coming events volume 44 number 10 monthly meetings...
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COMING EVENTS MONTHLY MEETINGS
SUNDAY—7 PM October 28
Coming Events - Beyond the Horizon
Bruce Twarog Baker Wetlands Discovery
Center PUBLIC OBSERVING
OCTOBER 28 ~8:15 PM
DECEMBER 02 President
Rick Heschmeyer
[email protected] ALCOR
William Winkler [email protected]
NSN Coordinator Howard Edin
Report from the Officers Probably one of the oldest lines about the weather in the Midwest is If you don’t like the weather, wait a few minutes. At the start of our Sept. meet-ing, the skies were 85% over-cast; by 8:00 PM, the clouds were clearing and by 8:30, it was almost totally clear with a little cirrus. As a result, a few optimistic visitors got to view some of the more spectacular planetary sights in the sky before the moon came up over the horizon. Our next session after the Oct. 28 meeting should be almost identical sky
conditions moonwise and darker a lot earlier, so come on out and have a view, weather permitting. Our Sept. speaker, Gary Hug, gave an update on the status of the Farpoint 27-inch (pictured above). It has been overhauled to operate as a Newto-nian, its original design, with a realuminized mirror and a better CCD camera with less noise. It can now readily reach fainter than 23rd magnitude on a long exposure. A possible road trip by AAL to visit the observatory is under consideration. (A history of the mirror from its time at KU can be accessed at this link.) Next month, the club
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Volume 44 Number 10 October 2018
INSIDE THIS ISSUE
Officers (continued) 2
Galaxy Mystery 2
October Meeting Poster 3
NASA Space Place 4
Far Flung Galaxies 5
First Exomoon Discovered 6
Galaxy Mystery (continued) 7
Exomoon (continued) 7
Neutron Star (continued) 7
Neutron Star Uncovered 8
X-Ray Tail 9
Galactic One-Ring 10
October Night Sky 11
October Scene 12
In Memoriam—George Brenner 12
Of Local Interest KU Astronomers Probe Galaxy Mystery Galaxies like our own Milky Way are factories that use gravity to fashion new stars out of molecular hydrogen gas. “The Milky Way is turning gas into stars at about an average of the mass of the sun every year,” said Gregory Rudnick, pro-fessor of physics & astronomy at the University of Kansas. “The galaxy is filled with gas, and we’re constantly getting new gas from outside the galaxy. This gas falls into the galaxy under the force of gravity, gets formed into stars — and some of the gas gets blown back out of the galaxy.” But some galaxies have stopped this process of star formation, and astronomers have been hard-pressed to ex-plain why. “We see plenty of galaxies that don’t form stars,” Rudnick said. “For whatever reason, they don’t have much gas in them so they can’t make new stars. The big question is why. Why do some galaxies shut off? When they shut off, they’re left with the stars they already have, but they don’t make new ones.” A key to solving this puzzle may be a strange new class of galaxies about 6 billion light years from Earth that are in the process of violently expelling their own gas. Now, Rudnick has teamed up with scientists from around the U.S. to study these galaxies as a means to find out why some galaxies no longer have the gas necessary to form
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About the Astronomy Associates of Lawrence
The club is open to all people interested in sharing their love for astronomy. Beginning in Fall 2016, monthly meetings are typical-ly on the last Sunday of each month and often feature guest speakers, presentations by club members, and a chance to ex-
change amateur astronomy tips. These meetings and the public observing sessions that follow are scheduled at the Baker Wet-lands Discovery Center, south of Lawrence. All events and meetings are free and open to the public. Periodic star parties are
scheduled as well. For more information, please contact the club officers: President Rick Heschmeyer at
[email protected]; AlCor William Winkler at [email protected]; NSN Coordinator Howard Edin at how-
[email protected], or faculty advisor Prof. Bruce Twarog at [email protected]. Because of the flexibility of the schedule due to holidays and alternate events, it is always best to check the Web site for the exact Sundays when events are scheduled. The
information about AAL can be found at http://www.physics.ku.edu/AAL/
Copies of the Celestial Mechanic can also be found on the web at http://www.physics.ku.edu/AAL/newsletter
returns to a more astrophysical topic with a presentation on the Event Horizon Telescope, an ongoing project to image the black hole at the center of the Milky Way. The consortium of telescopes behind this project supposedly completed data col-lection at the end of 2017 and has been analyzing the very complex information ever since, with the possibility of a Nobel-Prize level result appearing in the news almost any day. If you’ve ever wondered how one can see a black hole, here’s your chance to find out. Again, the next meeting is Sunday, Oct. 28 at 7 PM.
