13A abstracts

SMARTS

The CHIRON Planet Search for Rocky Planets
M. Giguere, D. Fischer

While the occurrence of Jupiter-mass planets around nearby stars is fairly well known, there is currently a significant discrepancy between several published values for the occurrence of low-mass planets (Howard et al. 2010a, Howard et al. 2011a, Mayor et al. 2011). While the amplitude of the wobble induced in solar-type stars by orbiting very low-mass planets is below the detection capabilities of HIRES on Keck, or any other instrument available to the US community, CHIRON has demonstrated that it is capable of detecting these planets through it’s sub-m s −1 precision over long time periods. We propose to use the CHIRON spectrometer on the CTIO-1.5m to determine the occurrence of low-mass planets and the frequency of low-mass planets in multi-planet systems. Knowing the mass and period distributions of planetary systems is necessary in order to understand planet formation and test formation theories. The low-mass planets around nearby stars we aim to discover with CHIRON will also be crucial for the development of future missions to detect the atmospheres of planets orbiting nearby stars and the eventual determination of the occurrence of habitable worlds.

Astrometric and Photometric Follow-up of the La Silla-QUEST Kuiper-Belt survey 2012B and 2013A
D.Rabinowitz, S. Tourtellotte, M. Schwamb, E. Hadjiyska

We propose two observing programs. The first is to continue our astrometric and photometric follow up of the distant solar-system bodies discovered by Yale’s La Silla - QUEST survey (LSQ). LSQ is detecting several new distant objects per month and the SMARTS 1.3m is vital for charactizing their orbits and physical properties. We anticipate the discovery of several exciting new objects – the largest objects, and those with the most peculiar properties – that we will follow with SMARTS to determine their rotation state and surface composition. The second program (beginning Oct 2012) is to reobserve the rotational light curve of 2010 WG9, an unusual Kuiper Belt object with extremely high inclination discovered by LSQ that likely has entered the Kuiper Belt from the Oort Cloud. The rotation period we fit to our earlier SMARTS observations is unusually long, perhaps indicating a binary system. This needs confirmation.

The Remains of the Dwarf Galaxy Associated with Omega Centauri
R. Zinn, K. Vivas, J. Fernandez

We propose to obtain follow-up spectra of 13 RR Lyrae stars recently discovered with the QUEST camera at the 1m Schmidt telescope at the Venezuelan National Observatory. These stars lie within ∼ 10 ◦ from the center of the globular cluster ωCen, and they have the same magnitude as its horizontal branch. Thus, they are strong candidates to be material stripped from the cluster or from the disrupted galaxy associated with it. Radial velocities will allow us to confirm a physical association with the cluster and can provide constrains in the models of the destruction of ωCen by the tidal forces of the Milky Way.

WIYN

The Role of Close Companions in the Formation of Brightest Cluster Galaxies and Intracluster Light
L. O. V. Edwards , S. L. McGee (Leiden University)

Several puzzles continue to plague our understanding of the formation of Brightest Cluster Galaxies (BCGs). We will address the following ones in this proposal: 1) How are star forming BCGs, especially those outside of cool core clusters, fueled? And why has the otherwise effective quenching mechanism failed to work in these galaxies? 2) What is the age and metallicity of the accumulated stellar mass? And can these be understood simultaneously in hierarchical galaxy formation models. 3) How does the intracluster (ICL) form? Is it a natural extension of the outer envelope of BCGs? We will examine each of these questions with WIYN SparsePak IFU-like observations of a unique sample of 8 low redshift galaxy clusters. This will lead to a spectral analysis of the BCGs, their close companion galaxies, and for the first time, large samples of ICL. Ultimately, this will allow for measurements of star formation rates, stellar ages and metallicity of each component. We will directly measure the role of interactions and close companions in the build-up of the BCG and ICL,providing new and important observational constraints on models of galaxy evolution.

