Dark energy camera captures galaxies in lopsided tug of war, a prelude to merger
Haley’s Coronet and dwarf galaxy companion feel each other’s gravitational forces as they begin to coalesce
IMAGE: THE SPIRAL GALAXY NGC 1532, ALSO KNOWN AS HALEY’S CORONET, IS CAUGHT IN A LOPSIDED TUG OF WAR WITH ITS SMALLER NEIGHBOR, THE DWARF GALAXY NGC 1531. THE IMAGE — TAKEN BY THE US DEPARTMENT OF ENERGY’S (DOE) DARK ENERGY CAMERA MOUNTED ON THE NATIONAL SCIENCE FOUNDATION’S (NSF) VÍCTOR M. BLANCO 4-METER TELESCOPE AT CERRO TOLOLO INTER-AMERICAN OBSERVATORY IN CHILE, A PROGRAM OF NSF’S NOIRLAB — CAPTURES THE MUTUAL GRAVITATIONAL INFLUENCES OF A MASSIVE- AND DWARF-GALAXY MERGER. view more
CREDIT: CTIO/NOIRLAB/DOE/NSF/AURA ROBERTO COLOMBARI, M. ZAMANI & D. DE MARTIN (NSF’S NOIRLAB)
Galaxies grow and evolve over billions of years by absorbing nearby companions and merging with other galaxies. The early stages of this galactic growth process are showcased in a new image taken with the US Department of Energy’s (DOE) Dark Energy Camera (DECam) mounted on the National Science Foundation’s (NSF) Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab.
The massive barred spiral galaxy NGC 1532, also known as Haley’s Coronet, is located about 55 million light-years away in the direction of the southern constellation Eridanus (the river). Its sweeping spiral arms are seen edge-on from Earth, with the nearer arm dipping downward and the receding arm lurching upward as it tugs upon its smaller, dwarf companion galaxy NGC 1531. These gravitationally bound galaxies will eventually become one, as NGC 1532 completely consumes its smaller companion.
Despite its small stature, however, the dwarf galaxy has also been exerting a noticeable gravitational influence on its larger companion, distorting one of its spiral arms, which can be seen rising above the galactic plane. Additionally, plumes of gas and dust can be seen between the two galaxies, like a bridge of stellar matter held in place by the competing tidal forces. This interaction has also triggered bursts of star formation within both galaxies.
This lopsided cosmic tug of war is a snapshot of how large galaxies grow and evolve by devouring smaller galaxies, absorbing their stars and star-forming material. A similar process has happened in the Milky Way, possibly six times in the past, leaving vast streams of stars and other signs in the halo of the Milky Way.
The process of absorbing a smaller companion galaxy is starkly different from the cataclysmic merger of two spiral galaxies of comparable size. In the latter case, two massive galaxies collide to form an entirely distinct galaxy with its own shape and characteristics. This type of galactic merger will happen to the Milky Way when it merges with the Andromeda Galaxy four billion years from now.
DECam, with its unparalleled wide-field imaging capabilities, gives astronomers highly detailed views of these large-scale galactic interactions. It also has the remarkable sensitivity, with the help of the 4-meter Blanco telescope, needed to detect faint objects in our Solar System and to trace the influence of dark matter on galaxies across the visible Universe. Currently, DECam is used for programs covering a wide range of science.
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NSF’s NOIRLab (National Optical-Infrared Astronomy Research Laboratory), the US center for ground-based optical-infrared astronomy, operates the international Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), Kitt Peak National Observatory (KPNO), Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and Vera C. Rubin Observatory (in cooperation with DOE’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona. The astronomical community is honored to have the opportunity to conduct astronomical research on Iolkam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence that these sites have to the Tohono O'odham Nation, to the Native Hawaiian community, and to the local communities in Chile, respectively.
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New image reveals secrets of planet birth
IMAGE: AT THE CENTRE OF THIS IMAGE IS THE YOUNG STAR V960 MON, LOCATED OVER 5000 LIGHT-YEARS AWAY IN THE CONSTELLATION MONOCEROS. DUSTY MATERIAL WITH POTENTIAL TO FORM PLANETS SURROUNDS THE STAR. OBSERVATIONS OBTAINED USING THE SPECTRO-POLARIMETRIC HIGH-CONTRAST EXOPLANET RESEARCH (SPHERE - HTTPS://WWW.ESO.ORG/PUBLIC/TELES-INSTR/PARANAL-OBSERVATORY/VLT/VLT-INSTR/SPHERE/) INSTRUMENT ON ESO’S VLT (HTTPS://WWW.ESO.ORG/PUBLIC/TELES-INSTR/PARANAL-OBSERVATORY/VLT/), REPRESENTED IN YELLOW IN THIS IMAGE, SHOW THAT THE DUSTY MATERIAL ORBITING THE YOUNG STAR IS ASSEMBLING TOGETHER IN A SERIES OF INTRICATE SPIRAL ARMS EXTENDING TO DISTANCES GREATER THAN THE ENTIRE SOLAR SYSTEM. MEANWHILE, THE BLUE REGIONS REPRESENT DATA OBTAINED WITH THE ATACAMA LARGE MILLIMETER/SUBMILLIMETER ARRAY (ALMA - HTTPS://WWW.ESO.ORG/PUBLIC/TELES-INSTR/ALMA/), IN WHICH ESO IS A PARTNER. THE ALMA DATA PEERS DEEPER INTO THE STRUCTURE OF THE SPIRAL ARMS, REVEALING LARGE DUSTY CLUMPS THAT COULD CONTRACT AND COLLAPSE TO FORM GIANT PLANETS ROUGHLY THE SIZE OF JUPITER VIA A PROCESS KNOWN AS “GRAVITATIONAL INSTABILITY”. view more
CREDIT: ESO/ALMA (ESO/NAOJ/NRAO)/WEBER ET AL.
