R. Cutri

California Institute of Technology, Pasadena, California, United States

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Publications (448)675.75 Total impact

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    ABSTRACT: The Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) mission observed comet C/2013 A1 (Siding Spring) three times at 3.4 {\mu}m and 4.6 {\mu}m as the comet approached Mars in 2014. The comet is an extremely interesting target since its close approach to Mars in late 2014 will be observed by various spacecraft in-situ. The observations were taken in 2014 Jan., Jul. and Sep. when the comet was at heliocentric distances of 3.82 AU, 1.88 AU, and 1.48 AU. The level of activity increased significantly between the Jan. and Jul. visits but then decreased by the time of the observations in Sep., approximately 4 weeks prior to its close approach to Mars. In this work we calculate Af\r{ho} values, and CO/CO2 production rates.
    12/2014;
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    ABSTRACT: We present 20 WISE-selected galaxies with bolometric luminosities L_bol > 10^14 L_sun, including five with infrared luminosities L_IR = L(rest 8-1000 micron) > 10^14 L_sun. These "extremely luminous infrared galaxies," or ELIRGs, were discovered using the "W1W2-dropout" selection criteria (Eisenhardt et al. 2012) which requires marginal or non-detections at 3.4 and 4.6 micron (W1 and W2, respectively) but strong detections at 12 and 22 micron in the WISE survey. Their spectral energy distributions are dominated by emission at rest-frame 4-10 micron, suggesting that hot dust with T_d ~ 450K is responsible for the high luminosities. These galaxies are likely powered by highly obscured AGNs, and there is no evidence suggesting these systems are beamed or lensed. We compare this WISE-selected sample with 116 optically selected quasars that reach the same L_bol level, corresponding to the most luminous unobscured quasars in the literature. We find that the rest-frame 5.8 and 7.8 micron luminosities of the WISE-selected ELIRGs can be 30%-80% higher than that of the unobscured quasars. Assuming Eddington-limited accretion, the existence of AGNs with L_bol > 10^14 L_sun at z > 3 places strong constraints on the supermassive black hole growth history, suggesting that these supermassive black holes are born with large mass, or have very rapid mass assembly, possibly by chaotic accretion.
    10/2014;
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    ABSTRACT: NASA's Wide-field Infrared Survey Explorer (WISE) spacecraft has been brought out of hibernation and has resumed surveying the sky at 3.4 and 4.6 um. The scientific objectives of the NEOWISE reactivation mission are to detect, track, and characterize near-Earth asteroids and comets. The search for minor planets resumed on December 23, 2013, and the first new near-Earth object (NEO) was discovered six days later. As an infrared survey, NEOWISE detects asteroids based on their thermal emission and is equally sensitive to high and low albedo objects; consequently, NEOWISE-discovered NEOs tend to be large and dark. Over the course of its three-year mission, NEOWISE will determine radiometrically-derived diameters and albedos for approximately 2000 NEOs and tens of thousands of Main Belt asteroids. The 32 months of hibernation have had no significant effect on the mission's performance. Image quality, sensitivity, photometric and astrometric accuracy, completeness, and the rate of minor planet detections are all essentially unchanged from the prime mission's post-cryogenic phase.
    The Astrophysical Journal 06/2014; 792(1). · 6.73 Impact Factor
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    ABSTRACT: We present SCUBA-2 850um submillimetre (submm) observations of the fields of 10 dusty, luminous galaxies at z ~ 1.7 - 4.6, detected at 12um and/or 22um by the WISE all-sky survey, but faint or undetected at 3.4um and 4.6um; dubbed hot, dust-obscured galaxies (Hot DOGs). The six detected targets all have total infrared luminosities greater than 10^13 L_sun, with one greater than 10^14 L_sun. Their spectral energy distributions (SEDs) are very blue from mid-infrared to submm wavelengths and not well fitted by standard AGN SED templates, without adding extra dust extinction to fit the WISE 3.4um and 4.6um data. The SCUBA-2 850um observations confirm that the Hot DOGs have less cold and/or more warm dust emission than standard AGN templates, and limit an underlying extended spiral or ULIRG-type galaxy to contribute less than about 2% or 55% of the typical total Hot DOG IR luminosity, respectively. The two most distant and luminous targets have similar observed submm to mid-infrared ratios to the rest, and thus appear to have even hotter SEDs. The number of serendipitous submm galaxies (SMGs) detected in the 1.5-arcmin-radius SCUBA-2 850um maps indicates there is a significant over-density of serendipitous sources around Hot DOGs. These submm observations confirm that the WISE-selected ultra-luminous galaxies have very blue mid-infrared to submm SEDs, suggesting that they contain very powerful AGN, and are apparently located in unusual arcmin-scale overdensities of very luminous dusty galaxies.
