29
Nov 10

Direct observational evidence for a large transient galaxy population in groups at 0.85 < z < 1

Source: arXiv

A team leaded by Michael Balogh of the University of Waterloo, Ontario Canada, has presented the results of a survey of galaxy groups at 0.85 < z < 1, as an extension of the Group Environment and Evolution Collaboration (GEEC).  The first results based on Gemini GMOS-S nod-and-shuffle spectroscopy of seven galaxy groups selected from spectroscopically confirmed, extended XMM detections in COSMOS.  Like lower-redshift groups, these systems are dominated by red galaxies, at all stellar masses Mstar > 1010.1M. Few group galaxies inhabit the “blue cloud” that dominates the surrounding field. The authors found there exists a large and possibly distinct population of galaxies with intermediate colours. The “green valley” that exists at low redshift is instead well-populated in these groups, containing about 30 per cent of the galaxies. These do not appear to be exceptionally dusty galaxies.

Furthermore, their HST morphologies appear to be intermediate between those of red-sequence and blue-cloud galaxies of the same stellar mass. Unlike red-sequence galaxies, most of the green galaxies have a disk component, but one that is smaller and less structured than disks found in the blue cloud. We postulate that these are a transient population, migrating from the blue cloud to the red sequence, with a star formation rate that declines with an exponential timescale 0.6Gyr < z < 2Gyr. Such galaxies may not be exclusive to the group environment, as we find examples also amongst the non-members. However, their prominence among the group galaxy population, and the marked lack of blue, star-forming galaxies, provides evidence that the group environment either directly reduces star formation in member galaxies, or at least prevents its rejuvenation during the normal cycle of galaxy evolution.

This work has been accepted to publication by the Monthy Notices of the Royal Astronomical Society (MNRAS). (read the article at arXiv)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
28
Nov 10

Events before the Big Bang?

Source: arXiv

Roger Penrose, a well known cosmologist, posted an article on the arXiv website were he as co-author of V.G.Gurzadyan says that analysis of this cosmic microwave background showed echoes of previous Big Bang-like events. These events seem to appear as "rings" around galaxy clusters in which the variation in the background is unusually low.

The ideas within it support a theory developed by Professor Penrose - knighted in 1994 for his services to science - that upends the widely-held "inflationary theory". That theory holds that, at a certain moment, the Universe was shaped by an unthinkably large and fast expansion from a single point.

Much of high-energy physics research aims to try to elucidate how the laws of nature evolved during the fleeting first instants of the Universe's being.

The article claims that this aeon is just one of a succession of such things, where the remote future of the previous aeons somehow becomes the Big Bang of our aeon. This "conformal cyclic cosmology" (CCC) that Professor Penrose advocates allows that the laws of nature may evolve with time, but precludes the need to institute a theoretical beginning to the Universe a theory that has been also defended by other cosmologists in several different perspectives. (read the text at arXiv).

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
27
Nov 10

Hylas-1 in orbit brings Europe broadband from space

Source: ESA PR27-2010


Ariane 5 launcher lifted off from Europe’s Spaceport in French Guiana on its
mission to place two telecommunications satellites, Hylas-1 and Intelsat 17.
Image credits: ESA/CNES/ARIANESPACE - Optique Video CSG - S. Martin, 2010

A flawless launch has delivered Hylas-1, ESA's first public-private partnership in a full satellite system, into space. The satellite was released today into its transfer orbit after a textbook launch by an Ariane 5 vehicle from Europe's Spaceport in French Guiana.

Owned and operated by Avanti Communications plc of the UK, and with its key payload constituents developed by EADS Astrium in the framework of ESA's Advanced Research in Telecommunication Systems (ARTES) programme, through funding essentially from the UK Space Agency, the Hylas-1 communication satellite will demonstrate advanced high-speed technologies and provide innovative broadband services across Europe.

The 53rd Ariane 5 (V198) lifted off from Kourou, French Guiana, at 15:39 local time (18:39 GMT, 19:39 CET) and released its two payloads, Hylas-1 and Intelsat-17, into their planned transfer orbits.

ESA has devoted years to developing satellite broadband technologies through its Advanced Research in Telecommunication Systems (ARTES) programme. Now several of these innovations are being put to work on Hylas-1.

