1. This is not your average, every day, ordinary galaxy. First of all, it’s what is known as an ‘ultra-compact dwarf galaxy,’ which – as the name implies — are unusually dense and small galaxies. Additionally, it is the most luminous known galaxy of its type and one of the most massive, weighing 200 million times more than our Sun. But M60-UCD1 is jam-packed with an extraordinary number of stars, making it the densest galaxy in the nearby Universe that we know of. Stars in M60-UCD1 are thought to be 25 times closer together than the stars in our galaxy.

Quick and easy access to neighboring star systems (if you lived there) might be your first thought. But remember, space is big, no matter where you are.

“Traveling from one star to another would be a lot easier in M60-UCD1 than it is in our galaxy,” said Jay Strader of Michigan State University in Lansing, first author of a paper describing these results. “But it would still take hundreds of years using present technology.”

Ultra-compact dwarf galaxies were discovered about a decade ago. They are typically about only 100 light years across compared to the 1,000 light years or more than other dwarf galaxies. Our Milky Way galaxy is 120,000 light-years across.

This graph shows where M60-UCD1 fits in as far as luminosity and size. Credit: Strader et al.

Strader said that what makes M60-UCD1 so remarkable is that about half of its mass is found within a radius of only about 80 light years. This would make the density of stars about 15,000 times greater than found in Earth’s neighborhood in the Milky Way.

“Our discovery of M60-UCD1 lends support to the idea that ultra-compact dwarfs could be stripped-down version of more massive galaxies,” Strader wrote in a post on the Chandra blog. “The first reason is its mass: we estimate that it contains about 400 million stars, far more than observed for even massive star clusters, and much closer to the galaxy regime. We also observe that M60-UCD1 has two “parts”: an inner, even denser core embedded in a more diffuse field of stars. This structure is not expected for a star cluster, but it’s a natural outcome of the tidal stripping process that could produce an ultra-compact dwarf.”

And so, this UCD is providing astronomers with clues to how these types of galaxies fit into the galactic evolutionary chain.

Additionally, this galaxy appears to have a central black hole, as Chandra X-ray Observatory reveal the presence of an X-ray source sitting right at the center.

While supermassive black holes are known to be common in the most massive galaxies, it is unknown whether they occur in less massive galaxies like M60-UCD1, Strader said.

“Further observations of M60-UCD1 and other ultra-compact dwarfs could confirm a new, significant population of massive black holes,” Strader said. “These masses of these black holes would be notable: while most central black holes in galaxies have only a fraction of a percent of the mass of their host galaxies, in ultra-compact dwarfs the black holes could be a full 10% of the mass of the dwarf. This is because so many of the dwarf’s outer stars have been stripped away, essentially boosting the contribution of the unaffected central black hole to the total mass of the galaxy.”

M60-UCD1 is located near a massive elliptical galaxy NGC 4649, also called M60, about 60 million light years from Earth. The galaxy was discovered with NASA’s Hubble Space Telescope and follow-up observations were done with NASA’s Chandra X-ray Observatory, the Keck Observatory in Hawaii, and the Multiple Mirror Telescope in Arizona.

Here’s the paper describing the discovery and the galaxy.

Sources: Chandra website, Chandra blog

August 29, 2013December 23, 2015 by Jason Major

Our Galaxy’s Supermassive Black Hole is a Sloppy Eater

X-ray and infrared image of Sgr A*, the supermassive black hole in the center of the Milky Way

Like most galaxies, our Milky Way has a dark monster in its middle: an enormous black hole with the mass of 4 million Suns inexorably dragging in anything that comes near. But even at this scale, a supermassive black hole like Sgr A* doesn’t actually consume everything that it gets its gravitational claws on — thanks to the Chandra X-ray Observatory, we now know that our SMB is a sloppy eater and most of the material it pulls in gets spit right back out into space.

(Perhaps it should be called the Cookie Monster in the middle.*)

New Chandra images of supermassive black hole Sagittarius A*, located about 26,000 light-years from Earth, indicate that less than 1% of the gas initially within its gravitational grasp ever reaches the event horizon. Instead, much of the gas is ejected before it gets near the event horizon and has a chance to brighten in x-ray emissions.

