I have performed a color-color and colour-magnitude plot of various sources detected in an LMC image (JWST NIRCAM F200W, F150W and F115W filters). I then also queried SIMBAD to collect relevant photometric data (UBVRIJHKLMN system) on various stars of different spectral types. Moving between the 2 different filter systems was done via an initial estimate through the effective wavelength midpoints for which UBVRIJHKLMN system filters to use for each JWST filter, and then a regression through sets of standard stars to move as accurately as possible between the two filter systems. Plotting both sets of data creates the graph below - there is a clear trend for the SIMBAD data, but the LMC data simply doesn't follow it in the slightest. Any ideas of what these LMC objects might be?


enter image description here


enter image description here


O = red

B = blue

A = orange

F = yellow

G = pink

K = purple

M = green

LMC objects = black

files on MAST:

f200w file = jw01476001011_02101_00001_nrca4_i2d.fits

f150w file = jw01476001007_02101_00001_nrca4_i2d.fits

f115w file = jw01476001005_02101_00001_nrca4_i2d.fits

  • 1
    $\begingroup$ How did you choose the"various sources"? How bright are they and where are they in a colour-magnitude diagram. Are the "various stars of different spectral types" main sequence stars with no extinction? $\endgroup$
    – ProfRob
    Commented Aug 26, 2023 at 19:25
  • $\begingroup$ The sources are the brightest sources above a set sensitivity for astropy's DAOFIND function. I have added a colour-magnitude plot above. The stars from SIMBAD are not all necessarily main-sequence as each type has been searched for with set radii around different points in the sky in order to find places where each type was lucrative (to get enough data points). In other words, their other properties are random bar their spectral types. I have not accounted for extinction here and, as far as I'm aware, neither does the SIMBAD database. $\endgroup$
    – KBo
    Commented Aug 29, 2023 at 12:55


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