Are the bright dots in this image individual stars? I saw this picture of M51 (Whirlpool galaxy) and noticed many, many bright dots around and in the galaxy. I have freehand-circled a few as examples. Are these individual stars (probably supergiants) in the Whirlpool Galaxy, or are they clusters, stars in the Milky Way, or something else?

Source: ESA/Hubble
A query to the Gaia Archive within 6 arc min of target name M51 finds 20 sources with phot_g_mean_mag &lt;= 17.
Aladin Lite helps to locate them visually.
Five are circled in the lower half of the image in question:




Gaia source_id
ra °
dec °
parallax (mas)
magg




1551894661845524736
202.4034
47.1522
8.854 ± 0.017
14.3


1551988532650838016
202.4205
47.1790
2.387 ± 0.041
16.4


1551988670089792256
202.4236
47.1979
0.632 ± 0.025
15.1


1551988425277200640
202.4323
47.1537
0.813 ± 0.025
15.2


1551988567010595840
202.4417
47.1800
1.536 ± 0.012
13.3




These parallaxes indicate distances between 113 and 1600 parsecs, well within the Milky Way.
Of the three sources circled in the upper half, two seem to be listed in Gaia EDR3 but do not have good parallaxes there.
Aladin Lite shows SIMBAD matches near all three in
Hwang and Lee 2008, a catalog of 2200 star clusters in M51.




HL2008 id
ra °
dec °
magV
Gaia source_id




89770
202.494
47.216
20.0
1551988944968489984


13162
202.505
47.154
21.1
--


28066
202.531
47.167
19.8
1551987909882986368