Searching for Milky Way Companions: pODI Follow-up of HI-Detected Dwarf Galaxy Candidates
M. Geha, J. Grcevich (AMNH), M. Putman (Columbia)

We have identified candidate Milky Way dwarf galaxies in a systematic search of the GALFA-HI Survey catalog. These candidates are compact, isolated HI gas clouds with properties similar to that of extremely low mass dwarf galaxies on the outskirts of the Milky Way. We require a stellar detection to claim a new dwarf galaxy, since there are currently no known HI-only galaxies. Based on very rough estimates, the majority of these candidates are expected between 300 kpc to 1 Mpc. Over these distances, the brightest associated stars will range in optical magnitude from r = 22 to 24.5. Thus, the majority of these candidates are below the detection limits of the Sloan Digital Sky Survey. To confirm and estimate more accurate distances, we therefore request deep broad-band (gri) imaging with the WIYN pODI camera reaching a limiting magnitude of r ∼ 25. If we do not find stars associated with these HI candidates, the pODI observations will inform our ongoing and future multi-wavelength searches for Milky Way satellites. Confirmation of a single candidate will represent the first low luminosity Milky Way satellite detected outside the SDSS and open a new era of dwarf galaxy searches.

A Complete Sample of X-Ray-Selected AGN in Stripe 82
E. Glikman, S. LaMassa, C.M. Urry

We propose to complete a census of supermassive black hole growth by analyzing ∼ 12 deg 2 of archival XMM-Newton and ∼ 7.5 deg 2 of Chandra data matched to SDSS objects in Stripe 82. The large volume accessible with this survey as well as the hard X-ray response of Chandra and XMM provide access to rare objects (e.g., high L, high z, high mass). We will use this complete sample of X-ray-selected AGN, which is least sensitive to obscuration, to advance several key science goals: We will (1) measure the bright end of the X-ray luminosity function of QSOs, which is surprisingly poorly measured in X-rays; (2) study the co-evolution of black holes and their host galaxies, using the superior imaging available in this area; (3) obtain a full, multiwavelength census of X-ray bright AGN, using the extensive multiwavelength data in this area.

A Study of Isolated Interacting Dwarf Galaxy Pairs: Bridges and Tails
N.Kallivayalil, M. Geha, G. Besla (Columbia)

We request WIYN pODI Hα imaging for a sample of 20 isolated interacting dwarf galaxy pairs. These pairs were identified in the NASA-Sloan database and selected to be isolated analogs of LMC-SMC systems. Our goal is to quantify star formation rates in the individual galaxies and intervening tidal bridges as a function of pair separation and mass ratio. It is likely that the merging process between dwarf galaxies is quantitatively different as compared to more massive counterparts. In particular, the absence of quenched dwarf galaxies in the field suggests that the product of dwarf-dwarf mergers are not red and dead ellipticals. We thus hypothesize that the earlier stages of the dwarf merger sequence also differ; however, tidally induced star formation in dwarf galaxy pairs has not been studied systematically in any survey to date. Deep WIYN pODI imaging in Hα, r, and i will allow us to quantify the rate of star formation triggered in the interacting galaxies themselves and any tidally induced structures, bridges and tails, surrounding them. Bridges between dwarf galaxies will be particularly metal poor and subject to strong shocks - such structures represent physical environments where star formation is poorly understood. Given the ubiquity of low metallicity galaxies at high z, understanding how star formation proceeds in such regimes is critical to our understanding of the chemical evolution of high z galaxies and the cosmic star formation rate.

Systematic Characterization of Exoplanetary Atmospheres
N. Madhusudhan, J. M. Brewer, D. Fischer, J. Wang, C. Schwab, A. Mandell (NASA-GSFC), C. Jurgenson

Detailed characterization of extrasolar planets is one of the major frontiers of astronomy today. At the leading edge of this endeavor is the detection and characterization of exoplanetary atmospheres, whose chemical compositions and thermal profiles provide insights into their atmospheric processes, interior compositions, and formation conditions. In this program, we propose to conduct a systematic mini-survey of exoplanetary atmospheres using ground-based near-infrared photometric observations of thermal emission from four transiting hot Jupiters with different levels of stellar irradiation. By combining our proposed ground-based observations with existing Spitzer data at longer wavelengths, we plan to simultaneously infer the atmospheric thermal structures and compositions of the planets in our sample. The correlations between the inferred atmospheric properties and the incident irradiation levels will help constrain existing classification schemes of hot Jupiter atmospheres. Our effort will also demonstrate the feasibility of WIYN-WHIRC for high-precision infrared photometry of exoplanetary atmospheres.

