A team of International astronomers, led by members of the Instituto de Astrofísica de Canarias, has measured for the first time the mass of an ultra-diffuse galaxy using the Gran Telescopio CANARIAS
Galaxies, in all their forms from spirals to ellipticals from giants to dwarfs have been widely studied over the past Century. To the surprise of the scientific community last year a new type of galaxy was discovered, residing in a galactic megalopolis known as the Coma Cluster, some 300 million light years away from Earth.
This is a region of the Virgo cluster of galaxies containing the ultra-diffuse galaxy VCC 1287. The main image is 500 thousand light years across, uses a negative image for contrast, and was obtained with a 10-centimetre diameter amateur telescope in Switzerland (Antares Observatory). The zoom-in colour-composite image of VCC 1287 is from the 4-metre Canada-France- Hawai'i telescope. The coloured symbols show globular star clusters targeted for orbital speed measurements with the 10-metre Gran Telescopio CANARIAS (GTC).
Even though they are very numerous, these ultradiffuse galaxies have not been noticed until now because they are very fain. Their stars as spread over a very large area, which makes it particularly difficult to distinguish them from the sky background.
"These galaxies are particularly interesting, given that the violent environment in which they are situation would have destroyged them long ago were they not protected by a large amount of dark matter" says Michael Beasley, the first author or the article published in the journal Astrophysical Journal Letters. "To test this fascinating idea was possible after identifying an ultradiffuse galaxy near enough to study in detail."
This galaxy, VCC 1287, is situated in the Virgo Cluster, some 50 million light years away, and it is surrounded by a swarm of globula clusters, which have proved the key to study its dark matter content. " Globular clusters,made up of hundreds of thousands of stars, orbit within the gravitational field of the ultradiffuse galaxy," adds Aaron Romanowsky of San José State University (USA) one of the authors of the article. "The heavier is a galaxy, the more rapidly its globular clusters move, so they can be used as a cosmic balance."
Using the Gran Telescopio CANARIAS (GTC) the team found that these globular clusters move at high velocity, pulled by a surprisingly strong gravitational field. "Even though dark matter is present in other galaxies, this is an exceptional case" concludes Beasley. "For each kilogramme of ordinary material VCC 1287 contains 3 tonnes of dark matter."
So we can say that ultradiffuse galaxies are essentially composed of dark matter, with very few stars". This conclusion gives the scientists another question "How is it possible for galaxies so diffuse and dark to exist?"
Article: "An overmassive dark halo around an ultra-diffuse galaxy in the Virgo cluster", by Michael Beasley (IAC-ULL), Aaron J. Romanowsky (San José State University-University of California Observatories), Vincenzo Pota (INAF, Osservatorio Astronomico di Capodimonte), Ignacio Martín Navarro (IAC-ULL-University of California Observatories), David Martínez Delgado (Universitat Heidelberg), Fabian Neyer ETH Zurich) y Aaron L. Deich (San José State University), 2016, ApJ Letters, 819, L20.
Elena Mora | EurekAlert!
Scientists discover particles similar to Majorana fermions
25.10.2016 | Chinese Academy of Sciences Headquarters
Light-driven atomic rotations excite magnetic waves
24.10.2016 | Max-Planck-Institut für Struktur und Dynamik der Materie
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
25.10.2016 | Earth Sciences
25.10.2016 | Power and Electrical Engineering
25.10.2016 | Process Engineering