    Monthly Notices of the Royal Astronomical Society 06/2014; 443(1). · 5.52 Impact Factor
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    ABSTRACT: The Wide-field Infrared Survey Explorer (WISE) spacecraft has been reactivated as NEOWISE-R to characterize and search for Near Earth Objects. The brown dwarf WISE J085510.83-071442.5 has now been reobserved by NEOWISE-R, and we confirm the results of Luhman (2014b), who found a very low effective temperature, a very high proper motion, and a large parallax. The large proper motion has separated the brown dwarf from the background sources that influenced the 2010 WISE data, allowing a measurement of a very red WISE color of W1-W2 > 3.9. A re-analysis of the 2010 WISE astrometry using only the W2 band, combined with the new NEOWISE-R 2014 position, gives an improved parallax of 448 +/- 32 mas and proper motion of 8.072 +/- 0.026 arcsec/yr. These are all consistent with Luhman (2014b).
    The Astronomical Journal 05/2014; 148(5). · 4.97 Impact Factor
  • Article: 2014 HJ129
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    ABSTRACT: Abstract available on the publisher website.
    03/2014;
  • Article: 2014 HQ124
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    ABSTRACT: Abstract available on the publisher website.
    03/2014;
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    ABSTRACT: The NEOWISE project has recently resumed its survey for asteroids and comets at 3.4 and 4.6 µm.
    02/2014;
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    ABSTRACT: The AllWISE processing pipeline has measured motions for all objects detected on WISE images taken between 2010 January and 2011 February. In this paper, we discuss new capabilities made to the software pipeline in order to make motion measurements possible, and we characterize the resulting data products for use by future researchers. Using a stringent set of selection criteria, we find 22,445 objects that have significant AllWISE motions, of which 3,525 have motions that can be independently confirmed from earlier 2MASS images yet lack any published motions in SIMBAD. Another 58 sources lack 2MASS counterparts and are presented as motion candidates only. Limited spectroscopic follow-up of this list has already revealed eight new L subdwarfs. These may provide the first hints of a "subdwarf gap" at mid-L types that would indicate the break between the stellar and substellar populations at low metallicities (i.e., old ages). Another object in the motion list -- WISEA J154045.67-510139.3 -- is a bright (J ~ 9 mag) object of type M6; both the spectrophotometric distance and a crude preliminary parallax place it ~6 pc from the Sun. We also compare our list of motion objects to the recently published list of 762 WISE motion objects from Luhman (2014). While these first large motion studies with WISE data have been very successful in revealing previously overlooked nearby dwarfs, both studies missed objects that the other found, demonstrating that many other nearby objects likely await discovery in the AllWISE data products.
    The Astrophysical Journal 02/2014; 783(2). · 6.73 Impact Factor
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    ABSTRACT: We describe a methodology to classify periodic variable stars identified in the Wide-field Infrared Survey Explorer (WISE) full-mission single-exposure Source Database. This will assist in the future construction of a WISE periodic-Variable Source Database that assigns variables to specific science classes as constrained by the WISE observing cadence with statistically meaningful classification probabilities. We have analyzed the WISE light curves of 8273 variable stars identified in previous optical variability surveys (MACHO, GCVS, and ASAS) and show that Fourier decomposition techniques can be extended into the mid-IR to assist with their classification. Combined with other periodic light-curve features, this sample is then used to train a machine-learned classifier based on the random forest (RF) method. Consistent with previous classification studies of variable stars in general, the RF machine-learned classifier is superior to other methods in terms of accuracy, robustness against outliers, and relative immunity to features that carry little or redundant class information. For the three most common classes identified by WISE: Algols, RR Lyrae, and W Ursae Majoris type variables, we obtain classification efficiencies of 80.7%, 82.7%, and 84.5% respectively using cross-validation analyses, with 95% confidence intervals of approximately +/-2%. These accuracies are achieved at purity (or reliability) levels of 88.5%, 96.2%, and 87.8% respectively, similar to that achieved in previous automated classification studies of periodic variable stars.
