All Extragalactic: Minchin, R., Davies, J., Disney, M., Grossi, M., Sabatini, S., Boyce, P., Garcia, D., Impey, C., et al. 2007, High Resolution HI Imaging of VIRGOHI 21—A Possible Dark Galaxy in the Virgo Cluster, Ap.J., 670, 1056 Trump, J., Impey, C., McCarthy, P., Elvis, M., Huchra, J., Brusa, M., Hasinger, G., Schinnerer, E., Capak, P., Lilly, S., and Scoville, N. 2007, Magellan Spectroscopy of AGN Candidates in the COSMOS Field, Ap.J.Supp., 172, 383 Sasaki, S., et al. (29 authors, including C.D. Impey) 2007, A Potential Galaxy Threshing System in the COSMOS Field, Ap.J.Supp., 172, 511 Takahashi, M., et al. (34 authors, including C.D. Impey) 2007, The 3727 Luminosity Function and Star Formation Rate at z ~ 1.2 in the COSMOS 2 Square Degree Field and the Subaru Deep Field, Ap.J.Supp., 172, 456 Manieri, V., et al. (28 authors, including C.D. Impey) 2007, The XMM-Newton Wide-Field Survey in the COSMOS Field. IV. X-Ray Spectral Properties of Active Galactic Nuclei, Ap.J.Supp., 172, 368 Brusa, M., et al. (34 authors, including C.D. Impey) 2007, The XMM-Newton Wide-Field Survey in the COSMOS Field. III. Optical Identification and Multiwavelength Properties of a Large Sample of X-Ray Sources, Ap.J.Supp., 172, 353 Finoguenov, A., et al. (33 authors, including C.D. Impey) 2007, The XMM-Newton Wide-Field Survey in the COSMOS Field: The Statistical Properties of Clusters of Galaxies, Ap.J.Supp., 172, 182 Smolcic, V., et al. (22 authors, including C.D. Impey) 2007, A Wide-Angle Tail Radio Galaxy in the COSMOS Field: Evidence for Cluster Formation, Ap.J.Supp., 172, 295 Capak, P., et al. (58 authors, including C.D. Impey) 2007, First Release COSMOS Optical and Near-IR Data and Catalog, Ap.J.Supp., 172, 99 Sanders, D., et al. (42 authors, including C.D. Impey) 2007, S-COSMOS: The Spitzer Legacy Survey of the Hubble Space Telescope ACS 2 Degree COSMOS Field. I. Survey Strategy and First Analysis, Ap.J.Supp., 172, 86 Lilly, S., et al. (77 authors, including C.D. Impey) 2007, zCOSMOS: A Large VLT/VIMOS Redshift Survey Covering 0 < z < 3 in the COSMOS Field, Ap.J.Supp., 172, 70 Schinnerer, E., et al. (14 authors, including C.D. Impey) 2007, The VLA-COSMOS Survey. II. Source Catalog of the Large Project, Ap.J.Supp., 172, 46 Scoville, N., et al. (55 authors, including C.D. Impey) 2007, COSMOS: Hubble Space Telescope Observations, Ap.J.Supp., 172, 38 Taniguchi, Y., et al. (30 authors, including C.D. Impey) 2007, The Cosmic Evolution Survey (COSMOS): Subaru Observations of the HST Cosmos Field, Ap.J.Supp., 172, 9 Scoville, N., Aussel, H., Brusa, M., Capak, P, Carollo, C., Elvis, M, Giavalisco, M., Guzzo, L., Hasinger, G., Impey, C.D., et al. 2007, The Cosmic Evolution Survey (COSMOS): Overview, Ap.J.Supp., 172, 1
All Extragalactic: C. Peng, C. Impey, C. Keeton (Chicago), E. Falco (Whipple), C. Kochanek (Ohio), B. McLeod (CfA), J. Munoz, and H.-W. Rix (MPIA) of the CASTLES (CfA-Arizona Space Telescope - Lensing Survey) collaboration are using the Hubble Space Telescope (HST) to conduct an imaging survey of strong gravitational lens systems. Among some of the goals of the survey are to confirm new lens candidates, to study the geometry of the lenses, to use lensing to study cosmology, the lensing galaxies, and the evolution of galaxies. The CASTLES survey program has been awarded 130 orbits in total and followup data is being obtained using the excellent imaging quality of the Magellan telescopes. The work was a majority of the Ph.D. thesis of Chien Peng and it appeared in print in several papers in 2007. C. Peng and C. Impey have developed an algorithm, LENSFIT, to fit all objects in the observed images from the CASTLES lens survey directly, while simultaneously accounting for the lensing distortion. The difficulty in extracting quasar host galaxies caused by the high contrast between the central quasar and the diffuse underlying emission is well known. While the lensing distortion facilitates detection and detailed studies of the host galaxies, the arcs/Einstein rings must be de-projected via lens models to measure their intrinsic properties. Given a lens model with adjustable