The new findings are the result of one of the longest campaigns ever performed with Chandra, with observations made over 5 weeks’ time in 2012.

“This new Chandra image is one of the coolest I’ve ever seen,” said study co-author Sera Markoff of the University of Amsterdam in the Netherlands. “We’re watching Sgr A* capture hot gas ejected by nearby stars, and funnel it in towards its event horizon.”

As it turns out, the wholesale ejection of gas is necessary for our resident supermassive black hole to capture any at all. It’s a physics trade-off.

“Most of the gas must be thrown out so that a small amount can reach the black hole”, said co-author Feng Yuan of Shanghai Astronomical Observatory in China. “Contrary to what some people think, black holes do not actually devour everything that’s pulled towards them. Sgr A* is apparently finding much of its food hard to swallow.”

If it seems odd that such a massive black hole would have problems slurping up gas, there are a couple of reasons for this.

One is pure Newtonian physics: to plunge over the event horizon, material captured — and subsequently accelerated — by a black hole must first lose heat and momentum. The ejection of the majority of matter allows this to occur.

The other is the nature of the environment in the black hole’s vicinity. The gas available to Sgr A* is very diffuse and super-hot, so it is hard for the black hole to capture and swallow it. Other more x-ray-bright black holes that power quasars and produce huge amounts of radiation have much cooler and denser gas reservoirs.

Located relatively nearby, Sgr A* offers scientists an unprecedented view of the feeding behaviors of such an exotic astronomical object. Currently a gas cloud several times the mass of Earth, first spotted in 2011, is moving closer and closer to Sgr A* and is expected to be ripped apart and partially consumed in the coming weeks. Astronomers are eagerly awaiting the results.

“Sgr A* is one of very few black holes close enough for us to actually witness this process,” said Q. Daniel Wang of the University of Massachusetts at Amherst, who led the study.

Watch Black Holes: Monsters of the Cosmos

Source: Chandra press release. Read the team’s paper here.

Image credits: X-ray: NASA/UMass/D.Wang et al., IR: NASA/STScI

_________________

*Any resemblance of Sgr A* to an actual Muppet, real or fictitious, is purely coincidental.

July 29, 2013December 23, 2015 by Nancy Atkinson

“Blue” Exoplanet Now Seen in X-rays for the First Time

This graphic depicts HD 189733b, the first exoplanet caught passing in front of its parent star in X-rays. Credit: X-ray: NASA/CXC/SAO/K.Poppenhaeger et al; Illustration: NASA/CXC/M.Weiss.

In the medical field, X-rays are used for finding and diagnosing all sorts of ailments hidden inside the body; in astronomy X-rays can also be used to study obscured objects like pulsars and black holes. Now, for the first time, X-rays have been used to study another object in space that tends to be difficult to spot: an extra solar planet. The Chandra X-ray Observatory and the XMM Newton Observatory combined their X-ray super powers to look at an exoplanet passing in front of its parent star.

This is not a new detection of an exoplanet – this same exoplanet, named HD 189733b has been one of the most-observed planets orbiting another star, and was recently in the news for Hubble confirming the planet’s ocean-blue atmosphere and the likelihood of having glass raining down on the planet.

But being able to see the exoplanet in X-rays is good news for future studies and perhaps even detections of planets around other stars.

“Thousands of planet candidates have been seen to transit in only optical light,” said Katja Poppenhaeger of Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., who led the new study, which will be published in the Aug. 10 edition of The Astrophysical Journal. “Finally being able to study one in X-rays is important because it reveals new information about the properties of an exoplanet.”

Artist’s impression of the deep blue planet HD 189733b, based on observations from the Hubble Space Telescope. Credit: NASA/ESA.

HD 189733b is a Jupiter-sized extrasolar planet orbiting a yellow dwarf star that is in a binary system called HD 189733 in the constellation of Vulpecula, near the Dumbell Nebula, approximately 62 light years from Earth.

This huge gas giant orbits very close to its host star and gets blasted with X-rays from its star — tens of thousands of times stronger than the Earth receives from the Sun — and endures wild temperature swings, reaching scorching temperatures of over 1,000 degrees Celsius. Astronomers say it likely rains glass (silicates) – sideways — in howling 7,000 kilometer-per-hour winds.

