Over a dozen science projects have been defined. They reflect the interests
of current participants in the survey; more projects are envisioned
as the collaboration grows, in particular as new post-docs join
the team. Many of the current projects would benefit from additional
(wo)manpower, so new postdocs and thesis students could play a major
role; interested parties are invited to contact us.
1. Properties of Lyman Alpha Emitters, Lyman Alpha Blobs, Lyman Break Galaxies, Optically-selected High-redshift AGN and Their Absorption Systems
(Gawiser, Blanc, Ciardullo, Feldmeier, Francke, Gronwall, Infante, Lira, Lopez, Maza)
Deep narrow-band imaging at 5000A has yielded a sample of over 200 Lyman
alpha emitters, which are very low-dust galaxies in the initial phase of
We are also studying extended Lyman Alpha emission
from the so-called Lyman Alpha Blobs, whose physical origin is still
uncertain between extended starbursts, obscured AGN, or cooling radiation
from the initial collapse of dark matter halos.
Deep UBVRIz' imaging allowed us to find high-redshift (3<z<5)
Lyman break galaxies (LBGs) through their dropout from the U,
B, or V filter and flat spectra in the redder filters.
We found about 5000 LBGs at z=3, 2000 LBGs at z=4,
and 500 LBGs at z=5, representing a factor of several increase
versus previous samples.
Our optical through NIR photometry allows us to improve on recent
measurements of the LAE and LBG contribution to the star formation history of
the universe at redshifts of three and higher. Clustering analysis
has determined the typical dark matter halo mass for each set of objects.
We will also identify and study Damped Lyman alpha Absorbers and other
absorption systems in the spectra of bright AGN discovered
in this survey.
2. Massive Galaxies at High Redshift
(van Dokkum, Franx, Kriek, Labbe, Marchesini, Quadri, Rudnick, Taylor, Yi)
Deep optical+IR imaging allows the selection of galaxies in the
rest-frame optical at z>2.
The deep, central fields of
the MUSYC survey comprise the deepest uniform UBVRIzJHK data
available in any field of comparable size. We are studying
the clustering properties of K-selected galaxies at 2<z<3.5
(Quadri et al), their luminosity function (Marchesini et al),
rest-frame optical spectra (Kriek et al), masses
(van Dokkum et al), and other properties. We are also studying
the properties of 1<z<2 galaxies in the E-CDFS (Taylor
et al), and Spitzer data awarded in Cycle 3 (Labbe et al).
3. AGN Demographics and the Co-Evolution of AGN and Galaxies
(Urry, Cardamone, Coppi, Koekemoer, Lira, Maza, O'Dowd, Simmons, Treister, van Dokkum, Van Duyne, Virani, Webster)
We initially concentrated on constraining the fraction of obscured AGN
at the QSO era, z~2. In a series of papers, Treister and Urry and
collaborators have shown there is a substantial population of obscured
AGN out to high redshift; most recently, Treister & Urry (2006, ApJ, in
press) showed the fraction of obscured AGN must increase at z>1. In the
ECDF-S, we have found several dozen extreme objects (EXOs) that are
bright in X-rays and infrared but faint in the optical; these may be
intermediate redshift, dusty and obscured AGN, or high-redshift (z>6)
AGN. Follow-up near-infrared spectroscopy with Gemini is underway to
distinguish these possibilities. Now we are focusing on the evolution of
supermassive black holes, and in particular, on feedback processes
between the AGN and galaxy. Radiation and energetic outflows from the
AGN can have a profound effect on star formation activity in the galaxy;
similarly, stellar processes and interactions with other galaxies can
impact accretion. We have used the MUSYC data to generate a uniform hard
X-ray-selected sample of AGN, starting first in the ECDF-S (see
which presents a careful analysis of the Chandra survey
data and X-ray catalog) and 1030 fields.
We are studying the broad-band spectral energy distributions (SEDs) and
measuring bolometric luminosities. We also are analyzing the host galaxy
morphologies, masses, ages, metallicity, and stellar content, and
galaxy environments. Using several independent methods to estimate
black hole masses (from broad lines, reverberation mapping, stellar
velocity dispersions, or host galaxy bulge luminosity), we determine
Eddington ratios and compare black hole to host galaxy properties. The
goal is to learn in detail how feedback between galaxies and
supermassive black holes happens, and to determine the relevant sequence
and time scales for galaxy assembly and black hole growth.
4. Galactic Structure/Proper Motion Survey (Altmann, Mendez, Ruiz, van Altena)
The MUSYC project will play an important role in characterizing
the stellar density and scale height of the Milky Way disk and in
finding new brown dwarf candidates to a deeper
magnitude than any of the previous dedicated surveys. The combination
of NIR depth and a proper-motion survey with a two-year baseline covering
the combined MUSYC and CYDER fields will
allow the detection of late-L/early-T type BDs out to distances of
90 pc. White dwarfs are tracers of the age and evolution of the
Galactic disk and halo. With the MUSYC data we will be able to detect the
faint end of the halo field WD luminosity function by using the oldest WDs
present in the full square degree of data. This will allow us to
constrain the amount of baryonic dark matter in the form of WDs, which
is a key clue to the long-standing dark matter mystery.
5. Properties of K-selected Galaxies (Lira, Barrientos, Blanc, Castander, Infante, Padilla, van Dokkum)
A number of scientific analyses will be possible with our wide NIR images,
including K-selected galaxy luminosity functions and measuring the angular
correlation function of K-selected galaxies. Given the detection limits of
the MUSYC wide NIR survey, these objects will primarily be at z<2.
