Camelopardalis constellation lies in the northern hemisphere. Its name comes from the Latin derivation of the Greek word for ‘giraffe.’ Camelopardalis is the 18th largest constellation in the night sky, occupying an area of 757 square degrees. It is located in the second quadrant of the northern hemisphere (NQ2) and can be seen at latitudes between +90° and -10°. The neighboring constellations are Auriga, Cassiopeia, Cepheus, Draco, Lynx, Perseus, Ursa Major, and Ursa Minor.
[http://www.constellation-guide.com/constellation-list/camelopardalis-constellation/]
The top half of Camelopardalis, shown on Chart III of the Uranographia atlas of Johann Bode (1801). Also included is the now-obsolete constellation of Rangifer, the reindeer.
[http://www.ianridpath.com/startales/camelopardalis.htm]
Camelopardalis was created by Petrus Plancius in 1613 to represent the animal Rebecca rode to marry Isaac in the Bible. One year later, Jakob Bartsch featured it in his atlas. Johannes Hevelius gave it the official name of ‘Camelopardus’ or ‘Camelopardalis’ because he saw the constellation’s many faint stars as the spots of a giraffe.
In Chinese astronomy, the stars of Camelopardalis are located within a group of circumpolar stars called the Purple Forbidden Enclosure.
[http://jedi-counsel.net/a/astronomy/constellation/Camelopardalis/]
Camelopardalis
[http://www.dibonsmith.com/cam_con.htm]
Diagram of H. A. Rey’s method of connecting the stars of the constellation Camelopardalis, in order to show a giraffe.
Beta Camelopardalis is the brightest star in the constellation Camelopardalis. It is a yellow G-type supergiant with an apparent magnitude of +4.03, approximately 870 light years from Earth. It has two close companions: a 7th magnitude A5 star at 84"; and a 12th magnitude star at 15".
[https://en.wikipedia.org/wiki/Beta_Camelopardalis]
These two reflection nebulae are a small part of a large dust cloud in the constellation Camelopardalis. vdB 15 is the blue area to the top and vdB 14 is the sickle-shaped blue nebula down. At a distance of about 3000 light years, magnitude 5 and magnitude 4 supergiants respectively illuminate them.
[https://stargazerslounge.com/topic/260002-vdb-14-vdb15-in-camelopardalis/]
CS Camelopardalis is a binary star in reflection nebulae vdB 14. It forms a group of stars known as the Camelopardalis R1 association, part of the Cam OB1 association. The near-identical supergiant CE Camelopardalis is located half a degree to the south. The primary component, CS Camelopardalis A, is a blue-white B-type supergiant with a mean apparent magnitude of 4.21m. It is classified as an Alpha Cygni type variable star and its brightness varies from magnitude 4.19m to 4.23m. Its companion, CS Camelopardalis B, is a magnitude 8.7m star located 2.9 arcseconds from the primary.
[https://en.wikipedia.org/wiki/CS_Camelopardalis]
Alpha Camelopardalis, with an apparent visual magnitude of 4.3, is the third brightest star in Camelopardalis, the first and second brightest stars being β Camelopardalis and CS Camelopardalis, respectively. It is the farthest constellational star, with a distance of 6000 light-years from Earth.
This star has a stellar classification of O9 Ia, with the ‘Ia’ indicating that it is an O-type luminous supergiant. It is a massive star with 31 times the mass of the Sun and 37 times the Sun’s radius. The effective temperature of the outer envelope is 30,000 K; much hotter than the Sun’s effective temperature of 5,778 K, giving it the characteristic blue hue of an O-type star. It is emitting 620,000 times the luminosity of the Sun and is a weak X-ray emitter.
Alpha Camelopardalis shows multiple patterns of variability. It may be a non-radial pulsating variable star, which is causing changes in the spectrum being emitted by the photosphere. The absorption lines in the optical spectrum show radial velocity variations, although there is significant uncertainty about the period. Estimates range from a period as low as 0.36 days up to 2.93 days. The stellar wind from this star is not smooth and continuous, but instead shows a behavior indicating clumping at both large and small scales. This star is losing mass rapidly through its stellar wind at a rate of approximately 6.3 × 106 solar masses per year, or the equivalent of the mass of the Sun every 160,000 years.
