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 has conducted a series of collaboration-internal “open fiber proposal” calls. DR20 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:
- more extensive surveying of AGNs and X-ray sources across the sky;
- broader stellar physics, in particular binary star physics, across the color-magnitude diagram (CMD);
- 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 Name | Description | Instrument | Available 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 | v2020_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 |
| openfibertargets_mwm_als_boss | Targets from the ALS catalog (Pantaleoni-Gonzáles et al. 2021), a catalog of OB stars, that are not part of the OB(A) core carton. | BOSS | 5840 |
| openfibertargets_mwm_asassn_eb_apogee | Selection of eclipsing binaries (Rowan et al. 2022, Christy et al. 2023, Jayasinghe et al. 2021) | APOGEE | 45343 |
| openfibertargets_mwm_bhc_gdr4_apogee | Gaia sources that are a poor fit to a single star model but are not part of the single star catalog, that have large RV variation and are metal-poor. | APOGEE | 3004 |
| openfibertargets_mwm_bhc_gdr4_boss | Gaia sources that are a poor fit to a single star model but are not part of the single star catalog, that have large RV variation and are metal-poor. | BOSS | 3004 |
| openfibertargets_mwm_compactbinaries_boss | Crossmatch of Gaia DR3 with the various X-ray catalogs, using Rodriguez (2024) to select accreting compact object candidates from Galactic X-ray sources. | BOSS | 418 |
| openfibertargets_mwm_ellipsoidal_bh_ns_candidates_boss | Subset of gaia_dr3.vari_compact_companion catalog are provided in Gomel et al. (2022) | BOSS | 6306 |
| openfibertargets_mwm_lvm_als_apogee | OB stars in the ALS II MW catalog of Pantealoni-Gonzalez et al. (2021) | APOGEE | 15560 |
| openfibertargets_mwm_lvm_als_boss | OB stars in the ALS II MW catalog of Pantealoni-Gonzalez et al. (2021) | BOSS | 15560 |
| openfibertargets_mwm_lvm_lmc_apogee | LMC OB stars selected using Maiz-Apellaniz et al. (2023) method | APOGEE | 54550 |
| openfibertargets_mwm_lvm_lmc_boss | LMC OB stars selected using Maiz-Apellaniz et al. (2023) method | BOSS | 54550 |
| openfibertargets_mwm_lvm_smc_boss | SMC OB stars selected using Maiz-Apellaniz et al. (2023) method | BOSS | 14331 |
| openfibertargets_mwm_stripped_stars_plane_boss | A color corrected sample of stripped star candidates at low Galactic latitudes | BOSS | 6799 |
| openfibertargets_mwm_subgiant_nataf24_apogee | all subgiants from the catalog presented in Nataf et al. (2024) with H <= 11 | APOGEE | 108690 |
| openfibertargets_mwm_subgiants_apogee | Selection of subgiants from Andrae et al (2023) | APOGEE | 92657 |
| openfibertargets_mwm_tess_ellipsoidals_repeat_apogee | A repeat epoch of all targets from open fibre proposal openfibertargets_nov2020_22 | APOGEE | 33513 |
| openfibertargets_mwm_tessperiodic_apogee | Periodic variable stars from TESS within 250 pc with periods <10 days | APOGEE | 112526 |
| openfibertargets_mwm_tessperiodic_boss | Periodic variable stars from TESS within 250 pc with periods <10 days | BOSS | 112526 |
| openfibertargets_mwm_vmr_apogee | Selection of red giants from Andrae et al (2023) | APOGEE | 33340 |
| openfibertargets_mwm_vmr_boss | Selection of red giants from Andrae et al (2023) | BOSS | 48763 |
| openfibertargets_mwm_ztf_scope_apogee | Selection of periodic stars from ZTF as part of ZTF SCoPe project | APOGEE | 29323 |
| openfibertargets_mwm_ztf_scope_boss | Selection of periodic stars from ZTF as part of ZTF SCoPe project | BOSS | 278209 |
| openfibertargets_mwm_sphx_apogee | IR-bright stars in dusty regions of MW that are planned for follow-up with SPHEREx (Ashby et al., 2023) | APOGEE | 525562 |
| openfibertargets_mwm_sphx_boss | IR-bright stars in dusty regions of MW that are planned for follow-up with SPHEREx (Ashby et al., 2023) | BOSS | 525562 |
| openfibertargets_mwm_lvm_smc_apogee | SMC OB stars selected using Maiz-Apellaniz et al. (2023) method | APOGEE | 14331 |
| openfibertargets_bhm_racsradio_boss | BOSS spectroscopy of optically bright counterparts of bright 888MHz radio sources identified by in the ASKAP/RACS-low survey (Hale et al. 2021) | BOSS | 149989 |
| openfibertargets_bhm_varagn_boss | Selection of AGNs using variability from ZTF (Shu et al. 2019) | BOSS | 6966 |
