Thursday, 10 March 2011

Extremely Young and Incredibly Old

here's my new story about a newly discovered cluster of galaxies, which is located in the young Universe but it is, surprisingly, already pretty old... enjoy :-)

An old galaxy cluster discovered in the young Universe

Astronomers working with data from several observatories, including ESA's XMM-Newton, have discovered the most distant, mature galaxy cluster yet. The cluster is seen as it was when the Universe was only about a quarter of its current age. In contrast to other structures observed in the young Universe, this object is already in its prime, as is evident from its diffuse X-ray emission and evolved population of galaxies. This shows that fully-grown galaxy clusters were already in place this early in cosmic history. More...

Image Credits: ESA/ESO/Subaru/R.Gobat et al.

Wednesday, 16 February 2011

Dark stuff that matters

here's a new story, maybe a teeny bit longer than usual, about the dark 'nests' where the most frenzied galaxies in cosmic history are born...

Herschel quantifies the dark matter threshold for starburst galaxies

How much dark matter is needed to trigger a starburst in the cosmic cribs where galaxies are born? A new study, based on data from ESA's Herschel Space Observatory, has revealed that dark matter halos with a mass larger than 300 billion times the Sun's are particularly efficient at igniting massive starbursts, as they house the most active star-forming galaxies in the Universe. Astronomers have discovered this key threshold by measuring small fluctuations in the Cosmic Infrared Background, the integrated diffuse emission produced by the dust from every galaxy that ever existed. These fluctuations trace the distribution of otherwise mostly unresolved star-forming galaxies and of the dark matter halos that enshroud them. More...

Image credits: The Virgo Consortium/Alexandre Amblard/ESA

Wednesday, 19 January 2011

When a candle gets 'crabby'

Here's a new story about what is standard and what isn't — in astronomy. Incidentally, setting and adjusting to new and old standards is a topic which I recently find more and more interesting when applied to a number of other contexts as well...

The Crab Nebula: standard candle no more?

Teaming up with other telescopes monitoring the Crab Nebula, ESA's INTEGRAL observatory has made a significant contribution to demonstrating that this source, previously believed to be a standard candle, might not be so reliable, after all. The small, but measurable dimming of what was until now considered to be one of the brightest and, most importantly, the steadiest source in the high-energy sky calls for a re-examination of how X-ray and gamma-ray observations are calibrated. More...

Image credits: X-ray: NASA/CXC/SAO/F. Seward; Optical: NASA/ESA/ASU/J. Hester & A. Loll; Infrared: NASA/JPL-Caltech/Univ. Minn./R. Gehrz

Lots of cool stuff

after a long break I'm back with no less than 5 new articles about what can arguably be described as my favourite spacecraft, Planck!! the stories cover a bunch of really cool results that have been achieved from its early data and presented at a conference in Paris last week, spanning a wide range of astronomical objects that will suit everyone's palate — from tiny dust grains in our Galaxy all the way to the huge galaxy clusters and the distribution of galaxies on the largest scales. enjoy :)

Planck's first science results and the release of an extensive compact source catalogue
The Planck Collaboration presents the first science results to emerge from the mission, covering compact and diffuse foreground emission sources, at a conference held from 10 to 14 January 2011 in Paris, France. These results are accompanied by the release of the first Planck product to be publicly distributed: the Early Release Compact Source Catalogue, a highly robust compilation of compact sources detected in each of the telescope's nine channels. Eagerly awaited by the scientific community, the catalogue contents span a wide variety of astronomical sources, and also includes a sample of galaxy clusters detected through the Sunyaev-Zel'dovich effect and a list of cold molecular cloud cores distributed throughout the Milky Way. More...

Planck's successful hunt probes galaxy clusters on very broad mass range
The first all-sky survey of galaxy clusters detected via the Sunyaev-Zel'dovich effect is amongst the highlights presented by the Planck Collaboration at a conference held from 10 to 14 January 2011 in Paris, France. The survey, which has benefited from a fruitful collaboration with ESA's XMM-Newton observatory, probes a wide range of cluster masses and other properties, which is unprecedented for a Sunyaev-Zel'dovich sample. Along with the first results enabled by the survey, the Early Sunyaev-Zel'dovich Cluster sample is being publicly released, providing the community with a robust data set for further studies and follow-up observations of galaxy clusters. More...

