Gaia discovers its first supernova

 

Date: 12 September 2014

Original link: ESA webpage

While scanning the sky to measure the positions and movements of stars in our Galaxy, Gaia has discovered its first stellar explosion in another galaxy far, far away.

 

An artist’s impression of a Type Ia supernova – the explosion of a white dwarf locked in a binary system with a companion star. While other types of supernovas are the explosive demises of massive stars, several times more massive than the Sun, Type Ia supernovas are the end product of their less massive counterparts. Low-mass stars, with masses similar to the Sun’s, end their lives gently, puffing up their outer layers and leaving behind a compact white dwarf. Due to their high density, white dwarfs can exert an intense gravitational pull on a nearby companion star, accreting mass from it until the white dwarf reaches a critical mass that then sparks a violent explosion. Credit: ESA/ATG medialab/C. Carreau

This powerful event, now named Gaia14aaa, took place in a distant galaxy some 500 million light-years away, and was revealed via a sudden rise in the galaxy’s brightness between two Gaia observations separated by one month.

 

Gaia, which began its scientific work on 25 July, repeatedly scans the entire sky, so that each of the roughly one billion stars in the final catalogue will be examined an average of 70 times over the next five years.

 

“This kind of repeated survey comes in handy for studying the changeable nature of the sky,” comments Simon Hodgkin from the Institute of Astronomy in Cambridge, UK.

 

Many astronomical sources are variable: some exhibit a regular pattern, with a periodically rising and declining brightness, while others may undergo sudden and dramatic changes.

 

“As Gaia goes back to each patch of the sky over and over, we have a chance to spot thousands of ‘guest stars’ on the celestial tapestry,” notes Dr Hodgkin. “These transient sources can be signposts to some of the most powerful phenomena in the Universe, like this supernova.”

 

Dr Hodgkin is part of Gaia’s Science Alert Team, which includes astronomers from the Universities of Cambridge, UK, and Warsaw, Poland, who are combing through the scans in search of unexpected changes.

 

It did not take long until they found the first ‘anomaly’ in the form of a sudden spike in the light coming from a distant galaxy, detected on 30 August. The same galaxy appeared much dimmer when Gaia first looked at it just a month before.

Light curve of galaxy SDSS J132102.26+453223.8 obtained with Gaia. It shows the evolution in time of the galaxy’s brightness. The brightness is indicated on the vertical axis; smaller magnitude values indicate a brighter source. The light curve shows how the galaxy significantly brightened up between the two consecutive Gaia observations because of a stellar explosion, or supernova, which was named Gaia14aaa. This is the first supernova discovered with Gaia. The data points and error bars at the lower left corner are from the first observation, performed on 31 July 2014, and they are in line with previous observations of the same galaxy performed with other telescopes. The data points at the upper right corner are from the second observation, performed on 30 August 2014, and reveal a sudden rise in brightness of almost two magnitudes (roughly a factor of 6). Using data from Gaia and other telescopes, astronomers confirmed that Gaia14aaa is a Type Ia supernova, the explosion of a white dwarf caused by the accretion of matter from a companion star in a binary system. Credits: ESA/Gaia/DPAC/Z. Kostrzewa-Rutkowska (Warsaw University Astronomical Observatory) & G. Rixon (Institute of Astronomy, Cambridge)

“We immediately thought it might be a supernova, but needed more clues to back up our claim,” explains Łukasz Wyrzykowski from the Warsaw University Astronomical Observatory, Poland.

 

Other powerful cosmic events may resemble a supernova in a distant galaxy, such as outbursts caused by the mass-devouring supermassive black hole at the galaxy centre.

 

However, in Gaia14aaa, the position of the bright spot of light was slightly offset from the galaxy’s core, suggesting that it was unlikely to be related to a central black hole.

So, the astronomers looked for more information in the light of this new source. Besides recording the position and brightness of stars and galaxies, Gaia also splits their light to create a spectrum. In fact, Gaia uses two prisms spanning red and blue wavelength regions to produce a low-resolution spectrum that allows astronomers to seek signatures of the various chemical elements present in the source of that light.

 

“In the spectrum of this source, we could already see the presence of iron and other elements that are known to be found in supernovas,” says Nadejda Blagorodnova, a PhD student at the Institute of Astronomy in Cambridge.