In 1968, this star was classified as a spectroscopic binary, indicating that it has an orbiting stellar companion with a period of 3.68 days and an orbital eccentricity of 0.45. Subsequent studies refined the period to 3.24 days. However, in 2006 it was recognized that the changes in the spectrum were probably the result of changes in the atmosphere or stellar wind, so it is more likely a single star.
In 1961, based on the criteria that the proper motion of this star indicates a space velocity of greater than 30 km/s, Alpha Camelopardalis was suggested as a candidate runaway star that had been ejected from the cluster NGC 1502. This was based upon the kinematic properties of the star and cluster, as well as the location of this star at a high galactic latitude in an area otherwise lacking in stellar associations. Over the course of a million years, this star should have moved only 1.4° across the sky, while it was estimated as being only two million years old.
Runaway stars such as this with a stellar wind that is moving at supersonic velocity through the interstellar medium have their wind confined by a bow shock due to ram pressure. The dust in this bow shock can be detected using an infrared telescope. Just such a bow shock was observed with NASA’s Wide-field Infrared Survey Explorer, or WISE:
[https://en.wikipedia.org/wiki/Alpha_Camelopardalis]
Alpha Camelopardalis- Speed Demon Creates a Shock
Just as some drivers obey the speed limit while others treat every road as if it were the autobahn, some stars move through space faster than others. NASA’s Wide-field Infrared Survey Explorer, or WISE, captured this image of the star Alpha Camelopardalis, or Alpha Cam in astronomer-speak, speeding through the sky like a motorcyclist zipping through rush-hour traffic. The supergiant star Alpha Cam is the bright star in the middle of this image, surrounded on one side by an arc-shaped cloud of dust and gas, colored red in this infrared view.
Such fast-moving stars are called runaway stars. The distance and speed of Alpha Cam is somewhat uncertain. It is probably somewhere between 1,600 and 6,900 light-years away and moving at an astonishing rate of somewhere between 680 and 4,200 kilometers per second (between 1.5 and 9.4 million miles per hour). It turns out that WISE is particularly adept at imaging bow shocks from runaway stars. Previous examples can be seen around zeta Ophiuchi, AE Aurigae, and Menkhib. But Alpha Cam cranks things up into a different gear. To put its speed into perspective, if Alpha Cam were a car driving across the United States at 4,200 kilometers per second, it would take less than one second to travel from San Francisco to New York City!
Astronomers believe runaway stars are set into motion either through the supernova explosion of a companion star or through gravitational interactions with other stars in a cluster. Because Alpha Cam is a supergiant star, it gives off a very strong wind. The speed of the wind is boosted in the forward direction the star is moving in space. When this fast-moving wind slams into the slower-moving interstellar material, a bow shock is created, similar to the wake in front of the bow of a ship in water. The stellar wind compresses the interstellar gas and dust, causing it to heat up and glow in infrared. Alpha Cam’s bow shock cannot be seen in visible light, but WISE’s infrared detectors show us the graceful arc of heated gas and dust around the star.
The red arc of Alpha Cam adds to collection of colorful objects in WISE images taken of the constellation Camelopardalis, or the Giraffe. The gaudily clad giraffe has what looks like a ruby choker above an emerald necklace just to the southeast, as well as an ankle bracelet.
The colors used in this image represent specific wavelengths of infrared light. Stars are seen primarily in blue and cyan (blue-green), because they are emitting light brightly at 3.4 and 4.6 microns. Green represents 12-micron light, primarily emitted by dust. The red of the blow shock represents light emitted at 22 microns.
[http://wise.ssl.berkeley.edu/gallery_alphacam.html]
Gas Shell Around Z Cam
Z Camelopardalis is a cataclysmic variable star in the constellation of Camelopardalis. It has an apparent visual magnitude which varies between 10.0 and 14.5. It is the prototype star for the family of Z Camelopardalis variable stars.
[https://en.wikipedia.org/wiki/Z_Camelopardalis]
Astronomers Spy Monster Star Merger on the Move
The two stars in the MY Cam system (artist’s rendering, above) are so close together that they will end up merging into one supermassive star, astronomers say.
Twin monster stars are merging, astronomers report, in a confirmation of a long-held theory on how supermassive stars are born.
A Spanish astronomy team reports the eclipsing binary star system, known as MY Camelopardalis (MY Cam), in the journal Astronomy & Astrophysics. From Earth, the system’s two gigantic stars appear to eclipse one another almost every day, as they circle on a very tight orbit.