| openfibertargets_bhm_morexray_boss | Selection of X-ray sources from ExSeSS (Swift) and 4XMM-DR13 | BOSS | 103105 |
| openfibertargets_bhm_hightderates_psb_boss | all PSB galaxies identified by the machine learning algorithm in French & Zabludoff (2018) | BOSS | 8934 |
| openfibertargets_bhm_hightderates_qbs_boss | all QSB galaxies identified by the machine learning algorithm in French & Zabludoff (2018) | BOSS | 29659 |
| openfibertargets_bhm_quaia_boss | Selection of quasars in the Quaia (the Gaia–unWISE Quasar) Catalog | BOSS | 999906 |
| openfibertargets_mwm_gaia_var_cvs_boss | Selection of sources from the Gaia variability catalog that are classified as CV | BOSS | 7306 |
| openfibertargets_bhm_lofarradio_boss | Selection of optically bright counterparts of low-frequency radio sources identified by LOFAR Two Metre Sky Survey (LOTSS) | BOSS | 216081 |
| openfibertargets_mwm_cvcandidates_boss | Selection of candidate cataclysmic transients, typically identified from transient alerts | BOSS | 10618 |
| openfibertargets_mwm_ztf_lomb_apogee | Selection of periodic stars from ZTF using Lomb-Scargle periodogram | APOGEE | 100976 |
| openfibertargets_mwm_ztf_lomb_boss | Selection of periodic stars from ZTF using Lomb-Scargle periodogram | BOSS | 128291 |
| openfibertargets_mwm_hypervelocity_stars_boss | Selection of stars with tangential velocities of > 600 km/s | BOSS | 5268 |
| openfibertargets_mwm_snc_further_ext_apogee_bright | Selection of stars with distances between 100 and 500 pc | APOGEE | 30635 |
| openfibertargets_mwm_snc_further_ext_boss | Selection of stars with distances between 100 and 500 pc | BOSS | 8872858 |
| openfibertargets_mwm_snc_further_ext_apogee_dark | Selection of stars with distances between 100 and 500 pc | APOGEE | 30635 |
| openfibertargets_mwm_more_ob_boss | Selection of stars with absolute magnitude in the K band -0.6 < M_K < 0. and colors consistent with being (reddened) massive stars | BOSS | 450002 |
| openfibertargets_bhm_agn_asas_sn_2mass_boss | SDSS V Spectroscopic Studies of Variability Selected AGN from ASAS-SN, first observations | BOSS | 1092 |
| openfibertargets_bhm_agn_asas_sn_sdssspec_boss | SDSS V Spectroscopic Studies of Variability Selected AGN from ASAS-SN, reobserving | BOSS | 37 |
| openfibertargets_bhm_blazars_boss | SDSS V Spectroscopic Study of Blazars | BOSS | 4194 |
| openfibertargets_bhm_broadbcds_boss | Hunting for local ‘Little Red Dots’ with BOSS spectroscopy | BOSS | 3064 |
| openfibertargets_bhm_iragn_boss | BOSS spectroscopy of dust-reddened WISE selected AGN in the eROSITA footprint | BOSS | 116577 |
| openfibertargets_mwm_halo_gaiasgr_boss | Selection of stars in Sagittarius streams | BOSS | 45147 |
| openfibertargets_mwm_halo_gaiastreams_boss | Selection of stars in stellar streams | BOSS | 4379 |
| openfibertargets_mwm_pgir_lpvs_apogee | APOGEE spectroscopy of IR-selected long period variables | APOGEE | 97272 |
| openfibertargets_mwm_protoclusters_apogee | Selection of stars in young protoclusters | APOGEE | 52929 |
| openfibertargets_mwm_protoclusters_boss | Selection of stars in young protoclusters | BOSS | 52929 |
| openfibertargets_mwm_rvscnn24_apogee | Gaia-RVS selected Main sequence Turn-off & Sub-giant stars | APOGEE | 95155 |
| openfibertargets_mwm_rvscnn24_metal_poor_giants_apogee | Gaia-RVS selected metal-poor giants | APOGEE | 7667 |
| openfibertargets_mwm_rvscnn24_nearby_dwarfs_apogee | Gaia-RVS selected nearby dwarf stars | APOGEE | 16559 |
| openfibertargets_bhm_clu_boss | Galaxies in the Census of the Local Universe (CLU) | BOSS | 25834 |
| openfibertargets_mwm_mdwarfs_plato_apogee | PLATO M-dwarf targets | APOGEE | 11330 |
| openfibertargets_mwm_halo_bhb_boss | Halo Blue horizontal-branch stars | BOSS | 20402 |
| openfibertargets_mwm_halo_empxp_boss | Halo extremely metal poor stars | BOSS | 4302 |
| openfibertargets_mwm_nearbyocmg_boss | Low Mass Members and Escapee Candidates of Nearby Open Clusters and Moving Groups | BOSS | 84519 |
| openfibertargets_mwm_spyglassysos_apogee | YSOs in the SPYGLASS catalog | APOGEE | 99275 |
| openfibertargets_mwm_spyglassysos_boss | YSOs in the SPYGLASS catalog | BOSS | 56750 |
| openfibertargets_mwm_strippedstars_boss | Selection of compact stripped stars | BOSS | 91957 |
| openfibertargets_bhm_iragn2_boss | BOSS spectroscopy of dust-reddened WISE selected AGN in the northern sky | BOSS | 570054 |
| openfibertargets_bhm_broadbcds2_boss | JWST ‘Little Red Dots’ | BOSS | 1006 |