On a more personal note, we were saddened to learn about the death of George Brenner, an AAL club member for over 10 years, who moved to the East coast a couple of years ago, while still maintaining his membership in the club long distance. George was an active and enthusiastic attendee to all club meetings and events while in Lawrence, regularly volunteering and setting up his personal telescope for use by the public at open observing events. His enthusiasm for astronomy and science was a reflection of his exceptional professional career, having been awarded the first Ph.D. degree in Pharmacolo-gy and Toxicology at KU in 1971 and spending over 40 years in academia as a professor and researcher. A full bio of George can be found on pg. 12.
PS. The line about the weather has been used in almost every area the country that experiences seasonal variations in con-ditions. It is usually attributed to Mark Twain, referring to the weather in New England. Any suggestions for improving the club or the newsletter are always welcome.
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new stars. Part of the process is to question recent conventional ideas about the cessation of star formation. “One of the ways people have come up with to shut off star formation in a galaxy is to explosively remove the gas through an active galactic nucleus,” Rudnick said. “Every galaxy, including our own, has a supermassive black hole at its center. As gas falls into the black hole, right before it hits the black hole, it gets super-hot, and the energy it gives off can actually blow out the rest of the gas from the galaxy. People like this idea because it’s a mechanism that’s energetic enough to do the job of ex-pelling all the gas from the galaxy.” However, in 2007 a team of astronomers discovered a set of “self-quenching” galaxies that have shut down star formation by some other mechanism. Rudnick subsequently joined this team, which has led a mul-tiyear investigation of these objects. “Our research has found this kind of galaxy that has gas being blown out of it at thou-sands of kilometers per second — that’s over 3,500 times faster than a jet plane — but there’s absolutely no evidence of any kind of gas falling into a black hole,” the KU researcher said. “So, there’s a question of whether or not that black-hole process is required or if there are other ways of doing it. You realize, ‘Wait a minute, the universe isn’t that simple.’ This could tell us really new and cool things about how galaxies evolve.”
With better images of the galaxies from the Hubble Space Telescope, Rudnick and his collaborators realized gas could be expelled from the galaxies purely by the concentrated light of the stars in the galaxies, with no need for any extra energy from gas falling onto the black hole. “Using HST, these fuzzy dots we saw before from our telescopes on the ground now showed these features that looked like a collision of galaxies — they had lots of streams of stars around. Most surprisingly, they were incredibly compact,” Rudnick said. “The Milky Way has all its stars and gas spread out over 100,000 light years, meaning it takes light 100,000 years to get from one side to another. These galaxies, which are as massive as the Milky Way, look like they had most of their mass crammed into something like 1,000 light years. So, they’re massive, but they’re also super-concentrated. The idea we started developing is that maybe these galaxies are so compact that all the starlight
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Images credit: an artist's concept of the JPSS-2 Satellite for NOAA and NASA by Orbital ATK (top); complete temperature map of the world from NOAA's National Weather Service (bottom).
Observe the Moon By Jane Houston Jones and Jessica Stoller-Conrad
This year’s International Observe the Moon Night is on Oct. 20. Look for as-tronomy clubs and science centers in your area inviting you to view the Moon
at their star parties that evening!
On Oct. 20, the 11-day-old waxing gibbous Moon will rise in the late afternoon and set before dawn. Sunlight will reveal most of the lunar surface and the Moon will be visible all night long. You can observe the Moon’s features whether you’re observing with the unaided eye, through binoculars or through a telescope. Here are a few of the Moon’s features you might spot on the evening of October 20:
Sinus Iridum—Latin for “Bay of Rainbows”—is the little half circle visible on the western side of the Moon near the lunar terminator—the line between light and dark. Another feature, the Jura Mountains, ring the Moon’s western edge. You can see them catch the morning Sun. Just south of the Sinus Iridum you can see a large, flat plain called
the Mare Imbrium. This feature is called a mare—Latin for “sea”—because early astrono-mers mistook it for a sea on Moon’s surface. Because the Moon will be approaching full, the large craters Copernicus and Tycho will also take center stage. Copernicus is 58 miles (93 kilometers) across. Alt-hough its impact crater rays—seen as lines leading out from the crater—will be much more visible at Full Moon, you will still be able to see them on October 20. Tycho, on the oth-er hand, lies in a field of craters near the southern edge of the visible surface of the Moon. At 53 miles (85 kilometers) across, it’s a little smaller than Copernicus. However, its mas-sive ray system spans more than 932 miles (1500 kilome-ters)!