By looking at the high-resolution spectra of the two stars with the powerful 2.2-meter telescope at the Calar Alto Observatory in southern Spain, the researchers were able to determine the physical properties of each of the stars, including their surface temperatures and sizes.
The two hot, blue stars, weighing in at 38 and 32 times the mass of our sun, complete orbits of each other in less than 1.2 days. That is so close that the team concludes they are inevitably destined to merge into a single behemoth star, one that will have an astounding 60 times the mass of the sun.
The authors of the recently published study show that MY Cam is already one of the heftiest binary star systems ever seen. In fact, the two stars are likely close enough that their outer atmospheres are already touching and interacting. They are also rotating around each other at whopping speeds of 621,000 miles (one million kilometers) per hour.
MY Cam was discovered to be a binary system only about a decade ago. Amateur astronomers had been viewing what looked like a single star for years, and had misclassified it as a variable star that fluctuated in brightness. We now know this change in brightness is due to one star rapidly eclipsing the other as they circle around each other.
Astronomers believe that both jumbo stars are no more than two million years old. They probably formed as we see them today.
What will happen next to the stars is a bit of a mystery, but theoretical models suggest that any merger will likely come quickly and quite explosively, releasing copious amounts of energy in the blast.
Astrophysicists believe that the merger of such close binary stars probably best explains how extremely massive stars are born. Astronomers have never witnessed such a merger, explaining their interest in MY Cam.
MY Cam is nestled within a small open star cluster known as Alicante 1, which is located about 13,000 light-years from Earth. It is the brightest member of this sparsely populated stellar nursery filled with hot, young stars only a few million years old.
This sky chart pinpoints the location of MY Cam as seen with the naked eye and with binoculars
You can find MY Cam hiding out in the constellation Camelopardalis, the Giraffe, which is visible throughout the Northern Hemisphere high in the northeastern evening sky (in winter). MY Cam sits at the end of the hind legs of the Giraffe, and its brightness appears to vary between 9.8 and 10.1 magnitude. That makes it just visible with binoculars but a fairly easy target for small backyard telescopes.
[http://news.nationalgeographic.com/news/2014/12/141209-starstruck-monster-star-merger-space-astronomy-science/]
Red giant blows a bubble
A bright star is surrounded by a tenuous shell of gas in this unusual image from the NASA/ESA Hubble Space Telescope. U Camelopardalis, or U Cam for short, is a star nearing the end of its life. As it begins to run low on fuel, it is becoming unstable. Every few thousand years, it coughs out a nearly spherical shell of gas as a layer of helium around its core begins to fuse. The gas ejected in the star’s latest eruption is clearly visible in this picture as a faint bubble of gas surrounding the star.
U Cam is an example of a carbon star. This is a rare type of star whose atmosphere contains more carbon than oxygen. Due to its low surface gravity, typically as much as half of the total mass of a carbon star may be lost by way of powerful stellar winds.
Located in the constellation of Camelopardalis (The Giraffe), near the North Celestial Pole, U Cam itself is actually much smaller than it appears in Hubble’s picture. In fact, the star would easily fit within a single pixel at the centre of the image. Its brightness, however, is enough to overwhelm the capability of Hubble’s Advanced Camera for Surveys making the star look much bigger than it really is.
The shell of gas, which is both much larger and much fainter than its parent star, is visible in intricate detail in Hubble’s portrait. While phenomena that occur at the ends of stars’ lives are often quite irregular and unstable, the shell of gas expelled from U Cam is almost perfectly spherical.
The image was produced with the High Resolution Channel of the Advanced Camera for Surveys.
Distance: 1500 light years.
[https://www.spacetelescope.org/images/potw1227a/]
SGR 0418+5729: A Hidden Population of Exotic Neutron Stars
This graphic shows an exotic object in our galaxy called SGR 0418+5729 (SGR 0418 for short). SGR 0418 is a magnetar, a type of neutron star that has a relatively slow spin rate and generates occasional large blasts of X-rays.
The only plausible source for the energy emitted in these outbursts is the magnetic energy stored in the star. Most magnetars have extremely high magnetic fields on their surface that are ten to a thousand times stronger than for the average neutron star. New data shows that SGR 0418 doesn’t fit that pattern. It has a surface magnetic field similar to that of mainstream neutron stars.
In the image on the left, data from NASA’s Chandra X-ray Observatory shows SGR 0418 as a pink source in the middle. Optical data from the William Herschel telescope in La Palma and infrared data from NASA’s Spitzer Space Telescope are shown in red, green and blue.
