A5037446717- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Molecular Spectroscopy and Structure
- Atmospheric Ozone and Climate
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Spacecraft and Cryogenic Technologies
- Spectroscopy and Laser Applications
- Space Exploration and Technology
- Adaptive optics and wavefront sensing
- Galaxies: Formation, Evolution, Phenomena
- Calibration and Measurement Techniques
- Advanced Combustion Engine Technologies
- High-pressure geophysics and materials
- History and Developments in Astronomy
- Geophysics and Gravity Measurements
- Advanced Chemical Physics Studies
- Infrared Target Detection Methodologies
- Scientific Research and Discoveries
- Phase Equilibria and Thermodynamics
- Atomic and Molecular Physics
- Radio Astronomy Observations and Technology
University of Toledo
2016-2025
Max Planck Institute for Radio Astronomy
1994-2015
Lowell Observatory
2014
Center for Astrophysics Harvard & Smithsonian
1999-2009
National Aeronautics and Space Administration
2004-2008
Association of Universities For Research In Astronomy
2008
U.S. National Science Foundation
2008
Kitt Peak National Observatory
2008
Harvard University
2003-2006
Harvard University Press
2004-2006
The Infrared Array Camera (IRAC) is one of three focal plane instruments in the Spitzer Space Telescope. IRAC a four-channel camera that obtains simultaneous broad-band images at 3.6, 4.5, 5.8, and 8.0 microns. Two nearly adjacent 5.2x5.2 arcmin fields view are viewed by four channels pairs (3.6 5.8 microns; 4.5 8 microns). All detector arrays 256x256 pixels size, with two shorter wavelength using InSb longer Si:As IBC detectors. powerful survey instrument because its high sensitivity, large...
We present a uniform mid-infrared imaging and photometric survey of 36 young, nearby, star-forming clusters groups using {\it Spitzer} IRAC MIPS. have confidently identified classified 2548 young stellar objects recently established color-based methods. devised applied new algorithm for the isolation local surface density enhancements from point source distributions, enabling us to extract overdense cores observed star forming regions further analysis. compiled several basic structural...
Element-by-element we have combined the optical components in three 2MASS cameras, and incorporated detector quantum efficiency curves site-specific atmospheric transmissions, to create relative spectral response (RSRs). We provide absolute attributes associated with "zero magnitude" JHKs bands so that these RSRs may be used for synthetic photometry. The tie Cohen-Walker-Witteborn framework of photometry spectra purpose using data support development calibrators IRAC pairwise...
We present Spitzer Space Telescope infrared photometric time series of the transiting extrasolar planet system TrES-1. The data span a predicted secondary eclipse, corresponding to passage behind star. In both bands our observations, we detect flux decrement with timing, amplitude, and duration as by published parameters system. This signal represents first direct detection (i.e. observation photons emitted by) orbiting another observed eclipse depths (in units relative flux) are 0.00066 +/-...
We report new Spitzer Space Telescope observations from the IRAC and MIPS instruments of young (~ 3 Myr) sigma Orionis cluster. identify 336 stars as members cluster using optical near-infrared color magnitude diagrams. Using spectral energy distribution (SED) slopes in range, we place objects several classes: non-excess stars, with optically thick disks(like classical T Tauri stars), class I (protostellar) candidates, ``evolved disks''; last exhibit smaller excesses than disk systems. In...
The Infrared Array Camera (IRAC) on the Spitzer Space Telescope is absolutely calibrated by comparing photometry a set of A stars near north ecliptic pole to predictions based ground-based observations and stellar atmosphere model. brightness point sources an accuracy 3%, relative models for star atmospheres, performed analyzed in same manner as calibration stars. This includes corrections location array if centroid within peak pixel. Long-term stability IRAC was measured monitoring dwarfs K...
We present multiband photometry of 185 type-Ia supernovae (SNe Ia), with over 11,500 observations. These were acquired between 2001 and 2008 at the F. L. Whipple Observatory Harvard-Smithsonian Center for Astrophysics (CfA). This sample contains largest number homogeneously observed reduced nearby SNe Ia (z ≲ 0.08) published to date. It more than doubles sample, bringing SN cosmology point where systematic uncertainties dominate. Our natural system has a precision ≲0.02 mag in BVRIr'i' ≲0.04...
