radio astrophysics

How to Make Reading Astrophysics Papers More Interesting: Some Ideas

1. Mentally delete the “m” from all mentions of the word “mass.”

2. Assume that all mentions of dark matter actually refer to the villains from the Kirby video game franchise. This is literally my personal headcanon.

3. Turn all Messier catalogue numbers into names of different guns. Google already does that for you anyway! PRO TIP: Please put the word “galaxy” after all your searches for galaxy catalogue numbers. It will make you look less like a wingnut shopping for gifts.

4. Try to think of everything as if you’re a five year old. For instance, instead of “AGB star” think “stars that sneeze a lot.”

5. Whenever you see a log-log plot, get out a pencil and some paper and graph it the real way, without any logarithms.

6. Replace the non-evocative “parsec” with “3 light-years.” I mean, it’s not exact, but seriously, screw Megaparsecs. Who thought of that word anyway?! TECHNICAL NOTE: Parsecs are important because of the cosmological distance ladder. But, as I dislike both things being far away and climbing up ladders, I don’t really care.

7. Ignore any papers about the construction of the Thirty Meter Telescope. Actually, just avoid all discussions of the TMT all together. There, I just saved your faith in astronomy.

8. Sound out loud what you imagine the radio signals from the discussed objects would sound like. 

9. Replace all descriptions of black hole interactions with references to digestive bodily functions. 

10. Assume that all mentions of dark matter refer to…you know what, never mind. Just make all orbiting observatories into starships in a giant space-based MMORPG.

MYSTERIOUS BURSTS OF ENERGY DO COME FROM OUTER SPACE

Fast radio bursts present one of modern astronomy’s greatest mysteries: what or who in the universe is transmitting short bursts of radio energy across the cosmos?

Manisha Caleb, a PhD candidate at Australian National University, Swinburne University of Technology and the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), has confirmed that the mystery bursts of radio waves that astronomers have hunted for ten years really do come from outer space.

Ms. Caleb worked with Swinburne and University of Sydney colleagues to detect three of these fast radio bursts (FRBs) with the Molonglo radio telescope 40 km from Canberra.

Discovered almost 10 years ago at CSIRO’s Parkes radio telescope, fast radio bursts are millisecond-duration intense pulses of radio light that appear to be coming from vast distances. They are about a billion times more luminous than anything we have ever seen in our own Milky Way galaxy.

One potential explanation of the mystery is that they weren’t really coming from outer space, but were some form of local interference tricking astronomers into searching for new theories of their ‘impossible’ radio energy.

“Perhaps the most bizarre explanation for the FRBs is that they were alien transmissions,” says ARC Laureate Fellow Professor Matthew Bailes from Swinburne.

“Conventional single dish radio telescopes have difficulty establishing that transmissions originate beyond the Earth’s atmosphere,” says Swinburne’s Dr. Chris Flynn.

Molonglo Opens New Window on the Universe

In 2013 CAASTRO scientists and engineers realised that the Molonglo telescope’s unique architecture could place a minimum distance to the FRBs due to its enormous focal length. A massive re-engineering effort began, which is now opening a new window on the universe.

The Molonglo telescope has a huge collecting area (18,000 square metres) and a large field of view (eight square degrees on the sky), which makes it excellent for hunting for fast radio bursts.

Ms. Caleb’s project was to develop software to sift through the 1,000 terabytes (TB) of data produced each day. Her work paid off with the three new FRB discoveries.

“It is very exciting to see the University of Sydney’s Molonglo telescope making such important scientific discoveries by partnering with Swinburne’s expertise in supercomputing,” says Professor Anne Green of the University of Sydney.

Thanks to further funding from the Australian Research Council, the telescope will be improved even more to gain the ability to localise bursts to an individual galaxy.

“Figuring out where the bursts come from is the key to understanding what makes them. Only one burst has been linked to a specific galaxy,” Ms. Caleb says. “We expect Molonglo will do this for many more bursts.”

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Distant Quasars Show That Fundamental Constants Never Change

“From a physics perspective, it’s long been assumed that the fundamental constants and the laws of nature really are the same everywhere and at all times. However, one particular dimensionless constant, α, the ratio between the electric charge, the speed of light and the Planck constant, has been shown by a number of previous studies to show variations both the farther back in time we look and at different locations on the sky. However, new observations by a team working at Arecibo observatory, of the quasar PKS 1413+135, have placed a very tight constraint on the time variations, casting doubt on the previous findings. To only 1.3 parts in a million, the fundamental constant α once again appears to be truly constant.”