On the right is an artist’s impression showing a close-up view of SGR 0418. This illustration highlights the weak surface magnetic field of the magnetar, and the relatively strong, wound-up magnetic field lurking in the hotter interior of the star. The X-ray emission seen with Chandra comes from a small hot spot, not shown in the illustration. At the end of the outburst this spot has a radius of only about 160 meters, compared with a radius for the whole star of about 12 km.
The researchers monitored SGR 0418 for over three years using Chandra, ESA’s XMM-Newton as well as NASA’s Swift and RXTE satellites. They were able to make an accurate estimate of the strength of the external magnetic field by measuring how its rotation speed changes during an X-ray outburst. These outbursts are likely caused by fractures in the crust of the neutron star precipitated by the buildup of stress in the stronger magnetic field lying below the surface.
By modeling the evolution of the cooling of the neutron star and its crust, as well as the gradual decay of its magnetic field, the researchers estimated that SGR 0418 is about 550,000 years old. This makes SGR 0418 older than most other magnetars, and this extended lifetime has probably allowed the surface magnetic field strength to decline over time. Because the crust weakened and the interior magnetic field is relatively strong, outbursts could still occur.
SGR 0418 is located in the Milky Way galaxy at a distance of about 6,500 light years from Earth.
[http://chandra.harvard.edu/photo/2013/sgr0418/]
Heading toward Gliese 445
At the center of this image is the star AC +79 3888, also known as Gliese 445, located 17.6 light-years from Earth. NASA’s Voyager 1 spacecraft, which is on a trajectory out of our solar system, is headed toward an encounter with AC +79 3888. In about 40,000 years, Voyager 1 will be closer to this star than our own sun.
[http://www.nasa.gov/mission_pages/voyager/multimedia/pia17461.html#.V3mUrDUrRWA]
Gliese 445 (Gl 445) is an M-type main sequence star in the constellation of Camelopardalis, close to Polaris, and has an apparent magnitude of 10.8. It is visible from north of the Tropic of Cancer all night long, but not to the naked eye. Because the star is a red dwarf with a mass only a quarter to a third of that of our Sun, scientists question the ability of this system to support life. Gliese 445 is also a known X-ray source.
The Voyager 1 probe will pass within 1.6 light years of Gliese 445 in about 40,000 years. However, by that time the probe will no longer be operational. While the Voyager probe flies through space slowly closing on Gliese 445, the star is rapidly approaching the Sun. At the time the probe passes Gliese 445, the star will be about 1.059 parsecs (3.45 light-years) from the Sun, but with less than half the brightness necessary to be seen with the naked eye.
[https://en.wikipedia.org/wiki/Gliese_445]
HD 104985, also named Tonatiuh, is a helium-fusing yellow giant star located 97 parsecs (317 lys) from the Sun in the constellation of Camelopardalis. An extrasolar planet (designated HD 104985 b, later named Meztli) is believed to orbit the star. Following its discovery in 2003, the planet was designated HD 104985 b. In July 2014 the International Astronomical Union launched a process for giving proper names to certain exoplanets and their host stars. The process involved public nomination and voting for the new names. In December 2015, the IAU announced the winning names were Tonatiuh for this star and Meztli for its planet. The winning names were those submitted by the Sociedad Astronomica Urania of Morelos, Mexico. ‘Tonatiuh’ was the Aztec god of the Sun, while ‘Meztli’ was the Aztec goddess of the Moon.
[https://en.wikipedia.org/wiki/HD_104985]
Kemble’s Cascade and NGC 1502 in Camelopardalis
NGC 1502 is a magnitude 6.9 open cluster about 3,000 light years from Earth. It has about 45 bright members, and features a double star of magnitude 7.0 at its center. NGC 1502 is also associated with Kemble’s Cascade, a simple but beautiful asterism appearing in the sky as a chain of stars 2.5° long that is parallel to the Milky Way and is pointed towards Cassiopeia.
NGC 1501 is a planetary nebula located roughly 1.4° south of NGC 1502:
Hubble View of Bubbly Nebula
This image from Hubble’s Wide Field Planetary Camera 2 showcases NGC 1501, a complex planetary nebula located in the large but faint constellation of Camelopardalis (The Giraffe).
