Bursting with Starbirth

ESA - Hubble Space Telescope logo.

28 September 2017

Result of a galactic crash

This oddly-shaped galactic spectacle is bursting with brand new stars. The pink fireworks in this image taken with the NASA/ESA Hubble Space Telescope are regions of intense star formation, triggered by a cosmic-scale collision. The huge galaxy in this image, NGC 4490, has a smaller galaxy in its gravitational grip and is feeling the strain.

Compared to the other fundamental forces in the Universe, gravity is fairly weak. Despite this, gravity has an influence over huge distances and is the driving force behind the motions of the most massive objects in the cosmos. The scattered and warped appearance of the galaxy in this image, NGC 4490, is a prime example of the results of gravity’s unrelenting tug.

Over millions of years, the mutual gravitational attraction between NGC 4490 and its smaller neighbour, NGC 4485, has dragged the two galaxies closer. Eventually, they collided in a swirling crush of stars, gas, and dust. In this image, this most intense period is already over and the two galaxies have moved through each other, untangled themselves, and are speeding apart again. But gravity’s pull is relentless; the galaxies are likely to collide again within a few billion years.

Pan across NGC 4490

Together NGC 4490 and NGC 4485 form the system Arp 269, which is featured in the Atlas of Peculiar Galaxies. They are located 24 million light-years from Earth in the constellation of Canes Venatici (The Hunting Dogs). The extreme tidal forces of their interaction have determined the shapes and properties of the two galaxies. Once a barred spiral galaxy, similar to the Milky Way, NGC 4490’s outlying regions have been stretched out, resulting in its nickname of the Cocoon Galaxy. Virtually no trace of its past spiral structure can be seen from our perspective, although its companion galaxy NGC 4485 — not pictured here — still clings on to its spiral arms.

This cosmic collision has created rippling patches of higher density gas and dust within both galaxies. The conditions there are ripe for star formation; the brilliant pink pockets of light seen here are dense clouds of ionised hydrogen, glowing as they are irradiated with ultraviolet light from nearby young, hot stars. This spectacular burst of new activity has led to NGC 4490’s classification as a starburst galaxy.

Star formation is also evident in the thin thread that connects the two galaxies: a bridge of stars created by the ancient crash, stretching over the 24 000 light-years that currently separate the fated pair. But where there is life, there is also death. Several supernovae have also been spotted in NGC 4490 over the past few decades, including SN 1982F and SN 2008ax.

Hubble Space Telescope

More information:

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

Links:

Images of Hubble: http://www.spacetelescope.org/images/archive/category/spacecraft/

HST websites:

http://hubblesite.org/
http://www.nasa.gov/hubble
http://www.spacetelescope.org/

Image, Video, Text, Credits: ESA/Hubble, NASA/Acknowledgements: D. Calzetti (UMass) and the LEGUS Team, J. Maund (University of Sheffield), and R. Chandar (University of Toledo)/Music credit: Astral Electronic.

Best regards, Orbiter.ch

Unexpected surprise: a final image from Rosetta

ESA - Rosetta Mission patch.

28 September 2017

Scientists analysing the final telemetry sent by Rosetta immediately before it shut down on the surface of the comet last year have reconstructed one last image of its touchdown site.

After more than 12 years in space, and two years following Comet 67P/Churyumov–Gerasimenko as they orbited the Sun, Rosetta’s historic mission concluded on 30 September with the spacecraft descending onto the comet in a region hosting several ancient pits.

Reconstructed last image from Rosetta

It returned a wealth of detailed images and scientific data on the comet’s gas, dust and plasma as it drew closer to the surface.

But there was one last surprise in store for the camera team, who managed to reconstruct the final telemetry packets into a sharp image.

“The last complete image transmitted from Rosetta was the final one that we saw arriving back on Earth in one piece moments before the touchdown at Sais,” says Holger Sierks, principal investigator for the OSIRIS camera at the Max Planck Institute for Solar System Research in Göttingen, Germany.

Rosetta’s last images in context

“Later, we found a few telemetry packets on our server and thought, wow, that could be another image.”

During operations, images were split into telemetry packets aboard Rosetta before they were transmitted to Earth. In the case of the last images taken before touchdown, the image data, corresponding to 23 048 bytes per image, were split into six packets.

