Open Fiber Programs

The SDSS-V focal plane fiber-positioning hardware and survey strategy were designed around the core science cases, whose target densities — and relative infrared vs optical needs —  vary dramatically across the sky, from Baade’s window to high-latitudes. This inevitably leaves unallocated (or “open”) fibers.

In response to this SDSS-V opened a (series of) collaboration-internal “open fiber proposal” call. DR19 includes the 30 target category proposals that resulted from the first call in November 2020. Boundary conditions for these proposals were that:

  • the science goals — complementing core science — could be reached with single 15~minute exposures using either the APOGEE (infrared) or BOSS (optical) spectrographs;
  • the targeting information was freely available to all SDSS-V members, and a target selection function could be specified.

Much of the proposed science fell into three broad categories:

  1. more extensive surveying of AGNs and X-ray sources across the sky;
  2. broader stellar physics, in particular binary star physics, across the color-magnitude diagram (CMD);
  3. studying the Milky Way’s stellar halo and metal-poor population, which (intentionally) had not been a focus of the Galactic Genesis program.

These programs were reviewed by an consortium-internal independent panel in early 2021, and their target categories are listed in the table below, including the number of targets submitted to the program. 

Carton NameDescriptionInstrumentAvailable Targets1
openfibertargets_nov2020_3 Selection of eclipsing binaries (EA and EB) identified with ASAS-SN BOSS 34689
openfibertargets_nov2020_5 Selection of extremely metal poor ([Fe/H]<-3) stellar candidates identified on the basis of SkyMapper photometry, following the selection criteria outlined by Da Costa et al. (2019) BOSS 39099
openfibertargets_nov2020_6a Selection of stars in galactic halo on the basis of photometry from SkyMapper Southern Survey → Blue horizontal branch stars using criteria from Wang et al. 2020 BOSS 50611
openfibertargets_nov2020_6b Selection of stars in galactic halo on the basis of photometry from SkyMapper Southern Survey → Metal poor RGB stars using criteria from Huang et al. 2019 BOSS 340436
openfibertargets_nov2020_6c Selection of stars in galactic halo on the basis of photometry from SkyMapper Southern Survey: Metal poor dwarf stars BOSS 890043
openfibertargets_nov2020_8 Selection of stars in nearby young moving groups within 3 kpc from Kounkel et al. 2020, limited to sourced with ages log t>7.5 [yr] BOSS/APOGEE 704638
openfibertargets_nov2020_9 Selection of F stars performed using infrared colors BOSS/APOGEE 1197354
openfibertargets_nov2020_10 Selection of chemically anomalous (Na-rich, Al-rich, K-rich, P-rich, Si-rich, N-rich, s-process-rich, and CN-strong) stars previously observed by APOGEE to obtain a second radial velocity (RV) epoch to monitor RV variability BOSS/APOGEE 917
openfibertargets_nov2020_11 Selection of quasars observed during SDSS-I and -II which had only a single epoch to changes in emission lines and absorption line troughs over timescales of years to decades BOSS 39684
openfibertargets_nov2020_12 Selection of spectroscopic binaries from Price-Whelan et al. 2020 and Kounkel et al. 2021 identified in APOGEE spectra to receive an additional RV epoch BOSS/APOGEE 33577
openfibertargets_nov2020_14 Selection of unresolved main sequence + white dwarf binaries based on their location on the Gaia Color Magnitude Diagram (CMD) BOSS 10798
openfibertargets_nov2020_15 Selection of members of open clusters from Cantat-Gaudin et al. 2019 BOSS/APOGEE 177185
openfibertargets_nov2020_17 Selection of pre-main sequence star candidates within 500 pc from Zari et al. 2018 BOSS 32891
openfibertargets_nov2020_18 Selection of hard X-ray emitting sources (primarily AGNs) from XMM-Newton and Swift serendipitous surveys BOSS 10012
openfibertargets_nov2020_19a Selection of targets that received 2-min cadence monitoring by TESS in its first two years → Sources loaded into the database based on Gaia DR2 IDs BOSS/APOGEE 224773
openfibertargets_nov2020_19b Selection of targets that received 2-min cadence monitoring by TESS in its first two years →Sources loaded into the database based on Legacy Survey DR8 IDs BOSS/APOGEE 1605
openfibertargets_nov2020_19c Selection of targets that received 2-min cadence monitoring by TESS in its first two years →Sources loaded into the database based on PanSTARRS IDs BOSS/APOGEE 1615
openfibertargets_nov2020_22 Selection of binaries undergoing ellipsoidal variability identified in TESS full frame images from Green et al. (2023) APOGEE 28408
