Blue Compact Dwarf Galaxies (BCDs) (Gary Imm)

Blue Compact Dwarf Galaxies (BCDs)

This poster is a compilation of Blue Compact Dwarf Galaxies (BCDs).

Despite some recent efforts, the criteria for identifying a BCD have not yet been widely established. In general, BCDs have the following characteristics:
1. Small (generally from 5000 to 15000 light years in diameter
2. Star-forming (generally blue in color)
3. No spiral disk structure
4. Bright blue and diffuse core
5. Contain little dust and no dust bands
6. Located close to us (they are faint and hard to identify at a distance)

I have not included a few more popular objects like IC10 which are questionable in their BCD status.

Gas (hydrogen plus helium) contributes to the majority of the mass of BCDs. Many scientists believe that these small, active galaxies serve as the building blocks for larger galaxy formation.

If you would like to read more about any of these objects, each of the objects in the poster has previously been uploaded and described individually on Astrobin. They all reside in my Astrobin Blue Compact Dwarf (BCD) Galaxy Collection.

If you would like to access all my DSO compilation posters, please click here.

CMOS Imagers
Cloudy Nights
Themed Compilation Posters

BCD (Blue Compact Dwarf) Galaxies
Galaxy Type Posters
Galaxy Types

Please note: The following tables are updated every 24 hours.

Distribution of astrophotographers

This table shows the number of distinct astrophotographers who have been assigned and IOTD/TP award compared to the total number of images awarded.
	Distinct awarded users	Total awarded images
Image of the day
Top picks
Top pick nominations

Distribution of subject types

This table shows the distribution of awards per subject type, compared to the popularity of images of that subject type.
	Image of the day	Top pick	Top pick nominations	Total submitted
Deep sky
Solar system
Extremely wide field
Star trails
Northern lights
Noctilucent clouds
Landscape

Distribution of data sources

This table shows the distribution of awards per data source, compared to the popularity of images acquired from that data source.
	Image of the day	Top pick	Top pick nominations	Total submitted
Backyard
Traveller
Own remote observatory
Amateur hosting facility
Public amaeteur data
Professional, scientific grade data
Mix of multiple sources
Other
Unknown

The “AstroBin Image of the Day and Top Picks”, or IOTD/TP, is a long-running system to promote beautiful, interesting, peculiar, or otherwise amazing astrophotographs, with a focus on technical excellence. Learn more.

Submitted The date and time when you submitted this image for IOTD/TP consideration.	...
Views by Submitters (available since September 19th, 2023) Every image is assigned to 50% of available Submitters. In the event that at least 80% of them don't view the image before its time in the IOTD/TP process expires, it's assigned to the other 50% of Submitters and the process begins anew.
Promotions by Submitters When 3 distinct Submitters promote the image, it moves on to the next stage of the process: evaluation for Top Pick status. This requirement, in addition to anonymization of images and distribution to only a subset of them, prevents biases and ensures that the best images are selected.
Promotions by Reviewers When 3 distinct Reviewers promote the image, it moves on to the next stage of the process: evaluation for IOTD status.
Early dismissal Staff members have a lot of images to inspect on a daily basis, and they can dismiss images if they believe they don't meet the requirements for IOTD/TP selection. If an image is dismissed 5 times, it's removed from the process. This streamlines the process and ensures that any bias present in promotions could be overruled by other staff members.

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