For the very last image the transmission was interrupted after three full packets were received, with 12 228 bytes received in total, or just over half of a complete image. This was not recognised as an image by the automatic processing software, but the engineers in Göttingen could make sense of these data fragments to reconstruct the image.

Rosetta’s landing site to scale

Owing to the onboard compression software, the data were not sent pixel-by-pixel but rather layer-by-layer, which gives an increasing level of detail with each layer.

The 53% of transmitted data therefore represents an image with an effective compression ratio of 1:38 compared to the anticipated compression ratio of 1:20, meaning some of the finer detail was lost.

That is, it gets a lot blurrier as you zoom in compared with a full-quality image. This can be likened to compressing an image to send via email, versus an uncompressed version that you would print out and hang on your wall.

The camera was not designed to be used below a few hundred metres from the surface but a sharper image could be achieved using the camera in a special configuration: while the camera was designed to be operated with a colour filter in the optical beam, this was removed for the last images. This would have resulted in the images being blurred for the normal imaging scenario above 300 m, but they came into focus at a ‘sweet spot’ of 15 m distance.

Comet from 331 m

Approaching 15 m therefore improved the focus and thus level of detail, as can be seen in the reconstructed image taken from an altitude of 17.9–21.0 m and corresponding to a 1 x 1 m square region on the surface.

In the meantime, the altitude of the previously published last image has been revised to 23.3–26.2 m. The uncertainty arises from the exact method of altitude calculation and the comet shape model used.

The sequence of images progressively reveals more and more detail of the boulder-strewn surface, providing a lasting impression of Rosetta’s touchdown site.

Notes for Editors:

The reconstructed image was presented in an ESA TV transmission earlier this year. Watch it here: http://www.esa.int/spaceinvideos/Videos/2017/05/Rosetta_s_ongoing_legacy

Related links:

Rosetta Mission: http://www.esa.int/Our_Activities/Space_Science/Rosetta

Rosetta at Astrium: http://www.astrium.eads.net/en/programme/rosetta-1go.html

Rosetta at DLR: http://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10394/

Ground-based comet observation campaign: http://www.rosetta-campaign.net/home

End of mission FAQ: http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_s_grand_finale_frequently_asked_questions

Images, Text, Credits: ESA/Markus Bauer/Matt Taylor/Max Planck Institute for Solar System Research/Holger Sierks/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA/ATG medialab.

Best regards, Orbiter.ch

Crew Looks for Neutron Radiation While Prepping for Spacewalks

ISS - Expedition 53 Mission patch.

September 27, 2017

International Space Station (ISS). Image Credits: STS-132/NASA

Sensors are being installed today in the International Space Station to detect neutron radiation. The crew is also setting up a botany study, conducting human research and getting ready for next week’s spacewalk.

Cosmonaut Sergey Ryazanskiy handed over a set of radiation sensors to NASA astronaut Joe Acaba today. Acaba then installed the sensors in the station’s U.S. segment to measure only the neutron radiation levels the orbital lab is exposed to. The data from the Radi-N2 study will help scientists understand the exposure risk to crew members and develop advanced protective measures.

Image above: The six Expedition 53 crew members gather together in the Destiny laboratory module for a group portrait. From left are astronauts Joe Acaba, Paolo Nespoli and Mark Vande Hei, Commander Randy Bresnik and cosmonauts Sergey Ryazanskiy and Alexander Misurkin. Image Credit: NASA.

Acaba also continued installing hardware for the Veggie-3 experiment to get the station ready for a new crop of lettuce and cabbage. Flight Engineer Mark Vande Hei strapped himself into the station’s exercise bike for the VO2max experiment that observes physical exertion during a space mission.

A pair of spacewalkers took a look at the procedures they will use Oct. 5 to replace a latching end effector at the tip of the Canadarm2. Vande Hei will join Commander Randy Bresnik for that spacewalk and a second planned for Oct. 10. Acaba will join Bresnik for a third spacewalk set for Oct. 18.

Related links:

Radi-N2 study: https://www.nasa.gov/mission_pages/station/research/experiments/898.html

Veggie-3 experiment: https://www.nasa.gov/mission_pages/station/research/experiments/1294.html

VO2max experiment: https://www.nasa.gov/mission_pages/station/research/experiments/655.html

Expedition 53: https://www.nasa.gov/mission_pages/station/expeditions/expedition53/index.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Text, Credits: NASA/Mark Garcia.

