Subject: Review of Post-2008 APO Science Program Proposals

From: Ed Turner

Submitted: Sun, 17 Sep 2006 12:29:40 -0400 (EDT)

Message number: 983 (previous: 982, next: 984 up: Index)

This message is to inform you of the current status and of plans for the 
review of the post-2008 APO science proposals.

As was mentioned earlier, we received seven proposals.  The external 
science reviews have been completed, and an ARC-internal review panel 
has been formed and has met three times by telephone.  It plans to
continue to meet at least weekly.  The internal panel consists of
Rich Kron, Suzanne Hawley, Jim Gunn, Steve Kent, David Weinberg,
Rene Walterbos, Bruce Gillespie and myself.  Based on the comments 
from the external science reviewers and on other largely programmatic 
and technical criteria, the internal panel has begun to evaluate the 
proposals.  We will attempt to synthesize a program (or choice of 
programs) using one or more of the elements from the proposal pool. 
We expect to have completed this step by mid-October, and will then 
forward our recommendation(s) to the ARC Board of Governors.

In the spirit of keeping the ARC/SDSS-II community informed, we 
list below the titles, PI names, and abstracts of the seven 
proposals being considered.  Members of the ARC or SDSS communities
who are interested in specific projects are invited to contact the
PI.  Note that in some cases the person listed may not be the science
PI of the actual project if it is eventually carried out but is, in
any case, the appropriate contact person at this time.

Post-2008 proposals (title, PI, abstract):

Title: A Low-Redshift Supernova Survey Using the ARC 2.5m Telescope

PI: A. Becker (Univ. of Washington)

Abstract:  We propose to devote the ARC 2.5m telescope and its imager 
to a new supernova survey during the first ten months of operations 
after the end of SDSS II (Sept. 2008 through
June 2009). In combination with and building upon the success of the 
SDSS II Supernova
Survey, the ARC Supernova Survey (ARCSS) will discover and measure 
densely sampled, well-calibrated, multi-band optical light curves for 
~250 low-redshift type Ia supernovae, quadrupling the SDSS II sample 
in the range 0.05<z<0.15. This sample will be an order of magnitude 
larger than currently available low-redshift SN samples of comparable 
data quality. With less stringent quality cuts, the ARCSS sample will 
total ~500 light curves. The ARCSS survey efficiency will be well 
above 90%, resulting in an unbiased sample. The survey will also 
probe other supernova types, and its large volume will enable study 
of peculiar and relatively rare supernovae, including peculiar SNe Ia 
and Ib/c. To achieve such a high SN discovery rate, ARCSS will scan 
at three times sidereal rate. We will carry out tests to ensure that 
we can operate in this mode and obtain precision photometry using the 
associated binned readout; if that proves infeasible, scanning at 
sidereal rate will produce a sample five times larger than the 
comparable, current low-redshift sample. Spectroscopic follow-up 
observations to determine supernova types, obtain precise redshifts, 
and measure detailed spectroscopic features at several epochs per 
supernova will be provided by a number of telescopes around the 
world.  The proposed ARCSS sample will result in significantly 
improved anchoring of the Hubble diagram and understanding of 
supernova luminosity variations and K- corrections; combining this 
information with ongoing and future high-redshift surveys will lead 
to stronger and more robust constraints on the nature of the dark 

Title: A Post 2008 Proposal for the ARC/SDSS 2.5m - A Massive 
Spectroscopic Survey of the Galaxy

Contact author: Jill Knapp (Princeton)

Abstract: The overall scientific goals of this project, which is an 
extension of SEGUE, are detailed studies of Galactic kinematics, 
dynamics, and metallicity distributions; searches for the rarest 
objects, especially the lowest-metallicity objects; and support of 
Gaia science.

Operating full time except for the week or so around full Moon, the 
SDSS spectrographs on the 2.5 m can produce of order 300,000 spectra 
per year of stars to magnitude 19-20. SDSS-I and II plus six years of 
observing could measure radial velocities, stellar parameters (g, 
Teff) and abundances (both metallicity and alpha/Fe) for more than 2 
million stars, about 2% of those at declination > 0 whose parallaxes 
and proper motions will be measured by Gaia and complementing the 
Gaia and RAVE radial velocities which will be measured only for stars
brighter than about 16.5 (Gaia) and 12 (RAVE). The SDSS 
spectrographic system is still state-of-the-art and a complete 
observing, data reduction and data analysis system is in place, so 
this project could begin immediately at the end of SDSS-II. The 
proposed plan is to obtain some 900 square degrees of imaging of the 
anticenter direction in Fall 2008, and to acquire spectra thereafter, 
using SEGUE target selection and aiming for a filled-area survey 
within which the stars are randomly sampled.  [Full text available 
via anonymous ftp at gk/SSS (, 

Title: Mapping the Cosmic Web of Baryons with HST/COS and the ARC 
2.5m Imagers and Spectrographs

PI: John Stocke (Univ. of Colorado Boulder)

Abstract: To map the large-scale baryonic structure of the low-z 
universe in both gas and galaxies, we propose to use the Sloan 2.5m 
telescope to observe large-scale structure in galaxy fields around 
~20 AGN from our Hubble (COS and STIS) surveys of IGM absorbers.  We 
will observe two strips covering a 2.5 degree field per AGN, with 6-8 
hrs per AGN: two photometric scans of 1 hr each and two 1-hr 
spectroscopic plug-plates, to produce 700-1000 galaxies (r'~19) or 
3.5m DIS long-slit spectra, targeting galaxies whose photometric 
redshifts match known Lyman alpha absorbers.  We may also observe 
wider fields around a few targets with lower-redshift absorbers.  We 
propose to provide $250 K from Hubble/COS funds for ground-based 
observing, supplemented by support from other HST Guest Observers, 
from observing proposals to NSF, and from an STScI Legacy proposal 
for studies of QSO Absorption Lines.