We assume that the fundamental constants are truly constant, but they don’t have to be. The speed of light is the same everywhere, but it could have been different elsewhere, either in space or in time. The same is true for other constants, like Planck’s constant, the gravitational constant, or even the fundamental charges or masses of particles. You might not think it’s likely, but the evidence indicated otherwise. Over the past 20 years, time variations and spatial variations in the fine structure constant, which determines the force of the electromagnetic coupling, have been observed to about 5 parts in a million in different locations and at different distances. It was a disputed but intriguing finding, but new evidence was just released conflicting with those results. Instead, the fundamental constant, α, once again appears to be truly constant, to better than 1.3 parts in a million, thanks to the new results from Arecibo.

There’s always more work to be done, but one of the greatest puzzling results from the astrophysical community might not be a puzzle after all!

The Poky Speed of Light

Radio frequencies like the frequencies of visible (and invisible) light are all an aspect of the same electromagnetic spectrum that in a vacuum travels at 299,792,458 meters or 186,282 miles per second. That’s appropriately 7 times around Earth’s equator in a single second.

As the bottom of the top chart states, Your mileage may vary. A good example of this is communicating with Mars. Depending where we are in our orbits relative to each other that 5.15 minutes can actually vary from 4 to as long as 24 minutes.

Keep looking up.

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Looking at the universe Naked- An Ontological Awakening.

It was Stephen Hawking who said:

We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the universe. That’s what makes us special.

The pictures showcase the universe in its cosmic brilliance. Spanning the entire electromagnetic spectrum, these images have been false- colored to help us perceive the universe that lies beyond our visual cognizance.

Courtesy: Chromoscope.

nature.com
Mysterious cosmic radio blasts traced to surprising source
Repeating bursts come from a faint, distant dwarf galaxy.

Astronomers have pinpointed the location of an enigmatic celestial object that spits out brief, but powerful, blasts of radio waves. Surprisingly, the source of these intermittent signals lies not in a bright galaxy but in a small, dim one, some 2.5 billion light-years from Earth.

The discovery begins to lift the curtain on the mystery of fast radio bursts, which have puzzled astronomers since they first described the signals in 20071. This detection has really broken open the gates of a new realm of science and discovery,” says Sarah Burke-Spolaor, an astronomer at the National Radio Astronomy Observatory in Socorro, New Mexico, and West Virginia University in Morgantown. She spoke in Grapevine, Texas, at a meeting of the American Astronomical Society.

Fast radio bursts appear to come from beyond the Milky Way and crop up seemingly at random across the sky. Although they last just milliseconds, the radio blasts can emit as much power as 500 million Suns.

Continue Reading.

Before they accuse me of knowing everything (ideological purity yada yada ) why dont they talk to me about Ham Radio or Astrophysics beforehand or some shit I know fuck all about. Instead they picked class struggle and proletarian revolution and, no, unfortunately for a you Im sorry but its a my most favourite thing ever and communism makes me feel glowy inside.

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Ultra-deep radio telescope captures what Hubble can’t

“Hubble can only expose visible and near-infrared light; it can only see stars. But there’s much more to the Universe. Most of the normal matter in the Universe is present in the forms of plasma and neutral gas, not stars. Although Hubble cannot see this gas, it emits light nonetheless, just at longer (radio) wavelengths.”

The Hubble Ultra Deep Field and its successor images represent humanity’s deepest views of the stars in our Universe. But there’s more to the Universe than just stars; even the normal matter in the Universe is more commonly present in the forms of gas and plasma than in stars. Hubble can never image those so far away, since their wavelengths are too long. But the Atacama Large Millimetre/submillimetre Array (ALMA) can see exactly that. By tuning ALMA so that it was very sensitive to a particular emission feature at high redshift – a carbon monoxide (CO) emission line – astronomers were able to construct a radio deep field image at the same location where the Hubble Ultra Deep Field was. What they revealed was a composite image of the stars and gas, shown together for the first time, finding that the Universe’s neutral gas is in great abundance only at the highest of redshifts.

Find out what this teaches us about the distant Universe over on today’s Mostly Mute Monday!

