NGC 6822

Ensci_euclid20231107b_1024

ensci_euclid20231107b November 7th, 2023

Credit: ESA/Euclid/Euclid Consortium/NASA

To create a 3D map of the Universe, Euclid will observe the light from galaxies out to 10 billion light-years. Most galaxies in the early Universe don’t look like the quintessential neat spiral, but are irregular and small. They are the building blocks for bigger galaxies like our own, and we can still find some of these galaxies relatively close to us. This first irregular dwarf galaxy that Euclid observed is called NGC 6822 and is located close by, just 1.6 million light-years from Earth.

Technical details: The data in this image were taken in just about one hour of observation. This color image was obtained by combining VIS data and NISP photometry in Y and H bands; its size is 8800 x 8800 pixels. VIS and NISP enable observing astronomical sources in four different wavelength ranges. Aesthetics choices led to the selection of three out of these four bands to be cast onto the traditional Red-Green-Blue color channels used to represent images on our digital screens (RGB).

The blue, green, red channels capture the Universe seen by Euclid around the wavelength 0.7, 1.1, and 1.7 micron respectively. This gives Euclid a distinctive color palette: hot stars have a white-blue hue, excited hydrogen gas appears in the blue channel, and regions rich in dust and molecular gas have a clear red hue. Distant redshifted background galaxies appear very red.

In the image, the stars have six prominent spikes due to how light interacts with the optical system of the telescope in the process of diffraction. Another signature of Euclid special optics is the presence of a few, very faint and small round regions of a fuzzy blue color. These are normal artifacts of complex optical systems, so-called ‘optical ghost’; easily identifiable during data analysis, they do not cause any problem for the science goals.

ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi, CC BY-SA 3.0 IGO

Provider: Euclid

Image Source: https://euclid.caltech.edu/image/euclid20231107b-ngc-6822

Curator: Euclid-ESA

Image Use Policy: http://www.esa.int/spaceinvideos/Terms_and_Conditions

Image Details

Image Type
Observation
Object Name
NGC 6822
Subject - Local Universe
Galaxy > Type > Irregular

Distance

Universescale2
1,600,000 light years
Ensci_euclid20231107b_128
 

Position Details

Position (ICRS)
RA = 19h 44m 56.7s
DEC = -14° 47’ 16.4”
Orientation
North is 374.7° CCW
Field of View
41.0 x 41.0 arcminutes
Constellation
Sagittarius

Color Mapping

  Telescope Spectral Band Wavelength
Blue Euclid (VIS) Optical 700.0 nm
Green Euclid (NISP) Infrared 1.1 µm
Red Euclid (NISP) Infrared 1.7 µm
Spectrum_base
Blue
Green
Red
Ensci_euclid20231107b_1280
×
ID
euclid20231107b
Subject Category
C.5.1.6.  
Subject Name
NGC 6822
Credits
ESA/Euclid/Euclid Consortium/NASA
Release Date
2023-11-07
Lightyears
1,600,000
Redshift
1,600,000
Reference Url
https://euclid.caltech.edu/image/euclid20231107b-ngc-6822
Type
Observation
Image Quality
Good
Distance Notes
Facility
Euclid, Euclid, Euclid
Instrument
VIS, NISP, NISP
Color Assignment
Blue, Green, Red
Band
Optical, Infrared, Infrared
Bandpass
Central Wavelength
700, 1100, 1700
Start Time
Integration Time
Dataset ID
Notes
Coordinate Frame
ICRS
Equinox
Reference Value
296.23626844920233, -14.7878760760105
Reference Dimension
3000, 3000
Reference Pixel
1500, 1500
Scale
-0.00022785, 0.00022785
Rotation
374.707
Coordinate System Projection:
TAN
Quality
Full
FITS Header
Notes
Creator (Curator)
Euclid-ESA
URL
https://www.esa.int/Science_Exploration/Space_Science/Euclid
Name
Email
Telephone
Address
City
State/Province
Publisher
Euclid NASA Science Center at IPAC (ENSCI)
Publisher ID
ensci
Resource ID
Metadata Date
2023-11-21T19:49:24Z
Metadata Version
1.2
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Detailed color mapping information coming soon...

×
Universescalefull
1,600,000 light years

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