Title: Synoptic Spectroscopy of Young Stars: A Proposal for the 
Apache Point Observatory 2.5 meter Telescope After 2008

PI: John Bally (Univ. of Colordao Builder)

Abstract: The 640 fiber multi-object spectrometer on the 2.5 meter 
will be used to measure basic stellar properties, spectroscopic 
variability, and to characterize the birth environments of young 
stars lying within a few kpc of the Sun with ages less than a few 
hundred million years, the period during which planet formation is 
completed.  Spectral typing will be used to generate HR diagrams for 
nearby clusters and associations, estimate stellar masses, ages, and 
radial velocities.  Repeated observations will be used to determine 
the time-scales for variations in accretion and mass ejection rates, 
identify companions, and transiting circumstellar material in edge-on 
disks. We will search for signatures of environmental effects on the 
formation and early evolution of planetary systems, including 
dynamical processes and radiation fields. The proposed survey will be 
a crucial step in the characterization of the local young star 
population of the Galaxy, a key step towards a comprehensive 
understanding of the formation of stars, clusters, associations, and 
their planetary systems throughout the Universe.  It will be a vital 
resource for interpreting other large synoptic surveys that only 
provide photometric data and provide data for target selection for 
future space missions such as JWST.  This program will primarily use 
the 2.5 meter spectrographs, supported by the 2.5m wide-field imaging 
capability, for spectral typing and synoptic monitoring of young 
stars.  We consider three funding scenarios: High level of funding 
would enable the observation of about 106 young stars and development 
of new spectrographs for R > 104 spectroscopy.  Operations with 
moderate funding enable us to monitor about 105 stars using the 
existing hardware.  We also consider what could be achieved in a 
`cheap operations=E2=80=99 mode using only a few custom plug plates to 
extensively monitor a representative sample of about 104 young star 
systems.   While other surveys of young stars concentrate on 
photometric variations, our program will focus on spectral properties 
and variability.

Title: The Apache Point Observatory Galactic Evolution Experiment 
(APOGEE) with the ARC H-band Echelle Spectrograph (ARCHES)

PI: Steven R. Majewski (Univ. of Virginia)

Abstract: We propose to use the ARC 2.5-m telescope to conduct the 
APO Galactic Evolution Experiment (APOGEE) survey, a large scale, R 
=E2=88=BC 20000 spectroscopic probe of low latitude Milky Way stars that
will provide, by orders of magnitude, the largest database of 
chemical abundances, spectroscopic parallaxes and kinematics for 
Galactic bulge and disk stars. The survey will be conducted with a 
dedicated, multi-fiber, cryogenic spectrograph operating in the near-
infrared H-band, ARCHES (ARC H-band Echelle Spectrograph), to be 
built at the University of Virginia. This survey would use 
approximately half of the time on 150 bright-time nights each year 
during a three-year period to observe of order 10^5
targets to S/N =E2=88=BC100. Approximately half of the targets will be =
the Galactic bulge/bar and half will span the Galactic disk. Giant 
stars, which are found in all Galactic stellar populations, are 
intrinsically bright in the H-band, while the Galaxy is substantially 
more transparent at 1.5=CE=BC than at visible wavelengths. These =
combined with the fact that 2MASS already provides ideal source 
selection, enable a survey that spans the full radial extent of the 
Galactic disk and bulge (H < ~13.5) without the need for a new 
photometric imaging program. The APOGEE spectroscopic database will 
provide the first three-dimensional view of the chemical abundance 
and kinematical distributions of stars in the inner Galaxy and outer 
disk, providing the strongest constraints yet on the formation and 
evolution of the Milky Way. The scientific objectives of this survey 
will be to (1) provide extensive chemodynamical data on the inner 
Galaxy (thin/thick disk, bar/bulge, low latitude halo substructure) 
sufficient to constrain formation/evolution models, (2) place 
constraints on the first stars from unbiased metallicity distribution 
functions of these stellar populations, (3) constrain and understand 
physical processes of star formation, feedback, mixing in the 
formation of the Galaxy, (4) survey the dynamics of the bulge and 
disk, and place constraints on the nature and influence of the 
Galactic bar and spiral arms, (5) attempt to isolate what portion of 
the disk and bulge come from accretion versus formation in situ.

