Colours of Galaxies in SDSS : Redshift chart

[Budgieye]

This chart was created when Galaxy Zoo 2 was using SDSS dr7 data. It will not work for Hubble Zoo.
Different types of galaxies have different colours. The colour of the galaxy changes with distance away (redshift) too.
Galaxies that have several of these characteristics are discussed at the end. There is a table of redshifts and colour at the end.

The following charts have clickable images of a sample of galaxies.  The types of objects are:
ellipticals - produce white light, from white stars
spirals - produce blue light from blue stars
compacts - produce ultraviolet light (UV) from young stars (star-forming galaxies)
OIII objects - produce emission lines from hot oxygen
active nuceus - produce emission lines from hot hydrogen (Hα emissions)

[Budgieye]

older stars	younger stars	star-forming UV	OIII emissions	Hα emissions
0.000 white star 587739406764474539	0.000 blue star 587741602026422330	0.0 young star nebula no ObjId HH25 (Herbig-Haro) Wolf-Rayet nebula ignore centre star LizPeter	0.000 planetary nebula 587731870705057817 M97 Owl Nebula ignore centre star LizPeter	0 supernova remnant 587738067267813400 ignore centre star LizPeter
0.003 elliptical 587726032790093907 zookeeper_anze	0.001spiral arm 587735665842389066 Pinwheel galaxy LankyYankee	0.002 587733605328355347 posted by c_cld	0.001 blue Compact 587735695913386093 quarkspin	0.001"wind" in M82 587738067813859388 Alice
0.004  elliptical 588017991757987991 IC 3518 elizabeth	0.018 blue 588015510349611150 UGC 00618 elizabeth	0.005 Blue Compact 588009370691567769 posted by Bruno	0.005 587732483816423467 UGCA 216 j_doe	0.005 587734892211142692 Markarian  731 Rick Nowell
0.015 elliptical 587739406804189307 Mukund Vedapudi	0.018 spiral 588015510349611150 UGC 00618 elizabeth	0.013 blue compact 587725469061283965 posted by Ioannab	0.010 blue pea 587738409789751347 laihro	0.008 green nucleus 587731868561244241 NGC 4194 Medusa merger elisabeth
0.027 elliptical 588016891173208111 waveney	0.027 spiral 587738946131722387 RandyC	0.028 compact 587738952034025563 posted by djj	0.026 587732484357161015 MRK 1448 Halibut	0.021 green nucleus 587738569786458210 Markarian 0796 Rick Nowell
0.038 lenticular 587733429234237557 IC 1069 posted by marhorr	0.037 spiral 588017702954270962 echo-lily-mai	0.030 587734862144077998 c_cld	0.03 Blue Compact 587739609155633199 linguist	0.034 quasar with jet 587739720846934175 laithro
0.048 elliptical 587722983898742801 Geoff	0.048 spiral 587732050557927478 marty	0.042 compact 587739407859122369 mitch	0.042 blue pea 588009366395879490 SHOC 220 posted fluffy porcupine	0.047 QSO 587726879424839709 Rick Nowell
0.053 elliptical 587736752468459681 posted by Gary	0.057 spiral 588023045873205432 elisabeth	0.056 compact 587730848502644768 Quialiss	0.058 purple pea 587734948052598924 posted by mitch	0.050 Seyfert 1 588017726554767455 Markarian 1347 elisabethB
0.068 elliptical 588017565487595596 waveney	0.069 spiral 587728668804644919 Mukund Vedapudi	0.064 compact 587733608016969915 echo-lily-mai	0.076 purple pea 587735346962497616 posted by sdrew123	0.067 Seyfert1 587742773491531836 elisabethB
0.077 elliptical 587733603718987891	0.072 spiral 587742014901452957 RandyC	0.071 compact 588017730302312588 c_cld	0.077 purple pea 587742013267771528 posted by Karma	0.077 Seyfert 1 587739504478060626 marcelv
0.084 elliptical 587741722823557218	0.086 spiral 588017979980906569 RandyC	0.080 compact 587731186207621250 StephanieC	0.082 purple pea 587727179003723785 starry nite	0.085 active nucleus 587736809916399664 fluffy porcupine
0.094 elliptical? 587736976883908844	0.093 spiral 588017705070100577 posted by Marcus2	~0.9 compact 587742775634296930 MRK 1317 Rick Nowell	0.093 purple pea 588017605228298342 posted by Alice	0.096 Seyfert  587732483819962452 Markarian 1447 Rick Nowell MRK list

