Hubble observes first multiple images of explosive distance indicator— Lensed supernova will give insight into the expansion of the Universe

Hubble observes first multiple images of explosive distance indicator.


Lensed supernova will give insight into the expansion of the Universe

A Swedish-led team of astronomers used the NASA/ESA Hubble Space Telescope to analyse the multiple images of a gravitationally lensed type Ia supernova for the first time. The four images of the exploding star will be used to measure the expansion of the Universe. This can be done without any theoretical assumptions about the cosmological model, giving further clues about how fast the Universe is really expanding. The results are published in the journal Science.

An international team, led by astronomers from the Stockholm University, Sweden, has discovered a distant type Ia supernova, called iPTF16geu [1] — it took the light 4.3 billion years to travel to Earth [2]. The light from this particular supernova was bent and magnified by the effect of gravitational lensing so that it was split into four separate images on the sky [3]. The four images lie on a circle with a radius of only about 3000 light-years around the lensing foreground galaxy, making it one of the smallest extragalactic gravitational lenses discovered so far. Its appearance resembles the famous Refsdal supernova, which astronomers detected in 2015 (heic1525). Refsdal, however, was a core-collapse supernova.

Type Ia supernovae always have the same intrinsic brightness, so by measuring how bright they appear astronomers can determine how far away they are. They are therefore known as standard candles. These supernovae have been used for decades to measure distances across the Universe, and were also used to discover its accelerated expansion and infer the existence of dark energy. Now the supernova iPTF16geu allows scientists to explore new territory, testing the theories of the warping of spacetime on smaller extragalactic scales than ever before.

“Resolving, for the first time, multiple images of a strongly lensed standard candle supernova is a major breakthrough. We can measure the light-focusing power of gravity more accurately than ever before, and probe physical scales that may have seemed out of reach until now,” says Ariel Goobar, Professor at the Oskar Klein Centre at Stockholm University and lead author of the study.

The critical importance of the object meant that the team instigated follow-up observations of the supernova less than two months after its discovery. This involved some of the world’s leading telescopes in addition to Hubble: the Keck telescope on Mauna Kea, Hawaii, and ESO’s Very Large Telescope in Chile. Using the data gathered, the team calculated the magnification power of the lens to be a factor of 52. Because of the standard candle nature of iPTF16geu, this is the first time this measurement could be made without any prior assumptions about the form of the lens or cosmological parameters.

Currently the team is in the process of accurately measuring how long it took for the light to reach us from each of the four images of the supernova. The differences in the times of arrival can then be used to calculate the Hubble constant — the expansion rate of the Universe — with high precision [4]. This is particularly crucial in light of the recent discrepancy between the measurements of its value in the local and the early Universe (heic1702).

As important as lensed supernovae are for cosmology, it is extremely difficult to find them. Not only does their discovery rely on a very particular and precise alignment of objects in the sky, but they are also only visible for a short time. “The discovery of iPTF16geu is truly like finding a somewhat weird needle in a haystack,” remarks Rahman Amanullah, co-author and research scientist at Stockholm University. “It reveals to us a bit more about the Universe, but mostly triggers a wealth of new scientific questions.”

Studying more similarly lensed supernovae will help shape our understanding of just how fast the Universe is expanding. The chances of finding such supernovae will improve with the installation of new survey telescopes in the near future.
Notes

[1] iPTF16geu was initially observed by the iPTF (intermediate Palomar Transient Factory) collaboration with the Palomar Observatory. This is a fully automated, wide-field survey delivering a systematic exploration of the optical transient sky.

[2] This corresponds to a redshift of 0.4. The lensing galaxy has a redshift of 0.2.

[3] Gravitational lensing is a phenomenon that was first predicted by Albert Einstein in 1912. It occurs when a massive object lying between a distant light source and the observer bends and magnifies the light from the source behind it. This allows astronomers to see objects that would otherwise be to faint to see.

[4] For each image of the supernova, the light is not bent in the same way. This results in slightly different travel times. The maximum time delay between the four images is predicted to be less than 35 hours.

Detailed look at a gravitationally lensed supernova

This composite image shows the gravitationally lensed type Ia supernova iPTF16geu, as seen with different telescopes. The background image shows a wide-field view of the night sky as seen with the Palomar Observatory located on Palomar Mountain, California. The leftmost image shows observations made with the Sloan Digital Sky Survey (SDSS). The central image was taken by the NASA/ESA Hubble Space Telescope and shows the lensing galaxy SDSS J210415.89-062024.7. The rightmost image was also taken with Hubble and depicts the four lensed images of the supernova explosion, surrounding the lensing galaxy.

Credit:

ESA/Hubble, NASA, Sloan Digital Sky Survey, Palomar Observatory/California Institute of Technology

Hubble’s view on lensing galaxy

The galaxy SDSS J210415.89-062024.7 is located 2.5 billion light years away. It acted as a lens for a supernova at an even greater distance, creating four distinct images of the explosion — an effect created by strong gravitational lensing.