ESA's involvement focuses on the mission's most inventive element - its highly adaptable payload. The satellite's flexible technology means that it can modify its data throughput across the European regions it serves, keeping pace with market demand.

"ESA's cooperation with Avanti Communications on Hylas-1 is a prime example of a public-private partnership, a creative fast-track for demonstrating and reaping the benefits of satellite high technology as part of an operational mission," commented Magali Vaissiere, ESA Director of Telecommunications and Integrated Applications

This is a new way of working that ESA will pursue in telecoms. Within the next 24 months, two similar initiatives in partnership with satellite operators Inmarsat and Hispasat will foster the development of state-of-the-art technologies to serve the new needs of the worldwide market and Europe's citizens. (read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
27
Nov 10

Were wandering globular clusters the first dwarf galaxies in the universe?

Source: arXiv

In the last decade the advent of new types of dwarf stellar systems became a reality.

The new dwarf stellar systems include ultra-compact dwarfs, ultra-faint dwarf spheroidals, and exotic globular clusters, breaking the old simple paradigm for dwarf galaxies and globular clusters. These objects become more intriguing, and understanding of these new findings becomes more challenging. Recently we discovered a new type of large scale structure in the Virgo cluster of galaxies: it is composed of globular clusters. Globular clusters in Virgo are found wandering between galaxies (intraclus- ter globular clusters) as well as in galaxies.


The Virgo Galaxy Cluster. Source:DSS.

These intracluster globular clusters fill a significant fraction in the area of the Virgo cluster and they are dominated by blue globular clusters. These intracluster globular clusters may be closely related with the first dwarf galaxies in the universe. (read the full pdf article from arXiv)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
27
Nov 10

Galaxies pin down dark energy

Source: Physics World
Hubble Space Telescope image of a pair of spiral galaxies with swirling arms.
The galactic system is located in the constellation of Draco, about 350 million light-years away.
Image credit: NASA, ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration
and A Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University)

A new way of measuring the geometry of the universe confirms that dark energy dominates the cosmos and bolsters the idea that this unusual form of energy is described by Einstein's cosmological constant. The technique, developed by physicists in France, involves a relatively easy measurement of the orientation of distant pairs of galaxies.

Over the past decade or so, several kinds of observation, such as measurements of the distances of remote supernovae, have provided strong evidence that the expansion of the universe is accelerating. Cosmologists believe that this expansion is being driven by what is known as dark energy – a substance with negative pressure that opposes the pull of gravity. Unfortunately, however, they have little idea of what dark energy actually is, having been unable to measure its properties well enough to distinguish between rival hypotheses.(read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
27
Nov 10

Space Ministers emphasise priority to deliver Galileo and GMES

Source: ESA PR26-2010


Credit&Copyright: ESA/A. Le Floc'h.

Ministers in charge of space activities representing the Member States of the European Space Agency and the European Union met in Brussels today for the Seventh Space Council. Today's Council was jointly chaired by Sabine Laruelle, the Belgian Minister of Small and Medium Enterprises, the Self-employed, Agriculture and Science Policy, on behalf of the EU Competitive-ness Council, and Giuseppe Pizza, Italian State Secretary in the Ministry of Education, University and Research, on behalf of the ESA Council at Ministerial Level. Antonio Tajani, Vice-President of the European Commission and Commissioner for Enterprise & Industry, and Jean-Jacques Dordain, ESA Director General, also took part. The Space Council unanimously endorsed a resolution that called for the necessary actions to deliver a space strategy that would enable economic growth, respond to public policy objectives and develop the vocations of science and technology in Europe. Ministers emphasised that the flagship programmes Galileo and GMES (Global Monitoring for Environment and Security) remain the priorities for the EU in space and identified the key decisions to be taken in these areas over the coming months. In the areas of Global Climate Change and Security, the ministers asked the European Commission and the Director General of ESA to collaborate with the Member States and other relevant actors in Europe to identify how to fill gaps in existing space capabilities. Ministers also recognised the need to move towards establishing a Space Situational Awareness capability for the protection of Europe's space assets. They stressed the need for Europe to voice a single European position in international discussions on space exploration. Following on from the 16 September conference 'Space for the African Citizen' and taking account of the expected inclusion of space in the communication for the EU-Africa Summit, to be held in Libya on 29 and 30 November, the Space Council called for expanded partnerships with the African Union, the Regional Economic Groupings and African nations to build capacities for acquiring and exploiting space systems. Aware that the EU-ESA Framework Agreement, under which the Space Council was established, has been extended until May 2012, ministers of the EU and ESA invited the European Commission and the Director General of ESA respectively to conduct an evaluation by May 2011 of the experience gained under that agreement. ESA Director General Jean-Jacques Dordain emphasised the progress that had been achieved in space missions since the previous Space Council meeting in May 2009, adding: "The entry into force of the Treaty on the Functioning of the European Union, with a specific space competence, is good news for space, good news for Europe and good news for ESA. It allows us not to do the same thing differently but to do more, together."

