LINER on collision course

Esahubble_potw2341a_1024

esahubble_potw2341a October 9th, 2023

Credit: ESA/Hubble & NASA, M. West

This Picture of the Week prominently features two galaxies: NGC 3558 in the lower left, and LEDA 83465 in the upper right. Both galaxies lie roughly 450 million light years from Earth. The two galaxies are separated from one another by a distance of roughly 150 000 light years, which might sound vast, until we consider that our nearest galactic neighbour — the Andromeda galaxy — is a whopping 2.5 million light years distant from the Milky Way galaxy. In galactic terms, the two galaxies pictured here are practically on top of one another. This is because they belong to a crowded and chaotic galaxy cluster known as Abell 1185, which is packed with galaxies that are interacting with one another via gravity. These galactic interactions have sometimes led to dramatic results, such as galaxies being torn apart completely. This fate has not befallen NGC 3558, which currently retains its integrity as both an elliptical galaxy and a low-ionisation nuclear emission-line region, or LINER. In fact, it probably attained its present form by devouring smaller galaxies in the cluster — galaxies much like LEDA 83465. LINERs are a particular type of galactic nucleus or core, and are distinguished by the chemical fingerprints written into the light that they emit. As their name suggests, LINERs emit light which suggests that many of the atoms and molecules within these galactic cores have either been weakly ionised or not ionised at all. Ionisation is the process by which atoms or molecules lose or gain electrons. In galaxies, it is driven by a variety of processes — from shockwaves travelling through galaxies, to radiation from massive stars or from hot gas in accretion discs. In the case of LINERs, this means that many of the atoms and molecules within the galaxies have lost either a single electron, or have retained all their electrons. The mechanism that drives this weak ionisation in LINERs such as NGC 3558 is still debated amongst astronomers.  [Image Description: Two galaxies are prominent among many much smaller background galaxies in the darkness of space. The larger galaxy is an elliptical galaxy, radiating light in a perfectly even sphere from a bright centre. The smaller galaxy is a barred spiral, with arms that are wispy like fog connected to a bar crossing the galaxy’s shining core. The shape of the arms makes the smaller galaxy notably squarish.]

Provider: Hubble Space Telescope | ESA

Image Source: https://esahubble.org/images/potw2341a/

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

Image Use Policy: Creative Commons Attribution 4.0 International License

Image Details

Image Type
Observation
Object Name
LEDA 83465 NGC 3558
Esahubble_potw2341a_128
 

Position Details

Position (ICRS)
RA = 11h 10m 55.2s
DEC = 28° 33’ 4.9”
Orientation
North is 32.4° CW
Field of View
3.4 x 3.2 arcminutes
Constellation
Ursa Major

Color Mapping

  Telescope Spectral Band Wavelength
Blue Hubble (ACS) Optical (g) 475.0 nm
Green Hubble (ACS) Optical (g) 475.0 nm
Green Hubble (ACS) Optical (I) 814.0 nm
Red Hubble (ACS) Optical (I) 814.0 nm
Spectrum_base
Blue
Green
Green
Red
Esahubble_potw2341a_1280
×
ID
potw2341a
Subject Category
Subject Name
LEDA 83465, NGC 3558
Credits
ESA/Hubble & NASA, M. West
Release Date
2023-10-09T06:00:00
Lightyears
Redshift
Reference Url
https://esahubble.org/images/potw2341a/
Type
Observation
Image Quality
Distance Notes
Facility
Hubble Space Telescope, Hubble Space Telescope, Hubble Space Telescope, Hubble Space Telescope
Instrument
ACS, ACS, ACS, ACS
Color Assignment
Blue, Green, Green, Red
Band
Optical, Optical, Optical, Optical
Bandpass
g, g, I, I
Central Wavelength
475, 475, 814, 814
Start Time
Integration Time
Dataset ID
None, None, None, None
Notes
Coordinate Frame
ICRS
Equinox
J2000
Reference Value
167.72991701709924, 28.55135497207984
Reference Dimension
4125.0, 3813.0
Reference Pixel
2062.5, 1906.5
Scale
-1.3890194878723799e-05, 1.3890194878723799e-05
Rotation
-32.400000000000048
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
potw2341a
Metadata Date
2023-09-22T13:30:07+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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