Planck traces the coldest objects in the nearby Universe
With its power to detect cosmic material at unprecedentedly low temperatures, Planck has completed the first unbiased, all-sky survey of compact cold and dusty objects in the Milky Way and, at the same time, the first all-sky survey of cool dust in other galaxies. These extensive data sets allow astronomers to shed new light on the earliest phases of star formation. The public release of the Planck Early Cold Core Catalogue will offer the community a large number of new, cold galactic targets to be studied with other telescopes, including ESA's Herschel Space Observatory. More...

Planck sees new, mysterious components in Milky Way and Magellanic Clouds
Thanks to its broad spectral coverage and very high sensitivity, Planck is peering deep into the interstellar medium of the Milky Way and discovering new components and physical mechanisms taking place therein. The results emerging from Planck's first all-sky survey include strong evidence for the presence of extremely rapidly spinning dust grains, an excess emission explained in terms of a previously poorly quantified 'dark gas' and the characterisation of an excess emission arising from the interstellar medium that permeates the Small Magellanic Cloud, a nearby galaxy orbiting our own Milky Way. More...

Planck sees traces of early structure formation in the cosmic infrared background
While targeting the Cosmic Microwave Background, Planck has also captured another important diffuse radiation, the Cosmic Infrared Background, which consists of the light emitted by all galaxies since their formation. This signal, detected by Planck at submillimetre wavelengths, exhibits a high degree of structure and enables astronomers to investigate the still unclear link between star-forming galaxies and the underlying distribution of dark matter, up to the earliest phases of the formation of cosmic structure. More...

Image credits: ESA and the Planck Collaboration

Friday, 3 December 2010

Just like archaeologists

here's a new article about astronomical measurements of radioactive elements in some stars that remind us of the way archaeologists date their samples. apparently, a highly appreciated comparison!! enjoy :-)

INTEGRAL helps unravel the tumultuous recent history of the solar neighbourhood

Just like archaeologists, who rely on radioactive carbon to date the organic remains from past epochs, astronomers have exploited the radioactive decay of an isotope of aluminium to estimate the age of stars in the nearby Scorpius-Centaurus association, the closest group of young and massive stars to the Sun. The new observations, performed in gamma rays by ESA's INTEGRAL observatory, provide evidence for recent ejections of matter from massive stars that took place only a few million years ago in our cosmic neighbourhood. More...

Image credits: ESA

Friday, 19 November 2010

Hot gas fountains and the galactic spa

here's a new article that came out today about new data confirming a mechanism where hot gas bursts out of the Milky Way's disc and into the galactic halo, giving rise to so-called galactic fountains:

New evidence for supernova-driven galactic fountains in the Milky Way

Observing the X-ray-bright gas in the halo of the Milky Way, ESA's XMM-Newton has gathered new data which favour a process involving fountains of hot gas in our Galaxy. Such a scenario, with the gas flowing from the galactic disc into the halo where it then condenses into cooler clouds and subsequently falls back to the disc, confirms the importance of supernova explosions in forging the evolution of the interstellar medium and of the entire Galaxy. More...

Image credits: ESA

Thursday, 4 November 2010

lenses in the sky – without diamonds

and finally a new story about cosmology and a good old friend of yours truly, i.e. gravitational lensing... yay!

New method reveals gravitationally lensed galaxies in Herschel-ATLAS first survey

Astronomers using early data from one of the largest projects to be undertaken with the ESA Herschel Space Observatory have demonstrated that virtually all bright sub-millimetre galaxies in the distant Universe are subject to gravitational lensing, which amplifies their flux thus easing their detection and characterisation. Analysis of less than three per cent of the entire Herschel-ATLAS survey, which probes the distant and hidden Universe, yielded a first sample of five lensed galaxies and paves the way for the compilation, in the near future, of a rich catalogue of distant, star-forming and dust-obscured galaxies. More...

Image credits: ESA/NASA/JPL-Caltech/Keck/SMA