And if you’re very observant on the 20th, you’ll be able to check off all six of the Apollo lunar landing site locations, too!
In addition to the Moon, we’ll be able to observe two meteor showers this month: the Ori-onids and the Southern Tau-rids. Although both will have low rates of meteors, they’ll be visible in the same part of the
sky. The Orionids peak on Oct. 21, but they are active from Oct. 16 to Oct. 30. Start looking at about 10 p.m. and you can continue to look until 5 a.m. With the bright moonlight you may see only five to 10 swift and faint Orionids per hour.
If you see a slow, bright meteor, that’s from the Taurid meteor shower. The Taurids radiate from the nearby constel-lation Taurus, the Bull. Taurids are active from Sept. 10 through Nov. 20, so you may see both a slow Taurid and a fast Orionid piercing your sky this month. You’ll be lucky to see five Taurids per hour on the peak night of Oct. 10. You can also still catch the great lineup of bright planets in October, with Jupiter, Saturn and Mars lining up with the Moon again this month. And early birds can even catch Venus just before dawn!
You can find out more about International Observe the Moon Night at https://moon.nasa.gov/observe.
This image shows some of the features you might see if you closely observe the Moon. The
stars represent the six Apollo landing sites on the Moon. Credit: NASA/GSFC/Arizona
State University (modified by NASA/JPL-Caltech)
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Hubble Goes Wide to Seek Out Far-Flung Galaxies
The universe is a big place. The Hubble Space Telescope's views burrow deep into space and time, but cover an area a fraction the angular size of the full Moon. The challenge is that these "core samples" of the sky may not fully represent the universe at large. This dilemma for cosmologists is called cosmic variance. By expanding the survey area, such uncertainties in the structure of the universe can be reduced.
A new Hubble observing campaign, called Beyond Ultra-deep Frontier Fields And Legacy Observations (BUFFALO), will boldly expand the space telescope's view into regions that are adjacent to huge galaxy clusters previously photographed by NASA's Spitzer and Hubble space telescopes under a program called Frontier Fields. An important motive for the BUFFALO program is the possibility that there may be significantly fewer than predicted extremely distant galaxies found in the Frontier Fields survey. This led astronomers to propose expanding the search area around each Frontier Fields cluster to seek out more distant galaxies, and therefore more accurately determine the numbers of such galaxies. Although the Frontier Fields have already discovered some of the earliest galaxies, these fields are comparatively small and so may not represent the universe at large. This dilemma for cosmologists is called cosmic variance. By expanding the survey area, such uncertainties in the structure of the universe can be reduced. This means conducting a concise census of the first galaxies in as wide of an area as
feasible. The goal is to improve the probability of identifying some of the rare regions of space with a concentration of early galaxies and the far more common regions that had not yet been able to form galaxies so quickly.
Because Frontier Fields observations have already established what the first galaxies look like, the wid-er area of BUFFALO will enable searches for these galaxies several times more efficiently than the orig-inal Frontier Fields. It will also take advantage of observations from other space telescopes, including ultra-deep Spitzer Space Telescope observations that already exist around these clusters.
The BUFFALO program is designed to identify gal-axies in their earliest stages of formation, less than 800 million years after the big bang. These galaxies should help shed light on the processes by which galaxies first assembled. One of BUFFALO’s key goals is to determine how rapidly galaxies formed in this early epoch. This will help astronomers design strategies for using NASA's upcoming James Webb Space Telescope to probe the distant universe with its infrared vision.
Astronomers anticipate that the survey will yield new insights into when the most massive and luminous galaxies formed and how they are linked to dark matter, and how the dynamics of the clusters influ-ence the galaxies in and around them. The survey also will provide a chance to pinpoint images of distant galaxies and supernovas. The six massive clusters were used as "natural telescopes," to look for amplified images of galaxies and supernovas that are so distant and faint that they could not be photographed by Hubble without the boost of light caused by a phenomenon called gravitational lensing. The clusters' large masses, mainly com-posed of dark matter, magnify and distort the light coming from distant background galaxies that other-wise could not be detected. The BUFFALO program is designed to identify galaxies in their earliest stag-es of formation, less than 800 million years after the big bang.
In this view the huge cluster Abell 370, located about 4 billion light-years away, lies in the center of this image. It contains several hundred galaxies. The mosaic of fields flanking the cluster contains myriad background galaxies flung across space and time.