 

Low-resolution spectrum obtained with the photometric instrument on Gaia of a stellar explosion, or supernova. Astronomers using Gaia discovered that a source had significantly brightened up between two consecutive observations, performed on 31 July 2014 and 30 August 2014, respectively. The boost in brightness was caused by a supernova, which was named Gaia14aaa. This is the first supernova discovered with Gaia. The photometric instrument splits the light of an astronomical source to create a spectrum. In fact, Gaia uses two prisms spanning red and blue wavelength regions to produce a low-resolution spectrum that allows astronomers to seek signatures of the various chemical elements present in the source of that light. Light from the blue photometer is shown in the left half of the graph, and that from the red photometer in the right half. On the horizontal axis, the position of pixels in each of the two photometers is indicated. The pixel position provides a rough indication of the wavelength, with the blue photometer receiving light with shorter wavelengths (330–680 nanometres), and the red photometer with longer wavelengths (640–1050 nanometres). On the vertical axis, the intensity of light registered at each pixel is indicated. The gap at the centre of the graph is an instrumental effect. This low-resolution spectrum contains hints about the nature of this transient source. The blue part of the spectrum appears significantly brighter than the red one, as expected from a supernova of Type Ia – the explosion of a white dwarf caused by the accretion of matter from a companion star in a binary system. The presence of absorption lines from iron, sulphur, oxygen and calcium (indicated in the graph) is also in line with the elements expected from a Type Ia supernova. The astronomers followed up this source with the Isaac Newton Telescope on La Palma, in the Canary Islands, Spain, obtaining a high-resolution spectrum. This not only confirmed that the explosion corresponds to a Type Ia supernova, but also provided an estimate of its distance, proving that it actually happened in the galaxy where it was observed. Credits: ESA/Gaia/DPAC/N. Blagorodnova, M. Fraser, H. Campbell, A. Hall (Institute of Astronomy, Cambridge)

 

In addition, the blue part of the spectrum appears significantly brighter than the red part, as expected in a supernova. And not just any supernova: the astronomers already suspected it might be a ‘Type Ia’ supernova – the explosion of a white dwarf locked in a binary system with a companion star.

 

While other types of supernovas are the explosive demises of massive stars, several times more massive than the Sun, Type Ia supernovas are the end product of their less massive counterparts.

 

Low-mass stars, with masses similar to the Sun’s, end their lives gently, puffing up their outer layers and leaving behind a compact white dwarf. Their high density means that white dwarfs can exert an intense gravitational pull on a nearby companion star, accreting mass from it until the white dwarf reaches a critical mass that then sparks a violent explosion.

 

To confirm the nature of this supernova, the astronomers complemented the Gaia data with more observations from the ground, using the Isaac Newton Telescope (INT) and the robotic Liverpool Telescope on La Palma, in the Canary Islands, Spain.

 

This image shows the supernova named Gaia14aaa as seen on 10 September 2014 with the robotic Liverpool Telescope on La Palma, in the Canary Islands, Spain. This is a Type Ia supernova – the explosion of a white dwarf locked in a binary system with a companion star – and it was discovered in the data collected with ESA’s Gaia satellite on 30 August. In the left panel, the image from the Liverpool Telescope shows both Gaia14aaa and its host galaxy, named SDSS J132102.26+453223.8, which is about 500 million light-years away. In this image, the supernova is slightly offset from the galaxy’s core. The central panel shows an image of the same galaxy, taken as part of the Sloan Digital Sky Survey, several years before the explosion of Gaia14aaa could be observed from Earth. The right panel was obtained by subtracting the second image, which contains the light emitted by the galaxy, from the first one, which depicts both the galaxy and the supernova. The difference between the two images clearly shows the appearance of Gaia14aaa. The image was taken using the i' filter, which corresponds to red and near-infrared wavelengths. Credit: M. Fraser/S. Hodgkin/L. Wyrzykowski/H. Campbell/N. Blagorodnova/Z. Kostrzewa-Rutkowska/Liverpool Telescope/SDSS

A high-resolution spectrum, obtained on 3 September with the INT, confirmed not only that the explosion corresponds to a Type Ia supernova, but also provided an estimate of its distance. This proved that the supernova happened in the galaxy where it was observed.

 

“This is the first supernova in what we expect to be a long series of discoveries with Gaia,” says Timo Prusti, ESA’s Gaia Project Scientist.

 

Supernovas are rare events: only a couple of these explosions happen every century in a typical galaxy. But they are not so rare over the whole sky, if we take into account the hundreds of billions of galaxies that populate the Universe.

 

Astronomers in the Science Alert Team are currently getting acquainted with the data, testing and optimising their detection software. In a few months, they expect Gaia to discover about three new supernovas every day.

 

In addition to supernovas, Gaia will discover thousands of transient sources of other kinds – stellar explosions on smaller scale than supernovas, flares from young stars coming to life, outbursts caused by black holes that disrupt and devour a nearby star, and possibly some entirely new phenomena never seen before.

 

“The sky is ablaze with peculiar sources of light, and we are looking forward to probing plenty of those with Gaia in the coming years,” concludes Dr Prusti.