Rayleigh Scattering in Exoplanet Atmospheres
S. Redfield, A. Jensen (Wesleyan), D. Fischer, N. Madhusudhan, M. Schwamb, W. Cochran (U.T.-Austin), Michael Endl (U.T.-Austin), T. Barman (Lowell), J. Lee (Oxford)

The vast majority of exoplanet atmospheric characterization has been of gas giants in the form of narrow atomic features in high resolution optical and ultraviolet spectra (e.g., Na I, Hα) and from broad molecular features in narrowband infrared photometry (e.g., CO, CO2, H2O). Super-Earths (M < 10M⊕) are of particular interest not only because there is no solar system analog, but also because the atmospheric transition from low molecular weight (giant-like) to high molecular weight (terrestrial-like) occurs in this regime. Unfortunately, infrared observations can be very similar for these two scenarios, and alone, are unable to differentiate between very different atmospheric structures (Benneke & Seager 2012). Observations of Rayleigh scattering in the optical are required to make a unique determination of atmospheric structure. We propose a pilot program to take advantage of the multi-object capability of Hydra on WIYN to make the first ground-based detection of a complete optical Rayleigh scattering spectrum f an exoplanetary atmosphere. We predict that we could detect the only other spectral measurement of Rayleigh scattering spectrum to-date, that of HD189733b observed with HST, with a significance of ∼7σ and smaller, Neptune-mass planets at >3σ with a single observed transit.

Quantifying the Minor Merger History of Bulgeless Galaxies Hosting Growing Supermassive Black Holes
C.M. Urry, B.D. Simmons, E. Glikman, C. Lintott (Oxford), S. Kaviraj (Oxford), K. Schawinski (ETH Zurich), A. Merritt

We request 7 nights of WIYN time to carry out a multiwavelength study of bulgeless galaxies hosting AGN, including near-infrared images to place the strictest possible limits on bulge contributions to these galaxies, and deep optical images of their extended halos. Combined with recent simulations, the deep observations will allow us to quantify the maximum mass of satellite galaxies that could have been accreted by these disk galaxies during their formation histories. Detecting the long-lived tidal streams of satellite galaxies at ∼ 28 mag/arcsec 2 requires long integration times but will enable us to observationally answer one of the fundamental questions of galaxy evolution: what mass of minor merger is possible without creating a bulge? Additionally, because these galaxies host actively growing black holes, we will also quantitatively probe the connection between minor mergers and black hole growth. Importantly, a non-detection of satellite streams would be just as scientifically fruitful, allowing us to dfinitively attribute the observed black hole growth to merger-free processes, which are ordinarily very difficult to disentangle from merger-driven black hole growth.

Diffraction-Limited Imaging with DSSI: Surveying Hipparcos Binaries and Vetting Candidate Exoplanet Host Stars
W. van Altena, E. Horch, S. Howell, D. Fischer

We propose two complementary projects best handled in the same run with the DSSI speckle camera, a visitor instrument currently at WIYN. The first project is a continuation of our effort to provide high-precision relative astrometry and differential photometry of binary stars. The main goal is to characterize a volume-limited sample of binaries within 250 pc of the Sun. With the full data set, it will be possible to make a major contribution to the main-sequence mass-luminosity relation especially for low-mass and metal-poor stars, as well as to conduct dozens of very sensitive tests of the details of stellar evolution models and to understand the statistics of thin and thick disk binaries. The latter is important in learning how to use binaries as probes of galactic structure and evolution. The second project is to obtain diffraction-limited images of candidate exoplanet host stars as a part of ground based follow-up for Kepler and including targets identified through the Planethunters citizen science project. Th photometric signal of an apparent planetary transit can be mimicked by e.g. a background eclipsing binary star very close to the Kepler target. With the high resolution that the DSSI camera provides, a substantial section of parameter space for this type of false positive can be ruled out. If a star has an exoplanet and has a close companion star, then the light due to the second star must be known before the light curve of the transit can be properly interpreted. DSSI can do this job as well with its proven photometric precision.

High Resolution Imaging of Globular Cluster Candidates
R. Zinn, G. di Tullio Zinn

We propose to observe with WHIRC candidate globular clusters that we have identified in the remote halo of M31 at (projected distances ≥ 100 kpc) and in areas of the sky that probe the extreme halo of the Milky Way (MW) and fields of the Local Group. If these objects are star clusters, they should be resolved by the superior resolution and depth of WHIRC over the SDSS. Photometry of the brightest stars in these objects and in a few of the new M31 clusters that we have discovered recently will be used to constrain their distances. This investigation should provide more information of the differences between the star clusters in the extreme halos of M31 and the MW, which are unexpected in the “accretion paradigm”, the formation of the stellar halos of galaxies by the accretion and destruction of dwarf galaxies.