We estimate the strength of bandpass-integrated thermal emission from extrasolar planet HD 209458b at 3.6, 4.5, 5.8, and 8.0 microns using Infrared Array Camera (IRAC) on Spitzer Space Telescope. observe a single secondary eclipse simultaneously in all four bandpasses find relative depths 0.00094 +/- 0.00009, 0.00213 0.00015, 0.00301 0.00043, 0.00240 0.00026, respectively. These reveal that shape inferred spectrum for differs significantly predictions standard atmosphere models; instead most...
We present near- and mid-infrared photometry obtained with the Spitzer Space Telescope of ∼300 known members IC 348 cluster. merge this existing ground-based optical near-infrared in order to construct optical-infrared spectral energy distributions (SEDs) for all cluster a complete atlas these SEDs. employ observations investigate both frequency nature circumstellar disk population The span wavelength range between 3.6 24 μm, corresponding radii ∼0.1-5 AU from central star. are sufficiently...
We compare the infrared colors predicted by theoretical models of protostellar envelopes and protoplanetary disks with initial observations young stellar objects made Infrared Array Camera (IRAC) on Spitzer Space Telescope. Disk envelope characterized infall and/or accretion rates found in previous studies can quantitatively account for range IRAC four embedded clusters: S140, S171, NGC 7129, Cep C. The color-color diagram ([3.6]-[4.5] vs. [5.8]-[8.0]) be used to help distinguish between...
We present a comprehensive analysis of structure in the young, embedded cluster, NGC 1333 using members identified with Spitzer and 2MASS photometry based on their IR-excess emission. In total, 137 are this way, composed 39 protostars 98 more evolved pre-main sequence stars disks. Of latter class, four transition/debris disk candidates. The fraction exposed disks is 83% +/- 11%, showing that there measurable diskless population. sources each Class I II evolutionary states shown to have very...
We present a survey of the Orion A and B molecular clouds undertaken with IRAC MIPS instruments onboard Spitzer. In total, five distinct fields were mapped covering 9 sq. degrees in mid-IR bands spanning 3-24 microns. The includes Nebula Cluster, Lynds 1641, 1630 1622 dark clouds, NGC 2023, 2024, 2068 2071 nebulae. These data are merged 2MASS point source catalog to generate eight band photometry. identify 3479 dusty young stellar objects (YSOs) by searching for sources colors indicative...
We present UBVRI photometry of 44 Type Ia supernovae (SNe Ia) observed from 1997 to 2001 as part a continuing monitoring campaign at the Fred Lawrence Whipple Observatory Harvard-Smithsonian Center for Astrophysics. The data set comprises 2190 observations and is largest homogeneously reduced sample SNe date, nearly doubling number well-observed, nearby with published multicolor CCD light curves. large U-band unique addition, important connections high redshift. decline rate SN curves...
We present an independent estimate of the interstellar extinction law for Spitzer IRAC bands as well a first attempt at extending to 24micron MIPS band. The source data these measurements are observations five nearby star-forming regions: Orion A cloud, NGC 2068/71, 2024/23, Serpens and Ophiuchus. Color excess ratios E(H-Ks)/E(Ks-[lambda]) were measured stars without infrared dust emission from circumstellar disks/envelopes. For four regions, laws similar all wavelengths differ...
We present a global study of low mass, young stellar object (YSO) surface densities in nearby (< 500 pc) star forming regions based on comprehensive collection Spitzer Space Telescope surveys. show that the distribution YSO solar neighbourhood is smooth distribution, being adequately described by lognormal function from few to 10^3 YSOs per pc^2, with peak at 22 stars/pc^2 and dispersion 0.85. do not find evidence for multiple discrete modes star-formation (e.g. clustered distributed)....
We present key results from the Herschel Orion Protostar Survey (HOPS): spectral energy distributions (SEDs) and model fits of 330 young stellar objects, predominantly protostars, in molecular clouds. This is largest sample protostars studied a single, nearby star-formation complex. With near-infrared photometry 2MASS, mid- far-infrared data Spitzer Herschel, sub-millimeter APEX, our SEDs cover 1.2-870 $\mu$m peak protostellar envelope emission at ~100 $\mu$m. Using mid-IR indices bolometric...