Discovered by William Herschel in 1787, NGC 1501 is a planetary nebula that is just under 5,000 light-years away from us. Astronomers have modeled the three-dimensional structure of the nebula, finding it to be a cloud shaped as an irregular ellipsoid filled with bumpy and bubbly regions. It has a bright central star that can be seen easily in this image, shining brightly from within the nebula’s cloud. This bright pearl embedded within its glowing shell inspired the nebula’s popular nickname: the Oyster Nebula.
While NGC 1501’s central star blasted off its outer shell long ago, it still remains very hot and luminous, although it is quite tricky for observers to spot through modest telescopes. This star has actually been the subject of many studies by astronomers due to one very unusual feature: it seems to be pulsating, varying quite significantly in brightness over a typical timescale of just half an hour. While variable stars are not unusual, it is uncommon to find one at the heart of a planetary nebula.
The colors in this image are arbitrary.
[https://www.nasa.gov/content/goddard/hubble-view-of-bubbly-nebula]
NGC 2403 in Camelopardalis
Magnificent island universe NGC 2403 stands within the boundaries of the long-necked constellation Camelopardalis. Some 10 million light-years distant and about 50,000 light-years across, the spiral galaxy also seems to have more than its fair share of giant star forming HII regions (of interstellar ionized hydrogen), marked by the telltale reddish glow of atomic hydrogen gas. The giant HII regions are energized by clusters of hot, massive stars that explode as bright supernovae at the end of their short and furious lives. A member of the M81 group of galaxies, NGC 2403 closely resembles another galaxy with an abundance of star forming regions that lies within our own local galaxy group, M33 the Triangulum Galaxy. Spiky in appearance, bright stars in this colorful galaxy portrait of NGC 2403 lie in the foreground, within our own Milky Way.
[http://apod.nasa.gov/apod/ap150327.html]
Hidden Galaxy IC 342
Similar in size to large, bright spiral galaxies in our neighborhood, IC 342 is a mere 10 million light-years distant in the long-necked, northern constellation Camelopardalis. A sprawling island universe, IC 342 would otherwise be a prominent galaxy in our night sky, but it is hidden from clear view and only glimpsed through the veil of stars, gas and dust clouds along the plane of our own Milky Way galaxy. Even though IC 342’s light is dimmed by intervening cosmic clouds, this deep telescopic image traces the galaxy's obscuring dust, blue star clusters, and glowing pink star forming regions along spiral arms that wind far from the galaxy's core. IC 342 may have undergone a recent burst of star formation activity and is close enough to have gravitationally influenced the evolution of the local group of galaxies and the Milky Way.
[http://apod.nasa.gov/apod/ap130718.html]
NGC 1569: Starburst in a Dwarf Irregular Galaxy
Grand spiral galaxies often seem to get all the glory, flaunting their young, bright, blue star clusters in beautiful, symmetric spiral arms. But small, irregular galaxies form stars too. In fact, as pictured here, dwarf galaxy NGC 1569 is apparently undergoing a burst of star forming activity, thought to have begun over 25 million years ago. The resulting turbulent environment is fed by supernova explosions as the cosmic detonations spew out material and trigger further star formation. Two massive star clusters - youthful counterparts to globular star clusters in our own spiral Milky Way galaxy - are seen left of center in the gorgeous Hubble Space Telescope image. The above picture spans about 8,000 light-years across NGC 1569. A mere 11 million light-years distant, this relatively close starburst galaxy offers astronomers an excellent opportunity to study stellar populations in rapidly evolving galaxies. NGC 1569 lies in the long-necked constellation Camelopardalis.
[http://apod.nasa.gov/apod/ap081229.html]
Feeling the strain
A galaxy being stretched out of shape has been imaged by the NASA/ESA Hubble Space Telescope. Known as NGC 2146, it has been severely warped and deformed so that an immense dusty arm of glittering material now lies directly in front of the centre of the galaxy, as seen in the image.
NGC 2146 is classified as a barred spiral due to its shape, but the most distinctive feature is the dusty spiral arm that has looped in front of the galaxy’s core as seen from our perspective. The forces required to pull this structure out of its natural shape and twist it up to 45 degrees are colossal. The most likely explanation is that a neighbouring galaxy is gravitationally perturbing it and distorting the orbits of many of NGC 2146’s stars. It is probable that we are currently witnessing the end stages of a process which has been occurring for tens of millions of years.
NCG 2146 is undergoing intense bouts of star formation, to such an extent that it is referred to as a starburst galaxy. This is a common state for barred spirals, but the extra gravitational disruption that NGC 2146 is enduring no doubt exacerbates the situation, compressing hydrogen-rich nebulae and triggering stellar birth.