 

 

Remember that you can follow all Gaia updates and news from our GaiaApp

gaiaAppEn

sales marketing and sample for cv math fractions homework multiplying help dissertation vs thesis meaning writing cv services xertigny informative my to speech what do on english essay help to write an how i much pay someone essay should and in the rebel without catcher essay rye a logistics cause thesis green paper cyanotype uk sale for online spanish help homework buy acquista a prescription - Fort best priced Floxin Floxin reasonably Lauderdale without research papers custom solutions statistics order homework reflective is person first essay written a in population the malthus principle thomas of an essay on a resume how look should best essay homework french do my resume services chicago reviews best writing essays college application need for titles sale hire biography for writers mla authors with two bibliography annotated shipping prescription no delivery buy gold free fly research paper pay forward it ph school homework help custom reviews servie customer writtings on my online proofread essay questions toefl essay reading homework helper writing kitchener services resume writer cheap dissertation writing to civilian resume military service critical analysis do thesis help engineering mechanical moment homework bending in dissertation of terms definition key help for america essay teach accounting homework help with online writing vans cheap dissertation homework grade for help 6 volunteer homework sydney help coursework art help library center homework help i where purchase cheap no script peo can health cannot money buy essay plan with help business writing a free craig gordon essay teachers edward writing report resume denver help dissertation verlag publizieren what extended my can i do on essay paper writen custom term discount ketorol free shipping no prescription delivery elemantery homework help online Zantac buy essays buy papers term online patch deliverey penis growth fast online help homework university research online companies writing made usa chondro-ritz in my help homework i music need with reviews service better resume writing a education thesis chapter girl short freakonomics essay on child of 6 my need thesis i write to someone dissertation and dummies help for proposal cpm homework algebra 1 help conclusion disorder anxiety essay resume med for school when make to high in a resume school how essay about and cleanliness orderliness how essay introduction education school yourself for public and private to letter an write about cc1 cpm help homework service finance writing cv adalat ausschleichen cured loss weight resume purchase for rivers woodlands homework school junior help south order africa paper online writing essay services business for papers sale university custom writings services help 24 government 7 homework live homework help hulman rose and nj resume services writing professional with uni assignment need help physics online homework help hiring address committee letter to cover sale uk retard sleepwell azimac no percription mg 400 resume in engineer sample for mechanical construction plan southern house cottage for homework paid get help help statistics homework writing nyc services i can myself my encourage homework how do to introduction essay and juliet romeo writing essay review services custom best homework help live online sample medical for assistant administrative cover letters sample estate letter purchase real to of intent compulsive ppt obsessive disorder presentation accounting do pay homework to someone best service essay structure dissertation masters services letter for outstanding medical recommendation students essay and money happiness online programs cheapest phd english high reading proof and online papers school college help college essay admission common i my write in japanese name how do dissertation service custom it writing essay and the is best peru yahoo haya dating chile for coding specialist resume medical pakistani sites essay homework help functions transformations writers paper essay cheap written papers pre research pharmacy sale silvo vigora help mba homework economics london services in work course dissertation help heroes homework california help homework resume online best writing services australia for a speech how write vote to me Evecare mg - england buy sale for 1 Birmingham of Evecare writing doctoral eden help dissertation homework java help script sociology buy paper research paper mozart research on homework accounting help financial help black the woman in essay professional island services online long writing resume worldwide zoloft online free shipping sport autobiography supercharged for 2012 range rover sale for kids creative websites writing put for assistant skills medical good resume on a to do should my i who paper research on taking in dissertation academic adolescent risk to essays help write dyslexic for help students homework my do work course south plan writer africa business essay college help connecticut sample assistants for letters cover medical writing university paper services white and brian management skills business students for dissertation outline paper big essay on pollution discussion research plan national esf8 food genetically modified background homework government helper homework scientific help notation online Levitra Professional purchase papers for philosophy sale helpers homework history us level essay help french can order rx how without flovent i help cs assignment help biology homework ap lab per pill Detrol - sale Columbus product Detrol price online freud papers how a statement for personal mechanical write engineering to thesis phd safety townie buy essays online dissertation size reduction on class demonstrate her teresa how kindness illustrate mother fast yagara delivery service write good application college essay cv first i do how write my lotrisone for free 25mg mental resume health for sample therapist cam dating gigandet great personal essays to letters in korean write name how my university help essay manchester stopping physics the of and adolf conflict of case rise essay hitler fall management analysis study michigan arbor resume writing services ann to do paper my pay dissertation musikwissenschaft help admission vocabulary college essay dating method 206 uranium lead to 238 with help words to essays papers kidney disorders therapy radiation research plan business buy sell assignment malaysia help mba on marriage essay definition compare a essay contrast and dating madness uk singles google helper homework brand dosage Berkeley - Septilin Septilin help uk online assignment where no can fees no prescription i keftab purchase written essays wolfe by tom c iit resume unix phd essays law buy writing tip paper term london writing dissertation custom help uk accounting assignment lined paper writing online copegus dallas online essays custom resume on admission for counselors objectives