Daniel Stern
A5030771447- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Pulsars and Gravitational Waves Research
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Radio Astronomy Observations and Technology
- Adaptive optics and wavefront sensing
- Mechanics and Biomechanics Studies
- X-ray Diffraction in Crystallography
- Particle Detector Development and Performance
- Crystallization and Solubility Studies
- High-pressure geophysics and materials
- Cosmology and Gravitation Theories
- Geophysics and Gravity Measurements
- Advanced X-ray Imaging Techniques
- Scientific Research and Discoveries
- Particle Accelerators and Free-Electron Lasers
- Solar and Space Plasma Dynamics
- Calibration and Measurement Techniques
- Dark Matter and Cosmic Phenomena
- Astro and Planetary Science
Temple University
2025
Jet Propulsion Laboratory
2015-2024
California Institute of Technology
2012-2023
Target (United States)
2022
University of Liège
2021
University Corporation for Atmospheric Research
2020
The University of Sydney
2020
Max Planck Institute for Astronomy
2019
Max Planck Society
2019
Diego Portales University
2018
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...
The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on 2012 June 13, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates band from 3 to 79 keV, extending sensitivity of far beyond ∼10 keV cutoff achieved by all previous satellites. inherently low background associated with concentrating light enables probe hard sky a more than 100-fold improvement over collimated or coded mask instruments that have operated this bandpass. Using its unprecedented...
We have discovered 21 new Type Ia supernovae (SNe Ia) with the Hubble Space Telescope (HST) and used them to trace history of cosmic expansion over last 10 billion yr. These objects, which include 13 spectroscopically confirmed SNe at z ≥ 1, were during 14 epochs reimaging GOODS fields North South 2 yr Advanced Camera for Surveys on HST. Together a recalibration our previous HST-discovered Ia, full sample 23 1 provides highest redshift known. Combining these data SN sets, we measured H(z)...
We present Advanced Camera for Surveys, NICMOS, and Keck adaptive-optics-assisted photometry of 20 Type Ia supernovae (SNe Ia) from the Hubble Space Telescope (HST) Cluster Supernova Survey. The SNe were discovered over redshift interval 0.623 < z 1.415. Of these Ia, 14 pass our strict selection cuts are used in combination with world's sample to derive best current constraints on dark energy. new 10 beyond = 1, thereby nearly doubling statistical weight HST-discovered this redshift. Our...
This special issue of the Astrophysical Journal Letters is dedicated to presenting initial results from Great Observatories Origins Deep Survey (GOODS) that are primarily, but not exclusively, based on multiband imaging data obtained with Hubble Space Telescope and Advanced Camera for Surveys (ACS). The survey covers roughly 320 arcmin2 in ACS F435W, F606W, F814W, F850LP bands, divided into two well-studied fields. Existing deep observations Chandra X-Ray Observatory ground-based facilities...
Aims.We study the relationship between local environment of galaxies and their star formation rate (SFR) in Great Observatories Origins Deep Survey, GOODS, at .
We present photometric observations of an apparent Type Ia supernova (SN Ia) at a redshift ~1.7, the farthest SN observed to date. The supernova, 1997ff, was discovered in repeat observation by Hubble Space Telescope (HST) Deep Field-North (HDF-N) and serendipitously monitored with NICMOS on HST throughout Thompson et al. Guaranteed-Time Observer (GTO) campaign. type can be determined from host galaxy type: evolved, red elliptical lacking enough recent star formation provide significant...
Mid-infrared photometry provides a robust technique for identifying active galaxies. While the ultraviolet to mid-infrared continuum of normal galaxies is dominated by composite stellar black body curve and peaks at approximately 1.6 microns, power law. Consequently, with sufficient wavelength baseline, one can easily distinguish AGN from populations. Mirroring tendency be bluer than in ultraviolet, where (and stars) sample blue, rising portion spectra, tend redder mid-infrared, red, falling...
The Wide-field Infrared Survey Explorer (WISE) is an extremely capable and efficient black hole finder. We present a simple mid-infrared color criterion, W1 − W2 ⩾ 0.8 (i.e., [3.4]−[4.6] ⩾0.8, Vega), which identifies 61.9 ± 5.4 active galactic nucleus (AGN) candidates per deg2 to depth of ∼ 15.0. This implies much larger census luminous AGNs than found by typical wide-area surveys, attributable the fact that selection both unobscured (type 1) obscured 2) AGNs. Optical soft X-ray surveys...
We present an updated and revised analysis of the relationship between Hβ broad-line region (BLR) radius luminosity active galactic nucleus (AGN). Specifically, we have carried out two-dimensional surface brightness decompositions host galaxies nine new AGNs imaged with Hubble Space Telescope Wide Field Camera 3. The allow us to create "AGN-free" images galaxies, from which measure starlight contribution optical measured through ground-based spectroscopic aperture. also incorporate 20...
We present evidence for very high gas fractions and extended molecular reservoirs in normal, near-infrared selected (BzK) galaxies at z~1.5, based on multi-configuration CO[2-1] observations obtained the IRAM PdBI. Six of six observed were securely detected. High resolution resolve CO emission four them, implying sizes order 6-11 kpc suggesting presence rotation. The UV morphologies are consistent with clumpy, unstable disks, sizes. star formation efficiencies homogeneously low similar to...