Massive galaxy clusters like Abell 370 are mainly composed of dark matter. Their large masses distort space, turning them into gravitational lenses that magnify and distort the light coming from distant background galaxies. The Frontier Fields program, a previous joint effort from NASA's Great Observatories to study several clusters, allowed for the dis-covery of background galaxies and supernovas that are so distant and faint that they could not have been photographed by Hubble without the aid of this additional gravitational am-plification.
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Astronomers Find First Compelling Evidence for a Moon Outside our Solar System
A pair of Columbia University astronomers using NASA's Hubble Space Telescope and Kepler Space Telescope have assembled compelling evidence for the existence of a moon orbiting a gas-giant planet 8,000 light-years away. In a paper published Oct. 3 in the journal Science Advances, Alex Teachey and David Kipping report that the detec-tion of a candidate exomoon -- that is, moons orbiting planets in other star systems -- is unusual because of its large
size, comparable to the diameter of Neptune. Such gargantuan moons do not exist in our own solar system, where nearly 200 natural satel-lites have been cataloged. "This would be the first case of detecting a moon outside our solar system," said Kipping, an assistant professor of astronomy at Colum-bia. "If confirmed by follow-up Hubble observa-tions, the finding could provide vital clues about the development of planetary systems and may cause experts to revisit theories of how moons form around planets." In looking for exomoons, the researchers ana-lyzed data from 284 Kepler-discovered planets that were in comparatively wide orbits, with periods greater than 30 days, around their host star. The observations measured the momen-tary dimming of starlight as a planet passed in front of its star, called a transit. The researchers
found one instance, in Kepler 1625b, that had intriguing anomalies. "We saw little deviations and wobbles in the light curve that caught our attention," Kipping said. The Kepler results were enough for the team to get 40 hours of time with Hubble to intensively study the planet, obtaining data four times more precise than that of Kepler. The researchers monitored the planet before and during its 19-hour-long transit across the face of the star. After it ended, Hubble detected a second and much smaller de-crease in the star's brightness 3.5 hours later, consistent with "a moon trailing the planet like a dog following its own-er on a leash," Kipping said. "Unfortunately, the scheduled Hubble observations ended before the complete transit of the moon could be measured." In addition to this dip in light, Hubble provided supporting evidence for the moon hypothesis by measuring that the planet began its transit 1.25 hours earlier than predicted. This is consistent with the planet and moon orbiting a com-mon center of gravity (barycenter) that would cause the planet to wobble from its predicted location. "An extraterrestrial civilization watching the Earth and Moon transit the Sun would note similar anomalies in the tim-ing of Earth's transit," Kipping said. The researchers note that in principle this anomaly could be caused by the gravitational pull of a hypothetical sec-ond planet in the system, although Kepler found no evidence for additional planets around the star during its four-year mission. "A companion moon is the simplest and most natural explanation for the second dip in the light curve and the orbit-timing deviation," said lead author Teachey, NSF Graduate Fellow in astronomy at Columbia. "It was a shocking moment to see that light curve, my heart started beating a little faster and I just kept looking at that signature. But we knew our job was to keep a level head testing every conceivable way in which the data could be tricking us until we were left with no other explanation." The moon is estimated to be only 1.5 percent the mass of its companion planet, which itself estimated to be several times the mass of Jupiter. This value is close to the mass-ratio between the Earth and its moon. But in the case of the Earth-Moon system and the Pluto-Charon system -- the largest of the five known natural satellites of the dwarf planet Pluto -- an early collision with a larger body is hypothesized to have blasted off material that later coalesced into a moon. Kepler 1625b and its satellite, however, are gaseous, not rocky, and, therefore, such a collision may not lead to the condensation of a satellite. Exomoons are difficult to find because they are smaller than their com-
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This is an artist's impression of the exoplanet Kepler-1625b, transiting the star, with the candidate exomoon in tow. Credit: Dan Durda
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“One theory is that there could be what is known as a ‘fallback disk’ of material that coalesced around the neutron star after the supernova,” said Posselt. “Such a disk would be composed of matter from the progenitor massive star. Its subsequent interaction with the neutron star could have heated the pulsar and slowed its rotation. If con-firmed as a supernova fallback disk, this result could change our general understanding of neutron star evolution.”