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The cosmic gift of neutron stars: a live blog event

“These massive, collapsed entities are neutron stars, coming in at up to three times the mass of our Sun, yet are no bigger than a large city like Washington, D.C. They are some of the most extreme objects in our Universe, and they enable us to explore some amazing things…”

Neutron stars are some of the most extreme objects in the Universe: a ball of neutrons a few kilometers in diameter, but with more mass than the entire Sun in them. Their magnetic fields are around a trillion times as strong as our Sun’s, they rotate at around 2/3 the speed of light, and they arise from the catastrophic supernovae of some of the Universe’s most massive stars. Later today, Vicky Kaspi will give Perimeter Institute’s public lecture on neutron stars and the great cosmic gift that they are to us. I highly recommend following along on my live blog, a unique experience to see an informed, professional astrophysicist give commentary and extra detail to another’s professional talk!

Tune in at 7:00 PM ET / 4:00 PM PT and don’t miss it!

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RADIO-BURST DISCOVERY DEEPENS ASTROPHYSICS MYSTERY:
BRIEF PULSE DETECTED BY ARECIBO TELESCOPE
APPEARS TO COME FROM FAR BEYOND OUR GALAXY

The discovery of a split-second burst of radio waves by scientists using the Arecibo radio telescope in Puerto Rico provides important new evidence of mysterious pulses that appear to come from deep in outer space.

The finding by an international team of astronomers, published July 10 in The Astrophysical Journal, marks the first time that a so-called “fast radio burst” has been detected using an instrument other than the Parkes radio telescope in Australia. Scientists using the Parkes Observatory have recorded a handful of such events, but the lack of any similar findings by other facilities had led to speculation that the Australian instrument might have been picking up signals originating from sources on or near Earth.

“Our result is important because it eliminates any doubt that these radio bursts are truly of cosmic origin,” said Victoria Kaspi, an astrophysics professor at McGill University in Montreal and Principal Investigator for the pulsar-survey project that detected this fast radio burst. “The radio waves show every sign of having come from far outside our galaxy – a really exciting prospect.”

Exactly what may be causing such radio bursts represents a major new enigma for astrophysicists. Possibilities include a range of exotic astrophysical objects, such as evaporating black holes, mergers of neutron stars, or flares from magnetars – a type of neutron star with extremely powerful magnetic fields.

“Another possibility is that they are bursts much brighter than the giant pulses seen from some pulsars,” notes James Cordes, a professor of astronomy at Cornell University and co-author of the new study.

The unusual pulse was detected on Nov. 2, 2012, at the Arecibo Observatory, a National Science Foundation-sponsored facility that boasts the world’s largest and most sensitive radio telescope, with a radio-mirror dish spanning 305 meters and covering about 20 acres.

While fast radio bursts last just a few thousandths of a second and have rarely been detected, the international team of scientists reporting the Arecibo finding confirm previous estimates that these strange cosmic bursts occur roughly 10,000 times a day over the whole sky. This astonishingly large number is inferred by calculating how much sky was observed, and for how long, in order to make the few detections that have so far been reported.

“The brightness and duration of this event, and the inferred rate at which these bursts occur, are all consistent with the properties of the bursts previously detected by the Parkes telescope in Australia,” said Laura Spitler, lead author of the new paper. Dr. Spitler, now a postdoctoral researcher at the Max Planck Institute for Radio Astronomy in Bonn, Germany, was a PhD student at Cornell when the research work began.

The bursts appear to be coming from beyond the Milky Way galaxy based on measurement of an effect known as plasma dispersion. Pulses that travel through the cosmos are distinguished from man-made interference by the effect of interstellar electrons, which cause radio waves to travel more slowly at lower radio frequencies. The burst detected by the Arecibo telescope has three times the maximum dispersion measure that would be expected from a source within the galaxy, the scientists report.

The discovery was made as part of the Pulsar Arecibo L-Band Feed Array (PALFA) survey, which aims to find a large sample of pulsars and to discover rare objects useful for probing fundamental aspects of neutron star physics and testing theories of gravitational physics.

Efforts are now under way to detect radio bursts using radio telescopes that can observe broad swaths of the sky to help identify them. Telescopes under construction in Australia and South Africa as well as the CHIME telescope in Canada have the potential to detect fast radio bursts; astronomers say these and other new facilities could pave the way for many more discoveries and a better understanding of this mysterious cosmic phenomenon.

Watch on scientiflix.com

Neil deGrasse Tyson: There Is No Center of the Universe

If the universe is expanding, can we use the direction of the expansion to determine the center of the universe, i.e., where the Big Bang happened? In a word, “No.” Find out why when astrophysicist Neil deGrasse Tyson and comic co-host Eugene Mirman answer a fan’s Cosmic Query in this StarTalk Radio “Behind the Scenes” video.

via Star Talk Radio.