But it is relatively close to Earth, and so it has been oft-studied by many other space and ground-based telescopes.

In a blog post, Poppenhaeger said she was inspired by the launch of the Kepler telescope, and wondered if exoplanets could be seen in X-rays. She was excited when she found archived data from XMM Newton showing a fifteen hour long observation of the star HD 189733 and the “Hot Jupiter” HD 189733b was crossing in front of the star during that observation.

But the light curve was disappointing, she said. “The star is magnetically active, meaning that its corona is bright and flickering, so its X-ray light curve showed lots of scatter. Looking for a transit signal in this light curve was like trying to hear a whisper in a noisy pub,” Poppenhaeger wrote.

She knew with more data, the transit signal would be clearer, so she applied for – and got – time on Chandra to observe this exoplanet.

She combined the data from all the observations and was finally successful. “I could detect the transit of the planet in X-rays,” Poppenhaeger said. “What surprised me was how deep the transit was: The planet swallowed about 6-8% of the X-ray light from the star, while it only blocked 2.4% of the starlight at optical wavelengths. That means that the planet’s atmosphere blocks X-rays at altitudes of more than 60,000 km above its optical radius – a 75% larger radius in X-rays!”

That means that the outer atmosphere has to be heated up to about 20,000 K to sustain itself at such high altitudes. Additionally, the planet loses its atmosphere about 40% faster than thought before.

Poppenhaeger said she and her colleagues will test more X-ray observations of other similar planets such as CoRoT-2b to learn more about how stars can affect a planet’s atmosphere.

Read the paper here.

Sources: Chandra, Chandra Blog.

May 1, 2013December 23, 2015 by Tammy Plotner

NGC 6240: Gigantic Hot Gas Cloud Sheaths Colliding Galaxies

Credit: X-ray (NASA/CXC/SAO/E.Nardini et al); Optical (NASA/STScI)

Looking almost like a cosmic hyacinth, this image is anything but a cool, Spring flower… it’s a portrait of an enormous gas cloud radiating at more than seven million degrees Kelvin and enveloping two merging spiral galaxies. This combined image glows in purple from the Chandra X-ray information and is embellished with optical sets from the Hubble Space Telescope. It flows across 300,000 light years of space and contains the mass of ten billion Suns. Where did it come from? Researchers theorize it was caused by a rush of star formation which may have lasted as long as 200 million years.

What we’re looking at is known in astronomical terms as a “halo” – a glorious crown which is located in a galactic system cataloged as NGC 6240. This is the site of an interacting set of of spiral galaxies which have a close resemblance to our own Milky Way – each with a supermassive black hole for a heart. It is surmised the black holes are headed towards each other and may one day combine to create an even more incredible black hole.

However, that’s not all this image reveals. Not only is this pair of galaxies combining, but the very act of their mating has caused the collective gases to be “violently stirred up”. The action has caused an eruption of starbirth which may have stretched across a period of at least 200 million years. This wasn’t a quiet event… During that time, the most massive of the stars fled the stellar nursery, evolving at a rapid pace and blowing out as supernovae events. According to the news release, the astronomers who studied this system argue that the rapid pace of the supernovae may have expelled copious quantities of significant elements such as oxygen, neon, magnesium and silicon into the gaseous envelope created by the galactic interaction. Their findings show this enriched gas may have expanded into and combined with the already present cooler gas.

Now, enter a long time frame. While there was an extensive era of star formation, there may have been more dramatic, shorter bursts of stellar creation. “For example, the most recent burst of star formation lasted for about five million years and occurred about 20 million years ago in Earth’s time frame.” say the paper’s authors. However, they are also quick to point out that the quick thrusts of star formation may not have been the sole producer of the hot gases.

Perhaps one day these two interactive spiral galaxies will finish their performance… ending up as rich, young elliptical galaxy. It’s an act which will take millions of years to complete. Will the gas hang around – or will it be lost in space? No matter what the final answer is, the image gives us a first-hand opportunity to observe an event which dominated the early Universe. It was a time “when galaxies were much closer together and merged more often.”

Original Story Source: Chandra X-Ray Observatory News Release.

