APOGEE Targeting Information

Starting with 297,301 quasars of the SDSS-III/BOSS-DR12Q catalogue (Paris et al. 2015), we select 71,587 quasars that have a visual redshift in the range $2.06\le z \le 2.38$. This sample is further restricted by requiring Vega H-band magnitudes $<20$. However, only 20,796 quasars have H-band flux measurements from UKIDSS. For the remaining ones, we studied the correlation between UKIDSS H-band measurements and z-band SDSS magnitudes using quasars with UKIDSS H-band magnitude $<21$ (19,993 in total). Thus, for those quasars without H-band measurements we require z-band SDSS magnitude $<21.27$. Alternatively, we demand the H-band magnitude obtained either from UKIDSS or estimated from z-band SDSS measurements to be $<20$. In this way, we obtain a sample of 61,075 quasars. Only 971 are located in the APOGEE-2N halo fields (within a radius of 1.4 degrees from the center of the field). In each plate, our targets are prioritized by their H-band magnitudes.

Targets were selected by cross-matching the General Catalog of Variable Stars (GCVS; Samus et al. 2007-2012), restricted to those stars of normal Cepheid and delta Cepheid types (CEP and DCEP designations in the GCVS, respectively), to the APOGEE-2N field footprint. The GCVS Cepheid catalog is further restricted to those stars with H magnitudes between 6.5 and 11 to ensure that S/N of 100 is safely obtained in 1 hour (to avoid problems of co-adding spectra during different phases). While only those stars with periods longer than 7 days are expected to show a MIR-color metallicity relationship, sources with periods less than 7 days were included in the target selection to increase overlap with the Genovali et al. (2014, 2015).

For each pointing, targets are selected in the region of the field for which $A_H(D=7{\rm kpc}) \le 1.4$. This $A_H$ is computed from Marshall et al. (2006)'s 3D extinction map, using linear interpolation in distance and assuming $A_H/A_{Ks}=0.46/0.31$. Targets in this region are selected from the 2MASS catalog using the same 2MASS quality cuts and RJCE dereddening as the standard APOGEE disk targets. All potential targets are obtained by selecting stars with $(J?K_s)_0 \ge 0.8$ and $12 \le H \le 13$. A random subset of these are observed. Targets at the top of the list that were already observed as part of the regular disk sample in the $l = 34^\circ$ and $l = 64^\circ$ midplane fields are flagged, but not re-observed.

Our targets were selected according to very simple and somewhat subjective criteria. First, we obtained comprehensive lists of known OBA emission-line stars via SIMBAD, VIZIER catalogues, and papers. Next, we identified the stars falling in planned APOGEE-2 fields and assembled additional data for them, including spectral types and 2MASS magnitudes. For stars with suitable H magnitudes, we checked the literature and attempted to sort by sub-type, e.g. classical Be star, B[e] star, unclassified emission star, etc. Rare and unusual Be subtypes were targeted first, followed by the 6 members of NGC 7419.

We made an all-sky catalogue including all currently known members of Nearby Young Moving Groups, comprising more than 2000 stars across the sky. Of these, we selected stars with $7 \le H \le 12.2$ falling within planned APOGEE-2 fields, resulting in 9 stars with a variety of spectral types. We also selected 22 bright stars ($H \le 9.2$) with $\delta \ge -10$, filling in the gaps in spectral type, to be observed with the NMSU 1-m telescope.

All of our targets lie in the existing APOGEE field K21_071+10 and have $H \le 12$. They are drawn from several sources in order of priority: First, all stars observed optically by Geisler et al. (2012) meeting our S/N requirements were included, excluding those which already have APOGEE-1 spectra from DR12 or earlier, as none of these show evidence for the Na-O anticorrelation. The three Na-poor stars from Geisler et al. (2012) have been given top priority on our target list. Additional candidates were drawn from literature studies which provide membership information (Platais et al. 2011, Tofflemire et al. 2014, Bragaglia et al. 2014), excluding all known non-members. The remaining targets were drawn from 2MASS point sources which fall on the cluster upper RGB or RC in the color-magnitude diagram (again excluding known non-members from the above studies), and these are sorted in order of increasing radius from the cluster center out to the approximate tidal radius of ~24 arcmin (Dalessandro et al. 2015

The massive star sample was selected from a combination of near- to mid-infrared color-magnitude (CMD) and color-color (CCM) selection criteria, which are described in detail by Roman-Lopes (2016). The derived catalog was then cross-matched with known OB stars, using the SIMBAD database together with the catalogs of spectral classification of stars in the direction of W3-4-5.

The YSO sources were selected based on two different approaches. The first used Spitzer colors combined with X-ray detections, where available, to identify probable young star members. These are traditionally subdivided into three categories: Class I sources (deeply embedded protostars with large IR excesses), Class II sources (those with IR excesses typified by the presence of disks), and Class III sources (those lacking IR excesses, having had their disks dispersed). Targets were selected based on these criteria from the catalogues produced by Koenig et al. (2008), Koenig & Allen (2011), and Chauhan et al. (2011) for W5, and Rivera-Ingraham et al. (2011), Bik et al. (2012), and Roman-Zuniga et al. (2015) for W3-4.

A comprehensive search of all APOGEE-2N survey plate fields remaining to be drilled at the time of the ancillary call was conducted to locate rare stars within these fields for study. The focus was on massive high luminosity stars with early spectral types, and included supergiant and emission line stars, along with other rare objects. The search utilized Simbad and and the online WR star catalogue. A final subset of 15 stars in the range $6.5 \le H \le 12$ were selected, with an emphasis on observing all visits to study spectral variability of the stars.

The APOGEE Reddening Survey target selection is designed to be as similar to the main APOGEE target selection as possible, to allow these two surveys to be statistically compatible. We adopt the exact same criteria as for ordinary APOGEE targets, as detailed in Zasowski et al. 2013; we use only stars with $9 \le H \le 11.4$ mag, so that S/N of about 100 can be reached in a single visit to a plate. In addition: (1) we prioritize targets in regions of high or interesting reddening, (2) we demand that the targets have optical magnitudes from PanSTARRS-1 in at least two of the griz bands, to allow the optical reddening law to be studied, and (3) we demand that the RJCE $E(J-K_s)$ reddening estimate is greater than 0.2, to avoid looking at unreddened stars.

The Kepler Exoplanet Archive was searched for all Kepler and Kepler Objects of Interest (KOI) systems having input catalog effective temperatures of $T_e \le 4300$K. The primary emphasis for this project is to push abundance analyses to the M-dwarfs, but some overlap is allowed with late K-dwarfs. A $T_e$ cut at 4300K will include types K6 and K7, and these targets will provide overlap with abundance analyses from optical high-resolution spectra. SNRs were calculated for the number of planned visits given for each of the APOGEE-2 fields, and only those targets expected to yield a SNR $\ge 70$ were then included in the target list.

The targets were selected using four different sources: the General Catalogue of Galactic Carbon stars (Alknis et al. 2001), the Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (Acker et al. 1992), the Torun catalogue of Galactic post-AGB and related objects (Szczerba et al. 2007), and the PhD thesis of Pedro Garcia-Lario (1992, unpublished). A cross-match with the APOGEE-2N fields was performed, finally selecting the targets with 2MASS H-band magnitude $7.0 \le H \le 13.5$.