Keck

Yale Exoplanet Search
D. Fischer, M. Giguere, J. Brewer, J. Moriarity, T. Boyajian

In the past year, the exoplanets from Kepler and Doppler surveys have demonstrated that SuperEarth and Neptune (SEN) mass planets are common: at least 25% of stars have low mass planetswith orbital periods less than 50d. Late type stars are ideal for the detection of these exoplanets:stellar noise is a minimum and the low stellar mass results in a larger reflex velocity. We havedefined a subset of 30 bright stars from the M2K program that already have a heritage of ∼16observations. The formal measurement precision is about 1.4 m s−1, and the mean velocity rms ofthis sample is 9 m s−1, making these prime targets for a search for short-period SEN planets.We are also continuing to follow up on a sample of metal-rich stars where we continue to detectgas giant planets in orbits from a few days to several years.

Low-mass Protostars in the Massive Filament G34.42+0024: When and Where is the IMF Established?
J. B. Foster, H. Arce, S. Offner, M. Kassis (Keck)

We propose to characterize the distribution of low-mass protostars in G34.43+00.24, a very young and nearby massive star-forming region. The initial mass function (IMF) of stars, which is important for understanding topics as varied as planetary disk formation to galactic evolution, is set in regions which are forming massive stars, but we do not know the details of this process. Do low-mass stars form co-evally with high-mass stars? How are low-mass protostars clustered around massive protostars and organized with respect to the massive clumps within a filament? From pilot data we know that our proposed observations will have sufficient depth and resolution to find lowmass stars within G34.43+00.24 based on their colors and by resolving the K-band bright outflows from young low-mass stars. Our observations will complement additional data on this source which is currently being observed from the submillimeter to the X-ray, and stands poised to become an examplar of the very early stages of massive star formation w hin a filament.

Chemical Evolution in the Oldest Known Galaxies
M. Geha, L. Vargas, E. Kirby (UC Irvine), J. Simon (Carnegie), T. Brown (STScI)

We propose Keck/DEIMOS observations of three Milky Way ultra-faint dwarf (UFD) galaxies in order to discern cosmologically-driven synchronization of their star formation histories. Hierarchical LCDM models predict that extremely low mass galaxies form the bulk of their stars before the epoch of reionization. We have recently obtained HST photometry for six UFDs and confirm that these objects have exclusively old ages (13.5 ± 0.5 Gyr). While this demonstrates that the UFDs are the oldest known galaxies, our age resolution is not sufficient to test timescales relevant to reionization which require +/- 200 Myr. Because the magnitude and color of the strongest age indicator, the main sequence turnoff, depends on metallicity, characterizing the distribution of metallicities in these objects is critical. Yet most of these UFDs have only ∼ 10 stars with measured metallicities. The lack of a larger metallicity sample represents the dominant statistical uncertainty on the derived ages of the UFD galaxies. We therefore req est Keck DEIMOS observations to significantly increase the number of stars with measured metallicities. These observations will allow us to test whether reionization is responsible for suppressing star formation in the low luminosity galaxies.

Thermal Spectrum of the hot Jupiter KOI-13.01
N. Madhusudhan, J. M. Brewer, D. Fischer, J. Wang, C. Jurgenson. C. Schwab, D. Anderson (WASP), P. Kabath (ESO)

One of the major frontiers of exoplanetary science today concerns the characterization of exoplanetary atmospheres. Recent advancements in observational techniques hold new promise for ground-based spectroscopy of exoplanetary atmospheres. Although several successful observations of thermal emission from transiting exoplanets have been reported using broad-band photometry, ground-based spectroscopy has had only limited success thus far. In the present proposal, we propose to use a fortuitous combination of a promising technique and a new particularly suitable target which will allow us to make the first high confidence detection of a high-resolution thermal spectrum from an exoplanet from ground. We propose to use an Integral Field Spectrograph (IFS) to recover the emission spectrum of a planet in the multiple star system KOI-13, which benefits relative to previous attempts by providing a very close comparison source for tellurians calibration and by avoiding variable slit losses and high background associated wh long-slit spectrographs. Besides being the first high resolution thermal spectrum of an exoplanet, the proposed observation will combine with existing data obtained with the Kepler space telescope to constrain the molecular composition, temperature profile, day-night heat-redistribution efficiency, and the albedo of the unique hot Jupiter KOI-13.01.

