(Press-News.org) The NASA/ESA Hubble Space Telescope has imaged a set of enigmatic quasar ghosts -- ethereal green objects which mark the graves of these objects that flickered to life and then faded. The eight unusual looped structures orbit their host galaxies and glow in a bright and eerie goblin-green hue. They offer new insights into the turbulent pasts of these galaxies.
The ethereal wisps in these images were illuminated, perhaps briefly, by a blast of radiation from a quasar -- a very luminous and compact region that surrounds a supermassive black hole at the centre of a galaxy. Galactic material falls inwards towards the central black hole, growing hotter and hotter, forming a bright and brilliant quasar with powerful jets of particles and energy beaming above and below the disc of infalling matter.
In each of these eight images a quasar beam has caused once-invisible filaments in deep space to glow through a process called photoionisation. Oxygen, helium, nitrogen, sulphur and neon in the filaments absorb light from the quasar and slowly re-emit it over many thousands of years. Their unmistakable emerald hue is caused by ionised oxygen, which glows green.
These ghostly structures are so far from the galaxy's heart that it would have taken light from the quasar tens of thousands of years to reach them and light them up. So, although the quasars themselves have turned off, the green clouds will continue to glow for much longer before they too fade.
Not only are the green filaments far from the centres of their host galaxies, they are also immense in size, spanning tens of thousands of light-years. They are thought to be long tails of gas formed during a violent past merger (between galaxies) -- this event would have caused strong gravitational forces that would rip apart the galactic participants.
Despite their turbulent past, these ghostly filaments are now leisurely orbiting within or around their new host galaxies. These Hubble images show bright, braided and knotted streams of gas, in some cases connected to twisted lanes of dark dust.
Galactic mergers do not just alter the forms of the previously serene galaxies involved; they also trigger extreme cosmic phenomena. Such a merger could also have caused the birth of a quasar, by pouring material into the galaxies' supermassive black holes.
The first object of this type was found in 2007 by Dutch schoolteacher Hanny van Arkel (heic1102). She discovered the ghostly structure in the online Galaxy Zoo project, a project enlisting the help of the public to classify more than a million galaxies catalogued in the Sloan Digital Sky Survey (SDSS). The bizarre feature was dubbed Hanny's Voorwerp (Dutch for Hanny's object).
These objects were found in a spin-off of the Galaxy Zoo project, in which about 200 volunteers examined over 16 000 galaxy images in the SDSS to identify the best candidates for clouds similar to Hanny's Voorwerp. A team of researchers analysed these and found a total of twenty galaxies that had gas ionised by quasars. Their results appear in a paper in the Astronomical Journal.
Those featured here are (from left to right on top row) the Teacup (more formally known as 2MASX J14302986+1339117), NGC 5972, 2MASX J15100402+0740370 and UGC 7342, and (from left to right on bottom row) NGC 5252, Mrk 1498, UGC 11185 and 2MASX J22014163+1151237.
INFORMATION:
Notes
Notes for editors
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
More information
Image credit: NASA, ESA, Galaxy Zoo team & W. Keel (University of Alabama, USA)
Links
Images of Hubble - http://www.spacetelescope.org/images/archive/category/spacecraft/
Link to hubblesite release - http://hubblesite.org/newscenter/archive/releases/2015/13
Related research paper - http://arxiv.org/abs/1408.5159
Contacts
William Keel
University of Alabama
Tuscaloosa, Alabama, USA
Tel: +1-205-348-1641
Email: wkeel@ua.edu
Ray Villard
Space Telescope Science Institute
Baltimore, Maryland, USA
Tel: +1-410-338-4514
Email: villard@stsci.edu
Georgia Bladon
ESA/Hubble, Public Information Officer
Garching bei München, Germany
Tel: +44 7816291261
Email: gbladon@partner.eso.org
A new statistical analysis suggests that, in the short term, the Mexican government's war against drugs increased the average murder rate in regions subjected to military-style interventions.
The study--"Did the Military Interventions in the Mexican Drug War Increase Violence?"--was conducted by Valeria Espinosa, a quantitative analyst at Google and a 2014 doctoral graduate of Harvard University's statistics department, and Donald B. Rubin, Harvard University John L. Loeb Professor of Statistics.
The paper is published on the website of The American Statistician, a ...
