Gemini Adaptive Optics Program
Science Drivers

The Gemini Observatory Mission is to address compelling astrophysical questions by providing state-of-the-art, productive observing capabilities that will enable the Gemini community to be a leader in OIR ground-based astronomy.

1. Science Drivers for Phase 1

As an illustration of the astronomical programs which benefit from the adaptive optics system, Simon Morris (currently at Durham University) led a team at the Herzberg Institute of Astrophysics to assess the science drivers for an adaptive optics system on the Gemini telescopes. The following table summarizes this study.

Table 1. High Priority Science Cases for Gemini AO [ Simon et al. 1997]

Project	Prime Band	Observation Band	Field-of-view [a]	Magnitude Range (I)	Number of Objects [b]	Resolution [c] (arcsec)	Desired Strehl Ratio [d]	NGS Sky Coverage [e]	LGS Sky Coverage [e]
Brown Dwarfs and M stars (images)	H	J-K	<10 arcsec	12-20	1	0.1	0.5	own	own
Young Stellar Object Disks (images)	H	J-K	<10 arcsec	12-20	1	0.1	0.5	own	own
Planet Searches (images)	H	J-K	<5 arcsec	20-29	1	-	0.5	own	own
Studies of Star Formation (spectra)	K	K	20 arcsec	-	1	<0.1	0.5	non- random	non- random
Local Group Star Clusters (images)	K	J-K	20 arcsec	20-26	100	<0.1	0.3	9%	90%
Local Group Young Stars (spectra)	K	I-K	10 arcsec	18-20	~20	0.3	0.2	22%	100%
Local Group Old Stars (spectra)	K	I-K	10-20 arcsec	20-23	10-100	<0.3	0.3	9%	90%
Galaxy Nuclei Dynamics (spectra)	K	I-K	10 arcsec	14-17	1	<0.1	0.3	9%	90%
Starburst Galaxies (spectra)	K	J-K	20 arcsec	19-23	10-20	<0.3	0.2	22%	100%
QSO Hosts (images)	H	I-K	20 arcsec	18-23	2-4	0.3	0.3	non- random	non- random
QSO Hosts (spectra)	H	I-K	20 arcsec	15-21	2-4	0.1	0.2	non- random	non- random
Gravitational Arcs (images)	H	I-K	20 arcsec	19-23	1-10	<0.1	0.3	0.6%	7%
Gravitational Arcs (spectra)	H	I-K	20 arcsec	19-23	1-10	<0.1	0.3	0.6%	7%
z<3 Galaxies and Clusters (images)	H	I-K	30 arcsec	20-26	~60	0.2	0.2	4%	56%
z<3 Galaxies and Clusters (spectra)	H	I-K	30 arcsec	19-24	~40	0.2	0.2	4%	56%
z<3 Galaxies and Clusters (images)	K	I-K	30 arcsec	20-26	~60	0.2	0.2	22%	100%
z<3 Galaxies and Clusters (spectra)	K	I-K	30 arcsec	19-24	~40	0.2	0.2	22%	100%

[a] Minimum diameter region to enable major science over which one would get the Strehl given in column 6 or better.
[b] Estimate of number of targets within the minimum diameter region. (Clearly this is a strong function of magnitude for many of these cases.)
[c] For imaging, scale lengths. For spectroscopy, slit widths.
[d] Estimates of Strehl needed to get sufficient resolution for imaging, or S/N and spatial resolution for spectroscopy, at perimeter of minimum diameter region. The value in this column results from a trade-off between all the numbers in the previous 4 columns. For example, for crowded field imaging, a high Strehl is needed to minimize the problems with halos of bright stars. For faint object spectroscopy, a lower Strehl may be useful if it gives one a larger field-of-view and hence more objects at once.
[e] 'own': cases where the science targets act as their own guide stars, 'non-rand.biased': cases where the target catalogs are biased away from bright stars, '% ': percentage sky coverage for the stated Strehl in the prime band using models from B. Ellerbroek.
NB NGS and LGS sky coverage for wind at angle to slit and with J+H OIWFS.

2. Science Drivers for Future Gemini AO

An assessment of the sky coverage gains from a laser beacon guide star adaptive optics system produce strong scientific drivers to advance the capabilities of the Gemini adaptive optics program to sodium laser guide stars. The Future Gemini Instrumentation workshop held in Abingdon, UK on January 18-19th, 1997 addressed the science drivers for future Gemini instrumentation program. The outcome of this program is summarized in the Gemini report RPT-PS-G0075 : Future Gemini Instrumentation. A summary table from this workshop is presented below.

SCIENTIFIC PROGRAMS	A&G Polarization Modulator		AOS		IR Imager/ Coronagraph	IR MOS						Hi Stab Lab Spec
Table 2 - Science Drivers for New Instrumentation Capabilities
	A&G Polarization Modulator		LGS >0.4	NGS >0.9		>3' FOV		AO		IFU		Hi Stab Lab Spec
	0.4-1µm	1-5µm	LGS >0.4	NGS >0.9		30K	5K	30k	5k	30k	5k	150k	300k	500k
A. Stars & Planetary System
--BD & giant planets				X	X					X	X	X	X
--physics of nearby stars							X		X				X
--stars in other galaxies			X		X		X		X		X
--surface structure/active processes	X	X	X										X
B. Star Formation & ISM
--initial mass function			X		X				X
--molecular clouds & cores
--disks & envelopes		X	X		X					X
--young substellar objects			X		X						X	X		X
C. Galactic Structure & Nearby Galaxies
--massive stars			X						X		X	X
--star clusters			X		X				X		X
--galactic nuclei			X		X				X		X
D. Formation & Evolution of Galaxies/Cosmology
--evolution of galaxies			X				X		X		X
--studies of AGN's	X	X	X		X				X		X
--galaxies probes of HiZ structure			X				X		X
--QSO's as probes of HiZ universe			X		X						X			X

SCIENTIFIC PROGRAMS	UPGRADES							SHARED INSTRUMENTS
Table 3 - Science Drivers for Upgrades to Phase I Instruments
	HROS R=120k	MK AOS LB	GMOS			NIRS		MICHELLE	PHOENIX
	HROS R=120k	MK AOS LB	0.1" IFU	1-1.5µm	R=25k	IFU	R~25k	MICHELLE	PHOENIX
A. Stars & Planetary System
--Brown Dwarfs & giant Planets	X					X		X	X
--physics of stars	X								X
--stars in other galaxies	X				X		X		X
--active stars								X	X
B. Star Formation
--initial mass function		X
--molecular clouds & cores							X	X	X
--disks & envelopes		X				X	X	X	X
--young substellar objects		X	X
C. Galactic Structure & Nearby Galaxies
--massive stars	X								X
--star clusters	X	X	X		X	X	X	X
--galactic nuclei	X	X	X		X	X	X	X
D. Formation & Evolution of Galaxies/Cosmology
--evolution of galaxies		X	X	X	X
--AGN's		X	X	X
--galaxies as probes of structure		X	X	X	X
--QSO's & Hi-Z universe	X	X	X	X	X			X	X

Page Compiled by Mark Chun. Last update January 18, 2000; Francois Rigaut

Gemini Adaptive Optics Program Science Drivers

1. Science Drivers for Phase 1

2. Science Drivers for Future Gemini AO

Gemini Adaptive Optics Program
Science Drivers