parameters, light from the host model is ray-traced into the foreground (image plane) to construct an image, which is matched to the data by varying the Sersic parameters and the lens model. The quasar images can also be modeled in the same way. A. Marble and C. Impey have an HST Legacy Archive project to study Lyman alpha absorbers in the nearby universe, drawn from the accumulated HST archive. Using data taken with the Faint Object Spectrograph, the Goddard High Resolution Spectrograph, and the Space Telescope Imaging Spectrograph we are producing line lists for 68 observed quasars, yielding more than 500 Lyman alpha absorbers in the redshift range 0 < z < 0.2. This sample substantially exceeds the statistics of the HST Key Project at such low redshifts and it will significantly improve the analysis of large scale clustering of Lyman alpha absorbers. In addition to preprating the ground for studies with the sonn-to-be-launched Cosmic Origins Spectrograph, this archive analysis will be used to give a legacy of UV spectroscopy analysis for the properties of the low redshift IGM. This is the only QSO absorption line project to be awarded Legacy Archive status. A. Marble and C. Impey, in collaboration with L. Miller (Oxford), have discovered a pair of QSOs separated by 33 arcseconds which is either a Mpc-scale binary QSO system or the most widely lensed QSO known. Because only galaxy clusters can cause such large separations, the statistics of wide lenses probe the abundance of the most massive collapsed structures in the Universe. This provides a test for simulation predictions of how structure has evolved from fluctuations in the CMB era at z~1000 to z=0 and a constraint on the dark energy equation of state parameter, w. Multiwavelength studies are being conducted to test the true nature of this object. This same team is also conducting a radio survey of QSO pairs of similar color at the VLA. Because radio properties of QSOs vary greatly and luminosity amplification from lensing is wavelength independent, optical and radio measurements can be used in tandem to identify candidate lensed QSOs. This work was part of Andrew Marble's Ph.D. thesis and will be submitted for publication in 2008. B. Lei, C. Petry and C. Impey are studying the echelle resolution HST spectra of 3C 273 and a quasar only one degree away on the sky. This unusual configuration offers the possibility of measuring the coherence of very low redshift Lyman alpha absorbers, in a region where galaxies have been very well studied. The transverse separations probed by the sightlines range from 100 kpc to 10 Mpc. The absorber show almost no clustering on the scale of galaxy halos, but some tendency to trace the largest structures of walls and voids in the galaxy distribution. The properties of the absorbers and galaxies in this local volume will be compared with simular measures of coherence and line properties from SPH simulations run to zero redshift. This work will be submitted for publication in 2008. K. Eriksen, A. Marble, B. Lei, C. Petry, and C. Impey are using a new sample of paired quasar lines of sight to do cosmological experiments at z = 2-3. The relation between auto-correlation of the Lyman alpha forest along a line of sight and the cross-correlation between paired lines of sight yields a constraint on Lambda once the distorions due to peculiar velocities have been accounted for, in a variant of the Alcock-Pacynski test. The velocity shear of coherence absorbers between lines of sight is sensitive to the overall matter density. The experiment also provides a fundamental test of the paradigm where large scale structure emerges from gravitational clustering over a wide rang eof scales. Spectroscopy of the relatively faint pairs required for this project is being obtained at the MMT, Keck, and Magellan telescopes. The cosmological measures will be calibrated against hydrodynamic simulations. At this point, data on 30 pairs has been acquired and a cross-correlation signal is clearly seen in almost all cases, with an amplitude that increases with decreasing angular separation. The first two paper were