A spectacular new image released today by the European Southern Observatory gives us clues about how planets as massive as Jupiter could form. Using ESO’s Very Large Telescope (VLT) and the Atacama Large Millimeter/submillimeter Array (ALMA), researchers have detected large dusty clumps, close to a young star, that could collapse to create giant planets.
“This discovery is truly captivating as it marks the very first detection of clumps around a young star that have the potential to give rise to giant planets,” says Alice Zurlo, a researcher at the Universidad Diego Portales, Chile, involved in the observations.
The work is based on a mesmerising picture obtained with the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument on ESO’s VLT that features fascinating detail of the material around the star V960 Mon. This young star is located over 5000 light-years away in the constellation Monoceros and attracted astronomers’ attention when it suddenly increased its brightness more than twenty times in 2014. SPHERE observations taken shortly after the onset of this brightness ‘outburst’ revealed that the material orbiting V960 Mon is assembling together in a series of intricate spiral arms extending over distances bigger than the entire Solar System.
This finding then motivated astronomers to analyse archive observations of the same system made with ALMA, in which ESO is a partner. The VLT observations probe the surface of the dusty material around the star, while ALMA can peer deeper into its structure. “With ALMA, it became apparent that the spiral arms are undergoing fragmentation, resulting in the formation of clumps with masses akin to those of planets,” says Zurlo.
Astronomers believe that giant planets form either by ‘core accretion’, when dust grains come together, or by ‘gravitational instability’, when large fragments of the material around a star contract and collapse. While researchers have previously found evidence for the first of these scenarios, support for the latter has been scant.
“No one had ever seen a real observation of gravitational instability happening at planetary scales — until now,” says Philipp Weber, a researcher at the University of Santiago, Chile, who led the study published today in The Astrophysical Journal Letters.
“Our group has been searching for signs of how planets form for over ten years, and we couldn't be more thrilled about this incredible discovery,” says team-member Sebastián Pérez from the University of Santiago, Chile.
ESO instruments will help astronomers unveil more details of this captivating planetary system in the making, and ESO’s Extremely Large Telescope (ELT) will play a key role. Currently under construction in Chile’s Atacama Desert, the ELT will be able to observe the system in greater detail than ever before, collecting crucial information about it. “The ELT will enable the exploration of the chemical complexity surrounding these clumps, helping us find out more about the composition of the material from which potential planets are forming,” concludes Weber.
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The team behind this work comprises young researchers from diverse Chilean universities and institutes, under the Millennium Nucleus on Young Exoplanets and their Moons (YEMS) research centre, funded by the Chilean National Agency for Research and Development (ANID) and its Millennium Science Initiative Program. The two facilities used, ALMA and VLT, are located in Chile’s Atacama Desert.
This research is presented in a paper to appear in The Astrophysical Journal Letters (doi: 10.3847/2041-8213/ace186).
The team is composed of P. Weber (Departamento de Física, Universidad de Santiago de Chile, Chile [USACH]; Millennium Nucleus on Young Exoplanets and their Moons, Chile [YEMS]; Center for Interdisciplinary Research in Astrophysics and Space Exploration, Universidad de Santiago de Chile, Chile [CIRAS]), S. Pérez (USACH; YEMS; CIRAS), A. Zurlo (YEMS; Núcleo de Astronomía, Universidad Diego Portales Chile [UDP]; Escuela de Ingeniería Industrial, Universidad Diego Portales, Chile), J. Miley (Joint ALMA Observatory, Chile; National Astronomical Observatory of Japan, Japan), A. Hales (National Radio Astronomy Observatory, USA), L. Cieza (YEMS; UDP), D. Principe (MIT Kavli Institute for Astrophysics and Space Research, USA), M. Cárcamo (YEMS; CIRAS; USACH, Faculty of Engineering, Computer Engineering Department, Chile), A. Garufi (INAF, Osservatorio Astrofisico di Arcetri, Italy), Á. Kóspál (Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Eötvös Loránd Research Network (ELKH), Hungary; CSFK, MTA Centre of Excellence, Hungary; ELTE Eötvös Loránd University, Institute of Physics, Hungary; Max Planck Institute for Astronomy, Germany), M. Takami (Institute of Astronomy and Astrophysics, Academia Sinica, Taiwan, ROC), J. Kastner (School of Physics & Astronomy, Rochester Institute of Technology, USA), Z. Zhu (Department of Physics and Astronomy, University of Nevada, USA; Nevada Center for Astrophysics, University of Nevada, USA), and J. Williams (Institute for Astronomy, University of Hawai‘i at Manoa, USA).
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science and Technology Council (NSTC) in Taiwan and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration for astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 16 Member States (Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom), along with the host state of Chile and with Australia as a Strategic Partner. ESO’s headquarters and its visitor centre and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvellous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its Very Large Telescope Interferometer, as well as survey telescopes such as VISTA. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. Together with international partners, ESO operates ALMA on Chajnantor, a facility that observes the skies in the millimetre and submillimetre range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.
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