    The Astronomical Journal 02/2014; 148(1). · 4.97 Impact Factor
  • 01/2014; 782(1).
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    ABSTRACT: Abstract available on the publisher website.
    01/2014;
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    ABSTRACT: The solar system science component of NASA’s Wide-field Infrared Survey Explorer (WISE), known as NEOWISE, extracted detections of more than 158,000 asteroids and comets, including 34,000 new discoveries. These objects were detected through a search algorithm that actively rejected inertially fixed sources such as stars and galaxies and selected candidate moving objects through the construction of position-time pairs known as tracklets. A minimum of five detections were required in order to construct a tracklet; this system enabled the discovery of new minor planets as well as detection of previously known objects. However, many more asteroids are potentially recoverable in the NEOWISE data, such as objects that failed to appear in five or more images. Stacking of objects with well-known ephemerides at the observational epoch has allowed for the recovery of many objects that fell below the single-frame detection threshold. Additional objects were recovered by searching the NEOWISE source lists for objects that appeared fewer than five times in single frames. We present the results of a pilot study that has allowed for the recovery of minor planets from the NEOWISE data using both techniques, resulting in the derivation of diameters and albedos for the sample. This pilot study will be extended to the entire catalog of known minor planets by the NEOWISE project in the near future.
    01/2014;
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    ABSTRACT: The extragalactic background light (EBL) beyond the cosmic microwave background (CMB) contains valuable information about the star formation history of the universe. The near- to mid-infrared background measurements (roughly 2—5 µm), with uncertainties in the contribution from the first stars, the accuracy of zodiacal light subtraction, and upper limits based on absorption of TeV gamma rays from blazar spectra that are lower than some measurements of the amount of light contributed by galaxies. Using WISE, we measured the 2.4 µm luminosity function of galaxies out to z = 1 and, extrapolating to low luminosity, used it to calculate the contribution of galaxies with z ≤ 1 to the 3.4 µm EBL. This marks an improvement over previous efforts to measure this contribution that relied on extrapolating flux counts because it relies on the more physically motivated luminosity function. The luminosity function is also improved over previous efforts in this wavelength range by both improved sensitivity and large N statistics from utilizing large public spectroscopic redshift surveys.
    01/2014;
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    ABSTRACT: NASA’s Wide-field Infrared Survey Explorer surveyed the entire sky in four infrared wavelengths (3.4, 4.6, 12 and 22 microns) over the course of one year. The mission’s long wavelength infrared channels were cooled by solid hydrogen; after its depletion, the mission continued using the two shortest wavelengths. Following completion of its one year survey, the mission was placed into hibernation. NASA has recently enabled the restart of the mission to discover, detect and characterize near-Earth objects (NEOs) using the 3.4 and 4.6 micron channels. With these wavelengths, it is possible to derive radiometric effective spherical diameters for NEOs with ~25% accuracy. In the process of surveying for NEOs over three years, NEOWISE will cover the sky multiple times, enabling a wide range of scientific investigations.
    01/2014;
  • Article: 2013 YP139
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    ABSTRACT: Abstract available on the publisher website.
    12/2013;
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    ABSTRACT: On behalf of the WISE Science team, we present the discovery of a class of distant dust-enshrouded galaxies with extremely high luminosity. These galaxies are selected to have extreme red colors in the mid-IR using NASA's Wide-field Infrared Survey Explorer (WISE). They are faint in the optical and near-IR, predominantly at z=2-4, and with IR luminosity > $10^{13}\, L_{Sun}$, making them Hyper-Luminous Infrared Galaxies (HyLIRGs). SEDs incorporating the WISE, Spitzer, and Herschel PACS and SPIRE photometry indicate hot dust dominates the bolometric luminosity, presumably powered by AGN. Preliminary multi-wavelength follow-up suggests that they are different from normal populations in the local M-sigma relation. Their low source density implies that these objects are either intrinsically rare, or a short-lived phase in a more numerous population. If the latter is the case, these hot, dust-enshrouded galaxies may be an early stage in the interplay between AGN and galaxies.
    11/2013;