openfibertargets_nov2020_24 Selection of K/M metal-rich dwarfs in the distance range of 250pc<D<500pc identified based on their location on the Gaia Color Magnitude Diagram (CMD) BOSS 1323442
openfibertargets_nov2020_25 Selection of high proper motion K/M halo metal-poor stars up to 1 kpc identified based on their location on the Gaia Color Magnitude Diagram (CMD) BOSS/APOGEE 293741
openfibertargets_nov2020_26 Selection of quasars monitored in SDSS-I and II as a part of ultraviolet Broad Absorption Line (BAL) Quasar Variability Survey (Gibson et al. 2009) to receive an additional epoch of observations to monitor wind evolution BOSS 2105
openfibertargets_nov2020_27 Selection of bright quasar candidates with quasar-like Gaia and unWISE photometry, supplemented with multi-epoch variability observed by DES, excluding regions of high confusion BOSS 814963
openfibertargets_nov2020_28a Selection of halo stars → RR Lyrae sources selected based on the position on the Gaia Color Magnitude Diagram (CMD) that demonstrate variability in Gaia passbands BOSS 73627
openfibertargets_nov2020_28b Selection of halo stars → K giants outside of Galactic plane (|b|>10 deg) selected based on a combination of Gaia and 2MASS colors BOSS 49900
openfibertargets_nov2020_28c Selection of halo stars → Blue Horizontal Branch stars selected based on Gaia and GALEX colors BOSS 51234
openfibertargets_nov2020_29 Selection of extra-tidal stars associated with globular clusters BOSS/APOGEE 107688
openfibertargets_nov2020_30 Selection of bright sources in JWST North Ecliptic Pole Time-Domain Field BOSS 237
openfibertargets_nov2020_31 Selection of sources spectra of which previously have been obtained with RAVE to enable cross-calibration APOGEE 62275
openfibertargets_nov2020_32 Selection of resolved main sequence + white dwarf binaries from El-Badry & Rix (2018) BOSS/APOGEE 34230
openfibertargets_nov2020_33 Selection of candidate AGN, QSOs, and Blazars identified based on their ZTF variability flagged by ALeRCE light curve classifier (Sanchez-Saez et al 2020) BOSS 22250
openfibertargets_nov2020_34a Selection of sources across Gaia CMD to provide equal representation of all areas of parameter space → Nonvariable stars BOSS 8701166
openfibertargets_nov2020_34b Selection of sources across Gaia CMD to provide equal representation of all areas of parameter space → Variable stars BOSS 643546
openfibertargets_nov2020_35a Selection of metal-poor halo stars → Best & Brightest sources following Schlaufman & Casey (2014) using 2MASS and WISE photometry, regression trained on known metal-poor stars BOSS 345721
openfibertargets_nov2020_35b Selection of metal-poor halo stars → Sources selected using Skymapper DR1 photometric metallicities from Casagrande et al. 2019, limited to [Fe/H]<-1.7 BOSS 52696
openfibertargets_nov2020_35c Selection of metal-poor halo stars → Sources selected using metallicities derived from SAGE Survey (Zheng et al. 2018), limited to [Fe/H]<-2 BOSS 7521
openfibertargets_nov2020_46 Selection of sources which had at least 2 epochs of observations with LAMOST to provide another radial velocity (RV) epoch BOSS 663835
openfibertargets_nov2020_47a Selection of sources in the Large and Small Magellanic Clouds (LMC and SMC) based on Gaia photometry and astrometry → RGB stars BOSS 278987
openfibertargets_nov2020_47b
Selection of sources in the Large and Small Magellanic Clouds (LMC and SMC) based on Gaia photometry and astrometry → AGB stars
APOGEE 27731
openfibertargets_nov2020_47c Selection of sources in the Large and Small Magellanic Clouds (LMC and SMC) based on Gaia photometry and astrometry → Massive stars to be observed with BOSS BOSS 1000
openfibertargets_nov2020_47d Selection of sources in the Large and Small Magellanic Clouds (LMC and SMC) based on Gaia photometry and astrometry → Massive stars to be observed with APOGEE APOGEE 1000
openfibertargets_nov2020_47e Selection of sources in the Large and Small Magellanic Clouds (LMC and SMC) based on Gaia photometry and astrometry → Symbiotic stars APOGEE 24
openfibertargets_nov2020_1000 Selection of members of globular clusters from Baumgardt et al. (2018) and Harris (1996) BOSS/APOGEE 102172
openfibertargets_nov2020_1001a Selection of wide binaries identified by El Badry & Rix (2018) → All sources BOSS/APOGEE 81303
openfibertargets_nov2020_1001b Selection of wide binaries identified by El Badry & Rix (2018) → Subset of higher probability sources BOSS 10545
1Available targets is the number of targets that satisfy the carton selection function in the targeting database. The number of targets ultimately observed for each carton will be smaller than this value.

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