The second possible explanation for the extended infrared emission from this neutron star is a “pulsar wind nebu-la.” “A pulsar wind nebula would require that the neutron star exhibits a pulsar wind,” said Posselt. “A pulsar wind can be produced when particles are accelerated in the electrical field that is produced by the fast rotation of a neu-tron star with a strong magnetic field. As the neutron star travels through the interstellar medium at greater than the speed of sound, a shock can form where the interstellar medium and the pulsar wind interact. The shocked parti-cles would then emit synchrotron radiation, causing the extended infrared signal that we see. Typically, pulsar wind nebulae are seen in X-rays and an infrared-only pulsar wind nebula would be very unusual and exciting.” Using NASA’s upcoming James Webb Space Telescope, astronomers will be able to further explore this newly opened discovery space in the infrared to better understand neutron star evolution.
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panion planet and so their transit signal is weak; they also shift position with each transit because the moon is orbit-ing the planet. In addition, the ideal candidate planets hosting moons are in large orbits, with long and infrequent transit times. In this search, the Neptune-sized moon would have been among the easiest to first detect because of its large size. The host planet and its moon lie within the solar mass star's (Kepler 1625) habitable zone, where moderate temperatures allow for the existence of liquid water on any solid planetary surface. "Both bodies, howev-er, are considered to be gaseous and therefore unsuitable for life as we know it," Kipping said. Future searches will target Jupiter-sized planets that are farther from their star than Earth is from the Sun. There are just a handful of these in the Kepler database. NASA's upcoming James Webb Space Telescope could really "clean-up" in the satel-lite search, Kipping said. "We can expect to see really tiny moons."
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from all the stars in these galaxies jammed into this small space is intense enough by itself to drive the gas out of the galaxies.” Rudnick said the idea is that stars emit light particles that would bump into particles of gas and “give them a little push. The sum of many of these little pushes is enough to push all the gas out of the galaxy at incredible speeds. When you condense an entire Milky Way into a small spot because of a merger of galax-ies, it can cause hundreds of billions of stars to be in a very compact place,” he said. “When that happens, you can put enough light into a small enough space, and that can be enough to push all of the gas out of a galaxy, with no extra energy needed from gas falling into a supermassive black hole.” The NSF grant work will enable further observation and study of this class of self-quenching galaxies. Rudnick said he and his colleagues will be studying the galaxies in as many ways as possible, using telescopes such as NASA’s CHANDRA X-ray Ob-servatory, the Keck Observatories in Hawaii and the Atacama Large Millimeter Array (ALMA) in Chile. “How common is it that these galaxies are shutting themselves off this way?” he asked. “Is the galaxy really able to blow out all its gas completely — or are we seeing really fast, small stream? It’s like you have a teakettle on the stove and it’s hot and a stream of gas is shooting out of the teakettle. You know this gas is shooting out, and we’d like to know if there’s enough gas shooting out that it will empty the teakettle completely.”
Rudnick has just coauthored a paper that used the ALMA telescope to look within a self-quenching galaxy at “the densest, coldest gas — the stuff that’s actually forming the stars.” In that paper, they ask, “What evidence do we have for that gas blowing out?” The KU researcher and his co-authors found the galaxy to be the com-pact remains of a violent merger between two galaxies. This “merger remnant” also hosts huge winds of dense molecular gas but without any trace of an active galactic nucleus. They wanted to determine how the fast the dense gas was gas being driven out of the galaxy. “ALMA uses light with much a longer wavelength than visi-ble light — with a wavelength of a tenth of a millimeter,” Rudnick said.
“It turns out carbon monoxide molecules in this gas give off light you can see with a telescope from Earth. Most of the gas is actually hydrogen, but hydrogen is hard to see from Earth, so we pick a trace gas. It’s a lot like natural gas, you can’t smell it, so they put something in it to make it smell like rotten eggs. Carbon monoxide works like that, in that it tells us where the hard-to-see molecular hydrogen is. We use ALMA to detect carbon monoxide and use that to detect how much total molecular gas. We found this gas, which makes up much of what the galaxy has, is moving from the center of the galaxy at 1,000 kilometers per second. It’s really the stuff that forms stars that’s being blown out.”
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Hubble Uncovers Never Before Seen Features Around a Neutron Star
An unusual infrared light emission from a nearby neutron star detected by NASA’s Hubble Space Telescope, could indicate new features never before seen. One possibility is that there is a dusty disk surrounding the neutron star; another is that there is an energetic wind coming off the object and slamming into gas in interstellar space the neu-tron star is plowing through.