Title: Refining the Distance Scale to 1% with the ARC 2.5-m Telescope

PI: David Schlegel (Lawrence Berkeley National Laboratory)

Abstract: We propose to use the SDSS facility post-2008 to conduct 
the largest spectroscopic survey to date of cosmological large-scale 
structure. The survey is designed to use the baryon acoustic 
oscillation phenomenon to make significant improvements in our 
measurements of the cosmic distance scale and hence the acceleration 
of the expansion rate of the Universe. The primary goal is a survey 
of Luminous Red Galaxies (LRGs) out to z ~ 0.7 over 10,000 square 
degrees, aimed at the measurement of the baryon acoustic peak in the 
large-scale galaxy correlations. A secondary survey of z > ~2.5 
quasars (using a small fraction of the fibers) will allow us to 
measure the acoustic oscillations at z =3D 2.5 in the Lyman  forest. 
This data set will yield absolute distance measurements of 1.1% at z 
=3D 0.35, 1.1% at z =3D 0.6, and 1.4% at z =3D 2.5. More generally, this =
APO-LSS survey will be up to 9 times more effective at measuring 
large-scale structure than the full SDSS-II.
    This survey requires full use of grey and dark time of the 2.5-m 
telescope for 4 years. Improvements will be made to the spectrographs 
primarily by replacing the fibers, gratings, and CCDs. If deemed 
feasible, an automated fiber actuator system would replace the plug-
plate system, significantly improving flexibility and running costs 
of the instrument.
    Our baseline plan involves running the imaging camera through 
fall 2008, and only the spectrographs beyond then. Our budget assumes 
that 1/3 of the time (bright time) will be covered by another 
program. The Photometric Telescope will not be used.

Title: An All Sky Extrasolar Planet Survey (ASEPS) with the APO 2.5m 

PI: Jian Ge (Univ. of Florida)

Abstract: The extrasolar planet discoveries in the last decade have 
revolutionized and reinvigorated planetary science. More than 190 
planets with ~5 Earth masses to ~10 Jupiter masses are now known to 
orbit nearby sun-like stars. These extrasolar giant planets reveal an 
astonishing and unexpected diversity of masses, semi-major axes and 
eccentricities. The observed planet demographics have challenged the 
planet formation paradigm that giant planets form and reside only in 
circular orbits at large distances from their parent stars, as is the 
case in our solar system. Despite the wide range of planet masses and 
orbital parameters, planet formation does not appear to be random. 
Definite classes of planets are emerging, hinting at the mechanisms 
that sculpt the final distribution of planets in a given planetary 
system. The discovery of many more planets are required to better 
understand planet formation, planet migration and evolution, the 
range of physical characteristics of extrasolar planets, and the 
relationship between planet formation and host star properties and 
environments. By increasing the planet sample from ~200 to ~10,000 
and extending the host star mass range from 0.4-1.5 solar masses (the 
main mass range for current surveys) to 0.08-5 solar masses, the All 
Sky Extrasolar Planet Survey (ASEPS) will fuel the next generation of 
extrasolar planet science.

We propose to use the Sloan 2.5-m wide field telescope and new 
generation multiple object high throughput Doppler instruments to 
undertake a large-scale visible and near-IR band Doppler survey of 
~250,000 relatively bright stars (generally V < 13 for the visible 
and J < 11 for the near IR) for extrasolar planets between 
2008-2013.  If this program is successful, we envision continuing the 
survey until 2020 to survey an additional ~250,000 stars and obtain 
information on long-period planets and possibly detect hundreds of 
solar analogs. Following the spirit of the original SDSS goal of 
increasing the number of known quasar and galaxy redshifts by over 
one order of magnitude, ASEPS aims to increase the number of 
extrasolar planets by nearly two orders of magnitude (~10,000 planets 
in the 12-year survey). The dramatic increase in the number of known 
planets will allow astronomers to study correlations and physical 
relationships much more effectively than at present. Additionally, 
the large number of planet discoveries will enable to detection of 
rare planets that may have eluded previous planet searches.  Thus, 
ASEPS will be the =E2=80=9Cnext generation Sloan Survey=E2=80=9D both in 
terms of 
the tools used and the scientific legacy.

The full ASEPS program would detect ~10,000 planets, spanning a wide 
range of planet properties. The ASEPS visible-wavelength survey has 
the sensitivity to detect giant planets at Jupiter-like distances (5 
AU) from parent stars with V < 11. The near-infrared survey will 
focus on M stars and may lead to discoveries of super Earth mass 
planets (~10 Earth masses) in the habitable zones (temperatures 
consistent with liquid water) around the low mass stars (~0.3 solar 
mass). Some of the short-period planet candidates uncovered by the 
survey will be observed with other telescopes in order to increase 
planet detection efficiency while longer-period planet candidates 
(several years) and the remaining short-period planet candidates will 
be monitored with ASEPS itself. This survey will also provide 
complementary work for future space planetary mission programs such 
as Kepler, Space Interferometry Mission (SIM)
and Terrestrial Planet Finder (TPF) by understanding planetary system 
characteristics and frequency among stars with an unprecedented mass 
range, providing an observational target list for determining planet 
size and mass through planet transit detection, and discovering a 
number of transiting planets around bright stars for space 
observations of planet atmospheric compositions.

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