Adaptive Optics Imaging of Transiting Planet Candidate Host Stars
M. Schwamb, M. Giguere, J. Crepp (U. Notre Dame)

NASA’s Kepler mission is monitoring nearly 160,000 stars for the signatures of transiting exoplanets. As the planet passes in front of its parent star it blocks out a portion of the star’s light. In an ideal case the depth of the transit is equal to the squared ratio of the radius of the planet to the star’s radius. But if there is any additional light from a neighboring star in the photometric aperture this will dilute the transit making it shallower. Without knowledge of the contaminating stars, one is unable to accurately assess the planet properties, and will estimate a smaller radius for the planet. Kepler has relatively large pixels (with a pixel scale of 4 !! per pixel) and a typical 6 !! radius photometric aperture used to generate the Kepler light curves. Using Natural Guide Star Adaptive Optics with NIRC2, one can achieve 10 miliacrsecond per pixel resolution revealing close companions within 5 !! of the planet candidate host star. Stellar companions found closer than 1 !! are likely to be bound in wide binary with the host star. We propose to follow-up on Planet Hunters planet candidates to search for close contaminator stellar companions in order to better constrain the properties of the planet and assess the likelihood the candidate is false positive.

The quenching of star formation in truly interacting pairs at high redshift
R. Skelton, R. Bezanson, I. Momcheva, E. Nelson, P. van Dokkum

One of the key questions in galaxy formation is how the striking bimodality of galaxy properties at low redshifts emerged and what role mass and environment play in the quenching of star formation. To address this, we need accurate measurements of star formation rates and environment. We have identified pairs of galaxies that are close in both projected distance and redshift in the 3D-HST survey at z ∼ 1, some of which are in overdensities in redshift space. While mergers are likely to be more common in group-scale environments, the likelihood of finding a projected pair also increases. 3D-HST provides excellent information on the star forming properties of galaxies and good enough redshifts to select pair candidates, but its ∼ 1000 km s −1 resolution is not sufficient to tell the difference. A high fraction of the companions of massive galaxies in this sample have very low levels of star formation, suggesting that they are quenched in tidal interactions, but it may be the larger scale environment rather than the ompanion that has the strongest influence. Using 2 nights with Keck/DEIMOS we will obtain 300 − 400 spectroscopic redshifts that will allow us to confirm whether pairs of galaxies identified in 3DHST are truly interacting, and what kind of environments they are in. The combination of precise spectroscopic redshifts and spectral information from DEIMOS with spatially resolved star formation information from 3D-HST will be a powerful tool to explore what quenches star formation at z ∼ 1.

Faster, Cheaper, Better: Tracing the Build-up of Galaxies at Fixed Number Density
P. van Dokkum, J. Leja, I. Momcheva, E. Nelson, R. Skelton

The redshift range 1 < z < 3 is marked by great diversity and change, and is key to understanding how present-day elliptical and spiral galaxies were formed. New multi-object near-IR spectrographs on Keck and the VLT are now opening up this redshift range for systematic study. Several large surveys will be done over the coming years, using dozens of nights to measure star formation rates, metallicities, kinematics and the dust content of hundreds of galaxies from rest-frame optical emission lines. Here we propose a relatively short MOSFIRE program to achieve several of the key science goals of these large surveys. This is possible thanks to two key differences with respect to competing surveys. First, we select galaxies at a constant number density at all redshifts, thus tracing the same galaxy population through cosmic time. This is a much more efficient selection than observing all galaxies down to some mass or star formation limit, as other surveys are doing. Second, we use our 250 orbit 3D-HST Treasury progr m to pre-select galaxies with detectable emission lines away from atmospheric absorption and emission. In only 3 nights we expect to measure Hα, Hβ, and [O iii] for ≈ 20 galaxies at hzi = 0.8, ≈ 15 galaxies at hzi = 1.5, and ≈ 20 galaxies at hzi = 2.3, all selected to have the same cumulative number density of 2 × 10 −4 Mpc −3 . This allows us to determine the evolution of the mean star formation rate, dust content, metallicity, and line width of galaxies. Combined with our 3D-HST emission maps and morphologies this will constitute the first self-consistent measurement of the build-up of galaxies during the peak of the cosmic star formation history.