[Budgieye]

older stars	younger stars	star-forming UV	OIII emission	Hα emission
0.132 elliptical 587730847428510150	0.165 spiral 588016891171635444 NGC3314/waveney	0.150 compact 587725980152758406 spiralmania	0.148 white pea 587731680116867174 starry nite	0.123 Seyfert 1 588007003629813783 Rick Nowell
0.24 elliptical 587735665306763364 c_cld, from  Hubble	0.199 587742014352326759 posted by Karakara	0.201 starburst 588297863119896669 ElisabethB	0.247 green pea 587724234248552589 posted by Hanny	0.229 quasar 587741491445432393 codexluminati
0.362 elliptical? 587725492134805936 jpodkow	0.29 barred spiral 588011123577651640 elizabeth	0.376 green starburst 587745244158427307 posted by mitch	0.312 green pea 587736915687964980 ccardamone's list pea hunters	0.330 blue quasar 587722984435089476 volare09
0.452 luminous red 587733412060987606 gumbosea	~0.4 spiral? 587735348022477078 posted by elisabethB also see h.kohler	0.476 green starburst 587732701783589053 posted by Hrundi	0.469 yellow pea 587726033846599793 laihro,red pea 0.484	0.435 blue quasar 587741391037005841 Bruno
0.558 elliptical? 587741600957333763 ElisabethB	0.5 barred spiral 587726032772530922 by c_cld, from Hubble	0.50 yellow starburst 587744728761172273 posted by mitch	0.587 red pea 587728932419076622 djj	0.588 blue quasar 587725505559920842 Bruno
0.641 elliptical? 587732470925886144 sayonave08	0.640 radio source 587731512082563479 posted by mitch	0.57 starburst? 587732583666286811 c_cld	0.635 red pea 588018056184529107 posted by starry nite	0.609 blue quasar 587739827137478733 erratton
0.702 radio source 587733603183952437 posted by mitch	0.7 barred spiral 587727944571028350 c_cld, from  Hubble	0.75 starburst? 587730774947594643 c_cld	0.732 red pea? 587726013998104775 posted by starry nite	0.767 blue quasar 587726102559457397 oswego9050
0.884 588017978355745177 posted AlexandredOr	0.81 spiral 587735664769827267 c_cld, from  Hubble	0.799 lensed starburst 587724650875453828	0.810 red pea ? 587733399189914218 posted by Solarsonja	0.887 blue quasar 587731173844975962 Bruno
0.920? 588010359612506196 posted by mitch	0.91 spiral 587735695377694972 c_cld, from  Hubble	0.996 purple arc 587733412060987609 gumbosea	0.935 red pea? 587739295087657110 "pea hunters list"	0.954 blue quasar 588013382734381143 spiralmania

[Budgieye]

older stars	younger stars	star-forming UV	OIII emissions	hydrogen emissions
1.024 8658198134352183470 posted by c_cld	0.98 spiral 587735664769827632 c_cld, from  Hubble	1.4 clumpy ring 588011123577586119 h.kohler/Tsering	1.14 pea? 587733412593468033 PhotoZ 0.7 in SDSS pea+star? AHZ100013x paulrogers	1.552 pink quasar 587726013998104664 starry nite
		2.73 lensed starburst 588290880028999911		2.380 blue quasar 587724197208784974 volare09
				3.295 blue quasar 587742189897973845 Tsering
				4.093 green quasar 587729408614334650 davidjamesjones
				5.414 red quasar 587727180613353723 starry nite farthest confirmed  on SDSS with spectrum see also z=5.685
				6.4 infrared quasar 588013383815791587 Mukund Vedapudi farthest seen on SDSS? no spectrum on SDSS

   

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There are many empty places in the higher redshifts because the light from ordinary galaxies is redshifted into infrared light,
which the SDSS camera cannot see. SDSS can see galaxies whose UV light is redshifted into visible light.

[Budgieye]

Sometimes a galaxy has characteristics of several types of galaxies.
So it isn't so easy.

Look at its spectral chart. For help see Zooite Guide to Spectra



Look at the "white pea".
587731680116867174

The colours in the images are in these areas on the chart

blue light                               4000-5500 Å

green light                               5500-7000 Å

red light                               7000-8500  Å

This "white pea" has a blue rise at 4000 Å   and a small blue OII peak, and a green OIII peak Normally, this would make a green pea. But the nucleus is active, making a Hα peak in the red. So, blue + green + red = white

Looking at some other examples

	This is a star-forming galaxy, making blue light. It would have a yellow nucleus (yellow is green+red) But the nucleus is also a blue pea, as seen by the OIII peak in the blue area of the spectrum.  So the nucleus is white  (white=blue+green+red) 0.032 588017115595145398 StephanieC
	0.079 This should be a blue compact galaxy, but it has an active nucleus, adding red to make a purple colour 587736547386261566 posted by c_cld
	This should be a green pea (OIII peak in green) , but it has an active nucleus (Hα peak in the red), so it is yellow. (green+red=yellow) 0.236 587738946670035133 liathro
	This is a green starburst, but it has an active nucleus (red), so it becomes yellow (green+red=yellow) 0.166 587739305298886782 posted by LizPeter
	This should be a magenta quasar (blue rise at 4000 + red Hα peak), but it is also a green pea, so it is white (green+blue+red=white) 0.326 quasar 587739406768144385 laithro
	This should be a blue quasar (blue rise at 40000), but it is also a red pea, so it is magenta (blue + red), also called purple, or sometimes pink 0.593 588009372300804174 liathro
	This is mostly a blue quasar, but it is also an ageing starburst, which adds a red colour to make magenta 0.752 587730774947594643 posted by c_cld

