Leo A missing from SGA?

[rongpu]

It appears that Leo A is missing from the SGA (or at least it has no large galaxy mask that prevents targeting inside the galaxy). https://www.legacysurvey.org/viewer?ra=149.85880062471412&dec=30.747339012022397&zoom=14&layer=ls-dr9&masks-dr9

[rongpu]

I just noticed that Leo I also doesn't haven't any masking (thus the many ELG and other targets in it): https://www.legacysurvey.org/viewer?ra=152.1157&dec=12.3088&layer=ls-dr9&zoom=13&masks-dr9&targets-dr9-main-dark

[moustakas]

This was a bug that I identified after we had launched DR9, unfortunately, and it affects a total of 52 galaxies, several of them local-group dwarfs like Leo A and Leo I (but not all of them in the DESI footprint). The bug has been fixed in the public-release version of the SGA, but it does mean that we'll need to include these objects (along with any other large shredded galaxy not included in the SGA due to incompleteness of the parent Hyperleda catalog) in a post-facto veto mask.

Briefly, the issue is that we had come up with a list of galaxies whose ellipse geometry we wanted to "veto"-- https://github.com/moustakas/legacyhalos/blob/main/py/legacyhalos/SGA.py#L49-L134

However, when assembling the SGA "ellipse" catalog these objects were handled in the wrong part of the code, and so they were flagged as 'preburned=Falsetheirref_cat` column was never populated, which means that the DR9 pipeline ignored them-- https://github.com/legacysurvey/legacypipe/blob/main/py/legacypipe/reference.py#L487-L488

You can identify the affected galaxies thusly:

import numpy as np
from astropy.table import Table
ee = Table.read('/global/cfs/cdirs/cosmo/data/legacysurvey/dr9/masking/SGA-ellipse-v3.0.kd.fits')
nn = Table.read('/global/cfs/cdirs/cosmo/staging/largegalaxies/v3.0/SGA-ellipse-v3.0.fits')
old = ee[ee['SGA_ID'] > -1]
new = nn[nn['SGA_ID'] > -1]
old = old[np.argsort(old['SGA_ID'])]
new = new[np.argsort(new['SGA_ID'])]
ww = (old['REF_CAT'] == '') * (new['REF_CAT'] == 'L3')
new[ww]['SGA_ID', 'GALAXY', 'RA', 'DEC']
<Table length=52>
 SGA_ID         GALAXY                 RA                 DEC
 int64          str29               float64             float64
------- ---------------------- ------------------ -------------------
   5855              PGC091171 181.49243818670325  39.859543546460685
  94522             PGC2034992 215.14625995464263  33.580232392841516
 153246              PGC061640  273.7349309270346   61.30410270178651
 172039              PGC145889  58.89315027767511 -7.5914781396613185
 256985              PGC090808 119.01849197178315   34.35388129889917
 364762              PGC090861 129.54683422632405  45.883263026195905
 403602             PGC2665094  269.5057613959715   64.15919273494667
 434884               UGC04788 137.09625758817964  59.074544240602634
 495017             PGC2385881 141.33600974513453    50.9649259754167
 508767              PGC213966 184.26221341525493  49.515040688660285
 613162             PGC1090829 182.94564293685565 -2.4806775266509486
 619373             ESO349-031 2.0598038209663847  -34.57900378060832
 622822              PGC020336 107.77437703296359   49.89728132963495
 649301 2MASXJ13161816+0925305 199.07576605121739   9.425214247465137
 680702               UGC10736 257.01988784791763   69.46458763898741
 695757             PGC2123520 227.57879405155666   38.31001154839722
 698775              PGC437802  95.38201139382475   -52.8430962054826
 706828             PGC1029274 215.14239667935368  -6.746308950817718
 711393              PGC090944 146.89892246930768  23.906750928512782
 803877             PGC2046017 110.95591190564288   34.23762042225427
 808605               UGC04363 126.26357926136917   74.43332621431136
 814629             PGC2371341  142.3386591951591   50.37982500327484
 859676             PGC2631024 175.64229995576568   62.12511544831738
 879500               UGC03974   115.481690559151  16.802349773910837
 885744              PGC147988  86.88897670939045  -48.74855879277899
 957532              PGC022276   119.242365877934  63.678652722301926
 967499               UGC07599 187.11750378061328   37.23378729112367
 971408               UGC10111  239.5548691915027   13.16881711661988
 972716               UGC10061  237.8126391900445  16.329069007330837
1013917              PGC006108  24.78807532908279 -10.503771030191944
1061937        UGC08308  198.3447737566479   46.32153141964399
1076902       PGC061380 271.29745387413567   34.70467963250459
1143428        UGC03998 116.33751820882024  56.152202572796355
1164958      PGC1783580  241.8439227232705   26.64261938412157
1165448        UGC09630  221.8679666786117   52.82430738062724
1192615      PGC2022273 225.07750232437104   33.06703327766959
1213481       PGC086661 236.43271664998986  17.314812871090357
1278701      PGC3288397 170.38567343620335 -0.5276015862580563
1280924      PGC2283901 119.92682912533307  46.597178516337735
1367043      PGC2042481 255.36070077196013   34.01320143726745
1402356      PGC1036933  348.5439928116697  -6.085830228518373
1423281       PGC091013 156.73460829940683    70.5594988118539
2000021           LeoII 168.36244218690902  22.152672343278812
2000022            LeoI 152.11102923115868  12.301452551673346
2000051            LGS3 15.978923905269566  21.881433955324994
2000052     AndromedaVI 357.94361907879767  24.583379417302584
2000054 AndromedaXXVIII  338.1750152088672  31.218499090978415
2000056         Phoenix  27.77950727211065 -44.446110564110526
2000058           Cetus   6.54812996979702  -11.04412694332917
2000062            LeoA  149.8577508713963  30.748408531487847
2000065          Tucana 340.45998947194573  -64.42081654942292
2000085          DDO125   186.922381806541   43.49521352254848

