A dynamic duo … or trio?

Esahubble_potw2343a_1024

esahubble_potw2343a October 23rd, 2023

Credit: ESA/Hubble & NASA, J. Dalcanton, Dark Energy Survey/DOE/FNAL/NOIRLab/NSF/AURAAcknowledgement: L. Shatz  

This striking image captures the interacting galaxy pair known as Arp-Madore 2339-661, so named because they belong to the Arp-Madore catalogue of peculiar galaxies. However, this particular peculiarity might be even odder than first meets the eye, as there are in fact three galaxies interacting here, not just two.  The two clearly defined galaxies are NGC 7733 (smaller, lower right) and NGC 7734 (larger, upper left). The third galaxy is currently referred to as NGC 7733N, and can actually be spotted in this picture if you look carefully at the upper arm of NGC 7733, where there is a visually notable knot-like structure, glowing with a different colour to the arm and obscured by dark dust. This could easily pass as part of NGC 7733, but analysis of the velocities (speed, but also considering direction) involved in the galaxy shows that this knot has a considerable additional redshift, meaning that it is very likely its own entity and not part of NGC 7733. This is actually one of the many challenges that observational astronomers face: working out whether an astronomical object really is just one, or one lying in front of another as seen from Earth’s perspective! All three galaxies lie quite close to each other, roughly 500 million light-years from Earth in the constellation Tucana, and, as this image shows, they are interacting gravitationally with one another. In fact, some science literature refers to them as a ‘merging group’, meaning that they are on a course to ultimately become a single entity. [Image Description: Two spiral galaxies. Each glows brightly in the centre, where a bar stretches from side to side. The upper one is more round and its arms form two thin rings. The lower galaxy is flatter and its arms make one outer ring; a dusty knot atop its upper arm marks out a third object. Gravity is pulling gas and dust together where the galaxies come close. A number of small galaxies surround them on a black background.] Links Pan: A dynamic duo … or trio?

Provider: Hubble Space Telescope | ESA

Image Source: https://esahubble.org/images/potw2343a/

Curator: ESA/Hubble, Baltimore, MD, United States

Image Use Policy: Creative Commons Attribution 4.0 International License

Image Details

Image Type
Observation
Object Name
NGC 7733 NGC 7734
Esahubble_potw2343a_128
 

Position Details

Position (ICRS)
RA = 23h 42m 38.3s
DEC = -65° 57’ 3.7”
Orientation
North is 20.1° CW
Field of View
2.8 x 2.9 arcminutes
Constellation
Tucana

Color Mapping

  Telescope Spectral Band Wavelength
Blue Blanco-4m (DECam) Optical (G) 474.0 nm
Green Blanco-4m (DECam) Optical (R) 644.0 nm
Red Blanco-4m (DECam) Optical (Z) 919.0 nm
Luminosity Hubble (ACS) Optical (V) 606.0 nm
Spectrum_base
Blue
Green
Red
Luminosity
Esahubble_potw2343a_1280
×
ID
potw2343a
Subject Category
Subject Name
NGC 7733, NGC 7734
Credits
ESA/Hubble & NASA, J. Dalcanton, Dark Energy Survey/DOE/FNAL/NOIRLab/NSF/AURAAcknowledgement: L. Shatz  
Release Date
2023-10-23T06:00:00
Lightyears
Redshift
Reference Url
https://esahubble.org/images/potw2343a/
Type
Observation
Image Quality
Distance Notes
Facility
Víctor M. Blanco 4-meter Telescope, Víctor M. Blanco 4-meter Telescope, Víctor M. Blanco 4-meter Telescope, Hubble Space Telescope
Instrument
DECam, DECam, DECam, ACS
Color Assignment
Blue, Green, Red, Luminosity
Band
Optical, Optical, Optical, Optical
Bandpass
G, R, Z, V
Central Wavelength
474, 644, 919, 606
Start Time
Integration Time
Dataset ID
None, None, None, None
Notes
Coordinate Frame
ICRS
Equinox
J2000
Reference Value
355.6594395196239, -65.95102777918204
Reference Dimension
3347.0, 3522.0
Reference Pixel
1673.5, 1761.0
Scale
-1.389076922083906e-05, 1.389076922083906e-05
Rotation
-20.140000000000036
Coordinate System Projection:
TAN
Quality
Full
FITS Header
Notes
Creator (Curator)
ESA/Hubble
URL
https://esahubble.org
Name
Email
Telephone
Address
ESA Office, Space Telescope Science Institute, 3700 San Martin Dr
City
Baltimore
State/Province
MD
Postal Code
21218
Country
United States
Rights
Creative Commons Attribution 4.0 International License
Publisher
ESA/Hubble
Publisher ID
esahubble
Resource ID
potw2343a
Metadata Date
2023-10-04T01:12:06+02:00
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.

 

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