Greetings, Orbiter.ch

Gravitational waves detected in Europe

Advanced Virgo logo.

27 September 2017

The Virgo detector recorded for the first time the phenomenon caused by the fusion of two black holes.

For the first time, gravitational waves were recorded by the European detector Virgo, which was recently put back into service. The observation was jointly with two US instruments, said Wednesday an international scientific team.

The phenomenon has been observed by European and American instruments

"The gravitational waves propagated in space for 1.8 billion years before being detected by the Advanced LIGO detector located in Louisiana (USA), and 8 thousandths of a second later by the one located in the United States. Washington State, and finally six thousandths of a second afterwards by Advanced Virgo located near Pisa in Italy, "the CNRS said in a statement.

The American Ligo (Laser Interferometer Gravitational-Wave Observatory) instrument, made up of two identical detectors in Louisiana and Washington, had already observed this phenomenon three times predicted by Albert Einstein's theory of general relativity in 1915. The very first direct detection, announced on February 11, 2016, was a historic event after 40 years of effort.

But it is "the first detection" for Advanced Virgo, which has been restarted on August 1 after several years of improvements and a few months of tests, explains the National Center for Scientific Research (CNRS). Its arrival in the device allows a much better localization in the sky of the sources of gravitational waves.

Merging two black holes

The waves result from slight perturbations of the space-time frame under the effect of the displacement of a massive object, much like a weight deforms a net. These new waves, detected on August 14, 2017 at 12:30, were produced by the fusion of two black holes, about 1.8 billion light years from Earth.

Virgo Detector

The two monsters, which had masses equal to 25 and 31 times that of the Sun, merged into a single black hole of 53 solar masses, the equivalent of 3 solar masses being converted into energy in the form of gravitational waves.

Weekly Detections

Advanced Virgo is an instrument mainly financed by the CNRS in France and the Istituto Nazionale di Fisica Nucleare (INFN) in Italy. It brings together 250 physicists, engineers and technicians from 20 European laboratories. The international team announced this detection on the sidelines of the G7-science meeting in Turin. Their work will be published in the Physical Review Letters.

Advanced Virgo interferometer, detecting gravitational waves from space

"With the next observations scheduled for the fall of 2018, we can expect such detections every week or even more often," said David Shoemaker, Massachusetts Institute of Technology (MIT) astrophysicist and spokesperson for the Ligo collaboration .

Advanced Virgo - Listening to the cosmic whisper: http://public.virgo-gw.eu/language/en/

Images, Text, Credits: ATS/EGO-Virgo/Orbiter.ch Aerospace/Roland Berga.

Best regards, Orbiter.ch

LHC rocks the seesaw model

CERN - European Organization for Nuclear Research logo.

27 Sep 2017

For most of us, seesaws are the stuff of childhood memories. For theoretical physicists, they could explain one of the biggest mysteries in the field: why are neutrinos so incredibly light?

Experiments at CERN’s Large Hadron Collider have now put the unlikely sounding “seesaw model” through one of its most stringent tests.

Image above: Members of the CMS collaboration removing the preshower from ECAL detector in the CMS cavern. (Image: M Brice/CERN).

Discovered 60 years ago, the neutrino was long thought to weigh nothing at all. But experiments in the late 1990s showed that neutrinos change type as they travel, implying that they have a small but non-zero mass. The mystery is why their masses are so small and yet not zero, as assumed by the Standard Model of particle physics. Most other elementary particles acquire their masses by interacting with Higgs bosons: the stronger the interaction the heavier the particle. But many physicists think it a stretch – “unnatural” even – that the Higgs boson interacts so feebly with the neutrino as to leave it at least a million times lighter than the already waif-like electron.

The seesaw model, dreamed up in the 1980s, is an abstract ratio that connects normal neutrinos to an unseen breed of super-heavy particles with weird properties: the neutrinos we know on one end are pivoted up by heavier particles on the other end of the “seesaw”. Were these mathematical gymnastics shown to be responsible for the neutrino’s tiny mass, it would lead physicists to a rich landscape of new particles and phenomena beyond the Standard Model, perhaps even a unified theory of the fundamental forces.