6. Evolution of the Galaxy Correlation Function at z<2 (Padilla, Infante)
Using photometric redshifts, we measure the galaxy correlation function
in several redshift bins and infer its evolution. Comparison with
mock catalogs allows us to check for systematic uncertainties
in the method.
7. Morphologies of Red Galaxies at 1<z<2 in the ECDF-S (Franx, Pasquali, Rix, Rudnick, Taylor)
We are conducting a simple morphological study of luminous red galaxies
in the range 1 < z < 2. Redshifts are provided by Rudnick's code,
and all the rest is based on GEMS and (if
necessary) GOODS imaging. Substantially, we aim to
measure Sersic indices and sizes as a function of
the GEMS (V-z) color of the selected galaxies, so
to extend the work previously done by Bell et al (2004,
ApJ 600, L11) up to z = 2.
8. High-redshift Quasars
(Maza, Francke, Gawiser, Lira, Liu, Treister, Urry)
will be deep enough to find over 100 quasars down
to I=25 and will therefore probe the low-luminosity end of the
high-redshift quasar luminosity function
as a function of redshift.
Only a few quasars are known
at z>5.5, but extrapolating the lower-redshift luminosity function
implies that we should find several as R-dropouts, using the (I-z)
and (where available) near-infrared colors to distinguish these galaxies from
L and T dwarfs (which are scientifically interesting interlopers).
Indeed, our survey is sensitive to quasars and lensed LBGs at
6<z<6.5 which are I-dropouts but blue in (z-J).
9. Star Formation History of Ellipticals (Yi, Kaviraj, Schawinski)
Using GALEX/SDSS early-type galaxies we found
a substantial fraction (>15%) of nearby (z=0.05-0.13)
bright (Mr<-22) early-types are showing evidence of
recent star formation (RSF), that is unexpecetd high
UV flux. Such a finding is provocative especially because
such massive early-types (whether pure Es or S0's) are
not often thought to have much RSF.
As a formal GALEX paper, we propose to explore a deeper universe
up to z=0.3 using GALEX DIS survey on CDFS (public)
and optical-IR MUSYC database.
Additionally, as a purely MUSYC effort, we propose to measure restframe NUV
and optical photometry on z~0.5 galaxies (2500A will
appear as U at z=0.5). We don't need galex data for this.
By comparing these z=0.5 red galaxies properties to
nearby universe data, we will try to learn the SFH in early
types. We will compare the data to semi-analytic models
we build in house. E+A galaxies will be discussed as well.
We expect to find a few hundred
red galaxies at intermediate redshifts in ECDFS field.
We will try to classifiy them morphologically and
via other methods (frac_dev, sersic index, etc.).
10. Search for Groups and Clusters (Christlein, Castander, Kannappan)
The primary effort is to search for groups out to z=1 as overdensities
in angular position and photometric redshift.
We will use the high-quality color information over a full square-degree
to search for high-redshift clusters using the red-sequence technique.
Our survey covers less area than surveys such as RCS but goes deeper in
many more photometric bands, which is a significant advantage in probing
less massive clusters at high redshift.
11. Galaxy Luminosity Functions (Christlein, Kannappan, Lin, Liu, Padilla)
Being studied at z<1 with optical selection as a function of redshift,
stellar mass, spectra type, color, and baryonic mass.
12. Low Surface Brightness Galaxies (Galaz, Rubio, Treister)
Due to the small sampled volume at low z of
narrow pencil beam surveys, low surface brightness
galaxies (LSBs) have been missed for decades.
This survey will have
enough width to find roughly 100 LSBs, thereby doubling
the sample known at present,
and it will have
enough depth and spatial resolution to detect LSB galaxies with a larger
range of sizes and colors than previous surveys.
The combination of U-band with R and K
will allow us to discover both very blue and very red LSBs,
with a better constraint for both metallicity and age
through comparison with spectrophotometric models and spectroscopy.
We will study the stellar population, star formation rate, metallicity,
dust, rotation curves, clustering environment,
and redshift evolution of these galaxies.
13. Nearby Bright Galaxies (van Dokkum, Lira)
Our exquisitely deep optical imaging allows us to study
nearby high surface-brightness galaxies, including low surface-brightness
features they may possess.
14. Lensing Statistics of Quasars (Lopez, Barrientos)
The Lambda CDM model makes a clear prediction that there should not
be any lensed quasar pairs down to m=23 in our square degree of sky.
We are testing this by obtaining spectra of at least one of each pair of
color-selected candidate double quasars, i.e. two point sources within
10" with extremely similar colors.
15. Evolution of Physical Parameters of Galaxies at z<1.5 (Kannappan,Christlein, Galaz, van Dokkum)
We will construct color-stellar mass distributions
of galaxies along the red and blue sequences
at intermediate redshift and examine the evolution of the
critical mass, star formation rates and histories, morphologies,
environments, and gas-to-stellar mass ratios within this context.
16. The Star Formation History at z<3 (Castander, Liu)
Using the rest-frame UV luminosity density measured from our survey
using our high-quality UBVRIzJHK photometric redshifts
it will be possible to compare results at z<3 with those of the
Canada France Redshift Survey and obtain an improved measurement
of the cosmic star formation rate during the crucial epoch at z>1 when the
majority of present-day stars were formed.
17. Education and Public Outreach (Liu, Gawiser, Maza)
We will include our exquisite multiwavelength data in the Digital Universe
project of the Hayden Planetarium, thereby offering the public four
pencil beam views of the distant universe in technicolor with an accompanying manual explaining the scientific topics being explored with these data.
We will use the bilingual nature of our collaboration to produce a Spanish
version of all of these materials, enabling outreach to the Spanish-speaking
people of the U.S., Chile, Spain, and the rest of Latin America.