The Solar Neighborhood targets a volume-limited sample of stars with the goals of cataloging low-luminosity stellar populations. These will be the brightest of each type, and we will be able to determine accurate stellar parameters from the combination of spectroscopy, photometry, and parallaxes. In addition, we will be able to get very good constraints on binarity from the combination of radial velocity (RV) spectroscopy and Gaia astrometry. The most complete census will be within 100 pc, where we expect to observe >60% of stars by the end of SDSS-V. However, few stars within 100 pc have spectral types earlier than K; therefore, a sample of G-type stars and earlier within 250 pc will also be targeted to enable a reliable match to higher luminosity populations.
The Gaia DR2 parallaxes are noticeably less accurate in highly crowded regions. Therefore, stars close to the Galactic plane and the Magellanic Clouds have an additional quality cut on astrometric noise imposed.
Cartons
mwm_snc_100pc
This carton is the 100 pc sample observed during the plate era from targeting plan 0.1.0. In DR19, all cartons in this program also belong to the alternate name mwm_snc.
The selection criteria utilized astrometric information from Gaia DR2 and photometry from both Gaia DR2 or 2MASS. Dense regions were defined with the Galactic longitude b and Galactic latitude l in degrees as follows:
- Galactic Plane:
- l<=180 and b<-0.139*l + 25 and b>0.139*l-25 OR
- l>180 and b>-0.139*l + 25 and b <0.139*l – 25
- SMC: sqrt( (l-303.2)2 + 2*(b+44.4)2 ) < 5
- LMC: sqrt( (l-280.3)2 + 2*(b+33.0)2 ) < 8
Selection Criteria
- parallax-parallax_error > 10 mas
- if in dense region, astrometric_excess_noise < 2
mwm_snc_100pc_apogee
This carton is the FPS era 100 pc sample observed with the APOGEE instrument under targeting plan 0.5.0. In addition to the selection criteria of mwm_snc_100pc, this carton required H < 11.
In targeting v1 this cartons target selection was updated to Gaia DR3.
mwm_snc_100pc_boss
This carton is the FPS era 100 pc sample observed with the BOSS instrument under targeting plan 0.5.0. In addition to the selection criteria of mwm_snc_100pc, this carton also required G-band detection in Gaia.
In targeting v1 this carton was updated for Gaia DR3 and added a G > 10 magnitude cut.
In targeting generations v1.0.5 and v1.0.5-boss-only there were additional selection criteria added:
- gal_cut is the previously used galactic l and b cuts.
- parallax > 0
- parallax – parallax_error > 10
- ((astrometric_excess_noise < 2) AND (l >= 20) AND (l <= 340) AND gal_cut) OR ((astrometric_excess_noise < 2) AND (ruwe < 1.2) AND ((1 + 0.015 * (phot_bp_mean_mag – phot_rp_mean_mag)^2) < phot_bp_rp_excess_factor) AND (phot_bp_rp_excess_factor < (1.3 + 0.06 * (phot_bp_mean_mag – phot_rp_mean_mag)^2)) AND ((l < 20) OR (l > 340)) AND gal_cut) OR NOT gal_cut)
There are two associated identical carton mwm_snc_100pc_boss_single and mwm_snc_100pc_bright_boss_single.
mwm_snc_100pc_low_lum_boss_single
This is a subcarton of mwm_snc_100pc_boss with additional cuts on astrometric noise and G Mag. This carton is specifically designed to prioritize the low luminosity stars in the 100 pc sample.
- Original selection from mwm_snc_100pc_boss
- G + 5 * log10(0.001 * parallax) + 5 > 16
mwm_snc_250pc
This carton is the 250 pc sample observed during the plate era from targeting plan 0.1.0. To observe stars of type G and earlier, we limit the absolute magnitude MG< 6.
Selection Criteria
- parallax – parallax_error > 4
- if in dense region, astrometric_excess_noise < 2
- G+5 * log10(parallax / 1000) + 5 < 6
mwm_snc_250pc_apogee
This carton is the FPS era 250 pc sample observed with the APOGEE instrument under targeting plan 0.5.0. In addition to the selection criteria of mwm_snc_250pc, this carton required H < 11.
mwm_snc_250pc_boss
This carton is the FPS era 250 pc sample observed with the BOSS instrument under targeting plan 0.5.0 and uses the same selection criteria as mwm_snc_250pc.
mwm_snc_ext_main_apogee
This cart contains targets beyond 100pc. It applies a linear cut in absolute G-mag and distance to select increasinglymore massive stars at larger distances. 2MASS H-band brighter than 11mag.
Add some constraints on astrometric excess noise in crowded regions (Galactic plane, LMC, SMC). This carton contains 1/16 of the targets.
Selection Criteria
- gal_cut = ((l <= 180) AND (bb < (-0.139 * l + 25)) AND (bb > (0.139 * l – 25)))
OR ((ll > 180) AND (bb > (-0.139 * ll + 25)) & (bb < (0.139 * l – 25)))
OR (sqrt(pow(l – 303.2, 2) + 2 * pow(b + 44.4, 2)) < 5
OR (sqrt(fn.pow(l – 280.3, 2) + 2 * pow(b + 33.0, 2)) < 8) - 0 < parallax < 10
- G + 5 * log(parallax / 1000) + 5) < 19.125 – 0.03225 * (1000 / parallax)
- astrometric_excess_noise < 2 AND gal_cut OR NOT gal_cut
- H < 11
mwm_snc_ext_filler_apogee
This carton is the same as mwm_snc_ext_main_apogee, but contains the remaining 15/16 of the targets at lower priority.
mwm_snc_ext_main_boss
This carton uses the same criteria as mwm_snc_ext_main_apogee, but with the H < 11 replace with G > 10. 1/20 of the targets are in this carton.
mwm_snc_ext_filler_boss
This carton is the same as mwm_snc_ext_main_boss, but contains the remaining 19/20 of the targets at lower priority.
Cadences
During plate observations, targets could be observed with either the BOSS or APOGEE instrument. APOGEE observations were allowed on plates with any cadence, while BOSS observations were allowed on all plates except those with the RM cadence.
During FPS operations, all targets in the *_apogee cartons utilized the bright_1x1 cadence, while targets in the base *_boss cartons utilized either the bright_2x1 (for G < 16) or dark_2x1 (for G > 16) cadences.
In targeting generations v1.0.5 and v1.0.5-boss-only the *_boss criteria changed to bright_2x1 (for G < 16) or dark_2x1 (for G >= 16).
The mwm_snc_100pc_boss_single carton was introduced at lower priority to allow for a less ideal cadence of bright_1x1 (for G < 16) or dark_1x1 (for G >= 16) to be used if there were not resources for the preferred cadence. Likewise mwm_snc_100pc_bright_boss_single was introduced at a lower priority than mwm_snc_100pc_boss_single and has a cadence of bright_1x1 (for G < 18) or dark_1x1 (for G >= 18).
The carton mwm_snc_100pc_low_lum_boss_single has a cadence of dark_1x1.
For mwm_snc_ext_main_boss and mwm_snc_ext_filler_boss the cadence is bright_flexible_2x1 (for G < 16) or dark_flexible_2x1 (for G >= 16).