12B abstracts

SMARTS

SMARTS Observations of Fermi/LAT Monitored Blazars
C.D. Bailyn, C.M. Urry, M. Buxton, E. Bonning, R. Chatterjee, J. Isler

We propose to extend our ongoing program of SMARTS studies of blazars observed by Fermi/LAT. The Yale SMARTS team provides optical/IR photometry similar in cadence, duration, precision and homogeneity to the data provided by Fermi in GeV energies, as well as regular, bi-monthly spectroscopy of the brighter sources. In combination, these data are able to constrain both characteristic peaks of blazar spectral energy distributions. In addition, the optical emission lines allow unprecedented constraint on the disk and jet emission in these sources. Intra-night optical/IR monitoring can also help to constrain the size of the γ-emitting region. This data set is unique in its extent, duration and utility.

SMARTS Observations of X-ray Binaries
C.D. Bailyn, M. Buxton, R. Chatterjee, R. MacDonald, J. Orosz, J. McClintock, R. Remillard

We propose to continue our long-term campaign to monitor X-ray binaries with the SMARTS telescopes. The X-ray binaries we study are systems in which a compact object is accreting material from a Roche-lobe-filling secondary star; they can exist in any of several X-ray states, including quiescence and several types of outburst. Our monitoring program studies these objects while in X-ray quiescence, in order to learn more about their optical properties, binary parameters, and accretion flows. In addition to providing long-time-baseline light curves for a dozen objects, data from this project have shown that X-ray quiescent systems are often not completely stable and predictable—they can exhibit different optical states, with “active” being both brighter and more variable than “passive.” Our data have also shown that there are often optical precursors to X-ray outbursts, and that in some systems one can determine the X-ray state of the object simply by examining the optical and IR data. None of these discoveries would be possible with a one-time observing run. This long-term program has also provided data for many student and postdoc projects, including at least one undergraduate senior project a year for the past several years, and one ongoing PhD thesis.

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 overlong 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
D.Rabinowitz, S. Tourtellotte, M. Schwamb, E. Hadjiyska

We propose to continue our astrometric and photometric follow-up of the distant solar-system bodies discovered by Yale’s La Silla - QUEST survey (LSQ). Studying the nature of these relic planetesimals constrains their composition, and also the formation and evolution of the solar system. LSQ is detecting several new distant objects per month. Our previous discovery of an unusually high-inclination body (2010 WG09) has led to a new constraint on the size of the Oort cloud and the dynamical pathways that bring these very distant bodies into the Kuiper Belt. Our recent SMARTS observations of the distant binary object, Sila-Nunam (1997 CS29), serendipitously led to a detection of a mutual eclipse and orbital period of the two objects. In combination with HST and Spitzer observations, our observations characterise the diameter, albedo, and density of the binary pair. We anticipate the discovery of several more 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. We are also combining these results with visible and near-IR observations that we are making with the NTT at La Silla and the VLT at Paranal.

WIYN

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

We propose to complete a census of supermassive black hole growth by analyzing ~ 12 deg2 of archival XMM-Newton data matched to SDSS objects in Stripe 82. The large volume accessible with this survey as well as the hard X-ray response of XMM-Newton provides 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, complementing deep pencil-beam surveys like GOODS, CANDELS and COSMOS. .

Dwarf Satellites Around Milky Way-like Galaxies
E. Tollerud, M. Geha, A. Bonaca

The Milky Way (MW) galaxy is host to two dozen dwarf galaxy satellites. However, the brightest of these satellites and their properties do not fully agree with predictions from galaxy formation models. In particular, models suggest that there should be a factor of three more satellites brighter than the Fornax dwarf galaxy (eight magnitudes fainter than the MW, or ∆m = 8) than is known. While it is possible that model predictions are incorrect, an equally plausible solution is that the Milky Way’s satellite population is not representative of a typical MW-mass galaxy. No MW analog systems currently exist with known satellite properties down to ∆m = 8, with the exception of M31 which is likely twice as massive as the MW. This proposal aims to measure the luminosity function of satellites down to the scale of the Fornax dwarf for ten MW-analogs. These data will lay the ground work for follow-up observations with the Keck telescope to measure the satellite mass function. Photometrically, satellite galaxies cannot be distinguished from the much larger population of background galaxies at higher redshift. We therefore request 7 nights with WIYN/HYDRA to spectroscopically identify satellites around 10 MW-like host galaxies.

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. The 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..

