An echo of light

Eso_potw1814a_1024

eso_potw1814a April 2nd, 2018

Credit: ESO Acknowledgements: P. Merluzzi (INAF-Osservatorio Astronomico di Capodimonte, Italy)

This unique image from ESOs VLT Survey Telescope (VST) reveals two galaxies at the very beginning of the merging process. The interactions between the duo have created a rare effect known as a light echo, where light reverberates around the material within each galaxy. This is analogous to the acoustic echo where the reflected sound arrives at the listener with a delay after the direct sound. This is the first case of a light echo observed between two galaxies. The larger galaxy, seen here in yellow, is ShaSS 073 an active galaxy with an extremely luminous core. Its less massive companion, in blue, is named ShaSS 622, and together the pair make up the intriguing ShaSS 622-073 system. The bright core of ShaSS073 is exciting a region of gas within the disc of its blue companion: it bombards the material there with radiation, causing it to glow brightly as it absorbs and then re-emits this light. This glowing region extends across 1.8 billions of square light-years. However, while studying this merger, astronomers found the luminosity of the large central galaxy to be 20 times lower than needed to excite the gas in this way. This indicates that the centre of ShaSS073 has dramatically faded over the last 30000 years or so but the highly-ionised region between the two galaxies still retains the memory of its former glory. Links Annotated version Paper by Merluzzi et al.

Image Source: https://www.eso.org/public/images/potw1814a/

Curator: European Southern Observatory, Garching bei München, Germany

Image Use Policy: Creative Commons Attribution 4.0 International License

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Image Details

Image Type
Observation
Object Name
ShaSS 073 ShaSS 622 ShaSS 622-073
Subject - Local Universe
Galaxy > Type > Interacting
Eso_potw1814a_128
 

Position Details

Position (ICRS)
RA = 13h 16m 32.6s
DEC = -31° 12’ 26.6”
Orientation
North is 0.2° CCW
Field of View
10.5 x 7.0 arcminutes
Constellation
Centaurus

Color Mapping

  Telescope Spectral Band Wavelength
Arrow_left_blue VLT Survey Telescope (OmegaCAM) Optical (g) 480.0 nm
Arrow_left_green VLT Survey Telescope (OmegaCAM) Optical (r) 625.0 nm
Arrow_left_red VLT Survey Telescope (OmegaCAM) Optical (i) 770.0 nm
Spectrum_base
Arrow_top_blue
Arrow_top_green
Arrow_top_red
Eso_potw1814a_1280
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ID
potw1814a
Subject Category
C.5.1.7  
Subject Name
ShaSS 073, ShaSS 622, ShaSS 622-073
Credits
ESO Acknowledgements: P. Merluzzi (INAF-Osservatorio Astronomico di Capodimonte, Italy)
Release Date
2018-04-02T06:00:00
Lightyears
Redshift
Reference Url
https://www.eso.org/public/images/potw1814a/
Type
Observation
Image Quality
Distance Notes
Facility
VLT Survey Telescope, VLT Survey Telescope, VLT Survey Telescope
Instrument
OmegaCAM, OmegaCAM, OmegaCAM
Color Assignment
Blue, Green, Red
Band
Optical, Optical, Optical
Bandpass
g, r, i
Central Wavelength
480, 625, 770
Start Time
Integration Time
Dataset ID
Notes
Coordinate Frame
ICRS
Equinox
J2000
Reference Value
199.135825335, -31.2073856946
Reference Dimension
3000.0, 2000.0
Reference Pixel
1429.0, 1391.0
Scale
-5.8296593347318428E-05, 5.8296593347318428E-05
Rotation
0.18
Coordinate System Projection:
TAN
Quality
Position
FITS Header
Notes
Creator (Curator)
European Southern Observatory
URL
http://www.eso.org
Name
Email
Telephone
Address
Karl-Schwarzschild-Strasse 2
City
Garching bei München
State/Province
Postal Code
D-85748
Country
Germany
Rights
Creative Commons Attribution 4.0 International License
Publisher
European Southern Observatory
Publisher ID
eso
Resource ID
potw1814a
Metadata Date
2018-03-24T18:36:33+01:00
Metadata Version
1.1
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Detailed color mapping information coming soon...

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There is no distance meta data in this image.