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    ABSTRACT: Only a very small fraction of the asteroid population at size scales comparable to the object that exploded over Chelyabinsk, Russia has been discovered to date, and physical properties are poorly characterized. We present previously unreported detections of 106 close approaching near-Earth objects (NEOs) by the Wide-field Infrared Survey Explorer mission's NEOWISE project. These infrared observations constrain physical properties such as diameter and albedo for these objects, many of which are found to be smaller than 100 m. Because these objects are intrinsically faint, they were detected by WISE during very close approaches to the Earth, often at large apparent on-sky velocities. We observe a trend of increasing albedo with decreasing size, but as this sample of NEOs was discovered by visible light surveys, it is likely that selection biases against finding small, dark NEOs influence this finding.
    The Astrophysical Journal 10/2013; 784(2). · 6.73 Impact Factor
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    ABSTRACT: We present WISE All-Sky mid-infrared (IR) survey detections of 55% (17/31) of the known QSOs at z>6 from a range of surveys: the SDSS, the CFHT-LS, FIRST, Spitzer and UKIDSS. The WISE catalog thus provides a substantial increase in the quantity of IR data available for these sources: 17 are detected in the WISE W1 (3.4-micron) band, 16 in W2 (4.6-micron), 3 in W3 (12-micron) and 0 in W4 (22-micron). This is particularly important with Spitzer in its warm-mission phase and no faint follow-up capability at wavelengths longwards of 5 microns until the launch of JWST. WISE thus provides a useful tool for understanding QSOs found in forthcoming large-area optical/IR sky surveys, using PanSTARRS, SkyMapper, VISTA, DES and LSST. The rest-UV properties of the WISE-detected and the WISE-non-detected samples differ: the detections have brighter i/z-band magnitudes and redder rest-UV colors. This suggests that a more aggressive hunt for very-high-redshift QSOs, by combining WISE W1 and W2 data with red observed optical colors could be effective at least for a subset of dusty candidate QSOs. Stacking the WISE images of the WISE-non-detected QSOs indicates that they are on average significantly fainter than the WISE-detected examples, and are thus not narrowly missing detection in the WISE catalog. The WISE-catalog detection of three of our sample in the W3 band indicates that their mid-IR flux can be detected individually, although there is no stacked W3 detection of sources detected in W1 but not W3. Stacking analyses of WISE data for large AGN samples will be a useful tool, and high-redshift QSOs of all types will be easy targets for JWST.
    The Astrophysical Journal 10/2013; 778(2). · 6.73 Impact Factor
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    ABSTRACT: NEOWISE, the NASA planetary-funded extension of the Wide-field Infrared Survey Explorer (WISE) mission, observed over 150,000 minor planets over four infrared wavelength bands (Mainzer et al. 2011). Many of these observed asteroids have associated shapes and spin states derived by the radar community (see current list maintained by L. Benner at http://echo.jpl.nasa.gov lance/shapes/asteroid_shapes.html). Combined, these resources represent a valuable dataset for thermophysical modeling, a technique that combines shape models and infrared observations to determine the thermal inertia of an asteroid, which can indicate composition. However, the large number of objects within this dataset, as well as the detail of the radar shape models (which can be composed of thousands of surface facets), presented a computational challenge. In response, we employ advanced thermal modeling software which allows for full three-dimensional heat conduction, self-heating (via Monte Carlo ray tracing), and surfaces with variable reflective properties. We present thermophysical models using this software, and compare these results to more traditional thermophysical modeling techniques used in the asteroid community.
    10/2013;

Publication Stats

5k Citations
675.75 Total Impact Points

Institutions

  • 1999–2014
    • California Institute of Technology
      • • Infrared Processing and Analysis Center
      • • Jet Propulsion Laboratory
      Pasadena, California, United States
  • 2011–2013
    • Johns Hopkins University
      • Department of Physics and Astronomy
      Baltimore, Maryland, United States
  • 2012
    • University of California, Davis
      Davis, California, United States
    • National Radio Astronomy Observatory
      Charlottesville, Virginia, United States
    • University of Leicester
      • Department of Physics and Astronomy
      Leiscester, England, United Kingdom
  • 2006
    • University of Nottingham
      Nottigham, England, United Kingdom
    • The Royal Observatory, Edinburgh
      Edinburgh, Scotland, United Kingdom
  • 2005–2006
    • University of Virginia
      Charlottesville, Virginia, United States
  • 1987
    • The University of Arizona
      Tucson, Arizona, United States