Search Publications
Two Bright Submillimeter Galaxies in a z = 4.05 Protocluster in Goods-North, and Accurate Radio-Infrared Photometric Redshifts
Daddi, E.; Elbaz, D.; Morrison, G. +7 more
We present the serendipitous discovery of molecular gas CO emission lines with the IRAM Plateau de Bure interferometer coincident with two luminous submillimeter galaxies (SMGs) in the Great Observatories Origins Deep Survey North (GOODS-N) field. The identification of the millimeter emission lines as CO[4-3] at z = 4.05 is based on the optical an…
A Critical Assessment of Nonlinear Force-Free Field Modeling of the Solar Corona for Active Region 10953
Leka, K. D.; Cheung, Mark C. M.; Lites, Bruce W. +16 more
Nonlinear force-free field (NLFFF) models are thought to be viable tools for investigating the structure, dynamics, and evolution of the coronae of solar active regions. In a series of NLFFF modeling studies, we have found that NLFFF models are successful in application to analytic test cases, and relatively successful when applied to numerically …
Photometric Redshift and Classification for the XMM-COSMOS Sources
Aussel, H.; Le Floc'h, E.; Sanders, D. B. +40 more
We present photometric redshifts and spectral energy distribution (SED) classifications for a sample of 1542 optically identified sources detected with XMM in the COSMOS field. Our template fitting classifies 46 sources as stars and 464 as nonactive galaxies, while the remaining 1032 require templates with an active galactic nucleus (AGN) contribu…
Red Nuggets at z ~ 1.5: Compact Passive Galaxies and the Formation of the Kormendy Relation
Glazebrook, Karl; McCarthy, Patrick J.; Yan, Haojing +13 more
We present the results of Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) imaging of a sample of 19 high-mass passively evolving galaxies with 1.2 < z < 2, taken primarily from the Gemini Deep Deep Survey (GDDS). Around 80% of galaxies in our GDDS sample have spectra dominated by stars with ages gsim1 Gyr. Our rest-frame R-band i…
The Nature of Flare Ribbons in Coronal Null-Point Topology
Aulanier, G.; Schrijver, C. J.; Masson, S. +1 more
Flare ribbons are commonly attributed to the low-altitude impact, along the footprints of separatrices or quasi-separatrix layers (QSLs), of particle beams accelerated through magnetic reconnection. If reconnection occurs at a three-dimensional coronal magnetic null point, the footprint of the dome-shaped fan surface would map a closed circular ri…
The Space Density of Compton-Thick Active Galactic Nucleus and the X-Ray Background
Treister, E.; Urry, C. Megan; Virani, Shanil
We constrain the number density and evolution of Compton-thick (CT) active galactic nuclei (AGNs). In the local universe, we use the wide-area surveys from the Swift and INTEGRAL satellites, while for high redshifts we explore candidate selections based on a combination of X-ray and mid-infrared (mid-IR) parameters. We find a significantly lower s…
Radio-Loud Narrow-Line Seyfert 1 as a New Class of Gamma-Ray Active Galactic Nuclei
Maraschi, L.; Caraveo, P. A.; Tagliaferri, G. +147 more
We report the discovery with Fermi/LAT of γ-ray emission from three radio-loud narrow-line Seyfert 1 galaxies: PKS 1502+036 (z = 0.409), 1H 0323+342 (z = 0.061), and PKS 2004 - 447 (z = 0.24). In addition to PMN J0948+0022 (z = 0.585), the first source of this type to be detected in γ rays, they may form an emerging new class of γ-ray active galac…
Transits of Earth-like Planets
Kaltenegger, Lisa; Traub, Wesley A.
Transmission spectroscopy of Earth-like exoplanets is a potential tool for habitability screening. Transiting planets are present-day "Rosetta Stones" for understanding extrasolar planets because they offer the possibility to characterize giant planet atmospheres and should provide an access to biomarkers in the atmospheres of Earth-like exoplanet…
Large Area Survey for z = 7 Galaxies in SDF and GOODS-N: Implications for Galaxy Formation and Cosmic Reionization
Ono, Yoshiaki; Ouchi, Masami; Dickinson, Mark +10 more
We present results of our large area survey for z'-band dropout galaxies at z = 7 in a 1568 arcmin2 sky area covering the SDF and GOODS-N fields. Combining our ultra-deep Subaru/Suprime-Cam z'- and y-band (λeff = 1 µm) images with legacy data of Subaru and Hubble Space Telescope, we have identified 22 bright z-dropout g…
Observing the Roots of Solar Coronal Heating—in the Chromosphere
De Pontieu, Bart; McIntosh, Scott W.; Hansteen, Viggo H. +1 more
The Sun's corona is millions of degrees hotter than its 5000 K photosphere. This heating enigma is typically addressed by invoking the deposition at coronal heights of nonthermal energy generated by the interplay between convection and magnetic field near the photosphere. However, it remains unclear how and where coronal heating occurs and how the…