Spectro-Polarimetric High-contrast Exo-planet REsearch

SPHERE Observing Modes

The primary observing modes of SPHERE a re summarized in the table below:

Mode	Sub-Mode	Description			Science case
		Module/Spectral Range	De-rotator	Set-up/options
IRDIFS	NIRSUR	Simultaneous IFS(Y-J) + IRDIS/DBI (H)	pupil stab.	Dedicated coronograph	Large survey for exo-Planet detection in NIR, hundreds of targets
	NIR OBS		pup. or field stab.	any or no coronagraph	Specific characterization with IRDIS and IFS
IRDIS alone	DBI	Dual band Imaging, any filter pair Y-Ks	Pupil or field stab.	Any or no coronagraph	Characterization of companions in outer field, confirmations
	DPI	Dual Polarimetric Imaging	Field (pseudo) stabilized or fixed	Any or no coronagraph CP HWP in	Polarized circumstellar sources, e.g. disks
	LSS	Long Slit Spectroscopy	Field stab.	Low or medium resolution	Characterization of known companions
	CI	Classical Imaging Any BB/NB filter, Y-Ks	Pupil or field stab.		Genral use NIR high-res imaging
ZIMPOL alone	P1	High-precision relative polarimetry Any BB/NB filter	fixed (i.e. no de-rotation at all)	Any or no cornagraph CP HWP in	Highest precision polarimetry mode
	P1	Polarimetry mode with de-rotation Any BB/NB filter	Field stab.	Any or no cornagraph CP HWP in	High precision polarimetry mode for fainter targets
	P3	Polarimetry with de-rotator close to P1 position Any BB/NB filter	"pseudo" field stab. (single integrations stabilized)	Any or no cornagraph CP HWP in	High precision polarimetry with reduced de-rotator polar and cross-talk
	I	Imaging Any BB/NB filter	Field stab. or de-rotator fixed	Same or distinct filters in 2 arms Any or no coronagraph CP HWP out, modulation off	High-res imaging in the visual, differential NB imaging

The NIR survey mode is the main observing mode which will be used for ~80% of the observing time. It combines IRDIS dual imaging in H band with imaging spectroscopy using the IFS in the Y-J bands. This configuration permits to benefit simultaneously from the optimal capacities of both dual imaging over a large field (out to ~5" radius) and spectral imaging in the inner region (out to at least 0.7" radius). In particular, it allows to reduce the number of false alarms and to confirm potential detections obtained in one channel by data from the other channel. This will be a definitive advantage in case of detections very close to the limits of the system.

The NIR characterization mode, in which IRDIS is used alone in its various modes, will allow obtaining observations with a wider FOV in all bands from Y to short-K, either in dual imaging or dual polarimetry, or in classical imaging using a variety of broad and narrow-band filters. This will be especially interesting in order to obtain complementary information on already detected and relatively bright targets (follow-up and/or characterization). Spectroscopic characterization at low or medium resolution will be possible in long-slit mode. Additional science cases will also benefit from these observing modes (disks, brown dwarfs, etc.).

The visible search and characterization mode, will benefit from ZIMPOL polarimetric capacities to provide unique performance in reflected light very close to the star, down to the level required for the first direct detection in the visible of old close-in planets, even if on a relatively small number of targets. ZIMPOL also provides classical imaging in the visible, offering unique high-Strehl performance.