Abstract Investigating Protostellar Accretion (IPA) is a JWST Cycle 1 GO program that uses NIRSpec integral field units and MIRI Medium Resolution Spectrograph to obtain 2.9–28 μ m spectral cubes of young, deeply embedded protostars with luminosities 0.2–10,000 L ⊙ central masses 0.15–12 M . In this Letter, we report the discovery highly collimated atomic jet from Class 0 protostar IRAS 16253−2429, lowest-luminosity source ( bol = 0.2 ) in IPA program. The detected multiple [Fe ii ] lines...
We present the results of an infrared imaging survey two clusters in Cep OB2 Association, Tr 37 and NGC 7160, using IRAC MIPS instruments on board Spitzer Space Telescope. Our observations cover wavelength range from 3.6 to 24 μm, allowing us detect disk emission over a typical radii ~0.1 ~20 AU central star. In 37, with age about 4 Myr, 48% low-mass stars exhibit detectable bands. Roughly 10% disks may be "transition" objects, essentially photospheric fluxes at wavelengths ≤4.5 μm but...
We present infrared photometry obtained with the IRAC camera on Spitzer Space Telescope of a sample 82 pre-main-sequence stars and brown dwarfs in Taurus star-forming region. find clear separation some color-color diagrams between objects without disks. A few "transition" are noted, which correspond to systems inner disk has been evacuated small dust. Separating pure from remnant protostellar envelopes is more difficult at wavelengths, especially for infall low rates large angular momenta....
We report the discovery of T dwarf companions to nearby stars HN Peg (G0V, 18.4 pc, ~0.3 Gyr) and HD 3651 (K0V, 11.1 ~7 Gyr). During an ongoing survey 5'x5' fields surrounding in solar neighborhood with IRAC aboard Spitzer Space Telescope, we identified these as candidate dwarfs based on their mid-IR colors. Using near-IR spectra obtained SpeX at NASA IRTF, confirm presence methane absorption that characterizes measure spectral types T2.5+/-0.5 T7.5+/-0.5 for B B, respectively. By comparing...
We present initial results from time-series imaging at infrared wavelengths of 0.9 deg2 in the Orion Nebula Cluster (ONC). During Fall 2009 we obtained 81 epochs Spitzer 3.6 and 4.5 μm data over 40 consecutive days. extracted light curves with ∼3% photometric accuracy for ∼2000 ONC members ranging several solar masses down to well below hydrogen-burning mass limit. For many stars, also have photometry optical (Ic) and/or near-infrared (JKs) wavelengths. Our set can be mined determine stellar...
We present Spitzer Space Telescope time series photometry of the exoplanet system HD 189733 spanning two times secondary eclipse, when planet passes out view behind parent star. estimate relative eclipse depth in five distinct bands and find planet-to-star flux ratio to be 0.256% ± 0.014% (3.6 μm), 0.214% 0.020% (4.5 0.310% 0.034% (5.8 0.391% 0.022% (8.0 0.598% 0.038% (24 μm). For consistency, we reanalyze a previously published deduce contrast an additional band, 0.519% (16 Our data are...
We present extensive optical and infrared photometry of the afterglow gamma-ray burst (GRB) 030329 its associated supernova (SN) 2003dh over first two months after detection (2003 March 30-May 29 UT). Optical spectroscopy from a variety telescopes is shown and, when combined with photometry, allows an unambiguous separation between SN contributions. The GRB initially power-law continuum but shows significant color variations during week that are unrelated to presence SN. early light curve...
We report the discovery and characterization of a power-law correlation between local surface densities Spitzer-identified, dusty young stellar objects (YSOs) column density gas (as traced by near-IR extinction) in eight molecular clouds within 1 kpc with 100 or more known YSOs. This correlation, which appears data smoothed over size scales ∼1 pc, varies quality from cloud to cloud; those tight correlations, MonR2 Ophiuchus, are fit power laws slope 2.67 1.87, respectively. The spread is...