Measuring about 80 000 light-years from end to end, NGC 2146 is slightly smaller than the Milky Way. It lies approximately 70 million light-years distant in the faint northern constellation of Camelopardalis (The Giraffe). Although it is fairly easy to see with a moderate-sized telescope as a faint elongated blur of light it was not spotted until 1876 when the German astronomer Friedrich Winnecke found it visually using just a 16 cm telescope.
This picture was created from images taken with the Wide Field Channel of Hubble’s Advanced Camera for Surveys. Images through a near-infrared filter (F814W, colored blue and orange/brown) were combined with images taken in a filter that isolates the glow from hydrogen gas (F658N, colored red). An additional green color channel was also created by combining the two to help to create a realistic colour rendition for the final picture from this unusual filter combination. The total exposure times were 120 s and 700 s respectively and the field of view is covers 2.6 x 1.6 arcminutes.
[https://www.spacetelescope.org/images/potw1134a/]
MS 0735.6+7421 is a galaxy cluster located in the constellation Camelopardalis. It is notable as the location of one of the largest central galactic black holes in the known universe, which has also apparently produced the most powerful active galactic nucleus eruption ever discovered since the Big Bang:
[https://en.wikipedia.org/wiki/MS_0735.6%2B7421]
Host Galaxy Cluster to Largest Known Radio Eruption
This is a new composite image of galaxy cluster MS0735.6+7421, located about 2.6 billion light-years away in the constellation Camelopardalis. The three views of the region were taken with NASA’s Hubble Space Telescope in Feb. 2006, NASA’s Chandra X-ray Observatory in Nov. 2003, and NRAO’s Very Large Array in Oct. 2004. The Hubble image shows dozens of galaxies bound together by gravity. In Jan. 2005, astronomers reported that a supermassive black hole, lurking in the central bright galaxy, generated the most powerful outburst seen in the universe. The VLA radio image shows jets of high energy particles (in red) streaming from the black hole. These jets pushed the X-ray emitting hot gas (shown in blue in the Chandra image) aside to create two giant cavities in the gas. The cavities are evidence for the massive eruption. The X-ray and radio images show the enormous appetite of large black holes and the profound impact they have on their surroundings.
[http://hubblesite.org/newscenter/archive/releases/2006/51/]
MACS0647-JD is a candidate, based on a photometric redshift estimate, for the farthest known galaxy from Earth at a redshift of about z = 10.7- 11, equivalent to a light travel distance of 13.3 billion light-years (4 billion parsecs). If the distance estimate is correct, it formed 420 million years after the Big Bang:
[https://en.wikipedia.org/wiki/MACS0647-JD]
NASA Great Observatories Find Candidate for Most Distant Object in the Universe to Date
The newly discovered galaxy, named MACS0647-JD, is very young and only a tiny fraction of the size of our Milky Way. The object is observed 420 million years after the big bang. The inset at left shows a close-up of the young dwarf galaxy. This image is a composite taken with Hubble’s WFC 3 and ACS on Oct. 5 and Nov. 29, 2011.
The farthest galaxy appears as a diminutive blob that is only a tiny fraction of the size of our Milky Way galaxy. But it offers a peek back into a time when the universe was 3 percent of its present age of 13.7 billion years. The newly discovered galaxy, named MACS0647-JD, was observed 420 million years after the big bang, the theorized beginning of the universe. Its light has traveled 13.3 billion years to reach Earth.
This find is the latest discovery from a program that uses natural zoom lenses to reveal distant galaxies in the early universe. The Cluster Lensing And Supernova Survey with Hubble (CLASH), an international group led by Marc Postman of the Space Telescope Science Institute in Baltimore, Md., is using massive galaxy clusters as cosmic telescopes to magnify distant galaxies behind them. This effect is called gravitational lensing.
Along the way, 8 billion years into its journey, light from MACS0647-JD took a detour along multiple paths around the massive galaxy cluster MACS J0647+7015. Without the cluster’s magnification powers, astronomers would not have seen this remote galaxy. Because of gravitational lensing, the CLASH research team was able to observe three magnified images of MACS0647-JD with the Hubble telescope. The cluster’s gravity boosted the light from the faraway galaxy, making the images appear about eight, seven, and two times brighter than they otherwise would that enabled astronomers to detect the galaxy more efficiently and with greater confidence.