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
27
Nov 10

Cassini Finds an Oxygen–Carbon Dioxide Atmosphere at Saturn’s Icy Moon Rhea

Source: Science Express

The flyby measurements of the Cassini spacecraft at Saturn’s moon Rhea reveal a tenuous oxygen–carbon dioxide atmosphere. The atmosphere appears to be sustained by chemical decomposition of the surface water ice under irradiation from Saturn’s magnetospheric plasma. This in situ detection of an oxidizing atmosphere is consistent with remote observations of other icy bodies such as Jupiter’s moons Europa and Ganymede, and suggestive of a reservoir of radiolytic O2 locked within Rhea’s ice. The presence of CO2 suggests radiolysis reactions between surface oxidants and organics, or sputtering and/or outgassing of CO2 endogenic to Rhea’s ice. Observations of outflowing positive and negative ions give evidence for pickup ionization as a major atmospheric loss mechanism. (see source-requires subscription)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
27
Nov 10

A new model from Very Low Mass Stars to Brown Dwarfs

Source: arXiv

Since the discovery of brown dwarfs in 1994, and the discovery of dust cloud formation in the latest Very Low Mass Stars (VLMs) and Brown Dwarfs (BDs) in 1996, the most important challenge in modeling their atmospheres as become the understanding of cloud formation and advective mixing.

Many cloud models have been constructed to address this problem in brown dwarfs over the past decade, but none treated the mixing properties of the atmosphere, and the resulting diffusion mechanism realistically enough to reproduce the properties of the spectral transition from M through L and T spectral types without changing cloud parameters. One of the most important challenge in modeling the atmospheres and spectral properties of VLMs and brown dwarfs is the formation of dust clouds and its associated greenhouse effects making the infrared colors of late M and early L dwarfs extremely red compared to colors of low mass stars. The cloud composition, according to equilibrium chemistry, is going from zirconium oxide (ZrO2 ), to refractory ceramics (perovskite and corundum; CaTiO3 , Al2O3 ), to silicates (forsterite; Mg2SiO4 ), to salts (CsCl, RbCl, NaCl), and finally to ices (H2O, NH3 , NH4 SH).

An international team leaded by France Allard, co-authored by Homeier and Freytag has now proposed a 2D a new model atmosphere grid, named BT-Settl, computed using an updated version of the atmosphere code Phoenix and compared it to the AMES-Cond/Dusty models, on several parameters and found that the model is quite god on covering the whole range of VLMs and brown dwarfs and beyond: 1000,000 K < T eff < 400 K; -0.5 < logg <5.5; and +0.5 < [M/H] < -4.0, including various values of the alpha element enhancement. (read full article)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
26
Nov 10

Observing campaign on BM Ori and the Trapezium region

Source: AAVSO Alert Notice 427

The American Association of Variable Stars Observers (AAVSO) requests ground-based observations of the Trapezium region of the Orion Nebula (M42), along with surrounding regions in Orion, in conjunction with upcoming observations with the MOST Satellite.  All AAVSO observers are encouraged to participate in this project, and we are requesting observations for a number of different targets from both instrumental and visual observers.


The Orion Nebula(M42). The white region slightly left and up of the centre of the image is the Trapezium region.