Researchers on the CMS experiment have been searching for signs of the neutrino’s weightier partners among billions of proton-proton collisions produced by the LHC at an energy of 13 TeV. Specifically, they tested a version of the seesaw mechanism (called Type-III) that involves a triplet of two heavy charged particles and an additional neutral particle, which would reveal themselves in the CMS detector via their decays into more familiar objects such as Higgs bosons and electrons. Studies at the LHC have also probed the original Type-I seesaw mechanism, which requires a heavy “sterile” neutrino that does not interact at all with known matter.Such particles are the quarry of several dedicated neutrino experiments worldwide.

Large Hadron Collider (LHC)

Building on previous search results obtained by CMS and its sister experiment ATLAS at lower collision energies, CMS reports no sign of heavy charged particles associated with the seesaw model and has ruled out their existence below a mass of 840 GeV. According to the team, these are the strongest constraints to date on the mass of Type-III seesaw particles. “We have now looked at all 27 relevant decay channels in a single multimodal analysis,” explains CMS member Sunil Somalwar from Rutgers University in the US. “With the seesaw, the higher you set the masses of the new particles the smaller the neutrino mass – which is good. We are now getting into seesaw exclusions at the LHC.”

CMS and ATLAS will subject the seesaw, and many other models of physics beyond the Standard Model, to further scrutiny as the LHC continues to amass data at a record-breaking energy of 13 TeV. 

The CMS result is described in a preprint (http://arxiv.org/abs/1708.07962) and has been submitted to the journal Physical Review Letters.

Note:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

Related links:

Large Hadron Collider (LHC): http://home.cern/topics/large-hadron-collider

CMS experiment: https://home.cern/about/experiments/cms

ATLAS experiment: https://home.cern/about/experiments/atlas

Higgs bosons: https://home.cern/topics/higgs-boson

The Standard Model: http://home.cern/about/physics/standard-model

For more information about European Organization for Nuclear Research (CERN), Visit: http://home.cern/

Image (mentioned), Animation, Text, Credits: CERN/Matthew Chalmers.

Best regards, Orbiter.ch

The Strange Structures of the Saturn Nebula

ESO - European Southern Observatory logo.

27 September 2017

MUSE image of the Saturn Nebula

The spectacular planetary nebula NGC 7009, or the Saturn Nebula, emerges from the darkness like a series of oddly-shaped bubbles, lit up in glorious pinks and blues. This colourful image was captured by the powerful MUSE instrument on ESO’s Very Large Telescope (VLT), as part of a study which mapped the dust inside a planetary nebula for the first time. The map — which reveals a wealth of intricate structures in the dust, including shells, a halo and a curious wave-like feature — will help astronomers understand how planetary nebulae develop their strange shapes and symmetries.

Three-dimensional MUSE view of the Saturn Nebula

The Saturn Nebula is located approximately 5000 light years away in the constellation of Aquarius (The Water Bearer). Its name derives from its odd shape, which resembles everyone’s favourite ringed planet seen edge-on.

But in fact, planetary nebulae have nothing to do with planets. The Saturn Nebula was originally a low-mass star, which expanded into a red giant at the end of its life and began to shed its outer layers. This material was blown out by strong stellar winds and energised by ultraviolet radiation from the hot stellar core left behind, creating a circumstellar nebula of dust and brightly-coloured hot gas. At the heart of the Saturn Nebula lies the doomed star, visible in this image, which is in the process of becoming a white dwarf [1].

Annotated image showing features in the Saturn Nebula

In order to better understand how planetary nebulae are moulded into such odd shapes, an international team of astronomers led by Jeremy Walsh from ESO used the Multi Unit Spectroscopic Explorer (MUSE) to peer inside the dusty veils of the Saturn Nebula. MUSE is an instrument installed on one of the four Unit Telescopes of the Very Large Telescope at ESO’s Paranal Observatory in Chile. It is so powerful because it doesn’t just create an image, but also gathers information about the spectrum — or range of colours — of the light from the object at each point in the image.

The Saturn Nebula in the constellation of Aquarius

The team used MUSE to produce the first detailed optical maps of the gas and dust distributed throughout a planetary nebula [2]. The resulting image of the Saturn Nebula reveals many intricate structures, including an elliptical inner shell, an outer shell, and a halo. It also shows two previously imaged streams extending from either end of the nebula’s long axis, ending in bright ansae (Latin for “handles”).