accepted in late 2007, and a third is in preparation. C. Impey is part of the COSMOS consortium, a large collaboration led by N. Scoville (Caltech) that received 640 orbits over HST Cycles 12 and 13 to image a two square degree region centered on an equatorial field with the ACS. This is the largest time allocation for a contiguous survey ever given with the HST. The primary science is the measurement of large scale structure, galaxy morphology and evolution in the range 1 < z < 2, weak gravitational lensing, comparisons with the huge VLT/VIMOS spectroscopic survey, and coordinated multi-wavelengths observations from radio to X-ray wavelengths. The data has been taken, fully calibrated and reduced. A full release along with ACS catalogs occurred at the January 2006 AAS Meeting in Washington, DC. Impey is co-author on 15 papers resulting from this survey that appeared in a special issue of Astrophysical Journal Supplements in 2007. C. Impey and C. Casey are using Subaru and CFHT deep multi-color imaging from the COSMOS survey to identify AGN down to I_AB = 26 using departures from the colors of the stellar locus. The technique can be calibrated by a set of 100 spectroscopically confirmed QSOs down to I_AB = 21 found from the SDSS database in this region. It can then be extended using 350 new QSO and AGN down to I_AB = 23 with spectra from the Magellan telescope; these objects were selected by X-ray emission so have no selection filter according to the optical energy distribution. These two samples will allow a full calibration of the sensitivity of the UBvriz selection as a function of redshift and SED. The technique will then be used to identify AGN with high probability to the faintest level ever attempted. Grism techniques allowed some of these objects to be confirmed at the Magellan telescope in the spring of 2007. A paper on the selection method has been accepted by Ap.J. and a second paper is in preparation. C. Impey and J. Trump, along with P. McCarthy (Carnegie), M. Elvis (CfA) and John Huchra (CfA) are carrying out a major spectroscopic survey of AGN in the 2 square degree COSMOS field. The size, depth, and extensive multi-wavelength observations of the survey allows for bolometric studies of AGN in a wide variety of environments. A first season of observing has produced spectroscopic redshifts for about 350 X-ray and radio-selected AGN targets. Spectra were obtained with the Magellan (Baade) telescope and the IMACS instrument, using the nod-and-shuffle technique. A variety of Type 1 and Type 2 AGN are identified, as well as red galaxies with no strong emission lines. The redshift yield is 72% down to I_AB = 24, but it is expected that the yield will increase as the survey continues. When the Magellan survey is complete and additional redshifts from the ESO VLT are included, we expect ~1100 AGN with redshifts over the entire COSMOS field. This will be sufficient for a clustering analysis as well as the detection of rare populations like BALs and highly obscured AGN. The first survey paper was published in 2007, a second survey paper is in preparation, as is a paper on a possible lower bound to supermassive black hole accretion rates in AGN. C. Impey and J. Gabor are using Hubble ACS images taken as part of the Cosmic Evolution Survey (COSMOS), an HST Treasury Project to map 2 square degrees of sky, to investigate host morphologies and close companions of AGNs at redshifts from z~0.2 to ~2.0. After the initial X-ray and radio selection, COSMOS team members have performed spectroscopic follow-up observations to confirm 350 AGN so far, with an expected total yield of about 1100 from ongoing observations. We use the high-resolution HST images of these AGNs to characterize their hosts with simple morphological models, including Sersic profile fits and asymmetry via Fourier-component analysis. Furthermore, each postage stamp ACS extraction is searched for nearby companion galaxies to the AGN hosts. Completion of these studies on the entire sample will allow constraints on theories in which galaxy mergers fuel AGNs. The first paper will be submitted in late spring 2008.