This observing program headed by Dr. Matthew Templeton is exploring low-amplitude variability in bright stars of the Trapezium using the Canadian satellite MOST (Microvariability and Oscillations of Stars). This is an exploratory proposal to search for low-amplitude variability in these young stars due to any number of potential causes: pulsations, magnetic activity and rotation, or accretion processes are all possible. MOST will be capable of measuring the light curves of many stars in the Trapezium with precision better than 1 mmag.

The observations will be conducted at some point during the December 2010 - January 2011 time-frame, and will span approximately one month.  We are requesting observations before, during, and after the observing window, and several of the targets are worthwhile long-term monitoring objects as well. Observers from multiple longitudes are especially encouraged.  Since this is an equatorial source, both northern and southern hemisphere observers are encouraged to participate. (read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
26
Nov 10

Happy Birthday EAAE News

It was on November 26th, 2009 that the EAAE News published its first post.

One year later and nearly 300 posts we are proud to be read by several hundred subscribers by email every day.

Thank you for reading us. This is the best support we have.

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
25
Nov 10

Pulsating Star Mystery Solved

Source: ESO Science Release eso1046


Artist’s impression of the remarkable double star OGLE-LMC-CEP0227.
Image credit: ESO/L. Calçada

By discovering the first double star where a pulsating Cepheid variable and another star pass in front of one another, an international team of astronomers has solved a decades-old mystery. The rare alignment of the orbits of the two stars in the double star system has allowed a measurement of the Cepheid mass with unprecedented accuracy. Up to now astronomers had two incompatible theoretical predictions of Cepheid masses. The new result shows that the prediction from stellar pulsation theory is spot on, while the prediction from stellar evolution theory is at odds with the new observations. (read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
25
Nov 10

Jupiter's belt is coming back

Source: NASA/JPL

New NASA images support findings that one of Jupiter's stripes that "disappeared" last spring is now showing signs of a comeback. These new observations will help scientists better understand the interaction between Jupiter's winds and cloud chemistry.


This is a composite of three color images taken on Nov. 18, 2010, by the Gemini North telescope in Hawaii.
The composite image shows a belt that had previously vanished in Jupiter's atmosphere is now reappearing.
Image credit: NASA/JPL/UH/NIRI/Gemini/UC Berkeley

Earlier this year, amateur astronomers noticed that a longstanding dark-brown stripe, known as the South Equatorial Belt, just south of Jupiter's equator, had turned white. In early November, amateur astronomer Christopher Go of Cebu City, Philippines, saw an unusually bright spot in the white area that was once the dark stripe. This phenomenon piqued the interest of scientists at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and elsewhere.

After follow-up observations in Hawaii with NASA's Infrared Telescope Facility, the W.M. Keck Observatory and the Gemini Observatory telescope, scientists now believe the vanished dark stripe is making a comeback. (read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
24
Nov 10

The Sun Steals Comets from Other Stars

Source: NASA Science News


Contrast-enhanced image obtained during Deep Impact's Nov. 4th flyby of Comet Hartley 2.
Could this comet rock-star have been stolen from another stellar system? No one knows.
Image credit: NASA/Deep Impact.

Some of the comets in our Solar System probably came from other stars, according to new research by NASA-supported scientists. Studying these 'alien' comets, they say, could reveal new information about stellar systems far, far away. (read ore)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
23
Nov 10

ESA's GlobCorine delivers map from space

Source: ESA

Meeting the environmental needs of an ever-expanding Europe requires consistent and regularly updated information on its land cover and use. As part of ESA's GlobCorine project, a pan-European land cover and use map for 2009 is now available online.(read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
21
Nov 10

15th EAAE-IAU Summer School in Heidelberg, Germany

Between the 18th and the 20th of November, 2010, German SOFIA Institute (DSI) and the House of Astronomy (HdA)organized, in association with the EAAE and IAU, the 15th EAAE-IAU Summer School in Heidelberg, Germany. The language of this Summer School was German. The Summer School chairpersons wer  Cecilia Scorza and Olaf Fischer, both of them members of the EAAE and and the IAU.

A plan of the Haus der Astronomie were the course occured.

The Summer School was designed for school teachers interested in astronomy, in particular in infrared astronomy and spectroscopy, under the theme "Spectroscopy for the school".