Keck

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

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 planets with 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 have defined a subset of 30 bright stars from the M2K program that already have a heritage of ~10 observations. The formal measurement precision is about 1.4 m s−1, and the mean velocity rms of this sample is 9 m s−1, making these prime targets for a search for short-period SEN planets. We are also following planet candidates from a sample of metal-rich stars and using time to investigate planet candidates discovered by users on PlanetHunters.com.

Precision Abundances of M31 dSph Satellites
M. Geha, E. Tollerud, L. Vargas

The dwarf spheroidal (dSph) satellites of the Milky Way are the faintest known galaxies, but nevertheless show a clear trend between their total luminosity and average metallicity. Such a relation provides strong constraints on formation scenarios for these galaxies, in particular implying that their faint luminosities are not due to extreme tidal stripping of larger systems. The lack of precision abundances for dSphs outside the Milky Way prevents broad applicability of such constraints. Recent observations of the environs of M31 reveal a similar population of dSphs. We therefore propose three nights of DEIMOS spectroscopy to obtain precision abundances for
individual stars in six M31 dSphs. This is sufficient to test if the Milky Way luminosity-metallicity relation holds for M31 dSphs, the first measurement of such a relation for a single host’s satellite system outside the Milky Way. This dataset will also provide significant ancillary science, improving mass estimates for these objects as well as providing the first-ever precision abundance of a M31 halo star.

Probing Quasar/Galaxy Co-Evolution: Integral-Field Spectroscopy of Dust Obscured Quasars
E. Glikman, C.M. Urry, B. Simmons, K. Schawinski

We propose to obtain high angular resolution, spatially-resolved spectroscopy of moderately dust-obscured quasars and their strongly interacting hosts with the OSIRIS integral field spectrograph combined with Laser Guide-Star Adaptive Optics. We have identified a large sample of red quasars by matching the radio and near-infrared surveys and spectroscopically following up very red objects. Detailed study of this population reveals that red quasars are the most intrinsically luminous objects in the Universe at all redshifts, and appear to represent a transitional phase in the mergerdriven black hole growth scenario. The observations proposed here will probe the morphology and kinematics of the ionized gas, extended star formation, and dust distribution in these systems, as well as the potential for dual, pre-merger quasars. These observations will shed light on the triggering and fueling mechanisms for the buried, yet emerging quasars, their feedback processes,and the implications for galaxy/SMBH co-formation and co-evolution.

3D-HST+NewHα: Accurate Measurements of Metallicities, Dust, and Active Nuclei in Star-Forming Galaxies at z ~ 2
I. Momcheva, P. van Dokkum, E. Nelson, J. Leja, J. Lee, C. Ly, D. Dale, M. Ouchi

We propose to study the physical properties of a large sample of star-forming galaxies at z ~ 2, a time when the structural components of today’s galaxies were assembled. Using MOSFIRE we will acquire NIR spectroscopy of the full suite of optical emission line – [OII]λ3727 (in the J band), Hβ, [OIII]λ4959 and [OIII]λ5007 (in the H band), as well as Hα and [NII]λλ6548,84 (in the K band) – for a sample of 100 normal star forming galaxies at z = 2.2. From these rest-frame optical spectra we will measure the star formation rates, dust content, metallicities, and AGN presence. This endeavor has become possible thanks to the availability of to our NewHα + 3D-HST surveys, which are uniquely suited for efficient target selection. We will target well-characterized galaxies with know redshifts thereby selecting an optimal and ”risk-free” sample. The overarching goal is to determine when and how the stars in present-day galaxies were formed. In practice, we will determine the physical conditions in star forming galaxies and correlate them with their structure, stellar mass, and other parameters. We expect this to be the first of a major survey effort at Yale to characterize the physical properties of galaxies during a time when most of the stellar mass and most of the black hole mass in the Universe were assembled. We stress, that this first sample of 100 will already be the largest of its kind, and will lead to several papers. The project is firmly centered at Yale.


Does the IMF vary with velocity dispersion?
P. van Dokkum, C. Conroy

Over the past two years several studies, including our own, have suggested that the initial mass function (IMF) varies systematically with a galaxy’s velocity dispersion σ: galaxies with σ ~ 150 km/s have IMFs similar to the Milky Way, whereas galaxies with σ ~ 300 km/s appear to have “bottom-heavy” IMFs with a very large number of low mass stars. This result is hotly debated, as it would have significant implications for many areas of astrophysics. Here we propose to use NIRSPEC to test whether the IMF does indeed vary with velocity dispersion.