April 3, 2013December 23, 2015 by Nancy Atkinson

NASA’s Great Observatories Provide a Sparkly New View of the Small Magellanic Cloud

This is just pretty! NASA’s Great Observatories — the Hubble Space Telescope, the Chandra X-Ray Observatory and the Spitzer Infrared Telescope — have combined forces to create this new image of the Small Magellanic Cloud. The SMC is one of the Milky Way’s closest galactic neighbors. Even though it is a small, or so-called dwarf galaxy, the SMC is so bright that it is visible to the unaided eye from the Southern Hemisphere and near the equator.

What did it take to create this image? Let’s take a look at the images from each of the observatories:

The Small Magellenic Cloud in X-Ray from the Chandra X-Ray Observatory. Credit: NASA.

The Small Magellenic Cloud in infrared, from the Spitzer Infrared Telescope. Credit: NASA.

The Small Magellenic Cloud as seen in optical wavelengths from the Hubble Space Telescope. Credit: NASA.

The various colors represent wavelengths of light across a broad spectrum. X-rays from NASA’s Chandra X-ray Observatory are shown in purple; visible-light from NASA’s Hubble Space Telescope is colored red, green and blue; and infrared observations from NASA’s Spitzer Space Telescope are also represented in red.

The three telescopes highlight different aspects of this lively stellar community. Winds and radiation from massive stars located in the central, disco-ball-like cluster of stars, called NGC 602a, have swept away surrounding material, clearing an opening in the star-forming cloud.

Find out more at this page from Chandra, and this one from JPL.

March 26, 2013April 26, 2016 by Jason Major

Book Review: Your Ticket to the Universe

Your Ticket to the Universe: A Guide to Exploring the Cosmos (Available April 2)

Your Ticket to the Universe is full of images and graphics of astronomical wonders.

Every once in a while an astronomy book comes out that combines stunning high-definition images from the world’s most advanced telescopes, comprehensive descriptions of cosmic objects that are both approachable and easy to understand (but not overly simplistic) and a gorgeous layout that makes every page spread visually exciting and enjoyable.

This is one of those books.

Your Ticket to the Universe: A Guide to Exploring the Cosmos is a wonderful astronomy book by Kimberly K. Arcand and Megan Watzke, media coordinator and press officer for NASA’s Chandra X-ray Observatory, respectively. Published by Smithsonian Books, it features 240 pages of gorgeous glossy images from space exploration missions, from the “backyard” of our own Solar System to the more exotic environments found throughout the Galaxy… and even beyond to the very edges of the visible Universe itself.

Find out how you can win a copy of this book here!

As members of the Chandra team, headquartered at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, Kim and Megan have long had firsthand experience with incredible astronomical images — they previously designed and coordinated the internationally-acclaimed From Earth to the Universe and From Earth to the Solar System photo installation projects, which helped set up presentations of space exploration images in public locations around the world.

Your Ticket to the Universe features images from some of the most recent missions - like MSL! — *Your Ticket to the Universe* even features images from some of the most recent missions – like MSL!

Your Ticket to the Universe takes such impressive images — from telescopes and observatories like Hubble, Spitzer, SDO, Chandra, Cassini, GOES, VLT, and many others, as well as from talented photographers on Earth and in orbit aboard the ISS — and puts them right into your hands, along with in-depth descriptions that are comprehensive yet accessible to even the most casual fans of space exploration.

This is my favorite kind of astronomy book. Although I look at images like the ones in Your Ticket to the Universe online every day, there’s something special about having them physically in front of you in print — and well-written text that can be understood by everyone is crucial, in my opinion, as it means a book may very well become an inspiration to a whole new generation of scientists and explorers.

“The sky belongs to everyone. That’s the premise of this guidebook to the Universe. You don’t need a medical degree to know when you’re sick or a doctorate in literature to appreciate a novel. In the same spirit, even those of us who don’t have advanced degrees in astronomy can gain access to all the wonder and experience that the Universe has to offer.”

Kim K. Arcand holds a copy of her book during a presentation at the Skyscrapers Astronomical Society of Rhode Island — Author Kimberly K. Arcand holds a copy of her book during a presentation at the Skyscrapers Astronomical Society of Rhode Island

I’ve had the pleasure of meeting co-author Kimberly Arcand on several occasions — I attended high school with her husband — and her knowledge about astronomy imaging as well as her ability to present it in an understandable way is truly impressive, to say the least. She’s quite an enthusiastic ambassador for space exploration, and Your Ticket to the Universe only serves to further demonstrate that.