Then just when you think it starts to make sense, see
waveneys red spirals and blue ellipticals
 
For suggestions to changes to this chart, see Colours of Galaxies : Redshift chart suggestions on the Suggestions and Comments thread http://www.galaxyzooforum.org/index.php?topic=277143.0
 
Almost all the examples posted have a spectrum available.
Information on spectral charts is at Zooite Guide to Spectra
Do you want easy answers to a spectrum question? See Newbies, post your spectrum questions here or
Do you want exact answere to a spectrum question? See Tutorial bits on galaxy spectra


Other colour charts
liathro's colour survey (peas)
liathro's A little previously unknown objects gallery
OOTD Fri Jan 19 2009 Rick Nowells Markarian peas montage
Redshift Gallery: Quasars

Lists of objects (have I missed any?)
starry nite's OIII galaxy catalog
lianthro's OIII object categories
pea chart
Rick Nowell list of ccardamone's peas for the publication
Rick Nowells list of Markarians
Rick Nowells list of Wolf-Rayets

I can't take much credit for the chart: it is the work of thousands of Zooites.
Thank you to the Zooites who posted objects on the forum, all pretty and organized, so all I had to do was choose examples.
Thank you to the Zooites and astronomers who took time to share their knowledge,
and the moderators, and ZooKeepers, and SDSS for the images.

This chart was created when Galaxy Zoo 2 was using SDSS data.
It will not work for Hubble Zoo.

Here is a written chart


Different types of galaxies have different colours.
The colour of the galaxy changes with distance away (redshift) too.

Here is a table arranged by the type of object, and distance.


The types of objects are:
ellipticals - produce white light, from white stars
spirals - produce blue light from blue stars
compacts - produce ultraviolet light (UV) from young stars (star-forming galaxies)
OIII objects - produce emission lines from hot oxygen
active nuceus - produce emission lines from hot hydrogen

Galaxies that have several of these characteristics are discussed at the end.


                                                 redshift table for colours of galaxies

redshift	Million	ellipticals	spirals	star-forming	oxygen emission	hydrogen emission
z	light-year	white	blue	ultra-violet	OIII	Hα
0	0	white stars	blue stars	young stars	blue nebulae	green nebulae
.001	14	ellipticals	blue arms	blue compact	OIII regions	green emissions
0.01	137	ellipticals	blue spirals	blue compact	OIII regions	green nucleus
0.02	272	ellipticals	blue spirals	blue compact	blue peas	green nucleus
0.03	405	ellipticals	blue spirals	blue compact	blue peas	magenta nucleus
0.04	536	ellipticals	blue spirals	blue compact	blue peas	magenta nucleus
0.05	665	ellipticals	blue spirals	blue compact	purple peas	magenta nucleus
0.06	793	ellipticals	blue spirals	blue compact	purple peas	magenta nucleus
0.07	919	ellipticals	blue spirals	blue compact	purple peas	magenta nucleus
0.08	1040	ellipticals	blue spirals	blue compact	purple peas	magenta nucleus
0.09	1170	ellipticals	blue spirals	blue compact	purple peas	magenta nucleus
0.1	1290	yellow blobs	blue spirals	blue compact	white/green peas	magenta quasars
0.2	2410	yellow blobs	blue spirals	white compact	green peas	white quasars
0.3	3390	yellow blobs	blue smudge	green starburst	green peas	white quasars
0.4	4260	yellow blobs	green smudge	green starburst	yellow peas	blue quasars
0.5	5020	orange blobs	green smudge	yellow starburst	red peas	blue quasars
0.6	5690	red blobs	yellow smudge	red starburst	red peas	blue quasars
0.7	6290	red blobs	red smudge	magenta starbust	red peas	blue quasars
0.8	6830	red blobs	red smudge	magenta starburst	red peas	blue quasars
0.9	7300	red blobs	red smudge	magenta starburst	red peas	blue quasars
1.0	7730		smudge	white starburst		magenta quasars
2.0	10300			white starburst		blue quasars
3.0	11500			white starburst		blue quasars
4.0	12100					green quasars
5.0	12500					red quasars
6.0	12700	..........	..........	..........	..........	..........

1089	13770	Cosmic Microwave Background (CMB)
∞	13770	Big Bang

         
 
SDSS colours are used
color explanatation by laithro, starry nite and FermatsBrothers

Descriptions of unusual types of galaxies

[Edd]

Good heavens (excuse the unintentional pun?) - that's very comprehensive! Well done!