The sky around the Saturn Nebula

Intriguingly, the team also found a wave-like feature in the dust, which is not yet fully understood. Dust is distributed throughout the nebula, but there is a significant drop in the amount of dust at the rim of the inner shell, where it seems that it is being destroyed. There are several potential mechanisms for this destruction. The inner shell is essentially an expanding shock wave, so it may be smashing into the dust grains and obliterating them, or producing an extra heating effect that evaporates the dust.

Looking at the Saturn Nebula in 3D

Mapping the gas and dust structures within planetary nebulae will aid in understanding their role in the lives and deaths of low mass stars, and it will also help astronomers understand how planetary nebulae acquire their strange and complex shapes.

But MUSE’s capabilities extend far beyond planetary nebulae. This sensitive instrument can also study the formation of stars and galaxies in the early Universe, as well as map the dark matter distribution in galaxy clusters in the nearby Universe. MUSE has also created the first 3D map of the Pillars of Creation in the Eagle Nebula (eso1518) and imaged a spectacular cosmic crash in a nearby galaxy (eso1437).
http://www.eso.org/public/news/eso1518/
http://www.eso.org/public/news/eso1437/

Zooming in on the Saturn Nebula

Notes:

[1] Planetary nebulae are generally short-lived; the Saturn Nebula will last only a few tens of  thousands of years before expanding and cooling to such an extent that it becomes invisible to us. The central star will then fade as it becomes a hot white dwarf.

[2] The NASA/ESA Hubble Space Telescope has previously provided a spectacular image of the Saturn Nebula — but, unlike MUSE, it cannot reveal the spectrum at each point over the whole nebula.

More information:

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.

Links:

ESOcast 129 Light: The Strange Structures of the Saturn Nebula: http://www.eso.org/public/videos/eso1731a/

Photos of the VLT: http://www.eso.org/public/images/archive/category/paranal/

Photos of MUSE: http://www.eso.org/public/images/archive/search/?adv=&subject_name=MUSE

Press release on first light of MUSE: http://www.eso.org/public/news/eso1407/

Multi Unit Spectroscopic Explorer (MUSE): http://www.eso.org/public/teles-instr/paranal-observatory/vlt/vlt-instr/muse/

Very Large Telescope (VLT): http://www.eso.org/public/teles-instr/paranal/

Images, Videos, Text, Credits: ESO/Richard Hook/Jeremy Walsh/IAU and Sky & Telescope/Digitized Sky Survey 2. Acknowledgement: Davide De Martin/L.Calçada/N. Risinger (skysurvey.org). Music: Astral Electronic.

Best regards, Orbiter.ch

Station Readied for Crops, Crew Runs Biomedical Studies

ISS - Expedition 53 Mission patch.

September 26, 2017

International Space Station (ISS). Image Credit: NASA

The International Space Station is once again providing a platform to test the growth of cabbage and lettuce for future human consumption in space. Aside from today’s botany set up, the Expedition 53 crew also explored how living in space affects the human physiology.

NASA astronaut Joe Acaba began setting up hardware for the Veggie-3 experiment Tuesday morning to grow a variety of lettuce and cabbage. Scientists are studying how plants grow in space to learn how to sustain future crews as NASA plans longer missions farther out in space.

Image above: NASA astronaut Mark Vande Hei jogs on a treadmill inside the space station. Image Credit: NASA.

Acaba also joined European Space Agency astronaut Paolo Nespoli collecting blood and urine samples for a pair of biomedical experiments. The long-running Biochemical Profile and Repository studies are documenting the various changes the human body experiences during a long-term space mission.

Commander Randy Bresnik continued gathering spacewalk equipment with Flight Engineer Mark Vande Hei ahead of an Oct. 5 spacewalk. The pair also checked out their emergency jet packs and sized their spacesuits. This will be the first of three spacewalks in October to replace a latching end effector on the tip of the Canadarm2 and replace a pair of external cameras.

Related links:

Veggie-3: https://www.nasa.gov/mission_pages/station/research/experiments/1294.html

Biochemical Profile: https://www.nasa.gov/mission_pages/station/research/experiments/1008.html

Repository: https://www.nasa.gov/mission_pages/station/research/experiments/981.html

Expedition 53: https://www.nasa.gov/mission_pages/station/expeditions/expedition53/index.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Text, Credits: NASA/Mark Garcia.

Best regards, Orbiter.ch