The Magellanic Genesis survey will map the kinematical and chemical structures of the Large and Small Magellanic Clouds (MCs) using APOGEE and BOSS spectroscopy. Intrinsically luminous O-rich and C-rich AGB stars will be used to fully map the main bodies of the MCs. By aiming to achieve S/N > 40 APOGEE spectra of these AGB stars, the Magellanic Genesis program will obtain comparable radial velocity and abundance precision as the Galactic Genesis program.
The outer peripheries of the MCs will be mapped with the more numerous population of red giant branch stars using the BOSS spectrograph.
Cartons
mwm_magcloud_agb_apogee
This carton uses Gaia DR3 photometry and astronometry to select AGB targets in the Magellanic Clouds. Selection is based on color, proper motion, and parallax cuts. The selection is done in two rounds. The first is a rough cut, and then that cut is post processed to select out the appropriate targets.
Selection Criteria Rough Cut
- parallax > 0 AND (parallax + 0.025 / parallax_error) > 5
- g_mag <= 18
- h_mag < 13
- bp_meanmag – rp_mean_mag > 1
- -3 < pmra < 3
- -3 < pmdec < 3
- Within a circle centered at RA=59.5, Dec=-72.8, Radius=30 Degrees
Selection Criteria Post Processing
The resulting stars from the rough cut are then transformed into the Magellanic Stream Coordinates from Niever et al. (2008) to give L, B, pm_B, and L_cosB.
- Require the following quantities to be finite: pmra, pmdec, parallax, and J,H,K magnitudes
- Sqrt((pm_L_cosB – 1.8)2 + (pm_B – 0.40)2) < 1.2
- B > (-1.5728745*L -19.292601)
- For LMC Targets
- (J-K, H) values within the polygon defined by (0.96, 12.35), (1.240, 12.35), (1.70,8.0), and (1.42, 8.0)
- For SMC Targets
- (J-K, H) values within the polygon defined by (0.90, 12.39), (1.180, 12.39), (1.64,8.4), and (1.36, 8.4)
mwm_magcloud_rgb_apogee
This carton uses Gaia DR3 photometry and astronometry to select AGB targets in the Magellanic Clouds. Selection is based on color, proper motion, and parallax cuts. The selection is done in two rounds. The first is a rough cut, and then that cut is post processed to select out the appropriate targets.
Selection Criteria Rough Cut
- parallax > 0 AND (parallax + 0.025 / parallax_error) > 5
- g_mag <= 18.5
- h_mag < 13
- bp_meanmag – rp_mean_mag > 1
- -3 < pmra < 3
- -3 < pmdec < 3
- Within a circle centered at RA=59.5, Dec=-72.8, Radius=35 Degrees
Selection Criteria Post Processing
The resulting stars from the rough cut are then transformed into the Magellanic Stream Coordinates from Niever et al. (2008) to give L, B, pm_B, and L_cosB.
- Require the following quantities to be finite: pmra, pmdec, parallax, and J,H,K magnitudes
- Sqrt((pm_L_cosB – 1.8)2 + (pm_B – 0.40)2) < 1.2
- Get ebv from dustmaps.sfd() https://dustmaps.readthedocs.io/en/latest/maps.html
- LMC Radius = Sqrt((L+0.6)2 + (B-3.6)2)
- SMC Radius = Sqrt((L+15.53)2 +(B+11.58)2)
- For High extinction regions where (LMC Radius <+ 4.5 OR SMC Radius <= 2.5) AND ebv > 0.1 rescale the ebv to ebv = ebv * 0.07
- AV = 0.86 * 3.1 * ebv
- G0 = G – 0.8509139481578785 * AV
- BP0 = BP – 1.0901361069987485 * AV
- RP0 = RP – 0.5894794093231802 * AV
- ((BP-RP)0 , G0) values within the polygon defined by (0.95, 17.5), (1.2649, 15.8064), (1.62255,15.2065), (1.9889, 14.6065), (2.4164, 14.0212), (3.1492, 14.6358), (4.283, 15.6162), (4.30, 16.24), and (3.3411, 17.5)
- Final G cut < 17.5
manual_mwm_magcloud_massive_apogee
These are massive stars in the Magellanic clouds selected selected from various massive star catalogs by Drew Chojnowski.
manual_mwm_magcloud_massive_boss
These are massive stars in the Magellanic clouds selected selected from various massive star catalogs by Drew Chojnowski.
manual_mwm_magcloud_symbiotic_apogee
These are symbiotic stars in the Magellanic clouds selected by Steve Majewski’s group using a variety of datasets.
Associated Open Fiber Programs
In DR19, a pilot program for Magellanic Genesis was implemented as part of the open fiber program under the following cartons:
- openfibertargets_nov2020_47a
- openfibertargets_nov2020_47b
- openfibertargets_nov2020_47c
- openfibertargets_nov2020_47d
- openfibertargets_nov2020_47e
Cadences
The spectra are taken with both the APOGEE and the BOSS spectrographs.
The mwm_magcloud_agb_apogee carton targets are assigned a cadence based on their H magnitude to achieve a signal-to-noise of at least 45.
![\[ N = \frac{60 min}{15 min} \times (45^2 / 100^2) \times 10^{(0.4 \times (Hmag-11)} \]](https://quicklatex.com/cache3/03/ql_e4577eeab23a1357f89c52818d217f03_l3.png "Rendered by QuickLaTeX.com")
Number of exposures = 
rounded to the nearest integer.
Number of exposures = 
rounded to the nearest integer.
Between 1 and 4 exposures is needed per epoch to achieve the requisite S/N, so the full list of cadences is:
- bright_1x1
- bright_flexible_1x2
- bright_flexible_1x3
- bright_flexible_1x4
All other carton targets utilize the bright_1x1 cadence.