Search Publications
Optical-to-Mid-Infrared Observations of Lyα Galaxies at z~5 in the Hubble Ultra Deep Field: A Young and Low-Mass Population
Malhotra, S.; Rhoads, J. E.; Xu, C. +1 more
High-redshift galaxies selected on the basis of strong Lyα emission tend to be young and have small physical sizes. We show this by analyzing the spectral energy distribution of nine Lyα-emitting galaxies (LAEs) at 4.0<z<5.7 in the Hubble Ultra Deep Field. Rest-frame UV-to-optical (700 Å < λ < 7500 Å) luminosities, or upper limits, are…
The X-Ray Concentration-Virial Mass Relation
Humphrey, Philip J.; Buote, David A.; Brighenti, Fabrizio +4 more
We present the concentration (c)-virial mass (M) relation of 39 galaxy systems ranging in mass from individual early-type galaxies up to the most massive galaxy clusters, (0.06-20)×1014 Msolar. We selected for analysis the most relaxed systems possessing the highest quality data currently available in the Chandra and XMM-Newt…
Beaming Binaries: A New Observational Category of Photometric Binary Stars
Mazeh, Tsevi; Zucker, Shay; Alexander, Tal
The new photometric spaceborne survey missions COROT and Kepler will be able to detect minute flux variations in binary stars due to relativistic beaming caused by the line-of-sight motion of their components. In all but very short period binaries (P>10 days), these variations will dominate over the ellipsoidal and reflection periodic variabili…
The Physical Nature of Rest-UV Galaxy Morphology during the Peak Epoch of Galaxy Formation
Pettini, Max; Erb, Dawn K.; Shapley, Alice E. +5 more
Motivated by the irregular and little-understood morphologies of z~2-3 galaxies, we use nonparametric coefficients to quantify the morphologies of 216 galaxies that have been spectroscopically confirmed to lie at redshifts z=1.8-3.4 in the GOODS-N field. Using measurements of UV and optical spectral lines, multiband photometric data, and stellar p…
Hard X-ray luminosity function and absorption distribution of nearby AGN: INTEGRAL all-sky survey
Sunyaev, R.; Krivonos, R.; Revnivtsev, M. +2 more
Aims:We study the hard X-ray luminosity function and absorption distribution of local (z≲ 0.1) active galactic nuclei (AGN) and discuss the implications for AGN cosmological evolution and for the cosmic X-ray background (CXB).
Methods: We use the INTEGRAL all-sky hard X-ray survey to perform a statistical study of a representative sample of ne…
Coupled Ferric Oxides and Sulfates on the Martian Surface
Mangold, N.; Sotin, C.; Bibring, J. -P. +9 more
The Mars Exploration Rover (MER), Opportunity, showed that layered sulfate deposits in Meridiani Planum formed during a period of rising acidic ground water. Crystalline hematite spherules formed in the deposits as a consequence of aqueous alteration and were concentrated on the surface as a lag deposit as wind eroded the softer sulfate rocks. On …
Iron and Nickel Line Diagnostics for the Galactic Center Diffuse Emission
Maeda, Yoshitomo; Takahashi, Tadayuki; Koyama, Katsuji +14 more
We have observed the diffuse X-ray emission from the Galactic Center (GC) using the X-ray Imaging Spectrometer (XIS) on Suzaku. The high-energy resolution and the low-background orbit provided excellent spectra of the GC diffuse X-rays (GCDX). The XIS found many emission lines in the GCDX near the energy of K-shell transitions of iron and nickel. …
The Kormendy relation of massive elliptical galaxies at z ~ 1.5: evidence for size evolution
Mannucci, F.; Bender, R.; Longhetti, M. +6 more
We present the morphological analysis based on HST-NIC2 (0.075 arcsec pixel-1) images in the F160W filter of a sample of nine massive field (>1011Msolar) galaxies spectroscopically classified as early-types at 1.2 < z < 1.7. Our analysis shows that all of them are bulge-dominated systems. In particular, si…
SPICAV on Venus Express: Three spectrometers to study the global structure and composition of the Venus atmosphere
Bertaux, Jean-Loup; Dimarellis, E.; Reberac, A. +33 more
Spectroscopy for the investigation of the characteristics of the atmosphere of Venus (SPICAV) is a suite of three spectrometers in the UV and IR range with a total mass of 13.9 kg flying on the Venus Express (VEX) orbiter, dedicated to the study of the atmosphere of Venus from ground level to the outermost hydrogen corona at more than 40,000 km. I…
The Redshift Evolution of Early-Type Galaxies in COSMOS: Do Massive Early-Type Galaxies Form by Dry Mergers?
Kneib, J. -P.; Aussel, H.; Cimatti, A. +26 more
We study the evolution since z~1 of the rest-frame B luminosity function of ETGs in ~0.7 deg2 in the COSMOS field. In order to identify all progenitors of local ETGs we construct the sample of high-z galaxies using two complementary criteria: (1) a morphological selection based on the Zurich Estimator of Structural Types and (2) a photo…