I highly recommend it for anyone who finds our Universe fascinating.

Your Ticket to the Universe will be available online starting April 2 at Smithsonian Books, or you can pre-order a copy at Barnes & Noble or on Amazon.com. Don’t explore the cosmos without it!

February 15, 2013December 23, 2015 by Jason Major

Galactic Gas Cloud Could Help Spot Hidden Black Holes

Illustration of gas cloud G2 approaching Sgr A* . Our central supermassive black hole periodically snacks on clouds and other material like this. That gives off X-rays and other emissions. (ESO/MPE/M.Schartmann/J.Major)

The heart of our Milky Way galaxy is an exotic place. It’s swarming with gigantic stars, showered by lethal blasts of high-energy radiation and a veritable cul-de-sac for the most enigmatic stellar corpses known to science: black holes. And at the center of the whole mélange is the granddaddy of all the black holes in the galaxy — Sagittarius A*, a supermassive monster with 4 million times more mass than the Sun packed into an area smaller than the orbit of Mercury.

Sgr A* dominates the core of the Milky Way with its powerful gravity, trapping giant stars into breakneck orbits and actively feeding on anything that comes close enough. Recently astronomers have been watching the movement of a large cloud of gas that’s caught in the pull of Sgr A* — they’re eager to see what exactly will happen once the cloud (designated G2) enters the black hole’s dining room… it will, in essence, be the first time anyone watches a black hole eat.

But before the dinner bell rings — estimated to be sometime this September — the cloud still has to cover a lot of space. Some scientists are now suggesting that G2’s trip through the crowded galactic nucleus could highlight the locations of other smaller black holes in the area, revealing their hiding places as it passes.

In a new paper titled “G2 can Illuminate the Black Hole Population near the Galactic Center” researchers from Columbia University in New York City and the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Massachusetts propose that G2, a cloud of cool ionized gas over three times more massive than Earth, will likely encounter both neutron stars and other black holes on its way around (and/or into) SMBH Sgr A*.

*Estimated number of stellar-mass black holes to be encountered by G2 along its trajectory (Bartos et al.)*

The team notes that there are estimated to be around 20,000 stellar-mass black holes and about as many neutron stars in the central parsec of the galaxy. (A parsec is equal to 3.26 light-years, or 30.9 trillion km. In astronomical scale it’s just over 3/4 the way to the nearest star from the Sun.) In addition there may also be an unknown number of intermediate-mass black holes lurking within the same area.

These ultra-dense stellar remains are drawn to the center region of the galaxy due to the effects of dynamical friction — drag, if you will — as they move through the interstellar material.

Of course, unless black holes are feeding and actively throwing out excess gobs of hot energy and matter due to their sloppy eating habits, they are very nearly impossible to find. But as G2 is observed moving along its elliptical path toward Sgr A*, it could very well encounter a small number of stellar- and intermediate-mass black holes and neutron stars. According to the research team, such interactions may be visible with X-ray spotting spacecraft like NASA’s Chandra and NuSTAR.

*NuSTAR X-ray image of a flare emitted by Sgr A* in July 2012 (NASA/JPL-Caltech)*

The chances of G2 encountering black holes and interacting with them in such a way as to produce bright enough x-ray flares that can be detected depends upon a lot of variables, like the angles of interaction, the relative velocities of the gas cloud and black holes, the resulting accretion rates of in-falling cloud matter, and the temperature of the accretion material. In addition, any observations must be made at the right time and for long enough a duration to capture an interaction (or possibly multiple interactions simultaneously) yet also be able to discern them from any background X-ray sources.

Still, according to the researchers such observations would be important as they could provide valuable information on galactic evolution, and shed further insight into the behavior of black holes.

Read the full report here, and watch an ESO news video about the anticipated behavior of the G2 gas cloud around the SMBH Sgr A* below:

This research was conducted by Imre Bartos, Zoltán Haiman, and Bence Kocsis of Columbia University and Szabolcs Márka of the Harvard-Smithsonian Center for Astrophysics.