“This cluster does what no manmade telescope can do,” said Postman. “Without the magnification, it would require a Herculean effort to observe this galaxy.”
MACS0647-JD is so small it may be in the first steps of forming a larger galaxy. An analysis shows the galaxy is less than 600 light-years wide. Based on observations of somewhat closer galaxies, astronomers estimate that a typical galaxy of a similar age should be about 2,000 light-years wide. For comparison, the Large Magellanic Cloud, a dwarf galaxy companion to the Milky Way, is 14,000 light-years wide. Our Milky Way is 150,000 light-years across.
“This object may be one of many building blocks of a galaxy,” said the study’s lead author, Dan Coe of the Space Telescope Science Institute. “Over the next 13 billion years, it may have dozens, hundreds, or even thousands of merging events with other galaxies and galaxy fragments.”
The galaxy was observed with 17 filters, spanning near-ultraviolet to near-infrared wavelengths, using Hubble’s Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS). Coe, a CLASH team member, discovered the galaxy in February while poring over a catalogue of thousands of gravitationally lensed objects found in Hubble observations of 17 clusters in the CLASH survey. But the galaxy appeared only in the two reddest filters.
“So either MACS0647-JD is a very red object, only shining at red wavelengths, or it is extremely distant and its light has been ‘redshifted’ to these wavelengths, or some combination of the two,” Coe said. “We considered this full range of possibilities.”
The CLASH team identified multiple images of eight galaxies lensed by the galaxy cluster. Their positions allowed the team to produce a map of the cluster’s mass, which is primarily composed of dark matter. Dark matter is an invisible form of matter that makes up the bulk of the universe’s mass. “It’s like a big puzzle,” said Coe. “We have to arrange the mass in the cluster so that it deflects the light of each galaxy to the positions observed.” The team’s analysis revealed that the cluster’s mass distribution produced three lensed images of MACS0647-JD at the positions and relative brightness observed in the Hubble image.
Coe and his collaborators spent months systematically ruling out these other alternative explanations for the object’s identity, including red stars, brown dwarfs, and red (old or dusty) galaxies at intermediate distances from Earth. They concluded that a very distant galaxy was the correct explanation.
Redshift is a consequence of the expansion of space over cosmic time. Astronomers study the distant universe in near-infrared light because the expansion of space stretches ultraviolet and visible light from galaxies into infrared wavelengths. Coe estimates MACS0647-JD has a redshift of 11, the highest yet observed.
Images of the galaxy at longer wavelengths obtained with the Spitzer Space Telescope played a key role in the analysis. If the object were intrinsically red, it would appear bright in the Spitzer images. Instead, the galaxy barely was detected, if at all, indicating its great distance. The research team plans to use Spitzer to obtain deeper observations of the galaxy, which should yield confident detections as well as estimates of the object’s age and dust content.
MACS0647-JD galaxy, however, may be too far away for any current telescope to confirm the distance based on spectroscopy, which spreads out an object’s light into thousands of colors. Nevertheless, Coe is confident the fledgling galaxy is the new distance champion based on its unique colors and the research team’s extensive analysis. “All three of the lensed galaxy images match fairly well and are in positions you would expect for a galaxy at that remote distance when you look at the predictions from our best lens models for this cluster,” Coe said.
The new distance champion is the second remote galaxy uncovered in the CLASH survey, a multi-wavelength census of 25 hefty galaxy clusters with Hubble’s ACS and WFC3. Earlier this year, the CLASH team announced the discovery of a galaxy that existed when the universe was 490 million years old, 70 million years later than the new record-breaking galaxy. So far, the survey has completed observations for 20 of the 25 clusters.
The team hopes to use Hubble to search for more dwarf galaxies at these early epochs. If these infant galaxies are numerous, then they could have provided the energy to burn off the fog of hydrogen that blanketed the universe, a process called re-ionization. Re-ionization ultimately made the universe transparent to light.
[http://www.nasa.gov/mission_pages/hubble/science/distance-record.html]
A Camelopardalid meteor flashes across eastern Cassiopeia (morning of May 24, 2014)
The annual May meteor shower Camelopardalids from comet 209P/LINEAR have a radiant in Camelopardalis.
The space probe Voyager 1 is moving in the direction of this constellation, though it will not be nearing any of the stars in this constellation for many thousands of years, by which time its power source will be long dead.
[https://en.wikipedia.org/wiki/Camelopardalis]
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