General Lectures and Workshops were presented by EAAE, IAU members and teachers with long experience.  Workshops provided very practical and didactic material that teachers  caneasily use and implement in school practice.

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
20
Nov 10

Planet from another galaxy discovered

Source: ESO Science Release eso1045


Artist’s impression of HIP 13044 b, an exoplanet orbiting a star that entered our galaxy.
Image credit: ESO/L. Calçada

An exoplanet orbiting a star that entered our Milky Way from another galaxy has been detected by a European team of astronomers using the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile. The Jupiter-like planet is particularly unusual, as it is orbiting a star nearing the end of its life and could be about to be engulfed by it, giving tantalising clues about the fate of our own planetary system in the distant future.(read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
20
Nov 10

Cometary Snowstorm Engulfs Hartley 2

Source: NASA Science News


Comet Snowstorm. Image credit: NASA/Deep Impact

NASA has just issued a travel advisory for spacecraft: Watch out for Comet Hartley 2, it is experiencing a significant winter snowstorm.

Deep Impact photographed the unexpected tempest when it flew past the comet's nucleus on Nov. 4th at a distance of only 700 km (435 miles). At first, researchers only noticed the comet's hyperactive jets. The icy nucleus is studded with them, flamboyantly spewing carbon dioxide from dozens of sites. A closer look revealed an even greater marvel, however. The space around the comet's core is glistening with chunks of ice and snow, some of them possibly as large as a basketball. (read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
18
Nov 10

15th EAAE-IAU Astronomy Summer School in Germany

15th EAAE-IAU Astronomy Summer School
November 18rd - 20th 2010
Heidelberg, Germany

Organisers:
German SOFIA Institute (DSI)
House of astronomy (HdA)
European Association for Astronomy Education (EAAE)
International Astronomical Union (IAU)

EAAE launches the the 15th Summer School between November 18th  and November 20th. This SS will be held in Heidelberg in Germany.

The Summer School is for school teachers interested in astronomy, in particular in infrared astronomy and spectroscopy. The preliminary theme of this Summer School is spectroscopy for the school. General Lectures and Workshops will be presented by EAAE, IAU members and teachers with long experience. The objective of WS is to offer teachers very practical and didactic material which can be implemented at school. Observation sessions can be held during the Summer School depending on the weather. The goal is to introduce the participants into the basics of spectroscopy. The course will offer participants special visit to the Max-Planck-Institute of astronomy and the building of the House of astronomy - Heidelberg. The language of the Summer School is German.

Contact details:
Summer School chair: Cecilia Scorza (member of the EAAE and IAU) and
Olaf Fischer (Member EAAE and IAU)
e-mail: scorza@mpia.de

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
17
Nov 10

The Best Meteor Shower Of The Year

There are several major meteor showers to enjoy every year at various times, with some more active than others. The 2010 Leonid meteor shower peaks the evening of Wednesday, Nov. 17.

If you're viewing in dark conditions, the best viewing time will be after midnight, in the hours just before dawn. But don't expect too much. While the annual shower has been spectacular in the past, this year's 85% full moon will obstruct viewing for most backyard astronomers. At most, expect to see approximately 15 meteors per hour.

Whether you're watching from a downtown area or the dark countryside, here are some tips to help you enjoy these celestial shows of shooting stars. Those streaks of light are really caused by tiny specks of comet-stuff hitting Earth's atmosphere at very high speed and disintegrating in flashes of light.

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
17
Nov 10

Youngest-Ever Nearby Black Hole Discovered

Credit: NASA Science


This composite image shows a supernova within the galaxy M100 that may contain the youngest known black hole in our cosmic neighborhood. In this image, Chandra’s X-rays are colored gold, while optical data from ESO’s Very Large Telescope are shown in red, green, and blue, and infrared data from Spitzer are red. The location of the supernova, known as SN 1979C, is labeled. Image credits: X-ray: NASA/CXC/SAO/D.Patnaude et al, Optical: ESO/VLT, Infrared: NASA/JPL/Caltech

Astronomers using NASA's Chandra X-ray Observatory have found evidence of the youngest black hole known to exist in our cosmic neighborhood. The 30-year-old object provides a unique opportunity to watch a black hole develop from infancy. (read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon