Optical Spectra: Special Plates

Extra Deep Plates

A few BOSS and eBOSS plates have been observed multiple times with different pluggings, or observed with the same plugging to greater depth (summed signal-to-noise squared) than typical:

BOSS plates Observed to ~3x median depth:

  • Plate 3683 MJD 55178, 55245
  • Plate 3879 MJD 55244
  • Plate 4083 MJD 55441, 55443
  • Plate 4202 MJD 55445
  • Plate 5141 MJD 55746
  • Plate 5399 MJD 55956

BOSS plate Observed to ~7x median depth split over 3 pluggings:

  • Plate 6037 MJD 56074, 56104, 56106

Multi-epoch Stripe 82 commissioning plates for LOWZ, CMASS, and QSO samples. These two plates cover the exact same targets on the same sky location, though they were observed at different hour-angles.

  • Plate 3615 MJDs 55179, 55208, 55445, 55856, 56219, 56544
  • Plate 3647 MJDs 55181, 55241, 55476, 55827, 55945, 56219, 56568, 56596

Deep spectra of quasar targets identified by variability:
One field from a BOSS ancillary program was observed multiple times to obtain higher quality spectra.

  • Plate 6782 MJDs 56273, 56572, 56576, 56602

Repeat Observations of a standard eBOSS field:
These two plates cover the exact same targets on the same sky location:

  • Plate 7691 MJDs 57040, 57360, 58124, 58487
  • Plate 10000 MJDs 57346, 57716, 58141, 58462, 58514

Deep Spectra of an ELG sample from eBOSS:

  • Plate 9414 MJDs 58083, 58153, 58155, 58162
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Ancillary Program Plates

Complete list of ancillary programs within BOSS  

Most of these were in the last year of eBOSS operations, but earlier special plates include:

  • Emission Line Galaxies / Luminous Blue Galaxies: plates 5017, 5018, 6931, 6932, 6933, 7455, 7456, 7457, 7240 - 7245
  • QSO variability selection in Stripe 82: plates 5141 - 5147
  • Mostly sky fibers for sky subtraction tests: plate 5745
  • LRG test plates: 6373 - 6398
  • TDSS / SPIDERS  test plates: 6369, 6783
  • QSO plates with same targets but different plate drilling:
    • 6370 (with xy offsets: optimize S/N at 4000 A)
    • 6780 (without xy offsets: optimize S/N at 5400 A)
  • Other QSO test plates: 6780, 6781, 6782
  • 5141 - 5147: Stripe 82 QSO variability selection study
  • XMMXLL: 7235 - 7238
  • Orion Taurus: 7257, 7259, 7260, 7261, 7272
  • DEEP_QSO: 7334, 7336, 7337
  • Reverberation mapping plates: 7338, 7339, 7340
  • Lofar plates: 7562 - 7565
  • SEGUE GES: 7253 - 7256, 7258, 7330 - 7333, 7451-7457
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eFEDS Plates

7 plates within the eROSITA Final Equatorial-Depth Survey (eFEDS) region were observed in Spring 2020 as part of the SPIDERS program. These plates were first released in DR17, with more details on their observing conditions and target selection available in the DR17 data release paper Abdurro’uf et al. (2022). The DR17 eFEDS plates are also available in the DR17 Science Archive Webapp using the following link.

  • eFEDS plates 12525, 12527, 12531, 12533, 12544, 12545, 12547
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Notes

  • In all cases, the plates are processed identially to standard survey plates and all targets treated the same.
  • See the BOSS_TARGET1, ANCILLARY_TARGET1, and ANCILLARY_TARGET2 bits for details of which targets come from which programs and details about those programs.
  • Also note that there are many other ancillary program targets interleaved with the rest of the survey on standard BOSS plates as identified by their ANCILLARY_TARGET1 and ANCILLARY_TARGET2 bits. The above plates simply point out a few cases where most of a plate is dedicated to ancillary programs.
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