About half of these have a diameter larger than an arcmin:

<Table length=27>
 SGA_ID      GALAXY             RA                 DEC            DIAM
 int64       str29           float64             float64        float32
------- --------------- ------------------ ------------------- ---------
 364762       PGC090861 129.54683422632405  45.883263026195905  1.020728
 434884        UGC04788 137.09625758817964  59.074544240602634 1.4351919
 619373      ESO349-031 2.0598038209663847  -34.57900378060832       1.5
 622822       PGC020336 107.77437703296359   49.89728132963495 1.0044075
 680702        UGC10736 257.01988784791763   69.46458763898741 3.7836413
 711393       PGC090944 146.89892246930768  23.906750928512782 1.1532142
 808605        UGC04363 126.26357926136917   74.43332621431136     1.875
 879500        UGC03974   115.481690559151  16.802349773910837  5.431378
 967499        UGC07599 187.11750378061328   37.23378729112367 2.3276088
 971408        UGC10111  239.5548691915027   13.16881711661988 2.0366201
 972716        UGC10061  237.8126391900445  16.329069007330837 2.3276088
1013917       PGC006108  24.78807532908279 -10.503771030191944 1.6745958
1061937        UGC08308  198.3447737566479   46.32153141964399 1.2557696
1076902       PGC061380 271.29745387413567   34.70467963250459 1.1373916
1143428        UGC03998 116.33751820882024  56.152202572796355 1.3517926
1165448        UGC09630  221.8679666786117   52.82430738062724 1.2020153
1213481       PGC086661 236.43271664998986  17.314812871090357 1.8446333
2000021           LeoII 168.36244218690902  22.152672343278812      13.0
2000022            LeoI 152.11102923115868  12.301452551673346      17.0
2000051            LGS3 15.978923905269566  21.881433955324994      5.25
2000052     AndromedaVI 357.94361907879767  24.583379417302584      11.5
2000054 AndromedaXXVIII  338.1750152088672  31.218499090978415    4.1625
2000056         Phoenix  27.77950727211065 -44.446110564110526       9.4
2000058           Cetus   6.54812996979702  -11.04412694332917 6.2504315
2000062            LeoA  149.8577508713963  30.748408531487847  5.753207
2000065          Tucana 340.45998947194573  -64.42081654942292       5.5
2000085          DDO125   186.922381806541   43.49521352254848 6.2400002

[moustakas]

No action on this ticket for either the SGA or legacypipe. We need to just update the documentation-- https://github.com/legacysurvey/legacysurvey/issues/170#issuecomment-1609652044