We present new determinations of the cosmic expansion history from red-envelope galaxies. have obtained for this purpose high-quality spectra with Keck-LRIS spectrograph galaxies in 24 galaxy clusters redshift range 0.2 < z 1.0. complement these Keck high-quality, publicly available archival SPICES and VVDS surveys. improve over our previous measurements Simon et al. (2005) by providing two history: H(z) = 97 +- 62 km/sec/Mpc at 0.5 90 40 0.8. discuss uncertainty determination that arises...
We have carried out a survey of the north and south ecliptic poles, EP-N EP-S, respectively, with Spitzer Space Telescope Wide-field Infrared Survey Explorer (WISE). The primary objective was to cross-calibrate WISE Midcourse Experiment (MSX) photometric systems by developing set calibration stars that are common these infrared missions. poles were continuous viewing zones for due its polar-crossing orbit, making areas ideal both absolute internal calibrations. IRAC MIPS imaging covers...
We explore the connection between different classes of active galactic nuclei (AGNs) and evolution their host galaxies, by deriving galaxy properties, clustering, Eddington ratios AGNs selected in radio, X-ray, infrared. study a sample 585 at 0.25 < z 0.8 using redshifts from AGN Galaxy Evolution Survey (AGES) data radio (WSRT 1.4 GHz), X-rays (Chandra XBootes), mid-IR (IRAC Shallow Survey). The IR samples show modest overlap, indicating that to flux limits survey, they represent largely...
We present new improved constraints on the Hubble parameter H ( z ) in redshift range 0.15 < 1.1, obtained from differential spectroscopic evolution of early-type galaxies as a function redshift. extract large sample ∼ 11000) several surveys, spanning almost 8 billion years cosmic lookback time (0.15 1.42). select most massive, red elliptical galaxies, passively evolving and without signature ongoing star formation. Those can be used standard chronometers, firstly proposed by Jimenez...
We have measured the rest--frame lambda~1500 Ang comoving specific luminosity density of star--forming galaxies at redshift 3.5
The COSMOS-Legacy survey is a 4.6 Ms Chandra program that has imaged 2.2 deg$^2$ of the COSMOS field with an effective exposure $\simeq$160 ks over central 1.5 and $\simeq$80 in remaining area. combination 56 new observations, obtained as X-ray Visionary Project, previous C-COSMOS survey. We describe reduction analysis observations properties 2273 point sources detected above spurious probability 2$\times 10^{-5}$. also present updated data. whole includes 4016 (3814, 2920 2440 full, soft...
We have recently completed a 64-night spectroscopic monitoring campaign at the Lick Observatory 3-m Shane telescope with aim of measuring masses black holes in 12 nearby (z < 0.05) Seyfert 1 galaxies expected range ~10^6-10^7 M_sun and also well-studied active galactic nucleus (AGN) NGC 5548. Nine objects sample (including 5548) showed optical variability sufficient strength during to allow for time lag be measured between continuum fluctuations response these broad Hbeta emission. present...
We study the distribution of Eddington luminosity ratios, L_bol/L_edd, active galactic nuclei (AGNs) discovered in AGN and Galaxy Evolution Survey (AGES). combine H-beta, MgII, CIV line widths with continuum luminosities to estimate black hole (BH) masses 407 AGNs, covering redshift range z~0.3-4 bolometric L_bol~10^45-10^47 erg/s. The sample consists X-ray or mid-infrared (24 micron) point sources optical magnitude R<=21.5 mag emission spectra characteristic AGNs. For probed by AGES,...
We present the results of our ultra-deep Keck/DEIMOS spectroscopy z-dropout galaxies in SDF and GOODS-N. For 3 out 11 objects, we detect an emission line at ~ 1um with a signal-to-noise ratio 10. The lines show asymmetric profiles high weighted skewness values, consistent being Lya, yielding redshifts z=7.213, 6.965, 6.844. Specifically, confirm z=7.213 object two independent DEIMOS runs different spectroscopic configurations. z=6.965 is known Lya emitter, IOK-1, for which improved spectrum...
We present ground-based spectroscopic verification of 6 Y dwarfs (see also Cushing et al.), 89 T dwarfs, 8 L and 1 M dwarf identified by the Wide-field Infrared Survey Explorer (WISE). Eighty these are cold brown with spectral types ⩾T6, six which have been announced earlier Mainzer al. Burgasser color–color color–type diagrams showing locus M, L, T, in WISE color space. Near-infrared and, a few cases, optical spectra presented for discoveries. classifications as late early objects peculiar...
We present the serendipitous discovery of molecular gas CO emission lines with IRAM Plateau de Bure interferometer coincident two luminous submillimeter galaxies (SMGs) in Great Observatories Origins Deep Survey North (GOODS-N) field. The identification millimeter as CO[4–3] at z = 4.05 is based on optical and near-IR photometric redshifts, radio-infrared Keck+DEIMOS spectroscopy. These include brightest source field (GN20; S850 μm 20.3 mJy, zCO 4.055 ± 0.001) its companion (GN20.2; 9.9...
We present SEDs, Spitzer colours, and IR luminosities for 850 micron selected galaxies in the GOODS-N field. Using deep Legacy images new data reductions of VLA-HDF radio data, we find statistically secure counterparts 60 per cent (21/35) our submm sample, identify tentative another 12 objects. This is largest sample with detected Spitzer. that most cases emission dominated by a single 24 source. A composite rest-frame SED shows sources peak at longer wavelengths than those local ULIRGs same...