Although neutron stars are generally studied in radio and high-energy emissions, such as X-rays, this study demonstrates that new and interesting information about neutron stars can also be gained by studying them in infrared light, say researchers.
The observation, by a team of researchers at Pennsylvania State University, University Park, Pennsylvania; Sabanci University, Istanbul, Turkey; and the University of Arizona, Tucson, Arizona could help astronomers better understand the evolution of neutron stars — the incredibly dense remnants after a massive star explodes as a supernova. Neutron stars are also called pulsars because their very fast rotation (typically fractions of a second, in this case 11 seconds) causes time-variable emission from light-emitting regions.
“This particular neutron star belongs to a group of seven nearby X-ray pulsars — nicknamed ‘the Magnificent Sev-en’ — that are hotter than they ought to be considering their ages and available energy reservoir provided by the loss of rotation energy,” said Bettina Posselt, associate research professor of astronomy and astrophysics at Pennsylvania State and the lead author of the paper. “We observed an extended area of infrared emissions around this neutron star — named RX J0806.4-4123 — the total size of which translates into about 200 astronomi-cal units (approximately 18 billion miles) at the assumed distance of the pulsar.”
This is the first neutron star in which an extended signal has been seen only in infrared light. The researchers sug-gest two possibilities that could explain the extended infrared signal seen by the Hubble. The first is that there is a disk of material — possibly mostly dust — surrounding the pulsar.
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This illustration shows a neutron star (RX J0806.4-4123) with a disk of warm dust that produces an infrared signa-ture as detected by NASA’s Hubble Space Telescope. The disk wasn’t directly photographed, but one way to ex-plain the data is by hypothesizing a disk structure that could be 18 billion miles across. The disk would be made up of material falling back onto the neutron star after the supernova explosion that created the stellar remnant.
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Making Head or Tail of a Galactic Landscape Astronomers have used data from NASA's Chandra X-ray Observatory to capture a dramatic image of an enormous tail of hot gas stretching for more than a million light years behind a group of galaxies that is falling into the depths of an even-larger cluster of galaxies. Discoveries like this help astronomers learn about the environment and conditions under which the Universe's biggest structures evolve. Galaxy clusters are the largest structures in the Universe held together by gravity. While galaxy clusters can contain hundreds or even thousands of individual galaxies, the lion's share of mass in a galaxy cluster comes from hot gas, which gives off X-rays, and unseen dark matter. How did these cosmic giants get to be so big? This new image shows one way: the capture of galaxies as they are drawn in by the extraordinarily powerful gravity of a galaxy cluster. In the left panel, a wide-field view of the cluster, called Abell 2142, is seen. Abell 2142 contains hundreds of galaxies embedded in multi-million-degree gas detected by Chandra (purple). The center of the galaxy cluster is located in the middle of the purple emission, in the lower part of the image. Only the densest hot gas is shown here, implying that less dense gas farther away from the middle of the cluster is not depicted in the purple emission. In this composite image, the Chandra data have been combined with optical data from the Sloan Digital Sky Survey in red, green, and blue.
A bright X-ray tail located in the upper left of the image is aiming straight for Abell 2142. The right panel contains a closer view of this tail. A galaxy group containing four bright galaxies is near the "head" while the "tail" extends off to the upper left. (Galaxy groups, as defined by astronomers contain a handful to a few dozen galaxies, as opposed to much more populous galaxy clusters.) The direction of the tail and the sharp leading edge of the hot gas around the galaxy group, identified in the labeled version, shows that the group is falling almost di-rectly towards the center of Abell 2142. A close-up
view of the four bright galaxies (named G1, G3, G4 and G5) is shown as an optical and X-ray im-age. The galaxy G2 is a background object, rather than a member of the galaxy group.
As the group of galaxies falls into Abell 2142, some of the hot gas is stripped off, much like leaves from a tree in the fall during a strong gust of wind. As the gas gets stripped off, it forms into a straight and relatively narrow tail that extends for some 800,000 light years. The shape of the tail suggests that magnetic fields draped around it are act-ing like a shield to contain the gas.Beyond about a million light years, the tail flares and becomes irregular. This may mean the turbulence in the galaxy cluster's hot gas is stronger in that area, helping to break down the effect of the magnetic shield. The lower side of the tail flares out more than the upper side. This may be caused by a previ-ous asymmetry in the hot gas in the galaxy group. Such an asymmetry could result from an outburst generated by a supermassive black hole in one of the galaxies in the group, or from mergers between galaxies in the group. Such events could lead to some parts of the galaxy group's gas being stripped more easily than others. The new Chan-dra data also confirm that two of four bright galaxies in the group, G3 and G4, contain rapidly growing, supermas-sive black holes. The two corresponding X-ray sources are closely overlapping in the Chandra image.
