Pulsars are extreme objects. They’re what’s left over when a massive star collapses on itself and explodes as a supernova. This creates a neutron star. Neutron stars spin, and some of them emit radiation. When they emit radiation from their poles that we can see, we call them pulsars.Continue reading “Spider Pulsars are Tearing Apart Stars in the Omega Cluster”
New images that combine data from NASA’s Chandra X-ray Observatory and the James Webb Space Telescope (JWST) JWST have just been released! The images feature four iconic astronomical objects, showcasing the capabilities of these observatories by combining light in the visible, infrared, and X-ray wavelengths. These include the NGC 346 star cluster located in the Small Magellanic Cloud (SMC), the NGC 1672 spiral galaxy, the Eagle Nebula (Messier 16, or M16), and the spiral galaxy Messier 74 (aka. the Phantom Galaxy).
These objects were made famous by the venerable Hubble Space Telescope, which took pictures of them between 1995 and 2005. Since it commenced operations, the JWST has conducted follow-up observations that provided a sharper view of these objects that captured additional features. Hubble and the JWST even teamed up to provide a multi-wavelength view of the Phantom Galaxy last year. By adding Chandra’s famed X-ray imaging capabilities to Webb’s sensitivity and infrared light, these latest images provide a new glimpse of these objects, revealing both faint and more energetic and powerful features.Continue reading “Chandra and JWST Join Forces in a Stunning Series of Images”
The early Universe was swimming with dwarf galaxies only a few hundred million years after the Big Bang. They merged with each other over time, building larger and more massive galaxies. At the same time, the giant black holes inside these dwarfs merged, too.Continue reading “Supermassive Black Holes on a Collision Course”
NASA scientist have released images combining the early data from the James Webb Space Telescope with X-ray data taken with the Chandra Observatory. Besides their beauty, the images offer insights into the inner workings of some of the most complex astrophysical phenomena in the universe.Continue reading “Chandra’s X-ray Vision Combined With JWST Reveals Even More Details About the Universe”
At the heart of the more massive galaxies in the Universe, there are supermassive black holes (SMBHs) so powerful that they outshine all of the stars in their galactic disks. The core regions of these galaxies are known as Active Galactic Nuclei (AGN), or by their more popular-moniker “quasars.” The ongoing study of these objects has provided a testbed for General Relativity and revealed a great deal about the formation and evolution of galaxies and the large-scale structure of the Universe.
If there’s one thing astronomers have observed repeatedly, it is the fact that these massive black holes have massive appetites. In fact, a new survey of over 100 galaxies by the NASA Chandra X-ray Observatory has shown that some supermassive black holes can consume stars by the thousands! These results indicate that some SMBHs needed to consume amounts of stellar matter rarely (if ever) seen in the Universe to grow and reach the sizes that astronomers see today.Continue reading “In Some Places, Black Holes are Tearing Apart Thousands of Stars at a Time”
What’s better than two gigantic galaxies swirling into one another until they collide? How about three galaxies swirling into one another until they collide – and they all have supermassive black holes at their core to boot! Recently, a team led by Dr. Adi Foord of Stanford combed through data from the WISE mission and the Sloan Digital Sky Survey to search for instances of three galaxies colliding with one another. In all that data, they managed to find 7 separate systems that met those criteria.Continue reading “What Happens to Their Supermassive Black Holes When Galaxies Collide?”
Can black holes be famous? If they can, then the one at the heart of the M87 galaxy qualifies. And this famous black hole is emitting jets of material that travel at near the speed of light.Continue reading “M87’s Black Hole is Firing Out Jets that Travel 99% the Speed of Light”
When stars reach the end of their life cycle, many will blow off their outer layers in an explosive process known as a supernova. While astronomers have learned much about this phenomena, thanks to sophisticated instruments that are able to study them in multiple wavelengths, there is still a great deal that we don’t know about supernovae and their remnants.
For example, there are still unresolved questions about the mechanisms that power the resulting shock waves from a supernova. However, an international team of researchers recently used data obtained by the Chandra X-Ray Observatory of a nearby supernova (SN1987A) and new simulations to measure the temperature of the atoms in the resulting shock wave.Continue reading “Astronomers are Continuing to Watch the Shockwaves Expand from Supernova SN1987A, as they Crash Into the Surrounding Interstellar Medium”
Images of the Crab Nebula are always a treat because it has such intriguing and varied structure. Also, just knowing that this stellar explosion was witnessed and recorded by people on Earth more than 900 years ago (with the supernova visible to the naked eye for about two years) gives this nebula added fascination.
A new image just might be the biggest Crab Nebula treat ever, as five different observatories combined forces to create an incredibly detailed view, with stunning details of the nebula’s interior region.
Data from the five telescopes span nearly the entire breadth of the electromagnetic spectrum, from radio waves seen by the Karl G. Jansky Very Large Array (VLA) to the powerful X-ray glow as seen by the orbiting Chandra X-ray Observatory. And, in between that range of wavelengths, the Hubble Space Telescope’s crisp visible-light view, and the infrared perspective of the Spitzer Space Telescope.
The Crab is 6,500 light-years from Earth and spans about 10 light-years in diameter. The supernova that created it was first witnessed in 1054 A. D. At its center is a super-dense neutron star that is as massive as the Sun but with only the size of a small town. This pulsar rotates every 33 milliseconds, shooting out spinning lighthouse-like beams of radio waves and light. The pulsar can be seen as the bright dot at the center of the image.