Philadelphia, PA, April 2, 2015 - With each new amyloid-targeting treatment for Alzheimer's disease that has been developed, there has been a corresponding concern. For example, antibodies targeting amyloid-β peptide (Aβ) produce inflammation in the brain in some patients. Gamma secretase inhibitors tend to produce adverse effects by interacting with Notch, an important pathway for cellular signaling.
Beta secretase 1 (BACE1) inhibitors are a new and promising target for Alzheimer's disease. Inhibiting BACE1 will limit the production of Aβ which, in turn, ...
SEATTLE - As the global population pushes past 7 billion and more people reach old age, the number of deaths from cardiovascular diseases is on the rise. Cardiovascular diseases, the leading cause of premature death in the world, include heart attacks, strokes, and other circulatory diseases.
At the same time, efforts to prevent and treat cardiovascular diseases appear to be working as the rise in deaths is slower than the overall growth of the population.
Globally, the number of deaths due to cardiovascular diseases increased by 41% between 1990 and 2013, climbing ...
Scientists from Nanyang Technological University (NTU Singapore) and Sweden's Karolinska Institutet, one of Europe's largest and most prestigious medical universities, have discovered that an existing chemotherapy drug used to treat leukaemia could prevent and control the growth of colorectal tumours.
Colorectal cancer commonly referred to as colon cancer is one of the three most common cancers worldwide and the most common in Singapore. Almost 95 per cent of colorectal cancers are from malignant tumours.
The research team found that Imatinib, an enzyme blocker widely ...
Reporting under policy instruments to inform on the trends in biodiversity requires information from a range of different elements of biodiversity, from genetically viable populations to the structure of ecosystems. A new research looks into the Essential Biodiversity Variables as an analytic framework to identify ways in which gaps between biodiversity data and policy reporting needs could be bridged. The study was published in the Journal of Applied Ecology.
The Essential Biodiversity Variables (EBVs, Pereira et al. 2013) which were previously developed by ecology experts ...
The findings, which have been published in the American Journal of Clinical Nutrition, are in line with previous studies of eating habits that indicated a link between high consumption of dairy products and a reduced risk of type 2 diabetes.
However, the new study indicates that it is high-fat dairy products specifically that are associated with reduced risk.
"Those who ate the most high-fat dairy products had a 23 per cent lower risk of developing type 2 diabetes than those who ate the least. High meat consumption was linked to an increased risk of type 2 diabetes ...
Researchers at the University of Warwick and UHCW have discovered how body clock genes could affect women's ability to have children.
The study, by medics at Warwick Medical School and University Hospitals Coventry and Warwickshire (UHCW) NHS Trust, pinpoints how body clock genes are temporarily switched off in the lining of the womb to allow an embryo to implant. Timing of this event is critical for pregnancy.
The researchers examined endometrial cells from womb linings of healthy women, and also biopsies from women who had sadly suffered from recurrent pregnancy ...
Egg consumption may reduce the risk of type 2 diabetes, according to new research from the University of Eastern Finland. The findings were published in American Journal of Clinical Nutrition.
Type 2 diabetes is becoming increasingly widespread throughout the world. Research has shown that lifestyle habits, such as exercise and nutrition, play a crucial role in the development of the disease. In some studies, high-cholesterol diets have been associated with disturbances in glucose metabolism and risk of type 2 diabetes. In contrast, in some experimental studies, the consumption ...
An illuminating study compares the willingness of stage IV cancer patients, and their caregivers; to pay to extend their lives by one year against that of other end-of-life improvements. The research, led by members of the Lien Centre for Palliative Care (LCPC) and collaborators from the National Cancer Centre Singapore, was recently published in the journal, Palliative Medicine.
Patients with advanced cancer or other life limiting illnesses often have to consider how much money they are willing to spend on high cost treatments that result in only moderate improvements ...
University of Adelaide researchers have shown there are two critical windows during the developmental pathway to adulthood when exposure to junk food is most harmful, particularly for female offspring.
This work leads on from earlier findings which showed that mothers who eat junk food while pregnant are programming their babies to be addicted to a high fat, high sugar diet by the time they are weaned.
Their latest laboratory studies reveal there may be a chance to turn around this junk food addiction in two critical windows--equating to late pregnancy and in adolescence ...