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AM 0644-741: Cosmic Collision Forges Galactic One Ring -- in X-rays
Astronomers have used NASA's Chandra X-ray Observatory to discover a ring of black holes or neutron stars in a galaxy 300 million light years from Earth.
This ring, while not wielding power over Mid-dle Earth, may help scientists better under-stand what happens when galaxies smash into one another in catastrophic impacts.
In this new composite image of the galaxy AM 0644-741 (AM 0644 for short), X-rays from Chandra (purple) have been combined with optical data from NASA's Hubble Space Telescope (red, green, and blue). The Chan-dra data reveal the presence of very bright X-ray sources, most likely binary systems powered by either a stellar-mass black hole or neutron star, in a remarkable ring. The results are reported in a new paper led by Anna Wolter from INAF-Osservatorio Astro-nomico di Brera in Milano, Italy. Where did the ring of black holes or neutron stars in AM 0644 come from? Astronomers think that it was created when one galaxy was pulled into another galaxy by the force of gravity. The first galaxy generated ripples in the gas of the second galaxy, AM 0644, located in the lower right. These ripples then produced an expanding ring of gas in AM 0644 that triggered the birth of new stars. The first galaxy is possibly the one located in
the lower left of the image. The most massive of these fledgling stars will lead short lives — in cosmic terms — of millions of years. After that, their nuclear fuel is spent and the stars explode as supernovas leaving behind either black holes with masses typically between about five to twenty times that of the Sun, or neutron stars with a mass approximately equal to that of the Sun. Some of these black holes or neutron stars have close companion stars, and siphon gas from their stellar partner. This gas falls towards the black hole or neutron star, forming a spinning disk like water circling a drain, and be-comes heated by friction. This superheated gas produces large amounts of X-rays that Chandra can detect.
While a ring of black holes or neutron stars is intriguing in itself, there is more to the story of AM 0644. All of the X-ray sources detected in the ring of AM 0644 are bright enough to be classified as ultraluminous X-ray sources (ULXs). This is a class of objects that produce hundreds to thousands of times more X-rays than most "normal" binary systems in which a companion star is in orbit around a neutron star or black hole. Until recently most astron-omers thought that ULXs generally contained stellar-mass black holes, with the possible presence in some cases of intermediate-mass black holes (IMBHs) that contain over a hundred times the mass of the Sun. However, this think-ing was overturned when a few ULXs in other galaxies, including M82 and M51, were found to contain neutron stars. Several other explanations besides IMBHs have been suggested for the intense X-ray emission of ULXs. They in-clude unusually rapid growth of the black hole or neutron star, or geometrical effects arising from the funneling of infalling material along magnetic field lines. The identity of the individual ULXs in AM 0644 is currently unknown. They may be a mixture of black holes and neutron stars, and it is also possible that they are all black holes or all neutron stars. Not all of the X-ray sources in the image are located in the ring of AM 0644. One of the sources is a rapidly growing black hole that's located well behind the galaxy at a distance of 9.1 billion light years from Earth. Another intriguing source detected by Chandra is a growing supermassive black hole located at the center of the galaxy. In the new study, the researchers also used Chandra observations to study six other ring galaxies in addi-tion to AM 0644. A total of 63 sources were detected in the seven galaxies, and 50 of them are ULXs. The authors see a larger average number of ULXs per galaxy in these ring galaxies than in other types of galaxies. Ring galax-ies have stimulated the interest of astronomers because they are ideal testbeds for examining models of how dou-ble stars form, and understanding the origin of ULXs.
Moon Oct 12
Moon Oct 14
The Ecliptic representsthe plane of the solar system. The sun, the moon, and the major planets all lie on or near this imaginary line in the sky.
Relative size of the full moon.
The stars plotted represent those which can be seen from areas suffering
from moderate light pollution. In larger cities, less than
100 stars are visible, while from dark,rural areas well
over ten times that amount
are found.
Navigating the October night sky: Simply start with what you know or with what you can easily find.123
45
Poin
ter St
ars t
o th
e Nor
th St
ar
South
North
West
Capella
Vega
Arcturus
Deneb
Altair
Polaris, the North Star
Cygnus
Cepheus
Cassiopeia
Perseus
Aquila
1
2
3
5a
5b4 B
C
C
C
C
C
A
Astronomical League www.astroleague.org/outreach; duplication is allowed and encouraged for all free distribution.