Scientists say the nebula’s intricate shape is caused by a complex interplay of the pulsar, a fast-moving wind of particles coming from the pulsar, and material originally ejected by the supernova explosion and by the star itself before the explosion.
For this new image, the VLA, Hubble, and Chandra observations all were made at nearly the same time in November of 2012. A team of scientists led by Gloria Dubner of the Institute of Astronomy and Physics (IAFE), the National Council of Scientific Research (CONICET), and the University of Buenos Aires in Argentina then made a thorough analysis of the newly revealed details in a quest to gain new insights into the complex physics of the object. They are reporting their findings in the Astrophysical Journal (see the pre-print here).
About the central region, the team writes, “The new HST NIR [near infrared] image of the central region shows the well-known elliptical torus around the pulsar, composed of a series of concentric narrow features of variable intensity and width… The comparison of the radio and the X-ray emission distributions in the central region suggests the existence of a double-jet system from the pulsar, one detected in X-rays and the other in radio. None of them starts at the pulsar itself but in its environs.”
“Comparing these new images, made at different wavelengths, is providing us with a wealth of new detail about the Crab Nebula. Though the Crab has been studied extensively for years, we still have much to learn about it,” Dubner said.
An international team of scientists has discovered an enormous wave of hot gas rolling its way through the Perseus galaxy cluster. The wave is a giant version of what’s called a Kelvin-Helmholtz wave. They’re created when two fluids intersect at different velocities: for example, when wind blows over water.
In this instance, the wave was caused by a small galaxy cluster grazing the Perseus cluster, and setting off a chain of events lasting billions of years. The findings appear in a paper in the June 2017 issue of the journal Monthly Notices of the Royal Astronomical Society.
“The wave we’ve identified is associated with the flyby of a smaller cluster, which shows that the merger activity that produced these giant structures is still ongoing.” – Stephen Walker, NASA’s Goddard Space Flight Center.
“Perseus is one of the most massive nearby clusters and the brightest one in X-rays, so Chandra data provide us with unparalleled detail,” said lead scientist Stephen Walker at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The wave we’ve identified is associated with the flyby of a smaller cluster, which shows that the merger activity that produced these giant structures is still ongoing.”
The Perseus galaxy cluster, also known as Abell 426, is 240 million light years away, and is about 11 million light years across. It’s one of the most massive objects we know of, and it’s named after the Perseus constellation, which appears in the same part of the sky.
Galaxy clusters are the largest gravitationally-bound objects in the Universe. Most of the observable matter in galaxy clusters is gas. But the gas is super hot—tens of millions of degrees hot—which means it emits x-rays.
X-Ray observations of Perseus have revealed several features and structures in the gas structure of the cluster. Some of them are bubble-like features caused by the super-massive black hole (SMBH) in NGC 1275, the Perseus cluster’s central galaxy. Another of these features is known as “the bay.” The bay is a concave feature which couldn’t have been formed by the SMBH.
The bay is a puzzle because it doesn’t produce any emissions, which would be expected of something formed by a SMBH. The bay also doesn’t conform to models of how gas should behave in this situation.
The lead scientist behind the study is Stephen Walker at NASA’s Goddard Space Flight Center. Walker turned to the Chandra X-ray Observatory to help solve this puzzle. Existing Chandra images of the Perseus cluster were filtered in order to highlight the edges of structures, and to make any subtle details more visible.
These filtered and processed images were then compared to computer simulations of galaxy clusters merging. John ZuHone, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, has created an online catalog of these simulations.
“Galaxy cluster mergers represent the latest stage of structure formation in the cosmos.” -John ZuHone, Harvard-Smithsonian Center for Astrophysics.
“Galaxy cluster mergers represent the latest stage of structure formation in the cosmos. Hydrodynamic simulations of merging clusters allow us to produce features in the hot gas and tune physical parameters, such as the magnetic field. Then we can attempt to match the detailed characteristics of the structures we observe in X-rays.” -John ZuHone, Harvard-Smithsonian Center for Astrophysics.
One of the simulations matched what astronomers were seeing in Perseus. In it, a large cluster like Perseus had settled itself into two regions: a colder region of gas around 30 million degrees Celsius, and a hotter region of gas at almost 100 million degrees Celsius. In this model, a cluster smaller than Perseus, but about a thousand times more massive than the Milky Way passes close to Perseus, missing its center by about 650,000 light years.
That happened about 2.5 billion years ago, and it set off a chain of events still playing itself out.
The near miss caused a gravitational disturbance that created an expanding spiral of the colder gas. An enormous wave of gas has formed at the edge of the spiral of colder gas, where it intersects with the hotter gas. This is the Kelvin-Helmholtz wave seen in the images.
“We think the bay feature we see in Perseus is part of a Kelvin-Helmholtz wave, perhaps the largest one yet identified, that formed in much the same way as the simulation shows,” Walker said. “We have also identified similar features in two other galaxy clusters, Centaurus and Abell 1795.”
The study provided another benefit besides just spotting an impossibly enormous wave. It allowed the team to measure the magnetic properties of the Perseus cluster. The researchers discovered that the strength of the magnetic field in the cluster affected the size of the wave of gas. It the field is too strong, the waves don’t form at all, and if the magnetic field is too weak, then the waves would be even larger.
According to the team, there is no other known way to measure the magnetic field.