Credit:
ESA/Hubble, NASA

Hubble’s view on lensed supernova



The supernova iPTF16geu exploded at a distance corresponding to a time 4.3 billion years ago. It could only be detected because a foreground galaxy lensed the light of the explosion, making it 50 times brighter for observers on Earth. It also caused the supernova to appear in four distinct places on the sky, surrounding the lensing galaxy in the foreground.

Credit:
ESA/Hubble, NASA

Palomar’s view on iPTF16geu


The Palomar Observatory, located on Palomar Mountain, California, created this wide-field view of the night sky. In the lower central part of the image scientists discovered a supernova explosion, being lensed by a foreground galaxy.

Credit:
ESA/Hubble, Palomar Observatory/California Institute of Technology

The SDSS view on iPTF16geu


Astronomers used the Sloan Digital Sky Survey (SDSS), carried out by a 2.5-metre wide-angle optical telescope at Apache Point Observatory in New Mexico, USA, to look for supernovae. The explosion named iPTF16geu can be seen left of the centre of the image as a tiny red dot.

Credit:

ESA/Hubble, Sloan Digital Sky Survey

Keck’s view on lensed supernova

The adaptive-optics instruments on the W.M. Keck Observatory on Mauna Kea, Hawaii, were able to resolve the supernova explosion iPTF16geu in detail.

Credit:

ESA/Hubble, W. M. Keck Observatory

Video .

Schematic of strong gravitational lensing


This animation shows the phenomenon of strong gravitational lensing. This effect caused the supernova iPTF16geu to appear 50 times brighter than under normal circumstances and to be visible on the sky four times.

Credit:

ESA/Hubble, L. Calçada

Hubblecast 70: Peering around cosmic corners


Last month saw the inauguration of a new Hubble observing program: Frontier Fields. This will use the powerful magnifying properties of massive galaxy clusters to peer even deeper into the space around us. Hubblecast 70 takes a look at this phenomenon — known as gravitational lensing — exploring how it works, and how it can help us to uncover the secrets of the very distant Universe.

Find out how to view and contribute subtitles for the Hubblecast in multiple languages, or translate this video on dotSUB.

Credit:

ESA/Hubble

Directed by: Nicola Guttridge
Visual design and editing: Martin Kornmesser
Written by: Nicola Guttridge & Georgia Bladon
Presented by: Joe Liske (Dr J)
Narration: Sara Mendes da Costa
Images and animations: ESA/Hubble, NASA, Martin Kornmesser

    Clips from Hubble IMAX 3D video “Hubble: Galaxies Across Space and Time”. Credit: NASA, ESA and F. Summers (STScI)
    The Hubble Deep Fields
    Milky Way animation, gravitational lens animations: M. Kornmesser
    Gravitational lensing in action: NASA, ESA & L. Calçada
    Image of Abell 383 (heic1106a): NASA, ESA, J. Richard (CRAL) and J.-P. Kneib (LAM). Acknowledgement: Marc Postman (STScI)
    Image of Abell 1689 (heic1317a): NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Blakeslee (NRC Herzberg Astrophysics Program, Dominion Astrophysical Observatory), and H. Ford (JHU)
    Abell 370 (heic0910b): NASA, ESA, the Hubble SM4 ERO Team and ST-ECF
    Abell 2218 (heic0814a): NASA, ESA, and Johan Richard (Caltech, USA). Acknowledgement: Davide de Martin & James Long (ESA/Hubble)
    RCS2 032727-132623 (opo1208a): NASA, ESA, J. Rigby (NASA Goddard Space Flight Center), K. Sharon (Kavli Institute for Cosmological Physics, University of Chicago), and M. Gladders and E. Wuyts (University of Chicago)
    Images of Einstein rings (heic0806): NASA, ESA, C. Faure (Zentrum für Astronomie, University of Heidelberg) and J.P. Kneib (Laboratoire d'Astrophysique de Marseille)
    Images of double ring (heic0803): NASA, ESA, R. Gavazzi and T. Treu (University of California, Santa Barbara), and the SLACS team
    Gravitational telescope creates space invader mirage (heic1304). NASA & ESA. Acknowledgement: N. Rose
    Hubble captures a 'five-star' rated gravitational lens (heic0606): European Space Agency, NASA, Keren Sharon (Tel-Aviv University) and Eran Ofek (CalTech)

Music: John Stanford (johnstanfordmusic.com)
Web and technical support: Mathias Andre and Raquel Yumi Shida
Cinematography: Peter Rixner (www.perix-media-gmbh.de)
Executive producer: Lars Lindberg Christensen


Fuente: ESA/Hubble Information Centre

Comentarios

Entradas populares de este blog

Las 3 banderas de Chile

FALLECE ROY GARBER, UNO DE LOS PROTAGONISTAS DE LA SERIE “GUERRA DE ENVÍOS” EN A&E

Falleció hija de dos años de la periodista Mónica Rincón.Clara Galdames dejó de existir en horas de esta mañana, tras llevar días internada en la UTI por problemas al corazón. La niña había presentado complicaciones físicas desde su nacimiento.