Relative sizes and distances in the sky can
be deceiving. For instance, 360 "full
moons" can be placed side by side, extending from
horizon to horizon.
Navigating the October Night Sky
Binocular HighlightsA: On the western side of the Keystone glows the Great Hercules Cluster, a ball of 500,000 stars. B: 40% of the way between Altair and Vega, twinkles the "Coathanger," a group of stars outlining a coathanger. C: Sweep along the Milky Way for an astounding number of fuzzy star clusters and nebulae amid many faint glows and dark bays, including the Great Rift. D: The three westernmost stars of Cassiopeia's "W" point south to M31, the Andromeda Galaxy, a "fuzzy" oval. E: Between the "W" of Cassiopeia and Perseus lies the Double Cluster.
+
Mars
Milky Way
The Northern Crown
The Teapot
Numerous star clusters and nebulae
Extend a line north from the two stars at the tip of the Big Dipper's bowl. It passes by Polaris, the North Star.Follow the arc of the Dipper's handle. It intersects Arcturus, the brightest star in the early October evening sky.To the northeast of Arcturus shines another star of the same brightness, Vega. Draw a line from Arcturus to Vega. It first meets "The Northern Crown," then the "Keystone of Hercules." A dark sky is needed to see these two dim stellar configurations.Nearly overhead lie the summer triangle stars of Vega, Altair, and Deneb.High in the east are the four moderately bright stars of the Great Square. Its two southern stars point west to Altair. Its two western stars point south to Fomalhaut.
The Great Square
Sagittarius
CoathangerCluster
Great Rift
Zenith
+M31
D
E
M13
East
Saturn
For observers in the middle northern latitudes, this chart is suitable for early Oct. at 9:00 p.m. and late Oct. at 8:00 p.m.
Pegasus
Fomalhaut
Androm
eda
The SummerTriangle
Double Cluster
10/1
10/31
The Pleiades
The Keystone of Hercules
Mizar/Alcor – nice binocular double star
12
In Memoriam: Dr. George Marvin Brenner, 74, died on May 11, 2018 in Richmond, VA sur-rounded by loving family after an extended illness. He will be remembered for his devotion to family, steadiness and wisdom, and taking on life's challenges with energy and hard work. George was born September 19, 1943, in Ottawa, KS. He grew up on the family farm near Princeton, KS where he was active in 4-H. He enrolled at the University of Kansas and received a B.S. degree in Pharmacy in 1966. George received the first Ph.D. degree awarded in Pharma-cology and Toxicology at K.U. in 1971. George met Mary Ann Robinson while they were attending summer school at KU and doing re-search in the School of Pharmacy. They were married on August 21, 1966. In 1976, the Brenner family moved to Tulsa, OK where George was promoted to Professor at the Center for Health
Sciences of Oklahoma State University. He served as Chair of the Department of Pharmacology and Physiology for fourteen years. During his tenure, George received numerous teaching awards, and authored a pharmacology textbook. The 5th edition, Brenner and Stevens' Pharmacology, was published in 2018. George and Mary Ann returned to Lawrence, KS in 2005 and enjoyed twelve wonderful years there where they were active in several organizations. George was a member of the Lawrence Central Rotary Club. He was active in their community service Projects and served as club treasurer. In 2017, they moved to Richmond, VA to be clos-er to their daughter and grandsons. George and Mary Ann traveled frequently to see children and grandchildren, and enjoyed travel together to Mexico, Central America, and Europe. Enjoying and preserving the natural world was George's life-long passion, and he was proud to support numerous environmental organizations. While in Tulsa, George served as Chair of the Green Country Sierra Club and was a leader in the Inner-city Outings program for disadvantaged youth. He backpacked in Colorado and the Grand Can-yon, and visited numerous state and national parks across the United States. George also enjoyed performing and listening to music throughout his life. He played trumpet in the Princeton school band, University of Kansas band, and local bands in Tulsa and Lawrence. George is survived by his wife Mary Ann, daughter Sharon Brenner and grandsons Ciaran Jones and Braith Jones, of Richmond, VA, son John Brenner and his wife Dannielle and granddaughters Lexi and Sophia Brenner of San Antonio, TX, as well as his brother James Brenner of Los Angeles, CA, sister Brenda Grasmick of Helena, MT, and many extended family members.